Eligibility and efficacy of a CPC- and CHX-based antiviral mouthwash for the elimination of SARS-CoV-2 from the saliva: A randomized, double-blind, controlled clinical trial.

AIM: This study aimed at investigating the efficacy of a 0.05% cetylpyridinium chloride-0.05% chlorhexidine (CPC-CHX) mouthwash in reducing viral load in the saliva as compared with sterile water. MATERIALS AND METHODS: Forty SARS-CoV-2 positive patients were asked to dispense 4 mL of saliva. Half the patients rinsed for 60 s with 15 mL CPC-CHX, and the remaining patients rinsed with sterile water (control). Four millilitres of saliva were collected after 15, 30 and 60 min after rinsing. Quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) specific for SARS-CoV-2 nucleocapsid protein were performed. For ELISA, the intact (representing the active virus) to total virus load (I/T) was calculated. RESULTS: SARS-CoV-2 copy numbers/mL from RT-qPCR tended to decrease in the control group, whereas in the CPC-CHX group, an increase was observed after T30. However, mixed linear model analysis revealed no statistical differences between groups (p = .124), time points (p = .616) and vaccinated or non-vaccinated patients (p = .953). Similarly, no impact of group (p = .880), time points (p = .306) and vaccination (p = .711) was observed for I/T ratio values. CONCLUSIONS: Within the limitation of this study, there was no evidence that the intervention reduced salivary SARS-CoV-2 viral load during the course of 60 min. Therefore, commonly used pre-procedural rinsing might not be clinically relevant.

Patterns of antibiotic prescription in implant dentistry and antibiotic resistance awareness among European dentists: A questionnaire-based study.

OBJECTIVES: Antimicrobial resistance is an alarming global public health concern, threatening the effective treatment of common infections. This phenomenon is driven by the improper prescription of antibiotics. This study aimed to elucidate the patterns of antibiotic prescription in implant dentistry among European dentists and their awareness of antibiotic resistance. MATERIALS AND METHODS: An anonymous online validated questionnaire was distributed via e-mail to 6431 recipients through the European Association for Osseointegration. It comprised of 17 structured questions investigating demographic variables, working environment, clinical experience, attitude towards antibiotic prescription in particular in relation to implant dentistry and COVID-19 pandemic, and awareness of antibiotic resistance. Data were collected from April to May 2023. RESULTS: 281 dentists from 33 European countries completed the survey. Almost 80% affirmed to routinely prescribe antibiotics as prophylaxis as well as after dental implant placement, especially in medically compromised patients or in cases of bone grafting. Amoxicillin, alone (61%) or in combination with clavulanic acid (56%), was the most common antibiotic of choice. Awareness of penicillin resistance among respondents was high. For peri-implantitis treatment, more than half reported the use of systemic antibiotics. The large majority (95%) did not prescribe more antibiotics since the beginning of COVID-19 pandemic. Less than 40% declared to follow national guidelines for antibiotic prescription. CONCLUSION: This survey revealed a high prescription rate of antibiotics in implant dentistry, despite the awareness about antibiotic resistance among the respondents. The development and adherence to European guidelines has been identified as a potential strategy for improving antimicrobial stewardship.

SARS-CoV-2 inactivation in laboratory animal tissues with 4% formaldehyde or 5% glutaraldehyde for transfer to biosafety level 1 laboratories.

The SARS-CoV-2 pandemic required the immediate need to transfer inactivated tissue from biosafety level (BSL)-3 to BSL-1 areas to enable downstream analytical methods. No validated SARS-CoV-2 inactivation protocols were available for either formaldehyde (FA)-fixed or glutaraldehyde (GA)-fixed tissues. Therefore, representative tissue from ferrets and hamsters was spiked with 2.2 × 106 tissue culture infectious dose 50% per ml (TCID50/ml) SARS-CoV-2 or were obtained from mice experimentally infected with SARS-CoV-2. SARS-CoV-2 inactivation was demonstrated with 4% FA or 5% GA at room temperature for 72 hours by a titer reduction of up to 103.8 TCID50/ml in different animal tissues with a maximum protein content of 100 µg/mg and a thickness of up to 10 mm for FA and 8 mm for GA. Our protocols can be easily adapted for validating the inactivation of other pathogens to allow for the transfer of biological samples from BSL-3 areas to BSL-1 laboratories.

