Journal of Dental Medicine

Background and Aims: The display of an individual's teeth varies in different facial expressions, which significantly affects the beauty of the lower face and overall appearance. The ideal display of incisors is influenced by lip morphology and is an essential aspect of treatment planning. This study aimed to evaluate the ideal display of incisors at rest in women with different lip forms, as assessed by dentists and laypeople.
Materials and Methods: This was a cross-sectional study that was conducted in 2024 at Babol University of Medical Sciences. 46 dentists and 92 laypeople were selected and included in the study in an easy and accessible way. The distance between the uppermost area from the lower edge of the vermilion of the upper lip to the imaginary line between the two commissures was used to classify the lip shape, which was divided into three categories: straight (0-3 mm), medium (3-6 mm) and long (more than 6 mm). Smile images of three women in the age range of 15-30 years were collected and manipulated, resulting in six new images from each original image with varying degrees of incisor display using Photoshop (a total of 18 images). The designed images were randomly placed in a booklet and given to participants, who scored each image on a scale of zero to 100. The data were analyzed by SPSS software version 22 and using the Mann-Whitney test at a significance level of 0.05.
Results: A total of 138 participants took part in the study, including 46 dentists (33.3%), comprising 17 males (37%) and 29 females (63%), and 92 laypeople (66.7%), including 46 males (50.0%) and 46 females (50.0%). Laypeople gave higher scores to images of straight and moderate lip forms than dentists. However, this difference was not statistically significant (P>0.05). In addition, dentists gave significantly higher scores to all images related to the  long lip form than laypeople (P<0/05). In addition, among laypeople, men gave a higher score than women to images related to straight and moderate lip form, which was statistically significant (P<0.05).
Conclusion: The findings of this study indicated that a 2.5 mm incisal display at rest was suitable for patients with a straight lip form. In general, it can be concluded that by changing the shape of the lip from straight to long, there is a preference for increasing the amount of incisal display in the resting state.

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: Musculoskeletal disorders (MSDs) are among the most common occupational health problems faced by dentists. Given their impact on dentists’ health and performance, the present study aimed to investigate the prevalence of MSDs among general and specialist dentists practicing in Babol, Iran.
Materials and Methods: In this cross-sectional study, the standardized Nordic questionnaire, consisting of general and specific sections, was distributed in person among dentists practicing in Babol, based on data obtained from the local Medical Council. Distribution was carried out after a telephone invitation and confirmation of willingness to participate. The questionnaire included items regarding pain and discomfort in different body regions such as the neck, shoulders, and lower back. The frequency of participants with MSDs was assessed based on gender, right/left handedness, specialty, playing sports, and participating in a specific sport. The mean age, weight, height, body mass index, weekly working hours, and work experience of dentists with and without MSDs were also compared. Data were analyzed using SPSS software version 22, employing independent t-tests, Chi-square tests, and Fisher’s exact test, with a significance level set at 0.05.
Results: Of the 182 dentists approached, 17 declined participation and 5 met the exclusion criteria. A total of 160 dentists (mean work experience: 15.65 ±9.26 years) were included in the study; of these, 100 (62.5%) were male, 95 (59.4%) were general practitioners, and 65 (40.6%) were specialists. The overall prevalence of MSDs in this population was reported to be 90%. The most commonly affected region was the neck (76.4%), while the least affected was the ankle (3%). A statistically significant association was found between engaging in a specific type of regular physical activity and a reduced incidence of MSDs (P<0.001). No significant associations were observed with other variables such as gender, handedness, specialty, or field of specialization (P>0.05). Furthermore, no significant differences were found in the mean height, weight, body mass index, weekly working hours, or years of experience between dentists with and without MSDs (P>0.05).
Conclusion: Musculoskeletal disorders are highly prevalent among dentists in Babol. Given this high prevalence, the development and implementation of educational programs on ergonomics, along with recommendations for targeted physical activity appear to be essential.