The development of biomaterials based on the combination of biopolymers with bioactive compounds to develop delivery systems capable of modulating dentin regeneration mediated by resident cells is ...the goal of current biology-based strategies for regenerative dentistry. In this article, the bioactive potential of a simvastatin (SV)–releasing chitosan-calcium-hydroxide (CH-Ca) scaffold was assessed. After the incorporation of SV into CH-Ca, characterization of the scaffold was performed. Dental pulp cells (DPCs) were seeded onto scaffolds for the assessment of cytocompatibility, and odontoblastic differentiation was evaluated in a microenvironment surrounded by dentin. Thereafter, the cell-free scaffold was adapted to dentin discs positioned in artificial pulp chambers in direct contact with a 3-dimensional (3D) culture of DPCs, and the system was sealed to simulate internal pressure at 20 cm/H2O. In vivo experiments with cell-free scaffolds were performed in rats’ calvaria defects. Fourier-transform infrared spectroscopy spectra proved incorporation of Ca and SV into the scaffold structure. Ca and SV were released upon immersion in a neutral environment. Viable DPCs were able to spread and proliferate on the scaffold over 14 d. Odontoblastic differentiation occurred in the DPC/scaffold constructs in contact with dentin, in which SV supplementation promoted odontoblastic marker overexpression and enhanced mineralized matrix deposition. The chemoattractant potential of the CH-Ca scaffold was improved by SV, with numerous viable and dentin sialoprotein–positive cells from the 3D culture being observed on its surface. Cells at 3D culture featured increased gene expression of odontoblastic markers in contact with the SV-enriched CH-Ca scaffold. CH-Ca-SV led to intense mineralization in vivo, presenting mineralization foci inside its structure. In conclusion, the CH-Ca-SV scaffold induces differentiation of DPCs into a highly mineralizing phenotype in the presence of dentin, creating a microenvironment capable of attracting pulp cells to its surface and inducing the overexpression of odontoblastic markers in a cell-homing strategy.
Aim
To verify the effects of melatonin supplementation on insulin sensitivity, plasma concentrations of inflammatory cytokines, insulin signalling and inflammatory pathways in the soleus (SM) and ...extensor digitorum longus (EDL) muscles of rats with apical periodontitis (AP).
Methodology
Seventy‐two Wistar rats were distributed into 4 groups: (a) control (C), (b) control supplemented with melatonin (M), (c) AP (AP), and (d) AP supplemented with melatonin (AP + M). AP was induced by pulp exposure of the maxillary and mandibular right first and second molars to the oral environment. After AP induction, oral supplementation with 5 mg kg−1 melatonin (diluted in drinking water) for 60 days was initiated. At the end of the treatment, the following were analysed: (1) plasma concentrations of insulin and inflammatory cytokines (TNF‐α, IL‐6, IL‐1β and IL‐10) using ELISA kits; (2) glycaemia using enzymatic assay; (3) insulin resistance using homoeostasis model assessment of insulin resistance (HOMA‐IR) index; and (4) phosphorylation status of pp185 tyrosine, Akt serine, IKKα/β, and JNK in SM and EDL using Western blot. Analysis of variance of two or three factors was performed, followed by the Bonferroni test. P values < 0.05 were considered statistically significant.
Results
AP promoted insulin resistance, significantly increased (P < 0.05) plasma concentrations of pro‐inflammatory cytokines (TNF‐α, IL‐6, and IL‐1β), significantly decreased (P < 0.05) the concentration of anti‐inflammatory cytokine IL‐10, impaired insulin signalling in SM, and increased IKKα/β phosphorylation status in SM and EDL. Melatonin supplementation in rats with AP improved insulin sensitivity, significantly decreased (P < 0.05) TNF‐α and IL‐1β, significantly increased (P < 0.05) IL‐10 plasma concentrations, and changed the insulin signalling in soleus muscle and IKKα/β phosphorylation status in SM and EDL muscles.
Conclusions
Melatonin is a potent adjuvant treatment for improving apical periodontitis‐associated changes in insulin sensitivity, insulin signalling and inflammatory pathways. In addition, the negative impact of AP on general health was also demonstrated.
Aim
To investigate the effect of chronic alcohol consumption on apical periodontitis in rats.
