The effects of botulinum toxin A injection on the lateral pterygoid muscle in patients with a painful temporomandibular joint click: a randomized clinical trial study.

BACKGROUND: Temporomandibular disorder (TMD) is the main cause of non-dental pain in orofacial area. The most common symptoms of TMD are joint pain, joint sound and limitation of jaw function. Botulinum toxin (BTX) injection is considered a potential treatment for TMD due to its pain-relieving properties and its ability to reduce muscle activity. Most of the studies are case series and further investigations are required to prove the efficacy of this treatment modality. Thus, in this study, we aimed to investigate the effect of BTX-A injection on the lateral pterygoid (LP) muscle and to evaluate its efficacy regarding TMD. MATERIALS AND METHODS: Thirty-eight patients (19 women and 19 men; mean age of 26.53 years) with painful unilateral temporomandibular joint click and LP muscle tenderness were enrolled in this study. They were divided into two groups; one received an extraoral BTX-A injection in the LP muscle, and the other received a placebo injection. Pain severity, jaw movements, click severity, and Helkimo index were recorded at the first visit, as well as one week, one month, and three months after the intervention. Data were analyzed using repeated-measures analysis of variance and t-tests. RESULTS: The results showed that click severity was not significantly different between the BTX-A and placebo groups (P = 0.07). Pain and Helkimo index decreased significantly in the BTX group (P = 0.00 and P = 0.006, respectively); however, there was no significant difference between the two groups (P = 0.22 and P = 1, respectively). There was a significant difference in lateral movements between the groups (P = 0.00) but not in protrusive movement (P = 0.095). CONCLUSIONS: It can be concluded that although some studies have stated that BTX injection can make the click sound disappear, in this study, we did not find a significant difference between the two groups. Furthermore, our results showed that click and pain severity decreased, but the difference was not statistically significant. Therefore, further studies with a higher dosage of BTX and more participants are recommended. Trial registration The local Ethics Committee of Shiraz University of Medical Sciences approved this research (IR.SUMS.REC. 01/10/2018 and IRCT20130521013406N3).

Protective Effects of the Probiotic Bacterium Streptococcus thermophilus on Candida albicans Morphogenesis and a Murine Model of Oral Candidiasis.

Background: Oral candidiasis is a frequent form of candidiasis, caused by Candida species, in particular, Candida albicans (C. albicans). The transition of C. albicans from yeast to hyphae allows its attachment to epithelial cells, followed by biofilm formation, invasion, and tissue damage. Hence, we investigated the effect of Streptococcus salivarius subspecies thermophilus (S thermophilus) on the growth as well as biofilm and germ-tube formation of C. albicans both in vitro and in vivo in a murine model. Methods: This experimental study was performed in the Department of Medical Mycology and Parasitology, School of Medicine, in collaboration with the Central Research Laboratory and the Comparative Biomedical Center, Shiraz University of Medical Sciences, Shiraz, Iran (2017 to 2018). The inhibitory activity of S. thermophilus against Candida species growth was evaluated using the broth microdilution method, and the inhibition of C. albicans biofilm formation was measured using the XTT assay. The inhibition of C. albicans germ-tube formation by S. thermophilus was evaluated using the plate assay and fluorescence microscopy. The experimental activity of the probiotic bacterium was assessed by culture and histopathological methods in six groups of five mice, comprising those treated with four concentrations of probiotics, fluconazole, and distilled water. The one-way analysis of variance, followed by a Tukey post hoc test, was used and a P value of less than 0.05 was considered significant. Results: S. thermophilus inhibited Candida species growth at concentrations of 16 to 512 µg/mL. This probiotic inhibited the formation of C. albicans biofilms and germ tubes in a dose-dependent manner. S. thermophilus significantly reduced the colony-forming units in the mice receiving 30 mg/mL of this probiotic treatment compared with the control group (P=0.024). The histopathological analysis showed that Candida colonization was diminished in the mice following the administration of the probiotic. Conclusion: Given the inhibitory activity of S. thermophilus against the growth, transition, and biofilm formation of C. albicans, it could be used in the management of oral candidiasis.

Antifungal Activity of Xylitol against Candida albicans: An in vitro Study.

