Prospective study on titanium bar-retained overdentures:: 2-year results

Within a monometallic concept 29 patients received titanium bar-retained mandibular overdentures on 2 IMZ implants. The study had a prospective design with 3 months recall intervals. One of 58 implants failed after 11 months. There were no significant differences of the mean plaque scores (Silness, Loe) and the mean sulcus bleeding scores (Muhlemann, Son) at the abutments between baseline, 12 months and 24 months. Less than 40% of the subjects showed plaque score zero at 24 months. However, 89% exhibited sulcus bleeding score zero indicating health f the periimplant soft tissues in most cases. Plaque at the basal site of the bar was scored separately at additional measuring points located at the central area acid the contact areas between bar and abutments. Bar plaque scores nearly doubled between baseline and 12 months and remained high at 24 months. Median maximal vertical bone loss around the implants was 1.7 mm after 2 years. Bone loss did not exceed one quarter of the implant length in 79%. The monometallic concept in bar-retained overdentures on 2 implants proved its clinical suitability except for the applicability of pure titanium for bar clips. Plaque formation beneath the bar seems to be one of the major clinical problems.