The effects of NLRP3 inflammasome inhibition or knockout in experimental apical periodontitis induced in mice.

OBJECTIVE: To evaluate the effects of NLRP3 inflammasome inhibition or knockout in experimental apical periodontitis (AP) induced in mice. METHODS: The experimental AP was induced by pulpal exposure. To evaluate NLRP3-specific inhibitor medication (MCC950), WT mice received intraperitoneal injections, while the control received PBS (n = 10). In addition, to evaluate NLRP3 knockout, 35 wild-type (WT) and 35 NLRP3-/- mice were divided into a control group (without pulpal exposure, n = 5) and three experimental groups: after 2, 14 and 42 days after pulpal exposure (n = 10). Microscopic and molecular analyzes were carried out using a significance level of 5%. RESULTS: Exposure to MCC950 did not affect the periapical lesion size after 14 days (P = 0.584). However, exposed mice had a lower expression of IL-1ß, IL-18 and caspase-1 (P = 0.010, 0.016 and 0.002, respectively). Moreover, NLRP3-/- mice showed a smaller periapical lesion after 14 and 42 days (P = 0.023 and 0.031, respectively), as well as a lower expression of IL-1ß after 42 days (P < 0.001), of IL-18 and caspase-1 after 14 (P < 0.001 and 0.035, respectively) and 42 days (P = 0.002 and 0.002, respectively). NLRP3-/- mice also showed a lower mRNA for Il-1ß, Il-18 and Casp1 after 2 (P = 0.002, 0.036 and 0.001, respectively) and 14 days (P = 0.002, 0.002 and 0.001, respectively). CONCLUSIONS: NLRP3 inflammasome inhibition or knockout can attenuate the inflammatory events that result in the periapical lesion (AP) formation after pulpal exposure in mice. CLINICAL RELEVANCE: The NLRP3 inflammasome may be a therapeutic target for AP, and new approaches may verify the impact of its inhibition (through intracanal medications or filling materials) on the bone repair process and treatment success.

Interferon-gamma inducible protein 16 and type I interferon receptors expression in experimental apical periodontitis induced in wild-type mice.

AIM: The aim of this study was to evaluate the IFI16 and IFN-α/ß receptors expression during the genesis and development of experimental apical periodontitis (AP) in mice teeth. METHODOLOGY: Apical periodontitis was induced in the lower first molars of 40 C57BL/6 mice. They were divided according to the experimental periods 2, 7, 14, 21 and 42 days (n = 8 per group). Five animals were used as a control group (without AP). Specimens were submitted to histological processing for description of the inflammatory process, immunostaining for the presence/absence and localization of IFI16 and IFN-α/ß receptors (qualitative and semi-quantitative analysis) and tartrate-resistant acid phosphatase (TRAP) histoenzimology. RESULTS: The results showed a gradual development of AP over the experimental times. The expression of IFI16 was noticeably more exacerbated in the experimental early period (day 2) whilst the lowest expression was observed in the control group (p = .02). For IFN-α/ß receptors, a higher intensity staining was observed 42 days after AP induction, that was statistically different from the control group (p = .02). In addition, the number of TRAP-positive cells was higher on the later periods (days 21 and 42; p < .001). CONCLUSION: IFI16 protein expression was highest during the early periods after AP induction in mice teeth, whilst IFN-α/ß receptor expression was highest after AP became established.

Effect of root surface treatment with denusomab after delayed tooth replantation.

