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Incidence of white spot formation after bonding and banding
Incidence of white spot Jbmxation after bonding and banding Leonard Gorelick,* Arnold M. Geiger,** Stony Brook and New York, N. Y.
and A. John
Gwinnett***
White spots or areas of decalcification are carious lesions of varying extent. The incidence and severity of white spots after a full term of orthodontic treatment were studied among patients in the separate private practices of two of the authors. To establish a base line of comparison, the presence of white spots in a random sample of untreated persons was observed. The incidence of white spots among patients treated by a multibonded technique was recorded at the time of debonding. In addition, white spots were sought in the before- and after-treatment Kodachrome slides of persons whose maxillary incisors had been handed. It was found that individual teeth, banded or bonded, exhibited significantly more white spot formation than was found in the control group. For the teeth studied, there was no difference in white spot formation in those that were banded or bonded. The labiogingival area of the maxillary lateral incisors had the highest incidence of white spots, When studied by segments, the highest incidence occurred among the maxillary incisors; the lowest was in the maxillary posterior segment. No white spots were found on the lingual surfaces of mandibular canines and incisors after prolonged use of a canine-to-canine bonded retainer. These findings suggest a relationship between resistance to white spot formation and the rate of salivary flow. Despite the lack of any preventive fluoride program among the study groups, 50% of the patients demonstrated resistance to white spot formation, The obvious degree of iatrogenic damage during orthodontic treatment suggests the need for preventive programs using fluoride. Further clinical research is needed.
Key words: White spots, decalcification, caries resistance
iatrogenic,
E
name1 decalcification or white spot formation can occur whenever bacterial plaque is retained on the enamel surface for a prolonged period. The white spots caused by the decalcification (nondevelopmental) process can usually be differentiated from abnormal enamel calcification of developmental origin on the basis of location, shape, and dimensional stability with time, although when this developmental anomaly exists in the labiogingival area it may be confused with decalcification. Enamel decalcification has been identified in conjunction with orthodontic treatment. With the changes in technology which permit bonding rather than banding of teeth and the availability of preventive regimens, including fluoride, the frequency, prevention, and treatment of such iatrogenic damage have received renewed attention. *Staff Orthodontist, Long Island Jewish/Hillside Medical Center; Associate Professor, Department of Children’s Dentistry (Orthodontics), School of Dental Medicine, State University of New York at Stony Brook. **Associate Clinical Professor, School of Dental and Oral Surgery, Columbia University, New York, N. Y. ***Professor, Department of Oral Biology and Pathology, School of Dental Medicine, State University of New York at Stony Brook. 0002-9416/82/020093+06$00.60/0
0
1982 The C. V. Mosby Co.
bonding,
banding,
salivary flow, caries susceptibility,
The purpose of this article is to present the histopathologic characteristics of the lesion and clinical evidence addressed to the following questions: 1. What is the frequency of occurrence of white spot formation after full-term orthodontic treatment? 2. Is there a particular susceptibility of certain teeth to white spot formation? 3. Is the incidence and distribution of decalcification different if teeth are banded or bonded? 4. Does the duration of treatment significantly increase the risk of decalcification? Histopathology
of the white
spot
lesion.
Early enamel caries is manifested clinically as a white spot lesion. The appearance is caused by an optical phenomenon owing to subsurface tissue loss and is exaggerated by thorough drying. Evidence continues to mount in support of the acidogenic theory of caries5 which can involve the full thickness of enamel and extend well into dentin before cavitation begins. Since Nishimura’j first described the phenomenon of zonation in the early carious lesion, there have been several studies’-” detailing the structural features of enamel caries. 93
94
Gorelick,
Geiger, and Gwinnett
Fig. 1. A longitudinal ground section through an early carious lesion of enamel mounted in ethyl alcohol. In this polarized light photomicrograph the subsurface body of the lesion (B) and the dark zone (0) are well defined.
The zones in the lesion can be expressed in terms of spaces present” 7 or, conversely, tissue loss. Fig. 1 shows a section through an early enamel lesion. The first zone of histologic change is called the translucent zone. Here there is an absence of structural rod outlines and a tenfold increase in the amount of space compared to normal, unaffected enamel. Progressing into the lesion, the next zone is the dark or positive zone. The latter is named for its appearance in polarized light microscopy. This zone exhibits a further increase in the volume of spaces. It has been suggested’ that the translucent zone results from preferential dissolution of structure at the rod periphery, which then proceeds to the cross striations producing the dark zone. It has been shown,8 however, that remineralization occurs in the dark zone. Finally, the core of the rods is involved, producing a zone of maximum tissue destruction termed the body of the lesion. The outermost layer of enamel (that is, above the lesion) remains relatively intact and appears radiopaque in contact radiographs (Fig. 2). It is also a zone of remineralization.” This persistent layer has been explained on the basis of the interfacial chemistry between plaque and enamel. While there are several studies which report the successful remineralization of artificial carious lesions using calcifying media, there is a need for clinical research in this area. MATERIAL Direct examination
Child patients from the practices of two of us (L. G. and A. M. G.) were selected at random and examined for the presence of nondevelopmental white spots prior to the placement of any orthodontic Control
group.
