Journal of Dental Medicine

Background and Aims: Nowadays, oral cancer is considered one of the most important diseases related to oral health. The objective of the present study was to determine the dental students’ knowledge in Isfahan about oral cancer and the comparison of the level of students' knowledge in different years of education.

Materials and Methods: The present study was a cross-sectional-analytical one conducted in 2013. The population of study included the dental students of private and state University of Isfahan which 255 students were randomly selected. The data were collected using questionnaire and were then analyzed using SPSS software program and Kruskal-Wallis and Mann-Whitney.

Results: From private and public dental schools in Isfahan, 56% and 44% of dental students were involved. Regarding performing routine clinical oral examination, 81% of the participants answered positively, which showed no significant difference among the years of education of the participants (P=0.116). Regarding the examination of patients with oral lesions, 46% of them answered positively, which the difference between the years of education was highly significant (P≤0.001).

Conclusion: The findings of the research indicated that the level of knowledge of dental students of Isfahan city regarding the detection of oral lesions was not sufficient. Although, the students did not perform common examinations for exploring oral cancer, they did not have sufficient knowledge regarding some of the risk factors and oral lesions related to cancer. Therefore, it is necessary that a comprehensive curriculum be developed in this regard for their education.

Background and Aims: Cervical tooth hypersensitivity (CTH) is defined as a sharp pain of short term that occurs in dentin exposed to the oral environment. The aim of this study was to evaluate the efficacy of a desensitizing toothpaste containing potassium nitrate (Sensodyne®) for relieving of CTH, when used locally or as tooth paste.

Materials and Methods: 36 patients were enrolled in this study. They were randomly divided into three groups I) Tooth brushing without toothpaste, II) Local application of toothpaste containing potassium nitrate 5%, III) Tooth brushing with toothpaste containing potassium nitrate 5%. Assessment of CTH was done by evaporative (using air and water spray) and cold stimuli at baseline, 1, 3, and six weeks after the treatment. To compare pain changes over time, due to the interaction between the variables of the studied groups and time, one-way ANOVA was used at any time. Due to the difference of variance between groups to compare pairs of groups, Dunnett T3 test was used.

Results: During the study period, no adverse event observed. In all three groups, pain decreased gradually. Local application of toothpaste had the most favorable effect on CTH. Therefore, when compared with that of the first group, the percentage reduction in pain were statistically significant (P=0.03).

Conclusion: Local application of toothpaste containing potassium nitrate as a desensitizing ingredient is a better choice for treatment of CTH than that of application with toothbrush.

Background and Aims: Headache is among the most common complaints in patients suffering from temporomandibular joint disorders (TMD). Thus, it seems that evaluation of patients with headache in terms of temporomandibular joint (TMJ) disorders is necessary. In people with TMD, parafunctional activities play an important etiologic role. Considering the high prevalence of bruxism and TMDs in patients with headache, assessment the accuracy and severity of this association can play a key role in diagnosis and treatment of these two phenomena. The purpose of this study was to investigate the relationship between bruxism, TMD and headache, also assessment the efficacy of TMD conservative therapy with a special approach to self-management in treating patients with headache.
Materials and Methods: Motor searches of Cochrane, Medline and EMbase databases, PubMed, Google Scholar, Uptodate, BMJ clinical Evidence, MD consult and science direct by using of relevant key words were searched for article published between 2000 and 2015. A total of English language abstracts were reviewed, 80 full articles were obtained and among them, 30 relevant articles were reviewed in this study. Because of the high number of studies in this field, we divided the data into four group, bruxism and TMD, TMD and headache, bruxism, TMD and headache, treatment.
Conclusion: Bruxism and temporomandibular disorders are the two main contributing factors in initiation and perpetuation of headache. Treatment of these two phenomena would be effective in the treatment of headache.

Background and Aims: Radiopacity is an essential requirement for all restorative materials. Radiopaque materials allow the dentist to diagnose and assess radiographically the restoration, primary caries, assessment of contours, overhang and secondary caries. The aim of this study was to evaluate the radiopacity of two types of dental bases and liners in comparison whit dental structure using a digital radiography system.
Materials and Methods: Two classes of materials were prepared: 1 mm and 2 mm thickness disks for glass inomer and 1 mm and 0.5 mm thicknesses for dycal. Specimens of enamel and dentine with the same thicknesses were obtained. As a control, an aluminum step wedge was used. Samples were positioned over a phosphor-ray, plate of min ray soredex system, exposed, and the images were analyzed using the contour dent software. ANOVA analysis was used to investigate the significance of differences among the groups. For pairwise comparisons, the Bonferroni test was applied (P<0.005).
Results: 0.5 mm diameter of self-cure and light cure dycal and enamel, presented radio-opacity higher than that of dentine, except for the light cure dycal that had radiopacity lowers than enamel. 1 mm diameter of all the groups presented higher radiopacity than dentin. Light cure and self-cure glass inomer and self-cure dycal presented radiopacity higher than enamel. Enamel showed radipacity higher than light cure dycal in 2 mm diameter self-cure. Light cure glass inomer presented radiopacity higher than that of enamel and dentin.
Conclusion: The increased thickness of the materials evaluated increased their radio-opacity. It was concluded that all the materials had lower radiopaaty than dentin. Only enamel showed higher radiopacity than light-cured dycal.

