Experimental Periodontitis Worsens Dopaminergic Neuronal Degeneration.

AIM: To investigate the hypothesis supporting the link between periodontitis and dopaminergic neuron degeneration. MATERIALS AND METHODS: Adult male Wistar rats were used to induce dopaminergic neuronal injury with 6-hydroxydopamine (6-OHDA) neurotoxin and experimental periodontitis via ligature placement. Motor function assessments were conducted before and after periodontitis induction in controls and 6-OHDA-injury-induced rats. Tissue samples from the striatum, jaw and blood were collected for molecular analyses, encompassing immunohistochemistry of tyrosine hydroxylase, microglia and astrocyte, as well as micro-computed tomography, to assess alveolar bone loss and for the analysis of striatal oxidative stress and plasma inflammatory markers. RESULTS: The results indicated motor impairment in 6-OHDA-injury-induced rats exacerbated by periodontitis, worsening dopaminergic striatal degeneration. Periodontitis alone or in combination with 6-OHDA-induced lesion was able to increase striatal microglia, while astrocytes were increased by the combination only. Periodontitis increased striatal reactive oxygen species levels and plasma tumour necrosis factor-alpha levels in rats with 6-OHDA-induced lesions and decreased the anti-inflammatory interleukin-10. CONCLUSIONS: This study provides original insights into the association between periodontitis and a neurodegenerative condition. The increased inflammatory pathway associated with both 6-OHDA-induced dopaminergic neuron lesion and periodontal inflammatory processes corroborates that the periodontitis-induced systemic inflammation may aggravate neuroinflammation in Parkinson's-like disease, potentially hastening disease progression.

Identification and classification of pulp calcifications in posterior teeth according to dental condition using digital panoramic radiography and cone beam CT.

OBJECTIVE: To compare digital panoramic radiography (DPR) and cone beam CT (CBCT) in the detection and classification of pulp calcifications in posterior teeth in relation to tooth condition and its location. METHODS: Two hundred and fifty patients with simultaneous DPR and CBCT scans were selected from a dental image bank. For each posterior tooth, its condition was registered (healthy, restored, or decayed). The presence of calcifications was assessed and classified according to location (coronal or radicular) and type (total obliteration, partial obliteration, narrowing, and no calcification). Chi-square and McNemar tests were used to compare DPR and CBCT results, with a significance level of 5%. DPR diagnostic values were calculated using CBCT as reference. RESULTS: Decayed and restored teeth showed a significantly (P < .001) higher prevalence of pulp calcifications than healthy teeth in both imaging exams. There was a significant discrepancy between the imaging modalities in the identification of calcifications (P < .001), especially for radicular calcifications of maxillary teeth (DPR = 55.2%; CBCT = 30.9%). In the case of coronal calcifications, there was a greater discrepancy between CBCT and DPR in the mandibular teeth (10.7%) than in the maxillary teeth (7.7%). Overall, DPR presents higher sensitivity (0.855) than specificity (0.483) for pulp calcifications detection. CONCLUSION: DPR considerably overestimates pulp calcifications in posterior teeth, as compared to CBCT. A higher prevalence of pulp calcifications is related to decayed and restored teeth.

Investigation of polymorphisms in BMP2, BMP4, SMAD6 and RUNX2 genes and pulp stones.

This study aimed to assess the association between genetic polymorphisms in BMP2 (rs1005464 and rs235768), BMP4 (rs17563), SMAD6 (rs2119261 and rs3934908) and RUNX2 (rs59983488 and rs1200425) and pulp stones (PS). A total of 117 participants, consisting of 63 individuals with PS and 54 without PS, were included. Digital radiographs and a demographic/clinical questionnaire were used. Genomic DNA from salivary cells was genotyped via real-time polymerase chain reaction. Statistical analyses, including Chi-Square, Fisher's exact tests, Poisson regression and dimensionality reduction, were conducted. The rs2119261 polymorphism in the SMAD6 gene showed an association with genotype distribution in the recessive model (p = 0.049). The T-T haplotype in the SMAD6 gene (rs2119261 and rs3934908) was more prevalent in the control group and significantly linked with PS (p = 0.029). No associations were found between PS risk and genetic polymorphisms in BMP2, BMP4 and RUNX2. Polymorphisms in the SMAD6 gene were associated with PS.

