Novel beagle model of gastric local fibrotic target lesions for the evaluation and training of endoscopic techniques.

BACKGROUND: Novel endoscopic techniques used in the treatment of gastric lesions with local submucosal fibrosis need preclinical evaluation and training due to safety limitations. Therefore, the purpose of our study was to establish an animal model of gastric local fibrotic target lesions and assess its feasibility in the evaluation and training of endoscopic techniques. METHODS: In six experimental beagles, a 50% glucose solution was injected into three submucosal areas of the fundus, body, and antrum of the stomach to create gastric local fibrotic target lesions (experimental group). On post-injection day (PID) 7, the injection sites were assessed endoscopically to confirm the presence of submucosal fibrosis formation, and the dental floss clip traction assisted endoscopic submucosal dissection (DFC-ESD) procedure was performed on the gastric local fibrotic target lesions to confirm its feasibility after endoscopic observation. The normal gastric mucosa of six control beagles underwent the same procedure (control group). All the resected specimens were evaluated by histological examination. RESULTS: All 12 beagles survived without postoperative adverse events. On PID 7, 16 ulcer changes were observed at the injection sites (16/18) under the endoscope, and endoscopic ultrasonography confirmed the local submucosal fibrosis formation in all ulcer lesions. The subsequent DFC-ESD was successfully performed on the 32 gastric target lesions, and the mean submucosal dissection time in the ulcer lesions was greater than that in the normal gastric mucosa (15.3 ± 5.6 vs. 6.8 ± 0.8 min; P < 0.001). There was no difference in rates of en bloc resection, severe hemorrhage, or perforation between the two groups. Histological analysis of the ulcer lesions showed the absence of epithelial or muscularis mucosae and extensive submucosal fibrous tissue proliferations compared with normal gastric mucosa. Overall, endoscopists had high satisfaction with the realism and feasibility of the animal model. CONCLUSION: We developed a novel animal model of gastric local fibrotic target lesions to simulate difficult clinical situations, which strongly appeared to be suitable for the preclinical evaluation and learning of advanced endoscopic techniques.

Tumor Tropic Delivery of Hyaluronic Acid-Poly (D,L-lactide-co-glycolide) Polymeric Micelles Using Mesenchymal Stem Cells for Glioma Therapy.

Tumor penetration and the accumulation of nanomedicines are crucial challenges in solid tumor therapy. By taking advantage of the MSC tumor-tropic property, we developed a mesenchymal stem cell (MSC)-based drug delivery system in which paclitaxel (PTX)-encapsulating hyaluronic acid-poly (D,L-lactide-co-glycolide) polymeric micelles (PTX/HA-PLGA micelles) were loaded for glioma therapy. The results indicated that CD44 overexpressed on the surface of both MSCs and tumor cells not only improved PTX/HA-PLGA micelle loading in MSCs, but also promoted the drug transfer between MSCs and adjacent cancer cells. It was hypothesized that CD44-mediated transcytosis played a crucial role and allowed deep glioma penetration depending on sequential intra-intercellular delivery via endocytosis-exocytosis. MSC-micelles were able to infiltrate from normal brain parenchyma towards contralateral tumors and led to the eradication of glioma. The survival of orthotopic glioma-bearing rats was significantly extended. In conclusion, the MSC-based delivery of HA-PLGA micelles is a potential strategy for tumor-targeting drug delivery.

Carious status and supragingival plaque microbiota in hemodialysis patients.

OBJECTIVE: The aim of this study was to evaluate the carious status and the microbial profiles of supragingival plaque in patients with chronic kidney disease undergoing hemodialysis. METHODS: This study included 30 patients with chronic kidney disease undergoing hemodialysis as well as 30 control subjects. Dental examination was performed and the decayed-missing-filled-teeth was recorded. Supragingival plaque was taken and analyzed using 16S rRNA gene amplicon by Illumina MiSeq sequencing to detect microbial composition and community diversity and structure. RESULTS: The level of decayed-missing-filled-teeth was higher in the hemodialysis group than that in the control group. Microbial analysis showed a decrease in α diversity and a increase in relative abundance and prevalence of many acidogenic and aciduric caries related species in the supragingival plaque samples of the hemodialysis patients, including Streptococcus mutans, Lactobacillus salivarius, Lactobacillus fermentum, Lactobacillus vaginalis, Scardovia wiggsiae F0424, and Actinomyces naeslundii. CONCLUSION: Our results suggested that the hemodialysis patients were more susceptible to caries. More attentions for caries prevention and treatment should be paid to improve their life quality, and even to reduce their cardiovascular events and survival.

Urea Rinse effectively Neutralises Sucrose-induced Decrease in Plaque pH.

