Effectiveness of the diode laser in the treatment of ligature-induced periodontitis in rats: a histopathological, histometric, and immunohistochemical study

The aim of this study was to evaluate the effects of the use of a high-power gallium-aluminum-arsenide diode laser (GaAlAs; 808 nm, 1 W, 20 s, 20 Hz, 10 J) alone or as adjunctive therapy to scaling and root planing in the treatment of induced periodontitis in rats. Periodontitis was induced by placing a ligature around the mandibular first molar of 60 rats. After 7 days, the ligature was removed and the animals were divided into four groups as follows: C (control), no periodontal treatment; SRP, scaling and root planing (SRP); DL, diode laser (DL) irradiation treatment; and SRP/DL, both SRP and DL irradiation treatment. Five animals from each group were euthanized at 7, 15, and 30 days posttreatment. The effectiveness of the treatments was evaluated in the furcation area using histopathological analysis, histometric analysis of alveolar bone loss (ABL), and immunohistochemical detection of tartrate-resistant acid phosphatase (TRAP), runt-related transcription factor 2 (RUNX2), and osteocalcin (OCN). DL, alone or in combination with adjunctive therapy to SRP in the treatment of experimental periodontitis, resulted in a decreased local inflammatory response. At 7-days posttreatment, the DL and SRP/DL groups had fewer TRAP-positive cells and more RUNX2-positive cells. There was greater OCN immunolabeling in the DL group than in the C and SRP groups at 15 days. There was less ABL in the DL and SRP/DL groups at 15 and 30 days. In conclusion, DL was effective in the treatment of ligature-induced periodontitis in rats, both when used alone and when used as adjunctive therapy to SRP.

Evaluation of the progression and treatment of experimental periodontitis in rats subjected to chemotherapy with 5-fluorouracil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Clinical Influence of Different Intracanal Medications on Th1-type and Th2-type Cytokine Responses in Apical Periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antimicrobial photodynamic therapy as an adjunct to non-surgical treatment of aggressive periodontitis: a split-mouth randomized controlled trial

Background: The management of aggressive periodontitis (AgP) represents a challenge for clinicians because there are no standardized protocols for an efficient control of the disease. This randomized controlled clinical trial evaluated the effects of repeated applications of antimicrobial photodynamic therapy (aPDT) adjunctive to scaling and root planing (SRP) in patients with AgP. Methods: Using a split-mouth design, 20 patients with generalized AgP were treated with aPDT + SRP (test group) or SRP only (control group). aPDT was applied at four periods. All patients were monitored for 90 days. Clinical, microbiologic, and immunologic parameters were statistically analyzed. Results: In deep periodontal pocket analysis (probing depth [PD] >= 7 mm at baseline), the test group presented a decrease in PD and a clinical attachment gain significantly higher than the control group at 90 days (P < 0.05). The test group also demonstrated significantly less periodontal pathogens of red and orange complexes and a lower interleukin-1 beta/interleukin-10 ratio than the control group (P < 0.05). Conclusion: The application of four sessions of aPDT, adjunctive to SRP, promotes additional clinical, microbiologic, and immunologic benefits in the treatment of deep periodontal pockets in single-rooted teeth in patients with AgP.

Clopidogrel enhances mesenchymal stem cell proliferation following periodontitis

Bone formation is dependent on the differentiation of osteoblasts from mesenchymal stem cells (MSCs). In addition to serving as progenitors, MSCs reduce inflammation and produce factors that stimulate tissue formation. Upon injury, MSCs migrate to the periodontium, where they contribute to regeneration. We examined the effect of clopidogrel and aspirin on MSCs following induction of periodontitis in rats by placement of ligatures. We showed that after the removal of ligatures, which induces resolution of periodontal inflammation, clopidogrel had a significant effect on reducing the inflammatory infiltrate. It also increased the number of osteoblasts and MSCs. Mechanistically, the latter was linked to increased proliferation of MSCs in vivo and in vitro. When given prior to inducing periodontitis, clopidogrel had little effect on MSC or osteoblasts numbers. Applying aspirin before or after induction of periodontitis did not have a significant effect on the parameters measured. These results suggest that clopidogrel may have a positive effect on MSCs in conditions where a reparative process has been initiated.

Exenatide and sitagliptin decrease interleukin 1β, matrix metalloproteinase 9, and nitric oxide synthase 2 gene expression but does not reduce alveolar bone loss in rats with periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Correlation between volume of apical periodontitis determined by cone-beam computed tomography analysis and endotoxin levels found in primary root canal infection

This clinical study was conducted to correlate the levels of endotoxins and bacterial counts found in primary endodontic infection with the volume of periapical bone destruction determined by cone-beam computed tomography (CBCT) analysis. Moreover, the levels of bacteria and endotoxins were correlated with the development of clinical features. Twenty-four root canals with primary endodontic disease and apical periodontitis were selected. Clinical features such as pain on palpation, pain on percussion, and previous episode of pain were recorded. The volume (cubic millimeters) of periapical bone destruction was determined by CBCT analysis. Endotoxins and bacterial samplings were collected by using sterile/apyrogenic paper points. Endotoxins were quantified by using limulus amebocyte lysate assay (KQCL test), and bacterial count (colony-forming units [CFU]/mL) was determined by using anaerobic culture techniques. Data were analyzed by Pearson correlation and multiple logistic regression (P < .05). Endotoxins and bacteria were detected in 100% of the root canal samples (24 of 24), with median values of 10.92 endotoxin units (EU)/mL (1.75-128 EU/mL) and 7.5 × 10(5) CFU/mL (3.20 × 10(5)-8.16 × 10(6) CFU/mL), respectively. The median volume of bone destruction determined by CBCT analysis was 100 mm(3) (10-450 mm(3)). The multiple regression analysis revealed a positive correlation between higher levels of endotoxins present in root canal infection and larger volume of bone destruction (P < .05). Moreover, higher levels of endotoxins were also correlated with the presence of previous pain (P < .05). Our findings revealed that the levels of endotoxins found in root canal infection are related to the volume of periapical bone destruction determined by CBCT analysis. Moreover, the levels of endotoxin are related to the presence of previous pain.

