Cephalometric changes in growing patients with increased vertical dimension treated with cervical headgear.

PURPOSE: The aim of the present study was to investigate the cephalometric changes in patients with increased vertical dimension after treatment with cervical headgear compared to controls. METHODS: The sample of the present retrospective study consisted of 20 Class II patients (10 males, 10 females; mean age 8.54 ± 1.15 years) with increased vertical dimension treated with cervical headgear (treatment group) and 21 Class II patients (11 males, 10 females; mean age 8.41 ± 1.15 years) with increased vertical dimension who underwent no treatment (control group). Cephalograms were available for each subject at baseline (T1) and after treatment/observation time (T2) for both groups and cephalometric analysis allowed for evaluation of changes between time points and between groups. RESULTS: Regarding facial axis, N-ANS/ANS-Me, and overbite, there were no negatively significant changes in the treated group showing no significant worsening in the vertical dimension. Regarding facial angle, there was a significant increase in the treated group between the time points and when compared to the control group, showing counterclockwise rotation of the mandible in the treated group. CONCLUSIONS: The vertical dimension was not significantly altered after cervical headgear treatment although the anterior facial height was higher at the beginning of treatment. There was significant counterclockwise rotation of the mandible, and clockwise rotation and distal displacement of the maxilla after treatment.

Longitudinal growth changes in subjects with open-bite tendency: a retrospective study.

INTRODUCTION: This study was a cephalometric evaluation of the growth changes in untreated subjects with minimal overbite at 4 time points during 4 developmental stages from the early mixed dentition to the permanent dentition, as well as from the prepubertal phase to young adulthood. METHODS: A sample of 24 untreated subjects with minimal overbite (<1.5 mm) was selected retrospectively from the University of Michigan Growth Study and the Denver Child Growth Study. The sample was followed longitudinally from about 9 years of age through 17 years of age. Dentofacial changes at the 4 times (T1-T4), defined by the cervical vertebral maturation method, were analyzed on lateral cephalograms. Nonparametric statistical analysis was used for comparisons. RESULTS: Overbite on average increased by 2.3 mm during the overall observation period. Improvement occurred during the prepubertal interval (T1-T2; 2.4 mm), whereas no significant changes occurred in the pubertal and postpubertal stages. From prepubertal ages to young adulthood, the open-bite tendency improved in 91% of the subjects, with self-correction in 75%. Logistic regression analysis on the cephalometric variables at T1 with the value of overbite at T4 did not show a statistically significant correlation. CONCLUSIONS: Subjects with an open-bite tendency show improvement of their occlusal condition during the prepubertal stage, but there is no significant improvement after this. These results provide useful indications for appropriate orthodontic treatment timing for patients with an open-bite tendency.

Comparison of three methods to assess individual skeletal maturity.

BACKGROUND: The knowledge of facial growth and development is fundamental to determine the optimal timing for different treatment procedures in the growing patient. AIM: To analyze the reproducibility of three methods in assessing individual skeletal maturity, and to evaluate any degree of concordance among them. DESIGN: In all, 100 growing subjects were enrolled to test three methods: the hand-wrist, cervical vertebral maturation (CVM), and medial phalanges of the third finger method (MP3). Four operators determined the skeletal maturity of the subjects to evaluate the reproducibility of each method. After 30 days the operators repeated the analysis to assess the repeatability of each method. Finally, one operator examined all subjects' radiographs to detect any concordance among the three methods. RESULTS: The weighted kappa values for inter-operator variability were 0.94, 0.91, and 0.90, for the WRI, CVM, and MP3 methods, respectively. The weighted kappa values for intra-operator variability were 0.92, 0.91, and 0.92, for the WRI, CVM, and MP3 methods, respectively. CONCLUSION: The three methods revealed a high degree of repeatability and reproducibility. Complete agreement among the three methods was observed in 70% of the analyzed samples. The CVM method has the advantage of not necessitating an additional radiograph. The MP3 method is a simple and practical alternative as it requires only a standard dental x-ray device.

