First Permanent Molars and Permanent Incisors Teeth by Tooth Prevalence of Molar–Incisor–Hypomineralisation in a Group of Spanish Schoolchildren

BACKGROUND: Molar-incisor-hypomineralisation (MIH) is a disturbance in dental development that commonly involves first permanent molars but permanent incisors may also be compromised. The prevalence of MIH in the literature varies between 2.5% and 40% of the world child population. Little information is gained on the prevalence of MIH among children in Spain. AIM: The aim of this study was to investigate the prevalence of MIH among school children from Barcelona, Spain. MATERIAL AND METHODS: A cross-sectional study which included 705 children, aged 6 -14 years and 11 months was carried out. Full mouth examinations were performed using the European Academy of Paediatric Dentistry (EAPD) criteria for the diagnosis of MIH. RESULTS: A total of 56 cases of MIH were found, 22 (39.3%) boys and 34 (60.7%) girls. The prevalence was 7.94% (6.39% for boys and 9.41% for girls). MIH lesions were seen more often in girls than boys (χ(2) = 4.9, p= 0.023) the male/female ratio being 1:1.54. Upper teeth were more prevalent than lower teeth in both genders with an upper/lower ratio of 1.86/1 for boys and 1.68/1 for girls. CONCLUSION: Considered either by gender or by teeth, upper teeth and girls were ahead in our sample.