Search

Aim: To quantify M1 and M2 macrophages in radicular cysts of permanent (n = 14 cases) and primary teeth (n = 15 cases). Methodology: All patients who attended the School of Dentistry Ribeirão Preto, University of São Paulo with primary teeth or permanent molars that were scheduled for extraction and fulfilled the inclusion criteria: absence of pain; presence/absence of fistulae; extensive coronal destruction due to caries lesions without possibility of restoration; pulp necrosis; radiographically visible apical periodontitis; and no previous treatment, were selected. The radicular cysts were removed and subsequently submitted to histopathologic analysis in order to classify the type of inflammatory infiltrate. In addition, CD68 (M1+, M2+) and CD163 (M1−, M2+) markers were quantified through an immunohistochemistry analysis. The data acquired were submitted to a Mann–Whitney test, with a 5% significance level. Results: The patients had a mean age of 38.6 years and 5.9 years for cysts associated with permanent and primary teeth, respectively. In the histopathological analysis, no significant difference (P = 0.87) was found between radicular cysts in primary and permanent teeth regarding the intensity of the chronic inflammatory infiltrate. A significantly greater prevalence of M2 macrophages (P < 0.05) was observed in the lesions of both permanent and primary teeth, even though both M1 and M2 macrophages were detected. No significant difference (P > 0.05) was found for M1 and M2 macrophages associated with the cysts of primary and permanent teeth. Conclusion: M1 and M2 macrophages were present in radicular cysts associated with primary and permanent teeth, with a greater quantity of M2 cells. The immunophenotypic quantification of M1 and M2 macrophage polarization in radicular cysts associated with primary and permanent teeth were similar. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the specific role of ICAM‐1 in host responses against endodontic infection. Methods: Apical periodontitis was experimentally induced in the mandibular first molars of ICAM‐1 knockout and wild‐type (WT) mice by pulp exposure to the oral environment. At 7, 21 and 42 days following pulp infection, the animals were euthanized and the jaws were prepared for analysis under conventional and fluorescence microscopy (histopathologic and morphometric analysis), immunohistochemistry (polymorphonuclear leucocytes), enzyme histochemistry (osteoclasts and cementoclasts) and RT‐PCR (IL‐1 α, TNF‐α, INF‐γ, IL‐10, RANK, RANKL and OPG). A generalized linear model with GLIMMIX procedure with Satterthwaite approximation method of degrees of freedom, Tukey–Kramer, pseudo‐ranking nonparametric, Bonferroni–Holm multiple testing adjustment, analysis of variance (ANOVA) and the Tukey's multiple comparisons tests were used to evaluate the statistical differences between the groups using SAS 9.4 and the GraphPad Prism 5.0 software (α = 0.05). Results: Compared to WT mice, ICAM‐1 knockout mice had significantly greater bone resorption (P < 0.05), reduced recruitment of neutrophils to periapical inflammatory tissues (P < 0.05) and an increased number of fibroblasts (P < 0.05) at all experimental periods. The osteoclast number was significantly higher in ICAM‐1 KO than that of WT animals at all times (P < 0.05), while there was no significant difference between the groups regarding cementoclasts. At day 21, the level of IL‐1α, RANK, RANKL and IL‐10 had increased significantly in tissues from ICAM‐1 KO versus WT mice (P < 0.05), while no significant difference was observed in TNF‐α and OPG levels (P > 0.05). Tissue levels of INF‐γ were significantly lower in ICAM‐1 KO than those in WT mice (P < 0.05). Conclusion: ICAM‐1 deficiency impaired the host response against endodontic infection, resulting in increased tissue destruction. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the effect of alendronate (ALN) on the development of periapical lesions induced in ovariectomized rats. Methodology: Twenty‐five rats were divided into three groups: sham (control), ovariectomy (OVX) and OVX + ALN. One day after OVX, animals from the OVX + ALN group received the medication via gavage. After 9 weeks, the first molars of all animals were submitted to periapical lesion induction. After 21 days, the animals were euthanized. Femurs were analysed for bone mineral density. The blocks of bone tissue containing the mandibular first molars were submitted to histotechnical processing and staining with haematoxylin and eosin (HE) for periapical lesion analysis under conventional microscopy. At the same time, the morphometric analysis of the periapical lesion area was performed in the fluorescence mode, as well as the histoenzimology for the quantification of osteoclasts and 4′‐6‐diamidino‐2‐phenylindole staining for the quantification of apoptotic osteocytes. In addition, the first maxillary molars were used for analysis of the gene expression of proinflammatory cytokines (IL‐1β, IL‐6 and TNF‐α) and osteoclastogenesis markers (RANKL/OPG). The results were submitted to ANOVA and Kruskal–Wallis tests and Tukey and Dunn post‐tests (significance level of 5%). Results: Ovariectomy reduced bone mineral density of the femur, and treatment with ALN was able to prevent bone loss (P < 0.001). Regarding the microscopic analysis of the periapical region, the sham and OVX + ALN groups had moderately increased periodontal ligament and inflammatory infiltrate, while the OVX group had these parameters increased intensely. The periapical lesions of the OVX group were significantly larger in area in comparison to the other groups (P < 0.001). The OVX group had the largest amount of apoptotic osteocytes, and ALN was able to prevent the apoptosis of these cells, in addition to significantly reducing IL‐6 expression (P < 0.05). OVX and ALN had no effect on RANKL/OPG expression and did not influence the number of osteoclasts around the periapical lesion (P > 0.05). Conclusion: The hypoestrogenic condition induced by OVX aggravated bone resorption, inducing the death of osteocytes and provoking larger periapical lesions. ALN treatment inhibited osteocyte apoptosis and inflammation via IL‐6, inhibiting bone resorption in periapical lesions of ovariectomized rats. [ABSTRACT FROM AUTHOR]

