Evaluation of residual bone mass of the mandibular third molar and the risk of mandibular fracture.

BACKGROUND: A quantification of the residual bone mass of the mandible (B/A) was utilized in this study to examine the correlation between mandibular fracture and residual bone mass. To improve the clinical utilization rate and reduce the incidence of iatrogenic mandibular fractures, the B/A ratio calculation should be simplified. MATERIAL AND METHODS: Data were collected from the Yanbian University Hospital on 175 cases of mandibular fracture with third molar (M3), 67 normal cases without fractures and 20 cases of impacted teeth extraction. Twenty cases of iatrogenic mandibular fracture were collected, and the case records and panoramic radiographs of the patients were recorded. RESULTS: The average B/A ratio of mandibular angle fracture group was 0.61±0.10.The value of B/A was found to be statistically significant in terms of whether M3 emerged from alveolar bone (P = 0.001), location (horizontal P < 0.001, vertical P < 0.001), the degree of impaction (P < 0.001), the number of roots (P < 0.001), the difference in impaction (P < 0.001), and the fracture type (P = 0.002). The average B/A ratio of normal group was 0.62±0.10. In the statistical results of the B/A value of normal patients, M3 involving alveolar bone (P < 0.001), position classification (P < 0.05), degree of impaction (P < 0.001) and presence or absence of a root (P < 0.05) were statistically significant. The average B/A ratio of iatrogenic mandibular angle fracture group was 0.28±0.08. The average B/A ratio of the extraction group for impacted teeth was 0.62 ± 0.09. CONCLUSIONS: There is a high risk of mandibular angle fracture when the (B/A) value of the residual bone height (B) in the mandibular M3 area compared to the mandibular bone height (A) in the M3 area is less than 0.4.

Relationship between mandibular third molars and mandibular angle and condylar fractures.

BACKGROUND: Assess the correlation between the position of the third molar (M3) and fractures of the mandibular angle and condyle using panoramic radiographs to offer valuable data references for oral clinical research. MATERIAL AND METHODS: A retrospective cross-sectional study was undertaken, involving the collection of 409 cases of mandibular fracture in the Yanbian University Hospital. The case records and panoramic radiographs of mandibular angle fracture (78 cases) and condylar fracture (106 cases) were evaluated. RESULTS: In the comparative analysis between the mandibular angle fracture group and the condylar fracture group, statistical significance was observed in the variables of M3 existence (P = 0.002), eruption of M3 from the alveolar cavity (P = 0.003), P&G position classification (P = 0.001), deep impactions (Classes IC, IIC, IIIB, and IIIC) (P < 0.001), and the presence of impacted M3 in both groups (P < 0.001).Regarding M3 roots, the mandibular angle fracture group exhibited the highest prevalence of multiple roots at 75.4%, surpassing the 64.6% observed in the condylar fracture group. The prevalence of proximal angles in the mandibular angle group and the condyle group was the highest, accounting for 64.6% and 61.5%, respectively. The percentage of M3 in the two groups was 80% and 43.1%, respectively, with a significant difference (P < 0.001). CONCLUSIONS: Impacted mandibular third molars (M3) elevate the risk of mandibular angle fractures, while their absence or normal eruption reduces this risk and protects against condylar process fractures. The fracture risk is influenced by the M3's position: P&G Class II and Class B impactions, where M3s emerge partially from the alveolar bone, are significantly associated with mandibular angle fractures. In contrast, the absence of M3 or its placement in P&G Class I and Class A positions tends to correlate with a higher incidence of condylar process fractures.

Optimization of environmental factors in a dual in vitro biofilm model of Candida albicans-Streptococcus mutans.

The biofilm formation of Streptococcus mutans-Candida albicans is an important virulence factor for dental caries. The purpose of this study was to determine the effect of some environmental conditions on the biofilm formation like inoculation concentration, temperature, sugar, amino acid, metal ions and saliva, and then establish a persistent in vitro biofilm model for further research. Based on the single factor experiment, the factors participating in the biofilm formation including sugar, inoculation concentration, and saliva increased the biofilm mass, while amino acid, metal ions, temperatures reduced biofilm mass. Optimal conditions for biofilm formation were the inoculation dosage of S. mutans and C. albicans of 108 and 107 , respectively, the addition of 0·3 g l-1 sucrose and sterile saliva. These results contribute to a deep understanding of the factors involved in oral biofilm formation of the important cariogenic pathogen S. mutans and the opportunistic pathogen C. albicans to study better for biofilm and promote the design of new therapeutic approaches. The present research also provides a model for evaluating the therapeutic potential for drugs in the future.

