Decellularized matrix could affect the proliferation and differentiation of periodontal ligament stem cells in vitro.

OBJECTIVE AND BACKGROUND: Recently, decellularized matrix (DCM) is considered as a new biomaterial for tissue regeneration. To explore the possible application of DCM in periodontal regeneration, the effect of DCM from three different cells on the proliferation and differentiation of human periodontal ligament stem cells (PDLSCs) was investigated. METHODS: DCM derived from human periodontal ligament cells (PDLCs), dental pulp cells (DPCs), and gingival fibroblasts (GFs) were fabricated using Triton X-100/NH4 OH combined with DNase I. Allogeneic PDLSCs were cultured on PDLC-DCM, DPC-DCM, and GF-DCM, respectively. The proliferative capacity of PDLSCs was evaluated by PicoGreen assay kit. The expression of alkaline phosphatase (ALP), runt-related transcription factor-2 (RUNX2), osteocalcin (OCN), collagen I (COL1), periostin (POSTN), and cementum protein 1 (CEMP1) were detected by qRT-PCR and western blotting. RESULTS: PDLC-DCM, DPC-DCM, and GF-DCM had similar and integrated networks of extracellular matrix, as well as significantly decreased DNA content. Compared with control group in which PDLSCs were directly seeded in culture plates, PDLC-DCM, DPC-DCM, and GF-DCM promoted the proliferation of re-seeded PDLSCs. Additionally, PDLSCs on DCM exhibited higher mRNA and protein expression levels of ALP, RUNX2, OCN, and COL1. The expression of POSTN in PDLC-DCM group was significantly higher than control group at both mRNA and protein levels. CONCLUSIONS: PDLC-DCM, DPC-DCM, and GF-DCM could enhance the proliferation of PDLSCs. PDLC-DCM facilitated osteogenic differentiation and periodontal ligament differentiation of PDLSCs, while DPC-DCM and GF-DCM promoted osteogenic differentiation.

Multifunctional carbonized nanogels to treat lethal acute hepatopancreatic necrosis disease.

BACKGROUND: Shrimp aquaculture has suffered huge economic losses over the past decade due to the outbreak of acute hepatopancreatic necrosis disease (AHPND), which is mainly caused by the bacteria Vibrio parahaemolyticus (V. parahaemolyticus) with the virulence pVA1 plasmid, which encodes a secretory photorhabdus insect-related (Pir) toxin composed of PirA and PirB proteins. The Pir toxin mainly attacks the hepatopancreas, a major metabolic organ in shrimp, thereby causing necrosis and loss of function. The pandemic of antibiotic-resistant strains makes the impact worse. METHODS: Mild pyrolysis of a mixture of polysaccharide dextran 70 and the crosslinker 1,8-diaminooctane at 180 â„ƒ for 3 h to form carbonized nanogels (DAO/DEX-CNGs) through controlled cross-linking and carbonization. The multifunctional therapeutic CNGs inherit nanogel-like structures and functional groups from their precursor molecules. RESULTS: DAO/DEX-CNGs manifest broad-spectrum antibacterial activity against Vibrio parahaemolyticus responsible for AHPND and even multiple drug-resistant strains. The polymer-like structures and functional groups on graphitic-carbon within the CNGs exhibit multiple treatment effects, including disruption of bacterial membranes, elevating bacterial oxidative stress, and neutralization of PirAB toxins. The inhibition of Vibrio in the midgut of infected shrimp, protection of hepatopancreas tissue from Pir toxin, and suppressing overstimulation of the immune system in severe V. parahaemolyticus infection, revealing that CNGs can effectively guard shrimp from Vibrio invasion. Moreover, shrimps fed with DAO/DEX-CNGs were carefully examined, such as the expression of the immune-related genes, hepatopancreas biopsy, and intestinal microbiota. Few adverse effects on shrimps were observed. CONCLUSION: Our work proposes brand-new applications of multifunctional carbon-based nanomaterials as efficient anti-Vibrio agents in the aquatic industry that hold great potential as feed additives to reduce antibiotic overuse in aquaculture.

