Efficacy and Predictability of Short Dental Implants (< 8 mm): A Critical Appraisal of the Recent Literature

Purpose: This review of literature was conducted to evaluate the predictability of treatment outcomes with short dental implants (SDI), ie, implants shorter than 8 mm. Materials and Methods: The review included studies, published between January 1990 and July 2011, that (1) involved SDI ( 8 mm) placed in human jaws, (2) had a minimum of 20 SDI in their analysis, (3) provided data on survival rates, and (4) reported a minimum observation period of at least 3 months after placement. Results: Forty-one studies fulfilled the above criteria; only 17 of these studies reported outcomes with microrough surface SDI. Six different lengths (4, 5, 6, 6.5, 7 and 7.5 mm) of microrough surface SDI with varying diameters (3.5 to 6 mm) were identified in the studies. A total of 1,828 microrough surface SDI were inserted and 45 failures were reported. Observation periods ranged from 3 months to 9 years. The reported survival rates for SDI ranged from 92.2% to 100%. From a total of 1,123 SDI inserted in specified jaw locations, failures were observed more often in the maxilla (n = 297, failed = 13) than in the mandible (n = 826, failed = 19). The review did not identify any correlation between implant diameter and survival for the microrough SDI. Conclusions: Microrough surface short implants (6 to 7.5 mm) appear to provide favorable survival rates and, therefore, can be predictably employed for simplification of implant therapy in situations of reduced alveolar heights in the posterior jaw segments. Keywords: dental implant, implant length (< 8 mm), literature review, short dental implants, treatment outcomes