Is online-only learning as effective as blended learning? A longitudinal study comparing undergraduate students' performance in oral radiology.

INTRODUCTION: Blended learning seems to be an effective teaching concept in oral radiology. During the COVID-19 pandemic, blended learning shifted towards online-only learning. The aim of the present study was to compare the effectiveness of pandemic online-only and pre-pandemic blended learning in three consecutive oral radiology courses (C1, C2 and C3) and to examine whether additional video-based e-learning modules (VBLMs) had a positive impact on undergraduate students' performance during pandemic semesters. MATERIALS AND METHODS: Data from 205 undergraduate dental students participating either in a blended learning or an online-only learning concept were analysed. Pre-pandemic blended learning comprised face-to-face seminars and access to an oral radiology platform (ORP). Pandemic online-only learning comprised online seminars, access to the ORP and additional VBLMs (two VBLMs for C1, four VBLMs for C2 and six VBLMs for C3). Through standardised e-exams at the beginning and end of each semester, performance in final exams and knowledge gain were compared between the two groups. RESULTS: No significant differences in scores in final exams (p = .11) and knowledge gain (p = .18) were found when comparing the pre-pandemic and pandemic groups. On course level, however, students receiving a lower number of VBLMs performed significantly worse in final exams (C1: p < .01, C2: p = .02) and showed inferior knowledge gain (C2: p < .01) during the pandemic. CONCLUSIONS: Within the limitations of the study, the present investigation confirmed that pandemic online-only learning involving VBLMs might be as effective as pre-pandemic blended learning.

Clinical efficacy of guided bone regeneration in peri-implantitis defects. A network meta-analysis.

Guided bone regeneration (GBR) at peri-implantitis-related bone defects involves the placement of bone-filler particles in the intrabony defects and the application of a barrier membrane. The efficacy of different GBR-supported reconstructive measures as well as their potential superiority compared to non-GBR-supported treatment strategies for bone defects at peri-implantitis sites, however, remains unclear. Therefore, this analysis was designed to evaluate the long-term (≥12 months) clinical efficacy of GBR-supported reconstructive surgical therapy for peri-implantitis-related bone defects. In terms of resolving inflammation, the implementation of GBR protocols applying xenogenic bone substitutes yielded a higher reduction of bleeding on probing and probing depth value compared to the GBR protocol applying autogenous bone. Furthermore, for the changes in bleeding on probing and probing depths, GBR approaches using xenogenic bone showed superiority over the non-GBR treatments. Xenogenic bone with or without a barrier membrane was associated with improved radiographic bone levels and less soft tissue recession compared to the use of a GBR protocol implementing autogenous bone. Nonetheless, when interpreting this findings, the limited number of available studies with low to serious risk of bias and the short follow-up periods limited to 12 months should be considered.

Mediterranean diet component oleic acid increases protective lipid mediators and improves trabecular bone in a Porphyromonas gingivalis inoculation model.

