Puricelli biconvex arthroplasty: an experimental study in sheep.

BACKGROUND: The aim of this study was to establish a sheep model of the Puricelli biconvex arthroplasty (ABiP) technique in sheep for evaluating its functional, biological and histological parameters. METHODS: Ten Corriedale black sheep were submitted to TMJ total reconstruction with poly(methyl methacrylate) (PMMA) using ABiP and euthanized after 45 (n = 5) or 90 (n = 5) days. Control animals (n = 2) underwent sham operations and were euthanized after 45 days. Variables were assessed before the surgery (T0), immediately after (T1) and at 45 or 90 postoperative days (T2). RESULTS: Histological analyses showed regression of inflammatory cells over the follow-up period. PMMA showed reduced porosity and roughness in the articular contact area. PMMA temporal components showed linear and volumetric wear in comparison to control, but no foreign body reaction was observed. The reconstructions were stable in all animals. The amplitude of mouth opening and left lateral movements were maintained, except for a reduction in the range of right lateral movements at day 90 in the experimental group. Clinical, macroscopic and radiographic observations showed that the reconstructions were stable. CONCLUSIONS: The analysis of functional, biological and histological parameters in sheep submitted to ABiP showed stable results of the procedure, with maintenance of body weight and all mandibular movements, save contralateral mandibular movement, suggesting that joint function was completely maintained following the procedure. This experimental study provides support for clinical results previously reported of the ABiP technique in TMJ reconstruction procedures.

Astroglial Alterations in the Hippocampus of Rats Submitted to a Single Trans-Cranial Direct Current Stimulation Trial.

Evidence indicates that transcranial direct current stimulation (tDCS) provides therapeutic benefits in different situations, such as epilepsy, depression, inflammatory and neuropathic pain. Despite the increasing use of tDCS, its cellular and molecular basis remains unknown. Astrocytes display a close functional and structural relationship with neurons and have been identified as mediators of neuroprotection in tDCS. Considering the importance of hippocampal glutamatergic neurotransmission in nociceptive pathways, we decided to investigate short-term changes in the hippocampal astrocytes of rats subjected to tDCS, evaluating specific cellular markers (GFAP and S100B), as well as markers of astroglial activity; glutamate uptake, glutamine synthesis by glutamine synthetase (GS) and glutathione content. Data clearly show that a single session of tDCS increases the pain threshold elicited by mechanical and thermal stimuli, as evaluated by von Frey and hot plate tests, respectively. These changes involve inflammatory and astroglial neurochemical changes in the hippocampus, based on specific changes in cell markers, such as S100B and GS. Alterations in S100B were also observed in the cerebrospinal fluid of tDCS animals and, most importantly, specific functional changes (increased glutamate uptake and increased GS activity) were detected in hippocampal astrocytes. These findings contribute to a better understanding of tDCS as a therapeutic strategy for nervous disorders and reinforce the importance of astrocytes as therapeutic targets.

Evaluation of the immediate effects of a single transcranial direct current stimulation session on astrocyte activation, inflammatory response, and pain threshold in naïve rats.

Transcranial direct current stimulation (tDCS) has demonstrated clinical benefits such as analgesia, anti-inflammatory, and neuroprotective effects. However, the mechanisms of action of a single tDCS session are poorly characterized. The present study aimed to evaluate the effects of a single tDCS session on pain sensitivity, inflammatory parameters, and astrocyte activity in naive rats. In the first experiment, sixty-day-old male Wistar rats (n = 95) were tested for mechanical pain threshold (von Frey test). Afterward, animals were submitted to a single bimodal tDCS (0.5 mA, 20 min) or sham-tDCS session. According to the group, animals were re-tested at different time intervals (30, 60, 120 min, or 24 h) after the intervention, euthanized, and the cerebral cortex collected for biochemical analysis. A second experiment (n = 16) was performed using a similar protocol to test the hypotheses that S100B levels in the cerebrospinal fluid (CSF) are altered by tDCS. Elisa assay quantified the levels of tumor necrosis factor-alfa (TNF-α), interleukin-10 (IL10), S100 calcium-binding protein B (S100B), and Glial fibrillary acidic protein (GFAP). Data were analyzed using ANOVA and independent t-test (P < 0.05). Results showed that tDCS decreased pain sensitivity (30 and 60 min), cerebral TNF-α and S100B levels (30 min). CSF S100B levels increased 30 min after intervention. There were no differences in IL10 and GFAP levels. TCDS showed analgesic, anti-inflammatory, and neuroprotective effects in naive animals. Therefore, this non-invasive and inexpensive therapy may potentially be a preemptive alternative to reduce pain, inflammation, and neurodegeneration in situations where patients will undergo medical procedures (e.g., surgery).

