Efeito de agentes quimicos de limpeza na rugosidade superficial de resina acrilica e no acumulo de biofilme formado in situ

Orientadores : Altair Antoninha Del Bel Cury, Jaime Aparecido CuryDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaMestrad

Influência da solução de armazenagem na desmineralização do esmalte submetido à ciclagem de pH

Extracted human teeth are frequently used for research or educational purposes. Therefore, it is necessary to store them in disinfectant solutions that do not alter dental structures. Thus, this study evaluated the influence of storage solution on enamel demineralization. For that purpose, sixty samples were divided into the following groups: enamel stored in formaldehyde (F1), stored in thymol (T1), stored in formaldehyde and submitted to pH cycling (F2), stored in thymol and submitted to pH cycling (T2). All samples were evaluated by cross-sectional microhardness analysis and had their percentage of mineral volume versus micrometer (integrated area) determined. Differences between groups were found up to 30-µm depth from the enamel surface (p < 0.05), where samples from group T2 were more demineralized. It was concluded that the storage solution influenced the reaction of a dental substrate to a cariogenic challenge, suggesting that formaldehyde may increase enamel resistance to demineralization, when compared to demineralization occurring in enamel stored in thymol solution.Dentes humanos extraídos são freqüentemente utilizados para propósitos educacionais ou de pesquisa. Desta forma, é necessário o armazenamento dos mesmos em soluções desinfetantes que não alterem a estrutura dental. Para tanto, sessenta espécimes foram divididos nos seguintes grupos: esmalte armazenado em formol (F1), armazenado em timol (T1), armazenado em formol e submetido à ciclagem de pH (F2) e armazenado em timol e submetido à ciclagem de pH (T2), sendo avaliados por meio de análise de microdureza longitudinal e tiveram a porcentagem de volume mineral pro micrômetro determinada. Diferenças entre os grupos foram encontradas até a profundidade de 30µm da superfície do esmalte (

Effect of Colorant Solutions on the Color Stability of Provisional Prosthetic Materials

evaluate the color stability of acrylic and bis-acrylic resins after immersion in 3 staining solutions. Methods: Forty-eight samples (10 x 2 mm) of each provisional restorative material (Duralay, Dencrilay, Structur 2 and Protemp 4) were fabricated and distributed into four groups (n = 12): G1 distilled water (control group); G2 a cola flavored soft drink; G3 wine and G4 coffee. The specimens were immersed for seven days at 37°C in the solutions, which were changed every 24 hours. The color of all specimens was measured with a spectrophotometer (VITA Easyshade Advance) before (T0) and after immersion (T1), and the color changes (&#916;E) were calculated. Nonparametric Kruskal-Wallis tests were used, followed by Dunns test with a significance level of 5%. Results: For the acrylic resins (Duralay and Dencrilay), the largest color change values were obtained in group G4 coffee, whereas in the bis-acrylic resins (Protemp 4 and Structur 2), the largest color difference was observed in groups G3 wine and G4 coffee. The acrylic resins showed statistically significantly less color change than the bis-acrylic resins. Conclusions: The coffee and the wine promoted larger color changes in the provisional prosthetic materials tested in this study. The acrylic resins showed more color stability than the bis-acrylic resins

