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Objective Studies have shown that low concentrations of nicotine can promote neovascularization and promote wound healing.This article aimed to investigate the influence of low concentration collagen membrane slow-release system on the hard palate trauma of rats.Methods Using poly(lactic acid-co-glycolic acid) (PLGA) copolymer as carrier materials, low concentration nicotine sustained-release particles were prepared by emulsion evaporation method (w/o/w), using collagen membrane as the brace and establish a low concentration collagen membrane system.48 Wistar rats were divided into experimental group and blank group, 3 mm diameter circular wound was made in the forepart palate.Low concentration of nicotine collagen membrane sustained-release particle system and blank collagen membrane (control) were sutured on the wound with 6-0 absorbable thread.Then, observed the wound healing of 0, 3, 7, 10 days and compared the healing differences between each groups.Results Under the electron microscope, the nicotine sustained-release particles were circular, similar size with rough surface, the average diameter were 3.0±0.2μm, the encapsulation efficiency and drug loading rate was 50.2% and 4.12% respectively.In vitro, nicotine sustained-release particles released much more nicotine on the first day, less on the second day, tends to stable and fluctuate within a certain range from the third day on, and declined sharply after about 10 days, nicotine concentration from 3rd to 10th day was fluctuate within 10-5-10-4mol/L.Postoperative wound healing, no significant difference in 3 days(P>0.05), after 7 days, the wound healing of experimental group significantly greater compared with the control (P=0.015).The wound was healed in 10 days after operative, there was no significant difference between two groups(P>0.05).The epithelial proliferation in the experimental group was significantly greater than that in the blank group, there were many fibroblasts, inflammatory cells and new capillaries, the epithelial process is short, the submucosa is loose, and a large number of collagen fibers are produced.The lamina propria is closely connected with the periosteum, and the wound is healed Conclusion Low concentration of nicotine sustained-release particles collagen membrane system may promote wound healing in the hard palate mucosa of rats.
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Objective Streptococcus sanguis is a possible candidate bacterium for the caries replacement therapy, which has no advantages in the acidic environment.The aim of the study was to construct acid-resistant strains of Streptococcus sanguis, determine its acid tolerance, and explore the mechanism of its antagonism against Sterptococcus mutans.Methods By gradually reducing the pH value of the medium, we constructed acid-resistant strains of Streptococcus sanguis, observed their growth and measured their acid tolerance according to their survival rate against lethal pH.We evaluated the competitive relationship between Streptococcus sanguis and Streptococcus mutans by plate experiment and detected the changes of related acid resistance genes by real-time quantitative PCR.Results The growth of Streptococcus sanguis and its acid-resistant strains were limited by the pH value, and that of Streptococcus sanguis was better in either acidic or normal environment.The lethal pH value of Streptococcus sanguis was 3.6, that of its acid-resistant strains was 2.3, and the survival rate of the acid-resistant strains was 66.59% in the pH 3.6 environment.In comparison, the lethal pH value of Streptococcus mutans was 2.5, that of its acid-resistant strains was 2.1, and the survival rate of the acid-resistant strains was 2.55% in the pH 2.5 environment.In the presence of chloramphenicol, the acid-resistant strains could not survive in the original lethal pH.In the sub-lethal pH environment, the expressions of the acid resistance-related genes Groel and Dnak in the acid-resistant strains were significantly up-regulated as compared with those in the original Streptococcus sanguis (P<0.05).Conclusion Streptococcus sanguis has an acid adaptability and can enhance acid resistance in the sub-lethal pH environment.Acid-resistant Streptococcus sanguis in the replacement therapy may provide some new ideas for the treatment of dental caries.
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Objective Antimicrobial peptides are the focus of recent research in oral microbiology .This study aimed to eval-uate the activity of a novel antimicrobial peptide pm 11 against oral microorganisms and its action mechanisms . Methods We ana-lyzed the effect of pm11 on oral microorganisms and determined its antimicrobial activity in the saliva environment by measuring its min -imal inhibitory concentration (MIC), minimal bactericide concentration (MBC), and bactericidal kinetics.We observed its bacteri-cidal activity on the biofilms of streptococcus mutans by confocal laser scanning microscopy (CLSM) and the structural changes in the bacterial membrane by scanning electron microscopy (SEM). Results The antimicrobial activity of pm11 varied greatly against dif-ferent oral microorganisms , with its MIC values ranging from 2 μg/mL to 256 μg/mL and its MBC values from 2 μg/mL to >256μg/mL.The bactericidal kinetics showed a decreasing survival rate of bacteria with the lengthening of the intervention time .The inhib-itory-zone diameters exhibited no significant indifference between the water solution and the sterile saliva solution .CLSM revealed an increased number of dead bacteria in the pm 11-treated biofilms , while SEM manifested obvious changes in the shape of the bacteria membrane treated with pm11. Conclusion Our findings suggest that pm11 has a broad spectrum of antimicrobial activities on oral mi-croorganisms and a potential value of clinical application .
