Journal of Dental Medicine

Background and Aims: Improving dental implantation conditions in order to reduce the failure is always desirable for researchers. The aim of this study was to compare two different materials of dental implants from the viewpoint of biomechanical effect after placement and loading in the mandible.

Materials and Methods: A 3D model of mandible was designed in the MIMICS 10.01 software. Then, by using the obtained model, the end part of the mandible was designed in CATIA V5 software and a drilling operation was performed on the cortical bone of mandible by finite element analysis simulation method in DEFORM-3D V6.1 software. Thereafter, the 3D model of created hole was extract from the drilled site and an ITI dental implant model designed in the CATIA V5 software, was placed in the hole. The space remained between the implant and cavity was considered as a newly-formed cortical bone in drilled site after 6 weeks of dental implant placement and the mechanical properties of newly-formed bone were entered to DEFORM-3D V6.1 software. Then, a load was applied on the top surfaces of two dental implant models with the materials titanium and zirconium-2.5% niobium.

Results: The emerged volume changes in newly formed cortical bone around Ti and Zr-2.5 Nb dental implants were measured 0.238 and 0.242 percent, respectively. Furthermore, micro-motion of Ti and Zr-2.5 Nb dental implants were measured 0.00514 and 0.00538 mm, respectively.

Conclusion: The results of this study showed that Ti dental implant created better conditions than Zr-2.5 Nb dental implant in the mandible.

Background and Aims: The objective of this study was the development of a checklist for assessment of students’ clinical skills in the clinical oral medicine. The second aim was the assessment of stake holders’ satisfaction of this checklist in comparison to the routine global rating method.

Materials and Methods: The checklist was developed in an expert panel sessions and the validity and reliability of checklist were assessed by CVI and test-retest method, respectively. All students (n=66) were assessed in 2 groups, one with developed checklist and another with global rating. At the end of the session, the satisfaction’s level of staff and students were analysized using Wilcoxon and Mann-Whitney test and the mean scores of students were analysized using Paired T test.

Results: Content validity index (CV I) of checklist was 0.88. Reliability of checklist confirmed with high correlation coefficient (0.9). Staffs’ satisfaction had no significant difference between the two methods
(Wilcoxon P=0.06). The mean score of students who assessed by checklist was higher than global rating with no significant differences (P=0.06).

Conclusion: Regarding the higher students’ satisfaction from checklist and more attention to component of assessment and more objectivity of this method and also higher score in checklist, it seems that the use of a checklist is more proper method for assessing the students’ clinical skills.

Background and Aims: One of the most effective methods in reducing the prevalence of caries is oral health education. The aim of this study was to evaluate of two educational interventions regarding prevention of early childhood caries on self-reported practice of parents of 2-5-year-old children receiving dental treatment under general anesthesia.

Materials and Methods: In this interventional study, the effects of two different educational interventions
(pamphlet and pamphlet along with reminder) on self-reported practice of parents of 2-5-years-old children receiving dental treatment under general anesthesia was assessed. Thirty seven couples of children and mothers in two groups were randomly selected. Before and three months after interventions, a standard questionnaire regarding self-reported practice of mothers on prevention of early childhood caries was completed by respondents. Moreover, oral examination including Simplified oral hygiene index (S-OHI), dmft, and white spot lesions were rerecorded at the beginning and three months after interventions. At this time in one of the groups reminder phone calls were made every month. Finally, the answers were scored and data were statistically analyzed to be compared in pre- and post-test.

Results: Comparing each of the groups before and after interventions showed that in both groups there were significant differences in mothers’ perception of perceived ability to make child brush his teeth twice a day (P=0.001), and child’s tooth brushing frequency more than once a day (P=0.03). S-OHI had no significant difference after the intervention between two groups. But each group had a significant decrease three months after intervention (P=0.003). Also the mean number of white spots showed a significant decrease before and after intervention in each groups. Regarding mothers’ self-reported practice no significant difference was observed between two groups (P>0.05).

Conclusion: Using pamphlets along with or without reminder as educational measures had similar enhancing effects on the mothers’ self-reported practice on oral health of children within three months.

Background and Aims: According to the research background and need to print CBCT images in case of emergency, this study has been done to compare the quality and accuracy of the two methods of film and paper printing for CBCT images.

Materials and Methods: The study of CBCT images taken from 5 patients was done and the cross-sectional slices on Fotolusio DNP papers and film AGFA were printed. Afterward, the images was exmined by a maxillofacial radiologist. The images’ quality were identified and recorded with anatomical, from 1 to 4 on forms. The accuracy was determined by the diagnosis of alveolar canal area and the comparison with the gold standard. Data were analyzed using independent chi-square and Fisher exact tests’.

