Collections > Electronic Theses and Dissertations > A Contemporary Perspective on Tooth Extraction in Orthodontics

Introduction: The decision to extract teeth for orthodontic purposes is one of the most complex and debated topics in the specialty. The profession's understanding of factors affecting the extraction decision (e.g., outcome stability and facial appearance) has evolved over time, and estimated extraction rates have varied from 10% in 1953 to 78% in 1968 to 28% in 1994. A contemporary perspective on the rate of orthodontic extractions is needed to help clinicians understand this treatment choice in light of 21st century philosophies, techniques, and appliances. To this end, we investigated changes in orthodontic extraction rates at the University of North Carolina from 2000 to 2011, as well as factors that may have affected those rates. We hypothesize that extraction rates have changed as a result of evolving diagnostic methodology and appliance selection (e.g., self-ligating brackets). Methods: Pre- and post- treatment records were analyzed to determine extraction rates over time, and different factors (Angle classification, skeletal relationship, use of self-ligation, etc.) were investigated to evaluate potential impact on the extraction decision. The sample consisted of 2,184 patients, with 1,263 females (58%). Age at the start of treatment ranged from 7 to 67 years. Third molar extractions were excluded from analyses. Student t-test and chi square were used to evaluate the extraction rate over time. Logistic regression was used to investigate diagnostic and treatment factors that might affect extraction rates over time. Results: The extraction rate decreased significantly from 2000 to 2005, from 40% to less than 20%. After 2005, it remained stable around 27%. 8 out of our 13 explanatory variables were found to influence the overall extraction rate but none of them could explain the decrease of the extraction rate over time. Conclusions: The extraction rate fluctuated greatly since 2000 and has decreased linearly over the years (p<0.05). Several explanatory variables were found to influence the overall extraction decision, but none of them could explain the decreasing trend over time. Irrational cognition with medical concerns about extraction may have an impact on the decreased trend.