| 1. |
- Almohandes, Ahmed, et al.
(författare)
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Effect of biofilm formation on implant abutments with an anti-bacterial coating: A pre-clinical in vivo study
- 2021
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Ingår i: Clinical Oral Implants Research. - : Wiley. - 0905-7161 .- 1600-0501. ; 32:6, s. 756-766
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To analyse the long-term effect of plaque formation on implant abutments with an antibacterial coating and the ensuing host response in peri-implant tissues. Materials and methods Four implants were installed in each mandibular premolar region following tooth extraction in six dogs. Three months later, two test abutments with a titanium-bismuth-gallium (Ti-Bi-Ga) coating and two control titanium abutments were connected to the implants on each side of the mandible. After 2 months, ligatures were placed around the implants in one side of the mandible and plaque formation was allowed until the end of the experiment. The ligatures were removed after 4 weeks. Radiographs and microbiological samples were obtained from each implant site during the plaque formation period. Biopsies were obtained 8 months after abutment connection and prepared for histological analysis. Results The analysis did not reveal any statistically significant differences in bone loss, bacterial growth and size of inflammatory lesions between implant units with and without the Ti-Bi-Ga coating. Implant sites exposed to the short period of ligature-induced breakdown demonstrated more pronounced bone loss and bacterial growth than non-ligature sites. Conclusions It is suggested that a Ti-Bi-Ga coating does not prevent biofilm formation on the implant device and does not influence the ensuing host response in the adjacent peri-implant mucosa.
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| 2. |
- Basic, Amina, et al.
(författare)
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Antibiotic resistance among Aerobic Gram-Negative Bacilli isolated from patients with oral inflammatory dysbiotic conditions-a retrospective study
- 2024
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Ingår i: FRONTIERS IN DENTAL MEDICINE. - 2673-4915. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Aerobic Gram-Negative Bacilli (AGNB) are not part of the resident oral microflora but are occasionally found in high abundance under inflammatory dysbiotic conditions at various oral niches. The aim of the present study was to investigate the identity and antibiotic susceptibility of AGNB isolated from patients in Sweden with mucosal lesions, periodontitis, and peri-implantitis, with special attention to antibiotic resistance and on the presence of phenotypic Extended Spectrum Beta-Lactamase (ESBL) isolates. Materials and methods: Microbiolgical samples were harvested from 211 patients in total, experiencing mucosal lesions (N = 113), periodontitis (N = 62), or peri-implantitis (N = 36). The growth of AGNB's was semiquantified by selective and non-selective culture and the strains were isolated, identified, and tested for antibiotic susceptibility. A total of 251 AGNB strains, occurring in moderate to heavy growth (>100 CFU/ml sample), indicating a dysbiotic microbiota, were identified. The disc diffusion method was used for screening of the antibiotic susceptibility of the isolates. Phenotypic identification of ESBL isolates was based on resistance to ceftazidime and/or cefotaxime. Results: The most commonly detected AGNB isolates in oral inflammatory dysbiotic conditions were fermentative species belonging to Enterobacteriaceae e.g. Citrobacter spp., Enterobacter spp., Escherichia coli, Klebsiella spp, and the non-fermentative environmental Burkholderia cepacia, Pseudomonas spp., and Stenotrophomonas maltophilia. No clear trends were seen in frequency of the various species in samples from mucosal lesions, severe periodontitis, and peri-implantitis cases. The 138 Enterobacteriaceae isolates and 113 environmental AGNB isolated showed a high antibiotic resistance in general against antibiotics commonly used in dentistry (Amoxicillin, Amoxicillin + Clavulanic acid, Ampicillin, Clindamycin, Doxycycline, Erythromycin, Oxacillin, PenicillinV, and Tetracycline). The majority of these isolates were susceptible to ciprofloxacin. Ten isolates (4.1%) were phenotypically classified as ESBL positive. The ESBL isolates were predominantly found among isolates of S. maltophilia, while only one ESBL positive isolate was found among Enterobacteriaceae. Conclusions: Phenotypically identified ESBL isolates can occasionally be present among oral AGNB strains isolated in abundance from the dysbiotic microbiota occurring in cases with oral mucosal lesions, severe periodontitis, or peri-implantitis.
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| 3. |
- Basic, Amina, et al.
