A scanning electron microscopic study of dentinal erosion by final irrigation with EDTA and NaOCl solutions

AIM

The purpose of this in vitro study was to examine dentinal erosion caused by final irrigation with EDTA and NaOCl.

METHODOLOGY

Twenty-five single-rooted human teeth were instrumented with rotary nickel-titanium Series 29 Profile Instruments. The teeth were divided into five groups and subjected to final irrigation as follows: group A, irrigated with 6% NaOCl (3 mL) for 2 min; group B, 15% EDTA (3 mL) for 1 min; group C, 15% EDTA (3 mL) for 1 min, followed by 6% NaOCl (3 mL) for 2 min; group D, 15% EDTA (3 mL) for 3 min and group E, 15% EDTA (3 mL) for 3 min, followed by 6% NaOCl (3 mL) for 2 min. Photomicrographs of dentinal walls were produced using a scanning electron microscope (3000 x) at 1, 3 and 6 mm from the apex. The amount of debris and dentinal tubule diameter were evaluated, and values were statistically analysed using one-way ANOVA and Fisher's PLSD test.

RESULTS

When the root canal was irrigated with 15% EDTA alone, the dentine had a smooth and plane appearance, and dentinal tubule orifices were regular and separated. When the root canal was irrigated with EDTA followed by NaOCL the dentine was eroded and the dentinal tubule orifices were irregular and rough. Dentinal tubule diameter increased to 3.43 +/- 0.23 microm in group C and to 3.93 +/- 0.44 microm in group E. Significant differences were observed between groups B and C, and between groups D and E (P < 0.05). However, more debris was removed by irrigation with EDTA followed by NaOCl than with EDTA alone (P < 0.05).

CONCLUSIONS

Final irrigation with 6% NaOCl accelerates dentinal erosion following treatment with 15% EDTA.

Renal injury caused by intrarenal injection of phenol increases afferent and efferent renal sympathetic nerve activity

Intrarenal injection of phenol in rats causes a persistent elevation in blood pressure (BP) and in norepinephrine (NE) secretion from the posterior hypothalamus (PH), and downregulation of neuronal nitric oxide synthase (nNOS) and interleukin-1beta (IL-1beta) in the PH. These studies suggest that afferent impulses from the kidney to the brain may be responsible for hypertension associated with renal injury. Downregulation of nNOS and IL-1beta, two modulators of sympathetic nervous system (SNS) activity may mediate this activation. In this study we measured the effects of intrarenal phenol injection on peripheral SNS activity by direct renal nerve recording, plasma NE, nNOS, and IL-1beta abundance in the brain. We also determined whether renal denervation or administration of clonidine prevented these effects of phenol. Acutely, the phenol injection increased both afferent and efferent renal sympathetic nerve activity, decreased urinary sodium excretion, and increased plasma NE. Three weeks after the phenol injection, BP and plasma NE remained elevated. Renal denervation and pretreatment with clonidine prevented the increase in BP and plasma NE caused by phenol. Chronic renal injury caused by phenol was associated with decreased abundance of IL-1beta and nNOS in the PH. These studies have shown that a renal injury caused by phenol injection increases BP and central as well as peripheral SNS activity, which persist long after the injury. Renal denervation and antiadrenergic drugs abolish the effects of phenol on BP and plasma NE. Because NO and IL-1beta modulate SNS activity, the stimulatory action of phenol on the SNS could be mediated by downregulation of nNOS and IL-1beta in the brain.

Domestic exposure to formaldehyde significantly increases the risk of asthma in young children

Concern has arisen in recent years about indoor air pollution as a risk factor for asthma. Formaldehyde exposure was examined in relation to asthma among young children (between 6 months and 3 yrs old) in a population-based control study carried out in Perth, Western Australia, between 1997-1999. An association between exposure to formaldehyde and asthma in young children has been suggested. Cases (n=88), whose parents were recruited at Princess Margaret Hospital Accident and Emergency Dept (Perth, Western Australia), were children discharged with asthma as the primary diagnosis. Controls (n=104), who were children in the same age group without asthma diagnosed by a doctor, were identified from birth records through the Health Dept of Western Australia (Perth, Western Australia). Health outcomes for the children were studied using a respiratory questionnaire and skin-prick tests. Formaldehyde, average temperature and relative humidity were measured on two occasions, winter (July-September 1998) and summer (December 1998-March 1999) in the child's bedroom and in the living room. The study found seasonal differences in formaldehyde levels in the children's bedrooms and living rooms with significantly greater formaldehyde exposure during the summer period for case and control subjects. The generalised estimating equation model showed that children exposed to formaldehyde levels of > or = 60 microg x m(-3) are at increased risk of having asthma. The results suggest that domestic exposure to formaldehyde increases the risk of childhood asthma.

