Showing papers in "West China journal of stomatology in 2019"

Effect of Angelica sinensis polysaccharide on the osteogenic differentiation of bone marrow mesenchymal stem cells of rats with high glucose levels

Abstract: Objective This study aims to evaluate the effect of Angelica sinensis polysaccharide (ASP) on the osteogenic differentiation of the bone marrow mesenchymal stem cells (BMSCs) of rats with high glucose levels. Methods Rat BMSCs were isolated and identified by osteogenic and adipogenic differentiation. Then, the BMSCs were divided into three groups as follows: normal control group (5.5 mmol·L⁻¹ glucose), high glucose group (25.5 mmol·L⁻¹ glucose), and ASP+high glucose group (25.5 mmol·L⁻¹ glucose +40 mg·L⁻¹ ASP). The proliferation activities of the BMSCs were detected by CCK8. Alizarin red staining, and alkaline phosphatase activity were used in the examination of osteogenic activity. Quantitative real time-polymerase chain reaction was used to detect the expression levels of the osteogenic genes (Runx2, Osx, OCN, Col-Ⅰ) and the key factors of Wnt/β-catenin signal pathway (CyclinD1, β-catenin). In vivo, a type 2 diabetes rat model was established. The rats were divided into three groups, namely, the normal control group (normal rats), diabetes group (diabetic rats), diabetes+ASP group (diabetic rats, ASP feeding). Then, the tibia bone defect was established. The repair of bone defects in each group was observed through histological examination. Results The proliferation of BMSCs was higher in the high glucose group and ASP+high glucose group than in the normal control group (P 0.05). The number of calcium nodules of BMSCs; alkaline phosphatase activity; and the mRNA expression of Runx2, OCN, Osx, Col-Ⅰ, CyclinD1, β-catenin in the high glucose group were lower than those in the normal control and ASP+high glucose groups (P 0.05). The bone mass was significantly lower in the bone defect of the diabetes group than in the bone defect of the normal control or diabetes+ASP group (P 0.05). Conclusions ASP can promote the osteogenic differentiation of rat BMSCs under high glucose culture and induce bone regeneration in rats with type 2 diabetes. These features may be related to the activation of the Wnt/β-catenin signaling pathway.

Advances in titanium dental implant surface modification

Abstract: Titanium dental implants have wide clinical application due to their many advantages, including comfort, aesthetics, lack of damage to adjacent teeth, and significant clinical effects. However, the failure of osseointegration, bone resorption, and peri-implantitis limits their application. Physical-chemical and bioactive coatings on the surface of titanium implants could improve the successful rate of dental implants and meet the clinical application requirements. This paper reviews the characteristics of surface modification of titanium implants from the aspects of physics, chemistry, and biology. Results provide information for research and clinical application of dental implant materials.

[In vitro evaluation of the effectiveness of XP-endo Finisher file on smear layer removal after root canal instrumentation].

Abstract: Objective This study aimed to evaluate the effectiveness of XP-endo Finisher (XPF) file and passive ultrasonic irrigation (PUI) in the smear layer removal of the root canal. Methods A total of 60 human single-rooted premolars were selected and decoronated to standardize their canal length to 16 mm. Tooth samples were prepared using a S3 rotary system to prepare root canal with the file size of 3S and then randomly divided into 6 groups according to the final irrigation protocol, as follows: XPF 3 mL of 3% NaOCl for 1 min (group A); XPF 3 mL of 3% NaOCl for 1 min, followed by 4 mL of 17% ethylene diamine tetraacetic acid (EDTA) for 1 min (group B); PUI of 3 mL of 3% NaOCl for 1 min (group C); PUI of 3 mL of 3% NaOCl for 1 min, followed by 4 mL of 17% EDTA for 1 min (group D); 3 mL of 3% NaOCl for 1 min by using a syringe and a 30 G side-vented needle (group E); and 3 mL of 3% NaOCl for 1 min by using a syringe and a 30 G side-vented needle, followed by 4 mL of 17% EDTA for 1 min (group F). After the completion of the root canal preparation, the teeth were split into two longitudinally. The mean numbers of the visible open dentinal tubules in the apical and middle thirds of the root canals were evaluated via scanning electron microscope. Results The whole surfaces of the root canals in groups A, C, and E were covered by a smear layer. Groups A and C possessed significantly higher number of visible open dentinal tubules than in group E (P 0.05). The apical third of the samples in groups B and D and in the middle thirds of canals in group F exhibited a small amount of smear layer, and the dentinal tubules were open or semi-open. The root canal surfaces in the apical third of the samples in group F were covered by a smear layer, and the dentinal tubules were sealed or semisealed. The smear layers in the middle third of the samples in groups B and D were removed, and the dentinal tubules were more visibly open than those of the four other groups (P 0.05). Conclusions The difference between XPF and PUI in terms of the smear layer removal of the root canals was insignificant. Hence, XPF, as a new irrigation agitation technique, can aid in improving smear layer removal.

