Dental unit waterlines (DUWLs) are highly susceptible to biofilm formation and serve as reservoirs for opportunistic waterborne pathogens, particularly Legionella pneumophila and Pseudomonas aeruginosa. Effective long-term control of microbial contamination remains challenging due to the complex architecture of DUWLs, intermittent water flow, and the limited applicability of thermal disinfection. Routine microbiological surveillance at the University Dental Clinic Vienna identified recurrent contamination of multiple dental units with L. pneumophila and P. aeruginosa. To establish an effective and sustainable water management strategy, three disinfection protocols were evaluated under routine clinical conditions: (A) continuous application of electrolytically generated hypochlorous acid (HOCl), maintaining a free chlorine concentration of 0.3-0.6 mg/L, (B) increased HOCl concentration, and (C) HOCl combined with hydrogen peroxide (H2O2). Water samples were analyzed according to standardized ISO methods for detection of L. pneumophila, P. aeruginosa, and heterotrophic plate counts (HPC). Protocol A demonstrated reliable balance between microbiological efficacy, technical compatibility, and operational feasibility. Increased HOCl concentrations provided no relevant additional microbiological benefit and were associated with technical impairments, whereas the combined HOCl/H2O2 protocol showed less microbiological performance. Following standardization to Protocol A, all evaluated units were incorporated into a comprehensive water safety program consisting of continuous disinfection, automated flushing procedures, daily free-chlorine monitoring, and routine microbiological surveillance. During the 3-year follow-up period (2023-2025), sustained suppression of L. pneumophila was achieved across the dental unit network, with only isolated residual findings in a single unit. Monitoring further demonstrated that low heterotrophic plate counts did not consistently exclude the presence of opportunistic pathogens, supporting the need for targeted pathogen surveillance in addition to routine HPC monitoring. These findings demonstrate that a standardized HOCl-based water safety program in combination with automated flushing protocols can provide sustainable long-term control of microbial contamination in DUWLs and underscore the importance of pathogen-specific monitoring for a comprehensive microbiological risk assessment.

Background/Objectives: The aim of this study was to show a standardized four-step technique that can offer individually personalized full-mouth therapy for each complex dental patient with erosive tooth wear resulting from bulimia nervosa, focusing on the individualized vertical dimension of occlusion (VDO), functional and aesthetic stability, and patient-reported outcomes, including dental symptoms, nutrition, self-perception, and quality of life. Methods: The following steps are proposed for structured full-mouth rehabilitation. Step 1: Intraoral diagnosis via a single computer-aided impression. Step 2: Determination of a new adequate vertical dimension of occlusion and soft tissue prediction. Step 3: Removable sample dentures-prototypes. Step 4: Non-prep/minimal-prep crowns as the long-term provisional/definitive treatment. Results: Nine adults (11% male) with dental erosion caused by bulimia nervosa (78%), gastro-esophageal reflux (11%), and soft drinks (11%) were part of this cohort. The novel digital workflow enabled restoration of an individualized vertical dimension of occlusion, stable occlusion, appropriate centric and eccentric contacts, biomimetic dental anatomy, harmonious tooth proportions, and optimized red-white aesthetics. Dental problems (hypersensitivity, dental pain), nutritional behavior, body perception, and quality of life improved after the full-mouth rehabilitation. Conclusions: The presented digital workflow offers a promising approach for full-mouth rehabilitation in patients with severe dental erosion, particularly associated with bulimia nervosa, enabling structured restoration planning and stepwise evaluation of the vertical dimension of occlusion and functional adaptation. Prospective studies with larger cohorts are needed to confirm long-term clinical outcomes and patient-reported benefits.