Am. J. Orthod. February 1982
Fig. 2. A contact
microradiograph showing subsurface loss in an early enamel lesion with the surface enamel ing relatively intact.
mineral appear-
brackets or bands. This group of fifty children provided a base line of the expected incidence of white spots independent of any orthodontic procedures. Since this was a retrospective study group, strict comparisons with the treatment group were not intended. Bonded teeth. Patients in the practice of one of us (L. G.) were routinely examined for the presence of nondevelopmental white spots immediately yfrer removal of all bonded brackets. Of the 121 patients, forty-nine were boys and seveny-two were girls. All of these patients were children under 18 years of age who had worn bonded appliances for an average of 23.5 months. A total of 2,211 teeth were debonded and examined clinically for white spot formation. None of the patients was on a preventive fluoride program other than routine use of a fluoride toothpaste. Indirect
slide
examination-banded
teeth
From the records of one of the authors (A. G.), Kodachrome slides of the maxillary incisors taken before banding and after band removal were examined for white spot formation. Cases were selected at random. The photographs of seventy-one children (thirty-two boys, thirty-nine girls) were examined. In all, 280 teeth, which had been banded for an average of 26 months, were examined. Direct examination-bonded retainers
canine-to-canine
Patients who had worn bonded mandibular canineto-canine lingual retainers were recalled and observed clinically for white spot formation. Sixty children who had worn such retainers for an average of 24 months were examined.
White spot formation
Volume 81 Number 2
after bonding and banding
I. Frequency of white spot formation of untreated individual teeth
0 0n
Table
Percent affected
Tooth type Maxillary central incisor Maxillary lateral incisor Mandibular first molar Mandibular second premolar Maxillary first molar Mandibular first premolar Maxillary second premolar Mandibular central incisor Mandibular canine Maxillary canine Mandibular lateral incisor Maxillary first premolar
7.0 7.0 6.0 4.0 4.0 3.0 2.0 2.0 1.0 1.0 0.0 0.0
METHOD Direct examination
Clinical examination for the presence of white spots was made on the labial surface of individual teeth and, as shown in Fig. 3, the lesions were scored as follows: 1. No white spot formation. 2. Slight white spot formation. 3. Excessive white spot formation. 4. White spot formation with cavitation. In the group that had worn bonded metal orthodontic brackets, all teeth were examined immediately after debonding at the termination of orthodontic treatment and were scored as described. Indirect
slide
examination-banded
1 = None
2 = Slight
n
3 = Severe
4 = Cavitation Fig. 3. Schematic were
representation
95
of manner
l in which
the lesions
scored.
teeth
Patients whose maxillary incisors had been banded during orthodontic treatment were studied by means of before and after-treatment Kodachrome slides taken at the same angulation. The slides were projected and viewed on two separate occasions by two of us. The observations were completely consistent and reliable and were scored in the manner described above.
location of white spots related to orthodontic therapy. Of the total of 1,006 teeth examined, thirty-six (3.6 per cent) had slight white spot formation and none had excessive white spots or cavitation. Individual teeth with white spots were placed in order from the most to the least frequent, the distribution of which is seen in Table I.