MOLDAGEM DIGITAL EM PRÓTESE DENTÁRIA DIGITAL IMPRESSIONS IN PROSTHODONTICS

O ato de moldar é uma prática comum nos consultórios, no entanto, como avanço na área odontológica e na busca pela modernização para promoverconforto ao paciente e agilidade nos tratamentos, surgiram no iníciodos anos 80, os modelos digitais. Com os avanços tecnológicos, osprocessos de moldagem e obtenção de modelo digital, como também,a produção da peça protética, são feitos por meio do sistema CAD/CAM(Computer Aided Design/ Computer Aided Manufacturing) otimizandoa qualidade e tempo das reabilitações orais. Assim, o objetivo desse trabalhofoi apresentar uma revisão de literatura sobre a moldagem digitalem prótese dentária, suas indicações, vantagens, desvantagens e principaissistemas digitais disponíveis. Foi realizada uma busca nos periódicosda CAPES, Pubmed e Bireme com as palavras-chaves “Prótese Dentária”,“Desenho Assistido Por Computador” e “Restauração Dentária Permanente”e utilizados artigos no período de 2005 a 2020. A moldagem digitalfornece resultados similares às técnicas de impressão convencionaise atende aos requisitos de precisão para o processo de transferência deinformações da boca do paciente para o laboratório de prótese dentária.Além disso, o conforto do paciente e a agilidade no tratamento sãoaspectos positivos que agregam valor à essa tecnologia. Existem muitossistemas digitais disponíveis atualmente na área odontológica, cabe aocirurgião-dentista e ao laboratório de prótese escolher qual se adequamelhor à sua rotina.The act of impression is a common practice in dentistry, however, withthe advances in the dental field and the search for modernization in orderto promote patient comfort and agility in treatments, digital modelsemerged in the early 1980s. With technological advances, the processes of impression and obtaining a digital model, as well as the fabrication ofprosthetic parts, are performed by CAD / CAM system, optimizing thequality and time of oral rehabilitations. Thus, the aim of this study wasto present a literature review on digital impression in dental prosthesis,its indications, advantages, disadvantages and main available digital systems.A search was conducted in CAPES, Pubmed and Bireme journalswith the keywords “Dental Prosthesis”, “Computer Assisted Design” and“Permanent Dental Restoration” and the period for the studies used wasfrom 2005 to 2020. Digital impressions provides similar results to conventionaltechniques and meets the precision requirements for the process oftransferring information from the patient’s mouth to the dental laboratory.In addition, patient comfort and agility in treatment are positive aspectsthat add value to this technology. There are many digital systems currentlyavailable in the dental field, it is up to the dentist and the prosthesis laboratoryto choose which one best suits your routine

Effect of different polishing methods on surface roughness of provisional prosthetic materials

Purpose: To evaluate the surface roughness of bis-acrylic and acrylic resins submitted to different methods of polishing. Materials and Methods: Fifty samples of each provisional restorative material (Structur 2, Protemp 4, Duralay, and Dencrilay) were fabricated (10 mm × 2 mm) and divided into five groups (n = 10): (1) positive control group – polyester strip; (2) negative control – unpolished; (3) abrasive tips (Exa-Technique-Edenta); (4) goat hair brush and diamond polishing paste; and (5) silicone tips (Enhance). Each material was mixed and polymerized according to manufacturer's instructions. The parameter evaluated was the arithmetic mean of the surface roughness (Ra) determined using the rugosimeter SJ 301 (Mitutoyo, Japan). The data were analyzed with two-way analysis of variance (post hoc Tukey's test) (P < 0.05). Results: The lowest surface roughness values (0,22–0,90 μm) were observed in the Group 4 – goat hair brush and diamond paste, while the highest values (1,17–1,44 μm) were found in the Group 5 – silicone tips (enhance), with statistically significant differences between them, except for Dencrilay acrylic resin. There was statistically significant difference between bis-acrylic and acrylic resins in the Groups 1, 2, and 4. Conclusions: Within the limitations of this study, it was concluded that the most effective polishing system was the goat hair brush with diamond paste for both bis-acrylic and acrylic resins. The bis-acrylic resins exhibited significantly smoother surfaces than the acrylic resins

PROTOCOLOS PARA REMOÇÃO DE RETENTORES INTRARRADICULARES DE FIBRA DE VIDRO: UMA REVISÃO CRÍTICA

Objetivo: investigar na literatura especializada os protocolos para a remoção de retentores intrarradiculares de pino de fibra de vidro. Nestes estudos as va- riáveis pontas diamantadas, brocas de largo e peso bem como kits específicos para remoção de pinos foram estudados isoladamente e associados ao ultras- som com insertos de diversas formas, com e sem cobertura diamantada. Em alguns casos as remoções foram facilitadas com a utilização do microscópio operatório. Consideraçõesfinais: o uso de ultrassom é um método valioso para a remoção de pinos de fibra de vidro, aumentando a sua eficiência quando associado à magnificação do microscópio. No entanto, novas investigações envolvendo a combinação dos procedimentos da vibração ultrassônica, bro- cas e kits de brocas são necessários, visando aumentar a previsibilidade e a eficácia dessa técnica

