Nociceptive and histomorphometric evaluation of the effects of ozone therapy on the rat masseter muscle in a carrageenan model of myofascial pain.

OBJECTIVE: This study evaluated the effects of intramuscular ozone therapy on nociception, inflammation, and tissue damage caused by the injection of carrageenan in the masseter muscle of rats. DESIGN: Rat masseter muscles were injected with saline or carrageenan. Seventy-seven adult male rats were divided into six groups: Sal, saline; Car, carrageenan; Ibup + Sal, ibuprofen and saline; Ibup + Car, ibuprofen and carrageenan; O3 + Sal, ozone and saline; and O3 + Car, ozone and carrageenan. The mixture of 5% ozone and 95% oxygen (20 µg/mL) was administered three times in the course of a week. Nociceptive responses in the masseter muscles were measured using a head withdrawal threshold, determined by an electronic von Frey anesthesiometer. The animals were euthanized one or eight days after the carrageenan injection, and the masseters were submitted to histological and histomorphometric analyses. RESULTS: Mechanical allodynia and inflammation levels were reduced in the Ibup + Car group compared to the other groups. Myonecrosis was similar among carrageenan-treated groups. Picrosirius red stained sections showed more collagen fibers and more regenerating myofibers in the O3 + Car group compared to the other groups. Eight days after carrageenan injection, the O3 + Car group showed neutrophils close to the regenerating myofibers. CONCLUSIONS: Intramuscular ozone therapy did not alleviate mechanical allodynia, and it did not protect the masseter muscle against the deleterious effects produced by carrageenan, probably due to the mode of administration of this therapeutic agent.

O modelo de dor inflamatória induzida pela carragenina como estratégia para avaliar a ação de drogas sobre a dor miofascial / The carrageenan-induced inflammatory pain model as a tool to assess the action of drugs on myofascial pain

A dor miofascial orofacial vem sendo tratada com analgésicos, anti-inflamatórios, relaxantes musculares, fisioterapia, laserterapia e placas oclusais. Contudo, muitas vezes, tais condutas falham em amenizar o quadro doloroso, havendo a necessidade de testar outras estratégias de tratamento. Metodologia: Uma opção para avaliação experimental dessas terapias seria o teste de dor induzido pela carragenina, associado ao teste de avaliação do limiar nociceptivo, originalmente desenvolvido para avaliar a ação de drogas nas patas de roedores. Sendo assim, o presente estudo analisou a nocicepção causada pela carragenina em masseteres de ratos, através do teste de Von Frey, correlacionando-a com alterações teciduais produzidas por esta droga. A carragenina foi injetada no músculo masseter de ratos, enquanto o grupo controle recebeu soro fisiológico. O limiar nociceptivo foi mensurado com um analgesímetro digital antes da administração da carragenina e 5 horas, 1, 3 e 7 dias após o seu uso. Decorridos 8 dias da intervenção, os animais foram eutanasiados, sendo seus masseteres encaminhados para processamento histológico e coloração H&E. Resultados: Observou-se uma diminuição do limiar da resposta nociceptiva em todos os períodos no grupo com carragenina, quando comparado com o grupo controle, havendo diferença estatisticamente significante nas 5 horas. A análise histológica do grupo experimental mostrou a presença de espaços perimisial e endomisial alargados e preenchidos por uma matriz com alguns linfócitos, muitos macrófagos e raros mastócitos. Conclusão: Os resultados indicaram que a associação de uma droga inflamatória com o método Von Frey pode ser uma opção para o estudo do efeito de terapias de dor miofascial.

Myofascial orofacial pain has been treated with analgesics, anti-inflammatories, muscle relaxants, physiotherapy, laser therapy and occlusal plaques. However, many times, such behaviors fail to alleviate the painful condition, with the need to test other treatment strategies. Methodology: An option for experimental evaluation of these therapies would be the pain test induced by carrageenan associated with the nociceptive threshold assessment test, originally developed to assess the action of drugs on the rodents' feet. Thus, the present study analyzed the nociception caused by carrageenan in rat masseter using the Von Frey test, correlating it with tissue changes produced by this drug. Carrageenan was injected into the masseter muscle of rats, while the control group received saline. The nociceptive threshold was measured with a digital analgesometer before administration of carrageenan and 5 hours, 1, 3 and 7 days after its use. After 8 days of the intervention, the animals were euthanized, and their masseters were sent for histological processing and H&E staining. Results: There was a decrease in the nociceptive response threshold in all periods in the group treated with carrageenan when compared to the control group, with a statistically significant difference at 5 hours. Histological analysis of the experimental group showed the presence of enlarged perimisial and endomisial spaces, filled by a matrix with some lymphocytes, many macrophages and rare mast cells. Conclusion: Results indicated that the association of an inflammatory drug with the Von Frey method may be an option for studying the effect of therapies on myofascial pain.