Role of dose concentration in biocide efficacy against Pseudomonas aeruginosa biofilms

Pseudomonas aeruginosa entrapped in alginate gel beads to form artificial biofilms resisted killing by chlorine, glutaraldehyde, 2,2-dibromo-3-nitrilopropionamide (DBNPA), and an alkyl dimethyl benzyl ammonium compound (ADBAC). The degree of resistance was quantified by a resistance factor that compared killing times for biofilm and planktonic cells in response to the same concentration of antimicrobial agent. Resistance factors averaged 120 for chlorine, 34 for glutaraldehyde, 29 for DBNPA, and 1900 for ADBAC. In every case, resistance factors decreased with increasing concentration of the antimicrobial agent. An independent analysis of the concentration dependence of the apparent rates of killing of planktonic and biofilm bacteria showed that elevating the treatment concentration increased bacterial killing more in the biofilm than it did in a suspension culture. Calculation of a transport modulus comparing the rates of biocide reaction and diffusion suggested that at least part of the biofilm resistance to chlorine, glutaraldehdye, and DBNPA could be attributed to incomplete or slow penetration of these agents into the biofilm. Time-kill curves were nonlinear for biofilm bacteria in some cases. The shapes of these curves implicated retarded antimicrobial penetration for chlorine and glutaraldehyde and the presence of a tolerant subpopulation for DBNPA and ADBAC. The results indicate that treating biofilms with a concentrated dose of biocide is more effective than using prolonged doses of a lower concentration.

[Disinfection of the skin prior to injections does not influence the incidence of infections; a literature study]

OBJECTIVE

To assess the incidence of infections after subcutaneous, intramuscular or intravenous injections--using sterile needles--with or without prior disinfection of the skin.

METHOD

Literature searches were made in the database Medline from 1966-June 2001, in the databases Picarta, Embase and the Cochrane Library, as well as manually in the reference lists of the collected articles. Original papers in English, Dutch or German were selected.

RESULTS

Four relevant studies were found, generally of poor quality. In these two infections were reported after disinfecting the skin prior to over 2300 injections in 156 patients, and none were reported after not disinfecting the skin prior to over 7000 injections in more than 700 patients.

CONCLUSION

Both disinfection prior to skin injections and omission of disinfection were followed by (almost) no infections.

Evaluation of Glyde File Prep in combination with sodium hypochlorite as a root canal irrigant

The purpose of this study using a scanning electron microscope was to investigate the efficacy of four different irrigation techniques after canal preparation with Profile Ni-Ti rotary instruments. A modified technique for the use of Glyde File Prep is proposed. Forty anterior teeth were divided into four groups, instrumented, and irrigated as follows: physiological solution (group A), 2.5% sodium hypochlorite (group B), 2.5% sodium hypochlorite and Glyde File Prep (group C), and 2.5% sodium hypochlorite and Glyde File Prep applied at the end of the preparation with sterile paper points (group D). After scanning electron microscopic evaluation at three different levels, debris, smear layer, and dentinal tubules were scored. Groups A and B had significantly more smear layer and less open tubules on the canal walls compared with the group C and group D samples. Differences in the mean amount of debris between group A samples and other irrigation regimes were statistically significant.

[Green nail syndrome or chloronychia]

"Green nails" or chloronychia is an infection mostly caused by Pseudomonas ueruginosa but also by other bacterial or fungal contamination. The clinical appearance consists in a typical triad: green discoloration of the nail plate associated with proximal chronic paronychia and disto-lateral onycholysis. Exposition to moist environment, microtraumatisms, oaychotillomania and associated nail diseases such as psoriasis may promote infection by Pseudomonas. Treatment consists in cutting of the detached nail plate, brushing the nail bed with a 2% sodium hypochlorite solution twice daily and eviction of the repeated immersions by wearing cotton and latex gloves.

