Accuracy of digitization obtained from scannable and nonscannable elastomeric impression materials

Clinical evaluation of marginal fit of uncemented CAD-CAM monolithic zirconia three-unit restorations in anterior areas, using scannable and conventional polyvinyl siloxane impression materials

BACKGROUND

The accuracy of impression techniques determines the marginal fit of fixed prostheses. Marginal accuracy plays a main role in the success and failure of treatments. This in-vivo study evaluated the marginal fit of anterior three-unit monolithic zirconia fixed partial dentures (FPDs) using conventional and scannable polyvinyl siloxane impression materials.

METHODS

Ten patients were selected to replace the lateral teeth with a three-unit monolithic zirconia bridge. For each patient, in the first group, an impression was made with a two-step putty-wash technique using scannable polyvinyl siloxane material (BONASCAN; DMP, Greece). In the identical session, as the second group, an impression of conventional putty-wash polyvinyl siloxane was taken (BONASIL A⁺ Putty; DMP, Greece). The marginal discrepancy was measured through the replicas, which were cut perpendicularly within the buccolingual and mesiodistal directions. An Independent t-test was employed for data analyses (P < 0.05).

RESULTS

The marginal discrepancy in a conventional method for central abutment in mid-buccal, mid-lingual, mid-mesial, and mid-distal was higher than in the scannable method but it was not significant (P > 0.05). Also, the marginal discrepancy for canine abutment in the conventional method was higher than in the scannable method, but it was not significant, either (P > 0.05).

CONCLUSIONS

FPDs fabricated from both scannable and conventional impression materials were not superior to each other in marginal fit for both central and canine abutments by evaluation using the replica technique.

Digital replication of the peri-implant soft tissue contour of implant-supported crowns: A dental technique

Making an intraoral digital scan of the emergence profile is a clinical challenge. The peri-implant soft tissue collapses after removal of an interim prosthesis, which compromises the correct design of a definitive implant-supported prosthesis. Although techniques are available for digitally reducing such a distortion, achieving a correct alignment of scans to replicate the internal and external characteristics of the peri-implant tissue is still challenging. This article describes an alternative technique for achieving a precise alignment of the peri-implant soft tissue emergence profile generated with an interim prosthesis.