Performance of Universal Adhesive in Primary Molars: a Randomized Clinical Trial

The aim of this study is to evaluate the 18-month clinical performance of a multimode adhesive (Scotchbond Universal Adhesive, 3M ESPE, St Paul, MN, USA) in primary molars after partial carious removal. This randomized clinical trial will include subjects (5-10 year-old children) selected at two university centers (UFSM and FOUSP). The sample will consist of 132 primary molars presenting active cavitated carious lesions (with radiographic involvement of the outer half of the dentin), located on the occlusal and occlusal-proximal surface. The sample will be randomly divided into two groups according to bonding approach: etch-and-rinse or self-etch strategy. The restorations will be clinically followed every 6 months for up to 18 months using the USPHS modified criteria for clinical evaluation. Survival estimates for restoration longevity will be evaluated using the Kaplan-Meier method.

The adhesive will be vigorously agitated on the entire enamel and dentin surfaces for 20 seconds, according to the manufacturer's recommendations.The brush will be scrubbed on the dentin surface under manual pressure followed by gentle air thinning for five seconds and finally light curing for 10 seconds.

After acid etching for 15 seconds, the sound and caries-affected dentin will be kept moist.The adhesive will be vigorously agitated on the entire enamel and dentin surfaces for 20 seconds, according to the manufacturer's recommendations.The brush will be scrubbed on the dentin surface under manual pressure followed by gentle air thinning for five seconds and finally light curing for 10 seconds.

The outcome of the study is the failure of restorations in primary teeth. Failures will be assessed by clinical evaluation and will be considered in the presence of loss of restoration or fracture requiring a reintervation (restoration repair or replacement) or symptoms requiring pulp intervention or tooth extraction.

Inclusion Criteria: active carious lesion in middle dentin limited to the occlusal or occluso-proximal surfaces of primary molars; children (male or female) in good general health. Exclusion Criteria: children who refuse or fail to cooperate with the completion of clinical procedure; - teeth without antagonist; carious lesions in inner half of dentin; presence of painful symptoms or signs of pulpal changes.