Journal of Research in Dental and Maxillofacial Sciences
Volume:10 Issue: 1, Winter 2025

This study aimed to assess the critical thinking skills (CTS) of a group of Iranian dental students.  

This cross-sectional study was conducted on 355 dental students of the Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University in the clinical training period (academic years 3-6) in 2022-2023. The CTS of students were evaluated by using the valid and reliable Persian version of the California Critical Thinking Skills Test (CCTST). Correlations between the CTS total and domain scores with demographic variables were analyzed by the multiple linear regression and Pearson’s correlation tests (alpha=0.05). 

A total of 260 questionnaires were filled out and returned, yielding a response rate of 73.2%. The mean age of the participants was 23.90±2.89 years. There were 60.8% females and 39.2% males. Of all, 74.2% were single, and 25.8% were married. Also, 34.2% had an extracurricular clinical dental practice. The mean total CTS score was 10.66±2.83 out of 34, which had a significant correlation with the academic level (P=0.005), such that the mean CTS score was significantly higher in senior dental students. The mean CTS score had no significant correlation with age, gender, marital status, or extracurricular clinical practice (P>0.05).

The mean CTS score of dental students of the Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University was lower than the standard average, highlighting the need for educational interventions to improve it.

Green synthesis through using plants such as Quercus infectoria (Q. infectoria) is a relatively novel technique for synthesis of nanoparticles. This study aimed to assess the effect of silver nanoparticles (SNPs) green synthesized by using the Q. infectoria extract on some dental pathogens.

In this in vitro study, SNPs were synthesized by using the Q. infectoria extract and silver nitrate. Formation of SNPs was confirmed by UV-visible spectrophotometry. Presence/absence and proliferation of Streptococcus mutans (S. mutans), Streptococcus salivarius (S. salivarius), Streptococcus sobrinus (S. sobrinus), Lactobacillus acidophilus (L. acidophilus), and Enterococcus faecalis (E. faecalis) were evaluated by observing the tube turbidity following their culture in presence of SNPs. Also, different concentrations of Q. infectoria extract (1, ½, ¼, 1/8, and 1/16) were added to 5 bacterial plates, and the diameter of the growth inhibition zones was measured by a ruler. The results were reported descriptively. 

The minimum inhibitory concentration (MIC) of SNPs against L. acidophilus was lower than that for other pathogens. The highest antibacterial effect was observed in concentration of 1 against L. acidophilus, and ½ on S. salivarius and L. acidophilus. Also, L. acidophilus was the most sensitive and E. faecalis was the least sensitive microorganism to ¼, 1/8, and 1/16 concentrations. The 1/16 concentration caused no growth inhibition zone in E. faecalis plate.

Green synthesized SNPs had acceptable antibacterial activity against the tested microorganisms, and may be used as an antibacterial agent against these pathogens.

Considering the importance of skeletal anchorage in orthodontic treatment, this study aimed to assess the frequency and pattern of skeletal anchorage usage by Iranian orthodontists.

In this cross-sectional study, 301 Iranian orthodontists filled out a questionnaire consisting of 10 questions, 5 about miniscrews and 5 about miniplate usage. It also asked for the demographic information of the participants. The relationship between the participants' demographic information and their responses to the questions was also analyzed. Statistical analysis was conducted by the Chi-square test, one-way ANOVA, t-test, and Mann-Whitney test (alpha=0.05). 

There were 46.7% males and 53.3% females with a mean age of 38.9 years and a mean work experience of 8.95 years. Of all, 89.7% of the participants used miniscrews and 16.3% of them used miniscrews and miniplates. Generally, participants not using skeletal anchorage were significantly older (P=0.002) and had a significantly longer work experience (P=0.000). Also, there was no significant association between gender and skeletal anchorage usage (P=0.204). From the perspective of the orthodontists, the main indication of anchorage devices was to provide optimal anchorage.

The results showed that a high percentage of Iranian orthodontists used different types of skeletal anchorage devices. They preferred to use miniscrews more frequently than miniplates, mostly due to difficulties associated with their surgical insertion. Also, it was observed that older orthodontists used skeletal anchorage less frequently than younger orthodontists.

This study compared the fracture resistance and esthetic appearance of reattached incisor tooth fragments with different preparation techniques in simulated crown fractures (CFs).

