[ combined effect of lysozyme and zataria multiflora essential oil on vibrio parahaemolyticus]

Various studies have been conducted to show the effects of essences and enzymes on foodborne pathogens in culture media. The aim of this study was to determine the effect of Zataria multiflora Boiss. essential oil and lysozyme alone and in combination on preventing growth of Vibrio parahaemolyticus in culture media. In this study, the MIC of Zataria multiflora Boiss. essential oil and lysozyme, together and alone, on Vibrio parahaemolyticus, was determined by using macro and microdilution methods. The MIC of Zataria multiflora essential oil determined 0.01% and 0.02% by using macro and microdilution methods, respectively and lysozyme at 1000 mg/mL concentration could not inhibit the growth of V. parahaemolyticus. According to the results of current study, Zataria multiflora essential oil showed better results in comparison with lysozyme, moreover Applying lysozyme and essential oil together did not decrease MIC, but extended the latent phase of V. parahaemolyticus, which considered an important factor in microbiology

[First detection of Sarcocystis hirsuta from cattle in Iran]

Although the high infection rate of microscopic sarcocyst occurs in cattle, to the best of our knowledge, there is no report about the identification of macroscopic sarcocyst in Iran. In this work, Sarcosystis hirsuta was first isolated from slaughtered cattle. In a 2-year-old slaughtered cattle, morphological examination revealed 3-5 mm in length cysts distributed in different striated muscles, particularly intercostalis and diaphragm. In electron microscopy study, ultramicroscopic structure of primary cyst wall based on the presence of cone-shaped villar protrusions confirmed the occurrence of S. hirsute

[Comparison of human papilloma virus genotypes in patient with leukoplakia and mild dysplasia and health persons by polymerase chain reaction]

Early detection of malignant and dysplastic lesions has been an aim for clinicians. Although leukoplakia is not associated with any special hystopathologic diagnosis, it is considered as a premalignant or precancerous lesion. Human Papilloma virus especially HPV16 and HPV18 has been detected in many oral leukoplakia lesions. The aim of this study is to evaluate the presence of HPV and its genotypes 11, 16, 18, 30s and 50s in common leukoplakia, oral hairy leukoplakia, mild dysplasia and compare it with healthy mucosa. Ten samples of each lesion were prepared and fixed in paraffin blocks. After DNA isolation, PCR was done by chelex-100 method. The results were analyzed by SPSS statistical software, Chi-Square and Fisher's Exact test with P Value of 0.05. Seven out of 10 common leukoplakia and OHL, 1 out of mild dysplasia and healthy mucosa were HPV+. Double comparison by Fisher exact revealed that there was a significant difference in frequency distribution of HPV between OHL and healthy mucosa [p=0./01] and also between OHL and Mild dysplasia[p=0./01].The difference between frequency distribution of HPV and of common leukoplakia and healthy mucosa[p=0./01],also between common leukoplakia and mild dysplasia [p=0./01] was significant, the difference between other groups was not significant. Results of the study suggest that there is no significant correlation between infection of HPV subtypes in the evaluated lesions. In other words, no significant relationship was shown between the infection of special subtype of HPV and common leukoplakia, OHL and mild dysplasia. According to the findings of this study, HPV probably has a role in the pathogenesis of leukoplakia.To investigate the role of various subtypes of this virus in leukoplakia lesions, further studies with more samples are needed

Prevalence of Musculoskeletal disorders and it's risk factors among, mothers' home working

Background: Musculoskeletal disorders are one of the most important occupational health issues in the world

Materials and methods: This cross-sectional study was conducted on 333 stay-at-home working mothers. We used modified Nordic questionnaire for this study. Data was collected by trained interviewers

Results: The most common musculoskeletal disorders were in the low back [49.5%], neck [24.1%], and shoulder [21.2%] areas. The results showed that there were significant relationships between low back and knee pain and BMI [p=0.008], between shoulder pain and laundry method [p=0.04], between leg pain and house cleaning method [p=0.01], and between knee pain and use of stairways [p=0.004]

Conclusion: There is a significant relationship between musculoskeletal disorders and the use of various devices in household chores. More research is recommended to clearly identify the correlates of musculoskeletal disorders

[Development and evaluation of antioxidant chitosan film incorporated with grape seed extract]

