Timothy T. Wheeler

Anteroposterior skeletal and dental changes after early Class II treatment with bionators and headgear.

In this study we examined anteroposterior cephalometric changes in children enrolled in a randomized controlled trial of early treatment for Class II malocclusion. Children, aged 9.6 +/- 0.8 years at the start of study, were randomly assigned to control (n = 81), bionator (n = 78), and headgear/biteplane (n = 90) treatments. Cephalograms were obtained initially, after Class I molars were obtained or 2 years had elapsed, after an additional 6 months during which treated subjects were randomized to retention or no retention and after a final 6 months without appliances. Calibrated examiners, blinded to group, used Johnstons analysis to measure anteroposterior cephalometric changes. Statistical analysis was used to determine annual skeletal and dental changes during treatment, retention, and follow-up, and overall. Our data reveal that both bionator and head-gear treatments corrected Class II molar relationships, reduced overjets and apical base discrepancies, and caused posterior maxillary tooth movement. The skeletal changes, largely attributable to enhanced mandibular growth in both headgear and bionator subjects, were stable a year after the end of treatment, but dental movements relapsed.

Comparison of peer assessment ratings (PAR) from 1-phase and 2-phase treatment protocols for class II malocclusions

The purpose of this study was to compare the dentoalveolar outcomes after 1-phase and 2-phase orthodontic treatment of Class II malocclusions. Class II subjects (n = 208) were randomized to 1-phase or 2-phase treatment with either bionator or headgear/biteplate. The peer assessment rating (PAR) was calculated from pretreatment, prephase 2, and final study models. Chi-square, Kruskal-Wallis, and Wilcoxon rank sum tests were used to evaluate the differences among treatment groups, sexes, races, pretreatment, mandibular plane angle, severity, and compliance. Spearman rank correlation coefficients were used to examine relationships between PAR at different times. The dropout rate of 24.6% did not adversely affect the ability to detect differences of clinical importance or impact treatment groups disproportionately. There were no significant differences with respect to initial PAR or final PAR among the 3 treatment protocols. The 2 early treatment groups had lower PAR scores than the 1-phase group before phase 2 (P =.0001). Lower PAR scores were achieved at both the beginning and end of phase 2 in girls (P =.03; P =.02, respectively). There were differences in the pre-phase-2 and post-phase-2 PAR scores based on initial severity (P =.0006; P =.02, respectively), with greater improvement in the patients whose malocclusions were less severe initially. Mandibular plane angle had no effect on pre-phase-2 or post-phase-2 PAR scores. These results do not support the hypothesis that different dentoalveolar outcomes are obtained between 2-phase and 1-phase treatment of Class II malocclusions.

Risk factors associated with temporomandibular joint sounds in children 6 to 12 years of age.

The relationship between temporomandibular joint (TMJ) sounds and a persons dental and skeletal characteristics is poorly understood. In this study, data were obtained from 3428 grade schoolchildren (mean age = 9.0 years, SD = 0.8, range 6 to 12 years), without a history of orthodontic treatment. Each child had been examined independently by one of six orthodontists to assess: TMJ sounds (none, click, crepitus), gender, age, race (white/black), skeletal relationships (convexity, maxillary, and mandibular positions), malocclusion (molar class, overjet, overbite, anterior crowding, posterior crossbite), maximum opening, chin trauma (none, cut, scar), and history of lower facial trauma. Temporomandibular joint sounds were present in 344 children (10.0% of the sample); 276 (8.1%) had an isolated unilateral sound, 254 (7.4%) had unilateral clicking, 50 (1.5%) had bilateral clicking, 22 (0.6%) had unilateral crepitus, and 11 (0.3%) had bilateral crepitus. Univariate analyses compared children with and without sounds for each variable; logistic regression analyses examined the relationship between groups of variables and TMJ sounds. The prevalence of TMJ sounds was associated with examiner (chi 2 = 23.4, df = 5, p < 0.001); increased prevalence of TMJ sounds occurred in children with maxillary anterior crowding (t = 2.8, p < 0.006), mandibular anterior crowding (t = 3.0, p < 0.002), and increased maximum opening (t = 4.7, p < 0.001). In contrast to other reports on children, the prevalence of joint sounds was not associated with age, race, gender, or molar class.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors associated with incisor injury in elementary school children

