Neutrophilic polymorphonuclear leukocytes (neutrophils) are myeloid cells packed with lysosomal granules (hence also called granulocytes) that contain a formidable antimicrobial arsenal. They are ...terminally differentiated cells that play a critical role in acute and chronic inflammation, as well as in the resolution of inflammation and wound healing. Neutrophils express a dense array of surface receptors for multiple ligands, ranging from integrins to support their egress from bone marrow into the circulation and from the circulation into tissues, to cytokine/chemokine receptors that drive their navigation to the site of infection or tissue damage and also prime them for a second stimulus, to pattern recognition receptors and immunoglobulin receptors to facilitate the destruction and removal of infective agents or debridement of damaged tissues. When afferent neutrophil signals are proportionate and coordinated they will phagocytose opsonized and unopsonized bacteria, activating the nicotinamide adenine dinucleotide phosphate oxidase (respiratory burst) to generate reactive oxygen species, which augment the proteolytic destruction of microbes secured within the phagosome. A highly orchestrated process of apoptosis follows, forming membrane-bound substructures that are removed by macrophages. Neutrophils are capable of various other forms of programmed cell death, such as NETosis and pyroptotic cell death, as well as nonprogrammed cell death by necrosis. In recent years, research has revealed that neutrophils are capable of far more subtle cell-cell interactions than previously thought possible. This includes synthesis of various inflammatory mediators and also myeloid cell training within bone marrow, where epigenetic and metabolic signals associated with returning neutrophils that undergo reverse egress from tissues into the vasculature and back to bone marrow program a hyperreactive subset of neutrophils during myelopoiesis that are capable of hypersensitive reactions to microbial aggressors. These characteristics are evident in various neutrophil subsets/subpopulations, creating broad heterogeneity in the behavior and biological repertoire of these seemingly schizophrenic immune cells. Moreover, neutrophils are critical effector cells of adaptive and innate immunity, binding to opsonized bacteria and destroying them by extracellular and intracellular methods. The former creates substantial collateral host tissue damage, as they are less specific than T-cytotoxic cell-killing mechanisms, and in conditions such as peri-implantitis, where plasma cells and neutrophils dominate the immune infiltrate, bone and tissue destruction are rapid and appear relentless. Finally, the role of neutrophils as conduits for periodontal-systemic disease connections and for oxidative damage to act as a causal link between the two has only recently been realized. In this chapter, we attempt to expand on these issues, emphasizing the contributions of European scientists throughout a detailed appraisal of the benefits and side effects of neutrophilic inflammation and immune function.
Background: The antibacterial and anti‐inflammatory properties of Dead Sea magnesium chloride (MgCl2), citrus oil, and their combination were investigated. Citrus oil is composed of monoterpenes, in ...particular D‐limonene, which is known to inhibit growth of bacteria, fungi, and certain parasites.
Methods: Inhibition of Porphyromonas gingivalis in vitro was used to evaluate the antibacterial effect of a mixture of Dead Sea magnesium chloride and citrus oil and of each of the components. A subcutaneous chamber model in mice was used to assess the anti‐inflammatory effect of the mixture and the individual components. Leukocyte migration, tumor necrosis factor‐alpha (TNF‐α) secretion, and interleukin (IL)‐10 secretion were determined. Hydrocortisone was used as a positive control.
Results: Citrus oil had an antibacterial effect with a minimal inhibitory concentration (MIC) of 1 mg/ml, whereas MgCl2 at concentrations up to 10 mg/ml did not exhibit any antibacterial activity. However, a mixture of 10 mg/ml MgCl2 and 0.25 mg/ml citrus oil dramatically increased inhibition of bacterial growth. The combination of MgCl2 and the citrus oil resulted in lower levels of TNF‐α and leukocyte migration while maintaining the levels of IL‐10 compared to the control.
Conclusion: These findings suggest that a mixture of citrus oil and MgCl2 could be used as a natural antibacterial and anti‐inflammatory agent.
Background
Oral infection of mice with P. gingivalis induces periodontal inflammation and attachment loss. The aim of the present study was to investigate whether infection of mice with P. ...gingivalis, exacerbates the clinical course of experimental autoimmune encephalomyelitis (EAE)—a mouse model of multiple sclerosis (MS).
Methods
Induction of EAE was carried out by immunization of C57BL/6 mice with myelin oligodentrocyte glycoprotein (MOG35‐55). P. gingivalis infection was induced via subcutaneous chambers model and the oral gavage. The severity of EAE was measured using a clinical severity score. Ex‐vivo reactivation of lymphocytes with the encephalitogenic peptide MOG35‐55 was also tested.
