Assessment of salivary miRNA, clinical, and demographic characterization in colorectal cancer diagnosis.

AIM: Colorectal cancer (CRC), as the third most frequent malignancy in the world, is the fourth major cause of cancer-related mortality. Its early detection contributes significantly to a reduction in mortality. The objective of this case-control research was to analyze the salivary expression of microRNA-29a (miR-29a) and microRNA-92a (miR-92a), and also to consider demographic, clinical, and nutritional habits for differentiation between CRC patients and healthy controls, especially in the early stages. METHOD: A standard checklist was used to obtain the demographic information, clinical features, and dietary habits of the case and control groups. Samplings of whole unstimulated saliva samples were obtained from 33 healthy persons and 42 CRC patients. Through real-time PCR, statistical analyses, and machine learning analyses, miR-29a and miR-92a salivary expression levels were evaluated. RESULTS: The mean salivary expression of miR-92a and miR-29a in CRC patients was significantly higher than in healthy controls (p < 0.001). The area under the receiver operating characteristic curve for miR-92a and miR-29a salivary biomarkers was 0.947 and 0.978, respectively. The sensitivity and specificity values for miR-92a were 95.24 % and 84.85 %, respectively, whereas sensitivity and specificity for miR-29a were equal to 95.20 % and 87.88 %, respectively. Multiple logistic regressions considering demographics, clinical features, and nutritional habits led to values of 95.35 % and 96.88 % as sensitivity and specificity, respectively, and machine learning analysis led to values of 88.89 % and 86.67 % as sensitivity and specificity, respectively. CONCLUSION: CRC could be accurately diagnosed based on miR-92a and miR-29a levels in saliva. Statistical analysis and machine learning might develop cost-effective models for the distinction of CRC using a noninvasive technique.

Cytotoxic, anti-proliferative, and apoptotic evaluation of Ramalina sinensis (Ascomycota, Lecanoromycetes), lichenized fungus on oral squamous cell carcinoma cell line; in-vitro study.

BACKGROUND: Scientists and medical professionals are actively striving to improve the efficacy of treatment methods for oral squamous cell carcinoma (OSCC), the most frequently occurring cancer within the oral cavity, by exploring the potential of natural products. The active pharmacological compounds found in lichenized fungi have shown potential for aiding in cancer treatment. Recent research aims to evaluate the impact of the lichenized fungus Ramalina sinensis (R. sinensis) on the cell viability and apoptosis of OSCC cell lines, considering the anti-inflammatory and anti-cancer capabilities of lichens. METHODS: Ramalina sinensis (Ascomycota, Lecanoromycetes) was selected for investigation of its effects on a human oral squamous cell carcinoma cell line. Acetone and methanol extracts of R. sinensis on an OSCC cell line (KB cell line, NCBI Code: C152) were investigated. Viability was assessed by MTT assay analysis, and apoptotic cells were measured using flow cytometry analysis. Scratch assay was used to assess cell migration. The chemical composition and metabolic profiling of R. sinensis were investigated. RESULTS: The growth and multiplication of KB cells were observed to undergo a gradual but remarkable inhibition when exposed to various concentrations. Specifically, concentrations of 6.25, 12.5, 25, 50, 100, and 200 µg/mL exhibited a significant suppressive effect on the proliferation of KB cells. The inhibition of cell proliferation exhibited a statistically significant difference between the extracts obtained from acetone and methanol. Flow cytometry results show an increase in apoptosis of OSCC cells by acetone extract. R. sinensis exerted a concentration-dependent inhibitory effect on the migration of OSCC cells. The chemical composition of R. sinensis was investigated using liquid chromatography positive ion electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), and 33 compounds in the acetone and methanol extracts of R. sinensis were detected. CONCLUSION: The findings provide evidence supporting the beneficial effects of R. sinensis extract on inducing apoptosis in OSCC cells and exerting anti-cancer properties.

Transdifferentiation of periodontal ligament stem cells into acinar cells using an indirect co-culture system.