Management of impacted incisors following surgery to remove obstacles to eruption: a prospective clinical trial.

PURPOSE: The purpose of this study was to assess the effectiveness of rapid maxillary expansion (RME) vs simply monitoring the eruption of permanent maxillary incisors following the surgical removal of obstacles to their eruption (supernumerary teeth, odontomas). METHODS: Following surgical removal of the obstacles to incisor eruption (T1), 62 patients were randomly assigned to either the group to undergo RME (34 subjects; mean age 8 years, 11 months ± 11 months) or the group that was monitored without further treatment (28 subjects; mean age=9 years, 1 month ± 1 year). At T2 (1 year after T1), the prevalence rate of erupted incisors was recorded. Also, the time of eruption of the incisors and the amount of space loss were analyzed. RESULTS: At T2, eruption of impacted incisors occurred in approximately 82 percent of the RME group cases vs approximately 39 percent of the monitored group cases (chi-square=10.43, P<.001). Time of eruption was significantly faster in the RME group, and anterior space loss significantly smaller. CONCLUSIONS: Rapid maxillary expansion treatment following surgical removal of the obstacles to the eruption of permanent maxillary incisors appears to be an efficient interceptive approach leading to eruption of the incisors in four out of five cases within seven months.

Three-dimensional assessment of palatal change in a controlled study of unilateral posterior crossbite correction in the primary dentition.

The aim of this study was to quantify the palatal change in three groups of children: children with a unilateral posterior crossbite (TCB) who were treated, children with untreated unilateral posterior crossbite (UCB), and children without a crossbite (NCB). Study casts of 60 Caucasian children in the primary dentition (20 TCB, 20 UCB, and 20 NCB), aged 5.4 ± 0.7 years, were collected at baseline (T1) and at 1-year follow-up (T2). Both TCB and UCB groups had unilateral posterior crossbite and midline deviation. The TCB group was treated using a cemented acrylic splint expander in the upper arch. The study casts were scanned using a laser scanner and palatal surface area, palatal volume, and symmetry of the palatal vault were evaluated and compared between the three groups. At T1, the palatal volume of TCB (2698 mm(3)) and UCB (2585 mm(3)) was significantly smaller than that of NCB (3006 mm(3); P < 0.05, analysis of variance test). After treatment, the palatal volume of the TCB group (3087 mm(3)) increased and did not differ from the NCB group (3208 mm(3)), whereas the UCB (2644 mm(3)) had a significantly smaller palatal volume than the NCB or TCB groups (P < 0.05). The increase of palatal volume in the TCB group (389 mm(3)) was significantly greater than in the UCB (59 mm(3)) and NCB (202 mm(3)) groups. The symmetry of the palatal vault was greater than 90 per cent in all three groups at T1 and at T2. Treatment of unilateral posterior crossbite in the primary dentition has a significant effect, particularly on the palatal volume increase.

Treatment timing of MARA and fixed appliance therapy of Class II malocclusion.

The objective of this study is to evaluate the effect of timing on Mandibular Anterior Repositioning Appliance (MARA) and fixed appliance treatment of Class II malocclusion in a prospective clinical trial. The treated sample consisted of 51 consecutively treated patients at prepubertal (n = 21), pubertal (n = 15), and postpubertal (n = 15) stages of development. Control groups for the three treated groups were generated from growth data of untreated Class II subjects. Lateral cephalograms were digitized and superimposed via cephalometric software at T1 (pre-treatment) and T2 (after comprehensive treatment). The T1-T2 changes in the treated groups were compared to those in their corresponding control groups with Mann-Whitney tests with Bonferroni correction. Mandibular elongation was greater at the pubertal stage (Co-Gn +2.6 mm, with respect to controls). Headgear effect on the maxilla was greater in the pre-peak sample (Co-A -1.9 mm, with respect to controls). Dentoalveolar compensations (proclination of lower incisors, extrusion and mesialization of lower molars, and reduction in the overbite) were significant in the pre-peak and post-peak groups. Optimal timing for Class II treatment with MARA appliance is at the pubertal growth spurt, with enhanced mandibular skeletal changes and minimal dentoalveolar compensations.

