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.
Background and Objective
Antimicrobial therapy can suppress periodontal pathogens and increase the effectiveness of conventional mechanical treatment. The aim of this study was to assess bone loss ...and the immune inflammatory response of rats under the influence of two photosensitizing agents (MB and TBO) at two different concentrations in antimicrobial photodynamic therapy (aPDT), used as an adjuvant therapy in the treatment of periodontitis.
Material and Methods
Periodontitis was induced in the mandibular first molars of 162 rats. The animals were divided into nine groups: G1 – scaling and root planing (SRP); G2 – SRP plus 100 μg/mL of methylene blue (MB); G3 – SRP plus 10 mg/mL of MB; G4 – SRP plus 100 μg/mL of toluidine blue (TBO); G5 – SRP plus 10 mg/mL of TBO; G6 – SRP plus 100 μg/mL of MB and laser; G7 – SRP plus 10 mg/mL of MB and laser; G8 – SRP plus 100 μg/mL of TBO and laser; and G9 – SRP plus 10 mg/mL of TBO and laser. Six animals from each group were euthanized 7, 15, or 30 d after treatment. Bone loss (BL) in the furcation region was evaluated using histomorphometric and immunohistochemical analyses to detect the receptor activator of nuclear factor‐Κappa B ligand (RANKL), osteoprotegerin (OPG) and tartrate‐resistant acid phosphatase (TRAP).
Results
There was significantly less BL in animals treated with aPDT using low concentrations of MB and TBO at 7, 15 and 30 d. Immunohistochemical analysis revealed decreased RANKL and increased OPG in the aPDT groups and decreased TRAP‐positive cells in G6 and G8.
Conclusions
aPDT, using low concentrations of MB and TBO, was the most effective adjuvant therapy to SRP, acting indirectly as a downregulator of the molecular mechanisms that control bone resorption in periodontitis.
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 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.
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 investigate the effects of liver fibrosis (LF) on the pro‐inflammatory mediators and periapical bone resorption of apical periodontitis (AP) in rats.
Methodology
Forty male Wistar rats were ...distributed into four groups: C – control, AP – rats with AP, LF – rats with LF, AP + LF – rats with AP and LF. LF was induced by carbon tetrachloride administration for 8 weeks and surgical bile duct ligation for 4 weeks; AP was induced in the teeth of rats by dental pulp exposure to the oral environment for 30 days. Jaws and livers were removed after euthanasia. Haematoxylin and Eosin (H&E) and Picrosirius Red (PSR) staining were used to confirm fibrosis in the livers. The jaws were analysed using H&E staining, immunohistochemical assays of interleukin (IL)‐1β, IL‐6 and tumour necrosis factor‐alpha (TNF‐α). Student’s t‐test and Mann–Whitney’s U‐test were used for statistical analysis (P < 0.05).
Results
Inflammatory infiltrate was moderate in the AP group and severe in the AP + LF group (P < 0.05). Periapical bone resorption was significantly larger in the AP + LF group compared with the AP group (P < 0.05). IL‐1β, IL‐6 and TNF‐α levels were significantly higher in AP + LF group when compared to the AP group (P < 0.05).
Conclusion
More intense inflammatory infiltrate, greater amounts of pro‐inflammatory cytokines and increased periapical bone resorption were observed in the presence of liver fibrosis in rats with exposed pulps.
Aim
To evaluate the influence of tooth bleaching on immunoregulatory cytokines production (IL‐6, Tumour necrosis factor (TNF)‐α and IL‐17) in the pulp tissue of normoglycaemic and diabetic rats.
...Methodology
Twenty‐eight rats were divided into normoglycaemic and diabetic rats (n = 14). Diabetes mellitus (DM) was induced with a single dose of alloxan diluted in citrate buffer via intramuscular injection. After DM confirmation, all rats were sedated and tooth bleaching was performed using 35% hydrogen peroxide on the right maxillary molars for 30 min. Left molars were used as controls. Bleaching resulted in four hemimaxillae groups: normoglycaemic (N), N‐bleached (NBle), diabetic (D) and D‐bleached (DBle). After 2 and 30 days, rats were euthanized and hemimaxillae processed for analysis by haematoxylin and eosin and immunohistochemistry. Results within and between animals were submitted to Wilcoxon signed‐rank and Mann–Whitney tests (P < 0.05).
