Transmission of light in the visible spectrum (400-700 nm) and blue spectrum (360-540 nm) through CAD/CAM polymers.

OBJECTIVES: CAD/CAM-fabricated long-term temporary restorations from high-density polymers can be applied for a wide range of indications. Milled from monolithic, mono-colored polymer blocks, the translucency of the material plays an important role for an esthetically acceptable result. The aim of this study was to compare the transmittance through visible light and blue light of CAD CAM polymers to a glass-ceramic material of the same color. MATERIALS AND METHODS: Ambarino High-Class (AM), Telio-CAD (TC), Zenotec PMMA (ZT), Cercon base PMMA (CB), CAD Temp (CT), Artbloc Temp (AT), Polycon ae (PS), New Outline CAD (NC), QUATTRO DISK Eco PMMA (GQ), Lava Ultimate (LU), and Paradigm MZ 100 (PA) were employed in this study using the feldspathic glass-ceramic Vita Mark II (MK) as control group. Using a spectrophotometer, the overall light transmittance was measured for each material (n = 40) and was calculated as the integration (t c (λ) dλ [10-5]) of all t c values for the wavelengths of blue light (360-540 nm). Results were compared to previous data of the authors for visible light (400 to 700 nm). RESULTS: Wilcoxon test showed significant differences between the light transmittance of visible and blue light for all materials. CONCLUSION: CAD/CAM polymers showed different translucency for blue and visible light. This means clinicians may not conclude from the visible translucency of a material to its permeability for blue light. This influences considerations regarding light curing. CLINICAL RELEVANCE: CAD/CAM polymers need to be luted adhesively; therefore, clinicians should be aware about the amount of blue light passing through a restoration.

HIP zirconia fixed partial dentures--clinical results after 3 years of clinical service.

OBJECTIVE: To evaluate prospectively the clinical performance of 3- to 6-unit zirconia fixed partial dentures (FPDs) after more than 3 years of clinical service. METHOD AND MATERIALS: Since August 2002, 22 conventional all-ceramic FPDs have been inserted in 18 patients. Nineteen of the FPDs were placed with a resin-reinforced glass-ionomer cement. The frameworks were manufactured by a universal CAD/CAM production system, milling the zirconia out of the densely sintered stage. The frameworks were designed as 3-unit (14), 4-unit (3), 5-unit (2), and 6-unit FPDs (3) for the anterior and posterior regions. A new synthetic sintering glass-ceramic was employed as the veneering material. In the follow-up examinations at baseline, 6, 12, 24, and 36 months, 21 FPDs were inspected predominantly for framework fractures and chipping of the veneering material. Besides these parameters, periodontal status, sensitivity of the abutment teeth, esthetic outcome, as well as the incidence of secondary caries, were evaluated. RESULTS: After a mean clinical observation of over 39 months, no framework fracture occurred. However, chipping of the veneering material was reported in 2 cases. CONCLUSION: All-ceramic FPDs based on zirconia frameworks exhibited satisfactory clinical performance.