Redução de dor, edema e trismo: benefícios do uso da dexametasona via intramuscular como medicação preemptiva na cirurgia oral / Reduction of pain, swelling and trismus: benefits of using intramuscular dexamethasone as preemptive medication in oral surgery / Reducción del dolor, edema y trismo: beneficios del uso de dexametasona intramuscular como medicación preventiva en cirugía oral

Complicações pós-operatórias como edema, dor e trismo são comuns em cirurgias orais. Terapias, como o uso de analgésicos e anti-inflamatórios, são indicadas para estas complicações. No entanto, intervenções pré-operatórias podem ser alternativas. Desta forma, o presente estudo avaliou o efeito da dexametasona no edema, intensidade de dor e abertura de boca (trismo) no pós-operatório de retirada de terceiros molares inferiores. Pacientes (n=14, 9 mulheres) foram incluídos em um estudo clínico, cruzado, cego, randomizado, placebo-controlado e boca dividida. Pacientes receberam aleatoriamente medicação preemptiva (dexametasona 8mg, intramuscular, músculo masseter) ou placebo (soro fisiológico) uma hora antes da primeira cirurgia. O procedimento contralateral foi realizado 21 dias após. Avaliou se o edema e a abertura bucal nos momentos pré-operatórios e no 3º e 7º dias pós-operatórios, além de dor espontânea (imediatamente, 2 e 24 horas, 3 dias e 7 dias). Os dados foram analisados usando anova de medidas repetidas seguida do teste post hoc LSD de Fisher. Comparado ao placebo, a medicação reduziu edema (3 dias), dor (2 e 24 horas) e trismo (3 dias). Os resultados sugerem que o uso preemptivo da dexametasona intramuscular é capaz de aumentar o bem-estar dos pacientes submetidos a cirurgias orais, tendo o potencial de reduzir os custos pós-operatórios... (AU)

Postoperative complications such as edema, pain, and trismus are common in oral surgery. Therapies, such as the use of painkillers and anti inflammatory drugs, are indicated for the reversal of these complications. However, preoperative (preemptive) interventions can be alternatives. Thus, the present study aimed to evaluate the effect of dexamethasone on edema, pain intensity, and mouth opening (trismus) in the postoperative period of removal of impacted lower third molars. Patients (n = 14, 9 women) were included in a clinical, crossover, blinded, randomized, placebo-controlled, and divided mouth study. Preemptive mediation (dexamethasone 8mg, intramuscular, masseter muscle) or placebo (saline) was randomly given before the first surgery. The contralateral procedure was performed 21 days later. In the postoperative period, edema, mouth opening (preoperative, 3 and 7 days), and spontaneous pain (immediately, 2 and 24 hours, 3 days and 7 days) were analyzed. The data were analyzed using the one-way repeated measures ANOVA followed by Fisher's LSD post hoc. Compared to placebo, the medication reduced edema (3 days), pain (2 and 24 hours), and trismus (3 days). The results suggest that the preemptive use of dexamethasone is able to increase the well-being of patients undergoing oral surgeries, with the potential to reduce postoperative costs... (AU)

