Diagnostic Reference Levels for Dental Cone Beam Computed Tomography: A Critical Appraisal of Global Progress and Remaining Gaps.

Cone beam computed tomography (CBCT) is now firmly established in dental and maxillofacial practice, providing three-dimensional visualization for implant planning, endodontics, orthodontics, and oral surgery. However, the expansion of the use of dental CBCT units worldwide has outpaced efforts to standardize and optimize radiation doses delivered to patients. Diagnostic reference levels (DRLs) are meant to fill this gap, acting as benchmarks that flag facilities where doses may need investigation or optimization. Despite this well-established regulatory concept, uptake of DRLs for dental CBCT varies widely from one country to the next. In this review, we examine where things currently stand globally: the regulatory basis for DRLs, the dose metrics and classification schemes different countries rely on, the DRL values reported in national documents and peer-reviewed literature, and the methodological inconsistencies that make cross-country comparison difficult. Only a small number of countries, mostly in Europe and Japan, have published official national DRLs for dental CBCT. Even among these, there is substantial variation in the dose descriptor used (dose-area product being the most common), in whether classification is based on field of view or clinical indication, and in the resulting DRL values themselves. Perhaps most notably, only one country has established pediatric-specific DRLs for dental CBCT. We also consider the barriers standing in the way of wider adoption: uneven regulatory infrastructure between countries, a lack of standardized dosimetric protocols for CBCT, limited participation in national dose surveys, and the particular difficulty of overseeing CBCT use in private dental practices that fall outside conventional radiology governance. Moving forward, harmonizing dose metrics internationally, expanding multinational surveys, integrating automated dose-tracking tools, and prioritizing pediatric dose optimization will all be important. Building a stronger global framework for dental CBCT DRLs is essential to keeping pace with an imaging modality that continues to grow in clinical utilization.