[A Cochrane review on the umbilical cord care and prevention of infections. Antiseptic solutions are not necessary in developed countries but life-saving in developing countries]

One million newborn infants die every year by bacterial infections, which often have entered the body via the umbilicus. A Cochrane systematic review on "Topical umbilical cord care at birth" by J Zupan and P Garner is reviewed. Zupan and Garner conclude that simply to keep the umbilical cord dry and clean is sufficient for healthy, term neonates in rich countries; disinfectants do not offer any advantage. However, cleaning the umbilical cord with disinfectants may reduce the risk of serious bacterial infections in babies in poor countries or in neonatal wards. Observational studies in poor countries indicate that the life of numerous infants can be saved if pregnant women are vaccinated against tetanus and disinfectants are substituted for harmful cord care traditions. This Cochrane review is credible, but it should be updated and considered tentative since no data on sepsis are included. The search strategy should be better described and observational studies (case control and cohort studies) from poor countries should be included since there are no randomized control trials from these countries.

Topical treatment of digital dermatitis associated with severe heel-horn erosion in a Swedish dairy herd

Two experiments were run in a commercial dairy herd to test the efficacy of topical treatments of digital dermatitis associated with severe heel-horn erosion. In Experiment I, topical treatments with solutions of either glutaraldehyde or oxytetracycline were compared with foot trimming and cleansing alone. After trimming of all feet, one front and one rear foot in each cow were treated with either glutaraldehyde or oxytetracycline (regardless of dermatitis status), while the other feet were used as controls and only trimmed. Two hundred foot records were obtained from 34 Swedish Red and White and 16 Swedish Holstein cows. The proportions (p) of feet cured from digital dermatitis were compared between each group of medically treated feet and the control feet, assuming the feet to be independent observations with respect to curing. Oxytetracycline was significantly more effective than hoof trimming alone (p=0.87 and 0.34, respectively; P<0.001) and than glutaraldehyde (p=0.41; P=0.004). Treatment with glutaraldehyde was no more effective than hoof trimming alone. In Experiment II, a specially designed footbath with two longitudinal compartments was used to study the effectiveness of a solution of acidic ionised copper in preventing or curing digital dermatitis. The footbath--using water in one compartment--was constructed to make within-cow comparisons of treatment efficacy possible. The hoof health of 44 dairy cows (also included in Experiment I) were studied when the animals first were turned out to pasture and at the end of the grazing season (approximately 6 months later). During the grazing season, the cows were walked through the footbath twice daily after milking for a total of 47 days, divided into five separate periods ranging in length from 3 to 16 days. As judged by a two-sample comparison of proportions, a higher proportion of the cows' hind feet that were affected by dermatitis were cured by the copper solution (20/24) than by water alone (12/23). The copper solution had no significant preventive effect on healthy feet.

[Effect of sodium hypochlorite on neuroregulatory systems in acute psychotropic drug poisoning]

The effect of sodium hypochlorite (SHC) on neuroregulatory systems was studied in patients with acute poisoning with psychotropic drugs infused intravenously as components of infusion therapy. Infusion therapy alone or in complex with SHC does not affect the cholinergic system of the organism. The corrective effect of SHC on the sympathetic, serotonin- and histaminergic systems was more pronounced in comparison with infusion therapy and was the most expressed on day 2 after the treatment.

A protocol for evaluation of the role of disinfectants in limiting pathogens and weed moulds in commercial mushroom production

