Effect of the bracketless orthodontics technique and resin composite material on the biomechanical response of the upper central incisor: 3D finite element analysis

Objectives: The bracketless orthodontic treatment (BOT) is an alternative technique which indicates using an orthodontic appliance composed of wires and composite resin assisted by 3D technology. However, the biomechanical response of central incisor orthodontic movement has yet to be investigated. Thus, the aim of the present investigation was to calculate the stress magnitude in central incisor movement through 3D finite element analysis using different wire diameters (0.012”, 0.014”, and 0.016”) of nickel–titanium wire and two different resin composites (Opallis and Filtek). Materials and Methods: A 3D volume composed of enamel, dentin, cortical bone, cancellous bone, periodontal ligament, composite resin, and different orthodontic wire diameters was designed. After the modeling process, the models were exported to computer-aided engineering software divided into a finite number of elements, and a mechanical structural static analysis was conducted. Results: The stress results were plotted on colorimetric maps and in tables for comparison between the different models. The results showed that the central incisor orthodontic movement with BOT does not induce damage to the periodontal ligament, dental root, or bone tissue, regardless of the simulated orthodontic wire diameter and resin composite materials. The palatal composite resin and orthodontic wire also presented acceptable stress magnitude during orthodontic movement. Conclusion: Thus, the BOT technique promoted a suitable biomechanical response during central incisor movement regardless the resin composite.

Considerações sobre reimplantes dentários: condutas clínicas e ortodônticas frente a estas situações

Based on a literature review, the objective of this study is to establish the degree of dental analysis or root resorption that allows replanted teeth to be moved using orthodontic appliance. Some aspects of avulsion and replanted teeth such as etiology, clinical approach and prognosis are considered. It is also presented a literature review of orthodontic tooth movement. According to most authors, the replant is frequently followed by analysis that doesn't allow orthodontic movement. Nevertheless, the lack of resorption signs during a minimum period of one year allows orthodontic treatment when necessary.

The importance of orthodontic treatment for the increase of the radical overlay previsibility: Case report

Introduction: Gingival recession is established through several factors and its treatment can be planned integrating surgical procedures with the aid of orthodontic treatment. Methods: In this context, a 36-year-old woman sought dental treatment to realign the right lower central incisor. A localized gingival recession was verified, being related to poor positioning of the root. The patient had undergone previous orthodontic treatment, as well as periodontal surgical treatment, after which there was no success. Results: After the planning of the case, the dental element was reallocated through orthodontic movement and then the periodontal surgical treatment was performed. With the results obtained, the improvement of gingival recession through orthodontic and periodontal surgical treatment is discussed. Conclusions: This clinical report shows that the gingival graft, performed after tooth movement, can increase the probability of good results in reducing root exposure.

Response to Pulp Vitality Tests in Teeth Submitted to Orthodontic Movement, Adjacent to the Cleft Area

Objective: To evaluate the pulp vitality in teeth adjacent to the cleft area submitted to orthodontic movement into the alveolar graft area in individuals with complete unilateral cleft lip and palate (CUCLP). Design: Cold sensitivity, vertical, and horizontal percussion tests were conducted on the teeth adjacent to the cleft and the contralateral teeth. Setting: Endodontics Sector in the Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo (HRAC/USP). Patients: One hundred patients with CUCLP and hypodontia of the upper lateral incisor in orthodontic movement and after successful alveolar bone graft in the cleft area. Main Outcome Measures: The cleft study group (SG) was composed of 200 teeth, adjacent to the cleft area. The control group (CG) consisted of 200 contralateral teeth. Statistical analysis was performed using the chi-square test for comparisons between groups ( P < .05). Results: In the SG, 82.0% of teeth presented positive response to the cold sensitivity testing, 13.5% had negative response, and 4.5% had marked response, with statistically significant difference in relation to the CG. The vertical and horizontal percussion tests on teeth in the SG revealed the same results, in which 95.0% presented negative response and 5.0% responded positively, without significant difference compared to teeth in the CG, for both tests. Conclusions: Teeth adjacent to the cleft area presented changes in the physiological conditions of the pulp, which were observed by reduction of positive response to the cold sensitivity testing or presence of pulp hypersensitivity in cases of marked response.

Dental hypersensitivity in individuals with cleft lip and palate: Origin and therapies

Background. Dental hypersensitivity is due to the exposure of the dentin layer after wear of enamel or cementum, exposing the dentinal tubules and the nerve endings of odontoblasts within these tubules. The present study aimed to assess the factors related to dental hypersensitivity in individuals with cleft lip and palate and the most common therapy received. Methods. The medical records of 536 patients with cleft lip and/or palate (281 males, 255 females) with a mean age of 18 were analyzed in a single center. The inclusion criterion was patients reporting dental hypersensitivity from May 2015 to October 2019. The origin of dental hypersensitivity was evaluated considering orthodontic movement, periodontal diseases, and reversible and irreversible pulpitis. The therapy indicated by the dental professionals for dental hypersensitivity were recorded. Descriptive statistics were performed. Results. Of 61 teeth with dental hypersensitivity, 10 were attributed to orthodontic movement, 21 to periodontal problems, 27 to reversible pulpitis, and three to irreversible pulpitis. The most used therapies were the application of fluoride varnish and prophylaxis, dentifrice indication for dental sensitivity, free gingival grafts, pulpectomy, desensitizing agent application, conservative endodontic treatment (direct pulp protection), and restoration of non-carious cervical lesions. Conclusion. Reversible pulpitis was the most prevalent etiologic factor of dental hypersensitivity in individuals with cleft lip and palate. Dentifrices for dental sensitivity and fluoride varnish application were frequently recommended.

ATR-FTIR Analysis of Orthodontic Invisalign® Aligners Subjected to Various In Vitro Aging Treatments

Clear and removable tooth aligners for orthodontics treatments have become an increasingly popular alternative to fixed appliances. Even if protocols suggest removing aligners before eating or drinking, most patients retain them when they drink beverages. Alterations in the material during the daily use could determine a reduction in the application forces, affecting the desired orthodontic movement; the knowledge of how this material reacts when subjected to different aging processes is mandatory to establish the predictability of the orthodontic treatment. According to this, the aim of the present study was to assess a new objective approach, coupling spectroscopic and chemometric tools, to evaluate the changes occurring in Invisalign® aligners, the most widely used brand, exposed in vitro to coffee, tea, Coca Cola® and UV radiation for 24 and 48 h. In particular, ATR-FTIR spectroscopy was utilized to characterize, at the molecular level, the chemical and color modifications in the surfaces of the appliances; the obtained data were submitted to PCA and one-way ANOVA and Tukey’s multiple comparison test. Moreover, a colorimetry analysis was carried out to evaluate any changes in color and transparency. Coffee and tea samples displayed the major color changes between the tested groups. The differences highlighted in the spectral features of coffee, tea and UV-treated samples were mainly ascribable to color and transparency changes, because the chemical properties remained unaltered.