Efficacy of nano-carbonate apatite dentifrice in relief from dentine hypersensitivity following non-surgical periodontal therapy: a randomized controlled trial.

BACKGROUND: Dentine hypersensitivity (DH) could occur or intensify after non-surgical periodontal therapy because of the exposure of dentine tubules, but currently no gold standard exists to treat DH. It has been demonstrated that nano-sized particles presented potential for dentine tubules blocking and remineralization. This randomized controlled trial aimed to investigate the efficacy of dentifrice containing nano-carbonate apatite (n-CAP) in reducing dentine hypersensitivity (DH) after non-surgical periodontal therapy. METHODS: 48 periodontitis patients with DH were included in this clinical trial. After non-surgical periodontal therapy, patients included were randomized to test and control group and the respective dentifrices were applied at chairside, after which they were instructed to brush teeth with the allocated dentifrices twice a day at home. Periodontal parameters were recorded at baseline and the last follow-up. DH was measured by air-blast test and recorded by visual analogue scale (VAS) and Schiff sensitivity scale at baseline, after polishing (0 week) and 2/4/6 weeks. RESULTS: 45 participants completed the follow-up. Periodontal parameters were improved and comparable between groups. Significant reduction in DH was observed in both groups at all time-points compared to baseline in terms of VAS and Schiff score. The test group achieved significantly greater relief from hypersensitivity compared with the control group after 4-week at-home use (for change of VAS, test group: 2.27 ± 2.47 versus control group: 1.68 ± 2.24, p = 0.036; for change of Schiff, test group: 0.94 ± 0.92 versus control group: 0.61 ± 0.83, p < 0.001). The 6-week results showed borderline significance between groups in terms of change of Schiff (p = 0.027) and no significance in terms of change of VAS (p = 0.256). CONCLUSIONS: Home-use of n-CAP based dentifrice had some benefit on alleviation of DH following non-surgical periodontal therapy after 4 weeks compared to the control product. TRIAL REGISTRATION: Chinese Clinical Trials Registry (No. ChiCTR-IPR-17011678, http://www.chictr.org.cn/, registered 16 June, 2017).

Long-term stability of root coverage procedures for single gingival recessions: A systematic review and meta-analysis.

AIM: To evaluate the long-term (≥2 years) stability of root coverage procedures for single gingival recessions. MATERIALS AND METHODS: A complete literature search was performed up to July 2018. Randomized controlled trials (RCTs) following ≥2 years were selected. Primary outcomes were complete root coverage (CRC) and mean root coverage (MRC). Secondary outcomes were width of keratinized tissue (KTW) and patient-centred parameters. Meta-analysis was conducted when possible. RESULTS: A total of fifteen RCTs were included. The results demonstrated significantly higher MRC in short-term than long-term after coronally advanced flap (CAF; 7.29%, p = 0.006). When CAF combined with connective tissue graft (CTG), no significant difference was observed in CRC or MRC for short-term versus long-term (1.00, p = 0.97; 2.35%, p = 0.09), and it resulted in better long-term efficacy than CAF alone in terms of CRC (0.69, p = 0.0006) and KTW (-0.63 mm, p = 0.04). For CAF plus enamel matrix derivative, the meta-analysis showed no significant difference between the short-term and long-term results of CRC (1.26, p = 0.21). CONCLUSIONS: CAF alone could result in decreased postoperative percentage of root coverage with time. CAF + CTG could maintain long-term stability and result in better root coverage outcomes than CAF.

Efficacy of xenogeneic collagen matrix in the treatment of gingival recessions: A systematic review and meta-analysis.