Human mycobiome and diseases

Abstract: The proportion of mycobiome is less than 1% of human microbiome. However, fungal community plays a key role in human health and diseases. With high-throughput sequencing applications, the structure and composition of mycobiome in the mouth, lung, gut, vagina, and skin have been analyzed, and the role of microbiome in diseases has been investigated. Mycobiome also influences the composition of bacteriome and includes key species that maintain the structure and function of microbial communities. Fungi also influence host immune responses. In this review, we summarized the mycobiome com-position at various sites and different diseases and the interactions between fungi-bacteria and fungi-host.

[Effect of circular RNA hsa_circ_0002203 on the proliferation, migration, invasion, and apoptosis of oral squamous cell carcinoma cells].

Abstract: OBJECTIVE To investigate the effect of circular RNA hsa_circ_0002203 on the malignant biological behavior of oral squamous cell carcinoma (OSCC) cell lines. METHODS Forty patients with oral squamous cell carcinoma were included. Real-time fluorescent polymerase chain reaction (PCR） was used to detect the expression level of circular RNA hsa_circ_ 0002203 in OSCC and corresponding adjacent tissues, OSCC cell lines, and human oral keratinocytes (HOK). SCC15 and CAL27 cells were transfected with lenti-virus. The expression level of circular RNA hsa_circ_0002203 was detected by real-time fluorescent PCR. Cell proliferation was detected by cell counting assay (CCK-8). Cell migration and invasion ability was detected by scratch assay and Transwell migration and invasion assay. Apoptosis level was detected by flow cytometry. The expression of corresponding protein was detected by Western blot. Murine tumor formation experiments were performed to observe the effect of hsa_circ_0002203 on the tumorigenesis of SCC15 cells in vivo. RESULTS The expression of circular RNA hsa_circ_0002203 in OSCC tissues was lower than that in adjacent tissues (P<0.01), and the expression in OSCC cell lines was lower than that in HOK (P<0.001). Hsa_circ_ 0002203 expression increased after the lentiviral infection of SCC15 and CAL27. The proliferation, migration, and invasion of SCC15 and CAL27 reduced, and apoptosis level was promoted. The tumor volume, weight decreased, and growth rate of nude mice decreased. CONCLUSIONS The low expression of circular RNA hsa_circ_0002203 in oral squamous cell carcinoma can enhance the proliferation, migration, and invasion of cancer cells and inhibit tumor cell apoptosis.

[Clinical evaluation of the socket-shield technique for immediate implantation in the maxillary anterior region].

Abstract: Objective This study aimed to evaluate the clinical effect of the socket-shield technique in the maxillary anterior region at one year after implant placement. Methods Ten patients with maxillary anterior teeth that cannot be reserved were enrolled. Implants were installed following the socket-shield technique and restored six months after the surgery. The thickness of the labial maxillary bone of the implant was compared before and one year after the surgery. At one year follow-up, the reten-tion rate of the implants, Jemt classification, and pink and white aesthetic scores were evaluated. Postoperative complications and patient satisfaction were also analyzed. Results One year after installation, the retention rate of the implant was 100%. The thickness of the maxillary bone at the neck, central, and root section of the implant reduced to (0.27±0.21), (0.19±0.20), and (0.28±0.29) mm, respectively, compared with the values immediately after the operation. The thickness of the labial maxillary bone at the three measurement points immediately after and one year after the operation was statistically significant (P 0.05) of the difference thickness between immediate and one year after operation at the three measurement points. The pink esthetic scores of the implant prosthesis was 9.10±0.54, and the white esthetic scores was 9.00±0.63. No complications were observed, and the patients had a high degree of satisfaction. Conclusions The socket-shield technique could provide acceptable treatment results but cannot completely avoid the reconstruction of the labial maxillary bone of the implants. The technique exhibits favo-rable short-term aesthetic result, but its long-term clinical effect and aesthetic problems need to be further studied.

Comparison of clinical effects of a modified socket shield technique and the conventional immediate implant placement

Abstract: OBJECTIVE To compare the clinical effects of a modified socket shield technique (SST) and the conventional immediate implant placement in the esthetic zone. METHODS Twenty-four patients with one hopeless upper incisor were consecutively enrolled in this study. All patients were scheduled for immediate implant placement. Twelve patients underwent a modified SST (experimental group) whereas the others underwent conventional procedures (control group). Radiographic and clinical data were obtained preoperatively, immediately after surgery, and 12 months after surgery. The success rate of the implants, the pink esthetic score (PES) and patient satisfaction were analyzed. Statistical analysis was conducted using SPSS 21.0 software. RESULTS One year after operation, the success rate of the implants was 100% in both groups. The PES and patient satisfaction of the experimental group were significantly higher than those of the control group (P<0.05). The buccal bone plate resorbed less in the experimental group than in the control group (P<0.05). CONCLUSIONS The modified SST is advantageous over the conventional immediate implant placement in terms of buccal bone and soft tissue maintenance.