After
Incidence
lingual
retainers
Those persons who had worn bonded lingual retainers were recalled for clinical inspection. Observations for decalcification were made not only of the lingual surfaces of the canines which had been bonded but also of the lingual surfaces of the incisors against which the retaining wire had rested. RESULTS Incidence
of white
spots-Control
group
Among the fifty children in the control group, twenty-seven were boys and twenty-three were girls. In twelve cases (24 per cent) at least one tooth had a nondevelopmental lesion that might be associated with the
of carious
white
spots-bonded
Of the entire sample of 121 patients who had been debonded, 49.6 per cent had white spot formation on at least one tooth. The incidence was 44 per cent for boys and 54 per cent for girls. Of the total of 2,211 teeth examined, however, only 10.8 per cent had white spots. In actuality, there was a large variation in the number of white spots per patient. Study of the frequency of white spots by segments (Table II) revealed that the highest percentage of incidence was found in the maxillary anterior and mandibular posterior segments 15.3 per cent and 14.1 per cent, respectively. The mandibular anterior (9.4 per cent) and maxillary posterior segments (4.5 per cent) exhib-
96
Gorelick,
Geiger,
and
Am. .I. Orrhod. Frhruun 1982
Gwinnett
II. Incidence of white spot formation by segments
Table
70-
6050-
Segment
No. oj teeth bonded
Incidence oj white spar (percent)
Mandibular molars and premolars Maxillary canines and incisors Mandibular canines and incisors Maxillary molars and premolars Total
491 686 650 384 2211
15.3 14.1 9.4 4.5 11.3
40-
Ill. Incidence of white spot formation by segments (right versus left)
Table
30-
Segments
I
i
o
6
! UPPER LOWER
1
No. teeth bonded
Incidence white spots average (%)
245 246
18.0 12.7
339 347
14.2 14.0
324 326
10.6 8.3
193 191
4.5 4.5
I
123456
LEFT
UPPER
RIGHT
LEFT
LOWER
RIGHT
Mandibular molars and premolars Right Left Maxillary canines and incisors Right Left Mandibular canines and incisors Right Left Maxillary molars and premolars Right Left
IV. Frequency of white spot formation of individual teeth (bonded group)
Table 60-
Tooth
7060901000
NONE 1
u
SLIGHT
2
SEVERE
3
Fig. 4. Histogram showing the frequency spots in each tooth in the dentition.
m
CAVITATION
4 and severity
of white
ited white spot formation less frequently. The difference between the most and least frequent was 10.8 per cent, significant at the 0.5 level. All segments were studied for differences in incidence of white spots between the right and left sides of the dentition (Table III). No differences were found
type
Maxillary lateral incisor Mandibular canine Mandibular first premolar Mandibular first molar Mandibular second premolar Maxillary canine Maxillary first premolar Maxillary central incisor Mandibular lateral incisor Maxillary second premolar Mandibular central incisor Maxillary first molar
Percent
affected 23.0 18.0 17.5 14.5 14.1 11.2 9.6 8.4 8.0 3.0 2.5 1.0
between the right and left sides in the maxilla. In the mandible, the right posterior segment and the left anterior segment showed a greater incidence than their contralateral sides. These findings were not significant. The frequency and severity of white spots for each tooth in the dentition are shown in the histogram (Fig.
White spotformation
Volume 81 Number 2
4). The highest incidence was found among the maxillary lateral incisors (23 per cent). The incidence for maxillary central incisors was 8.4 per cent, almost three times less than that found for the lateral incisors. The frequency of occurrence of white spots for individual teeth, when listed from the most to the least frequent, is shown in Table IV. The more severe white spots (recorded as 3 and 4 at clinical examination) were found in only eight patients, four boys and four girls, and involved only twelve teeth. Cavitation was found in seven teeth, involving the maxillary anterior teeth and mandibular molars. The average time that these teeth were bonded was 22 months. This time span was not different from the average bond time of the entire sample. Incidence
of carious
white
spots-banded
Of the 280 maxillary incisors studied from Kodachrome slides, 12 per cent showed some white spot formation after band removal. The incidence was 17 per cent for maxillary lateral incisors and 7 per cent for the central incisors. The average time span for the sample was 26 months. The distribution of the white spots found on the right and left sides was equal. The incidence of white spots was unrelated to the longevity of banding (minimum duration of banding, 12 months). There were nine teeth that exhibited more severe white spot formation. These were 4 per cent of the sample and, with the exception of one central incisor, were lateral incisors. The average time that these teeth were banded was not different from that of the entire sample. Incidence of white canine-to-canine
spots
with bonded
lingual
No white spot formation was found on the lingual surface of the mandibular bonded incisor or canines in any of the sixty patients recalled for this examination. Also, no decalcification was found on the lingual surfaces of nonbonded incisors, despite accumulations of stain and supragingival calculus alongside and beneath the retaining wire in many persons. DISCUSSION
Examination of the control group recorded white spots induced by plaque accumulation as well as those of developmental origin. This aspect of the study was undertaken to provide a clinical description of the incidence of white spots on the labial surfaces of teeth in a random population prior to any orthodontic procedures. The maxillary incisors and the mandibular molars and second premolars had the highest incidence of white spot formation (about 7 per cent).
