Antibacterial activity of viable and heat-killed probiotic strains against oral pathogens.

Probiotics can stabilize gut flora, regulate intestinal immunity and protect the host from enteric diseases; however, their roles in oral health have received little attention compared to their roles in gut health. Nowadays, the prevalence of sugar-sweetened foods and abuse of antibiotics contribute towards dysbiosis of oral microbiota and drug resistance development in oral pathogens, resulting in various intractable oral diseases. We screened the antibacterial activities of viable and heat-killed probiotic strains against the oral pathogens Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans. The probiotic strains Lactobacillus salivarius subsp. salicinius AP-32, L. rhamnosus CT-53, L. paracasei ET-66 and Bifidobacterium animalis subsp. lactis CP-9 displayed strong antipathogenic activities, whereas heat-killed AP-32, CT-53 and ET-66 displayed high levels of pathogen inhibition. The antibacterial activities of these probiotics were not associated with their H2 O2 production; L. acidophilus TYCA02 produced high levels of H2 O2 but merely exhibited moderate antibacterial activities. Oral tablets containing probiotics showed positive inhibitory effects against oral pathogens, particularly those containing viable probiotics. Our results indicate that probiotics prevent the growth of oral pathogens and improve oral health, providing insights into the antipathogenic efficacy of different probiotic species and their potential role in functional foods that improve oral health. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study provides insights into the antipathogenic efficacy of different probiotic species and their potential roles in developing functional foods to improve oral health. We showed that the probiotic strains Lactobacillus salivarius subsp. salicinius AP-32, L. rhamnosus CT-53, L. paracasei ET-66 and Bifidobacterium animalis subsp. lactis CP-9 have great potential for use in the development of functional foods to improve oral health. Since active probiotics may provide strong and long-term protection, the development of functional food products should favour the use of viable bacteria.

Functionalization of endovascular devices with superparamagnetic iron oxide nanoparticles for interventional cardiovascular magnetic resonance imaging.

Presently, cardiovascular interventions such as stent deployment and balloon angioplasty are performed under x-ray guidance. However, x-ray fluoroscopy has poor soft tissue contrast and is limited by imaging in a single plane, resulting in imprecise navigation of endovascular instruments. Moreover, x-ray fluoroscopy exposes patients to ionizing radiation and iodinated contrast agents. Magnetic resonance imaging (MRI) is a safe and enabling modality for cardiovascular interventions. Interventional cardiovascular MR (iCMR) is a promising approach that is in stark contrast with x-ray fluoroscopy, offering high-resolution anatomic and physiologic information and imaging in multiple planes for enhanced navigational accuracy of catheter-based devices, all in an environment free of radiation and its deleterious effects. While iCMR has immense potential, its translation into the clinical arena is hindered by the limited availability of MRI-visible catheters, wire guides, angioplasty balloons, and stents. Herein, we aimed to create application-specific, devices suitable for iCMR, and demonstrate the potential of iCMR by performing cardiovascular catheterization procedures using these devices. Tools, including catheters, wire guides, stents, and angioplasty balloons, for endovascular interventions were functionalized with a polymer coating consisting of poly(lactide-co-glycolide) (PLGA) and superparamagnetic iron oxide (SPIO) nanoparticles, followed by endovascular deployment in the pig. Findings from this study highlight the ability to image and properly navigate SPIO-functionalized devices, enabling interventions such as successful stent deployment under MRI guidance. This study demonstrates proof-of-concept for rapid prototyping of iCMR-specific endovascular interventional devices that can take advantage of the capabilities of iCMR.

Photoinduced antibacterial activity of NRC03 peptide-conjugated dopamine/nano-reduced graphene oxide against Staphylococcus aureus.

In recent years, several drugs have become relatively easy to obtain with the rapid development of the economy and improvement in people's living standards. However, pathogenic bacteria have evolved strains that are resistant to certain drugs, such as antibiotics. Peptides are generally considered to be safe, have high tolerance to drugs, and are easy to manufacture. However, peptides are easily decomposed in complex biological environments. To solve this problem, many studies have modified peptides on the surface of nanomaterials to increase their functionality, biocompatibility, and stability. Meanwhile, nanomaterials have exhibited good absorption of near-infrared (NIR) light. When the NIR laser is focused on nanomaterials, photons are absorbed and the energy of the photons is converted into heat. Low-toxicity NRC03 peptide-conjugated dopamine/nano-reduced-graphene oxide (NRC03-DA/nRGO) nanomaterials are synthesized in this study for antibacterial testing using photothermal technology. The strains used in this study were Gram-positive Staphylococcus aureus (S. aureus). Our results indicated that the synthesized NRC03-DA/nRGO exhibits good absorption of NIR light and high photothermal conversion efficiency. Moreover, the synthesized NRC03-DA/nRGO inhibits the growth and survival of S. aureus. When the NRC03 peptide is modified on the surface of DA/nRGO, its biological stability is improved and the photothermal effect generated by NIR light produces additive effects, thereby indicating potential antibacterial applications.

