Journal of Dental Medicine

Background and Aims: Despite the reduction of incidence of dental caries in recent years, this disease is common and many efforts were conducted to decrease the prevalence of dental caries. On the other hand secondary caries lesions are the main reason for replacement of direct restorations. Therefore, the aim of the current study was to evaluate suitable methods of preparation and restorative materials to reduce caries recurrence.

Materials and Methods: In this experimental study, eighty human teeth were collected and stored in normal saline. The teeth were soft-tissue debrided and cleaned with water/pumice slurry and rubber cups in a low-speed handpiece. Speciments were randomly divided in two main groups. Cavities were prepared with diamond burs or Er:YAG laser (10 Hz, 300 mJ, 3W). Each group was divided into 4 sub-groups, and restored with a glass-ionomer cement (Fuji IX), resin modified glass-ionomer (Fuji II LC), total etch bonding + composite resin or self-etch bonding + composite resin. The specimens were submitted to pH cycling. Speciments were then sectioned, polished and Vickers microhardness measurements were performed on each specimen. Differences among the medians were analyzed using two way ANOVA test at a 95% confidence level and Tukey test.

Results: Statistical analysis showed significant difference in the type of substrate (enamel, dentin) in both main groups (P<0.0001) but no differences in the caries lesion development between the cavities restored with the same material and prepared with diamond burs or Er:YAG laser.

Conclusion: The Er:YAG laser used for cavity preparation and different types of restorative materials used did not show the ability to guarantee significantly more acid-resistance tooth structure against demineralization.

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: Today, resin composites are one of the most commonly used materials in restorative dentistry. However, failure in resin treatments is also common due to its chemical nature and its high talent for decay recurrence. According to conservative approaches, "conservative" treatments are more likely to be considered than "Replacement" of damaged remedies. The purpose of this study was to compare different surface preparation methods on composite surfaces to achieve the highest bond strength between the old and new composites after accelerated aging.
Materials and Methods: First, composite cylinders with a diameter of 6 and a height of 5 mm were prepared using an incremental technique and a microhybrid resin composite. The specimens were stored in distilled water for 6 months at 37°C and then the surfaces of all aged compsites were roughened using diamond milling followed by phosphoric acid etching. The specimens were randomly subjected into five groups. Group 1: GC Composite Primer. Group 2: Universal bonding containing silane (Kuraray). Group 3: Self etching adhesive (SE bond; Kuraray) Group 4: silane (Ivoclar Vivadent) + Second bottle of SE bond bonding system (Kuraray). Group 5: control group with no treatment. Then, 5 mm incremental of new composite (similar to the aged composite with different color) were placed on the surfaces of specimens, sectioned, and thermocycled for 3000 cycles for the microtensile bond strength evaluation. The specimens were evaluated using a stereomicroscope after failure. Data were analyzed by one-way ANOVA and Post Hoc Tukey test.
Results: The specimens in which silane and SE bond were used showed the highest mean microtensile bond strength and those treated by universal bond showed the least bond strength which were significantly different (P=0.02). All samples had cohesive failure patterns in all groups and the percentage of failures in old and new composites did not differ significantly (P=0.69).
Conclusion: : Based on the results, all surface preparations used in this study could provide an appropriate bond strength for repair of old composite restorations. Also, the microtensile bond strength between the old and new composites was higher than the cohesive strength of resin composite itself. However, the mean microtensile bond strength value for the group treated by universal bond was significantly lower than those treated by silane and hydrophobic containing bonding system.

