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Two-year clinical evaluation of a pit and fissure sealant. Part I: Retention and loss of substance
Sealant was completely retained on 92% of all teeth at 3 months and on 69% of all teeth at 24 months. Retention was superior on premolars compared with molars, on second premolars compared with first premolars, and on first molars compared with second molars.
Two-year clinical evaluation of a pit and fissure sealant. Part I: Retention and loss of substance
Robert E. Going, DDS, MS Larry D. Haugh, PhD David A. G rainger, DDS Anthony J. Conti, DMD, MPH, Gainesville, Fla
A pit and fissure sealant was applied to the teeth of children between 10 and 14 years of age to evaluate the retention and loss of sealant substance over a two-year period. The sealant was fully retained on 92% of all paired, permanent teeth at 3 months, on 86% at 6 months, 81 % at 12 months, and 69% at 24 months. Twenty-three of 24 occlusal pit regions evaluated at 24 months showed a predominance of substance loss ranging from slight to severe, with the latter more prevalent. The single exception was the distal pit of the maxillary second molar, which showed no retention of the sealant in 83% of the teeth.
388 ■ JADA, Vol. 92, February 1976
Preventing caries from developing in the pits and fissures of teeth has been of practical impor tance for some time and has generated an exten sive search for methods and materials that might control the occlusal caries problem .1' 14 Recent attempts to seal and protect pits and fissures from caries use organic polymers that adhere to the enamel adjacent to pit and fissure defects. The first comprehensive report of sealing the highly susceptible pits and fissures of teeth with an adhesive resin was published in 1967.15 Sub sequent clinical trials using sealants based on the reaction product of bisphenol A and glycidyl methacrylate (BIS-GMA) have used different mixtures of the base polymers, different applica tion techniques, and different curing methods. Nuva-Seal* and Epoxylite Fissure Sealant 9075t have been used in clinical applications and have received recognition as agents for restoring or sealing off anatomically deficient surfaces of teeth .16 The purpose of this study was to evaluate more comprehensively the clinical retention and loss of substance of a single application of a pit and fissure sealant and to determine the influence this protective coating might have on caries ac tivity in teeth over a two-year period. Nuva-Seal was selected to be used in this study on the basis of its proven success in previous clinical stud ies.17'23 This paper reports the results related to the retention and loss of substance of the pit and fis
sure sealant. A subsequent paper (March j a d a ) will report on the caries-protective efficacy of the sealant after two years of clinical service.
M aterials and methods
Eighty-four children, ranging in age from 10 to 14 years, were chosen after preliminary examina tion from the fifth through eighth grades of a single school in a stable, integrated community of low-income families in the nonfluoridated rural area of Alachua, Fla. An approximately uniform distribution of children with respect to sex and race was used, with only four children in the 14-year-old age group. For the study, 479 sound, paired permanent teeth and 20 paired deciduous teeth were coated under controlled clinical conditions with a methacrylate-type polymer, Nuva-Seal, and poly merized by ultraviolet light (Nuva-Lite*). A red dye (F D & C no. 17 Redt) was added to the seal ant by the manufacturer to assist in visualizing the placement and subsequent evaluation of the sealant’s retention and loss of substance. A half mouth technique was used; one side of the mouth of each patient was randomly selected for treatm ent, and the other served as the untreated control. The treated teeth and their contralateral controls were considered study pairs. Fifty-two unpaired teeth also were coated with Nuva-Seal, but were not included in most of the final analy ses. Baseline examination and treatment proce dures were completed in the dental clinic at the University of Florida College of Dentistry. All patients were routed through five stations, each staffed with a dentist and chairside assistant as signed to complete a specific function. Before the teeth were coated with sealant, each child received a prophylaxis at station 1 with a fluoride-free cleaning and polishing paste carried to the tooth surfaces with a rubber cup. The mouth was irrigated thoroughly to remove the cleansing agent, and the patient was directed to station 2 where a baseline examination was made with a dental mirror and sharp no. 23 ex plorer under dry, well-lighted conditions. The pits and fissures of each tooth were scored and recorded on a treatment and evaluation record according to a rating scale similar to that used by Buonocore.17 Numerals of 0 (caries free) to 4 (severe caries) were assigned, since not all teeth included in this study were caries free. In addi
tion, the location of all explorer catches (rating of 2), penetration of the explorer (rating of 3), and large carious lesions (rating of 4) were noted on an anatomic diagram of each tooth that appeared adjacent to the rating column. Mesial, central, and distal pit regions were differentiated for pos terior teeth; only the lingual pit region was noted for maxillary incisors. Conditioning of the teeth with the Nuva-System Tooth Conditioner* (50% phosphoric acid buffered with 7% zinc ox ide) and application and polymerization of the sealant were accomplished at either station 3 or 4. To maintain optimal dryness of the tooth sur faces after etching, washing, and application of compressed air, the dentist conditioning the teeth and the dentist applying the sealant were rotated between stations 3 and 4. The patient and the assigned dental assistant, on the other hand, remained stationary until both procedures were completed, following the instructions pro vided by the manufacturer. From the condition ing phase through the application and polymer ization of the sealant, the teeth to be treated were maintained in a dry state with use of cotton rolls and saliva ejectors. A t station 5 all treated teeth were scrutinized for correct application of the sealant, and records were checked for accur acy and completeness. Evaluation of the treated and control teeth for each patient was done at intervals of 3, 6, 12, and 24 months by two independent examiners at the grade school in Alachua. Rating disagreements between examiners were resolved during a joint examination before the patient was dismissed. New evaluation forms were used at each time interval to prevent the examiners from being biased by previous ratings. The use of portable dental equipment in a simulated clinical environ ment permitted sufficient flexibility to retain in the study a small number of children who trans ferred to other schools in the same county. Retention and loss of sealant substance for each pit region was evaluated by visual inspec tion and dental explorer and rated on a four-point scale, “ a” through “ d .” N o apparent loss of sub stance received an “ a” rating, slight loss of sub stance a “ b” rating, severe loss of substance a “ c” rating, and total loss of substance (no reten tion) a “ d ” rating. Although “ a ,” “ b ,” and “ c” ratings indicated retention of the material, more specifically they rated the amount of substance lost. Therefore, each tooth was scored as having the sealant missing when all pit regions were rat ed “ d ,” sealant partly missing when at least one pit region was rated “ d ,” and sealant present G oing— others: CLINICAL EVALUATION OF A SEALANT ■ 389
Table 1 ■ N u m b e r o f i n i t i a l l y s o u n d p a i r e d a n d u n p a i r e d t e e t h a v a il a b le a t v a r i o u s c l i n i c a l e x a m i n a t i o n s .
Examination Baseline 3 mo 6 mo 12 mo 24 mo
No. children 84 83 77 79 70
T reated/ control pairs 479 475 448 454 404
(20)’ (16) (8) (9) (4)
T reated unpaired 39 37 32 39 31
(13) (15) (7) (6) (2)
C ontrol unpaired 37 37 35 37 32
(9) (7) (2) (4) (1)
Treated total 518 512 480 493 435
(33) (31) (15) (15) (6)
C ontrol total 516 512 483 491 436
(29) (23) (10) (13) (5)
'P rim ary teeth in parentheses; perm anent teeth w ith o u t parentheses.
when each pit region remained coated and rated with either an “ a ,” “ b ,” or “ c .” Teeth with transverse ridges were not evaluated in the cen tral pit region. Porosity, peeling, and ledging of the sealant material also were evaluated. Surface porosity was evident as small holes on the surface of the sealant material. When present, it was demon strated best by visual inspection and an explorer tyne carried lightly across the polymerized sur face. Peeling and ledging were discerned both visually and by explorer at the junction of the polymerized sealant and the enamel surface. Peeling was defined as a loosening and slight lift ing of the edges of the sealant from the enamel. Ledging was defined as loss of the peeled edge, leaving a slightly elevated, firm, steplike margin of sealant.
R esults
The number of children available for examina tion at the 3-, 6-, 12-, and 24-month time inter vals was 83, 77, 79, and 70 respectively. Thus, after two years, 83% of the original children re mained in the study. Of the 16 children unavail able at one or more examinations, there were more white children missing than black children (12 versus 4) and more 12 year olds (7) than chil dren in any other single age group. No impor tant bias was evident as a result of these factors. The number of initially sound paired and un paired teeth available for all examinations is pre sented in Table 1. The median number of study pairs per child at the baseline examination was six, with 81% of the children having between four and eight pairs available for sealant applica tion. After one year, 95% of the paired perma nent teeth were available for examination, and after two years 84%. In the analysis of data on sealant retention and loss of substance, the various time intervals (four examinations), number of different teeth (eight to ten), anatomic regions of the occlusal surface 390 ■ JADA, Vol. 92, February 1976
(one to three pit regions), and substance loss (four-point scale) were related one to another. For example, plots of retention rates against time permitted evaluation of how quickly sealant ad herence dropped in time, and certain composite bar graphs permitted comparisons between dif ferent teeth or anatomic regions for the data deal ing with loss of substance. ■ S ea la n t retention: Nuva-Seal was completely retained on 92% of all paired, permanent teeth at 3 months, 86% at 6 months, 81% at 12 months, and 69% at 24 months (Fig 1 and Tables 2 and 3). The proportion of teeth losing all sealant was only 1% from the baseline examination to 6 months of service, 2% at 12 months, and 8% at 24 months. Figure 1 indicates a relatively sharp decrease in retention for the period up to six months, but a linear trend for the time per iods beyond six months. The slope of this linear trend indicates that approximately 1% of the teeth were losing part or all of their sealant per month. With the exception of the maxillary second molars, the sealant was retained well on all mo lars, premolars, and lingual surfaces of maxilSEALANT
□ ES
T IM E
MISSING
SEALANT PARTLY MISSING S E ALAN T
PRESENT
P E R IO D (M O N T H S )
Fig 1 ■ Sealant retention on paired perm anent teeth at 3, 6, 12, and 24 m onths.
