A Comparative Evaluation of Vertical Marginal Gap for Vented and Precemented Cad-Cam Zirconium Copings on Angulated Abutments: An In vitro Study

OBJECTIVE: To evaluate vertical marginal gap after cementation of Zr (zirconium) copings with palatal vent, open vent, and precementation technique on angulated abutments resulting from cement entrapment between intaglio surface of copings and angulated abutments. MATERIALS AND METHODS: Twenty-four angled abutments and 24 CAD-CAM Zr copings were assigned to three groups depending on the type of cementation technique, comprising eight copings with palatal vent, open vent, and no vent, respectively. Vertical marginal gaps between abutment shoulder and coping margin were evaluated at four points: buccal, palatal, mesial, and distal. The readings were statistically analyzed. RESULTS: The average mean value of vertical marginal gap at all sites for Group A with palatal vent was 158.45, for Group B with open vent was 151.84, and for Group C using precementation technique was 163.58. A statistically non-significant difference was seen for values between all sites (P > 0.05) for all groups. CONCLUSION: The average vertical marginal gap for Group B was comparatively lower compared to Groups A and C.