Use of 0.4-Tesla static magnetic field to promote reparative dentine formation of dental pulp stem cells through activation of p38 MAPK signalling pathway.

AIM: To investigate whether static magnetic fields (SMFs) have a positive effect on the migration and dentinogenesis of dental pulp stem cells (DPSCs) to promote reparative dentine formation. METHODOLOGY: In vitro scratch assays and a traumatic pulp exposure model were performed to evaluate the effect of 0.4-Tesla (T) SMF on DPSC migration. The cytoskeletons of the DPSCs were identified by fluorescence immunostaining and compared with those of a sham-exposed group. Dentinogenic evaluation was performed by analysing the expressions of DMP-1 and DSPP marker genes using a quantitative real-time polymerase chain reaction (qRT-PCR) process. Furthermore, the formation of calcified deposits was examined by staining the dentinogenic DPSCs with Alizarin Red S dye. Finally, the role played by the p38 MAPK signalling pathway in the migration and dentinogenesis of DPSCs under 0.4-T SMF was investigated by incorporating p38 inhibitor (SB203580) into the in vitro DPSC experiments. The Student's t-test and the Kruskal-Wallis test followed by Dunn's post hoc test with a significance level of P < 0.05 were used for statistical analysis. RESULTS: The scratch assay results revealed that the application of 0.4-T SMF enhanced DPSCs migration towards the scratch wound (P < 0.05). The cytoskeletons of the SMF-treated DPSCs were found to be aligned perpendicular to the scratch wound. After 20 days of culture, the SMF-treated group had a greater number of out-grown cells than the sham-exposed group (nonmagnetized control). For the SMF-treated group, the DMP-1 (P < 0.05) and DSPP genes (P < 0.05), analysed by qRT-PCR, exhibited a higher expression. The distribution of calcified nodules was also found to be denser in the SMF-treated group when stained with Alizarin Red S dye (P < 0.05). Given the incorporation of p38 inhibitor SB203580 into the DPSCs, cell migration and dentinogenesis were suppressed. No difference was found between the SMF-treated and sham-exposed cells (P > 0.05). CONCLUSION: 0.4-T SMF enhanced DPSC migration and dentinogenesis through the activation of the p38 MAPK-related pathway.

[Influence of thread shapes of custommade root-analogue implants on stress distribution of peri-implant bone: A three-dimensional finite element analysis].

OBJECTIVE: To explore the effects from the thread shapes of custom-made root-analogue implant (RAI) on distributions of von Mises stress around the peri-implant bone. METHODS: Five one-stage RAI three-dimensional finite element (FE) models with different thread shapes (V-shaped design, square design, buttress design, reverse buttress design and none thread design) and congruent bone were created through reverse engineering technology. The data of the five models were imported into the FE analysis software to calculate. A force of 100 N was applied parallelly and of 45° to the implant axis respectively. Analysis was performed to evaluate the von Mises stress distributions at the peri-implant regions with the help of the Ansys 16 software. RESULTS: The von Mises stresses distributed mostly at the implant cervical regions and the tip ends of the threads on the cortical bone under oblique loading, while on the cancellous bone, the stresses concentrated mostly on the implant lateral cervical regions, the tip ends of the threads and the apical regions. When under vertical loading, the von Mises stresses distributed mostly at the implant cervical regions on the cortical bone while at the tip ends of the threads and the lateral apical regions on the cancellous bone. The von Mises stresses were better distributed on the thread groups under both kinds of loadings compared with no thread design. But there was no obvious difference among the different thread groups. The concentrations of the von Mises stresses on the cancellous bone in the thread groups were mostly at the tip ends of the threads while less in the apical area. The von Mises stresses were better distributed on the cancellous bone on the other three thread designs than on square design. CONCLUSION: Thread designs are advocated for the reason that adding thread designs to the RAI standard design will have a positive effect on stress distributions at the peri-implant regions and it will reduce the concentrations of von Mises stresses on the cortical bone. From the standpoint of the stress distribution, V-shaped design, buttress design and reverse buttress design are more suitable for RAI than square design. There is no difference of the distributions of the von Mises stresses in the RAI between different thread designs.