Las complicaciones posoperatorias como hinchazón, dolor y trismo son comunes en las cirugías orales. Las terapias, como el uso de analgésicos y antiinflamatorios, están indicadas para estas complicaciones. Sin embargo, las intervenciones preoperatorias pueden ser alternativas. Así, el presente estudio evaluó el efecto de la dexametasona sobre el edema, la intensidad del dolor y la apertura de la boca (trismo) en el postoperatorio de remoción del tercer molar inferior. Los pacientes (n = 14, 9 mujeres) se incluyeron en un estudio clínico, cruzado, ciego, aleatorizado, controlado con placebo y de boca dividida. Los pacientes recibieron aleatoriamente medicación preventiva (8 mg de dexametasona, intramuscular, músculo masetero) o placebo (solución salina) una hora antes de la primera cirugía. El procedimiento contralateral se realizó 21 días después. Se evaluó el edema y la apertura de la boca en el preoperatorio y en el tercer y séptimo días postoperatorios, además del dolor espontáneo (inmediato, 2 y 24 horas, 3 días y 7 días). Los datos se analizaron utilizando anova de medidas repetidas seguido de la prueba post hoc de LSD de Fisher. En comparación con el placebo, el medicamento redujo el edema (3 días), el dolor (2 y 24 horas) y el trismo (3 días). Los resultados sugieren que el uso preventivo de dexametasona intramuscular puede aumentar el bienestar de los pacientes sometidos a cirugía oral, con el potencial de reducir los costos posoperatorios... (AU)

Improvement in the chemical structure and biological activity of surface titanium after exposure to UVC light.

Ultraviolet (UV) irradiation has been proposed as a method to reverse the aging process of titanium. However, the intensity, exposure time and wavelength that provide the best results have not yet been determined. The objective of this study was to evaluate the effects of photocatalysis by ultraviolet C light on the time-dependent aging of titanium and to analyze the irradiated titanium for changes in structure and in vitro biological activity, with regard to different exposure times. A titanium photofunctionalization device was developed with characteristics different from those on the market. The sample was composed of titanium disks irradiated for different times of exposure to ultraviolet C light (0, 15, 30 and 60 min). The disks were tested for surface wettability (water contact angle), topography (scanning electron microscopy-SEM) and chemical composition (X-ray photoelectron spectroscopy), and effects on cell adhesion (cell culture and SEM) and cell viability by sulforhodamine B (SRB). Ultraviolet C treatment caused changes in titanium surface characteristics, such as increased wettability and removal of hydrocarbons from the surface after 15 min of exposure in the chamber developed. The biological characteristics of the material also appear to have changed, with improved cell adhesion and viability. Photofunctionalization of titanium proved to be effective for the treatment of aged surfaces, with significant modifications in the surface chemical structure and biological activity of the material.

Reduction of osteoarthritis severity in the temporomandibular joint of rabbits treated with chondroitin sulfate and glucosamine.

Osteoarthritis is a degenerative disease that causes substantial changes in joint tissues, such as cartilage degeneration and subchondral bone sclerosis. Chondroitin sulfate and glucosamine are commonly used products for the symptomatic treatment of osteoarthritis. The aim of the present study was to investigate the effects of these products when used as structure-modifying drugs on the progression of osteoarthritis in the rabbit temporomandibular joint. Thirty-six New Zealand rabbits were divided into 3 groups (n = 12/group): control (no disease); osteoarthritis (disease induction); and treatment (disease induction and administration of chondroitin sulfate and glucosamine). Osteoarthritis was induced by intra-articular injection of monosodium iodoacetate. Animals were killed at 30 and 90 days after initiation of therapy. The treatment was effective in reducing disease severity, with late effects and changes in the concentration of glycosaminoglycans in the articular disc. The results indicate that chondroitin sulfate and glucosamine may have a structure-modifying effect on the tissues of rabbit temporomandibular joints altered by osteoarthritis.

Condylotomy to Reverse Temporomandibular Joint Osteoarthritis in Rabbits.

