Correlation of mandibular third molar orientation and available retromolar space with arch length discrepancy in subjects with different growth pattern.

Aim and Objective: To evaluate, compare, and correlate the mandibular third molar orientation and available retromolar space with arch length discrepancy in subjects with skeletal class II malocclusion and different growth pattern. Material and Method: A total of 250 patients (age >18 yrs) having skeletal class II malocclusion (based on YEN angle and WITS appraisal) were divided into two groups. Both the groups (Group I with erupted mandibular third molars {N = 150} and Group II with impacted mandibular third molars {N = 100}) were subdivided into subgroups IA (n = 71), IB (n = 19), IC (n = 71) and Group IIA (n = 54), IIB (n = 30) and IIC (n = 16) for normo-, hypo- and hyperdivergent growth patterns, respectively (based on Jarabak ratio and Sn-Go-Gn angle). Four parameters, that is, retromolar space, width of third molar, third molar angulation, and mandibular incisor angulation were measured on orthopantomogram whereas arch length discrepancy was calculated with the help of lateral cephalogram and study model. Intragroup, intergroup comparisons (using unpaired Student's 't' test), and Pearson's correlation coefficient for assessed parameters were obtained. Result: Third molar angulation and retromolar space were significantly higher in Group I than in Group II (hyperdivergent pattern of Group II had highest value). The width of third molar was less than retromolar space in Group II and vice versa for Group I. Mandibular incisor angulation and arch length discrepancy were more in Group II than in Group I, but difference was statistically nonsignificant. Strong positive correlation was observed for mandibular third molar angulation and available retromolar space in normo- and hyperdivergent growth patterns. Conclusion: Lack of retromolar space along with increased amount of arch length discrepancy and mandibular incisor angulation is responsible for increased chances of third molar impaction in some subjects with class II malocclusion.

Predictive accuracy of estimating mandibular growth potential by regression equation using cervical vertebral bone age.

INTRODUCTION: The maturational changes both in size and shape of cervical vertebrae had been widely used not only to assess skeletal maturity but also to predict the same using regression equation. Thus, the aim of this cross-sectional study was to check the predictive accuracy of estimating mandibular growth potential in the North Indian population by regression equation of Mito et al. MATERIALS AND METHODS: A total of 200 subjects divided into two groups, Group I had 100 adult subjects (18-20 years) and Group II had 100 young subjects (9-14 years) were subdivided according to the gender (50 subjects in each group). Seven linear parameters on cervical vertebral bodies of C3 and C4 were measured to derive cervical vertebral age and applied to the regression equation to estimate the mandibular growth potential in Group II. The mandibular length was measured for both the groups from Co-Gn. The mean value of the actual mandibular length in Group I was statistically evaluated against the corresponding mean value of the predicted mandibular growth potential of Group II. RESULTS: The actual mandibular length (Group I) and calculated mandibular length obtained by adding mandibular growth potential (from regression equation) to the mandibular length of Group II did not differ significantly for both males and females. Chronological age showed a statistically significant difference and poor correlation with bone age, in Group II. CONCLUSION: The regression equation of Mito et al. using cervical vertebral bone age has proven to be applicable and accurate in predicting mandibular growth potential in growing young Indian individuals and can be of diagnostic and prognostic value in growth modification procedures in Orthodontics.

Ortho-surgical management of skeletal Class III malocclusion.

Class III malocclusions are considered to be one of the most difficult problems to treat. Establishment of the treatment plan is based on the efficacy and thoughtful application by the clinician and easy acceptance by the patient. We are presenting a case report of an adult male patient with skeletal Class III malocclusion who was treated by orthosurgical approach in Department of Orthodontics in collaboration with Department of Oral and Maxillofacial Surgery. The treatment was complete with a positive overbite and acceptable occlusion and satisfactory facial esthetics using a combination approach.

Cephalometric norms for orthognathic surgery in North Indian population using Nemoceph software.

BACKGROUND: Cephalometric norms, useful in providing guidance to orthodontist during diagnosis and treatment planning are subjected to variability in morphologic characteristics in different ethnic and racial groups, hence norms established for one population group are not applicable for all. AIMS AND OBJECTIVES: To compare and correlate the established hard tissue cephalometric norms for orthognathic surgery (COGS analysis) given by Legan and Burstone with norms obtained for North Indian population. METHODS: Pre-treatment digital lateral cephalograms of 100 orthodontically untreated subjects having pleasing profile and normal occlusion in the age range of 18-25 yrs (mean age of 21 ± 2.62 years) were selected. 16 linear and 6 angular hard tissue parameters of COGS analysis were analyzed using nemoceph software for the males and females separately. The data obtained were compared with previously established norms for Orthognathic Surgery using SPSS Version 15.0. RESULTS: North Indian males and females had smaller anterior cranial base length with prognathic maxilla and mandible, protrusive chin with poor chin form, decreased facial height, decreased posterior maxillary height with anticlockwise rotation of mandible, increased anterior and posterior maxillary dental heights, decreased ramal and corpus length, clockwise rotation of occlusal plane, presence of sagittal discrepancy between maxillary and mandibular denture bases in comparison to Caucasian males and females respectively. North Indian females had more proclination of mandibular incisors than Caucasian females. Sexual dimorphism was also evident in the present study with males exhibiting significantly larger cranial base length, greater middle third facial height and posterior maxillary height, counterclockwise rotation of mandibular plane, greater anterior and posterior mandibular dental heights and longer ramal and corpus length in comparison to females. CONCLUSION: North Indian population showed significant differences in facial morphology as compared to Caucasians population. Sexual dimorphism was also evident in North Indian populations. Thus the need to develop separate Orthognathic Surgical norms for better treatment planning of North Indian population is justified.

