مجله دانشکده دندان پزشکی اصفهان
سال پانزدهم شماره 4 (پیاپی 69، زمستان 1398)

Currently, panoramic radiography is very popular with dentists due to its proper cost and low radiation dose in terms of the data it provides. During the diagnosis and treatment process, a dentist should keep himself and the patient safe from the dangerous effects of ionizing radiation during radiography. Therefore, this study was undertaken to present a guideline for dentists and technicians for better patient protection. Materials &

In this cross-sectional, descriptive/analytical study, 4 calibrated TLDs were placed in appropriate positions within a holder and placed on the surface of a lead apron on the anterior and posterior aspects. One TLD was also placed in the environment as a control. One hundred patients, candidates for taking panoramic radiographs, wore the lead apron and underwent conventional panoramic radiography. Then the TLDs were sent for processing and the results were analyzed with repeated-measurements ANOVA, post hoc least significant difference, one-sample t-test and paired-samples t-test (α = 0.01).

TLDs that had undergone radiographic exposure 100 times showed the absorbed dose in millisievert unit. Skin dose on the postero-superior region (0.31) was the highest amount measured, followed by the absorption dose on the postero-inferior region (0.28), antero-inferior region (0.22), antero-superior region (0.19); the control TLD which was placed outside the room showed insignificant absorption dose.

In this study, the patients’ radiation doses were separately reported for the anterior and posterior mid-body regions. The skin absorbed dose in the posterior mid-body region was higher in comparison with the anterior region. Therefore, it is advisable for the patients to wear the lead apron like a coat on the posterior region.

The aim of the present study was to determine the effect of three lasers, 980-nm diode, 810-nm diode and Er:YAG laser beams on temperature changes of titanium discs with SLA (sandblast large-grit acid etch) surface. Materials &

In this interventional in vitro study, 17 titanium discs with SLA surface, with a diameter of 5.2 mm and a height of 2 mm, were prepared. The specimens were divided into 3 groups (n = 5) and 1 control group (n = 2). The first group was irradiated by Er:YAG laser; the second and third groups were irradiated with 810-nm and 980-nm diode laser beams. No intervention was implemented in the fourth group. Temperature was measured before and after intervention (laser irradiation) with a digital thermometer. Data were analyzed with one-way ANOVA, followed by post hoc Tukey tests, using SPSS 22 (α < 0.05).

The results showed significant differences in ∆T between the 4 groups (p value < 0.05). The minimum temperature changes compared to the control group were recorded in the group irradiated with Er:YAG laser beams and the maximum temperature changes compared to the control group were recorded in the group irradiated with 980-nm diode laser beams.

Considering the decrease in temperature on the surface of the titanium discs with the use of Er:YAG laser beams, this laser is recommended for disinfection of implant surfaces; 810-nm diode laser proved more effective because of the lower temperature rise.

Use of the CBCT technique to determine root morphology minimizes the rate of treatment failure and adverse effects, such as gouging and perforations. The aim of this study was to evaluate the prevalence of third roots and canals in maxillary premolars using the CBCT technique. Materials &

This descriptive/analytical study was performed on 120 CBCT images of patients referring to the Radiology Department of Azad University of Isfahan. Demographic characteristics of patients (age, sex and jaw side) and the number of roots and canals were studied and recorded. Data were analyzed with Wilcoxon and Mann-Whitney U tests using SPSS 20 (α = 0.05).

In maxillary first premolar teeth, 31.7% of the teeth were single-rooted, 67.1% were two-rooted and 3.1% were three-rooted. In the second maxillary premolars, 94.2% had one root and 5.8% had two roots. In the first maxillary premolar teeth, 9.2% had one root canal, 95.2% had two root canals and 1.7% had three root canals. In the second maxillary premolar teeth, 74.6% had one root canal, 25% had two root canals and 0.4% had three root canals. There were no significant differences between the number of root canals and roots in maxillary first and second premolar teeth between the left and right sides (p value > 0.05). There were no significant differences between the number of root canals and roots in the first and second premolar teeth between the left and right sides and between the male and female subjects (p value > 0.05). The number of roots and canals of maxillary second premolar teeth on both the left and right sides was significantly higher in men than in women (p value < 0.05).