In vitro and in vivo evaluations of the effects of three commercial disinfectants on isolates of Trichoderma harzianum Rifai and Cladobotryum dendroides (Bull) W Gams & Hoozemans were combined in the development of methodologies for realistic assessment of disinfectant performance. 'Environ' and 'Purogene' incorporated into agar media at 50 mg AI litre-1 were effective in totally preventing the mycelial growth of T harzianum and C dendroides isolates, whereas with 'Sudol' a concentration of 500 mg AI litre-1 was required. Evaluation of a model in vivo system was combined with observations on the fungicidal effects of disinfectants. Spore suspensions of T harzianum (Th1), T harzianum (Th2) and C dendroides prepared from culture washings with sterilised distilled water were used as contaminating inoculum. Environ, Sudol and Purogene in aqueous solutions at 1000 mg AI litre-1 were sprayed onto these building structure surfaces before or after artificial contamination with spore suspensions. Re-isolation from surfaces was carried out using agar swabs, which were prepared in visking tubing, applied to treated surfaces and incubated at 25 degrees C for 24, 48, 72 or 96 h. Environ and Purogene were more effective than Sudol in limiting the recovery of Trichoderma spp and C dendroides. All three disinfectants applied 12 h after artificial contamination onto wood, concrete or glazed surfaces were able to reduce the recovery of these isolates more effectively than when they were applied 12 h before artificial contamination. Greater persistence of contamination was noted on the rougher surfaces (wood and concrete) than on the smoother glazed surface. It was concluded in this in vivo evaluation that, in many cases, the protection achieved by the physical nature of the smooth glazed tile surfaces was equivalent to that available from the application of disinfectants, thus highlighting the attention needed to the nature of building surfaces in the structures used in the mushroom industry. The artificial contamination and re-isolation techniques allowed significant comparison between disinfectant materials, timings and surface types. In the in vivo experiments using a single standardised test concentration, the relative fungicidal effects of the disinfectants, which varied in the complexity of their active ingredients, were better discriminated than the effects observed in vitro, although the general trend was similar.

[Clinical evaluation of the ocular safety of Amukine 0.06% solution for local application versus povidone iodine (Bétadine) 5% solution for ocular irrigation) in preoperative antisepsis]

INTRODUCTION

The aim of this monocentric, randomized, comparative, open study was to evaluate the safety of Amukine 0.06% solution (an isotonic hypochloride sodium solution) versus a 5% povidone iodine solution (Bétadine 5% solution for ocular irrigation) in antisepsis before cataract surgery.

MATERIAL AND METHODS

One hundred and thirteen patients, aged between 49 and 90 years, were included and split, after randomization, into two groups: one testing Amukine 0.06%, the other testing a 5% povidone iodine solution. For each group, after local anesthesia, the antiseptic procedure consisted of an antisepsis of periocular teguments followed by an eye antisepsis through the instillation of two drops of the tested product in the conjunctival fornices. The safety evaluation was performed by grading superficial punctate keratitis 24 hours after surgery (slit lamp examination after fluorescein instillation). Conjunctival hyperemia scores by examination of the bulbar conjunctiva before the first instillation, immediately before surgery, and 24 hours after surgery were also compared.

RESULTS

One hundred and seven reports were analyzed. Concerning the presence of corneal superficial punctate keratitis 24 hours after surgery, mean scores were not different (0.27 for the Amukine 0.06% group and 0.38 for the povidone iodine group; p=0.27 Mann Whitney test). The observations did not show a different progression of conjunctival hyperemia depending on the treatment group (p=0.65 (immediately after application) and p=0.52 (after 24 hours); Mann Whitney test).

CONCLUSION

In this study, the ocular safety of Amukine 0.06% solution was not different from a 5% povidone iodine solution. Therefore, Amukine 0.06% is a new interesting approach to surgical antisepsis in ophthalmology and an alternative in case of iodine allergy.

Formation of disinfection by-products in chlorinated swimming pool water

The formation of five volatile disinfection by-products (DBPs: chloroform, bromodichloromethane, chloral hydrate, dichloroacetonitrile, and 1,1,1-trichloropropanone) by the chlorination of the materials of human origin (MHOs: hair, lotion, saliva, skin, and urine) in a swimming pool model system was examined. Chlorination reactions took place with a sufficient supply of chlorine residuals (0.84 mg Cl2/l < total chlorine < 6.0 mg Cl2/l) in 300 ml glass bottles containing either ground water or surface water as a reaction medium at 30 degrees C and pH 7.0, for either 24 or 72 h. A longer reaction period of 72 h or a higher content of organic materials led to the increased formation of DBPs. Of the DBPs formed by the reaction, chloroform was a major compound found in both ground and surface waters. The formation of chloroform and bromodichloromethane per unit total organic carbon (TOC) concentration was suppressed when all types of MHOs were added to the surface water that already contained DBP precursors such as humic substances. However, the formation of dichloroacetonitrile was promoted, probably due to the increased degradation reactions of nitrogen-containing compounds such as urea and proteins of human origin. In conclusion, the materials of swimmers' origin including hair, lotion, saliva, skin, and urine add to the levels of DBPs in swimming pool water, and any mitigation measures such as periodic change of water are needed to protect swimmers from elevated exposures to these compounds.