Methodology
Thirty‐two male Wistar rats were arranged into four groups: Control (C): without apical ...periodontitis and nonalcoholic diet; (AL): without apical periodontitis and alcoholic diet; (AP): with apical periodontitis and nonalcoholic diet; and (AP + AL): with apical periodontitis and alcoholic diet. The alcoholic solution at 20% was given to the AL and AP + AL groups as the sole source of hydration throughout the experiment. AP was induced in the mandibular left first molars at the end of the 4th week. Weight changes and the amount of solid and liquid foods were recorded for 8 weeks. At the end, the animals were euthanized and the jaws removed followed by histological processing for histopathological and RANKL, OPG, TRAP and HIF‐1α analyses. The Mann–Whitney test was used for nonparametric data, and anova followed by the Tukey test was performed for parametric data, with P < 0.05.
Results
Animals that received the alcoholic diet had a lower weight gain than the other groups (P < 0.05). Control and AL groups did not have an inflammatory response in the periapical tissues. The median score of inflammatory infiltrate was significantly higher in the AP + AL group (2.5) compared to the AP group (1.5; P < 0.05). In the same comparison, AP + AL was associated with score 3 for RANKL and HIF‐1α versus score 2 for AP group (P < 0.05). Moreover, the values for TRAP were 3.88 ± 0.70 cells mm−1 for the AP + AL group and 2.43 ± 0.94 cells mm−1 for the AP group (P < 0.05).
Conclusion
In rats, an alcoholic diet had a significant effect on the severity of apical periodontitis, exacerbating the inflammatory response and osteoclastogenesis.
Aim
To investigate the relationship between apical periodontitis and atherosclerosis in rats by lipid profile and carotid artery intima tunic measurement, and histological and histometric evaluation ...of periapical lesions.
Methodology
Forty male Wistar rats were allocated into four groups: control (C), with apical periodontitis (AP), with atherosclerosis (AT) and with AP and AT (AP + AT). Atherosclerosis was induced using a high‐lipid diet associated with a surgical ligature in the carotid artery and a super dosage of vitamin D3. AP was induced via pulp exposure to the oral environment. At 45 and 75 days, serum levels of total cholesterol (TC), triglycerides (TG), high‐density lipoprotein cholesterol (HDL‐C) and low‐density lipoprotein cholesterol (LDL‐C) were measured. The maxillary and mandibular jaws and carotid artery were collected and processed for histological analysis. The Kruskal–Wallis or Mann–Whitney test was performed for nonparametric data, and the Tukey’s or Student’s t‐test was performed for parametric data (P < 0.05).
Results
In nonatherosclerotic animals, the induction of apical periodontitis increased TG levels significantly, from 63.1 ± 11.4 mg dL−1 in group C to 88.2 ± 7.9 mg dL−1 in the AP group (P < 0.05). The induction of AP was associated with a trend for higher TC and LDL‐C levels in atherosclerotic animals (P > 0.05); however, it only significantly increased TG levels, from 93.2 ± 18.0 mg dL−1 in AT group to 121.9 ± 14.5 mg dL−1 in the AP + AT group (P < 0.05). Animals in the AP + AT group had a 36.5% increase in the thickness of the carotid intima tunic when compared with the AT group (P < 0.05). The intensity of the inflammatory infiltrate was significantly larger in the AP + AT group when compared with AP group (P < 0.05). The AP + AT group exhibited significantly greater alveolar bone loss, with a periapical lesion size of 206.4 ± 56.3 × 104 μm2, compared with 151.4 ± 49.1 × 104 μm2 in the AP group (P < 0.05).
Conclusion
Apical periodontitis influenced triglyceride levels, increasing them even in the absence of atherosclerosis, and influenced the increase in the thickness of the carotid artery intima tunic in the presence of atherosclerosis. Atherosclerosis intensified the inflammatory reaction and increased bone resorption in periapical lesions.