after
bonding and banding 97
In the group whose teeth had been bonded, study by segments showed that the mandibular posterior (15 per cent) and maxillary anterior (14 per cent) teeth had the highest incidence of white spot formation. The marked increase in white spots in these segments over that found in the control group was consistent for all other segments, but in varying degrees. Study by right and left sides of the dentition and maxillary and mandibular arches showed no consistent associations in the distribution of white spots. The incidence of white spots after debonding was reviewed for individual teeth (Table IV). The maxillary lateral incisors had the highest incidence of decalcification (21 per cent), which was almost three times as frequent as that found for the central incisors. The maxillary and mandibular canines and premolars had a high incidence of white spots and, when related to the control group, the increase for these teeth was disproportionately high. The incidence of white spots for the mandibular molars was more consistent with the incidence in the control group. The maxillary molars, on the other hand, showed no differences between the bonded and control groups. The photographic observation of teeth that had been banded was restricted to the maxillary incisors. The maxillary lateral incisors experienced white spot formation most frequently (17 per cent), about two and one-half times as frequently as the central incisors (Table IV). Hirschfield” reported a 33 per cent incidence of white spots for thirty banded right maxillary lateral incisors. Comparison of the incidence of the maxillary incisors of the banded group with those of the bonded group shows a similarity of experience, and both groups clearly showed more decalcification than the control group. In both the banded and the bonded groups the length of treatment time did not affect the incidence of white spot formation. Among the bonded teeth that showed severe white spot formation (eight patients), the duration of bonding was not different from the remainder of the sample. This surprising observation may be tempered by the fact that no teeth were bonded or banded for less than 12 months. This may have provided sufficient time for the full effect of the adverse environmental factors to express themselves. The complete absence of any white spots associated with the lingual canine-to-canine retainer which had been in position for an average of 24 months was striking. It suggests that acid application during bonding does not, in itself, cause subsequent decalcification. It reinforces the concept that plaque accumulation associated with the inadequate hygiene on the labial surfaces frequently found among orthodontic patients is directly related to undesirable decalcifications, whether
98
Gorelick,
Geiger, and Gwinnett
the exposed tooth surface received an acid application or not. It is noted that the frequent accumulation of calculus on the lingual surfaces of the incisors along the wire of the canine-to-canine retainer resulted in no white spots. In our view, the data suggest that accessibility to the free flow of saliva may be a major factor in avoiding decalcification of enamel. Our clinical experience of little or no white spot formation after removal of bonded hooks on the lingual surfaces of maxillary and mandibular teeth supports this concept. The distribution of occurrence of white spots experienced in the bonded group strengthens this assumption. Maxillary molars and second premolars had significantly less decalcification than their mandibular opponents. The difference found in white spot incidence on maxillary central and lateral incisors, whether banded or bonded, suggests that small tooth surface areas between the gingiva and the bracket are conducive to the retention of plaque and debris. This suggests the desirability of bracket placement that leaves adequate distance in the labiogingival area for more efficient hygiene. Since more than 50 per cent of the patients studied exhibited no white spot formation, the potential influence of individual differences in enamel structure, composition of saliva, tooth brushing, and other variables remain questions to be investigated. Although the validity of a preventive fluoride regimen to avoid decalcification has not yet been established, Hirschfield’s” report is encouraging. As a continuation of our own work, an expedient fluoride program with bonding procedures has been designed and applied routinely in our practices. This report will provide a useful base line for comparison in evaluating data in the future. CONCLUSION
1. Decalcification of the labial (buccal) surfaces of teeth during orthodontic therapy is a problem of clinical
ilm. J. Orrhod. Fehruary~ 1982
importance, as shown by the finding that 3.6 per cent of the teeth had white spots in the control group and 10 per cent after treatment and that 50 per cent of the patients experienced an increase in white spots. 2. Certain teeth and tooth surfaces exhibit a predisposition to white spot formation. Access to the flow of saliva and the distance from bracket to free gingival margin are factors suggested by the data. 3. No differences were found between the frequency of white spots on the maxillary incisors that were bonded or banded. 4. Maxillary lateral incisors had three times as many white spots as maxillary central incisors, whether bonded or banded. 5. Teeth banded or bonded for a relatively short treatment interval (from 12 to 16 months) showed the same incidence of white spots as those involved in longer treatment (as long as 36 months). REFERENCES I. Darling, A. I.: Studies of the early carious lesion of enamel with transmitted light, polarized light and microradiography, Br. Dent. J. 101: 289-297, 1956. A. I.: Studies of the early lesion of enamel caries, Br. 2. Darling, Dent. J. 105: 119-135, 1958. 3. Gustafson, G.: The histopathology of caries of human dental enamel, Acta Odontol. Stand. 1.5: 13-55, 1957. 4. Hirshfield, R. E.: Control of decalcification by use of fluoride mouth rinse, J. Dent. Child. 45: 26-28, 1978. 5. Miller, W. D.: Die mikroorganismen des mundhohle, Leipzig, 1889. T.: Histologische untersuchungen fiber die anfange 6. Nishimura, der zahnkaries, speziell der karies des schmelzes, Schweiz. Monatsschr. Zahnheilkd. 36: 491-545, 1926. I. Poole, D. F. G.. Mortimer. K. V., Darling, A. I., and Ollis, W.: Molecular sieve behaviour of dental enamel, Nature 189: 9981000, 1961. 8. Silverstone, L. M.: Remineralization phenomena. Caries Res. 11: 59-84. 1977.