OBJECTIVES: To evaluate denosumab, a human monoclonal antibody that mimics the effects of osteoprotegerin in bone metabolism, as a topical treatment of root surface to be used prior to delayed tooth replantation. MATERIALS AND METHODS: Thirty-six rats' right incisors were used. Teeth were extracted and divided into: delayed replantation without root surface treatment (control); delayed replantation with root surface treatment with denosumab 60 mg/mL and 30 mg/mL, respectively, for 10 min both experimentals groups. After that, the root canals were filled with calcium hydroxide and replanted. After 15 and 60 days, the animals were euthanized, and the samples were collected and processed for microscopic analysis. Histological sections were performed, and stained with HE to describe the dental characteristics, measure ankylosis, replacement resorption, and dental resorption by conventional microscopy. Also, was performed Brown & Brenn staining and immunohistochemistry for RANKL, OPG, and periostin. RESULTS: Denosumab 60 mg/mL reducted ankylosis (p < 0.0001), replacement resorption (p < 0.0001), and tooth resorption, 60 days after replantation, compared to untreated replanted teeth (p < 0.005). Lower bacterial contamination in root surface in the denosumab treatment groups was found, regardless of the concentration used (p < 0.001). Also, denosumab treatment inhibited the expression of RANKL without modulating OPG. Periostin was observed in periodontal ligament of replanted tooth, although this labelling was absent in the ankylosis areas, in both experimental periods. CONCLUSION: Treatment of the root surface with denosumab at 60 mg/mL of rat teeth before delayed replantation reduced dental root resorption compared with the untreated teeth after 60 days. CLINICAL RELEVANCE: Survival of a replanted tooth has been a challenge in clinical practice. The use of a medication, such as denosumab, to limit dental root resorption represents an important therapeutical approach.

Periodontal ligament repair after active splinting of replanted dogs' teeth.

BACKGROUND/AIM: The high rate of root resorption resulting from tooth replantation represents a serious clinical problem. In order to prevent ankylosis and replacement resorption, the contemporary literature highlights the importance of using a flexible stabilization for traumatized teeth. For this purpose, orthodontic devices may be promising for obtaining a better prognosis and periodontal repair. The aim of this study was to evaluate the effect of an active splinting protocol with controlled force in dog's teeth following replantation. MATERIAL AND METHODS: Sixty premolar roots from three dogs were used. They were submitted to endodontic treatment, hemisected, atraumatically extracted and subsequently replanted. They were divided into four groups: Passive Stabilization (n = 20)-after 20 min in a dry medium; Active Stabilization (n = 20)-after 20 min in a dry medium; Negative control (n = 10)-immediate replantation and passive Stabilization; and Positive control (n = 10)-90 min of extra-alveolar time and passive Stabilization. The samples were collected and submitted to histologic processing. They were then evaluated for the count of inflammatory cells, expression of neurotrophin 4, osteoclasts, apoptotic cells and collagen fibres. The results were submitted to ANOVA or Kruskal-Wallis statistical tests followed by Tukey or Dunn post-tests (α = 5%). RESULTS: Passive Stabilization with orthodontic brackets without traction used after replantation had the highest number of inflammatory cells (p = .0122), osteoclasts (p = .0013) and percentage of collagen fibres in the periodontal ligament (p < .0001) when compared to Active Stabilization with orthodontic brackets applying amild tensile force. Neurotrophin 4 had no statistically significant difference (p = .05), regardless of the treatment. The apoptotic cells count revealed statistical differences (p < .0001) between Active Stabilization (189.70 ± 47.99) and Positive Control (198.90 ± 88.92) when compared to Passive Stabilization (21.19 ± 32.94). CONCLUSION: The active splinting protocol using orthodontic appliances generating a light and controlled force favoured periodontal ligament repair of replanted teeth.

Minimally interventive restorative care of teeth with molar incisor hypomineralization and open apex-A 24-month longitudinal study.

AIM: To assess the efficacy of treatment using a minimally invasive approach (selective removal of carious tissue, restoration and preventive strategies) in immature permanent molars with MIH. DESIGN: A total of 281 patients, aged 6-8 years, with carious lesions (ICDAS 5-6), severe MIH, and incomplete root formation (one tooth/patient) were included. After clinical and radiographic examinations, selective carious tissue removal was performed, and the teeth received interim restoration for 6 months and were then restored with composite resin. Clinical and radiographic follow-up was undertaken, 6, 12, 18, and 24 months. A protocol of preventive oral care measures was established and repeated at each follow-up, including diet counselling, oral hygiene instruction, dental plaque control, and topical application of fluoride varnish containing CPP-ACP. All clinical procedures and evaluations were done by a single operator. RESULTS: Clinical and radiographic success was observed 24 months after treatment in 96.8% of the cases. Failures were due to enamel fracture at restoration margins, resulting in pulpitis and absence of apex closure. CONCLUSION: Selective removal of carious tissue, interim, and subsequently definitive restoration, combined with home and professional preventive measures, maintained marginal integrity of restorations in immature permanent molars with severe MIH, confirmed by pulp vitality and occurrence of apexogenesis.