In this in vitro study, 50 permanent maxillary incisors were randomly divided into five groups (n=10). After induction of uncomplicated CFs, the fractured teeth were restored using five methods (I) simple reattachment (SR), (II) circumferential chamfer (CC), (III) buccal scalloped bevel and lingual bevel (BSB&LB), (IV) buccal and lingual overcontour (BO&LO), and (V) buccal scalloped bevel and lingual overcontour (BSB&LO). After thermocycling, the fracture resistance of the teeth was measured, and their esthetic appearance was assessed using Easyshade spectrophotometer and the United States Public Health Service (USPHS) visual scale. One-way ANOVA, Tukey’s post-hoc test, and paired t-test were used to analyze the data (alpha=0.05). 

The secondary fracture resistance was significantly lower than the primary fracture resistance in the control (P=0.000), CC (P=0.01), BSB&LB (P=0.004), BO&LO (P<0.001), and BSB&LO (P<0.001) groups. The CC group showed a significantly higher secondary fracture resistance than the BO&LO group (P=0.02). Although a more favorable esthetic appearance was observed in the BSB&LB group, no significant difference was found in color difference (∆E) among the groups. Moreover, no statistically significant difference was detected among the study groups regarding the USPHS scale (P>0.05).

Restoration with the CC method may improve the fracture resistance of reattached fragments in simulated CFs in maxillary incisors. However, no considerable difference was found regarding the esthetic appearance among the tested techniques.

This study assessed the position of the second mesiobuccal (MB2) canal relative to the distobuccal (DB) and palatal (P) canals of maxillary molars in an Iranian population using cone-beam computed tomography (CBCT).

This cross-sectional study evaluated 110 CBCT scans of patients retrieved from a radiology clinic in Isfahan, Iran. The MB1-MB2 inter-orifice distance, and the angle formed between the MB1-MB2 line and the DB-P line were measured on reconstructed axial sections. The angulation of MB2 orifice relative to the DB and P canals was categorized as positive, negative, and parallel. Data were compared by Student t-test, Fisher’s exact test, and Chi-square test (alpha=0.05). 

The mean MB1-MB2 inter-orifice distance was not significantly different in first and second molars, in the right and left sides, or in males and females (P>0.05). Negative angulation of MB2 orifice relative to the DB and P canals had the highest frequency (72.7%) followed by positive angulation (23.6%). Angulation of MB2 orifice had no significant correlation with tooth type (first/second molar), laterality, or gender (P>0.05).

The mean MB1-MB2 inter-orifice distance had no significant correlation with tooth type, laterality, or gender. Negative angulation of the MB2 relative to the DB and P canals had the highest frequency, indicating that if a hypothetical line is drawn from the MB1 orifice parallel to the DB-P line, the MB2 orifice would be probably at the distal of this line. Angulation of MB2 orifice had no significant correlation with tooth type, laterality, or gender.

Several studies have investigated the effect of addition of fillers on mechanical strength of denture base materials. This study aimed to evaluate the mechanical properties of heat-cure denture base materials incorporated with different concentrations of zirconia nanotubes (ZNTs).

In this in vitro study, 90 specimens were fabricated from each denture base resin material (Trevlon and DPI) and divided into three groups (n=30) based on the mechanical properties to be tested (flexural strength, impact strength, and surface hardness). Thirty specimens in each group were further subdivided into 5 subgroups (n=6) based on the weight percentage (wt%) of ZNTs (0.0wt%, 0.5wt%, 1.0wt%, 2.0wt%, and 5.0wt%). The specimens were subjected to flexural strength, impact strength, and surface hardness testing using a universal testing machine, IZOD impact testing machine, and Vickers hardness tester, respectively. One-way ANOVA and post-hoc tests were used for statistical analyses (alpha=0.05). 

The maximum flexural strength was observed following the inclusion of 2.0wt% and 1.0wt% ZNTs in Trevlon and DPI, respectively. The maximum impact strength was obtained with the addition of 1.0wt% ZNTs to both Trevlon and DPI. The surface hardness of Trevlon and DPI increased significantly with an increase in the concentration of ZNTs (P=0.005). Flexural strength (P=0.000) and surface hardness (P=0.005) were significantly different among various concentrations of Trevlon and DPI, but the impact strength (P=0.013) was significantly different only in DPI.

The optimal concentration of ZNTs to obtain enhanced mechanical properties of denture base resins was found to be 1.0wt%.

