Occlusal overload and bone/implant loss.
OBJECTIVE
The aim of this search was to assess the biological consequences that overload might have on already osseointegrated oral implants through a systematic screening of the scientific literature.


METHODS
Detailed searches through PUBMED, OVID, EMBASE and LILACS databases were made. Articles published up to December 2011 and those reported on the clinical, radiographic and/or histological outcome of oral implants subjected to so-called overload were considered eligible for inclusion. Identified studies were assessed by one non-blinded reviewer according to well-defined inclusion and exclusion criteria. When doubt arose, the co-authors were counselled until final agreement was obtained. The PICO questions formulated was:"what is the effect of overload vs. no overload on bone/implant loss in clinically stable implants?"


RESULTS
The database searches as well as additional hand searching, resulted in 726 potentially relevant titles. Eventually, 16 clinical and 25 animal studies were considered relevant to the topic. After inclusion/exclusion criteria assessment, all clinical studies and all but three animal studies and one systematic review were considered at high risk of bias and excluded. The included animal studies did not reveal an association between overload and peri-implant bone loss in the absence of peri-implant inflammation, whereas in its presence, overload seemed to aggravate the peri-implant tissue breakdown.


CONCLUSIONS
The effect of implant overload on bone/implant loss in clinically well-integrated implants is poorly reported and provides little unbiased evidence to support a cause-and-effect relationship. The PICO question remained unanswered. At the animal level, "overload", mimicked by supra-occlusal contacts acting in an uninflamed peri-implant environment, did not negatively affect osseointegration and even was anabolic. In contrast, supra-occlusal contacts in the presence of inflammation significantly increased the plaque-induced bone resorption.
KU Leuven, Clinical Unit for Prosthetic Dentistry, BIOMAT KU Leuven, Department of Oral Health Sciences & Dental Clinics University Hospitals, KU Leuven (Catholic University of Leuven), Kapucijnenvoer 7 blok a bus 7001, BE, 3000, Leuven, Belgium. Ignace.Naert@med.kuleuven.be
Ignace
I
Naert
Joke
J
Duyck
Katleen
K
Vandamme
D016301:Alveolar Bone Loss / Q000209:etiology*; D000818:Animals; D001696:Biomechanical Phenomena; D001732:Bite Force; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006801:Humans; D016348:Osseointegration; D057873:Peri-Implantitis / Q000209:etiology; D012307:Risk Factors; D013314:Stress, Mechanical
D015921:Dental Implants