Journal of Dental Medicine

Background and Aims: The present investigation was conducted on the evaluation of the microstructure, phase transformation behavior, mechanical properties, and fatigue resistance of nickel-titanium rotary endodontic files. The main purpose of this investigation was to find the effect of microstructural parameters on the performance of these files.
Materials and Methods: Three rotary tools with brand names Denco, Edgeendo, and Eighteeth were studied. To evaluate the microstructure and transformation behavior of tools, metallography, X-ray diffraction, and differential scanning calorimetry methods were used. The bending test was used to check the behavior of superelasticity and memory and the microhardness test was used to evaluate the hardness of the samples. Also, cyclic fatigue behavior in a mold containing a simulated tooth canal was investigated and calculated by parametric statistical analysis. The fracture surface of the samples was also studied by scanning electron microscope.
Results: Analyses revealed the existence of a high volume fraction of R phase in the microstructure of the Edgeendo file. Rotary files with higher volume fraction of martensitic phase showed higher shape memory effect and fatigue resistance. Denco and Edgeendo rotary files with better surface quality and high volume fraction of martensitic phases in the microstructure showed better fatigue resistance compared with the Eighteeth file. In all the results, the P-value was less than 0.05.
Conclusion: Multiphase microstructure containing austenite and martensite together with appropriate phase transformation and hardness of the alloy have key roles on functional properties of rotary files. This study provides dentists with a deeper understanding of the fatigue behavior and mechanical properties of these files, enabling them to make more informed decisions in choosing the appropriate instruments for endodontic treatment.

Background and Aims: The quality of sleep plays a significant role in the academic performance of dental students, especially in the clinical years. Identifying and treating students at risk of sleep disorders can reduce or limit the drop in academic performance. The purpose of this study was to determine the relationship between the sleep quality and educational performance of Rafsanjan dental Student-Iran.
Materials and Methods: The present study was a descriptive-analytical cross-sectional study that was conducted among all dental students in Rafsanjan University of Medical Sciences - Iran. This study was presented to all dental students in Rafsanjan by online questionnaire method on Pressline website. The questionnaire included demographic information and student number along with the Pittsburgh Sleep Quality Standard Questionnaire. The Pittsburgh Questionnaire examines the quality of sleep in the range of 0 to 21. The link of the questionnaire was made available to the students through Telegram, and the GPA of the total students was obtained by using the student number from the Vice-Chancellor of University Education. The data were analyzed with SPSS26 software. First, the data were analyzed with Smironov's kermograph test. The results of this test showed that the data distribution is not normal (P<0.05). Due to the non-normality of the data distribution, non-parametric tests such as K-score, Mann-Whitney, Kruskal-Wallis and Spearman were used.
Results: 151 students participated in the questionnaire of which, 73 were men (48.3%) and 78 were women (51.7%). The mean and standard deviation of the age of the subjects studied was 22.11±2.3 years. The overall average sleep quality score of dental students was equal to 8.13, which according to the questionnaire, students experience poor sleep quality. 86.1% of students had poor sleep quality. Examining the correlation between the sleep quality and academic performance showed that there was no significant relationship between them. Sleep quality had no significant relationship with gender, marital status, place of residence, and entry year (P<0.05).
Conclusion: The results of the present study showed that majority of dental students in Rafsanjan had low sleep quality. Although, there was no relationship between the quality of sleep and academic performance, it seems necessary to pay attention to the sleep status of these students in order to improve their sleep quality, which is an important factor in improving their health by administrators and Rizan health program.

Background and Aims: The foundations of a successful root canal treatment are adequate adaptation of the gutta-percha to the canal wall and the establishment of an impermeable apical seal. Despite the common use of M3 and Neoniti rotary files by dentists, no study has been conducted to examine the compliance of gutta-percha in curved canals prepared with M3 and Neoniti files using CBCT. The present study was designed and compiled with the aim of investigating the adaptation of gutta-percha in curved canals prepared with M3 and Neoniti files by CBCT.
Materials and Methods: This randomized controlled laboratory study was conducted ex vivo on 30 permanent human first molar teeth. The teeth were randomly divided into two groups (the first group with M3 and the second group with neoniti), after finding and fixing the appropriate canal path with the examined rotary files. All groups were filled with Single Cone method using F2 gutta-percha and AH26 sealer. Then, the gutta adaptation was assessed using clinical criteria (visual and radiographic) and after the specimens were evaluated using CBCT. All the images obtained from CBCT were converted into the JPEG format and then entered into image J software. The gap between the canal walls and gutta was measured in each canal, and the obtained data were analyzed using the Mann–Whitney U test.
Results: The results showed that the average and standard deviation of gap in M3 files (0.181 ± 0.089) was higher than that of Neoniti file (0.173 ± 0.033). However, no significant difference in the gutta-percha adaptation in curved canals prepared between the M3 and Neoniti files  was observed (P>0.05).
Conclusion: Considering the acceptable adaptation of gutta-percha in canals prepared with M3 and Neoniti files, the use of these two files is recommended in curved canals.

