مجله دانشکده دندانپزشکی مشهد
سال چهل و هشتم شماره 4 (پیاپی 131، زمستان 1403)

The space caused by an impacted maxillary canine or missing lateral incisor, can lead to malocclusion and dental crowding. This study aimed to examine the skeletal pattern of patients with impaction or missing of maxillary canine or lateral teeth.

Methods and Materials: 

In this cross sectional study, the panoramic and lateral cephalometric radiographs of 10-25-year-old patients presenting to the Orthodontic Department of Mashhad Dental School over a five-year period were retrieved and analyzed.A total of 103 patients with maxillary canine impaction or missing of the lateral incisor were selected as the case group, and 103 patients without these anomalies were included as controls. After cephalometric tracing, skeletal classes were determined based on SNA, SNB, ANB angles. Facial vertical height was assessed using Jaraback Index. Chi-Square tests and Independent samples T-tests were used for statistical analysis. P-value<0.05 was considered statistically significant

Significant differences in SNA (P<0.001) and ANB (P=0.02) angles were observed between the lateral missing subgroup and control group. No significant association was found between skeletal pattern and gender (P>0.05). Skeletal Class II was the most common pattern in both groups; however, Skeletal Class III was more frequent in males with a missing lateral incisor. Although long facial height was more prevalent in the case group and normal facial height was more frequent in the control group, no significant differences in Jaraback index were observed between the groups (P=0.441).

In this study, skeletal Class II was the most common pattern. Skeletal Class III was more common in males with a missing upper lateral incisor. Tendency to maxillary deficiency was seen in patients with a missing upper lateral incisor.

This study aimed to investigate the clinical and histopathological characteristics of oral and maxillofacial malignancies and their association with the 5-year survival rate of patients in an Iranian population.

Methods and Materials:

 This cross-sectional study analyzed data from 99 patients diagnosed with an oral or maxillofacial malignancy. Patients had admitted to the Pathology Department of Mashhad Dental School from January 2015- January 2019 and their records were retrospectively reviewed. Patients were followed until 5 years after their initial diagnosis and their current status was documented. The patients’ demographic data were collected. The type of malignancy, based on the clinical and histopathologic diagnoses, was recorded. Patient mortality rate and survival time were also calculated. Statistical analysis was performed using Chi-square, Fisher's exact test and Mann-Whitney-U test. Survival analysis was conducted using the Kaplan-Meier method. P-value less than 0.05 was considered statistically significant.

A total of 99 records were reviewed. Gender distribution frequency consisted of 58 male and 41 female patients. Patients had a mean age of 56.8±17.16 years. A total of 48 (48.5%) of patients had died due to oral cancer. The most common malignancies were low-grade SCC (28.3%) and high-grade SCC (25.3%). The most common site of involvement was the tongue (31.3%). The mortality rate in high-grade SCC (68%) was higher than low-grade SCC (35.7%). There was a statistically significant correlation between the type of malignancy and mortality rate (P=0.039). The greatest and lowest median survival time was observed in patients with adenoid cystic carcinoma (60 months) and mucoepidermoid carcinoma (16.8 months), respectively. 

This study provides valuable information about the pattern of oral malignancies, factors related to prognosis, and survival rates in the studied population. The type of malignancy was the only significant factor associated with mortality.

Malocclusion can significantly influence psychological well-being, particularly concerning self-perception of dental aesthetics. The aim of this study was to evaluate the impact of malocclusion severity on the psychological impact of dental aesthetics in adult orthodontic patients.

Methods and Materials:

 This cross-sectional study included a total of 255 healthy adults presenting to Shiraz Dental School and two private dental clinics in Shiraz, Iran. Participants were categorized into a case (undergoing fixed orthodontic therapy) and a control (without malocclusion) group.  Participants were asked to complete the Persian version of the Psychological Impact of Dental Aesthetics questionnaire (PIDAQ). This questionnaire comprises 23 items divided into four domains of Dental self-confidence, Social impact, Psychological impact and Aesthetic concerns. Malocclusion severity was assessed using the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN). Additionally, the type of malocclusion (e.g., Class I, II, III, open bite, deep bite) and the type of orthodontic treatment (e.g., extraction, nonextraction, and surgery) were documented for case group participants. Spearman’s correlation coefficient and LSD-post hoc tests were used to analyze various associations. Statistical significance was established at P-value<0.05.

