Genotyping of Acanthamoeba Isolated from Hospital Environments and Thermal Water of Recreational Baths in Markazi Province, Iran.

Background: Due to the opportunism character of Acanthamoeba, the presence of this parasite in the thermal water of recreational baths and hospital environments can be a risk to the health of staff, patients and others. The aim of this study was to investigate the distribution of potentially pathogenic Acanthamoeba genotypes isolated from the hospital environment and the thermal water of recreational baths in Markazi Province, central Iran. Methods: Overall, 180 samples including thermal water from recreational baths in Mahallat City and dust, soil and water from different hospitals of Arak, Farahan and Komijan cities, central Iran were collected. The presence of Acanthamoeba was investigated using microscopic examination and molecular methods. The PCR and sequencing was performed based on a specific 18S fragment of ribosomal DNA. Results: Based on the microscopic survey, totally 134 positive samples were detected including 35% in thermal water samples and 44.7% in hospital samples. In molecular analysis, 53.5% of the samples were identified as Acanthamoeba and 46.7% as Protacanthamoeba bohemica. The genotypes were detected as T4 (33.3%), T2 (10%), T11 (6.7%), and T5 (3.3%). Conclusion: The T4 was the most common genotype found in hospitals sampling sites while the T2 genotype and P. bohemica were detected in thermal water sampling sites.

Evaluation of national dental curriculum in Iran using senior dental students' feedback.

BACKGROUND: Dental curriculums require regular revision to stay up to date in scientifical and societal fields. Senior dental students are among the main stakeholders of such curriculums. The present study investigated the opinions of Iranian senior dental students regarding the adequacy of their dentistry program and the national dental curriculum in training a competent dentist, the program's content, and its structure. METHODS: A previously designed and validated questionnaire on the opinion of senior dental students regarding curriculum adequacy was sent to a representative in each of the country's dental schools. Before the COVID pandemic terminated data collection, a total of 16 schools (438 students) managed to respond (37%). The questionnaire asked the students to assess the adequacy of the training received in curriculum's theoretical and practical competencies with the help of a five-point Likert scale that ranged from "Completely inadequate" to "Completely adequate". It also questioned them on its teaching methods and intensity. SPSS software version 24 and Chi-square test served for statistical analysis. RESULTS: In total, the study has 438 participants, 245 female and 193 male. Significant sex differences were spotted in the responses concerning both theoretical and practical training. Regarding general training adequacy, 50 (22.6%) female students and 50 male ones (30.7%), P = 0.08 agreed that the program was acceptable. The numbers for students of old (more than 15 years of activity) and new schools were 47 (21.7%) and 53 (31.7%), respectively (P = 0.03). Nearly one-third deemed the teaching methods appropriate. Regarding the duration of curriculum phases, 33 students (8.3%) believed that basic science required extension, while 108 (28.6%) and 266 (69.1%) reported such need for pre-clinical and clinical phases. The school's years of activity emerged as significant, as 38.1% of students from new schools versus 21.7% of those from old ones deemed the extension of pre-clinical phase necessary (P < 0.001). CONCLUSION: A significant number of Iranian senior dental students found the undergraduate dental curriculum inadequate regarding competencies, content, and teaching. Further investigations will determine whether it's the curriculum or its implementation that warrants revision.

The Application of a Recombinant Antimicrobial Peptide of Thrombocidin-1 Expressed in Pichia pastoris as a Novel Approach Against Some Oral Pathogenic Bacteria: An In Vitro Study.