and A. John
Gwinnett***
White spots or areas of decalcification are carious lesions of varying extent. The incidence and severity of white spots after a full term of orthodontic treatment were studied among patients in the separate private practices of two of the authors. To establish a base line of comparison, the presence of white spots in a random sample of untreated persons was observed. The incidence of white spots among patients treated by a multibonded technique was recorded at the time of debonding. In addition, white spots were sought in the before- and after-treatment Kodachrome slides of persons whose maxillary incisors had been handed. It was found that individual teeth, banded or bonded, exhibited significantly more white spot formation than was found in the control group. For the teeth studied, there was no difference in white spot formation in those that were banded or bonded. The labiogingival area of the maxillary lateral incisors had the highest incidence of white spots, When studied by segments, the highest incidence occurred among the maxillary incisors; the lowest was in the maxillary posterior segment. No white spots were found on the lingual surfaces of mandibular canines and incisors after prolonged use of a canine-to-canine bonded retainer. These findings suggest a relationship between resistance to white spot formation and the rate of salivary flow. Despite the lack of any preventive fluoride program among the study groups, 50% of the patients demonstrated resistance to white spot formation, The obvious degree of iatrogenic damage during orthodontic treatment suggests the need for preventive programs using fluoride. Further clinical research is needed.
Key words: White spots, decalcification, caries resistance
iatrogenic,
E
name1 decalcification or white spot formation can occur whenever bacterial plaque is retained on the enamel surface for a prolonged period. The white spots caused by the decalcification (nondevelopmental) process can usually be differentiated from abnormal enamel calcification of developmental origin on the basis of location, shape, and dimensional stability with time, although when this developmental anomaly exists in the labiogingival area it may be confused with decalcification. Enamel decalcification has been identified in conjunction with orthodontic treatment. With the changes in technology which permit bonding rather than banding of teeth and the availability of preventive regimens, including fluoride, the frequency, prevention, and treatment of such iatrogenic damage have received renewed attention. *Staff Orthodontist, Long Island Jewish/Hillside Medical Center; Associate Professor, Department of Children’s Dentistry (Orthodontics), School of Dental Medicine, State University of New York at Stony Brook. **Associate Clinical Professor, School of Dental and Oral Surgery, Columbia University, New York, N. Y. ***Professor, Department of Oral Biology and Pathology, School of Dental Medicine, State University of New York at Stony Brook. 0002-9416/82/020093+06$00.60/0
0
1982 The C. V. Mosby Co.
bonding,
banding,
salivary flow, caries susceptibility,
The purpose of this article is to present the histopathologic characteristics of the lesion and clinical evidence addressed to the following questions: 1. What is the frequency of occurrence of white spot formation after full-term orthodontic treatment? 2. Is there a particular susceptibility of certain teeth to white spot formation? 3. Is the incidence and distribution of decalcification different if teeth are banded or bonded? 4. Does the duration of treatment significantly increase the risk of decalcification? Histopathology
of the white
spot
lesion.
Early enamel caries is manifested clinically as a white spot lesion. The appearance is caused by an optical phenomenon owing to subsurface tissue loss and is exaggerated by thorough drying. Evidence continues to mount in support of the acidogenic theory of caries5 which can involve the full thickness of enamel and extend well into dentin before cavitation begins. Since Nishimura’j first described the phenomenon of zonation in the early carious lesion, there have been several studies’-” detailing the structural features of enamel caries. 93
94
Gorelick,
Geiger, and Gwinnett
Fig. 1. A longitudinal ground section through an early carious lesion of enamel mounted in ethyl alcohol. In this polarized light photomicrograph the subsurface body of the lesion (B) and the dark zone (0) are well defined.
The zones in the lesion can be expressed in terms of spaces present” 7 or, conversely, tissue loss. Fig. 1 shows a section through an early enamel lesion. The first zone of histologic change is called the translucent zone. Here there is an absence of structural rod outlines and a tenfold increase in the amount of space compared to normal, unaffected enamel. Progressing into the lesion, the next zone is the dark or positive zone. The latter is named for its appearance in polarized light microscopy. This zone exhibits a further increase in the volume of spaces. It has been suggested’ that the translucent zone results from preferential dissolution of structure at the rod periphery, which then proceeds to the cross striations producing the dark zone. It has been shown,8 however, that remineralization occurs in the dark zone. Finally, the core of the rods is involved, producing a zone of maximum tissue destruction termed the body of the lesion. The outermost layer of enamel (that is, above the lesion) remains relatively intact and appears radiopaque in contact radiographs (Fig. 2). It is also a zone of remineralization.” This persistent layer has been explained on the basis of the interfacial chemistry between plaque and enamel. While there are several studies which report the successful remineralization of artificial carious lesions using calcifying media, there is a need for clinical research in this area. MATERIAL Direct examination
Child patients from the practices of two of us (L. G. and A. M. G.) were selected at random and examined for the presence of nondevelopmental white spots prior to the placement of any orthodontic Control
group.
