Maxillary overdenture on three implants retained by low-profile stud attachments - A prospective cohort study

Clinical data are needed on long-term outcomes of removable implant-supported prostheses in the fully edentulous maxilla as a function of the number of implants, effects of the attachment system and other clinical variables.

To restore individuals with an edentate maxilla with a metal-reinforced removable prosthesis without palatal coverage retained by low-profile stud attachments on three implants.

The regional ethics committee approved a prospective cohort study that included all consecutive patients treated in a private speciality clinic. Primary outcomes were patients reported, that is denture satisfaction scale and oral health-related quality of life - OHIP-20. Secondary outcomes were implant- (bone loss, implant complications and peri-implant conditions) and prosthesis-related (prosthesis complications, maintenance needs and mucosa condition).

Thirty-two study participants were recruited between March 2007 and October 2016 and followed for a minimum of five years. According to Kruskal-Wallis tests, the OHIP-20 and Denture Satisfaction Scale questionnaire pre-treatment scores differed significantly. After an average of 6.7 years, peri-implant bone loss of more than 2 mm was observed on 17% of all implants, while no or minor bone loss was seen on 38%. The estimated success of implants was 0.95 at 168 months. The estimated success of the prosthesis, that is no adverse events or need for any repairs, was 0.55 at 156 months.

The positive findings in the current clinical study strengthen the notion that for many individuals with an edentulous maxilla, a removable prosthesis retained by three implants fitted with low-profile stud-attachment is a reliable technical solution.