The investigators aim at creating a dedicated pathway to allow accessibility to dental care for ASD children within a hospital Dentistry Department, in order to diminish the need for general anesthesia. Visual pedagogy, parent training, a strict schedule for appointments (every two months) spanning over three years and longer duration of dedicated examination are set up for a group of ASD children, whose behavior is compared to that of children seen one or twice a year.

Treated group:

Enrollment: caregivers receive instructions and a visual pedagogy aid with instructions for toothbrushing. They complete also enrollment and informed consent forms.

At the first visit: caregivers receive a dental mirror to be used at home. Children are free to explore the office and dental room.

Subsequent visits, every two months for three years: trials are made to establish contact with children, make them seat at the dentist's chair, execute dental visits and treatments as needed.

Control group: subjects (similar inclusion and exclusion criteria) that access the Department for clinical reasons or control visits, but cannot comply with the strict two-months schedule.

Inclusion Criteria:

• Age: 4 to 13 years old at the beginning of the treatment,
• Diagnosis: formally diagnosed by a Neuro-psychiatrist and recognized by authorities (for school support) as having Autistic Spectrum Disorder (ASD), possibly also in the frame of genetic syndromes, or Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), a diagnosis present in DSM 4 and merged to ASD in DSM 5.

Exclusion Criteria:

• Age outside the selected range
• additional diseases, preventing autonomous oral hygiene (e.g., motor diseases),
• for the Treated Group: familiarity with dental treatments (possible one or few visits in the past, but not on a regular base)

Only anonymized data, including age, sex, diagnosis and the collected measurements, will be made available to other researchers. Individual Participant data that allow identification of the single participant cannot be shared, as requested by the Ethical Committee.

No masking is possible because caregivers must accept and comply a strict schedule of visits for three years. The dentists are aware of the participation to the protocol because they use additional supports and strategies, like a longer duration of the visit.