Background and Aims: The development and regular use of adhesive systems has started to revolutionize many aspects of restorative and preventive dentistry. The success of adhesive restorations highly depends on correct application of them. Therefore, the present study was conducted with the aim of determining the knowledge of dentists in Rafsanjan city (Iran) in choosing correct dental adhesive systems in 2023.
Materials and Methods: In this cross-sectional descriptive study, all dentists working in Rafsanjan city were included. The data was collected by a valid and reliable electronic questionnaire, which included two parts of demographic information (gender, age, place of work and year of graduation) and the 12 multiple-choice questions aimed to assess respondents' knowledge regarding the selection of dental adhesive materials in combination with self-cure or dual-cure composites, anterior and posterior composite restorations, fiber posts, fissure sealants, primary teeth, anterior composite veneers, ceramic laminates, and non-carious cervical lesions. The scoring of this questionnaire was as follows: 0 to 3 correct answers = Low level of knowledge; 4 to 6 correct answers = Moderate level of knowledge; 7 to 9 correct answers = Good level of knowledge; 10 to 12 correct answers = Very good level of knowledge.  The four answer choices included "etch-and-rinse (three-step)", "etch-and-rinse (two-step)", "self-etch (two-step)", and "self-etch (all-in-one bottle)". Then data were analyzed by parametric tests (ANOVA, t-test, and Pearson). The significant level was considered as P<0.05.
Results: Out of 91 dentists in Rafsanjan, 79 (86.8%) participated in the study, of which 35 (46.3%) were men. The average work experience was 3.49±3.96 years for men and 2.98±3.73 years for women. The average knowledge score was 4.38±2.16 out of 12 (4.29±2.23 in men and 4.45±2.12 in women). The results showed that there was no significant relationship between the knowledge score and the gender, age, work experience, and workplace (P>0.05).
Conclusion: According to the results which indicated the insufficient knowledge of dentists in  choosing correct dental adhesive systems, it is suggested to pay more attention on teaching in this field at the dental schools. For graduate dentists, new and practical information about the choice of adhesive systems should be provided by continuous education programs.

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: Incorrect prescription of antibiotics for odontogenic infections can endanger patients' lives. This study aimed to determine the pattern of antibiotic prescription by general dentists in Tehran and to compare it with the guidelines recommended by maxillofacial surgeons at Tehran University of Medical Sciences in 2019.
Materials and Methods: A cross-sectional study was conducted on 141 randomly selected dentists in Tehran. The dentists reported their antibiotic prescriptions for various odontogenic infections by completing a questionnaire. The frequency of prescribed antibiotics was calculated considering the severity of the infection, penicillin sensitivity, pregnancy and lactation status of women, and children. These were compared with the guidelines suggested by 15 maxillofacial surgery specialists at Tehran University of Medical Sciences in 2019. Descriptive analysis and binary logistic regression were used. Data analysis was performed using SPSS software version 25.
Results: Among patients sensitive to penicillin with severe infection, 61% of the dentists prescribed the correct medication. The correct prescription rate was 0% in patients with severe infection, 24.82% in pregnant and lactating women with mild infection, 65.24% in children with mild infection, 62.41% in patients with mild infection and penicillin sensitivity, 36.69% in children with severe infection, and 33.82% in pregnant and lactating women with severe infection. The results showed that older dentists were significantly more likely prescribe antibiotics correctly for odontogenic infections (P=0.036, B=0.28).
Conclusion: General dentists in Tehran did not optimally prescribe antibiotics for odontogenic infections. Therefore, training courses to improve their clinical performance are essential.

