Journal of Dental Medicine

Background and Aims: Considering the extensive connections of anatomical components in the head and neck region, it is expected that a change in one of the components of this functional unit will have effects on other parts. The aim of this study was to investigate the effect of correction of class III skeletal relationship with orthognathic surgery on the angles between cervical vertebrae.
Materials and Methods: This descriptive-analytical retrospective study was conducted in 1403 at the orthodontic department of Babol Dental School. 30 patients with class III skeletal malformations in the age group of 18 to 48 years who underwent orthognathic surgery (single jaw or double jaw) and had a good quality lateral cephalometric radiography were randomly selected and available based on entry and exit criteria. Dependent variables including 13 parameters in the cranial (angles of SNA, SNB, ANB and Wits App), cervical (the angle between the OPT and CVT lines with each other and with the true perpendicular line) and craniocervical area (the angle of the OPT and CVT lines with the horizontal planes of the head, including the mandibular and palatal plane) of the head and neck were used to evaluate the angles between the cervical vertebrae. The data were analyzed using SPSS22 software and independent t-test, and in case of non-normality, Will-Coxon test was used.
Results: In this study, a total of 30 samples were examined. None of the measured parameters of the cervical area before and after surgery showed a statistically significant change (P<0.05). By comparing the angles between the cervical vertebrae, the PP/CVT angle in the craniocervical region showed statistically significant changes (P=0.024). The values of PP/OPT, MP/OPT, SN/CVT, and MP/CVT angles increased slightly after surgery, but they were not statistically significant (P≥0.05), which showed a relative increase in the tension of the head on the upper part of the cervical spine.
Conclusion: Changing the position of the jaw following orthognathic surgery could cause head extension, but it had no effect on the position of the first 4 cervical vertebrae.

Background and Aims: Today's working conditions in medical sciences, including dentistry, are changing rapidly. The explosion of scientific information on the one hand and the increase in consumer awareness on the other hand, along with the ever-increasing advances in artificial intelligence and access to the internet and the wide information network, has made health service providers face complex and different conditions. One of the ways to properly respond to the treatment needs of patients is to benefit from the best available evidence and clinical experience and to pay attention to the values and preferences of patients, which is manifested in the form of evidence-based practice. Dentists as members of the group of health service providers, must be familiar with evidence-based dental concepts and procedures and use them in their professional performance. This article discusses the steps of evidence-based dentistry to help empower dentists in the field of clinical decision-making based on the latest research benefiting from the best evidence and improving their clinical practice.
Materials and Methods: To find relevant articles in the field of evidence-based dentistry, PubMed scientific database and Google Scholar search engine were searched from 2000 to 2023 with keywords of Evidence-based dentistry, clinical practice, and decision making. Among the articles searched based on the inclusion and exclusion criteria, 15 articles in English whose main topic was evidence-based dentistry with an educational approach were selected and used to describe evidence-based dentistry and its components.
Conclusion: Due to the complexity of patients' issues and their increasing awareness, it is essential for dentists to possess specialized skills to meet patients' needs in accordance with their expectations and values, while also utilizing research findings.

Background and Aims: Ensuring the long-term stability of orthodontic treatments and preventing tooth relapse remains a significant challenge in orthodontics, often addressed through the extended use of retainers. Given the pivotal role of retainers' physical and mechanical properties in this regard, this study aimed to investigate the tensile strength, flexural strength, and deflection of three distinct types of fixed orthodontic retainers.
Materials and Methods: In this laboratory study, each group comprised 12 samples of twisted, flat, and coaxial retainer wires, each measuring 8 mm in length. These samples were affixed onto the polyethylene blocks using cyanoacrylate adhesive and subsequently subjected to compressive loads using a universal testing machine. The maximum bending strength and deflection rate were recorded from stress-strain diagrams. To evaluate the tensile strength, the identical samples underwent tensile loading. Statistical analysis was performed utilizing SPSS software, employing analysis of variance tests to compare data between groups.
Results: Significant differences were observed in the bending strength (P=0.004), deflection (P<0.001), and tensile strength (P<0.001) among the investigated retainer wires. The flat retainer wire exhibited the highest bending strength, averaging 822.876±136.07 MPa, while the coaxial retainer wire showed the lowest, with an average of 673.65±73.35 MPa. Regarding deflection, the flat retainer wire displayed the highest average at 4.04±0.6 mm, surpassing the other two types of retainers. However, the tensile strength of the twisted retainer wires, averaging 699.7±83.46 MPa, exceeded that of both the flat and coaxial retainer wires.
Conclusion: The flat retainer wires demonstrated the highest bending and deflection strength, while the twisted retainer wires exhibited the highest tensile strength. Overall, the bending strength, deflection, and tensile strength of the 3-strand twisted and flat retainer wires outperformed those of the 5-strand coaxial retainer wires, increased flexural and tensile strengths imply a higher resistance of the wires to the forces induced by harder and more viscous foodstuffs.

