Chesterfield Micro-implant Study Involving Three Types of Anchorage Methods in Orthodontics

Research problem: Anchorage reinforcement is effective with headgear provided patient compliance is optimal. Nance palatal arch have also been shown to be effective. Microscrews despite their popularity however have no scientific evidence to support their use. Aim: To compare the effectiveness of 3 methods of anchorage reinforcement 1) headgear 2) Nance palatal arch 3) orthodontic micro-screws. Hypothesis: There is no difference in the amount of anchorage loss between the three methods of anchorage reinforcement. Design: Randomized clinical trial. Setting: District General Hospital orthodontic department Participants: 78 patients requiring "absolute anchorage". Interventions: The subjects will be randomized into 3 groups. In group 1 headgear will be requested 12-14 hours per day. In group 2 a nance palatal arch will be placed for use as intra oral anchorage reinforcement. In group 3, orthodontic micro-screws will be used for anchorage. Method of investigation: The study will be of 78 'absolute anchorage' patients older than 12 years randomly assigned to one of three groups of anchorage reinforcement Data analysis: The data will be analysed on an intention to treat basis. Basic descriptive statistics and uni-variate tests will initially be done to explore the data. Final data analysis will involve the relevant multi-variate statistical modeling. I took professional statistical advice from a senior statistician at the University of Manchester. Analysis of covariance was used and Headgear (as our default treatment) was used as the reference category. Results with Nance and TADs are relative to the reference category of headgear.