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There are growing evidences linking chronic apical periodontitis (CAP) to atherosclerosis. Gut microbiota is found to be involved in the development of atherosclerosis. Recent studies have shown that CAP could change the diversity and composition of the gut microbiota. It was therefore, we hypothesized that gut microbiota and its metabolites could mediate the impact of CAP on atherosclerosis.Twenty-four 5-week-old lipoprotein E knockout (apoEAlterations of alpha and beta diversity were shown both in the CAP and the Co-CAP groups. Moreover, the percentage of atherosclerotic lesion area increased in the CAP and Co-CAP groups (p .05). Linear discriminant analysis effect size (LEfSe) at the family level found the increases of Lachnospiraceae and Ruminococcaceae (p .05), which were positively correlated with serum TMAO levels (p .05). In the redundancy analysis technique (RDA), serum levels of TMAO were positively associated with the atherosclerotic lesions. Co-occurrence analysis revealed that the relative abundances of Lachnospiraceae and Porphyromonadacae were positively correlated with both the percentage of lesion area and TMAO level (p .05).Thus, within the limitations of this study, the data suggest that the gut microbiota can mediate the effects of CAP on atherosclerosis.

A new individualized, cost-effective, modified semi-computer-assisted surgery (MSCAS) concept for free fibular flap mandibular reconstruction is reported and compared with the computer-assisted surgery (CAS) concept. Patients were divided into two groups and retrospectively reviewed. In the MSCAS and CAS groups, intraoperative guides were created using computer-aided design with manual fabrication and computer-aided design and manufacturing, respectively. Differences in specific linear and angular parameters on pre- and postoperative computed tomography scans were calculated for morphometric comparison, and clinical parameters and efficiency were analysed. RESULTS: Eighteen patients (CAS, 7; MSCAS, 11), were included. The morphometric comparison showed no significant differences between the groups. The mean deviation of the mandibular ramus length, body length, width 1 and width 2 was 0.82 ± 0.29 mm, 1.84 ± 0.43 mm, 1.89 ± 0.61 mm and 1.45 ± 0.61 mm in the CAS group versus 1.56 ± 0.54 mm, 1.72 ± 0.33 mm, 2.24 ± 0.55 mm and 2.36 ± 0.50 mm in the MSCAS group (p = 0.7804, p = 0.9997, p = 0.9814 and p = 0.6334). The mean deviation of the sagittal, axial and coronal mandibular angles was 1.56 ± 0.48°, 1.93 ± 0.50° and 2.15 ± 0.72° in the CAS group versus 2.19 ± 0.35°, 1.86 ± 0.35° and 1.94 ± 0.55° in the MSCAS group (p = 0.7594, p = 0.9996 and p = 0.9871). There were no significant differences in clinical parameters, efficiency or postoperative complications between the groups. CONCLUSION: The accuracy and operative efficiency of the MSCAS concept are comparable to those of the more expensive CAS concept. Therefore, in times of increasing clinical costs, this concept might be an adequate and inexpensive alternative to preoperative CAS.

Background and objectives This study aimed to evaluate the effect of optimized irrigation with photon-induced photoacoustic streaming (PIPS) activation of different irrigants (distilled water or ethylenediaminetetraacetic acid [EDTA]) on smear layer removal, dentin microhardness, attachment morphology, and survival of stem cells of the apical papilla (SCAP) in an organotypic root canal model. Study design/materials and methods A total of 144 standardized root segments were randomly allocated into 6 groups for irrigation: (i) NaOCl group, (ii) NaOCl + EDTA group, (iii) NaOCl + PIPS (distilled water) group, (iv) NaOCl + PIPS (EDTA) group, (v) NaOCl + EDTA + PIPS (distilled water) group, and (vi) NaOCl + EDTA + PIPS (EDTA) group. Each group was divided into four subgroups for assessment: (i) dentin cleanliness; (ii) dentin microhardness; (iii) cell attachment morphology; and (iv) viable SCAP quantification. Results Compared with the control groups, the NaOCl + EDTA + PIPS (EDTA) group showed higher efficiency in smear layer removal and in increasing SCAP viability with more stretched cellular morphology. There were no statistically significant differences in either smear layer removal effect, dentin microhardness, attachment morphology, or survival of SCAP among the other groups when optimized with PIPS (distilled water or EDTA) (P > 0.05). Conclusions Our findings indicated that irrigation optimized with PIPS activation of EDTA for 40 seconds was conducive to smear layer removal without additional dentin microhardness decrease. Additionally, this irrigation created more cell-friendly dentin conditioning than other approaches, which was beneficial for the attachment and survival of SCAP. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

