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The coronavirus disease-2019 (COVID-19) pandemic due to the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has casted a deep impact on every aspect of the human life all over the world. The healthcare professionals dealing with the patients have been at the greatest risk of exposure. Dental practitioners fall among the highest risk practitioners because of their field of operation being around the oropharyngeal region of patients, as well as due to the risk of generation of aerosols during various dental procedures. There is a continuous urgent need of modifying the dental practice in accordance with the guidelines issued by the health authorities time to time. Meticulously planned approaches, and adequate precautions and modifications need to be introduced into dental practice. The field of orthodontics also demands a high level of practice modification in order to ensure proper infection control for patients, practitioners, and dental staff.
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Aims: This finite element study was undertaken to evaluate the pattern of stress distribution around the implant and anterior teeth during en-masse retraction in the premolar extraction case. Displacement of the teeth and play of wire in the bracket slot were also evaluated to determine the most favorable height of the power arm attached to the arch-wire. Materials and methods: A three-dimensional (3D) finite element model of the maxilla was constructed using computed tomography (CT) scan. A total of 12 models were fabricated with different heights of power arms placed distal to the canine. A retraction force of 1.5 N was applied from the implant placed between the roots of the second premolar and first molar, and the response was predicted using Analysis of Systems (ANSYS) software. Results: When power-arm height was near the center of resistance of the anterior segment, stability in the stress distribution around the implant site and anterior teeth was observed. Displacement of the teeth varied along the three planes of space with the change in power-arm height. Conclusion: For en-masse retraction, power-arm height should be kept at a level of the center of resistance. Play in the bracket slot and the archwire show a negative role in the bodily movement of anterior teeth. Clinical significance: For efficient en-masse retraction of anterior teeth, it is imperative to study the most effective site of application of force. Therefore, our study recommends certain key points to keep in mind during the attachment of the power arm and engaging wire in the bracket slot, which could benefit the orthodontist immensely. How to cite this article: Singh H, Khanna M, Walia C, et al. Displacement Pattern, Stress Distribution, and Archwire Play Dimensions during En-masse Retraction of Anterior Teeth using Sliding Mechanics: A FEM Study. Int J Clin Pediatr Dent 2022;15(6):739-744.
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BACKGROUND: Lateral cephalometric standards of normal Central Indian adults having class I occlusion and acceptable facial profile were studied using the Burstone and Legan comprehensive cephalometric analyses that are specific for orthognathic surgery. AIM: To study normal dentofacial patterns of adult population belonging to Central India. MATERIALS AND METHODS: Cephalometric radiographs of 76 Central Indian adults (38 males and 38 females) having class I occlusion with acceptable facial profile were analyzed, and the mean values of their hard and soft tissue measurements were compared with those of Caucasian adults as reported in the literature. RESULTS: The Central Indian males demonstratedgreater anterior cranial base length and ramal length and a reduced chin depth. The inclination of the upper and lower incisors was also greater. The females demonstrated greater posterior cranial base length, increased upper anterior and posterior facial heights, and an increased maxillary length. Both mandibular body and ramal lengths were increased and there was greater mandibular protrusion and a reduced chin depth. The lower incisors were found to be proclinated. CONCLUSION: This study reveals that some of the cephalometric parameters in the Central Indian population are significantly different than that of the Caucasian population, especially in the females.
