Clinical efficacy of orifice barriers in endodontics: A systematic review

Orifice barriers (OBs) are commonly placed as sub-seals following root canal treatment, to resist microbial leakage if the primary coronal seal fails. However, despite numerous in vitro studies, clinical evidence supporting their efficacy is limited. This is the first systematic review of the in vivo endodontic literature evaluating OB effectiveness in root filled teeth (RFT), addressing a critical research gap.

MEDLINE, Embase, CENTRAL, Web of Science and Scopus were systematically searched from inception through 16^th May 2025. Articles were screened using Covidence by two independent reviewers. Risk of bias and certainty of evidence assessments were undertaken to assess methodological rigour of included studies.

Seven studies met the inclusion criteria. OBs improved outcomes for teeth with radicular cracks in two small single-arm cohort studies (90.6 % success & 96.6 % survival at 2-4years; 100 % at 1-3years). OBs were associated with lower apical periodontitis (AP) in one cross-sectional study (p < 0.005), while in a second, positioning the root filling/coronal restoration interface apical to marginal bone level was associated with lower AP (p < 0.005). Two remaining cohort studies showed no significant benefit for OBs in RFT. One randomised controlled trial showed no benefit of OBs, but follow-up was only one year. Heterogeneity among studies precluded meta-analysis.

Very low certainty in vivo evidence supports OBs in cracked RFT, but there is little evidence for OBs elsewhere. The limitations identified underscore the need for well-designed prospective in vivo studies to validate the evidence base for OBs.

OB placement apical to radicular cracks may improve success and survival for cracked RFT, with specialist referral for treatment under microscopy recommended in such cases. OBs may play a role in creating a well-sealed coronal restoration following RCT, but further clinical research is required to determine their efficacy.