Table 2 ■ Sealant retention on paired permanent teeth at 12 months. Sealant all missing
Sealant partly missing
Sealant all present
Teeth examined
No.
No.
%
No.
%
No.
%
95% Cl*
All teeth All maxillary teeth All mandibular teeth All molars All premolars Maxillary first premolars Mandibular first premolars Maxillary second premolars Mandibular second premolars Maxillary first molars Mandibular first molars Maxillary second molars Mandibular second molars Maxillary incisors
454 241 213 170 253 64 70 59 60 47 49 40 34 31
11 6 5 5 5 1 4 0 0 1 0 3 1 1
2.4 2.5 2.3 2.9 2.0 1.6 5.7 0.0 0.0 2.1 0.0 7.5 2.9 3.2
76 43 33 51 23 2 12 3 6 12 8 24 7 2
16.7 17.8 15.5 30.0 9.1 3.1 17.1 5.1 10.0 25.5 16.3 60.0 20.6 6.5
367 192 175 114 225 61 54 56 54 34 41 13 26 28
80.8 79.7 82.2 67.1 88.9 95.3 77.1 94.9 90.0 72.3 83.7 32.5 76.5 90.3
(77-84) (75-85) (76-87) (59-74) (85-93) (86-99) (65-86) (86-99) (80-96) (57-84) (71-93) (11-41) (59-89) (74-98)
*95% confidence intervals derived from published tables.25
Table 3 ■ Sealant retention on paired permanent teeth at 24 months. Sealant all missing
Sealant partly missing
Sealant all ______ present
Teeth examined
No.
No.
%
No.
%
No.
%
95% c r
All teeth All maxillary teeth All mandibular teeth All molars All premolars Maxillary first premolars Mandibular first premolars Maxillary second premolars Mandibular second premolars Maxillary first molars Madibular first molars Maxillary second molars Mandibular second molars Maxillary incisors
404 217 187 152 225 59 60 53 53 42 44 36 30 27
33 22 11 14 14 3 7 4 0 3 2 7 2 5
8.2 10.1 5.9 9.2 6.2 5.1 11.7 7.5 0.0 7.1 4.5 19.4 6.7 18.5
91 53 38 67 22 6 5 3 8 18 13 24 12 2
22.5 24.4 20.3 44.1 9.8 10.2 8.3 5.7 15.1 42.9 29.5 66.7 40.0 7.4
280 142 138 71 189 50 48 46 45 21 29 5 16 20
69.3 65.4 73.8 46.7 84.0 84.7 80.0 86.8 84.9 50.0 65.9 13.9 53.3 74.1
(65-74) (59-72) (67-80) (39-55) (79-89) (73-93) (68-89) (75-95) (73-93) (34-66) (50-80) ( 5-29) (34-72) (54-89)
*95% confidence interval using normal approximation to the binomial distribution, except when approximation is poor.
lary incisors through 12 months. The sealant was totally present on all tooth types at least at an 87% retention level at three months and a 79% level at six months, compared with only a 61% and a 40% retention level respectively, for the maxillary second molars (data not shown). A further decrease in complete retention to 33% and 14% was found for the maxillary second mo lars at 12 and 24 months, whereas all other types of teeth showed retention generally above 72% and 50% for these same time periods. Retention of sealant on premolars was found superior to retention on molars for all time per iods, with 84% of the premolars remaining com pletely sealed up to 24 months compared with only 47% of the molars. A t all four evaluation periods, the retention of sealant on second pre molars was superior to retention on first pre molars, and retention on first molars was always superior to that on second molars. Also, sealant retention in the mandibular arch was slightly superior, in general, to that in the maxillary arch. F or example, at 24 months, 74% of the mandib ular teeth had sealant all present compared with 65% for those in the maxillary arch. Since estimates of retention rates are based on
those children selected for the study, it is useful to calculate confidence intervals for retention rates as an expression of the uncertainty that necessarily exists in attempting to select a truly representative group of children.24 The intervals given in Tables 2 and 3 are 95% certain to con tain the true complete retention rates for all sim ilar children. Figure 2 illustrates how sealant retention rates for premolars and molars decrease with time. The retention rates are percentages of those teeth available for examination at each time per iod. As in Figure 1, a linear trend is generally evident between time periods, especially after six months. This trend depends on tooth type; for example, the molars show greater rates of decline than do the premolars. The small, ap parent increase in retention from 12 to 24 months for mandibular first premolars is probably the re sult of either the small differences in the number of children involved or slight judgmental differ ences in assessing retention at each time period. Sealant retention for the unpaired permanent teeth was generally not as good as that found for paired permanent teeth. A more detailed com parison is of little value, however, since only 31 G oing— others: CLINICAL EVALUATION OF A SEALANT ■ 391
tia I
SEALANT M IS SIN G 1 SEALANT PARTLY MISSING
[ 3
3
6
UPPER
12 24 FIRST
PREMOLARS
3
6
12
24
SEALANT
3
LOWER FIRST PREMOLARS
6
12
PRESENT
24
3
6
LOWER SECOND
PREMOLARS
PREMOLARS
100 8070 605040
W M
■É
90-
t
3020
I o-
0 3
6
12 24
UPPER F IR S T MOLARS
iI 6
12 24
LOWER FIR S T MO LARS
T IM E
3
12 2 4
UPPER SECOND
6
12
24
UPPER SECOND MOLARS
6
12 24
LOWER SECOND MOLARS
PERIOD (MONTHS)
Fig 2 ■ Sealant retention on paired prem olars (top) and perm anent molars (bottom ) at 3, 6, 12, and 24 months.
treated, unpaired teeth were available for exam ination at 24 months. Similarly, no useful com parisons could be made for the deciduous teeth. The retention experience of those patients missing certain examinations was not significant ly different from those who were present. For example, the nine patients who were lost from the study between the 12- and 24-month exam ination periods had retention rates at 12 months that were comparable to those of patients who continued to 24 months. ■ L o ss o f su b sta n ce a n d retention by an atom ic region: Loss of sealant substance and retention were evaluated for the mesial, central, and distal pit regions of posterior teeth, as well as the lin gual pit region of maxillary incisors. 392 ■ JADA, Vol. 92, February 1976
At the three-month examination, substance loss was visually and functionally apparent in most pit regions. This result was anticipated, since no children complained of hyperocclusion on the treated side, a factor that was present at initial placement. The mesial pit region of all molars and premolars, in general, showed a greater extent of severe loss of substance than either the central or distal pit regions, and the severe loss was more noticeable in molars than in premolars (Fig 3). Figure 3, top, also shows that the maxillary first molars had the greatest frequency of severe loss of substance in the me sial pit region (92%), yet the sealant was com pletely missing from this area (no retention) in only 6% of the children. To summarize loss of substance by anatomic region at three months, the three pit regions for all posterior teeth except one type showed dis cernible differences in rates of substance loss. The single exception was the mandibular second premolars, which received nearly the same dis tribution of loss of substance ratings in all three pit regions at three months. The three pit regions that showed the poorest retention of the sealant at three months were the distal pits of the maxil lary and mandibular second molars and the me sial pit of the mandibular first premolars (37%, 9%, and 12% no retention, respectively). At 24 months the degree of substance loss was substantially increased over that found at 3 months. The percentage of “ no loss of sub stance” ratings never exceeded 10% in any of the 24 anatomic regions evaluated (Table 4), whereas at three months the comparable statistic was 51% (compare Fig 3, top and bottom). The initial loss of substance from the baseline exam ination to 3 months was significant, and the fur ther reduction at 24 months indicates continued substance loss. The relative differences in substance loss be tween the mesial, central, and distal pit regions decreased at 24 months (Fig 3, bottom). In con trast to the pattern at three months, no one re gion was uniformly better for all teeth. Twentythree of the 24 anatomic areas showed substance loss ranging predominantly from slight to severe, with the latter now more prevalent than at three months (compare Fig 3, top and bottom). The single exception was the distal pit of the max illary second molars where “ no retention” of the sealant was predominant. At 24 months, the three pit areas that showed the poorest reten tion of the sealant were the distal pits of the max illary and mandibular second molars and the
i ü
o * NO LOSS OF SUBSTANCE
I
I
b = SLIGHT LOSS OF SUBSTANCE C - SEVERE LOSS OF SUBSTANCE d * NO RETENTION
M C UPPER F IR S T PREMOLARS
AREA:
LOWER F IR ST PREMOLARS
UPPER SECOND PREMOLARS
M - MESIAL PIT AREA
C - CENTRAL
M C
D
PIT AREA
D
UPPER SECOND MOLARS
LOWER. FIR ST MOLARS
LOWER SECOND PREMOLARS
D - D IS T A L P I T
AREA
JOO
Fig 3 ■ Loss of substance and retention by anatomic region for paired permanent teeth at 3 months (top) and at 24 months (bottom).
