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Effect of Early Class II Treatment on the Incidence of Incisor Trauma


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1 EFFECT OF EARLY CLASS II TREATM ENT ON THE INCIDE NCE OF INCISOR TRAUMA By DAVID RUEY CHEN A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2007

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2 2007 David Ruey Chen

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3 ACKNOWLEDGMENTS I thank the members of my supervisory comm ittee, for their mentoring; my family and friends, for their continual support and encouragement.

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4 TABLE OF CONTENTS page ACKNOWLEDGMENTS...............................................................................................................3 LIST OF TABLES................................................................................................................. ..........5 LIST OF FIGURES................................................................................................................ .........6 ABSTRACT....................................................................................................................... ..............7 CHAPTER 1 INTRODUCTION................................................................................................................... .9 2 MATERIALS AND METHODS...........................................................................................11 Subjects....................................................................................................................... ............11 Inclusion Criteria............................................................................................................. .......11 Methods........................................................................................................................ ..........11 Data Analysis.................................................................................................................. ........12 3 RESULTS........................................................................................................................ .......14 4 DISCUSSION..................................................................................................................... ....21 5 CONCLUSIONS....................................................................................................................24 LIST OF REFERENCES............................................................................................................. ..25 BIOGRAPHICAL SKETCH.........................................................................................................28

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5 LIST OF TABLES Table page 3-1 Subject characteristics by treatment group........................................................................16 3-2 Incidence of incisor in jury (maxillary incisors).................................................................16

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6 LIST OF FIGURES Figure page 2-1 Modified Ellis Classification.............................................................................................13 3-1 Maxillary incisor injury distribution and severity.............................................................17 3-2 Mandibular incisor injury distribution and severity...........................................................18 3-3 Incidence of injury in males vs. fe males throughout treatment. = P < 0.05...................19 3-4 Incidence of injury in sex between treatment groups from DC1-F (maxillary incisors). = P < 0.05........................................................................................................20

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7 Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science EFFECT OF EARLY CLASS II TREATM ENT ON THE INCIDE NCE OF INCISOR TRAUMA By David Ruey Chen May 2007 Chair: Calogero Dolce Major: Dental Sciences Many studies have demonstrated the freque ncy of dental injuri es in children and adolescents. The purpose of this study was to evaluate the prevalence and the effect on incidence of incisor trauma in pa tients that participated in a clin ical trial designed to investigate early growth modifications in th e treatment of CLII malocclusion. The subjects were categorized into 3 groups based on the type of treatment duri ng phase-1: (1) headgear/b iteplane, (2) bionator, (3) no treatment observation group. All 3 groups underwent phase-2 treatment with fixed appliances. Incisor injury was scored at ever y data collection point w ith the Ellis index by a single-blinded examiner using dental casts, intr aoral photos, panoramic and periapical x-rays. Twenty-five percent of the subjec ts had some level of incisor trauma at baseline exam. No significant differences were found in regards to sex and prevalen ce of injury at baseline, but males did show higher incidence of injury throughout the course of treatment. No differences in incidence of trauma were found between the 3 gr oups throughout treatment. The majority of the injuries were minor and consisted of enamel fr actures only (80%). Sevent y-eight percent of the injuries occurred in the maxillary incisors with central incisors bei ng the most common. Early orthodontic treatment does not seem to affect the incidence of inci sor injury. The majority of the

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8 injuries prior to and during treatment were minor therefore the cost bene fit ratio of orthodontic treatment in order to prevent incisor trauma is doubtful.

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9 CHAPTER 1 INTRODUCTION Dental injuries are common and present an important dental public health problem. Many epidemiological studies during the last thr ee decades have shown the frequency of dental injuries in children and adolescents.1-8 The occurrence of dental in juries in a population can be defined by its prevalence and incidence. The pr evalence of incisor injury has been reported to range from 6% to 34%.9-11 Falls, collisions, sporting activitie s, and traffic accidents have been reported to be the main cause of most dental injuries.12,13 Variables such as age, gender, socioeconomic status, and behavioral problems may al so influence the frequency of dental trauma. Bauss et al.12 and Caliskan et al.13 both found that patients ag ed 8 years exhibited the highest prevalence of dental tr auma. It has been shown that incisor injuries occur more frequently in males.14,15 Socio-economic influences can al so have a significant effect on a childs experience with dental injuries.16,17 Studies have shown a positive correlation between the frequency of incisor trau ma with increased protrusion,18,19 Class II malocclusion,3,20 increased overjet,21-24 and lip incompetence.19,25 Early orthodontic treatment for children with such characteristics has been recommended in order to prevent incisor trauma and its sequelae.22,25 Nguyen et al.23 had suggested the incorporation of overjet as a malocclusion item into orthodontic treatmen t indices because of its potential correlation with dental trauma. Although the indications for early orthodontic treatment in order to diminish the likelihood of trauma to permanent incisors have been presented by several authors, Koroluk et al.26 found the majority of injuries to be minor and easily treated at low cost and with good long-term prognosis. They concluded that early growth modifica tion might have some effect on the incidence of trauma but the expected cost of trauma per child to be less for those who had a 2-phase orthodontic treatment.

