Effects of various disinfectants on surface roughness and color stability of thermoset and 3D-printed acrylic resin.

Denture cleansers are extensively utilized to inhibit the colonization of various Candida species. Currently, additive technology in denture fabrication has become more prevalent. This study aims to assess the impact of disinfectants on the surface roughness and color stability of distinct denture bases. Disc-shaped samples (N=66) were exposed to three different disinfectants: 0.5% sodium hypochlorite, 1% hydrogen peroxide, and 2% chlorhexidine. The samples underwent evaluation via spectrophotometry and profilometry, respectively. Data analysis was conducted utilizing analysis of variance (ANOVA) (p < 0.05). Within the heat-cured group, sodium hypochlorite resulted in the most notable change in surface roughness (0.2 µm), while chlorhexidine exhibited the least impact (0.001 µm), showing a significant difference (p <0.008). The color change (ΔE) for 3D-printed samples immersed in all disinfectants was higher compared to heat-cured samples. Among the heat-cured samples, chlorhexidine induced the highest ΔE (2.76), while sodium hypochlorite resulted in the lowest (ΔE = 1.44), and this difference was statistically significant (p <0.008). Chlorhexidine caused the most significant color alteration among the solutions, while sodium hypochlorite induced the most considerable changes in surface roughness.

Association of root morphology of mandibular second molars on panoramic-like and axial views of cone-beam computed tomography.

BACKGROUND: Knowledge about the anatomy and morphology of the root canal system is essential for successful surgical and non-surgical root canal treatments. However, precise assessment of the root morphology and anatomy is not often possible on two-dimensional radiographs. This study aimed to investigate the association of root morphology of mandibular second molars on panoramic-like and axial views of cone-beam computed tomography (CBCT). METHODS: This cross-sectional study evaluated 1,231 CBCT scans of mandibular second molars obtained between October 2018 and February 2022 that were retrieved from the archives of a private radiology clinic. Panoramic-like images were reconstructed from the CBCT scans. The root morphology of mandibular second molars was classified on panoramic-like images as type 1, 2, 3, 4, or 5. The root pattern on axial CBCT images was classified into three types of single, double and C-shaped. The association of root morphology on panoramic-like and axial CBCT views was analyzed by the Chi-square test and Fisher's exact test at 0.05 level of significance. RESULTS: Of all, 62.7% of mandibular second molars were type 1; out of which, 97.3% had a double-root pattern on axial CBCT images. Also, 28.6% of them were type 2; of which, 92.6% had a double-root pattern. Moreover, 3.9% were type 3; of which, 47.9% had a C-shaped pattern; 0.9% were type 4, and 45.5% of them showed a single-root pattern; 3.8% were type 5 with 76.6% of them showing a single-root pattern. The prevalence of C-shaped canals was higher in females, and most C-shaped canals had a C3 pattern. CONCLUSION: Root morphology on panoramic-like CBCT views had a strong association with the root canal pattern on axial CBCT views. According to the results, mandibular second molars with a type 3 morphology on panoramic-like CBCT images are highly probable to have a C-shaped canal.

Shear bond strength of orthodontic brackets to specimens fabricated from temporary restorative materials by 3D-printing, CAD/CAM technology, and the conventional technique after surface treatment by sandblasting and laser.