Influence of genetic polymorphisms on oral health-related quality of life after root canal treatment

Abstract To evaluate the impact of genetic polymorphisms in interleukins (IL1A rs17561, rs1304037; IL10 rs1800871; IL1RN rs9005), nitric oxide (NOS2 rs2779249, rs2897518) and suppressor of cytokine signaling (SOCS1 rs243327, rs33977706) on oral health-related quality of life (OHRQoL) of patients under-going root canal treatment (RCT). Methods: The sample consisted of 108 participants, presenting single-rooted teeth with asymptomatic periapical periodontitis. The impact of the OHRQoL was recorded using the Oral Health Impact Profile (OHIP-14) before, seven, and 30 days after RCT. Saliva samples were collected as a source of genomic DNA. Genetic polymorphisms were genotyped by Real-Time PCR using the Taqman method. Univariate and Multivariate analyses were used (p<0.05). Results: A significant difference was observed for the polymorphism rs2297518 in the NOS2 gene in functional limitation in the codominant (p=0.037) and recessive (p=0.001) models; in the physical pain (p<0.001 in both models); in psychological discomfort (p<0.001 in both models); in physical disability (p<0.001 in both models) and in psychological disability (p<0.001 in both models). Polymorphisms in the SOCS1 gene, in the recessive model, rs33977706 (p=0.045) and rs243327 (p=0.019), influenced the OHRQoL in the psychological discomfort domain. Conclusions: Polymorphisms in NOS2 and SOCS1 genes influenced the OHRQoL of patients undergoing RCT.

Resumo Avaliar o impacto de polimorfismos genéticos em interleucinas (IL1A rs17561, rs1304037; IL10 rs1800871; IL1RN rs9005), óxido nítrico (NOS2 rs2779249, rs2897518) e supressor da sinalização de citocinas (SOCS1 rs243327, rs33977706) na qualidade de vida relacionada à saúde bucal (QVRSB) de pacientes submetidos a tratamento endodôntico (TE). Métodos: A amostra foi composta por 108 participantes, que apresentavam dentes unirradiculares com lesão periapical assintomática. O impacto da QVRSB foi registrado usando o Oral Health Impact Profile (OHIP-14) antes, sete e 30 dias após o TE. Amostras de saliva foram coletadas como fonte de DNA genômico. Os polimorfismos genéticos foram genotipados por PCR em tempo real usando o método Taqman. Análises univariadas e multivariadas foram utilizadas (p<0,05). Resultados: Observou-se diferença significativa para o polimorfismo rs2297518 no gene NOS2 na limitação funcional nos modelos codominante (p=0,037) e recessivo (p=0,001); na dor física (p<0,001 em ambos os modelos); no desconforto psicológico (p<0,001 em ambos os modelos); na deficiência física (p<0,001 em ambos os modelos) e na deficiência psicológica (p<0,001 em ambos os modelos). Polimorfismos no gene SOCS1, no modelo recessivo, rs33977706 (p=0,045) e rs243327 (p=0,019), influenciaram a QVRSB no domínio desconforto psicológico. Conclusões: Polimorfismos nos genes NOS2 e SOCS1 influenciaram a QVRSB de pacientes submetidos a TE.

Evaluation of 2- and 3-dimensional anatomic parameters of C-shaped root canals with cone beam computed tomography, microcomputed tomography, and nanocomputed tomography.

