Orthodontic anchorage--Evidence-based evaluation of anchorage capacity and patients' perceptions.

Orthodontic anchorage is the ability to resist unwanted reciprocal forces and reinforcement of anchorage by supplementary appliances, in or outside the mouth, is often needed to obtain successful results. In the last 10 years, interest in appliances that use implants has been growing. Successful orthodontic treatment demands effective methods and systematic evaluation of different treatment approaches is therefore essential. Several studies on the efficiency of various anchorage systems have been published, but a critical appraisal or interpretation of evidence that systematically considers validity, results, and relevance has not been made. Analysis of treatment modalities must also include patients' perceptions and potential side-effects. The overall aim of this thesis was to evaluate a new anchorage technique that incorporates osseointegration and compare it with conventional methods concerning effects on tooth movements in adolescents and their acceptance and experience of the additional surgical procedures that osseointegration involves. The following anchorage systems were analyzed: Onplant system, Orthosystem implant, headgear and transpalatal bar. This thesis was based on four studies: Paper I systematically reviewed the efficiency of orthodontic anchorage systems and interpreted the methodological quality of the selected studies from an evidence-based perspective. The literature search spanned January 1966 - December 2004 and was later extended to July 2007. Paper II, a methodological study involving 60 adolescent patients, examined the validity and reliability of a new questionnaire for assessing adolescent patients' perceptions of orthodontic treatment. The questionnaire was based on focus group interviews. Papers III and IV were randomized controlled trials involving 120 adolescent patients in orthodontic treatment. Paper III evaluated and compared adolescent patients' perceptions of premolar extractions and surgical placement of Onplants and Orthosystem implants. Paper IV compared anchorage capacities of the four systems. These conclusions were drawn: The scientific evidence, found in the review, was too weak to evaluate the efficiency of various anchorage systems (conventional and osseointegrated) during space closure after premolar extraction, and most studies have quality problems. Future randomized controlled trials are recommended. The new questionnaire, developed from focus group interviews, had overall acceptable to good reliability and high face validity. It can therefore be recommended for use in the assessment of adolescents' experiences of orthodontic treatment. Pain intensity after surgical placement of an Orthosystem implant was less than after Onplant installation and premolar extraction. Pain intensity after Onplant installation and premolar extractions were comparable. With respect to pain intensity, discomfort, and analgesic