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Clinical performance of sealed composite restorations placed over caries compared with sealed and unsealed amalgam restorations
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A R T I C L E S
The 2-year clinical evaluations of paired occlusal restorations are presented. Each study participant received a sealed composite restoration placed over a carious lesion and either a traditional outline-form (unsealed) amalgam or an ultraconservative sealed amalgam restoration. Caries was removed before placement of both types of amalgam restorations. No im portant clinical differences developed among the three groups of restorations.
Clinical performance of sealed composite restorations placed over caries compared with sealed and unsealed amalgam restorations Eva J. M ertz-Fair hurst, D D S Kathy M . C a ll-S m ith , D M D G eorge S. Shu ster, D D S, P h D J . Earl W illia m s, D D S
Q u in ce B. D a v is, D D S C. D o u g la s S m ith , D D S R o n a ld A. B e ll, D D S Jack D . Sherrer, D D S
D a v id R . M yers, D D S P. K en n eth M orse, P h D T h o m a s A. G a rm a n , D D S , M S V ictor E. D e lla -G iu stin a , D D S
r re s tin g caries w ith the use of sealants has been reported in the literatu re,1’11 b u t further clinical studies are needed to explore this ph en o m en o n .12 In add itio n to studying the possi bility of caries arrestm ent by sealants, this study proposed to com bine sealants w ith other restorative m aterials, such as am al gam o r a p o sterior com posite m aterial, in an effort to elim inate the need for cavity “extension for prevention,” to conserve t o o t h s t r u c t u r e , a n d to p o s s i b l y reduce or elim inate microleakage.
Screening procedures
Screening was d one in tw o visits. An oral ex am in atio n was m ade an d bitew ing rad io g rap h s were taken at the first visit. At the second visit, the presence of the lesion extending in to d en tin was co n firm ed clin ically an d radio g rap h ically , p atien t consent was obtained, an d the b aselin e resto ra tiv e a p p o in tm e n t w as scheduled.
A
Methods and materials T h is study tested the feasibility of u sin g a sealed co m p o site re sto ra tio n w ith o u t rem oval of the carious lesion an d w ith o u t cavity p rep a ra tio n except for an enam el bevel (Fig 1). In addition, these sealed com posite restorations were to be com pared w ith traditional cavity ou tlin e Class I am algam restorations and w ith u ltra conservative sealed am algam restorations (Fig 2).
Screening an d clinical evaluations were c o n d u cted u sin g calib rated evaluators (faculty members, School of Dentistry, Medical College of G eorgia.) A total of 753 patients were screened to select a study p o p u la tio n of 123 patients w ith at least one p air of Class I lesions extending in to dentin. A p a ir could be two m olars or two prem olars, b u t n ot a m olar an d a prem olar. T h e selected p atien t p o p u la tio n in clu d ed 43 m ales an d 80 females, ra n g in g in age from 8 to 52 years. T h e study design called for 150 paired study restorations; a total of 156 p airs of study restorations were placed. A ccording to a random ized treatm ent assignm ent sheet, one lesion was scheduled to be treated by a sealed com posite (CompS) restoration placed over a carious lesion, an d the other lesion was scheduled to be treated w ith either the ultraconservative sealed am algam (AGS) or the traditional cavity o u tlin e (unsealed) am algam (AGU) restoration (T able 1).
Diagnostic criteria for occlusal caries
T h e clinical d iag n o stic criteria for p it a n d fissure caries were: explorer catch an d softness; explorer catch an d evidence of u n d erm in ed , d em ineralized, o r p o ro u s enam el (such as etchedlike appearance or opacity of enam el su rro u n d in g the catch); or softness w ith clinically obvious loss of to o th structure (softness felt th ro u g h an ex istin g aperture; or enam el so soft and crum bly th a t it co uld be lost by scraping it aw ay w ith an explorer, th u s creating an ap ertu re th a t w o u ld lead to soft caries underneath). E xplorer catch alone was considered to be insufficient evidence for JADA, Vol. 115, N ovem ber 1987 ■ 689
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Fig 1 ■ Left, diagram
4
7
sh ow in g a mandibular
S
le ft p e r m a n e n t fir st m olar w ith caries in the m esial pit. Middle, th e p r e p a r a t io n o f enam el bevel only and no removal of caries. R igh t, the com posite restoration placed over c a r ie s , th e n s e a le d (CompS group).
Fig 2 ■ Diagram rep r e s e n tin g th e s tu d y design. Of 150 sealed com posite restorations (C om p S ) (le ft), each p a ir e d w it h e ith e r (m iddle) an ultracons e r v a tiv e
s e a le d
a m alg a m restoration (AGS) or (right) a tra d ition al ou tlin e form Class I unsealed am al gam restoration (AGU) in the same mouth.
clinical diagnosis of p it an d fissure caries. T h e radio g rap h ic criterion for caries w as a d e fin ite ra d io lu c e n t area at the d entinoenam el ju n c tio n (DEJ) indicating a frank lesion th a t extended in to dentin. W ith sm aller lesions, the localized radiolu cen t area of the clinically evident lesion was com pared w ith the n atu ra l rad io lu cent area of the D EJ line in the adjacent an d contralateral teeth on the bitew ing ra d io g ra p h s. L esions co n fin e d only to enam el were not accepted. Lesion depths definitely extending into dentin, and u p to h alfw a y in to d e n tin w ere accepted (halfw ay the distance in to dentin was estim ated between the D EJ an d the p u lp cham ber). T eeth w ith proxim al lesions were excluded from the study.
a large ro u n d b ur, football-shaped d ia m ond, a no. 330 bur, or a tapered bur, a c c o rd in g to o p e ra to r p referen ce. For sealed am algam restorations (AGS group), the cavity prep aratio n consisted of local ized pear-shaped reten tio n form an d no extension for p rev en tio n . For unsealed am algam restorations (AGU group), the trad itio n al Class I cavity o u tlin e form w ith ex ten sio n for p rev en tio n in to all m ajor grooves was prepared. A diagram p resenting the three types of restorative approaches is show n in Figure 2, an d a Table 1 ■ Outline of clinical methodology. Code nam e
T y p e of restoration
Baseline operative procedures
C om pS
All baseline operative procedures were per fo rm e d by fac u lty m em b ers from the School of D entistry. T h e m inim al cavity p rep a ra tio n of the sealed com posite res to r a tio n p la c e d over a c a rio u s lesion (C om pS group) consisted of an enamel bevel only, an d usually did n o t require any anesthetic injection. T h e bevel around the periphery of the cavity w as m ade w ith
AGS
C om posite restoration, sealed A m algam restoration, sealed A m algam restoration, unsealed
690 ■ JADA, Vol. 115, N ovem ber 1987
sum m ary of clinical m ethods is presented in T ab le 1. W ith b oth types of am algam restora tions, all caries was rem oved an d n o cav ity varnish was used. For the sealed com posite restoration (Com pS group), a bevel w as p rep ared w ith a rotary in stru m en t by rem oving all of the crum bly dem ineral ized enam el aro u n d the periphery of the le s io n , th e n p r e p a r in g th e b ev el in “so u n d ” (strong, noncrum bly, nonporous) enam el. T h e enam el was judged as sou n d by its clinical appearance rath er th an by the presence o r absence of u n d erm in in g caries. W ith o u t rem oving any soft caries below the bevel, the entire occlusal su r face was etched w ith a liq u id etchant (37% p h o sp h o ric acid) a n d an enam el-bonding ag en t was placed o n the bevel. T h en a radiopaque, self-curing posterior com pos ite m aterial (M iradapt) was placed. After the com posite restorative m aterial had set, it was follow ed by the ap p licatio n of a tra n s lu c e n t y ello w se lf-c u rin g se ala n t (D elton T inted). F inally, the rubber dam was rem oved a n d o cclu sal ad ju sted , if necessary (Fig 3). In the sealed com posite a n d sealed am alg am restorations (CompS an d AGS groups), no atte m p t was m ade to remove any surface stains in the rem ain in g pits an d fissures. T heoretically, the restora tions in these two g ro u p s sh o u ld involve a single p it area (for exam ple, the lesion should involve only a th ird of the occlu sal surface in the m esial, distal, or central pit) (Fig 2). T h e sm all lesion of the d ia gram in F igure 2 w ould allow the ideal ultraconservative ap p ro ach in these two study groups. H ow ever, the difficulty in finding patients w ith paired lesions extend in g in to d en tin precluded the selection of only sm all lesions for the study. T h e fact th a t usually larger th an ideal lesions were accepted for the study makes the actual study m ore strict a test th an the theoreti-
AGU
No. of restorations per group
E xtent of cavity p re p a ra tio n
C arious status at baseline
E nam el bevel only
Caries in d e n tin n o t rem oved A ll caries rem oved
156
A ll caries rem oved
78
Lim ited: no extension for prevention T rad itio n al extension for prevention*
78
•T he traditional extension for prevention as taught at Medical College of Georgia for Class I occlusal amalgam restoration includes removal of the entire central groove, extending from the mesial to the distal pits and including these pits, as well as extending the facial an d lingual grooves u p to half the distance (or less) from the central groove to the peripheral outline of the occlusal table.