Results: The images quality in anatomical landmarks consisting PDL (P=0.02), lamina dura (P=0.006), the inferior alveolar canal (P=0.01) and the filling (P=0.006) had a significant difference. There was no significant difference. For the lower border of the mandible landmark, there was no difference between the two methods of printing. In comparing the diagnostic accuracy between the two methods (P=1).

Conclusion: The results showed that the diagnostic quality in film printing is better than paper printing and the diagnostic accuracy is the same in both methods.

Background and Aims: Dental caries is the most common infectious diseases. Among the oral bacteria, Streptococcus mutans and Streptococcus sobrinus are considered as the main causes of tooth decay. The aim of this study was to evaluate the production of hyperimmune bovine colostrum containing specific antibodies against cariogenic bacteria and its antimicrobial effects on the growth and adhesion of Streptococcus mutans and Streptococcus sobrinus in the laboratory.

Materials and Methods: In this experimental study, three pregnant bovine immunized with killed antigens of strains of Streptococcus mutans, Streptococcus mutans with Streptococcus Sobrinus and Streptococcus sobrinus through intramuscular injections. After delivery, The colostrum samples were collected, and the changes of anti-streptococci antibodies titers in colostrum and serum were determined by agglutination. Also,their antimicrobial effects against the growth and adhesion of oral streptococci were surveyed by the microtiter plate method. Data were analysed by One-Wey ANOVA in SPSS software.

Results: The results showed that in hyperimmunized bovine , the antibodies titers against injected bacteria were from 1.1000 to 1.3000 in sera samples and from 1.320 to 1.1280 in whey of colostrum samples. Colostrum of hyperimmune cows reduced the attachment of Streptococcus mutans and Streptococcus Sobrinus about 69 and 43 percents, respectively and also, the low dilutions of it reduced bacterial growth.

Conclusion:  According to the antibacterial effect immune colostrum on two strains of cariogenic bacteria in vitro, It appears that this material could be useful in the prevention and control of dental caries.

Background and Aims: Traumatic dental injuries (TDIs) are of the most common dental problems in children and adolescents, which usually occur in the anterior segment and have a significant role in patient’s physical and psychological health. Immediate intervention for damaged teeth can elevate the success rate of treatment in TDI. Thus, general dentists’ knowledge and their effective intervention in TDI are important factors in prognosis of traumatized teeth. The objective of this study was to assess the general dentists’ knowledge and awareness regarding the diagnosis and management of traumatic dental injuries.

Materials and Methods: In this cross-sectional study, the questionnaire data were collected from 130 general dentists, including the demographic data and general dentists’ knowledge about TDIs. The data were analyzed using the Student t-test and Analysis of Variance (ANOVA), Spearman’s and Pearson’s correlation coefficient.

Results: The mean score of general dentists’ knowledge was 8.5 ± 1.5 (total score:10) and it was the same between both males and females (P=0.083). Dentists’ work place does not have any influence in their knowledge (P=0.133). Also, there was no statically significant relationship between the age, job experience and dentists’ knowledge (P=0.805). The relationship between the frequency of TDI managed cases and dentists’ knowledge was not significant (P=0.507).

Conclusion: Considering that the overall knowledge of general dentists regarding the management of TDI was sufficient, it could be a good opportunity in treating these injuries. As TDI is a developing science, it is important to motivate general dentists being up to date regarding this matter.

Background and Aims: Taking impression from angulated implants has always been a great challenge in clinic. In this regard, studies on sectional trays are very few. The aim of this study was to evaluate and compare the dimensional and angular accuracy of impressions using full arch and sectional trays.

Materials and Methods: Four implants (4.3 × 12 mm) (Implantium, Dentium) were placed in the first premolar and molar regions of a Kennedy class I mandibular acrylic model with 30° lingual angulation. Twenty open special trays (Full arch & Sectional) were made on the primary cast. The impressions were taken using vinyl polysiloxane (VPS) and were poured with type IV dental stone. The coordinate measuring machine (CMM) was used to measure the dimensional (Z, Y, X) and angular (θ) coordinates of implants. The data were analyzed using and t-test and SPSS 22. Software.

Results: The type of tray had no significant effect on the dimensional accuracy in X, Y and Z axes (P>0.05) and total linear displacement (r); However, it significantly affected the angular accuracy (∆q) (P<0.05).

Conclusion: Sectional tray yields less rotational displacement in impressions made of angulated implants.

Background and Aims: Tooth decay has high prevalence in the world. The use of plant material for the prevention and treatment of this disease for various reasons is considered, due to the increasing resistance of bacteria to antibiotics, the high cost and adverse effects of some chemicals used in dentistry. This study was aimed to determine the antimicrobial effect of alcoholic extract of Pepper (Capsicum annuum) and eggplant skin and cap on the cariogenic streptococci.