Results
Subcutaneous as well as oral infection with live P. gingivalis led to significant aggravation of the severity of EAE. Lymph node cells harvested from mice with EAE following P. gingivalis infection showed augmented lymphocyte proliferation towards the encephlatigenic MOG moiety compared to mice with EAE only.
Conclusions
The present results indicate that oral infection with P. gingivalis augmented the severity of EAE. This may stem from the systemic pro‐inflammatory response triggered by P. gingivalis infection or via antigen mimicking. The present study provides evidence that periodontal infection may play a role as modifier in CNS inflammatory disorders, such as MS.
Dental implants revolutionized the treatment options for restoring form, function, and esthetics when one or more teeth are missing. At sites of insufficient bone, guided bone regeneration (GBR) is ...performed either prior to or in conjunction with implant placement to achieve a three‐dimensional prosthetic‐driven implant position. To date, GBR is well documented, widely used, and constitutes a predictable and successful approach for lateral and vertical bone augmentation of atrophic ridges. Evidence suggests that the use of barrier membranes maintains the major biological principles of GBR. Since the material used to construct barrier membranes ultimately dictates its characteristics and its ability to maintain the biological principles of GBR, several materials have been used over time. This review, summarizes the evolution of barrier membranes, focusing on the characteristics, advantages, and disadvantages of available occlusive barrier membranes and presents results of updated meta‐analyses focusing on the effects of these membranes on the overall outcome.
Objective
To compare the early changes in implant stability of implants with different neck design during the first 3 months of healing in the posterior maxilla.
Materials and methods
Patients were ...randomized to receive triangular neck implant (test), or round neck implant (control). Resonance frequency analysis (ISQ) measurements were obtained at surgery and at 2, 4, 7, 14, 21, 28, 45, 60, and 90 days following implant placement. Non‐parametric statistic was used for data analysis.
Results
Thirty‐two patients were included (17 test and 15 controls). Initial ISQ values of the test implants were high (mean: 68.4, SD = 8.4) and increased over time (mean: 74.4, SD = 6.0). Control implants presented a statistically significant higher initial ISQ value at implant placement (mean: 76.9, SD = 8.7), which was maintained over the healing period (mean: 77.6, SD = 3.6) with no significant changes between time intervals. After 6 weeks of healing, both implants displayed comparable ISQ values with no differences between the groups. All implants exhibited a decrease in stability on days 2 and 21 post‐placement. All roundneck implants used, and 82% of the triangularneck implants showed initial ISQ values above the suggested threshold for immediate loading (>60).
Conclusions
Implant neck design plays a role in implant primary stability in the posterior maxilla. Both implants show high primary stability, with significantly higher values for the round neck. However, these differences disappeared after 6 weeks of healing. While primary implant stability is partially governed by implant neck design, the role of this result is negligible for the achievement of secondary stability.
Objectives
Implants with a triangular neck were recently introduced to limit peri‐implant bone loss. The primary objective of this randomized controlled trial was to compare peri‐implant bone changes ...of circular versus triangular cross‐section neck implants 1 year after loading. The secondary objectives were to assess buccal hard tissue thickness changes, Pink Esthetic Score (PES), and patient satisfaction.
Material and methods
Thirty four patients requiring replacement of the single, intercalated missing tooth of healed site for at least 4 months in the posterior maxilla were randomized into 2 groups according to the type of implant. Immediately after surgery and 1 year after final restoration, a cone beam CT (CBCT) was performed to assess proximal bone remodeling and buccal bone thickness. Peri‐implant soft tissue health, PES, and patient‐reported outcome measures (PROMs) were recorded.
Results
No implant loss occurred within the follow‐up period. The mean ± SD peri‐implant proximal bone loss 1 year after loading was 0.22 ± 0.30 mm for triangular and 0.42 ± 0.67 mm for circular implants necks (p = .25). Peri‐implant bone loss exceeding 2 mm was observed in a single implant in the circular neck group. Buccal bone thickness remained stable and did not differ different between the 2 groups. The peri‐implant soft tissue health, PES, and patient satisfaction were also comparable.
Conclusions
Within the limitations of the present study, patient clinical and radiographic outcomes did not differ between triangular and circular cross‐section neck implants in the posterior maxilla.
Background
The aim of the present in vitro study was to explore the possibility of using platelet‐rich fibrin (PRF) as a local sustained released device for antibiotics.
Materials and methods
...Platelet‐rich fibrin was prepared with the addition of antibiotics (5 mg/ml metronidazole; 150 mg/ml clindamycin; 1 mU/ml penicillin) or saline prior to centrifugation, while collagen sponges served as control. PRFs anti‐bacterial properties were examined in an anti‐biogram assay with Staphylococcus aureus or Fusobacterium nucleatum at different time intervals after PRF preparation.
