Prevalence of Periapical Radiolucency and Root Canal Treatment: A Systematic Review of Cross-sectional Studies

IntroductionCross-sectional studies describe the health status of a population and measure the prevalence of disease or treatment. Neither the prevalence of periapical radiolucency, a surrogate for disease, nor the prevalence of root canal treatment have been subjected to a systematic review, which is the highest level of clinical evidence. The purpose of this study was to conduct a systematic review and meta-analysis of the prevalence of periapical radiolucency and nonsurgical root canal treatment.MethodsInclusion/exclusion criteria were used for defined searches in MEDLINE and EMBASE. Title lists were scanned and abstracts were read to determine utility. Articles meeting the inclusion/exclusion criteria were analyzed for heterogeneity. Weighted mean percentages were calculated for the prevalence of overall periapical radiolucency, root canal treatment, and apical radiolucency in both treated and untreated teeth.ResultsDefined searching produced 11,491 titles. Thirty-three articles were included. Most patient samples represented modern populations from countries with high or very high human development indices. Meta-analysis was performed on 300,861 teeth. Of these, 5% had periapical radiolucencies, and 10% were endodontically treated. Of the 28,881 endodontically treated teeth, 36% had periapical radiolucencies; however, cross-sectional studies cannot distinguish between healing and failing cases. Of the 271,980 untreated teeth, 2% had periapical radiolucencies. The technical quality of root canal treatment was decried by most authors of the included studies.ConclusionsThe prevalence of periapical radiolucency was very high, broadly equivalent to 1 radiolucency per patient. The prevalence of teeth with root canal treatment was very high, broadly equivalent to 2 treatments per patient. Billions of teeth are retained through root canal treatment.