Materials and Methods: In this study, the antimicrobial activity of ethanol extract of Capsicum annuum and eggplant skin and cap on the cariogenic streptococci, including Streptococcus mutans, Streptococcus sobrinus, and Streptococcus sanguis by microtitre plate method for MIC (Minimum Inhibitor Concentration) was performed. Data were analyzed by one-way analysis of variance using Prism 5 Graph Pad software.

Results: MIC for the Capsicum annuum and eggplant skin for Streptococcus mutans was 250 mg/ml (SD=0.052), and for the Streptococcus sobrinus and Streptococcus sanguis was 125 mg/ml (SD=0.027). The MIC for the cap eggplant for Streptococcus mutans and Streptococcus sobrinus was 500 mg/ml (SD=0) and for S. sanguis was getting 125 mg/ml (SD=0.159).

Conclusion: This study showed that the herbal extracts of Capsicum annuum and eggplant skin and cap had beneficially antimicrobial effects on all three strains of cariogenic streptococci.

Background and Aims: The exact placement of impression copings in making accurate prosthesis is very important. In some cases, the implants need to be placed deeply subgingival, which could reduce the direct vision and ultimately reduce the precision of impression copings and subsequently, delivered prosthesis. This would be the cause of multiple complications such as delivery of ill-fitting prosthesis. The aim of this study was to evaluate the effect of the dental implant placement depth on the accuracy of impression coping connection by students.

Materials and Methods: This in-vitro and experimental study was conducted by 50 senior dental students. Four implants at different depths (0, 2, 4 and 6 mm) were placed in a model. After learning how to mount impression coping on implants, the students were asked to mount impression copings on all four implants. The samples were examined by an experienced prosthodontist using a magnifier with 4x magnification. Data were analyzed by statistical Cochran test (P<0.05(.

Results: The proper adapting rate of transfer copings, in subgingival implants with the depth of 0, 2, 4 and 6 mm were 100%, 62%, 58% and 20%, respectively. Statistically significant differences were observed between all groups (P<0.001).

Conclusion: The results showed that there was an inverse relationship between the increasing depth of the implants in the gingiva and the dentist’s ability to connect the impression copings properly.

Background and Aims: Dental caries is an infectious disease transmitted by multiple factors in the mouth and one of the most common chronic diseases in the world that requires a lot of treatment expenses. The aim of this study was to evaluate the effect of fluoride 0.2% and Fuchs mouthwash (a combination of xylitol and fluoride 920 ppm) against two bacterial growths (Streptococcus mutans and Lactobacillus acidophilus).

Materials and Methods: In this in vitro study, first the well diffusion method and then MIC method (minimum inhibitory concentration) were used. Data were analyzed with Excell (2016).

Results: The results of the MIC method showed inhibitory effect of both mouthwashes in pure concentration (128 μg/ml). However, fluoride was effective in concentration higher than 32 μg/ml for Streptococcus mutans and higher than 2 μg/ml for lactobacillus acidophilus. Fuchs was effective for both bacteria at concentration higher than 64 μg/ml and in lower concentration it was ineffective. The results of the well diffusion test showed the inhibition of fluoride mouthwash in pure concentration on the Streptococcus mutans was (17 mm) and on the lactobacillus acidophilus 24 mm was obtained. In Fuchs mouthwash was zero and it represented effectiveness of fluoride on bacteria and ineffectiveness of Fuchs.

Conclusion: The fluoride mouthrinse in different concentrations, because of having a good inhibitory effect in both methods on Streptococcus mutans and Lactobacillus acidophilus was more effective compared with that of Fuchs mouthrinse.

Background and Aims: Delay in light irradiance can improve the polymeric structure and mechanical properties of resin cement and uniform stress distribution. The aim of this study was to evaluate the effect of light activation modes (immediate, 5 and 10-minute delay) on the push-out bond strength of cemented fiber posts with two types of resin cements in different of root canal regions.
Materials and Methods: In sixty extractedsingle canal and endodontic therapied roots, FRC Postec Plus were cemented with two resin cements, Nexus3 and Panavia F2.0, in three curing methods, immediate, 5, and 10 minute delay. After 24 hours storing in a dark place, they were cut into three sections: coronal, middle and apical. The push-out bond strength test was performed using the universal testing machine. Failure modes were evaluated using stereomicroscope. Data were analyzed by ANOVA and Tukey post hoc test with P<0.05 as the level of significance.
Results: In Nexus3, the immediate light curing had significantly higher bond strength (11.18±4.32) than delay methods (P=0.001). In Panavia F2.0, the 5-minute delay had significantly the highest bond strength (13.34±4.62) (P<0.05). There was no correlation between the different light curing methods and root canal regions. In Nexus3, the coronal region had higher bond strength (11.83±3.7) than that of middle (9.12±3.1) (P=0.015), and middle than of apical (5.65±2.77) (P=0.00), and coronal than that of apical (P=0.002). In Panavia F2.0, there were not significant differences among regions (P>0.05).
Conclusion: Delay in light curing of dual-cure resin cement's had different effects on the push-out bond strength.
 

