Resumo: Este estudo avaliou o efeito da desinfecção por micro-ondas sobre o desempenho clínico e a quantificação de micro-organismos de um reembasador rígido em diferentes intervalos de tempo. Foram selecionados 40 pacientes de ambos os sexos com idade entre 30 e 75 anos, utilizando prótese total superior com necessidade de reembasamento. Essas próteses foram reembasadas com o material Tokuyama Rebase II. Logo após o reembasamento, foi avaliado o escoamento e a lisura do material, classificando-os em satisfatório ou insatisfatório. Em seguida, a amostra foi separada em dois grupos: grupo GC (controle) - os pacientes higienizaram sua prótese três vezes ao dia por meio de escovação com sabão de coco. Além disso, a prótese foi retirada durante a noite, ficando imersa em água e grupo GD (desinfecção por micro-ondas) - nesse grupo, além da escovação com escova dental macia e sabão de coco, foi realizada a desinfecção da prótese por micro-ondas uma vez por semana utilizando a potência de 650W e o tempo de 3 minutos. No período noturno, a prótese também foi imersa em água. O material reembasador foi avaliado por dois profissionais treinados trabalhando separadamente após 7 dias, 15 dias, 1 mês, 3 meses, 6 meses, 9 meses e 1 ano. Foram analisadas as seguintes características: estabilidade de cor, brilho, descoloração ou manchamento, irritação dos tecidos orais, separação ou fratura do material e rugosidade superficial. Além disso, foi realizada a quantificação de micro-organismos presentes na superfície interna da prótese em todos os períodos experimentais. Os dados obtidos foram analisados por análise de variância e pelos testes de Tukey e Friedman, ao nível de significância de 5%. O material apresentou lisura e escoamento satisfatórios em todas as análises após o reembasamento. As próteses reembasadas submetidas à desinfecção... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study evaluated the effect of disinfection method on the clinical performance and quantification of microbial of a hard chairside reline resin after 1-year service period. Forty adult patients aged between 30 and 75 years, who required denture reline treatment, participated in this study. Tokuyama Rebase II was used to reline complete maxillary dentures. Immediately after the reline, assessment of the flow and smoothness was rated by the clinician as satisfactory and unsatisfactory. The edentulous subjects were randomly divided into 2 groups (n=20) and dentures were cleansed according to two methods: CG (control group)- brushing with coconut soap and soft toothbrush; DG (disinfection group)-brushing according to previous methods and microwave disinfection once a week for 3 min at 650W. Furthermore, all dentures were immersed in water at night. Evaluations were conducted by two examiners working separately. Color stability, gloss, staining or material discoloration, irritation to oral tissue, detachment or frature of material and surface roughness were assessed at 7 and 15 days, 1, 3, 6 and 9 months and 1 year post-placement. Quantitative microbial cultures were taken from the tissue side of each maxillary denture at all experimental periods. The data were analyzed by ANOVA and Friedman and Tukey tests. A 95% confindence level was used. Flow and smoothness of the material during relining were considered to be good or satisfactory in all the cases. Values color alterations of DG were significantly lower than those of CG (P<0.05). Color change observed after 15 days are greater than values obtained at 7 days recall (P<0.05). All color changes observed for the CG were considered noticeable (between 1.5 and 3.0 NBS). In disinfection group, color change was slight (between 0.5 and 1.5 NBS). There were statistically significant... (Complete abstract click electronic access below) / Orientador: Eunice Teresinha Giampaolo / Coorientador: Carlos Eduardo Vergani / Banca: Ana Cláudia Pavarina / Banca: Ana Lúcia Machado / Banca: Helena de Freitas Oliveira Paranhos / Banca: Marcelo Ferraz Mesquita / Doutor