OBJECTIVES: To investigate the neutralising effects of subsequent urea rinse on sucrose-induced decrease in plaque pH with interdental plaque pH telemetry. METHOD: Six participants wearing partial lower prostheses which incorporated a miniature glass pH electrode were included. After 5 or 6 days of plaque accumulation on the tip of the electrode, the subjects rinsed with a 15 ml 10% sucrose solution, followed by no subsequent rinsing or rinsing with either 15 ml of water, 0.25%, 0.50% or 1.00% urea solution, for 2 min. The plaque pH was continuously recorded for 120 min. RESULTS: Without subsequent rinsing, the plaque pH decreased at 10 min to 4.39 and stayed below the critical pH of 5.7 for 80 min following a sucrose rinse. Subsequent water rinse showed little effects on the sucrose-induced decrease in plaque pH, whereas subsequent urea rinses all immediately and effectively neutralised sucrose-induced decrease in plaque pH, and remained above the critical pH of 5.7 until the end of data collection. CONCLUSION: Urea rinse could effectively counteract the pH fall following sucrose administration. These results strongly suggested that the regular use of low-concentration urea rinse after carbohydrate consumption may help prevent caries.

Inhibition of acidogenicity in dental plaque by sodium fluoride solution after sucrose rinse.

OBJECTIVE: To evaluate the effect of sodium fluoride rinse on sucrose-induced decrease in plaque pH with interdental plaque pH telemetry. METHODS: Six participants wearing partial lower prostheses incorporating a miniature glass pH electrode were included. The measurement of plaque pH was performed after 6 days of plaque accumulation. Three experiments were performed to test the effects of fluoride administered before (experiment I) or 10 min after (experiment II) and 25 min after (experiment III) a sucrose rinse. In experiment I, the subjects rinsed with 0.05% NaF solution before rinsing with 10% sucrose to examine the effect of fluoride on the sucrose-induced pH drop. In experiment II, the subjects first rinsed with 10% sucrose and then followed no subsequent rinsing or rinsing with tap water 10 min after sucrose expectoration, or 0.05%, 0.02% or 0.01% NaF solution for 2 min. In experiment III, the subjects first rinsed with 10% sucrose and then 25 min after sucrose expectoration, they rinsed with 0.05% NaF for 2 min. The plaque pH was continuously recorded for about 120 min. RESULTS: Without any subsequent rinses, the plaque pH decreased at 10 min to 4.36 and stayed below the critical pH 5.7 for about 85 min after the sucrose rinse. Subsequent water rinses showed little effect on the sucrose-induced decrease in plaque pH. Pretreatment of 0.05% NaF solution showed no effect on the subsequent sucrose-induced pH drop. Subsequent rinses with NaF solutions at 10 min after the sucrose rinse inhibited the sucrose-induced pH drop in a dose-dependent manner. Subsequent rinses with NaF solutions after the sucrose rinse also significantly reduced the time below pH 5.7 and the area of plaque pH curve under 5.7 (AUC5.7). Furthermore, the AUC5.7 value (3.99) of 0.05% NaF rinse at 10 min after the sucrose rinse was much smaller than that (57.01) of 0.05% NaF rinse at 25 min after the sucrose rinse. CONCLUSION: Rinsing with 0.05% fluoride after carbohydrate consumption effectively reduced the acidogenicity of the plaque and could enhance the anticaries functions of fluoride.

Dental plaque pH recovery effect of arginine bicarbonate rinse in vivo.

OBJECTIVE: To investigate the neutralising effects of subsequent arginine bicarbonate rinse on sucrose-induced decrease in plaque pH with interdental plaque pH telemetry. METHODS: Six participants wearing partial lower prostheses incorporating a miniature glass pH electrode were included. After 5 or 6 days of plaque accumulation on the tip of the electrode, the subjects rinsed with a 15 ml 10% sucrose solution, followed no subsequent rinsing or rinsing with 15 ml of water, or 85 mmol/L NaHCO3, or 0.5%, 1% or 2% arginine bicarbonate for 2 min. The plaque pH was continuously recorded for 120 min. RESULTS: Without a subsequent rinse, the plaque pH decreased at 10 min to 4.38 and stayed below the critical 5.7 for 83 min after sucrose rinse. Subsequent water rinse showed little effects on the sucrose-induced decrease in plaque pH and NaHCO3 induced only an instantaneous pH rise, whereas subsequent arginine bicarbonate rinses all immediately and effectively neutralised the sucrose-induced decrease in plaque pH. CONCLUSION: These results strongly suggested that regular use of an arginine bicarbonate rinse after carbohydrate consumption could help prevent caries.

[Effect of carbamide peroxide bleaching agents on micro-leakage of composite resin interface in vitro].

