Influencia dos materiais de moldagem e das tecnicas de transferencia em implantes, na precisão dimensional linear dos modelos de gesso

Orientadores: Saide Sarckis Domitti, Simonides ConsaniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O propósito deste estudo foi verificar a alteração dimensional linear em modelos de gesso à partir de reproduções de uma matriz metálica com 4 transferentes para implantes. Os modelos foram confeccionados utilizando-se três materiais de moldagem e três técnicas de moldagem de transferência. Os materiais de moldagem utilizados foram: silicona por adição(Express); silicona por condensação(Optosil-Xantopren) e poliéter (Impregum F). As técnicas de moldagem de transferência adotadas foram: transferente com "coping" metálico com resina "Duralay" esculpida em forma quadrada; técnica com o transferente e "coping" metálico unidos com resma "Duralay"; e técnica com transferentes cónicos. Após confeccionada a matriz metálica, representando uma maxila desdentada total, foram fixados quatro implantes em posições simétricas, sendo dois em cada semi-arco, utilizando quatro transferentes cilíndricos com faces oclusais lisas e polidas, e ponto central geométrico bem definido, os quais serviram para a realização das medidas originais entre os transferentes rosqueados na matriz metálica. Os ensaios foram realizados de acordo com a especificação na 19 da A.D.A.38 e Revisão da I.S.O. 4823/198439. Foram utilizadas 45 moldeiras individuais para a realização das moldagens. Para os ensaios de alteração dimensional linear foram confeccionados cinco moldes para cada material de moldagem com uma das técnicas de transferência. Os moldes foram removidos da matriz 3 minutos além do tempo recomendado pelos fabricantes e imediatamente preenchidos com gesso pedra mellhorado, sobre vibração. As leituras dos valores das alterações dimensionais lineares foram realizadas num microscópio comparador CARL ZEISS (Alemanha), nas medições com os transferentes cilíndricos na matriz metálica. Os resultados obtidos foram submetidos a analise de variância e ao teste de Tukey, indicaram que as três técnicas de moldagem de transferência não exerceram influência sobre a alteração dimensional, assim como não houve diferença estatisticamente significativa (p0,05) on the dimensional changing of the casts, obted in molds of silicone by addition (Express) and the polyether (Impregum F); except to the silicone by condensation (Optosil-Xantopren) in a few situationsDoutoradoProteseDoutor em Clínica Odontológic

New image analysis of large food particles can discriminate experimentally suppressed mastication

Objective parameters that could provide a basis for food texture selection for elderly or dysphagic patients have not been established. We, therefore, aimed to develop a precise method of measuring large particles (>2 mm in diameter) in a bolus and an analytical method to provide a scientific rationale for food selection under masticatory dysfunction conditions. We developed a new illumination system to evaluate the ability of twenty female participants (mean age, 23·4 ± 4·3 years) to masticate carrots, peanuts and beef with full, half and one quarter of the number of masticatory strokes. We also evaluated mastication under suppressed force, regulated by 20% electromyographic of the masseter muscle. The intercept and inclination of the regression line for the distribution of large particles were adopted as coefficients for the discrimination of masticatory efficiency. Single set of coefficient thresholds of 0·10 for the intercept and 1·62 for the inclination showed excellent discrimination of masticatory conditions for all three test foods with high specificity and sensitivity. These results suggested that our method of analysing the distribution of particles >2 mm in diameter might provide the basis for the appropriate selection of food texture for masticatory dysfunction patients from the standpoint of comminution

Comparative study of the relation between two methods of mensuration of the angle of condylar sagital pathway, using two recording materials

