Evaluation of the variable anchorage straightwire technique using Ricketts' growth prediction.

The purpose of this retrospective study was to evaluate the treatment effects of the variable anchorage straightwire technique (VAST) in Angle Class II patients using Ricketts' growth prediction analysis. The subjects belonged to two groups: a control, consisting of 30 untreated Class II Swedish individuals (20 girls, 10 boys) with a mean age of 11.2 years, and the other 29 Swedish patients (14 girls, 15 boys), mean age 12.6 years, post-normal and with an increased overbite (OB), treated with the VAST. Two lateral cephalograms were available for every individual. Growth prediction according to Ricketts' visual treatment objective (VTO) was used to estimate the expected growth increments for a 2-year period. It was first used in the control group to determine its validity and then applied to the treated group to evaluate the net effects of treatment. Cephalometric evaluation based on Ricketts' analysis and additional dentoalveolar variables were carried out. Statistical analysis was undertaken using a paired Student's t- and Wilcoxon signed ranks tests. The method of predicting growth according to the VTO was, in general, valid in the untreated subjects, apart from the inclination of the lower incisors, where the proclination had been underestimated. In the treated group, the net effects of treatment were significant for the dentoalveolar variables: reduction of overjet (OJ) and OB, proclination and relative intrusion of the lower incisors, extrusion of the molars, and increase in lower face height. The growth prediction method according to VTO was found to be valid in a sample of Swedish post-normal children concerning skeletal and dentoalveolar variables. The VAST treatment net effects in these growing patients were achieved mainly by dentoalveolar changes.

The variable anchorage straight wire technique compared with the straight wire technique in deep overbite correction.

The aim of this retrospective study was to compare the treatment results and the number of required treatment appointments between the variable anchorage straight wire technique (VAST) and the straight wire (SW) technique. The subjects were 53 Caucasian patients of both sexes (25 males and 28 females, mean age 13.5 years at the start of treatment), with an overjet > or = 4 mm and an overbite > or = 3 mm. The patients were divided into four groups, VAST (n = 31) or SW (n = 22), extraction or non-extraction, and were treated by the same orthodontist. Variables from two lateral cephalograms obtained before and at the completion of active treatment, and the number of scheduled appointments were compared between the two techniques. The main difference between the two techniques was the bracket design. With the VAST, the bracket allowed both tipping and parallel movements with the possibility to combine double archwires. Due to the influence of the Begg technique, no extra-oral traction was needed in the VAST groups and Class II elastics were used at the start of treatment. Both techniques seemed to produce equal treatment results. However, in this study, it was shown that in deep overbite correction, the VAST required fewer scheduled appointments than the SW technique.