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Osteomyelitis is a limb- and life-threatening orthopedic infection predominantly caused by Staphylococcus aureus biofilms. Bone infections are extremely challenging to treat clinically. Therefore, we have been designing, synthesizing, and testing novel antibiotic conjugates to target bone infections. This class of conjugates comprises bone-binding bisphosphonates as biochemical vectors for the delivery of antibiotic agents to bone minerals (hydroxyapatite). In the present study, we utilized a real-time impedance-based assay to study the growth of Staphylococcus aureus biofilms over time and to test the antimicrobial efficacy of our novel conjugates on the inhibition of biofilm growth in the presence and absence of hydroxyapatite. We tested early and newer generation quinolone antibiotics (ciprofloxacin, moxifloxacin, sitafloxacin, and nemonoxacin) and several bisphosphonate-conjugated versions of these antibiotics (bisphosphonate-carbamate-sitafloxacin (BCS), bisphosphonate-carbamate-nemonoxacin (BCN), etidronate-carbamate-ciprofloxacin (ECC), and etidronate-carbamate-moxifloxacin (ECX)) and found that they were able to inhibit Staphylococcus aureus biofilms in a dose-dependent manner. Among the conjugates, the greatest antimicrobial efficacy was observed for BCN with an MIC of 1.48 µg/mL. The conjugates demonstrated varying antimicrobial activity depending on the specific antibiotic used for conjugation, the type of bisphosphonate moiety, the chemical conjugation scheme, and the presence or absence of hydroxyapatite. The conjugates designed and tested in this study retained the bone-binding properties of the parent bisphosphonate moiety as confirmed using high-performance liquid chromatography. They also retained the antimicrobial activity of the parent antibiotic in the presence or absence of hydroxyapatite, albeit at lower levels due to the nature of their chemical modification. These findings will aid in the optimization and testing of this novel class of drugs for future applications to pharmacotherapy in osteomyelitis.

Advances in the design of potential bone-selective drugs for the treatment of various bone-related diseases are creating exciting new directions for multiple unmet medical needs. For bone-related cancers, off-target/non-bone toxicities with current drugs represent a significant barrier to the quality of life of affected patients. For bone infections and osteomyelitis, bacterial biofilms on infected bones limit the efficacy of antibiotics because it is hard to access the bacteria with current approaches. Promising new experimental approaches to therapy, based on bone-targeting of drugs, have been used in animal models of these conditions and demonstrate improved efficacy and safety. The success of these drug-design strategies bodes well for the development of therapies with improved efficacy for the treatment of diseases affecting the skeleton. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

The bisphosphonates ((HO)

Bacterial cellulose (BC), produced by Komagataeibacter xylinus, has numerous applications to medicine and industry. A major limitation of BC use is relatively low production rates and high culturing media costs. By supplementing culture media with 1% vegetable oil, we achieved BC yield exceeding 500% over the yield obtained in standard media. BC properties were similar to cellulose cultured in standard methods with regard to cytotoxicity but displayed significantly higher water swelling capacity and mechanical strength. As we demonstrated herein, this significantly increased BC yield is the result of microscopic and macroscopic physiochemical processes reflecting a complex interaction between K. xylinus biophysiology, chemical processes of BC synthesis, and physiochemical forces between BC membranes, oil and culturing vessel walls. Our findings have significant translational implications to biomedical and clinical settings and can be transformative for the cellulose biopolymer industry.

An opportunistic infection (OI) is a disease of microbial cause or pathogenesis generally thought to occur in hosts with weakened immunity. Oral OIs are associated with many risk factors and pathogens. Causative organisms for oral OIs have unique modes of transmission. The clinical presentation of oral OIs is heterogeneous and diagnosis can be challenging. Therefore, laboratory identification of causative pathogens is useful for definitive diagnosis and targeted therapeutics, and can be achieved by biological, serologic, histologic, and/or molecular methods. Clinical risk assessment and history with review of systems, and accurate diagnosis, treatment, and follow-up, are essential.

Chronic leg ulceration is a disease usually associated with other comorbidities, and significantly reduces patient quality of life. Infected leg ulcers can lead to limb-threatening sequelae or mortality. Leg ulcerations are colonized by a number of microbes that are able to cause life-threating infections in susceptible patients. Wound exudate is a body fluid that collects metabolites from patient eukaryotic cells and from prokaryotic bacterial communities inhabiting the wound. This study aimed at identification of metabolites in exudates collected from chronic leg ulcers, and correlation of this metabolome with patient comorbidities and microbiological status of the wound. By means of NMR spectroscopy we detected 42 metabolites of microbial or patient origin. The metabolites that were in abundance in exudates analyzed were lactate, lysine, and leucine. Metabolites were associated with the presence of neutrophils in wounds and destruction of high quantities of microbes, but also with hypoxia typical for venous insufficiency. The combination of nuclear magnetic resonance spectroscopy technique and partial least squares discriminant analysis allowed us to further discriminate groups of metabolites with regards to potential clinical meaning. For example, to discriminate between S.aureus versus all other isolated microbial species, or between patients suffering from type I or II diabetes versus patients without diabetes. Therefore, wound exudate seems to be highly applicable material for discriminant analysis performed with the use of NMR technique to provide for rapid metabolomics of chronic wound status.

