Supplementary Material for: Dental practitioners’ thresholds for restorative intervention in carious lesions: a survey based systematic review update

Introduction: Despite evidence supporting the clinical and cost-effectiveness of Minimally Invasive Dentistry (MID), its adoption by the dental profession has been slow. A systematic review in 2016 found the majority of dentists intervene invasively earlier than necessary. The aim was to update this review of the assessment of dental practitioners’ thresholds for providing restorative treatment for carious lesions given changes in evidence, teaching and guidelines since 2016. The primary outcome was dental practitioners’ restorative thresholds (the extent of the lesion when they would decide to intervene restoratively). Secondary outcomes were changes over time; caries risk; regional differences and primary/permanent dentition. Methods: This updated review replicated the methodology for the initial review, following the PRISMA 2020 guideline (PROSPERO; CRD42023431906). EMBASE, Medline (via PubMed) and Web of Science databases were searched (2016 to 2023) for observational studies reporting on dental clinicians’ thresholds for restorative interventions in adults and children without language, time or quality restrictions. Screening, data extraction and risk of bias assessment (Modified Newcastle-Ottawa Scale) were carried out independently and in duplicate. Meta-analyses were performed using a random effects model. No funding sought. Results: Overall, 47 publications (30 from original publication and 17 from updated search) met the inclusion criteria and 65 datasets were included in the meta-analyses; 19 for occlusal lesions (16 pre-2016 and 3 post-2016; n=11,946) and 46 for proximal lesions (38 pre-2016 and 8 post 2016; n=20,428). The meta-analyses found that for occlusal lesions confined to enamel, there were fewer practitioners intervening invasively: 5% (95% confidence interval [CI]; 1-20%) post-2016, compared with 15% (95% CI; 9-23%) pre-2016. The opposite was found for proximal lesions with increased intervention levels, 27% (95% CI; 18-40%) for lesions confined to enamel post-2016, compared with 19% (95% CI; 12-29%) pre-2016, and for lesions extending up to the enamel-dentine junction 61% (95% CI; 36-81%) post-2016, compared with 39% (95%CI; 29-51%) pre-2016. There was variance between regions but too few studies to draw conclusions on individual regions. Conclusion: There was suggestion of less invasive treatment of occlusal lesions over time, however this was not evident for proximal lesions.