BackgroundThe assessment of immune responses plays a central role in evaluating the degree of protection after SARS-CoV-2 vaccination. The Abbott Alinity-I SARS-CoV-2 IgG II Quant Assay is widely used as a laboratory-based reference method for the quantitative assessment of anti-SARS-CoV-2 antibodies. In 2021, numerous rapid point-of-care antibody assays entered the market; however, their analytical performance and comparability with established automated platforms have not been comprehensively evaluated. The EDELVITAL fluorescence immunochromatographic assay is a fluorescence-based rapid test designed to assess neutralizing antibodies at the point of care. Early data demonstrated substantially increased infection risks among frontline healthcare personnel compared with the general population. In this context, reliable information on post-vaccination humoral immunity was of particular occupational and public health relevance. Given the limited independent validation data available for rapid assays, at this time, it was uncertain whether they reliably detected an adequate post-vaccination antibody response in comparison to gold standard methods. Therefore, this study aimed to evaluate the performance of a rapid point-of-care neutralizing antibody assay in vaccinated healthcare workers and to assess its concordance with the established Abbott Alinity I IgG assay. Because the two assays measure different aspects of the humoral immune response, the study also explored the potential complementary value of rapid neutralizing antibody testing in occupational health settings.MethodsA total of 334 serum samples from 291 COVID-19-vaccinated individuals were analyzed. IgG antibodies were quantified using the automated Abbott Alinity I CMIA, while neutralizing antibodies were measured using the EDELVITAL fluorescence immunochromatography test, calibrated to the WHO International Standard NIBSC 20/136 and SOP. Correlation and diagnostic analyses were performed.ResultsThe two assays showed a high level of agreement (95.5% of the EDELVITAL neutralizing assay results agreed with those from the Abbott Alinity I system) when it came to detecting positive results. The rapid point-of-care device presented reproducible neutralizing antibody results (positive/negative) within 15–20 min, aligning closely with the laboratory-based Abbott measurements.ConclusionsThe EDELVITAL fluorescence immunochromatographic assay showed analytical comparability with the Abbott Alinity I SARS-CoV-2 IgG II Quant Assay and may represent a practical complementary tool for antibody monitoring in healthcare workers. The rapid availability of its results can facilitate timely decisions regarding booster vaccination and occupational health management.

Long-term color match is one of the most important characteristics of aesthetic restorative materials as discoloration constitutes a primary reason for otherwise unnecessary replacements. The aim of the present in vitro study was to evaluate the color stability of frequent dental materials (ceramic, composite, orthodontic adhesive) induced by common antiseptic mouthrinses taking into account black tea consumption and mechanical cleaning. Twenty-four disc-shaped specimens (8 × 2 mm) were made of the materials Ceram.x Spectra™ ST HV, Ceram.x Spectra™ flow, Ceramill® Zolid HT+ PS and Unitek™ Transbond™ LR. Each of the following solutions was tested on six pieces per material: Chlorhexamed forte (CHX), octenident® (OCTD), octenimed® (OCTM) and artificial saliva (control). Dental samples underwent a total of 30 discoloration cycles in which they were alternatively placed into artificial saliva, black tea and respective mouthrinse or only in artificial saliva. After every 10 cycles, discs were mechanically cleaned with toothbrush and toothpaste. After 30 cycles, dental specimens were submitted to professional polishing. Color shifts were measured at different time-points using the VITA Easyshade® V spectrophotometer and displayed as total color difference ∆E (mean ± standard error). A post-hoc Tukey test (⍺ = 0.05) was applied to the mean ∆E values after 30 cycles to determine discoloration discrepancies between various mouthrinses as well as the control. Moreover, photos of individual discs were taken at all measurement times to visualize potential color changes by eye. All mouthrinses showed major color shifts in the clinically visible range compared to the control on all different dental materials tested. However, CHX caused significantly more discoloration than OCTM and OCTD. Established color changes could be almost completely removed by simple brushing and even further by professional polishing to clinically acceptable levels on all tested materials. Prolonged application of antiseptic mouthrinses may cause discoloration on different restorative materials. To maintain aesthetically satisfying conditions, patients should be educated about the importance of daily mechanical tooth brushing and regular professional polishing.

Low-level laser therapy (LLLT) is gaining attention as an effective adjunct to non-surgical periodontal treatment. This study evaluates the potential of LLLT to reduce bacterial load in a clinically relevant in vitro subgingival biofilm model and its impact on the inflammatory response. A subgingival biofilm model consisting of seven bacterial species was established. Primary human gingival fibroblasts (GFs) and periodontal ligament cells (PDLs) were cultured. Both biofilms and host cells were treated with the DenLase Diode Laser (980 nm) under various clinically relevant settings. The composition and structure of the seven-species biofilms were evaluated using quantitative PCR and fluorescence microscopy, respectively. The inflammatory response in host cells was analyzed by measuring the gene and protein expression levels of various inflammatory mediators. Laser treatment at power outputs ranging from 0.3 to 2 W had no significant effect on biofilm composition or architecture. LLLT, particularly at higher power settings, reduced the viability in both GFs and PDLs up to 70%. Gene expression levels of inflammatory mediators were only minimally influenced by laser treatment. However, LLLT significantly decreased the secretion of all examined cytokines. These findings suggest that LLLT with a 980 nm diode laser, under clinically relevant conditions, exerts anti-inflammatory rather than antimicrobial effects.