Inflammatory response to bioceramic and epoxy resin-based endodontic sealers implanted in mice subcutaneous tissue: An in vivo study.

To evaluate the inflammatory tissue response to BioRoot™ RCS (BR) and AH Plus Jet (AHPJ) sealers implanted in mice subcutaneous tissue. It was hypothesized that the inflammatory tissue response to BR would be milder than to AHPJ. An in vivo study was carried out using isogenic mice. The sealers were implanted during standardized surgical procedures. The inflammatory response was evaluated by microscopic analysis and von Kossa reaction in the reactionary tissue around the specimens after 7, 21, and 63 days. For comparisons, a zinc oxide and eugenol sealer (ZOE) was used as a positive control, in addition to a negative control without a sealer (n = 10 per group/period). All statistical analyses considered a significance level of 5%. All endodontic sealers triggered an inflammatory tissue response after 7 days. BR had a higher inflammatory cell count and a thicker fibrous capsule when compared with AHPJ, but both were less inflammatory than ZOE (p < .001). After 21 days, BR continued to trigger an intense inflammatory tissue response, higher in both microscopic parameters compared to AHPJ, and a thicker fibrous capsule than ZOE (p < .001). After 63 days, the inflammatory tissue response decreased in BR, matching the fibrous capsule thickness with AHPJ and ZOE. BR promoted intense calcium precipitation in all study periods. After 63 days, AHPJ and BR sealers were more biocompatible to subcutaneous mice tissue, but AHPJ present better early inflammatory response, as well as BR showed potential bioactivity. RESEARCH HIGHLIGHTS: The inflammatory tissue response triggered by a bioceramic endodontic sealer (BR) was not milder than that triggered by an epoxy-resin based endodontic sealer (AHPJ) during the first 3 weeks, considering the microscopic analysis of the reactionary tissue.

Bifidobacterium animalis subsp. lactis HN019 has antimicrobial activity against endodontic pathogens in vitro.

The aim of the present study was to evaluate, in vitro, the antimicrobial activity of the probiotic Bifidobacterium animalis subsp. lactis HN019, through the well technique, against 10 microorganisms can be found involved in endodontic infections. The antimicrobial activity of the probiotic was performed on Streptococcus mutans, Streptococcus sobrinus, Lacticaseibacillus casei, Enterococcus faecalis, Staphylococcus aureus, Candida albicans, Porphyromonas gingivalis, Porphyromonas endodontalis, Fusobacterium nucleatum and Prevotella intermedia. For the control group, it was used non-pathogenic bacteria Escherichia coli, Saccharomyces cerevisiae, and Kocuria rizhopilla. After 48 to 72 h of incubation of the petri dishes containing the culture medium, the microorganism strains, and the probiotic, the plates were examined to assess the uniformity of microbial growth, presence of contaminants, and the halo of inhibition. After visual inspection, the reading of the halo of inhibition was performed with the aid of a digital caliper using a reflected light source to illuminate the inverted plate on a black, opaque background after removing the cap. Thus, 3 values were obtained from each bacterial inoculum, which were added and divided by three to obtain the average of the values. The results of the in vitro study demonstrated that the probiotic B. animalis subsp. lactis HN019 promoted the inhibition of all strains of the pathogens evaluated, with the exception of Candida albicans, demonstrating antimicrobial activity on these microorganisms.

Online teaching, quality of life and anxiety of Brazilian dental professors during the COVID-19 outbreak.