The aim of this review was to examine current knowledge of the role of interleukin‐6 (IL‐6) in apical periodontitis (AP) pathogenesis as an inflammatory or pro‐inflammatory cytokine. It also looked ...at whether IL‐6 could serve as a measure for differential diagnosis or as a biomarker that can further predict the progression of bone resorption. A systematic review relating to AP and IL‐6 was made via PubMed, BIOSIS, Cochrane, EMBASE and Web of Science databases using keywords and controlled vocabulary. Two independent reviewers first screened titles and s and then the full texts. The reference lists of the identified publications were examined for additional titles. Eighteen papers were studied in total. In vitro studies (n = 6) revealed that IL‐6 is present in AP, and its levels are proportional to the size of the periapical lesions. Neutrophils and macrophages resident in these lesions can produce IL‐6 in vitro after a bacterial stimulus. Animal studies (n = 5) showed that IL‐6 is present in AP and that osteoblasts can produce IL‐6 in vivo. On the other hand, two studies using IL‐6 knockout mice revealed larger periapical lesions when compared with control groups, demonstrating IL‐6's role as an anti‐inflammatory cytokine. In human studies (n = 7), IL‐6 was identified in AP, and its levels were higher in symptomatic, epithelialized and large lesions than in asymptomatic and small lesions. These data lead to the conclusion that IL‐6 may play a pro‐inflammatory role, increasing its levels and reabsorbing bone in the presence of infections. When IL‐6 is not present, other cytokines such as IL‐1 and TNF‐α induce bone resorption. Further studies about the relationship between AP development and the cytokine network must be performed to establish the exact role of each cytokine in the inflammatory process.
Aim
To evaluate the inflammatory response and ability to induce mineral deposition through histological and immunohistochemical analysis for osteocalcin (OCN), osteopontin (OPN) and bone sialoprotein ...(BSP) of a new calcium silicate‐based cement, Bio‐C Pulpo (Angelus), compared to white mineral trioxide aggregate (White MTA‐Ang) (Angelus).
Methodology
Polyethylene tubes containing Bio‐C Pulpo and White MTA‐Ang as well as empty tubes were implanted into the dorsal connective tissue of 30 Wistar rats, which were arranged in five groups according to the period of analysis: 7, 15, 30, 60 and 90 days. After each experimental period, the tubes with surrounding tissue were removed and histologically processed to be analysed using haematoxylin–eosin and immunohistochemistry for the detection of OCN, OPN and BSP. The data were statistically analysed (Friedman's test) at a 5% significance level.
Results
The inflammatory response observed with Bio‐C Pulpo and White MTA‐Ang was greater after 7 and 15 days and decreased from 30 days onwards. No significant difference was found between the control, Bio‐C Pulpo and White MTA‐Ang at the different periods of analysis (P > 0.05). The immunolabelling for OCN, OPN and BSP was more intense for Bio‐C Pulpo and White MTA‐Ang after 60 and 90 days, but there was no difference between Bio‐C Pulpo and White MTA‐Ang at the different periods of analysis (P > 0.05).
Conclusion
Bio‐C Pulpo is biocompatible and induces immunolabelling of osteogenic markers such as OCN, OPN and BSP similar to White MTA‐Ang.
Aim
To evaluate the effect of systemic administration of probiotics on the severity of apical periodontitis (AP).
Methodology
Twenty‐four male Wistar rats were used. AP was induced in the maxillary ...left/right first molars. The animals were arranged into groups: Control, Lactobacillus rhamnosus, and Lactobacillus acidophilus. Probiotics were administered orally for gavage (109 colony‐forming units diluted in 5 mL of water for 30 days) during the development of AP. After 30 days, cardiac puncture was performed to analyse the complete blood count. Moreover, microbiological analysis of the root canal contents and saliva was performed. Then, the animals were euthanized and the jaw removed for histopathological and IL‐10, IL‐1β and IL‐6 immunolabeling analyses. After the Shapiro–Wilk test of normality, the Kruskal–Wallis followed by Dunn's test was performed for nonparametric data, and analysis of variance followed by the Tukey test was performed for parametric data (P < 0.05).
Results
No significance difference was observed in the blood profiles and in the counts of microorganisms from the saliva samples among the groups (P > 0.05). Total microorganism counts in the root canal, the inflammatory infiltrate and the immunostaining for IL‐1β and IL‐6 in AP were significantly lower in the probiotic groups when compared with the control group (P < 0.05). IL‐10 was significantly more immunolabled in the probiotic groups than in the control group (P < 0.05).
Conclusion
Supplementation with probiotics (Lactobacillus rhamnosus and Lactobacillus acidophilus) had a significant effect on the severity of apical periodontitis in rats, demonstrating the anti‐inflammatory effect of probiotics on the development of apical periodontitis.
Aim
To evaluate lymphocyte‐like cell activation (CD5‐positive cells) and the expression of interleukin (IL)‐6 and IL‐17 in the pulp after tooth bleaching with two concentrations of hydrogen peroxide ...(H2O2).