No consensus has been reached on a safe method for disinfection of orthodontic retainers without altering their physical properties. This study investigated the effects of 5.25% sodium hypochlorite (NaOCl) and 10% hydrochloric acid on hardness and surface roughness of thermoplastic orthodontic retainers.

In this in vitro study, 40 samples measuring 10 x 8 x 2 mm were prepared using 1-mm-thick polyethylene terephthalate glycol (PETG) Essix sheets, and randomly divided into 4 groups (n=10). In group A, the samples were immersed in 5.25% NaOCl for 15 minutes followed by immersion in 10% hydrochloric acid for 15 minutes. This process was repeated twice in group B and thrice in group C. Group D served as the control group. Surface roughness was measured by a profilometer, and hardness was measured by a Vickers hardness tester. Data were analyzed by the Kruskal-Wallis, Mann-Whitney, and Bonferroni tests (alpha=0.05). 

Immersion frequency had no significant effect on surface roughness (P=0.096). A significant difference was found in hardness among the groups (P=0.008). The mean hardness of group B was significantly lower than that of group C (P=0.004). The three test groups had no significant difference with the control group in this regard (P>0.05).

According to the results, 15 minutes of immersion in 5.25% NaOCl followed by 15 minutes of immersion in hydrochloric acid for 3 times had no significant clinical effect on the hardness and surface roughness of PETG sheets used for the fabrication of thermoplastic orthodontic retainers.

Oral health neglect could be an indicator of more serious mistakes in medicine. This study was conducted to assess the referral pattern and attitude of physicians towards oral medicine specialty, and their performance in dealing with oral lesions.

In this cross-sectional study, validated questionnaires were administered among 180 medical practitioners with different specialties working in Yazd, Iran. The questions were about the referral pattern, attitude towards oral medicine specialty, and their performance in dealing with oral lesions. Data were analyzed using the Chi-square test, paired t-test, ANOVA, and Pearson’s correlation test (alpha=0.05). 

Of all, 81.1% of the participants had at least one encounter with an oral lesion. One hundred respondents (82.6%) were aware of oral medicine as an independent specialty. The most referred cases were oral lesions in pregnant women (59%), followed by oral ulcers, and red-white lesions (54.1%). The mean score of referral pattern had no significant association with specialty, gender, age, experience, and workplace, but the highest score was acquired by surgeons. The difference in attitude based on specialty was significant (P=0.02), and the highest score was acquired by ENT specialists. Males had a significantly more positive attitude towards oral medicine specialists. There was a significant positive correlation between practice and attitude (P=0.001, r=0.285).

Considering the unfavorable attitude and poor practice of medical specialists, it is time to reiterate and enhance the knowledge of physicians about oral medicine specialty.

The silent sinus syndrome (SSS) is indeed a rare clinical condition. The exact cause of SSS is still unknown, but it is believed to result from chronic negative pressure within the maxillary sinus, leading to progressive inward retraction of the sinus walls and subsequent orbital floor remodeling.

This case report describes a 61-year-old male with slight facial asymmetry and nasal septum deviation with a normal range of vision. According to cone-beam computed tomography (CBCT) findings, the right maxillary sinus appeared hypoplastic and opaque and the right orbit had 4.58 mm displacement compared to the left orbit.

Accurate diagnosis of the SSS requires assessing clinical and radiographic findings. Rhinologists and, to a lesser extent, ophthalmologists and dentomaxillofacial radiologists are skilled at diagnosing SSS through CBCT imaging of the paranasal sinuses. However, general radiologists are not often well aware of this syndrome. Increasing awareness among general radiologists is vital for prompt identification and appropriate care.

Several studies have investigated the application of crossword puzzles in educational sectors. However, little research has particularly addressed their application and effectiveness in dentistry. Therefore, this scoping review aimed to map the current evidence regarding the inclusion of crossword puzzles in dental educational programs and their influence on the educational outcomes of dental students.

We electronically searched the PubMed, Scopus, Embase, and Google Scholar databases and hand-searched pertinent article references to solicit appropriate studies. A narrative synthesis was performed since the studies were heterogeneous in the result parameters. 

Crossword puzzles provide students with an enjoyable and engaging learning experience, improve cognitive skills like comprehension and problem-solving, and promote active learning. They have received substantial backing from dental students for inclusion in the dental curricula.

Incorporation of crossword puzzles and other gamified approaches could be a promising option to enhance dental education practices.