OBJECTIVE: The objective of this study was to evaluate 2-dimensional (2D) and 3D morphometric parameters of C-shaped root canals on cone beam computed tomography (CBCT) and microcomputed tomography (microCT) images using nanocomputed tomography (nanoCT) as the reference standard. STUDY DESIGN: Sixty mandibular molars with C-shaped canals were individually scanned using nanoCT and microCT. Cone beam computed tomography acquisitions were then performed with 4 CBCT systems, using high and standard resolutions. The 2D parameters of roundness and major and minor diameters were obtained in the cross sections of the root canals at 1, 2, and 3 mm from the root apex. The 3D parameters of surface area, volume, and structure model index were measured considering the entire extension of the root canals. Absolute error (AE) in measurement was calculated against the nanoCT values. Data were statistically analyzed with the Shapiro-Wilk test and analysis of variance (α = 0.05). RESULTS: No significant differences in AE were discovered for the 2D parameters among microCT and the CBCT scans. The AE values for the 3D parameters of volume and surface area were significantly smaller in microCT compared to all CBCT units (P < .05). Significantly lower AE values for surface area were observed in high resolution compared to standard resolution for all CBCT units (P < .05). Structure model index did not differ significantly among microCT and all CBCT protocols. CONCLUSIONS: Cone beam computed tomography images showed accuracy for evaluating 2D parameters and over- and underestimation for 3D parameters.

TNF-α-TNFR1 Signaling Mediates Inflammation and Bone Resorption in Apical Periodontitis.

INTRODUCTION: The aim of this study was to investigate the role of the proinflammatory axis TNF-α-TNFR1 in experimentally induced periapical inflammation and bone resorption in mice. METHODS: After receiving Ethics Committee Approval (2019.1.139.58.0), experimental apical periodontitis was induced by means of inoculating oral microorganisms into the root canals of molars of mice. Genetically deficient tumor necrosis factor-α receptor-1 mice (TNFR1-/-; n = 50) response was compared with that of C57Bl6 wild-type mice (wild-type; n = 50) after 7, 14, 28, and 42 days. The analyses performed were micro-computed tomographic, histopathologic, histomicrobiological, and histometric evaluation, tartrate-resistant acid phosphatase staining, immunohistochemistry, and quantitative reverse transcriptase polymerase chain reaction. Data were analyzed by using one-way analysis of variance, followed by Tukey or Bonferroni tests (α = 5%). RESULTS: TNFR1-/- mice exhibited lower recruitment of neutrophils at 14, 28, and 42 days (P < .05), which resulted in reduced area and volume of apical periodontitis at 42 days (P < .05). The number of osteoclasts was also lower in TNFR1-/- animals at 14 and 42 days (P < .01), along with reduced synthesis of CTSK, MMP-9, and COX-2. Expression of RANKL, but not OPG, was reduced at 14 and 42 days (P < .001). The highest RANKL expression over OPG (ratio > 1) was found in wild-type animals at 7 (P < .0001) and 42 days (P < .001). CONCLUSIONS: Periapical inflammation and bone resorption were exacerbated in wild-type animals compared with TNFR1-/- mice, demonstrating that the TNF-α-TNFR1 signaling pathway mediated catabolic events in bone after root canal contamination.

Mechanism of action of Bioactive Endodontic Materials

Abstract A continuous search for bioactive materials capable of supporting the replacement of damaged pulp tissue, with effective sealing potential and biocompatibility, has represented the attention of studies over the last decades. This study involves a narrative review of the literature developed by searching representative research in PUBMED/MEDLINE and searches in textbooks associated with the mechanism of action of bioactive materials (calcium hydroxide, mineral trioxide aggregate (MTA), and calcium silicate cements). The reflective analysis of the particularities of the chemical elements of these materials, considering the tissue and antibacterial mechanism of action, allows a better understanding of the characteristics and similarities in their tissue responses. Calcium hydroxide paste remains the antibacterial substance of choice as intracanal dressing for the treatment of root canal system infections. Calcium silicate cements, including MTA, show a favorable biological response with the stimulation of mineralized tissue deposition in sealed areas when in contact with connective tissue. This is due to the similarity between the chemical elements, especially ionic dissociation, the potential stimulation of enzymes in tissues, and the contribution towards an alkaline environment due to the pH of these materials. The behavior of bioactive materials, especially MTA and the new calcium silicate cements in the biological sealing activity, has been shown to be effective. Contemporary endodontics has access to bioactive materials with similar properties, which can stimulate a biological seal in lateral and furcation root perforations, root-end fillings and root fillings, pulp capping, pulpotomy, apexification, and regenerative endodontic procedures, in addition to other clinical conditions.