Oral lichen planus (OLP) is a common chronic inflammatory disease affecting the oral mucosa. The pathogenesis of OLP is incompletely understood but is thought to be related to the immune system. As the oral cavity is a major reservoir and transmission gateway for bacteria, viruses, and fungi, the microbial composition of the oral cavity could play a role in the pathogenesis of OLP. However, due to limitations of analytic technology and incomplete knowledge of the microbial community in the oral cavity, it is not yet clear which pathogens are associated with OLP. Next-generation sequencing (NGS) is a powerful tool that can help to identify pathogens for many infectious diseases. In this study, we compared host cell gene expression profiles and microbial profiles from OLP patients and matched healthy individuals. We identified activation of the hepatocyte nuclear factor alpha (HNF4A) network in OLP patients and potential pathogens, includingCorynebacterium matruchotii, Fusobacterium periodonticum, Streptococcus intermedius, Streptococcus oralis, andPrevotella denticola. P. denticolais capable of activating the HNF4A gene network. Our findings shed light on the previously elusive association of OLP with various diseases like hepatitis, and indicate that OLP is a T-helper type 17 (Th17)-mediated mucosal inflammatory process. The molecular pathways and microbes identified here can inform future investigations into OLP pathogenesis and development of novel therapeutics for OLP treatment.

Infections of the oral cavity are caused by multicellular communities of microbes, referred to as biofilms. Due to the high tolerance of biofilms to antibiotics and specific conditions within the oral cavity, there is an ongoing search for carriers that are able to deliver high local concentrations of potent antimicrobials that can eradicate pathogenic biofilms. Bacterial cellulose, owing to its high flexibility, absorbance, and release potential, meets these demands. In this work we chemisorbed bacterial cellulose with antiseptics containing povidone-iodine or polihexanide and analyzed their ability to eradicate in vitro biofilms formed by oral pathogens, such as Aggregatibacter actinomycetemcomitans, Enterococcus faecalis, Candida albicans, Streptococcus mutans, Staphylococcus aureus, and Pseudomonas aeruginosa. In tests performed by means of standard laboratory methods and with a long contact time (24 h), all antiseptics released from the cellulose dressings displayed a very high antibiofilm efficacy. On the other hand, when conditions imitating the oral cavity were used and cellulose dressings were applied for a 0.5&ndash, 1 h contact time, the antiseptics released from the dressings displayed lower, though still acceptable, activity. Our findings indicate that besides species-specific resistance to particular antiseptic agents, environmental and experimental settings play an essential role in outcomes. Finally, in a proof-of-concept experiment performed in an oral cavity typodont model, we demonstrated the high flexibility and adhesiveness of antiseptic-containing cellulose dressings. Our novel findings, if developed in further studies, may lead to the introduction of new types of dressings that are able to efficiently deal with biofilm infections of the oral cavity.

Studies of the potential role of bisphosphonates in dentistry date back to physical chemical research in the 1960s, and the genesis of the discovery of bisphosphonate pharmacology in part can be linked to some of this work. Since that time, parallel research on the effects of bisphosphonates on bone metabolism continued, while efforts in the dental field included studies of bisphosphonate effects on dental calculus, caries, and alveolar bone loss. While some utility of this drug class in the dental field was identified, leading to their experimental use in various dentrifice formulations and in some dental applications clinically, adverse effects of bisphosphonates in the jaws have also received attention. Most recently, certain bisphosphonates, particularly those with strong bone targeting properties, but limited biochemical effects (low potency bisphosphonates), are being studied as a local remedy for the concerns of adverse effects associated with other more potent members of this drug class. Additionally, low potency bisphosphonate analogs are under study as vectors to target active drugs to the mineral surfaces of the jawbones. These latter efforts have been devised for the prevention and treatment of oral problems, such as infections associated with oral surgery and implants. Advances in the utility and mechanistic understanding of the bisphosphonate class may enable additional oral therapeutic options for the management of multiple aspects of dental health.

Background Proliferative fasciitis is a benign and reactive lesion involving fibroblasts in the subcutaneous tissues and deep fascia, with a rare occurrence in the head and neck region. It is considered a variant of nodular fasciitis, which could involve trauma as an etiology. Proliferative fasciitis mostly occurs in adults, but cases in children have been reported. Clinically, it can present as an aggressive lesion with pain or no symptoms, mimicking sarcomas. Case Summary We report a case of a 53-year-old woman who presented to our clinic for an evaluation of a reddish lesion of the right mandibular gingiva around the molar areas with a relatively rapid onset. The patient had prediabetes with moderate oral hygiene and no other significant medical history.Intraoral examination revealed a poorly circumscribed gingival lesion on the posterior, Conclusions Because proliferative fasciitis has not been reported in the oral cavity, to our knowledge, and because it poses a diagnostic challenge and can mimic malignancies, it is essential to know the salient diagnostic features to avoid aggressive treatment in patients presenting with such lesions in the oral cavity.

