Caspian Journal of Dental Research
Volume:10 Issue: 2, Sep 2021

Mental health is an inseparable part of overall health and healthcare workers have experienced mental issues during the COVID-19 pandemic. This study aimed to investigate the amount of stress undergone by dental students and its affecting factors.

This cross-sectional study included all students of Shahid Beheshti Dental School, Tehran. The data on demographic and individual-social characteristics of the participants and questions related to the perceived stress level (PSS-10 questionnaire) were collected using an online questionnaire. The results were analyzed using a T-test and the correlations in SPSS-26 (P<0.05).

A total of 511 students participated in the study. The mean score of the perceived stress level was 15.9 out of 40, indicating a moderate level of perceived stress. Eleven students had suffered from COVID-19 and 13% were in close contact with those infected. Most of the students (72%) used public transportation. About 60% regularly did exercise, and the majority had enough hours of sleep. After examining the relationship between the individual factors and perceived stress level, it was revealed that the PSS was significantly lower in people who had adequate and a regular sleeping timetable (p<0.05). Furthermore, people who had contracted the COVID-19 virus (p=0.019) or had relatives who were infected (p =0.007) experienced higher levels of stress. Suffering from preexisting medical conditions was another significant factor in higher perceived stress levels (p=0.027).

This study indicated that students had gone through a moderate level of stress during the COVID-19 pandemic. People with systemic conditions, sleep disorders, and those who had contracted the COVID-19 virus themselves or their reletives, experienced higher levels of stress. The requirement to provide courses on stress management skills, family awareness, and use of mental health services to reduce the negative effects of this psychological burden is highly recommended .

Enough knowledge of the internal anatomy and apical foramen of a tooth has always been a fundamental prerequisite for root canal therapy. The current study aimed to determine the position and distance of apical foramen to anatomical apex in maxillary anterior teeth in cone-beam computed tomography (CBCT) in the Iranian population.

In this retrospective cross-sectional study, CBCT scans of 250 patients referred to a dental clinic in the city of Babol, Mazandaran province, are investigated. The inclusion criteria were being aged 18 to 70 years, and having maxillary teeth from right canine to left canine. The exclusion criteria were history of trauma in the anterior of maxilla, the openness of the apex, not finding the apex, endodontically treated tooth, surgery in the apical area, and dental anomalies. Maxillary anterior teeth  were examined for apical foramen position and radiographic foramen-apex distance by CBCT in coronal and sagittal planes. Age, gender, and quadrant of teeth were recorded, and their association with radiographic foramen-apex distance was investigated.  Finally, data were analyzed using ANOVA and Independent T-test with P≤ 0.05 was considered significant.

The mean foramen-apex distance in central incisor teeth was 0.53±0.28 mm, in lateral incisor teeth was 0.56±0.31 mm, and in canine teeth was 0.76±0.39 mm. The frequency of apical foramen position in central and lateral teeth was 34.1% and 22.6% centrally, and in canine teeth was 20% distally, respectively. Age and quadrant had no effect on foramen-apex distance. The radiographic foramen-apex distance was higher in men than women, which was statistically significant (P-value=0.003).

Based on the findings, it seems that in the treatment of the root of the anterior teeth of the maxilla, if the working length is considered to be 1 mm shorter than the radiographic apex, it will be better.

Considering the effect of ethnicity and race on the root canal morphology of different teeth, this study was conducted to determine the root canal anatomy of permanent maxillary first premolars using cone-beam computed tomography (CBCT) in an Iranian population.

This descriptive cross-sectional study was performed on 150 CBCT radiographs of an Iranian population, referred to a Radiology Clinic in Rafsanjan, Iran. The CBCT images were evaluated in terms of the number of roots and canals of maxillary first premolar and also canal types in axial and sagittal images. The Vertucci classification was used for assessing the root morphology. Data were collected using a checklist. The independent t-test and Chi-square test were used and analyzed at a significance level of 0.05.

A study of 150 radiographs showed that 81 and 69 ones had one root and two roots, respectively. In terms of canal type in the single-root teeth, 13 radiographs (16%) were type I, 36 (44.4%) were type II, 6 (7.4%) were type III, 17 (21%) were type IV, two (2.5%) were type V, four (4.9%) were type VI, and three (16%) were type VII. It should be noted that none of the radiographs had a type-VIII canal.

This study has indicated that the Iranian population has a complex maxillary first premolars root canal morphology, and according to Vertucci classification, types II and IV are more common; hence, the Clinician must be very careful before treating the root canal of the first maxillary premolars.

The aim of this study was to investigate the effect of different surface treatments on the microtensile bond strength (µTBS) of two types of composite substructures with Vita Mark II ceramics by resin cement.

