Objectives: This study aims to evaluate the efficacy of the rotary instrument XP-endo Finisher for the removal of Ca(OH)2 aided by different irrigation regimens. Methods: Sixteen double-rooted upper premolar human teeth were selected for the study. Thirty-two canals were prepared using a ProTaper Next rotary system up to X3. Then, the canals were filled with Ca(OH)2. The volume of Ca(OH)2 inside the canals was measured by microcomputed tomography (micro-CT). After that, the teeth were randomly allocated into two experimental groups, i.e., A and B (n = 16 canals). In group A, Ca(OH)2 was removed using the master apical file (X3). In group B, Ca(OH)2 was removed using a XP-endo finisher. In half of both groups (n = 8), syringe irrigation (SI) was used, while passive ultrasonic irrigation (PUI) was used for the other half. After removal, the remaining volume of Ca(OH)2 was measured. All data were statistically analyzed using two-way ANOVA with Tukey’s post hoc test. Results: The percentages of remaining Ca(OH)2 in the apical thirds of all canals were significantly higher as compared with the middle and coronal thirds in all groups (p < 0.05). There was no significant difference between different files and techniques (p > 0.05). Clinical Significance: This study presents a new method for the removal of Ca(OH)2 from root canals.

Lysyl oxidases are required for collagen and elastin cross-linking and extracellular matrix maturation including in bone. The lysyl oxidase family consists of lysyl oxidase (LOX) and 4 isoforms (LOXL1-4). Here we investigate whether deletion of LOXL1, which has been linked primarily to elastin maturation, leads to skeletal abnormalities. Left femurs (n = 8), L5 vertebrae (n = 8), and tibiae (n = 8) were analyzed by micro-computed tomography in 13-week-old wild-type (WT) and LOXL1-/- male and female mice. Right femurs (n = 8) were subjected to immunohistochemistry for LOXL1, and histochemical/histology analyses of osteoclasts and growth plates. Sera from all mice were analyzed for bone turnover markers. Results indicate strong expression of LOXL1 in wild-type growth plates in femurs. Significant deterioration of trabecular bone structure in long bones and vertebrae from female was observed but not from male, mutant mice compared with WT. Decreases in BV/TV, Conn.D, trabecular thickness, and number in the femoral distal metaphysis were observed in female, but not in male, mutant mice. Trabecular spacing was increased significantly in femurs of female mutant mice. Findings were similar in trabeculae of L5 vertebrae from female mutant mice. The number of TRAP positive osteoclasts at the trabecular bone surface was increased in female mutant mice compared with WT females, consistent with increased serum RANKL and decreased OPG levels. Analysis of bone turnover markers confirmed increased bone resorption as indicated by significantly elevated CTX-1 in the serum of female LOXL1-/- mice compared to their wild-type counterparts, as well as decreased bone formation as measured by decreased serum levels of PINP. Picrosirius red staining revealed a loss of heterogeneity in collagen organization in female LOXL1-/- mice only, with little to no yellow and orange birefringence. Organization was also impaired in chondrocyte columns in both female and male LOXL1-/- mice, but to a greater extent in females. Data indicate that LOXL1-/- mutant mice develop appendicular and axial skeletal phenotypes characterized by decreased bone volume fraction and compromised trabecular microstructure, predominantly in females.

The action of stem cells is mediated by their paracrine secretions which comprise the secretory profile. Various approaches can be used to modify the secretory profile of stem cells. Creating a hypoxic environment is one method. The present study aims to demonstrate the influence of CoCl2 in generating hypoxic conditions in a dental pulp stem cell (DPSCs) culture, and the effect of this environment on their secretory profile. DPSCs that were isolated from human permanent teeth were characterized and treated with different concentrations of CoCl2 to assess their viability by an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and proliferation by a cell counting kit (CCK)-8 assay. The gene expression level of hypoxia-inducible factor 1-alpha (HIF-1α) was analyzed by quantitative real time polymerase chain reaction (qRT-PCR) to demonstrate a hypoxic environment. Comparative evaluation of the growth factors and cytokines were done by cytometric bead array. Gene expression levels of transcription factors OCT4 and SOX2 were analyzed by qRT-PCR to understand the effect of CoCl2 on stemness in DPSCs. DPSCs were positive for MSC-specific markers. Doses of CoCl2, up to 20 µM, did not negatively affect cell viability; in low doses (5 µM), it promoted cell survival. Treatment with 10 µM of CoCl2 significantly augmented the genetic expression of HIF-1α. Cells treated with 10 µM of CoCl2 showed changes in the levels of growth factors and cytokines produced. It was very evident that CoCl2 also increased the expression of OCT4 and SOX2, which is the modulation of stemness of DPSCs. A CoCl2 treatment-induced hypoxic environment modulates the secretory profile of DPSCs.

BACKGROUND: The occurrence of periodontitis is rather infrequent in children and adolescence and increases with age. We conducted this study because there have been few epidemiological studies on prevalence of periodontitis in children in Saudi Arabia. OBJECTIVE: Determine the prevalence of periodontitis in high school children in Saudi Arabia. DESIGN: Cross-sectional, using cluster and multistage sampling. SETTING: High school children in Saudi Arabia. PARTICIPANTS AND METHODS: Periodontal examinations were conducted on a randomized sample of high school children between the ages 15 to 19 in Saudi Arabia. The study spanned from September 2012 to January 2016. Clinical examinations included measurements of the probing depth (PD) percentage of PD ≥4 mm per patient. MAIN OUTCOME MEASURES: The prevalence of periodontitis (PD ≥4 mm and CAL ≥1 mm), the mean percentage PD ≥4 mm, the mean percentage CAL ≥1 mm, plaque index (PI) and gingival index (GI). SAMPLE SIZE: 2435 high school students. RESULTS: Of 2435 high school children in the sample, 209 students (8.6%) had periodontitis. The mean (standard deviation) for the PD was 0.59 (0.17) mm. Differences in percentage PD ≥4 mm and CAL ≥1 mm were greater in students with periodontitis ( P <.001). The prevalence of periodontitis was higher among non-Saudis, students who did not brush their teeth and did not visit their dentist regularly. In the bivariate analysis, periodontitis was positively associated with GI, PI, number of teeth extracted, mean percentage PD ≥4 mm, and mean PD. However, in the multivariate analysis, tooth brushing was the main factor protective against periodontitis (odds ratio: 0.62, 95% CI 0.42-0.92, P =.017). CONCLUSION: Periodontitis prevalence was high compared with Western countries in a nationally representative sample of high school students in Saudi Arabia. LIMITATIONS: Partial mouth study design, which may underestimate the disease prevalence. CONFLICT OF INTEREST: None.