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cal study design represented in Figure 2. Clinical and radiographic evaluations
T h e study restorations were evaluated clinically at 6 m onths, 1 year, an d 2 years. Modified Ryge criteria (Table 2) were used for clinical evaluations of all restorations. T h e results of the clinical evaluations are the subject of this report. T h e procedures for taking standardized rad io g rap h s were described previously.11 In the cu rren t study, standardized rad io g ra p h s w ere ta k en a t b aselin e a n d at follow -up evaluation periods. An exam p le of a r a d io g r a p h ic se q u e n c e of a c a rio u s le s io n tre a te d by th e se ale d com posite restoration (Com pS group) is show n in Figure 4; these radiographs are of the same tooth that is show n in the clinical sequence p hotographs (Fig 3). D ouble-blind radiographic evaluations are p lan n ed at the end of the study (at 6 years) an d w ill be reported later. M ean w hile, the an n u a l radiograp hs are used to alert the p rin cip al investigator in case any study tooth m ig h t appear threatened, p articularly in the sealed com posite resto ratio n over caries (Com pS group), where caries m ig h t progress if any m icroleakage occurred. Results At baseline, a total of 312 paired study restorations were placed: there were 77 sealed com posite/sealed am algam (C om pS/ AGS) p a irs a n d 79 sealed c o m p o s ite / unsealed am algam (C om pS/A G U ) pairs (a total of 156 pairs of study restorations). T h u s , th e sealed c o m p o site (C om pS ) g ro u p was twice as large (156 restorations) as each g ro u p of the two am algam types of restorations. T h e results of 6-, 12-, and 24-m onth clinical evaluations are show n in T able 3. At 6 m onths, a total of 284 (91%) of paired study restorations were evaluated: 142 restorations in the Com pS group (91%) an d 71 restorations in each am algam group, representing 92% of the AGS group and 89% of the A GU group of restorations. At 1 year, a total of 252 (81%) of paired study restorations were evaluated: 126 in the Com pS gro u p (81%) an d 63 (80%) res torations in each am algam gro u p (AGS and AGU groups). At 2 years, a total of 238 (76%) of paired study restorations were evaluated: 119 in the Com pS g ro u p (76%), 59 (77%) in the AGS group, an d 60 (76%) in the AGU group.
Fig 3 ■ An exam ple of a tooth in the sealed composite (CompS) group. Caries on the occlusal surface of a mandibular left permanent first molar in a 16-year-old female patient. T o p left, preoperative ph o tograph. N ote opacity o f demineralized, crumbly enamel around the aperture leading to the soft carious lesion. T op right, cavity preparation is bevel only, soft brownish caries left intact below the enamel bevel. Crumbly, demineralized enamel removed by the bevel, but n o attempt was made to remove the dark stains in rem aining pits and fissures. The dark stains felt hard to the explorer and were designated as surface stains rather than caries. Middle left, bonding agent and com posite restoration have been placed. Middle right, postoperative photograph. Yellow tinted sealant has been placed. Blue marks are a result of articulating paper for checking occlusion. Bottom left, restoration at 6 m onths. Bottom right, restoration at 2 years. N ote: the sealant has worn thinner and its yellow tint has faded in som e areas. T he restoration and all stained and unstained grooves remain sealed.
No changes were observed at any eval u atio n period for the criteria of color m atch, m arginal discoloration, anatom ic fo rm , a n d c a rie s a t m a rg in s o f an y restorations. Sealant retention
A m ong the sealed com posite restorations (C o m p S g r o u p ) , 72%, 74%, a n d 57% rem ained fully covered w ith sealant (Oscar rating, T able 3) at 6, 12, an d 24 m onths, respectively; 15%, 21%, an d 34% were partly covered w ith se a la n t a t 6, 12, an d 24
m onths, respectively, yet show ed no crev ice at the exposed restoration m argins (O scar/A lfa rating); an d 12%, 4%, an d 5%, respectively, had n o sealant covering the restoration, yet show ed no crevice at the m argins (Alfa rating). A t 2 years, 3% of sealed c o m p o site r e s to ra tio n s h a d n o sealant b u t had a visible crevice penetra ble by the explorer so that, w ith lig h t pressure, the explorer tin e w o u ld lodge w ith in the crevice a n d n o t move in either direction: neither from the to o th to the restoration, n o r from the restoration to the tooth. T h is lo d g in g of the explorer
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represented a two-way catch, denoting a definite V -shaped crevice between the res toration and the tooth (Bravo rating). O ne c lin ic a l f a ilu r e (C h a r lie r a tin g ) w as observed in the sealed com posite (CompS) g ro u p at 6 m onths: a p in p o in t void 3 mm deep at the m argin of the restoration. T h e single clinical failure in the sealed com posite (Com pS) g ro u p could have resulted from in c o rp o ratio n of an air bubble d u rin g m ix in g of the com posite m aterial or d u rin g the placem ent of this restorative m aterial in the cavity. T h e p in p o in t void m ust have been a subsur face p h en o m en o n , subsequently exposed by occlusal w ear and detected at the 6m o n th evalu atio n visit. T h e anatom ic form for this restoration, however, was still evaluated as Alfa because no wear facets or other discontinuities between the to o th an d the sealant were evident. T h e sm all void w as resealed and rem ains an O scar ra tin g for the curren t m arginal integrity status (at 2 years). However, the C harlie ratin g w ill co ntinue to be used
for this restoration an d is represented as 1% at 12 an d 24 m onths (Table 3). A m ong the sealed am algam (AGS) res torations, 76%, 68%, and 52% rem ained fully covered w ith sealant (Oscar rating, T ab le 3) at 6, 12, a n d 24 m onths, respec tively; 18%, 28%, an d 45% were p artly covered w ith sealant yet show ed no crev ice (O scar/A lfa rating) at 6, 12, and 24 m onths, respectively. N o sealant and no crevice were present (Alfa rating) o n 6%, 2%, an d 2% of sealed am algam (AGS) res torations a t the respective tim e intervals. M arginal crevice (Bravo rating) was not observed in this group. O ne restoration (2%) was rated as a clinical failure (C har lie rating) as of the 12-month evaluation period. T h e single clinical failure in the sealed am algam (AGS) g ro u p was observed o n a m axillary left th ird m o lar w ith difficult access to the facial surface. A g in g iv al/facial carious lesion (Class V) was noted at 6 m onths th a t h ad n o t been detected at the baseline exam ination. T h e p atien t
missed several restorative appointm ents, an d at 10 m o n th s the facial p o rtio n of the tooth became underm ined by the progress ing carious lesion, an d broke from the rem ainder of the tooth. At the 10-m onth v is it, th e a m a lg a m r e s to r a tio n its e lf
Table 2 ■ Modified Ryge criteria.