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10 The efficacy of early intervention is largel y dependent on the timing of treatment and peak occurrence of injury. Orthodontic intervention could be ineffective with minimal benefits if dental trauma occurs before the start of treatme nt. Currently, few reports are available regarding the effectiveness of early ort hodontic treatment in order to re duce the incidence of incisor trauma. The purpose of this study was to evaluate th e prevalence and the effect on incidence of incisor trauma in patients that participated in a clinical trial designed to investigate early growth modifications in the treatment of CLII malocclusion.

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11 CHAPTER 2 MATERIALS AND METHODS Subjects The subjects were part of a previous prosp ective, longitudinal, ra ndomized clinical trial designed to examine and report the effectiveness of early treatment with headgear/biteplane (HG/BP) or with bionator (B) in patients with Class II malocclusion and compare results with changes over a similar time period in an observati on (C) group. A stratified block randomization procedure was used to assign a treatment prot ocol (HG/BP, B, C) during Phase-1 for each patient. Strata were defined by severity of Cla ss II malocclusion, need for preparatory treatment, mandibular plane angle, race, and gender. Af ter completing Phase-1, all groups underwent fixed appliances in Phase-2, followed by a retentio n/follow-up period. The study design and subject selection are described in detail in the previous publication.27 Inclusion Criteria The inclusion criteria included: bilateral great er than or equal to one-half-cusp Class II molars, or unilateral greater than one-half-cusp Class II molars, fully erupted permanent first molars, not more than 3 permanent canines or premolars, positive overjet and overbite, and good general and dental health. Methods Incisor injury was assessed at all data co llection (DC) points usi ng the Modified Ellis Classification (Figure 2-1). Ma xillary (#7) and mandibular ( #23) incisors were scored. Study models, intraoral/extraoral photos, x-rays (lateral cephlogr am, panoramic, and periapicals taken during Phase-2) obtained at each DC point was used to insp ect incisor injury. Any existing or new restorations on each tooth were noted. On e trained and reliability tested examiner [DRC]

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12 recorded all injuries. The records for all DC poi nts of each patient were evaluated at the same time in order to eliminate the chance of recording errors over time. Overjet was assessed for each patient at al l DC points using the lateral cephalograms taken at each data collection period. Data Analysis Statistical comparisons were performed at baseline (DC 1), end of Phase 1 (DC 5), baseline at Phase 2 (DC 7), and end of Phase 2 (DC F). Relationships between outcomes and covariates were examined with chi-square and Fish er exact tests. For a ll analyses, a p-value less than 0.05 was considered statistically significant. Pearsons correlation coefficient was used to examine any relationship between initial overjet and trauma.

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13 Score Injury Description 0 Non injured tooth 1 Fracture of the crown involving enamel only 2 Fracture of the crown involving enamel and dentin 3 Fracture of crown involving pulp (untreated, pulp cap, pulpotomy, root filling) 4 Nonvital without crown fracture 5 Root fracture 6 Lost due to trauma 7 Missing tooth Figure 2-1. Modified Ellis Classification.

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14 CHAPTER 3 RESULTS Table 3-1 presents the subject char acteristics by treatment gr oup. At DC 1, 64 of the 261 participants (25%) had some level of incisor trauma (B=27 (31%), HG/BP=18 (19%) C=19 (23%)). The differences in the distribution of subjects with trauma to each treatment group were not statistically sign ificant (P = 0.18). Figures 3-1 and 3-2 shows the distributi on and severity of injury to maxillary and mandibular teeth. The majo rity (80%) of the injuries were scored as a minor fractures involving enamel only. Fractures involving enamel and dentin consisted of 19% and only 1 subject had trauma w ith pulpal exposure. The maxill ary incisors had the highest number of injuries (77%), with central inciso rs being the most common. The prevalence of incisor trauma at DC 1 were not statistically signif icant between males and females (P = 0.27), with 21% of females and 27% of males having some degree of incisor trauma. Since the majority of the injuries occurred in the maxilla, further analysis focused on the incidence of only maxillary incisor injury. As shown in Table 3-2, there were no differences in the incidence of new trauma between trea tment groups during phase-1 (DC1), between treatment phases (DC5), during phase-2 (DC7F), and overall (DC1F). As seen in Figure 3-3, there was a statistically significant higher incidence of trauma in males compared with females during the entire study. During the entire course of the study, only the control group and not the HG/BP or bionator groups showed a statistic ally significant higher incidence of trauma in males than females (Figure 3-4). Overjet was measured to determine if overjet correl ated with trauma in males. The mean overjet value at baseline was 5.81mm ( 2.77 SD ; range, 0.87.2) for males and 5.48mm ( 2.30 SD; range, 0.51.2) for females. No correla tion was found between in itial overjet value and amount of upper incisor trau ma at baseline (Pearson Correl ation Coefficient = 0.02; P =

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15 0.75). When evaluating baseline overjet and ch ange in upper incisor in jury as continuous variables throughout treatm ent between DC 1 to DC F, a borde rline significant correlation of 0.23 (P = 0.0549) was found in the control group, but not detected in the headgear or bionator groups (correlations -0.1 1, -0.06, respectively).