OBJECTIVES: This review aims to evaluate the efficacy of xenogeneic collagen matrix (XCM) for the treatment of single or multiple gingival recessions in terms of clinical parameters and patient-related outcomes. MATERIALS AND METHODS: Various electronic databases (The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, etc.) from 1966 to April 2018 and hand literatures were searched. Quality of the included studies was assessed through the Cochrane Collaboration's Risk of Bias tool. A meta-analysis was performed to calculate risk ratios and mean differences. RESULTS: Nine randomized controlled trials were included. The results revealed a higher percentage of mean root coverage (MRC) and a greater recession reduction (RecRed) for single recessions for the combination of coronally advanced flap (CAF) with XCM compared to CAF alone (n = 3; MD = 10.00%; 95%CI [3.56%; 16.43%]; p = 0.002) (n = 3; MD = 0.35 mm; 95%CI [0.10 mm; 0.60 mm]; p = 0.005). Comparing XCM with connective tissue graft (CTG), no significant differences were detected in MRC or RecRed for single and multiple recessions. CONCLUSIONS: The addition of XCM under CAF could improve MRC and RecRed at single tooth recessions. Initial data suggest that XCM shows promising results to improve the clinical efficacy of CAF for multiple recessions. In addition, XCM could be a valid alternative to CTG in terms of MRC and RecRed at both single and multiple recessions. Based on limited evidence, XCM may decrease postoperative morbidity and operation time compared to CTG.

[Pharmacokinetics of α-asarone after intranasal and intravenous administration with PLA-α-asarone nanoparticles].

PLA-α-asarone nanoparticles were prepared by using organic solvent evaporation method, and their in vivo distribution and brain targeting after intranasal administration were studied as compared with intravenous administration. The results showed that brain targeting coefficient of PLA-α-asarone nanoparticles after intranasal and intravenous administration was 1.65 and 1.16 respectively. The absolute bioavailability, brain-targeting efficiency and the percentage of nasal-brain delivery of PLA-α-asarone nanoparticles were 74.2%, 142.24 and 29.83%, respectively after intranasal administration. The results of fluorescence labeling showed that the fluorescent intensity of coumarin-6 in the brain tissue was the highest after intranasal administration of PLA-α-asarone fluorescent nanoparticles, achieving the purpose of brain-targeted drug delivery. The fluorescent intensity of coumarin-6 in liver tissue after intravenous administration of PLA-α-asarone nanoparticles was much higher than that after intranasal administration, indicating that intranasal administration of PLA-α-asarone nanoparticles could decrease drug-induced hepatotoxicity. In addition, the fluorescent intensity of coumarin-6 in lung tissue was weaker after intranasal administration, which solved the shortcomings of intranasal administration of α-asarone dry powder prepared by airflow pulverization method. In vivo studies indicated that PLA-α-asarone nanoparticles after intranasal administration had a stronger brain targeting as compared with intravenous administration.

Th17 and Th1 Lymphocytes Are Correlated with Chronic Periodontitis.

T cells are involved in the homeostasis of periodontal tissues and mediate bone loss in periodontitis, but the involvement of T-helper cells in chronic periodontitis (CP) in a Chinese population is still unclear. This study aimed to assess the distribution of peripheral and local T helper (Th17) and Th1 in CP. Sixty-eight patients with CP and 43 healthy controls were recruited from April 2012 to July 2014 at the Department of Stomatology, People's Hospital of Xinjiang Uygur Autonomous Region (China). The proportions of Th17 (CD3(+)CD4(+)IL-17(+)) and Th1 (CD3(+)CD4(+)IFN-γ(+)) T-cells in peripheral blood samples were assessed by flow cytometry. Immunohistochemistry was used to quantify interleukin-17 (IL-17) and interferon-gamma (IFN-γ) protein levels in gingival biopsy samples. mRNA levels of IL-17, IFN-γ RORγt, and T-bet in gingival biopsy samples were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The proportions of circulating Th17 cells and Th1 cells were both more abundant in CP patients than in controls (Th17: 1.05% ± 0.87% vs. 0.62% ± 0.49%, P < 0.01; Th1: 13.93% ± 7.94% vs. 8.22% ± 4.50%, P < 0.001). Positive correlations were obtained between the proportion of circulating Th17 cells and probing depth (PD) (r = 0.320, P = 0.001) and between the proportion of circulating Th1 cells and PD (r = 0.372, P < 0.001). IL-17 and IFN-γ protein levels in gingival biopsy samples were markedly increased in CP compared to controls (both P < 0.05). Relative IFN-γ, IL-17A, and T-bet mRNA levels in CP biopsies were higher compared to controls (all P < 0.05). These results suggest that elevated peripheral and local Th17 and Th1 cells might be involved in the pathogenesis of CP.

