Introduction: This study aimed to assess the fracture strength of endodontically treated mandibular molars with traditional endodontic access cavity (TEC) and truss endodontic access cavity (TREC) designs that were restored with composite resin and underwent thermocycling. Methods: Sixty mandibular first and second molars were randomly divided into 6 groups (n=10) of intact controls without thermocycling (group 1), intact controls with thermocycling (group 2), TEC without thermocycling (group 3), TEC with thermocycling (TEC-TC, group 4), TREC without thermocycling (group 5) and TREC with thermocycling (TREC-TC, group 6). The root canals were then instrumented to #25,7% using nickel-titanium files and were filled with gutta-percha and AH26 sealer with lateral compaction technique. Access cavity was restored with Gradia composite. All teeth were then thermocycled for 480 cycles between 5°C and 55°C for 30 seconds and their fracture strength was measured in a universal testing machine with a round-end piston with 6 mm diameter at a speed of 1 mm/min. Data were analyzed using two-way and one-way ANOVA. Results: Without thermocycling, the fracture strength of endodontically treated teeth with TREC designs had no significant difference with the control group (P> 0.05). However, both TEC and TREC designs significantly decreased the fracture strength of endodontically treated teeth after thermocycling (P< 0.05), such that minimum fracture strength was noted in TEC-TC group. Conclusion: Under the conditions of this ex vivo study, TREC enhances the fracture strength of endodontically treated teeth under thermal stresses.

This in vitro study assessed and compared the cytotoxicity of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, Biodentine (BD) and octacalcium phosphate (OCP) on stem cells of the human apical papilla (SCAP). SCAPs were isolated from two semi-impacted third molars. The cells were cultured in wells of an insert 24-well plate and were then incubated. The plates were then removed from the incubator and randomly divided into four experimental groups that were exposed to 1-mm discs of set MTA, CEM, BD or OCP, and one untreated control group. After 24, 48 and 168 h, the plates were removed from the incubator and 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) solution was added to each well. Data were analyzed at different time points using the repeated measures ANOVA followed by Bonferroni test and the level of significance was set at 0.05. Cytotoxicity of the four materials was not significantly different from that of the control group at 24, 48 and 168 h (P>0.05). Two-by-two comparison revealed that cytotoxicity of MTA and CEM cement was significantly different from each other at 168 h (P<0.05) although the cytotoxicity of CEM was less than MTA. Cytotoxicity of OCP and MTA was also significantly different from each other at 48 h and OCP had more favorable biocompatibility than MTA (P<0.05). CEM, OCP, BD and MTA showed acceptable biocompatibility when exposed to SCAP. Over time, CEM showed the least cytotoxicity among the materials under study.

Introduction: Clinical applications of bioactive materials are increasing in biomedical tissue engineering. This study sought to assess the effect of calcium enriched mixture (CEM) cement, Biodentine, mineral trioxide aggregate (MTA), octacalcium phosphate (OCP), and Atlantik on proliferation, odontogenic/osteogenic differentiation, and pro-inflammatory cytokine production by human stem cells of the apical papilla (SCAPs). Materials and methods: Proliferation of SCAPs treated with different biomaterials was evaluated using trypan blue exclusion test and flow cytometry. Differentiation of cells was evaluated using ALP activity, alizarin red staining, and RT-PCR. The expression of genes of pro-inflammatory cytokines was also evaluated using RT-PCR. Results: The SCAPs treated with biomaterials showed significantly higher proliferation, increased ALP activity, higher number of calcified nodules, and up-regulation of genes related to odontogenic/osteogenic markers compared to the control group. The expression of pro-inflammatory cytokines increased in all groups compared to the control group. Conclusion: The tested biomaterials could induce odontogenic/osteogenic differentiation in SCAPs. MTA had a greater potential for induction of differentiation of SCAPs to odontoblast-like cells while OCP had higher potential to induce differentiation of SCAPs to osteoblast-like cells (MTA↔ BD↔ CEM↔ Atlantik↔ OCP).