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16 Table 3-1. Subject charact eristics by treatment group. Characteristic B (n=87) C (n=81) HG/BP (n=93) P-value Sex (% female) 40% 38% 38% 0.93 Race (% white) 87% 93% 95% 0.20 Age at baseline: mean (s.d.) 9.6 (1.1) 9.5 (0.8) 9.7 (0.8) 0.74 Initial molar class severity# % mild % moderate % high 26% 26% 47% 30% 26% 44% 31% 23% 46% 0.95 # definition of initial molar class severity: mild (bilateral 1/2 cusp), moderate (at least 1 side 3/4 cusp), or severe (at least 1 side full cusp). Table 3-2. Incidence of incisor injury (maxillary incisors). Treatment group (% new injury) Time point B HG/BP C P__ DC 1 DC 5 22.1 17.7 22.5 0.69 DC 5 DC 7 4.3 1.4 6.7 0.25 DC 7 DC F 3.2 2.9 10.9 0.13 DC 1 DC F 28.4 22.5 33.3 0.36

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17 0 5 10 15 20 25 30 3578910 Tooth #Number of Injurie s 3 2 1 Figure 3-1. Maxillary incisor in jury distribution and severity. Ellis Score

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18 0 1 2 3 4 5 6 7 823242526 Tooth# Number of Injuries 1 2 Figure 3-2. Mandibular incisor inju ry distribution and severity. Ellis Score

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19 0 5 10 15 20 25 30 35 40DC1 5DC1 7DC1 F% MALE FEMALE Figure 3-3. Incidence of injury in males vs. females throughout treatment. = P < 0.05. * *

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20 0 5 10 15 20 25 30 35 40 45 50CBHG/BP Treatment Grou p % MALE FEMALE Figure 3-4. Incidence of injury in sex betw een treatment groups from DC1-F (maxillary incisors). = P < 0.05. *

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21 CHAPTER 4 DISCUSSION In this study, we found 25% of the subjects had some level of incisor trauma at the baseline exam which falls in the range of previous ly reported prevalence of incisor injury of 6% to 34%.9-11 This shows that a significant number of patients already had some form of dental trauma during early childhood. In a study of Brazili an preschool children from birth to 6 years old, 35.5% of the children already had signs of dental trauma.28 Therefore, if orthodontic early treatment is to have any effect on the incide nce of this early inci sor trauma, orthodontic treatment would most likely need to be ini tiated soon after the erupt ion of the permanent incisors. Thus, determination of the initial onset of trauma w ould be pertinent to prevention. The prevalence of incisor injury at baseline was not statistically different between boys and girls at the mixed dentition stage. This is similar to the results found by Koroluk et al.26 Marcenes et al.29 also found no difference in prevalence betw een boys and girls at 9 years of age living in Syria. However, we observed that male s had a higher incidence of trauma during the phase-2 treatment period. This finding is consistent with several investigators.12,14,15 This could be due to increased activity of boys at this age. Throughout the trial, the incide nce of incisor trau ma was not statistically significant between the 3 treatment groups. All three gr oups showed a trend of decreased incidence between phase 1 and phase 2. Bauss et al.12 and Caliskan et al.13 both found that children aged 8 -11 years, an age range where phase I treatment usually occurs, exhibited the highest prevalence of dental trauma. Children at these ages ma y exhibit increased risk -taking behaviors and physical leisure activities such as school sports30, therefore increasing the risk of injury during treatment. Nonetheless, the decrease in inci dence between phase 1 and phase 2 may implicate the potential benefit of early treatment in order to reduce risks of trauma later on.

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22 During early childhood, seve ral nondental factors may also play a role in affecting dental trauma and should be considered. Socio-economic influences can also have a significant effect on a childs experience w ith dental injuries.17 Nicolau et al.16 found that adolescents who experienced adverse psychosocial environments such as non-nuclear families, paternal punishments, and poor school performance along th e life course had more traumatic dental injuries than their counterparts who expe rienced more favorable environments. Mercenes et al.14 discovered a higher inciden ce of incisor injury in children from mothers with higher educational background. Odoi et al.31 associated behavioral problems such as peer relationship problems, hyperactiv ity/inattention, and emotional distress with occurrence of traumatic dental injury. Perheentupa et al.32 attributed increased toot h trauma to high alcohol consumption and overweight. We observed that approximately 78% percent of total incisor injury occurred in the maxillary incisors while 22% occurred in the mandi bular incisors. Most of the injuries involved the maxillary central incisors followed by maxillary lateral incisors. This is in agreement with previous studies.12,13,33 It is very likely that the susceptibil ity of teeth to trauma is related to their position in the dental arch. Maxi llary incisors are usually the mo st anteriorly positioned teeth, therefore it is conceivable th at they will have the highest frequency of trauma. Some studies found enamel-dentin fractures w ithout pulpal involvement to be the most common form of injury. 4,13 Other investigations, in contrast report enamel fr acture or luxation to be the most common fracture type. 1,5,6 Our investigation revealed the majority of trauma consisted of enamel fractures. Only 19% of the injuries involved dentin, and only 1 subject had trauma with pulpal exposure. Fo rtunately, this shows th at the majority of trauma is minor and could be fixed with composite rest orations with good long term prognosis.34 Therefore, the cost

