DZZ International, 06/2021

The current S2k-Guideline of the DEGRO (German Society for Radiation Oncology) provides a "should" recommendation for gonarthritis and a "can" recommendation for other arthritides. Thus, according to the guideline's recommendations, there is also the possibility to employ irradiation in the treatment of osteoarthritis or degenerative and/or inflammatory arthropathies of the TMJ. Keywords: activated osteoarthritis, degenerative arthropathy, radiotherapy, symptomatic inflammatory arthropahy, temporomandibular joint, treatment option

Contribution to the widespread problem of not necessarily serious scientific journals that offer the possibility of (online) publication, but let the authors pay quite dearly for this despite the limited coverage. Keywords: EbM Bits, medical databases, online journals, publication invitations

In the update of the S3 guideline "All-ceramic single crowns and fixed dental prostheses" (AWMF Reg. No. 083-012) published in June 2021, new scientific evidence was incorporated into the guideline first published in 2014. The guideline established a broadly consented, evidence-based framework within which the use of tooth-supported all-ceramic restorations offers comparable long-term clinical outcomes to metal-based crowns and fixed dental prostheses (FDPs). In the updated version (version 2.0), all chapters have been reviewed with regard to new research findings, backgrounds have been newly discussed, and numerous recommendations have been updated with regard to indications and localization. In the process, the recommendation grading of individual materials was adjusted on the basis of new literature. Recommendations on materials that are no longer on the market (alumina ceramics) were removed and recommendations on new materials and applications were added (zirconium oxide ceramics [3Y-TZP] monolithic; zirconium oxide ceramics [4Y-, 5Y-TZP and combinations with these]; resin-matrix ceramics; lithium silicate/phosphate glass-ceramics). Recommendations on endocrowns were also made for the first time. In addition, the questions regarding the treatment of bruxism patients with all-ceramic restorations as well as material-specific manufacturing recommendations were re-evaluated. The main recommendations are listed in this article, the key innovations are emphasized, and the considerations of the guideline group in arriving at the recommendations are summarized. All recommendations as well as complete references can be found in the long version of the German S3 guideline. Keywords: all-ceramics, crowns, fixed dental prostheses, guideline, prosthodontics, restorative materials, survival rates

Introduction: Glass-ceramic single-tooth restorations count among the standard treatments in dental practice at present owing to their good esthetics, biocompatibility and survival rates. The aim of this study was to investigate the occurrence of various long-term complications based on data collected from a general dental practice. Material and methods: A retrospective analysis of 1132 posterior single-tooth restorations made of Empress 2 and IPS e.max ceramic from 251 patients was performed. The restorations were placed between 2000 and 2015 by a single dental practitioner in a private general dental practice. The minimum observation period was 2 years. The patient records were examined for the following complications: fracture, root canal treatment, periodontal complications, occlusal adjustment procedures to correct occlusal interferences, postoperative hypersensitivity, secondary caries and decementation. The statistical analysis was based on the ceramic used (Empress 2 and IPS e.max) and the type of restoration (inlay, partial crown, or crown). Results: Twelve of the 769 Empress 2 and 3 of the 363 IPS e.max restorations failed due to bulk fracture. There was no significant difference between the materials (p = 0.411). Crowns displayed a significantly higher fracture rate compared to inlays or partial crowns (p = 0.02 and p = 0.04), irrespective of material. Empress 2 restorations showed a significantly higher incidence (3.6 %) of premature occlusal contacts requiring adjustment compared to IPS e.max restorations (1.4 %) (p = 0.037). No correlation between occlusal adjustment procedures and fracture was observed (p = 0.426). Empress 2 crowns had a significantly higher probability of decementation (p 0.001) compared to Empress 2 inlays or partial crowns. Teeth with IPS e.max restorations exhibited significantly more postoperative hypersensitivitity (p 0.001) and required root canal treatment significantly more frequently (p = 0.041) than teeth with Empress 2 restorations. Periodontal complications occurred significantly more often in teeth with IPS e.max crowns than in teeth with IPS e.max inlays or partial crowns (p = 0.005). The incidence of secondary carious lesions was not significantly higher neither with respect to material nor type of restoration. Conclusion: Both glass-ceramic materials are suitable for everyday use in dentistry; IPS e.max and Empress 2 restorations demonstrated good long-term clinical results and an acceptable amount of complications. The most common complications were postoperative hypersensitivity, fractures and peri-odontal complications. The number of complications was higher for crowns than for inlays or partial crowns. Keywords: complications, Empress 2, fracture rate, glass-ceramic, IPS e. max, long-term performance, retrospective, single-tooth restorations

