Bruno Braga Benatti

Cannabidiol decreases bone resorption by inhibiting RANK/RANKL expression and pro-inflammatory cytokines during experimental periodontitis in rats.

Cannabidiol (CBD) is a cannabinoid component from Cannabis sativa that does not induce psychotomimetic effects and possess anti-inflammatory properties. In the present study we tested the effects of CBD in a periodontitis experimental model in rats. We also investigated possible mechanisms underlying these effects. Periodontal disease was induced by a ligature placed around the mandible first molars of each animal. Male Wistar rats were divided into 3 groups: control animals; ligature-induced animals treated with vehicle and ligature-induced animals treated with CBD (5 mg/kg, daily). Thirty days after the induction of periodontal disease the animals were sacrificed and mandibles and gingival tissues removed for further analysis. Morphometrical analysis of alveolar bone loss demonstrated that CBD-treated animals presented a decreased alveolar bone loss and a lower expression of the activator of nuclear factor-kappaB ligand RANKL/RANK. Moreover, gingival tissues from the CBD-treated group showed decreased neutrophil migration (MPO assay) associated with lower interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha production. These results indicate that CBD may be useful to control bone resorption during progression of experimental periodontitis in rats.

Inflammatory and bone-related genes are modulated by aging in human periodontal ligament cells.

Periodontal ligament cells (PDLC) play a major role in periodontal tissues homeostasis and destruction. Most age-associated diseases seem to be closely related to an underlying chronic inflammatory state. Thus, the present study aimed at evaluating in PDLC the effect of aging on the basal levels of inflammatory and bone-related genes. Primary PDLC cultures were obtained from subjects aged 15-20 years (control- n=5), and subjects aged more than 60 years (test- n=5). Proliferation, cell viability and total secreted protein assays were performed, and mRNA levels were quantitatively assessed for interleukin (IL)-1beta, IL-4, IL-6 and IL-8, and for receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegerin (OPG) by real time PCR. Data analysis demonstrated that aging negatively influenced cell proliferation, whereas cell viability and total secreted protein were not affected (p>0.05). Gene expression analysis showed that mRNA levels for RANKL and IL-8 were not affected by aging (p>0.05) whereas, mRNA levels for IL-4 was significantly lower in aged cells (p<0.05) and OPG, IL-1beta and IL-6 mRNA levels were higher (p<0.05). Data analysis suggests that aging decreased the ability of PDLC to proliferate and modulated the expression of important inflammatory and bone-related genes in periodontal ligament cells, favoring a proinflammatory and an antiresorptive profile.

Influence of Aging on Biological Properties of Periodontal Ligament Cells

The majority of patients eligible for periodontal regenerative therapies are aged subjects. Since periodontal ligament cells (PDLC) are essential for periodontal regeneration, the aim of the present study was to determine the effect of cellular aging on PDLC, including genes associated with extracellular matrix metabolism and growth-associated factors. PDLC cultures were obtained from subjects aged 15 to 20 years and subjects aged more than 60 years. Proliferation, cell viability, mineralization assays, and mRNA levels were assessed for type I and III collagen, platelet-derived growth factor (PDGF)-1, basic fibroblast growth factor (bFGF), metalloproteinase (MMP)-2 and-8, and tissue inhibitor of metalloproteinases (TIMP)-1 and-2. Data analysis demonstrated that aging negatively influenced cell proliferation and mineral nodule formation (p < 0.05). Gene expression analysis further showed that mRNA levels for bFGF, PDGF-1, and TIMP-2 were not affected by aging (p > 0.05). In addition, mRNA levels for type I and III collagen were significantly lower in aged cells (p < 0.05), whereas MMP-2 and-8 and TIMP-1 mRNA levels were higher (p < 0.05). Within the limits of the present study, data analysis suggests that aging modulates important biological properties of periodontal ligament cells, diminishes the potential for mineral nodule formation, and favors extracellular matrix degradation.

Evaluation of soft tissues around single tooth implants in the anterior maxilla restored with cemented and screw-retained crowns.

Implant-supported restorations can be attached as screw-retained or cemented prostheses. In both situations, the characteristics of the soft tissues around the implants are crucial for oral rehabilitation and patient satisfaction. Therefore, this study uses the Pink Esthetic Score (PES), which allows evaluation of gingival esthetics around implants, to evaluate the soft tissues around implants in the anterior maxilla rehabilitated with cemented prostheses (CP) and screw-retained prostheses (SP). Forty implants placed in the anterior maxilla were evaluated, and these had been rehabilitated with prosthetic crowns for a minimum of 1 year. Periodontal examination was performed to evaluate probing depth (PD) and bleeding on probing (BOP) of the implant and the corresponding natural tooth. The total mean (±SD) PES for SP was 10.73 (±1.98) and 10.41 (±2.67) for CP, which was not statistically significant (P ≥ .05). Periodontal examination revealed that CP and SP showed no difference for BOP (P ≥ .05). Differences were only detected in PD when comparing the reference teeth of both groups to CP and SP (P ≤ .05). The present study demonstrates that the PES proved to be an efficient index to assess peri-implant tissues, and that the type of crown retention does not influence the health and quality of the soft tissues around implants.