Estudo morfológico do efeito do trauma mecânico sobre a amelogênese em incisivos de ratos / Morphological study of the effect of mechanical trauma on amelogenesis in rat incisors

Introdução: a amelogênese compreende a formação do esmalte por células especializadas denominadas ameloblastos. Os ameloblastos secretam proteínas da matriz e são responsáveis pela criação de um ambiente extracelular que favorece a mineralização do esmalte. Contudo, diversos fatores, como o trauma dentário, podem interferir na amelogênese, contribuindo para a formação de um esmalte defeituoso. O trauma dentário tem sido responsável por muitos casos de hipoplasia que podem fragilizar o dente, além de trazer desconforto estético. Objetivo: examinar as alterações morfológicas sobre o epitélio odontogênico e a matriz de esmalte de incisivos de ratos, produzidas por um trauma dentário. Metodologia: incisivos de ratos foram extruídos e depois reposicionados em seus alvéolos originais. Decorridos 3, 7, 10, 20, 30 e 60 dias do procedimento cirúrgico, os dentes foram fixados em uma solução de formaldeído e glutaraldeído, processados histologicamente e corados com azul de toluidina. Resultados: a análise morfológica revelou a formação de uma matriz de esmalte bastante heterogênea, com espessura irregular, particularmente na porção mais apical dos incisivos. Algumas matrizes de esmalte expostas mostravam pequenas lacunas de reabsorção, muitas vezes com deposição de um material cementoide. Conclusão: o presente estudo mostrou que o trauma foi suficiente para produzir alterações hipoplásicas e de hipomineralização importantes no esmalte que se relacionaram com a fase funcional dos ameloblastos na região afetada.

Introduction: amelogenesis comprises of enamel formation by specialized cells called ameloblasts. Ameloblasts secrete matrix proteins and are responsible for the creation of an extracellular environment that favors the enamel mineralization. However, various factors, such as the dental trauma, can interfere with amelogenesis, contributing to the formation of a defective enamel. Dental trauma has been responsible for many cases of hypoplasia which can weaken the tooth, in addition to bringing aesthetic discomfort. Objective: examine the morphological changes on the odontogenic epithelium and the enamel matrix of rats incisors, produced by dental trauma. Methodology: rats incisors were extruded and then repositioned in their original alveoli. After 3, 7, 10, 20, 30 and 60 days of the surgical procedure, teeth were fixed in a solution of formaldehyde and glutaraldehyde, processed histologically and stained with toluidine blue. Results: the morphological analysis revealed the formation of enamel matrix extremely heterogeneous, with irregular thickness, particularly on the apical portion of the incisors. Some matrixes of exposed enamel showed small gaps of reabsorption, often with deposition of cementoid material. Conclusion: the present study showed that the trauma was enough to produce hypoplastic and hypomineralization changes important in the enamel that were related to the functional phase of the ameloblasts in the affected region

Effect of low-level laser therapy (λ780 nm) on the mechanically damaged dentin-pulp complex in a model of extrusive luxation in rat incisors.