Effect of sclerostin on the functions and related mechanisms of cementoblasts under mechanical stress

Abstract: Objective The purpose of this study is to investigate the potential effects of sclerostin (SOST) on the biological funtions and related mechanisms of cementoblasts under mechanical stress. Methods OCCM-30 cells were treated with varying doses of SOST (0, 25, 50, and 100 ng·mL⁻¹) and were loaded with uniaxial compressive stress (2 000 μ strain with a frequency of 0.5 Hz) for six hours. Western blot was utilized to detect the expressions of β-catenin, p-smad1/5/8, and smad1/5/8 proteins. Alkaline phosphatase (ALP) activity was determined, and reverse transcription polymerase chain reaction was used to measure the expressions of runt-related transcription factor 2 (Runx-2), osteocalcin (OCN), bone sialoproteins (BSP), receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) mRNA. Results The expression of p-smad 1/5/8 was significantly downregulated with increasing SOST. β-catenin and smad1/5/8 exhibited no difference. ALP activity decreased under mechanical compressive stress with increasing SOST concentrations. Runx-2 expression was reduced with increasing SOST concentrations, and a similar trend was observed for the BSP and OCN expressions. When the SOST concentration was enhanced, RANKL expression gradually increased, whereas the expression of OPG decreased. Conclusions Under mechanical comprehensive stress, SOST can adjust the bone morphogenetic protein (BMP) /smad signal pathway. Osteosclerosis inhibits the mineralization of cementoblasts under mechanical compressive stress, which may be achieved by inhibiting the expressions of osteogenesis factors (Runx2, OCN, BSP, and others) and by promoting the ratio of cementoclast-related factors (RANKL/OPG) through BMP signal pathways.

Mechanism of participation of osteocytes in the formation of osteoclasts under hypoxia

Abstract: OBJECTIVE To investigate the mechanism of the participation of osteocytes in the formation of osteoclasts under hypoxia. METHODS The hypoxia culture system of osteocyte-like cell line MLO-Y4 was established by deferoxamine mesylate (DFO) in vitro. The proliferation of MLO-Y4 cells was examined by CCK-8 cell proliferation/toxicity assay. RAW264.7 cells were induced to osteoclasts by the conditioned medium containing the cultured MLO-Y4. Tartrate-resistant acid phosphatase (TRAP) staining was performed on day 7. Quantitative real-time fluorescence polymerase chain reaction, immunofluorescence, and Western blot were used to detect the expression levels of hypoxia-inducible factor (HIF)-1α and receptor activator of nuclear factor-κB ligand (RANKL) in MLO-Y4 under hypoxia. The effects of siHIF-1α on the expression levels of HIF-1α and RANKL in MLO-Y4 under the same conditions were detected. RESULTS DFO (100 μmol·L⁻¹) promoted the proliferation of MLO-Y4 at 24 h, which decreased with time (P<0.01). After the addition of soluble sRANKL, the formation of osteoclasts was significantly increased in the DFO group (P<0.001). The expression of RANKL mRNA in MLO-Y4 under 100 μmol·L⁻¹ DFO increased first and then decreased with the duration of hypoxia. This expression reached a peak at 24 h (P<0.01). Hypoxia up-regulated the expression of HIF-1α and RANKL protein (P<0.01). Under hypoxia, siHIF-1α downregulated the expression of HIF-1α and RANKL (P<0.01). siHIF-1α also decreased the number of osteoclasts (P<0.01). CONCLUSIONS Under hypoxia, MLO-Y4 could facilitate the formation of RANKL through upre-gulating the expression of HIF-1α protein, thereby accelerate the differentiation of RAW264.7 cells into osteoclasts.

[All-ceramic premolar guiding plate retains resin-bonded fixed partial dentures].

Abstract: Objective This study aims to investigate the fracture resistance and short-term restorative effects of resin-bonded fixed partial dentures (RBFPDs) made from heat-pressed lithium-disilicate-based glass-ceramic (IPS e.max press) and zirconia ceramic (WIELAND) and retained by all-ceramic guiding plates when used to restore missing mandibular second premolars. Methods A total of 64 human mandibular first premolars and first molars were prepared as abutments, then were randomly divided into 4 groups (n=8): E0, heat-pressed ceramic RBFPDs, no cyclic loading; E1, heat-pressed ceramic RBFPDs exposed to 300 000 cycles of dynamic loading; W0, zirconia ceramic RBFPDs, no cyclic loading; and W1, zirconia ceramic RBFPDs exposed to 300 000 cycles of dynamic loading. Fracture strength was tested in a universal testing machine. Results The medians of fracture strength were 1 242.85 N±260.11 N (E0), 1 650.85 N±206.77 N (W0), 1 062.60 N±179.98 N (E1), and 1 167.61 N±265.50 N (W1). Statistical analysis showed that all the groups exhibited significantly higher fracture strength compared with the maximum bite force in the premolar region (360 N; P 0.05). Significant statistical differences were found between the zirconia ceramic groups (W0 and W1, P 0.05) after dynamic loading. Conclusions The RBFPDs retained by all-ceramic guiding plates exhibited promising fracture properties and optimal short-term restorative effects when used to restore missing mandibular second premolars.

