Dentoskeletal morphology in adults with Class I, Class II Division 1, or Class II Division 2 malocclusion with increased overbite.

INTRODUCTION: The treatment options for adults with increased overbite are limited to dentoalveolar changes that camouflage the condition. Because of high relapse tendency, defining the problem area is important when creating a treatment plan. This study aimed to evaluate dentoskeletal morphology in skeletal Class I and II anomalies associated with Angle Class I, Class II Division 1 (Class II/1), and Class II Division 2 (Class II/2) malocclusions with increased overbite compared with normal occlusion. METHODS: Pretreatment cephalograms of 306 patients (131 men, 175 women; overall ages 18-45 years) were evaluated. Four groups were constructed. Three groups had increased overbite (>4.5 mm): group 1 (n = 96) skeletal Class I (ANB = 0.5°-4°), group 2 (n = 85) skeletal Class II (ANB >4.5°) with Class II/1; and group 3 (n = 79) skeletal Class II with Class II/2 malocclusion. Group 4 as a control (n = 46) skeletal Class I normal overbite. Dental and skeletal characteristics of the groups were compared by sex. For statistical evaluations, analysis of variance followed by Tukey post hoc, Mann-Whitney U, and Kruskall-Wallis tests were used. Additionally correlation coefficients between overbite and skeletal/dental parameters were calculated. RESULTS: Between sexes, with regard to skeletal parameters, the men had greater values in millimetric measurements, and the women had higher SN/GoGn values. Maxillary/mandibular molar heights and the mandibular incisor heights were higher in men. In group 1, decreased lower anterior facial height (LAFH), retrusive mandibular incisors, and increased interincisal degree were determined. The maxillary molars were intrusive, whereas the vertical position of the mandibular molars and incisors in both jaws were normal. In group 2, retrognathic mandible, increased LAFH and mandibular plane angle, extrusive maxillary/mandibular incisors, protrusive mandibular incisors, and decreased interincisal degree were found. In group 3, decreased LAFH, increased interincisal degree, and retrusive incisors in both jaws were determined. There were significant negative correlations between SN/GoGN, palatal plane, and overbite in group 2 and between ANS-SN and overbite in group 3, and positive correlation between interinsical angle and overbite in all increased overbite groups. CONCLUSIONS: Dental morphology seems to be the main factor of increased overbite. Differences between groups were related primarily to inclinations and vertical positions of the incisors, rather than molar positions.

Dimensions and morphologic variations of sella turcica in type 1 diabetic patients.

INTRODUCTION: Some chronic diseases are associated with changes in the morphology of sella turcica, and type 1 diabetes is the most common chronic disease in children and adolescents. Therefore, the aim of this study was to evaluate the size and morphology of sella turcica in patients with type 1 diabetes compared with a healthy control group. METHODS: The study included 76 type 1 diabetic patients (38 boys, 38 girls; ages, 14.16 ± 2.46 years) and 76 controls (38 boys, 38 girls; ages, 14 ± 2.08 years). The groups were categorized as pubertal and postpubertal according to bone age. The length, height, and diameter of sella turcica were measured. Then the morphology of sella turcica was analyzed and categorized as normal, oblique anterior wall, bridging, double contour of the floor, irregularity in the posterior part of dorsum sellae, or pyramidal shape of the dorsum sellae. All measurements were made on tracings of cephalometric radiographs. Differences between the groups were tested with the Mann-Whitney U test. Categorical data were evaluated with the Fisher exact test, and the Bonferroni correction was made. The significance level was assigned as P <0.05. RESULTS: There was no statistically significant difference in the dimensions of sella between the diabetic patients (diameter, 12.20 ± 1.49 mm; length, 10.49 ± 1.55 mm; height, 8.07 ± 1.25 mm) and the controls (diameter, 12.45 ± 1.43 mm; length, 10.90 ± 1.73 mm; height, 8.29 ± 1.66 mm). However, diameter and length increased with age in the overall assessment. Length was greater in the postpubertal controls (11.39 ± 1.69 mm) compared with the pubertal controls (10.41 ± 1.64 mm). Diameter was greater in the postpubertal diabetic patients (1.283 ± 1.55 mm) than in the pubertal diabetic patients (11.56 ± 1.12 mm) and was specifically higher in postpubertal boys. Normal sella morphology was less common in general in the diabetic patients, particularly in the diabetic boys and diabetic pubertal boys (P <0.05). CONCLUSIONS: The measurements concerning sella were similar in the type 1 diabetic and control subjects, but dysmorphologic types were more common in diabetic patients.

