Stress distribution and displacement in the maxillofacial complex during intrusion and distalization of the maxillary arch using miniplates versus mini-implants: a 3-dimensional finite element study.

OBJECTIVES: To three-dimensionally analyse the stress distribution and displacement pattern in the maxillofacial complex following intrusion and distalization of the maxillary arch using finite element analysis in skeletal class II malocclusion with prognathic maxilla and vertical maxillary excess using miniplates and mini-implants. MATERIALS AND METHODS: Finite Element models of a skull, Y-shaped stainless steel miniplate, mini-implant and a posted arch were generated. Three force levels (1) 200 g (2) 300 g and (3) 500 g per side were applied to the assembly. The models were pre-processed and the analysis was performed using ANSYS version 18.1 software. Alterations in von mises stress, principal maximum stress, principal minimum stress and compressive stress were analysed around the sutures and surface landmarks. RESULTS: With miniplates, there was a maximum stress concentration at the zygomatic buttress with even stress distribution at the fronto-maxillary, zygomatico-temporal, zygomatico-frontal and pterygomaxillary sutures along with anatomical landmarks such as frontal process of maxilla, ANS, Point A, prosthion and maxillary process of zygoma. First molars experienced greater distalization effects with buccal flaring when miniplates were used. With mini-implants, canine and premolars also exhibited greater distalization effects. In the root apices, lateral incisors showed increased lingual root movement with mini-implants. CONCLUSION: Miniplates provide a greater distalizing effect while mini-implants produce increased intrusive effect. The distalizing effect is greater when 500 g of force is applied using miniplates with significantly even stress distribution and displacement pattern.

Guidelines of Revised Orthodontic Practices for Establishing "New Normality" Post COVID-19 Pandemic.

The aim of this article is to shed light upon formulation of new guidelines of revised orthodontic practices in the post-pandemic era caused due to the novel coronavirus disease 2019 (COVID-19) and also to adapt to the new regulations to prevent further spread of infection. All relevant information pertaining to the area of concern was collected using electronic databases which include Google Scholar, PubMed, Cochrane, orthodontic journals, and health bodies such World Health Organization, the British Orthodontic Society, and the National Institute of Health. Post-pandemic visionary was also contemplated. Data collected through the electronic databases were studied and compiled to provide an overview of the possible modifications which could be employed to prevent crosscontamination during and after the orthodontic therapy in the -post-pandemic era. Refashioning of the dental set-up along with the formulation of new regulations have been elucidated. This review highlights that the post-pandemic orthodontic practice is a divergent layout requiring tedious clinical and environmental modifications. New categorization of patients requiring orthodontic treatments and procedural classification based on generation of aerosol must be taken into consideration. Formulation of new regulations and redesigning the clinical set-up is crucial yet essential.