Prevalence rate and dentoskeletal features associated with buccally displaced maxillary canines.

The aim of the study was to analyse the prevalence and distribution of buccally displaced canines (BDCs) in subjects scheduled for orthodontic treatment and to investigate the association between BDC and sagittal, vertical, and transverse dentoskeletal relationships. A study sample of 1852 subjects was examined, and it was divided randomly into two groups. A first group of 252 subjects served as control group: the 'reference' prevalence rates for the examined parameters were calculated in this group. The remaining 1600 subjects comprised the sample from which the experimental BDC group was derived. Presence of unilateral or bilateral maxillary BDC, ANB, and SN GOGn angles for sagittal and vertical skeletal relationships, intercanine and intermolar distances, and tooth crowding at the maxillary arch were recorded for each subject. The statistical significance of differences between the BDC and the control groups in transverse relations and tooth crowding at the upper arch was tested by means of independent sample t-tests. Chi-square tests were performed to compare the prevalence rates of BDC and also sagittal and vertical skeletal features in the two groups. The prevalence rate of BDC was 3.06 per cent with a male-to-female ratio of 1:1. BDC subjects exhibited a significant association with hyperdivergent skeletal relationships (38.8%), reduced maxillary intercanine width, and crowding in the upper arch. The presence of specific dentoskeletal characteristics can be considered as a risk indicator for developing a buccal displacement of upper permanent canines.

Effects of rapid maxillary expansion in hyperdivergent patients.

INTRODUCTION: This retrospective cohort study was performed to evaluate the skeletal and dental changes in the short and long terms in hyperdivergent patients treated with rapid maxillary expansion and fixed appliances. METHODS: The sample consisted of 143 patients who had rapid maxillary expansion with a Haas-type expander followed by edgewise therapy. Two groups were established: a normal vertical dimension group (mandibular plane angle >20° and <27°; n = 52) and a hyperdivergent group (mandibular plane angle ≥27°; n = 91). Lateral cephalograms were taken before treatment (average age, 11.5 years in both groups) and after fixed appliance therapy (average age, 14.3 years in both groups). Subjects who exhibited opening or closing in the mandibular plane angle during treatment greater than 1.5° (opening group, n = 23; closing group, n = 26) were followed in the long term (average age, 20.3 years). Longitudinal changes in the different groups were evaluated statistically as well as the prevalence rates of hyperdivergent patients in the opening and closing groups. RESULTS: No significant differences in treatment effects were found in any sagittal or vertical dentoskeletal variables examined. The long-term evaluation of the patients at 5 or more years posttreatment showed no significant skeletal changes. The prevalence rate of hyperdivergent patients in the opening group was not significant. CONCLUSIONS: The results of this study indicate that rapid maxillary expansion can be carried out successfully in patients with increased vertical dimensions without detrimental effects on the vertical skeletal relationships. Thus, an increased mandibular plane angle is not a contraindication for rapid maxillary expansion therapy.

Early vs late orthodontic treatment of deepbite: a prospective clinical trial in growing subjects.

INTRODUCTION: The aim of this prospective clinical trial was to compare the outcomes of prepubertal vs pubertal treatment of deepbite patients with a protocol including biteplane and fixed appliances. METHODS: A sample of 58 subjects with deepbite completed the study. A total of 34 subjects received treatment with removable biteplane appliances in the mixed dentition at a prepubertal stage of skeletal maturation (early treatment group), and 24 subjects were treated at a pubertal stage of skeletal maturation in the permanent dentition (late treatment group). All subjects of both groups were reevaluated after an average period of 15 months after the completion of fixed appliance therapy. Treatment outcomes were assessed statistically after a phase with removable biteplane appliances and at the posttreatment observation. RESULTS: Treatment duration was significantly shorter in the early treatment group than in the late treatment group. Overbite reduction was significantly greater in the late treatment group (-3.1 mm) than in the early treatment group (-1.4 mm). In the late treatment group, 92% of the patients had a corrected overbite 1 year after therapy. CONCLUSIONS: Treatment of deepbite at puberty in the permanent dentition leads to significantly more favorable outcomes than treatment before puberty in the mixed dentition.

