Hygienic maintenance of dental handpieces and turbines

The controversy over the effective sterilization and disinfection of dental handpieces has engaged the minds of dentists and researchers for years but has been made even more important with the advent of the HI virus and AIDS. In this article, initiated as a project by the FDI Commission, Prof. Dr. Klaus Bofsmann examines some of the problems and solutions of sterilization of dental equipment.     

Comparison of handpiece asepsis among Ohio dentists: 1991 & 1992

In 1991, we found that 23 percent of Ohio dentists sterilized handpieces between patients and 67 percent flushed handpieces between patients. In this study, we chose to investigate the changes in handpiece asepsis within Ohio dental offices for the twelve-month period ending August, 1992. Sixty-two percent of the 730 offices polled responded to the questionnaire. Offices reporting sterilization of handpieces between patients in 1992 is 80 percent compared to 23 percent in 1991. Sixty-nine percent of offices in the 1992 survey reported that they have changed infection control protocol to include heat sterilization of handpieces between patients while 24 percent report disinfection between patients. Back order of equipment, inadequate number of handpieces and fear of damage is cited by the offices using disinfection as the reasons for not sterilizing handpieces. Flushing handpieces between patients is reported by 83 percent of the offices. Previously, only 67 percent flushed between patients. Anti-retraction valves are present in 69 percent of the water lines. Breakdown of handpieces attributed to sterilization was reported by 45 percent of the offices. Two-hundred and three offices (45 percent) report questions from patients regarding office infection control policies. Infection control awareness of the general population and implementation of these procedures by dental professionals is increasing in Ohio.     

Genomic organization, sequence interrelationship, and physical localization using in situ hybridization of two tandemly repeated DNA sequences in the genus Olea

A decision scheme for determining the capability of a finished product dosage form to be terminally sterilized was presented and followed for a heat-sensitive, oxygen-sensitive drug product (DP). Studies were conducted first in a laboratory steam sterilizer and then in a production unit. When a nonheat-sensitive steam sterilization cycle produced unfavorable loss of potency and increases in the amount of impurities, a new heat-sensitive steam sterilization cycle was investigated. An acceptable product was produced by reducing the headspace oxygen level and reducing the heat delivered to the product during terminal sterilization. The amount of sterilizing steam heat delivered to the product was reduced by reducing the allowable temperature range from set-point of the terminal steam sterilizer, and by developing a new heat-sensitive cycle. The heat-sensitive cycle, with a model based upon a known relationship of the biological indicator, product D value, and the environmental bioburden, can achieve a 10(-6) sterility assurance level when it delivers an F0 > or = 4 min. When the standard terminal sterilization model and cycle produced unacceptable levels of degradation, formulation/production changes, and terminal sterilization model and cycle modifications were explored, before the DP was directed to aseptic filling. Acceptable moist heat terminal sterilization the DP was then achieved.     

Genomic organization of the mouse adrenocorticotropin receptor

PURPOSE: This paper describes the perceived risk of occupationally contracting HIV and reported compliance with universal precaution guidelines among Australian dental hygienists and dentists. METHODS: This examination is based upon responses to a mailed questionnaire from all registered dental hygienists (63% response rate, n = 208) and dentists (76% response rate, n = 550) in Western Australia. RESULTS: Results indicate that: 1) oral healthcare providers who perceive a high risk of occupationally contracting HIV report a more conservative, cautious approach to HIV infection than do providers who perceive less risk of contracting the virus; 2) dental hygienists are more likely than dentists to report a higher degree of perceived risk of occupationally contracting HIV; and 3) dentists are more likely than dental hygienists to report compliance with universal precaution guidelines in the dental practices where they work. CONCLUSION: Educating oral healthcare providers on the realistic risks of occupationally contracting HIV and the value of compliance with universal precaution guidelines may reduce undue stress and hindrances in the provision of safe and effective oral healthcare in this era of AIDS.     