Guided bone and tissue regeneration is a common technique used in the treatment of areas around teeth and dental implants. In this framework, barrier membranes are employed to create a suitable environment that promotes new bone growth while preventing the invasion of foreign cellular components into this specific setting. Attributes such as biocompatibility with living tissues, structural integrity, longevity, and user-friendliness constitute the principal criteria for selecting appropriate membranes for this particular application. Given the extensive diversity of membrane types concerning their sources, texture, architecture, and inherent properties, determining the most suitable variant depends on the clinical condition presented by the patient and the specific treatment modality, thereby emphasizing its considerable importance. In recent years, fibrous membranes have garnered particular attention due to their distinctive characteristics. These membranes, made of natural or synthetic fibers, typically exhibit high porosity, which facilitates the ingress of vascular structures and osteogenic cells. Owing to their porosity and flexibility, fibrous membranes are considered exceptionally suitable for the regeneration of maxillofacial and dental tissues, thereby contributing to increase bone volume, guide its growth, and at the same time prevent soft tissue encroachment into the restoration area, which ultimately has a favorable effect on treatment outcomes. On the other hand, due to the complexity and extent of oral infections, new nanotechnological approaches have been proposed in recent years to reconstruct infected sites in dentistry. These strategies, by targeting specific sites and having non-toxic properties, can help deliver antimicrobial molecules, regenerate tissue, and maintain oral health. In this context, nanofibrous membranes serve as multifunctional structures, both in the controlled release of antimicrobial agents and as scaffolds for the formation of nascent tissue. Overall, fibrous membranes, by mimicking the physiological conditions of the organism, create an ideal environment for the growth and healing of bone tissues, leading to improved effectiveness in dental procedures. This article is devoted in detail to a comprehensive review of polymeric and composite fibrous membranes with drug release potential.

Background and Aims: Despite significant advancements in rehabilitation of edentulism with implants, complications such as implant failure before and after prosthetic loading remain concerns. This study aimed to evaluate the frequency of dental implant failure before and after prosthetic loading in some of Yazd dental clinics between 2018 and 2023.
Materials and Methods: In this descriptive cross-sectional study, 1060 patients’ files from three public dental clinics were reviewed. These patients were treated by dental implants between April 2018 and June 2023. The collected data included patients’ age and gender, implant diameter, brand, and placement site, type of prosthesis, and fixture failure after surgical and prosthetic phases. Data were statistically analyzed by independent t-tests and chi-square tests.
Results: The mean age of patients was 55.25 ± 12.37 years and 56.3% were female. The frequency of overall implant failure was 3.4%. The implant failure rate after prosthetic loading was 2.8% in females and 2.3% in males (P=0.47). This rate was 2% and 1.9% for maxillary and mandibular implants, respectively (P=0.5). This amount was 2.4% in molar areas,1.7% and 1.8% in premolar and anterior regions, respectively  (P=0.8). Implant failure rate was 1.3% in overdentures, 5.9% in cement-retained, and 3.2% in screw-retained prosthesis (P<0.001). This amount for implants with a diameter less than 3.75 mm was 2.6% and for those with a diameter more than 4.5 mm was 3.7% (P<0.001). Implants with a diameter less than 3.75 mm had a 2.6% failure rate, whereas those with a diameter greater than 4.5 mm had a 3.7% failure rate (P<0.001). The implants failure rate was 1.6% for Dio brand and 2.5% for Dentis (P=0.5).
Conclusion: The overall implant failure rate in this study was 3.4%, of which 1.5% occurred before and 1.9% occurred after prosthetic loading. The frequency of implant failure after loading was significantly associated with the implant diameter and prosthesis type. This was not related to the patient's gender, implant site, or the implant brand.

 This article presents a challenging case of a 64-year-old man with episodic fever, urticarial rash, and arthralgia, prompting a detailed diagnostic process. Despite initial considerations of adult-onset Still's disease, the atypical symptoms led to further investigations, revealing a periapical abscess through a dental examination. The patient's symptoms significantly improved following dental intervention, challenging the initial diagnostic inclination towards a rheumatological disorder. This case underscores the importance of thorough physical examinations and interdisciplinary collaboration in reaching accurate diagnoses. The ultimate diagnosis of systemic presentation due to an occult dental abscess, highlights the need for a comprehensive approach to medical evaluations, considering various clinical aspects and avoiding diagnostics biases. This case study serves as a reminder of the evolving landscape of medical diagnostics and the continued significance of holistic patient assessments and physical examination as valuable practicing skills.

