Use of Zirconia Onlays in Removable Complete Denture Opposing Natural Dentition: A Case Report

Melissa Pascual, DDS

Department of Restorative Dentistry and Prosthodontics

University of Texas School of Dentistry at Houston

 

Objective: This technique will help prevent occlusal wear of the removable complete denture opposing natural dentition by utilizing zirconia onlays.

Case History:

An 83-year-old female presented for evaluation of a worn and ill-fitting mandibular complete denture opposing natural dentition restored with porcelain crowns. Upon initial examination, the occlusal surfaces of the denture were found to be severely worn, leading to a loss of vertical dimension of occlusion and a Class III malocclusion. A treatment plan was proposed to fabricate zirconia onlays for her new prosthesis.

Technical Steps:

A new mandibular removable complete denture was fabricated using conventional methods. A digital scan of the denture opposing her natural dentition was obtained with a Trios 4 scanner to serve as the pre-operative scan. The mandibular denture teeth were then prepared to achieve a minimum occlusal reduction of 2 mm, incorporating a central groove feature to facilitate the seating of the restorations. A scan of the preparations was obtained and aligned with the pre-operative scan using Exocad CAD software. The onlays were designed by adapting the restoration contours to the denture teeth in the pre-operative scan. The onlays were milled on a Planmeca PlanMill 50S using Ivoclar IPS e.max ZirCad Prime, then sintered and polished according to the manufacturer's instructions. Both the denture teeth and onlays were air-abraded with aluminum oxide and steam-cleaned. Acrylic monomer was applied to the denture teeth, while Z-Prime Plus was used on the intaglio surfaces of the onlays. The onlays were then cemented in place using 3M RelyX Unicem.

Conclusion: 

The use of zirconia onlays in removable complete dentures facilitates the preservation of vertical dimension of occlusion and provides a cost-effective technique compared to gold onlays.