Methodology
The right and left maxillary molars from 40 rats were treated randomly with bleaching gel with 20% H2O2 (BLUE group, 1 application of 50 min), 35% H2O2 (MAXX group, three applications of 15 min), or placebo gel (control). After 2 and 30 days, the rats were killed (n = 10), and the jaws were processed for histological and immunohistochemistry analysis of the pulp tissue. The scores of inflammation and immunolabelling (IL‐6/IL‐17) were submitted to Mann–Whitney and Kruskal–Wallis followed Dunn tests, respectively; anova tests were used for comparisons of number of CD5‐positive cells and pulp chamber area values (P < 0.05).
Results
At 2 days, 60% of specimens of the BLUE group were associated with moderate inflammation in pulp horns, and in the MAXX group with necrosis (P < 0.05). At 30 days, the pulp was organized, and tertiary dentine was formed. The MAXX group had superior immunolabelling of IL‐17 at 2 days differing significantly from other groups (P < 0.05). At 2 days, 90% of the specimens of the BLUE group had moderate immunolabelling of IL‐6, and 50% of the MAXX group had severe immunolabelling, both significantly different from the control (P < 0.05). There was no significant difference between the groups at 30 days (P > 0.05). CD5‐positive cells were present at 2 and 30 days, particularly in the bleached groups (P < 0.05), without significant difference between time periods (P > 0.05).
Conclusions
IL‐6 and IL‐17 participated in inflammation in the pulp tissue of rats after tooth bleaching, particularly at 2 days. The immunolabelling was greater with increasing H2O2 concentration. This process was accompanied by the prolonged activation of CD5‐positive cells.
Aim
To evaluate the relationship between systemic administration of probiotics and inflammation/resorption processes associated with apical periodontitis (AP) in a rat model.
Methodology
Twenty‐four ...male Wistar rats were used. AP was induced in the mandibular left/right first molars. The animals were arranged into three groups: Control, Lactobacillus rhamnosus and L. acidophilus. Probiotics were orally administered via gavage (109 colony‐forming units (CFU) diluted in 5 mL of water) for 30 days during the development of AP. On the 30th day, blood was collected to analyse the calcium, phosphorus and alkaline phosphatase concentrations in plasma. Then, the animals were euthanized and the jaws removed for micro‐computed tomography and immune‐histopathological analysis for receptor activator of NF‐κB ligand (RANKL), osteoprotegerin (OPG) and tartrate‐resistant acid phosphatase (TRAP). After the Shapiro–Wilk test of normality, the Kruskal–Wallis followed by Dunn’s test was performed for nonparametric data, and analysis of variance followed by the Tukey test was performed for parametric data (P < 0.05).
Results
There was no significant difference in the calcium and phosphorus levels in plasma amongst the groups (P > 0.05). The level of alkaline phosphatase was significantly higher in the groups that consumed probiotics (P < 0.05). A significantly lower volume of bone resorption was observed in groups that consumed probiotics (P < 0.05). The inflammatory infiltrates and the immunolabelling for RANKL and TRAP were significantly lower in probiotic groups when compared to the control (P < 0.05). Also, the OPG was significantly more immunolabelled in the L. acidophilus group than in the L. rhamnosus and control groups (P < 0.05).
Conclusion
Probiotic supplementation through gavage (L. rhamnosus and L. acidophilus) had a significant effect on the reduction of inflammation and bone resorption in apical periodontitis development in rats.
This study's aim was to evaluate the degradation rate of hydrogen peroxide (H2O2) and to quantify its penetration in tooth structure, considering the residence time of bleaching products on the ...dental enamel. For this study, bovine teeth were randomly divided according to the bleaching product received: Opalescence Xtra Boost 38%, White Gold Office 35%, Whiteness HP Blue 35%, Whiteness HP Maxx 35%, and Lase Peroxide Sensy 35%. To analyze the degradation of H2O2, the titration of bleaching agents with potassium permanganate was used, while the penetration of H2O2 was measured via spectrophotometric analysis of the acetate buffer solution, collected from the artificial pulp chamber. The analyses were performed immediately as well as 15 minutes, 30 minutes, and 45 minutes after product application. The data of degradation rate of H2O2 were submitted to analysis of variance (ANOVA) and Tukey tests, while ANOVA and Fisher tests were used for the quantification of H2O2, at the 5% level. The results showed that all products significantly reduced the concentration of H2O2 activates at the end of 45 minutes. It was also verified that the penetration of H2O2 was enhanced by increasing the residence time of the product on the tooth surface. It was concluded that the bleaching gels retained substantial concentrations of H2O2 after 45 minutes of application, and penetration of H2O2 in the dental structure is time-dependent.
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