The purpose of this systematic review and meta-analysis was to compare the prognosis of patients with p16 expressing oropharyngeal squamous cell cancers to patients with p16 non-expressing cancers. Clinical outcomes that were evaluated included overall survival, local recurrence, disease-free survival, disease-specific survival, and event-free survival. The following electronic databases were searched: Cochrane Library, MEDLINE (via Pubmed), and Web of Science. Publications were restricted to English language. Studies were limited to controlled clinical trials on the survival rates of patients with oropharyngeal tumors that were p16 expressing, compared to patients with p16 non-expressing tumors, and at least one clinical endpoint reported by trial authors (hazard ratios). Specific ascertainment criteria were applied for inclusion and exclusion of eligible studies. Data was independently extracted in duplicate. This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analysis PRISMA checklist. Risk of bias was assessed for all included studies, and disagreements between review authors were discussed until an agreement was reached. Eighteen studies were included for final review and meta-analysis. The subgroup meta-analyses, which included survival and recurrence data, showed significantly favorable outcomes for patients with p16 expressing tumors. There is strong evidence to support that patients with p16 expressing oropharyngeal squamous cell cancers have favorable clinical outcomes and prognosis.

The gold-standard periodontal probe is an aging tool that can detect periodontitis and monitor gingival health but is highly error-prone, does not fully characterize the periodontal pocket, and causes pain. Photoacoustic imaging is a noninvasive technique that can address these limitations. Here, a range of ultrasound frequencies between 16–40 MHz were used to image the periodontium and a contrast medium based on cuttlefish ink was used to label the pockets. A 40 MHz ultrasound frequency could spatially resolve the periodontal anatomy, including tooth, gum, gingival margin, and gingival thickness of tooth numbers 7–10 and 22–27. The photoacoustic-ultrasound measurements were more precise (0.01 mm) than those taken with physical probes by a dental hygienist. Furthermore, the full geometry of the pockets could be visualized with relative standard deviations of 10% (n = 5). This study shows the potential for non-invasive monitoring of periodontal health with photoacoustic-ultrasound imaging in the dental clinic. Keywords: Photoacoustic imaging, Periodontal disease, Diagnosis, Gingival thickness, Pocket depth, Periodontal charting, Melanin nanoparticles

The purpose of this systematic review with meta-analysis was to assess the effectiveness of dental interventions in preventing or reducing the incidence of medication-related osteonecrosis of the jaw (MRONJ) in cancer patients receiving antiresorptive therapy, compared to similar control groups receiving no intervention. Randomized controlled trials (RCT), case-controls and cohorts on cancer patients with primary outcome being the prevalence of MRONJ were included. Four electronic databases were searched (Cochrane Library, PubMed, EMBASE and Web of Science) up to February 12, 2018. A total of 409 abstracts were assessed and one case-control, one RCT and four cohort studies with 2332 cancer patients met our inclusion criteria. Risk of bias analysis followed Cochrane's handbook. Risk of bias was unclear for the case-control study and high risk for the RCT and all cohort studies. Five studies utilized preventive measures consisting of an initial examination and performing all necessary dental treatment before patients initiated antiresorptive therapy; one study used specialized post-extraction protocols utilizing plasma-rich in growth factors (PRGF) on cancer patients receiving antiresorptive therapy. Though dental preventive measures decreased MRONJ incidence by 77.3% in six studies with 2332 cancer patients (95% CI = 47.4–90.2%; p = .001) compared to control groups, quality of the evidence was low due to high or unclear risk of bias and the observational nature of five of the included studies. In conclusion, high-quality long-term prospective large sample size studies are needed to confirm these results due to high risk of bias and heterogeneous interventions. No funding.

Brain abscesses are rare but potentially deadly complications of odontogenic infections. This phenomenon has been described mainly in the form of case reports, as large-scale studies are difficult to perform. We compiled a total of 60 previously published cases of such a complication to investigate the predisposing factors, microbiology, and clinical outcomes of intracranial abscesses of odontogenic origin. A systematic review of the literature using the PubMed database was performed. Men accounted for 82.1% of cases, and the mean age was 42.1 years. Caries with periapical involvement and periodontitis were the two most common intra-oral sources, and wisdom tooth extraction was the most common preceding dental procedure. In 56.4% of cases, there were obvious signs of dental disease prior to development of intracranial infection. Commonly implicated microorganisms included Streptococcus viridans (especially the anginosus group), Actinomyces, Peptostreptococcus, Prevotella, Fusobacterium, Aggregatibacter actinomycetemcomitans and Eikenella corrodens. There was an 8.3% mortality rate. Intracranial abscesses can form anywhere within the brain, and appear unrelated to the side of dental involvement. This suggests that hematogenous spread is the most likely route of dissemination.

It is widely thought that inflammation and osteoclastogenesis result in hydroxyapatite (HA) resorption and sequestrum formation during osseous infections, and microbial biofilm pathogens induce the inflammatory destruction of HA. We hypothesized that biofilms associated with infectious bone disease can directly resorb HA in the absence of host inflammation or osteoclastogenesis. Therefore we developed an in vitro model to test this hypothesis.Customized HA discs were manufactured as a substrate for growing clinically relevant biofilm pathogens. Single-species biofilms of Streptococcus mutans, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans and mixed-species biofilms of C albicans plus S mutans were incubated on HA discs for 72 hours to grow mature biofilms. Three different non-biofilm control groups also were established for testing. HA discs were then evaluated by means of scanning electron microscopy, micro-computed tomography metrotomography, x-ray spectroscopy, and confocal microscopy with planimetric analysis. In addition, quantitative cultures and pH assessment were performed. Analysis of variance was used to test for significance between treatment and control groups.All investigated biofilms were able to cause significant (P.05) and morphologically characteristic alterations in HA structure as compared with controls. The highest number of alterations observed was caused by mixed biofilms of C albicans plus S mutans. S mutans biofilm incubated in medium with additional sucrose content was the most detrimental to HA surfaces among single-species biofilms.Our findings suggest that direct microbial resorption of bone is possible in addition to immune-mediated destruction, which has important translational implications for the pathogenesis of chronic bone infections and for targeted antimicrobial therapeutics.