Cytokine levels in plasma and gingival crevicular fluid in chronic periodontitis.

PURPOSE: To evaluate the Th1/Th2/Th17 cytokine levels in plasma and gingival crevicular fluid (GCF) from chronic periodontitis patients and healthy controls. METHODS: The concentration of interleukin-2 (IL-2), IL-4, IL-6, IL-10, IL-17, TNF, and IFN-γ were determined using a flow cytometric multiplex immunoassay (CBA), and was compared between the periodontitis group and the healthy group. Spearman rho coefficient was used to correlate cytokines in GCF in the periodontitis group and the healthy group, respectively. RESULTS: Comparisons of two groups of Th1/Th2/Th17 cytokine levels in plasma and GCF showed no statistically significant differences (P > 0.05), except Th17 (IL-17) level in plasma that was higher in the periodontitis group than the healthy group (P < 0.05). A stronger correlation between IL-17/IL-4 and IL-17/IL-10 was observed in periodontitis patients than in healthy controls.

Possible socioeconomic and oral hygiene behavioural risk factors for self-reported periodontal diseases in women of childbearing age in a Chinese population.

PURPOSE: To examine the socioeconomic and behavioural risk factors for periodontal disease in women of childbearing age and evaluate the extent of public awareness of the association between oral health and pregnancy in China. MATERIALS AND METHODS: Cross-sectional data from 832 women (including 188 pregnant women) from Yuyao, Zhejiang Province were collected using a structured questionnaire. Demographic data were used to measure the participants' socioeconomic status. The questionnaire assessed knowledge and behaviours related to personal oral hygiene and utilisation of dental care services. Data were divided into pregnant and non-pregnant groups for multivariate logistic regression analysis. RESULTS: In total, 88.3% pregnant women and 74.2% non-pregnant women reported periodontal symptoms. Abnormal body mass index (BMI ≤ 18.5, odds ratio, OR = 0.76, 95% CI 0.27-0.97, P = 0.024; BMI ≥ 23.9, OR = 1.83, 95% CI 1.12-3.35, P = 0.035) was significantly associated with self-reported periodontal disease. Minimal mental stress (OR = 0.56, 95% CI 0.43-0.94, P = 0.028), high annual household income (OR = 0.69, 95% CI 0.17-0.82, P = 0.008), advanced oral hygiene aids (OR = 0.33, 95% CI 0.18-0.49, P < 0.001) and knowledge of the link between pregnancy and periodontal disease (OR = 0.57, 95% CI 0.33-0.96, P = 0.016) were associated with decreased incidence of self reported periodontal disease. CONCLUSIONS: A low socioeconomic background was correlated with the high incidence of self-reported periodontal disease among women of childbearing age in China. Education about primary oral health and equitable distribution of dental services might be expected to improve oral health in this specific population.

Transforming Adolescent Smiles: Correcting Skeletal Mandibular Retrusion and Bimaxillary Protrusion with Clear Aligners.

Maxillary protrusion combined with mandibular retraction is a highly prevalent but extremely complex maxillofacial deformity that can have a serious negative impact on patients' facial aesthetics and mental health. The traditional orthodontic treatment strategy often involves extracting 4 first premolars and conventional fixed techniques, combined with mini-implant screws, to retract the anterior teeth and improve facial protrusion. In recent years, an invisible orthodontic technique, without brackets, has become increasingly popular. However, while an invisible aligner has been used in some cases with reasonable results, there remain significant challenges in achieving a perfect outcome. This case report presents an adolescent patient with bimaxillary protrusion and mandibular retrognathia. Based on the characteristics of the invisible aligners and the growth characteristics of the adolescent's teeth and jawbone, we designed precise three-dimensional tooth movement and corresponding resistance/over-correction for each tooth, while utilizing the patient's jawbone growth potential to promote rapid development of the mandible, accurately and efficiently correcting bimaxillary protrusion and skeletal mandibular retrognathia. The patient's facial aesthetics, especially the lateral morphology, have been greatly improved, and various aesthetic indicators have also shown significant changes, and to the patient's great benefit, invasive mini-implant screws were not used during the treatment. This case highlights the advantages of using invisible aligners in adolescent maxillary protrusion combined with mandibular retraction patients. Furthermore, comprehensive and accurate design combined with good application of growth potential can also enable invisible orthodontic technology to achieve perfect treatment effects in tooth extractions, providing clinical guidance for orthodontists.

