Prevalence of malocclusion in the Polish population estimated by systematic review and meta-analysis

Estimates of malocclusion prevalence in Poland are derived from heterogeneous studies that differ in source population, recruitment, age and diagnostic criteria. This review synthesised the available evidence while explicitly addressing representativeness, sample dependence and outcome-definition heterogeneity. PubMed, Google Scholar, Polska Platforma Medyczna and Polska Bibliografia Lekarska were searched from inception to 9 March 2025 and updated on 9 August 2026. Eligible observational studies reported malocclusion or specific occlusal traits in populations studied in Poland. Source population, recruitment setting and diagnostic approach were extracted. Risk of bias was assessed by domain using the JBI checklist for prevalence studies. The primary synthesis was restricted to population-oriented samples and conservatively excluded potentially overlapping cohorts. Random-effects meta-analyses used logit-transformed proportions, restricted maximum-likelihood estimation of between-study variance and Hartung–Knapp confidence intervals; 95% prediction intervals were reported. Fifty-two publications contributed 62 dataset-level rows; 57 datasets reported a single overall-malocclusion prevalence before dependence exclusions. The primary population-oriented synthesis included 42 dataset estimates (summed denominator 61,894) and yielded a pooled prevalence of 60.5% (95% CI 55.3–65.6%), with extreme heterogeneity (I 2 =97.2%) and a wide 95% prediction interval (28.1–85.8%). The all-eligible analysis was similar (59.9%, 95% CI 55.6–63.9%). In the primary synthesis, Class II malocclusion was 34.4%, Class III 3.4%, deep bite 11.6%, open bite 5.2%, crossbite 12.9% and crowding 34.6%; heterogeneity remained substantial for most outcomes. Recorded occlusal deviations are common in populations studied in Poland, but the available literature does not support a precise estimate of national prevalence. Although the overall distribution of malocclusion types appears broadly comparable with that reported in other European populations, wide prediction intervals, heterogeneous definitions, and the use of non-probability sampling limit comparability and generalisability. PROSPERO CRD42023462671.