A Primary Care Randomized Controlled Trial of Hall and Conventional Restorative Techniques

To investigate treatment outcomes of different restorative techniques undertaken by dental therapists for primary molar carious lesions in a sample of children in New Zealand primary care.

This was a randomized controlled trial with children aged 3 to 8 y in New Zealand's Whanganui region. Children meeting inclusion criteria were randomly allocated to treatment with either the Hall technique (HT), in which a stainless-steel crown (SSC) is placed without any carious tissue removal or tooth preparation, or a non-Hall conventional restorative approach (NHT), including tooth preparation with selective carious tissue removal; this included SSC, amalgam, composite, or glass ionomer cement (GIC) restorations. Restorative outcomes after 12 and 24 mo were categorized as success, minor failure, or major failure.

Of the 295 eligible children, 149 and 146 were allocated to the HT and NHT groups, respectively, with a total of 570 carious primary molars treated by 13 dental therapists. The participant follow-up rates at 12 and 24 mo were 95% and 91%. SSCs were the most commonly used restoration in the NHT group (60%), followed by GIC (28%). SSCs were the most successful restorations regardless of whether they were placed with the HT or NHT, with success rates of 89% and 92% at 12 mo and 85% and 86% at 24 mo. In the NHT group, the treatment material was a predictor of minor failure at 12 and 24 mo, with significantly more failures with GICs.

SSCs placed by dental therapists are a highly successful restoration for the primary dentition, regardless of whether they are placed with the HT or conventionally. The high failure rate of glass ionomer restorations means that they cannot be recommended for widespread use in New Zealand primary care (Australian New Zealand Clinical Trials Registry, ACTRN12614000844640).

The findings of this study can be used by policy makers and clinicians when deciding on which materials and which approach to use to maximize success and to minimize retreatment rates when providing restorative treatment for carious primary molars in children's primary oral health care. Results also suggest that undertaking research in the primary care setting may enhance translation of new knowledge and techniques into clinicians' hands.