OBJECTIVE: Oral infections and dental caries are considered serious health problems. Therefore, searching for new agents with antimicrobial properties seems to be crucial. This study aimed to evaluate the antimicrobial activity of the recombinant Thrombocidin-1 [TC-1] peptide on some oral pathogens. Also, the cytotoxicity of this peptide on human gingival fibroblast cells was investigated. METHODS: In this study, Pichia pastoris was used for the expression of recombinant TC-1. The microbroth dilution method was used to determine the minimum inhibitory concentration [MIC] and minimum bacterial concentration [MBC]. It tested against four main oral pathogens; Streptococcus mutans, Streptococcus salivarius, Streptococcus oralis, and Enterococcus faecalis. Moreover, the cytotoxicity analysis was done on gingival fibroblast cells by the MTT method. The data were analyzed using a two-way analysis of variance [ANOVA] and Tukey's HSD tests. RESULTS: The most bactericidal effect of TC-1 was against S. salivarius, the highest bacteriostatic effect was against S. salivarius, and S. oralis had the lowest MIC value of 1.512 µg/ml. The Thrombocidin- 1 peptide showed lower antibacterial properties against E. faecalis compared with CHX, unlike the stronger antimicrobial effect on examined streptococci. According to cytotoxicity examination, no concentration of TC-1 presented over 50% growth inhibition [IC50] of the fibroblasts cells. CONCLUSION: Based on antimicrobial tests and cytotoxicity results, the Thrombocidin-1 peptide may be useful as a safe antibacterial agent against some oral pathogens in dental materials.

The validity of laser fluorescence (LF) and near-infrared reflection (NIRR) in detecting early proximal cavities.

OBJECTIVES: Diagnosing cavitated proximal lesions is important for therapeutic decisions. This clinical study aimed to determine the validity of laser fluorescence (LF) and near-infrared reflection (NIRR) techniques for detecting early proximal cavities. MATERIALS AND METHODS: The study included 43 proximal surfaces in 15 females who had limited radiolucent lesions in their bitewing radiographs. The approximal areas of interest were assessed by DIAGNOdent Pen (LF) and the Proxi interchangeable head of VistaCam iX intraoral camera (NIRR). Finally, orthodontic separators were placed in the contact points to provide enough space between the teeth. The sensitivity, specificity, and accuracy of diagnosing cavitated proximal surfaces were calculated for LF and NIRR against direct visual and tactile examination as the reference standard. RESULTS: On the basis of the reference standard, 34 surfaces (79.1%) were not cavitated, whereas 9 surfaces (20.9%) were cavitated and in need of restoration. The sensitivity, specificity, and accuracy of LF were 44.4%, 61.8%, and 58%, and those of NIRR were 88.9%, 14.7%, and 30%, respectively. CONCLUSIONS: The VistaCam iX Proxi was more sensitive and DIAGNOdent Pen was more specific in detection of proximal cavities. However, none of the techniques was accurate enough to be recommended as a sole approach for proximal caries detection. CLINICAL RELEVANCE: LF showed an overall superior diagnostic performance to NIRR for diagnosing proximal cavitation in permanent posterior teeth. Within the limitations of this study, neither VistaCam iX Proxi nor DIAGNOdent Pen could be considered a suitable device for diagnosing proximal cavities.

The effect of sodium hexametaphosphate on sensitivity and whitening effectiveness of an at-home bleaching gel: a randomized, triple-blinded clinical trial.

OBJECTIVE: Bleaching sensitivity (BS) is the most common adverse effect of tooth bleaching treatments. This study evaluated the effect of adding 1% sodium hexametaphosphate (SHMP) on BS and the whitening effectiveness of a bleaching gel. METHOD AND MATERIALS: Two maxillary quadrants from 26 patients were randomly assigned to the experimental and control groups in a split-mouth design. In the control group the at-home bleaching gel containing 3% hydrogen peroxide, and in the experimental quadrant the same gel with 1% SHMP, were applied in individual trays for 6 hours per night for 2 weeks. The patients' sensitivity to cold and touch as well as spontaneous sensitivity were recorded based on a visual analog scale (VAS). Changes in shade guide units (ΔSGU) and ΔE were measured using a spectrophotometer. Data were analyzed using the Kolmogorov-Smirnov, Mann-Whitney U, Wilcoxon signed-rank test, and independent sample t test. RESULTS: Twenty-four patients completed the study. After 2 weeks, the sensitivity to cold and touch was significantly lower in the intervention group compared to the control (P = .015 and P = .039, respectively). The spontaneous sensitivity revealed no significant alteration between these two groups and during the bleaching period in each group (P > .050). Regarding both color measurements, the bleaching effectiveness in both groups was comparable, with no noticeable difference (P > .050). CONCLUSION: The application of 1% SHMP was able to reduce the BS with no detrimental effect on the at-home bleaching effectiveness. (Quintessence Int 2021;52:596-605; doi: 10.3290/j.qi.b1098303).

