Outcome of sterilization by steam autoclaves in Danish dental offices

Abstract — The aims of this study were to evaluate the performance of autoclaves and the use of biologic indicators for sterilization control, and to look for predictor variables for improperly functioning autoclaves in Danish dental offices. The study population comprised 314 Danish dental offices (participation rate 94%); 177 from the public Child Dental Service (CDS) and 137 from private practice. A minor questionnaire and five biologic indicators, (Attest Biological Indicator for Steam Sterilization, 3M) were sent to the participants. CDS offices were found more inclined to use biologic indicators than PP offices ( P <0.00001). Among CDS autoclaves 2.3% (95% confidence limit: 0.9–5.7%) failed to sterilize compared to 7.3% (95% confidence limit: 4.0–12.9) of the PP autoclaves. This difference is not statistically significant, but the confidence intervals indicate a possible true difference in favor of a better outcome in the CDS offices. Looking at the whole sample no other predictor variable for inadequate sterilization could be determined as differences were statistically insignificant with regard to years of professional experience, age and brand of autoclave, and use of biological control. Recommendations from an official body stating the approved types of sterilization control in dental offices would be of value.     

Antibody to human papilloma virus in Danish dentists

Abstract — The aim of this study was to investigate the seroprevalence of antibody to human papilloma virus (HPV) among Danish dentists in order to determine whether this virus constitutes an occupational hazard for dentists. Serum samples from 452 Danish dentists were tested for antibody against a common capsid antigen to HPV by a complement fixation reaction. Nine (2.0%) were seropositive. Dentists'odds ratio for seropositivity was after adjustment for age 0.6 (90% confidence interval: 0.3–1.4) compared to that of voluntary blood donors. In conclusion, Danish dentists do not seem to be at an increased risk of becoming infected with HPV.     

Localization of foetal antigen 2 (FA-2) in foetal and adult human skin

Foetal antigen 2 (FA-2) is a connective-tissue-associated antigen isolated from second trimester human amniotic fluid. FA-2 has an alpha-electrophoretic mobility and is a single-chain molecule with a molecular weight of 26 kDa as determined by polyacrylamide gel electrophoresis (PAGE). Using indirect immunofluorescence and the immunoperoxidase technique, FA-2 was found to be in the lamina densa/sublamina densa region of the basement membrane zone (BMZ) in adult as well as in foetal skin. FA-2 was found throughout the dermis in foetal skin, whereas in adult skin it was found to be associated with the BMZ and around the blood vessels, hair follicles and eccrine glands. Intracellular FA-2 antigen was demonstrated in proliferating fibroblasts by the indirect immunoperoxidase technique and immunoelectron microscopy of the fibroblasts revealed staining of the antigen in the cisternae of the rough endoplasmatic reticulum at the trans-side of the Golgi complex as well as in vesicles close to the plasma membranes. FA-2, a hitherto undescribed antigen associated with human BMZ, is probably being synthesized by proliferating fibroblasts.     

Oncogenic Potential of Inhaled Hydrazine in the Nose of Rats and Hamsters after 1 or 10 1-hr Exposures

Hydrazine (N₂H₄) is used as a fuel for missiles and standbypower systems of operational military aircraft. Maintenanceof missiles and aircraft may result in accidental human exposureto high concentrations for brief periods of time. The purposesof this study were to assess the oncogenic potential of N₂H₄in rats and male hamsters exposed to a high concentration ofN₂H₄ for repeated short exposures and to investigate the relationshipsof acute and subchronic effects of N₂H₄ to nasal tumorigenesis.In Phase 1 (acute and subchronic) and Phase 2 (lifetime) experiments,groups of male and female Fischer 344 rats and male Syrian goldenhamsters were exposed by inhalation to 0,75 (Phase 2 only),or 750 ppm N for 1 (acute) or 10 (subchronic) 1-hr weekly exposures.Rodents were euthanized 24 hr after exposures 1 and 10 and 24to 30 months poststudy initiation. Significant reductions inbody weight were observed in N₂H₄-treated rodents compared tocontrols during the exposure interval. No hydrazine-inducedmortality was detected. Histopathologlc examination after theacute and subchronic exposures revealed degeneration and necrosisof transi tional, respiratory, and olfactory epithelia in theanterior nose and, in rats exposed subchronically, squamousmetaplasia of the transitional epithelium. Minimal to mild rhinitisresulted from N exposures. Apoptosis was observed in olfactoryand squamous metaplastic transitional epithelium. Lesions occurredat sites reportedly having high air-flow and generally appearedto be more severe In the anterior portion of the nose. By 24months, the squamous metaplastic transitional epithelium revertedback to normal-appearing transitional epithelium. By 24+ months,low incidences (sexes combined) of hyperplasia (5/194 2.6%)and neoplasia (11/194 5.7%) were detected, principally in thetransitional epithe hum of the 750 ppm N₂H₄-treated rats. Asimilar incidence of hyperplasia (2/94 2%) and neoplasia (5/945.3%) was detected in the high-exposure group of hamsters. Thelocation and type of N₂H₄-induced proliferative lesions weresimilar to those reported in a chronic N₂H₄-exposure study (5.0ppm x 6 hr/day x 5 days/week for 1 year) conducted in our laboratory,but the chronic study had much higher incidences (rats, sexescombined: hyperplasia 15.5% vs 2.6% and polypoid adenoma 44.6%vs 5.2%). The product (CD) of concentration x time was the same(7500 ppm hours) for the high-dose groups for both studies,but the duration of exposure was 150x longer and the concentrationwas 150x lower in the chronic study. These comparisons suggestthat the duration of exposure is a more significant factor thanconcentration in N₂H₄-induced nasal tumorigenesis.     