Three roots and three canals are very rare in the maxillary first and second premolars. However, it is necessary for each dentist to be aware of the possibility of excess roots and root canals in maxillary first and second premolars.

Alterations in mandibular condyle morphology is one of the common problems in different age groups. These variations of the condylar are mostly progressive due to the initial changes in remodeling. Therefore, alterations in the size and shape of the condylar bone are of particular importance in the diagnosis of temporomandibular joint-related diseases. This study aimed to determine the radiographic changes in mandibular condyles and its related factors.

This historical cohort research was carried out on 99 patients in the Faculty of Dentistry, Islamic Azad University, Tehran, in 2016. In this study, the temporomandibular disorders (TMDs), age and Eichner's model were evaluated. Mandibular condyle changes were evaluated using panoramic radiography. Data were analyzed with chi-squared test and Pearson’s correlation coefficient, using SPSS 22 (α = 0.05).

In this study, of 99 cases of radiographic examination in three different age groups, 71 cases (71.7%) of condyle deformity were detected. Ely's cyst was the most commonly seen condylar radiographic change, and 50.5% of the subjects had at least one affected condyle, followed by flat condyle (49.5%), erosion (16.2%) and osteophyte (10.1%) in descending order. Sclerosis (1%), condylar convexity (3%) and condylar concavity (2%) were relatively rare.

Based on the results, condylar changes did not increase with age. Statistically, TMD was not responsible for condylar deformity. The Eichner's pattern C (without occlusal contacts on the remaining teeth) was found to be the most frequent in subjects aged 60-70 years. This indicates that the occlusal forces in the elderly was very low and weak, and the occlusion and edentulism did not have a direct relationship with the condyle deformity.

Debonding of ceramic brackets results in enamel damage and bracket fracture due to a strong bond of ceramic brackets and low fracture resistance. The aim of this study was to compare enamel damage upon debonding of ceramic brackets with and without CO2 laser in orthodontic treatment. Materials &

In this experimental study, 44 extracted first premolar teeth were selected and randomly divided into two groups (n = 22). After bonding, the teeth were divided into two group with and without the use of CO2 laser for debonding of brackets. A stereomicroscope was used at ×10 to determine the exact number and length of enamel cracks before and after debonding of the brackets. Data were analyzed with paired t-test and t-test using SPSS 23 (α = 0.05).

In the group without laser, the rate of enamel fracture was 4.5% and in 9.1% of the cases there were fractures in the bracket base. There were no fractures or cracks in the enamel or bracket bases. In this group, the mean length of cracks was significantly low (p value < 0.001). There were significant differences in the lengths of the cracks in both groups before and after debonding (p value < 0.018). Although the number of cracks in the enamel in both groups increased after debonding, this increase was not significant in the laser group (p value < 0.001).

Debonding of ceramic brackets with CO2 laser resulted in a decrease in enamel damage during debonding.

Some studies have shown that loss of teeth and conventional complete dentures have a negative effect on oral health-related quality of life of patients; some other studies have reported high satisfaction with daily life in these patients. Since the results of studies in this regard are contradictory and on the other hand, in Iran only few studies have evaluated this issue, in this study, the quality of life of denture-treated patients was studied in Hamadan Dental School in 2016-2018. Materials &

The participants of this study were selected from patients referring to Hamadan Dental School in 2016-2018. Demographic and clinical data were recorded, and oral health-related quality of life was evaluated by the OHIP-14 standard questionnaire before denture delivery and one month after denture delivery and compared. Data were analyzed with SPSS 21, using descriptive statistics and statistical tests such as t-test, paired t-test, one-way ANOVA and Wilcoxon sign-test (α = 0.05).

The OHIP scores decreased significantly after the delivery of dentures in the all participants (p value = 0.008). This decrease was significant in women, but not significant in men.

In general, the use of complete dentures improved the oral health-related quality of life in the subjects. This improvement is related to aspects such as pronunciation, diet and embarrassment due to the general appearance.

