CCR5 Mediates Pro-osteoclastic and Osteoclastogenic Leukocyte Chemoattraction

Periodontal disease (PD) progression involves the selective leukocyte infiltration into periodontium, supposedly mediated by the chemokine/chemokine receptor system. In this study, we investigated the role of chemokine receptor CCR5 in the immunoregulation of experimental PD in C57BL/6 (WT) and CCR5KO mice. Aggregatibacter actinomycetem comitans infection triggered the chemoattraction of distinct CCR5+ leukocyte subpopulations (determined by flow cytometry): CCR5+F4/80+ leukocytes, which co-express CD14, CCR2, TNF-alpha, and IL-1 beta, indicative of activated macrophages; and CCR5+CD4+ cells, which co-express CXCR3, IFN-gamma, and RANKL, indicative of Th1 lymphocytes, therefore comprising pro-osteoclastic and osteoclastogenic cell subsets, respectively. CCR5KO mice presented a lower PD severity (lower inflammation and alveolar bone loss) when compared with the WT strain, since the migration of F4/80+, TNF-alpha+, CD4+, and RANKL+ cells specifically decreased due to the lack of CCR5. Also, ELISA analysis demonstrated that the production of TNF-alpha, IL-1 beta, IL-6, IFN-gamma, and RANKL in periodontal tissues was significantly decreased in the CCR5KO strain. The periodontal bacterial load and antimicrobial patterns were unaltered in CCR5KO mice. Our results demonstrate that the chemokine receptor is involved in the migration of distinct leukocyte subpopulations throughout experimental PD, being a potential target for therapeutic intervention in PD.

Cytotoxicity of titanium and titanium alloying elements

It is commonly accepted that titanium and the titanium alloying elements of tantalum, niobium, zirconium, molybdenum, tin, and silicon are biocompatible. However, our research in the development of new titanium alloys for biomedical applications indicated that some titanium alloys containing molybdenum, niobium, and silicon produced by powder metallurgy show a certain degree of cytotoxicity. We hypothesized that the cytotoxicity is linked to the ion release from the metals. To prove this hypothesis, we assessed the cytotoxicity of titanium and titanium alloying elements in both forms of powder and bulk, using osteoblast-like SaOS₂ cells. Results indicated that the metal powders of titanium, niobium, molybdenum, and silicon are cytotoxic, and the bulk metals of silicon and molybdenum also showed cytotoxicity. Meanwhile, we established that the safe ion concentrations (below which the ion concentration is non-toxic) are 8.5, 15.5, 172.0, and 37,000.0 μg/L for molybdenum, titanium, niobium, and silicon, respectively.

Bioética e odontologia: um perfil dos problemas éticos vividos por cirurgiões-dentistas

Bioethics studies human behavior in the fields ofbiological sciences and health care. Tt strives for humanization in health services along with promoting the rights of patients. In view of the lack of dental research dealing with this topic, the present study was undertaken to identify, from the viewpoint of dental surgeons, ethical problems experienced in dental practice,understand how they occur and how professionals deal with them. It is a descriptive exploratory investigation within a qualitative approach. Empirical material was collected through semi-structured interviews performed with 15 dental surgeons who work both in private and public practice in the state of Rio Grande do Norte, Brazil. The content of the interviews was systemized and organized, resulting in the identification of topics, from which were grouped the ethical problems reported by the participants. The resu1ts indicate that many of the ethical problems coincide with infringements of the norms and mIes of the Dental Code of Ethics, confirming a dental ethic acquired during professional formation and therefore, inadequate for solving the problems that emerge in professional practice. Other questions stand out such as low salaries, competition and poor working conditions. Associated to these problems are lack of commitment and professional responsibility with the patients. Concem with maintaining user autonomy, guaranteeing access to specialized services, and the need for performing only procedures for which they are technically qualified arise in the responses, leading to difficulties in consolidating the principIes proclaimed by bioethics: autonomy, justice, nonmaleficence and beneficence. We concluded that the ethical problems identified in professional practice need to be understood beyond the dental dimension, towards a human approach. It is therefore necessary to incorporate health care management technologies into health practices, including dentistry, which implies recognizing the difTerent dimensions that surround individuaIs, that is, social, economic, political and cultural