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23 of treating an injured tooth with restorations versus cost of orthodontic prevention must be considered in order to determin e the optimal cost/benefit ratio. The reports on whether increased overjet may play a significant pr edisposing factor for incisal trauma are conflicting. Bauss et al.12 found higher prevalence of trauma in subjects with overjet values greater than 3mm. Jarvinen24 attributed increased trauma to overjet values 6mm or greater. However, some studies found that in creased overjet may not be positively correlated with the risk of dental injury.22,35 Koroluk et al.26 found no differences between mean overjet of patients with and without incisor trauma at baseline. In this study, we found no correlation between initial overjet and preval ence of trauma. In addition, we found no correlation between changes in overjet with incidence of trauma throughout treatment. The conflicting results reported by the literature may be due to several factors such as trauma classification, dentition studied, geographical and behavi oral differences between st udy locations and countries. Nonetheless, it seems logical that patients with se vere overjet may be at greater risk of injury simply because the incisor protrusion.

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24 CHAPTER 5 CONCLUSIONS In conclusion, we have found that a significant number of patients already had some level of incisor injury prior to any treatment. No correlations were found between ini tial overjet values and prevalence of trauma. Early orthodontic treatment did not seem to have a significant effect on the incidence of trauma. The majority of the injuries that occurred prior to and during treatment were minor and consisted of enamel fract ures. Most of the inju ries occurred in the maxillary central incisors and in general, males showed higher risk of trauma than females.

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25 LIST OF REFERENCES 1. Andreasen JO. Etiology and pathogenesis of tr aumatic dental injuries A clinical study of 1298 cases. Scand J Dent Res 1970;78:329-42. 2. Andreasen JO, Ravn JJ. Epidemiology of traumatic dental injuries to primary and permanent teeth in a Danish population sample. Int J Oral Surg 1972;1:235-9. 3. Ravn JJ. Dental injuries in Copenha gen schoolchildren, sc hool years 1967-1972. Comm Dent Oral Epidemiol 1974;2:231-45. 4. Zerman N, Cavalleri G. Traumatic injuries to permanent incisors. Endod Dent Traumatol 1990;9:61-4. 5. Petti S, Tarsitani G. Traumatic injuries to anterior teeth in Italian schoolchildren: prevalence and risk factors. Endod Dent Traumatol 1996;12:294-7. 6. Zaragoza AA, Catala M, Colmena ML, Valdem oro C. Dental trauma in schoolchildren six to twelve years of age. AS DC J Dent Child 1998;65:492-4. 7. Marcenes W, Alessi ON, Traebert J. Causes and prevalence of traumatic injuries to the permanent incisors of school children aged 12 years in Jaragua do Sul, Brazil. Int Dent J 2000;50:87-92. 8. Alonge OK, Narendran S, Williamson DD. Prevalence of fractured incisal teeth among children in Harris County, Texas. Dent Traumatol 2001;5:218-221. 9. Hamilton FA, Hill FJ, Holloway PJ. An inve stigation of dentoalveolar trauma and its treatment in an adolescent popul ation. Part 1: The prevalence and incidence of injuries and the extent and adequacy of treatment received. Br Dent J 1997;182:91-95. 10. Burton J, Pryke L, Rob M, Lawson JS. Tr aumatized anterior teeth amongst high school students in northern Sydney. Aust Dent J 1985;30:346-348. 11. Kaba AS, Marechaux SC. A fourteen-year follow-up study of traumatic injuries to the permanent dentition. J Dent Child 1989;56:417-425. 12. Bauss O, Rohling J, Schwestka-Plly R. Pr evalence of traumatic injuries to the permanent incisors in candidates for orthodontic treatment. Dent Traumat 2004;20:61-66. 13. Caliskan MK, Turkun M. Clinical investig ations of traumatic injuries of permanent incisors in Izmir, Turkey. Endod Dent Traumatol 1995;11:210-3. 14. Dearing SG. Overbite, overjet, lip-drap e and incisor tooth fracture in children. NZ Dent J 1984;80:50-2. 15. Kania MJ, Keeling SD, McGorray SP, Wheeler TT, King GJ. Risk factors associated with incisor injury in elementa ry school children. Angle Orthod 1996;66:423-32.