AIM: The most common fungal infection among human population is candidiasis, the etiology of which is mostly Candida albicans. As a result of a disrupted balance of the normal flora or a compromised immune system, Candida species can become pathogenic. Various in vitro surveys have shown that glucose intake is a promoter of C. albicans growth, whereas in vivo studies have found that xylitol can decrease the risk of candidiasis and angular cheilitis. Hence, we aimed to evaluate for the first time the inhibitory effects of xylitol on C. albicans by assessing its minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). MATERIALS AND METHODS: The standard strain of C. albicans was acquired. The fungi were incubated in supplemented brain-heart infusion broth for 48 hours at 37°C. The MIC was measured according to the Clinical and Laboratory Standards Institute (CLSI) M100-S24 standard. Microdilution method was applied using 360-uL sterilized polystyrene flat-bottomed 96-well plates. The antimicrobial effects were examined by the microbroth dilution method according to the CLSI M100-S24 standard. RESULTS: The MIC of xylitol for C. albicans was found to be 20 × 104 µg/mL. Furthermore, the concentration of 40 × 104 µg/mL with a decrease of 99.95% in the colony-forming units (CFUs) of the microorganism was found to be the MFC of xylitol for C. albicans. CONCLUSION: According to the results of this survey, xylitol has considerable antimicrobial effects. Hence, this substance can be used as an effective element in gums, toothpastes, and antimicrobial mouthwashes, especially in patients with candidiasis. CLINICAL SIGNIFICANCE: By knowing the MIC and MFC of xylitol, this substance can be effectively used in products aimed to cure this fungal infection.

Correlation between Clinical and Histopathological Diagnoses in Oral Cavity Lesions: A 12-Year Retrospective Study.

Objective: Proper diagnosis plays a key role in the treatment and prognosis of all diseases. Although histopathological diagnosis is still known as the gold standard, final diagnosis becomes difficult unless precise clinical descriptions are obtained. So, this study aimed to evaluate the concordance of the clinical and histopathological diagnoses of all oral and maxillofacial biopsy specimens in a 12-year duration. Materials and Methods: Archive files and clinical findings related to 3001 patients who had been referred to the Department of Oral Pathology during a 12-year period were reviewed. The recorded information in files included age, sex, lesion's location, clinical and histopathological diagnoses, and specialty of dentists. Results: Out of 3001 cases included and reviewed in this study, 2167 cases (72.2%) were consistent between clinical and histopathologic diagnoses. Age, sex, and clinician's specialty were indicated to have no significant effect on diagnosis (p values = 0.520, 0.310, 0.281, respectively), but location and type of lesion affected that (p values = 0.040 and 0.022, respectively). In regard to location, the highest concordance of clinical and histopathologic diagnoses was observed in mouth floor lesions, and the lowest one was in gingival mucosa. In terms of lesion category, the highest and the lowest concordance rates belonged to white and red lesions and pigmented lesions, respectively. Conclusion: The results of the present study show that the consistency of clinical and histopathological diagnoses was three times more than their inconsistency, and the accuracy of the clinicians was largely acceptable.

The Antibacterial and Anti-biofilm Traits of the Novel BMAP-27-Melittin Conjugated Peptide Nanoparticle Against Streptococcus mutans: Clinical Isolates from Oral Cavity.

Background & Objective: The spread and development of drug-resistant bacterial strains has prompted the hunt for novel antibacterial polypeptides undergoing conformational changes to confer rapid bactericidal effects. The aim of this study was to evaluate the effect of novel BMAP27-Melittin conjugated peptide- nanoparticle (NP) against Streptococcus mutans as the primary pathogen from subgingival plaques. Methods: Sixty subgingival plaque samples were collected, and 39 S. mutans isolates were identified. The BMAP27-Melittin conjugated peptide was purchased from GenScript Company, USA. Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Biofilm Inhibitory Concentration (BIC), and Biofilm Eradication Concentration (BEC) of BMAP27-Melittin-NP were calculated using the microtiter method. Results: Thirty-nine infected subjects were reported, including 24 males and 15 females (P=0.299). MIC, MBC, BIC, and BEC of BMAP27-Melittin-NP against S. mutans were 1.8, 2.9, 2.1, and 3.8µg/mL, respectively. The mean MBC, BEC, and BIC values were significantly lower among clinical isolates than S. mutans ATCC 35688 standard strain (P=0.032, 0.001, and 0.001, respectively). Conclusion: BMAP27-Melittin-NP demonstrated significant antibacterial and anti-biofilm effects against clinical isolates of S. mutans which can be considered a promising compound to prevent or treat dental caries and eradicate the oral infections.