A New Approach Against Some Oral Pathogenic Bacteria Using a Chimeric Antimicrobial Peptide Derived from the Camel Milk; Lactoferrampin - Lactoferricin Chimer.

OBJECTIVES: The present study was conducted to evaluate the antimicrobial effects of the recombinant chimer present in the lactoferrampin-lactoferricin [LFA-LFC] derived from the camel milk on some oral bacteria responsible for dental caries and endodontic failures. METHODS AND MATERIAL: The antimicrobial activity was assessed on the Streptococcus mutans [ATCC 35668], Streptococcus salivarius [ATCC 9222], Streptococcus oralis [ATCC 35037], and Enterococcus faecalis [ATCC 29212], using the microbroth dilution method. The cytotoxicity analysis was done through the MTT method on the human gingival fibroblasts. The data were reported using the descriptive methods and were analyzed by the one-way analysis of variance (ANOVA) and Tukey HSD test. RESULTS: Results showed that the chimeric peptide had the highest bacteriostatic effect on S. salivarius with the lowest minimum inhibitory concentration value of 1.22 µg/Ml. Also, LFA-LFC chimer was more effective against S. mutans and S. salivarius compared to using 0.2% chlorhexidine mouthwash. The minimum bactericidal concentration analysis showed the most bactericidal effect against S. mutans [1.256 µg/mL]. In spite of the greater antibacterial effect on the evaluated streptococci, this peptide showed lower bacteriostatic and bactericidal properties against E. faecalis compared to the chlorhexidine. Based on cytotoxicity assay, over 50% of the cells were viable in all the evaluation times, demonstrating the biocompatibility of the peptide. CONCLUSION: The LFA-LFC chimer revealed comparable or even more effective antibacterial properties compared to the chlorhexidine mouthwash against the caries-inducing bacteria with no toxicity on the human gingival fibroblast cells. So, this peptide can be used as a safe alternative to chlorhexidine and other chemicals in dental applications for the prevention and management of dental caries.

The effective and safe method for preventing and treating bacteria-induced dental diseases by herbal plants and a recombinant peptide.

BACKGROUND: This study was conducted aimed at evaluating the antibacterial property of the recombinant peptide of bacteriocin entrocin P (EnP), the essential oil of Cuminum cyminum, and the extract of Ferulago angulata on some oral pathogens. Besides, the cytotoxicity of EnP was evaluated. MATERIAL AND METHODS: The antimicrobial property was tested on streptococcus mutans (ATCC 35668), streptococcus salivarius (ATCC 9222), streptococcus oralis (ATCC 35037), and Enterococcus faecalis (ATCC 29212), using the microbroth dilution method. The 0.2% Chlorhexidin (CHX) mouthwash was used as the control group. Besides, the cytotoxicity analysis was done on gingival fibroblasts by the MTT colorimetric method. The data were reported using descriptive methods, and analyzed by one-way ANOVA, and Tukey's HSD test. RESULTS: The strongest bacteriostatic and bactericidal effects of C. cyminum and F. angulata were observed for S.mutans and S. oralis, respectively (with the MIC and MBC value being 62.5 µg/mL). The antibacterial properties of EnP were comparable to those of CHX, being several times stronger than medicinal plants (1-14 µg/mL). Based on the cytotoxicity evaluation, there was no statistically significant difference observed between the cytotoxicity of the control group and that of Enp for three evaluations, except after 72 hours when the cell viability at the concentration of 3.75 µg/ml was significantly lower than that of the control group (P=0.05). However, no concentration of EnP was observed to be over 50% of the growth inhibition (IC50) of the fibroblasts for the three evaluations. CONCLUSIONS: EnP could be utilized in dental materials as a natural and safe antimicrobial agent against oral streptococci and E. faecalis, being as effective as CHX mouthwash. Key words:Antimicrobial peptide, Bacteriocin Entrocin P, Chlorhexidine, Cuminum cyminum, Enterococcus faecalis, Ferulago angulata.

