Potential risk factors of prosthetic implant failure: occlusal overload prevention

Aim: The aim of this study was to evaluate the effects of abnormal occlusal forces on dental implants in patients with temporomandibular disorders (TMD), and to focus on concepts and the clinical procedures to reduce the potential risk factors for implant failure. Material and Methods: Twenty-eight TMD patients were compared to 28 no-TMD patients in which were inserted 267 implants with the same features as number, size, position, design. Another experimental group of 30 TMD patients treated by prevention protocol was assessed. Besides, were considered type of restoration, cemented or screwed, malocclusion type, smoking, load timing. The heavy force of compression, clenching and grinding, as in bruxism, simultaneously applied strong pressures to the implants, crestal bone, restorations and temporomandibular joints. This was a potential risk factor for crestal bone loss, loss of integration before and after restoration, abutment screw loosening and fracture, implant fracture, decementation of restorations and fracture of the porcelain. Results: The 5 years follow-up showed a 58% of soft tissues and prosthetic complications (on 137 implants) in TMD patients versus a 13% (on 130 implants) in non TMD patients. When TMD patients were undergone to occlusal overload prevention protocol, the complications were diminished to 15% (P< .001). The results indicate that increasing the number of implants and reducing cantilevers decreases the stress on each one; using the longest and widest implant possible increases implant/bone surface area and reduces also strain on the restorations. Also implant design, occlusal table size, the direction, duration and magnification of the forces influences the stress at the crestal bone/implant surface. Anterior guidance during excursive movements reduces forces and eliminate all lateral occlusal contact. Conclusion: Developing treatment plan that control the chronic bruxism through night-guards and modify the occlusal forces on implants and their restorations, patients with temporomandibular disorders and bruxism can be candidates for implants.