Background and Aims: Despite patient’s demand increased for tooth color restorations, the stable bond between dentin and composite is a challenge in dentistry. Dentin protease activation is responsible for dentin-resin bond failure. The aim of this study was to determine the best pretreatment agent to inhibit matrix metalloproteinase and increase resin-dentin bond durability.
Materials and Methods: After collecting 24 intact third molars, the dentin surfaces were exposed immediately under DEJ. After acid etching of dentin rewetting was done with CHX 2%, EDC 0.3 M for 60 and water (control group). Then the adhesive (Single bond, 3M ESPE, USA) and composite (Filtek Z250 XT, 3M ESPE, USA) were applied. 48 sectioned dentinal specimens were prepared. The specimens were divided into 3 groups. Each group was divided into 2 sub groups (n=8). In half of each group, the micro tensile bond strength test was done immediately and another part half 6 months. Then, the specimens were evaluated by stereomicroscope and SEM. Statistical analysis was performed using SPSS23 software, two-way ANOVA and multiple Tukey and T-test comparisons. P<0.05 was considered as a significant level.
Results: There were not significant differences between immediate micro tensile bond strength of CHX, EDC and control groups (P=0.97). However, there was significant differences between CHX, EDC compared with the control group (P≤0.0001). Comparison between the immediate and 6-month bond strengths in each group, only in EDC group, there was no significant after 6 months’ difference (P=0.64).
Conclusion: EDC and CHX t did not have any effect on the immediate microtensile bond strength. After 6 months, EDC prevented bond strength deterioration, but the bond strength was decreased after CHX usage.

Background and Aims: Use of computer and internet in our modern and digitalized society is an efficient tool to be up to date and fulfil the information gaps. The aim of this study was to evaluate the extent of computer and internet usage among dental students of Islamic Azad University, Tehran, in 2016.
Materials and Methods: This descriptive study for evaluating access and usage of computer and internet by dental students was done using a researcher-made questionnaire on 401 dental students. Validity and reliability (Kappa: 0.82) of the questionnaire was confirmed. Statistical analysis was done by SPSS22 using descriptive and Logistic regression analyses.
Results: More than 95% of the students had access to the computer and Internet. 45.6% of students reported their skills were in the basic level. The major use of computer among the students was internet but only 13.2% of students used Microsoft Office program. The students used the internet for dental subjects even monthly (34.9%) or weekly (29.4%). Only 9.7% of the students had participated in educational workshop for learning methods of research. The most limitation was internet velocity. Positive correlation was found among prospering ownership status (P<0.001), economic status (P=0.05), level of education semester (P=0.038) and the computer & internet usage (what’s more in terms of access and also in terms of improve information and knowledge).
Conclusion: Based on the results, a higher economic level, higher level of education, and property ownership made better access to the computer and Internet. However, computer skills should be more concerned in educational program.

Background and Aims: Accurate diagnosis of vertical root fracture (VRF) is a fundamental importance in endodontics. Because of poor prognosis of VRF, digital radiographs with two horizontal angles have limitations in VRF detection. Also, Gutta-percha can produce artifacts that impair CBCT scan accuracy. The aim of this study was to compare accuracy of CBCT and digital radiography system in vertical root fracture in endodentically treated teeth.
Materials and Methods: In this study, 60 endodentically treated single teeth were selected and randomly coded. The teeth were divided into two groups: 30 with induced root fracture and 30 with no fracture. CBCT scan and digital radiographs with two horizontal angles with a difference of fifteen degrees for all teeth were performed. Two observers assessed the CBCT images and digital radiographies for presence of VRF. The statistical analysis used in this study was Weighted Kappa.
Results: CBCT had the highest sensivity (75.8) and specificity (90). Digital radiography with 68.3 sensitivity and 79.1 specificity were not as efficient as CBCT (P<0.05).
Conclusion: According to this study, the accuracy of CBCT seems to be higher than that of digital radiography in detecting VRF and provides the most reliable data in comparison of digital radiography.

Background and Aims: Reconstruction of osseous defects is one of the ideal goals of periodontal treatments and dental implant therapy. Different biomaterials have been used for this purpose and many studies have tried to compare and introduce the best ones. The present study aimed to evaluate the effect of PDFDB (Partially Demineralized Freeze-Dried Bone Graft) and FDBA (Freeze Dried Bone Allograft) on the regeneration of rabbit calvarial defects.
Materials and Methods: In this experimental study, 48 similar defects with the diameter of 8 mm were generated in the calvarium of 16 rabbits. Two defects were filled with FDBA and PDFDB, while the other one remained unfilled as the control group. All defects were covered by collagen membranes. 6 and 12 weeks after surgery, the histologic and histomorphometric tests were performed to evaluate the following variables: the rate of new bone formation and its type, the amount of residual grafting material, degree of inflammation and pattern of bone formation. Comparison of osteogenesis percentage and residual biomaterial was performed by repetitive variance analysis, whereas qualitative variables were compared by Friedman non-parametric test.
Results: Regarding bone formation percentage, there was no statistically significant difference between three different groups at 6-week (P=0.33) and also at 12-week time points (P=0.98). The amount of residual material in the PDFDB group was significantly lower than FDBA (P=0.04) in the 6-week samples. However, this difference was not significant in the 12-week samples (P=0.41). Bone quality showed statistically significant difference between graft containing groups and control group after 12 weeks (P=0.01). It means, all samples in FDBA and PDFDB groups displayed lamellar bone after 12 weeks while in control group, only woven bone or a combination of woven and lamellar bone was seen.
Conclusion: FDBA and PDFDB demonstrated similar regenerating effect in the rabbit calvarial bone defects and hastened bone maturation compared to the non-grafted defects.

