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The effect of fixed and functional appliances on enamel decalcifications in early Class II treatment
The effect of fixed and functional appliances on enamel decalcifications in early Class II treatment Stanley A. Alexander, DMD* Stony Brook, N.Y. The presence of enamel decalcifications before and after early Class II treatment was examined on 41 subjects and 164 permanent first molars. No new demineralization areas were found in patients wearing only a removable appliance. Of the maxillary molars 6% displayed decalcifications in patients wearing a headgear only: whereas of patients wearing a headgear and biteplate 25% displayed enamel lesions. Eighteen percent of white spot lesions diagnosed before treatment had shown a "reversal phenomenon," whereby the enamel appeared normal after treatment. This process only occurred in the functional appliance group indicating that remineralization was better achieved with an appliance that was capable of being removed from the oral cavity. (AMJ ORTHOD DENTOFAC ORTHOP 1993;103:45-7.)"
I n the environment in which they function, all orthodontic appliances have the potential to damage enamel either by decalcification or by ~aries. t-~ White spot lesions or decalcifications are early manifestations o f the carious process resulting from subsurface demineralization2 7 The acids involved in this process are produced by plaque colonies on either the dentition or associated appliances during the ingestion of fermentable carbohydrates. The presence o f orthodontic appliances may hamper the removal o f plaque even by the most conscientious oral hygiene advocate and may contribute to these enamel lesions, s-9 No studies have specifically reported enamel conditions in young patient populations treated with fixed versus removable appliances. It was therefore the purpose o f this study to observe the differences, if any, of healthy enamel in the early treatment of patients with Class II malocclusions.
MATERIALS AND METHODS Forty-one subjects (24 girls and 17 boys) between the ages of 9 and l I years participated in the study. All were in good medical health with Class II, Division 1 malocclusions. The dental overbite relationships were either normal or deep impinging overbites. After a complete orthodontic evaluation, these patients fell within the c~tegory of mandibular retrognathia. On the basis of their clinical findings, itwas determined that these patients would be treated with either a func"tional appliance to advance the mandible, a cervical headgear alone, or headgear and anterior biteplate combination to allow for mandibular growth while inhibiting forward growth of the
From the Department of Orthodontics,,. College of Dentistr)', University of WcnllcSSCr 0889-5406/93/S1.00 + 0.10
8/I/32934
maxilla. The decision for appliance type was given to the patient based on projected compliance. Sixteen patients chose functional appliances (bionator type), 17 patients chose cervical headgear, and 8 patients chose the headgear removable anterior biteplate combination. Within these categories, a total of 82 maxillary permanent first molars and 82 mandibular permanent first molars were examined for buccal or lingual decalcifications before appliance placement. Lesions were noted to be either present or absent according to descriptions by Gorelick and co-workers~ and were measured with needle calipers to determine their area of involvement. No evaluation for decalcification or enamel defects of the erupting canines or premolars was undertaken due to the various stages of the eruption sequence for these patients. Although no fixed appliance was placed on the mandibular dentition, it was believed that these teeth should be evaluated in the study because of the positioning of the functional appliance. Of the 164 molars examined before treatment, 17 maxillary molars and 6 mandibular molars exhibited white spot lesions either of developmental origin or induced by plaque accumulation. Of these 23 lesions, 9 werepresent in the boys and 14 in the girls. Twenty lesions were present on buccal surfaces, whereas three appeared on lingual surfaces. Lingual lesions were only present on the mandibular teeth. These lesions covered an average area of 6 mm 2 with a range from 4 to 7 nun 2, all located along the gingival margins of the affected teeth. Measurements were obtained with needle calipers and then transferring the caliper diameter to a millimeter ruler, rounding off to the nearest 0.5 mm. These lesions were then charted on the patient's record. No tooth exhibited more than one continuous lesion. No restorations were present, or other cavitations observed. Two weeks before appliance placement, patients and parents were instructed with a conventional oral hygiene method using a horizontal scrub technique with fluoridated toothpaste. The patients were instructed in no other form of cleaning. All patients rinsed daily with 0.05% acidulated sodium fluoride 45
46
Am. J. Orthod.Dentofac. Orthop. January 1993
Alexander
Table I. Incidence of white spot formation of permanent first molars treated with fixed and functional appliances
I
No. of teeth examined
Percent of teeth with decalcificatiot,
164 82
14% 0%
Presence of white spots before treatment (N = 23) White spots present on mandibular molars after treatment (N = 0)
Table II. New white spot lesions present after treatment on maxillary molars
Group Bionator Headgear Headgear and anterior biteplate
I
Lesions 0 2* 4*
I
No lesions 32 32 12
*Chi square value, p < 0.01.
