Occlusal considerations in implant therapy: clinical guidelines with biomechanical rationale Yongsik Kim Tae-Ju Oh Carl E. Misch Hom-Lay Wang Authors’ affiliations: Yongsik Kim, Tae-Ju Oh, Carl E. Misch, Hom-Lay Wang, Department of Periodontics/Prevention/ Geriatrics, University of Michigan School of Dentistry, Ann Arbor, MI, USA Correspondence to: Prof. Hom-Lay Wang Department of Periodontics/Prevention/Geriatrics University of Michigan School of Dentistry 1011 North University Avenue Ann Arbor, MI 48109-1078 USA Tel.: þ 1-734-763-3383 Fax: þ 1-734-936-0374 e-mail: homlay@umich.edu Key words: dental implant, implant longevity, implant occlusion, overloading Abstract: Due to lack of the periodontal ligament, osseointegrated implants, unlike natural teeth, react biomechanically in a different fashion to occlusal force. It is therefore believed that dental implants may be more prone to occlusal overloading, which is often regarded as one of the potential causes for peri-implant bone loss and failure of the implant/implant prosthesis. Overloading factors that may negatively influence on implant longevity include large cantilevers, parafunctions, improper occlusal designs, and premature contacts. Hence, it is important to control implant occlusion within physiologic limit and thus provide optimal implant load to ensure a long-term implant success. The purposes of this paper are to discuss the importance of implant occlusion for implant longevity and to provide clinical guidelines of optimal implant occlusion and possible solutions managing complications related to implant occlusion. It must be emphasized that currently there is no evidence- based, implant-specific concept of occlusion. Future studies in this area are needed to clarify the relationship between occlusion and implant success. Occlusal overload is often regarded as one of the main causes for peri-implant bone loss and implant/implant prosthesis fail- ure. Studies have suggested that occlusal overload may contribute to implant bone loss and/or loss of osseointegration of suc- cessfully integrated implants (Adell et al. 1981; Rosenberg et al. 1991; Quirynen et al. 1992; Rangert et al. 1995; Isidor 1996, 1997; Miyata et al. 2000). In con- trast, others believed that peri-implant bone loss and/or deosseointegration are primarily associated with biological com- plications such as peri-implant infection (Tonetti & Schmid 1994; Lang et al. 2000). They questioned the causality of occlusal overloading for peri-implant tissue loss due to insufficient scientific evid- ences. However, it needs to be stressed that occlusal overload can cause mechan- ical complications on dental implants and implant prostheses such as screw loosening and/or fracture, prosthesis fracture, and implant fracture, eventually leading to compromised implant longevity (Schwarz 2000). Unlike natural teeth, osseointegrated implants are ankylosed to surrounding bone without the periodontal ligament (PDL), which provides mechanoreceptors as well as shock-absorbing function (Schulte 1995). Moreover, the crestal bone around dental implants may act as a ful- crum point for lever action when a force (bending moment) is applied, indicating that peri-implant tissues could be more susceptible to crestal bone loss by applying force. Literature has reported that the clinical success and longevity of dental implants can be achieved by biomechan- ically controlled occlusion (Rangert et al. 1989, 1997; Adell et al. 1990; Misch Copyright r Blackwell Munksgaard 2004 Date: Accepted 5 January 2004 To cite this article: Kim Y, Oh T-J, Misch CE, Wang H-L. Occlusal considerations in implant therapy: clinical guidelines with biomechanical rationale. Clin. Oral Impl. Res. 16, 2005; 26–35 doi: 10.1111/j.1600-0501.2004.01067.x 26