Ultrastructure and properties of primary carious molars treated using the hall technique.

BACKGROUND The Hall Technique (HT) is a method of restoring decayed primary teeth using stainless steel crowns (SSCs) without tooth preparation, caries removal or local anaesthetic. AIM To investigate the ultrastructural, biomechanical and chemical characteristics of teeth managed with the Hall Technique in comparison to conventional SSC (controls). DESIGN Twelve HT-treated primary molars and four controls were analysed. Teeth were dehydrated in ethanol, embedded in methylmethacrylate, mesio-distally sectioned, X-rayed, mounted and polished. Biomechanical, ultrastructural and chemical characterisation was performed for carious lesion and sound areas of each specimen. RESULTS Pre-treatment and post-treatment X-rays showed evidence of little to no caries progression over time. In carious lesions, mean hardness and elastic modulus values were lower in HT-treated teeth than in controls. In both controls and HT-treated teeth, carious lesions had the lowest %wt of Ca and P of all tissues sampled. CONCLUSIONS Although the retained carious tissue was biomechanically more compromised in HT-treated teeth, the Ca and P values were higher than reported elsewhere for carious lesions in primary molars, suggesting remineralisation may have occurred in caries in HT-treated teeth. Future investigations will help elucidate the processes involved with carious lesion arrest under SSC.