The pathology of Alzheimer's disease (AD) is featured with extracellular amyloid-β (Aβ) plaques, whose impact on the mechanical properties of the surrounding brain tissues is unclear. Microglia sense and integrate biochemical cues of the microenvironment. However, whether the microglial mechanosensing pathways influence AD pathogenesis is unknown. Here, we surveyed the elevated stiffness of Aβ-plaque-associated tissues and observed the selective upregulation of the mechanosensitive ion channel Piezo1 in Aβ-plaque-associated microglia. Piezo1 sensed the stiffness stimuli of Aβ fibrils and subsequently induced Ca

Growing evidence indicates that the non-coding 3'-untranslated region (3'UTR) of genes acts as competing endogenous RNAs (ceRNAs) to exert their roles in a number of diseases, including cancer. In the present study, MMP1 messenger RNA was identified to be significantly up-regulated in oral squamous cell carcinoma (OSCC) tissues, and both MMP1 and its 3'UTR promoted tumor growth and cell motility. Further mechanism investigations indicated that MMP1 3'UTR was able to antagonize miR-188-5p; in addition, overexpression of MMP1 3'UTR up-regulated the expression level of SOX4 and CDK4, target genes of miR-188-5p, which have also been identified as oncogenic driver genes in OSCC. Therefore, a ceRNA regulatory network among MMP1, SOX4, and CDK4 mediated via competing for binding to miR-188-5p was proved. Taken together, the present study demonstrates for the first time that MMP1 mRNA participates in the development of OSCC via ceRNA regulatory mechanism and genes involved in the ceRNA network may provide a novel avenue for target therapy.

Aim To investigate the impact of chronic apical periodontitis (CAP) on atherosclerosis and gut microbiota by establishing a Porphyromonas gingivalis (P. gingivalis) induced CAP in a apolipoprotein E-deficient (apoE-/- ) mice model. Methodology Twenty-eight male apoE-/- mice were divided into two groups with 14 in each: CAP group and control group. In the CAP group, sterile cotton wool containing 108 colony-forming units (CFU) of P. gingivalis was placed into the pulp chamber after pulp exposure followed by coronal resin filling in bilateral maxillary first and second molars. The mice were fed with a chow diet to induce atherosclerosis. Animals were euthanized 16 weeks after the operation, and the periapical lesions (PALs) of bilateral maxillary first and second molars were assessed by micro-CT. After collection of aortic arches, atherosclerotic lesions were measured by Oil Red O staining. Serum levels of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglycerides (TG) were measured. Stools were collected to detect alterations in gut microbiota by 16S rRNA gene sequencing. Independent samples t-test was used to calculate the difference between the two groups. Results CAP was observed in 98.2% of molars. A significant increase in atherosclerotic plaque formation in the aortic arches was found in the CAP groups (CAP: 2.001%±0.27%, control: 0.927%±0.22%, P=0.005). The serum level of HDL-C was decreased (CAP: 2.295±0.31 mmol/L, Control: 3.037±0.55 mmol/L, P=0.264) in the CAP group, and the level of LDL-C was increased (CAP: 17.066±3.95 mmol/L, Control: 10.948±1.69 mmol/L, P=0.177) but without significant difference (P>0.05). There were no significant differences in TG (CAP: 1.076±0.08mmol/L, control: 1.034±0.13 mmol/L, P=0.794) or TC (CAP: 6.372±0.98mmol/L, control: 6.679±0.75 mmol/L, P=0.72) levels between the two groups (P>0.05). The alpha diversity was elevated in the CAP group. In terms of beta diversity, the CAP and control groups were clearly distinguished by the microbial community. Conclusion In a mouse experimental model, pulp infection with P. gingivalis induced CAP, thus aggravating the development of atherosclerosis. Meanwhile, CAP increased alpha diversity and altered the beta diversity of the gut microbiota.

