Intellectual disabled persons faced more dental problems. According to a medical review paper of international and local studies, this group has poorer dental hygiene, more severe gum disease and more untreated caries. In 2010, a report from the guardians in Hong Kong mentioned that most adults with intellectual disability cannot clean their teeth, the have dental problems and it is very difficult for intellectually disabled students to co-operate during the dental treatment. In order to alleviate their dental problems, supervised toothbrushing programme and an oral health education talk are proposed. The investigators investigate the effectiveness of the supervised toothbrushing programme and an oral health education talk. The target group of the study is mild to moderate grade intellectual disabled students of special schools in Hong Kong. A clustered randomised controlled trial design is adopted.

Intellectual disabled persons faced more dental problems. According to a medical review paper of international and local studies, this group has poorer dental hygiene, more severe gum disease and more untreated caries. In 2010, a report from the guardians in Hong Kong mentioned that most adults with intellectual disability cannot clean their teeth, the have dental problems and it is very difficult for intellectually disabled students to co-operate during the dental treatment. In order to alleviate their dental problems, supervised toothbrushing programme and an oral health education talk are proposed. The investigators investigate the effectiveness of the supervised toothbrushing programme and an oral health education talk. The target group of the study is mild to moderate grade intellectual disabled students of special schools in Hong Kong. A clustered randomised controlled trial design is adopted.

Inclusion Criteria:

• Mild and moderate grade intellectual disabled students in special schools.

Exclusion Criteria:

• 1. Those students who have simultaneously joined other oral health programme during the study period.
• 2. Those students with the presence of conditions rendering a need of antibiotic prophylaxis prior to periodontal examination e.g. rheumatic heart disease.
• 3. Uncooperative students that oral examination is not possible.

data entered by independent clerical staff with no information of the detail of the study outcomes assessor will not be told which group of subjects are examined but there is a chance that the subjects tell him/her