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26 16. Nicolau B, Marcenes W, Sheiham A. The relationship between trau matic dental injuries and adolescents development along the life course. Comm Dent Oral Epidemiol 2003; 31:306-13. 17. Marcenes W, Zabot NE, Traebert J. Socioeconomic correlates of traumatic injuries to the permanent incisors in schoolchildren aged 12 years in Blumenau, Brazil. Dent Traumatol 2001;17:222-6. 18. Eichenbaum I. A correlation of trauma tized anterior teeth occlusion. J Dent Child 1963; 30:229-236. 19. OMullane D. Some factors predisposing to injuries of permanent incisors in school children. Br Dent J 1973;134:328-332. 20. McEwen J, McHugh W. Fractured maxillary central incisors and incisal relationship. J Dent Res 1967;46:1290. 21. Otuyemi OD. Traumatic anterior dental injuries related to in cisor overjet and lip competence in 12-year-old Nigeri an children. Int J Paediatr Dent 1994;4:81-5. 22. Brin I, Ben-Bassat Y, Heling I, Brezniak N. Profile of an orthodontic patient at risk of dental trauma. Endod Dent Traumatol 2000;16:111-5. 23. Nguyen QV, Bezemer PD, Habets L, PrahlAndersen B. A systemtic review of the relationship between overjet size and tr aumatic dental injuries. Eur J Orthod 1999;21: 503-515. 24. Jarvinen S. Incisal overjet and trauma tic injuries to upper permanent incisors. A retrospective study. Acta Odontol Scand 1978;36:359-62. 25. Burden DJ. An investigation of the asso ciation between overjet size, lip coverage, and traumatic injury to maxillary incisors. Eur J Orthod 1995;17:513-7. 26. Koroluk LD, Tulloch JFC, Phillips C. Inci sor trauma and early treatment for Class II Division 1 malocclusion. Am J Orthod Dentofacial Orthop 2003;123:117-26. 27. Wheeler TT, McGorray SP, Dolce C, Tayl or MG, King GJ. Effectiveness of early treatment of Class II malocclusi on. Am J Orthod Dentofacial Orthop 2002;121:9-17. 28. Kramer PF, Zembruski C, Ferreira SH, Fe ldens CA. Traumatic dental injuries in Brazilian preschool childre n. Dent Traumatol 2003;19:299-303. 29. Marcenes W, Beiruti N, Tayfour D, Issa S. Epidemiology of traumatic injuries to the permanent incisors of 9-12-year-old school children in Damascus, Syria. Endod Dent Traumatol 1999;15:117-23.

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27 30. Traebert J, Bittencourt DD, Peres KG, Peres MA, de Lacerda JT, Marcenes W. Aetiology and rates of treatment of traumatic dental injuries among 12-year-old school children in a town in southern Brazil. Dent Traumatol 2006;22:173-8. 31. Odoi R, Croucher R, Wong F, Marcenes W. The relationship between problem behavior and traumatic dental injury amongst children aged 7-15 years old. Co mmunity Dent Oral Epidemiol 2002;30:392-6. 32. Perheentupa U, Laukkanen P, Veijola J, Jouka maa M, Jarvelin MR, Laitinen J, Oikarinen K. Increased lifetime prevalence of dental trauma associated with previous non-dental injuries, mental distress and high alcohol consumption. Dent Traumatol 2001;17:10-16. 33. Oikarinen K, Kassila O. Ca uses and types of traumatic to oth injuries treated in a public dental health clinic. Endod Dent Traumatol 1987;3:172-7. 34. Zadik D, Chosack A, Eidelman E. The prognosis of traumatized permanent anterior teeth with fractures of the enamel and den tin. Oral Surg Oral Med Oral Path 1979;47: 173-5. 35. Stokes AN, Loh T, Teo CS, Bagramian RA Relation between incisal overjet and traumatic injury: a case control study. Endod Dent Traumatol 1995;11:2-5.

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28 BIOGRAPHICAL SKETCH David Ruey Chen was born in Taichung, Taiwan in 1978. He received his BS in biological sciences from the University of Ca lifornia Davis in 2000. He graduated from the University of California San Francisco in 2004 ob taining a Doctor of Dental Science degree and was inducted into the Omicron Kappa Upsilon Nati onal Dental Honor Society. He continued his dental education at the University of Florida and received a degree of Master of Science with a certificate in orthodontics in 2007.


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Title: Effect of Early Class II Treatment on the Incidence of Incisor Trauma
Physical Description: Mixed Material
Copyright Date: 2008

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Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
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EFFECT OF EARLY CLASS II TREATMENT ON THE INCIDENCE OF INCISOR
TRAUMA




















By

DAVID RUEY CHEN


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA

2007
































O 2007 David Ruey Chen










ACKNOWLEDGMENTS

I thank the members of my supervisory committee, for their mentoring; my family and

friends, for their continual support and encouragement.














TABLE OF CONTENTS


page


ACKNOWLEDGMENTS .............. ...............3.....


LIST OF TABLES .........__... ......._. ...............5....


LIST OF FIGURES .............. ...............6.....


AB S TRAC T ......_ ................. ............_........7


CHAPTER


1 INTRODUCTION ................. ...............9.......... ......


2 MATERIALS AND METHODS ................. ...............11.......... ....


Subj ects ................. ...............11.................
Inclusion Criteria ................. ...............11.......... .....
M ethods ................. ...............11.......... .....

Data Analysis............... ...............12


3 RE SULT S ................. ...............14.......... .....


4 DI SCUS SSION ................. ...............2.. 1......... ....


5 CONCLUSIONS .............. ...............24....


LIST OF REFERENCES ................. ...............25................


BIOGRAPHICAL SKETCH .............. ...............28....











LIST OF TABLES

Table page

3-1 Subj ect characteristics by treatment group. ..........__......__ ....___ ..........1

3-2 Incidence of incisor injury maxillaryy incisors) ................. .......___ ...... .........16












LIST OF FIGURES

Figure page

2-1 Modified Ellis Classification. ............. ...............13.....

3-1 Maxillary incisor injury distribution and severity. ............. ...............17.....

3-2 Mandibular inci sor inj ury di stribution and severity ................. ...............18.............