Background and Aims: The purpose of this study was to evaluate the sealing ability of MTA and cold ceramic by using bacterial leakage method.
Materials and Methods: In this experimental study, fifty human single root extracted teeth were chosen. In group A, 20 teeth were filled with MTA and in group B, 20 teeth were filled with cold ceramic. Five teeth were used as a positive control (obturated using gutta-percha without sealer), and five teeth were used as negative control (obturated using gutta-percha with AH26 sealer and coated with two layers of nail varnish). A bacterial leakage model utilizing Enterococcus faecalis was used for evaluation of the sealing ability. The teeth were placed in test tubes, so that they formed two upper and lower compartments. The cultured bacteria in the upper chamber were in contact with the coronal area of the tooth. The root end was placed in the lower chamber containing sterile culture media. In this case, the filling of the root canal was only the communication path between the upper and lower chambers. In this method, the presence of turbidity in the lower chamber indicated that bacteria had penetrated through barrier and reached the medium. The leakage was measured. The acquired data was analyzed using Chi-square test.
Results: In group A (MTA), 7 samples and in group B (Cold ceramic), 4 samples should the leakage. In regarding the leakage, there was no statistically significant difference between MTA and cold ceramic. (P=0.288)
Conclusion: The results showed that the sealing ability of MTA and cold ceramic was similar as root filling materials.

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: A suitable restorative material must have acceptable mechanical properties. The aim of this study was to evaluate the effect of conventional acidic drinks on the micro-hardness of two dental resins.
Materials and Methods: 48 samples of each of P60 and G-aenial composites were prepared and randomly divided into six groups: Coca-Cola, Fanta, yoghurt drinks, soft beer, Sprites and control groups. The study was in 3 steps: after one day in distilled water and after one day and one week of immersion in beverages per day
(6 hours). The Vickers micro-hardness was then evaluated. Finally, data were analyzed by, t-tests, ANOVA and Tukey tests.
Resultes: Comparing the results between the two groups, a significant difference between the two composite was found. After one day in the water, the average micro-hardness for P60 was of 27.12 (kgf/mm²) and 16.51 (kgf/mm²) for G-aenial amount and these differences were found statistically significant (P=0.0001). For the
6-hour maintenance interval, the average micro-hardness between P60 and G-aenial was statistically significant (P=0.0001). For 42 hours, the average micro-hardness ranged between P60 and G-aenial that were statistically significant (P=0.0004). The stiffness of the P60 composite after 42 hours’ storage in soft beer significantly decreased compared with the control group (P=0.03). G-aenial composite hardness after 42 hours of soaking in the Coca-Cola was reduced significantly compared to yogurt drinks (P=0.02).
Conclusion: As a result, the hardness of P60 composite was higher than that of G-aenial. The hardness of both composites reduced in acidic drinks after one week.

Background and Aims: While there are a lot of information about an illness risk factors, there are still some gaps in understanding factors influencing the progression of disease. Given the important role of psychological factors in physical conditions, the purpose of this study was to compare the cognitive emotion regulation, stress, depression, anxiety, and stress related to life events in people with and without periodontal disease.
Materials and Methods: The type of this study was causal comparative. Research society was all clients referred to dental clinics in Lamerd and Mehr cities, then 50 people with and 50 people without periodontal disease (male and female, 15-49 years old) were selected using purposive sampling. The group without periodontal disease was matched with patient group in terms of demographic characteristics. Both groups completed cognitive emotion regulation questionnaire (CERQ), Depression Anxiety Stress Scale (DASS), and life events questionnaire. Data analysis was conducted with SPSS version 17 using multivariate analysis of variance (MANOVA).
Resultes: Data analysis showed that people with periodontal disease had more stress, depression, anxiety, and stress related to life events than matched control group. The groups had significant differences in the components of self-blame, rumination, positive attention to evaluation and catastrophizing (P<0.05). People with periodontal disease had higher scores in self-blame, rumination and catastrophizing and lower scores in positive attention to evaluating compared with matched control group.
Conclusion: The results showed people who were vulnerable to stressfull situations, depression, and anxiety during their lives, and also use maladaptive emotion regulation strategies, were more susceptible to periodontal disease.