Phase III randomized study of second line ADI-PEG 20 plus best supportive care versus placebo plus best supportive care in patients with advanced hepatocellular carcinoma.

Background: Arginine depletion is a putative target in hepatocellular carcinoma (HCC). HCC often lacks argininosuccinate synthetase, a citrulline to arginine-repleting enzyme. ADI-PEG 20 is a cloned arginine degrading enzyme-arginine deiminase-conjugated with polyethylene glycol. The goal of this study was to evaluate this agent as a potential novel therapeutic for HCC after first line systemic therapy. Methods and patients: Patients with histologically proven advanced HCC and Child-Pugh up to B7 with prior systemic therapy, were randomized 2 : 1 to ADI-PEG 20 18 mg/m2 versus placebo intramuscular injection weekly. The primary end point was overall survival (OS), with 93% power to detect a 4-5.6 months increase in median OS (one-sided α = 0.025). Secondary end points included progression-free survival, safety, and arginine correlatives. Results: A total of 635 patients were enrolled: median age 61, 82% male, 60% Asian, 52% hepatitis B, 26% hepatitis C, 76% stage IV, 91% Child-Pugh A, 70% progressed on sorafenib and 16% were intolerant. Median OS was 7.8 months for ADI-PEG 20 versus 7.4 for placebo (P = 0.88, HR = 1.02) and median progression-free survival 2.6 months versus 2.6 (P = 0.07, HR = 1.17). Grade 3 fatigue and decreased appetite occurred in <5% of patients. Two patients on ADI-PEG 20 had ≥grade 3 anaphylactic reaction. Death rate within 30 days of end of treatment was 15.2% on ADI-PEG 20 versus 10.4% on placebo, none related to therapy. Post hoc analyses of arginine assessment at 4, 8, 12 and 16 weeks, demonstrated a trend of improved OS for those with more prolonged arginine depletion. Conclusion: ADI-PEG 20 monotherapy did not demonstrate an OS benefit in second line setting for HCC. It was well tolerated. Strategies to enhance prolonged arginine depletion and synergize the effect of ADI-PEG 20 are underway. Clinical Trial number: www.clinicaltrials.gov (NCT 01287585).

Periodontitis and dental scaling associated with pyogenic liver abscess: A population-based case-control study.

BACKGROUND AND OBJECTIVES: The purpose of this study was to investigate the relationship between periodontitis, dental scaling (DS) and pyogenic liver abscesses (PLAs). MATERIAL AND METHODS: A nationwide population-based case-control study was applied using data from the National Health Insurance Research Database in Taiwan. We identified and enrolled 691 PLA patients, who were individually matched by age and sex to 2764 controls. RESULTS: Conditional logistic regression was applied to estimate adjusted odds ratios (aORs) in patients with exposure to periodontitis and DS before PLA. After adjusting for other confounding factors, periodontitis remained a risk factor for PLA among patients aged 20-40 years, with an aOR of 2.31 (95% confidence interval [CI] = 1.37-3.90, P = .0018). In addition, the average aOR for PLA was significantly lower among patients with one DS (aOR = 0.76, 95% CI = 0.59-0.96) and more than one DS (aOR = 0.61, 95% CI = 0.39-0.95) within 1 year before the index date. CONCLUSION: According to these results, we concluded that adult patients with periodontitis aged <50 years old are more at risk for PLA than controls, particularly when they have no DS. Moreover, from 20 years of age, non-periodontal patients subjected to at least 2 DS per year are less at risk for PLA than controls.

The effectiveness of a saline mouth rinse regimen and education programme on radiation-induced oral mucositis and quality of life in oral cavity cancer patients: A randomised controlled trial.