This study examined risk factors associated with incisor injury in 3396 third and fourth grade school children in Alachua County, Florida. One of six orthodontists completed a standardized examination form for each child to assess severity of incisor injury, gender, age, race, skeletal relationships, morphologic malocclusion, incisor exposure, interlabial gap, TMJ sounds, chin trauma, and history of lower facial trauma. One in five (19.2%) exhibited some degree of incisor injury. This was limited to a single tooth in 73.1% of those with injury, while enamel injury predominated (89.4%). The majority of the injuries (75.4%) were localized in the maxillary arch, with central incisors the most frequently traumatized. Chi-square tests of association indicated that gender, race, school, orthodontist, history of lower facial trauma, chin trauma, profile, and maxillary and mandibular horizontal positions were associated with incisor injury (P < 0.05). Wilcoxon rank sum tests identified differences in age, overjet, time of screening, and interlabial gap between those with and without injury (P < 0.05). Results of logistic regression analyses indicated risk of incisor injury was greater for children who had a prognathic maxilla, a history of trauma, were older, were male, and had greater overjet and mandibular anterior spacing.

Occlusal traits and perception of orthodontic need in eighth grade students

In 1994, 1155 eight-grade students in Alachua County, Fla., were asked about self-perception of and level of concern for their occlusal status. Clinical assessments of orthodontic parameters were also recorded. Twenty-five percent of the students had a history of orthodontic treatment. Of the remaining students who had no history of orthodontic treatment, 74% reported satisfaction with the way their teeth looked, 64% expressed no perceived need for braces, and 57% were judged clinically to have optional or no orthodontic needs. Sex, soft tissue profile, overjet, anterior crowding, and molar classification were significantly associated with the perception of need for braces while race and overbite were not. Clinical judgment of orthodontic need differed significantly among levels of satisfaction with teeth. Eighth graders with no history of orthodontic treatment were generally satisfied with the appearance of their teeth and perceived less need for braces than clinicians.

The timing of treatment for Class II malocclusions in children: a literature review

Two basic strategies for the timing of treatment for Class II malocclusions in children are common: (1) correction achieved in two phases, one during pre-adolescence (early treatment) and the other during the teen years; and (2) correction accomplished in one phase of active treatment during the adolescent years. The issues of efficacy and cost(risk)-benefit of these strategies have not been well delineated. Most clinical studies examining these issues have suffered serious methodological deficiencies, such as being retrospective, lacking adequate controls, and evaluating only successfully treated cases. However, despite a lack of objective data, clinicians have shown considerable interest in recent years in two-phase treatment. This paper reviews major issues of two-phase Class II treatment and concludes by delineating several important clinical questions which could be resolved by a carefully controlled prospective study.

Prevalence of Orthodontic Asymmetries

Epidemiological studies of the occlusal status of the US population do not include the prevalence of orthodontic asymmetries. To estimate the magnitude of dental and facial asymmetries in adolescents with no history of orthodontic treatment, data were analyzed from two mass orthodontic screenings that had been conducted on public schoolchildren in Florida. An analysis of orthodontic records of patients in treatment at the Virginia Commonwealth University graduate orthodontic clinic provided prevalence data on dental and facial asymmetries in a population of orthodontic patients. In the Florida studies, the two screenings yielded 5,817 untreated children (mean age, 9.3 +/- 0.8 years) and 861 untreated children (mean age, 14.4 +/- 0.5 years). Sagittal molar asymmetry was found in 30% of the children in the first screening and in 23% in the second screening. Additional asymmetry assessments in the second screening showed 12% facial asymmetry and 21% noncoincidence of dental midlines. Among orthodontic patients, the most common asymmetry trait was mandibular midline deviation from the facial midline. This occurred in 62% of patients, followed, in descending order of frequency, by lack of dental midline coincidence (46%), maxillary midline deviation from the facial midline (39%), molar classification asymmetry (22%), maxillary occlusal asymmetry (20%), mandibular occlusal asymmetry (18%), facial asymmetry (6%), chin deviation (4%), and nose deviation (3%).

