Gingival fibroblasts respond to the TRPV1 agonist capsaicin

Background: The oral cavity is a frontline barrier which is often exposed to physical trauma and noxious substances, leading to pro-inflammatory responses designed to be protective in nature. The transient receptor potential (TRP) super family of ion channels is believed to play a critical role in sensory physiology, acting as transducers for thermal, mechanical and chemical stimuli. Our understanding of the role of TRP channel activation in gingival and periodontal inflammation is currently limited. Gingival fibroblasts are the most abundant structural cell in periodontal tissues and we hypothesised that they may have a role in the inflammatory response associated with TRP channel activation. Objectives: The present study was designed to determine whether the TRPV1 agonist capsaicin could elicit a pro-inflammatory response in gingival fibroblasts in vitro by up-regulation of interleukin-8 (IL-8) production. Methods: Gingival fibroblasts were derived by explant culture from surgical tissues following ethical approval. Cells were maintained in Dulbecco's modified Eagle's medium (DMEM), containing 10% fetal calf serum (FCS) in 5% CO2. Following treatment of gingival fibroblasts with capsaicin, IL-8 levels were measured by ELISA. The potential cytotoxicity of capsaicin was determined by the MTT assay. Results: In gingival fibroblasts treated with the TRPV1 agonist capsaicin (10µM), IL-8 production was significantly increased compared with untreated control cells. Capsaicin was shown not to be toxic to gingival fibroblasts at the concentrations studied. Conclusion: The identification of factors that modulate pro-inflammatory cytokine production is important for our understanding of gingival and periodontal inflammation. This study reports for the first time that gingival fibroblasts respond to the TRPV1 agonist capsaicin by increased production of IL-8. Activation of TRPV1 on gingival fibroblasts could therefore have an important role in initiating and sustaining the inflammatory response associated with periodontal diseases

Effects of LL-37 Peptide Mimetics on Gingival Fibroblast Function

Host defence peptides, including the cathelicidin LL-37, play an important role in mucosal immunity, functioning as both antimicrobial agents and modulators of the inflammatory response. In the current climate of antibiotic resistance, the idea of using naturally occurring antimicrobial peptides, or their synthetic mimetics, to combat oral infection is particularly appealing. Objectives: The aim of this study was to investigate the effects of parent LL-37, and two peptide mimetics (KR-12 and KE-18), on cytokine expression and response to bacterial challenge by gingival fibroblasts. Methods: KR-12 and KE-18 are peptide mimetics of the biologically active, mid-region sequence of LL-37. The effects of commercially available LL-37, KR-12 and KE-18 on gingival fibroblast response to E coli and P gingivalis LPS challenge, analysed by IL-6 and IL-8 expression, were determined in cell culture by ELISA. The direct effects of each peptide on IL-6, IL-8, CXCL-1 and HGF expression were also determined by ELISA. The MTT assay was used to evaluate peptide effects on fibroblast viability. Results: LL-37 and KE-18, but not KR-12, inhibited LPS induction of inflammatory cytokine expression and directly stimulated CXCL-1 production by fibroblasts. All 3 peptides stimulated production of IL-8 and HGF. Neither LL-37 nor KE-12 affected cell viability, while KE-18, at higher concentrations, induced cell death. Conclusions: Shorter, peptide mimetics of LL-37, in particular KE-18, retain the immunomodulatory effects of the parent molecule and possess excellent potential as therapeutic agents in the treatment of oral infections including periodontal disease.

Immunocytochemical Localization of Substance P Receptors (NK-1 Receptors) in Human Gingival Tissue

Substance P (SP) is a member of the structurally related family of neuropeptides known as the tachykinins. In addition to neurotransmitter roles, the tachykinins are also known to modulate local inflammation which depends on signalling between the neuropeptide molecules and target cells and tissues. SP mediates its effects through a specific receptor, known as the substance P receptor or the neurokinin 1 (NK-1) receptor. The NK-1 receptor is a G-protein associated integral membrane protein and although it has been studied in a wide range of tissues, to date there has been no published data on the localisation of the NK-1 receptor in human gingival tissue. Objective: The aim of this study was to examine the distribution of the NK-1 receptor in human gingival tissue using immunocytochemistry. Method: Gingival tissue was obtained from patients undergoing periodontal surgery. Tissue was fixed in paraformaldehyde and embedded in wax for sectioning. Sections were dewaxed in xylene and then rehydrated in alcohols and phosphate buffered saline. Rehydrated sections were probed with rabbit polyclonal antibody to human NK-1 receptor which was subsequently detected using anti-rabbit horseradish peroxidase conjugate and diaminobenzidine as substrate. Results: Immunocytochemistry revealed that the NK-1 receptor was distributed along nerve fibres and blood vessel endothelial cells, suggesting these areas are main targets for the actions of SP via the NK-1 receptor. Conclusion: This is the first immunocytochemical report of NK-1 receptors in human gingival tissue and provides evidence for possible NK-1 mediated biological effects of SP in human gingival tissue from periodontitis patients.

