[An in vitro experiment on the stability and irritant of hypochlorous acid in oral cavity].

PURPOSE: To study the stability of physicochemical properties and sterilizing effect about two commercially available hypochlorous acid (HClO) products under simulated clinical conditions, and to evaluate the compatibility of HClO on soft and hard tissues and cells in oral cavity. METHODS: Samples of HClO solution with different production processes were prepared, to detect the changes of physicochemical indexes of each sample over time under simulated clinical conditions (shielded from light at 20-25 ℃, open the cover for 5 minutes every day), including free available chlorine, oxidation-reduction potential and pH. Through suspension quantitative germicidal test, the antibiosis-concentration curve of HClO solution was made, so as to calibrate the change of antibacterial ability of disinfectant with the decrease of available chlorine content during storage. Pulp, tongue and dentine were immersed in PBS, 100 ppm HClO, 200 ppm HClO and 3% NaClO. The influence on soft and hard tissues was evaluated by weighing method and microhardness test. The toxic effects of HClO, NaClO and their 10-fold diluent on human gingival fibroblasts were determined by CCK-8 cytotoxicity assay. GraphPad PRIS 8.0 software was used to analyze the data. RESULTS: Under simulated conditions, the free available chlorine (FAC) of HClO solution decayed with time, and the attenuation degree was less than 20 ppm within 1 month. The bactericidal effect of each HClO sample was still higher than 5log after concentration decay. There was no obvious dissolution and destruction to soft and hard tissues for HClO(P＞0.05). The cell viability of HClO to human gingival fibroblast cells (HGFC) was greater than 80%, which was much higher than 3% NaClO (P＜0.001). CONCLUSIONS: The bactericidal effect and stability of HClO solution can meet clinical needs, which has low cytotoxicity and good histocompatibility. It is expected to become a safe and efficient disinfection product in the field of living pulp preservation and dental pulp regeneration.

[Intramuscular type of nodular fasciitis: a report of 3 cases and review of literature].

PURPOSE: To retrospectively analyze the clinical characteristics of impacted supernumerary teeth in 115 patients. METHODS: One hundred and fifteen patients with im-pacted supernumerary teeth who were admitted to the Department of Oral and Max-illofacial Surgery of Hefei Stomatological Hospital were selected randomly. The age, sex, number of teeth, location, direction, clinical manifestation, anaes-thesia method and operation time were analyzed retrospectively, T test and Chi-square test were used to determine the statistical differences with SPSS 19.0 software package. RESULTS: Among 115 patients, there were 176 impacted supernu-merary, most of them were in mixed dentition period (66.96%), the sex ratio was 2.29:1, and Most patients (59.1%) had one supernumerary tooth, followed by two supernumerary teeth(33.9%). Most supernumerary teeth were located in the middle of the maxilla (68.2%). Inverted ones were the most common (52.8%). The most common symptoms were delayed eruption, displacement, crowding, torsion and space of the adjacent teeth. 92.2% of patients underwent general anesthesia. The dee-per the locations of impacted supernumerary were, the longer the operation time was. CONCLUSIONS: There are regional characteristics of supernumerary teeth in Hefei City, which can provide a reference for clinical diagnosis and treatment.

[Cytotoxicity of carboxymethyl chitosan zinc and peptide to human periodontal ligament cells].

PURPOSE: The purpose of this investigation was to study the cytotoxicity of carboxymethyl chitosan zinc and peptide to human periodontal ligament cells in vitro, in order to provide a reference for understanding materials' safety. METHODS: The primary cells were obtained from human periodontal tissues and cultured. The cultured cells were identified by observing the shape under microscope and by immunocytochemical method. HPDLCs were cultured in different concentrations of the tested materials extract and the activity of cells was evaluated using CCK-8 assay. The cytotoxicity grade was determined in term of the cell relative growth rates. The concentration of the tested materials extract was 100%, 75%, 50% and 25% in group 1-4, respectively. The fifth group had no materials. All statistical analysis was performed using SPSS 17.0 software package. RESULTS: The primary cells owned fibroblasts' shape. Immunocytochemical analysis showed the cells were stained positively to antibodies against vimentin, and negatively to antibodies against cytokeratin, which indicated that they were external embryo mesenchymal cell. The cell relative growth rates were more than 100%, no matter the concentrations of materials extract were. The cytotoxicity grade of CMC-Zn+-P was 0. CONCLUSIONS: CMC-Zn+-P exhibits no cytotoxicity to HPDLCs in vitro, which meets the requirements of the national standard.

