A preliminary evaluation into the performance of posterior resin bonded cast metal restorations (adhesive onlays).

Posterior resin bonded cast metal restorations (adhesive onlays) were used in a variety of clinical scenarios including: management of tooth wear and cracked tooth, as retainers for fixed bridge work, for correction of the occlusal plane and in providing cuspal coverage following endodontic treatment. The mean length in service for the examined onlays was 42 months, with a range of 9-75 months. Two restorations in two patients failed resulting in an overall success of 94%. Patient satisfaction was high at 95%. Such restorations seem to be a viable option for managing a number of clinical scenarios.

Surface properties of dental nanocomposites after finishing with rigid rotary instruments.

This study evaluated the surface characteristics of three nanoparticle resin composites (Z350, Heritage 7 Nanohybrid, and Ice) using profilometry and scanning electronic microscopy (SEM) after subjecting them to sequential finishing procedures using rigid rotary instruments. Fifteen 8 mm × 8 mm × 2 mm specimens were fabricated for each tested composite and subjected to one of the following finishing regimens: finishing with green stones followed by white stones, finishing with 45-µm diamond followed by 15-µm diamond, finishing with a 12-fluted carbide followed by a 20-fluted carbide. After finishing, the surfaces were subjected to profilometric testing. Eight parallel tracings were used to scan the finished surface of each specimen. For each recorded profile, the average roughness (Ra) and extreme value descriptor (Rmax) were recorded. On completion of the profilometric testing, two specimens from each group were randomly selected for qualitative assessment by SEM. Profilometric data was analyzed using a one-way analysis of variance and post hoc Scheffe tests. The results demonstrated that the three control groups of the tested nanocomposites behaved as a coherent group with respect to surface roughness. With the exception of the nanohybrid Heritage 7 finished with the carbide instruments, all composites showed an increase in surface roughness. The Z350 and Ice finished with the carbide finishing instruments showed no statistically significant increase in Ra, but both of these composites showed significantly rougher surfaces when finished with diamonds compared with controls. The nanohybrids Ice and Heritage 7 demonstrated significantly higher roughness in terms of Rmax when finished with stones. The SEM correlated well with roughness measurements. The conclusion may be drawn that diamonds and stones produce unacceptable surfaces in terms of roughness on the tested nanocomposites whereas finishing carbides produce acceptable surfaces.

Surface Properties of Dental Nanocomposites After Finishing With Rigid Rotary Instruments

This study evaluated the surface characteristics of three nanoparticle resin composites (Z350, Heritage 7 Nanohybrid, and Ice) using profilometry and scanning electronic microscopy (SEM) after subjecting them to sequential finishing procedures using rigid rotary instruments. Fifteen 8 mm·8mm·2mmspecimens were fabricated for each tested composite and subjected to one of the following finishing regimens: finishing with green stones followed by white stones, finishing with 45-lm diamond followed by 15-lm diamond, finishing with a 12-fluted carbide followed by a 20-fluted carbide. After finishing, the surfaces were subjected to profilometric testing. Eight parallel tracings were used to scan the finished surface of each specimen. For each recorded profile, the average roughness (Ra ) and extreme value descriptor (Rmax ) were recorded. On completion of the profilometric testing, two specimens from each group were randomly selected for qualitative assessment by SEM. Profilometric data was analyzed using aone-way analysis of variance and post hoc Scheffe tests. The results demonstrated that the three control groups of the tested nanocomposites behaved as a coherent group with respect to surface roughness. With the exception of the nanohybrid Heritage 7 finished with the carbide instruments, all composites showed an increase in surface roughness. The Z350 and Ice finished with the carbide finishing instruments showed no statistically significant increase in Ra , but both of these composites showed significantly rougher surfaces when finished with diamonds compared with controls. The nanohybrids Ice and Heritage 7 demonstrated significantly higher roughness in terms of Rmax when finished with stones. The SEM correlated well with roughness measurements. The conclusion may be drawn that diamonds and stones produce unacceptable surfaces in terms of roughness on the tested nanocomposites whereas finishing carbides produce acceptable surfaces.