Resumo Uma busca contínua de materiais bioativos com capacidade de substituir o tecido pulpar danificado, com efetiva capacidade de selamento e biocompatibilidade, tem representado a atenção e foco de muitos estudos ao longo das últimas décadas. Este estudo envolve uma revisão narrativa da literatura desenvolvida por meio de pesquisas representativas encontradas no PUBMED/MEDLINE e pesquisas em livros didáticos associadas ao mecanismo de ação de materiais bioativos (hidróxido de cálcio, agregado de trióxido mineral (MTA) e cimentos de silicato de cálcio). A presente análise reflexiva das particularidades dos elementos químicos destes materiais bioativos, considerando o mecanismo de ação tecidual e antibacteriano, possibilita um melhor entendimento das características e similaridades no comportamento tecidual. A pasta de hidróxido de cálcio continua sendo a substância antibacteriana de escolha como medicação intracanal para o tratamento das infecções do sistema de canais radiculares. Este fato se deve a disponibilidade química de íons cálcio e hidroxila do hidróxido de cálcio aos tecidos, e a inibição enzimática bacteriana. Os cimentos de silicato de cálcio, dentre os quais inclui o MTA, apresentam uma resposta biológica favorável ao estímulo à deposição de tecido mineralizado nas áreas seladas e em contato com tecido conjuntivo. Este fato é decorrente da similaridade entre os elementos químicos, em especial devido a dissociação iônica, ao potencial estímulo de enzimas teciduais, e a contribuição com um meio alcalino decorrente do pH destes materiais. O comportamento dos materiais bioativos, em especial o MTA e os novos cimentos de silicato de cálcio na atividade de selamento biológico mostraram efetivos. A endodontia contemporânea atualmente conta com o potencial de materiais bioativos com propriedades análogas capaz de estimular o selamento biológico em perfurações radiculares laterais e de furca, em obturações radiculares, capeamento pulpar, pulpotomia, apicificação e procedimentos endodônticos regenerativos, além de outras condições clínicas.

Genetic polymorphism in the tumour necrosis factor alpha gene (G-308A) is associated with persistent apical periodontitis in Brazilians.

AIM: To investigate if there was an association between genetic polymorphisms in tumour necrosis factor (TNF)-⍺ and its receptors TNFRSF1A and TNFRSF1B with persistent apical periodontitis (PAP) in Brazilian subjects. METHODOLOGY: Patients who had pulpal necrosis and apical periodontitis at the time of treatment, with at least 1-year of follow-up after non-surgical root canal treatment were recalled. Three hundred and seventy eight subjects were included, 150 subjects with signs/symptoms of PAP and 228 subjects with root canal-treated teeth exhibiting healthy perirradicular tissues (healed). Genomic DNA was extracted from saliva and used for TNF-⍺ (rs1800629), TNFRSF1A (rs1800693) and TNFRSF1B (rs1061622) genotyping by real-time PCR. Genotypes and alleles frequencies were evaluated by c2 or Fisher's exact tests and odds ratios were implemented (α = 5%). RESULTS: The genetic polymorphism in TNF-α (rs1800629) was associated as a protective factor for the development of PAP (p < .05), once subjects who presented at least one allele A (AA+AG X GG), had a higher chance to lesion repair (p < .05). The polymorphisms rs1800693 and rs1061622 in TNF receptors (TNFRSF1A and TNFRSF1B, respectively) were not associated with the development of PAP (p > .05). CONCLUSIONS: The observed results demonstrate that polymorphism in TNF-α but not in its receptors is associated with PAP.

Influence of bioceramic intracanal medication on the bond strength of bioceramic root canal sealer

