One-year results of maxillary overdentures supported by 2 titanium-zirconium implants - implant survival rates and radiographic outcomes

ObjectiveTo assess implant survival rates and peri-implant bone loss of 2 titanium-zirconium implants supporting maxillary overdentures at 1year of loading. Material and MethodsTwenty maxillary edentulous patients (5 women and 15 men) being dissatisfied with their complete dentures were included. In total, 40 diameter-reduced titanium-zirconium implants were placed in the anterior maxilla. Local guided bone regeneration (GBR) was allowed if the treatment did not compromise implant stability. Following 3 to 5months of healing, implant-supported overdentures were inserted on two ball anchors. Implants and overdentures were assessed at 1, 2, 4, and 8weeks after implant insertion and 2, 4, and 12months after insertion of overdentures (baseline). Standardized radiographs were taken at implant loading and 1year. Implant survival rates and bone loss were the primary outcomes. ResultsNineteen patients (1 dropout) with 38 implants were evaluated at a mean follow-up of 1.1years (range 1.0-1.7years). One implant failed resulting in an implant survival rate of 97.3%. There was a significant peri-implant bone loss of the implants at 1year of function (mean, 0.7mm, SD = 1.1mm; median: 0.48mm, IQR = 0.56mm). ConclusionsThere was a high 1-year implant survival rate for edentulous patients receiving 2 maxillary implants and ball anchors as overdenture support. However, several implants exhibited an increased amount of bone loss of more than 2mm. Overdentures supported by 2 maxillary implants should thus be used with caution as minimally invasive treatment for specific patients encountering problems with their upper dentures until more long-term data is available.