OBJECTIVE: To evaluate the effect of carbamide peroxide (CP) bleaching agents at different concentrations and with different carriers on the micro-leakage of composite resin interface. METHODS: Class V cavity (2 mm in diameter and 2 mm in depth) preparations were made at the enamelo-cemental junction on the buccal and lingual surfaces of 35 extracted human premolars. The cavities were filled with hybrid composite resin. The teeth were stored for 24 h in distilled water at 37 degrees celsius; before thermocyling for 500 times between 5 and 55 degrees celsius;. The teeth were then randomly assigned into 7 groups, and in groups 1-6, the bleaching gels containing 10% or 20% of CP were applied on the buccal and lingual surface of the teeth for two weeks (6-8 h/day, 37 degrees celsius;, 100% relative humidity) using Carbopol, PVP or Poloxamer as the thickening carriers, respectively. The seventh group served as the control without bleaching treatment. Nail polish was applied to the surface of the tooth, and all the teeth were immersed in ammoniacal silver nitrate solution followed by developing solution. The teeth were finally sectioned through the midline of the restoration and observed under stereomicroscope. SEM micrographs were also made to observe the interface. RESULTS: With the same bleaching agent, the micro-leakage in the gingival wall was slightly greater than in the occlusive wall, but the difference was not significant. Only 20% CP with Poloxamer as the thickening agent significantly increased the leakage of dentine-resin composite interface, and 10% and 20% CP with Carbopol or PVP as the thickening agents and 10% CP with Poloxamer produced minimal effects on filling the micro-leakage. CONCLUSION: Thickening carriers and the concentration of CP (20% or below) have no significant effect on micro-leakage of composite resin.

[A 3-dimensional finite element analysis of displacement of maxillary first molar on mesial movement in lingual orthodontics].

PURPOSE: To analyze the displacement of maxillary first molar on mesial movement by lingual technique with the finite element method,and compare with that by labial technique. METHODS: The finite element model was built using the advanced 3-dimensional laser scanning, comprising a maxillary first molar, periodontal ligament, alveolar bone, and a lingual or buccal tube. Different kinds of loads were applied at a point of the lingual or buccal tube separately. By finite element method,the displacement of maxillary first molar was calculated and analyzed. RESULTS: When the mesial force was applied to the maxillary first molar,the tooth was tipped mesially, rotated distally and lingually by lingual technique. By the labial technique,the tooth was tipped mesially, rotated distally and buccally. The degree of tipping and rotation by labial technique was bigger than that by lingual technique. By labial technique, Mt/F=8.1:1,Mr/F=8:1. By lingual technique, Mt/F=6.9:1,Mr/F=7.1:1. When the tooth moved bodily,the displacement of lingual technique was larger than that by labial technique. CONCLUSIONS: When the maxillary first molar moved bodily toward mesial direction, lingual orthodontics is more efficient than labial orthodontics.

[Evaluation of acid diffusion and fluoride selective electrode to measure the total fluoride in toothpastes].

OBJECTIVE: To evaluate the reliability of a method of measuring the total fluoride in fluoride-containing toothpastes with acid diffusion and fluoride selective electrode. METHODS: Four brands of commercially available non-fluoride toothpastes and fluoride-containing toothpastes were sampled. Fluoride was extracted from the toothpastes in 2 mol/L HC10(4) at room temperature overnight and then subjected to the measurement with fluoride electrode. RESULTS: Fluoride recovery of the non-fluoride toothpastes containing calcium as abrasive by this method was 99.5%-100.5%, more than 94% of total fluoride was measured from the marketed fluoride toothpastes, and the variation coefficient of this method was less than 1.54%. While the abrasive was silicon, the fluoride recovery of the non-fluoride toothpastes was 83.4%, and 89.7% of total fluoride was measured from the marketed fluoride-containing toothpastes. CONCLUSION: The amount of total fluoride in the calcium containing toothpaste can be detected simply and accurately measured by acid diffusion and fluoride selective electrode.

[Root canal therapy opportunity in replanted teeth due to injury.].

PURPOSE: To investigate the opportunity of different root canal therapies in replantation of tooth due to injury. METHODS: 49 cases with teeth luxation were randomly divided into three groups. In group A, the pulp was removed before replanted, and calcium hydroxide was filled in root canals and condensated routinely after half a year. In group B, the pulp was removed one week after being replanted. In group C, the pulp was removed until pulp disease. RESULTS: The effect of group A(81.25%) and B (94.44%) was better than group C (53.33%), P<0.05. And the effect of group A and B was similar. CONCLUSION: It's an ideal method to replant luxated tooth within 3 hours with removal of pulp tissue, root canal filling with calcium hydroxide one week after replantation of tooth and condensated routine root canal therapy after half a year.