Possible evidence of systemic lupus erythematosus and periodontal disease association mediated by Toll-like receptors 2 and 4.

Toll‐like receptors (TLRs) participate in the innate immune response and trigger the immune responses of the body. Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown aetiology, characterized by an excessive autoimmune response in the body affecting the connective tissues. The disease is possibly triggered by both environmental aetiological factors and pathological organic processes such as exposure to sunlight, chronic infectious processes and genetic factors. Conversely, periodontal disease is an infectious disease caused by microorganisms in the oral cavity, resulting in a chronic inflammatory process which continuously stimulates the immune response, thus causing damage to the periodontal tissues. The expression of both TLR‐2 and TLR‐4 receptors are increased in both SLE and periodontal disease. Periodontitis might trigger excessive activation of immune response occurring in SLE by maintaining a high expression of TLRs, leading in turn to the acceleration of the onset and progression of autoimmune reactions. In addition, periodontal treatment is able to reduce the expression of these receptors and therefore the symptoms of SLE. Here we discuss the possible interaction between SLE and periodontitis, and suggest further studies evaluating common features in both factors that could explored, due to morbidity and mortality of SLE and the high incidence of periodontal infections around the world.

Intermittent Parathyroid Hormone Administration Improves Periodontal Healing in Rats

BACKGROUNDnIntermittent administration of parathyroid hormone (PTH) promotes new bone formation in patients with osteoporosis and bone fractures. It was shown previously that PTH also reduces periodontitis-related bone loss. The aim of this study is to evaluate the effect of treatment with PTH on periodontal healing in rats.nnnMETHODSnFenestration defects were created at the buccal surface of the distal root of the mandibular first molars, and both periodontal ligament (PDL) and cementum were removed. Animals were then assigned to two groups (eight animals per group): group 1: control, placebo administration; and group 2: test, human PTH (hPTH) 1-34 administration at a concentration of 40 μg/kg. For both groups, the animals were injected every 2 days, and the animals were sacrificed at 14 and 21 days after surgery. Specimens were harvested and processed for routine decalcified histologic sections. The following parameters were assessed: 1) remaining bone defect extension (RBDE); 2) newly formed bone density (NFBD); 3) total callus area (TCA); 4) osteoclast number (ON) in the callus region; and 5) newly formed dental cementum-like tissue (NFC). Birefringence of root PDL reattachment was also evaluated.nnnRESULTSnBirefringence analysis showed root PDL reattachment for both groups 21 days after treatment. Intermittent hPTH 1-34 administration decreased RBDE (P <0.01) and increased NFBD (P <0.01), TCA (P <0.01), area of NFC (P <0.01), and ON in the callus region (P <0.01).nnnCONCLUSIONnWithin the limits of the present study, intermittent administration of hPTH 1-34 led to an enhanced periodontal healing process compared with non-treated animals.

Effects of a Mikania laevigata extract on bone resorption and RANKL expression during experimental periodontitis in rats

Objectives The Mikania laevigata extract (MLE) (popularly known in Brazil as guaco) possesses anti-inflammatory properties. In the present study we tested the effects of MLE in a periodontitis experimental model in rats. We also investigated possible mechanisms underlying such effects. Material and Methods Periodontal disease was induced by a ligature placed around the mandibular first molars of each animal. Male Wistar rats were divided into 4 groups: non-ligated animals treated with vehicle; non-ligated animals treated with MLE (10 mg/kg, daily); ligature-induced animals treated with vehicle and ligature-induced animals treated with MLE (10 mg/kg, daily). Thirty days after the induction of periodontal disease, the animals were euthanized and mandibles and gingival tissues removed for further analysis. Results Morphometric analysis of alveolar bone loss demonstrated that MLE-treated animals presented a decreased alveolar bone loss and a lower expression of the activator of nuclear factor-κB ligand (RANKL) measured by immunohistochemistry. Moreover, gingival tissues from the MLE-treated group showed decreased neutrophil migration myeloperoxidase (MPO) assay. Conclusions These results indicate that MLE may be useful to control bone resorption during progression of experimental periodontitis in rats.