A morfologia oclusal em qualquer procedimento realizado na boca deve apresentar equilíbrio com os movimentos mandibulares. O correto ajuste dos guias condilares no articulador possibilita que uma reabilitação oclusal seja facilitada e obtenha sucesso. Com a finalidade de verificar a precisão da individualização da inclinação da trajetória sagital condílica em articulador semi-ajustável, estudaram-se dois materiais de registro intra-oral: cera associada a resina e silicone polimerizável por adição. A mensuração dos ângulos obtidos foi realizada através do aparelho Buhnergraph e diretamente nas guias condilares do articulador. Diante dos resultados encontrados, conclui-se que não há diferença estatisticamente significativa entre os materiais, independentemente do método utilizado para a leitura dos ângulos da inclinação condilar. ______________________________________________________________________________________ ABSTRACTThe occlusal morphology in any procedure made in mouth must keep in balance with the mandibular movements. The right adjustment of the condylar guidances in the articulator makes possible for an occlusal rehabilitation to be easy and well succeeded. In order to check out the individualization accuracy of the condylar sagital pathway inclination in semi-adjustable articulator, there were studied two materials to intraoral impression: wax associated with resin and addition silicone. The measurement of the angle obtained was made by the Buhnergraph device and directly on the condylar guidance of the articulator. With the found results, we may conclude that there is no significant statistical difference between the materials, no matter which method is used to determine the angles of condylar inclination

Patients’ profile attack for laryngeal cancer attended in oral cancer center – UNESP

Um estudo foi realizado no Centro de Oncologia Bucal da Universidade Estadual Paulista, Campus de Araçatuba. Entre 88 casos de câncer atendidos no Centro de tratamento oncológico entre 1991 e 2003, 80 casos de câncer de laringe foram identificados em homens. Sexo, idade, uso de tabaco e álcool, realização de cirurgia e tratamentos oferecidos após a cirurgia foram dados obtidos de pacientes com um questionário padrão. O maior número de casos de câncer de laringe ocorreu em região glótica e necessitou de intervenção cirúrgica (laringectomia parcial ou total). A freqüência de câncer de laringe foi mais alta em fumantes e foi mais comum em idade entre 50 e 69 anos. O tratamento fonoaudiológico e a utilização de prótese estética ainda estão restritos a menor porcentagem dos pacientes. ____________________________________________________________________________________ ABSTRACTA study was conducted in Oral Cancer Center, São Paulo State University – UNESP, Araçatuba Campus. Among 88 cancer cases seen at an oncology treatment center between 1991 and 2003, 80 laryngeal cancer cases were identified among men. Gender, age, tobacco and alcohol use, necessity of surgery and treatment proposed after surgery were data obtained from patients with a standardized questionnaire. The highest number laryngeal cancer cases occurred in glottic region and were necessary surgery intervention (partial or total laryngectomy). The frequency of laryngeal cancer was higher in tobacco smoking, and was more common in age among 50 and 69 years. The speech therapy and the use of esthetic prosthesis are still restrict to a minor percentage of the patients

Assessment of the flexural strength of two heat-curing acrylic resins for artificial eyes

Prosthetic eyes are artificial substitutes for the eyeball, made of heat-curing acrylic resin, serving to improve the esthetic appearance of the mutilated patient and his/her inclusion in society. The aim of this study was to assess the flexural strength of two heat-curing acrylic resins used for manufacturing prosthetic eyes. Thirty-six specimens measuring 64 x 10 x 3.3 mm were obtained and divided into four groups: acrylic resin for artificial sclera N1(Artigos Odontológicos Clássico, São Paulo, SP, Brazil), heat-cure water technique (GI) and microwave-cured (GII); colorless acrylic resin for prosthetic eyes (Artigos Odontológicos Clássico, São Paulo, SP, Brazil), heat-cure water technique (GIII) and microwave-cured (GIV). Mechanical tests using three point loads were performed in a test machine (EMIC, São José dos Pinhais, PR, Brazil). The analysis of variance and the Tukey test were used to identify significant differences (p < 0.01). Groups GII and GIV presented, respectively, the highest (98.70 ± 11.90 MPa) and lowest means (71.07 ± 8.93 MPa), with a statistically significant difference. The cure method used for the prosthetic eye resins did not interfere in their flexural strength. It was concluded that all the resins assessed presented sufficient flexural strength values to be recommended for the manufacture of prosthetic eyes

Color alteration of the paint used for iris painting in ocular prostheses

The purpose of this study was to assess color alteration of the paints used for iris painting in artificial eyes. Five disks of heat cured acrylic resin were confectioned by microwave energy for each paint analyzed, in a total of 40 specimens. Each specimen consisted of a colorless acrylic resin disk and another of equal size, of scleral white colored acrylic resin, with the painting interposed between the two disks. The specimens were submitted to an accelerated aging process in a chamber under ultraviolet radiation for 1,008 hours. To assess color variation, a reflective spectrophotometer was used. The results were statistically analyzed by ANOVA and the Tukey test (p < 0.05). All the paints underwent chromatic alteration. The oil paint presented the highest resistance to accelerated aging