OBJECTIVES: This study assessed the shear bond strength (SBS) of stainless steel (SS) orthodontic brackets to specimens fabricated from polymethyl methacrylate (PMMA) temporary restorative material by 3D-printing, computer-aided design/computer-aided manufacturing (CAD/CAM) technology, and the conventional technique, after surface treatment by sandblasting and laser. MATERIAL AND METHODS: In this in vitro study, 60 disc-shaped specimens with 8mm diameter and 1mm height were fabricated from PMMA temporary restorative material by 3D-printing, CAD/CAM, and the conventional technique. In each group (n=20), half of the specimens were sandblasted while the other half underwent Er,Cr:YSGG laser irradiation. Brackets were bonded to the specimens and underwent thermocycling followed by SBS testing. Data were analysed by one-way ANOVA, independent t-test, and LSD test (alpha=0.05). RESULTS: A significant difference existed among the three fabrication methods in SBS in both laser (P<0.001) and sandblasting (P<0.001) surface treatment groups. In laser group, the mean SBS of CAD/CAM (P=0.000) and conventional (P=0.000) groups was significantly lower than that of 3D-printing group. In sandblasting group, the SBS of CAD/CAM group was significantly lower than 3D-printing (P=0.000) and conventional (P=0.000) groups. The mean SBS of laser-treated specimens was significantly higher than sandblasted specimens in 3D-printing group (P=0.000), and significantly lower than sandblasted specimens in the conventional group (P=0.000). A significantly higher SBS was obtained by laser treatment compared with sandblasting irrespective of the fabrication method (P=0.000). CONCLUSION: The highest SBS of SS orthodontic brackets to temporary restorative material was recorded for 3D-printed specimens treated by Er,Cr:YSGG laser irradiation.

Clinical evaluation of chitosan/polycaprolactone nanofibrous scaffolds releasing tetracycline hydrochloride in periodontal pockets of patients with chronic periodontitis.

Background: The role of bacteria in the initiation and progression of periodontitis has led to a great interest in using antibiotics to suppress pathogenic microbiota. Considering the drawbacks of systemic antibiotics' application, local delivery systems directly in the periodontal pocket can be helpful. Therefore, the effect of an efficient tetracycline-loaded delivery system was investigated on the clinical parameters of periodontitis. Methods: In this clinical trial with a split-mouth design, 10 patients with periodontitis with pocket depths≥5 mm were included. After scaling and root planing (SRP) for all the patients, one side of the mouth was randomly considered as the control group, and on the other side, chitosan/polycaprolactone (PCL) nanofibrous films containing tetracycline (5%) were placed in pockets of 5 mm and deeper. Clinical measurements of pocket probing depth (PPD), clinical attachment loss (CAL), and bleeding on probing (BOP) indices were made at the beginning and after 8 weeks of intervention. PPD, CAL, and BOP parameters were compared between the control and test groups before and after the intervention with paired t tests using SPSS 24. The significance level of the tests was considered at P<0.05. Results: The mean PPD, CAL, and BOP in both the control (SRP) and test (LDDs) groups decreased after 8 weeks. A significant difference was detected in reducing PPD, BOP, and CAL after 8 weeks in 5-mm pockets, and the mean values were higher in the test group than in the control (P<0.05). Conclusion: The local drug delivery system using chitosan/PCL nanofibrous films containing tetracycline can effectively control periodontal diseases by reducing pocket depth and inflammation and improving CAL without offering side effects, although further evaluations are needed.

Prediction the survival of patients with breast cancer using random survival forests for competing risks.

Objectives: Breast cancer (BC) is the most common cause of cancer death in Iranian women. Sometimes death from other causes precludes the event of interest and makes the analysis complicated. The purpose of this study was to identify important prognostic factors associated with survival duration among patients with BC using random survival forests (RSF) model in presence of competing risks. Also, its performance was compared with cause-specific hazard model. Methods: This retrospective cohort study assessed 222 patients with BC who were admitted to Ayatollah Khansari hospital in Arak, a major industrial city and the capital of Markazi province in Iran. The cause-specific Cox proportional hazards and RSF models were employed to determine the important risk factors for survival of the patients. Results: The mean and median survival duration of the patients were 90.71 (95%CI: 83.8-97.6) and 100.73 (95%CI: 89.2-121.5) months, respectively. The cause-specific model indicated that type of surgery and HER2 had statistically significant effects on the risk of death of BC. Moreover, the RSF model identified that HER2 was the most important variable for the event of interest. Conclusion: According to the results of this study, the performance of the RSF model was better than the cause-specific hazard model. Moreover, HER2 was the most important variable for death of BC in both of the models.

Comparison of shear bond strength of orthodontic stainless-steel brackets on temporary crowns fabricated by three different methods: An in vitro study.

