Dental Research Journal最新文献

Background: There is an increasing desire for teeth bleching after orthodontic treatment. Therefor, this study aims to evaluate the effect of carbamide peroxide 15% and thermocycling on the compressive strength of polyethylene terephthalate glycol (PETG) thermoplastic retainer material.

Materials and methods: In this in vitro study, forty samples of PETG material were thermoformed over a plastic template (10 mm × 8 mm × 2 mm). The samples were divided into four groups, with ten samples in each group. Group I served as the control, Group II was exposed to carbamide peroxide 15% (5 h daily for 14 days), Group III underwent thermocycling (5000 times), and Group IV underwent thermocycling (5000 times) followed by exposure to carbamide peroxide 15% (5 h daily for 14 days). The compressive strength of the groups was then evaluated using one-way ANOVA and Tukey's HSD tests for statistical analysis. The significance level was set to 0.05.

Results: The analysis showed a significant difference among the four groups. The compressive strength of all groups significantly decreased compared to the control group. Group II exhibited a significant decrease compared to Group III (P = 0.003). However, there was no significant difference between Group II and Group IV (P = 0.191). In addition, there was no significant difference observed between Group III and Group IV (P = 0.308). Group II had the lowest compressive strength (163.9 Mpa).

Conclusion: It is not recommended to use a thermoplastic retainer as a bleaching tray during the initial phase of retention. However, since there were no further harmful effects of bleaching agents observed after thermocycling, it is possible to recommend the use of a thermoplastic retainer as a bleaching tray toward the end of the retention phase.

Background: During tooth preparation, the clinician may face a hard remineralized enamel surrounding the cavity with unknown effects on the enamel bond strength. This study aims to assess the effect of remineralizing pretreatments with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) or CPP-amorphous calcium fluoride phosphate (CPP-ACFP) on the bond strength of composite resin and sound or demineralized enamel.

Materials and methods: This study employed an in vitro experimental factorial design. A total of 144 enamel surfaces were prepared and randomly divided into 12 groups (G1-G12). The surfaces of G7-12 were demineralized to create a lesion (L), while G1-6 were assigned to the sound (S) enamel group. The three pretreatment protocols were CPP-ACFP, CPP-ACP, or no pretreatment for a 10-day pH-cycling period. A composite rod was bonded to the surfaces using a self-etch or total-etch bonding system. Shear force was applied, and the bond strengths of the specimens were measured. The data were analyzed using the Kruskal-Wallis test, followed by pairwise comparisons using Dunn's test. The significance level for all tests was set at 0.05.

Results: The sound (S) groups (33.81 ± 8.48) showed a significantly higher bond strength than the lesion (L) groups (25.77 ± 6.69). Among the pretreatments, CPP-ACFP-pretreated groups had the highest bond strength (33.86 ± 8.87). Pairwise comparisons showed significant differences between CPP-ACFP-treated demineralized enamel and control demineralized enamel in both bonding systems (P = 0.019 and P = 0.025 for Clearfil SE and Optibond FL, respectively).

Conclusion: Pretreatment of demineralized enamel with CPP-ACFP before using total-etch and self-etch systems results in a bond strength comparable to that of sound enamel, making it clinically acceptable.

Background: Peri-implantitis is implant-associated inflammation that leads to irreversible loss of surrounding bone. Early diagnosis increases the success of peri-implantitis treatment. Despite various studies associated with this most common complication, early detection of the onset of peri-implantitis remains a major challenge. Molecular biomarkers are applicable detectors for the early detection of numerous diseases and monitoring their development. The present study aimed to predict interactome networks of up/down regulated proteins and analyze drug-gene interaction in peri-implantitis to identify the diagnostic and druggable genes.

Materials and methods: In this in silico study, a suitable gene expression profile related to peri-implantitis was retrieved from Gene Expression Omnibus. Screening differentially expressed genes (DEGs) was carried out based on the cut-off criteria |log2 (fold change)|>2 and P < 0.05. Interactome networks were constructed and analyzed by the STRING database (Version: 12.0) and the Cytoscape software (version: 3.9.1). Finally, to investigate drug-gene interaction, detected hub genes were analyzed by DGIdb (version: 5.0.6).