Analysis of masticatory cycle efficiency in patients with old and new dentures

Background: The loss of vertical dimension of occlusion, wear of acrylic teeth and the maladaptation of old complete dentures on the tissues can influence chewing of edentulous individuals. The aim of the present study was to analyze the masticatory efficiency in patients with old complete dentures and after 6 months with new complete dentures. Methods: Twenty four edentulous patients between the ages of 65 to 80 years, with old complete dentures (maxillary and mandibular) and without temporomandibular dysfunction were selected. The patients included had decreased vertical dimension of occlusion and deficient dental occlusion. Each patient received artificial food fragments weighing 3 grams and chewed for 35 cycles. The food particles were expelled in granulometric meshes with openings of 2.0, 1.08, 0.42 and 0.20 mm. The analysis occurred with old complete dentures and after 6 months with new complete dentures. Results: Analysis of variance (ANOVA) and Tukey test with 5% significance were performed. After 6 months of wearing new complete dentures, the masticatory efficiency was significantly increased with 0.42 mm mesh, whereas the other meshes did not show increased masticatory efficiency. Conclusion: In general, there was no improvement in the masticatory efficiency of the edentulous individuals after 6 months with new complete dentures

Evaluation of the color stability of two techniquesfor reproducing artificial irides after microwave polymerization

The use of ocular prostheses for ophthalmic patients aims to rebuild facial aesthetics and provide an artificial substitute to the visual organ. Natural intemperate conditions promote discoloration of artificial irides and many studies have attempted to produce irides with greater chromatic paint durability using different paint materials. OBJECTIVES: The present study evaluated the color stability of artificial irides obtained with two techniques (oil painting and digital image) and submitted to microwave polymerization. MATERIAL AND METHODS: Forty samples were fabricated simulating ocular prostheses. each sample was constituted by one disc of acrylic resin N1 and one disc of colorless acrylic resin with the iris interposed between the discs. The irides in brown and blue color were obtained by oil painting or digital image. The color stability was determined by a reflection spectrophotometer and measurements were taken before and after microwave polymerization. Statistical analysis of the techniques for reproducing artificial irides was performed by applying the normal data distribution test followed by 2-way ANOVA and Tukey HSD test (&#945;=.05). RESULTS: Chromatic alterations occurred in all specimens and statistically significant differences were observed between the oil-painted samples and those obtained by digital imaging. There was no statistical difference between the brown and blue colors. Independently of technique, all samples suffered color alterations after microwave polymerization. CONCLUSION: The digital imaging technique for reproducing irides presented better color stability after microwave polymerization

The influence of chemical disinfection of two silicone types on dimensional changes and on the maintenance of details of plaster casts

A possibilidade de haver infecção cruzada através de moldes tornou necessária a desinfecção de materiais de moldagem, previamente ao vazamento de gesso. O propósito deste estudo foi avaliar a influência da desinfecção química com solução à base de glutaraldeído a 2% em modelos obtidos por duas marcas de gesso especial, por aspersão de dois tipos de material elastomérico de impressão, durante 15 minutos, analisados segundo testes de alteração dimensional linear e manutenção de detalhes. Os resultados, após análise estatística pelo teste de Tukey, mostraram haver alteração dimensional nos modelos de gesso obtidos a partir de materiais elastoméricos diferentes, independentemente da desinfecção química. _______________________________________________________________________________________ ABSTRACTThe possibility of cross-contamination by handling moulding impressions has made necessary the disinfection of moulding materials, before the plaster casting. The purpose of this study was to analyse the influence of chemical disinfection with a 2% glutaraldehyde-based solution, on plaster casts obtained with two brands of dental gypsum, by sprinkling it, for 15 minutes, on two types of elastomeric impression materials, in order to detect dimensional changes and maintenance of details. After the statistical analysis by the Tukey’s Test, the results indicated that the occurrence of dimensional changes in plaster casts obtained from different elastomeric impression materials, does not depend on chemical disinfection