Next generation sequencing (NGS) provides an opportunity to detect viral species from RNA-seq data on human tissues, but existing computational approaches do not perform optimally on clinical samples. We developed a bioinformatics method called VirTect for detecting viruses in neoplastic human tissues using RNA-seq data. Here, we used VirTect to analyze RNA-seq data from 363 HNSCC (head and neck squamous cell carcinoma) patients and identified 22 HPV-induced HNSCCs. These predictions were validated by manual review of pathology reports on histopathologic specimens. Compared to two existing prediction methods, VirusFinder and VirusSeq, VirTect demonstrated superior performance with many fewer false positives and false negatives. The majority of HPV carcinogenesis studies thus far have been performed on cervical cancer and generalized to HNSCC. Our results suggest that HPV-induced HNSCC involves unique mechanisms of carcinogenesis, so understanding these molecular mechanisms will have a significant impact on therapeutic approaches and outcomes. In summary, VirTect can be an effective solution for the detection of viruses with NGS data, and can facilitate the clinicopathologic characterization of various types of cancers with broad applications for oncology.Significance StatementWe developed a new bioinformatics tool, and reported the new inside of HPV carcinogenesis mechanism in HPV-induced head and neck squamous cell carcinoma (HNSCC). This novel bioin-formatics tool and the new knowledge of HPV-induced HNSCC will facilitate the development of target therapies for treating HNSCC.

Summary The periodontal pathogen Aggregatibacter actinomycetemcomitans is known to elicit systemic immune response in infected host, and occasionally causes non-oral infections. Detailed information on its immunopathological responses and the involvement of bacterial virulence factors remains to be elucidated. The aim of this study was to assess the systemic immune response to A. actinomycetemcomitans oral infection. We used an animal model that simulates systemic dissemination of the bacteria by injecting live wild type (WT) D7S-1 and double knockout mutant of leukotoxin and cytolethal distending toxin (ΔltxΔcdt) A. actinomycetemcomitans strains in rat oral mucosa. Draining lymph nodes were examined for Treg and Th17 subsets and their associated mediators. An increase in the proportion of Th17 cells and decrease in Treg cells over the experimental period of 3 weeks were similarly observed for rats challenged with WT and ΔltxΔcdt. Significant up and down-regulation of proinflammatory cytokines in the Th17 gene pathway was noted, as well as several qualitative differences between WT and ΔltxΔcdt. Furthermore, we observed differential fold regulation in key genes associated with a proinflammatory response in ΔltxΔcdt-inoculated rats relative to D7S-1 group. This suggests that although the knockout of these two virulence factors (ΔltxΔcdt) may suppress certain proinflammatory genes, it causes similar over-expression of other genes compared to D7S-1, indicating a common factor that still remains in the pathogenicity of A. actinomycetemcomins. This article is protected by copyright. All rights reserved.

// Andres Stucky 1 , Parish P. Sedghizadeh 1 , Susan Mahabady 1 , Xuelian Chen 1 , Cheng Zhang 1, 2 , Gang Zhang 1, 3 , Xi Zhang 1, 2 and Jiang F. Zhong 1 1 Division of Periodontology, Diagnostic Sciences and Dental Hygiene, and Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA 2 Department of Hematology and Blood Transfusion, Xinqiao Hospital, Third Military Medical University, Chongqing, P. R. China 3 Department of Oral and Maxillofacial Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, P. R. China Correspondence to: Andres Stucky, email: astucky@usc.edu Parish P. Sedghizadeh, email: sedghiza@usc.edu Xi Zhang, email: zhangxxi@sina.com Keywords: head and neck cancer, squamous cell carcinoma, HNSCC, single-cell genomics, circulating tumor cells Received: April 13, 2017 Accepted: May 10, 2017 Published: May 19, 2017 ABSTRACT Head and neck squamous cell carcinoma (HNSCC) incidence or rates have increased dramatically recently with little improvement in patient outcomes. There is an unmet need in HNSCC to develop reliable molecular markers capable of evaluating patient risks and advising treatments. This review focuses on recent developments in single-cell molecular analysis of cancer, and its applications for HNSCC diagnosis and treatments. For proof of concept, we examined gene expression levels of 62 patients with HNSCC, and correlate the gene expression profiles to single-cell gene expression profiles obtained from a pilot single-cell study of CCR5-positive breast carcinoma cells. The single-cell molecular analyses complemented the lysate data and reveals heterogeneity of oncogenesis pathways with the cancer cell population. Our single-cell molecular analysis indicated that molecular heterogeneity exists in HNSCC and should be addressed in treatment strategy of HNSCC. Single-cell molecular technology can have significant impact on diagnosis, therapeutic decision making, and prognosis of HNSCC.

