Leandro Araújo Fernandes

Treatment of experimental periodontal disease by photodynamic therapy in immunosuppressed rats

BACKGROUND AND OBJECTIVE The aim of this study was to compare photodynamic therapy (PDT) as an adjunctive treatment of induced periodontitis with scaling and root planing (SRP) in dexamethasone-inhibited rats. MATERIAL AND METHODS The animals were divided into two groups: ND (n=90), saline solution treatment; D (n=90), dexamethasone treatment. In the ND and D Groups, periodontal disease was ligature-induced at the first mandibular molar. After 7 days, the ligature was removed and all animals received SRP and were divided according to the following treatments: SRP, saline solution; Toluidine Blue-O (TBO), phenothiazinium dye; and PDT, TBO and laser irradiation. Ten animals in each treatment were killed at 7, 15 and 30 days. The radiographic and histometric values were statistically analysed. RESULTS In the ND and D Groups, radiographic analysis showed less bone loss in animals treated by PDT in all the experimental periods than SRP and TBO at 15 days (p<0.05). After a histometric analysis was carried out in the ND and D groups, the animals treated by PDT showed less bone loss in all periods than SRP and TBO after 15 days (p<0.05). CONCLUSIONS The PDT was an effective adjunctive treatment of induced periodontitis compared with SRP in dexamethasone-inhibited rats.

Adjunctive antimicrobial photodynamic treatment of experimentally induced periodontitis in rats with ovariectomy.

BACKGROUND The aim of this study is to compare antimicrobial photodynamic therapy (aPDT) as an adjunctive therapy to scaling and root planing (SRP) for the treatment of experimentally induced periodontitis in rats with ovariectomy (OVX) that are or are not treated with estrogen replacement. METHODS A total of 270 female rats were divided into three groups: 1) normal rats; 2) rats with OVX; and 3) rats with OVX with estrogen replacement. Periodontal disease was induced through the introduction of a cotton thread around the mandibular left first molar. After 7 days, the ligature was removed, and the rats were randomly divided into the following treatment groups: 1) SRP plus saline solution; 2) SRP plus low-level laser therapy (LLLT); and 3) SRP plus toluidine blue O irrigation followed by LLLT. Ten rats from each group were euthanized at days 7, 15, and 30 after dental treatment. Bone loss (BL) in the furcation region was evaluated using histometric and immunohistochemical analyses. RESULTS aPDT treatment resulted in reduced BL compared with SRP treatment at all time points. Additionally, rats treated with aPDT exhibited reduced numbers of tartrate-resistant acid-phosphatase-positive cells and more proliferating cell nuclear antigen-positive cells in all treatment groups regardless of estrogen status. Whereas rats treated with aPDT showed weak immunoreactivity to the receptor activator of nuclear factor-κ B ligand at day 7 post-treatment, strong osteoprotegerin immunoreactivity was observed at day 15 post-treatment. CONCLUSION aPDT is an effective adjunctive therapy for the treatment of periodontitis in rats with OVX that are or are not given estrogen replacement therapy.

Adjuvant Therapy With Sodium Alendronate for the Treatment of Experimental Periodontitis in Rats

BACKGROUND This study assesses the effects of topical sodium alendronate (SA) as an adjuvant to the mechanical treatment of ligature-induced periodontitis in rats. METHODS Ninety animals were subjected to the induction of periodontitis via the installation of a ligature around the mandibular left first molar. After 7 days, the ligature was removed, and the animals were distributed into the following groups: 1) NT group (n = 30), no treatment; 2) SRP group (n = 30), scaling and root planing (SRP) and local irrigation with physiologic saline solution; and 3) SRP/SA group (n = 30), SRP and local irrigation with SA (10(-5) M). Ten animals from each group were euthanized at 7, 15, and 30 days after treatment. Histologic and histometric analyses were performed in the furcation region. The percentage of bone in the furcation (PBF) was measured. Immunohistochemical analyses for detecting the receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), tartrate-resistant acid phosphatase (TRAP), and activated caspase-3 were performed at the furcation region. RESULTS Compared with the other groups, the SRP/SA group showed less local inflammation and better tissue reparation during the entire experiment. There was more PBF in the SRP/SA group than in the other groups at days 7 and 15. Stronger OPG immunolabeling and weaker RANKL immunolabeling were observed in the SRP/SA group at 15 and 30 days. There were fewer TRAP-positive cells in the SRP/SA group than in the NT group at all of the time points. There was no difference in the number of activated caspase-3-positive osteocytes among groups and time points. CONCLUSION It can be concluded that topical use of SA as an adjuvant to SRP is effective in the treatment of experimental periodontitis.

Experimental periodontal disease treatment by subgingival irrigation with tetracycline hydrochloride in rats

Objective The aim of this study was to compare subgingival irrigation with tetracycline hydrochloride (TTC-HCL) as adjunctive treatment to scaling and root planning (SRP) on induced periodontitis in rats. Material and methods In 60 rats, periodontal disease was ligature-induced at the mandibular left first molar. After 7 days, the ligature was removed and all animals were submitted to SRP, and divided into 2 groups according to the following treatment: C (n=30) - subgingival irrigation with 1 mL of saline; T (n=30) - subgingival irrigation with 1 mL of TTC-HCL (50 mg/mL). Ten animals in each group were euthanized at 7, 15 and 30 days posttreatment. The histometric values were statistically analyzed (p<0.05). Results In the histometric analysis, at 7, 15 and 30 days, Group T (0.72±0.05 mm2, 0.57±0.14 mm2, 0.62±0.07 mm2), showed less bone loss (p<0.05) than Group C (1.35±0.25 mm2; 1.40±0.31 mm2; 1.29±0.27 mm2), respectively. Conclusions Subgingival irrigation with TTC-HCL was an effective adjunctive treatment for periodontal disease induced in rats.