[Expression of OPG/RANK/RANKL in the rat dental pulp tissue of periodontitis combined with vascular calcification and its clinical significance].

PURPOSE: To study the expression and possible role of OPG/RANK/RANKLin the rat dental pulp of periodontitis combined with vascular calcification. METHODS: Thirty-six male Wister rats were randomly divided into 4 groups: control group(group C), periodontitis group(group CP), vascular calcification group(group VDN) and compound group(group CP+VDN). Each group underwent corresponding management to establish animal model. When the model was successful, the maxillae including molars were sectioned, pulp tissue was examined by H-E staining; Immunohistochemical staining method was used to evaluate the expression and ratio of OPG and RANKL in pulp tissues. Statistical analysis was carried out using SPSS 19.0 software package. RESULTS: The pulp tissue of group CP, VDN, CP+VDN showed varied degrees of damage, neutrophil infiltration, pulp vascular congestion, odontoblasts vacuolar changes, pulp necrosis by H-E staining, and the changes in CP+VDN group was the most significant, followed by CP group, VDN group. Immunohistochemistry showed OPG in pulp tissues in group CP, VDN, CP+VDN were significantly lower than that in normal group (P<0.05), and the expression in group CP+VDN was the least;Expression of RANKL in pulp tissues in group CP, VDN, CP+VDN were significantly higher than that in normal group(P<0.05)，and the expression in group CP+VDN was the highest. The ratio of OPG/RANKL in normal group was the highest, and the ratio in CP+VDN group was the lowest. CONCLUSIONS: Periodontitis and vascular calcification can damage the pulp tissue, periodontitis compound with vascular calcification may aggravate the injury; OPG/RANKL/RANK system may play an important role in pulp tissue injury.

[The effect of carboxymethyl chitosan zinc and peptide on IL-1,TNF-α and PGE-2 in gingival crevicular fluid of miniature pigs].

PURPOSE: This experiment was aimed at exploring whether carboxymethyl chitosan zinc and peptide （CMC-Zn(+)-P） can reduce the occurrence and development of periodontal tissue inflammation effectively by observing the change of IL-1,TNF-α and PGE-2 level in gingival crevicular fluid （GCF） before and after brushing, so as to find a new effective material in preventing and treating periodontal diseases. METHODS: Miniature pigs were selected as experimental subjects and divided into 4 groups randomly: the control group; CMC-Zn(+)-P group (material group);brushing group; brushing + CMC-Zn(+)-P group (composite group). Gingival crevicular fluid before and one month after the experiment was collected. The levels of IL-1, TNF-α and PGE-2 were examined by enzyme-linked immune-sorbent assay, while the clinical periodontal index was recorded. SPSS 18.0 software package was used for statistical analysis. RESULTS: There was no significant difference in levels of IL-1, TNF-α and PGE-2 and clinical periodontal index between the 4 groups before experiment. After one month, the levels of IL-1, TNF-α, PGE-2 in GCF had significant difference between 4 groups. The levels of IL-1, TNF-α, PGE-2 in composite group were significant lower than that of the other three groups (P<0.008).The levels of IL-1, TNF-α and PGE-2 in the material group and brushing group were significantly lower than that of the control group (P<0.008). Compared with materials group, the brushing group had significantly lower level of IL-1,significantly higher level of PGE-2 ,but no difference in the level of TNF-α.In addition, the teeth calculus index of composite group was significantly lower than that of other groups (P<0.05). CONCLUSIONS: CMC-Zn(+)-P can effectively reduce periodontal tissue inflammation and cut down the speed of deposition of dental calculus. If used cooperatively with brushing, the effect will be better.

[Study of antimicrobial activity of carboxymethyl chitosan zinc complex material against cariogenic bacteria].

PUPPOSE: To evaluate the antimicrobial activity of carboxymethyl chitosan zinc (CMCSZ) and carboxymethyl chitosan zinc-active peptide complex material (CMCSZP) on oral cariogenic bacteria. METHODS: Agar dilution method and K-B disk diffusion susceptibility agents were used to measure the antimicrobial activity of two agents against S.mutans, Lactobacillus, S.sanguinis and Actinomyces viscosus. The former method was used to measure the minimal inhibitory concentration (MIC) and latter was used to measure the inhibitory zone. The effects of pH value, temperature, light, ultraviolet and storage temperature on the active substances were investigated to determine the stability of CMCSZ and CMCSZP. SPSS17.0 software package was used for statistical analysis. RESULTS: All the bacteria were susceptible to active peptide, CMCSZ and CMCSZP with the MIC of CMCSZ/CMCSZP being 625, 1250, 1250 and 2500 mg/L, respectively. At the same concentration, the inhibitory zone of CMCSZP was significantly bigger than that of CMCSZ. Acidic conditions were conducive to increase the antimicrobial activity of CMCSZ, while the effect on CMCSZP was not significant. CMCSZ and CMCSZP exhibited good stability against light, but their antimicrobial activity gradually weakened as the bath temperature rising. In the temperature of 85 degrees centigrade, their antibacterial activity disappeared. CONCLUSIONS: CMCSZ have CMCSZP had strong antimicrobial activity against 4 kinds of cariogenic bacteria. They have good stability against light, but poor thermal stability. This study provides theoretical foundation for the application of CMCSZ/CMCSZP in prevention of cariogenic diseases.

