Dental Research Journal最新文献

Background: Odontogenic keratocyst (OKC) is one of the common odontogenic cysts with aggressive clinical behavior and a high recurrence rate. Epithelial-mesenchymal transition (EMT) is a process, in which the epithelial cell loses its epithelial characteristics and acquires mesenchymal features. Since the evidence for the involvement of EMT in the development of OKC is still limited, the present study aimed to investigate the immunohistochemical expression of EMT-related proteins (E-cadherin and N-cadherin) in OKC and compare them to radicular cyst (RC) and dentigerous cyst (DC).

Materials and methods: In this descriptive analytical study, 75 paraffin blocks, including 25 DCs, 25 OKC, and 25 RCs, were selected. Immunohistochemical staining was performed to determine the expression and staining intensity of E-cadherin and N-cadherin proteins. The specimens were examined under an optical microscope, and the data were analyzed using the Kruskal-Wallis test in SPSS statistical software (version 23) with a significance level of 5%.

Results: The expression of N-cadherin in OKC was higher than that in other cysts; nonetheless, there was no statistically significant difference (P = 0.331). The staining intensity of N-cadherin was weak in most cases, and this difference was not statistically significant (P = 0.252). E-cadherin expression in OKC was significantly lower than that in radicular and DCs (P = 0.003). In addition, the staining intensity of E-cadherin in OKC was weak and moderate (P = 0.003).

Conclusion: In this study, we observed an increase in the expression of N-cadherin in OKC. In addition, the protein expression levels of E-cadherin in OKC were significantly lower compared to DC and RC. Therefore, it appears that the EMT process likely occurs in OKC and may contribute to its local aggressive behavior.

Background: Over the past 5 years, the use of immune checkpoint inhibitors in the treatment of head-and-neck squamous cell carcinoma (HNSCC) has increased. Both programmed death-ligand 1 (PD-L1) and cluster of differentiation 68 (CD68) are overexpressed in various carcinomas. Consequently, evaluating the expression of CD68 and PD-L1 in HNSCC lesions may lead to detecting a possible marker for HNSCC. This study aimed to evaluate the expression of PDL1 and CD68 markers in a patient with oral squamous cell carcinoma (OSCC) and examine its relationship with depth of invasion (DOI) and immunofluorescence (IF) through immunohistochemistry.

Materials and methods: This cross-sectional study was conducted in the School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran, Department of Oral and Maxillofacial Pathology. Thirty-four paraffin blocks and demographic information of 15 female and 19 male OSCC patients were collected. Following sample preparations, immunohistochemical staining was performed. Subsequently, each tissue section was analyzed for tumor-infiltrating lymphocytes by CD68 marker and PD-L1 expression. Data analysis was conducted using SPSS software (version 25). Chi-square, Shapiro-Wilk, and independent t-analytical tests were employed for statistical assessments. P < 0.05 was remarked as statistically significant.

Results: CD68 and PDL1 expression in the squamous cell carcinoma (SCC) group was higher than the control group (P < 0.001). There was an increasing expression of PDL1 and CD68 as the grade of the disease progressed (P < 0.001 for each), as well as an increasing expression of IF and DOI.

Conclusion: The expression levels of CD68 and PDL1 were elevated in SCC tissues in comparison to the unaffected, healthy parts of the tissue section.

Background: The etiologies of childhood dental fear/dental behavior management problems have been extensively studied, especially the role of children's temperaments. This study aimed to evaluate the effect of temperament and its associated variables on the anxiety and cooperation level of preschool children in a dental clinic.

Materials and methods: This cross-sectional study involved 103, 4-6-year-old patients (39 boys and 64 girls). The children's parents or guardians completed the Child Fear Survey Schedule (CFSS) Dental Subscale and the Malhotra temperament questionnaire before the treatment. Patients' anxiety and cooperation levels were then assessed through three distinct treatment stages of fluoride therapy, injection of local anesthesia, and drilling, by applying the Venham anxiety and clinical cooperation scales. The data were analyzed using analysis of variance, Mann-Whitney, Kruskal-Wallis, and Chi-square tests. The significance level of 0.05 was deemed relevant in the analysis.

Results: A significant correlation was established between the mean of CFSS and the variety of temperament (P = 0.001). Anxiety and uncooperative behavior during injection and drilling were strongly related to lower sociability scores. Furthermore, higher anxiety during the drilling stage was related to higher impulsivity scores.