BACKGROUND AND AIMS: Different methods are available for making temporary restorations. The purpose of this study was to determine and compare the shear bond strength of orthodontic brackets on temporary crowns made by three different methods. MATERIALS AND METHODS: In this experimental study, disc form samples (N=54) were made in dimensions 8×1mm, according to the manufacturer's instructions. In this study, we had three groups (N=18) based on manufacturing methods (3D printing, conventional, and CAD/CAM). Following surface preparation of the samples, the brackets were bonded in the centre of the discs. Before the shear bond strength test, the samples were subjected to the thermocycling process. The shear bond strength of brackets was measured by Universal Testing Machine. Data were analysed by one-way ANOVA and LSD post hoc test. RESULTS: The findings indicated that the mean shear bond strength of orthodontic stainless-steel brackets on temporary crowns varied between CAD/CAM and 3D printing methods (P<0.001) and also between CAD/CAM and conventional methods (P<0.001). The mean shear bond strength of orthodontic stainless steel brackets on temporary crowns was not different between 3D printing and conventional methods (P=0.7). CONCLUSION: The shear bond strength of orthodontic stainless-steel brackets bonded to temporary crowns fabricated by conventional and 3D printing methods was similar, and the shear bond strength in the samples fabricated by CAD/CAM method was lower than other specimens.

DIAGNOdent pen quantification of the synergy of NovaMin® in fluoride toothpaste to remineralize white spot lesions in patients with fixed orthodontic appliances: A double-blind, randomized, controlled clinical trial.

OBJECTIVES: White spot lesions (WSLs) are a real problem in patients with fixed orthodontic appliances with inadequate hygiene and eating habits. This study aimed at evaluating the synergic effects of NovaMin in fluoride toothpaste on remineralization of WSLs in patients with fixed orthodontic appliances. METHODS: In the present double-blind, randomized, controlled, parallel, clinical trial, Patients with a minimum of 1 WSL on the buccal surface of the anterior teeth and the first premolar on both arches were recruited between 12 February 2021 and 12 April 2021 at the Faculty of Dentistry of X. They were randomly divided into 2 groups, the control group receiving fluoride toothpaste (Sensodyne® Rapid Relief, England), and the study group receiving the fluoride-containing toothpaste and NovaMin (Sensodyne® Repair and Protect, England). A DIAGNOdent pen (KAVO Dental Corporation, Germany) was used to score the WSLs at baseline and then after the usage for 1 and 3months. The primary outcome measures were the difference in DIAGNOdent score in patients with fixed orthodontic appliances that used fluoride toothpaste and NovaMin/fluoride toothpaste. The secondary outcome measures were the intragroup comparison of the DIAGNOdent score in patients with fixed orthodontic appliances that used fluoride toothpaste and NovaMin/fluoride toothpaste. The type of toothpaste used was blinded for the participants, examiner, and data analyser. RESULTS: A sample size comprising 38 patients (19 patients in each group) was determined. In each group, statistical analysis was conducted on 18 patients. A patient in each group refused to contribute to the study. In both groups (P<0.001), the DIAGNOdent reading of the WSLs decreased significantly after 1 and at 3months, though no significant difference was found between the two groups at different intervals. Each patient had no adverse effects. CONCLUSIONS: In this 3-month follow-up study, NovaMin/fluoride toothpaste provided a slight improvement in WSL remineralisation, but not significant compared to fluoride toothpaste. NovaMin therefore did not have a significant synergistic effect. Both types of toothpaste can improve WSLs in orthodontic patients. THE CLINICAL TRIAL REGISTRATION NUMBER: IRCT20140215016582N5.

Effects of Hypertension Alone and in Comorbidity with Diabetes on Death within 30 Days among Inpatients with COVID-19 Infection.

