An improved reagent for chemomechanical caries removal in permanent and deciduous teeth: an in vitro study

An in vitro study has been carried out on the chemomechanical removal of caries in deciduous and permanent teeth. The aims of the study were to compare the efficacy of caries removal by various chemical agents including N-monochloro-DL-2-aminobutyrate (NMAB) and NMAB containing urea (NMAB-urea), to compare the efficacy on permanent and deciduous teeth and to study the dentinal surfaces produced.

The addition of urea to NMAB resulted in an improvement in the efficacy of caries removal. Sodium hypochlorite, saline and urea alone were also studied as caries removal agents, but were not significantly different from NMAB. Chemomechanical caries removal solutions were more effective in removing caries from deciduous teeth than from permanent teeth, especially in terms of the volume of solution used. The improvement on addition of urea was found to be greater in deciduous than in permanent teeth, the number of deciduous teeth with 'complete cares removal' being increased by about 25%. The dentinal surfaces of the cavities prepared using these solutions and in which 'complete caries removal' had been achieved were studied by scanning electron microscopy. Generally after treatment with NMAB or NMAB-urea, the surface appearance was very uneven with many undermined areas. NMAB-urea produced a 'cleaner' surface compared with that produced by NMAB alone.

NMAB appears to be potentially more effective and clinically more useful in removing caries in deciduous teeth than in permanent teeth, and the addition of urea may enhance its efficacy, especially in the treatment of paediatric dental patients.