Effect of LLLT on autogenous bone grafts in the repair of critical size defects in the calvaria of immunosuppressed rats.

The aim of this study was to evaluate the effects of low-level laser therapy (LLLT) on the bone repair of critical size defects (CSDs) filled with autogenous bone in the calvaria of immunosuppressed rats. A 5 mm-diameter CSD was created in the calvaria of 30 rats. The animals were divided into 5 groups (n = 6): Control (C)--the defect was filled with a blood clot; Dexamethasone (D)--dexamethasone treatment, and the defect was filled with a blood clot; Autogenous bone (AB)--dexamethasone treatment, and the defect was filled with autogenous bone; LLLT--dexamethasone treatment, and the defect received LLLT (660 nm; 35 mW; 24.7 J/cm(2)); and AB + LLLT--dexamethasone treatment, and the defect was filled with autogenous bone and received LLLT. All animals were euthanized at 30 postoperative days. Histometric and histological analyses were performed. The new bone area (NBA) was calculated as the percentage of the total area of the original defect. Data were analysed statistically (an analysis of variance and Tukeys test; P < 0.05). The AB + LLLT group showed the largest NBA of all groups (P < 0.05). The use of LLLT with AB effectively stimulated bone formation in CSDs in the calvaria of immunosuppressed rats.

Radiographic assessment of photodynamic therapy as an adjunctive treatment on induced periodontitis in immunosuppressed rats

Objective The aim of this study was to assess radiographically the effect of photodynamic therapy (PDT) as an adjunctive treatment to scaling and root planing (SRP) on induced periodontitis in dexamethasone-induced immunosuppressed rats. Material and Methods The animals were divided into 2 groups: ND group (n=60): saline treatment; D group (n=60): dexamethasone treatment. In both ND and D groups, periodontal disease was induced by the placement of a ligature in the left first mandibular molar. After 7 days, ligature was removed and all animals received SRP, being divided according to the following treatments: SRP: saline and PDT: phenothiazinium dye (TBO) plus laser irradiation. Ten animals per treatment were killed at 7, 15 and 30 days. The distance between the cementoenamel junction and the height of the alveolar bone crest in the mesial surface of the mandibular left first molars was determined in millimeters in each radiograph. The radiographic values were analyzed statistically by ANOVA and Tukeys test at a p value <0.05. Results Intragroup radiographic assessment (ND and D groups) showed that there was statistically significant less bone loss in the animals treated with PDT in all experimental periods compared to those submitted to SRP. Intergroup radiographic analysis (ND and D groups) demonstrated that there was greater bone loss in the ND group treated with SRP compared to the D group treated with PDT at 7 and 30 days. Conclusion PDT was an effective adjunctive treatment to SRP on induced periodontitis in dexamethasone-induced immunosuppressed rats.

Recession defects associated with scraped roots treated with subepithelial connective tissue graft.

AbstractThe objective of the current study was to assess histomorphometrically the healing process of recession defects associated with scraped roots treated with subepithelial connective tissue graft (SCTG). Six dogs were used. Bone dehiscence defects (6 × 8 mm) and root planing were carried out on maxillary canine teeth. Following a split-mouth model, according to the treatment, left canines (control) were covered with coronally positioned flap (CPF). Right canines were submitted to treatments with SCTG. After a 3-month postoperative period, the animals were killed, and the blocks processed for the histomorphometric assessment. Data assessment demonstrated that the CPF group showed parameters of a new connective tissue attachment, length of new cement (NC), length of new bone (mean ± SD: 0.95 ± 0.53, 2.44 ± 1.97, and 1.96 ± 2.29 mm, respectively), which were higher than those of SCTG group (mean ± SD: 0.71 ± 0.36, 2.21 ± 1.28, and 1.52 ± 1.31 mm, respectively), although not significantly (P > 0.05). The length of both epithelial tissue and connective tissue apposition in the SCTG group (mean ± SD: 1.70 ± 0.53 and 2.62 ± 1.52 mm, respectively) were higher than those of the CPF group (mean ± SD: 1.18 ± 0.49 and 2.03 ± 1.03 mm, respectively), although showing no significant differences (P > 0.05). Within the limits of the current study, it was possible to conclude that there were no significant differences between the groups according to the histologic parameters assessed.

Obtenção da fase peroviskita via microemulsão

The present work focuses on the synthesis of small particles of the perovskite phase of BaMnO3 through the route of conventional coprecipitation (RCC) and the method of conventional microemulsion (MCM). The techniques used for samples characterization were: scanning electron microscopy (SEM), X-ray diffraction patterns (XRD), thermogravimetry (TG) and differential thermal analysis (DTA). The synthesis of materials in self-organized colloidal system has as main objective to increase the shape and size homogeneity of the particles. In the last years it has been intensified the search for more homogeneous materials. The microemulsion route is an alternative method for the synthesis of more homogeneous material because it allows for controlling the relationship of water to surfactante concentrations, (w), which controls the average size of the microemulsion drops. Pure perovskite BaMnO3 phase obtained from microemulsion appears at smaller temperature than the precipitated one, and results in a better size distribution of the particles, around 0,1 mm in diameter compared to 0,5 mm obtained by coprecipitation.