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Structured examination and treatment are essential in medicine. For dental students, a structured approach to the assessment of oral mucosal lesions is missing thus far. To validate an approach, a structured questionnaire was compared with the habitually used free description of oral lesions (white lesions, ulcers, hyperplasia). Thirty-three dental students were divided into two groups (Group 1 (n = 17) used the free description; Group 2 (n = 16) used a guided questionnaire) to characterize mucosal lesions in patients and make a tentative diagnosis. Although no difference was found between the groups regarding the suspected diagnosis or the histopathological findings, there was a significant advantage of the structured questionnaire in all aspects of the description compared to the free description (p = 0.000018). Thus, a structured description is an important aspect in the evaluation of oral mucosal changes, and a guided questionnaire should be implemented in the study of dentistry.
Gas plasma is an approved technology that generates a plethora of reactive oxygen species, which are actively applied for chronic wound healing. Its particular antimicrobial action has spurred interest in other medical fields, such as periodontitis in dentistry. Recent work has indicated the possibility of performing gas plasma-mediated biofilm removal on teeth. Teeth frequently contain restoration materials for filling cavities, e.g., resin-based composites. However, it is unknown if such materials are altered upon gas plasma exposure. To this end, we generated a new in-house workflow for three commonly used resin-based composites following gas plasma treatment and incubated the material with human HaCaT keratinocytes in vitro. Cytotoxicity was investigated by metabolic activity analysis, flow cytometry, and quantitative high-content fluorescence imaging. The inflammatory consequences were assessed using quantitative analysis of 13 different chemokines and cytokines in the culture supernatants. Hydrogen peroxide served as the control condition. A modest but significant cytotoxic effect was observed in the metabolic activity and viability after plasma treatment for all three composites. This was only partially treatment time-dependent and the composites alone affected the cells to some extent, as evident by differential secretion profiles of VEGF, for example. Gas plasma composite modification markedly elevated the secretion of IL6, IL8, IL18, and CCL2, with the latter showing the highest correlation with treatment time (Pearson’s r > 0.95). Cell culture media incubated with gas plasma-treated composite chips and added to cells thereafter could not replicate the effects, pointing to the potential that surface modifications elicited the findings. In conclusion, our data suggest that gas plasma treatment modifies composite material surfaces to a certain extent, leading to measurable but overall modest biological effects.
Due to a variety of plasma sources in terms of type of discharge, energy yield, working gas or geometric factors, it is recommended to standardize the study protocol by choosing a plasma source and easy access to rugged tumor surfaces as demonstrated by the CAP-plasma-jet. The intention of the trial shall be to optimize the plasma jet for tumor site capability and operating room implementation.
It makes sense to start clinical trials in plasma medicine with the treatment of head and neck squamous cell carcinoma patients of infected wounds and ulcerations.
CAP is able to reduce contamination of cancer ulcerations and the typical fetid odor that often accompanies head and neck cancer patients. The intention of the trial shall be to evaluate the efficiency of decontamination in head and neck cancer ulcerations in terms of pathogenic species, amount of reduction and reliability.
Standardize study protocol:
Phase I, clinical explorative single-arm, randomized, open, multicenter
Primary objective
Reduction of microbial burden of cancer ulcerations by application of CAP
Secondary objective:
Reduction of tumor following local CAP application
Inclusion:
20 Patients suffering from locally advanced oral cavity carcinoma with open tumor surfaces, treated with palliative intention and no more curative treatment options
Exclusion:
No wish for treatment, no compliance and understanding the protocol of the clinical study
Efficacy:
reduction of microbial burden; Documentation of visible changes by photography; Pathohistological and biochemical examination of specimen, taken from the tumor area and control areas
Procedure:
Plasma is applied for 1 minute per cm², spot area of 3 mm diameter distance between nozzle and tumor surface of 14 mm. 3 times/week with a break of 1 week followed by a repeated cycle for another week.
Conclusion:
The most important intention of the trial from the clinician’s point of view shall be to make CAP-treatment an effective and well-accepted addition to standard cancer therapy based upon EBM at least in palliative medicine.