A controlled study on diagnostic and prognostic measurements of palatally displaced canines on lateral cephalograms.

OBJECTIVES: The aim of this prospective controlled study was to determine the role that the lateral cephalogram can play in the detection of palatally displaced canines (PDCs). MATERIALS AND METHODS: The study was comprised of 85 subjects in the late mixed dentition. Thirty-five subjects had PDCs (either unilateral or bilateral) identified on the panoramic radiograph (PDC group), and 50 subjects presented with a normal pathway of upper permanent canine eruption as assessed on panoramic radiographs (No-PDC group). Linear and angular measurements on the lateral cephalograms concurrent with panoramic radiographs were compared between the PDC and No-PDC group statistically. RESULTS: All angular measurements that incorporated the main axis of the canine (to Frankfort horizontal, to the palatal plane, or to the axis of the central incisor) were significantly smaller in the PDC group (p<0.001). In terms of linear measurements, both the distance from the tip of the canine to the vertical axis of the central incisor parallel to Frankfort horizontal and the distance from the tip of the canine to the anterior alveolar ridge parallel to Frankfort horizontal showed significantly larger values in the PDC subjects than in normal controls. On the contrary, the vertical distance from the tip of the canine to the functional occlusal plane did not reveal any significant difference between the PDC and the No-PDC group. CONCLUSIONS: Early diagnosis of PDC is essential in order to avoid the occurrence of final canine impaction. If 3-D images of a displaced canine cannot be acquired, a lateral cephalogram can be a useful tool for the early detection of PDC in the late mixed dentition. The angle between the vertical axis of the canine and the palatal plane demonstrate diagnostic value when assessing PDCs. Values for this angle smaller than 102 degrees can indicate the presence of PDC.

Skeletal and dental outcomes of a new magnetic functional appliance, the Sydney Magnoglide, in Class II correction.

INTRODUCTION: The purpose of this prospective study was to evaluate the dentoskeletal effects of a new magnetic functional appliance, the Sydney Magnoglide (Macono Orthodontic Lab, Sydney, Australia), after both active treatment with the appliance and comprehensive fixed appliance therapy, compared with a group of untreated Class II controls. METHODS: Thirty-four consecutively treated Class II Division 1 patients treated with the Sydney Magnoglide followed by fixed appliances were compared with 30 untreated Class II controls with the same initial dentoskeletal Class II features and matched for age and sex. Lateral cephalograms were taken before treatment, immediately after functional appliance therapy, and after comprehensive fixed appliance therapy. Cephalometric analyses included the Pancherz analysis and linear and angular measurements. The comparisons were made with Student t tests (P <0.05). There were 3 dropouts, for a final sample for statistical analysis of 31 subjects. RESULTS: There was no statistically significant difference between the treated and control groups before treatment. Treatment with the Sydney Magnoglide and comprehensive fixed appliance therapy normalized the overjet and corrected the Class II relationship in all treated subjects. The ANB angle showed a reduction of 1.0°, as opposed to an increase of 0.3° in the untreated controls, and was associated with a statically significant improvement in the SNB angle (P <0.05). There was a significant gain of 2.3 mm in mandibular length in the treated group compared with the control group (P <0.01). CONCLUSIONS: The outcomes of this prospective study demonstrate that the compliance-free Sydney Magnoglide is an effective functional appliance for Class II correction.

Healing of gingival recession following orthodontic treatment: a 30-year case report.

