Comparison of Mandibular Buccal Shelf Bone Characteristics between Two Facial Types using Cone Beam Computed Tomography

Background: Mandibular buccal shelf (MBS) offers good quality and quantity of bone for orthodontic bone screw (OBS) insertion. Despite several reports of treated patients, there are numerous variables in selecting the exact placement site for OBS placement in the MBS. There are also anatomical variations in this area which must be considered. Objectives: This study aims to measure and compare the MBS bone characteristics for OBS placement using cone beam computed tomography (CBCT) between two different facial types. Materials and Methods: Eighty CBCT samples were collected (40 samples of group A horizontal growers and 40 of group B vertical growers). Each CBCT image was reconstructed and oriented with CS 3D CBCT software. The cortical bone thickness, the slope of the MBS, and buccolingual inclination of mandibular second molar were measured and analysed. Result: Cortical bone thickness among horizontal growers was 5.23 ± 0.58 mm and among vertical growers was 4.85 ± 0.37 mm. The slope of MBS among horizontal growers was 60.83 ± 6.15 degrees and among vertical growers was 66.75 ± 6.27 degrees. In both the parameters there was a statistically significant difference between the groups. There was no significant difference between the groups for the buccolingual inclination of 2nd molar. Conclusion: Increased cortical bone thickness and the flatter slope of MBS at the 2nd molar region allows for easier placement of OBS in horizontal growers than in vertical growers

Effectiveness of an educative ergonomic plan in reducing musculo-skeletal disorders among dental practitioners / Efetividade de um plano ergonômico educativo na redução de distúrbios osteormusculares entre dentistas

Objective: Work related musculo skeletal disorders (WMSD) are very common among dental practitioners who use precise hand-wrist motions and prolonged static postures. The aim of this study was to develop an educative ergonomic plan and test its effectiveness in reducing symptoms of musculo-skeletal disorders among dental practitioners. Material and Methods: This study was conducted on a random sample of 50 dental practitioners of both genders (25 male, 25 female) practising for more than 4 years in urban Bengaluru, India and showing symptoms of neck pain, back pain or wrist pain. In the first round of the questionnaire data was collected from all 50 dentists. Next an educative ergonomic plan was developed which included simple exercises and recommendations in the form of do's and don'ts. The study population were asked to follow the guidelines given and perform the exercises given in the poster daily for a period of 3 months. Then, the questions were again asked. The differences in responses during the first stage and second stage were analyzed. Results: The use of the ergonomic plan led to a statistically significant improvement in certain ergonomic practises such as practise of changing their positions during clinical practice, keeping shoulders and arm at correct level while working and keeping instruments within hand reach. There was a statistically significant reduction in pain levels after the use of the ergonomic plan. Conclusion: The ergonomic plan in the form of recommendations and exercises were an effective tool in improving ergonomic practises and reducing the symptoms of musculoskeletal disorders among dental practitioners. (AU)

Objetivo: Distúrbios osteomusculares relacionados ao trabalho (DORT) são muito comuns entre os dentistas que usam movimentos precisos de mão e punho e posturas estáticas prolongadas. O objetivo deste estudo foi desenvolver um plano ergonômico educativo e testar sua eficácia na redução de sintomas de distúrbios osteomusculares em dentistas. Material e Métodos: Este estudo foi realizado em uma amostra aleatória de 50 dentistas de ambos os sexos (25 homens, 25 mulheres) trabalhando há mais de 4 anos na área urbana de Bengaluru, Índia e apresentando sintomas de dor no pescoço, dor nas costas ou dor no punho. Na primeira etapa do questionário foram coletados dados de todos os 50 dentistas. Em seguida, foi desenvolvido um plano ergonômico educativo que incluía exercícios simples e recomendações na forma de fazer e não fazer. Os participantes foram solicitados a seguir as orientações dadas e realizar os exercícios indicados no pôster diariamente por um período de 3 meses. Em seguida, as perguntas foram feitas novamente. Foram analisadas as diferenças nas respostas durante a primeira etapa e a segunda etapa. Resultados: A utilização do plano ergonômico levou a uma melhora estatisticamente significativa em algumas práticas ergonômicas, como a prática de mudar de posição durante o atendimento clínico, manter ombros e braços no nível correto durante o trabalho e manter os instrumentos ao alcance das mãos. Houve redução estatisticamente significativa dos níveis de dor após a utilização do plano ergonômico. Conclusão: O plano ergonômico na forma de recomendações e exercícios foi uma ferramenta eficaz na melhoria das práticas ergonômicas e na redução dos sintomas de distúrbios osteomusculares entre os cirurgiões-dentistas. (AU)

Displacement and periodontal stress analysis on palatally impacted canine - A finite element analysis

Objective: The aim of the study was to analyze the displacement and stress pattern in periodontal ligament (PDL) of palatally impacted canines (PIC) lateral incisors (LI) and first premolars (FP) adjacent to the impacted teeth when different magnitudes of orthodontic extrusion forces were applied along with variation in the inclination of the impacted teeth. Methodology: A three-dimensional finite element model of a maxilla containing a palatally impacted canine was made with three different inclinations of the palatally impacted canine (model one, model two, and model three). Forces of 50, 70, and 100 g were loaded on the impacted tooth. Results: There was steady increase in the initial rate of displacement in the three teeth when the magnitude of the force that was applied on to the PIC increased. The initial rate of displacement was more in the FP tooth as compared to LI and the impacted teeth. The von Mises stress on the PDL varied along with the variation in the inclination of the impacted canine. Conclusion: The study showed that there was variation in the displacement and the stress distribution in the impacted canine when it was placed in different angulations. The rate of displacement of the impacted teeth reduced when the crown of the palatally impacted canines (PIC) was inclined more mesial. The use of minimal forces is ideal to extrude the impacted canines as observed from the study that the PDL stress increases with increase in the magnitude of force.