Comparison of excess cement around implant crown margins by using 3 extraoral cementation techniques.

STATEMENT OF PROBLEM: Extrusion of excess cement into the subgingival area around implant-supported crowns is associated with detrimental inflammatory response, but controlling this excess material remains a challenge. PURPOSE: The purpose of this in vitro study was to perform a comparative analysis of 3 extraoral cementation techniques to reduce excess extruded cementation material around implant-supported crowns. MATERIAL AND METHODS: Forty-four internal connection implant replicas were embedded in acrylic resin to form the experimental model. Cementable abutments were tightened onto the implants. Zirconia crowns were luted to each of the cementable abutments by using 1 of 4 techniques: control, pattern resin analog that was 3D-printed, fast-setting polyvinyl siloxane analog, and putty index analog. Extruded excess cement was collected at each luted crown and weighed. RESULTS: The mean residual weight of excess cement found in the pattern resin analog technique group was the least (0.087 mg), followed by the polyvinyl siloxane analog technique group (1.678 mg). The putty index analog technique group reported the least reduction of excess extruded cement (7.621 mg). All techniques produced substantially less extruded cement than the control (85.166 mg). In a 1-way analysis of variance, statistically significant differences (P<.001) were found among all the test techniques. Pairwise comparisons also found that all 3 test techniques were statistically different from each other. CONCLUSIONS: The pattern resin (3D-printed) analog technique produces the least amount of extruded excess cement at an implant-supported crown, limiting detrimental impact on peri-implant tissue health.

Root and canal configurations of maxillary premolars in a South African subpopulation using cone beam computed tomography and two classification systems.

This cone beam computed tomography (CBCT) study aimed to describe the maxillary premolar anatomy of a South African subpopulation using two classification systems. A total of 601 premolars were evaluated. For each tooth, the root number and canal configurations were described using the classification systems devised by Vertucci (1984) and Ahmed et al. (2017). Correlations between root number and sex were determined using the chi-squared test (P = 0.05). Two roots were present in approximately half of all maxillary first premolars (54.1%, n = 171/316). The majority of maxillary second premolars displayed one root (78.2%, n = 223/285). Single-rooted maxillary second premolars were more common in females (P < 0.05). The Vertucci type IV configuration was most prevalent in the maxillary first premolars. In contrast, maxillary second premolars showed a greater tendency toward Vertucci's type I configuration. The classification proposed by Ahmed et al. indicated the most prevalent maxillary first premolar configuration to be 2MP B1P1. The most common configuration among the maxillary second premolars was 1 MP1. Diverse root and canal anatomical presentations were found in this subpopulation. Both classification systems adequately describe maxillary premolar anatomy; however, the system proposed by Ahmed et al. may more accurately describe complex teeth.