Calcium hydroxide regulates transcription of the bone sialoprotein gene via a calcium-sensing receptor in osteoblast-like ROS 17/2.8 cells.

Bone sialoprotein (BSP) is a glycoprotein associated with mineralized tissues. In this study, we investigated the regulation of Bsp transcription by calcium hydroxide [Ca(OH)2 ] in rat osteosarcoma-derived osteoblast-like ROS 17/2.8 cells and stromal bone marrow cells. Application of Ca(OH)2 (0.4 mM) increased the levels of runt-related transcription factor 2 (Runx2) and BspmRNAs at 3 and 6 h and the level of BSP protein at 12 h. Transient transfection analyses were performed using chimeric constructs encompassing different regions of the rat Bsp gene promoter ligated to a luciferase reporter gene. It was found that Ca(OH)2 increased the luciferase activities of the pLUC3 and pLUC4 constructs. Introduction of 2-bp mutations to the luciferase construct showed that the effects of Ca(OH)2 were mediated by cAMP response-element (CRE) and fibroblast growth factor 2 (FGF2) response element (FRE). Luciferase activities induced by Ca(OH)2 were blocked by protein kinase C (PKC), protein kinase A (PKA), phosphoinositide-3-kinase (PI3-K), and extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitors and by calcium-sensing receptor (CASR) antagonists. Gel-shift analyses showed that Ca(OH)2 increased binding of nuclear protein to CRE and FRE. Dexamethasone-induced mineralization in stromal bone marrow cells was abrogated by CASR antagonists. These studies demonstrate that Ca(OH)2 regulates Bsp transcription via the CASR by targeting CRE and FRE in the rat Bsp gene promoter.

Autotransplantation of mature and immature third molars in 23 Chinese patients: a clinical and radiological follow-up study.

BACKGROUND: We investigated the clinical and radiographic outcomes of autotransplanted teeth over a follow-up period of 2 to 8 years, and summarize the findings of other relevant studies with regard to the primary factors that influence a good prognosis in such patients. METHODS: Twenty-three patients (6 men, 17 women) who attended Tanggu Stomatological Hospital, Tianjin, China, from 2008 through 2013, were included in the study. These patients presented with a variety of dental problems, including tooth loss, residual crowns, missing first or second molars, dental trauma, tooth fracture, and unrestored teeth. A total of 26 third molars, including 2 immature molars, were autotransplanted in these patients. The success rate of autotransplantation was assessed on the basis of clinical and radiographic outcomes after follow-up periods ranging from 2 to 8 years. RESULTS: Clinical examination revealed stability of all 26 transplanted teeth, with satisfactory masticatory function and no patient discomfort. Radiographic examination revealed normal periapical tissues and an intact lamina dura surrounding the tooth root, indicating adequate healing of periodontal tissues. CONCLUSIONS: Autotransplantation achieved good results in the Chinese sample population investigated, and was associated with an excellent prognosis. Rigorous case selection, adequate protection of the periodontal ligament, and proper oral hygiene contribute significantly to the long-term success of the procedure.

Preparation a High-Performance of Gangue-Based Geopolymer Backfill Material: Recipes Optimization Using the Taguchi Method.