Results
At 2 days, the NBle group had mild, and the DBle had severe inflammatory infiltration in the pulpal tissue (P < 0.05). TNF‐α and IL‐6 cytokines were associated with increased immunolabelling in the bleached groups compared to nonbleached (P < 0.05). However, IL‐17 had increased immunolabelling in the NBle compared to the N and DBle group (P < 0.05). At 30 days, reactionary dentine was observed in the coronal pulp of all bleached teeth and no inflammation was present (P > 0.05). TNF‐α cytokines had increased immunolabelling in the DBle group compared to the D group (P < 0.05). However, for IL‐6 and IL‐17, no difference was observed in this period (P > 0.05).
Conclusions
Tooth bleaching increased IL‐6 and TNF‐α in the pulp tissue regardless of diabetes mellitus; however, diabetic rats had higher TNF‐α levels for longer periods. Tooth bleaching influenced the increase in IL‐17 in the early periods in normoglycaemic rats.
Aim
To investigate whether hypertension affects mineralization associated with white and grey mineral trioxide aggregate (MTA Angelus®) implanted subcutaneously into rats by assaying osteoblastic ...biomarkers.
Methodology
Polyethylene tubes containing grey MTA Angelus®, white MTA Angelus®, intermediate restorative material (IRM; positive control) or an empty tube (negative control) were implanted into the dorsal connective tissue of spontaneous hypertensive (n = 12) and Wistar (normotensive; n = 10) rats. Half of the rats in each group were killed after 7 days, and the remaining after 30 days. Tubes with surrounding tissue were removed, and immunostaining was performed to detect RUNX‐2, OPN and OCN proteins. The normality of data was analysed using the Shapiro–Wilk test. Comparison of two independent groups was performed using the Mann–Whitney U‐test, to detect a significant difference. A post hoc test accounting for multiple comparisons was performed following Tukey's test (P < 0.05).
Results
Under hypertensive conditions after 30 days, both MTA materials were associated with immunolabelling for RUNX‐2 from low to moderate, which was less than that observed at normal blood pressure and the 7‐day groups (P < 0.05). The expression of OPN and OCN proteins under both MTA conditions was considered low after both 7 and 30 days for the hypertensive condition, and was less than that in animals with normal blood pressure after 30 days (P < 0.05). No immunostaining for any biomarkers in the control and IRM groups was observed (P < 0.05).
Conclusion
Hypertension decreased the immunostaining of RUNX‐2, OPN and OCN biomarkers in response to MTA. Thus, hypertension can jeopardize the mineralization ability of MTA and may have a negative impact on endodontic treatment outcomes.
Teneurins are transmembrane proteins consisting of four paralogues (Ten-1-4), notably expressed in the central nervous system during development. All teneurins contain a bioactive peptide in their ...carboxyl terminal named teneurin C-terminal associated peptide (TCAP). The present study analyzed the detailed distribution of teneurin-2-like immunoreactive (Ten-2-LI) cells in developing and mature rat molar teeth, as well as in mature human dental pulps. Ten-2 and TCAP-2 genic expressions were also evaluated in rat and human dental pulps. Finally, Ten-2-LI cells were analyzed during the repair process after dentin-pulp complex injury in rat lower molar teeth. For this, histological sections of rat molar teeth and human dental pulps were submitted to immunohistochemical techniques, while total RNA from developing rat teeth and mature human dental pulps were submitted to conventional RT-PCR. Ten-2-LI cells were evident in the initial bell stage of rat molar teeth development, especially in ectomesenchymal cells of the dental papilla. Ten-2-LI odontoblasts showed strong immunoreactivity in rat and human mature teeth. Ten-2 and TCAP-2 genic expressions were confirmed in rat and human dental pulps. Dentin-pulp complex injury resulted in a decrease of Ten-2-LI odontoblasts after traumatic injury. Interestingly, Ten-2-LI cells were also evident in the pulp cell-rich zone in all postoperative days. In conclusion, Ten-2-LI presence in rat and human odontoblasts was demonstrated for the first time and Ten-2/TCAP-2 genic expressions were confirmed in rat and human dental pulps. Furthermore, it was revealed that Ten-2-LI rat odontoblasts can be modulated during the regenerative process.
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