Clinical effect of Tip-Edge plus appliance in children with angle II(1) malocclusion.

The effects of Tip-Edge plus appliance in the treatment of Angle II(1) malocclusion and the mechanism were investigated. Fifty-two Angle II(1) children, aged from 12.3-14.2 years, with mandibular retrusion in permanent dentition were selected and treated with Tip-Edge plus appliance. Lateral cephalometric films taken before and after treatment were analyzed. The arithmetic mean and standard deviation were calculated for each variable. Paired t-test was performed to evaluate the significant treatment change. Results showed that the average treatment time was 16 months. Normal overjet and overbite were established with retroclination of upper incisors and proclination of lower incisors. U1-NA was decreased by 15.4° (P<0.01). ANB and Y axial angle were decreased significantly (P<0.05). Soft tissue measurements showed that FCA and UL-E were decreased dramatically (P<0.05), and LL-E was increased significantly (P<0.05). Remarkable soft tissue change was noted after the treatment and convex facial profile changed to the straight profile. In conclusion, Tip-Edge plus technique can quickly and efficiently correct anterior bite and lateral outlook.

Regeneration potential of decellularized periodontal ligament cell sheets combined with 15-deoxy-Δ12,14-prostaglandin J2 nanoparticles in a rat periodontal defect.

Periodontitis is a chronic inflammatory disease characterized by loss of attachment and destruction of the periodontium. Decellularized sheet, as an advanced tissue regeneration engineering biomaterial, has been researched and applied in many fields, but its effects on periodontal regeneration remain unclear. In this study, the biological properties of decellularized human periodontal ligament cell (dHPDLC) sheets were evaluated in vitro. Polycaprolactone/gelatin (PCL/GE) nanofibers were fabricated as a carrier to enhance the mechanical strength of the dHPDLC sheet. 15-deoxy-[Formula: see text]-prostaglandin J2 (15d-PGJ2) nanoparticles were added for anti-inflammation and regeneration improvement. For in vivo analysis, dHPDLC sheets combined with 15d-PGJ2 nanoparticles, with or without PCL/GE, were implanted into rat periodontal defects. The periodontal regeneration effects were identified by microcomputed tomography (micro-CT) and histological staining, and immunohistochemistry. The results revealed that DNA content was reduced by 96.6%. The hepatocyte growth factor, vascular endothelial growth factor, and basic fibroblast growth factor were preserved but reduced. The expressions or distribution of collagen I and fibronectin were similar in dHPDLC and nondecellularized cell sheets. The dHPDLC sheets maintained the intact structure of the extracellular matrix. It could be recellularized by allogeneic human periodontal stem ligament cells and retain osteoinductive potential. Newly formed bone, cementum, and PDL were observed in dHPDLC sheets combined with 15d-PGJ2 groups, with or without PCL/GE nanofibers, for four weeks post-operation in vivo. Bringing together all these points, this new construct of dHPDLC sheets can be a potential candidate for periodontal regeneration in an inflammatory environment of the oral cavity.

Longitudinal changes in mandibular arch posterior space in adolescents with normal occlusion.

INTRODUCTION: The purpose of this study was to investigate the changes of available mandibular space in the posterior dental arch of teenagers from 13 to 18 years old. METHODS: Longitudinal cephalograms of 28 adolescents (13 boys, 15 girls) with normal occlusion, selected from among 901 candidates, were taken annually from 13 to 18 years of age inclusively. Modified analyses with occlusal plane and occlusal plane perpendicular as reference planes were used to evaluate the changes of available space of the posterior mandibular arch. RESULTS: From 13 to 18 years of age, significant differences of mandibular posterior space were found among ages and sexes. The total increases of available space were 5.12 mm in the girls and 5.79 mm in the boys. For girls before age 16 and boys before age 17, the increased available space was contributed mainly by resorption of bone on the anterior border of the ramus. Mesial drift of the dental arch did not occur until the eruption of the third molars. The average available spaces increased 1.22 mm in girls less than age 16 and 1.45 mm in boys less than age 17 per side per year. CONCLUSIONS: The prediction of available space in the posterior mandibular arch should be based on age and sex.