Participants undergoing fixed orthodontic therapy exhibited significantly higher overall PIDAQ scores and domain-specific scores compared to the control group (P<0.001 for all). There was a significant relationship between the the scores attained for the “Psychological impact” domain and IOTN scores (P=0.023). Subjects who required tooth extraction for orthodontic treatment exhibited significantly greater scores in the Aesthetic concern” domain, compared to nonextraction cases (P=0.031).

PIDAQ scores were significantly greater in orthodontic patients compared to the control group. While the severity of malocclusion was not significantly associated with Dental self-confidence, Social impact, or Aesthetic concern scores, the type of orthodontic treatment influenced Aesthetic concern scores. These findings underscore the psychological benefits of orthodontic treatment.

The evaluation of radiomorphometric indices of the mandible can aid dentists not only in forensic investigations but also in diagnosing developmental abnormalities, age-related changes, and gender-specific characteristics that are crucial for treatment planning. This study aimed to evaluate radiomorphometric indices of mandibular bone on panoramic radiographs for estimating gender and approximate age.

Methods and Materials:

 In this descriptive-cross-sectional study a total 180 panoramic radiographs were retrieved from the Oral and Maxillofacial Radiology Department of Yazd Dental School. Seven different indices were measured: upper ramus breadth (URB), lower ramus breadth (LRB), Condylar ramus height (CH), Projective ramus height (PRH), Coronoid ramus height (CRH), the Gonial angle (GA) and Antegonial notch (AN). Linear and angular measurements were performed on the images. Data analysis was conducted using SPSS 17 with ANOVA, t-tests, linear regression, and logistic regression.

The panoramic radiographs were taken from 90 male and 90 female patients with a mean age 39.29 ±15.9 years. For age estimation in males, the most important indices were the AN, GA, PRH, and CRH. In females, the CRH and LRB were the most relevant indices. For gender determination, the AN, PRH, CRH, and CH indices can be used in descending order of significance. Using the prediction equation, gender determination accuracy was 77% for males, 86% for females, and 82% overall. Mean values for all parameters were higher in males than females.

Morphometric analysis of mandibular ramus indices on panoramic radiographs is a reliable method for gender determination and age estimation in the Iranian population. These findings support the use of mandibular ramus indices in forensic dentistry for population-specific applications.

Orthodontic treatment involves the use of archwires to apply force to teeth, which can cause pain and discomfort for the patient. Pain may be one of the most significant factors deterring patients from continuing orthodontic therapy. The aim of the present study was to comparatively assess pain induced by different-sized nickel-titanium archwires during the first stage of fixed orthodontic therapy.

Methods and Materials:

 This double-blind randomized clinical trial included a total of 81 patients who received fixed orthodontic therapy. Patients were divided in to three equal groups according to the size of the utilized initial archwire (0.012, 0.014, and 0.016 inches). Perceived pain after archwire placement was evaluated using Visual Analogue Scale (VAS). Pain was assessed at three time points, immediately after bracket bonding (T1), 4 weeks (T2) and 8 weeks (T3) thereafter. Pain assessment at each time point was evaluated at four intervals- at placement, 3 hours, 24 hours, and 3 days after the placement of wire. The Repeated Measures ANOVA test was used to evaluate the effects of archwire size and time after placement on reported pain levels.

The results showed that the pain reported in the superelastic nickel-titanium archwires of 0.012, 0.014, and 0.016 inches did not differ significantly from each other during the bonding session, 4 weeks, and 8 weeks after that (with p values of 0.404, 0.181, and 0.800, respectively). In other words, the size of the archwire did not affect the amount of pain caused. However, the intensity of pain over time at each of the mentioned intervals differed significantly (with p values of <0.001, <0.001, and 0.012, respectively), initially increasing and then decreasing over the time period.

Over an 8-week long follow-up period, the size of the arch wire does not affect the reported level of pain, but the intensity of pain varies over time and follows a non-linear pattern, increasing at the beginning of the time period and then decreasing.