In order to regenerate the dental pulp, many strategies have been developed as phototherapy. In the pulp repair, we do not know if gallium-aluminum-arsenide (GaAlAs) laser preserves the primary odontoblasts or stimulates the formation of more dentin matrix when dental pulp is damaged. The aim of the present study was to examine the effect of laser phototherapy (λ780 nm) on vascularization, inflammation, density of the primary odontoblast layer, and formation of reactionary and reparative dentin in the dental pulp by provoking extrusion of the rat incisor. The upper incisors were extruded 3 mm and then repositioned into their original sockets followed by a laser irradiation of the palatal mucosa (λ = 780 nm; p = 70 mW; CW; 4.2 J/cm2; 60 s) every 48 h. Non-traumatized and/or non-irradiated incisors were used as the controls. At 8 and 30 days after surgery, incisors were processed for histological and histomorphometric analysis. Morphological analysis revealed no differences in vascularization between groups, but showed discrete inflammation in some non-irradiated and injured specimens, which correlated with a more irregular reparative dentin. The density of primary odontoblasts in the groups treated with lasers was higher when compared to non-irradiated groups, but no statistically significant difference between groups (p > 0.05). The thickness of the tertiary dentin was increased in both traumatized groups with no statistically significant difference between non-irradiated and irradiated groups (p > 0.05).The present findings revealed that the GaAlAs laser induced small changes on dentin-pulp complex, with more regular dentin matrix in the irradiated dental pulps.

A comparative study of the effects of two carbamide peroxide bleaching agents on the structure of enamel / Estudo comparativo do efeito de dois agentes clareadores à base de peróxido de carbamida sobre a estrutura do esmalte

ABSTRACT Objective: Considering that different sources of carbamide peroxide bleaching agent may cause greater or lesser damage to the enamel and may have reduced effectiveness in dental whitening, the aim of this study was to compare the effects on the structure of enamel of two bleaching agents, drugstore-compounded and commercial carbamide peroxide bleaching agents. Methods: The specimens in the first group (drugstore-compounded carbamide peroxide) and second group (commercial carbamide peroxide) were treated with to 16% carbamide peroxide for 4 h per day for 20 days. The third group served as a control and was kept in artificial saliva during the test period. After the treatments, all specimens were examined via scanning electron microscopy. Results: Changes in the enamel morphology were similar in both experimental groups, but these changes were greater than those observed in the control group. The changes were mild and included only pores. Conclusion: There were no differences regarding damage to the enamel between drugstore-compounded and commercial carbamide peroxide bleaching agents.

RESUMO Objetivo: Comparar por microscopia eletrônica de varredura, os efeitos sobre a superfície do esmalte de um agente clareador à base de peróxido de carbamida comercial e outro preparado em farmácia de manipulação. Métodos: Os espécimes do primeiro grupo (confeccionado em farmácias de manipulação) e do segundo grupo (peróxido de carbamida comercial) foram tratados com peróxido de carbamida a 16% por 4 horas durante 20 dias. O terceiro grupo (controle) foi preservado em saliva artificial durante todo o experimento. Após os tratamentos, todas as amostras foram examinadas por microscopia eletrônica de transmissão. Resultados: As alterações foram sutis e compreenderam apenas poros. As alterações na morfologia do esmalte nos grupos experimentais foram similares, mas foram maiores do que aquelas observadas no grupo controle. Conclusão: Não foram observadas diferenças na superfície do esmalte dentário entre os agentes clareadores à base de peróxido de carbamida comerciais e aqueles adquiridos em farmácias de manipulação.

Evaluation of laser phototherapy (λ 780 nm) after dental replantation in rats.

BACKGROUND/AIM: Tooth replantation is the treatment of choice in cases of avulsion although the outcomes are variable. The teeth can be lost due to external root resorption. The aim of this study was to histologically assess of the effect of laser phototherapy (λ780 nm) on replanted teeth in rats. MATERIAL AND METHODS: Sixty Wistar Albinus rats had their maxillary right incisors extracted and were then divided into four groups: G1-absence of storage medium; G2-milk as storage medium; G3-milk as storage medium followed by a laser irradiation of the root surfaces and entrance of the alveolus (λ = 780 nm; P = 70 mW; CW; DE = 21 J/cm2 ); G4-milk as storage medium, laser irradiation as in G3 before replantation. After this procedure, laser irradiation was performed on the buccal and palatal mucosa (8.4 J/cm2 per session) every 48 h for 15 days. The animals were euthanized 15, 30, and 60 days after replantation. RESULTS: The histological results showed that after 15 days, G4 exhibited intense chronic inflammation with the presence of clastic cells and moderate external inflammatory root resorption (P < 0.05) when compared with G3, in which these outcomes were not observed. At the 30th day, G1, G2, and G4 showed chronic inflammation varying from discrete to moderate, as well as intense external inflammatory root resorption. G3 remained without any inflammation and external inflammatory root resorption up to the 60th day. CONCLUSIONS: The use of laser phototherapy on the root surface and at the entrance of the alveolus prior to replantation had a positive biomodulative effect on alveolar repair after tooth replantation in rats.

