Method: Prospective cross-sectional descriptive study on children seeking for dental attention at the Department of Comprehensive Children’s Dentistry (A: University Public Hospital), in 2 pediatric private offices of the members of the team (B: Private sector) and in 2 schools of high social risk (C: No demand for dental care) all of them located in the City of Buenos Aires between April and August 2011 (Kappa 0.92 0.89-0.97). The study included all the children born between 1998-2003, whose 4 first molars and 8 permanent incisors had erupted. The teeth were clinically evaluated and specially designed charts were used to record sex, year of birth, type of access to dental care, presence of MIH and number of affected incisors and molars. Percentages, Chi Square and Fisher exact Test were used for the analysis of the data.
Result: 1109 children 10.57 years±1.56 were evaluated (48.95% male). Prevalence of MIH was 21.73% (19.33-24.28), with 70.85% (67.86-73.71) of molars and 52.15% (49.33-54.95) of incisors affected. Distribution according to the year of birth showed the lower values in 1998 (12.80%) and highest in 2003 (32.20%) (p<0.001). Group A was composed of 311 children, B of 564 and C of 234, 10.52±1,54, 10.51±1.52 and 10.71±1.53 years respectively (p=0.22). Prevalence of MIH was 8.03% (5.26-11.64) in A, 27.78% (24.16-31.74) in B and 25.21% (19.76-31.3) in C. (p<0.001).
Conclusion: In this sample MIH showed to be a prevalent pathology regardless of the type of dental health care registering the highest values among children born in the last year of the population under study