The aim of the study is to compare application of sealants together with fluoride varnishes versus only fluoride varnishes in preventing caries lesions development in the occlusal surface of first permanent molars of children with ASDs.

The aim of the study is to evaluate if the application of pit and fissure sealants together with fluoride varnishes is more effective than the application of the only fluoride varnishes in preventing caries lesions development in the occlusal surface of first permanent molars of children with ASDs.

Patients with at least 10-year follow-up and ASDs are recruited and allocated to two cohort according to the strategy adopted for prevention of caries in first permanent molars: FA group (only fluoride varnishes) and FA+S group (sealants together with fluoride varnishes).

Caries incidence and sealants retention after the follow-up period are recorded. Demographic and clinical characteristics of patients at first dental visit are also recorded (age, level of cooperation, presence of systemic diseases other than ASDs, caries severity) to evaluate if they play a potential protective and/or risk factors for caries development.

Logistic and multivariate analysis are run to evaluate caries incidence and retention rate of sealants in first permanent molars over a period of at least 10 years.

Inclusion Criteria:

• ASDs
• age less than 14 years
• written declaration of informed consent signed by parents/guardians

Exclusion Criteria:

• incomplete clinical records
• missing five or more dental check-ups over the follow-up period
• oral or dental care provided in sedation or general anesthesia
• follow-up less than 15 years

Primary care clinic: participants were enrolled among those who have being received dental care at the Dental Service for ASD children of San Paolo Hospital, Milan, Italy.

Data will be available upon request