Treatment effects of the Forsus Fatigue Resistant Device used with miniscrew anchorage.

OBJECTIVE: To evaluate the dentofacial effects of the Forsus Fatigue Resistant Device (FRD) used with miniscrew anchorage (FRDMS) and compare them with those of conventional FRD and an untreated Class II control group. MATERIALS AND METHODS: The sample consisted of 48 Class II subjects. Sixteen patients (13.68 ± 1.09 years of age) were treated with FRDMS, whereas 17 subjects (14.64 ± 1.56 years of age) were treated with only FRD. Also, a control sample of 15 untreated Class II subjects (14.13 ± 1.50 years of age) was constructed. Angular and linear measurements were made on 96 lateral cephalograms. Paired t, one-way analysis of variance, and Tukey tests were used for statistical analysis. RESULTS: Class I molar relationship and overjet correction were achieved in an average period of 6.5 ± 1.97 and 5.5 ± 1.80 months in the FRDMS and FRD groups, respectively. No skeletal effect was determined in both treatment groups. Greater overbite correction was found in the FRD group. Retrusion and extrusion of maxillary incisors, distalization of maxillary molars, and extrusion of mandibular molars were significant in both treatment groups. Labial tipping of mandibular incisors was significantly greater in the FRD group than in the FRDMS group. CONCLUSION: Overjet and molar correction was totally dentoalveolar. Unfavorable labial tipping of mandibular incisors was effectively minimized with the usage of miniscrews.

Comparison of the effects of modified and full-coverage thermoplastic retainers on occlusal contacts.

AIM: The purpose of this prospective study was to determine the number of contacts in centric occlusion during retention with modified and full-coverage thermoplastic Essix retainers. METHODS: This research was based on 36 patients who were randomly assigned to wear either modified (18 patients) or full-coverage (18 patients) Essix retainers. Silicone-based bite registrations were used to record occlusal contacts at the beginning (T1), end of full-time (6 months; T2), and end of night-time (3 months; T3) wear of retainers. The occlusal contacts determined in treated patients were compared with the values of 18 untreated "normal" Class I subjects. Bonferroni-adjusted Wilcoxon and Kruskal-Wallis tests were used to evaluate intra- and intergroup differences. RESULTS: Total posterior contacts increased significantly at T3 compared to T1 and T2 only in the modified Essix group. Non-ideal and total contacts on premolars, non- ideal and actual contacts on first molars, and actual contacts on second molars increased significantly at T3 in the modified Essix group. No significant increase was determined in the final total posterior contacts in the full-coverage Essix group. Actual contacts on premolars and first molars and total posterior actual contacts were significantly greater at T3 in the modified Essix group compared to the full-coverage Essix Group. Also the number of final posterior ideal contacts in the modified Essix group was greater than in the normal sample. Total anterior contacts decreased significantly in the modified Essix group, whereas they increased significantly in the full-coverage Essix group. CONCLUSIONS: Increase in posterior contacts was achieved only during night-time wear of modified Essix retainers.

Effects of the zygoma anchorage system on canine retraction.

The aim of this study was to compare the effects of the Gjessing (PG) retraction spring used with and without the zygoma anchorage system (ZAS) on canine retraction. Thirty patients, with an Angle Class I or Class II malocclusion, whose upper first premolars were scheduled for extraction, were divided into two equal groups. Group 1 comprised maximum anchorage cases (nine females and six males with a mean age of 16 years 8 months) in which the ZAS was used to improve posterior anchorage and the PG retraction springs for canine retraction. Moderate anchorage cases (10 females and 5 males with a mean age of 15 years 5 month) were included in group 2 and canine retraction was achieved using only PG retraction springs. Study models and lateral cephalometric radiographs obtained at the initial and final stages of canine retraction were used for comparison of the groups to determine the effects of zygoma anchorage on canine retraction. All measurements were evaluated statistically using a Student's t-test, 2 × 2 repeated measures analysis of variance, Bonferroni-adjusted t-test, and Mann-Whitney U and Wilcoxon tests according to the normality of the distribution of the variables. Mesial crown movement of the molars was 0.63 mm (P < 0.05) in group 1 and 1.50 mm (P < 0.001) in group 2. There was a statistically significant difference (P < 0.05) between the groups. No significant difference was observed between the groups for the rate of canine retraction or sagittal and vertical movement of the canines. The ZAS is a reliable and successful anchorage reinforcement method for canine retraction in extraction cases.