The efficacy and complications of several bleaching techniques in patients after fixed orthodontic therapy. A randomized clinical trial.

This study aimed to evaluate the efficacy and complications of several bleaching methods in patients with discolored teeth after orthodontic treatment. This randomized clinical trial involved 60 volunteers (31 women, 29 men) aged 14 to 30 years, who finished fixed orthodontic therapy at least three months before the study commencement and complained of discoloration on upper front teeth. The subjects were divided into four groups by treatment. The patients in group 1 received home bleaching, whereas those in groups 2 to 4 underwent in-office bleaching using a diode laser, a plasma arc and no light source, respectively. Tooth color was measured at baseline, one hour after the end of the bleaching procedure, and one week later, and the color alteration between different stages was compared among the groups. The severity of tooth sensitivity and the occurrence of other post-treatment complications were recorded. The color change between baseline and one week after treatment was greatest in the home-bleaching and the laser-assisted bleaching groups, and lowest in the plasma-arc bleaching group, although the difference between the groups was not significant (p > 0.05). Tooth sensitivity over 24 hours after bleaching was lowest in subjects who had undergone laser-assisted bleaching and highest in those who had received in-office bleaching without light (p < 0.05). All methods were effective in managing tooth discoloration after orthodontic treatment. Home bleaching produced favorable color alteration. Amongst the in-office approaches, laser-assisted bleaching should be considered as the best option, as it produced effective results with lowest tooth sensitivity and over a shorter period of time.

Molecular Detection of Campylobacter Species: Comparision of 16SrRNA with slyD, cadF, rpoA, and dnaJ Sequencing.

BACKGROUND: Campylobacter spp. are the main cause of human gastroenteritis. The 16SrRNA sequencing is one of fast molecualr method to detect this fastidious. In this study, we compared the sequencing of 16srRNA genewith four housekeeping genestodetect Campylobacter spp. in patients with diarrhea and healthy people. METHODS: 60 samples of Campylobacter DNA extracted from stool samples of 30 patients with diarrhea and 30 healthy people were used. In order to detect Campylobacter, we designed primers for proliferation of 16SrRNA, cadF, dnaJ, slyD , and rpoA genes using Primer 3, Mega 4.0 and Blast software. Then the PCR products were sequenced using ABI system. RESULTS: The sequencing showed concordance of PCR-products with deposited sequences in the Gene Bank. Among diarrhea patients, 53.3% of samples were significantly (p< 0.05) positive for slyD and cadF genes and 50% of samples were positive using 16SrRNA, rpoA, and dnaJ genes by PCR assay. The average of sensitivity and specificity were found 53.33% and 83.33%, respectively. CONCLUSION: Due to various copies of repeated sequences of 16SrRNA gene, analyzing its amplicons on electrophoresis may be more difficult than the slyD and cadF genes. According to our results, among the 5 studied genes; the highest detection rate was related to slyD and cadF genes. Although, dnaJ and rpoA genes,instead of 16SrRNA gene, can be considered as appropriate genes for molecular detection of Campylobacter bacteria.

Effect of Adding Nano Size Silica on Setting Time and Porosity of Mineral Trioxide Aggregate.

