Experimental traumatic occlusion drives immune changes in trigeminal ganglion.

We previously demonstrated that experimental traumatic occlusion (ETO) induces a long-lasting nociceptive response. These findings were associated with altered neuronal patterns and suggestive satellite glial cell activation. This study aimed to elucidate the activation of satellite glial cells following ETO in the trigeminal ganglion. Moreover, we explored the involvement of resident and infiltrating cells in trigeminal ganglion in ETO. Finally, we investigated the overexpression of purinergic signaling and the CX3CL1/CX3CR1 axis. RT-qPCR and electrophoresis showed overexpression of GFAP in the trigeminal ganglion (TG), and immunohistochemistry corroborated these findings, demonstrating SGCs activation. ELISA reveals enhanced levels of TNF-α and IL-1ß in TG after 28 d of ETO. In trigeminal ganglia, ETO groups improved the release of CX3CL1, and immunohistochemistry showed higher CX3CR1+ -immunoreactive cells in ETO groups. Immunohistochemistry and electrophoresis of the P2X7 receptor were found in ETO groups. The mRNA levels of IBA1 are upregulated in the 0.7-mm ETO group, while immunohistochemistry showed higher IBA1+ -immunoreactive cells in both ETO groups. The expression of CD68 by electrophoresis and immunohistochemistry was observed in the ETO groups. For last, ELISA revealed increased levels of IL-6, IL-12, and CCL2 in the TG of ETO groups. Furthermore, the mRNA expression revealed augmented transcription factors and cytokines associated with lymphocyte activation, such as RORγt, IL-17, Tbet, IFNγ, FOXP3, and IL-10. The findings of this study suggested that ETO activates SGCs in TG, and purinergic signaling and CX3CL1/CX3CR1 axis were upregulated. We uncovered the involvement of a distinct subtype of macrophages, named sensory neuron-associated macrophage activation (sNMAs), and detected an expanded number of infiltrated macrophages onto TG. These findings indicate that ETO induces chronic/persistent immune response.

Occlusion Heightened by Metal Crown Cementation is Aggressive for Periodontal Tissues.

PURPOSE: To investigate the effect of experimental traumatic occlusion (ETO) induced by metal crowns on alveolar bone loss. MATERIALS AND METHODS: Metal crowns were custom-made for the lower first molars with occlusal discrepancy of 0.4 and 0.7 mm from the maximum intercuspation. Thirty-six animals were randomly divided into three groups (n = 12 animals per group): 0.4-mm hyperocclusion group, 0.7-mm hyperocclusion group and the sham group (no metal crown). Twenty-eight days after crown cementation, the animals were euthanized and gingival tissue was collected to assess cytokine levels of IL-17, IL-6, and TNF-α using enzyme-linked immunosorbent assay (ELISA). Mandibles were stained with 1% methylene blue and alveolar bone levels were quantified. Western blotting was used to quantify the expression of receptor activator of nuclear factor κ B (RANK), and its ligand (RANKL), secreted osteoclastogenic factor of activated T cells (SOFAT) and TNF-α-converting enzyme (TACE). Also, mandibles were histologically processed and stained with hematoxylin and eosin, from which the presence of osteoclast-like cells, multinucleated cells containing ≥3 nuclei was counted at 100× magnification. The data were analyzed using one-way ANOVA and Tukey tests. RESULTS: Experimental occlusal trauma for 28 consecutive days significantly increased alveolar bone loss and multinucleated cell counts (p < 0.05). RANK, RANKL, SOFAT, TACE, IL-6, and TNF-α were significantly higher in gingival tissues of ETO groups (p < 0.05). IL-17 titers were unchanged among the groups (p > 0.05). CONCLUSION: Experimental traumatic occlusion activates and sustains bone resorption pathways in the periodontium inducing alveolar bone resorption. As the intensity of occlusal trauma increased, alternative osteoclastic pathways were activated, such as TACE and SOFAT.

Metallic crown-induced occlusal trauma as a protocol to evaluate inflammatory response in temporomandibular joint and periodontal tissues of rats.

