RESUMEN
STATEMENT OF PROBLEM: How the translucency and color of ceramic restorations are affected by surface changes from the corrosive environment in the oral cavity and aging of materials is unclear. PURPOSE: The purpose of this in vitro study was to compare the impact of acidic exposure and aging on the color and translucency of monolithic zirconia and lithium disilicate ceramics. MATERIAL AND METHODS: Twenty computer-aided design and computer-aided manufacturing (CAD-CAM) monolithic zirconia specimens and 20 pressed lithium disilicate specimens were fabricated. Half of the specimens of each group were aged in an autoclave (7.5 hours, 134 °C, 0.2 MPa), and the rest were immersed in hydrochloric acid to simulate the acidic conditions in the oral cavity from gastric reflux. The color coordinates L∗, a∗, and b∗ were measured with an ultraviolet spectrophotometer before and after aging or acidic storage. The translucency parameters and contrast ratios were calculated, and the CIEDE2000 color difference formula was used to determine color differences before and after each treatment. ANOVA and ANCOVA test models were used for data analysis (α=.05), while differences of color parameters in respect to acceptability and perceptibility thresholds were evaluated with the 1-sample t test (α=.05). RESULTS: Lithium disilicate presented a significantly higher translucency parameter and lower contrast ratio at baseline compared with monolithic zirconia specimens (P<.001). Acidic storage significantly impacted all parameters compared with aging, especially for the lithium disilicate group. Color differences were above the acceptability ΔΕ00 threshold for lithium disilicate after acidic storage (P=.001) and below for monolithic zirconia after acidic storage (P=.003). CONCLUSIONS: The performance of lithium disilicate was slightly inferior compared with that of monolithic zirconia specimens, as they presented significant and clinically observable differences for the translucency parameter and ΔΕ00 after acidic storage and aging.
Asunto(s)
Porcelana Dental , Circonio , Cerámica , Color , Diseño Asistido por Computadora , Ensayo de Materiales , Propiedades de SuperficieRESUMEN
OBJECTIVE: Previous studies have indicated that dentists may be uncertain about the etiology, diagnosis, and effective management of dentine sensitivity/dentine hypersensitivity (DH).: The purpose of the present study was to evaluate the knowledge and understanding of Greece-based dental professionals in treating DH.: MATERIALS AND METHODS: A 26-item questionnaire was sent to a representative sample of Greek dentists. RESULTS: Two hundred thirty questionnaires were originally provided to the participants and of the 210 questionnaires that were returned, 191 questionnaires (90 M; 86 F; mean age 36.26 years [standard deviation: 11.34]) were included for analysis, a response rate of 83% was observed. 39.8% of dentists indicated that 1 in 10 of their patients experienced discomfort from DH with 76.4% of dentists indicating that their patients initiated the conversation on DH. In contrast, 44% of the dentists indicated that they initiated the relevant conversation. 34.9% of dentists indicated that the duration of discomfort lasted up to 3 weeks and 76.4% indicated that DH had an impact on their patients' quality of life. Incorrect tooth brushing was considered to be a major etiological factor (68.6%) with "air blast" (37.3%) and "probing" (15%) as the main methods for identification. 83.6% of dentists indicated that they were confident in recommending over-the-counter products for home use. CONCLUSION: The results of this study suggest that in terms of knowledge and understanding of DH, there is still confusion concerning some aspects of the diagnosis and management of the condition.