solutions throughout the treatment period and received biannual professionally applied topical fluoride treatments. Seventeen maxillary molars and six mandibular molars exhibited decalcifications before treatment. Seven of the 17 subjects were treated with appliances cemented to their maxillary molars, (6 buccal lesions, 1 lingual lesion). Five subjects were treated with a combination of cemented appliances and anterior biteplates (4 buccal lesions, 2 lingual lesions), whereas the other five subjects were treated with bionators (10 buccal lesions). All maxillary molar bands were cemented with glass ionomer cement (Shofu lnc: Kyoto, Japan) and checked for washout or looseness at each 4-week visit. Although band adaptation indicated no exposed cement margins, none of the bands appeared loose during the treatment period. The anterior biteplate was a typical design, with circumferential clasps placed gingival to the band tubes and extended to the second premolar margins. The bionator design was the standard form to gain correction in the anteroposterior direction and to achieve bite opening. The functional appliance group received treatment for 14 --- 2 months, whereas the fixed appliance group with or without an anterior biteplate had undergone treatment for 12 + 4 months. Each patient was instructed to wear the appliance a minimum of 14 hours daily. Active treatment was discontinued once an overcorrected Class I molar relationship and a normal overbite ~vas achieved. RESULTS Of the 82 mandibular teeth examined, no new white spot lesions were detected after the treatment period. The 17 preexisting decalcifications were reduced to 14 as a result of white spot reversals to normal enamel conditions in the bionator group. No reversals were apparent in the fixed appliance groups. Of the remaining 65 maxillary molars with normal enamel, six were
found to display white spot lesions on the buccal surfaces after debanding. This represented a 9% overall decalcification rate. Four of the six teeth with decalcifications occurred in the group with combined headgear and biteplate therapy. Of these six new lesions, two had a prior lesion present on the opposite side of the arch. No new decalcifications were found in the group receiving treatment with the functional appliance (Table I). Chi square tests between the functional appliance group and fixed appliance groups showed that the prevalence of enamel lesions was significant (p < 0.01) between the two methods of treatment (Table II). DISCUSSION It is a logical assumption to predict a decreased risk of decalcification or caries when removable appliances are compared with conventional fixed mechanisms, 1~ and similar oral hygiene methods have been instituted. In this study, the incidence of decalcification with banded appliances (headgear alone or headgear and biteplate combination) was 9%, or twice the incidence of previous reports. 8 No new decalcification areas were observed within the bionator group. Since the groups initially did not display a relatively higher incidence of decalcifications, they therefore were not prone to more new lesions. Although the incidence of white spot lesions in the sample population was high and other factors can play a role in the caries process other than appliance design, the young ages o f these patients may have also contributed to the higher percentage of postoperative lesions observed because of dexterity and cooperation. Although treatment time averaged between 12 to 14 months, a significantly shorter time period than tradiiional comprehensive care, this younger age group may display less oral hygiene compliance when compared with older patients undergoing orthodontic treatment. Of the six patients who displayed decalcifications after treatment, it was interesting to observe that four of the six patients were within the group that wore both a fixed and a removable appliance (headgear and biteplate). It is likely that the combination and positioning of appliances circumscribing the maxillary first molar area creates an environment that is more
Volume 103 Number 1
Effect of fLred and functional appliances on decalcification
47
prone to decalcification when compared with strictly removable or singular appliances, such as only a headgear attached to molar bands. Although only six new decalcified surfaces were observed in the 65 healthy maxillary molars, it is apparent that a certain percentage of teeth are at risk during treatment with fixed appliances. Interestingly, 18% of white spot lesions diagnosed before treatment had shown a "reversal" to normal enamel anatomy. Reports of this phenomenon H~2 are as high as 51% of enamel lesions returning to clinically sound conditions after 7 years in an untreated population. The lower number of reversals encountered here may imply that plaque retentive areas found in fixed appliances when compared with removable appliances may seriously jeopardize the remineralization process. It is also possible that the lower percentage of "reversals" seen was due to a short treatment period that does not allow the remineralization process to fully express itself. Nevertheless, it appears that when early treatment is recommended and when a fixed appliance is used for this correction, a small percentage of patients will experience demineralization phenomena.