Am. J. Orthod. February 1982
Fig. 2. A contact
microradiograph showing subsurface loss in an early enamel lesion with the surface enamel ing relatively intact.
mineral appear-
brackets or bands. This group of fifty children provided a base line of the expected incidence of white spots independent of any orthodontic procedures. Since this was a retrospective study group, strict comparisons with the treatment group were not intended. Bonded teeth. Patients in the practice of one of us (L. G.) were routinely examined for the presence of nondevelopmental white spots immediately yfrer removal of all bonded brackets. Of the 121 patients, forty-nine were boys and seveny-two were girls. All of these patients were children under 18 years of age who had worn bonded appliances for an average of 23.5 months. A total of 2,211 teeth were debonded and examined clinically for white spot formation. None of the patients was on a preventive fluoride program other than routine use of a fluoride toothpaste. Indirect
slide
examination-banded
teeth
From the records of one of the authors (A. G.), Kodachrome slides of the maxillary incisors taken before banding and after band removal were examined for white spot formation. Cases were selected at random. The photographs of seventy-one children (thirty-two boys, thirty-nine girls) were examined. In all, 280 teeth, which had been banded for an average of 26 months, were examined. Direct examination-bonded retainers
canine-to-canine
Patients who had worn bonded mandibular canineto-canine lingual retainers were recalled and observed clinically for white spot formation. Sixty children who had worn such retainers for an average of 24 months were examined.
White spot formation
Volume 81 Number 2
after bonding and banding
I. Frequency of white spot formation of untreated individual teeth
0 0n
Table
Percent affected
Tooth type Maxillary central incisor Maxillary lateral incisor Mandibular first molar Mandibular second premolar Maxillary first molar Mandibular first premolar Maxillary second premolar Mandibular central incisor Mandibular canine Maxillary canine Mandibular lateral incisor Maxillary first premolar
7.0 7.0 6.0 4.0 4.0 3.0 2.0 2.0 1.0 1.0 0.0 0.0
METHOD Direct examination
Clinical examination for the presence of white spots was made on the labial surface of individual teeth and, as shown in Fig. 3, the lesions were scored as follows: 1. No white spot formation. 2. Slight white spot formation. 3. Excessive white spot formation. 4. White spot formation with cavitation. In the group that had worn bonded metal orthodontic brackets, all teeth were examined immediately after debonding at the termination of orthodontic treatment and were scored as described. Indirect
slide
examination-banded
1 = None
2 = Slight
n
3 = Severe
4 = Cavitation Fig. 3. Schematic were
representation
95
of manner
l in which
the lesions
scored.
teeth
Patients whose maxillary incisors had been banded during orthodontic treatment were studied by means of before and after-treatment Kodachrome slides taken at the same angulation. The slides were projected and viewed on two separate occasions by two of us. The observations were completely consistent and reliable and were scored in the manner described above.
location of white spots related to orthodontic therapy. Of the total of 1,006 teeth examined, thirty-six (3.6 per cent) had slight white spot formation and none had excessive white spots or cavitation. Individual teeth with white spots were placed in order from the most to the least frequent, the distribution of which is seen in Table I.
After
Incidence
lingual
retainers
Those persons who had worn bonded lingual retainers were recalled for clinical inspection. Observations for decalcification were made not only of the lingual surfaces of the canines which had been bonded but also of the lingual surfaces of the incisors against which the retaining wire had rested. RESULTS Incidence
of white
spots-Control
group
Among the fifty children in the control group, twenty-seven were boys and twenty-three were girls. In twelve cases (24 per cent) at least one tooth had a nondevelopmental lesion that might be associated with the
of carious
white
spots-bonded
Of the entire sample of 121 patients who had been debonded, 49.6 per cent had white spot formation on at least one tooth. The incidence was 44 per cent for boys and 54 per cent for girls. Of the total of 2,211 teeth examined, however, only 10.8 per cent had white spots. In actuality, there was a large variation in the number of white spots per patient. Study of the frequency of white spots by segments (Table II) revealed that the highest percentage of incidence was found in the maxillary anterior and mandibular posterior segments 15.3 per cent and 14.1 per cent, respectively. The mandibular anterior (9.4 per cent) and maxillary posterior segments (4.5 per cent) exhib-
96
Gorelick,
Geiger,
and
Am. .I. Orrhod. Frhruun 1982
Gwinnett
II. Incidence of white spot formation by segments
Table
70-
6050-
Segment
No. oj teeth bonded
Incidence oj white spar (percent)
Mandibular molars and premolars Maxillary canines and incisors Mandibular canines and incisors Maxillary molars and premolars Total
491 686 650 384 2211
15.3 14.1 9.4 4.5 11.3
40-
Ill. Incidence of white spot formation by segments (right versus left)
Table
30-
Segments
I
i
o
6
! UPPER LOWER
1
No. teeth bonded
Incidence white spots average (%)
245 246
18.0 12.7
339 347
14.2 14.0
324 326
10.6 8.3
193 191
4.5 4.5
I
123456
LEFT
UPPER
RIGHT
LEFT
LOWER
RIGHT
Mandibular molars and premolars Right Left Maxillary canines and incisors Right Left Mandibular canines and incisors Right Left Maxillary molars and premolars Right Left
IV. Frequency of white spot formation of individual teeth (bonded group)
Table 60-
Tooth
7060901000
NONE 1
u
SLIGHT
2
SEVERE
3
Fig. 4. Histogram showing the frequency spots in each tooth in the dentition.