Background and Aims: Posterior crossbite is a common malocclusion disorder in the primary dentition that affects masticatory function. Therefore, early detection and treatment of crossbite teeth is essential to prevent further dental complications and guarantee proper jaw development. This study investigated a reasonable and computationally efficient diagnostic system for detecting characteristics between children with and without unilateral posterior crossbite in the primary dentition using the surface electromyography (sEMG) activity of masticatory muscles.
Materials and Methods: The present study was an experimental in vitro study that used sEMG signals and support vector machine (SVM) to develop artificial intelligence systems capable of decoding muscle activity for diagnosing the crossbite. The core idea of SVM is to find the optimal separating hyperplane that maximizes the margin between two classes (presence or absence of crossbite disease) in the sEMG signal. In this study, 40 children (4  to 6 years old) were selected and divided into unilateral posterior crossbite (UPCB) (n=20) and normal occlusion (n=20) groups. The sEMG activity of the bilateral masticatory muscles was recorded during two 20-s gum-chewing sequences. Then, the time domain and frequency domain features had been obtained. In this study, eighteen time domain features and nine frequency domain features were employed. Finally, these features were used as inputs to the SVM method for data classification and crossbite disease diagnosis. In this paper, four kernel functions of SVM including linear, 2nd order polynomial, 3rd order polynomial and radial basis function were considered.
Results: Based on the obtained results, the crossbite disease had a significant effect on the EMG signals. The results demonstrated that this disease affected the amplitude of the signal more than the frequency. Therefore, using the time features of EMG signals, the SVM method was able to provide a more accurate prediction of crossbite disease. The findings indicated that the mean absolute value feature achieved a 95% accuracy in predicting posterior crossbite. Finally, the results revealed that the RBF method could exhibit superior performance.
Conclusion: The proposed method can be utilized in clinical applications for diagnoses of unilateral posterior crossbite. The findings of the study showed an influence of crossbite on the electrical activity of the temporal and masseter muscles. Therefore, the crossbite problem can be  reasonably diagnosed by an appropriate learning strategy using EMG signals.

Background and Aims: Recently, the use of the palatal process as a source of autogenous bone graft has been considered. Given the anatomical limitations of this space, the assessment of available bone in this area can play an important role in the correct treatment plan. The aim of this study was to assess the amount and density of available bone for the preparation of autogenous graft from the maxillary palatal process using CBCT (Cone Beam Computed Tomography).
Materials and Methods: This cross-sectional analytical study was conducted by collecting CBCT images from 78 patients referred to one of the maxillofacial radiology clinics in Kermanshah in 2022 and 2023. All the patients had no signs of trauma, impacted teeth, pathological lesions, cleft palate, severe periodontitis, or extensive surgery, and also had all the teeth in the area of interest (right first premolar to left first premolar) and their bone growth was completed (age over 20 years). The CBCT images were collected and analyzed using the ondemand program. Different indices such as the area of each cross-sectional slice, bone volume (main variable) were measured with the help of mathematical formula, bone density, and incisive canal diameter. In order to test the hypotheses, the Smirnov-Kolmogorov test was used to check the normality of data, and since none of our variables were normal, we used Spearman and Mann-Whitney correlation tests.
Results: This study was conducted on 78 subjects with a mean age of 43 years, 39 of whom were female and 39 of whom were male. The mean bone volume obtained was 1.84 cm3. The highest bone density was observed in the lateral incisor region and the mean incisal canal diameter was reported to be 2.68 mm. According to the results of the Spearman test, none of the variables had a significant relationship with the age variable. According to the results of the Mann-Whitney test, there was no significant difference in bone density in the lateral, canine, and premolar tooth areas between men and women. However, available bone volume was associated with gender, and this amount was calculated to be greater in men than in women.
Conclusion: According to the findings of this study, the average bone volume in the anterior region of maxilla was 1.51 cm3 and the highest bone density was in the lateral tooth region. The average incisal canal diameter was 2.68 cm3 and the available bone volume was related to gender and this value was higher in men than that of women. However, there was no difference in the bone density between men and women.