The strip filling method in underground reservoir needs high strength to achieve the requirements of water storage. In order to address the challenges associated with costly and weak filling materials, this study aimed to develop an economically efficient and high-strength gangue-based geopolymer backfill material (GBGBM). To achieve this, the Taguchi method was employed to design a series of 25 experiments, each consisting of four factors and five levels. This study focused on investigating the effects of different gangue gradation levels, sand ratios, water binder ratios (w/b), and aggregate binder ratios (a/b) on the working characteristics and unconfined compressive strength (UCS) of the GBGBM. The optimal combination of the GBGBM was determined by employing a signal-to-noise ratio (S/N)-based extreme difference and variance analysis. The results revealed that the w/b ratio exerted the most substantial influence on both the slump and UCS. Specifically, when employing a gradation of 50%, a sand ratio of 55%, an a/b ratio of 2.5, and a w/b ratio of 0.64, the slump measured 251.2 mm, the UCS at 3d reached 5.27 MPa, and the UCS at 28d amounted to 17.65 MPa. These findings indicated a remarkable improvement in early UCS by 131.14% and the late UCS by 49.45% compared to gangue-based cement backfill material (GBCBM). Additionally, this study examined the hydration products and microstructures of both GBGBM and GBCBM using X-ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) analyses. Significantly, the GBGBM exhibited notable advantages over the GBCBM, including a 78.16% reduction in CO2 emissions, a 73.45% decrease in energy consumption, and a 24.82% reduction in cost. These findings underscore the potential of GBGBM as a sustainable and cost-effective alternative to GBCBM.

Study of Mechanical Properties and Durability of Alkali-Activated Coal Gangue-Slag Concrete.

Herein, a new geopolymer is recognized as a potential alternative cementing material of ordinary Portland cement (OPC), which is used for reducing carbon emissions and efficiently recycling the waste. Therefore this paper mainly studied the alkali-activated coal gangue-slag concrete (ACSC) was prepared by using the coal gangue-slag and Na2SiO3 and NaOH complex activator. The ratio of coal gangue (calcined and uncalcined) coarse aggregate replacing the gravel was 0%, 30%, 50%, 70%, and 100%. The water and salt freeze-thaw resistance, compressive strength, chloride permeation, microstructure, performance mechanism, inner freeze-thaw damage distribution, and mechanics models of ACSC were investigated. Results show that ACSC displayed excellent early age compressive strength, and the compact degree and uniformity of structure were better compared with the ordinary Portland cement (OPC) when the coal gangue replacement rate was less than 50%. The ACSC demonstrated the best chloride penetration resistance under 30% uncalcined coal gangue content, which was less than 27.75% lower than that of using OPC. At the same number cycles, especially in the salt freezing, the calcined coal gangue had lowered advantages of improving resistance freeze-thaw damage resistance. Water and salt accumulative freeze-thaw damage mechanics models of ACSC were established by using the relative dynamic elasticity modulus. The exponential function model was superior to the power function model with better precision and relativity, and the models accurately reflected the freeze-thaw damage effect.

A preliminary study on potential association between psychopathological status and rhythmic masticatory muscle activity of young patients with sleep bruxism in Tianjin China.

OBJECTIVES: The aim of this cross-sectional study was to assess the psychological status of patients with bruxism and to explore the potential relationship between psychological status and rhythmic masticatory muscle activity (RMMA), since the basic manifestation of sleep bruxism is RMMA. METHODS: Twenty-five patients (nine males, 16 females, and mean age 27.84 ± 5.60) who self-reported having SB and 25 normal subjects were randomly recruited. Fifty subjects filled out the Symptom Checklist-90 (SCL-90) to assess their psychopathological status. SB was diagnosed by polysomnography (PSG), and RMMA was recorded based on the results of PSG. RESULTS: In this study we detected 15.89 ± 4.23 RMMA episodes per hour in normal subjects, whereas 41.23 ± 16.78 RMMA episodes per hour were recorded in patients with SB, which was nearly three times of the former group with statistical significance (P = 0.001). Paired t-test revealed significant differences between SB patients and normal subjects in any of the SCL-90 subscales (P = 0.001). Regarding total psychopathological scores, 10 of the 25 SB patients endorsed scores higher than 160, and the positive rate was 40%. In addition, obsessive-compulsive behavior, interpersonal sensitivity, depression, anxiety, paranoid ideation and psychoticism were all statistically associated with RMMA (P < 0.05). CONCLUSION: Within the limitations of the study, we found that patients with sleep bruxism tend to have poor psychological status, and obsessive-compulsive behavior, interpersonal sensitivity, depression, anxiety, paranoid ideation and psychoticism are related to onset of SB.

