Microthreaded Implants and Crestal Bone Loss: A Systematic Review

This systematic literature review investigated the effect of microthreaded-neck dental implants on crestal bone loss. Using the participants, interventions, comparison groups, outcomes, and study design (PICO) system, we addressed the following focused question: Do microthreaded-neck dental implants positively affect the crestal bone level around dental implants? We searched 3 electronic databases to find articles published between January 1995 and June 2016 that contained any combination of the following keywords: dental implant, microthread, microthreaded, crestal bone level, crestal bone loss, and alveolar bone level. We excluded case reports, review articles, letters to the editor, commentaries, and articles published in a language other than English. We found a total of 70 articles. After eliminating duplicates and applying PICO eligibility criteria, we selected only articles that reported the results of randomized controlled trials, prospective or retrospective cohort studies, case control studies, cross-sectional studies, or other types of clinical trials that compared the microthreaded implant design with other implant designs. We were left with 23 articles for review. The 23 articles reported crestal bone loss ranging from .05 mm to .9 mm, with a range of 12 to 96 months of follow-up. Less crestal bone was lost with dental implants that had a microthreaded neck design than with machined-surface or conventional rough-surface dental implants. Thus, microthreaded dental implants are a better choice than are implants with other designs. Future studies should use standardized imaging techniques to evaluate the placement of these implants in bone-augmented sites.