Conclusion: The evaluation of children's anxiety and cooperation in dental clinics heavily relies on temperament and certain related factors, such as sociability. These variables serve as crucial benchmarks in understanding and assessing the psychological state of children during dental procedures.

Background: This study aimed to measure light transmittance (LT) through various thicknesses of computer-aided design/computer-aided manufacturing bleach shade ceramics and to assess the Vickers microhardness (VMH) of underlying light-cured resin cement.

Materials and methods: In this in vitro study, a total of 90 ceramic discs (VITA Mark II [VM], VITA Suprinity, and CELTRA Duo) were prepared in 0.5, 1, and 1.5 mm thicknesses. To measure LT, the Valo light-curing unit was placed in direct contact with the ceramics on the radiometer. The average LT was recorded after three measurements. In addition, 90 specimens of light-cured resin cement (Allcem Veneer) were cured in Teflon molds (0.5 mm in depth) beneath ceramic pieces. Ten specimens of resin cement were also cured without the presence of ceramic as a control group. VMH of the cement specimens was reported. The data were analyzed by one-way analysis of variance and multiple comparison tests (α =0.05) in SPSS version 17.

Results: In each ceramic group, LT was negatively related to ceramic thickness (P < 0.05). At a thickness of 1.5 mm among all ceramic types, the VMH of resin cement was significantly decreased (P < 0.05). In all thicknesses, the VMH of resin cement was lower significantly than the control group, except for the thickness of 0.5 mm of VM.

Conclusion: According to the results of this study, light-cured cement is not a suitable option for cementing the studied bleach shade ceramics. Furthermore, the thickness of the ceramic has a significant effect on LT (P < 0.05), unlike VMH.

Background: Tooth bleaching sensitivity (TBS) after bleaching procedures is a common problem. This study was undertaken to determine the effect of preoperative systemic capsaicin on tooth sensitivity (TS) after in-office bleaching procedures.

Materials and methods: Thirty participants received the treatment in this clinical trial. The subjects were randomly assigned to two groups (n = 15). Placebo and 0.25% capsaicin were administered three times daily for 24 h, with the first dose being administrated 1 h before the bleaching procedure. The subjects underwent two bleaching sessions at a 2-week interval by applying 40% hydrogen peroxide gel on six upper anterior teeth. A visual analog scale (VAS) was used to evaluate TS. Data were analyzed with SPSS 24. Statistical analyses were carried out with the Wilcoxon test and paired t-test. Statistical significance was set at P ≤ 0.05.

Results: In the capsaicin group, there was a significant increase in TBS between the immediate and 1-h postoperative intervals and a significant decrease between 1- and 24-h postoperative intervals (P = 0.01 and P = 0.000, respectively). In the placebo group, there was a significant decrease between immediate and 24-h and between 1- and 24-h postoperative intervals (P = 0.007, P = 0.02). Milder TS was detected in the placebo group 24 h after bleaching (P < 0.05).

Conclusion: Under the limitations of this study, preoperative use of systemic capsaicin did not significantly affect TS after the in-office bleaching procedure.

Background: Gingival enlargement (GE) is a common clinical observation among orthodontic patients, yet its underlying causes remain unclear. This study aims to investigate the potential involvement of salivary matrix metalloproteinase (MMP)-2 and MMP-9 activity in orthodontic-induced GE.

Materials and methods: In this case-control study, we enrolled 50 subjects, including 25 individuals with GE and 25 without. The participants, aged 10-35 years, were in the 4^th or 5^th month of their orthodontic treatment. Comprehensive clinical assessments, encompassing plaque index, gingival index, and GE score were performed, and saliva samples were subjected to gelatin zymography to assess enzyme activity. Statistical analysis, including the Chi-square test for age distribution, independent samples t-test for age comparison between study groups, Mann-Whitney U test for MMP activity comparison, and Wilcoxon signed-rank test for comparison of data from the 4^th to 5^th months of treatment, was performed using SPSS version 23.0, with a significance level set at 0.05.

Results: MMP-2 activity was undetectable in the zymograms. In the 4^th month of treatment, MMP-9 activity was more prominent in the case group, though this disparity did not reach statistical significance in the 5^th month. Furthermore, MMP-9 activity did not exhibit a correlation with the GE score.

Conclusion: The activity of MMP-9 in the saliva of orthodontic patients with GE increases during the 4^th month of treatment, but no correlation exists with the degree of GE.