OBJECTIVES: The goal of this study is to propose a standard protocol of experimental occlusal trauma to evaluate the inflammatory hyperalgesia induced by metallic crowns on orofacial tissues of rats. MATERIALS AND METHODS: Thirty animals were randomly divided into six groups (n = 5 per group). Detailed methodology on the manufacturing of metallic crowns is described. The inflammatory hyperalgesia induced by occlusal interference was evaluated by intra-articular injection of a low dose of 0.5% formalin (30 µl) or vehicle (saline) into temporomandibular joint, 21 or 28 days after metallic crown cementation. Posteriorly, pro-inflammatory cytokines were evaluated by enzyme-linked immunosorbent assay to assess the effect of occlusal interference on periodontium. RESULTS: The cementation of metallic crowns with dental anatomy on the lower molar of rats does not show signs of stress and lack of feeding. Metallic crown-induced occlusal trauma results in a temporomandibular joint inflammatory hyperalgesia (P < 0.05: ANOVA, Tukey's test). Otherwise, it was observed that occlusal trauma results in the increase of protein level of pro-inflammatory cytokines TNF-alpha and IL-1beta in the gingival tissues (P < 0.05). CONCLUSION: This study demonstrates in detail a methodology of occlusal trauma resulting from the cementation of metallic crowns in the lower molars of rats, mimicking occlusal interferences commonly evaluated in the dental clinic. This methodology makes new studies to better understand the mechanisms involved in the occlusal trauma of orofacial tissues possible. CLINICAL RELEVANCE: The standardization of an experimental occlusal interference model will allow us to understand the deleterious effect and mechanisms that affect the orofacial tissues.

Fracture Strength of Aged Monolithic and Bilayer Zirconia-Based Crowns.

The purpose of this study was to evaluate the effect of design and surface finishing on fracture strength of yttria-tetragonal zirconia polycrystal (Y-TZP) crowns in monolithic (1.5 mm thickness) and bilayer (0.8 mm zirconia coping and 0.7 mm porcelain veneer) configuration after artificial aging. Bovine incisors received crown preparation and Y-TZP crowns were manufactured using CAD/CAM technique, according to the following groups (n = 10): Polished monolithic zirconia crowns (PM); Glazed monolithic zirconia crowns (GM); Bi-layer crowns (BL). Crowns were cemented with resin cement, submitted to artificial aging in a chewing simulator (2.5 million cycles/80 N/artificial saliva/37 °C), and tested for fracture strength. Two remaining crowns referring to PM and GM groups were submitted to a chemical composition analysis to measure the level of yttrium after aging. One-way ANOVA and Tukey's test (P = .05) indicated that monolithic zirconia crowns presented similar fracture strength (PM = 3476.2 N ± 791.7; GM = 3561.5 N ± 991.6), which was higher than bilayer crowns (2060.4 N ± 810.6). There was no difference in the yttrium content among the three surfaces evaluated in the monolithic crowns. Thus, monolithic zirconia crowns present higher fracture strength than bilayer veneered zirconia after artificial aging and surface finishing does not affect their fracture strength.

Reestablishment of the condyle-fossa and maxillomandibular relationships using a flat occlusal plane splint and implant-supported denture: case report with a 2-year follow-up / Restabelecimento das relações côndilo-fossa e maxilo-mandibular por meio de aparelho oclusal plano e próteses totais fixas implantossuportadas: relato de caso clínico com 2 anos de acompanhamento

When the shape, structure, and/or function of one of the parts of the components of the stomatognathic system change, structural and physiological changes also occur to absorb or compensate the consequent loads. Hence, an insightful rehabilitation of this type of patient involves essential procedures, such as: correct orientation of the occlusal plane, determination of the vertical dimension of occlusion, and a stable and healthy maxillomandibular relationship, since the nonobservance of these aspects may result in prosthodontic rehabilitation failure. The objective of the present case study is to report the preoperative planning and prosthodontic rehabilitation of an edentulous patient with severe maxillary atrophy and signs and symptoms of temporomandibular disorders. The patient underwent flat occlusal plane splint therapy to reestablish the condyle-fossa and maxillomandibular relationships and muscle activity, followed by prosthodontic rehabilitation with implant-supported complete dentures. The maxillomandibular relationship was determined by the intraoral tracing technique, with a 24-month follow-up.

