PREVALENCE OF MOLAR INCISOR HYPOMINERLIZATION AMONG A GROUP OF EGYPTIAN CHILDREN: A CROSS SECTIONAL STUDY

Objective: This study aimed to determine the prevalence of molar incisor hypomineralization (MIH) among a group of Egyptian children aged 8-12 years old in Giza Governorate. Material and methods: This study was conducted in Al-Ayat in Mounira Farghally and Aldenaweya schools in Giza, Egypt. The sample size was 371 students.All the students aged 8-12 years who attended school on the day of examination were examined for the presence or absence of MIH. MIH was recorded when at least one of the first permanent molars shows any of the diagnostic criteria of MIH according to the modified index developed in line with European Academy of Paediatric Dentistry criteria. Results: The gender distribution among the participants was 191 boys (51.5%) and 180 girls (48.5%). The mean (SD) values for age were 10.1 (±1.4) years with a minimum of 8 and a maximum of 12 years old. MIH was found in 10 children giving a prevalence of 2.7% among the examined children. The majority of the children (70%) diagnosed with MIH presented lesions in both permanent first molars and incisors with different degrees, and 30% of them presented lesions in permanent first molars only. Conclusions: The prevalence of MIH among the study sample was 2.7%. The most prevalent defect reported in this study was demarcated opacity. The most common degree of severity of MIH in the studied population was the mild degree. (30) Aya Refaat Abd El Ghaffar, et al. E.D. J. Vol. 68, No. 1 MIH is a developmental, qualitative enamel defect caused by reduced mineralization and inorganic enamel components that ends up in enamel discoloration and fractures of the affected teeth. Initially, the condition was termed as affecting the first permanent molars and incisors but more recently it has been noted that these defects could affect any primary or permanent tooth (Almuallem and Busuttil-Naudi, 2018). The causative mechanism of MIH remains unclear, but the clinical presentation of localized and asymmetrical lesions suggests a systemic origin with the disturbance during the amelogenesis process most likely occurring within the early maturation stage or even earlier at the late secretory phase (Weerheijm, 2004 and Saber et al., 2018) MIH increases dental caries risk of affected teeth because teeth not only have soft and porous enamel but are also very sensitive to stimuli making effective oral hygiene difficult.Clinicians face significant challenges with MIH, with the contemporary approaches to its restorative treatment remaining relatively ineffective (Crombie et al., 2009). The available data regarding MIH prevalence from studies performed within the Middle East is deficient relative to the data from the studies performed in Western Europe. Therefore, this study aimed to assess the prevalence of MIH among a group of Egyptian children aged from 8 to 12 years in Giza Governorate. MATERIALS AND METHODS Sample Size Calculation The sample size was calculated to determine the minimum proper sample size for the prevalence of molar incisor hypomineralization among Egyptian children in Giza governorate. Reviewing the literature revealed that the prevalence in similar situations ranged from 0.48% to 40.7% with an average of 20%. Assuming that the true prevalence may change ± 5%, it is needed to survey 371 children to be able to achieve 80% power, setting the alpha error to 0.05 and the margin of error at 5 % the sample became 371. Sample size calculation was done using StatCalc, Epi Info version 7 for MS Windows, Centers for Disease Control and Prevention (CDC), USA . (Al-Hammad t al., 2018).