The Ras/RAF/MEK/ERK1/2 pathway is important in the control of growth signals, differentiation and cell survival. Over-expression and activation of this pathway have been reported in different types of cancer. This study analyses the promoter methylation and RNA expression profiles of ERK and RAF1 genes with risk of oral squamous cell carcinoma (OSCC) along with the promoter methylation status of ERK and RAF1 genes using a methylation-specific polymerase chain reaction (MS-PCR) in 86 paraffin-wax embedded samples of OSCC and 68 normal control tissues. Furthermore, ERK and RAF1 expression was analysed in 19 cases and 20 normal samples by real-time reverse transcription PCR. Frequency of promoter methylation was detected for ERK (93.02% and 6.98%) and RAF1 (95.35% and 4.65%) genes in cases and controls, respectively. Messenger RNA (mRNA) expression analysis indicated statistically significant difference between cases and controls for ERK (P<0.002) and RAF1 (P<0.006). The authors believe that this is the first report to show that expression of ERK and RAF1 is involved in risk of OSCC.

Background: Apoptosis is an important mechanism that is responsible for the physiological deletion of harmful, damaged, or unwanted cells. Changed expression of apoptosis-related genes may lead to abnormal cell proliferation and finally to tumorigenesis. Our aims were to analyze the promoter methylation and gene expression profiles of FADD and FAS genes in risk of OSCC. Material and Methods: we analyze the promoter methylation status of FADD and FAS genes using Methylation Specific PCR (MSP) in 86 OSCC tissues were kept in paraffin and 68 normal oral tissues applied as control. Also, FADD and FAS genes expression were analyzed in 19 cases and 20 normal specimens by Real-Time Reverse-Transcripts PCR. Results: Aberrant promoter methylation of FADD and FAS genes were detected in 12.79 % (11 of 86) and 60.46 % (52 of 86) of the OSCC cases, respectively, with a significant difference between cases and healthy controls for both FADD and FAS genes (P<0.001). The gene expression analysis showed statistically significant difference between cases and healthy controls for both FADD (p<0.02) and FAS (p<0.007) genes. Conclusions: To the best our knowledge, the data of this study are the first report regarding, the effect of promoter hypermethylation of the FADD and FAS genes in development of OSCC. To confirm the data, it is recommended doing further study in large sample sizes in various genetic populations.

Background/Purpose. In terms of the detection of tooth diagnosis, no intelligent detection has been done up till now. Dentists just look at images and then they can detect the diagnosis position in tooth based on their experiences. Using new technologies, scientists will implement detection and repair of tooth diagnosis intelligently. In this paper, we have introduced one intelligent method for detection using particle swarm optimization (PSO) and our mathematical formulation. This method was applied to 2D special images. Using developing of our method, we can detect tooth diagnosis for all of 2D and 3D images. Materials and Methods. In recent years, it is possible to implement intelligent processing of images by high efficiency optimization algorithms in many applications especially for detection of dental caries and restoration without human intervention. In the present work, we explain PSO algorithm with our detection formula for detection of dental caries and restoration. Also image processing helped us to implement our method. And to do so, pictures taken by digital radiography systems of tooth are used. Results and Conclusion. We implement some mathematics formula for fitness of PSO. Our results show that this method can detect dental caries and restoration in digital radiography pictures with the good convergence. In fact, the error rate of this method was 8%, so that it can be implemented for detection of dental caries and restoration. Using some parameters, it is possible that the error rate can be even reduced below 0.5%. Background/Purpose. In terms of the detection of tooth diagnosis, no intelligent detection has been done up till now. Dentists just look at images and then they can detect the diagnosis position in tooth based on their experiences. Using new technologies, scientists will implement detection and repair of tooth diagnosis intelligently. In this paper, we have introduced one intelligent method for detection using particle swarm optimization (PSO) and our mathematical formulation. This method was applied to 2D special images. Using developing of our method, we can detect tooth diagnosis for all of 2D and 3D images. Materials and Methods. In recent years, it is possible to implement intelligent processing of images by high efficiency optimization algorithms in many applications especially for detection of dental caries and restoration without human intervention. In the present work, we explain PSO algorithm with our detection formula for detection of dental caries and restoration. Also image processing helped us to implement our method. And to do so, pictures taken by digital radiography systems of tooth are used. Results and Conclusion. We implement some mathematics formula for fitness of PSO. Our results show that this method can detect dental caries and restoration in digital radiography pictures with the good convergence. In fact, the error rate of this method was 8%, so that it can be implemented for detection of dental caries and restoration. Using some parameters, it is possible that the error rate can be even reduced below 0.5%.