3-3 Incidence of injury in males vs. females throughout treatment. = P < 0.05. ........._........19

3-4 Incidence of injury in sex between treatment groups from DC1-F maxillaryy
incisors). = P < 0.05. ............. ...............20.....









Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

EFFECT OF EARLY CLASS II TREATMENT ON THE INCIDENCE OF INCISOR
TRAUMA

By

David Ruey Chen

May 2007

Chair: Calogero Dolce
Major: Dental Sciences

Many studies have demonstrated the frequency of dental injuries in children and

adolescents. The purpose of this study was to evaluate the prevalence and the effect on

incidence of incisor trauma in patients that participated in a clinical trial designed to investigate

early growth modifications in the treatment of CLII malocclusion. The subjects were categorized

into 3 groups based on the type of treatment during phase-1: (1) headgear/biteplane, (2) bionator,

(3) no treatment observation group. All 3 groups underwent phase-2 treatment with fixed

appliances. Incisor injury was scored at every data collection point with the Ellis index by a

single-blinded examiner using dental casts, intraoral photos, panoramic and periapical x-rays.

Twenty-five percent of the subj ects had some level of incisor trauma at baseline exam. No

significant differences were found in regards to sex and prevalence of injury at baseline, but

males did show higher incidence of injury throughout the course of treatment. No differences in

incidence of trauma were found between the 3 groups throughout treatment. The maj ority of the

injuries were minor and consisted of enamel fractures only (80%). Seventy-eight percent of the

injuries occurred in the maxillary incisors with central incisors being the most common. Early

orthodontic treatment does not seem to affect the incidence of incisor injury. The maj ority of the










injuries prior to and during treatment were minor, therefore the cost benefit ratio of orthodontic

treatment in order to prevent incisor trauma is doubtful.









CHAPTER 1
INTTRODUCTION

Dental injuries are common and present an important dental public health problem.

Many epidemiological studies during the last three decades have shown the frequency of dental

injuries in children and adolescents. -" The occurrence of dental injuries in a population can be

defined by its prevalence and incidence. The prevalence of incisor injury has been reported to

range from 6% to 34%.9-11 Falls, collisions, sporting activities, and traffic accidents have been

reported to be the main cause of most dental injuries.12,13 Variables such as age, gender, socio-

economic status, and behavioral problems may also influence the frequency of dental trauma.

Bauss et al.12 and Caliskan et al.13 both found that patients aged 8-11 years exhibited the

highest prevalence of dental trauma. It has been shown that incisor injuries occur more

frequently in males.14,15 Socio-economic influences can also have a significant effect on a

child's experience with dental injuries.16,17 Studies have shown a positive correlation between

the frequency of incisor trauma with increased protrusion,18,19 Class II malocclusion,3,20

increased overjet,21-24 and lip incompetence.19,25 Early orthodontic treatment for children with

such characteristics has been recommended in order to prevent incisor trauma and its

sequelae.22,25 Nguyen et al.23 had suggested the incorporation of overj et as a malocclusion item

into orthodontic treatment indices because of its potential correlation with dental trauma.

Although the indications for early orthodontic treatment in order to diminish the

likelihood of trauma to permanent incisors have been presented by several authors,

Koroluk et al.26 found the maj ority of injuries to be minor and easily treated at low cost and with

good long-term prognosis. They concluded that early growth modification might have some

effect on the incidence of trauma but the expected cost of trauma per child to be less for those

who had a 2-phase orthodontic treatment.










The efficacy of early intervention is largely dependent on the timing of treatment and

peak occurrence of injury. Orthodontic intervention could be ineffective with minimal benefits if

dental trauma occurs before the start of treatment. Currently, few reports are available regarding

the effectiveness of early orthodontic treatment in order to reduce the incidence of incisor

trauma.

The purpose of this study was to evaluate the prevalence and the effect on incidence of

incisor trauma in patients that participated in a clinical trial designed to investigate early growth

modifications in the treatment of CLII malocclusion.









CHAPTER 2
MATERIALS AND METHODS

Subj ects

The subj ects were part of a previous prospective, longitudinal, randomized clinical trial

designed to examine and report the effectiveness of early treatment with headgear/biteplane

(HG/BP) or with bionator (B) in patients with Class II malocclusion and compare results with

changes over a similar time period in an observation (C) group. A stratified block randomization

procedure was used to assign a treatment protocol (HG/BP, B, C) during Phase-1 for each

patient. Strata were defined by severity of Class II malocclusion, need for preparatory treatment,

mandibular plane angle, race, and gender. After completing Phase-1, all groups underwent fixed

appliances in Phase-2, followed by a retention/follow-up period. The study design and subject

selection are described in detail in the previous publication.27

Inclusion Criteria

The inclusion criteria included: bilateral greater than or equal to one-half-cusp Class II

molars, or unilateral greater than one-half-cusp Class II molars, fully erupted permanent first

molars, not more than 3 permanent canines or premolars, positive overj et and overbite, and good

general and dental health.

Methods

Incisor injury was assessed at all data collection (DC) points using the Modified Ellis

Classification (Figure 2-1). Maxillary (#7-10) and mandibular (#23-26) incisors were scored.