C o lo r m atch
M arginal discoloration
M arginal integrity (m arg in al a d ap tation)
O scar
R esto ratio n fully covered w ith sealant, n o bare areas o f restoration
O sc a r/ Alfa
R esto ratio n partly covered w ith sealant, no crevice a lo n g any bare m argins of restoration
A natom ic form (wear)
Caries
Alfa
G ood color m atch w ith m irro r an d d e n tal lig h t
N o m arg in al discoloration
N o sealant, n o crevice: no ex p lo rer catch o r explorer catch o n e way, b u t no two-way catch a n d n o visible crevice
N ot undercontoured, not discontinuous
N o caries a t m argins
Bravo
C o lo r m is m atch, b u t w ith in n o rm al (toothlike) range
M arginal discoloration b u t n o t pene tra tin g toward p u lp
N o sealant, crevice present: explorer catch (both ways), visible crevice b u t n o d en tin o r base is exposed
U ndercon toured a n d d isco n tin uous, b u t n either d en tin n o r base is exposed
Caries a t m argins*
C o lo r m ism atch o u tsid e norm al (outside to o th like) range*
M arginal discoloration p enetrating tow ard pulp*
Crevice so deep th a t d e n tin or base is exposed*
S ufficient restor ative m aterial is lost so that d e n tin or base is exposed*
C harlie
D entin o r base is exposed an d restoration is m obile, fractured, o r m issing* M etallic (n o t a p p licab le)
occlusal carious lesion extends into dentin from the central pit area. T he radiograph was taken before preparing the bevel and before placement of sealed com posite restoration (CompS) over car ies. M iddle, restoration and lesion at 6 months.
D elta
H otel (NA)
Fig 4 ■ R adiographs of the same tooth show n in Figure 3. T op , preoperative radiograph. The
M etallic (not applicable)
Note: the lesion appears more defined and larger at 6 m onths than at baseline. There may have been some continued progress of the carious lesion in itially w ith in the first 6 months. However, the enlarged appearance of the lesion at 6 m onths m ight have been enhanced by the contrast between the radiopaque com posite material above the radiolucent lesion (the Mach band effect).13 For radiation safety reasons, no postoperative baseline radiographs were taken. Bottom, restoration and lesion at 2 years. Note: not much change in lesion depth seems to have occurred between 6 m onths
•Clinically unacceptable ratings (clinical failures): all Charlie and Delta ratings and the Bravo rating for caries at margins.
692 ■ JADA, Vol. 115, N ovem ber 1987
and 24 months.
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ures. Both restorations were repaired w ith ease, an d con tin u e to function in the m o u th w ith n o necessity for fu rth e r treatm ent. A m ong the m odified Ryge criteria, the m arginal integrity criterion seemed to be the m ost sensitive an d disclosed other m inor changes in all three groups; how ever, no significant differences were ob served am ong the three groups.
rem ained intact, b u t the fractured facial surface of the tooth exposed the am al gam , base, and dentin on the entire facial aspect of the restoration. T h e facial w all was th en recreated, u sin g a posterior com posite restorative m aterial. T h e tooth w ith b o th restorations (occlusal sealed am algam study restoration [AGS] and the facial com posite restoration) has subse q u en tly rem ained intact. T h e ratin g for this sealed am algam (AGS) restoration w ill co n tinue to be designated as C harlie as of the tenth m onth visit an d th ro u g h o u t the rem ainder of the study; the cur re n t status of the to o th w ill also be evaluated.
Complete and partial sealant retention. C om
plete se a la n t re te n tio n in b o th sealed groups show ed a parallel decrease, as the p ercen tag e of fu lly sealed resto ra tio n s (Oscar rating) was in the 70% range at 6 m onths an d in the 50% range at 2 years in both of these groups (Table 3). T h e per centage of partly sealed restorations (Oscar/ A lfa ra tin g ) in these tw o g ro u p s had approxim ately doubled between 6 and 24 m onths; it should be noted, however, that .5 m m o r even less of “b are” m argin q ualified the restoration in b oth of these groups for the partly sealed (Oscar/A lfa) rating. In the sealed am algam (AGS) res toration, even a tiny p o rtio n of a bare m argin was easily identified because of its m etallic shine. In the sealed com posite (CompS) group, lack of sealant on any p a rt of the com posite m arg in was also easily detected by ru n n in g the explorer tine lig h tly over the surface; the rough surface of the bare com posite restoration w ould feel and sou n d different th an the sm ooth enam el or sealant surfaces, and the bare area of the com posite restoration
Marginal integrity
A m ong the unsealed am algam (AGU) res to ra tio n s , 99% re m a in e d w ith o u t any m arginal defects (Alfa rating) at 6 m onths, 94% at 12 m onths, an d 90% at 24 m onths (T able 3). A two-way explorer catch de n o tin g a crevice (Bravo rating) was found in 1%, 6%, an d 10% of the unsealed am al gam (AGU) restorations at 6, 12, an d 24 m onths, respectively. N o C harlie ratings were found in this group. N o D elta ra t ings occurred in any of the three groups of restorations. Overall, there were two clinical failures: one in the sealed com posite (CompS) g ro u p an d one in the sealed am algam (AGS) group. Both failures appeared to be erro rs in ju d g m e n t an d o p eratorrelated, rather than m aterial-related fail
w o u ld become gray as a resu lt of the ab rasio n of the m etal from the explorer by the q u artz filler particles at the surface of the com posite m aterial. Discussion T h e p u rp o se of this study was to investi gate trad itio n al versus less invasive m eth ods in the treatm ent of p it an d fissure car ies on occlusal surfaces. T h e trad itio n al o u tlin e form of the occlusal am algam res to ratio n extends in to all m ajor occlusal pits and fissures, thus fo llo w in g the co n cept of cavity extension for prevention. T h e m ain disadvantage of this trad itio n al ap p ro ach is th a t sou n d to o th structure is removed, w ith consequent w eakening of the tooth, b u t n ot always achieving the o rig in a l p u rp o se of p re v e n tin g caries. Furtherm ore, am algam restorations are subject to m arg in al breakdow n, m icro leakage, an d recurrent caries.14 23 M ost studies suggest th at m icroleakage occurs w ith all am algam restorations, w ith an d w ith o u t the cavity varnish.21”23 Sealants have been clinically proved to prevent an d even arrest caries.1’12 Sealants ■ h av e been ac ce p te d as m o re effectiv e caries-preventive agents th a n am alg am , thus m ak in g the concept of extension for prev en tio n obsolete for am alg am Class I restorations. Sealants do n o t req u ire any m echanical rem oval of sou n d tooth struc ture a n d preserve the integrity of the intact tooth. In contrast to posterior com posite restorations an d sealants, am algam does
Table 3 ■ Marginal integrity of paired restorations at 6,12, and 24 months. R estoration fully covered w ith sealant; n o bare areas of restoration
R estoration p artly covered w ith sealant; n o crevice a lo n g any bare m arg in of restoration
(Oscar) M onths
N o sealant, no crevice; clinically acceptable
(O scar/A lfa)
6
12
24
72%
74%
76%
NA
N o sealant; crevice present, b u t clinically still acceptable
(Alfa)
6
12
24
57%.