UPPER FIRST PREMOLARS
AREA
LOWER FIRST PREMOLARS
UPPER SECOND PREMOLARS
M - MESIAL PIT AREA
LOWER SECOND PREMOLARS
UPPER FIRST MOLARS
C - CENTRAL PIT AREA
D " DISTAL PIT AREA
Table 4 ■ Loss of substance and retention by anatomic region on paired permanent teeth at 24 months.* Mesial pit regionf Tooth type
No.
Maxillary first premolar Mandibular first premolarf Maxillary second premolar Mandibular second premolar§ Maxillary first molar Mandibular first molar Maxillary second molar Mandibular second molar
59 60 53 53
a 0.0 0.0 0.0 1.9
42 44 36 30
0.0 0.0 0.0 0.0
b 10.2 20.0 3.8 13.2
c 78.0 65.0 86.8 79.3
0.0 0.0 2.8 3.3
57.1 84.1 66.7 76.7
Central pit region d
Distal pit region
b
c
d
11.9 15.0 9.4 5.6
a 0.0 0.0 0.0 2.0
11.9 7.1 22.6 7.8
81.4 67.9 67.9 84.3
42.9 15.9 30.6 20.0
0.0 0.0 5.6 10.0
9.5 15.9 41.7 30.0
71.4 75.0 27.8 50.0
b
6.8 25.0 9.4 5.9
a 0.0 0.0 0.0 3.8
28.8 43.4 15.1 43.4
c 62.7 41.7 73.6 43.4
8.5 15.0 11.3 9.4
d
19.0 9.1 25.0 10.0
?,4 00 8.3 3.3
28.6 6.8 8.3 6.7
50.0 70.5 0.0 46.7
19.0 22.7 83.3 43.3
'Figures reported are percentages of teeth having the specified substance loss in a particular region, fa, no loss of substance; b, slight loss of substance; c, severe loss of substance; d, no retention. ^Number o f central p it regions evaluated is 28. ¿Number of central pit regions evaluated is 51.
mesial pit of the maxillary first molars (83%, 43%, and 43% “ no retention,” respectively). The mandibular second premolars showed the best collective retention in their three pit regions, with only 6%, 6%, and 9% “ no retention,” re
spectively. The temporal patterns of sealant loss by ana tomic regions for mandibular second premolars and maxillary second molars are presented in Figure 4, thus exemplifying the best and worst G oing— others: CLINICAL EVALUATION OF A SEALANT ■ 393
u ro a
a " no U3ss o f substanc e
C3
b»SLIGHT LOSS OF SUBSTANCE
the retention and loss of substance results (Table
5).
C* SEVERE LOSS OF SUBSTANCE KKR3 d«NO RETENTION
3
6
12
24
3
6
MESIAL PIT AREA
T IM E
3
6
12
12
24
3
6
CENTRAL PIT AREA
24
MESIAL PIT AREA
3
. 24
DISTAL PIT AREA
P E R IO D (M O N T H S )
6
12
24
3
CENTRAL PIT AREA T IM E
12
F or posterior teeth, porosity in the sealant reached a peak incidence of 5% after 12 months. Peeling reached a peak of 4% at six months and declined thereafter, whereas ledging was noted more frequently after one year (17%) and con tinued to a high of 27% after 24 months. For inci sors, porosity was not noted in the approxi mately 30 teeth evaluated, and peeling and ledg ing followed a pattern similar to that found on posterior teeth, but at a higher level. In an attempt to check possible connections between peeling and either ledging or sealant loss, the 28 teeth that demonstrated peeling of the sealant at either the 3- or 6-month examina tions (and not missing at 24 months) were more carefully scrutinized. Twelve (43%) showed evi dence of ledging by 24 months and only ten (36%) had completely lost the sealant. Of the remaining six teeth, five appeared normal at the latter ex amination and one continued to show peeling.
PE RIO D
6
12
24
DISTAL PIT AREA
(M O N T H S )
Discussion Fig 4 ■ Loss of substance and retention by anatomic region for paired mandibular second premolars (top) and permanent maxil
The two-year retention results reported in this study corroborate the essential findings of Buonocore,18 Rock,22 and Horowitz and co-workers.23 After two years of clinical use, Buonocore re ported the teeth to be fully sealed at an 87% level; Rock reported an 80% level; Horowitz, a 73% level; and this study, a 69% level. Because surface morphology apparently plays a role in mechan ical retention of the sealant, the higher percen tage of retention reported by Buonocore might be explained by his careful selection of teeth that had well-defined pits and fissures, or deep fos sae, or both. Similar criteria for tooth selection were not used in this study or the one by H oro witz and associates; all eligible teeth were treat
lary second molars (bottom) at 3, 6, 12, and 24 months.
results for loss of substance and retention. Again, linear trends in time are generally appar ent, particularly after six months. A single dis crepancy in “ no loss” and “ slight loss” at three and six months for the distal pit area of mandib ular second premolars (Fig 4, top) points out the somewhat subjective nature of the rating scale used. ■ P o ro sity, p eelin g, a n d ledging: The inci dence of minor imperfections in the sealant sub stance was noted at each evaluation period to identify potential trends that may help explain
Table 5 ■ Incidence of porosity, peeling, and ledging for incisors and posterior teeth. Sealant imperfection
24 mo
12 mo
6 mo
3 mo
Teeth examined
n1
N o.t
%
n
No.
%
n
No.
%
n
No.
%
Posterior Incisors
505 36
6 0
1 0*
459 30
6 0
1 0
463 32
23 0
5 0
384 22
17 0
4 0
Posterior Incisors
505 36
6 4
1 11
459 30
20 9
4 30
463 32
14 4
3 13
384 22
2 2
1 9
Posterior Incisors
505 36
9 0
2 0
459 30
5 0
1 0
463 32
80 15
17 47
384 22
103 11
27 50
Porosity Peeling Ledging
*n is the number of incisors or posterior teeth evaluated for sealant imperfections. i'No. is the number of imperfections found. iT h e percentages shown for incisors are based on a relatively small sample size, and, therefore, are not as useful as those for posterior teeth. 394 ■ JADA, Vol. 92, February 1976
ed regardless of occlusal anatomic features. Higher retention rates could, of course, be the result of other factors as well. F or example, Buonocore did not identify the types of teeth included in his study. If his selection of teeth in cluded predominantly second premolars rather than a near equal distribution of teeth, overall retention values would have been inflated on the basis of the superior retention of sealant demon strated by the premolars over the molars in all three of the more recent two-year studies. Using the retention rates found by Rock and by H oro witz and associates for each different type of tooth, but recalculating an overall retention rate based on the distribution of teeth (by tooth type) in the present study, the overall retention rates would have been 68% for the study by Horowitz and co-workers and 79% for the study by Rock. Thus the results of Horowitz and co-workers would match the results of this study even more closely. In a comparison only, of second premo lars, which composed 73% of the total teeth treat ed by Rock, retention results are in complete agreement; both studies reported 86% of the sec ond premolars fully sealed after two years. Fur ther examination of the present study points out that overall retention results for paired permanent teeth would have been higher at all time periods if retention on the maxillary second molars had been better (sealant judged all present in only 14% at 24 months). Exclusion of these teeth at 24 months would have increased overall retention results to a 75% level. Considering the ages of the children included in this study and the erup tion pattern of the maxillary second molars, it becomes apparent that some correlation must exist between eruption pattern and poor reten tion of the sealant. Although cotton rolls and saliva ejectors were used for isolation, it can be conjectured that the occlusal surfaces were not completely dry. Considering that other teeth were more completely erupted, better isolated, and free of an imposing distal flap of tissue that undoubtedly contaminated the etched enamel surface, poor retention of the sealant in the max illary second molars should have been expected. Other tooth regions with similar but less drama tic retention results related to eruption and iso lation problems were the distal pit region of man dibular second molars and the mesial pit region of mandibular first premolars. Future efforts related to these specific teeth in patients 10 to 14 years of age might well exclude them from sealant application until the teeth have fully erupted, or the clinician must place the rubber
dam to ensure proper isolation during enamel sur face preparation and polymerization of the seal ant. Quantifying the data related to certain aspects of this study, such as loss of sealant substance, was made more difficult by the subjective nature of the rating scales used to assess the results. Sealant retention, for example, was easier to judge visually than loss of substance, since the latter required judgments based on gradual chang es rather than by the more perceptible gross change associated with no retention. The red dye in the sealant not only made qualitative judg ments related to substance loss possible, but also retention, porosity, peeling, and ledging were made easier to assess. Visible color changes from the dark red associated with newly applied, thick amounts of sealant, to the thinner and lighter pink sealant found after time and service in the mouth were an important factor in making deci sions related to substance loss. When the enamel was no longer masked by a pink film and the seal ant coating could no longer be discerned tactilely with the explorer tyne, the sealant was consid ered missing, even though visually imperceptible tags of sealant probably remained in the enamel pores created by the phosphoric acid etchant. The use of transparent Nuva-Seal would have required more tactile than visual perception, a factor that would have made judgments related to loss of substance nearly impossible. The use of a three-point rating scale to assess loss of retention and sealant substance, rather than the four-point scale that was used, would have greatly simplified the evaluation task and probably would have improved the reliability of the data as well. Slight loss of substance, which received a “ b” rating, was difficult to differen tiate from the no loss (“ a ” ) and the severe loss (“ c ” ) categories. Thus, “ b” ratings should be eliminated in future studies in favor of a simpler three-point scale, differentiating no apparent loss of substance from apparent loss and total loss (no retention). The linear trends that appear to be indicated in portions of the time plots for retention and loss of substance are important, since they provide a convenient summary of the data (particularly 6 through 24 months). They also may be useful in predicting results for other studies and for ex tended time periods. W hether such linear trends will be corroborated by 36-month results re mains to be determined. The results of the present two-year study sug gest that the most prudent time to inspect the G oing— others: CLINICAL EVALUATION OF A SEALANT ■ 395
sealant and repair defects or deficiencies is at 6-month intervals. If rubber dam isolation is not used during the initial application of the sealant, problem regions such as the distal pit of the max illary second molars may show the sealant partly missing at least 50% of the time for children in this age group. Although the study design and the frequency of occurrence do not permit the establishment of a cause-and-effect relationship between minor imperfections of sealant sub stance like peeling or ledging and loss of reten tion, it does suggest that these factors are pres ent and could become more significant after six months. This is exemplified by the increased amount of ledging that was recorded at the 12and 24-month evaluations. A study designed to evaluate these factors as they relate to micro leakage and initiation of caries after the reten tive seal is partially or totally lost should pro vide better insight into the life and longevity of the sealant material.