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.

Conclusion: The trend of publishing scientific articles in Iran in the field of dentistry has been increasing during the selected period. The keywords oral, dental, and pediatric surgery have the most effective and decisive role in the scientific network of dentistry. These keywords provided strong scientific communication amongst the dental scholars in Iran.

Conclusion: The data of this study in proving the anti-biofilm and antibacterial effects of aloe vera extract showed that the expression of the target gene is reduced. It seems that this substance can be used as an alternative to oral hygiene chemicals.

Conclusion: The data of this study in proving the anti-biofilm and antibacterial effects of aloe vera extract showed that the expression of the target gene is reduced. It seems that this substance can be used as an alternative to oral hygiene chemicals.

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: The need to use a highly effective sealer in order to create a complete seal along the canal is essential for the basic treatment of tooth roots. Therefore, the aim of this study was to investigate the sealing ability of cold ceramic and gutta-percha with sealer by applying the bacterial leakage and electrochemical method.
Materials and Methods: In this in-vitro experimental study, fifty human single-rooted teeth were selected and their crowns were cut from the cervical region. The canals were prepared and washed with 17% EDTA. Then the teeth were randomly divided into four groups: group 1 gutta-percha with AH26 sealer (Dentsply Detrey, Germany) (n=20), group 2 cold ceramic (Yazd, Iran) (n=20), negative and positive control groups which each consisted of 5 teeth. Samples were kept in an incubator at 37° C for 48 hrs. Two coats of nail polish were used for covering the root, except for the last 2 mm, and microleakage in the fillings was measured by the bacterial leakage and electrochemical methods. The microleakage of the two groups was statistically analyzed in the electrochemical technique by Student's t-test, and in the bacterial leakage method by Fisher's exact test.
Results: In bacterial leakage method, in the first group (gutta-percha) 7 samples (35%) and in the second group (cold ceramic) 3 samples (15%) had bacterial leakage, but no significant difference was observed between the two groups on different days (P>0.05). The mean microleakage based on the electrochemical technique in gutta-percha was significantly higher than that of cold ceramic (P=0.0001).
Conclusion: According to the lower microleakage values in the use of cold ceramic compared to gutta-percha, cold ceramic  can be used to fill root canals to reduce microleakage, although further studies are needed.

Background and Aims: Finishing and polishing of composites is a critical step influencing the clinical service of restorations. The aim of this article was to evaluate and compare the effect of two liquid polishes on the polish retention of two nanocomposites.
Materials and Methods: Eighty standardized disk-shaped specimens (4×2 mm) were prepared from two nanocomposites (n=40), including one nano-filled composite (Filtek Z350 XT-3M ESPE, USA) and one nano-hybrid composite (Aelite Aesthetic Enamel-Bisco, Inc. Schaumburg, USA). The specimens were randomly divided into 4 subgroups (n=10) based on the method of finishing (F) and polishing (P) procedures: M: as control, polymerized under Mylar strip; S: finish and polish with a sequence of Sof-Lex discs (3M ESPE, USA); SP: finish and polish with Sof-Lex discs and use of Permaseal liquid polish (Ultradent products, Inc. USA); SB: finish and polish with Sof-Lex discs and use of Biscover liquid polish (Bisco, Inc. Schaumburg, USA). The specimens were undergone pH cycling and brushing machine and then, the average surface roughness (Ra) and average profile changes along the desired area (Rz) of the specimens were determined with profilometer instrument. Two-way and one-way analysis of variance (ANOVA) was used to compare the mean of surface roughness. Then, Tukey test was used to identify the groups responsible for the difference and t-test was used to compare the mean of surface roughness.
Results: The type of composite and the method of polishing procedure had no effect on the mean Ra (P=0.733) but it had significant effect on Rz1 factor (P=0.025).
Conclusion: Using liquid polish after polishing discs had no effect on the polish retention of nanocomposites.