Results: A total of 216 genes were identified as DEGs (129 down-regulated and 87 up-regulated genes) in peri-implantitis. Regarding Cytoscape analysis, FCGR3B, CSF3R, AQP9, TREM1, and P2RY13 were the top 5 hub nodes of up-regulated DEGs, and CXCL10, OASL, IFIT1, RSAD2, and ISG15 were the top 5 hub nodes of down-regulated DEGs. Among these key nods, AQP9, CSF3R, CXCL10, IFIT1, ISG15, OASL, and, FCGR3B were therapeutic targets and had approved drugs.

Conclusion: In this research, seven genes have been identified as druggable genes in peri-implantitis which can be used to treat and diagnose this disease. However, these results and identified genes need to be validated by clinical or experimental methods.

Background: Ameloblastoma is a benign odontogenic neoplasm with a high recurrence rate. Identifying cellular and molecular changes in this neoplasm may help predict the recurrence risk. Bcl-2 and galectin-3 are anti-apoptotic proteins associated with the prognosis of many neoplasms. However, there are a few studies focusing on the association between these two markers and recurrence of ameloblastoma. This study aimed to investigate the association of Bcl-2 plus galectin-3 expression and recurrence of ameloblastoma.

Materials and methods: This retrospective cross-sectional study was designed on 48 paraffin-embedded blocks diagnosed as ameloblastoma from 1998 to 2019. We retrieved follow-up data from patients' records and used immunohistochemical staining for Bcl-2 and galectin-3 antibodies. Then, we analyzed their association with recurrence using Chi-square and Mann-Whitney test as well as recurrence-free survival using Kaplan-Meier curves and linear Cox regression. The level of statistical significance was P < 0.05.

Results: Twenty-six patients had experienced the recurrence. The mean follow-up time was 93.53 months. There was a significant association between Bcl-2 plus cytoplasmic galectin-3 staining and recurrence (both P < 0.001). Furthermore, in univariate analysis, high expression of Bcl-2 was associated with less recurrence-free survival (log-rank: P = 0.020-univariable Cox: P = 0.033), but in multiple Cox regression, there was no significant association (P = 0.471). High cytoplasmic galectin-3 expression was also associated with less recurrence-free survival (log-rank: P = 0.007-univariable Cox: P = 0.015-multiple Cox: P = 0.044). Furthermore, we found a correlation between Bcl-2 and cytoplasmic galectin-3 staining (P = 0.001).

Conclusion: It seems that Bcl-2 and cytoplasmic galectin-3 staining might predict the risk of ameloblastoma recurrence. However, only the cytoplasmic galectin-3 staining might be an independent predictor of ameloblastoma recurrence, and we recommend further studies.

Background: Head-and-neck radiotherapy can change oral Candida species and lead to the development of refractory oral candidiasis resistant to the commonly prescribed antifungal medications such as fluconazole. Atorvastatin exerts an antifungal effect by inhibiting the synthesis of fungal wall ergosterol and impairing mitochondrial function. This study aimed to compare the antifungal effects of fluconazole and atorvastatin on Candida species isolated from patients undergoing head-and-neck radiotherapy.

Materials and methods: In this clinical in vitro study, swab samples were collected from 33 patients admitted to Isfahan Seyed-O-Shohada Hospital before the onset and 2 weeks after the initiation of radiotherapy. The antifungal effects of fluconazole and atorvastatin were evaluated by the microdilution test according to the Clinical and Laboratory Standards Institute standards, and measuring their minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). Data were analyzed by the Mann-Whitney U-test and the statistical significance level was considered P < 0.05.

Results: The results showed that the MIC24, MIC48, and MFC of fluconazole were significantly lower than those of atorvastatin for Candida albicans, Candida tropicalis, and Candida glabrata both before (P < 0.001 for all) and during (P < 0.001 to P = 0.003) radiotherapy.