Sum m ary
For the study, 499 paired teeth (mostly perm anent) in 84 children were coated with NuvaSeal to which a red dye had been added to assist in placement and subsequent evaluation over a two-year period. Retention and loss of sealant substance were evaluated for all pit areas and rated on a four-point scale ranging from no loss of substance to no retention of the sealant. Nuva-Seal was fully retained on 92% of all paired, permanent teeth at 3 months, on 86% at 6 months, on 81% at 12 months, and on 69% at 24 months. With the exception of the maxillary second molars, the sealant was retained well on all molars, premolars, and lingual surfaces of maxillary incisors. For all four periods, retention of sealant on premolars was found to be superior to that on molars, retention on second premolars was superior to that on first premolars, and re tention on first molars was superior to that on second molars. Twenty-three of the 24 pit regions evaluated at 24 months showed predominantly severe or slight loss of substance compared with predom inantly slight or no loss of substance at 3 months. The three pit regions that showed the poorest retention of the sealant at 24 months were the distal pits of the maxillary and mandibular sec ond molars, and the mesial pit of the maxillary first molars. The three pit areas of mandibular 396 ■ JADA, Vol. 92, February 1976
second premolars showed collectively the best retention after 24 months of service.
The informed consents of all human subjects who participated in the experimental investigations reported in this manuscript were obtained after the nature of the clinical procedures and possible discomforts and risks had been fully explained. The authors thank Drs. Bruce Bell, Parker Mahan, John Chellemi, Tom Fast, and Stanley Lotzkar for their clinical assistance in the initial treatment of the children included in this study. Dr. Going is professor and research coordinator of operative dentistry, Dr. Haugh was assistant professor of statistics (now at the University of Vermont), Dr. Grainger is professor and chair man of operative dentistry, and Dr. Conti is assistant professor of community dentistry, University of Florida, College of Den tistry, Gainesville, 32610. Address requests for reprints to Dr. Going. *L. D. Caulk Co., Milford, Del 19963. tLee Pharmaceuticals, South El Monte, Calif 91733. tKohnstamm Co., New York. 1. Hyatt, T.P. Prophylactic odontotomy. The cutting into the tooth for the prevention of disease. Dent Cosmos 65:234 March 1923. 2. Bodecker, C.F. Enamel fissure eradication. NY State Dent J 30:149 April 1964. 3. Bodecker, C.F. Dental caries immunization without filling. NY State Dent J 30:337 Oct 1964. 4. Miller, J. Clinical investigations in preventive dentistry. Br Dent J 91:92 Aug 21, 1951. 5. Klein, H., and Knutson, J.W. Studies on dental caries. XIII. Effect of ammoniacal silver nitrate on caries in first permanent molar. JADA 29:1420 Aug 1942. 6 . Ast, D.B.; Bushel, A.; and Chase, H.C. Clinical study of caries prophylaxis with zinc chloride and potassium ferrocyanide. JADA 41:437 Oct 1950. 7. Gwinnett, A.J. Caries prevention through sealing of pits and fissures. J Can Dent Assoc 37:458 Dec 1971. 8 . Muhler, J.C., and others. Effect of a stannous fluoride-con taining dentifrice on caries reduction in children. J Dent Res 33: 606 Oct 1954. 9. Marthaler, T.M., and Schenardi, C. Inhibition of caries in children after 5V2 years' use of fluoridated table salt. Helv Odontol Acta 6:1 April 1962. 10. Marthaler, T.M. The value in caries prevention of other methods of increasing fluoride ingestion, apart from fluoridated water. Int Dent J 17:606 Sept 1967. 11. Marthaler, T.M. Caries-inhibiting effect of fluoride tablets. Helv Odontol Acta 13:1 April 1969. 12. Englander, H.R., and others. Residual anticaries effect of repeated topical sodium fluoride applications by mouthpieces. JADA 78:783 April 1969. 13. Peterson, J.K., and others. Effectiveness of an acidulated phosphate fluoride-pumice prophylactic paste: a two-year report. J Dent Res 48:346 May-June 1969. 14. Ast, D.B., and others. Newburg H-Kingston caries-fluorine study. XIV. Combined clinical and roentgenographic dental find ings after ten years of fluoride experience. JADA 52:314 March 1956. 15. Cueto, E.I., and Buonocore, M.G. Sealing of pits and fis sures with an adhesive resin: its use in caries prevention. JADA 75:121 July 1967. 16. Council on Dental Materials and Devices. Pit and fissure sealants. JADA 88:390 Feb 1974. 17. Buonocore, M. Adhesive sealing of pits and fissures for caries prevention, with use of ultraviolet light. JADA 80:324 Feb 1970.
18. Buonocore, M.G. Caries prevention in pits and fissures sealed with an adhesive resin polymerized by ultraviolet light: a two-year study of a single adhesive application. JADA 82:1090 May 1971. 19. Rock, W.P. Fissure sealants. Results obtained with two different sealants after one year. Br Dent J 133:146 Aug 15, 1972. 20. Rock, W.P. Fissure sealants. Results obtained with two different bis-GMA type sealants after one year. Br Dent J 134:193 March 6, 1973. 21. McCune, R.J., and others. Pit and fissure sealants: one-year results from a study in Kalispell, Montana. JADA 87:1177 Nov 1973.
22. Rock, W.P. Fissure sealants. Further results of clinical trials. Br Dent J 136:317 April 16, 1974. 23. Horowitz, H.S.; Heifetz, S.B.; and McCune, R.J. The effec tiveness of an adhesive sealant in preventing occlusal caries: findings after two years in Kalispell, Montana. JADA 89:885 Oct 1974. 24. De Paola, P.F. The interpretation of findings in clinical caries trials. J Dent Child 4 1 :11 Jan-Feb 1974. 25. Mainland, D.; Herrera, L.; and Sutcliffe, M. Tables for use with binomial samples. NY University College of Medicine, 1956.
Foley’s Footnotes Perhaps the most valuable o f the few dental autobiographies is William G uy’s Mostly Memories—Some Digressions (1948). G uy received diplomas in both medicine and dentistry. A fter practicing medicine fo r several years he studied at the Edinburgh Dental Hospital and School, 1890-1892. A man o f versatile capa bility, he contributed richly to the interests o f British dentistry and dental educa tion as a progressive member o f the British Dental Association (president, 1914) and as dean o f his alma mater. William Guy became well known internationally because o f his pioneer and continuing efforts in the promotion o f the Federation Dentaire Internationale. In this footnote I shall give attention only to Guy’s recollections of his experiences as a student at the Edinburgh Dental Hospital and Dental School. They form an interesting and provocative commentary on many aspects of the program offered by the Edinburgh School in the early 1890s. I attended the Dental Hospital daily from 9 a.m. till noon. The afternoon I spent in the workroom at No. 11. The Dental Lectures were given either at 8 a.m. or 8 p.m. on two days o f the week. At the Dental Hospital there was one house surgeon dentist and an honorary staff, two of whom were supposed to be on duty on their appointed day of the week. In fact, the students were left very much to their own devices, with little direction from the staff. I found myself providing my own patients and materials. Gold stopping was all the rage; proficiency in this procedure was the only thing that counted in the assessment of operative skill. Gas (N2O) was administered from an antiquated apparatus. When the patient was black in the face, the anaesthetist removed the mask. Jactitation and struggling accompanied this semi-asphyxiation and impeded the operator, who sometimes took the precautionary measure of strapping his patient to the chair. Gas was used when one or two easy teeth were to be extracted, for greater numbers Chloroform was required. If a mouth was to be cleared, the necessary forceps (10 to 12) were laid on the table, and much time was consumed in changing instruments. The rubber dam was used for the exclusion of saliva in tooth filling, but unhappily saliva ejectors were not provided; the consequent dribbling often left the patients as drenched as if they had been out in the rain. There was a gold-filling competition. As there was no system for inspecting fillings and allotting marks, the Medal went to the man who had done the biggest number. One man who won it did fifteen in a sitting. Of course, they were just pinhead fillings and ought not to have been counted. I attended the lectures but was not greatly edified. None of the usual helpful items of equipment were provided by the School. I soon perceived that the whole set-up was just a makeshift. The prem ises were unsuitable, the equipment inadequate, the teaching amateurish and insufficient. The stu dents were thrown on their own resources. For want of direction and demonstration, difficulties were solved by the process of trial and error, which involved useless expenditure of time and effort. Not that the individual student was distressed or discouraged: self-help made himself-reliant. And after all, the necessary knowledge could be garnered from the printed page. Gardner P. H. Foley
G oing—others: CLINICAL EVALUATION OF A SEALANT ■ 397
Two-year clinical evaluation of a pit and fissure sealant. Part I: Retention and loss of substance
Robert E. Going, DDS, MS Larry D. Haugh, PhD David A. G rainger, DDS Anthony J. Conti, DMD, MPH, Gainesville, Fla
A pit and fissure sealant was applied to the teeth of children between 10 and 14 years of age to evaluate the retention and loss of sealant substance over a two-year period. The sealant was fully retained on 92% of all paired, permanent teeth at 3 months, on 86% at 6 months, 81 % at 12 months, and 69% at 24 months. Twenty-three of 24 occlusal pit regions evaluated at 24 months showed a predominance of substance loss ranging from slight to severe, with the latter more prevalent. The single exception was the distal pit of the maxillary second molar, which showed no retention of the sealant in 83% of the teeth.
