The aim of this study is to assess the prevalence of MIH among a group of Egyptian children aged from 8-12 years old in Dakahlia governorate schools.

• Clinical examination will be carried out in the school laboratory or an empty class, in day light, teeth will be cleaned gently using gauze and wet with saliva during examination. A disposable diagnostic set (mirror, probe) will be used for each patient where mirrors will be used for proper visualization especially for maxillary teeth. Blunt explorers will be used to aid in tactile sensation if needed, as during the differentiation between rough and smooth enamel edges and/or during the inspection of the caries extent if it exists. No diagnostic radiographs will be taken.
• An examination chart (Appendix 1) will be filled for each child including: date, name, age, address, gender, school, medical health and any previous dental treatment, followed by clinical examination to the four first permanent molars and the eight maxillary and mandibular incisors to detect the presence of MIH and its severity based on European Academy of Pediatric Dentistry (EAPD) criteria . To diagnose Molar Incisor Hypomineralization, at least one affected first permanent molar is required. Extracted first permanent molar will be recorded as affected if another first permanent molar has a defecting MIH
• Each child affected with MIH will be given a letter outlining his dental health status, to inform the parents and indicate the need for treatment.

Examination chart

Date:

Personal information:

Name: Age: Gender:

Address:

School:

Medical history:

Dental history:

Clinical examination:

8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8

8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8

Severity according to EAPD:

Code Description Severity 0 No defect

1. White or creamy demarcated opacities/mild Mild
2. Yellow or brown demarcated opacities Mild
3. a Enamel loss Moderate

3b Enamel and dentin loss Severe 3c Atypical large cavities extended to pulp and covering one or more tubercle Severe 4 Atypical restorations Severe 5 Extracted tooth Severe

Comments:

MIH: presence / absence Severity: Mild / Moderate /Severe

(Appendix 1)

Inclusion Criteria:

• Acceptance for participation in the study.
• Children aged from 8-12 years old.
• Eruption of at four first permanent molars.
• Both genders.

Exclusion Criteria:

• Uncooperative children.
• Children with orthodontic appliances.
• Children with systemic diseases which may affect teeth development.
• Children suffering from any other type of enamel defect as enamel hypoplasia and amelogenesis imperfecta.

Egyptian children aged from 8-12 years old in Dakahlia governorate schools.