Initiation and progression of dental-stimulated temporomandibular joints osteoarthritis.

Temporomandibular joint (TMJ), a site that is often impacted by osteoarthritis (OA), is biomechanically linked with dental occlusion. Tissue responses in TMJ condyle to biomechanical stimulation could be investigated by intervention of the dental occlusion in animals. Unilateral anterior crossbite, an experimental malocclusion, has been demonstrated to induce TMJ-OA lesions, showing primarily as enhanced cartilage calcification and subchondral cortical bone formation at the osteochondral interface, causing the osteochondral interface thickening and stiffening. The changed interface would worsen the local biomechanical environment. At the cartilage side, the matrix degenerates. In the case of insufficient restoration of the matrix, the cells in the deep zone flow into the ones undergoing autophagy, apoptosis, and terminal differentiation while the cells in the superficial zone are promoted to differentiate to supply the loss of the deep zone cells. At the meantime, the bone marrow stromal cells are stimulated to bone formation in the subchondral cortical region which is uncoupled with the sites of the osteoclast-mediated resorption process that is predominantly observed at the subchondral trabecular bone region. Overall, the thickening and stiffening osteochondral interface, due greatly to the enhanced endochondral ossification in deep zone cartilage, should be a central pathological process that links with cartilage decay and subchondral bone remodelling in OA joints. The residual chondrocytes locating in the cartilage superficial zone have the progenitor-like qualities that can proliferate, and also differentiate into the deep zone chondrocytes, thus should be critical in progression and rehabilitation of TMJ-OA.

[One case report of pneumoconiosis in porcelain teeth workers].

Porcelain tooth technology is widely used in the treatment of oral diseases, but there are few reports on the possible occupational hazard factors in the process of porcelain tooth production. Porcelain teeth production will produced a large amount of silica dust and metal dust during the grinding process. The technical workers who have been engaged in this work for a long time are very prone to pneumoconiosis due to their poor personal protection awareness. This paper analyzed the clinical data of a pneumoconiosis patient engaged in porcelain tooth making, and analyzed the possible occupational hazard factors in the process of porcelain teeth production, so as to improve the understanding of relevant enterprises, technical workers and medical personnel on the disease and reduce the risk of porcelain teeth production workers suffering from pneumoconiosis.

The antibiofilm and collagen-stabilizing effects of proanthocyanidin as an auxiliary endodontic irrigant.

AIM: To evaluate the antibiofilm effect of proanthocyanidin (PA) solution as an irrigant against Enterococcus faecalis (E. faecalis) and its influence on the mechanical properties and biodegradation resistance of demineralized root dentine. METHODOLOGY: Enterococcus faecalis were introduced into human root dentine tubules by a serial centrifugation method and grown for 1 week. Dentine blocks infected with 1-week-old E. faecalis biofilms were treated with the following irrigants: sterile water (control), 2% chlorhexidine (CHX), 2% PA, 5% PA and 10% PA. After treatment, the live and dead bacteria proportions within E. faecalis biofilms were analysed using confocal laser scanning microscopy. To evaluate the biostability of fully demineralized dentine treated by the aforementioned irrigants, the elastic modulus and hydroxyproline release of human dentine incubated in collagenase solution were tested at baseline, after irrigant treatment and after biodegradation, respectively. Furthermore, the surface chemical bond of demineralized dentine collagen treated by various irrigants was characterized by X-ray photoelectron spectroscopy (XPS). Statistical analysis was performed using one-way anova and Tukey's post hoc multiple comparisons with the significance level at 5%. RESULTS: The proportion of dead E. faecalis volume was significantly higher in the PA and CHX groups than that in the control group (P < 0.05). PA irrigation significantly increased the mechanical properties of demineralized dentine (P < 0.05), and the effect was enhanced with increasing PA concentration. CHX and PA groups had significantly less elasticity loss and hydroxyproline release (P < 0.05). The biomodification of dentine collagen by PA was verified by increased C-O/C-N peak percentage under C1s and C-O peak percentage under O1s narrow-scan XPS spectra. CONCLUSIONS: Proanthocyanidin killed E. faecalis within biofilms and enhanced the biostability of the collagen matrix of demineralized root dentine. It might be used as an auxiliary endodontic irrigant with antibiofilm and collagen-stabilizing effects.

