Calcium silicate liner versus no liner in selective caries removal: a one-year randomized clinical trial

Selective removal to soft dentine (SRSD) is recommended to minimize pulp exposure in deep carious lesions. The use of calcium silicate-based liners has been advocated to enhance pulp protection; however, their true clinical benefit remains controversial. This study aimed to compare the clinical and radiographic success of the SRSD technique with and without the use of a bioactive liner in permanent posterior teeth with closed apex after 12 months. A double-blind, randomized controlled trial was conducted in patients aged 15–62 years with deep carious lesions in posterior permanent teeth with normal or reversible pulpitis. Teeth were randomly assigned to two groups: application of a hydraulic calcium silicate-based cement (Biodentine™) or no liner (direct adhesive procedure). All cavity preparations and restorations were performed under rubber dam isolation. The primary outcome was treatment success (maintained or lost vitality at 12 months), with the tooth as the unit of analysis. Success was defined as absence of symptoms, normal pulp sensibility response, no clinical signs of inflammation or infection, and absence of periapical pathology on radiographs. Continuous and categorical variables were compared using Wilcoxon and Fisher’s exact tests, respectively, with FDR-adjusted p-values (α = 0.05). A total of 45 teeth in 32 patients were treated. At the 12-month follow-up, 33 teeth were available for evaluation, corresponding to a drop-out rate of 26.7% at the restoration level. At the patient level, the overall drop-out rate was 37.5%. Both groups achieved 100% success rates with no statistically significant differences. All teeth maintained normal pulp responses, were asymptomatic, and showed healthy periapical structures. Restoration quality was acceptable according to FDI criteria, with no failures or adverse events recorded. After 12 months, the use of a calcium silicate-based liner did not significantly impact the clinical or radiographic success of the SRSD technique in deep caries lesions. A direct adhesive approach without a liner may be a reliable, simpler, and cost-effective alternative for maintaining pulp vitality. The study was approved by the University Ethics Committee (protocol code 0212202023220) and registered at ClinicalTrials.gov (Identifier: NCT04743219; date of registration: 01/02/2021).