Porphyromonas gingivalis-Induced NLRP3 Inflammasome Activation and Its Downstream Interleukin-1ß Release Depend on Caspase-4.

Background: Oral commensals contribute to microbe-host symbiosis in periodontal homeostasis, and Porphyromonas gingivalis (P. gingivalis) as the keystone pathogen critically accounts for the shift of symbiosis to dysbiosis and periodontal destruction. Nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome-mediated interleukin-1ß (IL-1ß) is significantly involved in periodontal diseases, and notably P. gingivalis enables to modulate the induction and expression of NLRP3. Whereas, the exact mechanism by which NLRP3 inflammasome is regulated in response to commensal and pathogenic bacteria remains unclear. Methods: To examine the expression of IL-1ß and NLRPs inflammasome in tissues with severe chronic periodontitis, and further investigate how Caspase-4-dependent non-canonical NLRP3 inflammasome pathways functioned during the interactions of Streptococcus mitis (S. mitis) and P. gingivalis with human THP-1 cells. Results: IL-1ß and NLRP3, NLRP6, NLRP12, and absent in melanoma 2 (AIM2) inflammasomes are highly expressed in gingival tissues with severe chronic periodontitis. In human THP-1 cells, P. gingivalis activates the synthesis and secretion of IL-1ß to higher levels than S. mitis. Importantly, NLRP3-, Caspase-1-, and Caspase-4-siRNA knockdown THP-1 cells treated with P. gingivalis exhibited a lower expression level of IL-1ß as compared to the control cells. In addition, silencing of either CASP4 or CASP1 can lead to a concurrent or reciprocal decrease in the expression of the other. Of note, the IL-1ß induction is not affected in the S. mitis-treated THP-1 cells with the silence of NLRP3, Caspase-1, and Caspase-4 genes. Conclusion: NLRP3/Caspase-4 and NLRP3/Caspase-1 dependent IL-1ß production may crucially contribute to the dysregulated immuno-inflammatory response in periodontal pathogenesis.

[Therapeutic effect analysis of skeletal class â ¢ malocclusion treatment by transmission straight wire technique].

OBJECTIVE: This study aimed to investigate the therapeutic effects and advantages of skeletal class Ⅲ malocclusion treatment by transmission straight wire technique. METHODS: Ninety-seven patients who received treatment for skeletal class Ⅲ malocclusion at the Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 2012 to January 2017 were selected for this retrospective study. All these patients refused surgery. They were divided into two groups in accordance with the type of skeletal malocclusion: mild-to-moderate skeletal malocclusion group (-4°≤ANB <0°) and severe skeletal malocclusion group (-8°≤ANB<-4°). Each of the two groups was divided further into two small groups in accordance with the technique used: T group (transmission straight wire technique) and M group (MBT technique). RESULTS: The crossbite of all 59 patients in the mild-to-moderate skeletal malocclusion group was successfully treated. The molars were classified as classⅠrelationship, and the facial profile improved. Significant differences were found in the values of U1/SN angle, L1/MP angle, and Lip-Diff between the T and M groups before and after the treatment (P<0.05). The extent of incisor root resorption was lighter in the T group than in the M group (P<0.05). In the severe skeletal malocclusion group, the crossbite of all 38 patients was cured or partially cured. Fourteen patients showed severe lower anterior teeth inclination (five in the T group and nine in the M group), and the profiles did not significantly improve. Significant differences were observed in the values of U1-NA value, U1/SN angle, L1-NB value, L1/MP angle, LLP, and Lip-Diff between the T and M groups before and after the treatment (P<0.05). The extent of incisor root resorption was lighter in the T group than in the M group (P<0.05). CONCLUSIONS: Relative to the MBT technique, the transmission straight wire technique has great advantages in improving facial profile, reducing the compensatory inclination of the upper and lower anterior teeth, and reducing the risk of root resorption in the treatment of skeletal class Ⅲ malocclusion.