Serum antibodies to secreted proteins in patients infected with Escherichia coli O157 and other VTEC

OBJECTIVES: The purpose of this study was to survey the efficiency of visible light curing units in dental practices across Australia. METHODS: Survey forms were distributed to representatives of 3M Health Care to complete when visiting dentists in their working areas. The information collected included the type and age of the unit, curing times used, history of maintenance, replacement of components, and the light intensity reading. RESULTS: Of the 214 light curing units surveyed, approximately 27% recorded a light intensity of 200 mW cm-2 or less, a level regarded as inadequate to cure a 2-mm thick increment of composite resin. An additional 26% registered an output of between 201 and 399 mW m-2. This level would be considered acceptable with additional curing time; however, 44% of practitioners were curing for 20 s or less. A negative correlation was found between the age of the unit and the intensity recorded. Nearly 50% of respondents had never checked the light output of their unit. CONCLUSIONS: The results indicate that just over one-half of the light curing units surveyed were not functioning satisfactorily. An obvious reduction in intensity was noted with the older units. There is a substantial lack of awareness among dentists of the need for maintenance and regular checking of the light intensity of these units.     

Mechanisms of exercise limitation in chronic heart failure and the role of rehabilitation

The purpose of this study was to determine whether heat sterilization adversely effects the torsional properties of rotary nickel-titanium files, making them more prone to fracture under torsional stress. Nine hundred sizes 2 through 10 Profile Series 29.04 taper files were divided into groups of 10 files each and sterilized 0, 1, 5, or 10 times in the steam autoclave, Statim autoclave, or dry heat sterilizer. Then, they were subjected to torsional testing in a Torquemeter Memocouple. Complete data were collected for sizes 2 through 7, but not for sizes 8 through 10 because their torque resistance exceeded the testing limits of the Torquemeter Memocouple. A one-way analysis of variance was used to compare all experimental groups in sizes 2 through 7 with their unsterilized controls (p < 0.05). Fifty-four comparisons were made for torsional strength and 54 for rotational flexibility. Ten significant changes occurred for torsional strength and 10 for rotational flexibility. Eight of 10 changes in torsional strength were increases. Fifty-two of 54 (96.3%) comparisons for torsional strength and 47 of 54 (87%) for rotational flexibility showed a significant increase or no change. Therefore, heat sterilization of rotary nickel-titanium files up to 10 times does not increase the likelihood of instrument fracture.     

The oral health of Indiana's independent, disabled adults

This epidemiological study was conducted to measure the oral health and related variables of one of Indiana's special population groups: adults who are developmentally disabled, work in sheltered workshops and do not live in staffed residential facilities. Fifteen sheltered workshops in ten Indiana counties cooperated with this study in which 393 individuals were interviewed and received oral screening. Information was gathered regarding oral health status, history of utilization of dental services, availability of dental insurance or Medicaid and use of tobacco products. This study was conducted by the Indiana Foundation of Dentistry for the Handicapped and was funded by the Indiana State Department of Health.     

Assessment of the efficacy of a low temperature hydrogen peroxide gas plasma sterilization system

The STERRAD 100 sterilization system (Johnson & Johnson Medical Ltd) uses low temperature hydrogen peroxide gas plasma for sterilization of heat labile equipment. The efficacy of the machine was tested by contaminating a standard set of instruments with different organisms and using a filtration method to assess recovery of organisms from the wash fluids of instruments post-sterilization. Experiments were performed under clean (the organism only) and dirty (organism mixed with egg protein) conditions. A parallel study conducted using a 3M STERIVAC ethylene oxide sterilizer could not be completed owing to closure of the ethylene oxide plant. For sterilization of instruments with long and narrow lumens, hydrogen peroxide adaptors are necessary. The STERRAD 100 sterilizer can achieve effective sterilization of heat labile instruments with a reduction of 6 log10 cfu/mL of organisms tested. This method has the advantages over ethylene oxide sterilization of safety, ease of maintenance and no requirement for aeration time.     

Acute fluoride ingestion: recognition and management

Occasionally, the Oral Health Division of the Indiana State Department of Health receives inquiries regarding diagnosis and treatment of acute fluoride ingestion. Because a wide variety of fluoride preparations are available in the dental setting and over the counter, excessive ingestion of fluoride can occur if these products are not used properly. The following article is meant to be a quick and easy guide in the recognition and management of instances of acute fluoride ingestion.     