Low‐level laser therapy (LLLT) has been shown to exert biostimulatory effects, including increased cell proliferation and accelerated wound healing. Hence, the use of LLLT as an adjunct to scaling and root planing (SRP) for improved periodontal treatment outcomes has been examined. The aim of this study was to evaluate the clinical effect of adjunctive LLLT in the treatment of periodontitis with a 980-nm diode laser. Patients with a periodontal screening index of 3 or 4 who met the inclusion criteria were recruited and randomized into two groups for treatment allocation in a split-mouth design. The maxillary and mandibular left or right quadrants of the patients were assigned to either the test (SRP + LLLT) or the control (SRP) group. During the two final debridement sessions, LLLT was applied on one side of each study participant´s upper and lower jaws. The reevaluation of the clinical parameters and microbiological assays was performed 12 weeks after the initial therapy. Both groups presented significant reductions in clinical parameters (p < 0.001). However, no statistically significant differences between the test and control groups were found for any of the parameters (all p values were greater than 0.05). The recolonization of P. gingivalis and T. denticola was not significantly reduced in the laser group. The clinical parameters in both groups improved similarly after initial periodontal treatment. LLLT with the chosen settings did not show a beneficial effect during the initial nonsurgical treatment of periodontitis. LLLT is under discussion for periodontal therapy as a promising treatment modality. Compared with nonsurgical therapy alone, adjunctive periodontal treatment with a diode laser did not improve the clinical parameters of periodontitis patients in this study. Currently, there is no recommended treatment protocol for adjunctive LLLT in periodontitis, which needs to be further investigated with other laser settings. ISRCTN registry (#ISRCTN11275257), retrospectively registered, 16.10.2023.

BACKGROUND:The use of video teaching material is increasingly popular and has been useful under Covid-19 teaching circumstances, where practical courses have been somewhat limited according to the pandemic situation. The objective of this trial was to evaluate whether high-quality educational videos-viewed once or repeatedly-can effectively support dental students in acquiring practical skills for delivering oral hygiene instructions, while also enhancing their confidence and sense of safety. This study aims to contribute preliminary insights into the potential value of video-assisted learning in this specific context within dental education. METHODS:82 students from the 2nd term of dental school were enrolled in this study and randomly assigned to two groups. The participants watched two videos showing the application of the Bass toothbrushing method and the interdental brushing technique. Group 1 viewed the video only once, whereas Group 2 viewed the videos repeatedly every week on four consecutive weeks before the seminar. By the end of the four weeks, the students participated in a practical test by blinded examiners to evaluate the level of their obtained skills of oral hygiene instructions, demonstrated on a plastic model. The data analysis was conducted by an individual who was not involved in teaching or supervising the student courses. RESULTS:The results of this trial show that the students subjectively gained confidence in performing the techniques accurately, after watching the videos. The participants exhibited significant improvement in toothbrushing technique and applying the interdental brush after repetitive viewing of the videos compared to single viewing. There were no significant differences between groups regarding the assessment of the size of interdental spaces using a colorimetric probe. CONCLUSION:The findings of this trial support earlier studies indicating that video-based learning can serve as an effective resource for students in preclinical dental education, improving comprehension and practical skills. While enhanced technique and brush application were linked to multiple video viewings, the measurement of interdental spaces did not yield significant differences across groups.