Molar distalization with a pendulum appliance K-loop combination.

SUMMARY: The aim of this study was to evaluate the dentoalveolar effects of a pendulum appliance supported buccally by a K-loop, and to compare these with a cervical headgear (CHG) group. The records of 30 patients with skeletal Class I and dental Class II malocclusions were divided in to two groups: Patients in group 1 (seven females and eight males; mean age, 15.0 +/- 3.4 years) were treated with a pendulum appliance supported with a K-loop buccally, while in group 2 (10 females and 5 males; mean age, 14.2 +/- 2.9 years), the patients were treated with CHG. Standardized lateral cephalograms and study models were taken at the beginning of treatment (T0) and at the end of distal molar movement (T1). T0-T1 changes within the groups were analysed with a paired t-test, and between the groups with a t-test. The mean amount of distalization was 4.53 +/- 1.46 mm in group 1 and 2.23 +/- 1.68 mm in group 2. The mean amount of distal tipping for group 1 was 5.13 +/- 4.90 degrees; the mean amount of mesial tipping for group 2 was 0.80 +/- 2.27 degrees. Intrusion and mesiobuccal rotation of the maxillary molars were achieved in both groups. In group 1, the amount of labial protrusion and tipping of the maxillary incisors was not statistically significant. In group 2, palatoversion and retrusion of the maxillary incisors was statistically significant (P < 0.01 and P < 0.001, respectively). The two major disadvantages of intraoral appliances, which are distal tipping of molars and loss of anchorage at the anterior teeth, were significantly decreased with the use of a pendulum appliance K-loop combination.

Effects of thermoplastic retainers on occlusal contacts.

The aim of this prospective study was to evaluate the number of contacts in centric occlusion during retention with thermoplastic retainers (Essix retainers) and in the long term. After four premolar extractions and active orthodontic treatment of 15 Class I (10 females, 5 males; mean age 17.20 +/- 1.7 years), thermoplastic retainers were used. Occlusal contacts were determined from occlusal registrations taken in centric occlusion at the beginning (T0), end (9 months of retention; T1), and after 2.5 years (T2). The occlusal contacts determined in these patients were compared with the values of 15 'normal' Class I subjects (9 females, 6 males; mean age 17.10 +/- 1.60 years) who had not undergone orthodontic treatment. Wilcoxon and a Mann-Whitney U-tests were used to evaluate intra- and intergroup differences. No significant change was observed in the number of posterior contacts during T1, whereas a significant increase was found at T2 (P < 0.01) for the second premolars (P < 0.01) and second molars (P < 0.05). Both 'ideal' and 'non-ideal' contacts increased significantly but only at T2 (P < 0.05). The number of ideally located contacts on the posterior teeth at all three periods were lower than normal values (P < 0.01); while non-ideal contacts at T1 (P < 0.05) and T2 (P < 0.01) were found more often when compared with the values of normal subjects. Only the increased number of premolar contacts at T2 was more than normal values (P < 0.01). There was no expected increase in occlusal contacts at T2; however, posterior occlusal contacts were increased at T3.

Effects of the reciprocal mini-chin cup appliance.

The aim of this prospective study was to evaluate the dentofacial effects of the reciprocal mini-chin cup (RMCC) appliance in subjects with pubertal growth and development potential (group 1) and in subjects that had completed this period (group 2). Eighteen patients (13 females, five males) with an Angle Class II division 1 and nine patients (six females, three males) with a Class II division 2 malocclusion, with mandibular dentoalveolar retrusion and optimal vertical facial dimension were included. A control group consisting of 14 subjects (nine females, five males) with pubertal growth and development potential was constructed for comparison with group 1. In both treatment groups a RMCC was used. A Class I molar relationship was achieved in an average period of 5.11 months in group 1 and 10.57 months in group 2. From lateral cephalometric tracings, beside the angular and linear parameters, eight parameters that determined the ratio of the skeletal and dental effects of RMCC were measured and statistically evaluated. A paired comparison t-test was used to assess the differences in each group and a Student's t text to evaluate the differences between the groups. In both groups, no effect of RMCC was found on either the maxilla and/or the sagittal position of the mandible. In group 1, lower anterior face height was increased more compared with group 2; the mandibular plane angle increased and the mandible developed mostly in the vertical dimension. While a Class I molar relationship and correction of the overbite and overjet were achieved in both groups, a greater correction of overjet was found in group 1. Retrusion of the upper incisors without extrusion, protrusion, or proclination of the lower incisors, distalization of the upper molars, mesialization and extrusion of the lower molars and mesialization of the mandibular dentoalveolar structures were observed in both groups. Contributions to the correction of overjet and molar relationship were mostly dentoalveolar in both groups.

