A. Enrique Acosta-Gío

Caries risk assessment from dental plaque and salivary Streptococcus mutans counts on two culture media

This study attempted to determine which combination of plaque or saliva, and tryptic soy agar, bacitracin (TSY20B) or mitis salivarius, bacitracin media, yielded the highest caries-predictive values for mutans counts in children with different caries prevalence. Sixty children were divided into three equally sized groups: caries free, low caries and high caries. Eighteen months later, their caries incidence and initial mutans count were compared. Fissure plaque on TSY20B yielded a high correlation between mutans counts and caries prevalence (P<0.009, r=3346) and incidence (P<0.003, r=4521). The caries-predictive values obtained demonstrate that the coefficient of variation of mutans counts from lower first-molar fissure plaque on TSY20B accounts for 20.4% of the variation in final caries index. This strong correlation provides a valuable tool for the identification of caries-prone individuals.

Instrument processing with lauryl dimethyl benzyl ammonium bromide: A challenge for patient safety

The quaternary ammonium compound (QUAT) lauryl dimethyl benzyl ammonium bromide (LDBAB) is commercialized in the Caribbean, Central, and South America under label claims to sterilize medical and dental instruments in 30 minutes or less. But QUAT formulations are classified as low-level disinfectants with no sporicidal activity or tuberculocidal efficacy. This study evaluated the presumptive sporicidal and tuberculocidal activities of 2 LDBAB formulations with label claims of high-level disinfectant action used widely in the Americas. In this study, sporicidal activity was evaluated against a challenge inoculum of 10(6)Bacillus atrophaeus spores. Tuberculocidal activity was evaluated against Mycobacterium tuberculosis H37Rv using the quantitative suspension test described in European Standard EN14348:2005. Tested at the recommended product concentrations indicated on their respective labels, both LDBAB solutions failed to demonstrate sporicidal activity and tuberculocidal efficacy. These findings underscore the need for public health authorities, as well as medical and dental professionals, to correctly identify LDBAB as a low-level disinfectant and avoid its use in instrument processing, a practice that may endanger lives.

Biological verification of sterilization cycles in dental clinics in Mexico

We read with great interest the recent report by Patino-Marin et al1 on the biological verification of sterilization cycles (BVSC) in San Luis Potosi, Mexico.We agree that BVSC is important as a routine component of infection prevention and control. As the authors point out, in 2002 we reported failures in 242 of 3,277 tests (7.4%), with convection dry heat failing with greater frequency (10.2%).2 Over 19 years, we received tests from 113 dental clinics nationwide, withmost participant dentists inMexico City. Participant dental clinics used 129 different devices (97 autoclaves, 28 convection dryheat ovens, 3 chemical vapor, and 1 rapid dry-heat). Of 7383 cycles—with in-use dental instrument loads—we detected 753 sterilization failures (10.2%) (Table 1). For the autoclaves, the observed failures were less than expected. No inferences can be made on any type of sterilization equipment because of the diversity of brands and models used as well as rotation of personnel charged with operating the equipment. It is noteworthy that in the study by Patino-Marin et al,1 participants’ responses to a questionnaire reveal autoclave misuse: “140°C, 31 minutes, 19 psi.” Apparently, many dentists among the participants ignore appropriate cycle parameters and fail to read the equipment’s thermometer and pressure indicator dial. In general, autoclaves, calibrated at sea level, work at 132°C-134°C and 2 kg/cm2 (274°F and 30 lb/in2) or 121°C and 1 kg/cm2 (250°F and 15 lb/in2). Because of diversity in autoclave design and performance, the manufacturer’s written instructions must always be followed for each particular model and load configuration. The mandatory use of BVSC remains unknown to most dentists in Mexico. We agree with Patino-Marin et al1 that there is a need to disseminate information on infection control. Health authorities, schools of dentistry, professional associations, and industrymust support education efforts to help improve patient safety in dental clinics in Mexico.