The application of antioxidant films is a promising strategy for controlling chemical spoilage of food. Antioxidant chitosan films incorporated with grape seed extract [GSE] were developed with the objectives of investigation of their characteristics. Chitosan film was developed by casting method and the effect of different concentrations of GSE [0, 0.5, 1 and 2%] on mechanical, color [accordance with hunter system [L* [luminosity], alpha* [redness], and b* [yellowness]], antioxidant characteristics, total phenol [TP], and swelling index [%SI] of films were evaluated. Generally, the tensile strength of GSE formulated films was influenced by the concentrations of GSE. The 2% GSE/ chitosan films revealed tensile strength similar to unsupplemented film. Concerning color of chitosan film, results indicated that by incorporating GSE, significant changes on L*, alpha*, b* values were appeared [p 0.05]. The antioxidant activity of GSE formulated films was considerable due to the high source of phenolics. This activity was affected by GSE concentrations, which were significant for film containing 0.5% [37.85%] 1% [39.16%] and 2% [41.57%] GSE in comparison with control [12.34%] [p 0.05]. The results also revealed that by increasing the amount of GSE, the TP and%SI were significantly increased. The results indicated that all characteristics of films were influenced by the extent of GSE. Improvement in antioxidant and total phenol of GSE assimilated films is appreciated. Such films are suitable for handle in preserving food

Trends in prevalent injuries among Iranian pilgrims in Hajj

Annually millions of Muslims depart to Saudi Arabia for performing a religious pilgrimage called "Hajj". In this ceremony, pilgrims face numerous health hazards and injuries such as pressing in overcrowding, sliding, burning, falling down, traffic accidents etc. The main purpose of this study was to determine the prevalence of injuries in Hajj period across 2004 to 2008. This study was conducted on 253808 Iranian pilgrims on five consecutive years of Hajj ceremonies, from 2004 to 2008. We used a report sheet with 13 types of injuries and 13 mechanisms of these injuries. SPSS V13.5 soft ware was used for analyzing the data. ANOVA and independent sample t- test was conducted, and relationships were considered significant at P< 0.05. The most common injuries was "tissue contusions and ruptures "[about 76/10000], and "tendon lesions" [about 62/10000]. In addition, the most common mechanism of injuries was "ankle sprain" [69/10000] during the five consecutive years. The prevalence of all fractures was about 49/10000 and the proportion of burning with hot water or fire was about 40/10000. Changes of all causes of the injuries were significant in this study [P< 0.05]. We have suggested some directions for preventing of injuries and related Injuries in Hajj, in this study

Protective effects of aqueous and ethanolic extracts of Nigella sativa L. and Portulaca oleracea L. on free radical induced hemolysis of RBCs

It has been shown that Nigella sativa L. and Portulaca oleracea L. have many antioxidant components. In the present study, the cytoprotective effect of ethanolic and aqueous extracts of N.sativa and P.oleracea against hemolytic damages induced by free radical initiator, AAPH [2, 2' azobis [2-amidinopropane] hydrochloride] was evaluated. Hemolysis was induced by addition of AAPH. To study the cytoprotective effect, aqueous [50, 200, 300, 400, 800 micro g/ml] and ethanolic [25, 100, 150, 200 and 400 micro g/ml] extracts of N. sativa and aqueous [25, 50, 100, 150, 200 and 400 micro g/ml] and ethanolic [300, 600, 900, 1200 and 1800 micro g/ml] extracts of P. oleracea were employed. RBCs were incubated with both extracts and AAPH at 37 °C for 6 hrs. In order to evaluate the impact of the time of addition, extracts were added one and 2 hrs after AAPH. Samples of suspensions were removed at different times and the degree of hemolysis was assessed spectrophotometrically by reading the absorption of supernatants at 540 nm. Aqueous [300, 400 and 800 micro g/ml] and ethanolic [150, 200 and 400 micro g/ml] extracts of N.sativa and also, aqueous [100, 150, 200 and 400 micro g/ml] and ethanolic [1200, 1800 micro g/ml] extracts of P.oleracea showed concentration-dependent cytoprotective effects. Addition of extracts one hour after AAPH reduced but did not eliminate protective activities of extracts. Cytorotective effect of aqueous and ethanolic extracts of N. sativa and P. oleracea against AAPH-induced hemolysis may be related to antioxidant properties of these plants