Serous Acinar Cells (ACs) are mature and functional secretory epithelial cells that develop and complete through other stem cells at the end of the ductal system. So, the regeneration of the salivary gland damaged by radiation does not occur without cell therapy. Todays, an accessible tissue like the Periodontal Ligament (PDL) of the tooth was considered to easily extract the Mesenchymal Stem Cells (MSCs). In-vitro differentiation of stem cells before transplantation to damaged tissue reduces the risk of tumorigenesis. This study was conducted to evaluate the feasibility of differentiation of PDLSCs into salivary acinar cells by a co-culture system. PDLSCs were isolated from adult human PDL tissue and co-cultured with rat parotid ACs using an indirect co-culture system. The transdifferentiation of PDLSCs was evaluated by PCR of Aquaporin 5 (AQP5) and Carbonic anhydrase 6 (CA6) genes, then quantitative real-time PCR was used to measure the gene expression levels. The data were analyzed by ANOVA. Specific bond with the correct size on 6% acrylamide gel and TBE5X buffer showed the expression of AQP5 and CA6 in PDLSCs co-cultured with acinar cells. RT-PCR revealed co-cultured PDLSCs with or without KGF (Keratinocyte Growth Factor) showed significantly increased expression of AQP5 genes in compared to the initial PDLSCs. Expression of AQP5 and CA6, indicating successful transdifferentiation of PDLSCs into ACs, in co-culture system for 3 weeks.

Effect of synbiotic mouthwash on oral mucositis induced by radiotherapy in oral cancer patients: a double-blind randomized clinical trial.

PURPOSE: Considering the complex pathobiology of oral mucositis, especially in oral cancer patients, the prevention and treatment of oral mucositis in patients undergoing radiotherapy remains an essential and clinically crucial unmet need. The present study aims to investigate and compare the effects of synbiotic mouthwash with normal saline mouthwash on the prevention and control of radiotherapy-induced oral mucositis in oral cancer patients. METHODS: Double-blind, randomized clinical trial (RCT) performed on 64 oral cancer patients who underwent radiotherapy (IRCT20201106049288N1, registration date: 2020-12-23). Patients were divided randomly into the case (32 subjects) and control (32 subjects) groups. All patients underwent intensity-modulated radiotherapy and received 6000 cGY of radiotherapy in 34 fractions. All patients received the usual treatment for mucositis, but in the case group, synbiotic mouthwash was prescribed and in the control group, normal saline mouthwash was prescribed from a day before the start to the end of radiotherapy treatment. Patients were monitored every session for 6 weeks to check the progression, oral involvement severity, and mucositis grade. RESULTS: The case group showed a significant reduction in the oral mucositis severity. The mucositis grade in the case group from the 7th session of oral examination was significantly lower than the control (p < 0.05), and this significant difference persisted until the last session of oral examination. Incidence rates of severe oral mucositis (grade 3) during the treatment period were 11.59% in the case and 36.45% in control (p < 0.001). CONCLUSION: Synbiotic mouthwash significantly reduces and prevents oral mucositis intensity in oral cancer patients undergoing radiotherapy.

