Aligners show similar occlusal improvement to braces

Dental Tribune International

Mon. 12 October 2026

save

RIYADH, Saudi Arabia: Although aligners can achieve occlusal improvements comparable to those of fixed appliances in selected cases, evidence is less conclusive for more complex malocclusions and long-term stability. A new systematic review by researchers in Saudi Arabia has sought to advance comparisons between the modalities by assessing occlusal improvement, treatment duration and post-treatment stability in studies reporting peer assessment rating (PAR) index scores.

According to the researchers, existing research focuses mainly on the predictability of individual tooth movements rather than overall occlusal outcomes measured using composite indices. The PAR index is a validated method of quantifying the severity of a malocclusion and the degree of improvement achieved through orthodontic treatment. By concentrating specifically on studies that used the PAR index, the researchers sought to provide a more consistent basis for comparing treatment outcomes across the available literature.

The review included seven studies. Five directly compared aligners with fixed appliances, and two provided supporting evidence on the effectiveness of aligner therapy and monitoring strategies.

Across the studies included, aligner therapy produced substantial reductions in PAR scores. The researchers combined the results of three comparative studies assessing percentage reductions in PAR scores and found no significant difference between the modalities. In a separate analysis, they combined the results of three studies that reported the proportions of patients achieving what the PAR index classifies as “great improvement”. This analysis result favoured fixed appliances, but the difference was not statistically significant, and thus researchers emphasised that this did not establish their superiority.

Treatment duration also showed no consistent advantage for either modality. The researchers suggested that treatment efficiency may depend on factors such as malocclusion complexity, extraction protocols, aligner system, staging strategy and clinician expertise rather than appliance type alone.

Evidence on retention outcomes was particularly sparse. Only two non-randomised cohorts contributed stability data, and differences in follow-up periods and retention protocols made comparisons difficult. The authors therefore considered the evidence insufficient to form conclusions about whether either appliance type offers an advantage in maintaining treatment results.

Overall, the analysis did not identify a clear difference between aligners and fixed appliances in occlusal improvement or treatment duration. However, the authors cautioned that the available evidence is too limited and varied to conclude that the two approaches perform equivalently. The researchers emphasised the need for studies that compare aligners with fixed appliances in clearly defined extraction and non-extraction cases, use consistent outcome measures and include longer follow-up periods to assess the stability of treatment results.

The study, titled “Occlusal improvement, treatment duration, and stability with clear aligners: A systematic review and meta-analysis of Peer Assessment Rating (PAR)-based evidence”, was published online on 4 October 2026 in Cureus.