Background: The main disadvantage of silver diamine fluoride (SDF) is its persistent dark coloring. The aim of this study was to cover this discoloration on affected primary tooth dentin with different materials and subsequently measure their shear bond strength (SBS).

Materials and methods: In this in vitro study total of 60 primary teeth were demineralized and randomly divided into five groups (n = 12). The tooth surfaces were treated with 38% SDF, and restorative cylinders were built on the dentin as follows: (1) phosphoric acid etching + GLUMA Universal Adhesive (GUA; etch-and-rinse mode) + composite resin (CR); (2) GUA (self-etch mode) + CR; (3) resin-modified glass ionomer (RMGI; Fuji II); (4) Surefil One (self-adhesive CR); and (5) TheraCem (self-adhesive resin cement) + CR. After restoration, the specimens were tested for SBS. Failure mode was determined by digital analysis and scanning electron microscopy. Data were analyzed by one-way analysis of variance and Tukey's honest significant difference post hoc test. P <0.05 indicated statistical significance.

Results: Group 1 had significantly higher mean SBS (P < 0.05) compared to Groups 2-5, while Group 5 had the least SBS (P < 0.001). Mean SBS differences between Groups 2 and 3 were not significant (P = 0.328). Group 4 had lower mean SBS than Groups 1 (P < 0.001) and 2 (P = 0.17). Most groups showed adhesive failure.

Conclusion: CR associated with the universal adhesive in etch-and-rinse mode had much higher SBS than the other groups; therefore, we recommend it to cover the dark discoloration generated by SDF.

Background: Optimal dimensional stability is required for successful root canal treatment. A sealant called EndoSeal mineral trioxide aggregate (MTA) was recently introduced to the market due to its favorable physical and chemical properties. On the other hand, AH Plus (AHP) is considered the gold-standard seal.

Materials and methods: In this ex vivo quasi-experimental study, 24 single-canal premolars extracted from humans were cleaned and shaped with a motorized and rotary file, then that is divided into two groups. The teeth of each group were filled with gutta F3 and each type of sealant. The teeth were scanned by a micro-computed tomography device after 24 h. After 7 days of storage in phosphate-buffered saline solution, the samples were re-scanned. Data were analyzed using SPSS software (version 21). Descriptive data were presented as frequency, percentage, mean, and standard deviation. The Shapiro-Wilk and Kolmogorov-Smirnov tests were used to investigate the normality of the data. The Mann-Whitney test was used to compare the two groups, and the differences were ultimately not significant. The level of significance was set at 0.05 (P < 0.05).

Results: The mean differences between sealer volumes before and after the intervention were not significantly different between the two groups indicating that the EndoSeal MTA sealer is not inferior to the gold-standard root canal sealer, AHP.

Conclusion: EndoSeal MTA can be considered a reliable sealer in endodontic treatments and be subjected to further investigation.

Background: Various methods, including the use of probiotics, have been suggested to prevent caries. Caries, which is mainly caused by Streptococcus mutans, is one of the bacterial diseases that imposes a heavy cost on society. The present study was conducted to investigate the probiotic products available in Iranian pharmacies that are used for caries prevention.

Materials and methods: In this double-blind randomized clinical trial, 40 students of medicine and pharmacy were randomly allocated to two equal groups of intervention and control using random allocation software. The intervention group used a probiotic pill containing Streptococcus salivarius M18 and K12 bacteria every night before going to bed. The control group used a mouth freshener tablet with the same flavor as the probiotic tablet every night before going to bed. The data were analyzed by SPSS (version 24) software using descriptive statistics (central tendency and dispersion) and inferential statistics (paired t-test and independent t-test). Data were collected using Excel software, and statistical analyses were performed by SPSS software (version 24).

Results: The mean number of S. mutans in the intervention group was 754.5 cfu/mm before the intervention and 1701.5 cfu/mm after the intervention, which showed a statistically significant difference (P < 0.05). In the control group, the mean S. mutans was 683 cfu/mm at the beginning of the intervention and 659 cfu/mm at the end of the intervention, which did not indicate a statistically significant difference (P > 0.05). Moreover, the normality of data was checked by the Kolmogorov-Smirnov test.

Conclusion: The mean number of S. mutans bacteria in the group using probiotic tablets was significantly increased compared to those of the control group. However, further studies are suggested to evaluate these products.