Introduction: The aim of this study was to evaluate the effect of addition of nano-silica (SiO2) to mineral trioxide aggregate (MTA) on its setting time and porosity. Methods and Materials: The concentration 8% of nano-silica were prepared and added to the MTA powder. After mixing with water the setting time and porosity were evaluated and compared with pure MTA. Statistical analysis was performed using the t-test. The level of significance was set at 0.001. Results: The mean setting time of MTA+8% nano-silica (9.8±0.78) was significantly lower than MTA (23.3±2.16) ( P<0.001). Also the mean porosity by imbibition method in MTA+8% nano-silica (23.49±0.48) was significantly higher than MTA (15.69±2.10) (P<0.001). There was no significant difference in mean porosity by scanning electron microscope (SEM) method in MTA+8% nano-silica (31.26±10.73) and MTA (32.74±5.26) (P>0.001). Conclusion: This in vitro study showed us an addition of 8% of nano-silica to MTA reduced the setting time. Although evaluation by imbibition test showed increasing of porosity in nano-silica MTA compared with pure MTA.

Effect of Non-Vital Bleaching on the Durability of Resin⁻Dentin Bond with an Ethanol-Based Etch-And-Rinse Adhesive.

To evaluate the bleaching procedure and application of sodium ascorbate on dentin bond durability, the enamel surface of intact human third molars (n = 18) were removed, and the teeth were randomly divided into two groups for immediate and six-month bond strength evaluation. The specimens were further assigned into three subgroups according to treatment procedure, as follows: subgroup A, no bleaching (positive control) was performed prior to the etch-and-rinse bonding with single bond and subsequent build-up with Z250 composite; subgroup B, the samples were bleached with 20% carbamide peroxide 6 h/day for five consecutive days prior to bonding; and subgroup C, bleaching was performed as in subgroup B, after which 10% sodium ascorbate was applied on dentin surface for 10 min before the bonding procedures. A microtensile bond strength test was performed and the failure modes were evaluated under a stereomicroscope. The data were analyzed using two-way analysis of variance (ANOVA) and Tukey's post-hoc tests with a level of significance of 0.05. Bleaching significantly decreased the immediate and six-month bond strength. The application of sodium ascorbate had no significant effect on the immediate and six-month bond strength of bleached specimens. We conclude that the bleaching procedure may decrease the durability of the resin-dentin bond of the tested etch-and-rinse adhesive.

Comparison of Tooth Discoloration Induced by Calcium-Enriched Mixture and Mineral Trioxide Aggregate.

INTRODUCTION: The aim of this in vitro study was to evaluate the tooth discoloration induced by calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA). METHODS AND MATERIALS: Forty five endodontically treated human maxillary central incisors were selected and divided into three groups (n=15) after removing the coronal 3 mm of the obturating materials. In the MTA group, white MTA plug was placed in pulp chamber and coronal zone of the root canal. In CEM cement group, CEM plug was placed in the tooth in the same manner. In both groups, a wet cotton pellet was placed in the access cavity and the teeth were temporarily sealed. After 24 h the teeth were restored with resin composite. In the negative control group the teeth were also restored with resin composite. The color change in the cervical third of teeth was measured with a colorimeter and was repeated 3 times for each specimen. The teeth were kept in artificial saliva for 6 months. After this period, the color change was measured again. Data were collected by Commission International de I'Eclairage's L*a*b color values, and corresponding Δ E values were calculated. The results were analyzed using the one-way ANOVA and post-hoc Tukey's test with the significance level defined as 0.05. RESULTS: There was no significant differences between CEM group and control group in mean discoloration. The mean tooth discoloration in MTA group was significantly greater than CEM and control groups (P<0.05). CONCLUSION: According to the result of the present study CEM cement did not induce tooth discoloration after six months. Therefore it can be used in vital pulp therapy of esthetically sensitive teeth.