OBJECTIVES: Evaluate the mechanical properties of commercial digital denture base materials. Materials: The materials used were Lucitone 199 denture base disc (Dentsply Sirona), AvaDent denture base puck (AvaDent), KeyMill denture base disc (Keystone), Lucitone digital print denture base resin (Dentsply Sirona), Formlabs denture base resin (Formlabs), and Dentca denture base resin II (Dentca). METHODS: For each material, 60 bar-shaped specimens were prepared for flexural testing, which were divided into 5 groups including control, fatigue, thermocycling, and repairing using 2 types of materials. 24 square-shaped specimens were included in the bond testing, bonded to tooth and composite resin. Additionally, 48 square-shaped specimens were fabricated for the color stability testing, against UV light and staining and washing solutions. The flexural strength and modulus were calculated through 3-point bend test. Bond strength was determined using shear bond test. Color coordinates were recorded in the CIE L*a*b* system using an X-Rite Ci7600 spectrophotometer. Color differences relative to the baseline (∆E^*) were obtained. Data were analyzed using one-way ANOVA followed by Tukey’s HSD test (α=0.05). RESULTS: Milled materials showed higher flexural strength than printed materials. Fatigue and thermocycling led to a decrease in the flexural strength of both group materials. Repaired groups showed flexural strength of about 30.67% and 32.80% of its original strength, in milled and printed materials respectively. However, the flexural strength of the printed materials was affected by the type of the repair material, composite resin gave higher values compared with acrylic. Printed materials exhibited superior bond strength to tooth and composite resin than milled materials. The color change under UV light was clinically acceptable. The color change after immersion in staining and washing solutions in milled groups was less noticeable than in the printed group. Thermocycling treatment made the color change more noticeable in both milled and printed groups. CONCLUSION: Milled denture materials exhibited higher flexural properties than printed denture materials. Printed materials exhibited higher shear bond to tooth and composite resin. The color stability of milled materials with staining and washing solutions treatment was better than the printed groups, whereas the color stability of milled and printed materials exposed to UV light was clinically acceptable. / 2023-08-03T00:00:00Z

OBJECTIVE: To assess the effect of denture cleansers on the mechanical and optical properties such as color stability, surface hardness, surface roughness, and flexural strength of the 3D printed denture acrylics in comparison to heat polymerized denture acrylics. MATERIALS AND METHODS: A total of 216 disc specimens (12 mm × 2mm) were made from Lucitone Digital Print, DENTCA Denture Base II, Formlabs denture resin, and Lucitone 199. Each type of acrylic was divided into four sub-groups, Efferdent, Polident, dish soap and control group in water. Specimens of each material were exposed to a total of 28 cycles of immersion in denture cleanser, while being stored in water in an incubator at 37°C in between cycles to test for color stability, surface roughness, microhardness and biaxial flexural strength. Baseline values were obtained for color, hardness, surface roughness, and biaxial flexural strength using a CIE L*a*b* color space by spectrophotometer, Vickers microhardness in hardness tester, line Ra by profilometer, and ball-on-three-ball fixture with universal testing machine respectively. Color, surface roughness, and surface hardness values were obtained at the 8th, 16th, and 28th cycles in order to compare color stability along with changes in surface roughness and surface hardness. Biaxial flexural strength values were performed for specimens at the 28th cycle as a destructive test to compare values of treated and untreated specimens. SEM analysis was performed to assess fracture behavior and microstructural changes. The differences between the tested materials and the treatment effects were statistically analyzed using the Tukey HSD test (a=0.05) and MANOVA test (a=0.05) RESULTS: The greatest significant change in color was seen in Lucitone 199 specimens (P value <0.0001) when exposed to dish soap. Lucitone 199 and Lucitone Digital Print had the significantly lowest microhardness values (P value< 0.0001) after exposure to treatments, especially dish soap. Surface roughness was significantly higher for all 3D specimens initially (P value <0.001), however with exposure to Efferdent and Polident, Lucitone 199 specimens had the greatest significant increase in surface roughness. The surface roughness of 3D printed specimens did not significantly increase with exposure to treatments. The biaxial flexural strength of all materials decreased significantly with the exposure to all treatments (P value< 0.0001). Overall, Lucitone 199 had the lowest flexural strength in both treatment and control groups compared to all the 3D printed materials. Formlabs was significantly affected by exposure to treatments,and had the greatest decrease in biaxial flexural strength (P value <0.0001). CONCLUSION: Within the limitations of this study, we can conclude that 3D printed materials in this study are more color stable that the heat-polymerized Lucitone 199. In regards to microhardness, 3D printed materials except for Lucitone Digital Print have higher microhardness values than heat-polymerized materials. Although Lucitone 199 had a smoother surface as prepared, the 3D printed materials in this study maintained their roughness values throughout the study, whereas Lucitone 199 showed a significant increase in roughness. The properties of 3D printed materials show a promising future for their use in treating edentulous patients. Although there are limitations to this study, it is safe to say that denture cleansers are safe to use with 3D printed dentures as long as the manufacturer’s instructions are correctly followed.

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Thesis (M.S.)--University of Michigan, Ann Arbor, 1978. / Typescript (photocopy). Includes bibliographical references (leaves 141-148). Also issued in print.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1976. / Typescript (photocopy). Includes bibliographical references (leaves 76-80). Also issued in print.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1973. / Typescript (photocopy). Includes bibliographical references (leaves 71-72). Also issued in print.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1974. / Typescript (photocopy). Includes bibliographical references (leaves 59-62). Also issued in print.