AIM: Therapeutic modulation of bacterial-induced inflammatory host response is being investigated in gingival inflammation and periodontal disease pathology. Therefore, dietary intake of the monounsaturated fatty acid (FA) oleic acid (OA (C18:1)), which is the main component of Mediterranean-style diets, and saturated FA palmitic acid (PA (C16:0)), which is a component of Western-style diets, was investigated for their modifying potential in an oral inoculation model of Porphyromonas gingivalis. MATERIALS AND METHODS: Normal-weight C57BL/6-mice received OA- or PA-enriched diets (PA-ED, OA-ED, PA/OA-ED) or normal standard diet for 16 weeks and were inoculated with P. gingivalis/placebo (n = 12/group). Gingival inflammation, alveolar bone structure, circulating lipid mediators, and in vitro cellular response were determined. RESULTS: FA treatment of P. gingivalis-lipopolysaccharide-incubated gingival fibroblasts (GFbs) modified inflammatory activation, which only PA exacerbated with concomitant TNF-α stimulation. Mice exhibited no signs of acute inflammation in gingiva or serum and no inoculation- or nutrition-associated changes of the crestal alveolar bone. However, following P. gingivalis inoculation, OA-ED improved oral trabecular bone micro-architecture and enhanced circulating pro-resolving mediators resolvin D4 (RvD4) and 4-hydroxydocosahexaenoic acid (4-HDHA), whereas PA-ED did not. In vitro experiments demonstrated significantly improved differentiation in RvD4- and 4-HDHA-treated primary osteoblast cultures and reduced the expression of osteoclastogenic factors in GF. Further, P. gingivalis infection of OA-ED animals led to a serum composition that suppressed osteoclastic differentiation in vitro. CONCLUSIONS: Our results underline the preventive impact of Mediterranean-style OA-EDs by indicating their pro-resolving nature beyond anti-inflammatory properties.

Effectiveness of modified and control protocols for the surgical therapy of combined peri-implantitis-related defects. A retrospective analysis.

OBJECTIVES: To compare the clinical effectiveness of control and two modified protocols for surgical therapy of combined peri-implantitis-related defects. MATERIALS AND METHODS: A total of n = 36 patients (n = 40 implants) diagnosed with combined supra- and intrabony defects were identified for this retrospective analysis. All protocols considered access flap surgery, granulation tissue removal and implant surface decontamination using a titanium brush. The control combined protocol included implantoplasty at supracrestal/ buccal- and reconstructive therapy at intrabony components using a particulate natural bone mineral + a native collagen membrane (CM) (n = 11 patients, n = 11 implants, CP). The modified protocols included the augmentation at both supra- and intrabony defect components using either a collagen-stabilized natural bone mineral (BOC) (n = 15 patients, n = 15 implants, MP1), or BOC mixed with autogenous bone chips + CM (n = 10 patients, n = 14 implants, MP2). Linear mixed effects analyses were used to assess the changes in clinical parameters (i.e., bleeding on probing - BOP, probing pocket depth - PD, and mucosal recession - MR) over time (i.e., 6 and 12 months) and the impact of the treatment groups (CP, MP1, MP2). RESULTS: At 12 months, median BOP and PD reductions amounted to -58.33% and - 1.16 mm in the MP1, to -62.50% and -1.95 mm in the MP2, and to -66.67% and -0.83 mm in the CP groups, respectively. The associated MR changes ranged between 0.00 and 0.08 mm. The survival rates were 100% in all groups. CONCLUSIONS: All treatment protocols were associated with short-term improvements in the clinical parameters investigated.

Non-invasive oral implant position assessment: An ex vivo study using a 3D industrial scan as the reference model to mimic the clinical situation.

AIM: To introduce an objective method to evaluate the accuracy of implant position assessment in partially edentulous patients by comparing different techniques (conventional impression, intraoral scan, CBCT) to a reference 3D model obtained with an industrial scanner, the latter mimicking the clinical situation. MATERIALS AND METHODS: Twenty-nine implants were placed in four human cadaver heads using a fully guided flapless protocol. Implant position was assessed using (a) a conventional impression, (b) an intraoral scan, and (c) CBCT and compared to an industrial scan. Three-dimensional models of intraoral scan body and implant were registered to the arch models and the deviation at implant shoulder, apex, and the angle of deviation were compared to each other as well as to the reference model. RESULTS: The three assessment techniques showed statistically significant deviations (p < .01) from the industrial scan, for all measurements, with no difference between the techniques. The maximum deviation at the implant shoulder was 0.16 mm. At the implant apex this increased to 0.38 mm. The intraoral scan deviated significantly more than the CBCT (0.12 mm, p < .01) and the conventional impression (0.10 mm, p = .02). The maximum implant angle deviation was 1.0°. The intraoral scan deviated more than the conventional impression (0.3°, p = .02). CONCLUSION: All assessment techniques deviated from the reference industrial scan, but the differences were relatively small. Intraoral scans were slightly less accurate than both conventional impressions and CBCT. Depending on the application, however, this inaccuracy may not be clinically relevant.