Prevalence of orofacial alterations in sickle cell disease: a review of literature

AIM: To evaluate the manifestations of sickle cell disease on the orofacial complex through a review of current literature concerning prevalence of dental caries, periodontal disease, temporomandibular joint disorders and radiographic alterations of maxillofacial bones. METHODS: Full-text papers retrieved from MEDLINE and LILACS electronic databases were critically reviewed. RESULTS: Alterations of maxillofacial bones are well documented in the literature, but studies reporting caries, periodontal condition and temporomandibular joint alterations in are scarce and inconclusive. CONCLUSION: Further well-designed epidemiological studies are needed to indicate the real impact of this disease on the stomatognathic health, collaborating to improve public health policies.

Sickle cell disease does not predispose to caries or periodontal disease.

This study investigated the prevalence of dental caries and periodontal condition in a population with sickle cell disease (SCD), analyzing some associations with disease severity. The Decayed, Missing and Filled Teeth index (DMFT) and Community Periodontal Index (CPI) were recorded for 99 individuals with SCD and 91 matched controls. Socio-demographic status, oral health behaviors, and history of clinical severity of SCD were assessed. Statistical comparisons were performed between the group with SCD and the control group, as well as multivariate logistic regression analyses with DMFT index and CPI as the dependent variables. The mean number of decayed teeth was significantly higher in individuals with HbSS. Older age, female gender, and daily smoking were identified as risk factors for higher DMFT, while older age and absence of daily use of dental floss were risk factors for the development of periodontal disease. In conclusion, risk factors known to cause caries and periodontal disease had more influence on oral health than the direct impact of SCD.

Immunocytochemical detection of dentine matrix protein 1 in experimentally induced reactionary and reparative dentine in rat incisors.

OBJECTIVE: Although the general mechanisms of dentinogenesis are understood, several aspects regarding tertiary dentine formation still deserve investigation, especially regarding the presence and distribution of some noncollagenous matrix proteins. As dentine matrix protein 1 (DMP 1) is present in primary dentine, it is possible that this protein may also be present in the dentine matrix secreted after injury, but there are no immunocytochemical studies attempting its detection in tertiary dentine. The aim of this study was to examine the ultrastructural immunolocalization of DMP 1 in the tertiary dentine after extrusion of the rat incisor. STUDY DESIGN: Upper incisors were extruded 3mm and then repositioned into their sockets. After several periods, the incisors were fixed and processed for transmission electron microscopy and for immunocytochemistry for DMP 1. RESULTS: Extrusion yielded both types of tertiary dentine, which varied in aspect and related cells. DMP 1 was found in the mineralized matrix of all types of dentine, presenting high affinity for collagen, but rare colloidal gold particles over predentine. DMP 1 was evident in the supranuclear region and inside the nucleus of some odontoblast-like cells. CONCLUSION: The observed association between DMP 1 and collagen seem to be essential for reactionary and reparative dentine formation.

Parotid gland with double duct: an anatomic variation description / Glándula parótida con doble conducto: descripción de una variación anatómica

The parotid is the largest salivary gland in humans producing an essentially serous secretion, which normally reaches the oral cavity through a sole duct (the parotid duct) after the latter making its way through the buccinator muscle to reach the mucosa lining the mouth at the level of the cheek. The present study reports on a rare case of double parotid duct found during the dissection the right side of the face of a cadaver of a 46-year-old male individual. The superior (Dl) and inferior (D2) ducts were 26.49 mm and 37.25 mm long, respectively. Based on the diameter of both ducts (Dl and D2) taken in the posterior (3.05 mm and 2.84 mm, respectively) and mid (2.84 mm and 2.68 mm, respectively) thirds, as well as on the histological findings, both ducts were considered to be main parotid ducts. These two ducts merged at the level of the anterior third forming one sole opening into the oral cavity. The data hereby reported are relevant to the various clinical and surgical procedures involving the parotid gland.

