Hypomineralised Second Primary Molars (HSPM): Prevalence, Clinical Characteristics and Association with Molar Incisor Hypomineralisation (MIH) in Children in Jordan.

Aim: The purpose of this study was to determine the prevalence of HSPM, its clinical presentation and any association to MIH in Jordanian children.

Materials: A cross-sectional study involving six- to-eight-year-old schoolchildren was carried out by two calibrated examiners. The MIH/HSPM index was used for scoring defects. A self-administered questionnaires exploring pre-, peri-, and post-natal relevant histories were also completed by parents. Descriptive statistics and chi-square test were used for data analysis with a p set at 0.05.

Results: A total of 783 children (417 males and 366 females) with a mean age of (7.27 ± 0.6) years were enrolled in the study. The prevalence reported for MIH and HSPM was 40.1% and 44% respectively. Gender had no influence on the prevalence of HSPM (p=0.28), however, for MIH, the condition was more significantly reported in females compared to males (53.5% vs. 46.5%, p =0.002). The lower molars were significantly more affected than upper molars. Demarcated opacities were the most common clinical presentation. Mild lesion severity was the most frequently reported for both MIH and HSPM. The two conditions were significantly associated with each other (p =0.00,). However, HSPM was not predictive of MIH (OR=1.17, 95% CI=0.95 to 1.44). Regarding potential etiological/ risk factors, maternal intake of vitamin D during pregnancy was significantly associated with less MIH in their children.

Conclusion: MIH and HSPM were quite prevalent in Jordanian schoolchildren. The two conditions were significantly associated with each other, but HSPM was not predictive of MIH.