The curli biogenesis genes expression level is unassociated with Enterobacter cloacae hsp60 clusters and PFGE genotypes.

The objective of this study was to determine the correlation between Enterobacter cloacae complex subspecies and clusters involved in UTI infections and specific pulsotypes, and to assess the contribution of major curli biogenesis genes (csgD, csgA) expression level to pathogenesis of clusters and genotypes. Based on the PFGE analysis, 37 different profiles were observed among which 8 profiles were common types. Real time PCR of csgD and csgA genes of 50 E. cloacae complex in relation to PFGE and hsp60 genotypes showed that all the genetic clusters are not equally involved in pathogenesis of urinary tract infections. It was elucidated in this study that isolates with common PFGE genotypes belonged to identical hsp60 clusters, and the foremost clusters (VI, III, and V) mainly comprised within PFGE common types. In our study, no significant correlation was detected between the specific hsp60 clusters or PFGE genotypes and the expression level of csgD and csgA genes (P-value > 0.05). This is the first study describing that unequivalent contribution of E. cloacae genotypes and clusters in pathogenesis of UTI, is not owing to varied curli biogenesis expression potential. The PFGE genotyping showed more discriminatory power than hsp60 genotyping for epidemiological studies and source tracking purpose.

Low Prevalence of Aeromonas hydrophilain Infectious Diarrhea Samples of Pediatric Patients in Arak, Iran.

BACKGROUND: Aeromonashydrophila (A. hydrophila) is an aquatic bacterium that can cause a spectrum of infectious diseases, including both gastrointestinal and extraintestinal infections. Due to the high rate of diarrheal infections in pediatric patients in central Iran, this study was designed to determine the frequency of A. hydrophila in diarrhea samples from children in this region. METHODS: In this descriptive cross-sectional study, diarrheal stool specimens were collected from 200 children admitted between February and October of 2015 to educational and medical centers affiliated with the Arak University of Medical Sciences. The samples were analyzed both phenotypically by culture and genotypically by the polymerase chain reaction (PCR). RESULTS: A. hydrophila was isolated from two of the 200 samples tested (1%). The presence of bacterial genetic markers further confirmed the diagnosis. CONCLUSION: Based on this study, A. hydrophilais not highly prevalent in children with diarrhea in Arak; however clinical diagnostic laboratory personnel should be aware of the possible presence of A.hydrophila in children with diarrhea as it can cause dangerous health problems in both them and young adolescents.

Particular Distribution of Enterobacter cloacae Strains Isolated from Urinary Tract Infection within Clonal Complexes.

BACKGROUND: Based on biochemical properties, Enterobacter cloacae represents a large complex of at least 13 variant species, subspecies, and genotypes that progressively identified as the most species causing hospital-acquired infections. The aim of this study was to determine the relevance between phylogenetically related strains within the E. cloacae complex and the frequency of urinary tract infection caused by them. METHODS: A 268-bp fragment was obtained from hsp60 gene for 50 clinical E. cloacae isolates from urine cultures of inpatients that admitted to six hospitals in Tehran, Iran during December 2012 to November 2013. The 107 nucleotide sequences were analyzed and the evolutionary distances of sequences were computed and neighbor-joining tree was calculated. RESULTS: It showed that all of the genetic clusters have not an equal involvement in pathogenesis of urinary tract infections. Three superior clusters were found, together representing more than two third (80%) of the isolates (cluster VI with 25 members; clusters III and VIII with 9 and 6 members, respectively) and some genetic clusters were absent (IV, X, XII, and xiii), some of which are supposed to be associated with plants and no human infection has been reported. CONCLUSIONS: This study, for the first time, reports the unequal contribution of E. cloacae complex subspecies and clusters in urinary tract infections in Iran and together with studies from other countries suggest that the subspecies of E.hormaechei subsp. Oharae is the most prevalent E. cloacae complex subspecies regardless of country under study.

Microhardness of demineralized enamel following home bleaching and laser-assisted in office bleaching.