Quantitative cervical vertebral maturation assessment in adolescents with normal occlusion: a mixed longitudinal study.

INTRODUCTION: The purpose of this study was to establish a quantitative cervical vertebral maturation (CVM) system for adolescents with normal occlusion. METHODS: Mixed longitudinal data were used. The subjects included 87 children and adolescents from 8 to 18 years old with normal occlusion (32 boys, 55 girls) selected from 901 candidates. Sequential lateral cephalograms and hand-wrist films were taken once a year for 6 years. The lateral cephalograms of all subjects were divided into 11 maturation groups according to the Fishman skeletal maturity indicators. The morphologic characteristics of the second, third, and fourth cervical vertebrae at 11 developmental stages were measured and analyzed. RESULTS: Three characteristic parameters (H4/W4, AH3/PH3, @2) were selected to determine the classification of CVM. With 3 morphologic variables, the quantitative CVM system including 4 maturational stages was established. An equation that can accurately estimate the maturation of the cervical vertebrae was established: CVM stage=-4.13+3.57xH4/W4+4.07xAH3/PH3+0.03x@2. CONCLUSIONS: The quantitative CVM method is an efficient, objective, and relatively simple approach to assess the level of skeletal maturation during adolescence.

[Artifacts from dental metal alloys in magnetic resonance imaging].

OBJECTIVE: To evaluate the artifact sizes at 3.0 T compared to at 1.5 T caused by three kinds of metallic dental materials, and to evaluate the influences of different magnetic resonance imaging (MRI) sequences on the artifact. METHODS: Samples of metal-ceramic crown of three kinds of dental materials (Ni-Cr alloy, Co-Cr alloy, and gold alloy) were placed in a cylindrical plastic vessel filled with agarose gel. Acrylic resin crown was used as control. Images were performed by means of 1.5 T and 3.0 T MRI apparatus with 4 different sequences commonly used in brain MRI sequences. Artifact diameter was calculated and compared quantitatively. A 4 x 4 x 2 factorial design was applied to determine the effects on the MRI artifact of different metal materials, different sequences, and different magnetic field strengths. RESULTS: ANOVA of factorial design showed that the influences of material, magnetic field strength, and sequence were all significantly different( materials: F = 124.796, df = 3, P = 0.000; magnetic field strength: F = 9.367, df = 1, P = 0.003; sequence: F = 3.020, df = 3, P = 0.036). Among the 3 kinds of alloys, the gold alloy produced the least artifact. Among the 4 imaging sequences, fast spin echo (FSE) produced the least artifact. The artifact sizes increased at 3.0 T compared to at 1.5T. Interactions among the 3 factors did not influence the artifacts significantly (P > 0.05). CONCLUSION: Selection of specific metal material and imaging sequence can minimize the metal artifacts in MRI. The increment of artifacts at 3.0 T is only by 10% compared to that at 1.5 T. But 3.0 T MRI system has great advantages, so it is eligible on patients with metal restoration.

[Effect of Porphyromonas gingivalis lipopolysaccharide on induced secretion of inflammatory cytokines by different cell lines].