Prevalence and influencing factors of deciduous caries in preschool children in Chongqing city

Abstract: OBJECTIVE This study aimed to determine the prevalence and related factors of deciduous caries in 3-5-year-old preschool children in Chongqing city. Results will be used to provide a basis for the establishment and adjustment of prevention and intervention of caries in preschool children. METHODS We referred to the Fourth National Oral Health Epidemiological Survey. Data included caries prevalence in preschool children, and the questionnaires were distributed to children' parents in Chongqing city. Results were inputted by Epidata 3.1 and statistically analyzed using SPSS 21.0. RESULTS A total of 1 350 preschool children were included in the study. We found that maxillary deciduous central incisor and mandibular deciduous molars were susceptible to decay. The prevalence of primary teeth caries in preschool children in Chongqing city was 51.4% (694/1 350). The mean decayed-missing-filled-teeth (dmft) index was 2.34. The caries prevalence and mean dmft between age groups were statistically significant (P 0.05). Approximately 61.7% of caries cases were concentrated in a small number (36.1%) of individuals. Multivariate Logistic regression analysis showed that age, highest educational level of parents, intake frequency of sweetened beverages and carbonated drinks, toothache or similar discomfort experience over the past year, dentist visits, and parents' assessment of teeth and oral health status of children were the factors influencing the prevalence of deciduous caries (P<0.05). CONCLUSIONS More than half of the preschool children had dental caries. Majority of caries were concentrated in a small number of individuals. The age of children, highest educational level of parents, intake frequency of sweetened beverages and carbonated drinks, toothache or discomfort experience over the past year, dentist visits, and parents' assessment of teeth and oral health status of children were associated with the prevalence of deciduous caries.

[Preparation and evaluation of carboxymethyl chitosan/sodium alginate hydrogel for cartilage tissue engineering].

Abstract: Objective This study aimed to optimize the preparation of carboxymethyl chitosan/sodium alginate (CMCS/OSA) compound hydrogels. This study also aimed to investigate the applicability of the hydrogels in cartilage tissue engi-neering. Methods Three groups of CMCS/OSA composite hydrogels with amino-to-aldehyde ratios of 2∶1, 1∶1 and 1∶2 were prepared. The microstructure, physical properties, and cell biocompatibility of the three groups of CMCS/OSA com-posite hydrogels were evaluated. Samples were subjected to scanning electron microscopy, rheological test, adhesion tension test, swelling rate test, and cell experiments to identify the CMCS/OSA composite hydrogel with the cross-linking degree that can meet the requirements for scaffolds in cartilage tissue engineering. Results The experimental results showed that the CMCS/OSA hydrogel with a amine-to-aldhyde ratio of 1∶1 had good porosity, suitable gelling time, strong adhesive force, stable swelling rate, and good cellular biocompatibility. Conclusions The CMCS/OSA compound hydrogel prepared with a 1∶1 ratio of amino and aldehyde groups has potential applications in cartilage tissue engineering.

Analysis of the risk factors of radiation-induced caries in patients with head and neck cancer

Abstract: Objective This study aimed to evaluate the risk factors of radiation-induced caries by using a multiple linear regression equation and to provide the basis for the effective prevention of radioactive caries. Methods A total of 166 patients with head and neck cancer who underwent radiotherapy were selected as subjects. The number of decayed, missing or filled surfaces were recorded. Questionnaire contents included age, sex, radiation dose, and radiotherapy techniques. Multiple stepwise regression analyses were performed to identify the risk factors of radiation-induced caries. Results Multiple stepwise regression analyses indicated that the main risk factors of radiation-induced caries were plaque index, radiotherapy techniques, time after radiotherapy, and radiotherapy dose. Conclusions The awareness of dental care and caries treatment should be improved to reduce the occurrence of radiation-induced caries in patients with head and neck cancer. In addition, intensity modulated radiation therapy should be employed to decrease the radiation exposure dose received by teeth.

Research progress on the modification of guided bone regeneration membranes

Abstract: Guided bone regeneration (GBR) is an important technique to solve bone defect problems. In this technique, GBR barrier membranes play an irreplaceable role. GBR membranes can act as a barrier protecting fibroblasts from bone defects and promote osteoblast adhesion and proliferation, leading to bone regeneration. GBR barrier membranes should be enhanced because of the disadvantages of collagen membranes, which are extensively applied to the field of GBR. Therefore, various efforts have been devoted to modifying the antibacterial and osteogenic properties of GBR barrier membranes and developing novel materials. This article reviews the research advancements on the modification of GBR barrier membranes and discover future directions for the development of GBR barrier membranes to provide a reference for bone tissue engi-neering and repair.