Stereological quantification of tumor volume,mean nuclear volume and total number of melanoma cells correlated with morbidity and mortality

Stereological quantification of tumor volume, total number of tumor cells and mean nuclear volume provides unbiased data, regardless of the three‐dimensional shape of the melanocytic lesion. The aim of the present study was to investigate whether these variables are reproducible and may represent potential indicators of prognosis. Sixty patients who underwent surgery at the Department of Plastic Surgery, Aarhus University Hospital, from 1991 to 1994 were included in the study. Total tumor volume was estimated by the Cavalieri technique, total number of tumor cells by the optical dissector principle, and nuclear mean volume by point counting. Tumor volume, total number of tumor cells and nuclear mean volume were all reproducible parameters, showing a non‐significant intra‐observer variation (p=0.72; p=0.83, and p=0.15). Grouped according to the median values, the disease‐free survival time was significantly different for tumor volume as well as total number of tumor cells (p=0.0006 and p=0.0004), but no significant difference in mortality was found (p=0.1 and p=0.06). The mean nuclear volume showed no difference regarding disease‐free survival or mortality (p=0.5 and p=0.8). Breslow's thickness showed a significant impact on both disease‐free survival (p=0.001) and mortality (p=0.009). In conclusion, tumor volume and total number of cancer cells were highly reproducible but did not add additional, independent prognostic information regarding the study population.     

Comparative bone morphometric analysis of mandibles and iliac crests

Abstract – A comparative analysis of bone mass in the mandible and the iliac crest has been carried out in autopsy specimens from 30 subjects aged 23–84 years. Microradiograms of standardized 100-μm-thick sections of the undemineralized plastic embedded material from the two locations were used for quantitation. The following measurements were carried out by electronic point-counting: 1) the percentage of cortical bone mass in the subperiosteal and subendosteal layers, 2) mean cortical width, and 3) the percentage of trabecular bone mass in die iliac crest. Positive correlations were found in the expressions of bone mass within the mandible; the values were significantly higher in the 200-μm-thick subperiosteal layer than in the remaining part of the mandibular cortex. Only a poor or no correlation was found in the expressions of bone mass from the two sites. The investigation, therefore, shows that bone mass and cortical width in the mandible cannot be predicted from a biopsy from the iliac crest. This finding may partly be due to different age-dependent functional changes of the two bones.     

Anxiety and dental fear in a group of parenteral drug addicts

Abstract — The aim of the study was to evaluate whether general anxiety and dental anxiety were more common in a group of parenteral drug addicts. 41 drug addicts =27.4 yr) attending a dental clinic in Aarhus in Denmark participated. A randomly sampled reference group comprising 350 individuals living in Aarhus and with similar age distribution was selected from the Central Person Register. Questionnaires with social and educational data and three self-report rating scales, namely Corah's dental anxiety scale (CDAS) and Spielberger's State-Trait anxiety inventory's two scales (STAI-State and STAI-Trait) were completed by the participants. Response rates were 95.6% and 89.3% for drug addicts and controls, respectively. Median CDAS, STAI-State, and STAI-Trait were 10, 46 and 44 in the addicts which was statistically significantly higher than in the general population. These differences were still present when the addicts were compared to a subsample from the reference group with a better matching of educational and social background factors. Spearman's correlation coefficient between CDAS and STAI-State, CDAS and STAI-Trait, and STAI-State and STAI-Trait were 0,57, 0.49 and 0.50, respectively, which were significant and moderately high correlations. Finally, anxiety levels were similar irrespective of caries experience.     

Normal Myocardial Enzymes and Normal Echocardiographic Findings During Noninvasive Transcutaneous Pacing

Noninvasive transcutaneous pacing was performed for 30 minutes in 10 healthy volunteers. The pace rate was from 85 to 115 min-1, and the threshold for pacing was from 38 to 70 mA, median 59 mA. Echocardiography before and during pacing showed no changes in left ventricular end-diastolic diameter, in fractional shortening nor in contraction pattern. Also, blood pressure remained unchanged. Blood samples for determination of myoglobin, creatine phosphokinase, creatine kinase MB and lactate dehydrogenase were drawn prior to pacing and 1,2,3,4,6,8 and 24 hours after pacing. The serum concentrations were the same before and after pacing for all enzymes and myoglobin. We conclude that non-invasive transcutaneous pacing for 30 minutes causes no muscular or myocardial injury and that the left ventricular function remains normal.