We report a polarization-independent unnaturally high refractive index metamaterial. It is found that the effective permittivity of the designed metamaterial can be drastically increased by the capacitive coupling effect. Also, the effective permeability of metamaterial can be increased by reducing the diamagnetic effect by designing a thin structure. In our work, the single-layer multi-band high refractive index metamaterials with a peak achieving to 26.8 at 0.9 THz is demonstrated. Furthermore, the three-dimensional metamaterial possessing high refractive index more than 85 around 0.91 THz can be constructed by a double-layer tricyclic structure. Ultrabroadband and ultrahigh refractive index of designed metamaterials can be obtained by multilayer coupling effect. In addition, the polarization-independent property and wide-angle performance of high refractive index metamaterial are exhibited.

Various antimicrobial modalities have been proposed to treat peri-implantitis but resulted in limited outcomes. The aim of this in vitro study was to evaluate the disinfection efficacy of combined application of chlorhexidine digluconate (CHX) and antimicrobial photodynamic therapy (aPDT) of titanium surfaces previously contaminated with Porphyromonas gingivalis biofilm. P. gingivalis biofilms were grown on 32 polished and 32 sandblasted large-grit acid-etched (SLA) titanium surfaces. Titanium disks were allocated into four groups as follows: (1) immersed in phosphate-buffered saline (PBS), (2) immersed in 0.2% CHX, (3) application of aPDT and (4) immersed in 0.2% CHX and subsequent aPDT. Residual bacteria were determined by microbial culture analysis and by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) imaging. Combination protocol (CHX+ aPDT) was the most effective in eradicating P. gingivalis (P 0.05) on both polished and SLA surfaces. There was no significant difference in the number of remaining P. gingivalis between polished titanium disks and the SLA ones in four groups (P 0.05). Under the limitation of this study, combined technique of preceding application of CHX and subsequent aPDT was shown to be an efficient method in reducing P. gingivalis numbers in both polished and SLA titanium surfaces.

BACKGROUND The D-alanylation of lipoteichoic acid (LTA) is essential for the physiological metabolism of Streptococcus mutans (S. mutans). This study was designed to investigate the influence of D-alanylation of LTA on interspecies competitiveness of S. mutans. METHODS The process of D-alanylation was blocked by the inactivation of dltC. Agar competition assays, conditioned medium assays, and qRT-PCR were used to evaluate the production of antimicrobial compounds in S. mutans mutant. Dual-species biofilm was formed to investigate the competitiveness of S. mutans mutant cocultured with S. sanguinis or S. gordonii. RESULTS S. mutans mutant could not produce antimicrobial compounds efficiently when cocultured with commensal bacteria (*p

Candida albicans (C.albicans) is the primary pathogen of denture biofilm. Moreover, it could establish a cross-kingdom relationship with bacteria to enhance its virulence and resistance to antifungal drugs. This study aimed to investigate the efficacy of antimicrobial photodynamic therapy (aPDT) in combination with hydrogen peroxide (HC.albicans and S.mutans were grown on PMMA disk for 48 h to form biofilm and received different treatments. The treatments included:1) phosphate-buffered saline (PBS) group,2) 100 mM HThere was no significant difference between PBS group and HPretreatment with H

A novel Symplectic Analytical Singular Element (SASE), defined by the analytical symplectic eigen expanding terms, is used within the framework of the finite element method (FEM), to obtain the dynamic stress intensity factors (DSIFs) of bi-material interface cracks under dynamic loading. In the space domain, the vicinity of the crack tip is represented by using the SASE, while the other area is meshed with conventional elements. In the time domain, the precise time domain expanding algorithm is adopted, in which a self-adaptive technique is carried out to improve computing accuracy. Taking advantage of the SASE, DSIFs can be obtained directly without any post-processing through the relationship between the DSIFs and the eigen expanding coefficients. The numerical accuracy and stability of the proposed method are investigated carefully through the conducted numerical examples. The results show that the present method is effective and efficient.

Background Blood Clot (BC) or platelet concentrates have been used as scaffold in regenerative endodontic treatment (RET). The aim of this retrospective study was to compare the performance of platelet-rich fibrin (PRF) with BC in inducing root development and periapical lesion healing after tooth revascularization. Methods Five patients receiving RET using PRF as a scaffold were matched 1:1 to a previous cohort of 5 patients who underwent tooth revascularization by provoking periapical bleeding. Clinical signs and symptoms were examined at follow-ups. Periapical lesion healing and root development were monitored radiographically. The resolution of clinical signs and symptoms as well as periapical radiolucency was observed in all patients (100%). Results Root elongation, dentinal wall thickening and apex closure were found in most cases (80% in both groups). There was no significant difference between the groups in terms of clinical sign resolution, root development and periapical healing. Conclusions Within the limits of this study, PRF achieved comparable outcomes to BC in terms of clinical sign and symptom resolution, periapical lesion healing and continued root development in RET.