Evaluation of the color stability of infiltrant resin in comparison to aesthetic composite resins

Abstract: OBJECTIVE To investigate the color stability of infiltrant resin together with three other composites exposed to staining solution. METHODS Three types of anterior aesthetic composite resins (Filtek Z250, Filtek Z350 XT, and Beautiful Flow Plus F00) and artificial caries with Icon infiltrant resin were used. The samples were randomly divided into two groups (each contained 10 specimens): coffee solution and distilled water immersion for three weeks. Color parameters were deter-mined with the Crystaleye spectrophotometer. RESULTS Artificial caries lesions infiltrated by Icon showed much higher ΔE than those infiltrated by other aesthetic resins (P<0.05). The discoloration of all the experimental resins and the artificial caries infil-trated with Icon increased with time, but the discoloration on the 1st week was significantly higher than those on the 2nd and 3rd weeks. CONCLUSIONS Artificial caries infiltrated with Icon was more vulnerable and susceptive to food color than those infiltrated with other aesthetic composite resins.

[Environmental factors of non-syndromic cleft lip and palate].

Abstract: Though the mechanism of non-syndromic cleft lip and palate is not completely clear, the disease is affected by the combination of environment and genetics. Special environmental factors have the affect on the incidence of cleft palate. In this paper, the environmental factors related to the occurrence of non-syndromic cleft lip and palate were summarize from three aspects: poor living habits, chemical factors, age and health status of pregnant women during pregnancy. Based on the analysis of this paper, it will help to improve the health and living environment of pregnant women, so as to reduce the incidence of cleft palate.

Clinical value of vacuum sealing drainage in the treatment of oral and maxillofacial space infection

Abstract: Objective This study aims to observe the efficacy of vacuum sealing drainage (VSD) by continuous negative pressure drainage and saline irrigation in the treatment of oral and maxillofacial space infection. Methods Retrospective analysis was conducted on 116 cases of maxillofacial space infection, and clinical data were collected to compare the therapeutic effects of routine incision with drainage treatment (traditional treatment group, 58 cases) and VSD treatment (VSD group, 58 cases). Results The length of hospital stay, white blood cell count, scar length, frequency of dressing change, and pain degree of patients in the VSD group were all lower than those in the traditional treatment group. Moreover, the improvement degree of mouth opening in the VSD groups was better than that in the traditional treatment group (P Conclusions VSD is a more effective method for the treatment of oral and maxillofacial space infection.

Clinical application of laser in crown lengthening

Abstract: Crown lengthening is one of the most common surgeries in clinical practice. Under the premise of ensuring the biologic width, the adequate crown is exposed by resecting the periodontal soft tissue and (or) hard tissue to meet the prosthodontic and (or) aesthetic requirements. Considering the various advantages of oral laser, such as safe, precise, minimally invasive and comfort, laser has become a promising technology which can be used to improve the traditional crown lengthening. In this review, the principles and characteristics of laser application in crown lengthening, especially in the minimally invasive or flapless crown lengthening will be reviewed. Its pros and cons will also be discussed.

Effects of concentrated growth factors on relieving postoperative reaction of guided bone regeneration in the esthetic zone

Abstract: Objective To explore the effect of concentrated growth factors (CGF) on postoperative pain and swelling in patients with complex dental implants. Methods A total of 28 patients with single maxillary anterior teeth loss and labial orbital bone defect were recruited randomly and divided into two groups. Each group included 14 patients. The experimental group was applied with CGF membrane to guide bone regeneration, whereas the control group was treated with collagen membrane to guide bone regeneration. The postoperative pain degree and swelling degree were compared, and data were analyzed with SPSS 23.0 software. Postoperative pain was measured by visual analogue scale (VAS), and the degree of swelling was divided into four grades according to swelling range. Results VAS scores of patients in experimental and control groups reached 35.1±22.5 and 47.0±20.3, respectively. The duration of postoperative pain in experimental and control groups totaled (2.1±1.5) and (2.8±1.0) days, respectively. No statistically significant difference was observed between the two groups (P>0.05). Percentages of non-swelling, mild swelling, moderate swelling, and severe swelling in experimental group reached 21.4%, 57.1%, 21.4%, and 0, respectively, and those in control group were 7.1%, 35.7%, 35.7%, and 21.4%. Swelling duration reached (2.4±1.4) and (4.2±2.2) days in the experimental and control groups, respectively. A statistically significant difference was observed in the swelling degree of experimental and control groups (P Conclusions The use of CGF can significantly reduce the degree of postoperative swelling and shorten swelling time but cause no significant effect on pain.

[Research progress on platelet-rich fibrin derivatives].

Abstract: Platelet-rich plasma and platelet-rich fibrin (PRF) are widely used in the field of stomatology. Advance-ments in preparation techniques and basic research have enabled the use of PRF derivatives in oral clinical applications. The evolution, preparation techniques, biological properties, and medical research progress of PRF derivatives are reviewed in this paper.

[Minimal invasive microscopic tooth preparation based on endodontic, periodontal and functional health].

