Teresa Lúcia Lamano Carvalho

Histologic and histometric evaluation of rat alveolar wound healing around polyurethane resin implants

The biocompatibility of polyurethane resin-implants derived from castor bean (Ricinus communis) was analyzed in the rat dental alveolus. Histometric evaluation of trial areas adjacent to the implants showed, by week 1, the polymer granules encircled by a conspicuous capsule and surrounded by immature connective tissue. By weeks 2 and 3, the implants were surrounded by less prominent fibrous capsules and most of the tested area was occupied by mature trabecular bone. By week 6, the fibrous capsule was thinner and the tested area was almost totally covered with bone, which in several places was in close contact with the implants. The results suggest that the material is compatible, as it was progressively integrated into alveolar bone in the wound-healing process.

Histometric study of socket healing after tooth extraction in rats treated with diclofenac

The purpose of the present study was to investigate if diclofenac administration interferes with the time course of alveolar wound healing in rats. Forty-two Wistar rats were used, 21 rats received 10 mg/kg/day of diclofenac one day before and 4 days after extraction of the right maxillary incisors and 21 rats received saline. The animals were sacrificed 7, 14 and 21 days after tooth extraction. Progressive new bone formation and a decrease in the volume fraction of blood clot and connective tissue from 1 to 3 weeks after tooth extraction was quantified using the histometric point-counting method. Diclofenac treatment caused a significant delay in new bone formation in association with an impairment of blood clot remission/organization.

Chronology of alveolar healing following immediate implantation of Ricinus communis polyurethane resin : Histometric analysis in rats

The purpose of the present study was to determine whether granules of Ricinus communis polyurethane resin implanted immediately after tooth extraction interfere with the time course of alveolar wound healing in rats. Progressive bone neoformation in parallel to a decrease in the volume fraction of connective tissue was quantified by a histometric method 1, 2, 3, and 6 weeks after tooth extraction. In spite of the biocompatible nature, the presence of polyurethane resin granules in the cervical third led to a small (9-22%) but significant delay in bone formation in the middle and apical alveolar thirds from the second week on, as compared to controls.

Bioactive Glass Efficacy in the Periodontal Healing of Intrabony Defects in Monkeys

The purpose of this study was the histomorphologic analysis of the efficacy of bioactive glass particles with a narrow size range (Biogran) in the periodontal healing of 2-wall intrabony defects in monkeys. The 2-wall defects were made in the mesial area of the left and right second premolars of four monkeys, filled with gutta-percha and, after 15 days, they were debrided and either naturally filled with coagulum (control) or implanted with bioactive glass (test). In the control sites, the junctional epithelium migrated up to the base of the defect. The presence of newly formed cementum was more significant in the test defects. Both control and test sites showed newly formed bone at the base of the defect. The test defects presented foci of newly formed bone around and within the glass particles localized in the middle third, distant from the defect walls. Histologic analysis showed that the 300- to 355-microm bioactive glass particles aided new periodontal insertion. In conclusion, the tested bioactive glass had better healing potential than debridement only. The graft material showed a promising inhibition of apical migration of the junctional epithelium and greater cementum deposition on the radicular surface of the intrabony defects. The replacement of bioactive glass particles by new bone occurred due not only to an osteoconductive property, but also to an osteostimulatory capacity. Future investigations should evaluate this potential comparatively or together with other grafting materials, regenerative techniques and biological modifiers, as well as assess the longitudinal stability of the new attachment.

Alcohol intake and osseointegration around implants: a histometric and scanning electron microscopy study.

Alveolar wound healing can be modified by local and systemic factors. The aim of this study was to evaluate the possible effect of alcoholic beverage administration (sugarcane brandy) on reparative bone formation around hydroxyapatite/tricalcium phosphate implants inside the alveolar socket. Male Wistar rats had their upper right incisors extracted and the bioceramic granules implanted in the alveoli. The animals received increasing concentrations of brandy until 30° Gay-Lussac was achieved starting 30 days before dental extraction and maintained for periods varying from 1 hour to 6 weeks, until sacrifice. Blood alcohol concentration analysis was performed as well as histological and histometric analysis through light and scanning electron microscopy to examine the relation between alveolar healing components, including new bone trabeculae, and the implants. Blood alcohol concentration was significantly higher in treated animals compared with controls. A significant delay in reparative bone formation was detected in the alveolus of alcoholic rats by a histometric differential point counting method, whereas the presence of the bioceramic in the alveolar socket improved alveolar wound healing in alcohol-treated rats. It is suggested that the osteoconductive properties of this bioceramic accelerated alveolar wound healing in alcoholic rats.

Influence of treatment with intranasal corticosteroids on the nasal mucosa, weight, and corticosteroid concentration in rats.

Background The effect of intranasal corticosteroids on the nasal epithelium mucosa is an important parameter of treatment safety. This study was designed to examine whether treatment with topical corticosteroids in patients with allergic rhinitis causes atrophic nasal mucosal changes, when compared with systemic corticosteroids, in rats. Methods Male Wistar rats were treated daily during 7 weeks with topical administration with 10 microliters of normal saline (control group), 10 microliters of mometasone furoate group, 10 microliters of triamcinolone acetonide (T group), and 8 mg/kg of daily subcutaneous injections of methylprednisolone sodium succinate (MP group). Body weight was evaluated weekly. At the end of the treatment, rats were killed by decapitation to collect blood for determination of corticosterone levels and nasal cavities were prepared for histological descriptive analyses. Results Treatment with T and MP decreased body weight. Plasma corticosterone concentration was significantly reduced by MP treatment and presented a clear tendency to decrease after T treatment. Histological changes observed in group T included ripples, cell vacuolization, increase in the number of nuclei, and decrease in the number of cilia in the epithelial cells. Conclusion Growth and corticosterone concentration were impaired by T and MP at the same proportion, suggesting a role of this hormone in body gain. With the exception of T, intranasal or systemic treatment with the corticosteroids evaluated in this study did not affect nasal mucosa.