Assessing the efficacy and cost of detergents used in a primary care automated washer disinfector.

Background: Cleaning of re-usable medical devices is a critical control point in the decontamination cycle, although defined end-points of the process are controversial. Objective: Investigate cleaning efficacy and cost of different detergent classes in an automated washer disinfector (AWD) designed for dental practice. Methods: Loads comprised test soiled dental hand instruments in cassettes and extraction forceps. Residual protein assayed using the International standard method (ISO 15883-5:2005) 1% SDS elution with ortho-phthalaldehyde (OPA) or GBox technology (on instrument OPA analysis). Short (60 minutes) and long (97 minutes) AWD cycles were used with four different classes of detergents, tap water and reverse osmosis water. Results: SDS elution analysis (N = 612 instruments) demonstrated four detergents with both wash cycles achieved equivalent cleanliness levels and below a threshold of 200 µg protein/instrument. GBox methodology (N = 575) using UK Department of Health threshold of 5 µg/instrument side demonstrated that tap water performed with the greatest efficacy for all types of instruments and cycle types. Conclusions: Using International standard methodology, different detergent classes had equivalence in cleaning efficacy. Cheaper detergents used in this study performed with similar efficacy to more expensive solutions. Findings emphasise the importance of validating the detergent (type and concentration) for each AWD.

Failure of non-vacuum steam sterilization processes for dental handpieces.

BACKGROUND: Dental handpieces are used in critical and semi-critical operative interventions. Although some dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0.8-2.3 mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions. AIM: To identify the extent of sterilization failure in dental handpieces using a non-vacuum process. METHODS: In-vitro and in-vivo investigations were conducted on widely used UK bench-top steam sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM; dataloggers), chemical indicator (CI), and biological indicator (BI) methods. FINDINGS: All three methods of assessing achievement of sterility within dental handpieces that had been exposed to non-vacuum sterilization conditions demonstrated a significant number of failures [CI: 8/3024 (fails/no. of tests); BI: 15/3024; TM: 56/56] compared to vacuum sterilization conditions (CI: 2/1944; BI: 0/1944; TM: 0/36). The dental handpiece most likely to fail sterilization in the non-vacuum process was the surgical handpiece. Non-vacuum sterilizers located in general dental practice had a higher rate of sterilization failure (CI: 25/1620; BI: 32/1620; TM: 56/56) with no failures in vacuum process. CONCLUSION: Non-vacuum downward/gravity displacement, type N steam sterilizers are an unreliable method for sterilization of dental handpieces in general dental practice. The handpiece most likely to fail sterilization is the type most frequently used for surgical interventions.

Investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non-vacuum or vacuum processes.

BACKGROUND: Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. AIM: To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. METHODS: Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam sterilizers were tested: a non-vacuum benchtop sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop sterilizer (Lisa; W&H, Bürmoos, Austria). Each sterilizer cycle was completed with three handpieces and each cycle in triplicate. FINDINGS: A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0-150 s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15 s equilibration time). The measurement point at the base of the handpiece failed in all test runs (N = 9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. CONCLUSION: Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail.

What Coping Functions are Served when Health Behaviours are Used as Coping Strategies?

The aim was to clarify what coping functions are served by certain health behaviours when used as coping strategies. A preliminary questionnaire was used to identify individuals scoring high on eating (unhealthily), exercise or self- care as a coping strategy. These individuals completed a further questionnaire to elucidate the specific coping functions being served by their eating, exercise or self-care. Principal components analysis produced five coping function variables: Problem Solving, Feeling Better, Avoidance, Time Out and Prevention. Discriminant analysis (coping functions predicting coping strategy group) produced a Prevention with Problem Solving function, on which the exercise and self- care groups were high compared with the eating group; and a Time Out without Problem Solving function, on which the exercise group was high compared with the self- care group, the eating group being intermediate. Thus health behaviours used as coping strategies can serve not only problem-focused, emotion- focused and avoidance functions, but also time out and prevention functions.