Hematopoietic and lymphatic cancers in patients with periodontitis: a systematic review and meta-analysis.

BACKGROUND: Numerous studies have explored the correlation of periodontal disease (PD) with risk of hematopoietic and lymphatic cancers, but the findings were inconsistent. Therefore, we did a meta-analysis to ascertain the correlation of PD with risk of incident hematopoietic and lymphatic cancers. MATERIAL AND METHODS: The authors searched relevant studies in databases (PubMed, Web of Science, and MEDLINE). The summary relative risk (RR) along with 95% confidence interval (CI) was calculated by use of random or fixed effects models. RESULTS: Six studies were included in qualitative synthesis. The pooled analysis revealed that PD was significantly associated with an increased risk of hematopoietic and lymphatic cancers (RR = 1.17; 95% CI = 1.07-1.27; P = 0). Stratified analysis showed the association of PD with hematopoietic and lymphatic cancers remained significant in the never smokers (RR = 1.28; 95% CI = 1.07-1.54; P = 0.007), and in the American population (RR = 1.17; 95% CI = 1.05-1.30; P = 0.003), respectively. CONCLUSION: Never smokers population and the American population with PD have a higher risk of developing hematopoietic and lymphatic cancers. PD might be considered as a risk factor for hematopoietic and lymphatic cancers.

Biodegradation of polyvinyl alcohol by different dominant degrading bacterial strains in a baffled anaerobic bioreactor.

Polyvinyl alcohol (PVA) is the main pollutant in printing and dyeing wastewaters. This pollutant exhibits great demand, poor biodegradability and refractory degradation. In this study, PVA wastewater treatment experiments were conducted in a stably operating baffled anaerobic bioreactor (ABR) by using simulated PVA wastewater. The PVA degradation pathway and mechanism of the mixed dominant PVA-degrading bacterial strains were identified through the analysis of their degradation products. From the results, we inferred that PVA was degraded in a stepwise process under the synergistic action of different extracellular and intracellular enzymes produced by the mixed dominant PVA-degrading bacterial strains. In this process, PVA was first degraded into ketones, fatty acids and alcohols. It was then regenerated into acetic acid, hydrogen and carbon dioxide. Finally, these substances could be further utilized by methanogens. PVA was thus degraded completely. This study may serve as a reference for future works on the degradation of PVA in the ecological environment. It may also guide the sustainable development of PVA.

The potential of salivary biomarkers for predicting the sensitivity and monitoring the response to nonsurgical periodontal therapy: A preliminary assessment.

BACKGROUND AND OBJECTIVE: The response to nonsurgical periodontal treatment varied among patients. This study assessed the potential of salivary biomarkers for predicting the sensitivity and monitoring the response to nonsurgical periodontal therapy. MATERIAL AND METHODS: This study recruited 34 participants with severe chronic periodontitis (the test group) and 20 participants without periodontal destruction in any teeth (the control group) from September 6, 2013 to August 25, 2017. Participants in the test group received nonsurgical periodontal therapy and were further divided into 2 subgroups of 17 low responders and 17 high responders, based on probing depth reduction. Clinical periodontal parameters were recorded, and saliva samples were harvested before and after nonsurgical periodontal therapy. Salivary biomarkers, including interleukin (IL)-1beta (IL-1ß), IL-1 receptor antagonist (IL-1ra), IL-6, IL-8, platelet-derived growth factor-BB, vascular endothelial growth factor, MMP-8, MMP-9, C-reactive protein, and lactoferrin were analyzed. RESULTS: Compared with participants in the control group, participants in the test group had significantly greater periodontal pocket depth, clinical attachment level, and salivary IL-1ß and MMP-8 levels, and all of these parameters were significantly reduced after nonsurgical periodontal therapy. The pretreatment levels of IL-1ß, MMP-8, and lactoferrin were significantly higher in participants of the high-responder subgroup than participants of the low-responder subgroup.Based on the analysis from a dichotomous table, MMP-8 and lactoferrin showed odds ratios of 5.76, with 71% sensitivity and 71% specificity, and statistical significance (P = .02) for discriminating between the high- and low-responder subgroups. CONCLUSION: Salivary IL-1ß and MMP-8 might be useful for diagnosing periodontitis and monitoring the recovery of periodontitis following nonsurgical periodontal therapy. MMP-8 and lactoferrin showed potential for predicting the sensitivity to the treatment.