Conclusion: According to the results, fluconazole has antifungal effects comparable to those of atorvastatin, but in much lower doses. Atorvastatin showed optimal antifungal effects but in doses beyond the clinically applicable threshold.

Background: There is ample evidence showing the development of nystatin-resistant strains in patients undergoing malignancy treatment. Amphotericin B is a polyene antifungal drug that combines with ergosterol to cause cell death and is more effective on fungal species than routine antifungals such as nystatin. This study aimed to compare the effect of nystatin and amphotericin B on fungal species isolated from patients before and during head-and-neck radiotherapy.

Materials and methods: This in vitro experimental study was performed on samples isolated from patients undergoing head-and-neck radiotherapy before and during radiotherapy at Sayed al-Shohada Hospital in Isfahan, Iran. The isolates were identified by polymerase chain reaction-restriction fragment length polymorphism. Antifungal effects were determined by the microdilution method based on clinical and laboratory standards institute standards and minimum inhibitory concentration (MIC), minimum lethal concentration (MFC), drug sensitivity, and resistance were measured. The data were analyzed by SPSS version 22 (level of significance: 0.05).

Results: Before radiotherapy, all albicans strains were sensitive to nystatin, whereas 71.4% were sensitive to amphotericin B. After radiotherapy, Candida albicans strains were 100% sensitive to nystatin and 75% sensitive to amphotericin B.

Conclusion: The present study showed that before radiotherapy, all species isolated from patients, including C. albicans, C. tropicalis, and C. glabrata, were sensitive to nystatin, whereas a percentage of albicans species showed resistance to amphotericin B. In the 2^nd week of radiotherapy, the same as before radiotherapy, all species isolated from patients were sensitive to nystatin, whereas a percentage of albicans species showed resistance to amphotericin B. In general, the current study showed that before and after radiotherapy, the antifungal effect of nystatin is greater than amphotericin B.

Background: Chronic apical periodontitis (AP) may influence the outcome of root canal treatment. Thus, it is important to diagnose AP using the best method available. This research was done to compare the diagnostic accuracy of parallel periapical radiography (PR) and different field of views (FOVs) of cone-beam computed tomography (CBCT).

Materials and methods: This ex vivo study was done on six human mandibles. After extraction of the teeth, periapical lesions with different sizes were prepared randomly by drilling a hole at the base of the socket using a bur. From among 67 sockets, 21 sockets had no lesion (control); then, all mandibles were scanned by CBCT with different FOVs and paralleling periapical technique radiography. The images were assessed by two examiners. The quantitative data were analyzed by intraclass correlation coefficient (ICC) and the qualitative data were analyzed by McNemar's test (α = 0.05). Sensitivity, specificity, and accuracy were calculated. Inter-observer agreement was assessed using kappa statistics for qualitative data and ICC for quantitative data.

Results: The quantitative scores were compared with the gold standard using ICC, which showed maximum agreement for the dental FOV of CBCT (93.3) and minimum agreement for PR (62.5) (P < 0.001). For qualitative data, maximum agreement was found for the dental FOV of CBCT (97.1%), and minimum agreement was reported for PR (59.7%). Kappa values were variable between 0.271 and 0.924 (P < 0.001). Maximum sensitivity was found for the dental FOV of CBCT (96%) and minimum sensitivity was observed for PR (51%). The inter-observer agreement was 0.922 for qualitative data and 0.90 for quantitative data (P < 0.001). There were no significant differences between CBCT with different FOVs and defect sizes (gold standard) while we found significant differences for periapical by defect sizes.

Conclusion: CBCT with dental FOV presents the highest sensitivity and diagnostic accuracy for detection and characterization of simulated AP.

Background: This study compared the antibacterial effects of 940 nm diode laser and sodium hypochlorite and chlorhexidine irrigations on Enterococcus faecalis in human permanent single-rooted teeth.

