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Peri-implantitis may result in the loss of dental implants. Cold atmospheric pressure plasma (CAP) was suggested to promote re-osseointegration, decrease antimicrobial burden, and support wound healing. However, the long-term risk assessment of CAP treatment in the oral cavity has not been addressed. Treatment with two different CAP devices was compared against UV radiation, carcinogen administration, and untreated conditions over 12 months. Histological analysis of 406 animals revealed that repeated CAP exposure did not foster non-invasive lesions or squamous cell carcinoma (SCCs). Carcinogen administration promoted non-invasive lesions and SCCs. Molecular analysis by a qPCR screening of 144 transcripts revealed distinct inflammatory profiles associated with each treatment regimen. Interestingly, CAP treatment of carcinogen-challenged mucosa did not promote but instead left unchanged or reduced the proportion of non-invasive lesions and SCC formation. In conclusion, repeated CAP exposure of murine oral mucosa was well tolerated, and carcinogenic effects did not occur, motivating CAP applications in patients for dental and implant treatments in the future.

Objectives Surgical masks are usually contaminated during dental treatment. So far it has not been investigated whether a surgical mask itself can be a source of microbial transmission. The aim of this study was therefore to investigate the microbiological contamination of surgical masks during dental treatment and the transfer of microorganisms from the mask to the hands. Materials and methods Five dental treatment modalities were studied: carious cavity preparation (P-caries, n = 10), tooth substance preparation (P-tooth, n = 10), trepanation and root canal treatment (P-endo, n = 10), supragingival ultrasonic application (US-supra, n = 10), and subgingival periodontal ultrasonic instrumentation (US-sub, n = 10). Bacterial contamination of mask and gloves worn during treatment was tested by imprinting on agar plates. Additionally, before masks were tested, their outer surface was touched with a new sterile glove. This glove was also imprinted on agar. Bacteria were identified by MALDI TOF mass spectrometry. Colony-forming units (CFU) were scored: score 0: 0 CFU, score 1: 2 CFU, score 2: > 102 CFU, score 3: dense microbial growth. Results All masks and all gloves used during treatment displayed bacterial contamination (sample scores 0/1/2/3: masks 0/46/3/1 and gloves 0/31/10/9). After touching the masks with new sterile gloves, microorganisms were recovered with the following contamination scores: P-caries: 4/6/0/0, P-tooth: 2/8/0/0: P-endo: 7/3/0/0, US-supra: 0/9/1/0, US-sub: 2/8/0/0. No statistically significant differences were detected between the treatment modalities. Streptococci spp. and Staphylococci spp. representing the oral and cutaneous flora dominated. Conclusions Surgical masks are contaminated after aerosol-producing dental treatment procedures. Used masks have a potential to be a source of bacterial contamination of the hands. Clinical relevance Dental staff should avoid touching the outer surface of masks with their hands to prevent transmission of pathogens. It is recommendable to change the mask after each treated patient followed by hand disinfection.

Background Microbial contamination of dental professionals’ facial protective equipment and skin from aerosols and droplets generated during dental treatment has not been studied in all aspects so far. Our aim was therefore to investigate and compare treatment-related bacterial contamination of the forehead skin and surgical mask of dental practitioners. Methods We analyzed samples from 67 consecutive aerosol-producing conservative-preventive dental treatments. Sterile nylon swabs were used to collect samples from the forehead skin before and after performing treatment. Contact samples were obtained from the used surgical face masks. Samples were cultivated on agar under aerobic and anaerobic conditions. Bacteria were classified by MALDI-TOF mass spectrometry. The frequency of detection of obligate and facultative oral bacteria, as well as an increase in bacterial abundance, were examined (bacterial scoring: 0: no growth on agar; 1: 2 colonies; 2: >102 colonies; 3: dense bacterial growth). Results Bacteria were detected in 95% of the skin swabs and 76% of mask samples. Median bacterial scores were 2 for the forehead skin samples before and after treatment, and 1 for samples obtained from masks. Obligate and facultative oral bacteria were more frequent (6% and 30%) in samples from forehead skin after treatment. Samples taken from the forehead skin after treatment showed increased scores for these bacteria (28%). Five percent of samples were positive for methicillin-sensitive Staphylococcus aureus (MSSA). Obligate anaerobes were present in 3% of samples. Conclusions Although exposed during treatment, the forehead skin was significantly less contaminated with obligate oral bacteria than expected based on the surgical face mask findings. Forehead skin samples showed an increase in bacteria in the after treatment, which can be attributed to aerosol-producing procedures. We hypothesize that the forehead’s physiological skin flora may offer some protection against contamination with other microorganisms.