PURPOSE: Osteoarthritis (OA) of the temporomandibular joint (TMJ) is characterized by local tissue degeneration and pain. Treatments have been aimed at reducing symptoms, and only some can interfere with the progression of pathophysiologic changes caused by OA. Condylotomy is an alternative treatment for patients with OA refractory to conventional treatment. The aim of the present animal study was to investigate the influence of condylotomy on TMJ OA in New Zealand rabbits. MATERIALS AND METHODS: The 36 rabbits were divided into 3 groups: the osteoarthritis group (OG; induced OA), treatment group (TG; induced OA plus condylotomy), and control group (CG; neither OA nor surgery). OA was induced using intra-articular monosodium iodoacetate injection for 40 days. The rabbits in the TG underwent condylotomy and were killed 20, 40, and 60 days after treatment. The rabbits in the CG and OG were killed at the same points. RESULTS: The articular joint condition was better in the TG 60 days after surgery (P = .032). A direct comparison revealed regression of TMJ OA over time among the treated rabbits (P = .008). Surgical treatment promoted mandibular condylar remodeling in the TG, reversing the tissue degeneration caused by OA. CONCLUSIONS: Our findings suggest that condylotomy could be an option for the treatment of OA and prevent damage to TMJ structures. This could be of particular importance for patients without satisfactory responses to more conservative treatment.

Occurrence of dermoid cyst in the floor of the mouth: the importance of differential diagnosis in pediatric patients.

Lesions in the floor of the mouth can be a challenging diagnosis due to the variety of pathological conditions that might be found in this area. Within a broad range of lesions, attention has to be addressed to those that require specific management, such as a dermoid cyst (DC) and a ranula. Especially in pediatric patients, in whom the failure of diagnosis can postpone the correct treatment and cause sequelae later in life. DC, a developmental anomaly, is managed primarily by surgical resection. On the other hand, ranula is a pseudocyst that may be treated by marsupialization. This article reports a large and painful lesion in the floor of the mouth in a pediatric patient. With a diagnostic hypothesis of ranula, two surgical interventions were performed, but there were recurrences of the lesion. Subsequently, the patient was referred to the Oral and Maxillofacial Surgery Unit for re-evaluation. Computed tomography showed a semi-transparent image suggesting a cystic formation. Another surgical procedure was performed where the lesion was completely removed. Anatomopathological analysis confirmed the diagnosis of DC. The five-year follow-up showed no signs of recurrence. This article indicates that although DC in the floor of the mouth is rare, it should be considered in the differential diagnosis of other diseases in this area. This precaution may be particularly important in the following circumstances: 1) Similar lesions that have different therapeutic approaches and, 2) To prevent future sequelae in pediatric patients.

Occurrence of dermoid cyst in the floor of the mouth: the importance of differential diagnosis in pediatric patients

Abstract Lesions in the floor of the mouth can be a challenging diagnosis due to the variety of pathological conditions that might be found in this area. Within a broad range of lesions, attention has to be addressed to those that require specific management, such as a dermoid cyst (DC) and a ranula. Especially in pediatric patients, in whom the failure of diagnosis can postpone the correct treatment and cause sequelae later in life. DC, a developmental anomaly, is managed primarily by surgical resection. On the other hand, ranula is a pseudocyst that may be treated by marsupialization. This article reports a large and painful lesion in the floor of the mouth in a pediatric patient. With a diagnostic hypothesis of ranula, two surgical interventions were performed, but there were recurrences of the lesion. Subsequently, the patient was referred to the Oral and Maxillofacial Surgery Unit for re-evaluation. Computed tomography showed a semi-transparent image suggesting a cystic formation. Another surgical procedure was performed where the lesion was completely removed. Anatomopathological analysis confirmed the diagnosis of DC. The five-year follow-up showed no signs of recurrence. This article indicates that although DC in the floor of the mouth is rare, it should be considered in the differential diagnosis of other diseases in this area. This precaution may be particularly important in the following circumstances: 1) Similar lesions that have different therapeutic approaches and, 2) To prevent future sequelae in pediatric patients.

