Organisational and regulatory challenges.

Clinical trial to investigate the clinical efficiency of resin infiltration compared to microabrasion in the improvement of dental fluorosis.

Dental fluorosis is an endemic public health concern that develops if infants are subjected to excessive amounts of fluoride during enamel formation. Anatomopathologically, dental fluorosis presents itself as a hypermineralized surface layer and subsurface hypomineralization involving the external third of the thickness of the enamel, which is equivalent to early carious lesions. In addition, fluorosis features a number of clinical changes in the enamel surface, ranging from the appearance of thin white lines up to severe structural defects, thereby compromising overall esthetics, which sometimes leads to children dropping out of school due to its psychological impact.

The aim of this controlled clinical trial is to evaluate the efficacy of enamel microabrasion and resin infiltration in improving the dental esthetic of patients with fluorosis. Resin infiltration is a microinvasive technique that can improve the esthetics by infiltrating a low-viscosity resin (that has a similar refractive index to enamel) into the porose hypomineralized enamel of fluorosed white spots. This approach thus largely preserves the enamel compared to more invasive techniques such as microabrasion and has been shown to be efficient in previous studies.

This study will be conducted in the provinces of Pichincha and Cotopaxi, Ecuador and patients between 10 to 12 years of age with stage 1, 2, and 3 fluorosis according to the Thylstrup and Fejerskov (TF) scale or questionable, very mild, and mild fluorosis according to Dean's Index will be recruited. In addition to the immediate esthetic improvement, long term stability of the outcome will be assessed at 3, 6 and 12 months.

Inclusion Criteria:

• Questionable, Very mild, and Mild (Dean's Index) dental fluorosis as well as TF scale grades 1, 2, and 3 of the upper anterior teeth.
• Parents of children who accept and commit to the informed consent letter collaborate with the study taking their children to each of the scheduled follow ups.

Exclusion Criteria:

• Teeth without fluorosis.
• Teeth with hypoplasia.
• Teeth with incipient caries lesions observed at gingival level and differentiated by the Presence of plaque.
• Teeth previously restored or with aesthetic corrective treatments
• Teeth with endodontic treatment.
• Patients with low or questionable hygiene.
• Malnourished patients or that have some underlying disease.
• Teeth with less than two thirds of its visible crown.
• Children that have less than six teeth in their oral cavity.
• Allergic reaction to methylmethacrylate.