Aim: To investigate the expression of TP63 in apical periodontitis (AP) tissues and the association of single nucleotide polymorphisms (SNPs) in the TP63 gene with AP using a case‐control dataset. Methodology: Expression of TP63 in human AP lesions (apical abscess, radicular cyst, periapical granuloma) was evaluated using immunohistochemistry. A case‐control association study was performed to assess the association of TP63 polymorphisms in individuals having AP with or without associated pain. Cases were defined as subjects with deep caries and AP (n = 151) and subjects with symptomatic apical periodontitis or acute apical abscess (n = 124). Subjects without AP (n = 169) and asymptomatic (n = 196) were used as controls, respectively. Saliva samples were collected as source of genomic DNA. Twelve SNPs in the TP63 gene were selected for genotyping using Taqman chemistry in real‐time PCR. Data analysis was performed using PLINK software. The Bonferroni method was applied to correct for multiple testing; α ≤ 0.004 indicates significant differences between groups. Results: TP63 expression was evident in apical abscesses and radicular cysts, while weaker expression was observed in periapical granulomas. Positive expression was observed in mononuclear cells in the granulation tissues of all AP lesions. Regarding the presence of AP, a trend for allelic association was observed for rs16864812 and rs9810322 (P = 0.04) and rs9810322 genotypes were also nominally associated with AP under a dominant model (P = 0.04). When considering the presence of periapical pain, a trend for allelic and genotypic association was observed for rs10155037 (P = 0.03). Haplotypes were also associated with AP and periapical pain (P ≤ 0.05). Conclusions: Apical periodontitis is a complex multifactorial condition and it is likely that multiple genes and environmental effects may influence its susceptibility, progression or both. TP63 variants may play a role in AP pathogenesis and susceptibility, individually or interactively with other genes. Additional studies in other populations and functional studies are needed to improve understanding of the role of TP63 in AP. [ABSTRACT FROM AUTHOR]

Aim: To investigate the DNA methylation profiles of immune response‐related genes in apical periodontitis (AP) lesions. Methodology: The methylation profiles on the cytosine‐phosphate‐guanine (CpG) regions of 22 gene promoters involved in inflammation and autoimmunity were assessed in 60 human AP lesions and 24 healthy periodontal ligaments (controls) using a pathway‐specific real‐time polymerase chain reaction array (EpiTect® Methyl Signature PCR Array Human Inflammatory Response). Differentially methylated genes were subsequently assessed for their mRNA expression. Data analyses (One‐way anova, Tukey's multiple comparisons tests and Mann–Whitney tests) were performed using GraphPad Prism 6 software. P values ≤ 0.05 were considered statistically significant. Results: Significant DNA hypermethylation was observed for CXCL3 and FADD gene promoters in AP lesions when compared to control tissues (P < 0.001) and among other genes (P < 0.05). In contrast, IL12B and IL4R were associated with significant hypomethylation in comparison to other genes (P < 0.05). IL12B, IL4R, CXCL3 and FADD had differential mRNA expression in AP lesions and controls (P < 0.001). Conclusions: Differential methylation profiles of immune response‐related genes, such as FADD,CXCL3,IL12B and IL4R, may have an influence on individual AP susceptibility and patient treatment outcomes, through their potential contributions to altered expression of disease‐relevant genes. Methylation and/or genetic variations in additional genes may also contribute to the dynamics of AP development and should be considered in future studies. [ABSTRACT FROM AUTHOR]