Radiation therapy (RT) and concurrent chemotherapy RT (CCRT) generate radiation-induced oral mucositis (OM) and lower quality of life (QOL). This study assessed the impact of a saline mouth rinse regimen and education programme on radiation-induced OM symptoms, and QOL in oral cavity cancer (OCC) patients receiving RT or CCRT. Ninety-one OCC patients were randomly divided into a group that received saline mouth rinses and an education programme and a control group that received standard care. OM symptoms and QOL were assessed with the WHO Oral Toxicity Scale, MSS-moo and UW-QOL. Data were collected at the first postoperative visit to the radiation department (T0) and at 4 weeks and 8 weeks after beginning RT or CCRT. Patients in both groups had significantly higher levels of physical and social-emotional QOL at 8 weeks after beginning RT or CCRT compared to the first visit. Patients in the saline rinse group had significantly better physical and social-emotional QOL as compared to the standard care group at 8 weeks. Radiation-induced OM symptoms and overall QOL were not different between the groups. We thus conclude the saline rinse and education programme promote better physical and social-emotional QOL in OCC patients receiving RT/CCRT.

2,3,5,4'-Tetrahydroxystilbene-2-O-ß-glucoside potentiates self-renewal of human dental pulp stem cells via the AMPK/ERK/SIRT1 axis.

AIM: To evaluate the effect of 2,3,5,4'-tetrahydroxystilbene-2-O-ß-D-glucoside (THSG) on cell proliferation and examine the mechanisms of THSG-enhanced proliferative potential in human dental pulp stem cells (hDPSC). METHODOLOGY: After treatment with THSG, hDPSC were collected. Cell viability was determined by MTS assay, while messenger RNA (mRNA) expressions of proliferation and stem cell markers were analyzed using real-time PCR. Flow cytometry was also conducted to analysis protein expression of stem cell markers. A colony-forming unit assay of hDPSC was carried out. Cellular telomerase activity was also identified using real-time PCR. In addition, proliferation-related proteins involved in the effects of THSG on hDPSC were analyzed by Western blotting. Data were analyzed using one-way analysis of variance and two-tailed Student's t-test. RESULTS: Cell viability, colony-forming rates and telomerase activities of hDPSCs were enhanced after THSG treatment. mRNA expressions of proliferation markers (including expressions of NAD+-dependent histone deacetylase sirtuin 1 (SIRT1), proliferating cell nuclear antigen (PCNA), cyclin D1 and ribonucleotide reductase subunit M2 (RRM2)) increased significantly after THSG treatment (P < 0.05). Treatment with THSG for 3 h significantly augmented SIRT1 protein expression (P < 0.05). Furthermore, activities of proliferation-related proteins (including AMP-activated protein kinase (AMPK) and extracellular signal-regulated kinase (ERK) had also significantly increased at 3 h (P < 0.05). After THSG treatment, increased gene and protein expressions of pluripotent-like stem cell markers (including NANOG, OCT4, and SOX2) were observed. CONCLUSIONS: 2,3,5,4'-Tetrahydroxystilbene-2-O-ß-glucoside treatment enhanced the renewal ability and proliferative potential of hDPSCs via the AMPK/ERK/SIRT1 axis, which may provide a novel autogenic cell-based therapeutic strategy in regenerative dentistry.

Meta-analysis of brain mechanisms of chewing and clenching movements.

Functional magnetic resonance imaging (fMRI) is widely used for investigating brain activation patterns associated with chewing and clenching movements. Whether studies consistently identify similar brain loci engaged in these movements remains unknown. We investigated the consistency with which specific brain loci were reported to be activated during teeth-occluding movements, using the activation likelihood estimation (ALE) meta-analysis. Twenty fMRI studies that used fMRI to investigate brain activation during a chewing or clenching task in healthy participants were included. Data from the selected studies were pooled, and ALE methods were used to estimate the likelihood of finding a locus associated with the movements. We found that (i) The bilateral primary motor cortex/supplementary motor area/thalamus, the right primary somatosensory cortex (S1)/secondary somatosensory cortex and the posterior cerebellum (lobule VI) have been identified as reliable loci that show consistently activation when teeth occlude. (ii) The right S1 showed a significant likelihood of activation associated with both chewing and clenching, while the left S1 showed a greater likelihood of activation in chewing than in clenching. (iii) Both younger and older participants showed a significant likelihood of activation in the cerebellum. No significant cluster was identified in the contrast analysis. The fMRI studies reliably identified the sensorimotor cortex, the thalamus and the cerebellum as brain loci associated with chewing and clenching and illustrated a differential activation pattern between chewing and clenching. These findings support the use of fMRI as a potential tool for assessing brain activation patterns related to oral sensorimotor functions in humans.