Background and aims: Substance abuse is recognized as a serious public health issue. The aim of this study was to comprehensively assess the correlation between the substance use and oral health status  as well as its impact on the quality of life of addicts in a multi-center approach.
Materials and Methods: In this cross- sectional and analytical study in year 2023, individuals with a history of addiction who visited addiction treatment centers in Isfahan province were recruited conveniently and examined through questionnaires (about demographic information, methods of substance use, oral health behaviors, the use of dental services, and perceived oral health) and clinical examinations. The oral health-related quality of life (OHQOL) was assessed using the OHIP-14 questionnaire. Clinical examinations assessed DMFT, gingival index, mucosal lesions, temporomandibular joint disorder, and treatment needs of the individuals. Data were analyzed using ANOVA, t-tests, and linear regression models (α=0.05).
Results: 232 individuals with age of 45 ± 9.9, mostly male (94.8%) and married (68.5%) were recruited. About 50% of individuals never brushed their teeth. A total of 123 individuals (53%) used substances with moderate harm intensity (opium, hashish and cannabis). Pigmentation was the most common oral lesion. The mean DMFT was 19.27 ± 3 and the perceived oral health mean was 4.53 ±2.98 (out of 10). A total of 187 individuals (80.6%) required prosthetic treatment. The mean OHQOL was 15.93 ± 11.6. Functional limitation had the lowest (1.53), and psychological discomfort had the highest score (3.31) among the seven domains of OHQOL. The linear regression model (P<0.001 and R2=24%) found that the use of high-risk psychoactive substances, oral health behaviors, and age contributed to changes in DMFT. The OHIP linear regression model (P<0.001 and R2=36%) revealed that the duration of addiction, perceived oral health, age, self-employment, government jobs, and retirement contributed to changes in OHIP.
Conclusion: Compared to the general population, addicts have poorer oral health behaviors and more oral health problems, which significantly reduce their oral health-related quality of life.

Background and Aims: Oral self-care among health care workers not only increases the oral health of individuals and their patients, but also improves the society's understanding of the prevention methods of oral disease. Therefore, this study aimed to investigate the oral self-care and compare it among dentistry, nursing, and midwifery students.
Materials and Methods: In this cross- sectional study in 2023, the HU-DBI questionnaire (Hiroshima University Dental Behavior Inventory) was applied to compare the oral self-care status among the first and final year students of dentistry, nursing, and midwifery. Volunteer students entered the study by a census sampling method. Data were analyzed using Spearman’s correlation coefficient, Kruskal-Wallis, and Mann-Whitney tests (P<0.05).
Results: In total, 348 students including 67% women participated in the study. No significant differences in the  mean score of oral self-care were found (P=0.676) among the first-year dental students (5.01±1.71), nursing students (4.81 ±1.81), and midwifery students (4.79±1.63). The mean scores of oral self-care among the final-year students in dentistry, nursing, and midwifery were 6.71±1.59, 5.13±1.62, and 5.17±1.61, respectively. Dental students had a significantly higher score of oral self-care (P<0.001).
Conclusion: Oral self-care among medical students in Azad University of Isfahan was average. Although, dental students revealed a higher level of self-care compared to the nursing and midwifery students, more training in this field is necessary.

Background and Aims: Orphaned children are one of vulnerable groups in society. The aim of this study was to compare oral health, treatment needs, and oral health behaviors of orphaned children under the protection of welfare organization with the guardian children.
Materials and Methods: In this historical cohort study, all 7–12-year-old children under the protection of welfare organization in Isfahan were compared with their classmates’ counterparts in 2019. Clinical examination recorded DMFT/dmft, plaque index, and treatment needs. Children were asked about their oral health behaviors including the frequency of tooth brushing, flossing, fluoride toothpaste, and snacking. Mann-Witney U test, Chi-Squared test, and Fisher's exact test served for  analysis (P<0.05).
Results: The mean score of dmft and DMFT among orphaned children were 3.64±2.54 and 2.93±2.54, respectively, which showed no significant differences with comparison group (P>0.05). No significant difference revealed between the two groups in terms of mean number of deciduous teeth in need of treatment (P=0.175). Only the mean number of permanent teeth requiring treatment was higher in orphaned children (2.46) than that of the comparison group (1.28) (P<0.049). Also, the percentage of children with poor plaque index was higher in orphaned children (P=0.009). There was no significant difference between two groups regarding oral health behaviors (P>0.05).
Conclusion: No significant difference existed between orphaned children and their classmates’ counterparts in terms of dental caries index and oral health behaviors. Only plaque index and the number of permanent teeth requiring treatment was higher in orphaned children. Educational interventions are recommended to promote oral hygiene and to facilitate the orphaned children’s access to dental treatment.