Introduction The purpose of this study was to evaluate the number of roots and canal morphology of maxillary permanent first molars in a North American population. Methods Three hundred seventeen cases with bilateral maxillary first molars were included. All images from cone-beam computed tomography were carefully reviewed by 2 endodontists. Frequency of number of roots, presence of an additional mesiobuccal canal (MB2), and Vertucci canal type for each root were tabulated. Age, gender, and ethnicity differences were calculated with the χ 2 test. The intra-rater reliability was assessed by using the Cohen kappa statistic. Results The fused root rate was 0.9%. The occurrence of 3-rooted maxillary first molars differed between left and right sides ( P = .03). MB2 occurrence only showed statistically significant differences among age groups ( P = .005). In the mesiobuccal roots, the most common Vertucci classifications of canal types were type IV (2-2, 41.9%), type I (1, 28.3%), and type II (2-1, 26.3%). There was a statistically significant difference in Vertucci classification of canal type among 5 ethnic groups (African American, Asian, Hispanic, Other, and Non-Hispanic white, P Conclusions Cone-beam computed tomography facilitates the identification of root and canal configuration. The information gained about the tooth anatomy and canal morphology before treatment could potentially facilitate root canal therapy.

The connection between antiresorptive medications, like bisphosphonates and denosumab, and osteonecrosis of the jaw has been well studied in the literature. A 10-year retrospective case-control analysis of the patient population at the University of Southern California, Herman Ostrow School of Dentistry, found a robust population of patients of record with a history of bisphosphonate or denosumab use and a significant subset of those patients had medication-related osteonecrosis of the jaw (MRONJ). This study explores the demographic and clinical factors associated with risk for MRONJ in patients taking antiresorptive medications. Multivariate analysis indicated that patients at greatest risk were over 60 years of age, female sex, Asian race, had cancer as a comorbidity, had a history of tooth extraction, and also patients on long-term antiresorptive pharmacotherapy. The findings of this study should help guide clinicians to identify patients at high risk for MRONJ, and thus patients that would benefit from risk reduction and prevention protocols.

Introduction The purpose of this study was to evaluate the reliability and accuracy of cone-beam computed tomographic (CBCT) imaging against the histopathologic diagnosis for the differential diagnosis of periapical cysts (cavitated lesions) from (solid) granulomas. Methods Thirty-six periapical lesions were imaged using CBCT scans. Apicoectomy surgeries were conducted for histopathological examination. Evaluator 1 examined each CBCT scan for the presence of 6 radiologic characteristics of a cyst (ie, location, periphery, shape, internal structure, effects on surrounding structure, and perforation of the cortical plate). Not every cyst showed all radiologic features (eg, not all cysts perforate the cortical plate). For the purpose of finding the minimum number of diagnostic criteria present in a scan to diagnose a lesion as a cyst, we conducted 6 receiver operating characteristic curve analyses comparing CBCT diagnoses with the histopathologic diagnosis. Two other independent evaluators examined the CBCT lesions. Statistical tests were conducted to examine the accuracy, inter-rater reliability, and intrarater reliability of CBCT images. Results Findings showed that a score of ≥4 positive findings was the optimal scoring system. The accuracies of differential diagnoses of 3 evaluators were moderate (area under the curve = 0.76, 0.70, and 0.69 for evaluators 1, 2, and 3, respectively). The inter-rater agreement of the 3 evaluators was excellent (α = 0.87). The intrarater agreement was good to excellent (κ = 0.71, 0.76, and 0.77). Conclusions CBCT images can provide a moderately accurate diagnosis between cysts and granulomas.

Schaudinn C , Jaramillo D , Freire MO , SedghizadehPP , Nguyen A , Webster P , Costerton JW , Jiang C. Evaluation of a nonthermal plasma needle to eliminateex vivo biofilms in root canals of extracted human teeth.International Endodontic Journal. Aim To evaluate the efficacy of a nonthermal plasma(NTP) at atmospheric pressure on ex vivo biofilm inroot canals of extracted teeth.Methodology Intracanal contents from three teethwith root canal infections were collected, pooled andgrown in thirty-five microCT-mapped root canals ofextracted and instrumented human teeth. One groupof teeth was treated with NTP, another with 6%NaOCl and one set was left untreated. The intracanalcontents from twenty-seven teeth (nine teeth in eachgroup) were plated on agar and colony forming unitswere determined. Parametric test of one-way analysisof variance ( ANOVA ) was used to analyse statisticalsignificance. The remaining teeth were cut open,stained with LIVE/DEAD and examined with confo-cal laser scanning microscopy.Results The untreated root canals were coveredwith biofilm of varying thickness. Treatment withnonthermal plasma decreased the number of viablebacteria in biofilms by one order of magnitude, whilstthe NaOCl control achieved a reduction of more thanfour magnitudes. Both the NTP and the NaOCl treat-ment results were significantly different from the neg-ative control (P < 0.05).Conclusion The nonthermal plasma displayed anti-microbial activity against endodontic biofilms in rootcanals, but was not as effective as the use of 6%NaOCl.Keywords: biofilm, Endodontics, micro-CT, non-thermal plasma.

