Prevalence, pattern and distribution of molar incisor hypomineralization among eight-year- old children in Uasin Gishu County, Kenya

Abstract

Background: Molar incisor hypomineralization (MIH) is a disorder characterised by enamel hypomineralization that affects molars and incisors in the secondary dentition. Its effects start at the amelogenesis stage, manifesting clinically from the age of six when these teeth erupt. The aetiology of (MIH) has been linked to genetic, environmental, and nutritional factors, among others. It is a significant cause of dental morbidity, often leading to the extraction of the first molar, which is a key tooth in the stability of dental occlusion. The pain and sensitivity associated with MIH can disrupt children's lives, and the challenge of achieving local anaesthesia for MIH teeth is well-documented. However, most data on MIH come from other continents, with only a few studies conducted in Africa, particularly in Kenya. Objective: To determine the prevalence and identify the pattern of MIH and its distribution among eight-year-old children attending public primary schools in Uasin Gishu County. Methodology: A descriptive cross-sectional study design was adopted. A multistage sampling technique where three schools per subcounty were sampled, and then twenty-two pupils were randomly selected using a digital sampling frame. A sample size of 396 school-going children, aged 8 years, from public primary schools in Uasin Gishu was included. The European Academy of Pediatric Dentistry validated questionnaire was applied to collect data. Descriptive statistics comprising frequencies, mean and percentages as well as chi-sqaure tests were used to analyze data. Ethical approval from the Institutional Research Ethics Committee (IREC) and the Ministry of Education. Results: 51.8% of the participants were female, while 48.2% were male. The study revealed that 11.9% of the children had MIH. However, no statistically significant difference in occurrence was found between males and females(p=0.918). The first permanent molars were the most frequently affected teeth. Specifically, the lower right first molar (index 46) was the most affected, with 10.9% of children showing hypomineralization. This was closely followed by the lower left first molar (index 36) at 10.6%, the upper right first molar (index 16) at 10.4%, and the upper left first molar (index 26) at 9.6%. Presentations of MIH varied widely among the affected children, with most cases involving demarcated opacities, either with or without post-eruptive breakdown. The least common being dental restorations and missing due to MIH. Conclusion: MIH is a prevalent dental condition with a distinct distribution pattern and varied clinical presentations in Kenya. Despite the high prevalence rates, proactive measures for early detection remain insufficiently implemented. Its clear pattern distinguishes it from other dental conditions, thus facilitating diagnosis. The timing of clinical presentations and the known distribution of MIH are crucial for timely intervention to mitigate the deleterious effects of MIH and for achieving a good prognosis. Recommendation: There is a need to incorporate MIH screening into school health programs and provide further education to dental health practitioners to ensure early detection and management.