Sixty-four substructure specimens were molded from two dual-cure composites Core.it and Build-it, equally, and cured by LED light. The specimens of each group were randomly divided into 4 subgroups (n=8) treated by one of HF acid 10%, air abrasion, Er: YAG laser, and one group without any treatment (control group), and then the specimens of each group were bonded to Vita Mark II CAD/CAM ceramic blocks using two Duo-Link and Panavia F 2.0 resin (n=4 and 20 slice in any group). Each final specimen was thermocycled between 5 °C and 55 °C for 2500 cycles and then cut by a slow speed saw to obtain 5 sticks with cross-section dimensions of about 1×1 mm². The µTBS test was done at a speed of 0.5 mm/min by Universal Testing Machine. The fracture pattern was then determined using a stereomicroscope. Statistical differences between groups were determined by one-way ANOVA using Tukeychr('39')s multiple comparison tests.

Among all 16 groups, the highest µTBS was observed in the group with Core.it substructure composite and Duo-link resin cement without any surface treatment and after that in the second step in build-it substructure composite group and Panavia resin cement without surface treatment. The most common fracture pattern in all groups was cohesive in resin cement (P value<0.05).

According to this study, composite substructure surface treatment by hydrofloridric acid, laser and air abrasion reduced µTBS between substructure- ceramic and so  is not recommended.

Palatal rugae is a collection of mucosal folds in front of the palatal and is unique to each individual. Rugae have been studied for various purposes. This research investigates the pattern of palatal rugae with different skeletal relationships in the sagittal dimension in a group of the Iranian population.

A cross-sectional study was examined on 135 pre-orthodontic dental casts. The patients were grouped as Class I, Class II, and Class III according to the Nasion -A to Nasion -B angle (ANB) 45 patients in each group. Palatal rugae were recorded based on length, orientation, and pattern in each group, then compared. Data were analyzed by Chi-square, ANOVA, and Tukey post hoc test. In this study p<0.05 was considered significant.

The mean number of total rugae was significantly different among groups (p value=0.02). Cl III malocclusion had less number of rugae in comparison to other groups (p value=0.03). The number of straight pattern was significantly different between groups, (p value=0.04) and Cl I malocclusion had  more straight pattern than other groups .

This study showed some differences in the palatal rugae pattern between different classes of malocclusion according to Angle’s classificatin. In addition, orientation of some rugae were also found to be significantly different between malocclusion  groups.

The purpose of this study was to compare the Vickers hardness number (VHN) and depth of cure of two types of bulk fill composites in high, low and soft light curing modes.

In this experimental study, 60 cylindrical samples were fabricated from two types of bulk fill composites (Tetric N-Ceram and X-tra fil) in a Teflon mold with one semi-circular notch. Then, the samples were randomly divided into the following three subgroups based on the curing modes (high, low and soft) and were light-cured. The samples were removed from the molds, and their VHN and depth of cure were measured. Data were analyzed using One-way ANOVA and Tukey’s post hoc test at the significance level of P<0.05.

The mean VHN of the X-tra fil composite was significantly higher than that of Tetric N-Ceram composite (P<0.001). The depth of cure of X-tra fil composite was also significantly higher than that of Tetric N-Ceram composite in high and soft curing modes (P<0.001).

According to the current results, X-tra fil composite is a convenient material for the restoration of deep cavity in posterior teeth compared with Tetric N-Ceram.

Today, the use of all-ceramic restorations has increased due to their physical properties as well as translucency and esthetic appearance.The aim of this study was to compare the shear bond strength (SBS) between two methods of e-max ceramic cementing.

The study groups were 1 flowable composite as cement (FC group) and 2) choice2 cement (C2 group). The samples were fixed to a KOOPA universal testing machine for SBS testing. Tthe data were analyzed using SPSS 20 through T-test at significant level of P˂0.05.

The average SBS in the FC group was 10.41±2.17 and The average SBS in the C2 group was 13.28 ±1.52. There was a statistically significant difference between the SBS of both groups (p<0.001).

This study demonstrated  that ,the use of flowable composite instead of C2 cement is not not recommended for cementing e-max ceramics.

Hyperdontia is the increase in the number of teeth. Hereditary patterns have been suggested and many cases are multifactorial. Syndromes such as Cleidocranial dysplasia and Down syndrome are associated with hyperdontia and non-syndromic cases are very rare. The aim of this study was to report multiple supernumerary teeth in a non-syndromic patient. A 25-year-old female patient without any systemic, metabolic, or mental disorders has been referred to the Department of oral medicine, Isfahan school of dentistry for an oral examination. In the panoramic radiography, 12 impacted teeth were accidentally found. Four of them were impacted third molars and the rest were supernumerary teeth. The presence of supernumerary teeth causes situations such as eruption latency of permanent teeth and root resorption of adjacent teeth. In these cases, a complete clinical and radiographic examination of the patient with a detailed medical and dental history should be performed for the appropriate surgical and orthodontic treatment plan.