Origin of sensory and autonomic innervation of the rat temporomandibular joint: A retrograde axonal tracing study with the fluorescent dye fast blue

Previous studies that have used retrograde axonal tracers (horseradish peroxidase alone or conjugated with wheat germ agglutinin) have shown that the temporomandibular joint (TMJ) is supplied with nerve fibers originating mainly from the trigeminal ganglion, in addition to other sensory and sympathetic ganglia. The existence of nerve fibers in the TMJ originating from the trigeminal mesencephalic nucleus is unclear, and the possible innervation by parasympathetic nerve fibers has not been determined. In the present work, the retrograde axonal tracer, fast blue, was used to elucidate these questions and re-evaluated the literature data. The tracer was deposited in the supradiscal articular space of the rat TMJ, and an extensive morphometric analysis was performed of the labeled perikaryal profiles located in sensory and autonomic ganglia. This methodology permitted us to observe labeled small perikaryal profiles in the trigeminal ganglion, clustered mainly in the posterior-lateral region of the dorsal, medial and ventral thirds of horizontal sections, with some located in the anterior-lateral region of the ventral third. Sensory perikarya were also labeled in the dorsal root ganglia from C2 to C5. No labeled perikaryal profiles were found in the trigeminal mesencephalic nucleus. on the other hand, autonomic labeled perikaryal profiles were distributed in the sympathetic superior cervical and stellate ganglia, and parasympathetic otic ganglion. Our results confirmed those of previous studies and also demonstrated that: (i) there is a distribution pattern of labeled perikaryal profiles in the trigeminal ganglion; (ii) some perikaryal profiles located in the otic ganglion were labeled; and (iii) the trigeminal mesencephalic nucleus did not show any retrogradely labeled perikaryal profiles.

PAR(2) and Temporomandibular Joint Inflammation in the Rat

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dentists' level of knowledge of the treatment plans for periodontal ligament injuries after dentoalveolar trauma

This study investigated the level of knowledge held by dentists about the possible treatment plan procedures for periodontal ligament injuries after dentoalveolar trauma. A 5-item self-applied questionnaire was prepared with questions referring to the professional profile of the interviewees and to the treatment plan they would propose for periodontal ligament injuries secondary to dentoalveolar trauma. The questionnaires were filled out by 693 dentists attending the 23rd Annual Meeting of the Brazilian Society for Dental Research, and the data obtained were subjected to descriptive analysis. Either the chi-square test or Fisher's exact test was applied to assess associations among variables, at a 5% level of significance. The results revealed that dentists experienced difficulty in establishing a treatment plan for subluxation, and for extrusive, lateral and intrusive luxations. In general, holding a dental specialty degree had no influence on the knowledge about treatment plan procedures for the most severe injuries. It could be concluded that the dentists participating in this study, whether specialists or not, did not have sufficient knowledge to treat most of the periodontal ligament injuries resulting from dentoalveolar trauma adequately.

Evaluation of Satisfaction of Patients Rehabilitated With Zygomatic Fixtures

Purpose: The aim of this study was to evaluate the satisfaction of patients rehabilitated with zygomatic fixtures and prosthesis with immediate loading.Materials and Methods: The study selected patients who were rehabilitated with zygomatic implants at the clinic of the Latin American Institute for Dental Research and Education (ILAPEO. Curitiba-PR. Brasil) between 2005 and 2009. The patients were asked to answer a control-questionnaire during their follow-up visits. Data were collected regarding the level of patient satisfaction, reason for dissatisfaction, number of post-operative clinical sessions, and the type of complication. Sixteen patients were selected: 10 females and 6 males.Results: Half of the patients were completely satisfied while the other half were satisfied with some complaints. The complaints were related to hygiene, esthetics, phonetics, and discomfort during chewing. Regarding the post-operative evaluation, 50% of the patients were attended due to the prosthesis (62.5%) and the implant (37.5%).Conclusions: The treatment with zygomatic fixtures is predictable and reliable. The patients were satisfied both with implants and prosthesis. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70: 314-319, 2012