m
CAVITATION
4 and severity
of white
ited white spot formation less frequently. The difference between the most and least frequent was 10.8 per cent, significant at the 0.5 level. All segments were studied for differences in incidence of white spots between the right and left sides of the dentition (Table III). No differences were found
type
Maxillary lateral incisor Mandibular canine Mandibular first premolar Mandibular first molar Mandibular second premolar Maxillary canine Maxillary first premolar Maxillary central incisor Mandibular lateral incisor Maxillary second premolar Mandibular central incisor Maxillary first molar
Percent
affected 23.0 18.0 17.5 14.5 14.1 11.2 9.6 8.4 8.0 3.0 2.5 1.0
between the right and left sides in the maxilla. In the mandible, the right posterior segment and the left anterior segment showed a greater incidence than their contralateral sides. These findings were not significant. The frequency and severity of white spots for each tooth in the dentition are shown in the histogram (Fig.
White spotformation
Volume 81 Number 2
4). The highest incidence was found among the maxillary lateral incisors (23 per cent). The incidence for maxillary central incisors was 8.4 per cent, almost three times less than that found for the lateral incisors. The frequency of occurrence of white spots for individual teeth, when listed from the most to the least frequent, is shown in Table IV. The more severe white spots (recorded as 3 and 4 at clinical examination) were found in only eight patients, four boys and four girls, and involved only twelve teeth. Cavitation was found in seven teeth, involving the maxillary anterior teeth and mandibular molars. The average time that these teeth were bonded was 22 months. This time span was not different from the average bond time of the entire sample. Incidence
of carious
white
spots-banded
Of the 280 maxillary incisors studied from Kodachrome slides, 12 per cent showed some white spot formation after band removal. The incidence was 17 per cent for maxillary lateral incisors and 7 per cent for the central incisors. The average time span for the sample was 26 months. The distribution of the white spots found on the right and left sides was equal. The incidence of white spots was unrelated to the longevity of banding (minimum duration of banding, 12 months). There were nine teeth that exhibited more severe white spot formation. These were 4 per cent of the sample and, with the exception of one central incisor, were lateral incisors. The average time that these teeth were banded was not different from that of the entire sample. Incidence of white canine-to-canine
spots
with bonded
lingual
No white spot formation was found on the lingual surface of the mandibular bonded incisor or canines in any of the sixty patients recalled for this examination. Also, no decalcification was found on the lingual surfaces of nonbonded incisors, despite accumulations of stain and supragingival calculus alongside and beneath the retaining wire in many persons. DISCUSSION
Examination of the control group recorded white spots induced by plaque accumulation as well as those of developmental origin. This aspect of the study was undertaken to provide a clinical description of the incidence of white spots on the labial surfaces of teeth in a random population prior to any orthodontic procedures. The maxillary incisors and the mandibular molars and second premolars had the highest incidence of white spot formation (about 7 per cent).
