Comparison of treatment effects from total arch distalization using modified C-palatal plates versus maxillary premolar extraction in Class II patients with severe overjet.

INTRODUCTION: This study aimed to compare the skeletodental and soft tissue changes with total arch distalization using a modified C-palatal plate (MCPP) and maxillary first premolar extraction treatment in Class II malocclusion patients with severe overjet. SETTING AND SAMPLE POPULATION: The sample consisted of 46 adult patients who had Class II Division 1 malocclusion with severe overjet; 25 of them received non-extraction treatment with MCPPs (age, 22.5 ± 7.2 years), and 21 received maxillary first premolar extraction treatment (age 23.4 ± 6.5 years). METHOD: A total of 26 variables were measured on pre- and post-treatment lateral cephalograms. To evaluate the differences between pretreatment and post-treatment in each group, t tests and Wilcoxon rank-sum tests were used. To compare the amount of change between the two groups, MANOVA test was used. RESULTS: The overjet was significantly reduced in the MCPP and extraction groups by 4.8 mm and 5.4 mm, respectively. However, the two groups had no significant difference in the sagittal, vertical and angular changes of the maxillary incisors. In addition, regarding soft tissue changes, the MCPP and extraction groups showed an increased nasolabial angle of 7.5° and 9.4°, decreased upper lip to the true vertical line of 1.8 mm and 2.2 mm, respectively (P < .001). CONCLUSIONS: There was no significant difference in the skeletal changes between the MCPP and extraction groups, and the reduction in overjet was similar in the groups. These results suggest that MCPP might be a viable treatment option for total arch distalization in Class II malocclusion patients with severe overjet.

Autotransplanted premolars with incomplete root formation in a growing patient with multiple missing teeth.

A boy aged 8 years 11-months with 4 missing teeth in his mandibular arch and with a skeletal Class II pattern was treated with autotransplantation of developing premolars from his maxillary arch with the aid of temporary skeletal anchorage devices. The active treatment duration was 25 months. After treatment, he had a normal occlusion, and his profile was improved. Posttreatment records at 12 months showed stable occlusion and successfully autotransplanted premolars.

Comparison of Treatment Effects with Modified C-Palatal Plates vs Greenfield Molar Distalizer Appliances in Adolescents.

Objectives: The aim of study was to evaluate skeletodental and soft tissue treatment effects and the amount of maxillary molar distalization with modified C-palatal plates vs. Greenfield molar distalizer appliances in adolescents. Study design: The samples consisted of pre- and posttreatment lateral cephalograms collected from 39 patients with Class II malocclusion. The MCPP group was comprised of 21 patients (mean age: 11.7 ± 1.3 years) treated with MCPP appliances while the GMD group included 18 patients (mean age: 11.2 ± 0.9 years) treated with GMD. Fixed orthodontic treatment started with the distalization process in both groups. From each cephalograpm, twenty-nine variables were measured for analysis and then the two groups were compared. Descriptive statistics, a paired t-test, and multivariate analysis of variance were performed to compare the treatment effects within and between the groups. Results: There was significant treatmentrelated change in the sagittal position of the maxilla and the mandible within each group. However, there were no statistically significant inter-group differences. The mean maxillary first molar distalization was 3.96 mm in the MCPP group vs. 2.85 mm in the GMD group. Both groups showed minimal distal tipping, but the maxillary incisors were significantly extruded by 3.04 ± 0.89 mm (P < .001) in GMD group. There was no significant difference in treatment duration between the groups. Conclusions: The maxillary first molars of both the MCPP and GMD groups were effectively distalized and there were significant skeletal changes in the maxilla. However, the maxillary incisors were significantly extruded in the GMD group.

Evaluation of condyle-fossa relationships in adolescents with various skeletal patterns using cone-beam computed tomography.