388 ■ JADA, Vol. 92, February 1976
Preventing caries from developing in the pits and fissures of teeth has been of practical impor tance for some time and has generated an exten sive search for methods and materials that might control the occlusal caries problem .1' 14 Recent attempts to seal and protect pits and fissures from caries use organic polymers that adhere to the enamel adjacent to pit and fissure defects. The first comprehensive report of sealing the highly susceptible pits and fissures of teeth with an adhesive resin was published in 1967.15 Sub sequent clinical trials using sealants based on the reaction product of bisphenol A and glycidyl methacrylate (BIS-GMA) have used different mixtures of the base polymers, different applica tion techniques, and different curing methods. Nuva-Seal* and Epoxylite Fissure Sealant 9075t have been used in clinical applications and have received recognition as agents for restoring or sealing off anatomically deficient surfaces of teeth .16 The purpose of this study was to evaluate more comprehensively the clinical retention and loss of substance of a single application of a pit and fissure sealant and to determine the influence this protective coating might have on caries ac tivity in teeth over a two-year period. Nuva-Seal was selected to be used in this study on the basis of its proven success in previous clinical stud ies.17'23 This paper reports the results related to the retention and loss of substance of the pit and fis
sure sealant. A subsequent paper (March j a d a ) will report on the caries-protective efficacy of the sealant after two years of clinical service.
M aterials and methods
Eighty-four children, ranging in age from 10 to 14 years, were chosen after preliminary examina tion from the fifth through eighth grades of a single school in a stable, integrated community of low-income families in the nonfluoridated rural area of Alachua, Fla. An approximately uniform distribution of children with respect to sex and race was used, with only four children in the 14-year-old age group. For the study, 479 sound, paired permanent teeth and 20 paired deciduous teeth were coated under controlled clinical conditions with a methacrylate-type polymer, Nuva-Seal, and poly merized by ultraviolet light (Nuva-Lite*). A red dye (F D & C no. 17 Redt) was added to the seal ant by the manufacturer to assist in visualizing the placement and subsequent evaluation of the sealant’s retention and loss of substance. A half mouth technique was used; one side of the mouth of each patient was randomly selected for treatm ent, and the other served as the untreated control. The treated teeth and their contralateral controls were considered study pairs. Fifty-two unpaired teeth also were coated with Nuva-Seal, but were not included in most of the final analy ses. Baseline examination and treatment proce dures were completed in the dental clinic at the University of Florida College of Dentistry. All patients were routed through five stations, each staffed with a dentist and chairside assistant as signed to complete a specific function. Before the teeth were coated with sealant, each child received a prophylaxis at station 1 with a fluoride-free cleaning and polishing paste carried to the tooth surfaces with a rubber cup. The mouth was irrigated thoroughly to remove the cleansing agent, and the patient was directed to station 2 where a baseline examination was made with a dental mirror and sharp no. 23 ex plorer under dry, well-lighted conditions. The pits and fissures of each tooth were scored and recorded on a treatment and evaluation record according to a rating scale similar to that used by Buonocore.17 Numerals of 0 (caries free) to 4 (severe caries) were assigned, since not all teeth included in this study were caries free. In addi
tion, the location of all explorer catches (rating of 2), penetration of the explorer (rating of 3), and large carious lesions (rating of 4) were noted on an anatomic diagram of each tooth that appeared adjacent to the rating column. Mesial, central, and distal pit regions were differentiated for pos terior teeth; only the lingual pit region was noted for maxillary incisors. Conditioning of the teeth with the Nuva-System Tooth Conditioner* (50% phosphoric acid buffered with 7% zinc ox ide) and application and polymerization of the sealant were accomplished at either station 3 or 4. To maintain optimal dryness of the tooth sur faces after etching, washing, and application of compressed air, the dentist conditioning the teeth and the dentist applying the sealant were rotated between stations 3 and 4. The patient and the assigned dental assistant, on the other hand, remained stationary until both procedures were completed, following the instructions pro vided by the manufacturer. From the condition ing phase through the application and polymer ization of the sealant, the teeth to be treated were maintained in a dry state with use of cotton rolls and saliva ejectors. A t station 5 all treated teeth were scrutinized for correct application of the sealant, and records were checked for accur acy and completeness. Evaluation of the treated and control teeth for each patient was done at intervals of 3, 6, 12, and 24 months by two independent examiners at the grade school in Alachua. Rating disagreements between examiners were resolved during a joint examination before the patient was dismissed. New evaluation forms were used at each time interval to prevent the examiners from being biased by previous ratings. The use of portable dental equipment in a simulated clinical environ ment permitted sufficient flexibility to retain in the study a small number of children who trans ferred to other schools in the same county. Retention and loss of sealant substance for each pit region was evaluated by visual inspec tion and dental explorer and rated on a four-point scale, “ a” through “ d .” N o apparent loss of sub stance received an “ a” rating, slight loss of sub stance a “ b” rating, severe loss of substance a “ c” rating, and total loss of substance (no reten tion) a “ d ” rating. Although “ a ,” “ b ,” and “ c” ratings indicated retention of the material, more specifically they rated the amount of substance lost. Therefore, each tooth was scored as having the sealant missing when all pit regions were rat ed “ d ,” sealant partly missing when at least one pit region was rated “ d ,” and sealant present G oing— others: CLINICAL EVALUATION OF A SEALANT ■ 389
Table 1 ■ N u m b e r o f i n i t i a l l y s o u n d p a i r e d a n d u n p a i r e d t e e t h a v a il a b le a t v a r i o u s c l i n i c a l e x a m i n a t i o n s .
Examination Baseline 3 mo 6 mo 12 mo 24 mo
No. children 84 83 77 79 70
T reated/ control pairs 479 475 448 454 404
(20)’ (16) (8) (9) (4)
T reated unpaired 39 37 32 39 31
(13) (15) (7) (6) (2)
C ontrol unpaired 37 37 35 37 32
(9) (7) (2) (4) (1)
Treated total 518 512 480 493 435
(33) (31) (15) (15) (6)
C ontrol total 516 512 483 491 436
(29) (23) (10) (13) (5)
'P rim ary teeth in parentheses; perm anent teeth w ith o u t parentheses.
when each pit region remained coated and rated with either an “ a ,” “ b ,” or “ c .” Teeth with transverse ridges were not evaluated in the cen tral pit region. Porosity, peeling, and ledging of the sealant material also were evaluated. Surface porosity was evident as small holes on the surface of the sealant material. When present, it was demon strated best by visual inspection and an explorer tyne carried lightly across the polymerized sur face. Peeling and ledging were discerned both visually and by explorer at the junction of the polymerized sealant and the enamel surface. Peeling was defined as a loosening and slight lift ing of the edges of the sealant from the enamel. Ledging was defined as loss of the peeled edge, leaving a slightly elevated, firm, steplike margin of sealant.
R esults
The number of children available for examina tion at the 3-, 6-, 12-, and 24-month time inter vals was 83, 77, 79, and 70 respectively. Thus, after two years, 83% of the original children re mained in the study. Of the 16 children unavail able at one or more examinations, there were more white children missing than black children (12 versus 4) and more 12 year olds (7) than chil dren in any other single age group. No impor tant bias was evident as a result of these factors. The number of initially sound paired and un paired teeth available for all examinations is pre sented in Table 1. The median number of study pairs per child at the baseline examination was six, with 81% of the children having between four and eight pairs available for sealant applica tion. After one year, 95% of the paired perma nent teeth were available for examination, and after two years 84%. In the analysis of data on sealant retention and loss of substance, the various time intervals (four examinations), number of different teeth (eight to ten), anatomic regions of the occlusal surface 390 ■ JADA, Vol. 92, February 1976
(one to three pit regions), and substance loss (four-point scale) were related one to another. For example, plots of retention rates against time permitted evaluation of how quickly sealant ad herence dropped in time, and certain composite bar graphs permitted comparisons between dif ferent teeth or anatomic regions for the data deal ing with loss of substance. ■ S ea la n t retention: Nuva-Seal was completely retained on 92% of all paired, permanent teeth at 3 months, 86% at 6 months, 81% at 12 months, and 69% at 24 months (Fig 1 and Tables 2 and 3). The proportion of teeth losing all sealant was only 1% from the baseline examination to 6 months of service, 2% at 12 months, and 8% at 24 months. Figure 1 indicates a relatively sharp decrease in retention for the period up to six months, but a linear trend for the time per iods beyond six months. The slope of this linear trend indicates that approximately 1% of the teeth were losing part or all of their sealant per month. With the exception of the maxillary second molars, the sealant was retained well on all mo lars, premolars, and lingual surfaces of maxilSEALANT
□ ES
T IM E
MISSING
SEALANT PARTLY MISSING S E ALAN T
PRESENT
P E R IO D (M O N T H S )
Fig 1 ■ Sealant retention on paired perm anent teeth at 3, 6, 12, and 24 m onths.