ADAPTAÇÃO MARGINAL DE COROAS CAD-CAM DE PORCELANA FELDSPÁTICA COM PREPARO CONVENCIONAL E ULTRAFINO

Objetivo: avaliar a influência da espessura do preparo na adaptação marginal de coroas de porcelana feldspática fabricadas pela tecnologia CAD/CAM e identificar a(s) face(s) que apresenta(m) maior discrepância marginal em cada preparo. Metodologia: Dois molares inferiores humanos foram preparados para coroa total: preparo convencional (PC) – chanfro: 1,0 mm, redução oclusal: 2 mm e axial: 1,5 mm; preparo ultrafino (PUF) – chanfro arredondado: 0,5 mm, redução oclusal e axial: 0,7 mm. Os preparos foram escaneados com escâner intraoral e os dados processados no software Cerec InLab foram transmitidos à fresadora. Sobre os dois tipos de preparo foram confeccionadas coroas de porcelana feldspática (Cerec Blocs) (n=10). As coroas foram adaptadas ao dente preparado e analisadas em lupa estereoscópica com aumento de 45x. As imagens obtidas foram transferidas para o programa Corel Draw para leitura da discrepância marginal. O teste estatístico utilizado para avaliar os tipos de preparo foi t de Student e para as faces foram ANOVA e Bonferroni (p&lt;0.05). Resultados: Os menores valores de discrepância marginal foram encontrados no grupo PC (73,25 ± 18,19) que diferiu estatisticamente do grupo PUF (110,40 ± 28,64). As faces mesiais de ambos os grupos apresentaram maiores valores de discrepância marginal (PC=132,01 ± 50,93 e PUF=173,01 ± 73,63), respectivamente, com diferença estatisticamente significante em relação às demais faces. Conclusão: As coroas de porcelana feldspática com PC apresentaram melhor adaptação marginal comparadas às coroas com PUF. As faces dentárias apresentaram valores de discrepância marginal dentro do parâmetro utilizado (≤120 μm), exceto a face mesial, em ambos os preparos

Evaluation of surface characteristics of Ti-6Al-4V and Tilite alloys used for implant abutments

The aim of this study was to evaluate surface free energy (SFE), surface roughness (SR) and surface hardness (SH) of two commercially available materials for fabricating dental implant abutments. In addition, the specimens were investigated by scanning electron microscopy (SEM) to determine the surface morphology. Twenty five discs (5 x 2 mm) of Ti-6Al-4V and Tilite (Ni-Cr-Ti) alloys were used in this study. Surface free energy was determined by the contact angle formed between a drop of distilled, deionized water and the surface of the specimen of each material. The surface roughness was measured with a mechanical profilometer and the surface hardness was evaluated by means of the Vickers hardness micro indentation test. SFE, SR and SH data were analyzed using one-way ANOVA (p < 0.05). Statistical differences (p < 0.05) were found between Ti-6Al-4V (36.2 erg.cm-2; 0.2 µm) and Tilite (30.9 erg.cm-2; 0.16 µm) for SFE and SR. However, the differences between the surface hardness values of Ti-6Al-4V (325.0 kg/mm²) and Tilite (324.3 kg/mm²) were not statistically significant (p > 0.05). Evaluations by SEM revealed different surface morphology. Within the limits of this study, it can be concluded that the Ti-6Al-4V and Tilite alloys showed differences in surface properties, except for surface hardness, suggesting that both alloys may be considered appropriate for producing abutments. Further studies are, however, necessary to elucidate the biological responses to implant abutments made with these alloys