Biologic and prosthetic complications with acrylic and porcelain fixed hybrid prosthesis used for rehabilitation of edentulous mandible according to the “All on four” implant concept. A 3 year prospective study

Abstract

Purpose: The aim of this study was to evaluate biologic and prosthetic complications with acrylic and porcelain fixed hybrid prosthesis used for rehabilitation of edentulous mandible according to the “All on four” concept.Materials and methods: Ten edentulous patients received new maxillary and mandibular dentures. Four implants were inserted in the inter-foraminal area of the mandibular jaw according to the “All on four concept” and the implants were immediately loaded with lower denture. After 3 months, the patients were randomly assigned into two equal groups: Group I: received fixed ceramometal prosthesis (PFM), Group II; received metal acrylic hybrid prosthesis (MAP). Biological and prosthetic complications were measured for provisional dentures after 3 months of loading and for definitive prosthesis after 3 year. Results: The most common biological complication was increased pocket depth and bone loss which was significantly higher for PFM compared to MAP. Regarding provisional denture, the most common complication was denture fracture and prosthetic screw loosening. The most common complication for definitive prosthesis was crown fracture, teeth wear and prosthetic screw loosening. Crown fracture and teeth wear were higher in MAP and abutment screw loosening was higher in PFM.Conclusion: Within the limitation of the current study PFM and MAP could be used successfully for All on four implant rehabilitation of edentulous mandible. However, MAP may be advantageous than PFM regarding biologic complications (increased pocket depth and marginal bon loss) and abutment screw loosening. On the other hand, PFM may be preferred than MAP in terms of crown fracture and teeth wear/replacement.