after
bonding and banding 97
In the group whose teeth had been bonded, study by segments showed that the mandibular posterior (15 per cent) and maxillary anterior (14 per cent) teeth had the highest incidence of white spot formation. The marked increase in white spots in these segments over that found in the control group was consistent for all other segments, but in varying degrees. Study by right and left sides of the dentition and maxillary and mandibular arches showed no consistent associations in the distribution of white spots. The incidence of white spots after debonding was reviewed for individual teeth (Table IV). The maxillary lateral incisors had the highest incidence of decalcification (21 per cent), which was almost three times as frequent as that found for the central incisors. The maxillary and mandibular canines and premolars had a high incidence of white spots and, when related to the control group, the increase for these teeth was disproportionately high. The incidence of white spots for the mandibular molars was more consistent with the incidence in the control group. The maxillary molars, on the other hand, showed no differences between the bonded and control groups. The photographic observation of teeth that had been banded was restricted to the maxillary incisors. The maxillary lateral incisors experienced white spot formation most frequently (17 per cent), about two and one-half times as frequently as the central incisors (Table IV). Hirschfield” reported a 33 per cent incidence of white spots for thirty banded right maxillary lateral incisors. Comparison of the incidence of the maxillary incisors of the banded group with those of the bonded group shows a similarity of experience, and both groups clearly showed more decalcification than the control group. In both the banded and the bonded groups the length of treatment time did not affect the incidence of white spot formation. Among the bonded teeth that showed severe white spot formation (eight patients), the duration of bonding was not different from the remainder of the sample. This surprising observation may be tempered by the fact that no teeth were bonded or banded for less than 12 months. This may have provided sufficient time for the full effect of the adverse environmental factors to express themselves. The complete absence of any white spots associated with the lingual canine-to-canine retainer which had been in position for an average of 24 months was striking. It suggests that acid application during bonding does not, in itself, cause subsequent decalcification. It reinforces the concept that plaque accumulation associated with the inadequate hygiene on the labial surfaces frequently found among orthodontic patients is directly related to undesirable decalcifications, whether
98
Gorelick,
Geiger, and Gwinnett
the exposed tooth surface received an acid application or not. It is noted that the frequent accumulation of calculus on the lingual surfaces of the incisors along the wire of the canine-to-canine retainer resulted in no white spots. In our view, the data suggest that accessibility to the free flow of saliva may be a major factor in avoiding decalcification of enamel. Our clinical experience of little or no white spot formation after removal of bonded hooks on the lingual surfaces of maxillary and mandibular teeth supports this concept. The distribution of occurrence of white spots experienced in the bonded group strengthens this assumption. Maxillary molars and second premolars had significantly less decalcification than their mandibular opponents. The difference found in white spot incidence on maxillary central and lateral incisors, whether banded or bonded, suggests that small tooth surface areas between the gingiva and the bracket are conducive to the retention of plaque and debris. This suggests the desirability of bracket placement that leaves adequate distance in the labiogingival area for more efficient hygiene. Since more than 50 per cent of the patients studied exhibited no white spot formation, the potential influence of individual differences in enamel structure, composition of saliva, tooth brushing, and other variables remain questions to be investigated. Although the validity of a preventive fluoride regimen to avoid decalcification has not yet been established, Hirschfield’s” report is encouraging. As a continuation of our own work, an expedient fluoride program with bonding procedures has been designed and applied routinely in our practices. This report will provide a useful base line for comparison in evaluating data in the future. CONCLUSION
1. Decalcification of the labial (buccal) surfaces of teeth during orthodontic therapy is a problem of clinical
ilm. J. Orrhod. Fehruary~ 1982
importance, as shown by the finding that 3.6 per cent of the teeth had white spots in the control group and 10 per cent after treatment and that 50 per cent of the patients experienced an increase in white spots. 2. Certain teeth and tooth surfaces exhibit a predisposition to white spot formation. Access to the flow of saliva and the distance from bracket to free gingival margin are factors suggested by the data. 3. No differences were found between the frequency of white spots on the maxillary incisors that were bonded or banded. 4. Maxillary lateral incisors had three times as many white spots as maxillary central incisors, whether bonded or banded. 5. Teeth banded or bonded for a relatively short treatment interval (from 12 to 16 months) showed the same incidence of white spots as those involved in longer treatment (as long as 36 months). REFERENCES I. Darling, A. I.: Studies of the early carious lesion of enamel with transmitted light, polarized light and microradiography, Br. Dent. J. 101: 289-297, 1956. A. I.: Studies of the early lesion of enamel caries, Br. 2. Darling, Dent. J. 105: 119-135, 1958. 3. Gustafson, G.: The histopathology of caries of human dental enamel, Acta Odontol. Stand. 1.5: 13-55, 1957. 4. Hirshfield, R. E.: Control of decalcification by use of fluoride mouth rinse, J. Dent. Child. 45: 26-28, 1978. 5. Miller, W. D.: Die mikroorganismen des mundhohle, Leipzig, 1889. T.: Histologische untersuchungen fiber die anfange 6. Nishimura, der zahnkaries, speziell der karies des schmelzes, Schweiz. Monatsschr. Zahnheilkd. 36: 491-545, 1926. I. Poole, D. F. G.. Mortimer. K. V., Darling, A. I., and Ollis, W.: Molecular sieve behaviour of dental enamel, Nature 189: 9981000, 1961. 8. Silverstone, L. M.: Remineralization phenomena. Caries Res. 11: 59-84. 1977.