Mini-implants for direct or indirect orthodontic anchorage

DATA SOURCES: Studies were sourced using Medline, the Cochrane Library and hand searches of key orthodontic journals.

STUDY SELECTION: The review was restricted to peer-review articles (randomised controlled studies, prospective clinical studies and retrospective clinical studies) dealing with mini-implants (implant diameter smaller than 2.5 mm) and conducted in humans. Articles were excluded if: they dealt with standard dental implants, onplants (palatal implants), miniplates used as orthodontic anchorage, or miniscrews or microscrews for dental surgery, and implant materials research; if they were animal studies, in-vitro studies, case reports and case series, or technique presentations of mini-implants and micro-implants, review articles and letters; or if they were articles that did not meet the objective of this review or were reported in a language other than English.

DATA EXTRACTION AND SYNTHESIS: Data were extracted independently by two authors, with disagreements resolved by discussion. Study quality was assessed. A qualitative synthesis was conducted.

RESULTS: Sixteen articles met the inclusion criteria and, because of quality limitations, the literature was summarised in two broad areas, placement-related and loading-related factors.

CONCLUSIONS: Mini-implants are effective as anchorage, and their success depends on proper initial mechanical stability and loading quality and quantity.