Lineage and phylogenetic analysis of HPV-16, -18 in saliva of HNSCC patients

Aim: Head and Neck Squamous Cell Carcinoma (HNSCC) is a global health problem whose incidence varies by geographic region and race according to risk factors. Human papillomavirus (HPV) infection is a significant risk factor for HNSCC. HPV-16 and HPV-18 are two forms of HPV that are carcinogenic. HNSCCs that are HPV positive have a better prognosis rather than HPV negative. The purpose of this research was to characterize HPV-16, -18 variations in the saliva of HNSCC patients by examining the genetic diversity of HPV-16, -18 utilizing the full E6, E7, and L1 genes. Methods:The case-control research included 15 patients with HNSCC and 15 healthy volunteers. Unstimulated entire saliva samples were obtained from the case and control groups by spitting method. Genomic DNA was isolated from all saliva samples. A PCR reaction was used to determine the presence of HPV in saliva. HPV-positive samples were genotyped and data were analyzed. We conducted a variant study on the HPV-16, -18 E6, and E7 genes. Results: Three patients with HNSCC were HPV-positive for two HPV genotypes out of 30 people diagnosed with HPV-DNA. HPV-16 and -18 were the most common genotypes. The HPV-16, -18 E6, and E7 genes were sequenced and compared to the HPV-16, -18 (E6, E7) prototype sequence. In all, HPV-16 lineages A1 and HPV-18 lineages A3 were discovered. Conclusion: Regarding the variation of HPV found in Iranian HNSCC patients, the need for further studies in HPV genotyping was seen. Sequencing HPV genes in HNSCC may help answer questions about HPV genotyping in the Iranian population. HPV genotype analysis aids in the development of vaccinations against HNSCC, halting disease progression and preventing HPV-associated HNSCC

Three-dimensional bioprinting of mucoadhesive scaffolds for the treatment of oral mucosal lesions; an in vitro study.

BACKGROUND: Chronic oral lesions could be a part of some diseases, including mucocutaneous diseases, immunobullous diseases, gastrointestinal diseases, and graft versus host diseases. Systemic steroids are an effective treatment, but they cause unfavorable and even severe systemic side effects. Discontinuation of systemic corticosteroids or other immunosuppressive drugs leads to relapse, confirming the importance of long-term corticosteroid use. The present study aims to fabricate a mucoadhesive scaffold using three-dimensional (3D) bioprinting for sustained drug delivery in oral mucosal lesions to address the clinical need for alternative treatment, especially for those who do not respond to routine therapy. METHODS: 3D bioprinting method was used for the fabrication of the scaffolds. Scaffolds were fabricated in three layers; adhesive/drug-containing, backing, and middle layers. For evaluation of the release profile of the drug, artificial saliva was used as the release medium. Mucoadhesive scaffolds were analyzed using a scanning electron microscope (SEM) and SEM surface reconstruction. The pH of mucoadhesive scaffolds and swelling efficacy were measured using a pH meter and Enslin dipositive, respectively. A microprocessor force gauge was used for the measurement of tensile strength. For the evaluation of the cytotoxicity, oral keratinocyte cells' survival rate was evaluated by the MTT method. Folding endurance tests were performed using a stable microsystem texture analyzer and analytic probe mini tensile grips. RESULTS: All scaffolds had the same drug release trend; An initial rapid explosive release during the first 12 h, followed by a gradual release. The scaffolds showed sustained drug release and continued until the fourth day. The pH of the surface of the scaffolds was 5.3-6.3, and the rate of swelling after 5 h was 28 ± 3.2%. The tensile strength of the scaffolds containing the drug was 7.8 ± 0.12 MPa. The scaffolds were non-irritant to the mucosa, and the folding endurance of the scaffolds was over three hundred times. CONCLUSION: The scaffold fabricated using the 3D bioprinting method could be suitable for treating oral mucosal lesions.

Salivary noncoding RNA in the diagnosis of pancreatic cancer: Systematic review and meta-analysis.

BACKGROUND: Pancreatic cancer is considered one of the most deadly malignancies, primarily because of its diagnostic challenges. We performed a systematic review and diagnostic meta-analysis to evaluate the diagnostic value of noncoding salivary RNAs in pancreatic cancer diagnosis. METHODS: Our investigation involved pertinent studies published in PubMed, Scopus, Web of Science, LIVIVO, Ovid and also the Google Scholar search engine. Specificity and sensitivity were calculated, as were positive and negative likelihood ratios (PLR and NLR), and the diagnostic odds ratio (DOR). The summary receiver-operating characteristics and area under the curve were plotted and assessed. RESULTS: This meta-analysis and systematic review involved and examined five studies that contained 145 study units with a total of 2731 subjects (1465 pancreatic cancer patients versus 1266 noncancer controls). The pooled specificity, sensitivity, NLR, PLR and DOR were 0.783 (95% CI: 0.759-0.805), 0.829 (95% CI: 0.809-0.848), 0.309 (95% CI: 0.279-0.343), 3.386 (95% CI: 2.956-3.879) and 18.403 (95% CI: 14.753-22.954), respectively, with the area under the curve (AUC) equal to 0.882. Subgroup analyses were conducted based on the saliva type (unstimulated and stimulated), mean age of patients, sample size, type of control, serum carbohydrate antigen 19-9 (CA19-9) level and type of salivary noncoding RNA (microRNA (miRNA) and long noncoding RNA (lncRNA)). CONCLUSIONS: The results of our systematic review and meta-analysis suggest that noncoding RNA biomarkers in the stimulated saliva could be a promising approach for accurate pancreatic cancer diagnosis in the early stages.