Background Bacterial contamination of dental professionals’ facial skin and protective equipment from treatment-related aerosols and droplets are poorly studied. Methods This prospective study analyzed samples from 67 consecutive aerosol-producing dental treatments. Sterile nylon swabs served to collect samples from dental professionals’ foreheads before and after exposure. Contact samples were obtained from used surgical masks. Samples were incubated on agar under aerobic and anaerobic conditions. Bacteria were classified by MALDI-TOF mass spectrometry. We determined the frequencies of obligate and facultative oral bacteria and scored bacterial growth (0: none; 1: < 100 colonies; 2: >100 colonies; 3: dense). Results Bacteria were detected in 95% of skin-swab and 76% of mask samples. Median bacterial scores were 2 for forehead samples before and after treatment, and 1 for masks. Obligate and facultative oral bacteria were more frequent (6% and 30%) in samples from exposed forehead skin, which also showed increased bacterial scores (28%). 5% of samples contained methicillin-sensitive Staphylococcus aureus; 3% contained obligate anaerobes. Conclusion Exposed forehead skin was significantly less contaminated with obligate oral bacteria than expected based on surgical mask findings. Exposed forehead skin showed increased contamination attributable to aerosol-producing procedures. The forehead’s physiological skin microbiota may offer some protection against bacterial contamination.

BACKGROUND: Caries and periodontitis are highly prevalent worldwide. Because detailed data on these oral diseases were collected within the framework of the German National Cohort (GNC), associations between oral and systemic diseases and conditions can be investigated. OBJECTIVES: The study protocol for the oral examination was designed to ensure a comprehensive collection of dental findings by trained non-dental staff within a limited examination time. At the mid-term of the GNC baseline examination, a first quality evaluation was performed to check the plausibility of results and to propose measures to improve the data quality. MATERIALS AND METHODS: A dental interview, saliva sampling and oral diagnostics were conducted. As part of the level‑1 examination, the number of teeth and prostheses were recorded. As part of the level‑2 examination, detailed periodontal, cariological and functional aspects were examined. All examinations were conducted by trained non-dental personnel. Parameters were checked for plausibility and variable distributions were descriptively analysed. RESULTS: Analyses included data of 57,967 interview participants, 56,913 level‑1 participants and 6295 level‑2 participants. Percentages of missing values for individual clinical parameters assessed in level 1 and level 2 ranged between 0.02 and 3.9%. Results showed a plausible distribution of the data; rarely, implausible values were observed, e.g. for measurements of horizontal and vertical overbite (overjet and overbite). Intra-class correlation coefficients indicated differences in individual parameters between regional clusters, study centres and across different examiners. CONCLUSIONS: The results confirm the feasibility of the study protocol by non-dental personnel and its successful integration into the GNC’s overall assessment program. However, rigorous dental support of the study centres is required for quality management. HINTERGRUND:Karies und Parodontitis sind weltweit hoch prävalente Erkrankungen. Durch ihre Erfassung im Rahmen der NAKO Gesundheitsstudie können Assoziationen zwischen oralen und systemischen Erkrankungen untersucht werden. FRAGESTELLUNG: In einer ersten Qualitätsanalyse zur Halbzeit der NAKO-Basiserhebung wird die Plausibilität der zahnmedizinischen Ergebnisse überprüft. Es werden Maßnahmen zur Verbesserung der Datenqualität vorgeschlagen. MATERIAL UND METHODEN: Ein zahnmedizinisches Interview, eine Speichelprobengewinnung und eine Befunderhebung wurden durchgeführt. Im Rahmen der Level-1-Untersuchung wurden Zahn- und Prothesenanzahl erfasst. In der Level-2-Untersuchung wurden detaillierte parodontologische, kariologische und funktionelle Befunde erhoben. Alle Untersuchungen wurden von geschultem nichtzahnmedizinischen Personal durchgeführt. Es wurden Plausibilitätsprüfungen durchgeführt sowie Verteilungen deskriptiv dargestellt. ERGEBNISSE: In die Analysen gingen Daten von 57.967 Interviewteilnehmer*innen, 56.913 Level-1- und 6295 Level-2-Teilnehmer*innen ein. Der Anteil fehlender Werte lag für die einzelnen Parameter der Level-1- und Level-2-Untersuchungen zwischen 0,02 % und 3,9 %. Die Parameter zeigten eine plausible Verteilung; vereinzelt wurden unplausible Werte beobachtet, z. B. beim horizontalen und vertikalen Überbiss (Overjet und Overbite). Anhand der Intraklassenkorrelationskoeffizienten wurden für die einzelnen Parameter Unterschiede zwischen regionalen Clustern, den Studienzentren und verschiedenen Untersucher*innen nachgewiesen. DISKUSSION: Die bisherigen Ergebnisse bestätigten die Umsetzbarkeit des Studienprotokolls durch nichtzahnmedizinisches Personal und die erfolgreiche Integration in das Untersuchungsprogramm der NAKO Gesundheitsstudie. Die Studienzentren benötigen eine intensive zahnmedizinische Betreuung für das Qualitätsmanagement.