Study models, intraoral/extraoral photos, x-rays (lateral cephlogram, panoramic, and periapicals

taken during Phase-2) obtained at each DC point was used to inspect incisor injury. Any existing

or new restorations on each tooth were noted. One trained and reliability tested examiner [DRC]









recorded all injuries. The records for all DC points of each patient were evaluated at the same

time in order to eliminate the chance of recording errors over time.

Overj et was assessed for each patient at all DC points using the lateral cephalograms

taken at each data collection period.

Data Analysis

Statistical comparisons were performed at baseline (DC 1), end of Phase 1 (DC 5),

baseline at Phase 2 (DC 7), and end of Phase 2 (DC F). Relationships between outcomes and

covariates were examined with chi-square and Fisher exact tests. For all analyses, a p-value less

than 0.05 was considered statistically significant. Pearson's correlation coefficient was used to

examine any relationship between initial overj et and trauma.














Score Injury Description

0 Non injured tooth

1 Fracture of the crown involving enamel only

2 Fracture of the crown involving enamel and dentin

3 Fracture of crown involving pulp (untreated, pulp cap,

pulpotomy, root filling)

4 Nonvital without crown fracture

5 Root fracture

6 Lost due to trauma

7 Missing tooth





Figure 2-1. Modified Ellis Classification.









CHAPTER 3
RESULTS

Table 3-1 presents the subject characteristics by treatment group. At DC 1, 64 of the 261

participants (25%) had some level of incisor trauma (B=27 (31%), HG/BP=18 (19%) C=19

(23%)). The differences in the distribution of subj ects with trauma to each treatment group were

not statistically significant (P = 0.18). Figures 3-1 and 3-2 shows the distribution and severity of

injury to maxillary and mandibular teeth. The majority (80%) of the injuries were scored as a

minor fractures involving enamel only. Fractures involving enamel and dentin consisted of 19%

and only 1 subject had trauma with pulpal exposure. The maxillary incisors had the highest

number of injuries (77%), with central incisors being the most common. The prevalence of

incisor trauma at DC 1 were not statistically significant between males and females (P = 0.27),

with 21% of females and 27% of males having some degree of incisor trauma.

Since the maj ority of the injuries occurred in the maxilla, further analysis focused on the

incidence of only maxillary incisor injury. As shown in Table 3-2, there were no differences in

the incidence of new trauma between treatment groups during phase-1 (DC 1-5), between

treatment phases (DC5-7), during phase-2 (DC7-F), and overall (DC1--F). As seen in Figure

3-3, there was a statistically significant higher incidence of trauma in males compared with

females during the entire study. During the entire course of the study, only the control group and

not the HG/BP or bionator groups showed a statistically significant higher incidence of trauma in

males than females (Figure 3-4).

Overj et was measured to determine if overj et correlated with trauma in males. The mean

overj et value at baseline was 5.81Imm (A 2.77 SD; range, 0.87-13.2) for males and 5.48mm (A

2.30 SD; range, 0.5 1-1 1.2) for females. No correlation was found between initial overj et value

and amount of upper incisor trauma at baseline (Pearson Correlation Coefficient = 0.02; P =










0.75). When evaluating baseline overjet and change in upper incisor injury as continuous

variables throughout treatment between DC 1 to DC F, a borderline significant correlation of

0.23 (P = 0.0549) was found in the control group, but not detected in the headgear or bionator

groups (correlations -0. 11, -0.06, respectively).













Table 3-1. Subject characteristics by treatment group.
B C HG/BP
Characteristic (n= 87) (n= 81) (n= 93) P-value
Sex (% female) 40% 38% 38% 0.93
Race (% white) 87% 93% 95% 0.20
Age at baseline: mean (s.d.) 96(.) 9.5 (0.8) 9.7 (0.8) 0.74
Initial molar class severity#
% mild 26% 30% 31%
% moderate 26% 26% 23% 0.95
% high 47% 44% 46%
# definition of initial molar class severity: mild (bilateral 1/2 cusp), moderate (at least 1 side 3/4 cusp), or
severe (at least 1 side full cusp).


Table 3-2. Incidence of incisor injury maxillaryy incisors).
Treatment group
(% new injury)
Time point B HG/BP C P
DC 1 DC 5 22.1 17.7 22.5 0.69


DC 5 DC 7
DC 7 DC F
DC 1 -DC F


6.7
10.9
33.3


0.25
0.13
0.36


4.3
3.2
28.4


1.4
2.9
22.5










35


30


25


S20 -1IEllis Score


O 15 0 3


121






7 8 9 10

Tooth #


Figure 3-1. Maxillary incisor injury distribution and severity.

















6


3-( 5 Ellis Score





E3

2







23 24 25 26

Tooth #

Figure 3-2. Mandibular incisor injury distribution and severity.
































18















35


30 -


25


4 20 i


15


10 -


5


MALE
FEMALE


O


DC1-5


DC1-7


DC1-F


Figure 3-3. Incidence of injury in males vs. females throughout treatment. = P < 0.05.



















MALE
FEMALE









C B HGIBP
Treatment Grouo,

Figure 3-4. Incidence of injury in sex between treatment groups from DC1-F maxillaryy
incisors). = P < 0.05.