Autoclaving-induced dimensional changes of three-dimensional printed surgical guides: An in vitro study.

OBJECTIVES: Surgical guides are frequently used for dental implant placement. The aim of this study was to evaluate the impact of the 3D printing process itself and subsequent steam autoclaving on the dimensional stability of five different resin/printer combinations (RPCs). MATERIALS AND METHODS: Fifty identical surgical guides (10 per group) were produced consisting of five RPCs. Half of the guides (5 per group) were steam autoclaved with cycle 1 (121°C, 1 bar, 20.5 min) and the other half with cycle 2 (134°C, 2 bar, 5.5 min). All guides were scanned with a structured-light (SL) 3D scanner before (T0) and after (T1) autoclaving. Linear measurements along the x-, y-, and z-axes were performed at landmarks on the original STL file and on SL scans at T0 and T1, respectively. Wilcoxon signed-rank test, Kruskal-Wallis test, and linear mixed-effects models were performed, depending on the analysis. RESULTS: Three-dimensional printing was associated with significant dimensional alterations for all RPCs. Steam autoclaving using cycle 1 was associated with significant shrinkage in x- (1 RPC), y- (2 RPCs), and z-direction (2 RPCs), while cycle 2 was also associated with shrinkage in x- (2 RPCs), y- (1 RPC), and z-direction (1 RPC). One resin did not present any dimensional changes independently of the cycle. CONCLUSIONS: The majority of the guides presented minor but significant shrinkage due to 3D printing itself and both steam autoclaving cycles, the extent varied between different RPCs. Whether these changes compromise implant placement accuracy remains to be investigated.

Influence of antiresorptive/antiangiogenic therapy on the extension of experimentally induced peri-implantitis lesions.

OBJECTIVES: To investigate the extension of experimentally induced peri-implantitis lesions under various antiresorptive and antiangiogenic medications. MATERIAL AND METHODS: Fourty-eight albino rats had randomly received the following medications (dual application, n = 8 each): (1) amino-bisphosphonate (zoledronate) (Zo), (2) RANKL inhibitor (denosumab) (De), (3) antiangiogenic (bevacizumab) (Be), (4) Zo+Be, (5) De+Be, or (6) no medication (Co). Ligature- and lipopolysaccharide-induced peri-implantitis lesions were established at 2 maxillary implants over a period of 16 weeks. Histological (e.g., apical extension and surface area of the inflammatory cell infiltrate-aICT, ICT; defect length; defect width; CD68 positive cells) and bone micromorphometric (µCT) outcomes were assessed. The animal was defined as a statistical unit. RESULTS: A total of n = 38 animals (Zo = 6, De = 6, Be = 8, Zo + Be = 6, De + Be = 5, Co = 7) were analyzed. ICT's were commonly marked by a positive CD68 antigen reactivity. Comparable median aICT (lowest-Zo: 0.53 mm; highest-Be: 1.22 mm), ICT (lowest-De + Be: 0.00 mm2; highest-Co: 0.49 mm2), defect length (lowest-Zo: 0.90 mm; highest-Co: 1.93 mm) and defect width (lowest-De+Be: 1.27 mm; highest-Be: 1.80 mm) values were noted in all test and control groups. Within an inner (diameter: 0.8 mm) cylindric volume of interest, the bone microstructure did not significantly differ between groups. CONCLUSIONS: The present analysis did not reveal any marked effects of various antiresorptive/ antiangiogenic medications on the extension of experimentally induced peri-implantitis lesions. CLINICAL RELEVANCE: The extension of peri-implantitis lesions may not be facilitated by the antiresorptive and antiangiogenic medications investigated.