Cold atmospheric pressure plasma (CAP) has been investigated with promising results for peri-implant diseases treatment. However, prior to in-vivo applications of CAP sources in humans, short-term harmful mucosal damage or other unwanted side effects have to be reviewed. 180 male mice (B6C3F1) were divided into twelve treatment groups (n = 15). The right buccal cheek mucosa was treated with CAP. The first and second group each received continuous 10 sec irradiation with 2 different plasma sources (kINPen09, PS-MWM). The third group was treated with the kINPen09 for one minute. Control groups were treated with a corresponding dose of ultraviolet light for 8 seconds or 48 seconds and the other one was left untreated. The animals were weighed before and after treatment. The animals were sacrificed one day or one week after exposure. Stained tissue samples were histologically examined for tissue damage independently by two experienced pathologists. One day after CAP treatment histological analysis showed focal mucosal erosion with superficial ulceration and necrosis accompanied by a mild inflammatory reaction. One week after CAP treatment, the mucosal defects were completely re-epithelialized, associated with remnants of granulation tissue in the stroma irrespective of treatment duration. Furthermore, no cytological atypia was found and no severe weight loss occurred. The control groups did not show any alterations at all. CAP treatment led to a superficial mucosal damage that healed within few days. Nonetheless, further long-term experiments are necessary to exclude undesirable side effects after longer observation time. Particularly, potential carcinogenic effects must be ruled out prior to the application of CAP treatment in daily dental practice.

Plasma medicine is an innovative research field combining plasma physics, life science, and clinical medicine. It is mainly focused on the application cold atmospheric plasma (CAP) in therapeutic settings. Based on its ability to inactivate microorganisms but also to stimulate tissue regeneration, current medical applications are focused on the treatment of wounds and skin diseases. Since CAP is also able to inactivate cancer cells, its use in cancer therapy is expected to be the next field of clinical plasma application. Other promising applications are expected in oral medicine and ophthalmology. It is the current state of knowledge that biological CAP effects are mainly based on the action of reactive oxygen and nitrogen species supported by electrical fields and UV radiation. However, continuing basic research is not only essential to improve, optimize, and enlarge the spectrum of medical CAP applications and their safety, but it is also the basis for identification and definition of a single parameter or set of parameters to monitor and control plasma treatment and its effects. In the field of CAP plasma devices, research and application are currently dominated by two basic types: dielectric barrier discharges and plasma jets. Its individual adaptation to specific medical needs, including its combination with technical units for continuous and real-time monitoring of both plasma performance and the target that is treated, will lead to a new generation of CAP-based therapeutic systems.

