Success rate of Hall Technique for restoring carious primary molars - systematic review and meta-analysis

The overall pooled success rate of the Hall Technique (HT) in various types of studies has not been investigated. The present study aims to evaluate the success rate of HT to restore carious primary molars.

A systematic search was carried out in the MEDLINE/PubMed, Excerpta Medica Database (EMBASE), Scopus, Web of Science, and LIVIVO electronic databases, as well as the ProQuest database for grey literature review. A search was carried out up to September 2023 for studies meeting the eligibility criteria: Randomised Clinical Trials (RCTs) and Non-Randomised Studies of Interventions (NRSIs); children with primary molars treated using HT; and reporting success for at least 1-month post-treatment. Single-arm meta-analysis assessed the pooled proportion (95% CI) of HT success rates. Risk of bias and certainty of evidence using the GRADE approach were assessed.

Searching identified 665 studies, with 25 (15 RCTs and 10 NRSIs) meeting the eligibility criteria. In meta-analyses of RCTs, the pooled proportion success rate was 98% (95% CI: 97-99%) at 12-month follow-up. For NRSIs, the pooled proportion success rate was 95% (95% CI: 91-100%) up to 89 months.

HT presents a high success rate, even though the primary studies had "low" to "high" risk of bias and demonstrated "moderate" to "low" certainty of evidence. One of the main reasons for downgrading was related to blinding, which was generally unfeasible due to visibly different restorative materials. The systematic review protocol was registered in PROSPERO (ID: CRD42021204415).