Spatial Evaluation of Oral Lichen Planus Patients Referred to Shiraz Dental School, Iran: a Medical Geography Approach.

Statement of the Problem: Oral lichen planus (OLP) is an important inflammatory disease concerning its tendency to malignancy. The etiopathogenesis of this disease is still unknown. Medical geography uses geographic techniques to study factors related to location that cause uneven distribution of disease. Purpose: This study was conducted to map OLP in patients referred to Shiraz Dental School with medical geography techniques and investigate any possible relationship between the number of dentists and health-centers in different regions of Fars province with the number of referrals. Materials and Method: In this cross-sectional study, we evaluated the records of OLP patients referred to Shiraz Dental School from 2007 to 2018. Age, sex, place of residence, occupation, level of education, location of involvement, duration, and cutaneous involvement were recorded. The number of dentists and healthcare centers was obtained from the statistical records of Fars province. A Geographic Information System was used for the assessment of the spatial distribution of OLP. Ordinary least squares (OLS) and geographically weighted regression (GWR) indices were used for evaluating the relationship between the number of dentists and health centers with the number of referrals. Results: From 1006 records, 457 were studied, from which 71% were female (age range of 41-60). The regression coefficient was 0.937 for the number of dentists in each county compared to OLP referrals indicating a strong relationship. The regression coefficient was 0.983 for the number of health-centers. According to GWR analyses in Shiraz neighboring counties like Marvdasht, Sepidan, and Sarvestan, there is a positive relationship between the number of dentists and OLP patients. Conclusion: The results revealed that dentists and health care centers had a good cognition of referring patients with OLP (as a premalignant lesion) for definite diagnosis in Fars counties. But both groups need more education in this matter. Moreover, referrals from settlements near Shiraz were more common because of their easier access.

New Strategy of Reducing Biofilm Forming Bacteria in Oral Cavity by Bismuth Nanoparticles.

OBJECTIVE: Enterococcus faecalis and Streptococcus salivarius are the most important species in dental decay and producing biofilm. Treatment with chlorhexidine 2% mouthwash for 7 days is the best way to eliminate these bacteria. However, due to the ability of these bacteria to survive in harsh environments, increasing emergence of bacterial resistance against available antibiotics, and favorable properties of nanoparticles including broad spectrum antimicrobial activity and lower toxicity, we decided to evaluate reducing biofilm forming bacteria in oral cavity by bismuth nanoparticles. MATERIALS AND METHODS: This was a cross-sectional study of 40 samples isolated from the patients visiting dental clinics in Shiraz in 2019. Samples, which showed growth, were cultured on blood agar plates and incubated for the PCR procedure. Nanoparticle powder was dissolved in high-purity water, and the final concentration of bismuth nanoparticles (BiNPs) was measured with a spectrophotometer. Minimum inhibitory concentration (MIC) of BiNPs against E. faecalis and S. salivarius was determined by the microbroth dilution method according to methods for antimicrobial susceptibility tests. Also, bactericidal assays were conducted in a Mueller-Hinton broth medium and reported as the concentration of BiNPs that reduced the viable bacterial count by 99.9%. Statistical analysis was carried out using SPSS 21 and one-way analysis of variance, and P values less than 0.05 were considered significant. RESULTS: MICs of BiNP suspension against Streptococcus salivarius and Enterococcus faecalis were 2.5 and 5 µg/ml, respectively. Minimum bactericidal concentrations (MBC) of BiNP suspension against Streptococcus salivarius and Enterococcus faecalis were 5 and 10 µg/ml, respectively. Antibacterial activity of BiNPs was compared with chlorhexidine 2%. MICs of BiNPs against Streptococcus salivarius and Enterococcus faecalis were one-twentieth less than those of chlorhexidine. MBC of BiNPs against both pathogens was one-tenth less than those of chlorhexidine. CONCLUSION: BiNPs were more effective than chlorhexidine, and MIC and MBC of bismuth nanoparticles are lower than those of chlorhexidine.

Oral Health-Related Quality of Life in Chronic Liver Failure Patients Measured by OHIP-14 and GOHAI.