[Effect of lipopolysaccharide on the expression of ALP,BSP,DSPP in rat dental pulp cells].

PURPOSE: To study the changes of expression of dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP) and alkaline phosphatase (ALP) in rat dental pulp cells, which were treated with lipopolysaccharide (LPS). METHODS: Rat dental pulp cells were cultured by the method of tissue block in vitro and identified. The cells were treated with Porphyromonas gingivalis (P.g) LPS at concentrations of 0.1, 1, 10, 100 and 10000 ng/mL. The effects of treatment were respectively examined by the expression of DSPP, BSP and ALP in rat dental pulp cells with real time PCR (RT-PCR) after 1, 3, 5 days of culture. The data was statistically analyzed with SPSS17.0 software package. RESULTS: Under phase contrast microscopy, the adherent cells were found to be primarily typical fibroblasts, and part of the polygonal cells with protuberant cytoplasm. RT-PCR showed that rat dental pulp cells expressed higher mRNA of BSP, DSPP and ALP at concentrations of 1 ng/mL and 10 ng/mL, whereas the expression of BSP, DSPP and ALP mRNA were lower at concentrations of 100 ng/mL and 10000 ng/mL. After 1, 3, 5 days treatment, the expression of BSP, DSPP and ALP gradually reduced in the cells treated with 1, 10, 100 and 10000 ng/mL LPS; while they had no significant change at the concentration of 0.1 ng/mL LPS. CONCLUSIONS: Lower concentration of P.g LPS promotes the expression of ALP, BSP and DSPP in rat dental pulp cells, but larger concentration has inhibitory effect. With the increase of incubation time, the promoting effect decreases gradually, while the inhibition effect increases gradually.

[Expression of mineral-associated factors in the mineral stage tooth germ of mice].

PURPOSE: To study the distribution and expression of core binding factor alpha 1 (Cbf alpha1), bone sialoprotein (BSP), osteopontin (OPN), osteocalcin (OC) and alkaline phosphatase (ALP) in mineral stage tooth germ of mice, so as to understand their roles in the development of the mineral stage tooth germ. METHODS: Thirty BALB/c mice in different days were killed, and their bilateral mandibular first molar germs with surrounding alveolar bone were taken out, then the tissues were fixed with 4% paraformaldehyde at 4 degrees C overnight, dehydrated, embedded in paraffin and serially sectioned at 5 microm. Immunohistochemical assay was adopted to determine the tissue distribution and cellular localization of Cbf alpha1, OPN, BSP, ALP and OC in the mineral stage tooth germ by these sections of BALB/c mice. RESULTS: There were Cbf alpha1, BSP and OPN expressing in the alveolar bone, and Cbf alpha1, ALP, OC in predentin, while in other tissues such as dental follicle, pulp cells, stratum intermedium, stellate reticulum, only ALP and OC were detected, but none of them were observed in the dentin. CONCLUSIONS: The formation mechanisms of hard tooth tissues are different. They are controlled by different factors. Cbf alpha1, ALP and OC are involved in the early formation of dentin, while Cbf alpha1, OPN and BSP involved in the early formation of alveolar bone, ALP involved in the stratum intermedium. They all play an important role in the start of mineralization.

[Expression of epidermal growth factor receptor in human periodontal ligament cells during their mineralization in vitro].

OBJECTIVE: To investigate the expression of epidermal growth factor receptor (EGFR) during the mineralization of human periodontal ligament cells (hPDLC) in vitro. METHODS: Studies using specific antibodies to immunolocalize EGFR in the mineral differentiating hPDLC were undertaken to investigate the different expression during the inducing process. In situ hybridization and RT-PCR technique were used to investigate the transcripts encoding the protein of EGFR. RESULTS: The results showed that immunocytochemical labeling gradually decreased following the elong of the induce time, downing to nearly negative at the 4th week and the signal of EGFR transcripts was weaker in the induced hPDLC than that in uninduced. CONCLUSION: EGFR has a negative regulation function during the mineralization of hPDLC.