Assessment of the methylene blue mediated photodynamic therapy on BCL2 and BAX genes expression at mRNA level and apoptosis of head and neck squamous cell carcinoma cell line.

AIM: This study aimed to assess the effect of photodynamic therapy (PDT) on apoptosis of head and neck squamous cell carcinoma (HNSCC) cells by flow cytometry and evaluating BAX and BCL2 genes expression.

Evaluation of CSTB and DMBT1 expression in saliva of gastric cancer patients and controls.

BACKGROUND: Gastric cancer (GC) is the fifth most common cancer and the third cause of cancer deaths globally, with late diagnosis, low survival rate, and poor prognosis. This case-control study aimed to evaluate the expression of cystatin B (CSTB) and deleted in malignant brain tumor 1 (DMBT1) in the saliva of GC patients with healthy individuals to construct diagnostic algorithms using statistical analysis and machine learning methods. METHODS: Demographic data, clinical characteristics, and food intake habits of the case and control group were gathered through a standard checklist. Unstimulated whole saliva samples were taken from 31 healthy individuals and 31 GC patients. Through ELISA test and statistical analysis, the expression of salivary CSTB and DMBT1 proteins was evaluated. To construct diagnostic algorithms, we used the machine learning method. RESULTS: The mean salivary expression of CSTB in GC patients was significantly lower (115.55 ± 7.06, p = 0.001), and the mean salivary expression of DMBT1 in GC patients was significantly higher (171.88 ± 39.67, p = 0.002) than the control. Multiple linear regression analysis demonstrated that GC was significantly correlated with high levels of DMBT1 after controlling the effects of age of participants (R2 = 0.20, p < 0.001). Considering salivary CSTB greater than 119.06 ng/mL as an optimal cut-off value, the sensitivity and specificity of CSTB in the diagnosis of GC were 83.87 and 70.97%, respectively. The area under the ROC curve was calculated as 0.728. The optimal cut-off value of DMBT1 for differentiating GC patients from controls was greater than 146.33 ng/mL (sensitivity = 80.65% and specificity = 64.52%). The area under the ROC curve was up to 0.741. As a result of the machine learning method, the area under the receiver-operating characteristic curve for the diagnostic ability of CSTB, DMBT1, demographic data, clinical characteristics, and food intake habits was 0.95. The machine learning model's sensitivity, specificity, and accuracy were 100, 70.8, and 80.5%, respectively. CONCLUSION: Salivary levels of DMBT1 and CSTB may be accurate in diagnosing GCs. Machine learning analyses using salivary biomarkers, demographic, clinical, and nutrition habits data simultaneously could provide affordability models with acceptable accuracy for differentiation of GC by a cost-effective and non-invasive method.

Salivary biomarkers in breast cancer diagnosis: A systematic review and diagnostic meta-analysis.