Evaluation of different procedure involved in the Transcranial Direct Current Stimulation (tDCS) technique experimental application

Introduction: The transcranial direct current stimulation (tDCS) is a non-invasive technique, which induces neuroplastic changes in the central nervous system of animals and humans. Furthermore, tDCS has been suggested as a therapeutic tool for pain management. The aim of this study was to standardize a non-invasive tDCS technique indexed by the nociceptive response of rats submitted to different conditions necessary to the tDCS application. Method: 60-day-old male Wistar rats (n=65), divided into 6 groups: control(C); non-active sham (NAS); active-sham (AS); active-sham restrained (ASR); non-active sham restrained (NASR); active tDCS treatment. Animals received treatment during 30 seconds (sham-active) or 20 minutes (restraint and tDCS)/8 days. Nociceptive threshold was assessed by Hot Plate test at baseline, immediately and 24h after the first session, immediately and 24h after the last session. Variance analysis of repeated measurements followed by Bonferroni was performed for intra-group comparison. Results: Physical restraint and 30 seconds stimulation (sham-tDCS) increased pain sensitivity (P≤0.05), and tDCS treatment was able to prevent the thermal hyperalgesia. Our original tDCS montage is similar to that used in the procedure with humans, because it is not an invasive technique. The electrodes are positioned on the head, and the animals are immobilized during the 20-minute treatment. As this procedure could involve behavior and neurochemical alterations due to stress induced by restriction (thus, it creates a research bias), we hypothesized that a 30-second electrical stimulus application (sham-tDCS) and the physical restriction used during tDCS treatment might alter nociceptive response in rats. Conclusion: There are methodological limitations in the present tDCS-technique. Although active-tDCS treatment is able to prevent these harmful effects, interference of these factors has to be considered during the results' analysis. Future adaptations of the tDCS-technique in rats are required to evaluate its therapeutic effects (AU)

Rabbit model for osteoarthrosis of the temporomandibular joint as a basis for assessment of outcomes after intervention.

Osteoarthritis can be induced in the temporomandibular joint (TMJ) by primary or secondary trauma, or overloading of the joint. We have therefore systematically evaluated the histological progression of experimental osteoarthritis induced by a high concentration of monosodium iodoacetate into the rabbit TMJ. These findings may contribute to the establishment of a protocol to investigate the benefits of treatment of osteoarthritis of the TMJ. We used 21 male New Zealand rabbits; the 15 in the test group were given an intra-articular injection of monosodium iodoacetate 10mg/ml into the right TMJ and were killed after 60 (n=5), 80 (n=5), and 100 days (n=5). The six in the control group were given an injection of saline into the right TMJ. The assessment system for osteoarthritis based on six grades was used for the histological analysis of severity. The model was effective in producing histological changes in the cartilage consistent with those found in osteoarthritis at all time points. The within-group analysis indicated that the disease did not progress after 60 days. The successful induction of osteoarthritis in this way, its stabilisation after 60 days, and the appropriate size of the animal suggest that this experimental model is ideal for future studies of the effectiveness of treatment in osteoarthritis of the TMJ.

Abordagens técnicas inovadoras em Cirurgia e Traumatologia Bucomaxilofacial / Innovative technique approaches in Oral and Maxillofacial Surgery

Ao longo da história, a ciência tem colaborado com o desenvolvimento de terapias que suprem as novas demandas da sociedade, sempre com o objetivo de manter a saúde e a integridade do ser humano. Avanços tecnológicos em áreas afins, como a anestesia geral e a introdução dos biomateriais, impulsionaram a evolução da Odontologia. Particularmente a Cirurgia e Traumatologia Bucomaxilofaciais (CTBMF) tem desenvolvido técnicas cirúrgicas mais elaboradas que geram benefícios a uma parcela da população que não possuía alternativas terapêuticas anteriormente. Equipes cirúrgicas brasileiras têm assumido papel de destaque na busca de suprir limitações terapêuticas. Como por exemplo, retenções dentárias sem possibilidades de tratamentos conservadores, hoje podem ser tratadas através de técnicas como a Apicotomia e a Laçada Dupla. Similarmente, pacientes portadores de anquilose da articulação temporomandibular (ATM) possuem opção de serem tratados com a Artroplastia Biconvexa de Puricelli. Esta técnica requer menor exérese tecidual, utiliza material aloplástico de baixo custo e restaura a função articular. E por fim, técnicas desenvolvidas no Brasil têm colaborado ao aperfeiçoamento de metodologias mundialmente consagradas, como é o caso da Osteotomia Mandibular de Puricelli que confere maior estabilidade entre os fragmentos ósseos nas cirurgias para correção de deformidades dentofaciais. Desta forma, o presente trabalho tem por objetivo a exposição e discussão da colaboração científica e técnica destas terapias cirúrgicas (desenvolvidas no Departamento de Cirurgia e Ortopedia da Universidade Federal do Rio Grande do Sul) nos diferentes procedimentos, onde são indicadas.