In this paper, the two-dimensional (2D) crack problem under dynamic loading condition is studied. Firstly, by the precise time domain expanding algorithm, the recursive formulation of the governing equation is derived, and the recursive equation can be solved by FEM. Then, a new Symplectic Analytical Singular Element (SASE) defined by the analytical symplectic eigen expanding terms is further developed for the investigated problem. The area near the crack tip is represented by using the SASE, while the other area is meshed by conventional elements. Taking advantage of the SASE, the crack problem can be solved with higher accuracy. Simultaneously, the dynamic stress intensity factors (DSIFs) can be obtained directly without any post processing through the relationship between the DSIFs and the eigen expanding coefficients. The numerical accuracy and stability is investigated carefully through the conducted numerical examples. It has been demonstrated that the proposed SASE for dynamic crack problem is effective and efficient.

No in vivo study has been reported on the mechanical reinforcement of a tooth after regenerative endodontic treatment (RET). The present work aimed to evaluate the concurrent use of platelet-rich fibrin (PRF) with a blood clot (BC) in RET concerning periapical healing, root development, and tooth structural reinforcement.In our study, 24 premolars from 3 beagle dogs were assigned into control, BC, and PRF + BC groups. Periapical healing was monitored with quantitative measurements of root elongation and thickening radiographically. Tooth biomechanical integrity was assessed with the fracture resistance test. Histologic evaluation was conducted.There was a significant difference among the periapical radiolucency decreasing rate of the control (43.75%) and the BC (100%) and PRF + BC (100%) groups (P .05). The increase of root length and thickness in both the BC and PRF + BC groups was significantly greater than that in the control group (P .05). No significant difference was detected between the 2 experimental groups regarding periapical healing or root development (P .05). Teeth in the BC (249.3 ± 64.1 N) and PRF + BC (281.7 ± 37.8 N) groups had significantly higher fracture resistance than those in the control group (108.5 ± 23.3 N) (P .05). No significant difference was revealed between the BC and PRF + BC groups (P .05). Histologic evidence of cementumlike tissue deposition along the canal wall with scattered bonelike tissue in the canal was observed.Either a combination of PRF with BC or BC alone could improve periapical healing, induce root development, and reinforce tooth structure. No additional benefit of PRF to BC in RET was found.

This study was to test the hypothesis that root canal pretreated with photodynamic therapy (PDT) would promote stem cells from the apical papilla (SCAP) adhesion, proliferation and differentiation without affecting smear layer removal and microhardness of root canal. Standardized root canals were randomized into four groups (n = 30/group): (1) sodium hypochlorite(NaOCl) group, (2) NaOCl + ethylene diaminetetraacetic acid (EDTA) group, (3) NaOCl + PDT group, (4) NaOCl + EDTA + PDT group. After treatments, smear layer removal and microhardness of root canal were evaluated. SCAP with hydroxyapatite-based scaffolds were seeded into root canals for 7 days. SCAP adhesion was observed by scanning electron microscope (SEM), and viable cells were calculated by CellTiter-Glo Luminescent kit. Platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) expression of SCAP were evaluated by Quantitative Reverse Transcriptase-Polymerase Chain Reaction. There was no significant difference in the smear layer removal and microhardness of root dentin between the groups with and without PDT treatment (P > 0.05). SCAP with elongated cytoplasmic processes and cell-cell contact were observed on the dentin surfaces treated with PDT. Elevated cell viability, PDGF and VEGF expression were found in root canal treated with PDT (P < 0.05). Under the experimental conditions, PDT could provide positive microenvironment for SCAP growth.

Antimicrobial photodynamic therapy (aPDT) has been recommended for clinical application. Its antibacterial effect on bacteria remained in dentinal tubule was seldom investigated. Here, we evaluated the antibacterial effects of aPDT on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) in planktonic lifestyle, biofilm and carious dentine. Mono-species biofilms or dentinal caries formed on human dentine slices or slabs. Bacterial suspension, biofilms and dentine caries were treated with 0.1 mg mL-1 toluidine Blue O followed by irradiation with a light emission diode (λ - 635 ± 10 nm; 500 mW; 31.5 J cm-2 ; 60 s) and 0.12% chlorhexidine (CHX), respectively. Residual bacteria were determined by microbial culture analysis and scanning electron microscopy (SEM). One-way analysis of variance (ANOVA) was performed to detect the significance of the variables. Both treatments significantly reduced the number of L. acidophilus in planktonic state, biofilm and carious dentine (P 0.05). Under the experimental conditions assessed, aPDT could be an alternative disinfection method for superficial layer of caries cavity. Its disinfection on bacteria in dentinal tubule of deep layer was deficient.