Osteomyelitis is a major problem worldwide and is devastating due to the potential for limb-threatening sequelae and mortality. Osteomyelitis pathogens are bone-attached biofilms, making antibiotic delivery challenging. Here we describe a novel osteoadsorptive bisphosphonate-ciprofloxacin conjugate (BV600022), utilizing a “target and release” chemical strategy, which demonstrated a significantly enhanced therapeutic index versus ciprofloxacin for the treatment of osteomyelitis in vivo. In vitro antimicrobial susceptibility testing of the conjugate against common osteomyelitis pathogens revealed an effective bactericidal profile and sustained release of the parent antibiotic over time. Efficacy and safety were demonstrated in an animal model of periprosthetic osteomyelitis, where a single dose of 10 mg/kg (15.6 µmol/kg) conjugate reduced the bacterial load by 99% and demonstrated nearly an order of magnitude greater activity than the parent antibiotic ciprofloxacin (30 mg/kg, 90.6 µmol/kg) given in multiple doses. Conjugates incorporating a bisphosphonate and an antibiotic for bone-targeted delivery to treat osteomyelitis biofilm pathogens constitute a promising approach to providing high bone-antimicrobial potency while minimizing systemic exposure.

Background Oral mucositis occurs in patients undergoing chemoradiation for cancer treatment. It is believed that colonization of ulcerated mucosa by bacteria, fungi and virus results in secondary infections. The effect of chlorhexidine (CHX) on the incidence and severity of oral mucositis in cancer patients was evaluated in this review. Methods Studies were limited to randomized placebo-controlled trials. Three databases were searched: MEDLINE (via PubMed), Web of Science and the Cochrane Library up to May 25, 2016. Results Ninety-eight abstracts were evaluated by three independent reviewers. Twelve studies met the criteria for inclusion. Four of these studies were assessed at unclear risk of bias and eight of them at high risk. Of the 12 studies, 9 were included in two meta-analyses. Pooled results showed that chlorhexidine did not significantly reduce incidence of mucositis compared to placebo (p=0.129), nor chlorhexidine did significantly reduce the severity of mucositis (p=0.127), though subgroup analysis in the chemotherapy group showed a trend toward significance (p=0.054). Side-effects reported in the included studies were teeth staining and altered taste perception. Conclusions This systematic review found that chlorhexidine is not significantly effective in reducing the severity of mucositis (moderate quality of evidence) nor in preventing the incidence of mucositis (low quality of evidence). However, more studies are needed in patients receiving chemotherapy only, as a positive trend toward significance was found (p=.054). This article is protected by copyright. All rights reserved.

Bone infections are a significant public health burden associated with morbidity and mortality in patients. Microbial biofilm pathogens are the causative agents in chronic osteomyelitis. Research on the pathogenesis of osteomyelitis has focused on indirect bone destruction by host immune cells and cytokines secondary to microbial insult. Direct bone resorption by biofilm pathogens has not yet been seriously considered. In this study, common osteomyelitis pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Streptococcus mutans) were grown as biofilms in multiple in vitro and ex vivo experiments to analyze quantitative and qualitative aspects of bone destruction during infection. Pathogens were grown as single or mixed species biofilms on the following substrates: hydroxyapatite, rat jawbone, or polystyrene wells, and in various media. Biofilm growth was evaluated by scanning electron microscopy and pH levels were monitored over time. Histomorphologic and quantitative effects of biofilms on tested substrates were analyzed by microcomputed tomography and quantitative cultures. All tested biofilms demonstrated significant damage to bone. Scanning electron microscopy indicated that all strains formed mature biofilms within 7 days on all substrate surfaces regardless of media. Experimental conditions impacted pH levels, although this had no impact on biofilm growth or bone destruction. Presence of biofilm led to bone dissolution with a decrease of total volume by 20.17±2.93% upon microcomputed tomography analysis, which was statistically significant as compared to controls (p

We hypothesized that patients with bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) accumulate higher levels of BP in bone than those without BRONJ.Using the Pmetrics package and published data, we designed a population pharmacokinetic model of pamidronate concentration in plasma and bone and derived a toxic bone BP threshold of 0.2 mmol/L. With the model, and using patient individual BP duration and bone mineral content estimated from lean body weight, we calculated bone BP levels in 153 subjects.Mean bone BP in 69 BRONJ cases was higher than in 84 controls (0.20 vs 0.10 mmol/L, P0.001), consistent with the toxic bone threshold of 0.2 mmol/L. BRONJ was also associated with longer duration BP therapy (5.3 vs 2.7 years, P0.001), older age (76 vs 70 years, P0.001), and Asian race (49% vs 14%, P0.001).Our model accurately discriminated BRONJ cases from controls among patients on BP therapy.

Objective Bacterial biofilms play a role in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ). The purpose of this preliminary study was to test the hypothesis that the extracellular filaments observed in biofilms associated with BRONJ contain electrically conductive nanowires. Study Design Bone samples of patients affected by BRONJ were evaluated for conductive nanowires by scanning electron microscopy (SEM) and conductive probe atomic force microscopy (CP-AFM). We created nanofabricated electrodes to measure electrical transport along putative nanowires. Results SEM revealed large-scale multispecies biofilms containing numerous filamentous structures throughout necrotic bone. CP-AFM analysis revealed that these structures were electrically conductive nanowires with resistivities on the order of 20 Ω·cm. Nanofabricated electrodes spaced along the nanowires confirmed their ability to transfer electrons over micron-scale lengths. Conclusions Electrically conductive bacterial nanowires to date have been described only in environmental isolates. This study shows for the first time that these nanowires can also be found in clinically relevant biofilm-mediated diseases, such as BRONJ, and may represent an important target for therapy.