3. Chatterjee R, Kleinberg I. Effect of orthodontic band placement on the chemical composition of human incisor tooth plaque. Arch Oral Biol 1979;24:97-100. 4. Scheie AA, Arnesberg P, Krogstad O. Effects of orthodontic treatment on prevalence of Streptococcus mutans in plaque and "saliva. Scand J Dent Res 1984;92:211-7. 5. Darling AI. Studies of the early carious lesion of enamel with transmitted light, polarized light, and microradiography. Br Dent J 1956;101:289-97. 6. Poole DFG, Mortimer KV, Darling AI, Ollis W. Molecular sieve behaviour of dental enamel. Nature 1961;189:998-1000. 7. Mizrahi E. Enamel demineralization following orthodontic treatment. AM J ORTttOD 1982;82:62-7. 8. Gorelick L, Geiger AM, Gwinnett AJ. Incidence of white spot formation after banding and bonding. Ar,t J ORTHOO 1982;81: 93-8. 9. Mihalow DM, Tinanoff N. The influence of removable partial dentures on the levels of Streptococcus mutans in saliva. J Prosthet Dent 1988;59:49-51. 10. King GJ, Keeling SD, Hocevar RA, Wheeler TT. The timing of treatment for Class I1 malocclusions in children: a literature review. Angle Orthod 1990;6:87-97. I1. Backer-Dirks O. Posteruptive changes in dental enamel. J Dent Res 1966;45:503-11. 12. O'Reilly MM, Featherstone JD. Demineralization and remineralization around orthodontic appliances: an in vivo study. AM J ORTItOD DENTOFACORTtIOP 1987;92:33-40.
REFERENCES 1. Balenseifen JW, Madonia JV. Study of dental plaque in ortfiodontic patients. J Dent Res 1970;49:20-3. 2. Zachfisson BU, Zachrisson S. Caries incidence and orthodontic treatment with fixed appliances. Scand J Dent Res 1971;79:183o 92.
Reprint requests to: Dr. Stanley A. Alexander Postgraduate Orthodontics School of Dental Medicine SUNY at Stony Brook Stony Brook, NY 11794-8701
I n the environment in which they function, all orthodontic appliances have the potential to damage enamel either by decalcification or by ~aries. t-~ White spot lesions or decalcifications are early manifestations o f the carious process resulting from subsurface demineralization2 7 The acids involved in this process are produced by plaque colonies on either the dentition or associated appliances during the ingestion of fermentable carbohydrates. The presence o f orthodontic appliances may hamper the removal o f plaque even by the most conscientious oral hygiene advocate and may contribute to these enamel lesions, s-9 No studies have specifically reported enamel conditions in young patient populations treated with fixed versus removable appliances. It was therefore the purpose o f this study to observe the differences, if any, of healthy enamel in the early treatment of patients with Class II malocclusions.
