Predictive Value of Hypomineralization of Second Primary Molars for Molar Incisor Hypomineralization and Other Relationships between Both Developmental Defects of Dental Enamel

Molar incisor hypomineralization (MIH) and hypomineralized second primary molars (HSPM) are dental enamel developmental defects with significant prevalence and psychophysical impact, posing a public health concern. We examined the relationship between HSPM and MIH in 426 children aged 7 to 10 years (213 with MIH, 213 without MIH). The frequency of HSPM was higher in children with MIH (37.1% vs. 11.3%, p < 0.001). However, there was no correlation between MIH severity and presence of HSPM (p = 0.296). In patients with both defects (n = 79), 90% of severe MIH cases were associated with severe HSPM, while 87.8% of mild MIH cases were associated with mild HSPM (p < 0.001). The involvement of permanent incisors by MIH was not influenced by the presence of HSPM or HSPM severity. HSPM exhibited a positive predictive value of 76.7, negative predictive value of 58.8, sensitivity of 37.1% (95% CI = 30.6-43.6%), and specificity of 88.7% (95% CI = 84.5-93%). The odds ratio for MIH based on HSPM was 4.64 (95% CI). HSPM may serve as a predictor of MIH, but its absence does not rule out the occurrence of MIH. The results highlight the need for surveillance programs in children presenting with HSPM to facilitate early diagnosis and preventive measures for MIH-related complications.