The aim of this study was to evaluate the survival of direct composite resin restorations in primary molars using different methods of isolation of the operative field: absolute isolation (local anesthesia, use of dental clamp and rubber dam) and relative isolation (cotton rollers and saliva ejector) by a randomized clinical trial. All composite restorations will be performed on children aged 4 to 10 years who present at least one dentin caries lesion or restoration needing replacement, without pulp involvement in a primary tooth. The treatments will be performed in the dental clinic of the University of São Paulo (FOUSP) by trained operators. The teeth will be randomized between the groups: Absolute Isolation (AI) and Relative Isolation (IR) and restored with composite resin (Scotchbond Universal Adhesive adhesive system and Filtek BulkFill composite resin - 3M ESPE) stratified by surface (single or multi surface). Restoration evaluation will be performed after 6, 12, 18, and 24 months by a blind, trained and calibrated examiner. As a primary outcome, the survival of the restorations will be evaluated. The secondary outcomes involve the procedure time (in minutes), professional and material cost (in Brazilian reais), as well as the cost-effectiveness of the restorations and the discomfort reported by the patient (measured using the Wong-Baker scale). The Kaplan-Meier survival analysis and log-rank test will be applied to the survival of the restoration. All variables will be modeled and compared with a Cox regression model of shared fragility. The discomfort reported by the patient will be analyzed by Ordinal Logistic Regression (α = 5%).

Objective:

The aim of this study is to evaluate the survival of direct composite resin restorations in primary molars using different methods for isolation of the operative field: absolute isolation (local anesthesia, use of dental clamp and rubber dam) and relative isolation (cotton rollers and saliva ejector) by a randomized clinical trial.

Materials and Methods:

All composite restorations will be performed on children aged 4 to 10 years who present at least one dentin caries lesion or restoration needing replacement, without pulp involvement in a primary tooth. The treatments will be performed in the dental clinic of the University of São Paulo (FOUSP) by trained operators. The teeth will be randomized between the groups: Absolute Isolation (AI) and Relative Isolation (IR) and restored with composite resin (Scotchbond Universal Adhesive adhesive system and Filtek BulkFill composite resin - 3M ESPE) stratified by surface (single or multi surface).

Restoration evaluation will be performed after 6, 12, 18, and 24 months by a blind, trained and calibrated examiner.

As a primary outcome, the survival of the restorations will be evaluated. The secondary outcomes involve the procedure time (in minutes), professional and material cost (in Brazilian reais), as well as the cost-effectiveness of the restorations and the discomfort reported by the patient (measured using the Wong-Baker scale).

The Kaplan-Meier survival analysis and log-rank test will be applied to the survival of the restoration. All variables will be modeled and compared with a Cox regression model of shared fragility. The discomfort reported by the patient will be analyzed by Ordinal Logistic Regression (α = 5%).

Inclusion Criteria:

• who have sought treatment in the University;
• between 4 and 10 years of age;
• with at least one dentin caries lesion without pulp involvement (ICCMS C score);
• need for restoration replacement diagnosed by FDI criteria or CARS criteria;
• absence of pulp involvement diagnosed by interproximal radiography (presence of dentin layer between the caries lesion and the pulp chamber).

Exclusion Criteria:

• children whose parents did not agree to participate in the study:
• children who did not agree to participate or had behavioral problems during the initial consultations.
• signs or symptoms of pulp pathology: spontaneous pain, pulp exposure, abscess or fistula near the tooth to be included, mobility or presence of communication between the caries lesion and the pulp (evaluated by interproximal digital radiography of the diagnosis).

Only the evaluator of the restorations will be blind to the type of treatment (absolute or relative isolation). As the procedures are different, it will not be possible to blind operators and patients.