Periodontal ligament-like tissue regeneration with drilled porous decalcified dentin matrix sheet composite.

OBJECTIVE: In this study, we constructed a composite by combining the human dental follicle cell sheet and a manual drilled porous decalcified dentin matrix that was used to construct ectopic tissue-engineered periodontal ligament-like tissues in renal capsules of nude mice. MATERIALS AND METHODS: Human dental follicle cells were harvested from human lower third molars and then embedded into a temperature-sensitive culture dish. These cells were then placed into frozen porous decalcified dentin matrix sheets and induced by 50 g/ml ascorbic acid. This established a "sandwich structure" in vitro implant that was placed in nude mice under the renal capsule. The mice were sacrificed at 4 and 8 weeks after implantation, and the implants were assessed after haematoxylin-eosin staining, Masson staining and immunohistochemical staining. RESULTS: The experimental group showed a fibre structure between the dentin and HA-TCP after 4 weeks. After 8 weeks, the collagen fibres increased, and the direction was perpendicular to the dentin. Immunohistochemistry showed positive staining in the osteopontin and periostin. CONCLUSION: The composite can induce ectopic bone and fibre formation, and the fibre had a certain directionality. Besides, the composite can maintain the stability of the periodontal ligament width.

[Salivary microbiome in people with obesity: a pilot study].

OBJECTIVE: To investigate the characterization of the salivary microbiome in people with obesity and the differences in microbial composition, gene function and metabolic pathways of salivary microbiome between people with obesity and normal weight controls. METHODS: The study was carried out in people with obesity and age- and sex-matched normal weight controls. None of these selected participants had the systemic disease, oral mucosal disease or periodontal disease. Unstimulated saliva samples were collected and oral examination was conducted. DNAs from saliva samples were extracted and sequenced in an Illumina NextSeq 500 platform. Community composition, linear discriminant analysis of taxonomic differences,gene prediction, gene set construction and annotation of gene function were performed. RESULTS: The classified bacterial reads of the samples were 2 630 428 for each sample. A total of 11 phyla, 19 classes, 26 orders, 41 families, 62 genera and 164 species were detected ultimately. All samples had the same predominant phyla (Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria and Fusobacteria). There were statistical differences between the groups at the class, order, family, genus and species levels. At the class level, Negativicutes and Erysipelotrichia were more abundant in the obesity group, while Flavobacteriia and Bateroidetes dominated in normal weight group (P<0.05). At the species level, 16 showed significant differences in relative abundance among the groups, in which Prevotella melaninogenica,Prevotella salivae,Solobacterium moorei and Atopobium parvulum ware more abundant in the obesity group, whereas Streptococcus sanguinis dominated in normal weight group (P<0.05). The people with obesity had a higher number of salivary microbial genes (P<0.05). We produced statistics on gene prediction and found salivary microbiome of obesity group had a higher number of genes (P < 0.05). Genes associated with the pathways of metabolism and environmental information processing and human diseases were significantly enriched in the saliva samples of people with obesity (P < 0.01). CONCLUSION: Significant differences were seen in composition, gene function and metabolic pathways of salivary microbiome between people with obesity and normal weight people. We hope to go on further study with larger sample size in the near future.

[Impact of aortic root morphology on the implantation depth of aortic valve prosthesis during trans-catheter aortic valve replacement in patients with native bicuspid aortic valve stenosis].