BACKGROUND: Salivary diagnostics and their utility as a nonaggressive approach for breast cancer diagnosis have been extensively studied in recent years. This meta-analysis assesses the diagnostic value of salivary biomarkers in differentiating between patients with breast cancer and controls. METHODS: We conducted a meta-analysis and systematic review of studies related to salivary diagnostics published in PubMed, EMBASE, Scopus, Ovid, Science Direct, Web of Science (WOS), and Google Scholar. The articles were chosen utilizing inclusion and exclusion criteria, as well as assessing their quality. Specificity and sensitivity, along with negative and positive likelihood ratios (NLR and PLR) and diagnostic odds ratio (DOR), were calculated based on random- or fixed-effects model. Area under the curve (AUC) and summary receiver-operating characteristic (SROC) were plotted and evaluated, and Fagan's Nomogram was evaluated for clinical utility. RESULTS: Our systematic review and meta-analysis included 14 papers containing 121 study units with 8639 adult subjects (4149 breast cancer patients and 4490 controls without cancer). The pooled specificity and sensitivity were 0.727 (95% CI: 0.713-0.740) and 0.717 (95% CI: 0.703-0.730), respectively. The pooled NLR and PLR were 0.396 (95% CI: 0.364-0.432) and 2.597 (95% CI: 2.389-2.824), respectively. The pooled DOR was 7.837 (95% CI: 6.624-9.277), with the AUC equal to 0.801. The Fagan's nomogram showed post-test probabilities of 28% and 72% for negative and positive outcomes, respectively. We also conducted subgroup analyses to determine specificity, sensitivity, DOR, PLR, and NLR based on the mean age of patients (≤52 or >52 years old), saliva type (stimulated and unstimulated saliva), biomarker measurement method (mass spectrometry [MS] and non-MS measurement methods), sample size (≤55 or >55), biomarker type (proteomics, metabolomics, transcriptomics and proteomics, and reagent-free biophotonic), and nations. CONCLUSION: Saliva, as a noninvasive biomarker, has the potential to accurately differentiate breast cancer patients from healthy controls.

Evaluation of exposure to environmental stressors on heat-shock protein 70 expression in normal oral keratinocyte cells.

OBJECTIVES: This study aimed to investigate the effect of cortisol, estrogen, and nicotine on heat shock protein 70 (HSP70) expressions at the level of normal oral mucosa keratinocyte cells. METHODS: In this in vitro study, keratinocytes were derived from rat oral cavity and cultured. Stressors were applied, including three groups, group 1: estrogen to simulate the postmenopausal state; group 2: cortisol to simulate psychological stress situation; group 3: nicotine to simulate smoking state. To determine the exact nature of keratinocyte cells, two surface markers, cytokeratin 18 and cytokeratin 14 were examined using the flow cytometry method. Then, the immunocytochemistry technique with three repetitions in each group was used to evaluate the HSP70 expression before and after applying the stressor. RESULTS: HSP70 expressions in the three stressor groups (estrogen, cortisol, and nicotine) were significantly lower than in the control group (p = 0.0001). The HSPs expression difference between cortisol and nicotine was statistically significant (p = 0.0001). Based on the results of MTT analysis, the mean cell viability of oral mucosal keratinocytes in all three intervention groups decreased compared to the control group. In the cortisol and nicotine groups, cell death was significantly higher than in the control group. In the estrogen group, cell death was significantly lower than in the nicotine group (p > 0.05). CONCLUSIONS: The specific concentrations of cortisol, estrogen, and nicotine as stressors can effectively reduce the expression of HSP70 in normal oral mucosal keratinocytes. These phenomena can be effective in cell viability and the development of oral lichen planus.

Salivary cystatin S levels in children with early childhood caries in comparison with caries-free children; statistical analysis and machine learning.