Abstract: Tooth preparation is the primary and core operation technique for dental esthetic restoration treatment, due to its effect of providing restoration space, bonding interfaces and marginal lines for dental rehabilitation after tooth tissue reduction. The concept of microscopic minimal invasive dentistry put forward the issue of conducting high-quality tooth preparation, conserve tooth-structure, protect vital pulp and periodontal tissue simultaneously. This study reviewed the concepts, physiology background, design and minimal invasive microscopic tooth preparation, and in the meantime, individualized strategies and the two core elements of tooth preparation (quantity and shape) are listed.

Oral microbiological diversity in patients with salivary adenoid cystic carcinoma

Abstract: OBJECTIVE The aim of this study was to identify the differences in microbial diversity and community in patients with salivary adenoid cystic carcinoma (SACC). METHODS Saliva was collected from 13 patients with SACC confirmed by histopathological diagnosis and 10 healthy control subjects. Total metagenomic DNA was extracted. The DNA amplicons of the V3-V4 hypervariable regions of the 16S rRNA gene were generated and subjected to high-throughput sequencing. Microbial diversity and community structure were analyzed with Mothur software. RESULTS A total of 16 genera of dominant bacteria in the SACC group were found, including Streptococcus (36.68%), Neisseria (8.55%), Prevotella_7 (7.53%), and Veillonella (6.37%), whereas 15 dominant bacteria in the control group were found, including Streptococcus (18.41%), Neisseria (18.20%), Prevotella_7 (8.89%), Porphyromonas (6.20%), Fusobacterium (5.86%) and Veillonella (5.82%). The statistically different phyla between the two groups were Firmicutes, Proteobacteria and Fusobacterium (P<0.05). The statistically different genera between the two groups were Streptococcus, Neisseria and Porphyromonas (P<0.05), and Capnocytophaga was only detected in patients with SACC. CONCLUSIONS Significant differences were observed in the oral microorganisms between the two groups.

[Three-dimensional morphological analysis of the palate of mouth-breathing children in mixed dentition].

Abstract: OBJECTIVE To study the effects of mouth-breathing on maxillary arch development by comparing the palatal morphology of mouth- and nose-breathing children in mixed dentition. METHODS Children in mixed dentition were enrolled and categorized into mouth-breathing (test group) and nose-breathing groups (control group) according to their breathing patterns. Children's plaster models were scanned with 3D laser scanner, and the 3D data were reconstructed and measured using Minics 15.0 and Geomagic 12.0 software. Measurement data (inter-molar width, palatal height, palatal volume, and palatal surface area) of the two groups were compared, and the correlation among the four measurement items was analyzed. RESULTS The participants were 73 children (37 in test group and 36 in control group) with a mean age of (8.63±0.78) years old. The test group had significantly smaller inter-molar width, palatal volume, and palatal surface area but significantly higher palatal height than the control group (P<0.05). Inter-molar width and palatal volume were positively correlated with the palatal surface area in the test group (P<0.05). Inter-molar width and palatal height were positively correlated with the palatal surface area in the control group (P<0.01). CONCLUSIONS Mouth-breathing children have significantly reduced inter-molar width, palatal volume, and surface, and substantially increased palatal height, leading to different developmental patterns of the palatal morphology.

[Effect of long chain non-coding RNA H19 on the migration and invasion of oral cancer cells and its molecular mechanism].

Abstract: OBJECTIVE To investigate the effect of the long chain non-coding RNA H19 (lncRNA H19) on the invasion and migration of oral cancer cells and its related molecular mechanism. METHODS The expression levels of lncRNA H19, miR-107, and cyclin-dependent kinase 6 (CDK6) in the immortalized oral epithelial cell line HIOEC and the oral cancer cell line CAL27 were detected by real-time quantitative polymerase chain reaction. CAL27 cells were transfected with siRNA H19, miR-107 mimics, pcDNA H19, or anti-miR-107, and the effects of H19 and miR-107 on the invasion and migration of cells were examined via Transwell assay. The TargetScan database predicted the targeting of H19, miR-107, and CDK6. Double luciferase reporter gene assay was performed to detect interactions among H19, miR-107, and CDK6. Western blot analysis was conducted to examine the effects of H19 and miR-107 on the protein level of the target gene CDK6. RESULTS Compared with that in HIOEC cells, the expression of H19 was significantly increased in CAL27 cells (P<0.05). After transfection with siRNA H19, the expression of H19 decreased, and the invasion and migration ability of CAL27 cells were inhibited (P<0.05). H19 could bind specifically to the 3'-UTR of miR-107 to modulate the expression of miR-107. Compared with that in HIOEC cells, the expression of miR-107 significantly decreased in CAL27 cells (P<0.05). The expression of miR-107 increased after transfection with siRNA H19, and anti-mir-107 co-transfection could promote the invasion and migration ability of siRNA H19 in CAL27 cells (P<0.05). Compared with that in HIOEC cells, CDK6 expression significantly increased in CAL27 cells (P<0.05), and the expression level of the gene was coregulated by H19 and miR-107 (P<0.05). CONCLUSIONS lncRNA H19 plays an important role in the development of oral cancer. It can regulate the invasion and migration of oral cancer cells by targeting the miR-107/CDK6 signaling axis.