(författare)
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Microbial metabolites in the pathogenesis of periodontal diseases: a narrative review
- 2023
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Ingår i: Frontiers in Oral Health. - 2673-4842. ; 4
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Forskningsöversikt (refereegranskat)abstract
- The purpose of this narrative review is to highlight the importance of microbial metabolites in the pathogenesis of periodontal diseases. These diseases, involving gingivitis and periodontitis are inflammatory conditions initiated and maintained by the polymicrobial dental plaque/biofilm. Gingivitis is a reversible inflammatory condition while periodontitis involves also irreversible destruction of the periodontal tissues including the alveolar bone. The inflammatory response of the host is a natural reaction to the formation of plaque and the continuous release of metabolic waste products. The microorganisms grow in a nutritious and shielded niche in the periodontal pocket, protected from natural cleaning forces such as saliva. It is a paradox that the consequences of the enhanced inflammatory reaction also enable more slow-growing, fastidious, anaerobic bacteria, with often complex metabolic pathways, to colonize and thrive. Based on complex food chains, nutrient networks and bacterial interactions, a diverse microbial community is formed and established in the gingival pocket. This microbiota is dominated by anaerobic, often motile, Gram-negatives with proteolytic metabolism. Although this alternation in bacterial composition often is considered pathologic, it is a natural development that is promoted by ecological factors and not necessarily a true "dysbiosis". Normal commensals are adapting to the gingival crevice when tooth cleaning procedures are absent. The proteolytic metabolism is highly complex and involves a number of metabolic pathways with production of a cascade of metabolites in an unspecific manner. The metabolites involve short chain fatty acids (SCFAs; formic, acetic, propionic, butyric, and valeric acid), amines (indole, scatole, cadaverine, putrescine, spermine, spermidine) and gases (NH3, CO, NO, H2S, H-2). A homeostatic condition is often present between the colonizers and the host response, where continuous metabolic fluctuations are balanced by the inflammatory response. While it is well established that the effect of the dental biofilm on the host response and tissue repair is mediated by microbial metabolites, the mechanisms behind the tissue destruction (loss of clinical attachment and bone) are still poorly understood. Studies addressing the functions of the microbiota, the metabolites, and how they interplay with host tissues and cells, are therefore warranted.
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| 4. |
- Basic, Amina, et al.
(författare)
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The secretion of cytokines by peripheral blood mononuclear cells of patients with periodontitis and healthy controls when exposed to H2S
- 2021
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Ingår i: Journal of Oral Microbiology. - : Informa UK Limited. - 2000-2297. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Hydrogen sulfide(H2S) is a bacterial metabolite produced as a result of bacterial growth in subgingival pockets, suggested to partake in the pathogenesis of periodontitis. H2S has previously been shown to induce the secretion of the pro-inflammatory cytokines IL-1 beta and IL-18 via the NLRP3 inflammasome in monocytes. Objective: To investigate the non-NLRP3 inflammasome-dependent immunological response of human peripheral blood mononuclear cells (PBMCs) of periodontitis patients and healthy controls exposed to H2S in vitro. Methods: PBMCs of periodontitis patients(N = 31) and healthy controls(N = 32) were exposed to 1 mM sodium hydrosulfide (NaHS) at 37 degrees C for 24 h and the secretion of cytokines was compared to resting cells. TNF-alpha, IFN-gamma, IL-6, IL-8, IL-12p40, IL-12p70, IL-17, MCP-1, and IL-1Ra secretions were measured with Bio-Plex Pro (TM) Human Cytokine Assay. Results: H2S triggered the secretion of the pro-inflammatory IFN-gamma, IL-6, IL-17, TNF-alpha, IL-12p40, and IL-12p70, while the reverse was seen for IL-1Ra. In addition, a higher basal secretion of IFN-gamma, IL-6, IL-12p70, IL-17 and MCP-1 was seen from PBMCs of periodontitis patients compared to healthy controls. Conclusion: The bacterial metabolite H2S triggers the secretion of pro-inflammatory cytokines from PBMCs and may thus have a prominent role in the host-bacteria interplay in periodontitis.
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| 5. |
- Dahlén, Gunnar, 1944
(författare)
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Biofilms in Dental Unit Water Lines.