BACKGROUND: Early childhood caries is the most common infectious disease in childhood, with a high prevalence in developing countries. The assessment of the variables that influence early childhood caries as well as its pathophysiology leads to improved control of this disease. Cystatin S, as one of the salivary proteins, has an essential role in pellicle formation, tooth re-mineralization, and protection. The present study aims to assess salivary cystatin S levels and demographic data in early childhood caries in comparison with caries-free ones using statistical analysis and machine learning methods. METHODS: A cross-sectional, case-control study was undertaken on 20 cases of early childhood caries and 20 caries-free children as a control. Unstimulated whole saliva samples were collected by suction. Cystatin S concentrations in samples were determined using human cystatin S ELISA kit. The checklist was collected from participants about demographic characteristics, oral health status, and dietary habits by interviewing parents. Regression and receiver operating characteristic (ROC) curve analysis were done to evaluate the potential role of cystatin S salivary level and demographic using statistical analysis and machine learning. RESULTS: The mean value of salivary cystatin S concentration in the early childhood caries group was 191.55 ± 81.90 (ng/ml) and in the caries-free group was 370.06 ± 128.87 (ng/ml). T-test analysis showed a statistically significant difference between early childhood caries and caries-free groups in salivary cystatin S levels (p = 0.032). Investigation of the area under the curve (AUC) and accuracy of the ROC curve revealed that the logistic regression model based on salivary cystatin S levels and birth weight had the most and acceptable potential for discriminating of early childhood caries from caries-free controls. Furthermore, using salivary cystatin S levels enhanced the capability of machine learning methods to differentiate early childhood caries from caries-free controls. CONCLUSION: Salivary cystatin S levels in caries-free children were higher than the children with early childhood caries. Results of the present study suggest that considering clinical examination, demographic and socioeconomic factors, along with the salivary cystatin S levels, could be usefull for early diagnosis ofearly childhood caries in high-risk children; furthermore, cystatin S is a protective factor against dental caries.

Assessment of MicroRNA-15a and MicroRNA-16-1 Salivary Level in Oral Squamous Cell Carcinoma Patients.

BACKGROUND: Squamous Cell Carcinoma (SCC) includes more than 90% of malignancies of the oral cavity. Early diagnosis could effectively improve patients' quality of life and treatment outcomes of oral cancers. MicroRNAs as non-encoding genes have great potential to initiate or suppress cancer progression. Recent studies have shown that disruption of micro-RNA regulation is a common occurrence in cancers. OBJECTIVE: This study set out to evaluate the expression of microRNA-15a (miR-15a) and microRNA- 16-1 (miR-16-1) in the saliva of Oral Squamous Cell Carcinoma (OSCC) patients in comparison with a healthy control group. METHODS: This case-control study was performed on fifteen patients with OSCC and fifteen healthy volunteers as the control group. A 5 ml of non-stimulating whole saliva was collected by spitting method from patients and controls and stored at -70°C. The expression of miR-15a and miR-16-1 was investigated using quantitative Reverse-Transcription Polymerase Chain Reaction (RT-qPCR). RESULTS: MiR-15a and miR-16-1 were downregulated in OSCC patients compared with the control group (p<0.001). The sensitivity of miR-15a and miR-16-1 in differentiating OSCC patients from healthy individuals was 93.3% and 86.67%, respectively, and their specificity was 86.67% and 92.33%, respectively. The diagnostic accuracy of miR-15a was 90%, and miR-16-1 was 93.3%. CONCLUSION: The present study showed a decrease in the relative expression of miR-15a and miR-16-1 in OSCC patients compared with healthy individuals. It is probable to introduce salivary values of miR-15a and miR-16-1 as a non-invasive tool for early detection of OSCC. Decreased expression of miR-15a and miR-16-1 in OSCC indicates the possible effective role of these genes in OSCC etiopathogenesis.

Effect of photodynamic therapy on expression of HRAS, NRAS and caspase 3 genes at mRNA levels, apoptosis of head and neck squamous cell carcinoma cell line.