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[Abstract ] Objective More and more researches demonstrate that epithelial-mesenchymal transition(EMT) is highly rele-vant to cancer metastasis , tissue fibrosis and skin wound healing , but its role in the wound healing of oral mucosa still needs further ex-ploration.This study was designed to discuss the effects of EMT on the wound healing of lingual mucous membrane in rats . Methods A 3mm-diameter circular defect was made on the mucosa of lingual dorsum in 8-week-old Wistar rats.The rats were put to death at day 0, 1, 2, 3, 4 and 8 after operation.We observed tissue healing process by HE staining and used immunohistochemical fluorescence to detect the expressions of EMT-related protein E-cadherin(E-cad), Vimentin and Fibroblast specific proteins (FSP1) in lingual mucous membrane during wound healing . Results The expressions of E-cad at the edge of the wound in the lingual mucous membrane of rats at day 2 and 4 after operation were less than those at day 0 and 1 after operation , while interstitial cell specific protein Vimentin and FSP1 were positively expressed in the epidermal basal layer .The wound of lingual mucous membrane healed completely at day 8 after operation , and E-cad expression was close to that at day 0 after operation .A small amount of Vimentin and FSP 1 expressed in the epi-thelial basal layer . Conclusion E-cad, Vimentin, FSP1 are involved in the wound healing process of lingual mucous membrane . During the wound healing in the tongue mucous membrane of rats , some epithelial cells gain the feature of mesenchymal cells in the process of migration to wound centre .EMT has played an important role during wound healing of lingual mucous membrane in rats .
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BACKGROUND:Low concentration of nicotine promotes the angiogenesis and facilitates the healing of skin wounds. However, the role of low concentration of nicotine on the repair of maxil ofacial soft tissue trauma especial y oral mucosa stil remains unclear OBJECTIVE:To evaluate the effect of low concentration of nicotine on mucosa defect repair of rat hard palate. METHODS:A circular soft tissue defect at 3 mm diameter was produced in the centre of hard palate of 65 Wistar rats. After the operation, animals were randomly divided into low concentration of nicotine with gel group, gel group and control group. Rats were sacrificed at 3, 7, 10 and 14 days post-surgery. The wound healing was detected with hematoxylin-eosin staining and the difference of wound healing in different groups was compared with gross observation and image measurement. RESULTS AND CONCLUSION:There was no significant difference in the wound healing in different groups on day 3 post-surgery. On days 7 and 10, the group of low concentrations of nicotine with gel was faster than gel group and control group (P<0.05);the wounds were completely healed on day 14, with no significant difference among the groups. Low concentrations of nicotine may promote the mucosa defects repair of rat hard palate.
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Objective: To study the treatment methodology of postoperative disostosis of maxilla in the patients with cleft palate by orthognathia. Methods: 10 cases (6 males and 4 females) of postoperative dysostois of maxilla in the patients with cleft palate were treated by orthognathia. Operation manners and orthodontic treatment were determined by orthodontists and surgeons before treatment. Orthodontic treatment included upper arch expansion, teeth alignment, leveling the Spee's curve etc. Operation on single jaw or double jaw, or extraction of one anterior tooth to decrease lower dlental arch and to coordinate with the upper jaw forward was conducted according to individual situations. Adjustment of intercuspids relation was conducted after operation. Results: In all the 10 cases discrepancy of upper and lower jaws were resolved, profiles of the faces were improved significantly, dental arch symmetry, physiological overjet and overbite were achieved. Conclusion: Orthognathia is effective in the treatment of postoperative dysostosis in the patients with cleft palate.
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Objectives:To investigate the relationship between calcitonin gene-related peptide(CGRP) in rat dental pulp and tooth movement.Methods:The first maxillary molars in 36 SD rats were moved mesially by orthodontic force,18 were examined 3,7 and 14 day after application of the appliance whereas another 18 rats were observed 7,14 and 28 days after removal of the appliance respectively.6 control rats were without treatment.Then,CGRP immunoreactivity was demonstrated by indirect immunoflurescence on frozen sections of dental pulp samples.Results:3,7 and 14 days after application of orthodontic force, the CGRP containing nurve fiber counts in each pulp were 17.57?4.42,24.04?3.55 and 21?4.11 respectively,those in the control pulps were 8.03?4.49. 7,14 and 28 days after removal of the appliance, the counts were 19.23?5.23,18.23?5.08 and 8.12?5.01 respectively.Conclusions:CGRP immunoreactive nerve fibres may take an active part in tissue responses in pulp tissues during experiment tooth movement.