The study aimed at evaluation of various types of alkali rinsing with regard to their efficacy in terms of removal, not only of bacteria but also bacterial metabolites, from cellulose matrices formed by three Komagataeibacter xylinus strains. Moreover, we tested the type of alkali rinsing on membrane cytotoxicity in vitro in fibroblast and osteoblast cells and we compared matrices’ ability to induce oxidative stress in macrophages. We identified 11 metabolites of bacterial origin that remained in cellulose after rinsing. Moreover, our results indicated that the type of alkali rinsing should be adjusted to specific K. xylinus strains that are used as cellulose producers to obtain safe biomaterials in the context of low cytotoxicity and macrophage induction. The findings have translational importance and may be of direct significance to cellulose dressing manufacturers.

Granular cell tumor (GCT) of the oral cavity is a benign lesion. Half of oral GCTs demonstrate pseudocarcinomatous hyperplasia (PCH) of the mucosa which can mimic invasive islands of oral squamous cell carcinoma (SCC). Such similarity can be confusing when diagnosing or evaluating the two conditions, potentially leading to misdiagnosis or misclassification. Indeed, several misdiagnosed cases of oral GCT have been reported in the literature as OSCC or malignant oral GCT that resulted in unnecessary aggressive treatment for the affected patients. The aim of this study was to investigate if the cytokeratin pattern of the PCH can help in differentiating GCT from oral SCC. To distinguish between these two entities, we examined 12 patient specimens of oral GCT-PCH and oral SCC histologically and via immunohistochemistry (IHC) for CK13, CK17 and P75. The results suggest that the cytokeratin profile of PCH is similar to that of oral SCC. Therefore, consideration of IHC findings for epithelial markers alone may lead to erroneous diagnosis; thus, the presence of the granular tumor underneath the PCH and its immunopositivity for P75 or other neural definition markers can be essential to identify the underlying tumor and exclude oral SCC. Finally we recommend more studies on the molecular biology of PCH to understand how it can mimic oral SCC histologically without harboring its malignant phenotype clinically, which could have significant translational potential for understanding invasive oral SCC.

Inactivation kinetics of a nanosecond-pulsed plasma jet against a panel of common pathogenic microorganisms was studied to assist the design and development of nonthermal plasma-based treatment schemes for pathogenic infection control. We evaluated the effectiveness of our cold-plasma in vitro against microbes with varying cell wall and membrane characteristics: the Gram-positive organisms Staphylococcus aureus and Staphylococcus epidermidis, the Gram-negative organisms Pseudomonas aeruginosa and Escherichia coli, and the yeast Candida albicans. We found that all of the organisms tested in this paper were rendered nonculturable (>;99.99%) by the end of the short plasma treatment times ranging from 30 to 180 s. Our results indicate that the pathogenic bacteria and yeast tested in this paper can be effectively rendered noncultivable within seconds using the He/(1%)O2 cold plasma, and that susceptibility to plasma may vary depending on the cell wall and membrane characteristics of the organisms in addition to the other resistant mechanisms of individual strain.

Oral Diseases (2012) 18, 625–632 Non-exposed bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a newly reported complication arising from bisphosphonate therapy that presents with atypical symptoms and no apparent mucosal fenestration or exposure of necrotic bone. The clinical observation of the presence of necrotic bone underneath normal epithelial coverage was not conclusive for the diagnosis of BRONJ based on current guidelines established by the American Association of Oral and Maxillofacial Surgeons (AAOMS) and the American Society for Bone and Mineral Research (ASBMR), which specify the presence of clinically exposed necrotic bone for more than 8 weeks. Hence, the purpose of this review is to critically assess the current guidelines for diagnosis and management of BRONJ and propose a modified staging system and treatment guidelines to properly address the non-exposed variant of BRONJ lesions.

A recent paradigm shift in microbiology affects orthopaedic surgery and most other medical and dental disciplines because more than 65% of bacterial infections treated by clinicians in the developed world are now known to be caused by organisms growing in biofilms. These slime-enclosed communities of bacteria are inherently resistant to host defenses and to conventional antibacterial therapy, and these device-related and other chronic bacterial infections are unaffected by the vaccines and antibiotics that have virtually eliminated acute infections caused by planktonic (floating) bacteria. We examine the lessons that can be learned, within this biofilm paradigm, by the study of problems (e.g. non-culturability) shared by all biofilm infections and by the study of new therapeutic options aimed specifically at sessile bacteria in biofilms. Orthopaedic surgery has deduced some of the therapeutic strategies based on assiduous attention to patient outcomes, but much can still be learned by attention to modern research in related disciplines in medicine and dentistry. These perceptions will lead to practical improvements in the detection, management, and treatment of infections in orthopaedic surgery.

Microbial biofilms have been observed and described in bone specimens of patients with bisphosphonate (BP)-associated osteonecrosis of the jaw (BONJ) and investigators are more recently suggesting that this condition essentially represents an osteomyelitis of the jaw clinically, with greater susceptibility in some patients on BP therapy. This article explains the role of microbial biofilms in BONJ and also discusses associated factors in the disease pathogenesis, which include BP effects on bone remodeling, anti-angiogenesis, matrix necrosis, microcracks, soft tissue toxicity, and inflammation and wound healing. Recent findings suggest a key role for microbial biofilms in the pathogenesis of BONJ; this has important therapeutic implications because biofilm organisms represent a clinical target for prevention and treatment efforts aimed at reducing the significant morbidity and costs associated with this condition.

