Evaluation of effectiveness and stability of aligner treatments using the Peer Assessment Rating Index

Aims The aims of this study were to measure treatment effects of aligner treatments in adult patients directly after treatment and the stability of these effects after a short-term retention period using the Peer Assessment Rating (PAR) Index. Methods This double-center trial consecutively screened 98 adult patients of whom 33 patients were treated according to predefined inclusion and exclusion criteria. The study sample was shown to be representative for adult orthodontic reality with regard to gender, age, and distribution of malocclusion type. Malocclusion severity was rated by using the PAR Index measured at baseline (T0), after finishing orthodontic treatment with Invisalign® (T1; Align Technology Inc., Santa Clara, CA, USA) and after a mean retention period of 10 months (T2). Furthermore, to better understand the observed treatment modality, specific treatment characteristics were recorded and analyzed. Results The average PAR score at T0 was 22.18 (standard deviation [SD] ± 8.68). Posttreatment PAR score was 4.64 (SD ± 4.23) at T1 and was stable after a retention period of 10.07 months at T2 (SD ± 126.80 days; PAR 4.36, SD ± 3.93). All of the study cases showed a significant reduction of the total PAR score between T0 and T1 ( p