Lin, Eric (2020-03). Comparison of Finished Case Quality Between Invisalign vs. Traditional Fixed Appliances - A Randomized Control Trial. Master's Thesis.
Thesis
The purpose of this study was to compare treatment outcomes between Invisalign and traditional fixed appliances using the Discrepancy Index and the ABO Objective Grading System, both at debond and 6 month retention. This randomized controlled trial included 80 patients, recruited from the Texas A&M College of Dentistry orthodontic clinic, who were randomly assigned to either the aligner or the braces group. Three time points were examined: initial (T0), debond (T1), and 6 month retention (T2). At T1, there were 66 total patients, 32 aligner and 34 braces patients. The median age of aligner patients was 26.7 (IQR 9.8) and median age of braces patients was 25.9 (IQR 16.6). At T2 there were a total of 54 patients, 26 aligner and 28 braces patients. Subjects were analyzed at T0 using the ABO Discrepancy Index (DI score) , and at T1 and T2 using the ABO Objective Grading System (ABO-OGS score). All patients were treated by one ABO certified orthodontist and all measurements were completed by one examiner. The median DI score for the aligner group was 4.5 and for the braces group was 7.0 (p=0.015), a statistically significant but clinically insignificant difference. At debond, there were no significant between group differences for total score (p=0.158) or any of the individual categories. At 6 month retention, there were also no significant between group differences for total score (p=0.367) or any of the individual categories. From debond to 6 month retention, the aligner group showed no significant changes in total score (p=0.314), and the braces group also showed no significant difference in total score (p=0.169). From T1 to T2, there were also no between group differences in score change between the aligner and brace group (p=0.677). The braces group finished 0.4 years, or 4.8 months faster than the aligner group, a difference that was significant (p<0.0001). For simple orthodontic cases, is faster and more cost effective to treat with traditional fixed appliances over clear aligners.