BACKGROUND: Oro-dental diseases are prevalent in chronic liver failure (CLF) patients. The aim of this study was to evaluate the quality of life associated with oral health in candidates for liver transplant surgery. MATERIALS AND METHODS: The demographic information of 105 end-stage liver cirrhotic patients was collected. All patients were ordered a panoramic view for pretransplant dental evaluation. The DMFT (decayed-missing-filled tooth) index was calculated for dental examination. The model for end-stage liver disease (MELD) was used for the severity of liver disease. The OHIP-14 (Oral Health Impact Profile) questionnaire and GOHAI (Geriatric Oral Health Assessment Index) questionnaire were applied to evaluate the impact of oral disease on the quality of life. RESULTS: A total of 79 patients thoroughly completed the questionnaires; 79.7% were male, 32.9% were over 50, and 25.3% were less than 30 years old. Further, 12.7% smoked, 2.5% were illiterate, 64.6% had not finished school, and 10.1% had university degrees. Almost half of the cirrhotic patients were suffering from the disease for more than 3 years. Most complaints reported by the patients as "very often" were becoming self-conscious (13.9%) and being uncomfortable when eating any foods (13.9%) followed by feeling tense (12.8%). There was no significant difference between gender, smoking, age, and MELD score based on quality of life (OHIP and GOHAI) (P > 0.05). The level of education (P = 0.020), duration of disease (P = 0.017), and DMFT index (P = 0.039) had a significant impact on oral health-related quality of life in CLF patients. An inverse relationship was seen between the DMFT index and the quality of life. CONCLUSION: Oral health has a high impact on the quality of life of cirrhotic patients. The psychological dimension of oral health is the most debilitating factor affecting the quality of life. This shows the importance of professional oral care, oral health, and self-care education in this group of patients.

Assessment of the Antibacterial Effects of Bismuth Nanoparticles against Enterococcus faecalis.

INTRODUCTION: Enterococcus faecalis (E. faecalis) is the most important species in dentistry and plays a significant role in the etiology of persistent apical lesions after root canal treatment. Up to date, the intracanal application of 2% chlorhexidine for 7 days is the best way to eliminate E. faecalis. However, due to the ability of this bacterium to persist and survive in harsh environments, many studies have been directed towards finding an alternative strategy for prevention or eradication of it. This study was conducted to investigate the effect of bismuth nanoparticles on E. faecalis, as an etiologic factor in recurrent root canal infections. METHODS: Forty patients, referred to Endodontic Ward of Shiraz University of Medical Science for endodontic pretreatment, provided root canal samples. First, all samples were transferred in Enterococcosel broth and incubated. Then, samples which showed growth were plated on blood agar plates and incubated for further PCR procedure. Nanoparticle powder was dissolved in high-purity water, and the final concentration of bismuth nanoparticles (BiNPs) was measured by the spectrophotometer. Minimum inhibitory concentration (MIC) of BiNPs against E. faecalis was determined by microbroth dilution method according to methods for antimicrobial susceptibility tests. Also, bactericidal assays were conducted in Mueller-Hinton broth medium and reported as the concentration of BiNPs that reduced the viable bacterial count by 99.9%. RESULTS: Of all samples, 77.5% revealed the presence of E. faecalis by PCR. Also, E. faecalis growth inhibition was observed at concentrations ranging from 0.625 µg/ml to 20 µg/ml (geometric mean: 2.337 µg/ml), and the MBC values were between 1.25 µg/ml and 40 µg/ml (geometric mean: 4.781 µg/ml), which in comparison with chlorhexidine, these values were about one-eighth of chlorhexidine. CONCLUSION: The experimental data suggest that bismuth nanoparticles could be an interesting alternative to combat E. faecalis, which, in view of the advantages mentioned for bismuth nanoparticle like inhibiting Streptococcus mutans biofilm formation and higher antibacterial activity compared to chlorhexidine, can be suggested to be used in different fields of dentistry.

Evaluation of Antibiotic Resistance Pattern in Dental Bacteremia Detected by Multiplex PCR Technique.

