In this prospective randomized clinical trial, the is aim to compare the clinical and radiographic success of 3 minimally invasive treatment protocols on permanent first molars affected with MIH over 24 months. A total of 73children/120molar teeth (N=40 molars per group) between the ages of 6-16 years with MIH will be recruited at the post-graduate clinics at Jordan University of Science and Technology (JUST).

Background: The term molar-incisor hypomineralization (MIH) is defined as 'hypomineralization of systemic origin, presenting as demarcated, qualitative defects of enamel of one to four first permanent molars (FPMs) frequently associated with affected incisors. There are no clinical studies on use of minimally invasive techniques as restorative treatments for molars affected by MIH.

Aim: The aim of this clinical trial is to compare the clinical and radiographic success of 3 minimally invasive treatment protocols on permanent first molars affected with MIH over 24 months.

Methods: A total of 73 children/120 molar teeth (N=40 molars per group) between the ages of 6-16 years with MIH will be recruited for this prospective randomized clinical trial in the post-graduate clinics at JUST. Clinical and radiographic examination will be done. Participants will be randomly allocated to one of the three treatment modalities: For groups 1 and 2, silver diamine fluoride (SDF) will be clinically applied using cotton roll isolation on the first visit for three minutes after cleaning the tooth with gauze. After 1 week, the carious lesion will be examined for signs of caries arrest using two criteria: the color turning darker black and increased hardness of the lesion rather than soft texture (assessed using an excavator), if the criteria are met, the tooth will be restored with high viscosity glass ionomer (HVGIC) and stainless steel crown (SSC) for group 1, or only with a SCC for group 2. If not met, the carious lesion will be assumed to be still active, and a reapplication of SDF will be done before restoring the tooth with HVGIC and SCC. In group 3, the tooth will be restored in a similar fashion to atraumatic restorative treatment (ART technique) and restored with HVGIC and a SCC. Follow up will be done for all groups at 3 months, 6 months, 12 months, and 24 months to record specified clinical and radiographic criteria as outcome measures of success.

Inclusion Criteria:

• Permanent molars with MIH with the following MIH indices (2a, 2b, 3, 4a, 4b) affected by caries (ICDAS 3 or 4) or post eruptive breakdown.
• Restorable teeth
• Permanent molars with MIH with NO clinical/radiographic signs and symptoms of irreversible pulpitis or pulpal necrosis.
• Clear band of dentine radiographically between the carious lesion and the pulp.

Exclusion Criteria:

• Medically compromised patients.
• Permanent molars with MIH with the following indices (1, 2c, 4c, 0, 1).
• Permanent molars with MIH with severe post eruptive breakdown therefore, unrestorable.
• Permanent molars with MIH with clinical/radiographic signs and symptoms of irreversible pulpitis or pulpal necrosis.
• No clear band of dentine radiographically between the carious lesion and the pulp.