Abstract To investigate the influence of the remaining volume of a new intracanal medication based on bioceramic compounds on the bond strength (BS) and formation of an adhesive interface between calcium silicate-based and epoxy resin-based root canal sealers. For this purpose, the specimens were distributed according to the intracanal medication (n = 26): Bio-C Temp (BCT) and Ultracal XS (UXS). The roots were scanned in microCT, and after 7 days, the medication was removed. Then a new scan was performed to evaluate the volume of medication remaining. Subsequently, 40 specimens were redistributed into 2 subgroups (n = 10) and filled according to the sealer used: AH Plus (AHP) and Bio-C Sealer (BCS), to assess the bond strength by using the push-out test, and the adhesive interface by confocal laser fluorescence microscopy (CLSM) and scanning electron microscopy (SEM). The t test showed a smaller remainder of BCT (1.77 ± 0.86) compared with UXS (10.47 ± 5.78), irrespective of the root third evaluated. The BS showed that teeth with BCT + BCS had higher bond strength values (3.70 ± 1.22) when compared to the other groups: BCT + AHP (2.15 ± 1.07), UXS + BCS (3.18 ± 1.09) and UXS + AHP (2.11 ± 1.02) (p<0.001). The cervical third had higher BS when compared with the middle and apical thirds (p < 0.001), and higher number of adhesive failures. The adhesive interface in SEM and CLSM images showed better adaptation for the association between BCT + BCS. Intracanal medication and silicate-based endodontic sealer appeared to interact chemically by forming a biomineralizing layer, allowing for an increase in the bond strength and forming an adhesive interface between the materials, with no or less gap formation.

Impact of access cavities on root canal preparation, restorative protocol quality, and fracture resistance of teeth

Abstract The survival of endodontically treated teeth depends on the remaining tooth structure. The aim of this study was to evaluate the impact of different access cavities on root canal preparation, restorative protocol, and fracture resistance of endodontically treated teeth. Fifty-six mandibular molars were divided into control (n=8) and experimental (n=16) groups according to access cavity: Traditional, Conservative, and Truss; and redistributed (n=8) according to instrumentation protocols: Reciproc Blue and R-motion. After, teeth were scanned in micro-CT and then filled and redistributed according to composite resin restoration (n=8): Filtek One BulkFill and Filtek Z350. A new micro-CT scan was performed to analyze the restorative material. Then, samples were submitted to fracture resistance testing and the failure pattern was determined. Data were analyzed using paired T-test, ANOVA, Tukey, and chi-square tests (α=0.05). In Truss, R-Motion promoted less transportation in different thirds of root canals. Higher percentages of voids (5.05%) and filling material (11.7%) were observed in Truss. Fracture resistance values were higher for the control group, followed by Truss, Conservative, and Traditional. The predominant failure pattern was type-II. In Truss, reciprocating instruments with smaller taper showed less canal transportation. Also, Truss provided higher values of fracture resistance, although it presented a higher percentage of voids and remaining filling material. Thus, in Truss, reciprocating files with smaller taper showed less canal transportation, and these cavities provided higher values of fracture resistance, although it presented a higher percentage of voids and remaining filling material.

Method to determine the root canal spatial geometry using an algorithm of the e-Vol DX CBCT software

Abstract This study evaluated a method to determine the spatial geometry of root canal preparation (RCP) using navigation dynamics and a specific algorithm from a new CBCT software (e-Vol DX). CBCT scans of 168 root canals of mandibular molars were acquired before and after RCP, using nickel-titanium (NiTi) instruments (ProTaper Next, BioRace, Reciproc Blue, and WaveOne Gold). The spatial geometry of the root canals and the operative risk of disproportional wear of dentinal walls after RCP were evaluated using a new CBCT software. A 3-point scoring system was used after the measuring of cementum/dentin thickness before and after RCP in all root thirds. The root thirds were distributed into three parts of similar sizes, and the scores were categorized at three levels: 1. mild risk (1/3), 2. moderate risk (2/3), 3. severe risk (3/3). These levels were proposed according to the risk of creating disproportionate shapes, thin walls, or perforations. The data were analyzed statistically by Fischer's exact test (α = 5%). There were no significant differences in operative risk among the NiTi engine-driven systems, for the distal or mesial walls of all the root canal thirds (p>0.05). The spatial geometry method to assess operative risk allows clinical planning for a predictable enlargement of the root canal in all root thirds. Based on using a map-reading strategy on root canals in CBCT scans, NiTi engine-driven instruments did not present an increased operative risk during RCPs.

