Four implant bar-connected implants sufficient to support a maxillary overdenture

Abstract

Randomised controlled trial. Edentulous patients aged at least 18 years with lack of retention and stability of the upper denture and lower denture were randomised to receive a maxillary overdenture supported by either four or six bar-connected implants. The primary outcome measure was change of radiographic bone level. Secondary outcome measures were implant survival, overdenture survival and soft tissue conditions (plaque index, presence of calculus, gingiva index, sulcus bleeding index and pocket probing depth). These were scored at placement of the overdenture and after 12 months of loading. Patient satisfaction was also scored at baseline and at 12 months. Forty-nine patients (one drop out) completed the one year follow-up. Mean marginal bone resorption was 0.24 ± 0.32 mm in the four implants group and 0.25 ± 0.29 mm in the six implants group. Implant survival was 100% in the four implants group and 99.3% in the six implants group (one implant lost). Overdenture survival was 100% in both groups. There were no differences in the soft tissue outcomes between the groups. Patient satisfaction had improved in both groups. After one year a bar-connected maxillary overdenture on four or six implants results in a comparable treatment outcome with high implant survival, healthy peri-implant tissues and high patient satisfaction. For reasons of cost-effectiveness, treatment with four bar-connected implants to support a maxillary overdenture is preferred.