Miniscrews as Anchorage Device for Orthodontic Treatment

Miniscrews as Anchorage Device for Orthodontic Treatment - Randomized Controlled Trials on Anchorage Capacity, Cost Efficiency and Patient Acceptance

The purpose of this trial is to study and compare two different anchorage techniques. Adolescent patients in need for orthodontic treatment are randomized into Group A and B. Both groups are treated with extractions of the maxillary first premolars and fixed appliance. Anchorage is reinforced by miniscrews in Group A and by molarblock in Group B.

The hypotheses are:

• that placement of miniscrews does not cause more pain or discomfort than premolar extractions
• that molarblock provides increase of anchorage
• that miniscrews have a better anchorage capacity than molarblock
• that miniscrews are more cost-efficient than conventional anchorage techniques

Participants are recruited from the orthodontic specialist clinic in Gävle, Sweden. After informed consent participants are randomized into Group A and B. The treatment starts with extractions of the maxillary first premolars. Extractions are performed by the participants´ general practitioner. Orthodontic treatment starts after the tooth extractions.

All participants get treatment with fixed appliance according to the straight wire concept (3M Victory brackets, .022 slot size, McLaughlin-Bennet-Trevesi prescription). The recommended wire sequence is: .016 Heat Activated Nickel Titanium, .019x.025 Heat Activated Nickel Titanium, .019x.025 Stainless Steel. Treatment time is about two years.

The following measurements are taken at:

T0 (Before treatment start): Study models, baseline questionnaire,

T1 (after tooth extractions, before the orthodontic treatment): Study models, cephalographic x-ray, questionnaire at the evening after tooth extractions, questionnaire one week after tooth extractions.

T2 (After miniscrew placement (Group A), Before space closure): Study models, cephalographic x-ray, questionnaire at the evening after miniscrew placement, questionnaire one week after miniscrew placement.

T3 (After space closure and miniscrew removal): Study models, cephalographic x-ray, questionnaire after screw removal

Inclusion Criteria:

• Adolescents in need of orthodontic treatment with fixed appliance including extractions of the maxillary first premolars
• Need for Anchorage reinforcement
• Permanent dentition including the maxillary second molars in occlusion (DS4M2 according to Björk)
• Regular dental care in Sweden since the age of three.

Exclusion Criteria:

• Experience of previous orthodontic treatment
• Need for orthognathic surgery
• Need for maximum anchorage.