Excellent versus unacceptable orthodontic results: influencing factors

To retrospectively compare patients with excellent and unacceptable orthodontic treatment results with respect to possible prognostic factors.

All patients, who completed treatment at the Department of Orthodontics of the Justus-Liebig-University Giessen, Germany between 1993 and 2009 with an excellent or unacceptable outcome according to the Ahlgren index. Possibly influencing factors regarding case history, treatment, cephalometrics, and plaster casts were analyzed. Furthermore, PAR index pre- and post-treatment was compared. The explorative statistical analysis was performed using Fishers Exact test, Chi-square test, and Mann-Whitney U-test.

Out of 1653 patients, treatment outcome was excellent in 226 (13.7 per cent) and inacceptable in 56 (3.4 per cent) patients. For the remaining cases, a good or acceptable outcome was assessed. Pretreatment PAR scores showed no difference between the excellent and unacceptable group. The following factors were significantly more common in the unacceptable group: male predominance (P = 0.009), occurrence of general diseases (P = 0.003), habits (P < 0.001), prolonged active appliance treatment duration (P = 0.014), negative cooperation (P < 0.001), denial of recommended appliance or premature removal of appliances (P < 0.001), decreased pretreatment overbite (P = 0.005), and hyperdivergent jaw base relationships (P = 0.005).

Patient cooperation remains the outstanding parameter determining treatment success. A proportionally higher frequency of unacceptable treatment results must be expected in patients with open bite configurations (skeletally, dentally, and functionally).