Formalin instillation for control of rectal hemorrhage in advanced pelvic malignancy: report of two cases

PURPOSE

This article describes the use of intrarectal formalin to treat intractable rectal bleeding from pelvic malignancy.

METHODS

Case reports of two patients with intractable rectal bleeding from pelvic malignancy are described.

RESULTS

In both cases, treatment with intrarectal formalin stopped the rectal bleeding.

CONCLUSION

Formalin instillation into the rectum is an invaluable technique when one is faced with rectal hemorrhage from inoperable pelvic tumors.

[Characteristics of expression of active oxygen forms by blood cells in patients with chronic bronchitis]

AIM

To study generation of active oxygen forms in the whole blood of patients with chronic bronchitis and correction of the detected disorders.

MATERIAL AND METHODS

By means of registration of spontaneous and staphylococcus-induced luminol-dependent chemiluminescence (LDCL) of the whole blood, generation of active oxygen forms in 73 patients with chronic bronchitis (CB) has been studied.

RESULTS

By the intensity of luminescence, all the examinees were divided into two groups. In group 1 LDCL was high, in group 2 LDCL was under the control level. Combined treatment of group 1 patients included inhalations of ceruloplasmin antioxidant. Patients of group 2 were administered sodium hypochlorite that possesses prooxidation properties. Compared to conventional treatment, the above two treatments produced marked positive changes in the studied indices and clinical symptoms.

CONCLUSION

The method of chemiluminescence registration of the whole blood allows validation of pathogenetic therapy of patients with CB and improves outcomes of the treatment.

Effect of sodium hypochlorite and EDTA on mercury released from amalgam

OBJECTIVES

The effect of sodium hypochlorite (NaOCl) and EDTA on mercury released from dental amalgam was assessed in vitro.

STUDY DESIGN

Fifty-six samples of dental amalgam of similar size were prepared and exposed to a 10-mL solution of either 1% NaOCl, 3% NaOCl, 10% EDTA in 1% NaOCl, or 10% EDTA in 3% NaOCl for periods of 20, 40, and 60 minutes. Mercury concentrations in the solutions were measured by using a cold-vapor atomic absorption Mercury Analyzer System, and the differences between the groups were statistically analyzed.

RESULTS

All amalgam samples exposed to 1% NaOCl and 3% NaOCl-either alone or in combination with EDTA-released mercury into the solutions. Mercury release was significantly higher in the test groups than in the EDTA, distilled water, or phosphate buffer controls (P <.001). Increase in the mean concentration levels of mercury in solution was time-dependent and directly related to NaOCl concentration. The addition of EDTA caused a reduction in mercury levels detected in solution, which was more significant in amalgam samples exposed to 1% NaOCl combined with EDTA (P <.001).

CONCLUSIONS

NaOCl solutions commonly used for root canal cleaning and shaping cause mercury release from dental amalgam and may alter its chemo-physical properties as a sealant for root perforations.

Immunotoxicological investigations on rats treated subacutely with dimethoate, As3+ and Hg2+ in combination