Objective: To investigate the impact of aortic root morphology on the implantation depth of aortic valve prosthesis during trans-catheter aortic valve replacement (TAVR) in bicuspid aortic valve patients. Methods: Clinical data of 40 patients with native bicuspid aortic valve stenosis who underwent TAVR using the self-expandable prosthesis (the Venus A-valve) from 2014 to 2017 in Fuwai Hospital was retrospectively analyzed. The patients were divided into non-deep implantation group (implant depth ≤10 mm by instant angiogram after implantation,29 cases) and deep implantation group (implant depth> 10 mm by instant angiogram after implantation,11 cases).Pre-procedural aortic root characteristics (e.g. calcification, angle and dimensions) were assessed by CT. The impact of aortic root morphology on the implantation depth and clinical outcomes were also evaluated. Results: The age was (75.1±5.9) years with equal representation from the raphe-type and non-raphe type (52.5%(21/40) and 47.5%(19/40)).The bigger aorta angle ((56.5±4.5)° vs. (47.4±9.4)°, P=0.004),more frequent mild-calcification (HU850, <200 mm(3)) or severe-calcification(HU850, >1 000 mm(3)) of aortic leaflets (7/11 vs. 4/29, P=0.006), as well as higher ratio of left ventricular outflow tract perimeter to annulus perimeter ((109.2±7.5)% vs. (101.5±6.5)%, P=0.004) were found in the deep implantation group compared to the non-deep implantation group. The new in-hospital onset of bundle-branchheart-block or atrioventricular block conduction disturbance rate was higher in the deep implantation group than in the non-deep implantation group (6/11 vs. 2/29, P=0.030).Left ventricular ejection fraction was similar between deep implantation group and non-deep implantation group at baseline((49.9±8.9)% vs. (55.8±10.4)%, P=0.117), and was significantly lower in the deep implantation group than in the non-deep implantation group at 30 days after implantation ((51.6±12.8)% vs. (60.9±8.1)%, P=0.020). Conclusion: Aortic root morphology of bicuspid aortic valve patients is associated with implantation depth of the prosthesis during TAVR, which affects the conduction system and left ventricular function during and post TAVR.

Increased expression of triggering receptor expressed on myeloid cells 1 and 2 in inflamed human gingiva.

BACKGROUND AND OBJECTIVE: Periodontitis is an infectious disease in which the host immune and inflammatory responses play essential roles in resistance to bacterial infection, as well as the induction of tissue destruction if the immune response is dysregulated. The triggering receptor expressed on myeloid cells (TREMs) modulates inflammatory and innate immune signaling. TREM-1 is considered as an amplifier of the immune response, while TREM-2 is a negative regulator that has yet to be explored in periodontal disease before. We hypothesized that TREMs participated in the innate immune responses during the pathogenesis of periodontitis. Therefore, the aim of this study was to evaluate TREM-1 and TREM-2 expression in the gingival tissues from patients with chronic periodontitis and healthy subjects as well as their correlation with clinical periodontal parameters. This study is the first to identify TREM-2 in periodontal tissue, as well as the protein expression changes of TREM-1 and TREM-2 in periodontal tissues. MATERIAL AND METHODS: Gingival tissue sections were collected from 31 healthy subjects and 53 patients with chronic periodontitis. Immunohistochemistry and quantitative real-time polymerase chain reaction were employed to evaluate the protein and mRNA expression of these receptors in gingival tissues. The recorded clinical parameters were probing depth, clinical attachment loss, plaque index and bleeding on probing. RESULTS: In addition to myeloid cells in gingival connective tissues, TREM-1 and TREM-2 were also found expressed in gingival epithelial cells. In particular, TREM-1 was detected in almost all gingival epithelium from both healthy and inflamed biopsies. The expression levels of TREM-1 and TREM-2 were significantly increased in the periodontitis group compared to the healthy group. Increased levels of these receptors are to be positively correlated with site-specific periodontal parameters. CONCLUSION: The increased expression of TREM-1 and TREM-2 levels in periodontitis may confer diagnostic and potential therapeutic targets as well as indicating their association with the clinical severity of the disease.

Marsupialization facilitates movement of the cystic lesion-associated deeply impacted mandibular third molar in spite of its mature roots.

