Article

Incremental versus maximum bite advancement during twin-block therapy: A randomized controlled clinical trial

Burnley General Hospital, Burnley, United Kingdom.
American Journal of Orthodontics and Dentofacial Orthopedics (Impact Factor: 1.44). 12/2004; 126(5):583-8. DOI: 10.1016/S088954060400602X
Source: PubMed

ABSTRACT The aim of this study was to evaluate the effectiveness of incremental and maximum bite advancement during treatment of Class II Division 1 malocclusion with the Twin-block appliance in the permanent dentition. It was performed at 3 district general hospitals in the United Kingdom with 4 operators. Two hundred three patients, 10-14 years old, were randomized. Control patients had the initial bite taken edge-to-edge for appliance construction with a standard Twin-block. Experimental patients had 2 mm initial bite advancement and subsequent 2 mm advancements at 6 weekly intervals with a Twin-block appliance incorporating advancement screws. Data were collected at the start and the finish of Twin-block treatment. The use of incremental advancement of the Twin-block did not confer any advantages in terms of process and outcome of the treatment. However, patient compliance was influenced by operator and patient age. The duration of treatment was influenced by operator and initial overjet. Incremental bite advancement produced no advantages over maximum advancement.

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    • "Since the variance of the outcome variable was not known, the size of the sample was calculated to identify a difference between the appliance groups of 1 standard deviation (SD). The limitation of this assumption is that if the SD is large, the study will identify only large differences ( Altman, 1991 ). The Statistical Package for the Social Sciences for Windows (SPSS Inc., Chicago, Illinois, USA) was used. "
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