Selection patterns of dietary foods in edentulous participants rehabilitated with maxillary complete dentures opposed by mandibular implant-supported prostheses: a multicenter longitudinal assessment.

STATEMENT OF PROBLEM: Documentation of long-term changes in food intake is lacking for those treated with a maxillary complete denture opposed by a mandibular, screw-retained, implant-supported fixed prosthesis. PURPOSE: The purpose of this study was to evaluate the selection patterns of dietary foods over 5 years for edentulous participants treated in a multicenter prospective clinical trial that compared cast alloy versus laser-welded titanium frameworks of an implant-supported prostheses opposed by maxillary complete dentures to rehabilitate edentulous participants. MATERIAL AND METHODS: The study assessed data from a multicenter prospective clinical trial that followed edentulous participants from an initial baseline of wearing existing complete dentures to implant placement, restoration with a mandibular implant-supported prosthesis opposed by a maxillary complete denture, to follow-up assessment of these treatments over 5 years. The 32 participants in the cohort were treated at 5 of 9 participating centers. The data collected included 2 dietary forms, a standardized 4-day food diary form, and a dietary habits questionnaire. Each participant completed forms before entering into treatment (control) and at the 1- and 5-year follow-up assessment after being treated with a maxillary complete denture opposing a mandibular complete-arch fixed implant-supported prosthesis. Descriptive statistics were calculated for each measure at each assessment point. Regression analysis and the Sign test were used to calculate change in the participants' nutritional status (α=.05). RESULTS: Among the findings, it was noted that difficulty in masticating hard, raw, and fibrous foods decreased and intake of vegetable portions increased significantly from 2.5 to 3.3 servings. Participant comfort in eating in public places and their enjoyment of eating were significantly improved from 50% of participants being uncomfortable with their prior complete denture treatment to only 4% after 5 years. CONCLUSIONS: Within the limitations of this study, it was concluded that vegetable intake and ability to masticate raw, hard, and fibrous food for these participants improved when they received a mandibular implant-supported prosthesis opposed by a maxillary complete denture. According to the analysis and findings, the overall eating experience was more pleasurable, and eating in public was more comfortable after replacement of complete dentures with a mandibular implant-supported prosthesis.

Avaliação comparativa de propriedades geradas pelos processos de soldagem TIG e brasagem em uma liga odontológica à base de Ni-Cr / Comparative assessment of properties generated by the process of TIG welding and brazing in a Ni-Cr dental alloy

O objetivo deste trabalho foi comparar, por meio de teste de microdureza e técnicas de caracterização metalúrgica, que inclui a metalografia, microscopia óptica, microscopia eletrônica de varredura (MEV) e espectroscopia por dispersão de energia (energy dispersive spectroscopy – EDS), propriedades mecânicas e metalúrgicas de juntas soldadas pelos métodos TIG e brasagem em uma liga odontológica à base de Ni-Cr (FIT-CAST SB). As regiões estudadas em cada amostra foram o metal de base (MB), a zona termicamente afetada (ZTA) e a zona de fusão (ZF). Foram confeccionados 40 corpos-de-prova cilíndricos, em forma de bastão, com 2,5mm de diâmetro e 18,0mm de comprimento, obtidos apartir de fundição odontológica por centrifugação (técnica da cera perdida). Foram separados vinte cilindros para cada técnica, que após a soldagem formaram grupos de dez amostras para cada procedimento. A microestrutura do MB apresentou-se como uma matriz de uma solução sólida à base de Ni-Cr contendo um típico arranjo dendrítico de estrutura eutética. A liga apresentou precipitados metálicos na região interdendrítica da estrutura eutética. A análise química semi-quantitativa obtida através da técnica de EDS apresentou resultados compatíveis com a composição química quantitativa fornecida pelo fabricante da liga. Na brasagem, o MB e a ZF apresentaram microestruturas distintas. A ZF apresentou uma morfologia dendrítica grosseira com a presença de precipitados e porosidades. A análise química semi quantitativa por EDS da ZF mostrou-se bastante semelhante aos resultados obtidos para o MB...

The purpose of this study was to compare, by means of microhardness testing and metallurgical characterization techniques as metallography, optical microscopy, scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS), mechanical and metallurgical properties of welded joints by TIG and brazing methods in a dental alloy based on Ni-Cr (FIT-CAST SB). The studied regions in each sample were the base metal (MB), the heat affected zone (ZTA) and the fusion zone (ZF). Forty cylindrical bodies-of-proof, stick-shaped, with 2.5mm diameter and 18.0mm in length were made from dental casting by centrifugation (lost wax technique). Twenty cylinders were used for each technique, which formed, after the welding, groups of ten samples for each procedure. The microstructure of the MB is presented as a matrix of a solid solution based on Ni-Cr with a typical dendritic arrangement of eutectic structure. The alloy presented metallic precipitates in the interdendritic region of the eutectic structure. The semiquantitative chemical analysis obtained by EDS technique showed results consistent with the quantitative chemical composition provided by the alloy manufacturer. In the brazing method, the MB and ZF showed different microstructures. The ZF showed a rough dendritic morphology with the presence of precipitates and porosities. The semiquantitative chemical analysis by EDS of the ZF had very similar results to those obtained for the MB...