Experimental studies of thermal environment and contaminant transport in a commercial aircraft cabin with gaspers on.

Gaspers installed in commercial airliner cabins are used to improve passengers' thermal comfort. To understand the impact of gasper airflow on the air quality in a cabin, this investigation measured the distributions of air velocity, air temperature, and gaseous contaminant concentration in five rows of the economy-class section of an MD-82 commercial aircraft. The gaseous contaminant was simulated using SF6 as a tracer gas with the source located at the mouth of a seated manikin close to the aisle. Two-fifths of the gaspers next to the aisle were turned on in the cabin, and each of them supplied air at a flow rate of 0.66 l/s. The airflow rate in the economy-class cabin was controlled at 10 l/s per passenger. Data obtained in a previous study of the cabin with all gaspers turned off were used for comparison. The results show that the jets from the gaspers had a substantial impact on the air velocity and contaminant transport in the cabin. The air velocity in the cabin was higher, and the air temperature slightly more uniform, when the gaspers were on than when they were off, but turning on the gaspers may not have improved the air quality.

Nasotracheal intubation in patients with limited mouth opening: a comparison between fibreoptic intubation and the Trachway®.

In patients with limited mouth opening, traditional laryngoscopy and videolaryngoscopes are not useful when performing nasotracheal intubation. Eighty patients with limited mouth opening who required nasotracheal intubation were randomly assigned to either fibreoptic intubation (n = 40) or the Trachway(®) (n = 40). Using the modified nasal intubation difficulty scale, 22 (55%) patients who received fibreoptic intubation were categorised as no difficulty compared with 40 (100%) patients in the Trachway group (p < 0.001). Mean (SD) total intubation time was 71.8 (23.3) s in patients who received fibreoptic intubation compared with 35.4 (9.8) s in the Trachway group (p < 0.001). We conclude that the Trachway technique for nasotracheal intubation is quicker and easier compared with fibreoptic intubation in patients with limited mouth opening.

Clarifying the mechanism of effect of the Bionator for treatment of maxillary protrusion: A percentile growth study.

AIM: The reported effects of Bionator treatment in patients with mandibular retrognathism are conflicting. This study evaluated the changes in craniofacial morphology resulting from treatment with a Bionator, based on measurement percentiles previously reported, to clarify the mechanism of the effect of this commonly used functional device. MATERIALS AND METHODS: Study Design: Retrospective. SETTING: A private orthodontic clinic. PARTICIPANTS: Forty-two children (mean age, 10.13 years) requiring treatment with a Bionator for Class II malocclusion (mandibular retrognathism). Children were randomly assigned to a Bionator group with or without an expansion screw. Measurements on lateral cephalometric radiographs were taken before and upon completion of Bionator treatment. All parameters measured were characterised according to the measurement percentiles previously reported. Each parameter was compared before and after treatment for all patients and for each treatment group using Wilcoxon's test. RESULTS: No significant differences in cranial length or mandibular body length were seen in any of the 3 groups, but anterior cranial base length and maxillary length were significantly decreased while mandibular ramus height and mandibular length were significantly increased after treatment in the Bionator with expansion screw group and in the all-patient group. CONCLUSIONS: The findings suggest that treatment with a Bionator with expansion screw during the growth and development stage results in increased mandible length and ramus height and inhibits the growth of the maxilla and anterior cranial base bone.

The effect of 8 or 5 years of denosumab treatment in postmenopausal women with osteoporosis: results from the FREEDOM Extension study.

UNLABELLED: The FREEDOM study and its Extension provide long-term information about the effects of denosumab for the treatment of postmenopausal osteoporosis. Treatment for up to 8 years was associated with persistent reduction of bone turnover, continued increases in bone mineral density, low fracture incidence, and a favorable benefit/risk profile. INTRODUCTION: This study aims to report the results through year 5 of the FREEDOM Extension study, representing up to 8 years of continued denosumab treatment in postmenopausal women with osteoporosis. METHODS: Women who completed the 3-year FREEDOM study were eligible to enter the 7-year open-label FREEDOM Extension in which all participants are scheduled to receive denosumab, since placebo assignment was discontinued for ethical reasons. A total of 4550 women enrolled in the Extension (2343 long-term; 2207 cross-over). In this analysis, women in the long-term and cross-over groups received denosumab for up to 8 and 5 years, respectively. RESULTS: Throughout the Extension, sustained reduction of bone turnover markers (BTMs) was observed in both groups. In the long-term group, mean bone mineral density (BMD) continued to increase significantly at each time point measured, for cumulative 8-year gains of 18.4 and 8.3 % at the lumbar spine and total hip, respectively. In the cross-over group, mean BMD increased significantly from the Extension baseline for 5-year cumulative gains of 13.1 and 6.2 % at the lumbar spine and total hip, respectively. The yearly incidence of new vertebral and nonvertebral fractures remained low in both groups. The incidence of adverse and serious adverse events did not increase over time. Through Extension year 5, eight events of osteonecrosis of the jaw and two events of atypical femoral fracture were confirmed. CONCLUSIONS: Denosumab treatment for up to 8 years was associated with persistent reductions of BTMs, continued BMD gains, low fracture incidence, and a consistent safety profile.