Background Extracorporeal shock wave therapy (ESWT) can modulate cell behavior through mechanical information transduction. Human periodontal ligament fibroblasts (hPDLF) are sensible to mechanical stimulus and can express pro-inflammatory molecules in response. The aim of this study was to evaluate the impacts of shock waves on interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemotactic protein 1 (MCP-1), and tumor necrosis factor-alpha (TNF-α) expression by hPDLF. Material/Methods After being treated by shock waves with different parameters (100–500 times, 0.05–0.19 mJ/mm2), cell viability was tested using CCK-8. IL-6, IL-8, MCP-1, and TNF-α gene expression was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and IL-6 and IL-8 protein was measured by enzyme-linked immunosorbent assay (ELISA) at different time points. Results Shock waves with the parameters used in this study had no significant effects on the viability of hPDLF. A statistical inhibition of IL-6, IL-8, MCP-1, and TNF-α expression during the first few hours was observed (P

Objectives The aim of this study was to test the following hypothesis: (1) Aging would adversely affect bone integration of implants; (2) Titanium-zirconium-SLActive (TiZr-SLActive) implant might perform better in osseointegration than Ti-SLA implant in aged group. Materials and Methods Thirteen miniature pigs (six of them were young adult minipigs, with other seven being aged ones.) were enrolled in this study. The right mandibular premolars (P1, P2, P3) and the first molar (M1) were extracted in all animals. Three months later, one TiZr-SLActive and one Ti-SLA implants were inserted into the endentulous area in mandible of each animal. The animals were sacrificed 8 weeks after placement of implants. Implants in the mandibles were used for removal torque (RT) tests, while vertebra and femur being retrieved for bone mineral density (BMD) tests. Results Implant success rate in the young group was significantly higher than that in the aged group. Higher survival rate of implants was also observed in younger group than that in the aged group but without significant difference. Within the young group, mean value for peak RT of Ti-SLA implants was higher than that of TiZr-SLActive implants without significant difference. In the aged group, the TiZr-SLActive implants showed a higher mean value for peak RT than Ti-SLA implants. No significant difference was found in the mean BMD in both vertebra and femur between different age groups. Conclusions Within the limits of this study, aging could negatively affect osseointegration of dental implants. TiZr-SLActive implants might to some degree compensate for the compromise in osseointegration brought by aging.

Background S. aureus biofilm plays a predominant role in the establishment and development of peri-implantitis. It is suggested to combine different modalities as peri-implantitis treatment. The aim of this study was to evaluate the disinfection efficacy of combined application of antiseptics with PDT on Staphylococcus aureus (S. aureus) biofilm formed on titanium(Ti) disks with different surface roughness. Methods S. aureus biofilm was incubated on polished and sandblasted large-grit acid-etched (SLA) Ti surfaces for 48 h. 72 contaminated Ti disks (36 polished, 36 SLA) were randomly divided into 6 different groups as follows: (a) PBS, (b) 0.2% chlorhexidine digluconate (CHX), (c) 3% hydrogen peroxide (H2O2), (d) PDT, (e) 0.2% CHX + PDT, and (f) 3% H2O2+PDT. Colony forming unit (CFU) was measured to determine antimicrobial effects. Biofilm structure was assessed using scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM). Results All disinfection methods significantly reduced bacteria amounts compared to control group on both polished and SLA Ti surfaces (P Conclusion The combination of CHX or H2O2 administration with PDT was more effective in eradicating S. aureus on both polished and SLA Ti disks in comparison with either treatment alone, suggesting that combined usage of antiseptics with PDT could be a more efficient method for the treatment of peri-implantitis.