 Critical thinking refers to a discipline that enables students to deal with social, scientific, and practical problems effectively. This study aimed to compare the critical thinking skills of first-year and fourth-year dentistry, civil engineering and law students.

Methods and Materials:

 This research was conducted from January 2021 to 2022. Dental students were recruited form Mashhad University of Medical Sciences, Mashhad, Iran. Civil engineering and law students were recruited from Ferdowsi University, Mashhad, Iran. All participants were either first-year or fourth-year students. Students were enrolled by a census sampling method. The Persian version of the California Critical Thinking Skills Test (CCTST) questionnaire was used for data collection. The validity and reliability of this questionnaire have been previously confirmed. The complete score for this questionnaire is a maximum of 34. The first part of the questionnaire inquired about the demographic information of students. Participants were asked to complete the web-based questionnaire anonymously. Data analysis was performed using SPSS version 21 employing statistical tests such as one-way ANOVA, post-hoc Tukey, and T-test. The significance level for all analyses was set at 0.05.

The online CCTST questionnaire was distributed among a total of 470 students and completed by 148 (31.4% response rate). Participants acquired an overall mean score of 11.73 ± 3.89. Dentistry students exhibited a significantly higher score than the civil engineering (P<0/001) and law students (P=%24) (13.09 ± 0.46 versus 11.29 ± 0.54 and 10.19 ± 0.49, respectively). The total score of first-year and fourth-year dentistry students was not significantly different.

 The present study showed that the level of critical thinking skills of dentistry, civil engineering, and law students was suboptimal. This problem shows that certain educational practices need to be reviewed, and more attention should be paid to training human and conceptual skills as part of education planning.

This study aimed to evaluate the influence of using tannic acid 20% (TA) and polyacrylic acid (PAA) as dentin conditioning agents on the microshear bond strength (µSBS) of two types of high viscosity glass ionomer cements (HVGICs).

This in vitro study was conducted on 60 extracted human premolars. The occlusal enamel was removed using a high-speed handpiece under water-cooling in order to expose the dentin. A sectioning device was used to create a flat surface of superficial dentin. Samples were randomly divided into two groups (n=30) based on the type of HVGIS used: Fuji II LC CAPSULE or Equia Forte glass ionomers. The samples of each group were randomly divided into three subgroups (n=10) based on the type of surface conditioning received. Prior to applying the glass ionomer cements, the dentine was conditioned with either PAA, TA or a combination of PAA and TA.  A universal testing machine was used to measure the µSBS of each specimen and was recorded in MPa. The mode of failure was evaluated with a stereomicroscope at ×40. Two-way ANOVA and Tukey post-hoc tests were employed to conduct comparisons between different groups. P-value<0.05 was considered statistically significant.

Two-way ANOVA revealed that there was a significant interaction between the type of utilized HVGIC and the dentin conditioning agent (P< 0.001). Pairwise comparison with Tukey’s post-hoc test showed that the differences between the µSBS values of different groups was always statistically significant, except for the difference between groups Fuji + TA and Equia + PAA (P=0.155), and also Equia + TA and Equia + PAA + TA (P=0.09).

Applying polyacrylic acid as a dentin conditioner showed superior results compared to tannic acid in terms of µSBS values and improving the dentin bond performance of the tested HVGICs.

Persistent idiopathic facial pain (PIFP) is one of the chronic pains in the oral and maxillofacial region and its diagnosis has always been challenging. This study aimed to evaluate the diagnostic and therapeutic measures patients underwent before reaching a definitive diagnosis.

Methods and Materials: 

This cross-sectional descriptive study, included patients referred to the pain clinic of Mashhad Dental School from April 2023 to February 2024, whom received a diagnosis of PIFP. In addition to demographic information, the average time between the onset of symptoms and the final diagnosis, the number of consultations before diagnosis and the history of undergone diagnostic and therapeutic measures for pain relief; were recorded. Spearman's correlation test was used to check for any correlation between diagnosis delay time and patients' age, number of previous consultations, and pain intensity score. Investigating the relationship between diagnosis delay and qualitative variables was done using the Mann-Whitney U or Kruskal-Wallis tests, with a significant level of 0.05. 