BACKGROUND: Hypertension and diabetes are common comorbidities in patients with COVID-19 and could be influencing the mortality of such patients. The present study aimed to evaluate the effects of hypertension alone and in comorbidity with diabetes on the death within 30 days among inpatients with COVID-19 in presence of well-known determinates of COVID-19 death. STUDY DESIGN: A case-control study. METHODS: Four groups of COVID-19 inpatients including controls, diabetes alone, hypertension alone, and hypertension and diabetes comorbidities were defined. Each study groups did not have underlying diseases other than hypertension and diabetes. Demographic and general characteristics, underlying diseases, and hospital course events were extracted from medical records. The outcome of interest was alive at discharge/ death within 30 days after admission. Multivariable binary logistic analysis was employed to estimate the effect measures. RESULTS: The number of death within 30 days among controls (n=1359), diabetes alone (159), hypertension alone (406) and hypertension and diabetes comorbidities (188) were 12.68%, 15.72%, 20.74% and 26.74%, respectively. According to three multivariable analyses after adjusting older age, hospital length of stay, and intensive care unit (ICU) admission separately, the odds of death within 30 days in COVID-19 patients with having hypertension and diabetes comorbidities was 1.58, 2.13 and 1.91 times of patients without such comorbidities, respectively (P<0.015). The effect of hypertension alone was also significant after adjusting hospital length of stay and ICU admission but not for older age. CONCLUSION: Our results suggest that comorbidities, such as hypertension and diabetes may be associated with COVID-19-related deaths independent of other underlying diseases, older age, and adverse hospital course events.

Using Machine Learning Techniques to Predict Factors Contributing to the Incidence of Metabolic Syndrome in Tehran: Cohort Study.

BACKGROUND: Metabolic syndrome (MetS), a major contributor to cardiovascular disease and diabetes, is considered to be among the most common public health problems worldwide. OBJECTIVE: We aimed to identify and rank the most important nutritional and nonnutritional factors contributing to the development of MetS using a data-mining method. METHODS: This prospective study was performed on 3048 adults (aged ≥20 years) who participated in the fifth follow-up examination of the Tehran Lipid and Glucose Study, who were followed for 3 years. MetS was defined according to the modified definition of the National Cholesterol Education Program/Adult Treatment Panel III. The importance of variables was obtained by the training set using the random forest model for determining factors with the greatest contribution to developing MetS. RESULTS: Among the 3048 participants, 701 (22.9%) developed MetS during the study period. The mean age of the participants was 44.3 years (SD 11.8). The total incidence rate of MetS was 229.9 (95% CI 278.6-322.9) per 1000 person-years and the mean follow-up time was 40.5 months (SD 7.3). The incidence of MetS was significantly (P<.001) higher in men than in women (27% vs 20%). Those affected by MetS were older, married, had diabetes, with lower levels of education, and had a higher BMI (P<.001). The percentage of hospitalized patients was higher among those with MetS than among healthy people, although this difference was only statistically significant in women (P=.02). Based on the variable importance and multiple logistic regression analyses, the most important determinants of MetS were identified as history of diabetes (odds ratio [OR] 6.3, 95% CI 3.9-10.2, P<.001), BMI (OR 1.2, 95% CI 1.0-1.2, P<.001), age (OR 1.0, 95% CI 1.0-1.03, P<.001), female gender (OR 0.5, 95% CI 0.38-0.63, P<.001), and dietary monounsaturated fatty acid (OR 0.97, 95% CI 0.94-0.99, P=.04). CONCLUSIONS: Based on our findings, the incidence rate of MetS was significantly higher in men than in women in Tehran. The most important determinants of MetS were history of diabetes, high BMI, older age, male gender, and low dietary monounsaturated fatty acid intake.

Joint modelling of colorectal cancer recurrence and death after resection using multi-state model with cured fraction.