OBJECTIVES: To evaluate the condyle-fossa relationship in adolescents with various skeletal patterns using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT images obtained in 120 adolescent patients were used for this study. The patients were divided into 3 groups according to 3 criteria: (1) age (early, middle, and late adolescence); (2) facial height ratio or Jarabak quotient (hyperdivergent, normodivergent, and hypodivergent); and (3) ANB classification (Class I, Class II, and Class III). Temporomandibular joint space (TMJS: AS, anterior space; SS, superior space; PS, posterior space; MS, medial space; LS, lateral space), width and depth of the condyle (MLT, mediolateral thickness; APT, anteroposterior thickness), articular slope (ArS) and vertical height of the fossa (VHF) were measured and compared using CBCT. RESULTS: Differences in condyle-fossa relationships were not significantly different between male and female adolescents, but were significantly different (P < .05) between left and right sides. The mean values showed no statistical differences according to age and skeletal pattern. Most measurements in the sagittal view showed that SS was the greatest, and the mean ratio of AS to SS to PS was 1.00 to 1.27 to 1.19, respectively. The mean values of coronal MS and LS were not significantly different. CONCLUSIONS: There were almost no statistical differences in the TMJS in adolescents across various factors except between left and right sides.

A Modified Palatal Appliance for Forced Eruption of Impacted Central Incisor.

A 9-year-old female was referred by her general dentist for an evaluation of an impacted maxillary left central incisor. Her maxillary left primary incisors showed crossbites and her right central incisor showed an edge-to-edge bite which caused gingival recession on the mandibular right central incisor. After treatment, the impacted maxillary central incisor erupted successfully. An optimal overbite and overjet were also achieved, and her gingival recession was improved.

Biomechanical analysis for total distalization of the mandibular dentition: A finite element study.

INTRODUCTION: The aim of this finite element study was to analyze and clarify the mechanics of tooth movement patterns for total distalization of the mandibular dentition based on force angulation. METHODS: Long-term orthodontic movement of the mandibular dentition was simulated by accumulating the initial displacement of teeth produced by elastic deformation of the periodontal ligament. RESULTS: Displacement of each tooth was caused by movement of the whole dentition, elastic deflection of the archwire, and clearance gap between the archwire and bracket slot. The whole dentition was rotated clockwise or counterclockwise when the line of action of the force passed below or above the center of resistance. Elastic deflection of the archwire induced a lingual tipping of the anterior teeth. It became larger when increasing the magnitude of angulation. The archwire could be rotated within the clearance gap between the archwire and the bracket slot, and thereby the teeth tipped. CONCLUSIONS: Mechanics of total mandibular distalization was clarified. Selective use of force angulation with a careful biomechanical understanding can achieve proper distalization of the whole mandibular dentition.

Improvement of facial profile by nonextraction orthodontic treatment with temporary skeletal anchorage devices and visual treatment objectives.

A 15-year-old girl with a convex profile and a retrognathic chin was referred for improvement of her profile. Nonextraction orthodontic therapy with temporary skeletal anchorage devices was used to improve her facial balance in a total active treatment time of 26 months. Her occlusion and profile were significantly improved by the treatment. Posttreatment records after 12 months showed excellent results with good occlusion and facial harmony.

Modified Surgical Stent for Accurate TAD Placement.

The development of temporary anchorage devices (TADs) has allowed for the creation of anchorage in situations where there once was none. Many studies have suggested that the most significant cause of miniscrew failure is insufficient distance between the surface of a root and the miniscrew. In order to reduce the miniscrew failure rate, a modified surgical stent has been shown to not only increase TAD insertion accuracy but also to increase TAD success rates.

Prediction of optimal bending angles of a running loop to achieve bodily protraction of a molar using the finite element method.