Effects of combined exposure with dimethoate (DM), HgCl2 (Hg), and NaAsO2 (As) were investigated following a 28 - day oral exposure in male Wistar rats. In preliminary experiments, the LOEL (Lowest Observed Effect Level) and NOEL (Non Observed Effect Level) doses of the substances were determined using the same experimental system [determination of body weight gain, organ weights of brain, thymus, heart, lung, kidneys, adrenals, spleen, testicles, popliteal lymph node, white blood cell (WBC) and red blood cell (RBC) count, haematocrit (Ht), mean cell volume (MCV) of RBCs, cell content of the femoral bone marrow, IgM-plaque forming cell (PFC) content of the spleen, delayed type hypersensitivity (DTH) reaction] and animal strain. In the combination studies, LOEL dose of DM (28.2 mg/kg) was combined with NOEL doses of the heavy metals ( HgCl2 = 0.40 mg/kg, NaAsO2 = 3.33 mg/kg), and vice versa (DM = 7.04 mg/kg, HgCl2 = 3.20 mg/kg, NaAsO2 = 13.3 mg/kg). In the DM-Hg combinations, significant alterations were found versus the corresponding high- dose internal control in the body weight gain, relative liver and kidney weights, and in the PFC response. When DM was combined with As, interactions were indicated by changes of relative liver weight, MCV value, and the PFC content of the spleen. These results support the theory that the interactions between pesticides and heavy metals may modify the toxic effects of the single substances, and may also change the functional detection limits of the exposure. The changes in the functional detection limits, if they occur, can lead to false-positive and false-negative results in human epidemiological studies.

[Use of sodium hypochlorite and intravascular laser irradiation of blood in complex treatment of emergency surgical patients]

Results of treatment of 50 patients with urgent pathology of organs of the abdominal cavity are presented. Indirect electro-chemical detoxication of blood against the background of the antioxidant protection of organism was applied with the purpose of detoxication. The problems of a possible side effect of the indirect electro-chemical detoxication of blood, the optimum dosage of sodium hypochlorite in the intravenous injection were investigated.

Two-generation reproduction study and immunotoxicity screen in rats dosed with phenol via the drinking water

This study evaluated the potential reproductive toxicity of phenol in a rat two-generation reproduction study, which included additional study endpoints, such as sperm count and motility, developmental landmarks, histological evaluation of suspect target organs (liver, kidneys, spleen, and thymus), weanling reproductive organ weights, and an immunotoxicity screening plaque assay. Phenol was administered to 30 Sprague-Dawley rats/sex/group in the drinking water at concentrations of 0, 200, 1000, or 5000 ppm. Parental (P1) animals were treated for 10 weeks prior to mating, during mating, gestation, lactation, and until sacrifice. The F1 generation (P1 offspring) was treated using a similar regimen, while the F2 generation was not treated. After mating, 10 P1 males/group were evaluated using standard clinical pathology parameters and an immunotoxicity screening plaque assay. Significant reductions in water and food consumption were observed in the 5000-ppm group in both generations; corollary reductions in body weight/body weight gain were also observed. Mating performance and fertility in both generations were similar to controls, and no adverse effects on vaginal cytology or male reproductive function were observed. Vaginal opening and preputial separation were delayed in the 5000-ppm group, and were considered to be secondary to the reduction in F1 body weight. Litter survival of both generations was reduced in the 5000-ppm group. Absolute uterus and prostate weights were decreased in the F1 generation at all dose levels; however, no underlying pathology was observed and there was no functional deficit in reproductive performance. Therefore, these findings were not considered to be adverse. No evidence of immunotoxicity was noted in the 5000-ppm group. The effects noted at the high concentration were presumed to be associated with flavor aversion to phenol in the drinking water. Based on a comprehensive examination of all parameters, the no-observable-adverse-effect level (NOAEL) for reproductive toxicity of phenol administered in drinking water to rats is 1000 ppm. The corresponding daily intake of phenol for an adult rat at the NOAEL of 1000 ppm is equivalent to about 70 mg/kg/day for males and 93 mg/kg/day for females.

Evaluation of donor arm disinfection techniques

BACKGROUND AND OBJECTIVE

To validate a standardized optimal national procedure for donor arm disinfection.

MATERIALS AND METHODS

A direct swabbing and plating technique was used to enumerate bacteria present on the arm pre- and postdisinfection. Twelve donor arm disinfection techniques were evaluated.

RESULTS

The Medi-Flex Adapted method, consisting of a two-stage process with an initial application of isopropyl alcohol followed by tincture of iodine, produced the best arm disinfection. A percentage reduction in bacterial counts of 99.79% (logarithmic reduction of 2.67) was obtained. Postdisinfection, 70% of donors had bacterial counts of zero, and 98% had counts of 10 or less.

CONCLUSION

The Medi-Flex disinfection method offers the English National Blood Service a validated, optimal 'best practice' disinfection technique and should contribute significantly to the reduction in risk of transmission of bacteria by transfusion.