Frederico Andrade e Silva

Fracture Strength of Aged Monolithic and Bilayer Zirconia-Based Crowns.

The purpose of this study was to evaluate the effect of design and surface finishing on fracture strength of yttria-tetragonal zirconia polycrystal (Y-TZP) crowns in monolithic (1.5 mm thickness) and bilayer (0.8 mm zirconia coping and 0.7 mm porcelain veneer) configuration after artificial aging. Bovine incisors received crown preparation and Y-TZP crowns were manufactured using CAD/CAM technique, according to the following groups (n = 10): Polished monolithic zirconia crowns (PM); Glazed monolithic zirconia crowns (GM); Bi-layer crowns (BL). Crowns were cemented with resin cement, submitted to artificial aging in a chewing simulator (2.5 million cycles/80 N/artificial saliva/37°C), and tested for fracture strength. Two remaining crowns referring to PM and GM groups were submitted to a chemical composition analysis to measure the level of yttrium after aging. One-way ANOVA and Tukeys test (P = .05) indicated that monolithic zirconia crowns presented similar fracture strength (PM = 3476.2 N ± 791.7; GM = 3561.5 N ± 991.6), which was higher than bilayer crowns (2060.4 N ± 810.6). There was no difference in the yttrium content among the three surfaces evaluated in the monolithic crowns. Thus, monolithic zirconia crowns present higher fracture strength than bilayer veneered zirconia after artificial aging and surface finishing does not affect their fracture strength.

CONTRIBUIÇÃO AO ESTUDO DA PREVALÊNCIA DE BRUXISMO EXCÊNTRICO NOTURNO EM CRIANÇAS DE 2 A 11 ANOS DE IDADE

Uma grande variacao de prevalencia de bruxismo infantil e relatada na literatura (5% a 81%), dificultando o estabelecimento de parâmetros comparativos. O objetivo deste estudo foi determinar a prevalencia de bruxismo excentrico noturno (BEN) e suas caracteristicas em 213 criancas de 2 a 11 anos, sendo 130 criancas atendidas na Clinica de Odontologia Infantil da FOP-UNICAMP e 83 criancas atendidas em consultorio particular. Os dados foram coletados mediante entrevista dirigida ao responsavel pela crianca e ao seu dentista e analisados estatisticamente atraves dos testes e de Kruskal-Wallis. Os resultados mostraram uma prevalencia de BEN de 28,64% (n=61). A diferenca de frequencia entre criancas bruxomanas e nao bruxomanas nao foi significativa em relacao ao local de atendimento (FOP versus consultorio) (p>0,05). Considerando o tipo de denticao, 39,34% das criancas com dentadura decidua e 24,34% com denticao mista eram bruxomanas (p<0,05). Entre os bruxomanos (n=61), 27,87% eram criancas ansiosas e 31,15% eram hiperativas. Cinquenta e um por cento das criancas com BEN tinham problemas respiratorios e/ou alergicos. Em relacao a idade, observou-se uma maior prevalencia de BEN em criancas de 2 a 5anos e de 10 a 11 anos.

Evaluation of the reproducibility of two techniques used to determine and record centric relation in angle's class I patients

The centric relation is a mandibular position that determines a balance relation among the temporomandibular joints, the chew muscles and the occlusion. This position makes possible to the dentist to plan and to execute oral rehabilitation respecting the physiological principles of the stomatognathic system. The aim of this study was to investigate the reproducibility of centric relation records obtained using two techniques: Dawson’s Bilateral Manipulation and Gysi’s Gothic Arch Tracing. Twenty volunteers (14 females and 6 males) with no dental loss, presenting occlusal contacts according to those described in Angle’s I classification and without signs and symptoms of temporomandibular disorders were selected. All volunteers were submitted five times with a 1-week interval, always in the same schedule, to the Dawson’s Bilateral Manipulation and to the Gysi’s Gothic Arch Tracing with aid of an intraoral apparatus. The average standard error of each technique was calculated (Bilateral Manipulation 0.94 and Gothic Arch Tracing 0.27). Shapiro-Wilk test was applied and the results allowed application of Student’s t-test (sampling error of 5%). The techniques showed different degrees of variability. The Gysi’s Gothic Arch Tracing was found to be more accurate than the Bilateral Manipulation in reproducing the centric relation records.

Análise funcional da oclusão na dentadura decídua: avaliação dos movimentos mandibulares

Deciduous occlusion of 20 leukoderm children, 3.5 to 5.5 years old was analyzed from a functional viewpoint establishing maximal mandibular opening, maximal protrusion, and maximal lateral movements, in relation to sex, arch types, and movement records, using a millimeter ruler, gothic arch tracing and comparative microscope showing that the maximal opening capacity was 45.72 mm, without significant statistical differences among the variables. The mean values for the maximal protrusion were 8.34 mm for a millimeter ruler measuring and 7.25 mm for the gothic arch, with significant statistical differences at a level of 5% in the two evaluations, and in the interaction of evaluation/arch type, and evaluation/sex. The mean values for the maximal lateral movements were 8.11 mm for the right side and 8.15 mm for the left, with a millimeter ruler and by the gothic arch, 7.96 mm and 7.99mm with significant statistical differences at a level of 5% for the arch type. Thus the functional determinants of deciduous occlusion can be established serving as a base for maintenance, interception, morphological and functional restoration of the stomatognathic system when it is altered ensuring suitable development, including that of the permanent occlusion

Reestablishment of the condyle-fossa and maxillomandibular relationships using a flat occlusal plane splint and implant-supported denture: case report with a 2-year follow-up

Quando os componentes do sistema estomatognatico sofrem alteracoes na forma, estrutura e/ou funcao de uma das partes, tambem ocorrem modificacoes estruturais e fisiologicas para a absorcao ou compensacao das resultantes criadas. Assim, uma criteriosa reabilitacao deste tipo de paciente envolve procedimentos fundamentais, como: correta orientacao do plano oclusal, determinacao da dimensao vertical de oclusao adequada e a relacao maxilo-mandibular estavel e saudavel, sendo que a nao observacao destes aspectos pode levar ao fracasso da reabilitacao protetica. O objetivo do presente caso e relatar o planejamento pre-cirurgico e a reabilitacao protetica de um paciente edentulo com atrofia severa dos maxilares e sinais e sintomas de Desordens Temporomandibulares, que foi submetido a terapia com aparelhos oclusais planos e lisos para restabelecimento das relacoes condilo-fossa, maxilo-mandibular e da atividade muscular e, posterior reabilitacao oral com proteses totais fixas implantossuportadas,onde a determinacao da relacao maxilo-mandibular foi realizada pela tecnica do registro intraoral, com um periodo de proservacao de 24 meses.

Solução protética em paciente desdentado total em idade púbere

A indicacao de protese total na idade pubere e rara, porem se faz necessaria quando ocorre perda prematura de todos os dentes. E grande a preocupacao no que concerne a indicacao e confeccao de proteses totais para pacientes em fase de crescimento, visto que a protese e um fator limitante do crescimento dos maxilares. A proposta deste trabalho e descrever o caso clinico de um paciente com 13 anos de idade reabilitado com proteses totais com expansores localizados de acordo com os mameloes de crescimento. A proservacao protetica foi periodica para ajuste das proteses, permitindo o crescimento dos maxilares. Como resultado, as proteses foram essenciais no restabelecimento da funcao e da estetica, proporcionando ao paciente um convivio social saudavel.