OBJECTIVE: To determine the effect of Porphyromonas gingivalis lipopolysaccharide (LPS) on induced secretion of inflammatory cytokines by different cell lines. METHODS: LPS of P. gingivalis strain ATCC33277 (Pg-LPS) was extracted with phenol-water method, and identified by Limulus test and infrared spectrum analysis. KB, HGF-1 and THP-1 cells were treated with Pg-LPS of different concentrations and time duration, a commercial LPS of E.coli strain O111:B4 (E-LPS) was used as the control. TNF-alpha, IL-1beta, IL-6 and IL-8 levels in culture supernatants were measured by quantitative ELISA. RESULT: The minimal dosages of both Pg-LPS and E-LPS to solidify Limulus agents were 15 ng/ml and their infrared spectrums were similar. With the treatment of Pg-LPS or E-LPS, the TNF-alpha and IL-1beta levels secreted by HGF-1 cells were remarkably increased with a single perk (P<0.01) while a continuous enhancement of secretion by THP-1 cells was observed (P<0.01). Either Pg-LPS or E-LPS stimulated HGF-1 or THP-1 cells to continuously increase the secretion of IL-6 (P<0.01). Both Pg-LPS and E-LPS induced IL-8 secretion by THP-1 cells (P<0.01), but only Pg-LPS showed the similar effect on HGF-1 cells (P<0.01). Neither Pg-LPS nor E-LPS induced KB cells to secrete inflammatory cytokines. CONCLUSION: Pg-LPS can promote target cells to increase their secretion of inflammatory cytokines. KB cells can not be used as the target cell to determine inflammation-causing effect of LPS.

Detection of Helicobacter pylori in dental plaque using a DNA biosensor for noninvasive diagnosis.

Noninvasive diagnosis of Helicobacter pylori (H. pylori) infection is very attractive. This study investigated the single strand DNA (ssDNA) acquisition method from H. pylori in dental plaque, and the integration of our previously developed 43-mer H. pylori DNA biosensor with the obtained target ssDNA (tDNA). Dental plaque samples were collected from 34 patients/volunteers, whose gastric H. pylori infection statuses were tested with the 13C urea breath test (UBT). The samples were treated with colony polymerase chain reaction (PCR) to obtain double strand DNA (dsDNA) of 104 basepairs (bp) long. A blocker ssDNA was designed and used in thermal treatment of the dsDNA to release the 104-mer tDNA, which contains the 43-mer DNA sequence in the middle. PCR primers were designed, and the tDNA releasing and detection conditions with the biosensor were optimized. The limit of detection with the biosensor was 12 fM dsDNA. The dental plaque detection results correlated quite well with the UBT results, with a sensitivity of 100%, and specificity of 97%. These results indicate that the residence of H. pylori in dental plaque is highly associated with gastric H. pylori infection, and detection of dental plaque samples with our DNA biosensor is promisingly applicable in noninvasive diagnosis of H. pylori infection.

Association between infection of different strains of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival plaque and clinical parameters in chronic periodontitis.

OBJECTIVE: The aim of this study was to investigate subgingival infection frequencies of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans strains with genetic variation in Chinese chronic periodontitis (CP) patients and to evaluate its correlation with clinical parameters. METHODS: Two multiplex polymerase chain reaction (PCR) assays were developed to detect the 16SrDNA, collagenase (prtC) and fimbria (fimA) genes of P. gingivalis and the 16SrDNA, leukotoxin (lktA) and fimbria-associated protein (fap) genes of A. actinomycetemcomitans in 60 sulcus samples from 30 periodontal healthy subjects and in 122 subgingival plaque samples from 61 patients with CP. The PCR products were further T-A cloned and sent for nucleotide sequence analysis. RESULTS: The 16SrDNA, prtC and fimA genes of P. gingivalis were detected in 92.6%, 85.2% and 80.3% of the subgingival plaque samples respectively, while the 16SrDNA, lktA and fap genes of A. actinomycetemcomitans were in 84.4%, 75.4% and 50.0% respectively. Nucleotide sequence analysis showed 98.62%~100% homology of the PCR products in these genes with the reported sequences. P. gingivalis strains with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ were predominant in deep pockets (>6 mm) or in sites with attachment loss > or =5 mm than in shallow pockets (3~4 mm) or in sites with attachment loss < or =2 mm (P<0.05). P. gingivalis strains with prtC+/fimA+ also showed higher frequency in gingival index (GI)=3 than in GI=1 group (P<0.05). CONCLUSION: Infection of P. gingivalis with prtC+/fimA+ and A. actinomycetemcomitans with lktA+ correlates with periodontal destruction of CP in Chinese. Nonetheless P. gingivalis fimA, prtC genes and A. actinomycetemcomitans lktA gene are closely associated with periodontal destruction, while A. actinomycetemcomitans fap gene is not.