Efficacy of rehabilitation with different approaches of implant-supported full-arch prosthetic designs: A systematic review.

AIM: To evaluate the efficacy of different types of rehabilitation with fixed or removable full-arch implant-supported prosthesis designs in terms of implant loss and success in patients with at least one edentulous jaw, with tooth loss mainly due to periodontitis. MATERIALS AND METHODS: Clinical studies with at least 12 months reporting on implant loss and implant success were searched. Meta-analysis was conducted to estimate cumulative implant loss considering different prostheses designs. RESULTS: A total of 11 studies with unclear to low risk of bias were included in the analysis. Estimated cumulative implant loss for fixed prostheses within 1 year and 5 years was 0.64% (95% confidence interval [CI]: 0.31%-1.31%) and 1.85% (95% CI: 0.85%-3.95%), respectively. The corresponding values for removable prostheses amounted to 0.71% (95% CI: 0.22%-2.28%) and 4.45% (95% CI: 2.48%-7.85%). Peri-implantitis affected 10%-50% of the patients restored with implant-supported fixed prostheses. CONCLUSIONS: Based on the limited low-quality data, the present analysis points to a low and similar cumulative implant loss within 1 year for patients with tooth loss mainly due to stage IV periodontitis restored with either removable or fixed implant-supported full-arch prosthesis. At 5 years of functioning, there was a tendency for better outcomes using fixed designs.

Micro-angiogenic patterns around orthodontic implants migrating in bone: A micro-CT study in the rat tail model.

AIM: Recent studies revealed that implants can migrate in bone when subjected to continuous loading. Since this process is suspected to be accompanied by bone remodelling, which requires blood vessel formation, the present work aimed at assessing the micro-angiogenic patterns around migrating implants. MATERIALS AND METHODS: In 16 rats, two customized implants were placed in a single tail vertebra and connected with contraction springs (forces: 0 N, 0.5 N, 1.0 N, 1.5 N). After 2 or 8 weeks of loading, the animals were scanned by micro-CT before and after vasculature perfusion with a silicone rubber. Vessels were segmented by subtraction of the two micro-CT scans. Vessel thickness (V.Th), vessel volume per total volume (VV/TV), and vascular spacing (V.Sp) were assessed in a peri-implant volume of interest (VOI) around each implant. RESULTS: At 2 weeks of loading, force magnitude was significantly associated with VV/TV and V.Th values (χ2  = 10.942, p < .001 and χ2  = 6.028, p = .010, respectively). No significant differences were observed after 8 weeks of loading. CONCLUSIONS: Within the limitations of an animal study, peri-implant vessel thickness and density were associated with force magnitude in the early loading phase, whereas effects diminished after 8 weeks of loading.

Two-piece zirconia implants in the posterior mandible and maxilla: A cohort study with a follow-up period of 9 years.