BACKGROUND: The odontogenic cystic lesions happened in the angle and ramus region are frequently associated with impacted mandibular third molars. The treatment plan was difficult to work out for the huge cystic lesions with deeply impacted third molars, since the enucleation with simultaneously removing the deeply impacted teeth may cause serious complications. Therefore, the marsupialization of the cystic lesions followed by enucleation with tooth removal has also been advocated. The aim of this study was to explore the movement of cystic lesion-associated deeply impacted mandibular third molars (IMTM) after marsupialization. MATERIALS AND METHODS: Between July 2009 and December 2015, patients who had mandibular cystic lesion associated with IMTM and underwent marsupialization followed by enucleation with tooth extraction were included in our retrospective study. The clinical and pathological data was collected. The distance and direction of movement of the IMTM after marsupialization was measured on panoramic radiograph and computed tomography. RESULTS: Four male and six female patients whose ages ranged from 14 years to 67 years were enrolled in this study. Among the all impacted molars, there were 3 cases with mature roots. After marsupialization, all the cystic lesions shrunk and all impacted teeth moved toward the bony windows, and the distance of tooth movement were from 8.3mm to 12.1mm. The complications included swelling and pain, while no numbness of the ipsilateral lower lip was happened. CONCLUSIONS: Marsupialization can promote the movement of impacted teeth with or without mature roots, and may be an optimal treatment approach for the huge posterior mandibular cystic lesions with deeply impacted third molar.

Systemic administration of strontium or NBD peptide ameliorates early stage cartilage degradation of mouse mandibular condyles.

OBJECTIVE: To determine whether mandibular condylar cartilage degradation induced by experimentally abnormal occlusion could be ameliorated via systemic administration of strontium or NBD peptide. METHODS: Six-week-old female C57BL/6J mice were used. From the seventh day after mock operation or unilateral anterior crossbite (UAC) treatment, the control and UAC mice were further respectively pharmacologically treated for 2 weeks or 4 weeks of saline (CON + Saline and UAC + Saline groups), SrCl2 (CON + SrCl2 and UAC + SrCl2 groups) or NBD peptide (CON + NBD peptide and UAC + NBD peptide groups). Changes in condylar cartilage and subchondral bone were assessed 21 and 35 days after mock operation or UAC procedure by histology and micro-CT. Real-time PCR and/or immunohistochemistry (IHC) were performed to evaluate changes in expression levels of col2a1, aggrecan, ADAMTS-5, tnf-α, il-1ß, nfkbia, nuclear factor-kappaB phospho-p65 in condylar cartilage, and rankl/rank/opg in both condylar cartilage and subchondral bone. RESULTS: Cartilage degradation with decreased col2a1 and aggrecan expression, and increased ADAMTS-5, tnf-α/il1-ß, nfkbia and NF-κB phospho-p65 was observed in UAC + Saline groups. Subchondral bone loss with increased osteoclast numbers and decreased opg/rankl ratio was found in UAC + Saline groups compared to age-match CON + Saline groups. Cartilage degradation and subchondral bone loss were reversed by treatment of SrCl2 or NBD peptide while the same dosage in control mice induced few changes in condylar cartilage and subchondral bone. CONCLUSIONS: The results demonstrate reverse effect of systemic administration of strontium or NBD peptide on UAC-induced condylar cartilage degradation and subchondral bone loss.

Isolation, identification and fibrolytic characteristics of rumen fungi grown with indigenous methanogen from yaks (Bos grunniens) grazing on the Qinghai-Tibetan Plateau.