Clinical evaluation of the centre of resistance of the upper incisors during retraction.

The aim of this study was to evaluate the movement of anterior teeth during retraction with a force applied through the assumed centre of resistance (CRe).Twenty-two subjects with a Class I or II malocclusion were included. Each subject had the two upper first premolars extracted, resulting in a symmetrical extraction space of at least 3 mm between the upper laterals and canines. The force was applied through the assumed CRe, located 9 mm gingival to the lateral tooth bracket. To examine the type of anterior tooth movement, 10 parameters were measured. A Wilcoxon test was used to determine the differences between pre- and post-retraction values, and a Mann-Whitney U-test to determine the mean differences between groups. In spite of the force application through the CRe, tipping of the anterior teeth was observed in 19 subjects and parallel movement in three patients. Consequently, the subjects were divided into two groups according to the location of the centre of rotation (CRo). In group 1 (nine cases), the CRo was located coronal to the root apex, and in group 2 (13 cases), apical to the root apex. Both groups showed a significant decrease in inclination (P < 0.01) and posterior crown movement (P < 0.01 for group 1 and P < 0.001 for group 2) of the anterior teeth. A significant posterior movement of the root apex was observed in group 2 (P < 0.001). Significant differences were found between the groups for anterior tooth inclination (P < 0.05) and root apex movement (P < 0.001). The reasons for these differences could not be conclusively determined. Even though experimental studies provide information regarding CRe location, factors such as bone support, root morphology and incisor inclination should be taken into consideration. The observation of tooth movement occurring during treatment and changes in treatment mechanics would be helpful in obtaining desired tooth movement.

The investigation of occlusal contacts during the retention period.

Removable retention appliances were applied to 20 treated orthodontic patients, and their occlusal contact points were determined from occlusal registrations taken at the beginning and the end of retention. Furthermore, to determine the results at the end of retention, the occlusion of 20 treated patients was compared with a control group of another 20 subjects who had an ideal occlusion. During the retention phase the number of contacts in centric occlusion increased significantly. No significant difference was observed with regard to the location of contacts. Whereas the number of ideally located contacts was similar to that in the control group, differences were observed in actual and canine contacts between the groups. At the end of retention, the balancing side contacts in lateral movements and the posterior contacts in protrusive movements were generally determined as near contacts and showed a similarity to the control group. In order to maintain the occlusal stability that is needed for the success of orthodontic treatments, ideal occlusal contacts and localization of contacts in centric and eccentric occlusion should be considered.

Effects of vertical chincap therapy on the mandibular morphology in open-bite patients.

The aim of this study was to investigate the effects of the vertical chincap on mandibular morphology and also on the dentoalveolar structures in patients with high-angle open-bite malocclusions. We examined 35 children with high-angle skeletal Class I or II open-bite malocclusions. Eighteen subjects were selected as the treatment group, and 17 were the controls. Vertical chincaps, applying 400 g on each side from beneath the anterior part of the mandibular corpus in an upward direction, were used in the treatment group for 16 hours per day over a mean period of 9 months. We studied 70 lateral cephalograms taken before and after the treatment and the control periods. The changes of 7 linear and 8 angular parameters were evaluated statistically in both groups with paired and Student t tests, respectively. Eruption of the mandibular incisors, decrease of the ramal inclination, decrease of the mandibular plane, and increase of the overbite in the treatment group compared with the control group were found to be statistically significant. Intrusion of the first molars, decrease of the gonial angle, and increase of the mandibular corpus inclination in the treatment group were contrary to the results observed in the control group; these comparisons were also found to be statistically significant. It appears that the vertical chincap is effective in treating skeletal open bite and in decreasing the gonial angle and ramus/corpus relationship.