Introduction: Depression is a leading cause of illness-related disability worldwide. An initial peak of illness is recorded in the young adult years. Among epidemiologic studies of young people, studies of students are primarily available. The mental health of dental students has received little research attention. Many students subjectively report mental health complaints, while studies on this topic are scarce nationally and internationally. This study investigates the mental health of dental students at a medium-sized German university. Methods: A sample of n = 153 dental students completed the Beck Depression Inventory-II to assess depressive symptoms, the NEO Five-Factor Inventory to assess the personality trait neuroticism, and a self-description and study questionnaire that included 8 risk factors, 5 study-related stress factors, and 8 resilience factors described in literature. Results: 41,8 % of the students showed mild (18,3 %), moderate (17,0 %), or severe (6,5 %) depressive symptoms. 5 potential risk factors, 4 potential stress factors and 5 potential resilience factors were identified, which also revealed a cumulative effect: The more risk and stress factors the students indicated, the more depressive symptoms they showed. The opposite was true for the resilience factors. Discussion: The prevalence of depressive symptoms in dental students exceeds that of both the general population and previous national and international studies of depressive symptoms in students. Neuroticism and the use of drugs and medications are potential risk factors, and excessive demands and pressure to perform are study-related stress factors. Emotional support and satisfaction with studies have a protective effect against depressive symptoms. Conclusion: The results are of great significance not only because of the current psychological strain on dental students but also regarding their role in the health care system. Students should be informed and sensitized regarding this issue. Specific education on depression is useful to destigmatize the issue and raise awareness of the condition. University programs can also contribute to an early recognition and prevention of depressive symptoms to protect the mental health of potential future dentists. Keywords: dentistry students, depression, depressive symptoms, mental health, prevalence, prevention, resilience factors, risk factors

Introduction: The aim is to compare different methods for the removal of calcium hydroxide (Ca(OH)2) from root canals. Material and methods: 160 extracted human teeth were divided into 2 groups. In group 1 (n = 80), all root canals were prepared with hand instruments to ISO size 40 and in group 2 (n = 80) by rotary nickel-titanium files (Mtwo) to size 04/40. After rinsing, all root canals were filled with Ca(OH)2 and the access cavity was temporized. All teeth were stored for 7 d at 37 °C and 100 % humidity. After storage, in half of the specimens of both groups (n = 40) root canal irrigation without previous instrumentation was performed. In the other half (n = 40) root canals were instrumented to working length with Hedstrom file ISO size 45. All specimens were divided in subgroups (n = 10) and rinsed with 5 ml of NaCl-solution 0.9 %, CHX 2 %, and NaOCl 2.5 % with or without ultrasonic activation, respectively. By scanning electron microscope evaluation the cleanliness of the root canal walls was scored from 1 (no Ca(OH)2 visible) to 5 (pronounced layer of Ca(OH)2). The data obtained were statistically evaluated by Kruskal-Wallis-test (p 0.05). Results: Ultrasonic-activated NaOCl removed significantly more Ca(OH)2 than all other solutions or methods (p 0.05). The instrument taper (hand instruments 2 % or NiTi files 4 %) as well as instrumentation before rinsing, had no significant influence (p > 0.05). For all rinsing solutions tested, the result within the respective group was independent of the localization in the root canal (p > 0.05). Conclusion: Only passive ultrasonic activation was able to remove Ca(OH)2 from the root canal sufficiently. Neither the taper of the instruments used nor instrumentation before rinsing had an significant influence on the removability of Ca(OH)2. Keywords: calcium hydroxide, instrument taper, passive ultrasonic irrigation (PUI), root canal dressing, root canal irrigation

Introduction: An evidence-based, balanced discussion of the facts regarding the reduction of infection risk during the SARS-CoV-2 pandemic by aerosol-controlling measures in dental practice has not yet been fully conducted. Therefore, the current state of knowledge on spray mist and aerosol control in dental offices will be reported in order to present conclusions on risk reduction of aerogen-transmitted infectious diseases in the dental practices. Methods: Results of studies directly related to spray mist and aerosol control in a dental office, as well as recommendations from publications including national position statements and guidelines for dentistry, are discussed in a narrative format. Results: Decision-making at the onset of the SARS-CoV-2 pandemic was hampered by the limited evidence base, but could be improved as the pandemic duration progressed by publishing more studies about spray mist and indoor aerosol control. Study results on the routine use of dental suction systems (intraoral) can be used to specify limits to their effectiveness in aerosol reduction. Similarly, findings on ubiquitously available natural room ventilation shows very high air exchange per hour (ACH) of up to 40 with continuous cross-ventilation under optimal room geometry with opposing windows, whereas only a limited additional effect can be expected for decentralized mobile air cleaning (DMAC) devices in reducing smaller aerosol particles in the treatment room. Discussion: For optimized infection protection in dentistry, in addition to natural room ventilation and compliance with all known hygiene guidelines, the use of intraoral suction (high-volume evacuator (HVE) with a suction volume > 250 l/min) using a sufficiently large suction cannula (opening ≥ 10 mm), positioned close to the aerosol-generating treatment field, is mandatory. From a clinical point of view, supplementary DMAC devices provide a negligible additional reduction effect during aerosol-generating activities. Room air exchange by natural room ventilation in combination with HVE systems shows a high efficiency and continues to be the standard procedure in dental practices. Future studies must clarify whether DMAC devices with ACH ≥ 6 can be a supplement in exceptional situations with a high risk of infection, for example, when no intraoral suction is used or protective/hygiene measures can only be observed to a limited extent. Conclusion: Established hygiene concepts and protective measures, including room ventilation with fresh air, have proven to be sufficiently effective in dental practice even during the SARS-CoV-2 pandemic. Keywords: SARSCoV-2, aerogene-transmitted infectious diseases, aerosol, guidelines