AIM: To obtain co-cultures of anaerobic fungi and their indigenously associated methanogens from the rumen of yaks grazing on the Qinghai-Tibetan Plateau and investigate their morphology features and ability to degrade lignocellulose. METHODS AND RESULTS: Twenty fungus-methanogen co-cultures were obtained by Hungate roll-tube technique. The fungi were identified as Orpinomyces, Neocallimastix and Piromyces genera based on the morphological characteristics and internal transcribed spacer 1 sequences analysis. All methanogens were identified as Methanobrevibacter sp. by 16S rRNA gene sequencing. There were four types of co-cultures: Neocallimastix with Methanobrevibacter ruminantium, Orpinomyces with M. ruminantium, Orpinomyces with Methanobrevibacter millerae and Piromyces with M. ruminantium among 20 co-cultures. In vitro studies with wheat straw as substrate showed that the Neocallimastix with M. ruminantium co-cultures and Piromyces with M. ruminantium co-cultures exhibited higher xylanase, filter paper cellulase (FPase), ferulic acid esterase, acetyl esterase activities, in vitro dry matter digestibility, gas, CH4 , acetate production, ferulic acid and p-coumaric acid releases. The Neocallimastix frontalis Yak16 with M. ruminantium co-culture presented the strongest lignocellulose degradation ability among 20 co-cultures. CONCLUSIONS: Twenty fungus-methanogen co-cultures were obtained from the rumen of grazing yaks. The N. frontalis with M. ruminantium co-cultures were highly effective combination for developing a fermentative system that bioconverts lignocellulose to high activity fibre-degrading enzyme, CH4 and acetate. SIGNIFICANCE AND IMPACT OF THE STUDY: The N. frontalis with M. ruminantium co-cultures from yaks grazing on the Qinghai-Tibetan Plateau present great potential in lignocellulose biodegradation industry.

Knowledge, attitudes and practices surrounding occupational blood-borne pathogen exposure amongst students in two Chinese dental schools.

OBJECTIVE: To investigate the knowledge, attitudes and practices surrounding occupational blood-borne pathogen exposure amongst dental students at two Chinese dental schools, as well as important factors that are associated with their career choice and attitudes towards infected patients. SUBJECT AND METHODS: The study was conducted using a student self-administered questionnaire from March to June 2013 at two Chinese dental schools. Chi-square tests and multivariable logistic regression were used to compare the categorical variables and identify the variables related to attitudes. RESULTS: One hundred and seventy-one students answered the questionnaire (response rate 83%). Most participants had incomplete knowledge about occupational exposure and participants' compliance with the infection control programme during routine clinical work was low. Fifty-six participants (34%) experienced at least one occupational exposure, but only one reported the incident. Percutaneous injuries and mucous membrane exposures were the main causes for exposure. Protection of the eyes and post-exposure management were inadequate. According to most participants, they had received insufficient education. Their concerns about the risk of infectious professional exposure would influence their career choice and approach to patients. Only 14% and 26% of the participants were willing to treat human immunodeficiency virus- and hepatitis B virus-infected patients, respectively. CONCLUSIONS: More effective education on prevention and management is required for dental students to reduce the harm caused by occupational exposure. It is important to ensure dental students' knowledge and understanding before allowing them to enter clinical training.

[Transpalatal modified Le Fort I osteotomy for correction of maxillary hypoplasia in cleft lip and palate patients: a preliminary clinical application].

OBJECTIVE: To evaluate the surgical corrective results of maxillary hypoplasia in patients with cleft lip and palate withtranspalatal modified Le Fort I osteotomy. METHODS: In the study, 11 patients (4 women, and 7 men) with maxillary hypoplasia secondary to cleft lip and palate underwent transpalatal modified Le Fort I osteotomy at Peking University School of Stomatology from Jan. 2012 to Dec. 2013,with the mean age of 21 years ( from 18 to 27 years), Bilateral sagittal split ramus osteotomy (BSSRO)and genioplasty were performed simultaneously in 9 of them for better appearance and functional occlusion. Lateral cephalometric radiographs were taken and traced before surgery, immediately after surgery and 6 months after surgery. The position of subspinale (A) on horizontal direction, the angle of sella-nasion-subsipmale (SNA) and the angle of sella-nasion-supramental (SNB) were collected and analyzed to evaluate the results. RESULTS: All the patients were uneventful with transpalatal modified Le Fort I osteotomy. All of them had a better profile and a satisfactory occlusionafter operation.The position of A was moved forward (6.6±1.1) mm on average in horizontal direction when surgery was completed, and maintained (6.0±1.2) mm on average 6 months after surgery. The average of SNA was 75.9°±2.8° before surgery,81.6°±8.6° immediately after surgery, and maintained 81.0°±2.6° 6 months after surgery. The average of SNB was 82.6°±3.7° before surgery, 78.0°±2.4° immediately after surgery, and maintained 78.5°±2.4° 6 months after surgery. CONCLUSION: The maxillary hypoplasia in cleft lip and palate patients can be successfully corrected with transpalatal modified Le Fort I osteotomy and the functional occlusion can be achieved simultaneously. The effect of deformity correction was satisfactory. Transpalatal modified Le Fort I osteotomy can move maxilla more sufficiently, especially applicable for the patient with severe palatal scars preoperatively.