Tratamiento de la recesión gingival mediante el injerto de tejido conectivo subepitelial (técnica de Langer y Langer) en pacientes con abfracciones, estudio longitudinal.

Tesis (Maestría en Ciencias Odontológicas con especialidad en Periodoncia) UANL, 2014.

The intelligibility of cleft palate speech with and without dental prosthesis

This paper discusses a study to investigate the possibility of quantifying and analyzing the speech of cleft palate subjects.

Invasive neural prosthesis for neural signal detection and nerve stimulation

This paper specifically examines the implantation of a microelectrode array into the median nerve of the left arm of a healthy male volunteer. The objective was to establish a bi-directional link between the human nervous system and a computer, via a unique interface module. This is the first time that such a device has been used with a healthy human. The aim of the study was to assess the efficacy, compatibility, and long term operability of the neural implant in allowing the subject to perceive feedback stimulation and for neural activity to be detected and processed such that the subject could interact with remote technologies. A case study demonstrating real-time control of an instrumented prosthetic hand by means of the bi-directional link is given. The implantation did not result in infection, and scanning electron microscope images of the implant post extraction have not indicated significant rejection of the implant by the body. No perceivable loss of hand sensation or motion control was experienced by the subject while the implant was in place, and further testing of the subject following the removal of the implant has not indicated any measurable long term defects. The implant was extracted after 96 days. Copyright © 2004 John Wiley & Sons, Ltd.

Prosthesis grasp reflex via peripheral nerve control: an in vitro study

Here we present an economical and versatile platform for developing motor control and sensory feedback of a prosthetic hand via in vitro mammalian peripheral nerve activity. In this study, closed-loop control of the grasp function of the prosthetic hand was achieved by stimulation of a peripheral nerve preparation in response to slip sensor data from a robotic hand, forming a rudimentary reflex action. The single degree of freedom grasp was triggered by single unit activity from motor and sensory fibers as a result of stimulation. The work presented here provides a novel, reproducible, economic, and robust platform for experimenting with neural control of prosthetic devices before attempting in vivo implementation.

An Alternative Section Method for Casting and Posterior Laser Welding of Metallic Frameworks for an Implant-Supported Prosthesis

Purpose: The aim of this study was to compare the accuracy of fit of three types of implant-supported frameworks cast in Ni-Cr alloy: specifically, a framework cast as one piece compared to frameworks cast separately in sections to the transverse or the diagonal axis, and later laser welded. Materials and Methods: Three sets of similar implant-supported frameworks were constructed. The first group of six 3-unit implant-supported frameworks were cast as one piece, the second group of six were sectioned in the transverse axis of the pontic region prior to casting, and the last group of six were sectioned in the diagonal axis of the pontic region prior to casting. The sectioned frameworks were positioned in the matrix (10 N(.)cm torque) and laser welded. To evaluate passive fit, readings were made with an optical microscope with both screws tightened and with only one-screw tightened. Data were submitted to ANOVA and Tukey-Kramer`s test (p < 0.05). Results: When both screws were tightened, no differences were found between the three groups (p > 0.05). In the single-screw-tightened test, with readings made opposite to the tightened side, the group cast as one piece (57.02 +/- 33.48 mu m) was significantly different (p < 0.05) from the group sectioned diagonally (18.92 +/- 4.75 mu m) but no different (p > 0.05) from the group transversally sectioned (31.42 +/- 20.68 mu m). On the tightened side, no significant differences were found between the groups (p > 0.05). Conclusions: Results of this study showed that casting diagonally sectioned frameworks lowers misfit levels of prosthetic implant-supported frameworks and also improves the levels of passivity to the same frameworks when compared to structures cast as one piece.