Resumo Este estudo avaliou um método para determinar a geometria espacial do preparo do canal radicular (PCR) usando uma dinâmica de navegação e um algoritmo específico do software e-Vol DX. Imagens de tomografia computadorizada de feixe cônico (TCFC) de 168 molares inferiores foram adquiridas antes e depois do PCR, usando instrumentos de níquel-titânio (NiTi) (ProTaper Next, BioRace, Reciproc Blue e WaveOne Gold). A geometria espacial dos canais radiculares e o risco operatório de desgaste desproporcional das paredes dentinárias após o preparo foram avaliados usando o software de TCFC e-Vol DX. Um sistema de Score de 3 pontos foi usado após a mensuração da espessura cemento/dentina antes e depois do PCR, em toda extensão dos canais radiculares. Os terços radiculares foram distribuídos em três partes de tamanhos semelhantes, e os Scores foram categorizados em três níveis: 1. risco leve (1/3), 2. risco moderado (2/3), 3. risco severo (3/3). Esses níveis foram propostos de acordo com o risco de criar formas desproporcionais, paredes finas ou perfurações radiculares. Os dados foram analisados estatisticamente pelo teste exato de Fischer ((=5%). Não houve diferenças significativas no risco operatório entre os sistemas de NiTi acionados a motor, para as paredes distal ou mesial em todos os terços do canal radicular (p>0,05). O método de geometria espacial para avaliar o risco operatório permite o planejamento clínico para um alargamento previsível do canal radicular em todos os terços radiculares. Com base no uso de uma estratégia de navegação dinâmica de canais radiculares de molares inferiores analisados em imagens de TCFC, os instrumentos de NiTi acionados estudados não apresentaram um aumento do risco operatório durante o preparo dos canais radiculares.

Analysis of the mandibular molars root canals morphology. Study by computed tomography

Abstract This study aimed to analyze the root and root canal morphology of mandibular first and second molars using CBCT images. A total of 2,400 mandibular molars exams were selected from 600 patients aged between 18 and 75 years. The number of roots, number of root canals, and root canal configuration according to the Vertucci classification were verified. Overall, 94.92% of mandibular first molars and 90.17% of mandibular second molars had two separate roots. Among the biradicular molars, the first molars showed a greater incidence of type IV canals in the mesial root and type I in the distal root. In the second molars, the most common canal form was type IV in the mesial root and type I in the distal root. In the triradicular molars, the type IV and type I configurations were the most common in the mesial root of the first molar and second molar, respectively. In both triradicular molars, there was a prevalence of type I canal in the distal and DL roots. Statistical analysis was performed at a significance level of 0.05. The number of roots was correlated with gender (Spearman test), and the canal's configuration with gender and bilaterality (Wilcoxon test). The subpopulation studied has a high incidence of bilateral symmetry and mandibular molars with two roots with two distinct mesial canals and one distal canal. The bilateral configuration is possible to estimate the number of canals, especially in images that are difficult to visualize, such as atresic canals.

Absence of Tumor Necrosis Factor Receptor 1 Inhibits Osteoclast Activity in Apical Dental Resorption Caused by Endodontic Infection in Mice.

INTRODUCTION: The aim of this study was to evaluate osteoclastogenesis and dental resorption resulting from endodontic infection in wild-type (WT) and tumor necrosis factor receptor 1 genetically deficient (TNFR1 KO) mice. METHODS: After approval by the ethics committee on the use of animals, 40 mice were distributed into 2 experimental groups based on time periods: 14 days (n = 10 WT mice and n = 10 TNFR1 KO mice) and 42 days (n = 10 WT mice and n = 10 TNFR1 KO mice). After these periods, morphometric analysis was performed using bright field and fluorescence microscopy and tartrate-resistant acid phosphatase histoenzymology to identify osteoclasts. One-way analysis of variance followed by the Tukey post hoc test was used for the statistical analysis (α = 0.05). RESULTS: WT mice in the 42-day period had a greater apical dental resorption in the distal root of the first molar than TNFR1 KO mice (P < .05). On the other hand, TNFR1 KO mice showed a smaller number of osteoclasts on the dental surface than WT mice (P < .05). CONCLUSIONS: WT mice with apical periodontitis had more extensive apical dental resorptions and a larger number of osteoclasts on the tooth surface than TNFR1 KO mice.