BACKGROUND: There is little data regarding the effect of tooth whitening on microhardness of white spot lesions. This study was conducted to investigate the effect of home-bleaching and laser-assisted in-office bleaching on microhardness of demineralized enamel. MATERIAL AND METHODS: Forty bovine incisors were selected and immersed in a demineralizing solution for 12 weeks to induce white spot lesions. Enamel blocks were prepared and randomly assigned to two groups of 20 each. The first group underwent home bleaching with 15% carbamide peroxide which was applied for 8 hours a day over a period of 15 days. In the second group, in-office bleaching was performed by 40% hydrogen peroxide and powered by irradiation from an 810 nm gallium-aluminum-arsenide (GaAlAs) diode laser (CW, 2W). This process was performed for 3 sessions every seven days, in 15 days. The specimens were stored in Fusayama Meyer artificial saliva during the experiment. Surface microhardness was assessed before and after the bleaching therapies in both groups. RESULTS: Microhardness decreased significantly following both home bleaching and laser-assisted in-office bleaching (p<0.05). There were no significant differences in hardness values among the two groups either before (p=0.131) or after (p=0.182) the bleaching procedures. CONCLUSIONS: Tooth whitening through home bleaching or laser-assisted in-office bleaching can result in a significant reduction in microhardness of white spot lesions. Therefore, it is suggested to take protective measures on bleached demineralized enamel. Key words:White spot lesion, bleaching, laser, microhardness, demineralized enamel, home bleaching, in-office bleaching.

Genotyping of vancomycin resistant enterococci in arak hospitals.

BACKGROUND: Enterococcal species have emerged as important pathogens in Iran as well as throughout the world. With the increased use of vancomycin, Vancomycin-Resistant Enterococci (VRE) has become an important nosocomial pathogen. OBJECTIVES: The aim of the present study was to determine the incidence and antimicrobial susceptibility pattern of VRE and also to determine the most important genes that cause resistance to vancomycin in clinical samples in Arak, Iran. MATERIALS AND METHODS: In total, 200 enterococci samples were collected from clinical specimens of Arak hospitals. Enterococcal species were identified using standard biochemical tests. Antibiotic susceptibility was tested by the Clinical and Laboratory Standards Institute (CLSI) disk diffusion. Minimum Inhibitory Concentration (MICs) was determined by broth micro dilution. All of the VRE isolates were examined by PCR to detect the presence of VRE genes. RESULTS: Disk diffusion agar showed that 96 strains (48%) were resistant to gentamicin, 89 (44.5%) to ciprofloxacin, 127 (63.5%) to erythromycin, 142 (71%) to tetracycline, 11 (5.5%) to teicoplanin, 32 (16%) to vancomycin, none to linezolid and 96 (48%) to co-trimoxazole. The MICs of the resistant isolates were as follows; 88 strains had MIC ≥ 32 µg/mL to vancomycin and 59 strains had MIC ≥ 32 µg/mL to teicoplanin. Molecular studies revealed that 59.09% of VRE contained VanA genes and 7.95% of VRE contained the VanB genes. None of the strains had vanC1 and vanC2/3 gene. CONCLUSIONS: According to the results of this study, rates of vancomycin-resistance in enterococci, in Iran like other parts of the world, is increasing. Therefore accurate methods are required for identifying strains that possess resistance genes because many cases of hospital infections are caused by these strains.

Anterior traumatic dental injuries in East Iranian school children: prevalence and risk factors.

