Prevalence of Hypomineralized Second Primary Molars and Its Association With Hypomineralized Primary Canines In A Group of Egyptian Children: A Cross-Sectional Study.

Developmental defects of enamel are common among deciduous and permanent dentition. One of these defects is termed molar incisor hypomineralization which refers to a qualitative defect in the enamel due to disruption in the process of calcification and maturation of ameloblasts. The most remarkable clinical appearance of the lesion is the weak quality of enamel which leads to teeth being susceptible to decay .

In 2011 a standardized scoring criteria was introduced by the European Academy of Pediatric Dentistry for proper diagnosis of MIH. Moreover, to distinguish MIH from other developmental enamel defects. Due to the poor quality of enamel, patients with MIH are prone to several challenges like hypersensitivity, dental pain and post eruptive enamel breakdown which creates drawbacks for the dentist to properly manage the case

A study conducted in 2013 referred to MIH occurring in primary dentition and was primarily termed as deciduous molar hypomineralization (DMH). Teeth was recorded using EAPD diagnostic criteria and the prevalence of DMH was 4% in teeth examined in a sample of 6,487 participating children. In addition, they found that the occurrence of MIH in children affected with HSPM was of higher results. Furthermore, children with more than one affected molar represented severe form of HSPM.

Another study conducted on Iraqi children to detect the prevalence and severity of HSPM on a sample of 809 children aging 7-9 years showed 6.6%. By using the EAPD scoring criteria and International Caries Detection and Assessment System the study revealed that more severe form of caries was proportional with the amount of demarcated lesion, moreover 39.6% of the cases examined showed correlation between HSPM and MIH.

The American Academy of Pediatric Dentistry in 2017 published a study that detected the prevalence of HSPM and HPC in a group of 1963 schoolchildren, the results were 6.48% and 2.22% respectively by adapting the EAPD scoring criteria and the Caries Assessment Spectrum and Treatment. Considering the severity, 70% of the affected cases reported mild to moderate hypomineralization. Furthermore, the study reported children diagnosed with HSPM or HPC are six times more likely to develop MIH.