Results
The addition of antibiotic solutions at volumes of 2 or 1 ml led to significant changes in PRF's physical properties, while the addition of 0.5 ml solution did not. PRF with saline showed minor anti‐bacterial activity, while all PRFs with antibiotics showed significant anti‐bacterial activity (p < 0.05). No differences were observed between raw (clot) and pressed (membrane) forms of PRF. Collagen sponges with and without antibiotics showed similar results to PRF. PRF and collagen sponges with antibiotics preserved their anti‐bacterial properties 4 days after preparation.
Conclusions
Platelet‐rich fibrin incorporated with antibiotics showed long‐term anti‐bacterial effect against F. nucleatum and S. aureus. This modified PRF preparation may be used to reduce the risk of post‐operative infection in addition to the beneficial healing properties of PRF.
Background
The aims of the present study were to compare the antibacterial effect of Er:YAG laser with other acceptable decontamination methods and to single out the optimal laser device parameters ...for effective bacterial elimination.
Methods
A multispecies biofilm which was composed of Streptococcus sanguis, Actinomyces naeslundii, Porphyromonas gingivalis, and Fusobacterium nucleatum was grown on sandblasted and acid‐etched (SLA, homogeneous moderately microrough, and nanosmooth surface) titanium disks. The biofilm was removed from the coated disks by hand curets, ultrasonic device, nylon brush (dental polishing prophy cup), or Er:YAG. Additionally, different parameter combinations of the laser machine were examined to reach an optimal lasing power for bacterial elimination/reduction. Residual biofilm samples were stained with bacterial live/dead staining and quantified using a fluorescent microscope.
Results
A multispecies biofilm was accumulated on the SLA titanium surfaces exhibiting cluster distribution next to bacteria‐poor areas. Hand curets, nylon brushes, and the ultrasonic device showed limited capability to effectively remove the biofilm from the SLA surfaces as opposed to the Er:YAG which displayed a superior ability to remove the biofilm. All Er:YAG parameter combinations that were evaluated as well as the tested “tip to target” distances showed similar excellent anti‐biofilm effects. Furthermore, we observed that the Er:YAG capability of biofilm removal is not only due to its light emission, but depends on its water irrigation as well.
Conclusions
Er:YAG laser has an excellent biofilm removal capability compared with hand curets, ultrasonic devices, or nylon brushes even when low energy parameters and low power settings are used. Additionally, an excellent antibacterial effect can be reached using a non‐contact mode of 1 to 5 mm “tip to target” distance.
Aim
To assess the efficacy and adverse effects of resective surgery compared to access flap in patients with periodontitis.
Methods
Randomized controlled trials with a follow‐up ≥6 months were ...identified in ten databases. Screening, data extraction, and quality assessment were conducted by two reviewers. The primary outcome was probing pocket depth, and the main secondary outcome was clinical attachment level. Data on adverse events were collected. Meta‐analysis was used to synthesize the findings of trials.
Results
A total of 880 publications were identified. Fourteen publications from nine clinical trials met the inclusion criteria and were included for analysis. Meta‐analysis was carried out using all available results. The results indicated superior pocket depth reduction following resective surgery compared to access flap after 6–12 months of follow‐up (weighted mean difference 0.47 mm; confidence interval 0.7–0.24; p = .010). After 36–60 months of follow‐up, no differences were found between the two treatments in pocket depth and attachment level. The prevalence of adverse effects was not different between the groups. Post‐operative recession tended to be more severe for the resective approaches.
Conclusion
Resective surgical approach was superior to access flap in reducing pocket depth 6–12 months post‐surgery, while no differences between the two modalities were found at 36–60 months of follow‐up.
To investigate the incorporation of the antifibrinolytic agent tranexamic acid (TA) during platelet-rich fibrin (PRF) formation to produce a robust fibrin agent with procoagulation properties.
Blood ...from healthy volunteers was collected. Into 3 tubes, TA was immediately added in 1-mL, 0.4-mL, and 0.2-mL volumes, and the fourth tube was without additions. After PRF preparation, the clots were weighed in their raw (clot) and membrane forms. PRF physical properties were analyzed using a universal testing system (Instron). Protein and TA levels in the PRF were analyzed using a bicinchoninic acid assay and a ferric chloride assay, respectively.
The addition of TA to PRF led to a robust weight compared with sham control. PRF weight was greater in females in all tested groups. The addition of TA also led to greater resilience to tears, especially at 1-mL TA addition to the blood. Furthermore, TA addition led to a greater value of total protein within the PRF and entrapment of TA in the PRF.
Addition of TA to a PRF preparation leads to robust PRF with greater protein levels and the amalgamation of TA into the PRF. Such an agent may enhance the beneficial properties of PRF and attribute procoagulation properties to it.
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