Antibacterial effects of cavity lining: a systematic review and network meta-analysis.

OBJECTIVES: Cavity liners are frequently used prior placing a restoration, with one main aim being to reduce the number of remaining bacteria. We systematically appraised studies comparing antibacterial effects of different liners against each other or no liner.

DATA STUDIES: reporting the number of sterile cavities before/after lining or sealing, or the reduction in bacterial numbers (colony-forming-units) in two or more treatment groups were included. Treatments were categorized as: no/placebo liner, calcium hydroxide, mineral trioxide aggregate, antibiotic/disinfectant, calcium phosphates, zinc oxide eugenol, black copper cement, and glass ionomer cement liners. Pairwise and network meta-analyses were performed.

STUDY SELECTION: From 113 identified studies, 14 (500 treated lesions) were included. Risk of bias was high or unclear. Based on 11 studies, network meta-analysis found mineral trioxide lining to yield the greatest probability of achieving sterile cavities after a lining/sealing period (73%), followed by antibiotic/disinfectant (8%) and zinc oxide eugenol (7%). Only six studies assessed bacterial reduction after lining/sealing, and zinc oxide eugenol was found to have the highest probability of achieving a bacterial reduction. In both analyses, not providing any lining was found to have low antibacterial effects.

CONCLUSION: Within the limitations of this review and the included studies, certain liners seem more suitable to achieve sterile cavities or reduce bacterial numbers than others. Given the paucity of data and the unclear impact of remaining bacteria on clinical outcomes, further recommendations for specific cavity treatments prior a restoration are not possible.

CLINICAL SIGNIFICANCE: There is insufficient evidence to generally recommend cavity lining or the use of any specific liner based on their antibacterial effects. Dentists might continue to use liners, but should be aware that such use is not strongly supported by clinical studies.