Background and Aims: The aim of this study was development and validation of a questionnaire measuring the pseudo-scientific unsupported of Iranians’ belief regarding oral health.
Materials and Methods: A list of 169 pseudo-scientific and invalid Iranian beliefs about oral health that was collected in the previous phase of the study were sent to a purposive sample of 13 professors at Mashhad dental school which resulted in extracting 34 beliefs being considered more common among Iranians. A list of 21 pseudo-scientific beliefs was obtained for preparing the questionnaire after receiving the sample opinions of 21 professors of Mashhad dental school about the invalidity and pseudoscientific propositions and their written revision. Finally, the questionnaire was completed by 44 participants to analyze the ease and clarity and to calculate Cronbach's alpha and Kuder Richardson measure as a homogeneity reliability index. It was completed in a group of 15 participants with a time interval of one month for test-retest analysis and consistency reliability evaluation.
Results: A questionnaire consisting of 21 beliefs was developed using four-point, three-point, or two-point Likert scales. The standardized Cronbach's alpha score and Kuder Richardson's measure score were 0.641 and 0.514, respectively, which indicated the moderate to good reliability of the homogeneity. The Interclass Correlation Coefficient (ICC) was calculated as 0.863, representing very good reliability of consistency of the questionnaire. Furthermore, the kappa coefficient of each of the 21 statements had a significant difference with zero (P<0.05) ranging between 0.605 and 1.
Conclusion: The result of the present study is a questionnaire measuring the level of Iranians’ belief in unsupported and invalid statements about oral health. Using this questionnaire would be helpful for dentists and oral health professionals to promote knowledge of Iranians about oral health.

Background and Aims: The aim of this study was to investigate the tooth discoloration caused by cold ceramic compared to MTA Angelus in contact with the washing solutions such as sodium hypochlorite (NaOCl) and normal saline.
Materials and Methods: 50 samples of extracted human maxillary anterior teeth were selected. After preparing the access cavity, they were divided into 4 experimental groups and 1 control group (10 in each group). The access cavities of teeth in groups 2 and 4 were rinsed with 5.25% sodium hypochlorite and those in groups 1 and 3 were rinsed with normal saline. Then, after drying, 3 mm thickness of cold ceramic (groups 1 and 2) and MTA Angelus (groups 3 and 4) were placed in the access cavities of the teeth. After setting of the materials, all specimens were restored with a resin modified glass ionomer. Based on the CIE Lab system, each sample’s total color change (∆E) was obtained before, one, and 90 days after application. Data were statistically analyzed using the Wilcoxon test.
Results: According to the results, there was no statistically significant difference in the average tooth discoloration between the groups filled with cold ceramic and in different time periods (P>0.05). While, in the groups filled with MTA Angelus, the difference in the average tooth discoloration in 90 days after application was significantly higher than one day (P<0.05).
Conclusion: The results of this study showed that compared to MTA Angelus, cold ceramic causes less tooth discoloration over time and therefore, it can be suggested as a more suitable alternative endodontic cement than MTA Angelus.

