American Journal of Orthodontics and Dentofacial Orthopedics
Original articleEffectiveness of early orthodontic treatment with the twin-block appliance: A multicenter, randomized, controlled trial. Part 1: Dental and skeletal effects☆
Section snippets
Material and methods
This investigation had the null hypotheses that orthodontic treatment provided with the Twin-block appliance during the transitional dentition stage of development has no effect on (1) anteroposterior relationship of the maxilla to the mandible after treatment, (2) overjet, and (3) dental malocclusion as recorded by the peer assessment rating (PAR).
Fourteen hospital-based orthodontic specialists in the United Kingdom (UK) agreed to take part in the study. Each had undergone basic specialty
Results
A total of 174 patients were enrolled into the project. Of these, 89 (41 girls, 48 boys) were allocated to the Twin-block and 85 (39 girls, 46 boys) to the control group. Enrollment started in March 1997 and was completed by August 1999. The last data collection was done in November 2000. The average age of the children was 9.7 (SD = 0.98) years for the treatment group and 9.8 (SD = 0.94) years for the control group.
We found that 14 (16%) of the children who were enrolled in the treatment group
Skeletal versus dental change
One of the most important morphologic findings of this study was that early intervention with a Twin-block appliance successfully reduced dental overjet, molar discrepancies, and severity of malocclusion. This was achieved by a combination of dental and skeletal change. Interestingly, the amounts of overjet and molar change that were attributable to skeletal change were 27% and 41%, respectively, and this was made up of growth modification of both the mandible and the maxilla to a similar
Conclusions
In a multicenter setting in the UK, early orthodontic treatment with the Twin-block appliance resulted in substantial reduction in the overjets of children with Class II malocclusion. This was mainly due to dentoalveolar change, with a small element of favorable skeletal change. The magnitude of the patient’s initial discrepancy was related to the outcome of treatment. This study reinforces the findings of other, similar randomized, controlled trials that suggest that early functional appliance
Acknowledgements
The authors thank the patients who took part in this study and the supporting staff for their additional work at the treatment centers.
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Supported by the Medical Research Council (G9410454).