Quando os componentes do sistema estomatognático sofrem alterações na forma, estrutura e/ou função de uma das partes, também ocorrem modificações estruturais e fisiológicas para a absorção ou compensação das resultantes criadas. Assim, uma criteriosa reabilitação deste tipo de paciente envolve procedimentos fundamentais, como: correta orientação do plano oclusal, determinação da dimensão vertical de oclusão adequada e a relação maxilo-mandibular estável e saudável, sendo que a não observação destes aspectos pode levar ao fracasso da reabilitação protética. O objetivo do presente caso é relatar o planejamento pré-cirúrgico e a reabilitação protética de um paciente edêntulo com atrofia severa dos maxilares e sinais e sintomas de Desordens Temporomandibulares, que foi submetido à terapia com aparelhos oclusais planos e lisos para restabelecimento das relações côndilo-fossa, maxilo-mandibular e da atividade muscular e, posterior reabilitação oral com próteses totais fixas implantossuportadas,onde a determinação da relação maxilo-mandibular foi realizada pela técnica do registro intraoral, com um período de proservação de 24 meses.

Relação entre dimensão vertical de oclusão e postura da cabeça e pescoço: relato de caso clínico com controle de 24 meses / Relationship between occlusal vertical dimention and position of the head and neck: clinical relate with 24 moths fallow-up

A desordem temporomandibular (DTM) é considerada uma síndrome pela diversidade de sinais e sintomas a ela associados. O sucesso do seu tratamento depende dentre outros fatores, do conhecimento profundo dos profissionais de várias áreas médicas e odontológicas, sendo a sua interelação imprescindível. Este trabalho tem como objetivo relatar por meio de um caso clínico, a remissão da sintomatologia dolorosa relacionada a esta patologia e da região cervical e, a alteração da postura da cabeça e pescoço; obtida com o tratamento odontológico reabilitador, recuperação da tonicidade muscular, otimização da posição mandibular e restituição da relação maxilo-mandibular com aparelho oclusal plano, com um período de proservação de 24 meses; em um paciente do gênero masculino, na Clínica do Curso de Especialização em Prótese Dental da Faculdade de Odontologia de Piracicaba - UNICAMP.

The temporomandibular joint dysfunction symdrome (TMJDS) is considered a syndrome due the diversity of signs and symptoms associeted. The success of its treatment depends amongst other factors, on the professional's knowledge regarding its medial and dental aspects. The case report describes the remission of paintful symptomatology on the cervical region and the cervical region and the alteration of the position of the head and neck obtained after prosthetic treatment, recovery of the muscular tonus, optimization of the mandibular position and establishment occlusal vertical dimension. The male patient was treated at the Dental Clinic of the Specialization Course of Prosthetic Dentistry at Piracicaba Dental College-UNICAMP.

Assessment of painful symptomology in patients with temporomandibular disorders by means of a combined experimental scale

Quantification and assessment of the evolution of painful symptomology in patients with temporomandibular disorders, during the pre-, trans- and post-therapeutic stages is one of the greatest difficulties found by dental surgeons. Various authors have studied and discussed the use of verbal and non-verbal scales for this purpose. Therefore, this study aimed, by means of a combined experimental scale, to assess the evolution of painful symptomology in patients with completely edentulous maxilla and partly edentulous mandible, with Class I or Class II Kennedy prosthetic spaces, treated with flat occlusal appliances, before, during and after 150 of starting treatment. A selection was made of 16 patients with a mean age of fifty-two years, with signs and symptoms of temporomandibular disorders and diminished vertical occlusion dimension. The patients were submitted to treatment with flat occlusal appliances and fortnightly consultations for a period of 150 days. During these consultations, patients recorded their painful symptomology on a combined experimental pain scale. The results obtained were grouped into tables and submitted to the Friedman Test at a level of 5% probability. These revealed statistically significant differences between the values obtained at each assessment made. According to the methodology used and the results obtained, it was concluded that the therapy used was effective and that the experimental scale was efficient for registering the evolution of the symptoms initially detected.