Background and Aims: For the clinical success of implant-retained prostheses, fitness of matching components and stability of the applied torque to the implant-abutment assembly under dynamic occlusal loading is essential. The aim of this study was to evaluate the torque loss in Co-Cr castable abutments after cyclic loading.
Materials and Methods: 10 castable abutments were cast in Co-Cr alloy with similar size and height. Each specimen was mounted vertically on a separated implant using a 30 Ncm tightening torque. The detorque values of the abutments were evaluated after 10 min. The same tightening torque was applied to the abutments on their corresponding implants and cyclic loading was applied for 500,000 cycles to the implant-abutment assembly. The torque values after cyclic loading were recorded for each specimen. T-test analysis was conducted on scores from the groups.
Resultes: The results of this study showed that the percentage of torque loss in castable abutments was significantly increased after cyclic loading (P<0.001).
Conclusion: Misfit between the castable implant components can cause torque loss before and after cyclic loading. However, it is more appropriate to relate the results of this study to the screw loosening of the above mentioned abutments than judging their clinical performance.

Background and Aims: Regarding the high prevalence of caries and oral dental diseases, especially in the elderly, and the increasing attention of people to using the concept of quality of life, this study was conducted to determine the relation between oral and dental health and the quality of life in elderly people in Yazd.
Materials and Methods: This cross-sectional study was performed using data from the Yazd Public Health Survey (YAHS) with a sample of 9293 people, in 1393-94. All information was collected from 1907 elderly people aged between 60 to 70 years, including quality of life and oral and dental indexes from the comprehensive questionnaire of YAHS. Data were analyzed by independent t-test and Spearman correlation coefficient using SPSS16 software.
Results: There was a significant relationship between the quality of life and oral hygiene (P<0.01). Also, the score of quality of life and oral health was significantly related to education (P<0.01).
Conclusion: This study showed the positive relation between the oral health the quality of life. In addition, there was a quality of life level in the elderly people with poor oral hygiene.

Background and Aims: Erosion is the chemical dissolution of a tooth by acid without bacterial involvement. The purpose of the current study was to investigate the effect of resin infiltration (Icon), MI paste plus, and Nd:YAG laser on the enamel microhardness.
Materials and Methods: 40 enamel samples were obtained from the third molar tooth. Primary microhardness was measured in all specimens. Then, erosion was created using hydrochloride acid on the surfaces of enamel and the microhardness values were measured. The samples were randomly divided into four groups. G1: MI paste plus, G2: MI paste plus+ Nd:YA laser, G3: ICON without etching, G4: ICON with etching. Erosion was induced again by hydrochloric acid and then subjected to thermocycling. Finally, the microhardness of the samples was measured. Statistical analysis was performed using SPSS23 software, one-way ANOVA, multiple Tukey and T-test comparisons. P<0.05 was considered as a significant level.
Results: The microhardness increased in the third stage compared to the second stage in all groups, which was statistically significant (P<0.000). Also, the comparison of the increase of microhardness among groups, except second group with the fourth group, was statistically significant.
Conclusion: All the materials used in this study significantly increased the microhardness of the eroded enamel.

Background and Aims: Providing quality services is one of the important goals of the health system. Dental services and treatments are expensive. The aim of this study was to investigate the factors influencing the perceived quality of dental treatment services.
Materials and Methods: This descriptive-cross study conducted in 2 qualitative-quantitative phases. Data were collected using interviews and pairwise comparison matrix with 20 dentists working in NAJA dental clinics who were selected by targeted sampling. The validity and reliability of the interviews were determined by long-term engagement of their peers and negative case analysis. The validity of the pairwise comparison matrix was determined through the incompatibility rate (>0.1). Data were analyzed by coding and effect intensity tests (R+J), descriptive statistic test (mean, standard deviation) using SPSS23, Maxqda and matlab R2017b.
Results: Content analysis of the interview showed that tangible factors, assurance, trust, and empathy are the factors affecting the quality of dental treatment services. In the second phase, data analysis showed that trust and empathy (28.204), assurance (24.356), and tangible factors (17.798) are the most to the least important factors in the quality of dental treatment services (P=0.1).
Conclusion: Trust and empathy were the most important factors in the quality of dental treatment services. Managers of dental clinics and dentist need to improve the quality of dental treatment services by emphasizing respect for patients in accordance with the promise to act in the field of providing treatments to patients.