La parótida es la glándula salival más grande presente en el hombre y su producto de secreción, básicamente seroso, es normalmente dirigido hasta la cavidad oral, a través de un único canal parotídeo que, luego de perforar el músculo buccinador, desemboca en la mucosa de la mejilla. Este trabajo muestra un caso raro de doble canal parotídeo hallado durante la diseccción de un cadáver de sexo masculino, de 46 años de edad, en el lado derecho del rostro. Los canales superior (DI) e inferior (D2), presentaron una longitud de 26,49 mm y 37,25 mm, respectivamente. En base a los diámetros presentados por los canales en los tercios posterior (DI 3,05mm; D2 2,84 mm) y medio (DI 2,84mm; D2 2,68 mm) y de acuerdo con los hallazgos histológicos, ambos fueron considerados principales. En el tercio más anterior los canales se fusionaron, presentando una única apertura en la cavidad oral. Las informaciones presentadas en este documento son relevantes para diferentes procedimientos clínicos y quirúrgicos que tengan relación con la glándula parótida.

Ultrastructural and immunocytochemical analyses of osteopontin in reactionary and reparative dentine formed after extrusion of upper rat incisors.

Reactionary dentine and reparative dentine are two strategies used by the dentine-pulp complex to respond to injury. The reactionary dentine is secreted by original odontoblasts, while the reparative dentine is formed by odontoblast-like cells. Osteopontin (OPN) is a non-collagenous protein usually present in the repair of mineralized tissues. It is likely to be present in newly formed dentine but there are no studies attempting to detect it in reactionary and reparative dentine. The aim of the present study was to examine the ultrastructural characteristics, as well as the presence and distribution of OPN in reactionary and reparative dentine by provoking extrusion of the rat incisor. The right upper incisors of 3-month-old male rats were extruded 3 mm and then repositioned into their original sockets. At 3, 7, 10, 15, 20, 30 and 60 days after surgery, the incisors were fixed in glutaraldehyde-formaldehyde and then processed for scanning and transmission electron microscopy and for immunocytochemistry for OPN. After extrusive trauma, the dentine-pulp interface showed the presence of reactionary and reparative dentine, which varied in aspect, thickness and related cells. OPN was not detected in the physiological and reactionary dentine, while it was strongly immunoreactive in the matrix that surrounded the entrapped cells of reparative dentine. In addition, original odontoblasts subjacent to the physiological dentine contained OPN in their Golgi region. The present findings showed that reparative dentine shares some structural characteristics with primary bone, especially in relation to its OPN content. The odontoblast-like cells resemble osteoblasts rather than odontoblasts.

Efeito de água de coco e do leite pasteurizado sobre a superfície radicular de dentes reimplantados: estudo histológico em ratos / Effect of green coconut water and pasteurized milk on the radicular surface of reimplanted teeth: histological analysis in rats

O reimplante dentário consiste na reposição do dente avulsionado no seu respectivo alvéolo. Seu sucesso pode ser prejudicado pelo fato de o dente reimplantado desenvolver reabsorção radicular, sendo esta minimizada quando se preserva a vitalidade do ligamento periodontal, a qual está diretamente relacionada com o tempo de permanência extra-alveolar e o meio de armazenagem. O presente trabalho avaliou, mediante estudo histológico em ratos, a influência da solução de água de coco verde in natura sobre a superfície radicular de dentes extraídos e reimplantados, quando comparada à do leite pasteurizado em relação à presença e natureza da reabsorção radicular e da anquilose. Foram utilizados 80 ratos Rattus novergicus, Albinus Wistar, machos, que tiveram seus dentes extraídos, armazenados nas soluções propostas e reimplantados. Os ratos foram divididos em grupos: Grupo I (leite pasteurizado, 30 minutos); Grupo II (leite pasteurizado, 90 minutos); Grupo III (água de coco, 30 minutos); e Grupo IV (água de coco, 90 minutos). Os animais de cada grupo foram sacrificados nos períodos de 10, 30, 60 e 90 dias. Os resultados obtidos mostraram que a reabsorção inflamatória foi o fenômeno mais freqüente. Os dentes conservados em leite pasteurizado por 30 minutos e 90 minutos demonstraram menores índices de reabsorção e anquilose quando comparados com aqueles dos demais grupos. A água de coco mostrou-se inadequada para a conservação de dentes avulsionados.