Influence of the duration of orthodontic treatment on the subjective perception of oral health-related quality of life

Background Due to currently limited amount of data, the aim of this observational, prospective study was to examine the impact of the duration of orthodontic treatment on oral health-related quality of life (OHRQoL) in patients. Method Data was collected using the German basic version of the Oral Health Impact Profile (OHIP-G14) from 2008 to 2018. OHRQoL was conducted at three different points in time with 598 patients during their orthodontic treatment. The results were statistically analyzed. Results 79 out of 598 patients included initially completed the questionnaires completely and could be included in the study. A comparison of the appointed subgroups (gender, age groups, treatment apparatus and treatment period) with one another did not reveal any significant differences in any of the groups (Mann-Whitney U test, Kruskal-Wallis test, p < 0,05). A clinically relevant increase in the OHIP-G14 total value and thus a decrease in OHRQoL could be determined applying the Minimal Important Difference (MID & GE;2,00) during the initial treatment phase. These findings were also statistically relevant (Friedmann test, p < 0,05). An improvement in OHRQoL at the end of treatment was statistically significant (p < 0,05), though not clinically significant (MID < 2,00). A negative influence of the duration of treatment on OHRQoL could not be confirmed at any time (beta (Z) =- 0.078, beta (E) =0.191, multiple linear regression). Conclusion During the initial treatment phase, OHRQoL appears to be slightly reduced, the average of the total values measured ranged within the standard values of the general population. Since the duration of treatment does not have a significant impact on OHRQoL, striving for a good treatment result in the context of a differentiated orthodontic therapy should, if possible, be chosen over a rapid completion of treatment.