INTRODUCTION: The aim of this cross-sectional study was to determine the prevalence and etiology of traumatic dental injuries (TDI) in school children of the Northeast of Iran. The type of involved teeth, the place of injury and treatment quality as well as the relationship between TDI and anatomic predisposing factors such as overjet and lip coverage were evaluated. METHODS AND MATERIALS: A total of 778 school children were clinically examined for signs of trauma to their permanent teeth and the amount of overjet and lip coverage were also recorded. A questionnaire containing demographic data of participants and history of the dental trauma was given to the children's parents. The data were analyzed using the chi-square and Mann-Whitney tests. RESULTS: One hundred and seventy eight (22.9%) children had a history of previous trauma to their permanent teeth. There was a significant difference between boys and girls (P=0.017). A total of 46.1% of children had experienced luxation injuries of permanent teeth, 37% had crown fractures, and 16.9% experienced avulsion of anterior teeth. Maxillary central incisors were the most commonly affected teeth (84%). There was a significant relationship between TDI and overjet (P=0.02) in permanent teeth. On the other hand, there was no statistically significant relationship between TDI and lip coverage. The most common cause of TDI was falling over (42.9%) followed by fighting (34%). The majority of traumas happened at home (46.8%) and school (29.9%). Sixty two (39.7%) children with TDI did not receive any dental or medical care after injury. CONCLUSION: The prevalence of dental trauma in school children in Iran was rather high (22.9%); the most common type of trauma to the permanent teeth was luxation injuries.

The efficacy of laser-assisted in-office bleaching and home bleaching on sound and demineralized enamel.

AIMS: This study investigated the effectiveness of laser-assisted in-office bleaching and home-bleaching in sound and demineralized enamel. MATERIALS AND METHODS: The sample consisted of 120 freshly-extracted bovine incisors. Half of the specimens were stored in a demineralizing solution to induce white spot lesions. Following exposure to a tea solution for 7.5 days, the specimens were randomly assigned to 4 groups of 30 according to the type of enamel and the bleaching procedure employed. Groups 1 and 2 consisted of demineralized teeth subjected to in-office bleaching and home bleaching, whereas in groups 3 and 4, sound teeth were subjected to in-office and home bleaching, respectively. A diode laser (810 nm, 2 W, continuous wave, four times for 15 seconds each) was employed for assisting the in-office process. The color of the specimens was measured before (T1) and after (T2) staining and during (T3) and after (T4) the bleaching procedures using a spectrophotometer. The color change (ΔE) between different treatments stages was compared among the groups. RESULTS: There were significant differences in the color change between T2 and T3 (ΔE T2-T3) and T2 and T4 (ΔE T2-T4) stages among the study groups (p<0.05). Pairwise comparison by Duncan test revealed that both ΔET2-T3 and ΔET2-T4 were significantly greater in demineralized teeth submitted to laser-assisted in-office bleaching (group 1) as compared to the other groups (P< 0.05). CONCLUSION: Laser-assisted in-office bleaching could provide faster and greater whitening effect than home bleaching on stained demineralized enamel, but both procedures produced comparable results on sound teeth.

Cone-beam computed tomography evaluation of maxillary first and second molars in Iranian population: a morphological study.

INTRODUCTION: The aim of this in vitro study was to identify the root and canal morphology of maxillary first and second molars in Iranian population by taking and analyzing cone-beam computed tomography (CBCT) scans. METHODS AND MATERIALS: Extracted maxillary first (n=125) and second (n=125) molars were collected from native Iranians and scanned by using a CBCT scanner. The number of roots and configuration of root canal system were classified according to Vertucci's classification. RESULTS: Two (1.6%) maxillary first and two (1.6%) maxillary second molars had four roots. Prevalence of root fusion was 2.4% and 8.8% in maxillary first and second molars, respectively. The most common canal morphology in the mesiobuccal roots of three-rooted first and second molars was type I (46.4% and 80.8%, respectively), followed by type VI (17.6%) in first molars. The predominant morphology of distobuccal and palatal roots in first and second molars was type I. Additional canal types were also identified. CONCLUSION: Profound knowledge of anatomic variations is necessary prior to cleaning and obturation of the root canal system. The most common discovered root morphology was three separate roots in both tooth types. The greatest variation in canal anatomy was discovered in the MB canals of both the first and second molars.