Background: Periodontitis is an inflammatory condition initiated by oral bacteria and is associated with several systemic diseases. Quercetin is an anti-inflammatory and anti-bacterial poly-phenol present in various foods. The aim of this meta-analysis was the evaluation of the effects of quercetin administration in animal models of experimental periodontitis. Methods: A systematic search was performed in electronic databases using the following search terms: “periodontitis” or “periodontal disease” or “gingivitis” and “quercetin” or “cyanidanol” or “sophoretin” or “pentahydroxyflavone”. In vivo preclinical animal models of experimental periodontal disease with a measurement of alveolar bone loss were included in the analysis. The risk of bias of the included studies was assessed using the SYRCLE tool. Results: The systematic search yielded 335 results. Five studies were included, four of them qualified for a meta-analysis. The meta-analysis showed that quercetin administration decreased alveolar bone loss (τ2 = 0.31, 1.88 mm 95%CI: 1.09, 2.67) in experimental periodontal disease animal models. However, the risk of bias assessment indicated that four SYRCLE domains had a high risk of bias. Conclusions: Quercetin diminishes periodontal bone loss and prevents disease progression in animal models of experimental periodontal disease. Quercetin might facilitate periodontal tissue hemostasis by reducing senescent cells, decreasing oxidative stress via SIRT1-induced autophagy, limiting inflammation, and fostering an oral bacterial microenvironment of symbiotic microbiota associated with oral health. Future research will show whether and how the promising preclinical results can be translated into the clinical treatment of periodontal disease.

ObjectivesPart 1 of this study investigates the influence of zirconia types, chimney heights, and gingival heights on the strength of the zirconia-abutment-interface. Part 2 extends the analysis to include adhesive brands and macro-retentions.MethodsIn Part 1, the study utilized three zirconia types (700 MPa, 1000 MPa, 1200 MPa) to fabricate 234 screw-retained zirconia crowns with varying chimney heights (3.5 mm, 4.1 mm, 5 mm) and gingival heights (0.65 mm, 1.2 mm, 3 mm) of the titanium abutments. All adherend surfaces underwent sandblasting with aluminum oxide before cementation with a specific resin cement. In Part 2, the investigation of 240 screw-retained zirconia crowns focused on a single zirconia type (1000 MPa) with chimney heights of 3.5 mm and 5 mm and a gingival height of 0.65 mm of the titanium abutments, cemented with three different resin cements. All adherent surfaces underwent sandblasting with aluminum oxide before cementation, whereas 120 out of 240 abutments received additional macro retentions. Storage in water at 37 °C for 24 h preceded the tensile test.ResultsThe study revealed a substantial impact of chimney height and zirconia type on the bond strength of the zirconia-abutment-interface. Neither adhesive brands nor macro retentions significantly impacted the bond strength. Fracture incidence was significantly influenced by gingival height and zirconia type in part 1, whereas in part 2 smaller chimney heights correlated with a higher fracture incidence.SignificanceThis study contributes insights into the complex interplay of factors influencing the zirconia-abutment-interface. The results provide a foundation for refining clinical approaches, emphasizing the importance of chimney height and zirconia type in achieving successful anterior gap implant restorations.

IntroductionHuman periodontal ligament-derived mesenchymal stromal cells (hPDL-MSCs) possess a strong ability to modulate the immune response, executed via cytokine-boosted paracrine and direct cell-to-cell contact mechanisms. This reciprocal interaction between immune cells and hPDL-MSCs is influenced by 1,25-dihydroxyvitamin-D3 (1,25(OH)2D3). In this study, the participation of different immunomodulatory mechanisms on the hPDL-MSCs-based effects of 1,25(OH)2D3 on CD4+ T lymphocytes will be elucidated using different co-culture models with various cytokine milieus.Material and methodshPDL-MSCs and CD4+ T lymphocytes were co-cultured indirectly and directly with inserts (paracrine interaction only) or directly without inserts (paracrine and direct cell-to-cell contact interaction). They were stimulated with TNF-α or IL-1β in the absence/presence of 1,25(OH)2D3. After five days of co-cultivation, the CD4+ T lymphocyte proliferation, viability, and cytokine secretion were analyzed. Additionally, the gene expression of soluble and membrane-bound immunomediators was determined in hPDL-MSCs.ResultsIn the indirect and direct co-culture model with inserts, 1,25(OH)2D3 decreased CD4+ T lymphocyte proliferation and viability. The direct co-culture model without inserts caused the opposite effect. 1,25(OH)2D3 mainly decreased the CD4+ T lymphocyte-associated secretion of cytokines via hPDL-MSCs. The degree of these inhibitions varied between the different co-culture setups. 1,25(OH)2D3 predominantly decreased the expression of the soluble and membrane-bound immunomediators in hPDL-MSCs to a different extent, depending on the co-culture models. The degree of all these effects depended on the absence and presence of exogenous TNF-α and IL-1β.ConclusionThese data assume that 1,25(OH)2D3 differently affects CD4+ T lymphocytes via the paracrine and direct cell-to-cell contact mechanisms of hPDL-MSCs, showing anti- or pro-inflammatory effects depending on the co-culture model type. The local cytokine microenvironment seems to be involved in fine-tuning these effects. Future studies should consider this double-edged observation by executing different co-culture models in parallel.