Purpose This study aimed to investigate the feasibility of adopting the ThormalGEN surgical patch (a porcine decellularized pericardial patch) in the superficial parotidectomy to prevent postoperative Frey's syndrome in patients with benign parotid tumor. Materials and methods A total of 59 patients with benign parotid tumor undergoing superficial parotidectomy between April 2016 and January 2017 were enrolled, and divided into the ThormalGEN group (n = 37) and the control group (n = 22) based on their willingness to have the ThormalGEN surgical patch used in the superficial parotidectomy. At 6 months postoperation, the incidences of postoperative complications and Frey's syndrome were assessed by subjective assessment (patient self-assessment) and objective assessment (starch-iodine test), respectively. The risk factor of Frey's syndrome was analyzed by the multivariate logistic regression model. Results The starch-iodine test, for objective assessment, showed that the ThormalGEN group had a significantly lower incidence of Frey's syndrome than the control group (8.11% vs. 40.91%, p = 006). However, in the patient self-assessment, there was no significant difference in the incidence of Frey's syndrome between groups (8.11% [3/37] vs. 13.64% [3/22], p = 0.4968). The incidences of postoperative complications were not significantly different between group (all p > 0.05). Two patients (5.41%) in the ThormalGEN group had salivary fistula. Multivariate logistic regression analysis showed that the ThormalGEN group had a significantly lower risk of Frey's syndrome than the control group (odds ratio = 0.11, 95% confidence interval = 0.02–0.51, p Conclusion These results suggest that the ThormalGEN surgical patch can effectively reduce the incidence of Frey's syndrome following superficial parotidectomy in patients with benign parotid tumor, and that this patch has a good safety and biocompatibility profile.

To conduct three-dimensional micro-CT analysis of bone destruction, periapical sclerotic changes and inflammatory root resorption (IRR) to compare the differences between Enterococcus faecalis (Ef)- and Porphyromonas gingivalis (Pg)-induced chronic apical periodontitis (CAP).Mono-species bacteria-induced CAP was established in the first and second molars of the right maxilla and mandible of male Sprague-Dawley rats. Fifteen animals were divided into three groups with five rats in each group: control group, Ef-CAP group and Pg-CAP group. The maxilla and mandible were harvested and then scanned by micro-CT. Alveolar bone destruction was evaluated by measuring the volume of alveolar bone resorption, bone volume fraction (BV/TV), trabecular thickness (Tb. Th), trabecular number (Tb. N) and trabecular spacing (Tb. Sp). The results were analysed using one-way analysis of variance and Fisher's least significant difference methods (LSD). The sclerotic changes in the periapical bone were graded and the IRR indexes were scored. The data were analysed using the chi-square test.The alveolar bone resorption volume of the Pg-CAP group was significantly larger than that of the Ef-CAP group (P 0.01). In the maxilla, both Pg-CAP and Ef-CAP groups had a significant decrease in BV/TV and increase in Tb. Sp (P 0.01) with the more significant changes of trabecular bone in the Pg-CAP group. A significant reduction of Tb. N was only found in the Pg-CAP group (P 0.05). There was no significant change in Tb. Th in either group (P 0.05). In the mandible, except for an increase in Tb. Sp in the Pg-CAP group (P 0.05), there was no significant change in BV/TV, Tb. Th or Tb. N (P 0.05). No obvious sclerotic change was observed. IRR was detected in significantly more root surfaces in the Pg-CAP group (240 surfaces, 60%) than those in the Ef-CAP group (178 surfaces, 44.5%) (P 0.001). The IRR extension was also significantly more advanced in the Pg-CAP group (P 0.05).Pg-CAP caused more substantial alveolar bone destruction and IRR than Ef-CAP. The maxilla was more susceptible to CAP in terms of microstructural changes of trabecular bone than the mandible. Tb. Sp was the most sensitive index for evaluating the residual alveolar bone of CAP.