OBJECTIVES: This study aimed to assess the effect of photodynamic therapy (PDT) on expression of CASP3, NRAS and HRAS genes at mRNA levels, and apoptosis of head and neck squamous cell carcinoma (HNSCC) cell line. MATERIALS AND METHODS: In order to complete the present in vitro study, HNSCC cell line (NCBI C196 HN5) purchased from Pasteur Institute. Cells were divided into four groups; Group 1: photodynamic treatment (laser + methylene blue (MB) as photosensitizer), group 2: MB, group 3: laser (with 660 nm wavelength), and group 4: control (without any treatment). To determine the optimal concentration of MB, in a pilot study, toxicity of MB in different concentration was assessed using MTT assay. Cells in group 1, 2 and 3 was treated at optimal concentration of MB (1.6 µg/mL). Gene expression at mRNA levels was assessed after 24 h incubation, using real-time (qRT)-PCR. The expression of BAX and BCL2 genes at the mRNA levels was analyzed to evaluate apoptosis. 2-ΔΔCt values of BCL2, BAX, CASP3, NRAS, and HRAS in groups was analyzed using ANOVA. Tukey's HSD and Games Howell test was used to compare between two groups. RESULTS: Over-expression of BAX (p < 0.001), CASP3 (p < 0.001) and down-regulation of BCL2 (p = 0.004), HRAS (p = 0.023) and NRAS (p = 0.045) were noted in group 1 (PDT), compared with the control group. Treatment by laser alone induce down-regulation of CASP3 (p < 0.05), BAX (p < 0.05), BCL2 (p > 0.05), HRAS (p > 0.05) and NRAS (p > 0.05). CONCLUSION: PDT caused down-regulation of NRAS, HRAS and BCL2 and over-expression of CASP3 and BAX genes at mRNA levels in HNSCC cell line. The present study raises the possibility that the role of MB on BCL2 down-regulation and BAX and CASP3 over-expression was higher than laser alone while it seems that laser alone was more effective than MB in HRAS and NRAS down-regulation.

Er,Cr:YSGG laser surface treatment of gamma titanium aluminide: Scanning electron microscopy-energy-dispersive X-ray spectrometer analysis, wettability and Eikenella corrodens and Aggregatibacter actinomycetemcomitans bacteria count-in vitro study.

Dental implants play an important role in oral health. Titanium dental implants must endure the complex microflora environment of the oral cavity. Moreover, bacterial infections have been considered as one of the most important factors of implant failure. The issue of dental improvement through modification of chemical composition and surface treatment has received considerable critical attention. γ-TiAl as a novo biocompatible material revealed a slower corrosion rate in biological media rather Ti-6Al-4V. The objective of this study is to investigate the effect of Er,Cr:YSGG laser on γ-TiAl in comparison with sandblasted and acid-etched samples as the control groups and machined samples.Wettability, surface roughness, surface topography, scanning electron microscopy-energy dispersive X-ray spectrometer analysis of surface and subsurface of samples were investigated and bacteria counts of two periodontal bacterial strains (Aggregatibacter actinomycetemcomitans and Eikenella corrodens) were evaluated on the Er,Cr:YSGG laser surface-treated sandblasted and acid-etched and machined samples.The results of this investigation show that Er,Cr:YSGG laser surface treatment affects surface roughness, surface topography, wettability, chemical composition of the surface and bacteria count. Scanning electron microscopy-energy dispersive X-ray spectrometer analysis of the sample revealed the increment of titanium and oxygen content and reduction of aluminum content in the surface and subsurface layer. A. actinomycetemcomitans and E. corrodens count were found from the lowest level to highest in the sandblasted and acid-etched samples, laser samples and machined samples, respectively.Using controlled parameters of Er,Cr:YSGG laser ensured no significant adverse alteration. The findings to emerge from this study revealed the significant correlation between microbial count and wettability. Furthermore, the contact angle strongly correlated with surface roughness.

Comparison of salivary nitric oxide and oral health in diabetic patients with and without xerostomia.