The effect of non-protein food constituents on the nutritive value of radiation-sterilized casein

The effect of radiation sterilization on casein alone and in the presence of glucose or starch was assessed by means of nitrogen balance studies in growing rats and compared to the effect of heat sterilization. No decrease in protein digestibility and utilization was noticed in the irradiated samples nor did the presence of glucose or starch during processing cause and changes of these parameters. Following heat sterilization of casein in the presence of glucose there was a significant reduction in protein digestibility and Net Protein Utilization (NPU). These changes were accompanied by a drastic decline of available lysine. The inclusion of 3% agar-agar (aqueous solution) in the diet induced a drastic rise in endogenous faecal nitrogen losses and a corresponding decrease in apparent protein digestibility and NPU.     

The role of volume contraction in the hypocalciuric action of chlorothiazide

Regarding to ignorance of germ thermoresistance occurring in hospital environment, the effect of sterilization in medicine is determined occasionally on samples of medium with high number of germs or tests are performed to determine the sterilization success (in pharmacy) by examining samples of sterile badges, although their degrees of contamination (mostly low) before sterilization are not known. Instead of fixed sterilization parameters, the new second Pharmacopoeia of the German Democratic Republic (1976 seqq.) allows a free choise of sterilization parameters ingeniously spaced (110 degrees C--140 degrees C vapour, 160 degrees C--200 degrees C hot air) according to diagrams. The mentioned methods both imperfect and expensive ones should be replaced by introducing sterilization indicators whose changes might render the designation "sterile" possible. Substantial differencies between biological and chemical indicators are shown.     

HIV antibody testing in a teaching hospital: policy versus practice

The cost of HIV antibody testing can be phenomenal. Thus many countries, Ghana included, have adopted policies to guide physicians in making judicious test requests. An analysis of compliance with this policy in a teaching hospital in Ghana, shows that 70% of physician requests meet the stated Ministry of Health guidelines. However, while 84.5% of all test requests which turned positive were within stated guidelines, 48.6% of those turning out negative were not indicated by the policy. The cost of HIV antibody testing could be minimised if clinicians operated within the stated guidelines which make considerations for judicious use of health resources. Compliance with policy also needs evaluating.     

Intracellular fluorescence polarization measurements by the Cellscan system: detection of cellular activity in autoimmune disorders

BACKGROUND: Sodium retention is often a precursor to hospitalization in people with heart failure (HF). Lack of compliance with medications and with dietary sodium restrictions affects sodium retention. OBJECTIVES: The purpose of this study was to evaluate the reliability and validity of the Beliefs about Medication Compliance Scale and the Beliefs about Dietary Compliance Scale. METHODS: The Beliefs about Medication Compliance Scale and the Beliefs about Dietary Compliance Scale are instruments we developed specifically to measure beliefs about compliance with behaviors that affect sodium retention in persons with HF. The scales, based on the Health Belief Model, were designed from a review of literature and from self-reports of people with HF. A convenience sample of 101 people with HF completed the scales. RESULTS: Internal consistency reliability was satisfactory. Factor analysis provided initial support for construct validity of the scales. CONCLUSIONS: Future testing of the scales is needed in more diverse populations. The scales can then be used to test interventions tailored to individual subjects' beliefs about compliance.     

Overview of polyethylene as a bearing material: comparison of sterilization methods

Polyethylene has been used for more than 30 years as an orthopaedic bearing material; however, there has been recent concern regarding the early failure of a small percentage of the polyethylene bearings. The damage seen in some retrieved polyethylene components has been linked to gamma radiation sterilization in air, which was widely used by the industry for years. Gamma radiation in air has been documented to cause an increase in oxidation and degradation of mechanical properties with time. The degradation of polyethylene initiated by gamma sterilization in air has led the orthopaedic industry toward alternative sterilization methods, including gamma radiation in an inert gas or vacuum environment, ethylene oxide gas sterilization, and gas plasma sterilization. For many of these alternative techniques, little clinical performance data exist. This study is a comparative evaluation of sterilization methods using the same analytic techniques that have been used to document the effects of gamma sterilization in air on polyethylene. Fourier transform infrared spectroscopy, electron spin resonance, and uniaxial tensile testing are used to compare, respectively, the oxidation levels, free radical concentration, and mechanical properties of material sterilized by each method. The polyethylene is evaluated before sterilization, poststerilization, and postartificial aging. All examined alternative sterilization methods, when compared with gamma sterilization in air, caused less material degradation during a component's preimplantation shelf life.     