This case report describes the healing of gingival recessions on mandibular incisors resulting from orthodontic treatment of a deep bite malocclusion at a 30-year follow-up observation. The marked improvement in the severe recessions was a consequence of the elimination of the direct trauma, orthodontic intrusion of the affected teeth, and subsequent creeping attachment over time. No periodontal treatment was performed before or after orthodontic treatment.

Mandibular second molar eruption difficulties related to the maintenance of arch perimeter in the mixed dentition.

INTRODUCTION: In this prospective longitudinal study, we compared the prevalence of mandibular second molar eruption difficulties in patients treated with appliances to maintain mandibular arch perimeter. Other independent variables (age, molar angulation, space-width ratio, treatment time, and sex) were tested for their value as predictors of eruption difficulty. METHODS: Three hundred one patients and subjects were divided into 4 groups: patients treated with a Schwarz appliance, patients treated with a mandibular lingual holding arch, patients treated with a combination of both appliances, and subjects who received no treatment (controls). Logistic regression analysis was used to determine the statistical significance of the possible predictors of eruption difficulty. Panoramic radiographs were analyzed at 2 times--before and after treatment. The radiograph before treatment was evaluated for the angulation of the mandibular second molars and space available for these unerupted teeth. The radiograph after treatment was used to determine the incidence of mandibular second molar eruption difficulty. RESULTS: All 3 treatment groups had higher incidences of mandibular second molar eruption difficulty when compared with the controls; the increased prevalence was significant for the protocols incorporating the Schwarz appliance. Initial molar angulation, space-width ratio, age, and sex of the patient were not significant predictors of disturbances in the eruption pattern of the mandibular second molars. CONCLUSIONS: Orthodontic appliances intended to maintain mandibular arch perimeter in the mixed dentition increase the probability of eruption disturbances of the mandibular second molars. Clinicians should monitor these patients carefully to prevent impaction of the second molars.

Dental anomalies in the primary dentition and their repetition in the permanent dentition: a diagnostic performance study.

This study investigated the recurrence in the permanent dentition of dental anomalies of the primary dentition. A sample of 189 subjects (100 males, 89 females, mean age of 5 years and 7 months) with anomalies of primary teeth (tooth hypodontia, supernumerary teeth, geminated teeth, and fused teeth) was selected and re-analyzed at a mean age of 11 years and 2 months for the recurrence of the dental anomalies in the permanent dentition. As a control group, 271 subjects (123 males, 148 females) without dental anomalies in the primary dentition were selected. The recurrence in the permanent dentition of the dental anomalies in the primary dentition was evaluated by measures of diagnostic performance. The results showed high values for the repetition of hypodontia (positive likelihood ratio = 102.0); low score for the repetition of hyperdontia (positive likelihood ratio = 6.5); low positive likelihood ratio (9.1) for gemination of primary teeth resulting in supernumerary permanent teeth; high positive likelihood ratio (47.0) for fusion of primary teeth followed by missing permanent teeth. Dental anomalies in the primary dentition are associated with an increased likelihood of anomalies of the succedaneous permanent.

Dentition phase and chronological age in relation to gingival crevicular fluid alkaline phosphatase activity in growing subjects.