Curing of colorectal cancer (CRC) occurs at the time of resection but it is not immediately observable. If the cancer is not completely eliminated, the patient will not be cured of cancer and will experience recurrence as the tumor has regrown to a detectable size. The main propose of the present study was to assess the effects of different covariates on the probability of being cured as well as the time-to-recurrence, and time-to-death in CRC patients by using multi-state cure model. The information of 283 patients with CRC, who underwent resection, from 2000 to 2015 in Imam Khomeini Hospital of Hamadan, Iran, were analyzed. The results of multi-state cure model reveal that females and who experience metastasis were more likely to be apparently cured. It has been shown that sex has a significant effect on the time-to-recurrence given patient was in the not cured group. The survival time of patients of the not cured group was affected by the stage of disease. However, the survival of the apparently cured patients were affected by age at diagnosis and metastasis status. The multi-state cure model provided a flexible framework to study the effects of prognostic factors simultaneously on the transition between different states and the probability of being apparently cured of CRC.

Relationship of Frontal Sinus Size and Maturation of Cervical Vertebrae for Assessment of Skeletal Maturity.

OBJECTIVES: This study aimed to assess the relationship of frontal sinus height and width with the cervical vertebral maturation (CVM) for assessment of skeletal maturity. MATERIALS AND METHODS: This retrospective study evaluated lateral cephalograms of 132 patients between 8 to 21 years, including 66 males and 66 females. For each of the six stages of the CVM, 22 patients (11 males and 11 females) were evaluated. The Ertuk's method was used to measure the height and width of the frontal sinus. The sinus height to width ratio was calculated and considered as the sinus index. The CVM was evaluated on the same lateral cephalograms using the Baccetti's method. The correlation of frontal sinus height and width with the CVM was analyzed, and comparisons were made using independent t-test, ANOVA, Mann-Whitney test, and Kendall's tau-b correlation coefficient. RESULTS: The sinus width was 10.85±2.7 mm in males and 9.47±2.6 mm in females. The sinus index was 2.43±0.37 in males and 2.66±0.32 in females (P<0.000). The frontal sinus index and width were significantly greater in males but the sinus length was not significantly different between males and females (P=0.383). Significant differences were found in stages 2 and 3, and also 4 and 5 in females and 2 and 3, 3 and 4, and 4 and 5 in males. The mean frontal sinus index had a significant correlation with the CVM stage in both groups. CONCLUSION: According to the results, the frontal sinus index cannot be used as a predictor of skeletal maturity.

Radiographic Characteristics of Soft Tissue Calcification on Digital Panoramic Images

Abstract Objective: To assess the prevalence of soft tissue calcifications and their panoramic radiographic characteristics. Material and Methods: This descriptive retrospective study evaluated 2027 panoramic radiographs. The type and location of calcifications and the age and gender of patients were evaluated by two radiologists. Data were analyzed via SPSS and the Chi-square, Fisher's exact and Kappa tests were used to compare the categorical demographic variables among the groups. The confidence interval was set to 95% and p<0.05 was considered statistically significant. Results: The prevalence of calcified stylohyoid ligament was 11.24%. This value was 3.99% for tonsillolith, 1.33% for calcified carotid plaque, 0.69% for antrolith, 0.39% for calcified lymph node, 0.29% for phleboliths, and 0.19% for sialoliths. The prevalence of these conditions had no significant association with gender or age (p=0.102). The prevalence of bilateral calcified stylohyoid ligament, tonsillolith, and a calcified carotid plaque was significantly higher (p<0.001). The most prevalent type of calcified stylohyoid ligament, according to O'Carroll's classification, belonged to types 1, 4, 3 and 2 (p<0.001). The most commonly observed radiographic pattern was multiple, well-defined tonsilloliths (75.3%, p<0.001). Conclusion: The prevalence of soft tissue calcifications on panoramic radiographs was relatively low in this Iranian population. The most calcifications were respectively calcified stylohyoid ligament, tonsillolith, calcified carotid plaque, antrolith, calcified lymph node, phleboliths and sialoliths. Calcified stylohyoid ligament, tonsillolith and calcified carotid plaque were more bilaterally. Thereby panoramic imaging can help in primary assessment, epidemiologic and screening evaluation of these calcifications.

Detecting Important Risk Factors of Survival Time of Lung Cancer Patients Using Censored Quintile Regression.