- 2021
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Ingår i: Monographs in oral science. - : S. Karger AG. - 1662-3843. ; 29, s. 12-18
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Forskningsöversikt (refereegranskat)abstract
- Biofilm formation has become a significant problem in dental unit water lines (DUWLs). The formation of biofilms and microbial growth in DUWLs leads to an unacceptably high number of microorganisms in the water used for spraying, cooling, and ultrasonication procedures. These procedures form aerosols which can be inhaled by the patients, and consequently dentistry constitutes an area of specific concern for patient safety. In particular, older and immunocompromised patients are at risk of serious respiratory tract infections if the water contains pathogens such as Legionella pneumophila and Pseudomonas spp. In the EU it is recommended that the water in DUWLs should not exceed 200 colony-forming units (CFU) of heterotrophic bacteria (bacteria living on organic material) per milliliter of water to be acceptable in dental work. A number of efficient products are available on the market that can be applied onto dental units. New dental units are nowadays equipped with "inbuilt" systems. Such measures have resulted in an acceptable standard of water in 95% of the 1,200 dental units in the Public Dental Health Service of the Västra Götalands region of Sweden that were followed yearly for 4 years. For the majority of the remaining DUWLs with an unacceptable standard this is due to neglect or inappropriate routines for water-cleaning procedures. It is the ability to follow instructions rather than the cleaning procedure itself that is decisive if clinics and dental units are to have an appropriate standard of water in their systems.
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| 6. |
- Dahlén, Gunnar, 1944, et al.
(författare)
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Current concepts and an alternative perspective on periodontal disease.
- 2020
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Ingår i: BMC oral health. - : Springer Science and Business Media LLC. - 1472-6831. ; 20:1
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Forskningsöversikt (refereegranskat)abstract
- Epidemiological data from countries worldwide show a consistent pattern implying that a fraction of around 10% of those over 40-50years in all populations will exhibit severe periodontitis with the potential risk of losing teeth during their life-time. The subgingival microbiota shows striking similarities between populations irrespective of disease severity and can only marginally explain the clinical pattern. It is also difficult to explain this pattern by genetic and acquired risk factors such as systemic disease (e.g. diabetes) or habits (e.g. smoking) even if they may have a confounding effect on the disease.Inflammation of the gingiva appears to be a normal and physiological response to the presence of commensal bacteria along the gingival crevice and in the dental biofilm. Over many years of exposure to the dental biofilm, the chronic inflammation in the gingiva gradually results in a loss of attachment and bone loss. Numerous laboratory and clinical studies have provided insight into the potential role of determinants that are associated with periodontitis. However, it has been difficult to relate the findings to the pattern of the distribution of the disease observed in epidemiological studies. We propose a simple and parsimonious model that considers all the multitude of potential determinants as creating effectively random noise within the dental biofilm to which the tissues react by accumulating the effects of this noise.We suggest that such a model can explain many of the epidemiological features of periodontal breakdown over time, and we discuss its clinical implications.
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| 7. |
- Ichioka, Yuki, et al.
(författare)
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In vitro evaluation of chemical decontamination of titanium discs
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Peri-implant diseases are caused by bacterial biofilm colonizing implant surfaces. Prevention and management of peri-implant mucositis and peri-implantitis rely on effective biofilm removal. This study aimed to evaluate biofilm removal and cytocompatibility following chemo-mechanical surface decontamination of biofilm-coated titanium discs. Biofilm-coated (Streptococcus gordonii) discs, with either non-modified (smooth) or modified (rough) surfaces, were instrumented using a sterile gauze soaked in one out of four solutions: saline (NaCl), alkaline electrized water (AEW), citric acid (CA) or N-acetyl-l-cysteine (NAC). Non-contaminated, untreated titanium discs served as controls (C). Residual deposits (bacteria and gauze fibers) and cytocompatibility for osteoblast-like cells were evaluated using SEM and immunofluorescence. Cytotoxicity was assessed using WST-8 assay and immunofluorescence. All protocols were equally effective in removing bacteria from smooth surfaces, while AEW and CA were found to be superior at rough surfaces. AEW and NAC were superior in promoting cytocompatibility over NaCl. NAC and CA had a strong cytotoxic effect on osteoblast-like and fibroblast cells. In conclusion, AEW may be beneficial in the decontamination of implant surfaces, effectively removing bacterial biofilm and restoring cytocompatibility.