15%
21%
34%
12%
4%
68%
52%
18%
28%
45%
6%
NA
NA
NA
NA
NA
99%
6
12
Deep crevice so d e n tin or base is exposed; clinically unacceptable
R estoration m obile, fractured, or m issing
(C harlie)*
(Delta)*
(Bravo) 24
6
12
24
5%
0
0
3%
1%
1%
1%
0
2%
2%
0
0
0
0
2%
2%
0
94%
90%
1%
6%
10%
0
0
0
0
6
12
24
24
R estoration type Sealed com posite restoration (C om pS ) f Sealed a m algam restoration (A G S)f U nsealed am algam restoration (A G U )t
•Charlie and Delta ratings are clinical failures. •fOnly percentages are presented in this table; text has full discussion and actual numbers of restorations.
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not bind to the tooth, and tends to weaken it.24 T he concept of extension for preven tion and thus using amalgam to replace any sound fissures may be questioned. T he traditional cavity design for Class I amalgam restorations may also be ques tioned, and the com bination of sealants with amalgam or posterior com posite res torations may merit further consideration and study. T he benefits of removal of all clinically evident caries beneath a sealed com posite restoration versus the benefits and risks of possible caries arrestment or progression require further long-term observation. The patients in this study w ill be observed for a total of 6 years.
Conclusions N o clinically significant differences were seen am ong the three groups of restora tions at any of the evaluation periods. T h u s, sealed com p o site restoration s (CompS), sealed am algam restorations (AGS), and unsealed amalgam restorations (AGU) appeared to function equally w ell according to R yge’s m odified criteria (Table 2). T he two clinical failures in the sealed com posite (CompS) and sealed am algam (AGS) groups can probably be ascribed to operator error rather than to the failure of materials used. There was no significant difference in sealant retention between sealed com pos ite (CompS) and sealed am algam (AGS) restorations. N o sensitivity has occurred in any sealed composite (CompS) restora tion placed over caries during the initial follow -up period of 2 years. At the 2-year evaluation, a two-way explorer catch denoting a crevice at the margin (Bravo rating) occurred in 10% of the unsealed amalgam (AGU) restorations as compared with 0, or 3% in the other groups (Table 3, Bravo). It is too early, however, to conclude whether this slight difference in marginal integrity m ight be indicative of a trend in the unsealed amalgam (AGU) group. Less removal of sound tooth structure occurred in the teeth receiving the ultra conservative sealed amalgam restoration (AGS) than in teeth receiving the unsealed
694 ■ JADA, Vol. 115, November 1987
am algam restoration (AGU). T he least removal of tooth structure occurred in the sealed composite (CompS) group (bevel only). If the current trends continue in this study, then approaches that are more conservative of tooth structure and less traumatic for the patient may become an accepted practice in restorative dentistry.
-------------------J'AOA ------------------T he inform ed consent of all hum an subjects w ho participated in the experimental investigation reported or described in this manuscript was obtained after the nature o f the procedure and possible discomforts and risks had been fully explained. T h is investigation was supported by N IH grant no. DE06112. T h e authors thank Dr. Jack D. Zwemer for his assistance in the preparation of this manuscript. Information about the manufacturers of products mentioned in this article may be available from the authors. N either the authors nor the American Dental A ssociation has any commercial interest in the prod ucts mentioned. Dr. Mertz-Fairhurst is associate professor, depart m ent o f restorative dentistry, M edical C ollege of Georgia, A ugusta, GA 30912-0200. Dr. Call-Smith was consultant, codirector, and clinical operator, and is now in private practice in Atlanta. Dr. Schuster is coordinator, m icrobiology; professor oral b io lo g y / m icrobiology, restorative dentistry, and graduate stud ies; and associate professor, cell and m olecular b io l ogy; Dr. W illiam s is chair, com m unity dentistry; Dr. Davis is associate professor, department of restorative dentistry; Dr. Sm ith is associate professor, department of restorative dentistry; Dr. Bell was assistant profes sor, department o f pediatric dentistry, and is now a resident, orthodontics; Dr. Sherrer is associate profes sor, department of restorative dentistry; Dr. Myers is chair, pediatric dentistry; Dr. Morse is professor, den tal education; Dr. Garman is professor, department of restorative dentistry; Dr. Della-Giustina was associate professor, com m unity dentistry, and is now retired; all at the Medical College of Georgia. Address requests for reprints to Dr. Mertz-Fairhurst.
1. Micik, R.E. Fate of in vitro caries-like lesions sealed w ith in tooth structure. J Dent Res 51(Special Issue):225, abstract no. 710, 1972. 2. Handelman, S.L.; Buonocore, M.G.; and Heseck, D.J. A preliminary report on the effect of fissure sealant o n bacteria in dental caries. J Prosthet Dent 27(4):390-392,1972. 3. H a n d e lm a n , S.L .; B u o n o co re, M .G .; and Schoute, P.C. Progress report on the effect o f a fissure sealant on bacteria in dental caries. JADA 87(5):11891191,1973. 4. Jeronim us, D.J.; T ill, M.J.; and Sveen, O.B. Reduced viability of micro-organisms under dental
sealants. ASDC J Dent C hild 42(4):275-280, 1975. 5. Handelm an, S.L.; Washburn, F.; and Wopperer, P. Two-year report of sealant effect on bacteria in dental caries. JADA 93(5):967-970, 1976. 6. G oing, R.E., and others. T he viability of micro organism s in carious lesions five years after covering w ith a fissure sealant. JADA 97(3):455-462, 1978. 7. Mertz-Fairhurst, E.J., and others. C linical prog ress o f sealed and unsealed caries; depth changes and bacterial counts. J Prosthet Dent 42(5):521-526, 1979. 8. Mertz-Fairhurst, E.J., and others. C linical prog ress of sealed and unsealed caries: radiographs and clinical observations. J Prosthet Dent 42(6):633-637, 1979. 9. Jensen, O.E., and H andelm an, S.L. Effect of an autopolym erizing sealant on viability of microflora in occlusal dental caries. Scand J Dent Res 88(5):382-388, 1980. 10. Handelman, S.L.; Leverett, D.H.; and Iker, H.P. L ongitudinal radiographic evaluation of the progress of caries under sealants. J Pedod 9(2):119-126,1985. 11. Mertz-Fairhurst, E.J.; Schuster, G.S.; and Fairhurst, C.W. Arresting caries by sealants: results of a clinical study. JADA 112(2):194-197, 1986. 12. N ational Institutes o f H ealth Consensus Devel opm ent Conference statement on dental sealants in prevention of tooth decay. JADA 108(2):233-236,1984. 13. Berry, H.M . Cervical burnout and Mach band: two shades of doubt in radiologic interpretation of carious lesions. JADA 106(5):622-625, 1983. 14. Healey, H .J., and P h illip s, R.W. A clinical study of am algam failures. J Dent Res 28(5):439-446, 1949. 15. Richardson, A.S., and Boyd, M.A. Replacem ent of silver am algam restorations by 50 dentists during 246 w orking days. J Can Dent Assoc 39{8):556-559, 1973. 16. Bailit, H .L ., and others. A new intermediate dental outcom e measure: am algam replacement rate. Med Care 17(7):780-786, 1979. 17. Mjor, I.A. Placem ent and replacement o f resto rations. Oper Dent 6{2):49-54,1981. 18. Klausner, L .H ., and Charbeneau, G.T. A m al gam restorations: a cross sectional survey of place m ent and replacement. J M ich Dent Assoc 67(6):249252,1985. 19. Boyd, M.A., and Richardson, A.S. Frequency of am algam replacement in general practice. J Can Dent Assoc 51{10):763-766, 1985. 20. Charbeneau, G .T.; Klausner, L.H .; and Green, T .G . T h e placem ent and replacement of amalgam restorations: a national survey. J Dent Res 65(Special Issue):219, abstract no. 449, 1986. 21. G oing, R.E. Microleakage around dental resto rations: a sum m arizing review. JADA 84(6):1349-1357, 1972. 22. Fanian, F.; Hadavi, F.; and Asgar, K. Marginal leakage of dental amalgams: effect of cavity varnish and burnishing. J Can Dent Assoc 50(6);484-487, 1984. 23. Andrews, J.T ., and Hembree, J.H. Microleak age of several am algam systems: an anim al study. J Prosthet Dent 40(4):418-421, 1978. 24. Sim onsen, R.J., and Landy, N.A. Preventive resin restorations: fracture resistance and 7-year clin i cal results. J Dent Res 63(Special Issue):175, abstract no. 39, 1984.