The COVID-19 pandemic led to changes in academic teaching and dental education, but the impact on dental professors' mental health and quality of life remains poorly understood. Thus, the objective of this study was to evaluate the impacts of social distancing and online teaching related to COVID-19 on the quality of life and anxiety of Brazilian dental professors. This was a cross-sectional study conducted from August 2020 to October 2020. Three instruments were used in an online version: a questionnaire about personal data, academic information and online teaching activities, the Generalized Anxiety Disorders 7 (GAD7) scale, and the Abbreviated World Health Organization Quality of Life (WHOQOL-bref) scale. All instruments were sent by e-mail, social media, and messaging apps to private and public universities and professors. Of the 318 responses, 187 (58.8%) were from female professors. Moreover, lack of good internet access and adequate place for online teaching, difficulties in producing teaching materials, and housework roles had a significant impact on the quality of life and anxiety scores (all p-values < 0.05). Also, Brazilian dental professors who declared that they would make greater efforts if the activities were face-to-face had significantly worse quality of life and anxiety scores, and female professors had significantly higher anxiety scores (all p-values < 0.05). These results provide evidence of a negative effect of social distancing and online teaching activities related to COVID-19 outbreak on the health-related quality of life and mental health of Brazilian dental professors.

Subcutaneous tissue reaction and gene expression of inflammatory markers after Biodentine and MTA implantation.

The aim of this study was to evaluate the subcutaneous connective tissue response of isogenic mice exposed to tricalcium silicate (Biodentine) and aggregated mineral trioxide (ProRoot MTA). A total of 120 mice were divided into 4 groups in 3 different experimental periods (7, 21 and 63 days): Biodentine; Pro-Root MTA; zinc oxide-eugenol and; Negative control - Sham. After the experimental periods microscopic descriptive, semi-quantitative and quantitative analysis of the inflammatory process were analyzed on H&E sections and evaluation of the gene expression of Il10, Infg, Il6, Il1r1 and Tnf (qRT-PCR) were performed. The data obtained were analyzed using the chi-square test and two-way analysis of variance (ANOVA) followed by the Bonferroni post-test (5% significance level). Results: In the microscopic analysis, a slight inflammatory infiltrate was observed, with a predominance of sparse macrophages and polymorphonuclear cells, slight tissue fibrosis, regular fibrous capsule and with dystrophic calcifications, in all groups that received the materials (Biodentine and Pro-Root MTA). In parallel, all materials modulated the gene expression of the different cytokines and receptors evaluated. Conclusion: Pro-Root MTA and Biodentine showed a tissue compatibility, mediated inflammation, with increased fibrous tissue and production of pro- and anti-inflammatory cytokines.

Interferon activated gene 204 protects against bone loss in experimental periodontitis.

BACKGROUND: Periodontal destruction can be the result of different known and yet-to-be-discovered biological pathways. Recent human genetic association studies have implicated interferon-gamma inducible protein 16 (IFI16) and absent in melanoma 2 (AIM2) with high periodontal interleukin (IL)-1ß levels and more destructive disease, but mechanistic evidence is lacking. Here, we sought to experimentally validate these observational associations and better understand IFI16 and AIM2's roles in periodontitis. METHODS: Periodontitis was induced in Ifi204-/- (IFI16 murine homolog) and Aim2-/- mice using the ligature model. Chimeric mice were created to identify the main source cells of Ifi204 in the periodontium. IFI16-silenced human endothelial cells were treated with periodontal pathogens in vitro. Periodontal tissues from Ifi204-/- mice were evaluated for alveolar bone (micro-CT), cell inflammatory infiltration (MPO+ staining), Il1b (qRT-PCR), and osteoclast numbers (cathepsin K+ staining). RESULTS: Ifi204-deficient mice> exhibited >20% higher alveolar bone loss than wild-type (WT) (P < 0.05), while no significant difference was found in Aim2-/- mice. Ifi204's effect on bone loss was primarily mediated by a nonbone marrow source and was independent of Aim2. Ifi204-deficient mice had greater neutrophil/macrophage trafficking into gingival tissues regardless of periodontitis development compared to WT. In human endothelial cells, IFI16 decreased the chemokine response to periodontal pathogens. In murine periodontitis, Ifi204 depletion elevated gingival Il1b and increased osteoclast numbers at diseased sites (P < 0.05). CONCLUSIONS: These findings support IFI16's role as a novel regulator of inflammatory cell trafficking to the periodontium that protects against bone loss and offers potential targets for the development of new periodontal disease biomarkers and therapeutics.

