Marginal Fit of a Nobel Biocare Implant Temporization System

Objective: Marginal fit of the Nobel Biocare (NB) Immediate Temporary Abutment (ITA) was assessed with and without the plastic sleeve and in a simulated, deep, gingival cuff situation. Method: NB Select Replace Tapered Groovy 4.3 mm X 10 mm root form implant (SRTG43) was placed into a training bone block. The ITA was then screwed into the implant. Polycarbonate crown shells (PCS) were filled with self-curing polymethyl methacrylate (PMMA) and applied to the ITA with (SY) and without the sleeve (SN) and allowed to cure. After curing, the provisional crowns were removed and excess PMMA was trimmed using a custom jig made with another ITA and an SRTG43 implant analog under 2.6X magnification. NB SRTG43 was custom mounted in a typodont to replace tooth #8 with a polyvinyl siloxane custom gingival cuff ~ 8 mm deep and then fitted with an ITA. PCS were filled with PMMA and applied to the ITA, allowed to cure and the provisional crowns were removed. One group was corrected (CY) by adding PMMA to the gap using the custom jig. One group was not corrected (CN). These were trimmed as above. Each group had 10 specimens. Crowns were returned to their original ITA oriented exactly as they were constructed. Microscopically, marginal gaps at 0^o, 90^o, 180^o, and 270^o between the crown and ITA were measured to the nearest μm. These were averaged for each specimen. The Student's t-test statistically compared SY and SN as well as CY and CN. Results: Significant difference was found between SY (61 μm ± 13) and SN (27 μm ± 5) as well as between CY (61 μm ± 13) and CN (31 μm ± 4). Conclusions: Marginal gaps are larger with sleeves than without them. Correcting of margins in deep gingival cuff situations yields smaller gaps.