Abstract Background Mesenchymal stromal cells (MSCs) isolated from the periodontal ligament (hPDL-MSCs) have a high therapeutic potential, presumably due to their immunomodulatory properties. The interaction between hPDL-MSCs and immune cells is reciprocal and executed by diverse cytokine-triggered paracrine and direct cell-to-cell contact mechanisms. For the first time, this study aimed to directly compare the contribution of various mechanisms on this reciprocal interaction using different in vitro co-culture models at different inflammatory milieus. Methods Three co-culture models were used: indirect with 0.4 μm-pored insert, and direct with or without insert. After five days of co-culturing mitogen-activated CD4+ T lymphocytes with untreated, interleukin (IL)-1β, or tumor necrosis factor (TNF)-α- treated hPDL-MSCs, the CD4+ T lymphocyte proliferation, viability, and cytokine secretion were investigated. The gene expression of soluble and membrane-bound immunomediators was investigated in the co-cultured hPDL-MSCs. Results Untreated hPDL-MSCs decreased the CD4+ T lymphocyte proliferation and viability more effectively in the direct co-culture models. The direct co-culture model without inserts showed a strikingly higher CD4+ T lymphocyte cell death rate. Adding IL-1β to the co-culture models resulted in substantial CD4+ T lymphocyte response alterations, whereas adding TNF resulted in only moderate effects. The most changes in CD4+ T lymphocyte parameters upon the addition of IL-1β or TNF-α in a direct co-culture model without insert were qualitatively different from those observed in two other models. Additionally, the co-culture models caused variability in the immunomediator gene expression in untreated and cytokine-triggered hPDL-MSCs. Conclusion These results suggest that both paracrine and cell-to-cell contact mechanisms contribute to the reciprocal interaction between hPDL-MSCs and CD4+ T lymphocytes. The inflammatory environment affects each of these mechanisms, which depends on the type of cytokines used for the activation of MSCs’ immunomodulatory activities. This fact should be considered by comparing the outcomes of the different models.

Mesenchymal stromal cells (MSCs) are multipotent, progenitor cells that reside in tissues across the human body, including the periodontal ligament (PDL) and gingiva. They are a promising therapeutic tool for various degenerative and inflammatory diseases. However, different heterogeneity levels caused by tissue-to-tissue and donor-to-donor variability, and even intercellular differences within a given MSCs population, restrict their therapeutic potential. There are considerable efforts to decipher these heterogeneity levels using different "omics" approaches, including single-cell transcriptomics. Previous studies applied this approach to compare MSCs isolated from various tissues of different individuals, but distinguishing between donor-to-donor and tissue-to-tissue variability is still challenging. In this study, MSCs were isolated from the PDL and gingiva of 5 periodontally healthy individuals and cultured in vitro. A total of 3,844 transcriptomes were generated using single-cell mRNA sequencing. Clustering across the 2 different tissues per donor identified PDL- and gingiva-specific and tissue-spanning MSCs subpopulations with unique upregulated gene sets. Gene/pathway enrichment and protein-protein interaction (PPI) network analysis revealed differences restricted to several cellular processes between tissue-specific subpopulations, indicating a limited tissue-of-origin variability in MSCs. Gene expression, pathway enrichment, and PPI network analysis across all donors' PDL- or gingiva-specific subpopulations showed significant but limited donor-to-donor differences. In conclusion, this study demonstrates tissue- and donor-specific variabilities in the transcriptome level of PDL- and gingiva-derived MSCs, which seem restricted to specific cellular processes. Identifying tissue-specific and tissue-spanning subpopulations highlights the intercellular differences in dental tissue-derived MSCs. It could be reasonable to control MSCs at a single-cell level to ensure their properties before transplantation.