Method to classify dental arch forms

INTRODUCTION The aim of this study was to propose a method to classify dental arch forms of subjects with normal occlusion into several types that can ensure both goodness of fit and clinical application. METHODS We selected 306 subjects with normal occlusion from 15,836 young adults, recorded 14 reference points that defined the distance between 2 arch forms as the area between 2 arches, and then classified the dental arch forms by using the partitioning around medoids clustering and silhouette method. We measured tooth size, arch width, basal arch width, arch depth, mesiodistal angulations, and buccolingual inclinations. RESULTS We identified 3 types of arch forms, and cross-classification of the maxillary by mandibular arch forms showed a more frequent distribution in the diagonal elements than in the off-diagonal elements. The 3 arch forms showed differences in tooth size, arch width, basal arch width, and inclination of the posterior teeth. CONCLUSIONS By defining area discrepancies as distance measures and applying them to the cluster method by using medoids, the dental arch form can be classified keeping control for the extremes without bias. It is hoped that this method will have possible clinical applications in determining the shape and number of preformed orthodontic arch forms.

Temporomandibular disorders after early class II treatment with bionators and headgears : results from a randomized controlled trial

Symptoms and signs of temporomandibular disorders were assessed in children enrolled in a randomized controlled trial of early treatment for Class II malocclusion. Children (mean age of 9.8 years) were assigned to a treatment protocol (bionator, n = 60; observation, n = 60; headgear/bite plane, n = 71) using randomized block stratification. Temporomandibular joint (TMJ) sounds, joint capsule pain to palpation, and muscle pain to palpation were scored as binary responses (present/absent in a subject). Determinations were made by blinded, calibrated examiners initially (DC1) and after a Class I molar correction was achieved or 2 years had elapsed (DC3). Univariate relationships among explanatory factors (group assignment, gender, age, time interval between DC1 and DC3, Class II severity, mandibular plane angle, preparatory treatment, whether Class I molar relation was achieved) and binary responses were explored using Chi square tables and ANOVA methods. Logistic regression modeled the relationship between binary responses and the explanatory variables. At DC1, the 3 groups were equivalent in the explanatory variables (P > .05). Subjects with a TMJ sound, joint pain, and/or muscle pain at follow-up were more likely those who had the sign at baseline (P < .01). Early treatment with bionators and headgear/bite planes did not place healthy children without these signs at risk for developing these signs. Only increasing age (for the development of sounds, P < .04) and failure to achieve a Class I molar relation (for development of muscle pain, P < .04) placed sign-free children at greater risk. Subjects with TMJ pain at baseline were 7 times more likely to have pain at follow-up if they had been treated with a headgear/bite plane or observed than if they had been treated with a bionator (P = .007). We conclude that an immediate benefit or risk for children receiving early Class II treatment with bionators and headgear/bite planes with respect to temporomandibular joint function does not exist with the prospect that Class II children with TMJ capsule pain may benefit from bionator therapy.

Orthodontists' Perceptions of the Impact of Phase 1 Treatment for Class II Malocclusion on Phase 2 Needs

The most appropriate timing for the treatment of Class II malocclusions is controversial. Some clinicians advocate starting a first phase in the mixed dentition, followed by a phase 2 in the permanent dentition. Others see no clear advantage to that approach and recommend that the entire treatment be done in the late mixed or early permanent dentition. This study examines how orthodontists, blinded to treatment approach, perceive the impact of phase 1 treatment on phase 2 needs. The sample consisted of 242 Class II subjects, aged 10 to 15, who had completed phase 1 or observation in a randomized clinical trial (RCT). For each subject, video orthodontic records, a questionnaire, a fact sheet, and a cephalometric tracing were sent to five randomly selected reviewing orthodontists blinded to subject group and study purpose. Reviewing orthodontists were asked to assess treatment need, general approach, need for extractions, priority, difficulty, and determinants. Orthodontists agreed highly on treatment need (95%) and moderately on treatment approach (84%) and extraction need (80%). They did not perceive differences in need, approach, or extractions between treated and control groups. Treated subjects were judged as less difficult (p = 0.0001) and to have a lower treatment priority (p = 0.0001) than controls. In ranking problems that affect treatment decisions, the orthodontists ranked dental Class II (p = 0.005) and skeletal relationships (p = 0.004) more highly in control than in treated patients. These data indicate that orthodontists do not perceive phase 1 treatment for Class II as preventing the need for a second phase or as offering any particular advantage with respect to preventing the need for extractions or other skeletal treatments in that second phase. They do view early Class II treatment as an effective means of reducing the difficulty of and priority for phase 2.