Materials and methods: In this in vitro study, 65 extracted human single-rooted teeth were prepared using the crown-down method using rotary files. The root canals were irrigated with 5.25% sodium hypochlorite, 17% ethylenediaminetetraacetic acid, and normal saline solution. After placing the roots in microtubules, they were transferred into an autoclave. The teeth were randomly divided into four groups (n = 15): laser, sodium hypochlorite, chlorhexidine, and saline. Three teeth were assigned to the positive control group and two to the negative control group. The root canals were sampled, and the colony counts were determined 24 h later. Then, antibacterial agents were applied to the canals, and immediately after, the root canals were sampled, and the colony counts were determined 24 h later. The data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests using the SPSS software version 26. The significance level was defined at P < 0.05.

Results: The results showed that sodium hypochlorite, chlorhexidine, laser, and normal saline significantly reduced bacterial colony counts, confirming their antimicrobial effects (P < 0.001). Sodium hypochlorite and chlorhexidine showed the highest antimicrobial effects, with no significant differences between the sodium hypochlorite and chlorhexidine groups (P = 0.512); however, there were significant differences between the other groups (P < 0.001).

Conclusion: According to the results, 940 nm diode laser beams significantly reduced E. faecalis counts and could be used as a new, effective, and complementary treatment in disinfecting the root canal.

Background: Periapical extrusion of debris for root retreatment will effectively improve the posttreatment inflammation and pain. The aim of this study was to investigate the extruded debris for root retreatment using XP shaper and ProTaper files.

Materials and methods: In his experimental laboratory study, 40 extracted human maxillary molars were used in this laboratory study. After disinfection and equalization of length, the samples were treated with a passive step-back technique and dressed. The samples placed in the tubes for retreatment were divided into four groups: (1) XP shaper file and hypochlorite, (2) XP shaper file and ethylenediaminetetraacetic acid (EDTA), (3) ProTaper file and hypochlorite, and (4) ProTaper file and EDTA. Then, the teeth were taken out of the tubes, and cleaned to collect the remaining apical debris. The weight of the tube and the extruded debris was measured again. Data were analyzed using the Kruskal-Wallis test (α =0.05).

Results: The highest average of extruded debris was related to the XP shaper file with EDTA solution, and the lowest average was related to the ProTaper file with hypochlorite solution. Between the two files used with EDTA and hypochlorite solution, the average debris extrusion of the XP shaper file with EDTA solution was significantly higher (P < 0.05) compared to the ProTaper and XP shaper files with hypochlorite solution (P < 0.05).

Conclusion: Regardless of the type of irrigant material, the ProTaper file can be a more suitable option than the XP shaper file for retreatment of the tooth root canal with minimal debris extrusion.

Background: This systematic review and meta-analysis aimed to assess the efficacy of autologous platelet concentrate (APCs) in comparison with coronally-advanced flap alone or in combination with connective tissue graft or other biomaterials or bioactive agents for root coverage (RC) of Miller's Class I and II gingival recession defects by measuring the keratinized mucosa width (KMW).

Materials and methods: This systematic review and meta-analysis was conducted in accordance with the preferred reporting items for systematic reviews and meta-analysis guidelines. An electronic search of the literature was conducted in PubMed, EMBASE, Scopus, Cochrane, Web of Science, Magiran, Scientific Information Database, and Irandoc for randomized clinical trials (RCTs) that used APCs for RC in their intervention group. Eligible articles were retrieved by assessment of titles and abstracts and then the full texts. The risk of bias was assessed by the Cochrane Library Risk of Bias Assessment Tool. Meta-analysis was carried out by RevMan 5.3 software. In the case of homogeneity, variables were reported as weighted mean difference (WMD) with 95% confidence interval (CI) for each group.

Results: The search yielded 689 articles; out of which, 32 were eligible for study inclusion. Meta-analysis did not show any additional effect for RC and KMW with APCs. Clinical parameters were as follows: RC: WMD = -1.57 mm (95% CI: -2.49, -0.659; P = 0.001) and KMW: -0.106 mm (95% CI: -0.3222, 0.110; P = 0.337).

Conclusion: The application of APCs for RC of Miller's Class I and II gingival recession defects does not seem to improve the clinical parameters.