a
A R T I C L E S
The 2-year clinical evaluations of paired occlusal restorations are presented. Each study participant received a sealed composite restoration placed over a carious lesion and either a traditional outline-form (unsealed) amalgam or an ultraconservative sealed amalgam restoration. Caries was removed before placement of both types of amalgam restorations. No im portant clinical differences developed among the three groups of restorations.
Clinical performance of sealed composite restorations placed over caries compared with sealed and unsealed amalgam restorations Eva J. M ertz-Fair hurst, D D S Kathy M . C a ll-S m ith , D M D G eorge S. Shu ster, D D S, P h D J . Earl W illia m s, D D S
Q u in ce B. D a v is, D D S C. D o u g la s S m ith , D D S R o n a ld A. B e ll, D D S Jack D . Sherrer, D D S
D a v id R . M yers, D D S P. K en n eth M orse, P h D T h o m a s A. G a rm a n , D D S , M S V ictor E. D e lla -G iu stin a , D D S
r re s tin g caries w ith the use of sealants has been reported in the literatu re,1’11 b u t further clinical studies are needed to explore this ph en o m en o n .12 In add itio n to studying the possi bility of caries arrestm ent by sealants, this study proposed to com bine sealants w ith other restorative m aterials, such as am al gam o r a p o sterior com posite m aterial, in an effort to elim inate the need for cavity “extension for prevention,” to conserve t o o t h s t r u c t u r e , a n d to p o s s i b l y reduce or elim inate microleakage.
Screening procedures
Screening was d one in tw o visits. An oral ex am in atio n was m ade an d bitew ing rad io g rap h s were taken at the first visit. At the second visit, the presence of the lesion extending in to d en tin was co n firm ed clin ically an d radio g rap h ically , p atien t consent was obtained, an d the b aselin e resto ra tiv e a p p o in tm e n t w as scheduled.
A
Methods and materials T h is study tested the feasibility of u sin g a sealed co m p o site re sto ra tio n w ith o u t rem oval of the carious lesion an d w ith o u t cavity p rep a ra tio n except for an enam el bevel (Fig 1). In addition, these sealed com posite restorations were to be com pared w ith traditional cavity ou tlin e Class I am algam restorations and w ith u ltra conservative sealed am algam restorations (Fig 2).
Screening an d clinical evaluations were c o n d u cted u sin g calib rated evaluators (faculty members, School of Dentistry, Medical College of G eorgia.) A total of 753 patients were screened to select a study p o p u la tio n of 123 patients w ith at least one p air of Class I lesions extending in to dentin. A p a ir could be two m olars or two prem olars, b u t n ot a m olar an d a prem olar. T h e selected p atien t p o p u la tio n in clu d ed 43 m ales an d 80 females, ra n g in g in age from 8 to 52 years. T h e study design called for 150 paired study restorations; a total of 156 p airs of study restorations were placed. A ccording to a random ized treatm ent assignm ent sheet, one lesion was scheduled to be treated by a sealed com posite (CompS) restoration placed over a carious lesion, an d the other lesion was scheduled to be treated w ith either the ultraconservative sealed am algam (AGS) or the traditional cavity o u tlin e (unsealed) am algam (AGU) restoration (T able 1).
Diagnostic criteria for occlusal caries
T h e clinical d iag n o stic criteria for p it a n d fissure caries were: explorer catch an d softness; explorer catch an d evidence of u n d erm in ed , d em ineralized, o r p o ro u s enam el (such as etchedlike appearance or opacity of enam el su rro u n d in g the catch); or softness w ith clinically obvious loss of to o th structure (softness felt th ro u g h an ex istin g aperture; or enam el so soft and crum bly th a t it co uld be lost by scraping it aw ay w ith an explorer, th u s creating an ap ertu re th a t w o u ld lead to soft caries underneath). E xplorer catch alone was considered to be insufficient evidence for JADA, Vol. 115, N ovem ber 1987 ■ 689
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Fig 1 ■ Left, diagram
4
7
sh ow in g a mandibular
S
le ft p e r m a n e n t fir st m olar w ith caries in the m esial pit. Middle, th e p r e p a r a t io n o f enam el bevel only and no removal of caries. R igh t, the com posite restoration placed over c a r ie s , th e n s e a le d (CompS group).
Fig 2 ■ Diagram rep r e s e n tin g th e s tu d y design. Of 150 sealed com posite restorations (C om p S ) (le ft), each p a ir e d w it h e ith e r (m iddle) an ultracons e r v a tiv e
s e a le d
a m alg a m restoration (AGS) or (right) a tra d ition al ou tlin e form Class I unsealed am al gam restoration (AGU) in the same mouth.
clinical diagnosis of p it an d fissure caries. T h e radio g rap h ic criterion for caries w as a d e fin ite ra d io lu c e n t area at the d entinoenam el ju n c tio n (DEJ) indicating a frank lesion th a t extended in to dentin. W ith sm aller lesions, the localized radiolu cen t area of the clinically evident lesion was com pared w ith the n atu ra l rad io lu cent area of the D EJ line in the adjacent an d contralateral teeth on the bitew ing ra d io g ra p h s. L esions co n fin e d only to enam el were not accepted. Lesion depths definitely extending into dentin, and u p to h alfw a y in to d e n tin w ere accepted (halfw ay the distance in to dentin was estim ated between the D EJ an d the p u lp cham ber). T eeth w ith proxim al lesions were excluded from the study.