Epidemiology of herpes human virus 6 and epstein-bar virus infections in salivary gland neoplasms in Isfahan, Iran

Viral infections were reported to be the cause of some human malignancies. The exclusive presence of EBV [Epstein-Bar virus] and HHV6 [Herpes Human Virus 6] has been investigated in previous studies. As such comparisons had never been carried out on salivary gland neoplasms, this study aimed to determine any relationship between these two viruses in salivary gland neoplasms. Seventy eight formalin-fixed paraffin embedded tissue samples of salivary gland tumors were enrolled. The enrolled patients were those who referred to the Department of Oral Pathology of Isfahan University of Medical Sciences and to the state hospitals and private clinics in Isfahan, Iran from May 1995 to July 2005. The paraffin blocks were investigated for presence of HHV6 and EBV genomes by PCR. Out of the 78 samples, 15 were positive for both EBV and HHV6 infections while 6 were only positive for EBV, 21 were HHV6 positive but negative for EBV and 36 samples were reported negative for both viruses. A relationship was visible between EBV and HHV6 genomes. The significant relationship between HHV6 and EBV genomes and salivary gland neoplasms denotes to the question that should be answered in the light of further research whether HHV6 infection in salivary gland tumors can increase the incidence of EBV infection

prevalence of musculoskeletal disorders in health- treatment employees at sabzevar university of medical sciences, iran in 2008

Background and Purpose: Musculoskeletal disorders among the most important occupational health issues nowadays. As the ministry of health is responsible for the community health and providing better services requires healthy workforce, the present study was conducted to determine the prevalence of musculoskeletal disorders in health-treatment employees at Sabzevar University of Medical Sciences, Iran in 2008

Methods and Materials: This cross-sectional descriptive analytical study was conducted on 364 personnel of health treatment employees at Sabzevar University of Medical Sciences, Iran in 2008, who were selected through convenient sampling. The disorders were investigated through Nordik Questionnaire including those in 9 body parts within the past week, past year, and falling behind work due to disorders. The obtained data were analyzed in SPSS 13 using independent test and correlation coefficient.

Results: Mean +/- SD and employment period of the participants were 31.81?6.?? and 9.36?7 respectively. The highest prevalence of the past year in all participants was related to their waist [57.8%], knee [44%] and [42.6%]. However, in participants working for treatment centers, the figures were 61.6%, 46.9% and 48.6% respectively. In the paramedical employees, disorders of was 29.7% and in health center employees, wrist disorders were 28.4%

Conclusion: The prevalence of disorders in university employees is high and the highest rates are related to waist and knee. Disorders of back, waist, knee in the treatment and center employees, and neck disorders in health center employees were higher

[ study on cryptosporidium contamination in lettuce collected from different areas in Shiraz]

Cryptosporidium, a zoonotic parasite with various hosts, is well recognized as pathogen in humans, particularly those with immune-suppression or immune-deficiency. The epidemiologic considerations for cryptosporidiosis emphasize on transmission of resistant oocystes via drinking water, vegetables, food, etc. The present study was undertaken to study the Cryptosporidium contamination in lettuce from different regions as a source of infection for human beings in Shiraz. In a descriptive-analytical study, the cryptosporidium contamination of 200 lettuce samples from four different regions was investigated during spring and summer, 2006. All samples were processed and examined using modified Ziel-Neilsen staining and also by a quantitative method for counting oocystes per sample. From a total of 200 samples, forty seven samples [23.5%] were positive. No significant difference was seen between contamination rate of lettuce and seasons, except for samples from Jahrom, where showed higher contamination rate in spring than summer. In addition, no significant difference was observed among oocytes count in different samples, except for lettuce from Ahwaz in summer with higher parasite intensity. Regarding to the high contamination of lettuce with Cryptosporidium, as well as to sanitary washing of vegetables before consumption, taking special procedures appear to be helpful for reducing the contamination rate at the farm level

[Antioxidant, color and antibacterial properties of edible chitosan film incorporated with Zataria multiflora boiss essential oil against Listeria monocytogenes]