M1 and M2 macrophages phenotypes modulation after stimuli with materials used in endodontic treatment.

The aim of this study was to evaluate the M1 and M2 macrophage modulation after stimuli with different materials used during endodontic treatment. In bone marrow-derived macrophage cell culture, from males C57BL/6 wild-type (WT) mice, gene expression analysis of markers to M1 and M2 macrophages was performed by qRT-PCR (Cxcl10, CxCL9, iNOS, Arg1, Chil3, Retnla and MRC1) and cytokine quantification by Luminex® (GM-CSF, IL-10, IL-6, IL-1ß and TNF-α) after exposure to the five endodontic sealers: AH Plus, Sealapex Xpress, Endosequence BC Sealer, BioRoot RCS and a calcium hydroxide-based paste. For normal values, ANOVA test was used, followed by Tukey post-test. For non-normal values, the Kruskall-Wallis test was used. BioRootTM RCS and EndoSequence BC SealerTM stimulated the highest expression of markers for M1 macrophages, while calcium hydroxide-based paste stimulated the lowest expression of these gene markers. For M2 protein markers, BioRootTM RCS presented the highest stimulation while calcium hydroxide-based paste also presented the lowest stimulation. It was concluded that all the evaluated filling materials increased the genetic expression of pro- and anti-inflammatory markers: TNF-α and IL-10 respectively. The others proinflammatory mediators showed differences against the filling materials. However, this process did not induce the inflammatory response polarization, resulting in a hybrid macrophage.

Negative Pressure Irrigation Presents Mineralizing Potential in Dogs' Immature Teeth with Periapical Lesion.

The objective of this in vivo study was to assess the effect of the root canal irrigation by negative and positive apical pressure on the expression of molecules that are an indicative of cell differentiation with mineralizing phenotype in teeth of dogs with incomplete rhizogenesis and induced periapical lesion. A total of 30 teeth (60 roots) were distributed into 3 groups (n=20): EndoVac®, Conventional and Control. After 90 days, the routine histotechnical procedures were performed and the sections were submitted to immunohistochemical technique for the staining of osteopontin (OPN), alkaline phosphatase (ALP) and the RUNX2 transcription factor in the apical and periapical regions of the roots. A semi-quantitative analysis of the positive immunostaining was performed and the intensity of the expression was classified in absent (0), mild (1), moderate (2), or intense (3). Scores data were statistically analyzed by the Kruskal-Wallis non-parametric test and Dunn post-test, and the significance level was set at 5%. RUNX2 immunostaining revealed that in the negative pressure group there was a significantly stronger (p<0.05) immunostaining in comparison to the control group. Regarding the OPN expression, it was not possible to detect a statistically significant difference between the groups (p>0.05). After analyzing ALP immunostaining, a statistically significant difference was observed between the groups (p<0.05), and the negative pressure group showed a markedly stronger mark immunostaining than the control group. The results of the present in vivo study allowed concluding that negative apical pressure irrigation presents mineralizing potential in immature teeth with apical periodontitis.

Tissue Response after Subcutaneous Implantation of Different Glass Ionomer-Based Cements.

The aim of this study was to evaluate the subcutaneous connective tissue response of isogenic mice after implantation of different glass ionomer-based cements (EQUIA® Forte Fil, EQUIA® Fil and Ketac™ Universal Aplicap™). Eighty-seven isogenic BALB/c mice were allocated in 12 groups, 9 were considered as experimental groups (Ketac, E. Fil and E. Forte at 7, 21 and 63 days) and 3 controls (empty polyethylene tubes at 7, 21 and 63 days). After the experimental periods, the subcutaneous connective tissue surrounding the implanted material was removed and subjected to histotechnical processing and staining with hematoxylin and eosin. A histopathological description of the tissue reaction surrounding each material and a semi-quantitative analysis of collagen fiber formation and inflammatory infiltrate were performed. Additionally, the thickness of the granulomatous tissue in contact with each material was measured. Data were analyzed statistically (α=0.05) by the Kruskal-Wallis test, followed by Dunn post-test. Initially, the collagen fiber formation was not different among all the tested materials (p>0.05) but was different at 21 days with the control group presenting the most advanced stage of collagen fiber formation. At 63 days, EQUIA® Forte Fil group showed the most advanced stage of collagen fiber formation, compared to EQUIA® Fil group (p<0.05). The inflammatory infiltrate was not different among the tested materials in any experimental period (p>0.05). The thickness of the granulomatous tissue was greater in the E. Forte group, compared to control in all periods. All glass ionomer-based cements showed tissue compatibility, according to the evaluated parameters.

