Chemomechanical caries removal in primary teeth in a group of anxious children G. ANSARI*, J. A. BEELEY † & D. E. FUNG † *Paedodontic Department, Dental school, Shahid Beheshti University of Medical Sciences, Tehran, Iran and † Child Dental Care and Oral Sciences, University of Glasgow Dental Hospital and School, Glasgow, UK SUMMARY Chemomechanical removal of dental car- ies has considerable potential in the treatment of patients with management problems, especially in paediatric dentistry. The aim of this study was to assess the acceptance and success of the technique in young nervous patients. A group of 20 patients, aged between 4 and 10 years with a high level of dental anxiety was selected. The study achieved a success rate of over 90% in acceptance of cavity preparation by this procedure followed by placement of a restoration. The length of time required for cavity preparation was comparable with conventional methods. The need for local anaesthesia was reduced or eliminated and the children did not complain of any pain during the procedure. It is concluded that chemomechanical caries removal in vivo in primary teeth is an effective alternative to conventional mechanical caries removal and is advantageous in patients who have a phobia to the dental handpiece and/or injections. KEYWORDS: anxiety, chemomechanical, Caridex, car- ies, primary, N-monochloro-DL-2-aminobutyric acid, N-monochloroglycine Introduction Chemomechanical caries removal involves the selective removal of soft carious dentine without the painful removal of sound dentine. The procedure initially involved the use of N-monochloroglycine (NMG) formed by mixing glycine and sodium hypochlorite but was subsequently improved by replacing glycine with DL-2-aminobutyric acid in which case the active component was N-monochloro-DL-2-aminobutyric acid (NMAB) (Schutzbank et al., 1978). The mechanism of action probably involves the chlorination of partially degraded collagen in carious dentine and the conver- sion of proline to pyrrole-2-carboxylic acid which results in disruption of the collagen matrix (Habib, Kronman & Goldman, 1975). The US Food and Drug Administration have approved the reagent as safe and effective. More recently, a gel (Carisolv, Medi Team Dental AB, Gothenburg, Sweden) was introduced as an alternative chemomechanical caries removal reagent and this has also been claimed to be effective on caries disolution when used with either hand or mechanical rotary instrumentation (Igarashi et al., 1998; Cederlund, Lindskog & Blomlof, 1999). Yamada et al. (2001) investigated the effect of an Er:YAG laser beam on the caries removal properties of Carisolv and concluded that the combination of the two would increase the potential caries removal efficacy which could lead to an acceptable alternative to conventional drilling. The dentinal surfaces formed after chemomechanical caries removal are very irregular with many overhangs and undercuts; patent and occluded dentinal tubules can also be seen (Yip, Beeley & Stevenson, 1991; Yip, Stevenson & Beeley, 1995b). The dentine remaining is sound and properly mineralized and well-suited for restoration and bonding to modern restorative mater- ials (Burke & Lynch, 1990; Yip, Beeley & Stevenson, 1995a). An ultrastructural study on dentine exposed to Carisolv gel and sodium hypochlorite revealed no effect on sound and demineralized dentine in the group exposed to Carisolv gel, while sodium hypochlorite (0®25%, w ⁄ v) removed all layers of denatured collagen completely (Hannig, 1999). Although hard eburnated dentine may remain, recent studies have shown that this contains few viable microorganisms and its removal may not be necessary (Kidd, Joyston-Bechal ª 2003 Blackwell Publishing Ltd 773 Journal of Oral Rehabilitation 2003 30; 773–779