Background and Aims: Survival of periodontal ligament (PDL) cells after avulsion is an important factor in treatment prognosis. Grapefruit Seed Extract (GSE) can be a proper environment for preserving periodontal ligament cells. The objective of this study was to analyze the effect of different concentrations of GSE on the proliferation of fibroblast PDL cells.
Materials and Methods: In this study, the undifferentiated PDL fibroblasts were obtained from two human premolars teeth and cultured in Dulbecco’s modified Eagle’s medium (DMEM). The cultured cells were exposed to different concentrations of GSE. The positive and negative control groups were cultured in fetal bovine serum (FBS) 10% and in a medium without FBS 10%, respectively. The plates were incubated for 1, 6, 12, 24, and 48 hrs. The PDL cell viability was assessed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Statistical analysis of data was accomplished using repeated measure ANOVA with Post HOC Tukey, P<0.05 was considered statistically significant.
Results: We found out that among different concentrations of GSE, 1:128 had the most impact on undifferentiated PDL fibroblasts. Although, the cell vitality was higher in the twelfth hour, 1:128 GSE and in the forty-eighth hour, 1:1024 GSE than the positive control group but they were not statistically significant (P>0.05). Furthermore, all the samples were similar to the positive control group in three of the five timeperiods (P>0.05).
Conclusion: GSE was more effective in fewer concentration and longer periods and it had no toxic effect on PDL cells. Therefore, GSE can be considred as a promoting medium in PDL regeneration of avulsed permanent teeth in the future.

Background and Aims: Knowing the depth and type of the teeth impaction with radiographic approaches can guide the clinicians into selecting the most appropriate treatment and prevent surgical complications. Therefore, the purpose of this article was to evaluate the prevalence of canine and premolar impaction in the digital panoramic view of patients referred to Rasht dental school in 2019.
Materials and Methods: This annalistic-descriptive cross-sectional study comprised patients who attended the Faculty of Dentistry, Rasht, Iran in 2019. Dental records and panoramic radiographs of 500 patients were reviewed retrospectively. Demographic information as well as the type and depth of impaction, involved jaw, and also, the associated pathological lesions were recorded. Data were analyzed with SPSS24 version with significant level of P<0.05.
Results: The findings revealed that among 500 individuals (300 (60%) were females and 200 (40%) were males), 35 individuals (7%) had at least one impacted tooth, 80% of impacted teeth were canines and the others were premolars. The most common impaction type, impaction level, and pathological lesion were mesioangular, B, and carries of the adjacent tooth, respectively. A significant relation was not observed between the type and level of impaction with the involved jaw (P=0.15, P=0.99) and also, the relation between the type of pathological lesion and gender was insignificant (P=0.85).
Conclusion: Functional and esthetic complications of impacted tooth can be prevented or declined by on-time radiographic screening.

Background and Aims: Dentists are at risk of musculoskeletal disorders due to their job characteristics. The purpose of this study was to compare the posture and musculoskeletal disorders of dentists with high and low work experience.
Materials and Methods: This analytical cross-sectional study research was conducted on 76 dentists in Urmia city. Based on work experience, the samples were divided into two groups: less experienced (less than 15 years) and experienced (15 years and more). The variables of forward head, kyphosis, round shoulder, and musculoskeletal disorders were compared in two groups. Forward head and round shoulder variables were evaluated by photography, kyphosis variable by flexible ruler, and musculoskeletal disorders were evaluated by Nordic questionnaire. Data analysis was done using descriptive statistics and analytical statistics (Kolmogorov-Smirnov test, Leven test, independent t-test and Yeoman-Whitney test).
Results: The independent t-test results showed that the angle of forward head, round shoulder, and kyphosis was higher in the high work-experience group than that of the low work-experience group (P=0.001). In comparing the prevalence of neck disorders, the results were significant such that the experienced group had more neck disorders (P=0.002). However, in examining the difference in the amount of disorders in other parts of the body, the difference between the two groups was not statistically significant (P>0.05).
Conclusion: Experienced dentists had a higher degree of forward head, round shoulder and kyphosis positions. Although, there are musculoskeletal disorders in both groups of dentists with low and high level of experience, neck disorders were more common in high-experienced dentists than that of low-experienced ones.

Background and Aims: Dental caries and periodontal disease are the most common chronic diseases. Health care workers specially “Behvarz” due to their wide range of duties, have the potential role in delivering education and prevention of dental caries. The purpose of the present study was to assess the perspective of “Behvarz” working in health care centers of Kordkooy city regarding oral health.
Materials and Methods: Focus group discussions was conducted with a convenient sample of “Behvarz” working in health centers of Kordkooy city.  Total number of 26 Behvarz with the mean work experience of 13 years took part in the study. After obtaining informed consent, group discussions performed in- person (2 groups of 7 and 2 groups of 6 participants) in health centers considering universal precautions. Two researchers coordinated the discussions. Five questions proposed on dental service utilization and oral health challenges and data collection continued until saturation obtained. The content of the discussion recorded and transcribed verbatim. For content analysis, two raters independently coded the content; sub-themes and themes were then extracted and consensus obtained.
Results: More than half of the participants were 34 years of age and older. Regarding the challenges related to dental care in health centers, the main themes were; resource limitation, workload, lack of awareness of “Behvarz” role, limited access, economic barriers to prevention and care. Regarding the challenges to prevention, the main themes were; poor knowledge of patients, limited oral health related knowledge of “Behvarz”, and human resources. The main suggestions were emphasizing on the role of schools, mothers and patient education.
Conclusion: Our research showed that despite the important role of “Behvarz” in delivering oral health promotion at the population level, this role is neglected and needs further attention.