Hypomineralised second primary molars: prevalence, defect characteristics and possible association with Molar Incisor Hypomineralisation in Indian children

To report on the prevalence, defect characteristics, and distribution of hypomineralised second primary molars (HSPM) in Gautam Budh Nagar, Uttar Pradesh, India and to report on possible association, if any, between HSPM and molar-incisor-hypomineralisation (MIH).

A cross-sectional survey included a random sample of 978, 6-8-year-old school children. EAPD diagnostic criteria for scoring MIH defects on first permanent molars (FPM) were adapted and used to score hypomineralisation defects in both FPM and second primary molars (SPM) by a single calibrated examiner. Comparative statistics for HSPM versus hypomineralised FPM were computed using a Chi square test. An odds ratio (OR) at 95 % confidence interval (CI) was used to test and any association between HSPM and MIH.

An overall prevalence of 5.6 % (55/978) was reported for HSPM in the study population. Prevalence of MIH as hypomineralised FPM was 7.4 % (72/978). Concomitant presence of HSPM and MIH was observed in 32.73 % (18/55) of affected subjects. The presence of HSPM had significantly higher odds ratio for development of MIH (OR 7.82; 95 % CI = 4.18-14.65; p < 0.001). A greater severity of defects was observed in HSPM compared with affected FPM as greater number of affected surfaces presented with post-eruptive breakdown (PEB) in former compared to latter (p < 0.001).

The prevalence of HSPM in 6-8-year-old Indian children was 5.6 %. The severity of hypomineralisation was milder in FPM compared to SPM. The presence of HSPM was reported to have significantly higher odds for development of MIH in future.