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.

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.

Successful conservative treatment of osteoradionecrosis of the mandible associated with pathological fracture

Treatment of patients with osteoradionecrosis (ORN) of the mandible associated with pathologic fractures usually consists of a continuity resection of the mandible, leading to severe impairment of the patient's health and quality of life. Conservative treatment may be alternatively attempted; however, it is not usually employed. Here, we report a successful conservative treatment of ORN associated with pathologic fracture. A 48-year-old black man who had undergone radiotherapy for a squamous cell carcinoma in the tongue 6 years previously sought care complaining of facial swelling and draining episodes. Since the patient was fiercely resistant to any kind of hospital-based therapy, a conservative approach was proposed. Daily irrigations with 2% potassium iodate, followed by 3% oxygenated water, were performed by the patient at his house. In addition, local cleaning and debridement were weekly performed at our dental clinic. Systemic antibiotics were also administered. Throughout the therapy course, bone fragments were spontaneously exfoliated. Resolution of the ulcer and fracture was observed after 6 weeks of treatment. This report shows that ORN may be conservatively managed in specific situations, with good cosmetic and functional

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.

Oral squamous cell carcinoma: a retrospective study of 740 cases in a Brazilian population

The purpose of this study was to evaluate, retrospectively, the profile of patients with oral squamous cell carcinoma. They were referred to two hospitals of Belo Horizonte (MG, Brazil) between 1986 and 1996. The medical records of 740 patients presenting oral squamous cell carcinoma were reviewed in detail. The TNM classification and staging, age, gender, race, occupation, and site of the primary tumor were recorded. The male-to-female ratio was 4.8:1. The mean age was 58.6 years. Most of the patients were in their sixties and were farm workers. The tumors were found principally on the tongue. There was a close relationship between some habits (tobacco and alcohol consumption) and the development of oral squamous cell carcinoma. Most of the patients sought medical care in the first year, even though almost half of them had lesions in stage T4. The identification of the characteristics of this specific population might reflect either accomplishments or problems in oral cancer control and can enable the development of a primary prevention program for oral squamous cell carcinoma.

Palatal mucoepidermoid carcinoma in a child

Salivary gland tumors in childhood and adolescence are rare. The clinical and histological picture of a case of palatal mucoepidermoid carcinoma in a 13 year-old girl is presented and the diagnostic and therapeutic features of the condition are discussed.

Anaplastic Wilms' tumour, a subtype displaying poor prognosis, harbours p53 gene mutations

The genetics of Wilms' tumour (WT), a paediatric malignancy of the kidney, is complex. Inactivation of the tumour suppressor gene, WT1, is associated with tumour aetiology in approximately 10-15% of WTs. Chromosome 17p changes have been noted in cytogenetic studies of WTs, prompting us to screen 140 WTs for p53 mutations. When histopathology reports were available, p53 mutations were present in eight of eleven anaplastic WTs, a tumour subtype associated with poor prognosis. Amplification of MDM2, a gene whose product binds and sequesters p53, was excluded. Our results indicate that p53 alterations provide a molecular marker for anaplastic WTs.

Body stature as a risk factor for diabetic sensory neuropathy

Risk factors for vibratory perception threshold abnormalities were studied in 200 diabetic patients between the ages of 21 and 70 years and 62 control subjects of similar age. Vibratory perception (measured with the Biothesiometer) was absent over one or both halluces in 18 percent of the patients. In a stepwise multiple logistic regression analysis, height was the variable most strongly associated with absent vibratory perception (coefficient +/- SE, 0.501 +/- 0.097/inch; p less than 0.0001). Duration of diabetes (p less than 0.001), age (p less than 0.05), and ethanol use (p less than 0.05) were also associated. The prevalence of absent vibratory perception in the lower, middle, and upper thirds of the height distribution was 0.05, 0.08, and 0.40, respectively. Among the control subjects, there was no association of vibratory perception with either height or ethanol use. These data strongly suggest that body stature is a major risk factor for diabetic sensory neuropathy.