Background and Aims: Sleep quality may be a predictive factor for temporomandibular disorders (TMD) compared to other risk factors. Patients with TMD may experience quality-of-life problems such as sleep disorders and orofacial pain. Timely diagnosis of TMD can halt its progression in the initial stages and reduce its severity. This study aimed to investigate the frequency and severity of temporomandibular joint disorders and their co-occurrence with sleep quality among dental students in Yazd in 2023.
Materials and Methods: This descriptive study was conducted among 211 students at the Yazd Dental School. The Fonseca and PSQI questionnaires were used to determine the severity of TMD and sleep quality, respectively. Clinical examination was conducted to assess the symptoms of TMD. Additionally, demographic information such as gender, marital status, and place of residence was recorded. The data were analyzed using chi-square and t-tests.
Results: The final analysis was performed on 211 individuals, comprising 118 males (56%) and 93 females (44%). Among all the participants, 204 individuals (83.88%) had at least one symptom of TMD.  The participants' most prevalent symptoms were jaw sounds, midline deviation, pain, and mouth opening limitation. There was no significant difference in the frequency of TMD symptoms, jaw sounds, jaw deviation, and limitation in opening, based on gender. Similarly, the prevalence and severity of TMD and their symptoms showed no significant association with residence or marital status (P>0.05). Although, a correlation was observed between the poor sleep quality and the severity of TMD, no association was found between the presence of TMD symptoms and poor sleep quality (P>0.05).
Conclusion: While, the frequency of TMD symptoms did not differ significantly between genders, the severity of TMD and jaw pain was significantly higher among female students. Individuals with poor sleep quality exhibited significantly higher severe degree of TMD.

Background and Aims: Student perspectives play a crucial role in evaluating educational systems. This study assessed the self-efficacy of dental students at Yazd Dental School in diagnosing and managing oral and maxillofacial pathological lesions.
Materials and Methods: This cross-sectional study was conducted among dental students from semesters 6 to 12. A total of 250 self-efficacy questionnaires, designed to evaluate students' abilities in lesion management, were distributed. The questionnaire covered biopsy procedures, differential diagnosis, and treatment planning. Data were collected using structured self-reporting methods and analyzed through SPSS version 16, employing descriptive and inferential statistics, including chi-square tests. The semester progression, gender, age, academic performance, and marital status were examined for their impact on self-efficacy. According to the mean and standard deviation obtained in this study, the scores were divided qualitatively.
Results: The response rate of the questionnaire was 91.6%. The average self-efficacy score was 80.30±14.72 (out of 150), indicating a moderate level of confidence. Performing biopsies had the lowest self-efficacy, while diagnosing and managing oral ulcers had the highest. Higher-semester students showed significantly greater self-efficacy (P=0.018), whereas variations based on gender, age, academic performance, and marital status were not statistically significant (P>0.05). Increased exposure to the clinical cases and theoretical knowledge contributed to a growth in self-efficacy over time.
Conclusion: Overall, the students demonstrated moderate self-efficacy in lesion management. Higher-semester students benefited from accumulated experience, though specific areas, such as biopsy procedures and lesion diagnosis, which require further emphasis. Future strategies should enhance teaching methods, clinical practice opportunities, and assessment approaches to prepare students for the practical challenges they will face.

Background and Aims: Given the rapid growth of digital technologies in dentistry, assessing dentists’ awareness and attitudes toward this transformation is essential. This study aimed to evaluate the awareness and attitudes of general dentists in Yazd-Iran toward digital dentistry in 2025.
Materials and Methods: In this descriptive-analytical study, 135 general dentists in Yazd-Iran were selected through convenience sampling. Data were collected via an online questionnaire including demographic information and the questions related to awareness and attitude. Dat were analyzed using SPSS version 27 and the statistical analysis tests were Mann-Whitney, Kruskal-Wallis, and Chi-square to examine the variables.
Results: A total of 59 men and 76 women with a mean age of 31.92 ± 7.87 years participated in the study. The mean knowledge score was 7.76 ± 2.77 out of 12. Higher knowledge and a more positive attitude were significantly associated with older age, longer work experience, and male gender (P<0.05). Overall, 74.1% of participants were unaware of the well-known CAD/CAM system, 74.8% were unfamiliar with digital implant software, and 60% did not have adequate knowledge of correct application of intraoral scanners. While, 81.5% reported an overall positive attitude, only 11.9% considered their knowledge to be aligned with modern digital technologies.
Conclusion: General dentists demonstrated a moderate level of awareness and the existing knowledge gaps warrant greater attention in both undergraduate and continuing education. Enhancing knowledge among specific groups-such as younger, less experienced, and female dentists—is essential. Significant differences in attitudes were observed according to the age, gender, and years of professional experience.