Table 2 ■ Sealant retention on paired permanent teeth at 12 months. Sealant all missing
Sealant partly missing
Sealant all present
Teeth examined
No.
No.
%
No.
%
No.
%
95% Cl*
All teeth All maxillary teeth All mandibular teeth All molars All premolars Maxillary first premolars Mandibular first premolars Maxillary second premolars Mandibular second premolars Maxillary first molars Mandibular first molars Maxillary second molars Mandibular second molars Maxillary incisors
454 241 213 170 253 64 70 59 60 47 49 40 34 31
11 6 5 5 5 1 4 0 0 1 0 3 1 1
2.4 2.5 2.3 2.9 2.0 1.6 5.7 0.0 0.0 2.1 0.0 7.5 2.9 3.2
76 43 33 51 23 2 12 3 6 12 8 24 7 2
16.7 17.8 15.5 30.0 9.1 3.1 17.1 5.1 10.0 25.5 16.3 60.0 20.6 6.5
367 192 175 114 225 61 54 56 54 34 41 13 26 28
80.8 79.7 82.2 67.1 88.9 95.3 77.1 94.9 90.0 72.3 83.7 32.5 76.5 90.3
(77-84) (75-85) (76-87) (59-74) (85-93) (86-99) (65-86) (86-99) (80-96) (57-84) (71-93) (11-41) (59-89) (74-98)
*95% confidence intervals derived from published tables.25
Table 3 ■ Sealant retention on paired permanent teeth at 24 months. Sealant all missing
Sealant partly missing
Sealant all ______ present
Teeth examined
No.
No.
%
No.
%
No.
%
95% c r
All teeth All maxillary teeth All mandibular teeth All molars All premolars Maxillary first premolars Mandibular first premolars Maxillary second premolars Mandibular second premolars Maxillary first molars Madibular first molars Maxillary second molars Mandibular second molars Maxillary incisors
404 217 187 152 225 59 60 53 53 42 44 36 30 27
33 22 11 14 14 3 7 4 0 3 2 7 2 5
8.2 10.1 5.9 9.2 6.2 5.1 11.7 7.5 0.0 7.1 4.5 19.4 6.7 18.5
91 53 38 67 22 6 5 3 8 18 13 24 12 2
22.5 24.4 20.3 44.1 9.8 10.2 8.3 5.7 15.1 42.9 29.5 66.7 40.0 7.4
280 142 138 71 189 50 48 46 45 21 29 5 16 20
69.3 65.4 73.8 46.7 84.0 84.7 80.0 86.8 84.9 50.0 65.9 13.9 53.3 74.1
(65-74) (59-72) (67-80) (39-55) (79-89) (73-93) (68-89) (75-95) (73-93) (34-66) (50-80) ( 5-29) (34-72) (54-89)
*95% confidence interval using normal approximation to the binomial distribution, except when approximation is poor.
lary incisors through 12 months. The sealant was totally present on all tooth types at least at an 87% retention level at three months and a 79% level at six months, compared with only a 61% and a 40% retention level respectively, for the maxillary second molars (data not shown). A further decrease in complete retention to 33% and 14% was found for the maxillary second mo lars at 12 and 24 months, whereas all other types of teeth showed retention generally above 72% and 50% for these same time periods. Retention of sealant on premolars was found superior to retention on molars for all time per iods, with 84% of the premolars remaining com pletely sealed up to 24 months compared with only 47% of the molars. A t all four evaluation periods, the retention of sealant on second pre molars was superior to retention on first pre molars, and retention on first molars was always superior to that on second molars. Also, sealant retention in the mandibular arch was slightly superior, in general, to that in the maxillary arch. F or example, at 24 months, 74% of the mandib ular teeth had sealant all present compared with 65% for those in the maxillary arch. Since estimates of retention rates are based on
those children selected for the study, it is useful to calculate confidence intervals for retention rates as an expression of the uncertainty that necessarily exists in attempting to select a truly representative group of children.24 The intervals given in Tables 2 and 3 are 95% certain to con tain the true complete retention rates for all sim ilar children. Figure 2 illustrates how sealant retention rates for premolars and molars decrease with time. The retention rates are percentages of those teeth available for examination at each time per iod. As in Figure 1, a linear trend is generally evident between time periods, especially after six months. This trend depends on tooth type; for example, the molars show greater rates of decline than do the premolars. The small, ap parent increase in retention from 12 to 24 months for mandibular first premolars is probably the re sult of either the small differences in the number of children involved or slight judgmental differ ences in assessing retention at each time period. Sealant retention for the unpaired permanent teeth was generally not as good as that found for paired permanent teeth. A more detailed com parison is of little value, however, since only 31 G oing— others: CLINICAL EVALUATION OF A SEALANT ■ 391
tia I
SEALANT M IS SIN G 1 SEALANT PARTLY MISSING
[ 3
3
6
UPPER
12 24 FIRST
PREMOLARS
3
6
12
24
SEALANT
3
LOWER FIRST PREMOLARS
6
12
PRESENT
24
3
6
LOWER SECOND
PREMOLARS
PREMOLARS
100 8070 605040
W M
■É
90-
t
3020
I o-
0 3
6
12 24
UPPER F IR S T MOLARS
iI 6
12 24
LOWER FIR S T MO LARS
T IM E
3
12 2 4
UPPER SECOND
6
12
24
UPPER SECOND MOLARS
6
12 24
LOWER SECOND MOLARS
PERIOD (MONTHS)
Fig 2 ■ Sealant retention on paired prem olars (top) and perm anent molars (bottom ) at 3, 6, 12, and 24 months.
treated, unpaired teeth were available for exam ination at 24 months. Similarly, no useful com parisons could be made for the deciduous teeth. The retention experience of those patients missing certain examinations was not significant ly different from those who were present. For example, the nine patients who were lost from the study between the 12- and 24-month exam ination periods had retention rates at 12 months that were comparable to those of patients who continued to 24 months. ■ L o ss o f su b sta n ce a n d retention by an atom ic region: Loss of sealant substance and retention were evaluated for the mesial, central, and distal pit regions of posterior teeth, as well as the lin gual pit region of maxillary incisors. 392 ■ JADA, Vol. 92, February 1976
At the three-month examination, substance loss was visually and functionally apparent in most pit regions. This result was anticipated, since no children complained of hyperocclusion on the treated side, a factor that was present at initial placement. The mesial pit region of all molars and premolars, in general, showed a greater extent of severe loss of substance than either the central or distal pit regions, and the severe loss was more noticeable in molars than in premolars (Fig 3). Figure 3, top, also shows that the maxillary first molars had the greatest frequency of severe loss of substance in the me sial pit region (92%), yet the sealant was com pletely missing from this area (no retention) in only 6% of the children. To summarize loss of substance by anatomic region at three months, the three pit regions for all posterior teeth except one type showed dis cernible differences in rates of substance loss. The single exception was the mandibular second premolars, which received nearly the same dis tribution of loss of substance ratings in all three pit regions at three months. The three pit regions that showed the poorest retention of the sealant at three months were the distal pits of the maxil lary and mandibular second molars and the me sial pit of the mandibular first premolars (37%, 9%, and 12% no retention, respectively). At 24 months the degree of substance loss was substantially increased over that found at 3 months. The percentage of “ no loss of sub stance” ratings never exceeded 10% in any of the 24 anatomic regions evaluated (Table 4), whereas at three months the comparable statistic was 51% (compare Fig 3, top and bottom). The initial loss of substance from the baseline exam ination to 3 months was significant, and the fur ther reduction at 24 months indicates continued substance loss. The relative differences in substance loss be tween the mesial, central, and distal pit regions decreased at 24 months (Fig 3, bottom). In con trast to the pattern at three months, no one re gion was uniformly better for all teeth. Twentythree of the 24 anatomic areas showed substance loss ranging predominantly from slight to severe, with the latter now more prevalent than at three months (compare Fig 3, top and bottom). The single exception was the distal pit of the max illary second molars where “ no retention” of the sealant was predominant. At 24 months, the three pit areas that showed the poorest reten tion of the sealant were the distal pits of the max illary and mandibular second molars and the
i ü
o * NO LOSS OF SUBSTANCE
I
I
b = SLIGHT LOSS OF SUBSTANCE C - SEVERE LOSS OF SUBSTANCE d * NO RETENTION
M C UPPER F IR S T PREMOLARS
AREA:
LOWER F IR ST PREMOLARS
UPPER SECOND PREMOLARS
M - MESIAL PIT AREA
C - CENTRAL
M C
D
PIT AREA
D
UPPER SECOND MOLARS
LOWER. FIR ST MOLARS
LOWER SECOND PREMOLARS
D - D IS T A L P I T
AREA
JOO
Fig 3 ■ Loss of substance and retention by anatomic region for paired permanent teeth at 3 months (top) and at 24 months (bottom).
UPPER FIRST PREMOLARS
AREA
LOWER FIRST PREMOLARS
UPPER SECOND PREMOLARS
M - MESIAL PIT AREA
LOWER SECOND PREMOLARS
UPPER FIRST MOLARS
C - CENTRAL PIT AREA
D " DISTAL PIT AREA
Table 4 ■ Loss of substance and retention by anatomic region on paired permanent teeth at 24 months.* Mesial pit regionf Tooth type
No.
