Clinical outcomes of composite restorations with or without a glass ionomer liner after selective caries removal to soft dentin: a 36-month randomized controlled trial

OBJECTIVES: Selective caries removal to soft dentin (SCR-SD) is currently recommended for the management of deep dentine caries lesions in permanent teeth. However, whether a pulp-protective liner is required after SCR-SD remains uncertain. This randomized controlled trial compared the clinical performance and pulp vitality outcomes of composite resin restorations using a universal adhesive with or without a glass ionomer cement (GIC) liner after SCR-SD in deep caries lesions of permanent posterior teeth. METHODS: A randomized controlled clinical trial was conducted in 144 deep dentin caries lesions from 98 participants aged 9 to 55 years. After SCR-SD, lesions were randomly allocated to one of two restorative strategies: a universal adhesive applied in selective enamel etching mode (SE) and composite resin without a GIC liner, or a conventional GIC liner followed by the same universal adhesive applied in selective enamel etching mode and composite resin (GIC + SE). Restorations were followed for 30-36 months. The primary outcome was restoration survival, assessed using selected FDI criteria. The secondary outcome was pulp vitality preservation. Survival analyses were performed using Weibull regression models. RESULTS: Of the 144 treated lesions, 117 were evaluated after 30-36 months. Restoration survival did not differ significantly between groups, with survival rates of 96.0% for SE and 92.4% for GIC + SE (p = 0.37). In contrast, pulp vitality preservation was significantly higher in the SE group than in the GIC + SE group, with success rates of 97.5% and 87.3%, respectively (p = 0.01). In the adjusted Weibull regression model, SE was associated with a lower risk of pulp vitality failure compared with GIC + SE. Restorative failure was also strongly associated with pulp vitality failure. CONCLUSIONS: The use of a GIC liner after SCR-SD did not improve restoration survival and was not associated with better pulp vitality preservation. Composite restorations using universal adhesive applied in selective enamel etching mode placed directly over the remaining dentin showed favorable restorative and biological outcomes after 30-36 months. These findings suggest that routine liner placement after SCR-SD may not be necessary. CLINICAL SIGNIFICANCE: In deep dentin caries lesions treated with SCR-SD, placing a glass ionomer liner before composite restoration using a universal adhesive did not improve clinical outcomes. Effective sealing is achieved using universal adhesive applied in selective enamel etching mode and nanofilled composite resin. These simple clinical procedures maintained the restoration integrity and pulp vitality. Registered on https://www. CLINICALTRIALS: gov (NCT04250142).