(1) Background: The aim of this study was to systematically compare TEM sections of mineralized human enamel and dentine prepared by focused ion beam (in situ lift-out) technique and ultramicrotomy through a combination of microscopic examination methods (scanning electron microscopy and transmission electron microscopy). In contrast with published studies, we compared the TEM preparation methods using the same specimen blocks as those for the ultramicrotomy and FIB technique. (2) Methods: A further evaluation of TEM sample preparation was obtained by confocal laser scanning microscopy and atomic force microscopy. In addition, ultramicrotome- and focused ion beam-induced artefacts are illustrated. (3) Results: The FIB technique exposed a major difference between non-decalcified enamel and dentine concerning the ultrastructural morphology compared to ultramicrotome-prepared sections. We found that ultramicrotomy was useful for cutting mineralized dentine, with the possibility of mechanical artefacts, but offers limited options for the preparation of mineralized enamel. FIB preparation produced high-quality TEM sections, showing the anisotropic ultrastructural morphology in detail, with minor structural artefacts. Our results show that the solution of artificial saliva and glutardialdehyde (2.5% by volume) is a very suitable fixative for human mineralized tissue. (4) Conclusions: The protocol that we developed has strong potential for the preparation of mineralized biomaterials for TEM imaging and analysis.
Reactive species generated by medical gas plasma technology can be enriched in liquids for use in oncology targeting disseminated malignancies, such as metastatic colorectal cancer. Notwithstanding, reactive species quantities depend on the treatment mode, and we recently showed gas plasma exposure in conductive modes to be superior for cancer tissue treatment. However, evidence is lacking that such a conductive mode also equips gas plasma-treated liquids to confer augmented intraperitoneal anticancer activity. To this end, employing atmospheric pressure argon plasma jet kINPen-treated Ringer’s lactate (oxRilac) in a CT26-model of colorectal peritoneal carcinomatosis, we tested repeated intraabdominal injection of such remotely or conductively oxidized liquid for antitumor control and immunomodulation. Enhanced reactive species formation in conductive mode correlated with reduced tumor burden in vivo, emphasizing the advantage of conduction over the free mode for plasma-conditioned liquids. Interestingly, the infiltration of lymphocytes into the tumors was equally enhanced by both treatments. However, significantly lower levels of interleukin (IL)4 and IL13 and increased levels of IL2 argue for a shift in intratumoral T-helper cell subpopulations correlating with disease control. In conclusion, our data argue for using conductively over remotely prepared plasma-treated liquids for anticancer treatment.
Decreased inflammatory profile in oral leukoplakia tissue exposed to cold physical plasma ex vivo
(2023)
Background
Oral leukoplakia (OL) is an unfavorable oral disease often resistant to therapy. To this end, cold physical plasma technology was explored as a novel therapeutic agent in an experimental setup.
Methods
Biopsies with a diameter of 3 mm were obtained from non-diseased and OL tissues. Subsequently, cold atmospheric pressure plasma (CAP) exposure was performed ex vivo in the laboratory. After 20 h of incubation, biopsies were cryo-conserved, and tissue sections were quantified for lymphocyte infiltrates, discriminating between naïve and memory cytotoxic and T-helper cells. In addition, the secretion pattern related to inflammation was investigated in the tissue culture supernatants by quantifying 10 chemokines and cytokines.
Results
In CAP-treated OL tissue, significantly decreased overall lymphocyte numbers were observed. In addition, reduced levels were observed when discriminating for the T-cell subpopulations but did not reach statistical significance. Moreover, CAP treatment significantly reduced levels of C-X-C motif chemokine 10 (CXCL10) and granulocyte-macrophage colony-stimulating factor in the OL biopsies' supernatants. In idiopathically inflamed tissues, ex vivo CAP exposure reduced T-cells and CXCL10 as well but also led to markedly increased interleukin-1β secretion.
Conclusion
Our findings suggest CAP to have immuno-modulatory properties, which could be of therapeutic significance in the therapy of OL. Future studies should investigate the efficacy of CAP therapy in vivo in a larger cohort.