[Bioinformatics analysis of programmed cell death ligand 1 co-expression genes and their regulatory network in head and neck squamous cell carcinoma].

Abstract: OBJECTIVE This study aimed to construct a network of programmed celldeath ligand 1 (PD-L1) co-expression genes and screen potential biomarkers for PD-L1 expression in head and neck squamous cell carcinoma (HNSCC) by bioinformatics analysis. Moreover, the genes and pathways participating in PD-L1 and regulating the tumor immune status were determined. METHODS The HNSCC transcriptomic dataset in TCGA was selected to retrieve gene sets on the cBioPortal platform, where PD-L1 co-expressional genes were acquired. With these genes, GO-BP, KEGG, and string analyses were performed in R clusterProfiler. Cytoscape was used for network analysis and hub gene screening. RESULTS A total of 117 co-expression genes were obtained, most of which were enriched in immune regulation and response to viral processes. Node degree analysis indicated that STAT1, IFNG, CXCL10, CCR5, FCGR3A, CXCL9, GBP5, CD86, GZMB, IRF1 were the highest connected genes and functioned as hub genes. Survival analysis of these hub genes resulted in CCR5, CXCL9, and GZMB as the prognostic biomarkers for patients with HNSCC, all of which were involved in immune regulation and their expression levels were related to PD-L1 (Pearson correlation coefficient was 0.30, 0.35, 0.39; P<0.01). High expression levels of these three hub genes were protective factors in patients with HNSCC. CONCLUSIONS PD-L1 co-expression hub genes are related to immunity, among which CCR5, CXCL9, and GZMB are prognostic markers with the possibility to be involved in programmed cell death protein 1 (PD-1)/PD-L1-induced tumor immune escape. These genes provide new clues to study the mechanism and precision target medicine of PD-1/PD-L1 in HNSCC.

[Three-dimensional finite element analysis of different endodontic access methods and full crown restoration in the maxillary central incisor].

Abstract: Objective This study evaluates the effects of different endodontic access methods and full-ceramic crown on the stress distribution in the maxillary central incisor by using three-dimensional finite element analysis. Methods Computed tomography scans of the maxillary central incisor were used to construct a three-dimensional finite element model of the maxillary central incisor. According to the different methods of endodontic and the prosthetic treatments, four models were established, namely, group A (traditional access cavity preparation with resin filling), group B (traditional access cavity preparation restored full-ceramic crown), group C (minimally invasive endodontics with resin filling) and group D (minimally invasive endodontics restored full-ceramic crown). A static force of 100 N and a direction of 45° was applied to the long axis of the tooth at the junction of the incisal section one-third and middle section one-third. The maximum principal stress, the von Mises stress and the modified von Mises stress of the tooth tissue were analyzed using the finite-element analysis software. Results 1) Stress peaks: the stress peaks of the maximum principal stress, the von Mises stress and the modified von Mises in group A were the largest, except that the stress peak of von Mises stress in group D was slightly lower than that in group C. The stress peaks of the maximum principal stress and the modified von Mises in group C were the lowest. The stress peaks of the maximum principal stress and the modi-fied von Mises stress in group D were lower than those in groups A and B. 2) Stress distribution: compared with group A, the stress distribution of cervical dentin and the area of stress concentration in group C was lower and smaller. In the root dentin, the stress distribution in group C was more uniform than that in group A, and the stress was dispersed to several areas of the root apex. After crown restoration, no significant difference was observed in stress distribution between groups B and D in the root region. The stress distribution state of group B was not significantly different from that of group A. No significant difference was observed in the stress distribution state between groups D and C. Conclusions 1) From the perspective of biomechanics, the minimally invasive access was adopted for the maxillary central incisor. 2) Full crown restoration is recommended after traditional access cavity preparation. No obvious advantage is observed in stress analysis for minimally invasive endodontics-restored full-ceramic crown.

[Influence of periodontal non-surgical therapy on serum interleukin 6 expression and carotid artery wall in rats with periodontitis and type 2 diabetes mellitus].

Abstract: OBJECTIVE To study the effect of periodontal non-surgical treatment on serum interleukin-6 (IL-6) expression and carotid vascular wall in a rat model of chronic periodontitis (CP) with type 2 diabetes mellitus (T2DM). METHODS Twenty-eight 6-week-old SD rats were randomly divided into group A (control group, 7 rats) and group B (T2DM+CP group, 21 rats). According to different intervention measures, group B was randomly subdivided into B1 (natural process), B2 (periodontal mechanical treatment), and B3 (periodontal mechanical treatment + 2% minocycline hydrochloride + systemic metronidazole plus amoxicillin). Serum IL-6 was measured by enzyme-linked immunosorbent assay, and carotid tissue was observed under light microscopy after hematoxylin-eosin (HE) staining. RESULTS The carotid artery wall of group A was normal. In group B1, the endothelial cells disappeared, the elastic fibers of the middle membrane were disordered, the local necrosis of smooth muscle tissue was amorphous particles, a small amount of calcium salt was deposited, and the wall thickening was obvious. The endothelial cells in groups B2 and B3 disappeared, and the smooth muscle cells in the middle membrane underwent denaturation. No significant thickening of the vessel wall was noted. The serum IL-6 level in group B1 continually increased with time, and it was higher than that in group A (P<0.001). The IL-6 levels of groups B2 and B3 peaked a week after the first intervention. Subsequently, IL-6 levels gradually decreased. At the last point (five weeks after the second intervention ), the IL-6 levels of groups B2 and B3 were significantly lower than that of group B1 (P<0.001). CONCLUSIONS For rats with periodontitis and diabetes, periodontal mechanical treatment may elevate serum IL-6 levels in the short term but might reduce the whole inflammatory state in the long term. Thus, this treatment might be valuable to the improvement of vascular disease. The adjunctive benefits of systemic metronidazole and amoxicillin in non-surgical periodontal therapy are decreased serum IL-6 expression and normal carotid artery.