V-notch problem under dynamic loading condition is considered in this paper. In the time domain, the precise time domain expanding algorithm is employed, in which a self-adaptive technique is carried out to improve computing accuracy. By expanding variables in each time interval, the recursive finite element formulas are derived. In the space domain, a Symplectic Analytical Singular Element (SASE) for V-notch problem is constructed addressing the stress singularity of the notch tip. Combining with the conventional finite elements, the proposed SASE can be used to solve the dynamic stress intensity factors (DSIFs) in a simple way. Numerical results show that the proposed SASE for V-notch problem subjected to dynamic loading condition is effective and efficient., {"references":["Niu Z, Cheng C, Ye J, Recho N, \"A new boundary element approach of modeling singular stress fields of plane V-notch problems,\" Int. J. Solids Struct., vol. 46, no.16, pp. 2999–3008, Aug. 2009.","Ju SH, \"Finite element calculation of stress intensity factors for interface notches,\" Comput. Methods Appl. Mech. Eng., vol. 199, no. 33-36, pp. 2273–2280, Jul. 2010.","Treifi M, Oyadiji SO, Tsang DKL, \"Computation of the stress intensity factors of sharp notched plates by the fractal-like finite element method,\" Int. J. Numer. Meth. Eng., vol. 77, no. 4, pp. 558–580, Jan. 2009.","Noda NA, Takase Y, \"Generalized stress intensity factors of V-shaped notch in a round bar under torsion, tension, and bending,\" Eng. Fract. Mech., vol. 70, no. 11, pp. 1447–1466, Jul. 2003.","Gross B, Mendelson A, \"Plane elastostatic analysis of V-notched plates,\" Int. J. Fract., vol. 8, no. 3, pp. 267–276, Sept. 1972.","Yi G, Yu T, Bui TQ, Ma C, Hirose S, \"SIFs evaluation of sharp V-notched fracture by XFEM and strain energy approach,\" Theor. Appl. Fract. Mec., vol. 89, pp. 35-44, Jun. 2017.","Yao WA, Hu XF, \"A singular finite element on the mixed-mode bimaterial interfacial cracks,\" Int. J. Comput. Meth. Eng. Sci. Mech., vol. 13, no. 4, pp. 219-226, 2012.","Hu XF, Yao WA, \"A new enriched finite element for fatigue crack growth,\" Int. J. Fatigue, vol. 48, pp. 247-256, Mar. 2013.","Yang HT, \"A precise algorithm in the time domain to solve the problem of heat transfer,\" Numer. Heat Tr. B-Fund., vol. 35, no. 2, pp. 243-249, 1999.\n[10]\tYao WA, Zhong WX, Lim CW, Symplectic Elasticity, World Scientific, 2009."]}

The aim of this study was to investigate whether apical periodontitis (AP) could cause systemic cytokine elevation and pathological changes in remote organs in an experimental animal model. AP was induced in 36 Sprague Dawley (SD) rats. Serum levels of C-reactive protein (CRP), interleukin 2 (IL-2), and interleukin 6 (IL-6) were measured by enzyme-linked immunosorbent assays at different time intervals (0, 6, 12, 24, 48, and 96 h and 1, 2, 3, 4, 5, and 6 weeks) after pulp exposure. Multiple organs (the aortic arch, myocardium, liver, and spleen) were collected for histological observation. The results were analyzed by one-way analysis of variance (ANOVA). Serum levels of CRP, IL-2, and IL-6 were significantly elevated at all time points assessed after 6, 24, and 96 h, respectively. The peak values of serum cytokines (CRP 6.363 ± 0.05 ng/ml, IL-2 21.997 ± 0.15 ng/L, and IL-6 2.406 ± 0.02 ng/L) were reached at 1, 4, and 2 weeks, respectively, followed by a decline. Time-dependent reversible histopathological changes were detected in the aortic arch, myocardium, and spleen, whereas irreversible changes were found in the liver. AP elevated the levels of CRP, IL-2, and IL-6 in rat blood serum, causing reversible changes in the aortic arch, myocardium, and spleen as well as irreversible changes in the liver. AP may trigger a systemic immune response, impair remote organs, and affect the general health of patients.

Cytolytic Enterococcus faecalis possesses a highly toxic and proinflammatory capacity. Cytokines and proteases play important roles in the host inflammatory response. The aim of this study was to compare the local expression of interleukin (IL)-1β and matrix metalloproteinase-8 (MMP-8) between persistent apical periodontitis (AP) infected by cytolytic and noncytolytic E. faecalis.Eighty-four left upper first rat molars were divided into 4 groups: chronic AP group (n = 6), disinfection group (n = 6), cytolytic E. faecalis-infected persistent AP group (n = 36), and noncytolytic E. faecalis-infected persistent AP group (n = 36). Periradicular lesions were established after pulp exposure. After 3 weeks, root canals were prepared, and disinfected. E. faecalis strains ATCC 29212 or ATCC 700802 suspensions were inoculated into root canals 2 weeks later. Six samples were collected at different time points (1, 2, 3, 4, 5, and 6 weeks). The expression levels of IL-1β and MMP-8 were detected by immunohistochemical staining.IL-1β and MMP-8 expression trends in the cytolytic groups were similar to those of the noncytolytic group although at different time points the expression levels in the cytolytic group were significantly higher than those in the noncytolytic group (P.01). IL-1β expression enhancement occurred during the early phase of infection, whereas increased MMP-8 expression lasted for a prolonged period.Both E. faecalis strains could induce local IL-1β and MMP-8 expression in persistent AP. Compared with noncytolytic E. faecalis, cytolytic E. faecalis may cause more severe local inflammation and tissue destruction in persistent AP.