a large ro u n d b ur, football-shaped d ia m ond, a no. 330 bur, or a tapered bur, a c c o rd in g to o p e ra to r p referen ce. For sealed am algam restorations (AGS group), the cavity prep aratio n consisted of local ized pear-shaped reten tio n form an d no extension for p rev en tio n . For unsealed am algam restorations (AGU group), the trad itio n al Class I cavity o u tlin e form w ith ex ten sio n for p rev en tio n in to all m ajor grooves was prepared. A diagram p resenting the three types of restorative approaches is show n in Figure 2, an d a Table 1 ■ Outline of clinical methodology. Code nam e
T y p e of restoration
Baseline operative procedures
C om pS
All baseline operative procedures were per fo rm e d by fac u lty m em b ers from the School of D entistry. T h e m inim al cavity p rep a ra tio n of the sealed com posite res to r a tio n p la c e d over a c a rio u s lesion (C om pS group) consisted of an enamel bevel only, an d usually did n o t require any anesthetic injection. T h e bevel around the periphery of the cavity w as m ade w ith
AGS
C om posite restoration, sealed A m algam restoration, sealed A m algam restoration, unsealed
690 ■ JADA, Vol. 115, N ovem ber 1987
sum m ary of clinical m ethods is presented in T ab le 1. W ith b oth types of am algam restora tions, all caries was rem oved an d n o cav ity varnish was used. For the sealed com posite restoration (Com pS group), a bevel w as p rep ared w ith a rotary in stru m en t by rem oving all of the crum bly dem ineral ized enam el aro u n d the periphery of the le s io n , th e n p r e p a r in g th e b ev el in “so u n d ” (strong, noncrum bly, nonporous) enam el. T h e enam el was judged as sou n d by its clinical appearance rath er th an by the presence o r absence of u n d erm in in g caries. W ith o u t rem oving any soft caries below the bevel, the entire occlusal su r face was etched w ith a liq u id etchant (37% p h o sp h o ric acid) a n d an enam el-bonding ag en t was placed o n the bevel. T h en a radiopaque, self-curing posterior com pos ite m aterial (M iradapt) was placed. After the com posite restorative m aterial had set, it was follow ed by the ap p licatio n of a tra n s lu c e n t y ello w se lf-c u rin g se ala n t (D elton T inted). F inally, the rubber dam was rem oved a n d o cclu sal ad ju sted , if necessary (Fig 3). In the sealed com posite a n d sealed am alg am restorations (CompS an d AGS groups), no atte m p t was m ade to remove any surface stains in the rem ain in g pits an d fissures. T heoretically, the restora tions in these two g ro u p s sh o u ld involve a single p it area (for exam ple, the lesion should involve only a th ird of the occlu sal surface in the m esial, distal, or central pit) (Fig 2). T h e sm all lesion of the d ia gram in F igure 2 w ould allow the ideal ultraconservative ap p ro ach in these two study groups. H ow ever, the difficulty in finding patients w ith paired lesions extend in g in to d en tin precluded the selection of only sm all lesions for the study. T h e fact th a t usually larger th an ideal lesions were accepted for the study makes the actual study m ore strict a test th an the theoreti-
AGU
No. of restorations per group
E xtent of cavity p re p a ra tio n
C arious status at baseline
E nam el bevel only
Caries in d e n tin n o t rem oved A ll caries rem oved
156
A ll caries rem oved
78
Lim ited: no extension for prevention T rad itio n al extension for prevention*
78
•T he traditional extension for prevention as taught at Medical College of Georgia for Class I occlusal amalgam restoration includes removal of the entire central groove, extending from the mesial to the distal pits and including these pits, as well as extending the facial an d lingual grooves u p to half the distance (or less) from the central groove to the peripheral outline of the occlusal table.
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cal study design represented in Figure 2. Clinical and radiographic evaluations
T h e study restorations were evaluated clinically at 6 m onths, 1 year, an d 2 years. Modified Ryge criteria (Table 2) were used for clinical evaluations of all restorations. T h e results of the clinical evaluations are the subject of this report. T h e procedures for taking standardized rad io g rap h s were described previously.11 In the cu rren t study, standardized rad io g ra p h s w ere ta k en a t b aselin e a n d at follow -up evaluation periods. An exam p le of a r a d io g r a p h ic se q u e n c e of a c a rio u s le s io n tre a te d by th e se ale d com posite restoration (Com pS group) is show n in Figure 4; these radiographs are of the same tooth that is show n in the clinical sequence p hotographs (Fig 3). D ouble-blind radiographic evaluations are p lan n ed at the end of the study (at 6 years) an d w ill be reported later. M ean w hile, the an n u a l radiograp hs are used to alert the p rin cip al investigator in case any study tooth m ig h t appear threatened, p articularly in the sealed com posite resto ratio n over caries (Com pS group), where caries m ig h t progress if any m icroleakage occurred. Results At baseline, a total of 312 paired study restorations were placed: there were 77 sealed com posite/sealed am algam (C om pS/ AGS) p a irs a n d 79 sealed c o m p o s ite / unsealed am algam (C om pS/A G U ) pairs (a total of 156 pairs of study restorations). T h u s , th e sealed c o m p o site (C om pS ) g ro u p was twice as large (156 restorations) as each g ro u p of the two am algam types of restorations. T h e results of 6-, 12-, and 24-m onth clinical evaluations are show n in T able 3. At 6 m onths, a total of 284 (91%) of paired study restorations were evaluated: 142 restorations in the Com pS group (91%) an d 71 restorations in each am algam group, representing 92% of the AGS group and 89% of the A GU group of restorations. At 1 year, a total of 252 (81%) of paired study restorations were evaluated: 126 in the Com pS gro u p (81%) an d 63 (80%) res torations in each am algam gro u p (AGS and AGU groups). At 2 years, a total of 238 (76%) of paired study restorations were evaluated: 119 in the Com pS g ro u p (76%), 59 (77%) in the AGS group, an d 60 (76%) in the AGU group.
Fig 3 ■ An exam ple of a tooth in the sealed composite (CompS) group. Caries on the occlusal surface of a mandibular left permanent first molar in a 16-year-old female patient. T o p left, preoperative ph o tograph. N ote opacity o f demineralized, crumbly enamel around the aperture leading to the soft carious lesion. T op right, cavity preparation is bevel only, soft brownish caries left intact below the enamel bevel. Crumbly, demineralized enamel removed by the bevel, but n o attempt was made to remove the dark stains in rem aining pits and fissures. The dark stains felt hard to the explorer and were designated as surface stains rather than caries. Middle left, bonding agent and com posite restoration have been placed. Middle right, postoperative photograph. Yellow tinted sealant has been placed. Blue marks are a result of articulating paper for checking occlusion. Bottom left, restoration at 6 m onths. Bottom right, restoration at 2 years. N ote: the sealant has worn thinner and its yellow tint has faded in som e areas. T he restoration and all stained and unstained grooves remain sealed.
