Caries prevalence and molar incisor hypomineralisation (MIH) in children. Is there an association? A systematic review

Aim Molar incisor hypomeralisation (MIH) is a dental condition clinically characterised by the presence of morphological and qualitative enamel defects involving the occlusal and/or incisal third of one or more permanent molars or incisors. Its worldwide prevalence ranges between 2.4 and 40%. Several harmful conditions, such as genetic or medical problems during pregnancy, may act together and increase the risk of MIH. The main objective of this systematic review is to assess whether there is a correlation between MIH and dental caries in mixed or permanent dentition. Methods An electronic search was performed on PubMed (Medline), Scopus and Cochrane Library for articles published from August 2022 to April 2023. Cohort, cross-sectional, retrospective and prospective studies were included. In vitro and animal studies, as well as clinical cases and systematic reviews, were excluded. Studies not differentiating between mixed and permanent dentition were excluded. The observed variables were DMFT (Decayed Missed Filled Teeth) score, DMFS (Decayed Missed Filled Surface) and DMF scores related to FPM (First Permanent Molar) and the clinical prevalence of MIH.Results: After full assessment, 23 articles were selected and included in the qualitative synthesis. Observational cross-sectional studies were evaluated through the AXIS system, while the Newcastle -Ottawa scale was used for cohort studies. The main limitation of this systematic review is that, currently, no RCT on MIH and its correlation with caries have been published. The data source was limited to cohort and cross-sectional studies.Conclusions: DMFT, DMFS and DMFT on FPM scores are significantly different between the group of patients with MIH and the control group. The available evidence supports a correlation between MIH lesions and caries. Caries indexes scores increase proportionally to the severity of MIH.