OBJECTIVE: Identification of skeletal maturation phases is of primary importance in terms of individual responsiveness to nearly all dentofacial orthopaedic treatments. In this regard, dentition phase and chronological age are still widely used to define the timing of and responsiveness to orthodontic treatments. Recently, gingival crevicular fluid (GCF) alkaline phosphatase (ALP) activity has been shown to be a reliable biomarker of skeletal maturation in growing subjects. Here, for the first time, circumpubertal dentition phases and chronological age were evaluated for correlations with GCF ALP activity, as a biomarker of skeletal maturation. MATERIALS AND METHODS: Eighty-five healthy growing subjects (51 females, 34 males; mean age, 11.7±2.3 years) were enrolled into this double-blind, prospective, cross-sectional-design study. Samples of GCF were collected from each subject at the mesial and distal sites of both of the central incisors, at the maxillary and mandibular arches. Their dentition phases were recorded as intermediate mixed, late mixed, or permanent. GCF ALP enzymatic activity was determined spectrophotometrically. RESULTS: The dentition phases showed median GCF ALP activities from 42.0 to 67.5 mU/sample. Although these were slightly greater for the permanent dentition, no significant differences were seen. Also, the chronological age did not correlate significantly with GCF ALP activity, and no significant differences were seen between maxillary and mandibular sites in any of the comparisons. CONCLUSIONS: Assessment for treatment timing of dentofacial disharmonies in individual patients that require monitoring of their skeletal maturation phases should not rely on their circumpubertal dentition phase and chronological age.

Mesial rotation of upper first molars in Class II division 1 malocclusion in the mixed dentition: a controlled blind study.

OBJECTIVE: To compare the amount of upper molar rotation in subjects with Class II Division 1 malocclusion and subjects with normal occlusion in the intermediate and late mixed dentition phases. MATERIALS AND METHODS: Dental cast measurements were performed in a sample of 120 Class II Division 1 subjects (CL2 group, 67 females and 53 males, mean age 9.4±1.1 years), and in a sample of 58 Class I subjects (CL1 group, 34 females and 24 males, mean age 9.7±1.2 years). Independent sample t tests were used for statistical comparisons (P<.05). RESULTS: The amount of upper molar rotation was significantly greater in CL2 group when compared with CL1 group as assessed by both the mesial and buccal molar cusp angles. No differences were found with regard to upper or lower arch depths, or upper intercanine width. CL2 group showed a significant deficiency in upper intermolar width along with a significant posterior transverse interarch discrepancy when compared with CL1 group. CONCLUSIONS: Subjects with Class II malocclusion in the mixed dentition present with mesial upper molar rotation in about 84% of the cases. The correction of molar rotation may provide between 1 and 2mm of gain in arch perimeter and of improvement in molar relationships per side in 5 out 6 Class II patients.

Efficacy of 2 finishing protocols in the quality of orthodontic treatment outcome.

INTRODUCTION: The objectives of this prospective clinical study were to evaluate the quality of treatment outcomes achieved with a complex orthodontic finishing protocol involving serpentine wires and a tooth positioner, and to compare it with the outcomes of a standard finishing protocol involving archwire bends used to detail the occlusion near the end of active treatment. METHODS: The complex finishing protocol sample consisted of 34 consecutively treated patients; 1 week before debonding, their molar bands were removed, and serpentine wires were placed; this was followed by active wear of a tooth positioner for up to 1 month after debonding. The standard finishing protocol group consisted of 34 patients; their dental arches were detailed with archwire bends and vertical elastics. The objective grading system of the American Board of Orthodontics was used to quantify the quality of the finish at each time point. The Wilcoxon signed rank test was used to compare changes in the complex finishing protocol; the Mann-Whitney U test was used to compare changes between groups. RESULTS: The complex finishing protocol group experienced a clinically significant improvement in objective grading system scores after treatment with the positioner. Mild improvement in posterior space closure was noted after molar band removal, but no improvement in the occlusion was observed after placement of the serpentine wires. Patients managed with the complex finishing protocol also had a lower objective grading system score (14.7) at the end of active treatment than did patients undergoing the standard finishing protocol (23.0). CONCLUSIONS: Tooth positioners caused a clinically significant improvement in interocclusal contacts, interproximal contacts, and net objective grading system score; mild improvement in posterior band space was noted after molar band removal 1 week before debond.

Stability of rapid maxillary expansion and facemask therapy: a long-term controlled study.