Evaluation of genetic polymorphisms in MMP2, MMP9 and MMP20 in Brazilian children with dental fluorosis.

Recent studies suggested that genetics contribute to differences in dental fluorosis (DF) susceptibility among individuals having the same environmental exposure. This study evaluated if MMP2, MMP9 and MMP20 are expressed during enamel development and assessed the association between polymorphisms in these genes with DF. Mice susceptible and resistant to DF were used to evaluate if MMPs were candidate genes for DF. The animals received fluoride and their enamels were used for immunohistochemistry. Additionally, 481 subjects from a city with fluoridation of public water supplies were recruited. Genotyping was performed using real time PCR. Allele/genotype frequencies were compared between groups. MMP2, MMP9 and MMP20 immunostaining was detected in both animal groups. DF was observed in 22.4% of the subjects. A borderline association was observed in MMP2 (rs243865), MMP9 (rs17576) and in MMP20 (rs1784418) (p = 0.06, p = 0.08 and p = 0.06 respectively). Briefly, MMPs were expressed during enamel maturation and genetic polymorphisms were not associated with DF.

Novel endodontic sealers induced satisfactory tissue response in mice.

OBJECTIVES: The aim of this study was to evaluate the subcutaneous response induced by Roeko Guttaflow2 (RG), Sealapex Xpress (SX), AH Plus (AHP) sealers. METHODS: 100 BALB/c mice received implants in the subcutaneous tissue with the tested materials (10 animals per period for each evaluated sealer) and were evaluated after different experimental periods (7, 21 and 63 days), in each animal was placed a tube, the control group was an empty tube. Histological analysis evaluated semi-quantitatively the inflammatory infiltration, collagen fiber formation and tissue thickness. In addition, immunohistochemistry was performed for interleukin-6 (IL-6). Data were statistically analyzed (α = 0.05). RESULTS: RG promoted a greater collagen fiber formation at 7 days and 63 days compared to the CG (p = 0.004) and AHP (p = 0.005) respectively, while at 21 days, the SX promoted a greater reaction (p = 0.021). For the tissue thickness, there was a greater reaction at 7 days with CG (p = 0.0156) and with RG at 63 days (p = 0.03). Regarding the inflammatory infiltrate, there was no difference at 7 days and 63 days (p = 0.5; p = 0.27), while at 21 days, a statistically difference was found between SX, CG (p = 0.04) and RG (p = 0.027). In addition, the presence of IL-6 was observed in almost all groups, with a more intense marking at 7days. SIGNIFICANCE: All cements evaluated presented a satisfactory tissue response, however, RG was the one that presented a more satisfactory tissue response.

Immunohistochemical and mRNA expression of RANK, RANKL, OPG, TLR2 and MyD88 during apical periodontitis progression in mice.