The film containing antimicrobial agents are a type of active packaging which is mainly designed to control microbial and chemical spoilage of food. The aim of this study was to evaluate the antimicrobial, antioxidant and color properties of chitosan film incorporated with essential oil of Zataria multiflora Boiss [ZEO]. In this experimental study which was conducted at Urmia University of Medical Sciences between 2009-2010, the chemical composition of ZEO was analyzed using GC-MS. Chitosan films containing 0, 0.5, 1 and 2% ZEO, were obtained by casting method and subsequently, total phenol [TP], antioxidant, color [accordance with hunter system [L*[luminosity], * [redness, and b* [yelloweness]] and antimicrobial characteristics of films on Listeria monocytogenes were studied. The collected data was analyzed by the SPSS software. The order of TP for all films in the experiment was 2% ZEO>1% ZEO%0.5% ZEO> unsupplemented chitosan film, respectively. It was also conducted that the antioxidant activity of chitosan films was increased by adding various concentrations of ZEO. These increases were significant for film containing 1% [33.98%] and 2% [37.77%] ZEO [p<0.05]. Regarding the color luminosity [L*] of the chitosan film, results indicated no significant changes by incorporating ZEO, whereas the incorporation of ZEO into films had a significant effect on film yellowness, evidenced by lower b* values. Finally, it was shown that the presence of ZEO in chitosan films significantly modified the anti-listerial activity of chitosan, [p<0.05]. The results indicated that an active film from chitosan could be achieved by incorporating ZEO. Addition of ZEO improves functional and antibacterial characteristics of chitosan film

[Extraction and molecular determination of major outer membrane proteins of Brucella abortus S99]

Background: brucellosis is one of the five common bacterial zoonosis caused by a gram negative, non-spore forming, and facultative intracellular bacterial organism belonging to the genus Brucella. Although brucellosis is considered as a health problem for both men and domestic animals in many countries, any licensed human vaccine has not been designed and produced for it yet. To overcome the problem, currently, antigenic determinants of Brucella cell wall e.g. outer membrane proteins [OMPs] and lipopolysaccharide [LPS] are considered as potential candidates to develop subunit vaccines

Materials and Methods: brucella abortus S99 used in the present study is obtained from the standard bacterial collection of Institute Pasteur of Iran. OMPs were extracted by deoxy cholate extraction technique and further purification performed by sequential centrifugation and ultracentrifugation. Protein concentration was determined using the Nano drop ND-10000 spectrophotometer. SDS-polyacrylamide gel electrophoresis [SDS- PAGE] was performed to determine the electrophoretic pattern and the molecular weight of the extracted OMP samples

Results: OMPs concentration of B.abortus S99 has been measured and reported as 6.27 mg/ml. SDS-PAGE analysis indicated one protein band in the range of 36-38 kDa which would be classified as the porins of B.abortus S99

Conclusion: extraction of B.abortus S99 OMPs with the applied method in the present study produced a satisfactory yield of OMPs. These proteins belonging to the second group of OMPs, called porins

[Effect of local hypothermia in prevention or reduction of chemotherapy induced mucositis signs]

Oral mucositis frequently occurs in patients undergoing cancer chemotherapy. It is hypothesized that Oral Cooling with ice chips or cubes cause local vasoconstriction thus cause less exposure to agents and then mucositis development. In this study, this theory was examined on 14 patients in 3 consecutive cycles in which stomatitis developed in the 1 st cycle of treatment. The purpose of the present study was to evaluate the Ice-Therapy [mouth-cooling] in prevention or decreasing symptoms of chemotherapeutic-related stomatitis. Date was obtained on a total of 100 out-patients initiating chemotherapy regimens. The patients reported different rates of stomatitis received ice cubes in their 2nd cycle of treatment during the drug infusion and a few minutes after it. In the next cycle, the same patients were evaluated without mouth cooling. The severity of mucositis were measured based on the patient's judgment and scaled on WHO grading system in the 7th and 10th days. Statistically, comparison of severity rates of mucositis between 3 consecutive cycles were performed by mean, p value, GAMMA coefficient and Friedman test. Statistical approach of data between 3 cycles determined that severity rates of mucositis have been decreased significantly between 1st and 2nd cycles[p<0.01, gamma coefficient: 65%] But this relationship has not been obtained in comparison between 2nd and 3rd cycles so it has been speculated that Oral Cooling has no useful effect on the prevention of chemotherapy-induced mucositis. Oral Cooling has no evidence of benefit in improvement or decreasing of the chemotherapy induced lesions

[Effects of Zataria multiflora boiss. essential oil and nisin, alone and in combination against listeria monocytogen in BHI broth]