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: 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: To prevent dental caries, investigations have focused on finding new antibacterial and anti-biofilm agents without the drawbacks of the currently used synthetic agents. This study aimed to assess the effect of methanolic extract of Zingiber officinale (Z. officinale) on expression of virulence genes of Streptococcus mutans (S. mutans) using real-time polymerase chain reaction (PCR).
Materials and Methods: In this in vitro study, which was conducted in the year 1402, at the Microbiology Department of the Faculty of Medicine and the Faculty of Dentistry at Shahid Beheshti University of Medical Sciences, the methanolic extract of Z. officinale was obtained by the maceration technique. 10 clinical isolates of S. mutans were obtained from the patients with dental infection. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract against S. mutans were determined by the microtiter plate technique. The effect of extract on the expression of relA, comDE, brpA, gtfC, and spaP virulence genes by the clinical isolates was evaluated by the real-time polymerase chain reaction (PCR) technique. Data were analyzed by the Wilcoxon and Mann-Whitney tests (alpha=0.05).
Results: The mean MIC and MBC of the methanolic extract of Z. officinale against S. mutans were 32±11.8 and 64±26.12 mg/mL, respectively. The extract caused down-regulation of relA, comDE, brpA, and gtfC by 50%, 40%, 70%, and 70%, respectively. It also caused 4 times reduction in expression of spaP gene.
Conclusion: The methanolic extract of Z. officinale caused significant down-regulation of gtfC, brpA, relA, comDE, and spaP genes, indicating its optimal efficacy to control the virulence of S. mutans.

Background and aims: Dental procedures carry a significant risk of transmitting viral and bacterial infections to both patients and healthcare personnel. Patients' awareness of infection control principles can play a crucial role in improving the safety of the clinical environment and promoting public health. This study aimed to assess the level of patients’ awareness regarding infection control principles in dental treatments.
Materials and Methods: This descriptive-analytical cross-sectional study was conducted in 2022 on 390 patients attending the Dental School Clinic of Babol University of Medical Sciences, Iran. Data were collected using a validated questionnaire consisting of 24 items related to infection control. Each correct answer was awarded one point. The total score and awareness level of participants were analyzed based on the gender, age group, educational level, and number of dental visits using independent samples t-test, chi-square test, and ANOVA in SPSS, with a significance level set at 0.05.
Results: The mean age of patients was 33.89 ± 13.24 years and 62.8% were female. The mean awareness score was 18.37 ± 3.21. A total of 76.4% of participants demonstrated a good level of awareness. The awareness mean score was higher in female than male patients (P=0.006). A statistically significant difference was observed in mean awareness scores educational level (P<0.001) and age group (P=0.01). However, no significant difference was found based on the number of dental visits (P=0.867).
Conclusion: Although, the overall level of patient awareness regarding infection control principles was acceptable, gaps remain in certain areas. The implementation of targeted educational programs is recommended to enhance patients’ awareness and to promote infection control practices in dental treatment settings.

Background and Aims: Bimaxillary dentoalveolar protrusion (BDP) is a common orthodontic anomaly characterized by protrusive dental arches and lip prominence. Extraction of the first premolars is a frequently employed treatment approach in these patients. However, the effect of this intervention on Bolton ratios-particularly the overall and anterior ratios-remains unclear. This study aimed to evaluate the impact of first premolar extractions on Bolton ratios in patients with BDP.
Materials and Methods: This experimental study was conducted on archived physical models of 34 Class I patients with BDP and functional lip incompetency (>4 mm) accompanied by lip protrusion, available at the Orthodontics Department of School of Dentistry, Babol, in 2024. All patients had a full complement of teeth from the first incisor to the first molar in each quadrant. After digitizing the models, mesiodistal tooth widths and the overall and anterior Bolton ratios were calculated. Digital simulation of first premolar extraction was performed, followed by reassessment of Bolton ratios. Pre- and post-treatment values were statistically compared using paired t-tests in SPSS (significance level set at 0.05).
Results: Among 34 studied casts, 67.6 % belonged to females. The mean overall Bolton ratio decreased significantly from 90.33 ± 2.23% to 87.72 ± 2.39%, and the anterior ratio declined from 78.19 ± 2.96% to 77.85 ± 3.03% (P<0.001). Additionally, 15 patients exhibited residual space post-treatment, primarily in the mandibular arch.
Conclusion: Based on the results of the present study, first premolar extraction significantly reduced both the overall and anterior Bolton ratios in patients with bimaxillary dentoalveolar protrusion. However, the likelihood of residual space—particularly in the lower arch-should be carefully considered during orthodontic treatment planning to ensure long-term stability and success.

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.