Characteristics of mandible and mandibular dentition according to vertical facial skeletal features of adolescents

Abstract: Objective We aim to examine teenagers with varying vertical facial skeletal types with near-normal occlusion. We further aim to identify and study mandibular morphology and dentition characteristics to establish normal ranges and variations for future clinical reference. Methods According to the results of the case studies, 42 adolescents with near-normal occlusion were divided into three groups, namely, low- (7 cases), average- (23 cases) and high-angle (12 cases) groups. We used Invivo 5 software for Digital Imaging and Communications in Medicine (DICOM) data to calculate the cant of occlusal plane, axis corner of L6, ∠L1/MP, ∠L6/MP, Balkwill angle and Bonwill triangle of each group. Results Markedly, the finding shows that the cant of occlusal plane and axis corner of L6 in the low-angle group were smaller than those of the other two groups. In the average-angle group, ∠L1/MP was larger than that of the high-angle group. Lastly, in the high-angle group, ∠L6/MP was smaller than those of the two other groups. On the one hand, these differences were considered statistically significant (P 0.05). Conclusions In the low-angle group, the parallelisation of the occlusal plane tends to be more obvious compared with the two other groups. In the coronal section of the low-angle group, the axis of the mandibular first molar is up-right, whereas it is distally tilted in the sagittal section of the high-angle group. Furthermore, a number of differences are noted in the adult groups. Factors, such as aging and development in the craniofacial region, lead to changes in functional occlusion.

[Research progress on 3D printing metal powders used in cranio-maxillofacial prosthesis].

Abstract: With the rapid development of 3D printing, it is widely used in the field of cranio-maxillofacial surgery. Through the individualized production of 3D printing, the backward mode of traditional production relying on manual shaping has been changed to meet the needs of different patients. However, as no clear specification exists for the performance requirements of 3D printing metal powder for cranio-maxillofacial surgery, its long-term development is not feasible. In this paper, the preparation technologies of 3D printing metal powder for cranio-maxillofacial prostheses (i.e., gas atomization, rotating electrode atomization, and radio frequency plasma spheroidization) and 3D printing forming technologies (i.e., selective laser melting, electron beam selective melting, and laser-engineered net shaping) are introduced. The performance requirements of 3D printing metal powder for cranio-maxillofacial prostheses are then summarized according to the characteristics of the preparation and forming technologies described.

Risk factors of oral Helicobacter pylori infection among children in two kindergartens in Suzhou and the effects of oral cleaning on reducing oral Helicobacter pylori infection

Abstract: OBJECTIVE This work aimed to identify the risk factors of Helicobacter pylori (H. pylori) infection in preschool children and provide effective measures for the prevention and reduction of the incidence of H. pylori infections. METHODS A total of 204 children from two kindergartens in Suzhou city were recruited through a questionnaire survey. Risk factors were selected through the single factor paired data χ² test and multiple factor Logistic regression analysis. Oral and gastric H. pylori infections were detected by using H. pylori saliva detection (HPS) and ¹³C-urea breath test (¹³C-UBT). Special toothpaste for H. pylori control was selected for oral cleaning. Oral H. pylori infection rates at 2 months after special toothpaste treatment were examined by using HPS. RESULTS The high-risk factors of H. pylori infections among preschool children included poor personal hygiene habits, such as the nibbling of fingers and the avoidance of hand-washing before meals, diet, and parent's history of stomach disease. Among the 204 subjects enrolled in this study, 158 (77.45%), 37 (18.14%), and 28 (13.73%) were HPS positive, ¹³C-UBT positive, and HPS and ¹³C-UBT positive, respectively. The incidence of oral H. pylori infections was significantly higher than that of gastric H. pylori infections (P<0.01). The positive rate of infections significantly decreased after special toothpaste treatment (P<0.01). This result indicates that the intervention was effective. CONCLUSIONS Children must receive education on good eating habits. Individualized dining habits or the use of public chopsticks must be implemented. H. pylori infections must be detected as early as possible. Specific toothpaste for oral cleaning must be selected. These approaches could drastically prevent or reduce the incidence of H. pylori infections among preschool children.