Objective: Lung cancer is the most frequently diagnosed cancer and the most leading cause of death due to cancer worldwide. This study aimed to use censored quintile regression model to estimate the effect of potential risk factors on survival of lung cancer patients. Methods: In this study we used a dataset of a retrospective cohort study conducted in West Azerbaijan (during 2007 and 2014). Demographic variables included age, and gender and biological variables included Eastern Cooperative Oncology Group, smoking, tumor type, stage, metastasis, and treatment were investigated as risk factors of survival of lung cancer patients by using censored quintile regression. Result: The mean (± standard deviation) age of the 347 lung cancer patients was 63.48 (± 13.55) years. The survival time ranges from 11 to 91. A total of 240 (67.6%) experienced death by the end of the study. The impact of Eastern Cooperative Oncology Group (IV), smoking and treatment were significant for most of quintiles (p<0.05). Stage of cancer and metastasis are the other affective risk factors on the survival of lung cancer patients(p<0.05). It was shown that Eastern Cooperative Oncology, smoking habit and treatment were significantly associated with a shorter time-to-death progression. Conclusion: As censored quintile regression could consider time-varying effects and the interpretation of its regression coefficients are easy it could be an adequate choice for analyzing survival data.

Landmark Prediction of Survival for Breast Cancer Patients: A Case Study in Tehran, Iran.

BACKGROUND: Breast cancer is the first non-cutaneous malignancy in women and the second cause of death due to cancer all over the world. There are situations where researchers are interested in dynamic prediction of survival of patients where traditional models might fail to achieve this goal. We aimed to use a dynamic prediction model in analyzing survival of breast cancer patients. METHODS: We used a data set originates from a retrospective cohort (registry-based) study conducted in 2014 in Tehran, Iran, information of 550 patients were available analyzed. A method of landmarking was utilized for dynamic prediction of survival of the patients. The criteria of time-dependent area under the curve and prediction error curve were used to evaluate the performance of the model. RESULTS: An index of risk score (prognostic index) was calculated according to the available covariates based on Cox proportional hazards. Therefore, hazard of dying for a high-risk patient with breast cancer within the next five years was 2.69 to 3.04 times of that for a low-risk patient. The value of the dynamic C-index was 0.89 using prognostic index as covariate. CONCLUSION: Generally, the landmark model showed promising performance in predicting survival or probability of dying for breast cancer patients in this study in a predefined window. Therefore, this model can be used in other studies as a useful model for investigating the survival of breast cancer patients.

Risk factors for maternal mortality in the west of Iran: a nested case-control study.

OBJECTIVES: With a gradual decline in maternal mortality in recent years in Iran, this study was conducted to identify the remaining risk factors for maternal death. METHODS: This 8-year nested case-control study was conducted in Hamadan Province, in the west of Iran, from April 2006 to March 2014. It included 185 women (37 cases and 148 controls). All maternal deaths that occurred during the study period were considered cases. For every case, four women with a live birth were selected as controls from the same area and date. Conditional logistic regression analysis was performed and the odds ratio (OR) and its 95% confidence interval (CI) were obtained for each risk factor. RESULTS: The majority of cases were aged 20-34 years, died in hospital, and lived in urban areas. The most common causes of death were bleeding, systemic disease, infection, and pre-eclampsia. The OR estimate of maternal death was 8.48 (95% CI=1.26-56.99) for advanced maternal age (≥35 years); 2.10 (95% CI=0.07-65.43) for underweight and 10.99 (95% CI=1.65-73.22) for overweight or obese women compared to those with normal weight; 1.56 (95% CI=1.08-2.25) for every unit increase in gravidity compared to those with one gravidity; 1.73 (95% CI=0.34-8.88) for preterm labors compared to term labors; and 17.54 (95% CI= 2.71-113.42) for women with systemic diseases. CONCLUSIONS: According to our results, advanced maternal age, abnormal body mass index, multiple gravidity, preterm labor, and systemic disease were the main risk factors for maternal death. However, more evidence based on large cohort studies in different settings is required to confirm our results.