BACKGROUND AND OBJECTIVE: Diabetes mellitus (DM) is a chronic multi-systemic metabolic disorder; diabetic patients are more prone to xerostomia and oral health problems than others. There are evidences that nitric oxide (NO) plays an important role in healthy salivary gland function, prevention of insulin resistance and progression of diabetes mellitus. The aim of this study was to compare the salivary NO level between type 2 diabetic (T2DM) patients with and without xerostomia. METHODS: In this case control study, 70 patients with T2DM, which were matched according to age, sex, type of disease control, were enrolled conveniently. The subjects based on abeslang test were allocated to the two groups; 35 patients with xerostomia and 35 patients without xerostomia. Unstimulated whole saliva was collected by spitting method. NO levels was measured by ELISA method using Griess reaction. Data was analyzed using t-test, ANOVA and logistic regression analysis to examine the association of salivary NO and xerostomia. RESULTS: The mean and standard deviation of salivary NO in the diabetic subjects with xerostomia was significantly lower than diabetic subjects without xerostomia (138 ± 94.58 µmol/L vs. 356.61 ± 302.81 µmol/L (P-value = 0.001). In logistic regression analysis, salivary NO level was associated with 0.994 fold decreased risk of xerostomia in diabetic subjects after adjustment for age, gender, FBS and HbA1c. CONCLUSIONS: The present study indicates salivary nitric oxide level was a predictor of xerostomia in diabetic patients. More longitudinal studies are necessary to understand the association of salivary NO level with diabetes-induced xerostomia.

Comparison of the effect of regular and probiotic cake (Bacillus coagulans) on salivary pH and Streptococcus mutans count.

BACKGROUND: Dental caries is considered the most common infectious disease in humans worldwide. Cariogenesis is the outcome of a complex interaction between the host's oral flora and diet. The consumption of snacks such as cake, which have the potential to promote dental caries, has increased. OBJECTIVES: The aim of this study was to investigate the effect of including probiotic bacteria (Bacillus coagulans - B. coagulans) in consumed snack cake on the Streptococcus mutans (S. mutans) count and salivary pH. MATERIAL AND METHODS: We conducted a randomized, double-blind, cross-sectional cohort study on 40 healthy volunteers. The subjects were divided into 2 groups. In the 1st group, the subjects consumed probiotic cake as breakfast for 1 week and then, following a 4-week wash-out period, consumed regular cake as breakfast for 1 week. In the other group, the administration of probiotic and regular cake was reversed. For both groups, samples of at least 5 mL of non-stimulated saliva were collected using the spitting technique before and after the 1st and the 6th week. A colony counter was used to determine the number of S. mutans colonies. Salivary pH was measured before eating (8-9 a.m.). RESULTS: We detected no statistically significant difference in the S. mutans count before and after the consumption of probiotic cake, but noted a statistically significant difference in the count before and after the consumption of regular cake. We did not detect a significant difference in salivary pH with respect to the consumption of probiotic and regular cake, although the consumption of both foods caused a drop in salivary pH. CONCLUSIONS: The addition of probiotic bacteria to sweet snack cake caused a minimal increase in the salivary count of S. mutans, a bacterial species with a definite role in cariogenesis, but did not impact salivary pH. Since probiotic cake has a slight impact on the S. mutans count, it is preferred over regular cake as a snack food.

Three-dimensional simulation of human teeth and its application in dental education and research.

Background: A comprehensive database, comprising geometry and properties of human teeth, is needed for dentistry education and dental research. The aim of this study was to create a three-dimensional model of human teeth to improve the dental E-learning and dental research. Methods: In this study, a cross-section picture of the three-dimensional model of the teeth was used. CT-Scan images were used in the first method. The space between the cross- sectional images was about 200 to 500 micrometers. Hard tissue margin was detected in each image by Matlab (R2009b), as image processing software. The images were transferred to Solidworks 2015 software. Tooth border curve was fitted on B-spline curves, using the least square-curve fitting algorithm. After transferring all curves for each tooth to Solidworks, the surface was created based on the surface fitting technique. This surface was meshed in Meshlab-v132 software, and the optimization of the surface was done based on the remeshing technique. The mechanical properties of the teeth were applied to the dental model. Results: This study presented a methodology for communication between CT-Scan images and the finite element and training software through which modeling and simulation of the teeth were performed. In this study, cross-sectional images were used for modeling. According to the findings, the cost and time were reduced compared to other studies. Conclusion: The three-dimensional model method presented in this study facilitated the learning of the dental students and dentists. Based on the three-dimensional model proposed in this study, designing and manufacturing the implants and dental prosthesis are possible.