The Impact of Cigarette Smoke Inhalation on the Outcome of Enamel Matrix Derivative Treatment in Rats: Histometric Analysis

BACKGROUNDnTobacco use is the most significant risk factor of periodontal disease. Clinical evidence has demonstrated that tobacco may negatively influence the results after surgical and non-surgical periodontal therapy. Enamel matrix derivative (EMD) have been used in periodontal regenerative procedures resulting in improvement of clinical parameters. The effect of EMD in the presence of tobacco compounds is unclear. Thus, the aim of the present study is to evaluate the impact of cigarette smoke inhalation (CSI) on the results of EMD treatment.nnnMETHODSnTwenty-two Wistar rats were assigned to two groups: Group 1, CSI (n = 11); Group 2, non-exposed (n = 11). Thirty days after initiation of CSI, fenestration defects were created at the buccal aspect of the first mandibular molar. The study followed a split-mouth design. After the surgeries the defects were randomly assigned to two subgroups: non-treated control and treated with EMD. The animals were sacrificed 21 days later and the percentage of defect fill, density of newly formed bone, and new cementum formation were histometrically assessed. The number of osteoclasts was determined by tartrate-resistant acid phosphatase.nnnRESULTSnCSI was associated with less bone density compared to the non-exposed group. EMD provided an increased defect fill and new cementum formation in both groups. The number of tartrate-resistant acid phosphatase-positive osteoclasts was significantly higher in the CSI non-treated control group compared to the non-treated control of the non-exposed animals.nnnCONCLUSIONSnEMD may provide increased defect fill and cementum formation in the presence or absence of CSI. However, tobacco smoke produced a detrimental effect on bone healing when density of newly formed bone was considered.

Salivary levels of inflammatory cytokines and their association to periodontal disease in systemic lupus erythematosus patients. A case-control study.

Both Systemic Lupus Erythematosus (SLE) and periodontal disease (PD) present a similar immunological profile mainly characterized by altered cytokine levels. In this study we sought to investigate the salivary levels of inflammatory cytokines and their association with PD in SLE patients. 60 patients with SLE and 54 systemically healthy individuals underwent a full periodontal clinical examination. They were then grouped according to their periodontal status. Stimulated saliva was collected in order to evaluate the salivary levels of interferon (IFN-γ), Interleukin (IL)-10, IL-17, IL-1β, and IL-4. Systemically healthy individuals with periodontitis (group P) presented higher levels of cytokines when compared to systemically healthy individuals, with no periodontal disease (group S) (p<0.05). Additionally, in the P group, patients presented similar levels of cytokines to those of the patients with SLE, regardless of the presence of PD (p>0.05), for most of the analyzed cytokines. There was a positive correlation in SLE patients, including IL-1β and all periodontal clinical parameters (p<0.05), and between IL-4 and gingival bleeding index and the presence of biofilm (p<0.05). Thus, our results confirmed, that patients with PD showed higher salivary levels of cytokines and, in SLE patients, the increased levels of salivary cytokines were observed even in the absence of periodontitis. IL-1β and IL-4 salivary levels were also positively correlated with periodontal status indicating their potential as markers of the amount and extent of periodontal damage in patients with SLE.

Resveratrol Inhibits Periodontitis-Related Bone Loss in Rats Subjected to Cigarette Smoke Inhalation

BACKGROUNDnAlternative therapeutic approaches have been explored to modulate host response to periodontal disease. Knowledge of new strategies to treat periodontitis is particularly relevant in patients presenting augmented risk to periodontitis, such as smokers. The aim of this study is to investigate the impact of resveratrol (RESV) on progression of experimental periodontitis (EP) in the presence of cigarette smoke inhalation (CSI).nnnMETHODSnRats were assigned to one of three groups: 1) CSI+RESV (n = 20); 2) CSI+placebo (n = 20); and 3) non-CSI (n = 20). CSI was initiated 1 week prior to initiation of RESV or placebo administration (systemically for 30 days) and was continued until the end of the study. EP was induced around the first mandibular and second maxillary molars using ligatures. Specimens from the mandible were processed for morphometric and microcomputed tomography examination of bone volume/levels. Gingival tissues surrounding mandibular molars were collected for quantification of interleukin (IL)-1β, IL-4, IL-6, IL-17, and tumor necrosis factor-α using an assay system. Additional analyses of immunoinflammatory mediator performance (T-helper Type 17 [Th17]/Th2 and Th1/Th2 cell levels) were performed according to Th cell responses in gingival tissues. Gingival tissues of maxillary molars were subjected to real-time polymerase chain reaction for assessment of osteoprotegrin, runt-related transcription factor-2, receptor activator of nuclear factor-kappa B ligand (RANKL), sclerostin, and Dickkopf Wnt signaling pathway inhibitor 1 levels.nnnRESULTSnHigher linear alveolar bone loss (ABL) and lower interradicular bone density were detected in ligated molars in the CSI+placebo group (P <0.05). IL-4 level was the highest, and Th17/Th2 levels were the lowest in RESV-treated rats compared with placebo rats (P <0.05). RESV reduced expression of messenger RNA for RANKL in animals receiving CSI (P <0.05).nnnCONCLUSIONnRESV inhibits EP and CSI-induced supporting ABL and has a beneficial effect on osteo-immunoinflammatory markers.