Antimicrobial Photodynamic Therapy in the Non-Surgical Treatment of Aggressive Periodontitis: Cytokine Profile in Gingival Crevicular Fluid, Preliminary Results

Background: Aggressive periodontitis is a specific form of periodontal disease that is characterized by rapid attachment loss and bone destruction. Cytokine profiles are of considerable value when studying disease course during treatment. The aim of this trial was to investigate cytokine levels in the gingival crevicular fluid (GCF) of patients with aggressive periodontitis, after treatment with photodynamic therapy (PDT) or scaling and root planing (SRP), in a split-mouth design on -7, 0, +1, +7, +30, and +90 days. Methods: Ten patients were randomly treated with PDT using a laser source associated with a photosensitizer or SRP with hand instruments. GCF samples were collected, and the concentrations of tumor necrosis factor-alpha (TNF-alpha) and receptor activator of nuclear factor-kappa B ligand (RANKL) were determined by enzyme-linked immunosorbent assays. The data were analyzed using generalized estimating equations to test the associations among treatments, evaluated parameters, and experimental times (alpha = 0.05). Results: Non-surgical periodontal treatment with PDT or SRP led to statistically significant reductions in TNF-alpha level 30 days following treatment. There were similar levels of TNF-alpha and RANKL at the different time points in both groups, with no statistically significant differences. Conclusion: SRP and PDT had similar effects on crevicular TNF-alpha and RANKL levels in patients with aggressive periodontitis. J Periodontol 2009;80:98-105.

Acellular Dermal Matrix Graft for Gingival Augmentation: A Preliminary Clinical, Histologic, and Ultrastructural Evaluation

Background: The aim of this study was to evaluate clinically, histologically, and ultrastructurally the integration process of the acellular dermal matrix used to increase the band of keratinized tissue while achieving gingival inflammation control. Methods: Ten patients exhibiting a mucogingival problem with bands of keratinized tissue <= 1 mm and gingival inflammation of the related teeth were included in the study. The surgical procedures were performed to augment the gingival tissue using acellular dermal matrix. Clinical measurements were assessed at baseline and after 3 months. A specimen of the allograft and surrounding tissues was obtained immediately before the surgery and 4 minutes and 1, 2, 3, 4, 6, and 10 weeks after grafting. Results: Clinically, a gain of keratinized tissue of 2.92 +/- 0.65 mm was observed after 3 months. Histologically and ultrastructurally, many macrophages were observed phagocytosing preexisting collagen fibers in the first weeks. From week 2 on, fibroblasts synthesizing new collagen, epithelial cells colonizing the graft surface, and revascularization were noticed. After 6 weeks it was difficult to find the acellular dermal matrix preexisting collagen fibers. This process of substitution was completed after 10 weeks, when the reepithelialization of the entire graft throughout a well-structured basement membrane was achieved. Conclusion: The acellular dermal matrix graft seemed to be an easily handled material for use in keratinized tissue augmentation that, in humans, was substituted and completely reepithelialized in 10 weeks according to histologic and ultrastructural results. J Periodontol 2009;80:253-259.

In Vitro Evaluation of Acellular Dermal Matrix as a Three-Dimensional Scaffold for Gingival Fibroblasts Seeding

Background: Tissue engineering principles could improve the incorporation of acellular dermal matrix (ADM). The aim of this study is to verify if ADM is a suitable three-dimensional matrix for gingival fibroblasts and cancerous cells ingrowth, and also if cultured medium conditioned in ADM affect cellular behavior. Methods: Canine gingival fibroblasts (CGF), human gingival fibroblasts (HGF), and murine melanoma cell line (B16F10) were seeded on ADM for up to 14 days. The following parameters were assessed: morphology and distribution of CGF, HGF, and B16F10; CGF and HGF viability; and the effect of ADM conditioned medium (CM) on CGF viability. Results: Epifluorescence revealed that CGF were unevenly distributed on the ADM surface, showing no increase in cell number over the periods of study; HGF formed a monolayer on the ADM surface in a higher number at 14 days (P<0.05); B16F10 exhibited an increase in cell number within 7 days (P<0.05), and were mainly arranged in cell aggregates on the ADM, forming a continuous layer at 14 days. A higher percentage of cells on the ADM surface (P<0.05) compared to inside was observed for all cell types. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MU) values indicated higher cell viability in samples cultured with HGF compared to CGF (P=0.024). A significantly lower cell viability for CGF grown in CM compared to cells grown in non-CM was observed at 48 and 72 hours (P<0.05). Conclusions: ADM is not suitable as a three-dimensional matrix for gingival fibroblasts ingrowth. Gingival fibroblasts and highly proliferative cells as B16F10 can only be superficially located on ADM, and CGF are negatively affected by culture medium conditioned in ADM, reducing its viability. J Periodontol 2011;82:293-301.

