Prevalence of the Cusp of Carabelli: a systematic review and meta-analysis.

Context: The Cusp of Carabelli (CoC) is the most commonly occurring dental morphological trait.

Objective: To provide a pancontinental overview on the prevalence of the CoC in primary maxillary second molars and permanent maxillary molars.

Methods: An electronic search was conducted on ten databases without year restrictions up to July 2020. All cross-sectional studies published in the English language reporting prevalence estimate of CoC were included. A modified version of the Newcastle-Ottawa scale was used to assess study quality. Meta-analyses were conducted for studies that reported data using Dahlberg and ASUDAS classification across continents.

Results: For qualitative synthesis, 142 studies (45,327 participants) were included, of which 130 studies had moderate risk of bias. Random effects meta-analysis was performed for 41 studies. For prevalence of CoC in primary maxillary second molars, the estimate was 72% (2,829 participants). The overall percentage attained for permanent maxillary molars was 59% (16,607 participants) for first molars; 8% (2,277 participants) for second molars; and 10% (89 participants) for third molars. Subgroup analysis revealed the European continent reported the highest prevalence in permanent maxillary first and second molars.

Conclusion: Primary maxillary second molars recorded highest prevalence of CoC followed by permanent maxillary first, third and second molars. Pancontinental studies with regard to primary maxillary second molars are warranted.