Effect of the probiotic Saccharomyces cerevisiae on ligature-induced periodontitis in rats

This study assessed the effects of the local use of Saccharomyces cerevisiae as monotherapy and as an adjuvant to the mechanical treatment of ligature-induced periodontitis in rats. Periodontitis was induced in 72 rats via the installation of a ligature around the mandibular first molar. After 7 d, the ligature was removed and the rats were placed in one of the following groups: no treatment (C; n = 18); scaling and root planing (SRP; n = 18); local irrigation with probiotics (PRO; n = 18); and SRP followed by local irrigation with probiotics (SRP/PRO; n = 18). Six rats from each group were killed at 7, 15 and 30 d. The histological characteristics, alveolar bone loss (ABL) and immunolabeling of tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β), interleukin-10 (IL-10) and TRAP on the furcation area of the first molar were assessed. The PRO group showed features of acceleration of the tissue-repair process during the entire experiment. On day 15, there was less ABL in the SRP/PRO group compared with the C group. There were fewer TRAP-positive cells in the SRP and SRP/PRO groups at 30 d. There was less immunostaining for TNF-α in the PRO and SRP/PRO groups and less immunostaining for IL-1β in the PRO group. However, there was more immunostaining for IL-10 in the PRO group on day 15. Local use of the probiotic did not result in any adverse effects on periodontal tissues. When used as monotherapy or as an adjuvant, the probiotic was effective at controlling periodontitis in rats.

Down-regulation of protease activated receptor 2, interleukin-17 and other pro-inflammatory genes by subantimicrobial doxycycline dose in a rat periodontitis model

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of irrigation and intracanal dressing on the healing process of dogs' teeth with apical periodontitis.

Dogs' teeth with apical periodontitis were treated endodontically, Dakin's solution being used in an experimental group as the irrigation solution, and camphorated paramonochlorophenol as an intracanal dressing. For a second group of teeth, the irrigation solution used was physiologic saline, dry cotton only being placed into the pulpal chamber to take the place of an intracanal dressing. In a second visit, overinstrumentation and a new application of the same kind of dressing were performed, the root canals being then filled with gutta-percha cones and zinc oxide-eugenol cement. Other specimens were treated, in one visit, where physiologic saline or Dakin's solution were the irrigation solutions. The animals were sacrificed 6 months after the obturation of the root canals. Histologic exams showed better results for the experimental group where Dakin's solution and camphorated paramonochlorophenol had been used, with signs of repair characterized by newly formed cementum and bone tissue, as well as a marked reduction in size of the periapical lesions. No differences were seen in the results with physiologic saline or Dakin's solution as irrigants.

Radiographic assessment of potodynamic therapy as an adjunctive treatment on induced periodontitis in immunosupressed 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. he radiographic values were analyzed statistically by ANOVA and Tukey's test at a p value <0.05. RESULTS: Intragroup radiographic assessment (ND and D groups) showed that there was statistically signifcant 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.

Adjuvant therapy with sodium alendronate for the treatment of experimental periodontitis in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antimicrobial susceptibility to b-lactams and metronidazole of microorganisms isolated from chronic and aggressive periodontitis

The objective of this study was to evaluate the microbial susceptibility to ß-lactams and metronidazole, and evaluate the production of ß-lactamases by microorganisms isolated from patients with chronic or aggressive periodontitis. The samples were obtained from 50 patients with periodontitis and microorganisms were isolated onto selective and nonselective culture media, identified by biochemical methods and tested for susceptibility to antimicrobial agents (amoxicillin, amoxicillin/clavulanate, cefoxitin, imipenem, metronidazole, penicillin G). The isolates were resistant to at least 1 mg/ml of any drug tested were evaluated to verify the production of ß-lactamases by the method of double layer (or biological) and chromogenic cephalosporin using nitrocefin. The results evidenced resistance to amoxicillin and penicillin G, while the susceptibility to association amoxicillin/clavulanate, imipenem and cefoxitin was widely disseminated among the organisms. Resistance to these drugs showed a clear correlation with the production of ß-lactamase in the majority of microbial groups.

In vitro antifungal susceptibility of candida albicans isolates from patients with chronic periodontitis and diabetes

Alterations that lead to deficiency of the immune system, such as diabetes mellitus, may promote proliferation of Candida albicans and selection of strains which have greater ability to adhere and to penetrate the host tissues. Recent studies indicate an increase of the antifungal resistance of C. albicans isolates in periodontal pockets, suggesting that the oral cavity could be a reservoir of resistant yeast to antifungal agents. Moreover, oral cavity can act as a reservoir of certain pathogens that may cause systemic infections. The periodontal pocket is an ecological niche suitable to host microorganisms that could act as opportunistic pathogens. The aim of this study is to contribute to the understanding of resistance to conventional antifungal against C. albicans isolates from patients with periodontitis and diabetes. The determination of the minimal inhibitory concentrations (MIC) was evaluated according to M27S3 of the CLSI (2008), with modifications. The results showed that 48.8% of the studied strains were resistant to one or more antifungals and 6.6% were resistant to fluconazole and voriconazole. These results suggest an increasing resistance to conventional antifungal agents among Candida species, suggesting that the oral cavity could host pathogen fungi.

The role of obesity as a modifying factor in patients undergoing non-surgical periodontal therapy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)