Cold atmospheric plasmas for caries prophylaxis and for caries therapy are still subject of intensive biomedical basic research. From today’s perspective, plasma medicine provides promising potential in the field of cariology as an adjunctive measure for the disinfection of the dentine and for the improvement of the durability of composite fillings.

Balkenhol M, Rupf S, Laufersweiler I, Huber K, Hannig M. Failure analysis and survival rate of post and core restorations under cyclic loading. International Endodontic Journal, 44, 926–937, 2011. Abstract Aim To investigate in a laboratory setting the influence of (i) post material (ii) preparation design and (iii) luting agent on the survival probability of root filled teeth, restored with all-ceramic restorations. Methodology The crowns of 80 extracted single-rooted human teeth were removed, and root canal treatment was performed including canal filling with Gutta-percha without sealer (crown-down-pressureless technique). The root fillings were removed and the root canal enlarged with a reamer up to size 110. Prefabricated zirconia (CeraPost) or glass-fibre-reinforced posts (DentinPost) were luted using either Ketac Cem or Panavia F 2.0. A core build-up was applied (Clearfil Photocore), and the teeth were prepared with or without a 2-mm ferrule design (n = 10 per experimental group). The prepared teeth were scanned (Cerec 3D) and crowns fabricated. After luting of the crowns (Ketac Cem), teeth were subjected to thermocycling (×4000, 5–55 °C) and cyclic loading (1.5 million cycles, 90 N). After load cycling, the teeth were immersed in methyleneblue solution for 24 h and subsequently sectioned in three segments for a dye penetration test. Kaplan–Meyer analysis was performed to assess the survival probability followed by a Cox regression analysis (α = 5%). Results Teeth prepared using the ferrule design as well as the teeth with DentinPosts exhibited a significantly higher survival probability (P 0.05). Most common failure was debonding of posts (CeraPost) and post fracture (DentinPost). The majority of the teeth showed dye penetration after cyclic loading. Conclusions Post material and ferrule design were of paramount importance regarding the survival probability of the post and core restorations using pre-fabricated posts. DentinPosts showed superior results versus CeraPosts.

Summary Oral squamous cell carcinomas (OSCCs) often present as advanced tumours requiring aggressive local and regional therapy and result in significant functional impairment. The objective is to develop pre-symptomatic screening detection of OSCC by a brush biopsy method which is less invasive than the conventional biopsy for histology. Given the molecular heterogeneity of oral cancer, it is unlikely that even a panel of tumour markers would provide accurate diagnosis. Therefore, approaches such as the matrix-assisted-laser-desorption/ionisation-time-of-flight-mass-spectrometry (MALDI-TOF-MS) allow several biomarkers or peptide profile patterns to be simultaneously assessed. Brush biopsies from 27 patients with histology-proven OSCCs plus 40 biopsies from 10 healthy controls were collected. MALDI-TOF-MS profiling was performed and additional statistical analysis of the data was used to classify the disease status according to the biological behaviour of the lesion. For classification a support vector machine algorithm was trained using spectra of brush biopsy samples to distinguish healthy control patients from patients with histology-proven OSCC. MALDI-TOF-MS was able to distinguish between healthy patients and OSCC patients with a sensitivity of 100% and specificity of 93%. In summary, MALDI-TOF-MS in combination with sophisticated bioinformatic methods can distinguish OSCC patients from non-cancer controls with excellent sensitivity and specificity. Further improvement and validation of this approach is necessary to determine its feasibility to assist the pre-symptomatic detection of head and neck cancer screening in routine daily practice.

