Objectives: This research was carried out to evaluate the effect of Polyetheretherketone (PEEK) as denture base material on peri-implant crestal bone level changes in edentulous patients rehabilitated with implant-supported primary-secondary bar overdenture and retained attachments attached the body of the bar constructed by CAD / CAM technology.
Materials and Methods: Twenty completely edentulous patients complaining from insufficient retention of their mandibular denture were selected to participate in this study. All the patients were rehabilitated with an implant-supported bar overdenture. For All patients three implants (3.7mm) in diameter (11mm) in length were inserted in the interforamenal region using computer guided surgical template. Four months later, Cast bar with two semi precession attachment at the distal ends of the bar was constructed, The cast bar was scanned using bench laser scanner to obtain virtual model with the bar, the housing on the top of the bar and the female part of the attachment was designed using computer aided designing (CAD) the meld into wax by computer aided manufacturing (CAM). The CAD/ CAM wax pattern of housing and the female part of the attachments were transferred into acetal resin using the injection molded technique. Overdentures were constructed for all patients following the conventional technique. According to the denture base material, a toss coin was made to randomly divided the patients into two equal groups; group I received mandibular implant-retained overdenture were processed using heat cured acrylic resin, following the long curing cycle (heated at 78C° for eight hours), while for
group II Polyetheretherketone (PEEK) lower overdenture was constructed, using the injection-molding technique. Radiographic evaluation of peri-implant bony changes was made using standardized long cone paralleling technique with custom made acrylic template and the Rinn-xcp at insertion, six, twelve and twenty four months were measured and statistically analyzed. The significant level was set at P ≤ 0.05P . ANOVA for repeated measures test was used to compare between follow up periods within groups and when statistically significant it was followed by simple main effect analysis with Bonferioni correction. One way ANOVA test was used to compare between groups at different follow up periods. Results. Both groups showed a statistically insignificant increase loss in crestal bone height around the implants. Although the data obtained from table1 revealed increase in the amount of bone changes for group I and Group II compared to group I during the follow up period statistical analysis of the data using ANOVA test for repeated measures revealed no significance difference(P ≥ 0.05) .
Conclusion: CAD/ CAM technology and use of Polyetheretherketone (PEEK) as denture base material should be considered whenever possible to preserve the implant supporting structures in implant bar retained overdenture.