Molar-Incisor Hypomineralization (MIH) is a qualitative enamel defect caused by systemic hypomineralization that affects one to four first permanent molars, and may or may not involve incisors. The clinical repercussions associated with MIH can be characterized by: painful hypersensitivity, post-eruptive fractures, rapid progression of caries lesions in newly erupted first permanent molars, difficulty in achieving effective anesthesia, aesthetic impairments, and patient fear and anxiety. To date, there is no consensus on the best treatment for sensitivity in teeth with MIH, thus managing sensitivity in these teeth remains a significant challenge. The aim of this study is to evaluate the effectiveness of a 10% Biosilicate® solution as a desensitizing agent in MIH teeth in children, compared to Fluoride varnish (Duraphat® Colgate, Brazil). Children aged 6 to 12 years will be selected for this study, with a total of 63 participants diagnosed with MIH, and a sensitivity score ≥2 on the SCASS scale. The children will be randomly divided into two groups (n=21): GI: Duraphat®, GII: Biosilicate®. Interventions will be performed once a week for 4 consecutive weeks, followed by 8 weeks of follow-up. The results will be subjected to statistical tests with a 95% confidence level (α = 0.05).

This study will evaluate the effectiveness of a 10% Biosilicate® solution as a desensitizing agent in MIH teeth in children, compared to Fluoride varnish (Duraphat® Colgate, Brazil). The children included in the study will be subdivided into three randomized treatment options, which are: Group 1: Fluoridated varnish (Duraphat® Colgate, Brazil); Group 2: Biosilicate® 10%. The randomization sequence will be generated using the envelope method. A numerical sequence (1 and 2) will be printed, which will correspond sequentially to the three groups (GI and GII). The numbers will be placed in envelopes with the same characteristics and then sealed. The implementation of the random allocation sequence will be carried out by a single researcher, who will use the previously sealed envelopes along with the numbers corresponding to the treatments to be administered. As each child is included in the study, an envelope will be labeled with the child's name and will only be opened by the operator before the start of the treatment. Children with the potential for inclusion in the research will be referred for clinical examination in the mobile dental unit (Dental Case), and those with at least one first permanent molar affected by MIH and reporting hypersensitivity, with or without structure loss, will be invited to participate. The complaint of sensitivity will be confirmed by applying a 1-second air blast at a distance of 1 centimeter from the occlusal surface of the tooth; a score of 2 or 3 on the Schiff Cold Air Sensitivity Scale (SCASS) will be considered a positive result.

Inclusion Criteria:

• Children of both sexes, aged between 6 and 12 years.
• Children who have at least one first permanent molar with Molar-Incisor Hypomineralization, showing distinct white or cream opacity (score 21), yellowish or brown opacity (score 22), and/or post-eruptive enamel fracture (score 3), and presence of painful sensitivity when stimulated, with a score of 2 or 3 as evaluated using the SCASS scale.
• Children without systemic and/or cognitive impairments.

Exclusion Criteria:

• Previous use of desensitizing therapy in the last 6 months;
• Use of analgesic and anti-inflammatory medications during the previous 3 days;
• Use of orthodontic appliances;
• Teeth with extensive restorative procedures, such as stainless steel crowns, which prevent the assessment of painful sensitivity;
• Teeth with amelogenesis imperfecta or dentinogenesis imperfecta;
• Children with systemic and/or cognitive impairments.

To ensure the first stage of blinding in the study, the patient will not know which group and type of treatment the tooth will receive. Therefore, we will attempt to standardize some methods to ensure this reliability. The products to be tested will be removed from their original containers and placed in identical 10ml white bottles. The second stage concerns the evaluator. All treatments will be performed by a single operator, and the tests will be applied by another evaluator. In this way, the evaluator will not know the group allocation or the type of intervention that was performed.To increase the reliability of the results, the statistician will also not know the allocation or which groups correspond to each treatment. They will only receive a table with letters representing the groups as A and B and the test values, without knowing which group or interventions were carried out.