Aim of the study: This study aims to detect the prevalence of hypomineralized second primary molars and its association with hypomineralized primary canines in a group of Egyptian children. Furthermore, it also addresses the possible etiological factors that might predispose hypomineralization of deciduous teeth.

Rationale:

This study tends to fill the knowledge gap about the prevalence of hypomineralized second primary molars as well as its association with hypomineralized primary canines in a group of Egyptian children. In addition to identifying the possible predisposing etiological factors.

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.

Another study was implemented in 2021 to detect prevalence of HSPM/HPC and to mark out the lesion characteristics, location and severity. Guided by the EAPD scoring criteria the results are as follows, in a sample of 153 patients HSPM showed 18.95% and HPC showed 11.11%. The lesions were mostly detected on the buccal and occlusal surfaces. This study measured the severity in 153 samples to report majority of lesions exhibiting mild degree severity.

A study that was conducted in North India to detect the prevalence of HSPM showed 7.9% in a sample of 300 patients. In addition to determining the possible etiological factors behind the occurrence of HSPM. The etiology remains uncertain, however based on the data collected from medical reports and from the parents, the study concluded that prenatal and post-natal factors showed higher prevalence of HSPM than perinatal factors.

Inclusion Criteria:

• Children aged 4-9 years.
• Cooperative patients.
• Medically Free children.
• Both Genders; females and males will be included.

Exclusion Criteria:

• Non-Egyptian nationality.
• Special Health Care Needs Patients.
• Other developmental enamel defects (Non-MIH/HSPM); Amelogenesis Imperfecta, dental fluorosis and hypoplasia.
• Other medical syndromes.

Children attending Outpatient clinics of Cairo University will be recruited in the study.