OBJECTIVES: Long-term follow-up observations of zirconia implants are rare. This study aimed at evaluating the clinical performance of two-piece zirconia implants in the posterior jaws over 9 years. MATERIALS AND METHODS: Sixty partially edentulous patients were treated with two-piece zirconia implants. In eight no primary stability could be achieved. Fifty-two patients received the final restoration (i.e., cemented fibreglass abutments and all-ceramic crowns). After 2 years, 2 implants failed and 4 dropouts were recorded. The remaining 46 patients with one target implant each were recalled at 9 years. Besides implant survival, clinical parameters at the implant level (plaque index-PI, bleeding on probing-BOP, probing depth-PD, mucosal recession-MR) were recorded and compared with previously collected data. Mechanical and technical complications were assessed. RESULTS: Thirty patients responded. The mean observation period was of 111.1 ± 2.2 months. One implant was lost. Data recorded from the remaining 29 implants were analysed. PI values increased overtime. Mean BOP and PD remained unchanged during follow-up. No additional cases of peri-implantitis were recorded over the 10 diagnosed during the first 2 years of follow-up. No significant changes in mean MR values were detected over time, with 65% of the all included implants exhibiting no recession at 9 years and all the others, but one, a maximum MR of 1 mm. Three technical and 6 mechanical complications occurred in 7 patients between 2- and 9-years (6.9% and 20.7%, respectively, at patient level). CONCLUSION: Within the limitations of the present study, a high survival rate was registered. Albeit frequent mechanical and technical complications, two-piece zirconia implants could represent a valid solution for the replacement of single teeth in the posterior jaws.

Effect of peri-implant mucosal thickness on esthetic outcomes and the efficacy of soft tissue augmentation procedures: Consensus report of group 2 of the SEPA/DGI/OF workshop.

OBJECTIVES: The aim of this study was to comprehensively assess the literature in terms of the effect of peri-implant mucosal thickness on esthetic outcomes and the efficacy of soft tissue augmentation procedures to increase the mucosal thickness with autogenous grafts or soft tissue substitutes. MATERIAL AND METHODS: Two systematic reviews (SR) were performed prior to the consensus meeting to assess the following questions. Review 1, focused question: In systemically healthy patients with an implant-supported fixed prosthesis, what is the influence of thin as compared to thick peri-implant mucosa on esthetic outcomes? Review 2, focused question 1: In systemically healthy humans with at least one dental implant (immediate or staged implant), what is the efficacy of connective tissue graft (CTG), as compared to absence of a soft tissue grafting procedure, in terms of gain in peri-implant soft tissue thickness (STT) reported by randomized controlled clinical trials (RCTs) or controlled clinical trials (CCTs)? Review 2, focused question 2: In systemically healthy humans with at least one dental implant (immediate or staged implant), what is the efficacy of CTG, as compared to soft tissue substitutes, in terms of gain in peri-implant STT reported by RCTs or CCTs? The outcomes of the two SRs, the consensus statements, the clinical implications, and the research recommendations were discussed and subsequently approved at the consensus meeting during the group and plenary sessions. CONCLUSIONS: There was a tendency of superior esthetic outcomes in the presence of a thick mucosa. The connective tissue graft remains the standard of care in terms of increasing mucosa thickness.

Computer-assisted mitotic count using a deep learning-based algorithm improves interobserver reproducibility and accuracy.

The mitotic count (MC) is an important histological parameter for prognostication of malignant neoplasms. However, it has inter- and intraobserver discrepancies due to difficulties in selecting the region of interest (MC-ROI) and in identifying or classifying mitotic figures (MFs). Recent progress in the field of artificial intelligence has allowed the development of high-performance algorithms that may improve standardization of the MC. As algorithmic predictions are not flawless, computer-assisted review by pathologists may ensure reliability. In the present study, we compared partial (MC-ROI preselection) and full (additional visualization of MF candidates and display of algorithmic confidence values) computer-assisted MC analysis to the routine (unaided) MC analysis by 23 pathologists for whole-slide images of 50 canine cutaneous mast cell tumors (ccMCTs). Algorithmic predictions aimed to assist pathologists in detecting mitotic hotspot locations, reducing omission of MFs, and improving classification against imposters. The interobserver consistency for the MC significantly increased with computer assistance (interobserver correlation coefficient, ICC = 0.92) compared to the unaided approach (ICC = 0.70). Classification into prognostic stratifications had a higher accuracy with computer assistance. The algorithmically preselected hotspot MC-ROIs had a consistently higher MCs than the manually selected MC-ROIs. Compared to a ground truth (developed with immunohistochemistry for phosphohistone H3), pathologist performance in detecting individual MF was augmented when using computer assistance (F1-score of 0.68 increased to 0.79) with a reduction in false negatives by 38%. The results of this study demonstrate that computer assistance may lead to more reproducible and accurate MCs in ccMCTs.