INTRODUCTION: The aim of this prospective controlled study was to evaluate the long-term effects of rapid maxillary expansion and facemask therapy in Class III subjects. METHODS: Twenty-two subjects (9 boys, 13 girls; mean age, 9.2 years ± 1.6) with Class III disharmony were treated consecutively with rapid maxillary expansion and facemask therapy followed by fixed appliances. The patients were reevaluated at the end of the 2-phase treatment (mean age, 14.5 years ± 1.9) and then recalled about 8.5 years after the end of rapid maxillary expansion and facemask treatment (mean age, 18.7 years ± 2.1). Two groups of controls with untreated Class III malocclusion were used for statistical comparisons of the short-term and long-term intervals. Statistical comparisons were performed with the Mann-Whitney U test. RESULTS: In the long term, no significant differences in maxillary changes were recorded, whereas the treatment group showed significantly smaller increases in mandibular protrusion. The sagittal maxillomandibular skeletal variables maintained significant improvements in the treatment group vs the control groups. CONCLUSIONS: In the long term, rapid maxillary expansion and facemask therapy led to successful outcomes in about 73% of the Class III patients. Favorable skeletal changes were mainly due to significant improvements in the sagittal position of the mandible.

Outcomes of two-phase orthodontic treatment of deepbite malocclusions.

OBJECTIVE: The objective of this prospective controlled study was to assess the outcomes of two-phase treatment of deepbite patients revaluated at the end of circumpubertal growth, 1 year after the end of a phase-2 treatment. MATERIALS AND METHODS: A sample of 58 subjects with deepbite (mean age 9.7 years, overbite greater than 4.5 mm) was treated consecutively with a two-phase protocol. Lateral cephalograms were taken before treatment (T1), at the completion of phase 1 (T2), and 1 year after the completion of phase 2 with fixed appliances (T3, mean age 15.8 years). The T1-T2, T2-T3, and T1-T3 changes were compared with those of the 29 subjects (mean age at T1 = 9.1 years) with untreated deepbite (t-tests for independent samples). Prevalence rates for improved overbite during the T1-T3 interval and for corrected overbite at T3 were contrasted in the treated vs untreated groups (z tests on proportions). RESULTS: Overbite was reduced by 1.9 mm in the treated group as a result of overall treatment; this group also displayed a significant reduction in the interincisal angulation (-6.6°) due to a significant proclination of upper incisors (4.1°) and a significant increase in the projection of the lower incisors (2.0 mm). CONCLUSIONS: The average amount of deepbite correction 1 year into retention was modest, and it was mainly due to a significant proclination of the incisors. The prevalence rate of subjects with a corrected overbite in the treated sample at T3 (74%) was not significantly different from that of the untreated sample (52%).

Longitudinal growth changes in subjects with deepbite.

INTRODUCTION: This study was a cephalometric evaluation of the growth changes in untreated subjects with deepbite at 4 time points during their developmental ages (from the early mixed dentition to the permanent dentition, and from the prepubertal phase to young adulthood). METHODS: A sample of 29 subjects with deepbite (overbite >4.5 mm) was followed longitudinally from about 9 through about 18 years of age. Dentofacial changes at 4 times, defined by the cervical vertebral maturation method, were analyzed on lateral cephalograms. Nonparametric statistical analysis was used for comparisons. RESULTS: Overbite improved on average by 1.3 mm between the first and last measurements; it worsened significantly during the prepubertal period, but it improved significantly at the pubertal growth spurt. From the prepubertal ages through young adulthood, overbite improved in 83% of the subjects and self-corrected in 62% of the subjects. Improvements in overbite were related to the initial amount of maxillary incisor proclination. The significant improvement in overbite during the adolescent growth spurt depended on the amount of vertical growth of the mandibular ramus and the eruption of the mandibular molars. CONCLUSIONS: Subjects with deepbite showed worsened occlusal conditions during the prepubertal and mixed dentition phases, but had significant improvements thereafter. Improvements in overbite cannot be predicted on the basis of skeletal vertical relationships. These results provide useful indications for appropriate orthodontic treatment timing for an increased overbite.