Interventions to Control Hypersensitivity Pain in Teeth With Insisive Molar Hypomineralization

Molar incisor hypomineralization (MIH) manifests as a qualitative, demarcated defect in tooth enamel of systemic origin, predominantly affecting one or more permanent first molars, and potentially extending to the incisors. One significant challenge in managing this enamel anomaly is hypersensitivity, leading to discomfort and pain in affected patients. Low-intensity laser therapy, alone or combined with other modalities, appears promising in alleviating pain associated with MIH. This study aims to assess the efficacy of low-intensity laser therapy using varied parameters, in conjunction with a remineralizing agent, for pain management in children with molar incisor hypomineralization. Participants aged 6 to 12 years will be recruited, with a total of 88 teeth diagnosed with MIH, presenting a sensitivity score ≤3 on the Visual Analog Scale (VAS) and a score ≤1 on the Schiff Cold Air Sensitivity Scale (SCASS). The teeth will be randomly assigned to one of four groups (n=22 each): Group I (GI): L-1J + VF, Group II (GII): L-1J + VP, Group III (GIII): L-2J + VF, and Group IV (GIV): L-2J + VP. Here, 'L' denotes low-intensity laser application at different parameters (1J and 2J), combined with either fluoride varnish (VF) or a placebo varnish (VP). Interventions and assessments will be conducted initially, after 48 hours, and at 1 and 2 weeks post-treatment. Patients will undergo re-evaluation at 2, 4, 8, and 12 weeks following interventions. Statistical analyses will be performed with a 95% confidence level (α = 0.05).

A randomized clinical trial will be carried out involving children aged 6 to 12 years, with a total of 88 teeth diagnosed with MIH, presenting a sensitivity score ≤3 on the visual analogue scale (VAS) and a score ≤1 on the Schiff Cold Air Sensitivity Scale (SCASS). ). Inclusion criteria will require the presence of at least one erupted permanent molar with an occlusal surface free of gingival tissue, demonstrating IMH with sensitivity. Additionally, participants must provide informed consent forms signed by parents or guardians, along with consent forms signed by children. Exclusion criteria include decayed teeth, atypical carious lesions, teeth that have other enamel defects such as fluorosis, enamel hypoplasia, amelogenesis imperfecta or enamel malformations associated with syndromes, ongoing orthodontic treatment, cognitive disorders in patients, desensitizing treatments recent use in the last 3 months, previous use of anti-inflammatory and/or analgesic medications, teeth diagnosed with MIH presenting post-eruptive dentin fractures, atypical restorations, atypical caries, sensitivity scores \>3 on the visual analogue scale (VAS) and scores \> 1 on the Schiff Cold Air Sensitivity Scale (SCASS).

For the diagnosis of MIH, the investigators will employ the criteria outlined by the European Academy of Pediatric Dentistry, which includes assessment of demarcated opacities, post-eruptive enamel defects, atypical restorations, teeth lost due to MIH, and incompletely erupted teeth. The sample size was determined based on the anticipated outcome of pain reduction following treatment, with an expected 60% reduction. Calculation was conducted with a confidence level of 95% and a power of 80%.

Following the application of the inclusion and exclusion criteria, each group will consist of a total of 88 teeth, randomly assigned to one of four groups: GI, GII, GIII, and GIV. The interventions for each group will be as follows:

GI: Low-Intensity Laser 1J (10 seconds) + Fluoride Varnish. GII: Low-Intensity Laser 1J (10 seconds) + Placebo. GIII: Low-Intensity Laser 2J (20 seconds) + Fluoride Varnish. GIV: Low-Intensity Laser 2J (20 seconds) + Placebo.

To administer laser therapy, the investigators will utilize a low-intensity infrared diode laser (Therapy EC, DMC Equipamentos Ltda., São Carlos, Brazil) operating in continuous mode, emitting at a wavelength of 808 nm with a power output of 100 mW. The dosage will be set at either 1 or 2 Joules, with a fluence of 35 J/cm\^2. Both the operator and the patient will wear personal protective equipment (PPE) during the procedure. The tooth will be irradiated perpendicular to the tooth surface, targeting the cervical third of the buccal surface (both mesial and distal aspects), as well as the center of the lesion. Activation time will be either 10 or 20 seconds, corresponding to 1 or 2 Joules respectively, depending on the assigned group. To ensure consistency, even if the laser is activated for 1 Joule (equivalent to 10 seconds), the laser tip will be maintained in place for a standardized duration of 20 seconds, the maximum activation time, as confirmed by a stopwatch in all applications to ensure reliability.

As an adjunct to LBI, the investigators will use a fluoride varnish (FV) and a placebo varnish (PV) without the active ingredient, ensuring that they are in identical packaging with the same taste and texture. Both will maintain the same method of application. The FV used will be Duraphat® (22,600 ppm F, Colgate). The application of both FV and PV will be conducted according to each respective group. Application will be facilitated using a microbrush, spreading it over the entire lesion area for 30 seconds. After the interventions, patients will be instructed not to consume hard foods and to refrain from brushing their teeth for at least four hours following varnish application, adhering to the manufacturer's recommendations.

Following all tests, the data will undergo normality analysis (Shapiro-Wilk test) and homoscedasticity assessment (Levene's test) to determine the suitability of parametric statistics. Therefore, for all variables, one-way ANOVA will be employed, followed by Tukey's post-hoc test for group comparisons. Demographic data will be evaluated using Pearson's chi-square test. Friedman's test may be utilized for multiple comparisons (sensitivity assessments), and the Wilcoxon test for paired comparisons. Analyses will be conducted using the statistical software SPSS 12.0 (SPSS Inc., Chicago, IL, USA). All tests will be performed at a 95% confidence level (α = 0.05).

Eligibility Criteria:
Inclusion Criteria:

* Children aged 6 to 12 years old
* Teeth diagnosed with MIH, exhibiting at least one erupted permanent molar with the occlusal surface devoid of gingival tissue and showing sensitivity associated with MIH with sensitivity score ≤3 on the Visual Analogue Scale (VAS) and score ≤1 on the Self-Consensus Assessment scale symptoms and signs (SCASS).
* Children who have the cognitive ability to answer the tests.
* Children who obtained authorization from their parents or guardians, through a signed free and informed consent form.

Exclusion Criteria:

* Decayed or restored teeth.
* Teeth with other enamel defects, such as fluorosis, enamel hypoplasia, amelogenesis imperfecta or enamel malformations associated with syndromes, as well as those undergoing orthodontic treatment.
* Patients with cognitive impairments that prevent responsiveness to the test.
* Children who have undergone desensitizing treatment in the last 3 months.
* Children who use anti-inflammatory and/or analgesic medications before starting treatment.
* Teeth that have a sensitivity score \>3 on the visual analogue scale (VAS) and a score \>1 on the Schiff Cold Air Sensitivity Scale (SCASS).