OBJECTIVE: The purpose of this study was to predict the optimal bending angles of a running loop for bodily protraction of the mandibular first molars and to clarify the mechanics of molar tipping and rotation. METHODS: A three-dimensional finite element model was developed for predicting tooth movement, and a mechanical model based on the beam theory was constructed for clarifying force systems. RESULTS: When a running loop without bends was used, the molar tipped mesially by 9.6° and rotated counterclockwise by 5.4°. These angles were almost similar to those predicted by the beam theory. When the amount of tip-back and toe-in angles were 11.5° and 9.9°, respectively, bodily movement of the molar was achieved. When the bend angles were increased to 14.2° and 18.7°, the molar tipped distally by 4.9° and rotated clockwise by 1.5°. CONCLUSIONS: Bodily movement of a mandibular first molar was achieved during protraction by controlling the tip-back and toe-in angles with the use of a running loop. The beam theory was effective for understanding the mechanics of molar tipping and rotation, as well as for predicting the optimal bending angles.

Treatment with Twin-block appliance followed by fixed appliance therapy in a growing Class II patient.

A girl, aged 11 years 4 months, with a skeletal Class II pattern and a severe overjet (10 mm) was treated with a Twin-block appliance. After 9 months of appliance therapy, the skeletal Class II was overcorrected. After 26 months of retention, when the occlusion was stable and the growth rate was diminishing, fixed orthodontic appliances using temporary skeletal anchorage devices were initiated. The total active treatment time with fixed orthodontic appliances was 30 months. Posttreatment records after 18 months demonstrated excellent stability: a functional occlusion and a pleasing facial balance. Cone-beam computed tomography was used to visualize temporomandibular joint adaptations after the functional and fixed orthodontic therapies.

Orthodontic treatment of a patient with severe crowding and unilateral fracture of the mandibular condyle.

A 15-year-old girl who had a unilateral condylar fracture with severe crowding in both arches was treated with 4 premolar extractions followed by orthodontic therapy with a temporary skeletal anchorage device in the maxillary arch. The total active treatment time was 21 months. Her occlusion was significantly improved by orthodontic treatment, and the range of condylar movement was also improved. Posttreatment records after 30 months showed excellent results with a good stable occlusion. The remodeling process of the condyle was confirmed with cone-beam computed tomography images.

Space closure in the maxillary posterior area through the maxillary sinus.

A common dilemma in adult orthodontic treatment is deciding how best to treat missing posterior teeth. One treatment option is to orthodontically close the space. But closure can be difficult, especially if the open space is in the maxillary posterior area, because tooth movement through the maxillary sinus is limited. The increased difficulty of moving teeth in the maxillary sinus is similar to moving a tooth in the atrophic posterior mandibular ridge. If space closure is selected as a treatment method, proper mechanics and light forces should be applied. In this article, we report movement of teeth through the maxillary sinus and discuss various implications related to orthodontic treatment in the maxillary sinus.

Timing of Class III treatment with unfavorable growth pattern.

When treating youngpatients with Class III malocclusion, factors such as timing and an accurate prediction of growth of the mandible are very important. Even though early interceptive treatment of Class III might often be successful, clinicians should be careful to not initiate early treatment with premolar extractions which will compromise the success of orthognathic surgery later due to mandibular prognathism. This case report presents an adolescent female patient who developed a severe Class III skeletal discrepancy during growth and was treated with surgery after her growth had finished.

Distal movement of the mandibular dentition with temporary skeletal anchorage devices to correct a Class III malocclusion.

This case report describes the treatment of an 18-year-old man with a skeletal Class III pattern and a full-step Class III malocclusion. The orthodontic treatment included distal movement of the mandibular dentition with temporary skeletal anchorage devices. The total active treatment time was 30 months. His occlusion and facial appearance were significantly improved by the orthodontic treatment. Posttreatment records 2 years later showed excellent results with good occlusion and facial balance.

Treatment of an impacted supernumerary tooth using limited fixed orthodontic appliances.

A 42-year and 9-month-old female with an impacted supernumerary tooth was treated with limited fixed orthodontic appliances. As seen in this case, it is possible to successfully treat impacted teeth in adults even though the most common time to treat impactions is during adolescence.