Throughout history, the development of science has collaborated with the progress of new therapies based on society's demands to maintain public health and its physical integrity. Technological development in basic areas (i.e. general anesthesia and biomaterials) helped the progress of Dental Science. For example, the Oral and Maxillofacial Surgery (OMS) was able to develop novel and more advanced surgical techniques bringing clinical benefits that did not exist earlier. Brazilian research groups have played an important role in the development of new alternatives to surpass these therapeutic limitations. For instance, some cases of tooth impaction, which could only be treated by dental extraction, are currently resolved through alternative surgical techniques such as Apicotomy and Double Traction, preventing tooth loss. Likewise, patients with temporomandibular joint (TMJ) ankylosis can be favored by a surgical treatment called Puricelli Biconvex Arthroplasty. This procedure has minimally invasive osteotomy, uses a financial affordable alloplastic material, and maintains joint stability. Finally, Brazilian techniques have contributed to improve other well-established surgical treatments. This is the case of the Puricelli Osteotomy, which provides a more stable position for the mandible during orthognathic surgery. Therefore, the aim of the present paper is to summarize and discuss the scientific and methodological contributions of these surgical techniques (developed by the Department of Surgery and Orthopedic of Universidade Federal do Rio Grande do Sul) and their indications.

Exogenously induced brain activation regulates neuronal activity by top-down modulation: conceptualized model for electrical brain stimulation.

Physiological and exogenous factors are able to adjust sensory processing by modulating activity at different levels of the nervous system hierarchy. Accordingly, transcranial direct current stimulation (tDCS) may use top-down mechanisms to control the access for incoming information along the neuroaxis. To test the hypothesis that brain activation induced by tCDS is able to initiate top-down modulation and that chronic stress disrupts this effect, 60-day-old male Wistar rats (n = 78) were divided into control; control + tDCS; control + sham-tDCS; stress; stress + tDCS; and stress + sham-tDCS. Chronic stress was induced using a restraint stress model for 11 weeks, and then, the treatment was applied over 8 days. BDNF levels were used to assess neuronal activity at spinal cord, brainstem, and hippocampus. Mechanical pain threshold was assessed by von Frey test immediately and 24 h after the last tDCS-intervention. tDCS was able to decrease BDNF levels in the structures involved in the descending systems (spinal cord and brainstem) only in unstressed animals. The treatment was able to reverse the stress-induced allodynia and to increase the pain threshold in unstressed animals. Furthermore, there was an inverse relation between pain sensitivity and spinal cord BDNF levels. Accordingly, we propose the addition of descending systems in the current brain electrical modulation model.

Using Novafil: would it make suturing easier? / Uso do Novafil: isto facilitará a execução da sutura?

The use of monofilament nonabsorbable suture materials is not common in dentistry. Althought it is known that multifilaments suture materials induce greater cellular reaction, most dentist prefer to use cotton and silk. Rigidity and package memory are desadvantage of monofilament nonabsorbable suture materials. A new material, Polybutester (Novafil), has been used successfully in medicine but its use is not common in dentistry. Seventy male and male Wistar rats were used to study the clinical response of skin and abdominal wall muscle to the use Novafil and nylon sutures. Under general anesthesia, standard wounds were created in the dorsum and abdoman of the animals and sutured with either Novafil or nylon. The animals were sacrificed immediately, 12, 24, and 72 hours and at 4, 5 and 7 days to evaluate the clinical aspect of both wounds. Polybutester presented some adventages such as strength, lack of package memory, elasticity and flexebility which made suturing quicker and easier. Some subjects presented abdminal wound edema during the period and 6 animals developed infection of abdominal wounds within seven days. These initial findings show that Novafil easy to handle and would be better tolerated in the mouth than nylon resulting in less discomfort for the patient. Novafil can be used safely on skin and mucosal wounds and, if necessary, it can be used in internal sutures because it irritates less than nylon