  A total of 56 patients, consisting of 42 females and 14 males, with an average age of 49.18 ± 14.86 years participated in this study. The average diagnosis delay was 22.37±17.45 months. Before definitive diagnosis, the patients had visited a doctor or dentist on average 6.41 ± 6.53 times and they had taken an average of 2.25 ± 0.94 classes of medication. According to Spearman's correlation test, more consultations before definitive diagnosis had a positive and significant relationship with longer time to visit the pain clinic (P=0.012, r=0.335). The rest of the investigated factors had no significant relationship with the diagnosis delay time.

Our study showed that most patients had undergone dental procedures in an attempt to relieve pain. Despite numerous referrals of patients to general dentists, a very small percentage of patients were referred to the pain clinic; suggesting that professional delay played an important role in delayed diagnosis.

Considering that simply relying on conventional education methods no longer suffices, educational systems have attempted to employ novel and active learning methods in their curriculum.  This study aimed to compare the effectiveness of jigsaw versus lecture-based learning in undergraduate dental students.

Method and Materials: 

A total of 31 undergraduate dental students attending Rafsanjan Dental School, Rafsanjan, Iran were recruited for this study. Students had all taken a course on Oral Medicine and we decided to evaluate their knowledge regarding pigmented oral lesions. Participants were randomly divided to two groups. Each group received a teaching session, one using the Jigsaw method (experimental group) and the other one using a lecture-based approach (control group). Pre- and post-intervention tests were conducted to evaluate knowledge acquisition. Three months after training, all students had to take their final exam and their obtained scores were also recorded and compared. The complete test scores was a maximum of 20. Independent and paired-samples T-tests were used for statistical analysis. P<0.05 was considered statistically significant. 

The experimental and control group obtained a mean pre-intervention score of 6.50±1.16 and 5.80±1.78, respectively (P=0.210). The post-intervention test scores were 9.06±3.24 in the Jigsaw group and 9.73± 2.71 in the lecture group (P=0.538). Both Jigsaw and lecture-based methods significantly improved students’ knowledge regarding pigmented oral lesions, with mean scores demonstrating a significant difference pre- and post-intervention and three months later during the final exam (P<0.001 for all). However, Independent samples T-test revealed that the two groups were not significantly different in terms of the mean scores or the amount of increase in scores at any evaluation interval (P>0.05 for all). 

After a short- and long-term evaluation, using the Jigsaw method for teaching undergraduate dental students about pigmented oral lesions yielded comparable results to the traditional lecture-based learning method.

The acrylic denture base must exhibit minimal water sorption and surface roughness to ensure comfort, aesthetics, oral health, dimensional stability, and strength. This study aimed to compare the surface roughness and water sorption properties of acrylic denture bases fabricated using conventional and CAD/CAM techniques.

Methods and Materials: 

In this in-vitro study, a total of 24 specimens were prepared in disk form (21 mm in diameter and 2.5 mm in thickness). Two sample groups were compared (n=12): heat-cured acrylic resins and CAD/CAM milled acrylic resin. Surface roughness values (Ra) were measured using a contact profilometer before and after polishing. Measurements were conducted at three points and an average value was calculated for each sample. For water sorption assessment, samples were first kept in a desiccator for 24 hours and then the dimensional measurements were recorded using a digital caliper. The samples were immersed in physiological serum and incubated at 37°C and weighed daily until reaching a constant weight, followed by desiccation and daily weighing to determine final constant weight. Water sorption was calculated and reported in µg/cm3. The data was analyzed using Independent samples T-test. The significance level was set at P-value≤0.05.

The average Ra values were significantly lower in the CAD/CAM group compared to the heat-cured group before and after surface polishing (P<0.001 and P=0.003, respectively). Similarly, CAD/CAM milled samples demonstrated significantly lower water sorption rates compared to heat-cured specimens (P<0.001).

The CAD/CAM acrylic dentures exhibited smoother surfaces and lower water sorption rates compared to heat-processed acrylic dentures, making them a more effective choice for denture fabrication.