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Am J Orthod Dentofacial Orthop. 1990 Jan;97(1):45-51.

The duration of orthodontic treatment with and without extractions: a pilot study of five selected practices.

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Department of Orthodontics, University of Michigan, Ann Arbor.


Contemporary orthodontic practice is diverse, both in the variety of clinical problems treated and in the methods used. Practices differ with respect to their patient composition as well as in many variables relative to treatment protocols. Such heterogeneity makes it difficult to make valid generalizations concerning the characteristics of orthodontic treatment procedures or outcomes; yet data and methods are required for assessment of issues of efficacy and utility. The frequency of orthodontic extractions is an objective criterion that distinguishes practices and may also be related to differences in treatment outcome variables, such as duration. Following a telephone survey to estimate extraction rates in the practices of 238 Michigan orthodontists, five practices with very high or low reported rates were chosen for this pilot study. Our primary aim was to determine whether a systematic relationship existed between the relative frequency of extraction treatments and the duration of active appliance therapy. Records of 438 patients from these practices were examined. The extraction rates of the practices ranged from a low of 25% to a high of 84%. Treatment duration was affected by several variables, such as the number of arches treated, the number of treatment phases, and the practice selected. When the data for all five practices were pooled, and all of the extraction versus nonextraction treatments were compared, the mean durations of treatment were 31.2 and 31.3 months, respectively. Data from individual practices, however, indicated that extraction treatment in each of the practices was of longer duration than nonextraction therapy. These differences in duration were 3.0, 6.6, 2.4, 3.0, and 7.3 months in the five practices.(ABSTRACT TRUNCATED AT 250 WORDS).

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