Aim To evaluate the response of the apical and periapical tissues of dog teeth with apical periodontitis after one-session root canal treatment with and without antimicrobial photodynamic therapy ( aPDT) compared with the use of an intracanal dressing. Methodology Sixty root canals with an induced periapical lesion were instrumented and assigned to three groups: I, two-session root canal treatment using antibacterial dressing with calcium hydroxide-based paste; II, one-session root canal treatment using aPDT; and III, one-session root canal treatment in which the root canals were filled immediately after biomechanical preparation. The animals were euthanized after a 90-day experimental period. The maxillas and mandibles with teeth were submitted to histotechnical processing and haematoxylin-eosin staining. Descriptive microscopic analysis of the apical and periapical region characteristics was performed, as well as morphometric assessment of the periapical lesion areas in fluorescence microscopy. Quantitative data were analysed statistically by the nonparametric Kruskal-Wallis test and Dunn's post-test (α = 0.05). Results Group I was characterized by progressive repair, with the presence of fibres, cells and blood vessels. Group II had periodontal ligaments with the presence of collagen fibres and residual inflammatory cells. Group III had a dense inflammatory infiltrate with extensive oedematous areas and fibrillar dissociation, suggesting a persistent inflammatory and resorptive condition. Regarding periapical lesion size, group I had significantly smaller lesions ( P < 0.05) than groups II and III, which did not differ significantly from each other. Conclusion Two-session root canal treatment using a calcium hydroxide-based dressing was associated with significantly smaller periapical lesions at 90 days and characterized by progressive repair. [ABSTRACT FROM AUTHOR]

Aim To evaluate the transdentinal cytotoxicity of resin-based luting cements ( RBLCs), with no HEMA in their composition, to odontoblast-like cells. Methodology Human dentine discs 0.3 mm thick were adapted to artificial pulp chambers ( APCs) and placed in wells of 24-well plates containing 1 mL of culture medium ( DMEM). Two categories of HEMA-free RBLCs were evaluated: group 1, self-adhesive Rely X Unicem ( RU; 3M ESPE), applied directly to the dentine substrate; and group 2, Rely X ARC ( RARC; 3M ESPE), applied to dentine previously acid-etched and treated with a bonding agent. In group 3 (control), considered as representing 100% cell metabolic activity, no treatment was performed on dentine. The APC/disc sets were incubated for 24 h or 7 days at 37 °C and 5% CO2. Then, the extracts ( DMEM + dental materials components that diffused through dentine) were applied to cultured odontoblast-like MDPC-23 cells for 24 h. After that, the cell viability ( MTT assay), cell morphology ( SEM), total protein production ( TP) and alkaline phosphatase ( ALP) activity were assessed. Data from MTT assay and TP production were analysed by Kruskal-Wallis and Mann-Whitney tests (α = 5%). Data from ALP activity were analysed by one-way anova and Tukey's test (α = 5%). Results In group 1, a slight reduction in cell viability (11.6% and 16.8% for 24-h and 7-day periods, respectively) and ALP activity (13.5% and 17.9% for 24-h and 7-day periods, respectively) was observed, with no significant difference from group 3 (control) ( P > 0.05). In group 2, a significant reduction in cell viability, TP production and ALP activity compared with group 3 (control) occurred ( P < 0.05), regardless of incubation time. Alteration in MDPC-23 cell morphology was observed only in group 2. Conclusions HEMA-free Rely X ARC cement caused greater toxicity to odontoblast-like MDPC-23 cells than did Rely X Unicem cement when both resin-based luting materials were applied to dentine as recommended by the manufacturer. [ABSTRACT FROM AUTHOR]