Specimens of human immature permanent teeth after regenerative endodontic treatment (RET) are sparse. This case report describes the histologic and immunohistochemical findings of tissue formed in the canal space of a human immature permanent tooth with apical periodontitis after RET. A patient presenting with immature human permanent tooth #29 with apical periodontitis underwent RET. At the 10-month follow-up visit, radiographic examination revealed complete resolution of the periapical lesion, marked narrowing of the apical foramen, increased thickness of the canal walls, and minimal lengthening of the root. Notably, the tooth regained pulp sensibility. Tooth #29 was extracted for orthodontic reasons and processed for histologic and immunohistochemical examination. The canal space was filled with newly formed cementumlike tissue, bonelike tissue, and fibrous connective tissue. The apical closure, thickness, and length increment of the root were caused by the deposition of cementumlike tissue without dentin. Furthermore, neurons and nerve fibers were observed in the canal space; this observation was confirmed by immunohistochemistry. Based on the findings in the present case, after RET, the newly formed tissues in the canal space of the human immature permanent tooth with apical periodontitis were primarily fibrous connective tissue, cementumlike tissue, and bonelike tissue. Nerve regeneration was identified.

Background/purpose Biofilm formation by Streptococcus mutans is a prerequisite for the development of caries. Different strains of S. mutans may differ in their capacity in biofilm formation and protein expression. The objective of this study was to investigate the morphological features and proteomes of biofilms of S. mutans clinical isolates. Materials and methods Clinical strains isolated from caries-active (SM 593) and caries-free (SM 18) adults were cultured on polystyrene sheets in tryptone–polypeptone–yeast extract medium. Biofilm formation and structure were assessed by confocal laser scanning microscopy and scanning electron microscopy. Proteins were extracted from SM 593 and SM 18 presented in biofilms and separated with two-dimensional gel electrophoresis, followed by peptide mass fingerprinting using matrix-assisted laser desorption time-of-flight mass spectrometry analysis. Results Initially detected 2 hours after incubation, biofilm formation reached its maximum level at 20 hours. The biofilm formed by SM 593 was thicker with a higher percentage of viable bacteria compared with that formed by SM 18. Hydrolase and pantothenate kinase were detected in the SM 593 biofilm only, whereas 6-pyruvoyl tetrahydropterin synthase and phosphoribosylglycinamide formyltransferase were expressed exclusively in the SM 18 biofilm. Expressions of D-alanyl-D-alanine carboxypeptidase and response regulator homolog of RumR were most greatly enhanced in the SM 593 and SM 18 biofilms, respectively. Conclusion SM 593 exhibited greater biofilm-forming capacity compared to SM 18. SM 593 and SM 18 biofilms expressed specific proteins involved in nucleic acid metabolism and intermediary metabolism, respectively, which may account for the differences in their biofilm-forming abilities.

Objective The objective of this study was to compare soft tissue healing after implant placement in flap and flapless surgery in the dog model. Study Design Mandibular premolars were extracted from 10 beagle dogs. The extraction sockets were allowed to heal for 8 weeks. After healing, 3 implants on each side of the mandible were implanted using either flap or flapless techniques. One implant was installed on each side at the 0-, 4-, and 6-week time point. Eight weeks later, the peri-implant soft tissue healing was subjected to clinical and immunohistochemical analysis. Results It was revealed that vascular endothelial growth factor (VEGF) expression, peri-implant crevicular fluid (PICF) volume, and the aspartate aminotransferase and alkaline phosphatase activity in PICF increased significantly in the 2-week flap group compared with the 2-week flapless group. Microvascular density and VEGF expression in the 8-week flap group was statistically significantly lower than the 8-week flapless group and normal group. Buccal gingival recession was less pronounced in the flapless group than in the flap group after 4 and 8 weeks. Conclusions Within the limits of this study, the results demonstrate that flapless surgery contributes to better esthetic outcomes in implants compared with the flap approach.