Double bonding system for deeply impacted tooth--a technic clinic.

Close eruption technique is preferred in deep, buried, intraosseous and labially impacted teeth to provide healthy and fuinctional attached gingiva but in this technique failure of bonded attachment usually means, repeat exposure of the impacted tooth. This article describes an innovative method for bonding two attachments (Double Bonding System) in combination instead of one. It provides the safe and determinate system for ortho-eruption, avoid the trauma of patient from re-exposure and enhance the comfort as well the confidence of the operator.

Comparison of esthetic outcome after extraction or non-extraction orthodontic treatment in class II division 1 malocclusion patients.

INTRODUCTION: The extraction of premolars as a practical form of orthodontic therapy has been accepted for many years, but there remains a controversy regarding the effect of premolar extraction to improve esthetics as well as dentoskeletal relationship. The esthetic impact of the soft-tissue profile might play a major role in deciding on premolar extraction or non-extraction treatment, particularly in borderline patients. This cephalometric study was undertaken to compare the post-treatment soft-tissue profiles of successfully managed Class II, Division 1 malocclusions treated with either all first premolar extractions or treatment with a non-extraction therapy. MATERIALS AND METHODS: The sample consisted of 100 post-pubertal female patients of Class II Division I malocclusion. Group 1, treated with four first premolar extractions, consisted of 50 female patients with a mean age of 14 years 1 month. Group 2, treated without extractions, consisted of 50 patients with a mean age of 13 years 5 months. Pre-treatment and post-treatment lateral cephalometric radiographs were evaluated. The pre-treatment to post-treatment stage comparison and the intergroup comparison of the treatment changes were conducted between extraction and non-extraction groups of Class II malocclusion samples with t-tests. RESULTS: The soft-tissue facial profiles of the extraction and non-extraction samples were the same following active treatment except for a more retruded lower lip and a more pronounced lower labial sulcus in those patients subjected to extraction. CONCLUSIONS: The extraction or non-extraction decision, if based on sound diagnostic criteria, seems to have no systematic detrimental effects on the facial profile.

Comparative assessment of soft-tissue changes in Class II Division 1 patients following extraction and non-extraction treatment.

BACKGROUND: The extraction of teeth for orthodontic purpose has always been a controversial subject in the speciality. The aesthetics impact of the soft-tissue profile might play a key role in deciding on premolar extraction or non-extraction (NE) treatment, particularly in borderline patients. The purpose of this cephalometric study was to examine the soft-tissue treatment effects of Class II Division 1 malocclusion undergoing extraction of all first premolars in comparison with patients undergoing treatment with a NE approach. MATERIALS AND METHODS: Hundred post-pubertal female patients of Class II Division 1 malocclusion were selected. Group 1, treated with four first premolar extractions, consisted of 50 female patients with a mean age of 14 years 1 month. Group 2, treated without extractions, consisted of 50 patients with a mean age of 13 years 5 months. Pre-treatment and post-treatment lateral cephalograms of the patients were obtained. The pre-treatment and post-treatment stage comparison and the intergroup comparison of the treatment changes were conducted between extraction and NE groups of Class II malocclusion samples with t tests. The levels of significance tested were P < 0.05 and P < 0.01. RESULTS: The main soft-tissue differences between the groups at the end of treatment were a more retruded lower lip and a more pronounced lower labial sulcus in those patients subjected to extraction. CONCLUSION: In Class II Division 1 patients, the extraction or NE decision, if based on sound diagnostic criteria, seems to have no systematic detrimental effects on the facial profile.

Management of a transmigrated mandibular canine.

The purpose of this article is to report the management of a transmigrated mandibular canine with emphasis on saving the tooth as natural part rather than surgical removal of the transmigrated tooth. There are several treatment options proposed for impacted mandibular canines including surgical removal, exposure and orthodontic alignment, intra-alveolar tooth transplantation (surgical repositioning of a tooth in its alveolar socket) and observation. The technique, surgical repositioning of a tooth involves the surgical extraction of impacted tooth and fixation in the correct position in the dental arch after surgical preparation (correction) of the alveolar socket. It is especially valuable in cases of difficult-to-treat impaction. A repositioned tooth is better substitute than fixed or removable prostheses, and the technique is more cost effective than other methods. Patients with excellent oral hygiene should be considered as preferred candidates for surgical repositioning of tooth. Disadvantages include the invasiveness of surgery, the difficulty of projecting long term stability due to chances of root resorption and loss of gingival attachment.