Maxillary first premolar Mandibular first premolarf Maxillary second premolar Mandibular second premolar§ Maxillary first molar Mandibular first molar Maxillary second molar Mandibular second molar
59 60 53 53
a 0.0 0.0 0.0 1.9
42 44 36 30
0.0 0.0 0.0 0.0
b 10.2 20.0 3.8 13.2
c 78.0 65.0 86.8 79.3
0.0 0.0 2.8 3.3
57.1 84.1 66.7 76.7
Central pit region d
Distal pit region
b
c
d
11.9 15.0 9.4 5.6
a 0.0 0.0 0.0 2.0
11.9 7.1 22.6 7.8
81.4 67.9 67.9 84.3
42.9 15.9 30.6 20.0
0.0 0.0 5.6 10.0
9.5 15.9 41.7 30.0
71.4 75.0 27.8 50.0
b
6.8 25.0 9.4 5.9
a 0.0 0.0 0.0 3.8
28.8 43.4 15.1 43.4
c 62.7 41.7 73.6 43.4
8.5 15.0 11.3 9.4
d
19.0 9.1 25.0 10.0
?,4 00 8.3 3.3
28.6 6.8 8.3 6.7
50.0 70.5 0.0 46.7
19.0 22.7 83.3 43.3
'Figures reported are percentages of teeth having the specified substance loss in a particular region, fa, no loss of substance; b, slight loss of substance; c, severe loss of substance; d, no retention. ^Number o f central p it regions evaluated is 28. ¿Number of central pit regions evaluated is 51.
mesial pit of the maxillary first molars (83%, 43%, and 43% “ no retention,” respectively). The mandibular second premolars showed the best collective retention in their three pit regions, with only 6%, 6%, and 9% “ no retention,” re
spectively. The temporal patterns of sealant loss by ana tomic regions for mandibular second premolars and maxillary second molars are presented in Figure 4, thus exemplifying the best and worst G oing— others: CLINICAL EVALUATION OF A SEALANT ■ 393
u ro a
a " no U3ss o f substanc e
C3
b»SLIGHT LOSS OF SUBSTANCE
the retention and loss of substance results (Table
5).
C* SEVERE LOSS OF SUBSTANCE KKR3 d«NO RETENTION
3
6
12
24
3
6
MESIAL PIT AREA
T IM E
3
6
12
12
24
3
6
CENTRAL PIT AREA
24
MESIAL PIT AREA
3
. 24
DISTAL PIT AREA
P E R IO D (M O N T H S )
6
12
24
3
CENTRAL PIT AREA T IM E
12
F or posterior teeth, porosity in the sealant reached a peak incidence of 5% after 12 months. Peeling reached a peak of 4% at six months and declined thereafter, whereas ledging was noted more frequently after one year (17%) and con tinued to a high of 27% after 24 months. For inci sors, porosity was not noted in the approxi mately 30 teeth evaluated, and peeling and ledg ing followed a pattern similar to that found on posterior teeth, but at a higher level. In an attempt to check possible connections between peeling and either ledging or sealant loss, the 28 teeth that demonstrated peeling of the sealant at either the 3- or 6-month examina tions (and not missing at 24 months) were more carefully scrutinized. Twelve (43%) showed evi dence of ledging by 24 months and only ten (36%) had completely lost the sealant. Of the remaining six teeth, five appeared normal at the latter ex amination and one continued to show peeling.
PE RIO D
6
12
24
DISTAL PIT AREA
(M O N T H S )
Discussion Fig 4 ■ Loss of substance and retention by anatomic region for paired mandibular second premolars (top) and permanent maxil
The two-year retention results reported in this study corroborate the essential findings of Buonocore,18 Rock,22 and Horowitz and co-workers.23 After two years of clinical use, Buonocore re ported the teeth to be fully sealed at an 87% level; Rock reported an 80% level; Horowitz, a 73% level; and this study, a 69% level. Because surface morphology apparently plays a role in mechan ical retention of the sealant, the higher percen tage of retention reported by Buonocore might be explained by his careful selection of teeth that had well-defined pits and fissures, or deep fos sae, or both. Similar criteria for tooth selection were not used in this study or the one by H oro witz and associates; all eligible teeth were treat
lary second molars (bottom) at 3, 6, 12, and 24 months.
results for loss of substance and retention. Again, linear trends in time are generally appar ent, particularly after six months. A single dis crepancy in “ no loss” and “ slight loss” at three and six months for the distal pit area of mandib ular second premolars (Fig 4, top) points out the somewhat subjective nature of the rating scale used. ■ P o ro sity, p eelin g, a n d ledging: The inci dence of minor imperfections in the sealant sub stance was noted at each evaluation period to identify potential trends that may help explain
Table 5 ■ Incidence of porosity, peeling, and ledging for incisors and posterior teeth. Sealant imperfection
24 mo
12 mo
6 mo
3 mo
Teeth examined
n1
N o.t
%
n
No.
%
n
No.
%
n
No.
%
Posterior Incisors
505 36
6 0
1 0*
459 30
6 0
1 0
463 32
23 0
5 0
384 22
17 0
4 0
Posterior Incisors
505 36
6 4
1 11
459 30
20 9
4 30
463 32
14 4
3 13
384 22
2 2
1 9
Posterior Incisors
505 36
9 0
2 0
459 30
5 0
1 0
463 32
80 15
17 47
384 22
103 11
27 50
Porosity Peeling Ledging
*n is the number of incisors or posterior teeth evaluated for sealant imperfections. i'No. is the number of imperfections found. iT h e percentages shown for incisors are based on a relatively small sample size, and, therefore, are not as useful as those for posterior teeth. 394 ■ JADA, Vol. 92, February 1976
ed regardless of occlusal anatomic features. Higher retention rates could, of course, be the result of other factors as well. F or example, Buonocore did not identify the types of teeth included in his study. If his selection of teeth in cluded predominantly second premolars rather than a near equal distribution of teeth, overall retention values would have been inflated on the basis of the superior retention of sealant demon strated by the premolars over the molars in all three of the more recent two-year studies. Using the retention rates found by Rock and by H oro witz and associates for each different type of tooth, but recalculating an overall retention rate based on the distribution of teeth (by tooth type) in the present study, the overall retention rates would have been 68% for the study by Horowitz and co-workers and 79% for the study by Rock. Thus the results of Horowitz and co-workers would match the results of this study even more closely. In a comparison only, of second premo lars, which composed 73% of the total teeth treat ed by Rock, retention results are in complete agreement; both studies reported 86% of the sec ond premolars fully sealed after two years. Fur ther examination of the present study points out that overall retention results for paired permanent teeth would have been higher at all time periods if retention on the maxillary second molars had been better (sealant judged all present in only 14% at 24 months). Exclusion of these teeth at 24 months would have increased overall retention results to a 75% level. Considering the ages of the children included in this study and the erup tion pattern of the maxillary second molars, it becomes apparent that some correlation must exist between eruption pattern and poor reten tion of the sealant. Although cotton rolls and saliva ejectors were used for isolation, it can be conjectured that the occlusal surfaces were not completely dry. Considering that other teeth were more completely erupted, better isolated, and free of an imposing distal flap of tissue that undoubtedly contaminated the etched enamel surface, poor retention of the sealant in the max illary second molars should have been expected. Other tooth regions with similar but less drama tic retention results related to eruption and iso lation problems were the distal pit region of man dibular second molars and the mesial pit region of mandibular first premolars. Future efforts related to these specific teeth in patients 10 to 14 years of age might well exclude them from sealant application until the teeth have fully erupted, or the clinician must place the rubber
dam to ensure proper isolation during enamel sur face preparation and polymerization of the seal ant. Quantifying the data related to certain aspects of this study, such as loss of sealant substance, was made more difficult by the subjective nature of the rating scales used to assess the results. Sealant retention, for example, was easier to judge visually than loss of substance, since the latter required judgments based on gradual chang es rather than by the more perceptible gross change associated with no retention. The red dye in the sealant not only made qualitative judg ments related to substance loss possible, but also retention, porosity, peeling, and ledging were made easier to assess. Visible color changes from the dark red associated with newly applied, thick amounts of sealant, to the thinner and lighter pink sealant found after time and service in the mouth were an important factor in making deci sions related to substance loss. When the enamel was no longer masked by a pink film and the seal ant coating could no longer be discerned tactilely with the explorer tyne, the sealant was consid ered missing, even though visually imperceptible tags of sealant probably remained in the enamel pores created by the phosphoric acid etchant. The use of transparent Nuva-Seal would have required more tactile than visual perception, a factor that would have made judgments related to loss of substance nearly impossible. The use of a three-point rating scale to assess loss of retention and sealant substance, rather than the four-point scale that was used, would have greatly simplified the evaluation task and probably would have improved the reliability of the data as well. Slight loss of substance, which received a “ b” rating, was difficult to differen tiate from the no loss (“ a ” ) and the severe loss (“ c ” ) categories. Thus, “ b” ratings should be eliminated in future studies in favor of a simpler three-point scale, differentiating no apparent loss of substance from apparent loss and total loss (no retention). The linear trends that appear to be indicated in portions of the time plots for retention and loss of substance are important, since they provide a convenient summary of the data (particularly 6 through 24 months). They also may be useful in predicting results for other studies and for ex tended time periods. W hether such linear trends will be corroborated by 36-month results re mains to be determined. The results of the present two-year study sug gest that the most prudent time to inspect the G oing— others: CLINICAL EVALUATION OF A SEALANT ■ 395
sealant and repair defects or deficiencies is at 6-month intervals. If rubber dam isolation is not used during the initial application of the sealant, problem regions such as the distal pit of the max illary second molars may show the sealant partly missing at least 50% of the time for children in this age group. Although the study design and the frequency of occurrence do not permit the establishment of a cause-and-effect relationship between minor imperfections of sealant sub stance like peeling or ledging and loss of reten tion, it does suggest that these factors are pres ent and could become more significant after six months. This is exemplified by the increased amount of ledging that was recorded at the 12and 24-month evaluations. A study designed to evaluate these factors as they relate to micro leakage and initiation of caries after the reten tive seal is partially or totally lost should pro vide better insight into the life and longevity of the sealant material.