In food industry, quality assurance and prolongation of shelf-life is achieved through control of pathogenic and spoilage microorganisms in foods. Regards to much proved adverse effects of synthetic food additives and general concern on the subject, the replacement of these additives with natural based ones such as plant essential oils and natural antibiotics has been raised and researches first at in virto models and then in food systems is necessary. The aim of this study was to determine the antimicrobial activity, minimum inhibitory concentration [MIC] and minimum bactericidal concentration [MBC] of Zataria multiflora Boiss. Essential oil and nisin alone and in combination against Listeria monocytogen in brain heart infusion [BHI] broth. The specifications of combination of essential oil and nisin were determined. In this study 600 micro g/ml of Z. multiflora essential oil and 2.5 micro g/ml nisin in pH value of 5 at 15 [degree sign] C were used. In this study Zataria multiflora essential oil had antimicrobial effects agains Listeria monocytogen [MBC: 19, MIC: 9.5 micro g/ml]. Combination of nisin and the essential oil had also antimicrobial effects against Listeria monocytogen [MIC: 1.2, MBC:2.4 micro g/ml]. Zataria multiflora essential oil and nisin were effective against Listeria monocytogen alone. This effect was obviously increased in combination with each other and the results were noticeable

[Frequency of the relative presence of hepatitis c virus genome in oral lichen planus]

Oral lichen planus [OLP] is an immunologic mucocutanous disorder. Many factors such as stress, diabetics, HCV, Trauma and hypersensitivity have been introduced as its predisposing factors. Recently, much attention has been paid to the relationship between HCV and OLP. According to different specifications of the virus in different races and geographic conditions, the purpose of this study was the assessment of the presence of HCV in oral lichen planus lesions. We prepared 43 paraffin blocks [29 from OLP and 14 from normal oral mucosa]. The OLP blocks were selected from the archive of Pathology department, dental faculty, Esfahan University of Medical Science. After preparing H and E slides from the paraffin blocks, diagnosis of the lesions was confirmed by a pathologist. Then, all the samples were examined by PCR for HCV genome. The data were analyzed using SPSS software and Fisher's Exact rest with P value of 0.05. Among 43 samples examined, 3 were positive and 26 negative in the OLP group and all the 14 samples belonging to the normal mucosa were negative. According to this study, there was no significant correlation between the presence of Hepatitis C virus genome and OLP lesions [p>0.05]. So, researches on other viruses that are effective in oral diseases with more cases and also doing PCR on the blood and serum of OLP patients are recommended

[Study on antibacterial effects of artemia urmiana cyst shell chitosan on listeria mo-nocytogenes, staphylococcus aureus, salmonellatyphimurium and escherichia coli]

Chitosan is a natural antimicrobial which is derived from non-toxic animal resources. This study investigated and compared the antimicrobial characteristics of chitosan which was extracted from shell of Artemia cyst in the lake of Urmia with the same commercial chitosan feature to that of crab shell from A.P.T firm in Vietnam. The experiment was carried by means of two fulded method to find the minimum inhibitory concentration [MIC] of commercial chitosan and Artemia chitosans and [4,2,1,0/5,0/25,0/125,0/062 mg/ml] [6/4,3/2,1/6,0/8,0/4,0/2,0/1 mg/ml] on Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Listeria monocytogenes. MIC of Artemia chitosan for those bacteria and MIC of commercial chitosan were determined 500 ppm and 800 ppm. In the next phase, each of those four bacterias was separately exposed to MIC Artemia chitosan and during 8 h of incubation at 37°C were artificially cultivated every 2 h and colonies appearing on the plates after 24 h of incubation were counted and the death time graph of the bacterias was drown to study their destruction process in the presence of MIC of Artemia chitosan. Experimental achievements showed that in this period of destruction speed in Staphylococcus aureus was more than others and the destruction speed of Salmonella typhimurium was the least. Also studying the achieved pictures by electronic microscope from the from two bacterias, gram-positive Staphylococcus aureus and gramnegative Escherichia coli which were exposed to MIC of Artemia chitosan [500 ppm] depicted that the speed of influence by Artemia chitosanon gram-positive bacteria is much more than gram-negative bacteria. Results of this study depict great abilities of Artemia chitosan in destroying studied bacteria in comparis on with those of commercial one