Considering the effect of dental hygiene in people’s general health and since facilitation of community members’ visits to dental offices results in the improvement and enhancement of the indexes of this health field, the present study was undertaken to evaluate the relationship between anxiety sensitivity, sensory processing, brain-behavioral systems and alexithymia and anxiety in dental patients. Materials &

This analytical study was carried out using non-random sampling technique by including 383 male and female subjects referring to dental clinics in Esfahan in 2018. Research tools consisted of anxiety sensitivity questionnaire, questionnaire on highly sensitive subjects, inhibition scale/behavioral activation, alexithymia questionnaire and dental anxiety questionnaire. Data were analyzed with SPSS 22, using correlation test and multiple regression analysis.

The results showed that 28.4% of changes in dental anxiety can be explained with anxiety sensitivity, sensory processing sensitivity and alexithymia. In addition, 26.1% of changes in dental anxiety can be explained with two dimensions of anxiety sensitivities (fear of body concerns and fear of lack of cognitive control); and 17.3% of changes in this variable can be explained with different aspects of sensory processing sensitivity (ease of excitement, low sensory threshold and aesthetic sensitivity) (p value < 0.05).

There were significant relationships between the three variables of anxiety sensitivity, sensory processing sensitivity and alexithymia and dental anxiety of all the four predictors of the study; however, there was no significant relationship between brain-behavioral systems and dental anxiety.

Although medical emergencies are not common in dental offices, lack of appropriate attention to such incidents might result in irreparable complications in patients. The aim of this study was to evaluate the knowledge and attitude of general dentists in Isfahan in dealing with common medical emergencies.

A total of 120 general dentists (53 males and 67 females, with a mean age of 41.2 ± 13 years) working in Isfahan were randomly selected for the purpose of this questionnaire-based cross-sectional study. The questionnaire included demographic variables, data on education history, and dentists’ attitude toward the need for more education and a test with 10 questions on how to deal with common medical emergencies. Data were analyzed with Pearson’s and Spearman’s tests, independent t-test, chi-squared test and Fischer’s exact test using SPSS 22 (α = 0.05).

A total of 69 dentists (57.5%) acquired poor scores (0-5), 32 acquired a moderate score (6), 13 acquired a good score (7) and 6 acquired very good scores (≥ 8); 94% of the participants stated that they had not received adequate education in this field, and nearly 97% emphasized on the need for more education. There was no significant difference in the overall mean scores between male and female subjects (p value = 0.38). Knowledge level increased with years since graduation (p value = 0.028). Finally, <30% of the dentists stated that they had all the equipment and essential medicine to manage medical emergencies in their office.

Dentists in Isfahan exhibited low knowledge level about proper management of common medical emergencies and were not properly trained for such situations and their offices were not well equipped. This study showed that these dentists believe they need training in this field and past education has not met their needs.

Provision of proper bond strength for tooth-colored restorations is very important in the restoration of primary teeth. The aim of this study was to compare shear bond strengths of Clearfil SE two-step self-etch, Palfique one-step self-etch and G-Premio universal bonding agents. Materials &

A total of 45 intact extracted primary canine teeth were collected for the purpose of this in vitro study and randomly divided into three groups (n = 15). The buccal surfaces of the teeth were prepared with 600-grit silicon carbide discs. The adhesive was applied by a micro-brush to the surface of the teeth according to manufacturer’s instructions; Z350XT composite resin was placed using a plastic mold measuring 2 mm in diameter and 2.5 mm in length and then light-cured. Finally, the shear bond strength was measured using a universal testing machine. Data were analyzed with ANOVA and Tukey test, using SPSS 21 (α = 0.05).

The highest shear bond strength was recorded in G-Premio bond with a mean of 20.60 MPa. Clearfil SE Bond ranked the second with a mean of 18.62 MPa. Palfique Bond exhibited the lowest bond strength (14.64 MPa). There was a significant difference between G-Premio Bond and Palfique Bond (p value < 0.001) and between SE Bond and Palfique Bond (p value = 0.01). However, there was no significant difference between G-Premio Bond and SE Bond (p value = 0.29).

Since 17 MPa has been proposed as the critical value needed to withstand polymerization shrinkage, both G-Premio Bond and Clear fil SE Bond have adequate strength for use in primary teeth. Palfique Bond exhibited lower bond strength compared to the two other bonding agents inn primary teeth. Due to the fewer steps of G-Premio Bond in the self-etch mode, use of this bonding agent appears to be logical for the restoration of primary teeth.