OBJECTIVE: To evaluate and correlate, in the same research, the mRNA expression and the staining of RANK, RANKL, OPG, TLR2 and MyD88 by immunohistochemistry in the apical periodontitis (AP) progression in mice. MATERIAL AND METHODS: AP was induced in the lower first molars of thirty-five C57BL/6 mice. They were assigned to four groups according to their euthanasia periods (G0, G7, G21 and G42). The jaws were removed and subjected to histotechnical processing, immunohistochemistry and real-time reverse transcription-PCR (qRT-PCR). Data were analyzed with parametric and nonparametric tests (α=0.05). RESULTS: An increase of positive immunoreactivity for RANK, RANKL, OPG, TLR2 and MyD88 was observed over time (p<0.05). The RANKL expression was different between the groups G0 and G42, G21 and G42 (p=0.006), with G42 presenting the higher expression in both comparations. The OPG expression was statistically different between the groups G0 and G7, G7 and G21 and G7 and G42 (p<0.001), with G7 presenting higher expression in all the time points. The TLR2 expression was different between the groups G0 and G42 (p=0.03), with G42 showing the higher expression. The MyD88 expression presented a statistical significant difference between groups G7, G21 and G42 compared with G0 (p=0.01), with G0 presenting the smallest expression in all the comparisons. The Tnfrsf11/Tnfrsf11b (RANKL/OPG) ratio increased with the AP progression (p=0.002). A moderate positive correlation between MyD88 and RANKL (r=0.42; p=0.03) and between MyD88 and TLR2 (r=0.48; p<0.0001) was observed. CONCLUSION: The expression of the RANK, RANKL, OPG, MyD88 and TLR2 proteins as well as the ratio Tnfrsf11/Tnfrsf11b (RANKL/OPG) increased with AP progression. There was also a moderate positive correlation between the expression Myd88-Tnfrsf11 and Tlr2-Myd88, suggesting the relevance of Tlr2-Myd88 in bone loss due to bacterial infection.

Apical Negative Pressure irrigation presents tissue compatibility in immature teeth.

AIM: To compare the apical negative pressure irrigation (ANP) with conventional irrigation in the teeth of immature dogs with apical periodontitis. METHODS: Fifty-two immature pre-molar root canals were randomly assigned into 4 groups: ANP (n=15); conventional irrigation (n=17); healthy teeth (control) (n = 10); and teeth with untreated apical periodontitis (control) (n=10). After induction of apical periodontitis, teeth were instrumented using EndoVac® (apical negative pressure irrigation) or conventional irrigation. The animals were euthanized after 90 days. The sections were stained by HE and analyzed under conventional and fluorescence microscopy. TRAP histoenzymology was also performed. Statistical analyses were performed with the significance level set at 5%. RESULTS: There was difference in the histopathological parameters between ANP and conventional groups (p<0.05). The ANP group showed a predominance of low magnitude inflammatory infiltrate, a smaller periodontal ligament, and lower mineralized tissue resorption. There were no differences in the periapical lesion extensions between the ANP and conventional groups (p>0.05). However, a lower number of osteoclasts was observed in the ANP group (p<0.05). CONCLUSION: The EndoVac® irrigation system presented better biological results and more advanced repair process in immature teeth with apical periodontitis than the conventional irrigation system, confirming the hypothesis.

Online teaching, quality of life and anxiety of Brazilian dental professors during the COVID-19 outbreak

Abstract: The COVID-19 pandemic led to changes in academic teaching and dental education, but the impact on dental professors' mental health and quality of life remains poorly understood. Thus, the objective of this study was to evaluate the impacts of social distancing and online teaching related to COVID-19 on the quality of life and anxiety of Brazilian dental professors. This was a cross-sectional study conducted from August 2020 to October 2020. Three instruments were used in an online version: a questionnaire about personal data, academic information and online teaching activities, the Generalized Anxiety Disorders 7 (GAD7) scale, and the Abbreviated World Health Organization Quality of Life (WHOQOL-bref) scale. All instruments were sent by e-mail, social media, and messaging apps to private and public universities and professors. Of the 318 responses, 187 (58.8%) were from female professors. Moreover, lack of good internet access and adequate place for online teaching, difficulties in producing teaching materials, and housework roles had a significant impact on the quality of life and anxiety scores (all p-values < 0.05). Also, Brazilian dental professors who declared that they would make greater efforts if the activities were face-to-face had significantly worse quality of life and anxiety scores, and female professors had significantly higher anxiety scores (all p-values < 0.05). These results provide evidence of a negative effect of social distancing and online teaching activities related to COVID-19 outbreak on the health-related quality of life and mental health of Brazilian dental professors.