Purpose: This study aimed to compare the clinical and radiographic outcomes of single posterior screw-retained monolithic implant crowns following a digital and conventional workflow and to report on the survival/complication rate after a mean 4-year follow-up. Materials and Methods: Thirty patients with a single posterior tooth missing were rehabilitated with a bone-level implant. After a healing period of ≥3 months, they were subjected to both a digital and conventional workflow to fabricate two screw-retained monolithic implant crowns. The quantitative clinical adjustments to both crowns (intrasubject comparison) and a questionnaire were recorded at try-in. Thereafter, a crown of the digital and conventional workflows was randomly inserted. At the last follow-up, the marginal bone level (MBL), peri-implant health-related parameters (bleeding on probing (BoP), plaque, pocket probing depth (PPD)), and functional implant prosthodontic score (FIPS) were assessed. Furthermore, the implant survival and success rates and technical complications were evaluated. Results: A total of 27 patients were followed for a mean period of 4.23 ± 1.10 years. There was no significant difference between the digital and conventional workflows regarding clinical adjustments and questionnaire outcomes. More than twice as many participants recommended digital (n = 16) compared to conventional impressions (n = 7) to friends. The implant survival and success rate were 100% and 96.3%, respectively. Furthermore, two de-cementations and one fracture of the ti-base abutment occurred. There were no significant differences in BoP, plaque, and PPD metrics between the two groups. The changes in the MBL between implant crown insertion (baseline) and the last follow-up were 0.07 ± 0.19 mm and 0.34 ± 0.62 mm in the digital and conventional groups, respectively (p = 0.195). The mean overall FIPS score was 8.11 ± 1.37 (range: 5–10). Conclusions: The clinical and radiographic outcomes of single screw-retained monolithic implant crowns were similar between both workflows after a mean of 4 years of service. The patients did not clearly prefer an impression technique for their restoration, although they would recommend the digital impression more often to friends. Thus, decision regarding clinical workflows may be based on the patient’s and/or clinician’s preference.

OBJECTIVES:This study aimed to assess levels of biomarkers associated with inflammation and tissue destruction in peri-implant crevicular fluid (PICF) of implants provided with customized or standard healing abutments during early implant healing.MATERIALS AND METHODS:Thirty implants were placed in 22 patients with partial posterior edentulism. Subsequently, test group implants (n=15) received one-piece titanium abutments that were fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM). Control group implants (n=15) were provided with standard abutments. PICF collection and standardized periapical radiographs were carried out at suture removal one week later, following crown delivery after 3 months and at 6 months. Expression of C-reactive protein (CRP), interferon-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12A, IL-17A, macrophage inflammatory protein (MIP)-1α, matrix metalloproteinase (MMP)-13, osteopontin, osteoactivin, Receptor Activator of NF-κB (RANK), and TGF-β were analyzed using a multiplex ELISA kit.RESULTS:Both groups showed a significant decrease in protein expression of CRP, IL-1β, IL-6, IL-8, MIP-1α, osteopontin, osteoactivin, and TGF-β, while MMP-13 levels increased during the observation period. A rise in OPG and RANK levels was detected among customized abutments. Expression of CRP was higher, whereas IL-1β, IL-1α, and MIP-1α were decreased in control compared to test group implants after 6 months. Marginal bone loss did not depend on abutment modality.CONCLUSIONS:Both abutment types showed distinctive temporal expression of inflammatory biomarkers during 6 months following implant placement.TRIAL REGISTRATION:ISRCTN98477184, registration date 18/05/2022 CLINICAL RELEVANCE: Customized healing abutments exert similar effects on inflammation during early implant healing compared to standard healing abutments.