MATERIALS AND METHODS Forty-one subjects (24 girls and 17 boys) between the ages of 9 and l I years participated in the study. All were in good medical health with Class II, Division 1 malocclusions. The dental overbite relationships were either normal or deep impinging overbites. After a complete orthodontic evaluation, these patients fell within the c~tegory of mandibular retrognathia. On the basis of their clinical findings, itwas determined that these patients would be treated with either a func"tional appliance to advance the mandible, a cervical headgear alone, or headgear and anterior biteplate combination to allow for mandibular growth while inhibiting forward growth of the
From the Department of Orthodontics,,. College of Dentistr)', University of WcnllcSSCr 0889-5406/93/S1.00 + 0.10
8/I/32934
maxilla. The decision for appliance type was given to the patient based on projected compliance. Sixteen patients chose functional appliances (bionator type), 17 patients chose cervical headgear, and 8 patients chose the headgear removable anterior biteplate combination. Within these categories, a total of 82 maxillary permanent first molars and 82 mandibular permanent first molars were examined for buccal or lingual decalcifications before appliance placement. Lesions were noted to be either present or absent according to descriptions by Gorelick and co-workers~ and were measured with needle calipers to determine their area of involvement. No evaluation for decalcification or enamel defects of the erupting canines or premolars was undertaken due to the various stages of the eruption sequence for these patients. Although no fixed appliance was placed on the mandibular dentition, it was believed that these teeth should be evaluated in the study because of the positioning of the functional appliance. Of the 164 molars examined before treatment, 17 maxillary molars and 6 mandibular molars exhibited white spot lesions either of developmental origin or induced by plaque accumulation. Of these 23 lesions, 9 werepresent in the boys and 14 in the girls. Twenty lesions were present on buccal surfaces, whereas three appeared on lingual surfaces. Lingual lesions were only present on the mandibular teeth. These lesions covered an average area of 6 mm 2 with a range from 4 to 7 nun 2, all located along the gingival margins of the affected teeth. Measurements were obtained with needle calipers and then transferring the caliper diameter to a millimeter ruler, rounding off to the nearest 0.5 mm. These lesions were then charted on the patient's record. No tooth exhibited more than one continuous lesion. No restorations were present, or other cavitations observed. Two weeks before appliance placement, patients and parents were instructed with a conventional oral hygiene method using a horizontal scrub technique with fluoridated toothpaste. The patients were instructed in no other form of cleaning. All patients rinsed daily with 0.05% acidulated sodium fluoride 45
46
Am. J. Orthod.Dentofac. Orthop. January 1993
Alexander
Table I. Incidence of white spot formation of permanent first molars treated with fixed and functional appliances
I
No. of teeth examined
Percent of teeth with decalcificatiot,
164 82
14% 0%
Presence of white spots before treatment (N = 23) White spots present on mandibular molars after treatment (N = 0)
Table II. New white spot lesions present after treatment on maxillary molars
Group Bionator Headgear Headgear and anterior biteplate
I
Lesions 0 2* 4*
I
No lesions 32 32 12
*Chi square value, p < 0.01.
solutions throughout the treatment period and received biannual professionally applied topical fluoride treatments. Seventeen maxillary molars and six mandibular molars exhibited decalcifications before treatment. Seven of the 17 subjects were treated with appliances cemented to their maxillary molars, (6 buccal lesions, 1 lingual lesion). Five subjects were treated with a combination of cemented appliances and anterior biteplates (4 buccal lesions, 2 lingual lesions), whereas the other five subjects were treated with bionators (10 buccal lesions). All maxillary molar bands were cemented with glass ionomer cement (Shofu lnc: Kyoto, Japan) and checked for washout or looseness at each 4-week visit. Although band adaptation indicated no exposed cement margins, none of the bands appeared loose during the treatment period. The anterior biteplate was a typical design, with circumferential clasps placed gingival to the band tubes and extended to the second premolar margins. The bionator design was the standard form to gain correction in the anteroposterior direction and to achieve bite opening. The functional appliance group received treatment for 14 --- 2 months, whereas the fixed appliance group with or without an anterior biteplate had undergone treatment for 12 + 4 months. Each patient was instructed to wear the appliance a minimum of 14 hours daily. Active treatment was discontinued once an overcorrected Class I molar relationship and a normal overbite ~vas achieved. RESULTS Of the 82 mandibular teeth examined, no new white spot lesions were detected after the treatment period. The 17 preexisting decalcifications were reduced to 14 as a result of white spot reversals to normal enamel conditions in the bionator group. No reversals were apparent in the fixed appliance groups. Of the remaining 65 maxillary molars with normal enamel, six were