Subcutaneous tissue reaction and gene expression of inflammatory markers after Biodentine and MTA implantation

Abstract The aim of this study was to evaluate the subcutaneous connective tissue response of isogenic mice exposed to tricalcium silicate (Biodentine) and aggregated mineral trioxide (ProRoot MTA). A total of 120 mice were divided into 4 groups in 3 different experimental periods (7, 21 and 63 days): Biodentine; Pro-Root MTA; zinc oxide-eugenol and; Negative control - Sham. After the experimental periods microscopic descriptive, semi-quantitative and quantitative analysis of the inflammatory process were analyzed on H&E sections and evaluation of the gene expression of Il10, Infg, Il6, Il1r1 and Tnf (qRT-PCR) were performed. The data obtained were analyzed using the chi-square test and two-way analysis of variance (ANOVA) followed by the Bonferroni post-test (5% significance level). Results: In the microscopic analysis, a slight inflammatory infiltrate was observed, with a predominance of sparse macrophages and polymorphonuclear cells, slight tissue fibrosis, regular fibrous capsule and with dystrophic calcifications, in all groups that received the materials (Biodentine and Pro-Root MTA). In parallel, all materials modulated the gene expression of the different cytokines and receptors evaluated. Conclusion: Pro-Root MTA and Biodentine showed a tissue compatibility, mediated inflammation, with increased fibrous tissue and production of pro- and anti-inflammatory cytokines.

Resumo Objetivo: Avaliar a resposta do tecido conjuntivo subcutâneo de camundongos isogênicos expostos à Biodentine™ e ao Trióxido Mineral Agregado (MTA). Métodos: Um total de 120 camundongos foram divididos em 4 grupos e 3 períodos experimentais diferentes (7, 21 e 63 dias): Biodentine™ (Septodont, Saint Maur des Fosses, França); Pro-Root MTA (Dentsplay, Tulsa, EUA); óxido de zinco eugenol (Biodinâmica Química e Farmacêutica LTDA., Ibiporã, PR - Brasil); e controle negativo - Sham. Após os períodos experimentais, análises microscópicas descritivas, semiquantitativas e quantitativas do processo inflamatório foram analisadas nos cortes de H&E e ainda, foi realizada a avaliação da expressão gênica de Il10, Infg, Il6, Il1r1 e Tnf (qRT-PCR). Os dados obtidos foram analisados por meio do teste do qui-quadrado e da análise de variância (ANOVA) two-way, seguido do pós-teste de Bonferroni (nível de significância de 5%). Resultados: Na análise microscópica observou-se discreto infiltrado inflamatório, com predomínio de macrófagos esparsos e polimorfonucleares, leve fibrose tecidual, cápsula fibrosa regular e com calcificações distróficas, em todos os grupos que receberam os materiais (Biodentine ™ e Pro-Root MTA). Paralelamente, todos os materiais modulam a expressão gênica das diferentes citocinas e receptores avaliados. Conclusão: Pro-Root MTA e Biodentine™ mostraram compatibilidade tecidual, inflamação mediada, com aumento do tecido fibroso e produção de citocinas pró- e antiinflamatórias.

Physicochemical Properties of Root Canal Filling Materials for Primary Teeth.

This study evaluated physiochemical proprieties of a calcium hydroxide-based paste (Calen®) combined with a zinc oxide cement at different ratios (1:0.5, 1:0.65, 1:0.8 and 1:1). Materials were compared regarding setting time, pH variation, radiopacity, solubility, dimensional changes, flow and release of chemical elements. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Longer setting time and higher dimensional changes and solubility values were exhibited by 1:0.65 and 1:0.5 ratios (p<0.05). The 1:0.5 and 1:0.65 ratios exhibited the highest pH values at all time points. All materials exhibited high radiopacity values. Significant differences were found only between 1:0.5 and 1:1 ratios for calcium and zinc release (p<0.05), whereas the amount of zirconium was similar among all groups (p>0.05). Considering the evaluated proprieties, combinations of Calen® paste with ZO at 1:0.5 and 1:0.65 ratios had the best results as root canal filling materials for use in primary teeth.