1. [Chemomechanical means of removing caries--Caridex system]
G Vougiouklakis, D Paroussis Hell Stomatol Chron. 1988 Apr-Jun;32(2):97-102.
In 1976 Goldman M. and Kronman J. reported on the effects of a N-monochloro-DL-2 aminobutyrate (NMAB) solution used as a caries removal agent. Since that time various studies demonstrated the safety and clinical acceptability of the solution. No adverse side effects have been reported for NMAB. NMAB is formed in aqueous solution through the reaction of two separate components supplied as Caridex solution I (dilute DL-2-aminobutyric acid) and II (sodium hypochloride in weak alkaline solution). The Caridex delivery system includes a pump, a heater, a solution reservoir and a handpiece to hold the applicator tip. The Caridex is based on the softening effect of NMAB, when it is applied continuously with the applicator tip to carious lesions. In addition to the Caridex rotary instruments and other devices ordinarily used for cavity preparation are used as required Caridex reduce patient pain and anxiety but also has limitations. It cannot totally replace the conventional methods of caries removal and cavity preparation. It can be used on a supplementary method for caries removal, also it is necessary to balance a some what longer treatment time against its advantages.
2. Specificity of trypsin and alpha-chymotrypsin towards neutral substrates
T Vajda, T Szabó Acta Biochim Biophys Acad Sci Hung. 1976;11(4):287-94.
Steady state kinetics of the hydrolysis by trypsin and chymotrypsin of the ethyl esters of the N-acetyl derivatives of glycine, L-alanine, DL-2-aminobutyric acid, L-norvaline, L-valine, L-norleucine and L-leucine were studied at pH 6.6 and 25 degrees C. It is apparent from the second-order rate constants, kcat/Km, app, that there is a significant difference between the specificities of the two enzymes toward substrates with a long side chain, such as the derivatives of norvaline, norleucine and leucine. The carboxylate ion Asp-189 in the specificity pocket of trypsin seems to interfere with the productive binding of substrates containing apolar side chains longer than those of the derivatives of DL-2-aminobutyric acid or L-valine. The basic group of the specific substrates of trypsin, such as that of lysine and arginine derivatives, promotes the binding of the apolar side chain by neutralizing the negative carboxylate ion of Asp-189.
3. Mineral content of the dentine remaining after chemomechanical caries removal
H K Yip, J A Beeley, A G Stevenson Caries Res. 1995;29(2):111-7. doi: 10.1159/000262051.
Although the dentine remaining after chemomechanical caries removal appears sound by normal clinical criteria, no definitive evidence has yet been obtained to confirm that the dentine surface is in fact mineralised. The aim of this study was to use backscattered electron (BSE) imaging and electron probe micro-analysis (EPMA) to ascertain the level of mineralisation of the dentine remaining in cavities prepared by this technique. Carious dentine was removed from carious lesions by means of N-monochloro-DL-2-aminobutyric acid (NMAB) or NMAB containing 2 mol/l urea. Sections of teeth in which caries removal was complete by normal clinical criteria were examined by EPMA and BSE. Dentine adjacent to the pulp was found to be less mineralised than the surrounding dentine. Although the superficial layer of dentine remaining on the cavity floors frequently appeared to have a slightly reduced mineral content, the results clearly indicated that there was no significant difference between this dentine and the underlying sound dentine.