Evaluation of two chlorhexidine-alcohol-based skin disinfectants in blood donation setting.

BACKGROUND: Source reduction is important in minimizing bacterial-contaminated risk of blood products, but previous evaluation of chlorhexidine (CHX) was confounded by inability of Tween and lecithin to neutralize CHX. The study aims to address this limitation and also evaluates the effectiveness of two CHX­alcohol-based skin disinfectants in blood donation setting. METHODS: A two-stage observational study was conducted. A single step 2% chlorhexidine gluconate/70% isopropyl alcohol brush (CHX/IPA-1) was first compared with current skin disinfection procedure consisting of sequential application of 10% povidone-iodine and 70% isopropyl alcohol (PI/IPA). Standard plates with conventional neutralizers (0·3% Tween-80, 0·1% lecithin) were used to enumerate residual bacterial counts. Then, CHX/IPA-1 was compared with another applicator CHX/IPA-2 with identical disinfectant contents using in-house plates with neutralizers (3% Tween-80, 0·3% lecithin, 0·1% histidine, 0·5% sodium thiosulphate, 3% saponin, 1% ether sulphate) having enhanced ability to neutralize CHX. RESULTS: All three products were found to reduce plate counts by > 2 log10 after disinfection. The CHX/IPA-1 group gave fewer residual bacterial growth on standard plates than PI/IPA group (5·9% vs. 61·7%, P < 0·001). With the use of in-house plates, residual bacterial growth was of no difference in both CHX/IPA-1 and CHX/IPA-2 groups (42·5% vs. 49·4%, P = 0·26). CONCLUSION: Good efficacy was observed with one-stage application of CHX/IPA in predonation skin disinfection and it could replace PI/IPA. However, the efficacy of CHX/IPA could be grossly overestimated in testing with standard plates because of insufficient neutralization

Simplified models for exhaled airflow from a cough with the mouth covered.

UNLABELLED: Covering a cough can be useful in reducing the transmission of airborne infectious diseases. However, no simple method is available in the literature for predicting the exhaled airflow from a cough with the mouth covered. This investigation used smoke to visualize the airflow exhaled by 16 human subjects. Their mouths were covered by a tissue, a cupped hand, a fist, and an elbow with and without a sleeve. This study then developed simplified models for predicting the airflow on the basis of the smoke visualization data. In addition, this investigation performed numerical simulations to assess the influence of mouth coverings on the receptor's exposure to exhaled particles. It was found that covering a cough with a tissue, a cupped hand, or an elbow can significantly reduce the horizontal velocity and cause the particles to move upward with the thermal plumes generated by a human body. In contrast with an uncovered cough, a covered cough or a cough with the head turned away may prevent direct exposure. PRACTICAL IMPLICATIONS: This study developed simplified models for predicting the exhaled airflow from a cough with the mouth covered. The proposed models can easily be used to investigate the risk of transmission of airborne infectious diseases in enclosed environments.

Fatigue life enhancement of NiTi rotary endodontic instruments by progressive reciprocating operation.