Fear and anxiety of dental treatment in children could cause behavioral changes. In addition, dental pain and discomfort could lead to behavioral disorders in children. Treatments under general anesthesia might decrease behavioral disorders due to an improvement in the child’s medical condition. The aim of this study was to determine and compare the mean scores of fear and anxiety based on the standard behavioral change questionnaire before and after dental treatment under general anesthesia. Materials &

This descriptive cross-sectional study evaluated children who underwent dental treatment under general anesthesia. Seventy-eight behavioral change questionnaires, consisting of 22 items, were distributed among the children’s mothers. The questionnaires were completed once just before general anesthesia and once a month after general anesthesia by the mothers in order to obtain the mean score of behavioral changes. Data were analyzed with t-test, one-way ANOVA and paired ttest (α = 0.05).

Based on statistical data, in all the cases the scores of behavioral problems after general anesthesia were better than those before general anesthesia. In addition, there was a significant relation between the number of the dental procedures and the mean score of behavioral changes, indicating an improvement in behavior with an increase in the number of dental procedures.

Implementation of all the dental procedures for children under general anesthesia improves their behavioral conditions, presumably due to an improvement in their dental condition.

Gum chewing is one of oral parafunctional habits and is considered as an etiologic factor for temporomandibular joint disorders. The aim of this study was to evaluate the relation between type, duration and pattern of gum chewing and TMD signs and symptoms. Materials &

In this descriptive‒ analytical study, 73 subjects aged 20-30 years, who were gum chewers, were evaluated by considering inclusion and exclusion criteria and ethical codes. Type, frequency and chewing patterns were evaluated by a questionnaire and signs and symptoms of TMD through clinical examinations and the data were recorded. Data analysis was carried out with SPSS 20, using chi-squared, MannWhitney and Fisher’s exact tests (p value ≤ 0.05).

In this study, the most common sign of TMD was joint clicks (31.5%). Jaw movement limitation was more prevalent in females (p value = 0.018). Type, history and duration of chewing gum consumption were not significantly related with signs and symptoms of TMD. Significant relationships were observed between the rate of gum chewing cycle (p value = 0.04), continuity of initial chewing cycle (p value = 0.048), time of change in chewing cycle (p value = 0.04) and some signs and symptoms of TMD.

No significant relationship was found between the signs and symptoms of TMD and type and time of gum chewing; however, there were significant relations between the pattern of gum chewing, rate of gum chewing cycle and time of change in chewing cycle and the TMD signs and symptoms.

Since the harmony and the balance of the face are the result of the interaction between the hard tissue and soft tissues, it is essential to understand the relationship between these two tissues in the treatment planning. The aim of the present study was to investigate the facial angles and face convex angle in the soft tissue and its association with hard tissues in patients referred to Bandar Abbas Faculty of Dentistry. Materials &

In this cross-sectional study 75 lateral cephalograms were evaluated. The subjects were 18-25 years of age and all had a complete permanent dentition (except for the third molars) without a history of facial traumas, orthognathic surgery, orthodontic treatment and congenital anomalies. Facial angle and facial convexity angle of hard and soft tissues, chin soft tissue thickness and upper lip thickness were determined. Data were analyzed with SPSS 22, Mann-Whitney test was used for comparison of male and female subjects. Pearson’s correlation coefficient was used for the analysis of correlations (p value < 0.05).

There was a significant correlation between soft tissue facial angle and hard tissue facial angle (r = 0.9, p value < 0.05) and between soft tissue facial convexity and hard tissue convexity angle (r = 0.7, p value < 0.05). The mean lip thicknesses in male and female subjects were 14.58 ± 2.33 and 12.20 ± 1.74 mm, respectively. There was a significant correlation between chin soft tissue thickness and gender (p value < 0.05). The mean thickness of chin soft tissue in males (12.50 ± 2.32) was higher than that in females (10.84 ± 2.32).

Since there was a significant correlation between soft tissue facial angle and convexity and soft tissue facial angle and convexity, we can use soft tissues to gain knowledge about hard tissues.