Aim To evaluate the absence of IL-22 on the progression of periapical lesions in wild-type ( WT) and IL-22 knockout ( IL-22 KO) mice. Methodology The evaluation of the oral microbial profile of mice was performed by Checkerboard DNA- DNA hybridization from saliva samples. Periapical lesions were induced in manbibular first molars by pulpal exposure and evaluated after 7, 21 and 42 days ( n = 15). Haematoxylin-eosin-stained sections were analysed under conventional and fluorescence microscopy to evaluate the tissue features and size of periapical lesions and tartrate-resistant acid phosphatase histoenzymology ( TRAP), Brown & Brenn staining and immunohistochemistry. The scores of the number of bacterial cells present in the oral cavity were analysed by the Mann-Whitney test, and the results and comparisons for periapical lesion size and number of osteoclasts were subjected to one-way anova and Bonferroni's post-test (α = 0.05). Results Significant differences were observed for bacterial load between the groups of animals for 6 bacterial species ( P < 0.05), with five species found in higher levels in the WT group, and one in the IL-22 KO group. WT mice had significantly larger periapical lesions ( P < 0.05) between 7 and 42 days and between 21 and 42 days, with an increase in the mean size and number of osteoclasts. IL-22 KO mice had an increase in periapical lesion size and number of osteoclasts between 7 and 21 days ( P < 0.05). No differences were found between bacteria localization in the root canal system between the experimental groups. Small variations related to the location of immunostaining were found between the groups. Conclusion This study revealed differences in the composition of oral microbiota between mice that may be taken into account in the susceptibility to infections and development of periapical lesions. The absence of IL-22 in mice resulted in smaller periapical lesions with fewer osteoclasts at the final experimental period, suggesting the participation of IL-22 in the host immune and inflammatory response to a periradicular infection. [ABSTRACT FROM AUTHOR]

Aim To quantify bacterial equivalents before and after chemomechanical preparation using 3% sodium hypochlorite ( NaOCl) and intracanal dressing with calcium hydroxide paste ( Ca(OH)2) or 2% Chlorhexidine digluconate gel ( CHX) in necrotic pulps associated or not with apical periodontitis and to further compare this quantification with counts of anaerobic microorganisms. Methodology Prospective clinical trial in 69 single-rooted adult teeth (strict inclusion criteria); CHX group: 34; Ca(OH)2 group: 35. Bacteria samples were taken at baseline ( S1), after chemomechanical preparation ( S2) and after 14 days of intracanal dressing ( S3). Bacterial equivalents were assessed by broad-range real-time polymerase chain reaction (q PCR), and live viable bacteria measured with conventional anaerobic culture ( CFU/mL). Descriptive/inferential analysis was performed with spss vs. 20.0 (α = 0.05) using the Kruskal-Wallis, Mann-Whitney and chi-squared tests and Spearman's correlation coefficients. Results Both groups showed a significant decrease between S1 and S2 (Mann-Whitney U-test; P < 0.001) both in q PCR and in culture. In the Ca(OH)2-group, no variation was observed between S2 and S3 by q PCR and culture. In contrast, the CHX group showed a significant increase from S2 to S3 by both techniques. The two groups were only significantly different in S3 (Mann-Whitney U-test; P ≤ 0.001), with a worse performance in the CHX group. Again, these results were congruent by both approaches. Data from both approaches correlate reasonably ( rS < 0.5). Conclusions Infected root canals contained a high bacterial load, and the chemomechanical root canal preparation reduced bacterial equivalents by 99.1% and anaerobic counts by 98.5%. Intracanal dressings were not efficient at reducing bacterial load, but the 14-day intracanal dressing with Ca(OH)2 performed significantly better than CHX, particularly in cases with apical periodontitis. [ABSTRACT FROM AUTHOR]

The calcium hydroxide ionization of four root canal sealers (Sealapex, CRCS, Sealer 26, and Apexit) was studied by measuring conductivity and pH and by conducting atomic absorption spectrophotometry. Samples 6 mm in diameter and 15 mm long were prepared from these sealers. After setting and 48 h storage in a desiccator, five samples of each material were placed in 50 mL distilled water and analysed after 0,1,2,4, 6 and 24 hand 5, 15 and 30 days. The results showed that Sealapex was the root canal sealer showing the highest pH, ionic calcium and total calcium values (P<0.05) throughout the experimental period, followed by CRCS, Apexit and Sealer 26. [ABSTRACT FROM AUTHOR]