The aim of this study was to detect oral bacteremia and offer the antibiotic resistance patterns. Bacterial resistance pattern was evaluated in 50 patients. A spectrophotometer device equipped with UV and electrophoresis of the extracted samples on agarose gel for antibiogram test were used. PCR test 15 minutes after tooth extraction showed that bacterial strains were extracted from 16 patients. Lactobacillus, Enterococcus faecalis (E. faecalis), Streptococcus sanguinis (S. sanguinis), Streptococcus salivarius (S. salivarius), and Streptococcus mutans (S. mutans) were extracted from 5, 4, 4, 4, and 6 patients. 100% of Lactobacillus, E. faecalis, S. sanguinis, S. salivarius, and S. mutans were sensitive to tigecycline. Most of the Lactobacillus antibiotic resistance was against tetracycline and ciprofloxacin. Antibiotic resistance in S. salivarius was observed in 75% of the cases against piperacillin-tazobactam, ciprofloxacin, and cefotaxime, while in S. mutans was 84% of the cases against ceftriaxone. The results of the current study showed that tooth extraction causes bacteremia before, during, and after tooth extraction. Generally, the highest antibiotic resistance occurred against tetracycline, ciprofloxacin, and ampicillin-sulbactam. In most cases, the bacteria showed partial resistance to these antibiotics; however, tigecycline showed 100% efficacy on all types of bacteria. Streptococcus strains (salivarius, mutans, and sanguinis) were sensitive to most of the antibiotics while antibiotic sensitivity was less evident in Lactobacillus and E. faecalis. Antibiotic resistance has become a critical issue, since it leads to treatment failure when there is a need for antibiotic therapy.

Isolation and Identification of Non- Commensal Pathogenic Bacteria in the Saliva of Patients Candidate for Liver Transplant: A Cross Sectional Study in Shiraz, South of Iran.

STATEMENT OF THE PROBLEM: Liver cirrhosis is the end stage of liver failure. It is mentioned as one of the main etiologies of morbidity and mortality in the world. The human salivary bacteria may induce oral disorders and interact with other body microbiota. PURPOSE: The aim of the present study is to identify the pathogenic bacteria of non-oral origin from the saliva samples of patients with end stage liver failure. MATERIALS AND METHOD: In this cross-sectional study, the saliva samples of 88 end stage liver disease cases and 84 age- and sex-matched healthy subjects were collected. The samples were cultured using gram staining and API20E Kit. RESULTS: According to the statistical analysis, the total amount of the non-commensal bacteria was significantly higher in chronic liver failure (CLF) group than controls (p= 0.001). There was no significant difference between both groups for the presence of other bacteria (p= 0.001) except for Escherichia coli (E. coli). E. coli was isolated from the saliva of 15 cases and only 2 controls. CONCLUSION: Oral cavity may act as a reservoir for enteric bacteria such as E. coli in liver failure patients. Adequate oral and general hygiene might reduce the risk of systemic infection especially in immunocompromised cases.

The Association between Burning Mouth Syndrome and Level of Thyroid Hormones in Hashimotos Thyroiditis in Public Hospitals in Shiraz, 2016.

STATEMENT OF THE PROBLEM: Burning sensation in Hashimoto patient's oral cavity is an unknown prevalent problem. PURPOSE: This study aimed to evaluate the prevalence and intensity of burning mouth syndrome (BMS) in patients suffering from Hashimoto's thyroiditis in all public hospitals in Shiraz, 2016. MATERIALS AND METHOD: A total of 153 patients with Hashimoto's thyroiditis were selected based on simple random sampling. The initial level of thyroid stimulating hormone (TSH), Anti-TPO (thyroperoxidase), Anti-TG (thyroglobulin), Free T3 (triiodothyronine) and Free T4 (thyroxine) serum as the indices of Hashimoto's thyroiditis was assessed. The BMS intensity was measured according to each patient's verbal or nonverbal expression about the pain experience based on visual analog scale (VAS). RESULTS: Based on the clinical evaluation and interview, only 19out of 153 cases (12%) reported BMS. The mean BMS was 3 based on VAS. Statistically significant association was detected between the level of TSH (p= 0.0001), Anti-TPO (p= 0.035), Anti-TG (p= 0.0001), Free T3 (p= 0.0001), Free T4 (p= 0.0001) indices in patients with BMS. Significant association was also observed between the level of Anti-TPO (p= 0.0001), Anti-TG (p= 0.0001), Free T3 (p= 0.0001) and TSH (p= 0.0001) indices and BMS intensity. However, no significant association was found between the BMS severity and Free T4 (p= 0.056). CONCLUSION: The level of TSH, Anti-TPO, and Anti-TG, Free T3, and TSH indices of Hashimoto's patients were associated with the presence and severity of BSM. However, Free T4 level was only associated with the presence of BMS and not the intensity.

