Meta-Analysis of Observational Studies on the Most Commonly Missing Permanent Dentition (Excluding the Third Molars) in Non-Syndromic Dental Patients or Randomly-Selected Subjects, and the Factors Affecting the Observed Rates

Abstract

Purpose: The aim of this study was to summarize the literature on the most frequently missing permanent teeth excluding the third molars. Study design: A search was conducted to find all the available literature (in various scientific and general databases) regarding the most commonly missing teeth with respect to ethnicity and time, as well as factors biasing this outcome. Quality assessment was done to exclude studies with inconsistent information, poor designs, or data pertaining to syndromic cases or the third molars. The role of biasing factors was as well quantitatively assessed using statistical analyses [Q-test, Egger regression, Spearman correlation coefficient, multiple linear regression, Welch t-test] (α=0.05). Results: A total of 81 reports was included. The meta-sample was heterogeneous (P=0.000, Q-test). No significant publication bias was detected (P>0.1, Egger regression). The mandibular second premolar was reported as the most commonly missing tooth in most studies, followed by the maxillary lateral (the most commonly missing in the rest). In terms of the missing share of each tooth percent of all missing teeth, the mandibular second premolar and incisors are more likely to be absent, followed by the maxillary second premolar and lateral. The absence of different teeth can be affected by the ethnicity, sample types (epidemiological or dental patients), sample sizes (only in the case of bimaxillary second premolars), and the minimum ages of pooled subjects (only in the case of the maxillary lateral and the mandibular second premolar). Conclusions: Since enrolling younger patients can bias the results, older patients should be sampled.