An Evaluation of Upper and Lower Pharyngeal Airway Width, Tongue Posture and Hyoid Bone Position in Subjects with Different Growth Patterns.

INTRODUCTION: It is important to evaluate the position of the hyoid bone in relation to the tongue at the beginning of orthodontic treatment so that during the treatment, its position may be directed hence overall impact on airway could be assessed. AIM: The aim of this study was to evaluate the upper and lower pharyngeal airway dimensions, posture of tongue and hyoid bone position in young adults with different growth patterns. MATERIALS AND METHODS: Sample size of the study included 90 post-adolescent subjects, within the age range of 18-32 years. Based on the different growth pattern of the face, subjects were divided into Group I (n=30; average growth pattern), Group II (n=30; horizontal growth pattern) and Group III (n=30; vertical growth pattern). Lateral cephalogram were traced and analysed manually by the same investigator for evaluation of upper and lower pharyngeal airway, tongue posture and hyoid bone position. The intergroup comparison of upper and lower pharyngeal airway dimensions, posture of tongue and hyoid bone was performed with one-way ANOVA test. RESULTS: The results showed that upper oropharyngeal widths were significantly different in different facial skeletal patterns (p=0.00). Subjects with vertical skeletal pattern have significantly narrower upper airways than those with horizontal skeletal pattern (p= 0.025). There was significantly higher difference in position of dorsum of the tongue in vertical growth pattern group (p=0.00). The hyoid bone was positioned farther from the mandibular symphysis in brachyfacial subjects, reflected by the larger H-RGN (Hyoid- retrognathion) values compared with the dolichofacial and normal subjects (p=0.044). CONCLUSION: The upper oropharyngeal width was found to be narrower in subjects with vertical growth pattern. The dorsum of the tongue is seen to be placed higher in subjects with vertical growth pattern. The hyoid bone was more inferiorly and posteriorly positioned in subjects with horizontal growth pattern. Variations are seen in upper and lower oropharyngeal widths, posture of the tongue and hyoid bone position in all the growth patterns.

Estimation of Release of Nickel and Chromium by Indian Made Orthodontic Appliance in Saliva.

INTRODUCTION: With increasing use of Indian made orthodontic materials, need was felt to know nickel and chromium release from these material. MATERIALS AND METHODS: This study was conducted on simulated appliances consisting of brackets (022″Roth, Modern orthodontics, Ludhiana, India), from second premolar to central incisor, buccal tube and 0.019×0.025- inch SS arch wires secured with SS ligatures. Immersion was done in artificial saliva. Samples were analysed to using Atomic Absorption Photospectrometer (GVC ScientificEquipment Pvt. Ltd Australia) at AES Laboratories (P) Ltd., Noida India on 1(st), 7(th), 14(th) and 28(th) day. RESULTS: SPSS (ver 17, Inc., Chicago, Illinois, USA) was used toperform the statistical analysis. Descriptive statistics i.e. median and 25 and75 percentiles were used. Peak nickel release was on 7(th) day and subsequently declined over 14(th) and 28(th) day. The peak level of chromium concentration was on 14(th) day, which declined thereafter. CONCLUSION: Average daily release of nickel and chromium over a period of one month was 97.368 µg/day and 47.664 µg/day respectively. The estimated release rates were approximately 32% and 16% of the reported average daily dietary.

Establishment of soft tissue norms for the north Indian population based on laymen perception.

In this study we aimed to determine the soft tissue norms for the North Indian population based on the laymen perception of facial esthetics and to test the hypothesis that there are racial differences in cephalometric measurement between North Indians and White Americans norms. Two sets (Facial frontal and profile photographs) of 170 standardized facial photographs (76 males and 94 females in the age group of 18-28 years) were taken. A panel of judges which consisted of 20 laymen evaluated the photographs on the visual analogue scale to select a sample of 120 subjects (60 males and 60 females), which included individuals with esthetically pleasing appearance. Digital lateral cephalograms were made and anatomic landmarks were identified directly on the digital images. Seventeen soft tissue variables taken from Subtenley's, Holdaway's, Ricketts and Legan's analysis were calculated electronically using the Dolphin (version 9) software package. Most measurements were similar to the white American norms, some differences were noticed in nasal prominence, basic upper lip thickness, and 'H' angle measurements. The independent-sample t test was used to compare the measurement differences of the North Indian men and women. North Indian males have relatively prominent and thicker upper lip, and increased basic upper lip thickness than the females. Lower lip was found to be more protrusive in females than in males.

Transmigration of impacted mandibular canines and its association with malocclusion and morphology: an analysis of seven cases.

AIM: To investigate the morphologic parameters associated with cases of transmigrating mandibular canines. METHODS: The orthodontic records of 3,500 patients were examined for the presence of transmigrating mandibular canines. Lateral cephalograms and study casts were analyzed for skeletal and dental parameters. Observations were made as to the sex and age of the subject, and side, location, and type of migration were recorded from the panoramic radiograph. RESULTS: Seven cases were found to be associated with transmigrating mandibular canines. These included four females and three males between the ages of 14 and 21 years. All canines were unilateral, with three each of type 1 and type 2 and one type 4 case. Retained primary canines and second molars were observed in four cases. Two cases were associated with hypodontia and palatally displaced maxillary canines. Six cases had Class II malocclusions, with 5 cases having deep bite (> 40%) and a deep curve of Spee. Five cases showed increased lower anterior facial height and excess tooth material. CONCLUSION: Dental Class II malocclusion with deep bite, deep curve of Spee, excess tooth material, and increased lower anterior facial height indicating an increase in space available apical to the mandibular incisors (resulting in a loss of canine guidance) may be predisposing factors in the etiology of the transmigrating canine.