Multiplex polymerase chain reaction for detection of bacteremia during dental extraction.

AIM: Incidence of transient bacteremia following dental extractions ranges 30%-70% among adults and 58%-100% in children. This study aims to assess the multiplex polymerase chain reaction (PCR) technique in detection of transient bacteremia during dental extraction. METHODS: Twenty volunteers for dental extraction entered the study. Blood samples were taken at baseline and 30 seconds and 15 minutes after extraction. Five types of bacteria were selected, namely Streptococcus mutans, S. salivarius, S. sanguinis, Enterococcus faecalis and Lactobacillus. Blood samples were evaluated by microbial culture and multiplex PCR. RESULTS: Blood culture showed rates of 0%, 80% and 25% for bacteremia before, during and after dental extraction, respectively. A significant difference was observed between baseline and during extraction. Using PCR, bacteremia was deemed 20%, 100% and 30% before, during and after extraction, respectively, and a significant difference was witnessed between the baseline and during extraction. The highest incidence was at the 30-second mark after extraction, and the most prevalent type of bacteria was S. mutans. CONCLUSIONS: Multiplex PCR can be used to determine bacterial diversity with high accuracy during occurrence of bacteremia. Therefore, in cases where positive blood cultures only indicate the presence of one species, we recommend the use of this method to detect more diverse bacteria types.

Observational Molecular Case-Control Study of Genetic Polymorphisms 1 in Programmed Cell Death Protein-1 in Patients with Oral Lichen Planus

Background: The association between programmed cell death protein 1 (PD-1) variations and susceptibility to autoimmune diseases has been recurrently reported. However, there is no report about its relationship with oral lichen planus (OLP) as one of autoimmune diseases. Methods: We investigated the association between genetic predisposition to OLP and two single nucleotide polymorphisms in PD-1. Results: GG, GA, and AA genotypes at position +7146 were found in 59 (80.8 %), 10 (13.7 %), and 4 (5.5 %) patients, and in 132 (77 %), 34 (20 %), and 5 (3 %) healthy participants. CC, CT, and TT genotypes at position +7785 were found in 32 (43.8 %), 35 (47.9 %), and 6 (8.2 %) patients and in 99 (58 %), 66 (39 %), and 6 (3 %) controls. Analysis indicated that patients' genotypes were not statistically different from controls' genotypes at both positions +7146 (P = 0.35 and P = 0.98) and +7785 (P = 0.07 and P = 0.06). Conclusion: The findings indicated that PD-1 SNPs at +7146 [PD-1.3] G/A and +7785 [PD-1.5] C/T was not associated with susceptibility to OLP. However, further research with higher sample size and in different geographical regions is needed in order to achieve the generalizability of the findings.

Knowledge and attitude of general dentists regarding common emergencies in dental offices: A cross-sectional study in Shiraz, Iran.

BACKGROUND: Medical emergencies are likely to occur in dental offices due to the use of anesthetics, anxiety, and systemic complications of the patient. Since such emergencies are life threatening in many cases, preparedness of the dentist is highly required. AIMS: This study was carried out to evaluate the dentists' knowledge and attitude regarding diagnosis and treatment of medical emergencies in dental offices in Shiraz, Iran. METHODS: This cross-sectional study was performed on 150 general dentists in Shiraz with at least 5 years since graduation in 2015. They were asked to complete a validated questionnaire including the dentists' demographic information and inquiries about their performance and knowledge in emergency situations. STATISTICAL ANALYSIS USED: Independent t-test, one-way ANOVA, and Pearson's correlation coefficient were used in this study. RESULTS: According to the inclusion criteria, 105 dentists participated in the study. The mean knowledge and attitude of the dentists was estimated 4.98 (±1.50) out of 10. No significant correlation was detected between age, sex, number of patients per day, and working hours with the knowledge of managing an emergency situation (P > 0.05). Out of the number of studied dentists, 49% had attended training workshops and 90% called for re-attending a workshop. The knowledge score of those who had participated in workshops was significantly higher than those who had not (P = 0.016). CONCLUSION: The results of this study revealed that the dentists' knowledge about emergency situations was average while the knowledge was higher in those who had attended emergency workshops. Thus, retraining courses and workshops must be considered more often for graduated dentists.