No changes were observed at any eval u atio n period for the criteria of color m atch, m arginal discoloration, anatom ic fo rm , a n d c a rie s a t m a rg in s o f an y restorations. Sealant retention
A m ong the sealed com posite restorations (C o m p S g r o u p ) , 72%, 74%, a n d 57% rem ained fully covered w ith sealant (Oscar rating, T able 3) at 6, 12, an d 24 m onths, respectively; 15%, 21%, an d 34% were partly covered w ith se a la n t a t 6, 12, an d 24
m onths, respectively, yet show ed no crev ice at the exposed restoration m argins (O scar/A lfa rating); an d 12%, 4%, an d 5%, respectively, had n o sealant covering the restoration, yet show ed no crevice at the m argins (Alfa rating). A t 2 years, 3% of sealed c o m p o site r e s to ra tio n s h a d n o sealant b u t had a visible crevice penetra ble by the explorer so that, w ith lig h t pressure, the explorer tin e w o u ld lodge w ith in the crevice a n d n o t move in either direction: neither from the to o th to the restoration, n o r from the restoration to the tooth. T h is lo d g in g of the explorer
M ertz-F airhurst-O thers : PE R FO R M A N C E O F C O M PO S IT E RESIN S PL A C E D O V E R CARIES ■ 691
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represented a two-way catch, denoting a definite V -shaped crevice between the res toration and the tooth (Bravo rating). O ne c lin ic a l f a ilu r e (C h a r lie r a tin g ) w as observed in the sealed com posite (CompS) g ro u p at 6 m onths: a p in p o in t void 3 mm deep at the m argin of the restoration. T h e single clinical failure in the sealed com posite (Com pS) g ro u p could have resulted from in c o rp o ratio n of an air bubble d u rin g m ix in g of the com posite m aterial or d u rin g the placem ent of this restorative m aterial in the cavity. T h e p in p o in t void m ust have been a subsur face p h en o m en o n , subsequently exposed by occlusal w ear and detected at the 6m o n th evalu atio n visit. T h e anatom ic form for this restoration, however, was still evaluated as Alfa because no wear facets or other discontinuities between the to o th an d the sealant were evident. T h e sm all void w as resealed and rem ains an O scar ra tin g for the curren t m arginal integrity status (at 2 years). However, the C harlie ratin g w ill co ntinue to be used
for this restoration an d is represented as 1% at 12 an d 24 m onths (Table 3). A m ong the sealed am algam (AGS) res torations, 76%, 68%, and 52% rem ained fully covered w ith sealant (Oscar rating, T ab le 3) at 6, 12, a n d 24 m onths, respec tively; 18%, 28%, an d 45% were p artly covered w ith sealant yet show ed no crev ice (O scar/A lfa rating) at 6, 12, and 24 m onths, respectively. N o sealant and no crevice were present (Alfa rating) o n 6%, 2%, an d 2% of sealed am algam (AGS) res torations a t the respective tim e intervals. M arginal crevice (Bravo rating) was not observed in this group. O ne restoration (2%) was rated as a clinical failure (C har lie rating) as of the 12-month evaluation period. T h e single clinical failure in the sealed am algam (AGS) g ro u p was observed o n a m axillary left th ird m o lar w ith difficult access to the facial surface. A g in g iv al/facial carious lesion (Class V) was noted at 6 m onths th a t h ad n o t been detected at the baseline exam ination. T h e p atien t
missed several restorative appointm ents, an d at 10 m o n th s the facial p o rtio n of the tooth became underm ined by the progress ing carious lesion, an d broke from the rem ainder of the tooth. At the 10-m onth v is it, th e a m a lg a m r e s to r a tio n its e lf
Table 2 ■ Modified Ryge criteria.
C o lo r m atch
M arginal discoloration
M arginal integrity (m arg in al a d ap tation)
O scar
R esto ratio n fully covered w ith sealant, n o bare areas o f restoration
O sc a r/ Alfa
R esto ratio n partly covered w ith sealant, no crevice a lo n g any bare m argins of restoration
A natom ic form (wear)
Caries
Alfa
G ood color m atch w ith m irro r an d d e n tal lig h t
N o m arg in al discoloration
N o sealant, n o crevice: no ex p lo rer catch o r explorer catch o n e way, b u t no two-way catch a n d n o visible crevice
N ot undercontoured, not discontinuous
N o caries a t m argins
Bravo
C o lo r m is m atch, b u t w ith in n o rm al (toothlike) range
M arginal discoloration b u t n o t pene tra tin g toward p u lp
N o sealant, crevice present: explorer catch (both ways), visible crevice b u t n o d en tin o r base is exposed
U ndercon toured a n d d isco n tin uous, b u t n either d en tin n o r base is exposed
Caries a t m argins*
C o lo r m ism atch o u tsid e norm al (outside to o th like) range*
M arginal discoloration p enetrating tow ard pulp*
Crevice so deep th a t d e n tin or base is exposed*
S ufficient restor ative m aterial is lost so that d e n tin or base is exposed*
C harlie
D entin o r base is exposed an d restoration is m obile, fractured, o r m issing* M etallic (n o t a p p licab le)
occlusal carious lesion extends into dentin from the central pit area. T he radiograph was taken before preparing the bevel and before placement of sealed com posite restoration (CompS) over car ies. M iddle, restoration and lesion at 6 months.
D elta
H otel (NA)
Fig 4 ■ R adiographs of the same tooth show n in Figure 3. T op , preoperative radiograph. The
M etallic (not applicable)
Note: the lesion appears more defined and larger at 6 m onths than at baseline. There may have been some continued progress of the carious lesion in itially w ith in the first 6 months. However, the enlarged appearance of the lesion at 6 m onths m ight have been enhanced by the contrast between the radiopaque com posite material above the radiolucent lesion (the Mach band effect).13 For radiation safety reasons, no postoperative baseline radiographs were taken. Bottom, restoration and lesion at 2 years. Note: not much change in lesion depth seems to have occurred between 6 m onths
•Clinically unacceptable ratings (clinical failures): all Charlie and Delta ratings and the Bravo rating for caries at margins.
692 ■ JADA, Vol. 115, N ovem ber 1987
and 24 months.
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ures. Both restorations were repaired w ith ease, an d con tin u e to function in the m o u th w ith n o necessity for fu rth e r treatm ent. A m ong the m odified Ryge criteria, the m arginal integrity criterion seemed to be the m ost sensitive an d disclosed other m inor changes in all three groups; how ever, no significant differences were ob served am ong the three groups.
rem ained intact, b u t the fractured facial surface of the tooth exposed the am al gam , base, and dentin on the entire facial aspect of the restoration. T h e facial w all was th en recreated, u sin g a posterior com posite restorative m aterial. T h e tooth w ith b o th restorations (occlusal sealed am algam study restoration [AGS] and the facial com posite restoration) has subse q u en tly rem ained intact. T h e ratin g for this sealed am algam (AGS) restoration w ill co n tinue to be designated as C harlie as of the tenth m onth visit an d th ro u g h o u t the rem ainder of the study; the cur re n t status of the to o th w ill also be evaluated.