[Determination of perfluorosulfonate and perfluorocarboxylate precursors in eggs by ultra-highperformance liquid chromatography-mass spectrometry].

OBJECTIVE: To develop a method for the determination of 11 perfluorosulfonate and perfluorocarboxylate precursors in eggs using ultra-high performance liquid chromatography-tandem quadruple mass spectrometry (UPLC-MS/MS). METHODS: The target compounds of egg were extracted with 100 mmol/L NaOH-acetonitrile /water(90∶10, V/V) by ultrasonic. Then the extract was purified by solid phase extraction (Waters Oasis(@) WAX 6cc) and then eluted with 9% NH4OH in methanol. The target compounds were separated on a Waters ACQUITY(TM) BEH (18)C column (50 mm × 2.1 mm, 1.7 µm) and detected by negative electrospray ionization (ESI(-)) mass spectrometry in multiple reaction monitoring mode (MRM). All compounds were quantified with internal standards. The accuracy, precision and the limits of detection and quantification of the method were evaluated. Then we detected 7 different egg samples from the market. RESULTS: The average recoveries for the eleven precursors at 3 levels were 74.09%-116.82% and the relative standard deviations were 2.37%-13.62%. The limits of detection (LOD) of the method were in the range of 0.06-1.50 pg/g (wet weight) and the limits of quantification (LOQ) were in the range of 0.15-3.00 pg/g (wet weight). And 5 target compounds were detected in the 7 market samples. 6:2 fluorotelomer sulfonate (6:2 FTS) was detected in all of samples with the concentrations of 1.67-3.11 pg/g. 6:2 fluorotelomer unsaturated acid (FHUEA) and 6:2 disubstituted polyfluoroalkyl phosphate ester (6:2 diPAP) were detected in 6 samples and the concentrations were

The association between the RAGE G82S polymorphism, sRAGE and chronic periodontitis in Taiwanese individuals with and without diabetes.

BACKGROUND AND OBJECTIVE: The present study investigated the association between the RAGE G82S polymorphism, the plasma levels of sRAGE and chronic periodontitis in subjects with and without diabetes mellitus (DM). MATERIAL AND METHODS: A total of 230 patients with DM and 264 non-DM participants were recruited for this study. Genotyping of the RAGE G82S polymorphism was accomplished using polymerase chain reaction-restriction fragment length polymorphism, and associations were analyzed with the chi-squared test and logistic regression analysis. RESULTS: In the non-DM group, the chi-squared test showed that the frequency distributions of the G82S polymorphism were significantly different between chronic periodontitis and non-chronic periodontitis subjects (χ(2) = 8.39, p = 0.02). A multivariate logistic regression model showed that the (G82S + S82S) genotypes were associated with a significantly increased risk of chronic periodontitis development compared to the G82G genotype (adjusted odds ratio = 2.06, 95% confidence interval: 1.08-4.07). In the DM group, there was no association between the G82S polymorphism and chronic periodontitis development when a multivariate logistic regression was performed. Plasma levels of sRAGE were significantly higher in subjects with the G82G genotype compared to those with the (G82S + S82S) genotypes in both the non-DM (856.6 ± 332.0 vs. 720.4 ± 311.4 pg/mL, p = 0.003) and DM groups (915.3 ± 497.1 vs. 603.5 ± 298.3 pg/mL, p < 0.0001). However, there was no difference in plasma sRAGE levels between chronic periodontitis and non-chronic periodontitis subjects in both the DM and non-DM groups. Moreover, when the subjects were further sub-divided by the G82S polymorphism, the difference in plasma levels of sRAGE between chronic periodontitis and non-chronic periodontitis subjects in the DM and non-DM groups remained statistically insignificant. CONCLUSIONS: The present study revealed that the RAGE G82S polymorphism was associated with chronic periodontitis in the non-DM group but not in the DM group. Our results also showed that the plasma levels of sRAGE were significantly higher in subjects with the RAGE G82G genotype, and this correlation was not affected by the presence of chronic periodontitis in the DM and non-DM groups.