Objectives: Performing proper toothbrushing is a complicated process for children. Therefore, the aim of this study was to investigate the effect of a smartphone app for improving manual toothbrushing via a gravitation sensor. Methods: In this prospective, controlled, single-blinded, randomized clinical trial, 49 children (mean age 5.1 ± 0.6 years, 27 female) were randomly assigned to test (n = 26) and control (n = 23) groups. All children were provided with manual toothbrushes with an integrated gravitation sensor and they received oral health instructions. Only the children of the test group got an additional smartphone app to visualize and reward proper brushing in form and time. At baseline and recalls after 6 and 12 weeks, plaque and gingival indices (QHI, PBI) were recorded for analysis between the two groups. Results: At baseline, there were no significant differences between the test and control group regarding plaque and gingival indices (QHI: 2.36 ± 0.7 and 2.42 ± 0.8; p = 0.94; PBI: 0.42 ± 0.2 and 0.47 ± 0.3; p = 0.59). At the 6- and 12-week recalls, the test group showed statistically significantly better oral health indices than the controls (6-week recall, QHI: 0.8 ±0.5 and 1.88 ± 0.9; p < 0.001; PBI: 0.08 ± 0.1 and 0.26 ± 0.2; p < 0.001; 12-week recall, QHI: 0.44 ± 0.5 and 1.49 ± 0.7; p < 0.001; PBI: 0.05 ± 0.18 and 0.21 ± 0.1; p < 0.001). Conclusion: The results highlight the enormous possibilities of a toothbrushing application via the smartphone, at least for medium-term oral hygiene improvement in preschool children and even after excluding the app. The long-term effect should also be investigated to exclude the expected novelty effect.
Introduction
Medical gas plasma therapy has been successfully applied to several types of cancer in preclinical models. First palliative tumor patients suffering from advanced head and neck cancer benefited from this novel therapeutic modality. The gas plasma-induced biological effects of reactive oxygen and nitrogen species (ROS/RNS) generated in the plasma gas phase result in oxidation-induced lethal damage to tumor cells.
Objectives
This study aimed to verify these anti-tumor effects of gas plasma exposure on urinary bladder cancer.
Methods
2D cell culture models, 3D tumor spheroids, 3D vascularized tumors grown on the chicken chorion-allantois-membrane (CAM) in ovo, and patient-derived primary cancer tissue gas plasma-treated ex vivo were used.
Results
Gas plasma treatment led to oxidation, growth retardation, motility inhibition, and cell death in 2D and 3D tumor models. A marked decline in tumor growth was also observed in the tumors grown in ovo. In addition, results of gas plasma treatment on primary urothelial carcinoma tissues ex vivo highlighted the selective tumor-toxic effects as non-malignant tissue exposed to gas plasma was less affected. Whole-transcriptome gene expression analysis revealed downregulation of tumor-promoting fibroblast growth factor receptor 3 (FGFR3) accompanied by upregulation of apoptosis-inducing factor 2 (AIFm2), which plays a central role in caspase-independent cell death signaling.
Conclusion
Gas plasma treatment induced cytotoxicity in patient-derived cancer tissue and slowed tumor growth in an organoid model of urinary bladder carcinoma, along with less severe effects in non-malignant tissues. Studies on the potential clinical benefits of this local and safe ROS therapy are awaited.
Molecular Mechanisms of the Efficacy of Cold Atmospheric Pressure Plasma (CAP) in Cancer Treatment
(2020)
Reactive oxygen species (ROS) have been subject of increasing interest in the pathophysiology and therapy of cancers in recent years. In skin cancer, ROS are involved in UV-induced tumorigenesis and its targeted treatment via, e.g., photodynamic therapy. Another recent technology for topical ROS generation is cold physical plasma, a partially ionized gas expelling dozens of reactive species onto its treatment target. Gas plasma technology is accredited for its wound-healing abilities in Europe, and current clinical evidence suggests that it may have beneficial effects against actinic keratosis. Since the concept of hormesis dictates that low ROS levels perform signaling functions, while high ROS levels cause damage, we investigated herein the antitumor activity of gas plasma in non-melanoma skin cancer. In vitro, gas plasma exposure diminished the metabolic activity, preferentially in squamous cell carcinoma cell (SCC) lines compared to non-malignant HaCaT cells. In patient-derived basal cell carcinoma (BCC) and SCC samples treated with gas plasma ex vivo, increased apoptosis was found in both cancer types. Moreover, the immunomodulatory actions of gas plasma treatment were found affecting, e.g., the expression of CD86 and the number of regulatory T-cells. The supernatants of these ex vivo cultured tumors were quantitatively screened for cytokines, chemokines, and growth factors, identifying CCL5 and GM-CSF, molecules associated with skin cancer metastasis, to be markedly decreased. These findings suggest gas plasma treatment to be an interesting future technology for non-melanoma skin cancer topical therapy.