The purpose of this study was to conduct an in vitro and short-term clinical and microbiological evaluation of a linear oscillating device for scaling and root planing (SRP). A comparison was made between conventional ultrasonic scaling (US) and hand scaling (HS) with and without chlorhexidine.In vitro, SRP was carried out on human teeth with calculus. Roots and cross-sections thereof were microscopically examined for the efficacy of calculus removal, hard tissue loss, and surface smoothness. In vivo, 11 patients with chronic periodontitis and single-rooted teeth in all quadrants with probing depths ofor =5 mm were selected. One quadrant was treated with linear oscillation and compared to US with chlorhexidine irrigation in the contralateral site. The other arch was treated with HS and compared to HS followed by laser disinfection. One hundred twenty teeth were assessed for clinical attachment level, probing depth, bleeding on probing, and suppuration at baseline and 7, 28, 90, and 180 days. Microbiologically, total numbers of bacteria and six specific periodontal pathogens were determined by quantitative polymerase chain reaction prior to and 1 and 28 days after SRP. Clinical and microbiological data were analyzed statistically with respect to the SRP method, patient specificity, and time effect.In vitro, linear oscillation preserved more root tissues but left more calculus (P0.05). Significant improvements of all clinical and microbiological parameters were observed for all groups. However, 21 out of 24 tests demonstrated that the clinical microbiological correlations between linear oscillation and control groups did not differ (P0.05).Linear oscillation scaling was clinically acceptable and microbiologically comparable to the control groups despite microscopic remnants of calculus observed in vitro.

Summary Objectives Intact cell peptidome profiling (ICPP) with MALDI-ToF Mass Spectrometry holds promise as a non-invasive method to detect head and neck squamous cell carcinoma (HNSCC) objectively, which may significantly improve the early diagnosis of oral cancer. The present study was designed to discriminate between tumour samples and non-cancer controls (healthy mucosa and oral lesions) by analysing complete spectral patterns of intact cells using MALDI-ToF MS. Materials and methods In the first step, a database consisting of 26 patients suffering from HNSCC was established by taking brush biopsy samples of the diseased area and of the healthy buccal mucosa of the respective contralateral area. After performing MALDI-ToF MS on these samples, classification analysis was used as the basis for further classification of an additional 26 blinded samples including HNSCC, oral lesions and healthy mucosa. Results By analysing spectral patterns of the blinded samples, all cancerous lesions were defined accurately. One incorrect evaluation (false positive) occurred in the lesion cohort, leading to a sensitivity of 100%, a specificity of 93% and an overall accuracy of 96.5%. Conclusion ICPP using MALDI-ToF MS is able to distinguish between healthy and cancerous mucosa and between oral lesions and oral cancer with excellent sensitivity and specificity, which may lead to more accurate early diagnosis of HNSCC.

Aim: This was to study the longitudinal assessment of caries activity of Streptococcus sobrinus (SS) positive children during their mixed dentition. Methods: The occurrence of mutans streptococci (MS) in plaque and saliva was determined in a representative sample of 55 children aged 8 to 12 years over a period of 4 years. A total of 708 bacterial strains was isolated which were identified as MS or SS. Caries activity (ΔD1−4MFS) as well as plaque and gingival inflammation were recorded. Results: During the period of observation 52 of the 55 children harboured MS; 12 of these children were SS positive. SS was not permanently detectable and 3 of the children were MS and SS negative. SS was not found without the presence of MS. Children that were infected with both SS and MS showed a slightly higher increase in caries compared with children that were infected exclusively by MS (ΔD1,2MFS 6.2 vs. 3.0 and ΔD3,4MFS 5.3 vs. 3.8) over the period of 4 years. An SS infection accelerated the increase of ΔD3,4MFS significantly by a factor of 4 one year after its detection, whereas the ΔD1,2MFS was 3 times as high during the period of infection. Conclusion: The findings suggest that an SS infection represents an important additional risk factor for dental caries due to its obvious aggravating of caries activity.