Assessing the compatibility rates of governmental dentistry centers of Tehran with desirable infection control criteria and the factors involved, 2004

Dentistry systems should meet criteria of infection controls. Higher compatibility will result in more desirable system situation. To determine the conformation rates of governmental dentistry centers located in south and southwest of Tehran with desirable criteria for infection control and the affecting factors. This was a cross-sectional descriptive study performed on 74 governmental dentistry centers in south and south west of Tehran province in 2004. Achecklist including 10 axes was used to investigate 141 identities for their conformity to meet infectious control criteria via direct observation. Following the analysis of data by SPSS-V11.5 and the application of t-test and Chi square test, the situation of centers were placed into three rankings as follows: Under expected [75%]. Their desirable degree was tested by 10 presumptive effective factors. Among 74 investigated centers in the study, 40 centers were located in the south of Tehran, 24 in Shahr-e-Rey, and 10 in Islamshahr with a mean conformation to desirable criteria of 56.3, 52.5, and 60.1%, respectively. Collectively, 12 centers [16.2%] were placed in under expected, 60 centers [81.1%] in medium, and 2 centers [2.7%] in desirable ranking. Availability of dentists with specialty, being a member of academic staff, and the presence of dental clinic in university hospitals were found to produce a significant impact towards the desirability, statistically [p<0.05]. According to our findings, monitoring and solving the problems of centers with under expectable limit to meet the desirable criteria is suggested

[Assessment of hospital sterilizer equipments performance and related effective factors]

For controlling the nosocomial infections in the hospitals, use of sterilizer devices such as: steam autoclave, chemiclave, Gas plasma, Oven and Vaporized Hydrogen Peroxide are approved. According to standardized directions, these equipments needs to be tested physically, chemically and biologically continuously. The most trusted way for sterilization monitoring is the biologic one. The main purpose of this study is to assess the performances of the sterilizer devices, that are presented in affiliated hospitals to Tehran University of medical sciences with biologic monitoring way. This is a cross - sectional study conducted in all 135 devices that are presented in CSR units of 14 hospitals and related responsible staff. In this study, sterilization process was assessed by using of spores, microbial vials and culturing of the samples and also, the Knowledge of CSR personnel was measured by a valid and reliable questionnaire. We have used, T-Test for data analysis in this study. 14 out Of 135 devices [10.4%] were not in good function, there was a significant relationship between age of personnel and their knowledge. There were significant relations between the sex [0.001], educational grade [0.02], years of experiences, and the knowledge of the staff [P=0.001] and also CSR unit area in this study. This study suggests that hospitals must have CSR units with sufficient area and educated personals in related fields. They must also regularly educate the staff, especially males that are responsible in CSR units

[Comparison of one versus two appointments endodontic therapy on healing of periapical lesions in dogs, teeth]

Apical periodontitis is caused by bacteria within root canals. Logically, the treatment of apical periodontitis should be directed to the removal of the cause, i.e bacterial eradication. The best procedure for disinfection is canal debridement and irrigation during the first appointment, followed by the application of calcium hydroxide dressing for one week. MTAD, a Mixture of Tetracycline isomer, Acid and Detergent is a new antibacterial solution which has been claimed to be useful in one visit treatment. The purpose of this study was to compare healing of periapical lesions after one visit treatment using MTAD with two appointments endodontic therapy by calcium hydroxide in dogs teeth. Forty incisor and first premolars of four dogs were left open for four months until periapical lesions developed. Twenty root canals were treated endodontically using MTAD in one visit, and the other 20 canals were dressed with calcium hydroxide for 1 week, and endodontic treatments were then completed. Six months after treatment the dogs were killed by vital perfusion. After fixation, the teeth were histologically examined for the healing of periapical lesions. Kruskal-wallis and Mann-Whitney tests were used for statistical analysis. The percentage of healing, advanced organization, organization, and acute inflammation for MTAD group were 3 1.6%, 26.3%, 36.8%, and 5.3%, while for calcium hydroxide group they were 16.7%, 16.7, 55.6%, and 11.1% respectively. The difference between the two groups was not statistically significant [p>0.05], but healing of lesions progressed better in MTAD group. One-visit treatment by use of MTAD for pulpless teeth with periapical lesion is an acceptable alternative therapy to two-visit treatment using calcium hydroxide