Myeloperoxidase activity is increased in gingival crevicular fluid and whole saliva after fixed orthodontic appliance activation

Introduction: Orthodontic tooth movement uses mechanical forces that result in inflammation in the first days. Myeloperoxidase (MPO) is an enzyme found in polymorphonuclear neutrophil (PMN) granules, and it is used to estimate the number of PMN granules in tissues. So far, MPO has not been used to study the inflammatory alterations after the application of orthodontic tooth movement forces. The aim of this study was to determine MPO activity in the gingival crevicular fluid (GCF) and saliva (whole stimulated saliva) of orthodontic patients at different time points after fixed appliance activation. Methods: MPO was determined in the GCF and collected by means of periopaper from the saliva of 14 patients with orthodontic fixed appliances. GCF and saliva samples were collected at baseline, 2 hours, and 7 and 14 days after application of the orthodontic force. Results: Mean MPO activity was increased in both the GCF and saliva of orthodontic patients at 2 hours after appliance activation (P<0.02 for all comparisons). At 2 hours, PMN infiltration into the periodontal ligament from the orthodontic force probably results in the increased MPO level observed at this time point. Conclusions: MPO might be a good marker to assess inflammation in orthodontic movement; it deserves further studies in orthodontic therapy. (Am J Orthod Dentofacial Orthop 2010;138:613-6)

Clinical and radiographic evaluation of a polyester prosthesis in dogs with cranial cruciate ligament rupture

Os achados clínicos e radiográficos após reparo intra-articular do ligamento cruzado cranial com prótese de poliéster, utilizando a técnica over-the-top modificada, foram avaliada em seis cães. Sete cirurgias foram realizadas devido ao acometimento bilateral em um dos animais. A avaliação clínica foi realizada ao 3º, 10º e 40º dias de pós-operatório, e a avaliação radiográfica realizada ao 5º e 24º meses após a cirurgia em cinco cães, por meio da qual se confirmou a progressão da doença articular degenerativa. A resolução dos sinais clínicos foi observada entre o 25º e 68º dias após a cirurgia, segundo avaliação realizada pelos proprietários. A função do membro operado foi considerada boa. Dois cães apresentaram desgaste e ruptura da prótese após a cirurgia. Concluiu-se que a prótese de poliéster, da forma como foi implantada neste estudo, não pode ser considerada como substituto satisfatório, uma vez que resultados superiores podem ser obtidos com ténicas menos invasivas e mais simples.

Genetic relatedness of commensal strains of Candida albicans carried in the oral cavity of patients' dental prosthesis users in Brazil

The aim of this study is to describe the degree of yeast-colonization in diabetic and hemodialysed-users of dental prostheses. Individuals (306) were examined using an oral rinse technique in order to evaluate the incidence of yeast-carriage, and genotype of C. albicans. Yeasts were isolated from 68.4% (91/133) individual's dental prostheses users. Dental prostheses were found to be a significant factor for the yeast colonization (P < 0.05). Overall, the intensity of carriage was higher in diabetic patients as compared with health and hemodialysed individuals (P < 0.05). The isolation rates were: C. albicans (51.7%), C. parapsilosis (20.9%), C. tropicalis (14.3%), C. glabrata (6.6%), C. krusei (3.3%), C. rugosa (1.1%), and Pichia (Pichia ohmeri, 2.2%). Ready-To-Go RAPD Analysis Beads were used and primer OPJ 6 distinguished the C. albicans isolates found in prostheses users. All the isolates were grouped into 11 RAPD profiles in four main clusters and, the average S (AB) for the entire collection of 47 C. albicans isolates were 0.779 +/- 0.178. Over 85% of isolates had a similarity level higher than or equal to 0.8 reinforcing the idea that the use of dental prostheses, independently of the host's clinical condition, probably provides the necessary conditions for these strains to gain a growth-specific advantage over others.