Sum m ary
For the study, 499 paired teeth (mostly perm anent) in 84 children were coated with NuvaSeal to which a red dye had been added to assist in placement and subsequent evaluation over a two-year period. Retention and loss of sealant substance were evaluated for all pit areas and rated on a four-point scale ranging from no loss of substance to no retention of the sealant. Nuva-Seal was fully retained on 92% of all paired, permanent teeth at 3 months, on 86% at 6 months, on 81% at 12 months, and on 69% at 24 months. With the exception of the maxillary second molars, the sealant was retained well on all molars, premolars, and lingual surfaces of maxillary incisors. For all four periods, retention of sealant on premolars was found to be superior to that on molars, retention on second premolars was superior to that on first premolars, and re tention on first molars was superior to that on second molars. Twenty-three of the 24 pit regions evaluated at 24 months showed predominantly severe or slight loss of substance compared with predom inantly slight or no loss of substance at 3 months. The three pit regions that showed the poorest retention of the sealant at 24 months were the distal pits of the maxillary and mandibular sec ond molars, and the mesial pit of the maxillary first molars. The three pit areas of mandibular 396 ■ JADA, Vol. 92, February 1976
second premolars showed collectively the best retention after 24 months of service.
The informed consents of all human subjects who participated in the experimental investigations reported in this manuscript were obtained after the nature of the clinical procedures and possible discomforts and risks had been fully explained. The authors thank Drs. Bruce Bell, Parker Mahan, John Chellemi, Tom Fast, and Stanley Lotzkar for their clinical assistance in the initial treatment of the children included in this study. Dr. Going is professor and research coordinator of operative dentistry, Dr. Haugh was assistant professor of statistics (now at the University of Vermont), Dr. Grainger is professor and chair man of operative dentistry, and Dr. Conti is assistant professor of community dentistry, University of Florida, College of Den tistry, Gainesville, 32610. Address requests for reprints to Dr. Going. *L. D. Caulk Co., Milford, Del 19963. tLee Pharmaceuticals, South El Monte, Calif 91733. tKohnstamm Co., New York. 1. Hyatt, T.P. Prophylactic odontotomy. The cutting into the tooth for the prevention of disease. Dent Cosmos 65:234 March 1923. 2. Bodecker, C.F. Enamel fissure eradication. NY State Dent J 30:149 April 1964. 3. Bodecker, C.F. Dental caries immunization without filling. NY State Dent J 30:337 Oct 1964. 4. Miller, J. Clinical investigations in preventive dentistry. Br Dent J 91:92 Aug 21, 1951. 5. Klein, H., and Knutson, J.W. Studies on dental caries. XIII. Effect of ammoniacal silver nitrate on caries in first permanent molar. JADA 29:1420 Aug 1942. 6 . Ast, D.B.; Bushel, A.; and Chase, H.C. Clinical study of caries prophylaxis with zinc chloride and potassium ferrocyanide. JADA 41:437 Oct 1950. 7. Gwinnett, A.J. Caries prevention through sealing of pits and fissures. J Can Dent Assoc 37:458 Dec 1971. 8 . Muhler, J.C., and others. Effect of a stannous fluoride-con taining dentifrice on caries reduction in children. J Dent Res 33: 606 Oct 1954. 9. Marthaler, T.M., and Schenardi, C. Inhibition of caries in children after 5V2 years' use of fluoridated table salt. Helv Odontol Acta 6:1 April 1962. 10. Marthaler, T.M. The value in caries prevention of other methods of increasing fluoride ingestion, apart from fluoridated water. Int Dent J 17:606 Sept 1967. 11. Marthaler, T.M. Caries-inhibiting effect of fluoride tablets. Helv Odontol Acta 13:1 April 1969. 12. Englander, H.R., and others. Residual anticaries effect of repeated topical sodium fluoride applications by mouthpieces. JADA 78:783 April 1969. 13. Peterson, J.K., and others. Effectiveness of an acidulated phosphate fluoride-pumice prophylactic paste: a two-year report. J Dent Res 48:346 May-June 1969. 14. Ast, D.B., and others. Newburg H-Kingston caries-fluorine study. XIV. Combined clinical and roentgenographic dental find ings after ten years of fluoride experience. JADA 52:314 March 1956. 15. Cueto, E.I., and Buonocore, M.G. Sealing of pits and fis sures with an adhesive resin: its use in caries prevention. JADA 75:121 July 1967. 16. Council on Dental Materials and Devices. Pit and fissure sealants. JADA 88:390 Feb 1974. 17. Buonocore, M. Adhesive sealing of pits and fissures for caries prevention, with use of ultraviolet light. JADA 80:324 Feb 1970.
18. Buonocore, M.G. Caries prevention in pits and fissures sealed with an adhesive resin polymerized by ultraviolet light: a two-year study of a single adhesive application. JADA 82:1090 May 1971. 19. Rock, W.P. Fissure sealants. Results obtained with two different sealants after one year. Br Dent J 133:146 Aug 15, 1972. 20. Rock, W.P. Fissure sealants. Results obtained with two different bis-GMA type sealants after one year. Br Dent J 134:193 March 6, 1973. 21. McCune, R.J., and others. Pit and fissure sealants: one-year results from a study in Kalispell, Montana. JADA 87:1177 Nov 1973.
22. Rock, W.P. Fissure sealants. Further results of clinical trials. Br Dent J 136:317 April 16, 1974. 23. Horowitz, H.S.; Heifetz, S.B.; and McCune, R.J. The effec tiveness of an adhesive sealant in preventing occlusal caries: findings after two years in Kalispell, Montana. JADA 89:885 Oct 1974. 24. De Paola, P.F. The interpretation of findings in clinical caries trials. J Dent Child 4 1 :11 Jan-Feb 1974. 25. Mainland, D.; Herrera, L.; and Sutcliffe, M. Tables for use with binomial samples. NY University College of Medicine, 1956.
Foley’s Footnotes Perhaps the most valuable o f the few dental autobiographies is William G uy’s Mostly Memories—Some Digressions (1948). G uy received diplomas in both medicine and dentistry. A fter practicing medicine fo r several years he studied at the Edinburgh Dental Hospital and School, 1890-1892. A man o f versatile capa bility, he contributed richly to the interests o f British dentistry and dental educa tion as a progressive member o f the British Dental Association (president, 1914) and as dean o f his alma mater. William Guy became well known internationally because o f his pioneer and continuing efforts in the promotion o f the Federation Dentaire Internationale. In this footnote I shall give attention only to Guy’s recollections of his experiences as a student at the Edinburgh Dental Hospital and Dental School. They form an interesting and provocative commentary on many aspects of the program offered by the Edinburgh School in the early 1890s. I attended the Dental Hospital daily from 9 a.m. till noon. The afternoon I spent in the workroom at No. 11. The Dental Lectures were given either at 8 a.m. or 8 p.m. on two days o f the week. At the Dental Hospital there was one house surgeon dentist and an honorary staff, two of whom were supposed to be on duty on their appointed day of the week. In fact, the students were left very much to their own devices, with little direction from the staff. I found myself providing my own patients and materials. Gold stopping was all the rage; proficiency in this procedure was the only thing that counted in the assessment of operative skill. Gas (N2O) was administered from an antiquated apparatus. When the patient was black in the face, the anaesthetist removed the mask. Jactitation and struggling accompanied this semi-asphyxiation and impeded the operator, who sometimes took the precautionary measure of strapping his patient to the chair. Gas was used when one or two easy teeth were to be extracted, for greater numbers Chloroform was required. If a mouth was to be cleared, the necessary forceps (10 to 12) were laid on the table, and much time was consumed in changing instruments. The rubber dam was used for the exclusion of saliva in tooth filling, but unhappily saliva ejectors were not provided; the consequent dribbling often left the patients as drenched as if they had been out in the rain. There was a gold-filling competition. As there was no system for inspecting fillings and allotting marks, the Medal went to the man who had done the biggest number. One man who won it did fifteen in a sitting. Of course, they were just pinhead fillings and ought not to have been counted. I attended the lectures but was not greatly edified. None of the usual helpful items of equipment were provided by the School. I soon perceived that the whole set-up was just a makeshift. The prem ises were unsuitable, the equipment inadequate, the teaching amateurish and insufficient. The stu dents were thrown on their own resources. For want of direction and demonstration, difficulties were solved by the process of trial and error, which involved useless expenditure of time and effort. Not that the individual student was distressed or discouraged: self-help made himself-reliant. And after all, the necessary knowledge could be garnered from the printed page. Gardner P. H. Foley
G oing—others: CLINICAL EVALUATION OF A SEALANT ■ 397