Abstract
OBJECTIVE: This in vitro study evaluated the retention of copings cemented with a provisional cement and a permanent cement on wide-platform short abutments with different surface texture.METHODS: Two wide-platform abutments (height 4.0 mm) with machined (original) or modified surface (air-blasted with 50-µm aluminum oxide) were connected to two implant replicas under torque of 35 N.cm. Ten copings were cast in Cr-Co alloy from calcinable cylinders. Each coping was luted on the abutment under an axial force of 5 kg for 10 min, and the specimen was stored in a humid environment at 37°C for 20 h. After mechanical cycling simulating masticatory fatigue for 7 days (5754 cycles, 60 cycles/min, 200 N, 37°C), the specimens were subjected to a uniaxial tensile test at 0.5 cm/min, and the maximum retention strength (N) was recorded. After testing, the surfaces were cleaned, and the procedures were repeated for each coping in the experimental group. Data were analyzed by Student t test for paired samples. RESULTS: For the temporary cement, the mean retention (SD) was 36.1 (10.7) N for the machined surface and 49.6 (2.7) N for the blasted surface (P=0.004) (37% increase). For the zinc phosphate cement, the values were 292.0 (89.8) N and 440.6 (48.1) N, (P<0.001) (42% increase).CONCLUSION: The results suggest that the air-blasting of short and wide abutments increases the retention of the cast coping cemented with temporary or permanent cement.
Highlights
Cement-retained single crowns, splinted crowns, and cantilever-fixed partial dentures seem to perform better than screw-retained restorations in the long term [1]
The results suggest that the air-blasting of short and wide abutments increases the retention of the cast coping cemented with temporary or permanent cement
The modified-surface abutment was again blasted with aluminum oxide particles before each cementation procedure to restore the experimental surface treatment
Summary
Cement-retained single crowns, splinted crowns, and cantilever-fixed partial dentures seem to perform better than screw-retained restorations in the long term [1]. Many factors related to the abutment (degree of taper, surface area, height, surface roughness), the crown (inner surface, properties of metal alloy) and the luting agent (type, composition, thickness) can affect the retention of cemented restorations [2, 3]. The height and width of the abutment are geometric factors to determine the surface area to be luted, which are potentially related to the retention of crowns. A decrease in the taper degree of the abutment seem to increase more the retention strength of implant-supported crowns than the increase in height of the abutment [4, 5]. Sometimes it is difficult to optimize the taper degree of prefabricated abutments, the height and width of the abutment due to anatomical limitations. In some clinical situations, such as multi-unit angled abutments for fixed prostheses, an increase of taper degree may be necessary to allow a proper axis of insertion of the partial or full-arch restoration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