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| 8. |
- Ichioka, Yuki, et al.
(författare)
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Mechanical removal of biofilm on titanium discs: An in vitro study
- 2022
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Ingår i: Journal of Biomedical Materials Research Part B-Applied Biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 110:5, s. 1044-1055
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this in vitro study was to evaluate surface cleanness and cytocompatibility following mechanical instrumentation of biofilm-contaminated titanium surfaces. Titanium discs (non-modified [Ti(s)] and shot-blasted surfaces [Ti(r)]) contaminated with Streptococcus gordonii were instrumented using four different techniques: (i) gauze soaked in saline (GS), (ii) ultra-sonic device (US), (iii) rotating nickel-titanium brush (TiB), or (iv) air-polishing device (AP). Non-contaminated, untreated titanium disks were used as controls (C). Residual deposits and cytocompatibility for osteoblast-like cells were evaluated using scanning electron microscopy, immunofluorescence, and reverse transcriptase polymerase chain reaction. While the number of residual bacteria on Ti(s) discs was close to 0 in all treatment groups, significantly higher mean numbers of residual bacteria were observed on Ti(r) discs for GS (152.7 +/- 75.7) and TiB (33.5 +/- 22.2) than for US (0) and AP (0). Instrumentation with US resulted in deposition of foreign material (mean area% of foreign material: 3.0 +/- 3.6% and 10.8 +/- 9.6% for Ti(s) and Ti(r) discs, respectively). AP was the most effective decontamination procedure in reducing bacteria without depositing residual foreign material on Ti(r) discs. TiB and AP were superior methods in restoring cytocompatibility, although no method of mechanical decontamination resulted in pristine levels of cytocompatibility.
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| 9. |
- Krishnan, Vinod, et al.
(författare)
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Acute and chronic infections affecting the oral cavity: orthodontic implications
- 2023
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Ingår i: Integrated Clinical Orthodontics. - 9781119870081 ; , s. 195-224
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Bokkapitel (refereegranskat)abstract
- Orthodontists are keen to correct facial and dental disfigurements, but often little attention is paid to the general health status of patients, as if the dentofacial region exists in isolation from the rest of the body. This approach can be termed "regional diagnosis," where an emphasis is placed on the face and oral cavity while ignoring the overwhelming evidence on an intimate association between dentofacial events and a multitude of pathophysiological developments throughout the rest of the body. Lack of adequate knowledge of infectious diseases can cause unnecessary delays in instituting appropriate therapy, and at the same time lead to failure in implementing proper safety measures for prevention of disease transmission to orthodontic office personnel. This chapter concentrates on nonodontogenic infections and their possible orthodontic implications. Systemic infectious diseases with oral manifestations and with a high degree of microbiological specificity are discussed, providing a clear guide to distinguish between bacterial, viral, fungal, and parasitic infections.
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| 10. |
- Nascimento, G. G., et al.
(författare)
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Periodontitis phenotypes and clinical response patterns to non-surgical periodontal therapy: reflections on the new periodontitis classification
- 2020
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Ingår i: European Journal of Oral Sciences. - : Wiley. - 0909-8836 .- 1600-0722.
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to identify response patterns to non-surgical periodontal therapy and to investigate whether the new classification system for periodontitis reflects response to treatment after 1 yr. At baseline, data on sociodemographic status, smoking, and diabetes were obtained from participants with periodontal disease. Clinical periodontal data and subgingival plaque were also collected. Participants underwent non-surgical periodontal therapy, and after 3 and 12 months, clinical data were reassessed. Factor analyses, group-based-trajectory modeling, and mixed-effects regression models were used for data analysis. Factor analysis of the baseline periodontal parameters revealed two different periodontitis dimensions: 'moderate' and 'severe'. Two response patterns for each of these periodontitis dimensions were identified. Periodontal therapy had a beneficial effect on both 'moderate' and 'severe' periodontitis; however, individuals with higher levels of disease at baseline experienced greater treatment effect. Regarding the new classification system, while the staging component distinguished different levels of 'moderate' and 'severe' periodontitis before and after treatment, the grading component did not. This study shows the beneficial effect of non-surgical periodontal therapy on both 'moderate' and 'severe' periodontitis. However, the benefit was limited among individuals with low levels of disease. The new classification system did not adequately reflect the periodontal response to therapy in this patient group.
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