Volumetric analysis of the periodontal microstructure under antiresorptive therapy: an experimental study in rabbits.

OBJECTIVES: The objective of this study was to volumetrically assess changes in the periodontal microstructure under antiresorptive therapy. MATERIALS AND METHODS: Microtomographic scans from a total of 9 Dutch Belted rabbits having been randomly allocated to either the intravenous administration of amino-bisphosphonate (zoledronic acid) (Za) (n = 5) or a negative control group (nZa) (n = 4) were obtained at 10 months following a repeated drug administration. A quantification of the periodontal space thickness (P.Th) of both maxillary and mandibular most posterior premolars, as well as of the 2nd molars was performed. Bone micromorphometry was assessed by means of bone volume per total volume (BV/TV), the bone mineral density (BMD), trabecular thickness (Tb.Th), trabecular number (Tb.N), bone surface (BS), and the specific bone surface (BS/BV). RESULTS: Za was associated with significantly higher P.Th (P = 0.010), which was most pronounced in the upper jaw. Bone micromorphometry revealed no significant differences among the two groups, i.e., Za and nZa, for all the investigated parameters. CONCLUSIONS: Volumetric analysis revealed that antiresorptive therapy was associated with periodontal space widening, whereas major effects on the bone micro-morphology could not be observed. CLINICAL RELEVANCE: A deep understanding of specific periodontal and alveolar bone alterations in patients under antiresorptive therapy might help to prevent the onset of medication-related osteonecrosis of the jaw.

Impact of metal artefacts on subjective perception of image quality of 13 CBCT devices.

OBJECTIVES: The overall objective of this study was to assess how metal artefacts impact image quality of 13 CBCT devices. As a secondary objective, the influence of scanning protocols and field of view on CBCT image quality with and without metal artefacts was also assessed. MATERIALS AND METHODS: CBCT images were acquired of a dry human skull phantom considering three clinical simulated conditions: one without metal and two with metallic materials (metallic pin and implant). An industrial micro-CT was used as a reference to register the CBCT images. Afterwards, four observers evaluated 306 representative image slices from 13 devices, ranking them from best to worst. Furthermore, within each device, medium FOV and small FOV standard images were compared. General linear mixed models were used to assess subjective perception of examiners on overall image quality in the absence and presence of metal-related artefacts (p < 0.05). RESULTS: Image quality perception significantly differed amongst CBCT devices (p < 0.05). Some devices performed significantly better, independently of scanning protocol and clinical condition. In the presence of metal artefacts, medium FOV standard scanning protocols scored significantly better, while in the absence of metal, small FOV standard yielded the highest performance. CONCLUSIONS: Subjective image quality differs significantly amongst CBCT devices and scanning protocols. Metal-related artefacts may highly impact image quality, with a significant device-dependent variability and only few scanners being more robust against metal artefacts. Often, metal artefact expression may be somewhat reduced by proper protocol selection. CLINICAL RELEVANCE: Metallic objects may severely impact image quality in several CBCT devices.

SARS-CoV-2 Infection Dysregulates Cilia and Basal Cell Homeostasis in the Respiratory Epithelium of Hamsters.

