Abstract
Background: The Hall technique (HT) for placing stainless steel crowns is an approach to primary molar carious lesion management in which the lesion is sealed in rather than surgically excised. Overseas studies of the HT used by dentists showed better success rates than conventional restorations, and one study indicated that children preferred the HT to conventional restorations.
Aims and Objectives: The aim of this thesis was to research the use of the HT in New Zealand (NZ) primary care. The objectives were: (1) to test research methods, assess the training in, acceptability of, and outcomes of the HT in the hands of dental therapists in primary care in a feasibility study, and to compare the clinical outcomes with those of conventional restorative treatment; (2) to compare the clinical outcomes of the HT and conventional restorative treatment in a large randomised control trial (RCT); (3) to evaluate the consent process involved in a dental RCT; and (4) to evaluate clinical outcomes of the HT and conventional SSC in a RCT, and children’s procedural pain experiences with these different treatments.
Methods: Three clinical trials took place, all in the NZ primary care setting, with dental therapists (DTs) providing treatment to children between three and eight years of age. The first was a feasibility study with an interventional (quasi-experimental) design and two-year follow-up; this was followed by two RCTs with two-year and 18-month follow-ups, respectively. Evaluation of the consent process in the final RCT used mixed quantitative and qualitative methods, with one-to-one telephone interviews with caregivers of children taking part in the RCT, and analysis with an inductive approach.
Results: DTs who had the appropriate training were adept at the HT and accepted it. A successful outcome was recorded significantly more in teeth treated with SSCs, regardless of whether these had been placed using a conventional approach or using the HT, and glass ionomer cement restorations (GIC) performed poorly. Moderate and severe procedural pain was reported by as many children when they had treatment with the HT as when they had a conventional SSC; dental anxiety scores did not predict the children who reported moderate or severe procedural pain. Gaining caregivers’ informed consent for their child to participate in a randomised control trial was a complex undertaking, and the informed consent process was not always effective, despite the consent documents having high readability.
Conclusions: There are much lower retreatment rates for children with carious primary molars treated with the HT than with conventional GIC restorations. SSCs placed with the HT have similar success rates to SSCs placed conventionally. The lack of a difference in self-reported procedural pain between HT and conventional SSC compromises the child-friendliness of the HT, and, to improve children’s experiences, further research is required on using comfort management strategies, and on preventing dental caries. Pre-testing RCT consent documentation within the population to be studied is recommended to enhance the consent process. Further research on children’s understanding of their participation in a RCT is required.