Objective: The study's main purpose is to evaluate and compare the clinical and radiographic outcomes of Biodentine and a light-activated calcium hydroxide based-liner (Ultra-Blend plus®) as indirect pulp treatment (IPT) liners, over the dentin-pulp complex of vital primary molars with carious lesions approaching the pulp. Study design: 80 four-to-eight year-old patients were enrolled from a Mexican University Pediatric Dentistry Clinic. A split-mouth design trial is being conducted in order to compare both IPT interventions on 160 bilateral primary teeth, without signs or symptoms of irreversibly inflamed or degenerative pulp tissue. Teeth were treated and restored with a preformed crown in a single session, and then closely followed-up for 1, 3, 6, 12, 18, and 24 months.

A Split-mouth clinical trial was the design selected. Clinical Procedures: IPT procedures were carried out by three pediatric dentistry residents (E.K.C.G., R.A.V.V., and J.M.A.R.), previously trained in the clinical setting with a pilot sample of 10 similar child patients each. Study participants received local anesthesia and rubber dam isolation, which was disinfected, followed by the remove of the carious peripheral dentin with high speed tungsten-carbide bur # 3, and air-water spray. Then, the soft dentin layer was carefully removed with a sharply-edged sterilized hand excavator, based on tactile and visual standards, leaving only the hard dentin adjacent to the pulp ceiling. The cavity was thoroughly rinsed only with water and then dried with sterilized cotton pellets; no other special disinfection protocol was applied. The next step consisted in the placement of the correspondent liner over the remanent carious dentin layer, following the manufacturers' instructions, and according to the randomly assignment scheme previously described. In the case of the control group, the liner was cured undr 20 seconds of light exposure. All treated molar were restored with stainless steel preformed crowns (3M ESPE) cemented with glass ionomer (Ketac-Cem, 3M ESPE). One week later, the same procedure was repeated in the opposite tooth with the contrary IPT agent.

Inclusion criteria:

• At least one restorable first or second primary molar in each side of the mouth, affected by an occlusal cavitated active caries lesion in deep dentin.
• Cooperative patients.
• Participants were included in the trial after parental acceptance through a signed informed consent.

Exclusion criteria:

• Molars with mobility, spontaneous pain or fistula, and radiographic findings such as a carious lesion with no evidence of residual dentin over the pulp chamber or manifest pulp exposition.
• Normally internal root resorption or physiological root resorption less than 1/3.
• Presence of periradicular/furcal radiolucent lesions.
• Occurrence of a carious pulp exposure and bleeding during the operative procedure.

Yes. Only in case of future systematic reviews with meta-analysis.