[Expression of core binding factor a1, bone morphogenetic proteins and osteopontin in the developing periodontal tissues of mice].

OBJECTIVE: To study the expression and interaction of core binding factor a1 (Cbfa1), bone morphogenetic proteins (BMPs) and osteopontin (OPN) in the developing periodontal tissues of mice. METHODS: A mice developing periodontal tissues study model was created histologically by 5-27 day postnatal BALB/c mice, then the immunohistochemical localization of Cbfa1, BMPs and OPN in different developing stages were undertaken. RESULTS: In early stage of postnatal mice periodontal tissues development, only BMPs expressed in dental follicle cells, though the signal was weak. When root was forming, all of them were expressed in periodontal ligament cells and cementoblasts, while only OPN in acellular cementum, cellular cementum and the surface of alveolar bone, Cbfa1 only in cellular cementum and BMPs was seen in neither acellular cementum nor cellular cementum. CONCLUSION: Cbfa1, BMPs and OPN all involve in the development of periodontal tissues, while OPN is crucial for cementum.

[Immunohistochemical localization of leucine-rich proteoglycans in the developing periodontal tissues of mice].

OBJECTIVE: To study the distribution and expression of fibromodulin, decorin and biglycan in developing normal periodontal tissues, so as to understand its role in periodontal tissue formation. METHODS: Thirty six BALB/c mice in different developing stages were killed and their bilateral mandibular first molars with surrounding alveolar bones and gingival tissues were taken out, Power Vision two steps immunohistochemical method with anti-fibromodulin, anti-decorin and anti-biglycan was used to detect the tissue distribution and cellular localization of fibromodulin and related proteoglycans, decorin and biglycan. RESULTS: Fibromodulin was strongly expressed in the subcutaneous gingival connective tissue, periodontal ligament, mainly in gingival and periodontal fibroblasts as well as their matrices. Strong expression was also noted in the area close to the interfaces of periodontal ligament-alveolar bone and periodontal ligament-cementum. Decorin was strongly expressed in the area of gingival connective tissue, periodontal ligament and the surface of alveolar bone, while biglycan was stained evidently in gingival connective tissue throughout the period of investigation, but negative in the surface of alveolar bone and osteoblasts. CONCLUSIONS: Fibromodulin may interact with decorin and biglycan to regulate the network formation of gingival connective tissues and periodontal collagen fibers, and may be involved in mineralization of the alveolar bone and cementum.

[Expression of Runx2/Cbfa1 in the developing pulpo-dentinal complex of postnatal mice].

OBJECTIVE: To study the expression of Runx2/Cbfa1 in the developing dentin and differentiating odontoblasts. METHODS: A postnatal mice teeth developing model was built histologically. Immunohistochemical technique was adopted to determine the expression of Runx2/Cbfa1 in the developing pulpo-dentinal complex in mice. RESULTS: Runx2/Cbfa1 was merely present in predentin in the exact and before the 11th day's postnatal stages. Meanwhile, it was positively located in odontoblasts and dental pulp cells in root region, but negatively in coral part after the 11th day's stages. CONCLUSION: Runx2/Cbfa1 may play an important role in the deposing of tooth dentin and in the differentiating of odontoblasts and pulp cells.

[Histological location of DMP1, OPN and BSP in cementum formation of mouse].

PURPOSE: To study the distribution of dentin matrix protein 1, osteopontin and bone sialoprotein during cementum formation and cementoblasts differentiation in mouse. METHODS: Thirty six BALB/c postnatal mice were divided into four groups according to the developing stages, nine in each was subdivided into three parts randomly to examine the location of DMP1, OPN and BSP, a tooth developing study model was built and examined using histological methods correspondingly. PV two steps immunohistochemical assay was used to localize the distribution of the three regulatory factors timely and spatially. Repeated measures ANOVA and statistical analysis software of CMIAS were used to analyze the intensity of the dyed images. RESULTS: There was a series expression of the three regulatory proteins. DMP1 was expressed in the dental follicle cells in day 5 of postnatal stages and negatively expressed when the cell began to differentiate; meanwhile, since day 10 and on OPN was positively located in cementoblasts until the root developed completely; but BSP was expressed in the same cell in day 15 to 20, and then decreased to be negative. There were significant differences statistically among the three factors in each stage observed in the study except OPN between day 15 and 25. CONCLUSIONS: There are different locations timely and spatially among the three proteins, it hints that they play important different roles during the differentiation of cementoblasts and formation of cementum.