found to display white spot lesions on the buccal surfaces after debanding. This represented a 9% overall decalcification rate. Four of the six teeth with decalcifications occurred in the group with combined headgear and biteplate therapy. Of these six new lesions, two had a prior lesion present on the opposite side of the arch. No new decalcifications were found in the group receiving treatment with the functional appliance (Table I). Chi square tests between the functional appliance group and fixed appliance groups showed that the prevalence of enamel lesions was significant (p < 0.01) between the two methods of treatment (Table II). DISCUSSION It is a logical assumption to predict a decreased risk of decalcification or caries when removable appliances are compared with conventional fixed mechanisms, 1~ and similar oral hygiene methods have been instituted. In this study, the incidence of decalcification with banded appliances (headgear alone or headgear and biteplate combination) was 9%, or twice the incidence of previous reports. 8 No new decalcification areas were observed within the bionator group. Since the groups initially did not display a relatively higher incidence of decalcifications, they therefore were not prone to more new lesions. Although the incidence of white spot lesions in the sample population was high and other factors can play a role in the caries process other than appliance design, the young ages o f these patients may have also contributed to the higher percentage of postoperative lesions observed because of dexterity and cooperation. Although treatment time averaged between 12 to 14 months, a significantly shorter time period than tradiiional comprehensive care, this younger age group may display less oral hygiene compliance when compared with older patients undergoing orthodontic treatment. Of the six patients who displayed decalcifications after treatment, it was interesting to observe that four of the six patients were within the group that wore both a fixed and a removable appliance (headgear and biteplate). It is likely that the combination and positioning of appliances circumscribing the maxillary first molar area creates an environment that is more
Volume 103 Number 1
Effect of fLred and functional appliances on decalcification
47
prone to decalcification when compared with strictly removable or singular appliances, such as only a headgear attached to molar bands. Although only six new decalcified surfaces were observed in the 65 healthy maxillary molars, it is apparent that a certain percentage of teeth are at risk during treatment with fixed appliances. Interestingly, 18% of white spot lesions diagnosed before treatment had shown a "reversal" to normal enamel anatomy. Reports of this phenomenon H~2 are as high as 51% of enamel lesions returning to clinically sound conditions after 7 years in an untreated population. The lower number of reversals encountered here may imply that plaque retentive areas found in fixed appliances when compared with removable appliances may seriously jeopardize the remineralization process. It is also possible that the lower percentage of "reversals" seen was due to a short treatment period that does not allow the remineralization process to fully express itself. Nevertheless, it appears that when early treatment is recommended and when a fixed appliance is used for this correction, a small percentage of patients will experience demineralization phenomena.
3. Chatterjee R, Kleinberg I. Effect of orthodontic band placement on the chemical composition of human incisor tooth plaque. Arch Oral Biol 1979;24:97-100. 4. Scheie AA, Arnesberg P, Krogstad O. Effects of orthodontic treatment on prevalence of Streptococcus mutans in plaque and "saliva. Scand J Dent Res 1984;92:211-7. 5. Darling AI. Studies of the early carious lesion of enamel with transmitted light, polarized light, and microradiography. Br Dent J 1956;101:289-97. 6. Poole DFG, Mortimer KV, Darling AI, Ollis W. Molecular sieve behaviour of dental enamel. Nature 1961;189:998-1000. 7. Mizrahi E. Enamel demineralization following orthodontic treatment. AM J ORTttOD 1982;82:62-7. 8. Gorelick L, Geiger AM, Gwinnett AJ. Incidence of white spot formation after banding and bonding. Ar,t J ORTHOO 1982;81: 93-8. 9. Mihalow DM, Tinanoff N. The influence of removable partial dentures on the levels of Streptococcus mutans in saliva. J Prosthet Dent 1988;59:49-51. 10. King GJ, Keeling SD, Hocevar RA, Wheeler TT. The timing of treatment for Class I1 malocclusions in children: a literature review. Angle Orthod 1990;6:87-97. I1. Backer-Dirks O. Posteruptive changes in dental enamel. J Dent Res 1966;45:503-11. 12. O'Reilly MM, Featherstone JD. Demineralization and remineralization around orthodontic appliances: an in vivo study. AM J ORTItOD DENTOFACORTtIOP 1987;92:33-40.
REFERENCES 1. Balenseifen JW, Madonia JV. Study of dental plaque in ortfiodontic patients. J Dent Res 1970;49:20-3. 2. Zachfisson BU, Zachrisson S. Caries incidence and orthodontic treatment with fixed appliances. Scand J Dent Res 1971;79:183o 92.
Reprint requests to: Dr. Stanley A. Alexander Postgraduate Orthodontics School of Dental Medicine SUNY at Stony Brook Stony Brook, NY 11794-8701