Objectives This study aimed to evaluate the impact of enamel matrix derivative (EMD) application following subgingival instrumentation of residual pockets in periodontitis patients on inflammatory host response, microbiological composition, and clinical outcome. Methods In this double-blinded randomized controlled trial, a total of 22 patients with generalized periodontitis stage III or IV presenting with ≥ 6 mm probing pocket depth (PPD) at re-evaluation after initial periodontal therapy were included. Participants were randomly allocated at a 1:1 ratio to subgingival instrumentation with (EMD +) or without (EMD-) non-surgical EMD application into the pocket. PPD, clinical attachment level (CAL), bleeding on probing (BoP), plaque index (PI), as well as a panel of pro-inflammatory cytokines and periodontal pathogen count in the gingival crevicular fluid (GCF) of the respective sites were evaluated at baseline (T0) and six months afterwards (T1). Results Both treatment groups showed a significant PPD reduction (EMD + 1.33 ± 1.15 mm, p < 0.001; EMD- 1.32 ± 1.01 mm, p < 0.001) as well as CAL gain (EMD + 1.13 ± 1.58 mm, p < 0.001; EMD- 0.47 ± 1.06 mm, p = 0.005) from T0 to T1. While no intergroup differences for PPD reduction were observed, CAL gain was higher in EMD + sites compared to EMD- ( p = 0.009). No essential effects on cytokine expression as well as bacterial count were detected. Conclusions Application of EMD as an adjunct to subgingival instrumentation of residual pockets yielded benefits regarding CAL gain; however, effects on PPD reduction, inflammatory cytokines, and bacterial count were negligible. Trial registration ClinicalTrials.gov (NCT04449393), registration date 26/06/2020. Clinical relevance Based on the obtained results, additional non-surgical EMD application compared to subgingival instrumentation alone showed no clinically relevant effects on treatment outcome and underlying biological mechanisms.

The aim of this study was the evaluation of the in vitro efficacy of a carbon dioxide (CO2) laser, a tetracalcium phosphate/dicalcium phosphate anhydrate (TP/DP) desensitizer and the combination of the desensitizer and additional CO2 laser irradiation as a treatment modality for cervical dentin hypersensitivity. A total of 48 dental specimens, prepared from extracted human premolars and molars, were divided into four groups: a control group, a TP/DP desensitizer paste group, a CO2 laser (10.600-nm wavelength) group, and a paste and laser group. The specimens were coated with nail varnish except in the marked area and were then immersed in 2% methylene blue dye for 1 h. The specimens were then washed, dried, and cut longitudinally. Thereafter, photos of 40 dentin specimens were taken and evaluated. The area of penetration was assessed and reported as percentage of the dentin surface area. Additionally eight dental specimens were examined with the aid of a scanning electron microscope and evaluated. Significant differences in the penetration depth were found for all experimental groups compared to the control group. The lowest penetration area was detected in the paste-laser group (16.5%), followed by the laser (23.7%), the paste (48.5%), and the control group (86.2%). The combined treatment of the CO2 laser and a TP/DP desensitizer was efficient in sealing the dentinal surface and could be a treatment option for cervical dentin hypersensitivity.

Objectives: The use of lasers for debonding adhesively luted ceramic restorations is a rather recent oral laser application in dentistry. The removal of all-ceramic restorations in the mouth can often be a troublesome task. A novel method for the debonding of ceramic restorations without damaging the restorations is Er:YAG laser irradiation. The aim of this study was to evaluate the Er:YAG laser for debonding procedures of different dental ceramics and to identify appropriate laser settings. Material and methods: Lithium disilicate, zirconium-reinforced lithium silicate, feldspatic ceramic, and zirconium dioxide were investigated. Ten ceramic rectangular-shaped specimens with 1 and 2 mm thickness were produced from each material. All specimens were irradiated with four different power settings 1.5; 2.5; 3.5; 4.5 W, pulse duration 50 μs, laser repetition rate 10 Hz, time of irradiation 10 s. The transmitted energy was measured with a powermeter. Additionally the suitability of the Er:YAG laser to remove the adhesively bonded ceramic and the time until loss of retention was evaluated. Results: The transmission rate for 1 and 2 mm platelets was determined for zirconium-reinforced lithium silicate at 54.6%/35.6%, lithium disilicate at 53.2%/35.7%, zirconium dioxide at 40.6%/32.4%, and for the feldspathic ceramic at 19.4%/10.1%. For zirconium-reinforced lithium silicate and zirconium dioxide 2.5 W (250 mJ/10 Hz) was an appropriate energy level for effective debonding. Whereas for lithium disilicate and for feldspathic ceramic, 4.5 W (450 mJ/10 Hz) is required for efficient debonding. Conclusions: There are differences regarding transmission rates between ceramic types for the Er:YAG laser light and additionally depending on the type of ceramic different energy settings should be used for adequate debonding. Based on our in-vitro experiments we recommend 2.5 W for zirconium-reinforced lithium silicate and zirconium dioxide and 4.5 W for lithium disilicate and feldspatic ceramic. Transmission rates of different ceramic types and varying influences of thicknesses and bonding materials should be considered to adjust the laser parameters during laser debonding of adhesively luted all-ceramic restorations.