Complete and partial sealant retention. C om
plete se a la n t re te n tio n in b o th sealed groups show ed a parallel decrease, as the p ercen tag e of fu lly sealed resto ra tio n s (Oscar rating) was in the 70% range at 6 m onths an d in the 50% range at 2 years in both of these groups (Table 3). T h e per centage of partly sealed restorations (Oscar/ A lfa ra tin g ) in these tw o g ro u p s had approxim ately doubled between 6 and 24 m onths; it should be noted, however, that .5 m m o r even less of “b are” m argin q ualified the restoration in b oth of these groups for the partly sealed (Oscar/A lfa) rating. In the sealed am algam (AGS) res toration, even a tiny p o rtio n of a bare m argin was easily identified because of its m etallic shine. In the sealed com posite (CompS) group, lack of sealant on any p a rt of the com posite m arg in was also easily detected by ru n n in g the explorer tine lig h tly over the surface; the rough surface of the bare com posite restoration w ould feel and sou n d different th an the sm ooth enam el or sealant surfaces, and the bare area of the com posite restoration
Marginal integrity
A m ong the unsealed am algam (AGU) res to ra tio n s , 99% re m a in e d w ith o u t any m arginal defects (Alfa rating) at 6 m onths, 94% at 12 m onths, an d 90% at 24 m onths (T able 3). A two-way explorer catch de n o tin g a crevice (Bravo rating) was found in 1%, 6%, an d 10% of the unsealed am al gam (AGU) restorations at 6, 12, an d 24 m onths, respectively. N o C harlie ratings were found in this group. N o D elta ra t ings occurred in any of the three groups of restorations. Overall, there were two clinical failures: one in the sealed com posite (CompS) g ro u p an d one in the sealed am algam (AGS) group. Both failures appeared to be erro rs in ju d g m e n t an d o p eratorrelated, rather than m aterial-related fail
w o u ld become gray as a resu lt of the ab rasio n of the m etal from the explorer by the q u artz filler particles at the surface of the com posite m aterial. Discussion T h e p u rp o se of this study was to investi gate trad itio n al versus less invasive m eth ods in the treatm ent of p it an d fissure car ies on occlusal surfaces. T h e trad itio n al o u tlin e form of the occlusal am algam res to ratio n extends in to all m ajor occlusal pits and fissures, thus fo llo w in g the co n cept of cavity extension for prevention. T h e m ain disadvantage of this trad itio n al ap p ro ach is th a t sou n d to o th structure is removed, w ith consequent w eakening of the tooth, b u t n ot always achieving the o rig in a l p u rp o se of p re v e n tin g caries. Furtherm ore, am algam restorations are subject to m arg in al breakdow n, m icro leakage, an d recurrent caries.14 23 M ost studies suggest th at m icroleakage occurs w ith all am algam restorations, w ith an d w ith o u t the cavity varnish.21”23 Sealants have been clinically proved to prevent an d even arrest caries.1’12 Sealants ■ h av e been ac ce p te d as m o re effectiv e caries-preventive agents th a n am alg am , thus m ak in g the concept of extension for prev en tio n obsolete for am alg am Class I restorations. Sealants do n o t req u ire any m echanical rem oval of sou n d tooth struc ture a n d preserve the integrity of the intact tooth. In contrast to posterior com posite restorations an d sealants, am algam does
Table 3 ■ Marginal integrity of paired restorations at 6,12, and 24 months. R estoration fully covered w ith sealant; n o bare areas of restoration
R estoration p artly covered w ith sealant; n o crevice a lo n g any bare m arg in of restoration
(Oscar) M onths
N o sealant, no crevice; clinically acceptable
(O scar/A lfa)
6
12
24
72%
74%
76%
NA
N o sealant; crevice present, b u t clinically still acceptable
(Alfa)
6
12
24
57%.
15%
21%
34%
12%
4%
68%
52%
18%
28%
45%
6%
NA
NA
NA
NA
NA
99%
6
12
Deep crevice so d e n tin or base is exposed; clinically unacceptable
R estoration m obile, fractured, or m issing
(C harlie)*
(Delta)*
(Bravo) 24
6
12
24
5%
0
0
3%
1%
1%
1%
0
2%
2%
0
0
0
0
2%
2%
0
94%
90%
1%
6%
10%
0
0
0
0
6
12
24
24
R estoration type Sealed com posite restoration (C om pS ) f Sealed a m algam restoration (A G S)f U nsealed am algam restoration (A G U )t
•Charlie and Delta ratings are clinical failures. •fOnly percentages are presented in this table; text has full discussion and actual numbers of restorations.
M ertz-F airhurst-O thers : PE R FO R M A N C E O F C O M PO S IT E RESINS PLA CED O V ER CARIES ■ 693
ARTICLES
not bind to the tooth, and tends to weaken it.24 T he concept of extension for preven tion and thus using amalgam to replace any sound fissures may be questioned. T he traditional cavity design for Class I amalgam restorations may also be ques tioned, and the com bination of sealants with amalgam or posterior com posite res torations may merit further consideration and study. T he benefits of removal of all clinically evident caries beneath a sealed com posite restoration versus the benefits and risks of possible caries arrestment or progression require further long-term observation. The patients in this study w ill be observed for a total of 6 years.
Conclusions N o clinically significant differences were seen am ong the three groups of restora tions at any of the evaluation periods. T h u s, sealed com p o site restoration s (CompS), sealed am algam restorations (AGS), and unsealed amalgam restorations (AGU) appeared to function equally w ell according to R yge’s m odified criteria (Table 2). T he two clinical failures in the sealed com posite (CompS) and sealed am algam (AGS) groups can probably be ascribed to operator error rather than to the failure of materials used. There was no significant difference in sealant retention between sealed com pos ite (CompS) and sealed am algam (AGS) restorations. N o sensitivity has occurred in any sealed composite (CompS) restora tion placed over caries during the initial follow -up period of 2 years. At the 2-year evaluation, a two-way explorer catch denoting a crevice at the margin (Bravo rating) occurred in 10% of the unsealed amalgam (AGU) restorations as compared with 0, or 3% in the other groups (Table 3, Bravo). It is too early, however, to conclude whether this slight difference in marginal integrity m ight be indicative of a trend in the unsealed amalgam (AGU) group. Less removal of sound tooth structure occurred in the teeth receiving the ultra conservative sealed amalgam restoration (AGS) than in teeth receiving the unsealed
694 ■ JADA, Vol. 115, November 1987
am algam restoration (AGU). T he least removal of tooth structure occurred in the sealed composite (CompS) group (bevel only). If the current trends continue in this study, then approaches that are more conservative of tooth structure and less traumatic for the patient may become an accepted practice in restorative dentistry.
-------------------J'AOA ------------------T he inform ed consent of all hum an subjects w ho participated in the experimental investigation reported or described in this manuscript was obtained after the nature o f the procedure and possible discomforts and risks had been fully explained. T h is investigation was supported by N IH grant no. DE06112. T h e authors thank Dr. Jack D. Zwemer for his assistance in the preparation of this manuscript. Information about the manufacturers of products mentioned in this article may be available from the authors. N either the authors nor the American Dental A ssociation has any commercial interest in the prod ucts mentioned. Dr. Mertz-Fairhurst is associate professor, depart m ent o f restorative dentistry, M edical C ollege of Georgia, A ugusta, GA 30912-0200. Dr. Call-Smith was consultant, codirector, and clinical operator, and is now in private practice in Atlanta. Dr. Schuster is coordinator, m icrobiology; professor oral b io lo g y / m icrobiology, restorative dentistry, and graduate stud ies; and associate professor, cell and m olecular b io l ogy; Dr. W illiam s is chair, com m unity dentistry; Dr. Davis is associate professor, department of restorative dentistry; Dr. Sm ith is associate professor, department of restorative dentistry; Dr. Bell was assistant profes sor, department o f pediatric dentistry, and is now a resident, orthodontics; Dr. Sherrer is associate profes sor, department of restorative dentistry; Dr. Myers is chair, pediatric dentistry; Dr. Morse is professor, den tal education; Dr. Garman is professor, department of restorative dentistry; Dr. Della-Giustina was associate professor, com m unity dentistry, and is now retired; all at the Medical College of Georgia. Address requests for reprints to Dr. Mertz-Fairhurst.
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