AIM: To evaluate the effect of reciprocating amplitude and progressive angular increment on fatigue life enhancement of NiTi rotary endodontic instruments. METHODOLOGY: ProTaper F2 instruments were operated in steel artificial canals with both stationary reciprocating (SR) and progressive reciprocating (PR) motions. The SR motions involved symmetric to and fro reciprocation of ± 180(o) , ± 135(o) , ± 90(o) , ± 60(o) and ± 45(o) . The PR motions were ± 45(o) stationary motion superimposed with angular increments of 7(o) , 11(o) , 22.5(o) or 31(o) whenever an instrument completed 1, 10 or 30 reciprocating cycles (rc). The fatigue lives were compared with those under continuous rotation (CR) and a reciprocating operation with a forward 144(o) and backward 72(o) motion proposed by Yared (2008). The statistical significance of these operating modes on fatigue life was examined using one way anova and post hoc Tukey's tests at P = 0.05. Fractographic analysis was also applied to probe the fracture mechanisms of different rotation motions. RESULTS: Fatigue life increased with decreasing reciprocating amplitude. Operating in the SR increased fatigue life by 355% over that in the CR. Except for the 22.5(o) increment, all PR motions yielded longer fatigue lives than the SR motion. A progressive reciprocating operation with a ± 45(o) reciprocating amplitude and a + 7(o) progressive angular increment every 10 reciprocating cycles (± 45(o) /10rc/+7(o) ) increased fatigue life by 990% over that in the CR motion. In terms of life enhancement over the CR motion, the larger the curvature the less are the differences between different movements. Single crack initiation sites were found in the CR and SR motions, while three crack initiation sites were typical in the ± 45(o) /10rc/+7(o) motion. CONCLUSIONS: Fatigue life increased with decreasing reciprocating amplitude in stationary reciprocation. A progressive reciprocating operation with ± 45(o) /10rc/+7(o) motion led to significant fatigue life enhancement and multiple fatigue crack initiation in NiTi endodontic instruments.

Application of a functional marker for the effect of cryoprotectant agents on gorgonian coral (Junceella juncea and J. fragilis) sperm sacs.

BACKGROUND: The establishment of coral sperm repositories which retain good post-rewarming viability and fertility play a vital role in species conservation. OBJECTIVE: This study aimed at obtaining baseline information regarding the effects of cryoprotectant agents (CPAs) on gorgonian coral (Junceella juncea and J. fragilis) sperm sacs. METHODS: The adenosine triphosphate assay was used to determine the energy level of the gorgonian sperm sacs as an indicator of sperm viability after exposure to cryoprotectants. RESULTS: The 'no observed effect concentrations' (NOECs) of methanol, dimethyl sulfoxide (DMSO), polypropylene glycol (PG), ethylene glycol (EG) and glycerol for J. juncea sperm sacs were 3 M, 3 M, 1 M, 2 M and 1 M respectively after 20 min exposure; whilst the NOECs for J. fragilis oocytes were 2 M, 3 M, 1 M, 2 M and 2 M, respectively. Methanol and DMSO had the least impact. PG was the most toxic CPA after 10 min exposure. ATP content of J. juncea and J. fragilis sperm sacs did not differ significantly from the control with incubation times of 10-20 min with 2 M EG. However, ATP content dropped significantly after exposing sperm sacs to 2 M EG for 40 min with average values of 2.34 +/- 0.12 and 1.97 +/- 0.48 microg/ml respectively. ATP content for J. juncea and J. fragilis sperm sacs was significantly decreased to 1.79 +/- 0.31 and 2.40 +/- 0.36 microg/ml after 20 min incubation in 2 M PG when compared to the control with 2.98 +/- 0.16 and 4.14 +/- 0.42 microg/ml respectively. Normalized ATP content for sperm sacs of two different gorgonian coral after incubation in methanol, DMSO, PG, EG and glycerol showed that J. juncea sperm sacs were slightly less tolerant to CPAs compared to J. fragilis sperm sacs. CONCLUSIONS: DMSO or methanol can be considered as efficient CPAs for gorgonian sperm sacs cryopreservation. The ATP luminescence assay provided sensitive and rapid quantification of mitochondrial activity in gorgonian coral sperm sacs. The study on the impact of CPA will contribute to the development of a cryopreservation protocol for coral sperm conservation.

[Introduction and interpretation of The European Society of Endodontology S3-level clinical practice guideline for treatment of pulpal and apical disease].

The European Society of Endodontology published the S3-level clinical practice guideline for the treatment of pulpal and apical disease in October 2023, which provides best current therapeutic strategies supported by scientific evidences. The guideline was divided into four parts: the diagnosis and treatment of pulpitis, diagnosis and nonsurgical treatment of apical periodontitis, surgical treatment of apical periodontitis, and regenerative treatment. This article aims to introduce and interpret the guideline, and to better manage patients with pulpitis and apical periodontitis for preserving teeth over a patient's lifetime in China.