Introduction Human periodontal ligament-derived mesenchymal stromal cells (hPDL-MSCs) exhibit a tight bi-directional interaction with CD4 + T lymphocytes. The hPDL-MSCs’ immunomodulatory abilities are drastically enhanced by pro-inflammatory cytokines via boosting the expression of various immunomediators. 25-hydroxyvitamin D 3 (25(OH)D 3 ), the major metabolite of vitamin D3 in the blood, affects both hPDL-MSCs and CD4 + T lymphocytes, but its influence on their interaction is unknown. Methods Therefore, primary hPDL-MSCs were stimulated in vitro with tumor necrosis factor (TNF)-α a or interleukin (IL)-1β in the absence and presence of 25(OH)D 3 followed by an indirect co-culture with phytohemagglutinin-activated CD4 + T lymphocytes. The CD4 + T lymphocyte proliferation, viability, and cytokine secretion were analyzed. Additionally, the expression of various immunomediators in hPDL-MSCs was investigated, and their implication was verified by using pharmacological inhibitors. Results 25(OH)D 3 significantly counteracted the suppressive effects of IL-1β-treated hPDL-MSCs on CD4 + T lymphocyte proliferation, whereas no effects were observed in the presence of TNF-α. Additionally, 25(OH)D 3 significantly increased the percentage of viable CD4 + T lymphocytes via TNF-α- or IL-1β-treated hPDL-MSCs. It also caused a significant decrease in interferon-γ, IL-17A, and transforming growth factor-β productions, which were triggered by TNF-α-treated hPDL-MSCs. 25(OH)D 3 significantly decreased the production of various immunomediators in hPDL-MSCs. Inhibition of two of them, prostaglandin E2 and indoleamine-2,3-dioxygenase-1, partially abolished some of the hPDL-MSCs-mediated effects of 25(OH)D 3 on CD4 + T lymphocytes. Conclusion These data indicate that 25(OH)D 3 influences the immunomodulatory activities of hPDL-MSCs. This modulatory potential seems to have high plasticity depending on the local cytokine conditions and may be involved in regulating periodontal tissue inflammatory processes.

AbstractObjectivesPolymorphonuclear leucocytes (PMNs) constitute the first line of host defence and are crucial in maintaining periodontal health. Their survival and function are modulated by mesenchymal stromal cells (MSCs) from different origin. Gingival MSCs (GMSCs) play an important role in maintaining oral health and in the initial inflammatory response. The present study aimed to investigate the effects of GMSCs on PMNs apoptosis and reactive oxygen species (ROS) production.MethodsPMNs were either directly incubated with untreated, interleukin (IL)‐1β‐ or tumour necrosis factor (TNF)‐α‐treated GMSCs or stimulated with their conditioned media. Resulting ROS production was evaluated by dichlorofluorescin diacetate staining, whereas PMNs apoptosis was assessed by Annexin V staining, followed by flow cytometry analysis.ResultsWhile conditioned media of untreated and TNF‐α‐treated GMSCs did not affect apoptosis of PMNs, it was significantly delayed by conditioned media of GMSCs treated with IL‐1β. In direct co‐culture, GMSCs exerted anti‐apoptotic effects on PMNs independently of the previous stimulation. However, the strongest impact was observed by IL‐1β‐treated GMSCs. ROS production of PMNs was not influenced by GMSCs or their conditioned media.ConclusionThis study demonstrates for the first time the immunomodulatory properties of GMSCs towards PMNs, revealing that IL‐1β enhances anti‐apoptotic effects of GMSCs.