Microbial contamination of dental units and ultrasonic scalers

Microbial contamination of the water system in 12 dental units and nine ultrasonic scalers was investigated. Water samples from ultrasonic scalers, high-speed handpieces and water syringe lines showed microbial concentrations of up to 2.6 million, 3.3 million and 190,000 colony forming units/ml respectively. Flushing the lines for 2 minutes reduced the microbial levels, but complete elimination of all bacteria was not achieved. The infectious potential of contaminated water, to the dentists and patients, particularly the compromised host is discussed.     

Practical experiences with sexual sterilization following directives of the Ministry of Health 5/72, Codex paragraphy 27, law 20/66

In 1975, 35 women were administered artificial sterilizations using the Pomeroy technique, 6 for health reasons and 29 for socioeconomic reasons. All patients had already experienced 5 or more births and rejected any proposed contraceptives. Protocol for the operation under the sterilization law includes the patients nationality, IQ, reason for sterilization, and recommendations of the local board of Social Health. Sterilizations took place 1-2 days after birth, using general anesthesia and lasting approximately 15 minutes. Of the 29 women administered the operation for other than medical reasons, none experienced either early or late complications.     

Dental Health Center 2000

The Dental Health Center concept is proposed as a method to maintain control of the dental delivery system while delegating the dentist's managerial and supervisory responsibilities to well-trained business executives. The Center would be a uniquely designed facility that operates 12 hours per day, 6 days a week for 50 weeks of the year. The participating dentists relocate their practices to the facility at a practice purchase price determined by the dentist, paid half in cash and half in center stock. In return, the dentists agree to produce that practice purchase price annually; in turn, they receive 45 percent of their monthly collected dental service fees and have access to all the services of the Center.     

For a healthier community

The ability to sterilize endodontic files inserted into synthetic sponges was tested. Sponges were subjected to 5 cycles of either dry heat (Driclave) or steam under pressure (autoclave) sterilization. Sterilization was corroborated by microbiological tests. The sponges and files were pre-sterilized separately using steam under pressure. One hundred eighty files contaminated with Bacillus stearothermophilus spores (experimental and positive control) and 60 noncontaminated files (negative control), were inserted into 60 sponges. After each cycle, each file and a portion of sponge surrounding the file were transferred aseptically to tubes containing trypticase soy broth culture medium for bacteriological analysis. None of the tubes containing files and portions of sponges that were subjected to autoclave grew Bacillus stearothermophilus spores. Two of 60 (3.33%) of the tubes that were subjected to sterilization by Driclave demonstrated bacterial growth. Although the sponges tolerated the dry heat cycles well physically, sterilization was achieved in only 96.67% of the cases.     

The relationship of the changing structure of families and the health of children

The changing family structure impacts on the physical and mental health, emotional state and academic performance of children. Children reared in other than a family with both biological parents have increased difficulties. Pediatric dentists will need to consider these realities in their treatment of an increasing diverse population of children.     

An experimental test of adolescents' compliance with dental appointments

This study assessed factors associated with adolescents' compliance with dental appointments. Patients (n = 162) attending an adolescent clinic were administered a pretest questionnaire assessing health locus of control, self-esteem, and beliefs and attitudes about dental health from the Health Belief Model. Adolescents needing dental care were randomly assigned to groups for whom their dental appointment was made by a health professional or one in which the patient made his or her own appointment and to groups receiving an appointment reminder card versus not receiving a reminder card. Dental records were then reviewed to examine previous experiences with dental treatment. Neither the method used for making the appointment nor the use of reminder cards had a significant effect on compliance with the dental appointments. Also, compliance was not associated with health locus of control, self-esteem, or variables from the Health Belief Model. Older patients were more noncompliant than younger patients (tau = 0.14). Noncompliance was negatively correlated with the number of previous dental visits and previous dental procedures, oral hygiene instruction, and x-rays. Number of previous x-rays and previous broken appointments explained 5.1% of the variation in noncompliance. The Health Belief Model was not successful in predicting compliance behavior in this sample of adolescents.