Similar to many other respiratory viruses, SARS-CoV-2 targets the ciliated cells of the respiratory epithelium and compromises mucociliary clearance, thereby facilitating spread to the lungs and paving the way for secondary infections. A detailed understanding of mechanism involved in ciliary loss and subsequent regeneration is crucial to assess the possible long-term consequences of COVID-19. The aim of this study was to characterize the sequence of histological and ultrastructural changes observed in the ciliated epithelium during and after SARS-CoV-2 infection in the golden Syrian hamster model. We show that acute infection induces a severe, transient loss of cilia, which is, at least in part, caused by cilia internalization. Internalized cilia colocalize with membrane invaginations, facilitating virus entry into the cell. Infection also results in a progressive decline in cells expressing the regulator of ciliogenesis FOXJ1, which persists beyond virus clearance and the termination of inflammatory changes. Ciliary loss triggers the mobilization of p73+ and CK14+ basal cells, which ceases after regeneration of the cilia. Although ciliation is restored after two weeks despite the lack of FOXJ1, an increased frequency of cilia with ultrastructural alterations indicative of secondary ciliary dyskinesia is observed. In summary, the work provides new insights into SARS-CoV-2 pathogenesis and expands our understanding of virally induced damage to defense mechanisms in the conducting airways.

Summary of European guidelines on infection control and prevention during COVID-19 pandemic.

OBJECTIVES: The current COVID-19 pandemic highlighted the need for a review of guidelines on infection control and prevention to ensure safe delivery of dental care. However, it is not clear to what extent the rapidly published European guidelines reflect the current evidence and thus provide homogeneous recommendations. MATERIAL & METHODS: Guidelines from all European Union countries, Scotland, Switzerland and United Kingdom were retrieved. Information on triage, mouth rinse, personal protective equipment (PPE) for aerosol free/ generating procedures (non-AGP/AGP) and treatment of potentially infectious patients were summarized and compared with recommendations from international organizations (WHO, ECDC, CDC). RESULTS: All included countries (30/30) published COVID-19 guidelines in 2020. All countries recommended triage and to postpone non-urgent treatment of potentially infectious patients. Hydrogen peroxide (1%-1.5%) was the most frequently recommended antiseptic mouth rinse to reduce viral load (24/30). PPE for non-AGP treatments included mainly surgical masks (21/30) or FFP2/FFP3/N95 masks (16/30), whereas FFP2/FFP3 masks (25/30) and face shields (24/30) were recommended for AGP by the vast majority of guidelines. For high-risk/COVID positive patients, most countries recommended maximum protection and treatment in specialized dental clinics (22/30). CONCLUSION: There was general agreement among recommendations for triage, mouth rinse, and PPE during AGP and treatment of potentially infectious patients. In contrast, recommendations on PPE for non-AGP treatment varied considerably among the European countries possibly due to limited scientific evidence regarding transmission risk during non-AGP treatments.

COVID-19: Review of European recommendations and experts' opinion on dental care. Summary and consensus statements of group 5. The 6th EAO Consensus Conference 2021.

OBJECTIVES: The present work reports the EAO workshop group 5 and consensus plenary discussions and statements based on two reviews summarising European guidelines and experts' opinion on infection control and prevention (ICP) in dentistry during the pandemic. MATERIAL: Two manuscripts were presented at the 6th EAO Consensus Conference. The first study compared the most recent national guidelines/recommendations of European countries. The second paper was an experts' opinion-based survey on application of ICP regulation during the second wave. The outcome of COVID-19 group discussion was presented to all participants of the consensus to come to an agreement about the consensus statements and clinical recommendation. RESULTS: The dynamic of the pandemic had an impact on rapidly published and frequently updated national guidelines in Europe. As guidelines were not based on solid evidence, they were supplemented by experts' opinion on ICP in dentistry. The dental care should be guaranteed during the pandemic; however, in case of suspected or confirmed COVID-19 disease, the treatment should be postponed if possible. Remote triage and patient-related measures (i.e., social distancing, hand hygiene and mask wearing) were recommended to be the most efficient to reduce SARS-CoV-2 transmission. The type of personal protective equipment for dental staff should be adequate to the procedure and infection risk. CONCLUSIONS: Adequate infection control protocols have to be followed by healthcare professionals and patients to minimise the spreading of COVID-19. We foresee the importance of continuously updating the national dental guidelines, considering the evolution of the pandemic and new scientific evidence becoming available.