Plasma medical oncology: Immunological interpretation in head and neck squamous cell carcinoma
(2020)
Over the past several years, various important articles focusing on cancer therapy
approaches in head and neck squamous cell carcinomas (HNSCCs) using cold
atmospheric plasma (CAP) have been published (SEMMLER et al. 2020 [53],
METELMANN et al. 2018 [44], KEIDAR et al. 2011 [33]). This doctoral thesis presents
selected results from a prospective observational clinical study in CAP therapy of
palliative HNSCC patients, carried out at the Department of Oral and Maxillofacial
Surgery/Plastic Surgery of the Greifswald University Medicine. For oral and
maxillofacial surgeons, ulcerated surfaces of locally advanced head and neck squamous
cell carcinomas (UICC IV) offer a challenging treatment assignment with microbial
contamination and tumour progression. The clinical attempt appears to eradicate
microbial contamination and to initiate tumour regression. This doctoral thesis will
describe the processes of human tumour biology and tumour immunology in HNSCCs
and the extent of present knowledge concerning plasma medical oncology as an
anticancer modality. In the introduction of the doctoral thesis clinical results of plasma
therapy in locally advanced HNSCCs (UICC IV) are set out. This mainly includes the
investigation of a therapeutic concept, the treatment phases, the tumour size development
and the morphological changes of the infected tumour surface following cold atmospheric
plasma therapy. In the main part, a detailed immunological interpretation is proposed on
the basis of present preclinical and clinical immunological knowledge. Finally,
unexplored questions in plasma medical oncology are highlighted. This is highly
significant for future plasma research and clinical anticancer therapy.
Objectives
During the corona pandemic, dental practices temporarily closed their doors to patients except for emergency treatments. Due to the daily occupational exposure, the risk of SARS-CoV-2 transmission among dentists and their team is presumed to be higher than that in the general population. This study examined this issue among dental teams across Germany.
Materials and methods
In total, 2784 participants provided usable questionnaires and dry blood samples. Dry blood samples were used to detect IgG antibodies against SARS-CoV-2. The questionnaires were analyzed to investigate demographic data and working conditions during the pandemic. Multivariable logistic mixed-effects models were applied.
Results
We observed 146 participants with positive SARS-CoV-2 IgG antibodies (5.2%) and 30 subjects with a borderline finding (1.1%). Seventy-four out of the 146 participants with SARS-CoV-2 IgG antibodies did not report a positive SARS-CoV-2 PCR test (50.7%), while 27 participants without SARS-CoV-2 IgG antibodies reported a positive SARS-CoV-2 PCR test (1.1%). Combining the laboratory and self-reported information, the number of participants with a SARS-CoV-2 infection was 179 (6.5%). Though after adjustment for region, mixed-effects models indicated associations of use of rubber dams (OR 1.65; 95% CI: 1.01–2.72) and the number of protective measures (OR 1.16; 95% CI: 1.01–1.34) with increased risk for positive SARS-CoV-2 status, none of those variables was significantly associated with a SARS-CoV-2 status in fully adjusted models.
Conclusions
The risk of SARS-CoV-2 transmission was not higher among the dental team compared to the general population.
Clinical relevance.
Following hygienic regulations and infection control measures ensures the safety of the dental team and their patients.
S2k guidelines for the therapy of pathological scars (hypertrophic scars and keloids) – Update 2020
(2020)
The Study of Health in Pomerania (SHIP), a population-based study from a rural state in northeastern Germany with a relatively poor life expectancy, supplemented its comprehensive examination program in 2008 with whole-body MR imaging at 1.5 T (SHIP-MR). We reviewed more than 100 publications that used the SHIP-MR data and analyzed which sequences already produced fruitful scientific outputs and which manuscripts have been referenced frequently. Upon reviewing the publications about imaging sequences, those that used T1-weighted structured imaging of the brain and a gradient-echo sequence for R2* mapping obtained the highest scientific output; regarding specific body parts examined, most scientific publications focused on MR sequences involving the brain and the (upper) abdomen. We conclude that population-based MR imaging in cohort studies should define more precise goals when allocating imaging time. In addition, quality control measures might include recording the number and impact of published work, preferably on a bi-annual basis and starting 2 years after initiation of the study. Structured teaching courses may enhance the desired output in areas that appear underrepresented.