Background and Aims: Dental caries is one of the most prevalent chronic oral diseases worldwide. Timely and accurate diagnosis of dental caries plays a crucial role in preventing lesion progression and reducing complications. This study aimed to systematically review the studies on dental caries detection using machine learning algorithms applied to periapical radiographs.
Materials and Methods: A comprehensive search was conducted in PubMed, Scopus, Web of Science, IEEE Xplore, and Google Scholar databases up to the end of 2024. Inclusion criteria comprised studies using machine learning algorithms for detecting dental caries in periapical or intraoral radiographs. The quality of studies was assessed using the QUADAS-2 tool.
Results: From 825 initial articles, 13 studies met the inclusion criteria. All studies used Convolutional Neural Networks (CNNs) with various architectures including ResNet, VGG, Inception, DenseNet, and YOLO. ResNet-based models and their hybrid variants showed the best performance with diagnostic accuracy ranging from 82% to 98%. Comparison with human experts in 6 studies revealed that deep learning algorithms demonstrated similar or superior performance.
Conclusion: From the results, deep learning especially convolutional neural networks, had significant potential for improving dental caries detection in periapical radiographs. However, challenges such as limited high-quality training data and generalizability issues need further investigation.

Background and Aims: Achieving reliable tools for accurate shade matching of ceramic samples is of great importance in restorative and aesthetic dentistry. This study aimed to evaluate the accuracy of the Trios5 intraoral scanner in determining the shade of ceramic samples using the Vita Classical Shade Guide (VC).
Materials and Methods: This in-vitro study involved scanning each ceramic sample 15 times by two independent observers using the Trios5 intraoral scanner. The detected shade of each sample was compared with the reference shades of the Vita Classical Shade Guide (VC) and the compatibility of the scanner’s results with the reference shades was assessed. The data were analyzed using SPSS24 software and Pearson correlation and paired t-tests and kappa coefficient at a significance level of 0.05.
Results: The highest accuracy of shade detection in both observers was found for shades A2, A3, A3.5, A4, B1, and C4, each with 100% accuracy. The lowest accuracy for both observers was noted for shade A1, with 0% accuracy. The mean overall accuracy for the first and second observers was 64.99% and 63.75%, respectively, with a total overall accuracy of 64.37%. A statistically significant interobserver agreement was observed (P≤0.005).for all shades except B2 (P=0.299).
Conclusion: The Trios5 intraoral scanner can be considered a useful adjunct tool for ceramic shade determination. However, for clinical applications, it is recommended to use it in conjunction with reference tools and complementary methods such as spectrophotometry or visual assessment by experienced clinicians.

Background and Aims: Dry socket is one of the most common complications following dental surgery. Therefore, effective prevention of dry socket can significantly improve patient recovery after tooth extraction. The aim of this study was to evaluate the effect of tranexamic acid combined with a Gelfoam carrier on the prevention of dry socket following surgical removal of impacted mandibular third molars.
Materials and Methods: This parallel randomized clinical trial was conducted in 2023 on 72 patients (40 in the intervention group and 32 in the control group) at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Islamic Azad University, Tehran Unit. In the intervention group, 250 mg of tranexamic acid powder was placed into the extraction socket and covered with Gelfoam, whereas the control group received sterile gauze only. The diagnosis of dry socket was made 2–3 days postoperatively by an independent surgeon. Statistical analysis was performed using the chi-square test, likelihood ratio, and Fisher’s exact test, with a significance level set at P<0.05.
Results: The incidence of dry socket was 7.5% in the intervention group and 34.4% in the control group. All statistical tests demonstrated a significant reduction in the occurrence of dry socket in the intervention group (P≤0.005). These findings are consistent with the physiological mechanism of tranexamic acid in inhibiting fibrinolysis and stabilizing the blood clot, resulting in a marked reduction compared with the control group.
Conclusion: Topical application of the tranexamic acid in combination with Gelfoam following extraction of impacted third molars is an effective, simple, and cost-effective method for the prevention of dry socket. For broader clinical recommendation, further studies with larger sample sizes, comparisons with existing standard preventive methods, and longer follow-up periods are suggested.