The Extent of the Crack on Artificial Simulation Models with CBCT and Periapical Radiography.

BACKGROUND: The aim of this study was to investigate the extent of the crack of a cracked tooth on an artificial simulation model with Periapical Radiography (PR) and cone beam computed tomography (CBCT) in vitro, providing the basis for early diagnosis and an appropriate treatment plan. METHODS: Forty-four teeth with different extents of artificial cracks, created by exposure to liquid nitrogen after hot water at 100°C, were collected. They were subjected to PR and CBCT. Micro-computed tomography (micro-CT) examination, regarded as a relatively more accurate measurement than others, was used to measure and record the crack depth. Three observers, an endodontic graduate student, an experienced endodontist, and an experienced radiologist, examined the PR and CBCT results independently, and the presence or absence of cracks with PR and CBCT were respectively recorded. The external consistency ICC with 95% confidence interval (95% CI) was used to analyze the consistency among the graduate student, endodontist, and radiologist; ROC curves were used for the analysis of diagnostic performance of both radiographic modalities for tooth cracks with crack depth. RESULTS: For the interpretation of the PR results, there were statistically significant differences among the three different observers (P < 0.001), and the interpretation of the CBCT results (P < 0.001). In the group of results read by the graduate student, the sensitivity of diagnosis with CBCT and PR was 77.27% and 22.73%, respectively (P < 0.001). In the group of results read by the endodontist, the sensitivity of diagnosis with CBCT and PR was 81.81% and 8.19%, respectively (P < 0.001). In the group of results read by the radiologist, the sensitivity of diagnosis with CBCT and PR was 88.64% and 11.36%, respectively (P < 0.001). As for CBCT diagnosis, the critical value for the graduate, endodontist, and radiologist was 3.20 mm, 2.06 mm, and 1.24 mm, respectively. For the PR diagnosis, the critical value for the graduate, endodontist, and radiologist was 6.12 mm, 6.94 mm, and 6.94 mm, respectively. CONCLUSIONS: Within the limitations of this study, on an artificial simulation model of cracked teeth for early diagnosis, we recommend that it would be better for a cracked tooth to be diagnosed by a radiologist with CBCT than PR, CBCT with a minimum depth of 1.24 mm.

Cracked Teeth and Poor Oral Masticatory Habits: A Matched Case-control Study in China.

INTRODUCTION: Previous studies have suggested that masticatory forces are associated with cracked teeth, but it is not clear which specific poor oral masticatory habits may be more likely to cause cracks. The aim of this study was to quantitatively assess risk factors for cracked teeth among poor oral masticatory habits and create a model for individualized risk predictions. METHODS: We enrolled 35 patients with cracked teeth matched to 70 controls without cracked teeth by age, sex, position of the affected tooth, presence/absence of systemic disease, and diagnosis of symptomatic irreversible pulpitis from the Stomatology Hospital of Tianjin Medical University, Tianjin, China. Odds ratios (ORs) were calculated using conditional logistic regression analysis. RESULTS: Thermal cycling eating habits (OR = 3.296; 95% confidence interval [CI], 1.684-6.450), eating coarse foods (OR = 2.727; 95% CI, 1.340-5.548), chewing on hard objects (OR = 2.087; 95% CI, 1.041-4.182), and unilateral mastication (OR = 2.472; 95% CI, 1.255-4.869) were independent risk factors for cracked teeth. The corresponding risk scores were 2.182, 1.691, 1.467, and 1.589, respectively. The area under the receiver operating characteristic curve and its 95% CI were 0.920 (0.868-0.973); the sensitivity and specificity were 0.943 and 0.800, respectively. CONCLUSIONS: Thermal cycling eating habits were strongly associated with cracked teeth, whereas eating coarse foods, chewing on hard objects, and unilateral mastication were also independent risk factors for cracked teeth. These findings yield insights into ways to promote the prevention of risky behaviors for cracked teeth.