Of the approximately 8,400 children born each year in the US with cytomegalovirus (CMV)-induced birth defects, more than one third exhibit hypoplasia and hypocalcification of tooth enamel. Our prior studies indicated that CMV severely delayed, but did not completely interrupt, early mouse mandibular first molar morphogenesis in vitro. The aim of the present study was to examine the effects of CMV infection on progressive tooth differentiation and amelogenesis. Since initial CMV infection in human fetuses can occur at different developmental times, we varied the stage of initial viral infection (that is, Cap stage, Early Bell stage and Bell stage), as well as the duration of infection. CMV infection of embryonic mouse mandibular first molars in vitro induces tooth dysmorphogenesis and enamel defects in a developmental stage- and duration-dependent manner. Cap stage- and Early Bell stage-infected molars exhibit enamel agenesis and Bell stage-infected molars exhibit enamel hypoplasia. This viral-induced pathology is coincident with stage-dependent changes in Amelx, Enam and Dspp gene expression, distribution of amelogenin, enamelin and DSP proteins, cell proliferation localization and dedifferentiation of secretory ameloblasts. Importantly, our data indicate that specific levels of Amelx and Dspp gene expression define whether mouse CMV induces enamel agenesis or hypoplasia.

A novel coaxial tubular device capable of generating a 2.5 cm long pencil-like plasma plume in ambient atmosphere has recently been developed to disinfect root canal systems during endodontic treatment. Powered with short (≈100 ns), intense (6 kV) electric pulses at 1 kHz, the plasma dental probe is safe for operation, electromagnetic noise-free, with low power consumption (an average power of ≈1 W) and minimal heating of materials under treatment. It thus has the essential features required for oral and dental disinfection. In this communication, we present the design of the device and evidence that the plasma dental probe is effective for tooth surface disinfection. Scanning electron microscopy shows complete destruction of endodontic biofilms for a depth of 1 mm inside a root canal after plasma treatment for 5 min. Plasma emission spectroscopy identifies atomic oxygen as one of the likely active agents for the bactericidal effect.

Background Periodontitis is a classic example of biofilm-mediated diseases. Methods The authors reviewed selected publications in English-language peer-reviewed journals with respect to microbial biofilms, focusing on representative works that provided a historical to a contemporary perspective on periodontal oral biofilms in the larger context of biofilm microbiology. Results Developments in advanced microscopy and molecular microbiology have allowed scientists to examine and characterize microbial biofilm-mediated diseases, such as periodontitis, more accurately than in the past. Conclusions Periodontitis, like other biofilm infections, is refractory to antibiotic agents and host defenses because the causative microbes live in complex communities that persist despite challenges that range from targeted antibiotic agents to phagocytosis. Clinical Implications The regular delivery of nontargeted antibiofilm agents may be an effective strategy for treating biofilms, especially if these agents include oxidative agents that dissolve the biofilm matrix.

A new plasma dental probe (PDP), powered with 4-6-kV ~100-ns electric pulses at repetition rates of up to 2 kHz, generates a room-temperature > 2-cm-long ~2-mm-diameter plasma plume at ambient atmospheric pressure. The shape of the plasma plume depends on the gas flow rate and the pulse voltage. Growth of Bacillus atrophaeus on nutrient agar plates is completely inhibited by exposure to both He and He/(1%)O2 plasmas for 60 s. A 300-s treatment with the He/(1%)O2 plasma disinfected a human tooth root canal colonized with saliva-derived biofilms, demonstrating the potential of the PDP as a simple, safe, and effective tool or adjunct for the disinfection of root canals during endodontic therapy. He/(1%)O2 plasma is more effective than He alone for B. atrophaeus growth inhibition, and the emission spectrum of the He-O2 plasma supports the identification of atomic oxygen as the likely primary reactive chemical species contributing to bacterial inactivation.

Background Initial reports of osteonecrosis of the jaw (ONJ) secondary to bisphosphonate (BP) therapy indicated that patients receiving BPs orally were at a negligible risk of developing ONJ compared with patients receiving BPs intravenously. The authors conducted a study to address a preliminary finding that ONJ secondary to oral BP therapy with alendronate sodium in a patient population at the University of Southern California was more common than previously suggested. Methods The authors queried an electronic medical record system to determine the number of patients with a history of alendronate use and all patients receiving alendronate who also were receiving treatment for ONJ. Results The authors identified 208 patients with a history of alendronate use. They found that nine had active ONJ and were being treated in the school's clinics. These patients represented one in 23 of the patients receiving alendronate, or approximately 4 percent of the population. Conclusions This is the first large institutional study in the United States with respect to the epidemiology of ONJ and oral bisphosphonate use. Further studies along this line will help delineate more clearly the relationship between oral BP use and ONJ. Clinical Implications The findings from this study indicated that even short-term oral use of alendronate led to ONJ in a subset of patients after certain dental procedures were performed. These findings have important therapeutic and preventive implications.