Molar-incisor hypomineralization in a cohort of individuals born with cleft lip and palate.

OBJECTIVE: This study aimed to investigate the frequency of molar-incisor hypomineralization (MIH) in individuals born with cleft lip and or cleft palate. SETTINGS AND SAMPLE: Three hundred eighty-six individuals born with cleft lip and/or palate before orthodontic treatment. METHODS: All the individuals were submitted to a clinical examination and intraoral standardized photos. The registration of MIH was taken by two orthodontists and analysed in association with the cleft type and laterality. The Kruskal-Wallis test and the regression test were used to compare the frequency of molars and incisors affected according to cleft type and laterality, sex and age. RESULTS: We found a frequency of 67.87% of MIH in the studied sample. The frequency varied from 25% (in individuals born with cleft palate) to 77% in individuals born with bilateral cleft lip and palate). The number of affected molars was statistically different depending on cleft type and laterality (P < .001- Kruskal-Wallis test). Differences were found between individuals born with unilateral cleft lip and palate and unilateral cleft lip and alveolus (P = .03), and with isolated cleft palate (P = .03), and between individuals born with bilateral cleft lip and palate and born with unilateral cleft lip and alveolus (P = .01), and cleft palate (P = .01). Sex (P = .21) and age (P = .36) had no influence on the frequency of MIH. A positive correlation was found between the number of molars affected and incisors affected (P < .001). CONCLUSION: Individuals born with cleft lip and palate have a higher frequency of MIH, and the complexity of cleft type was associated with the number of affected molars.