Análise das tensões ao redor de implantes após aparafusamento de infraestruturas soldadas a Laser e a Tig / Analysis of stresses around implants after screw infrastructure and Tig welded Laser

Objetivo: avaliar por meio da fotoelasticidade, as tensões geradas ao redor de implantes após o aparafusamento de estruturas confeccionadas por soldagem a Laser ou a TIG de barras cilíndricas de Cobalto-Cromo. Metodologia: foi realizado um estudo experimental a partir de um modelo de trabalho com dois implantes rosqueáveis. Nele foram realizadas a união dos UCLAs calcináveis à barra metálica, ambos de Cobalto-Cromo, por meio de soldagens à Laser(Grupo 1) e a TIG (Grupo 2), para confecção das amostras. Em seguida, sobre um modelo fotoelástico foram parafusadas as estruturas metálicas com torque manual de 20 Ncm, levadas ao polariscópio circular e submetidas a fotografias digitais padronizadas .Resultados: foi constatada a presença de tensões em ambos os grupos, contudo, a solda TIG exibiu maior número de franjas entre os implantes e nas cervicais distais. Conclusão: a estrutura confecciona por soldagem a Laser gerou menos tensões ao redor dos implantes que a confeccionada por soldagem a TIG para as infraestruturas de Co-Cr.

Aim: evaluate by using photoelasticity, the influence of laser welding or TIG welding of cylindrical rods of Cobalt-Chromium in the generation of tensions around implants. Methodology: using a working model with two screw implants, Cobalt-Chrome frameworks were made by laser welding method (Group 1) and TIG method(Group 2). Then, on a photoelastic model were bolted steel structures with manual torque of 20 Ncm, put to the circular polariscope and subjected to standardized digital photographs.Results: confirmed the presence of tensions in both groups, however, the TIG welding exhibited higher number of fringes between the implants and the distal neck. Conclusion: laser welding framework has generated less tension on the implants that the TIG welding for Cobalt-Chrome framework.

The influence of mandibular implant-retained overdentures in masticatory efficiency.

OBJECTIVE: To evaluate the masticatory efficiency of patients rehabilitated with conventional dentures (CDs) or implant-retained mandibular overdentures. BACKGROUND: Despite the evident benefits of implants on mastication as assessed by subjective patient-based outcomes, the extent of implant overdenture treatment effect on food comminution is not well established. MATERIALS AND METHODS: A randomised clinical trial was carried out with 29 completely edentulous patients divided into two groups. The first group was rehabilitated with a mandibular overdenture retained by two splinted implants with bar-clip system, while the second group was rehabilitated with a mandibular CD. Both groups also were rehabilitated with maxillary CDs. Masticatory efficiency and patient satisfaction were assessed 3 months after denture insertion. Masticatory efficiency was evaluated through the colorimetric method with the beads as the artificial test-food. Comparisons for masticatory efficiency and patient satisfaction were performed using Student's t-test (α = 0.05). RESULTS: No significant statistical difference was found for masticatory efficiency (p = 0.198). Patient overall satisfaction was significantly higher for the mandibular overdenture (p < 0.001). In addition, mandibular overdenture patients were significantly more satisfied with chewing experience (p < 0.05) and retention of the lower denture (p < 0.005). CONCLUSION: The results of this study suggest that mandibular overdenture significantly improves chewing experience, although limited effect on masticatory efficiency has been observed.

Solução protética para implantes mal posicionados: relato de caso clínico / Prosthetic solution for misplaced implants: a case report

Reabilitações protéticas sobre implantes ainda é um desafio para Odontologia. Existem situações em que os implantes são colocados em locais não compatíveis com o posicionamento dos dentes no arco, sendo necessário utilizar compensações protéticas capazes de corrigir essa dificuldade. Este trabalho tem como objetivo, relatar um caso clínico que apresenta uma opção protética para compensar o mau posicionamento dos implantes, pelo uso de uma mesoestrutura metálica. O paciente apresentava uma deformação óssea na região anterior de maxila onde foram instalados quatro implantes, posicionados de tal forma que os acessos aos parafusos protéticos ocorriam em áreas estética e biomecanicamente desfavoráveis. Portanto, foi planejado a confecção de uma mesoestrutura metálica, alterando a região de acesso aos parafusos protéticos, o que proporcionou ótimo resultado estético e satisfação do paciente.

Prosthetic rehabilitation on implants is still a challenge for Dentistry. There are situations where the implants are placed in locations that are not compatible with the positioning of the teeth in the arch, prosthetic compensation is necessary to be able to fix this problem. This study aims, report a clinical case that presents a prosthetic option to compensate the poor positioning of implants, by using a metallic mesostructure.The patient had a bone deformation in the anterior maxilla where four implants were installed, positioned so that access to prosthetic screws occurred in areas aesthetics and biomechanically unfavorable. So it was planned the construction of a metallic mesostructure, changing the area of access to prosthetic screws, which provided excellent aesthetic results and patient satisfaction.

Selection of mandibular major connector based on a conventional impression technique

The selection of the mandibular major connector of a removable partial prosthesis depends on the distance between the floor of the mouth and free gingival margin, height of the lingual frenum,presence of mandibular tuberosity, mobility of anterior teeth, major connector used in a previous denture and patient’s opinion, slope and retentivity of alveolar bone. However, the dental technicianrather than the dentist often selects the major connector in the cast model. Aim: To determine whether there is a difference between selecting the mandibular major connector clinically or in thecast model as determined by a conventional impression technique using alginate and a universal metallic tray. Methods: The sample was composed of 64 patients under treatment at the Departmentof Dentistry of the Federal University of Rio Grande do Norte. The distance between the floor of the mouth and the free gingival margin of the remaining elements was measured with a millimeterperiodontal probe in the oral cavity and in the cast models. Results: The mean clinical distance between the free gingival margin and the floor of the mouth was 7.39 ± 2.13 mm, in contrast to themean distance found in the models (9.03 ± 1.36). The Mann-Whitney test showed a significant difference (p < 0.001) between the two measures. Conclusions: For the adequate selection ofthe mandibular major connector, the distance between the gingival margin and the floor of the mouth must be measured clinically when using the conventional impression technique.