Assessment of Orthodontic Treatment Results and Comparison between Fixed Lingual and Labial Appliances

Abstract

Interest in objective assessment of orthodontic treatment outcomes and in quality control of orthodontic treatment is increasing. In recent years, the evaluation of orthodontic treatment results has been carried out with the help of various indices or different rating systems. No published studies have used the ABO Objective Grading System for evaluation of orthodontic treatment outcomes for all cases in the clinical series. There are also very few studies, conducted mainly in Europe, that have assessed treatment results in postgraduate orthodontic clinics. There is one known study comparing treatment results between fixed lingual and labial appliances. The objectives of the present study were: first, to assess treatment outcomes in the IUSD Graduate Orthodontic Clinic for three years (1998, 1999, and 2000); and second, to compare treatment results achieved with the use of fixed lingual and labial appliances. Pre and posttreatment records (study casts, panoramic and lateral cephalometric radiographs, and extraoral and intraoral photographs) of 521 patients treated in the IUSD Graduate Orthodontic Clinic were evaluated. Treatment outcomes were assessed for a 3-year period using the ABO Grading System and IUSD Comprehensive Clinical Assessment Criteria. Statistically significant differences were found for the majority of the evaluation criteria between the selected three years. The overall quality of finished cases decreased from 1998 to 2000. This trend may reflect preferential finishing of the cases that were going well and transferring all the other cases. No assumptions regarding the overall performance of the Clinic should be made based on the results of this study. It should be remembered that these three years were selected for a particular reason. In the fall of 1997, a clinical grading program was initiated. All active cases (1997-98 academic year) were to be finished within three years. The year 2000 was the deadline to finish all active long treatment time cases. Most of the cases that were in treatment for a long time were progressing poorly and were not finally finished until 2000. This group of difficult cases contributed to the decreased quality of the finished cases and longer treatment time during the year 2000 compared to 1998 and 1999. It is anticipated that treatment outcomes will improve in 2001 since the backlog o flong treatment time cases has been cleared. The evaluation of this three-year period (1998-2000) was the baseline evaluation for comparison of finished cases for subsequent years. When comparing treatment results between fixed lingual and labial appliances, significant differences were found for only 4 of 24 parameters. These outcome differences were, mainly, due to the inherent characteristics of the lingual appliance rather than to the treatment approach of the supervising instructor. Even though statistically significant differences were found for a few parameters between two types of appliances, they did not indicate the advantages of one appliance over the other. The present study suggests that the treatment results can be as good with lingual as with labial appliances. This study also has established a baseline for comparison of clinical outcomes in the IUSD Orthodontic Clinic for subsequent years.