CHAPTER 4
DISCUSSION

In this study, we found 25% of the subj ects had some level of incisor trauma at the

baseline exam which falls in the range of previously reported prevalence of incisor injury of 6%

to 34%.9-11 This shows that a significant number of patients already had some form of dental

trauma during early childhood. In a study of Brazilian preschool children from birth to 6 years

old, 35.5% of the children already had signs of dental trauma.28 Therefore, if orthodontic early

treatment is to have any effect on the incidence of this early incisor trauma, orthodontic

treatment would most likely need to be initiated soon after the eruption of the permanent

incisors. Thus, determination of the initial onset of trauma would be pertinent to prevention.

The prevalence of incisor injury at baseline was not statistically different between boys

and girls at the mixed dentition stage. This is similar to the results found by Koroluk et al.26

Marcenes et al.29 also found no difference in prevalence between boys and girls at 9 years of age

living in Syria. However, we observed that males had a higher incidence of trauma during the

phase-2 treatment period. This finding is consistent with several investigators. 12,14,15 This could

be due to increased activity of boys at this age.

Throughout the trial, the incidence of incisor trauma was not statistically significant

between the 3 treatment groups. All three groups showed a trend of decreased incidence

between phase 1 and phase 2. Bauss et al.12 and Caliskan et al.13 both found that children aged 8

-11 years, an age range where phase I treatment usually occurs, exhibited the highest prevalence

of dental trauma. Children at these ages may exhibit increased risk-taking behaviors and

physical leisure activities such as school sports30, therefore increasing the risk of injury during

treatment. Nonetheless, the decrease in incidence between phase 1 and phase 2 may implicate

the potential benefit of early treatment in order to reduce risks of trauma later on.









During early childhood, several nondental factors may also play a role in affecting dental

trauma and should be considered. Socio-economic influences can also have a significant effect

on a child's experience with dental injuries." Nicolau et al.16 found that adolescents who

experienced adverse psychosocial environments, such as non-nuclear families, paternal

punishments, and poor school performance along the life course had more traumatic dental

injuries than their counterparts who experienced more favorable environments.

Mercenes et al.14 discovered a higher incidence of incisor injury in children from mothers with

higher educational background. Odoi et al.31 associated behavioral problems such as peer

rel ati onship problems, hyperactivity/inattenti on, and emoti onal di stores s with occurrence of

traumatic dental injury. Perheentupa et al.32 attributed increased tooth trauma to high alcohol

consumption and overweight.

We observed that approximately 78% percent of total incisor injury occurred in the

maxillary incisors while 22% occurred in the mandibular incisors. Most of the injuries involved

the maxillary central incisors followed by maxillary lateral incisors. This is in agreement with

previous studies.12,13,33 It is very likely that the susceptibility of teeth to trauma is related to their

position in the dental arch. Maxillary incisors are usually the most anteriorly positioned teeth,

therefore it is conceivable that they will have the highest frequency of trauma.

Some studies found enamel-dentin fractures without pulpal involvement to be the most

common form of injury. 4,13 Other investigations, in contrast, report enamel fracture or luxation

to be the most common fracture type. 1,5,6 Our investigation revealed the maj ority of trauma

consisted of enamel fractures. Only 19% of the injuries involved dentin, and only 1 subject had

trauma with pulpal exposure. Fortunately, this shows that the maj ority of trauma is minor and

could be fixed with composite restorations with good long term prognosis.34 Therefore, the cost









of treating an injured tooth with restorations versus cost of orthodontic prevention must be

considered in order to determine the optimal cost/benefit ratio.

The reports on whether increased overj et may play a significant predisposing factor for

incisal trauma are conflicting. Bauss et al.12 found higher prevalence of trauma in subj ects with

overj et values greater than 3mm. Jarvinen24 attributed increased trauma to overj et values 6mm or

greater. However, some studies found that increased overjet may not be positively correlated

with the risk of dental injury.22,35 Koroluk et al.26 found no differences between mean overj et of

patients with and without incisor trauma at baseline. In this study, we found no correlation

between initial overj et and prevalence of trauma. In addition, we found no correlation between

changes in overj et with incidence of trauma throughout treatment. The conflicting results

reported by the literature may be due to several factors such as trauma classification, dentition

studied, geographical and behavioral differences between study locations and countries.

Nonetheless, it seems logical that patients with severe overj et may be at greater risk of injury

simply because the incisor protrusion.









CHAPTER 5
CONCLUSIONS

In conclusion, we have found that a significant number of patients already had some level

of incisor injury prior to any treatment. No correlations were found between initial overj et

values and prevalence of trauma. Early orthodontic treatment did not seem to have a significant

effect on the incidence of trauma. The maj ority of the injuries that occurred prior to and during

treatment were minor and consisted of enamel fractures. Most of the injuries occurred in the

maxillary central incisors and in general, males showed higher risk of trauma than females.









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BIOGRAPHICAL SKETCH

David Ruey Chen was born in Taichung, Taiwan in 1978. He received his BS in

biological sciences from the University of California Davis in 2000. He graduated from the

University of California San Francisco in 2004 obtaining a Doctor of Dental Science degree and

was inducted into the Omicron Kappa Upsilon National Dental Honor Society. He continued his

dental education at the University of Florida and received a degree of Master of Science with a

certificate in orthodontics in 2007.