Genetic, Cellular and Molecular Aspects involved in Apical Periodontitis

Abstract The development, establishment and repair of apical periodontitis (AP) is dependent of several factors, which include host susceptibility, microbial infection, immune response, quality of root canal treatment and organism's ability to repair. The understanding of genetic contributions to the risk of developing AP and presenting persistent AP has been extensively explored in modern Endodontics. Thus, this article aims to provide a review of the literature regarding the biochemical mediators involved in immune response signaling, osteoclastogenesis and bone neoformation, as the genetic components involved in the development and repair of AP. A narrative review of the literature was performed through a PUBMED/MEDLINE search and a hand search of the major AP textbooks. The knowledge regarding the cells, receptors and molecules involved in the host's immune-inflammatory response during the progression of AP added to the knowledge of bone biology allows the identification of factors inherent to the host that can interfere both in the progression and in the repair of these lesions. The main outcomes of studies evaluated in the review that investigated the correlation between genetic polymorphisms and AP in the last five years, demonstrate that genetic factors of the individual are involved in the success of root canal treatment. The discussion of this review gives subsides that may help to glimpse the development of new therapies based on the identification of therapeutic targets and the development of materials and techniques aimed at acting at the molecular level for clinical, radiographic and histological success of root canal treatment.

Resumo O desenvolvimento, estabelecimento e reparo da periodontite apical (PA) depende de vários fatores, que incluem a susceptibilidade do hospedeiro, infecção microbiana, resposta imune, bem como a qualidade do tratamento do canal radicular e a capacidade de reparo do organismo. A compreensão das contribuições genéticas para o risco de desenvolver a PA e apresentar PA persistente tem sido extensivamente explorada na Endodontia moderna. Assim, este manuscrito pretende fornecer uma revisão da literatura em relação aos mediadores bioquímicos envolvidos na sinalização da resposta imune, osteoclastogênese e neoformação óssea, bem como os componentes genéticos envolvidos no desenvolvimento e reparo da PA. Uma revisão narrativa da literatura foi realizada através de uma pesquisa nas bases PUBMED/MEDLINE e uma pesquisa manual nos principais livros sobre a PA. O conhecimento sobre as células, receptores e moléculas envolvidas na resposta imuno-inflamatória do hospedeiro durante a progressão da PA somado ao conhecimento da biologia óssea, especialmente o papel dos osteoblastos, osteócitos e osteoclastos no turnover ósseo, permite a identificação de fatores inerentes ao hospedeiro que podem interferir tanto na progressão como no reparo destas lesões. Os principais resultados dos estudos avaliados na revisão que investigaram a correlação entre polimorfismos genéticos e PA, nos últimos cinco anos, demonstram que os fatores genéticos do indivíduo estão envolvidos no sucesso do tratamento do canal radicular. A discussão desta revisão fornece subsídios que podem ajudar a vislumbrar o desenvolvimento de novas terapias baseadas na identificação de alvos terapêuticos e no desenvolvimento de materiais e técnicas destinadas a atuar a nível molecular para o sucesso clínico, radiográfico e histológico do tratamento endodôntico.

Management of periapical lesion with persistent exsudate.

This case describes the treatment and follow-up of a mandibular molar in an 18-year-old female with a periapical cyst. Thus, it becomes important to know which options should we take when faced with a clinical situation that we cannot resolve through conventional methods, and which techniques and approaches we have to achieve treatment success. This case showed the treatment plan and follow-up, by the use of CBCT images, from a previously treated mandibular molar with a large periapical abscess and cystic lesion, in which, the first treatment plan approach was to make the endodontic retreatment. During the chemo-mechanical preparation the presence of permanent intracanal purulent exudate made it impossible to dry the canals, impeding obturation of the root canal system. Due to this clinical situation, a surgical approach was performed with the intention of reduce this permanent exudate and to execute a decompression technique. Clinical findings, periapical radiographs and cone beam computed tomographic, indicated almost complete resolution of the radiolucency, after a one-year follow-up.

Este relato de caso descreve o tratamento e acompanhamento de um molar inferior em uma jovem de 18 anos com cisto periapical. Assim, torna-se importante saber quais opções devemos tomar diante de uma situação clínica que não podemos resolver pelos métodos convencionais, e quais técnicas e abordagens temos para alcançar o sucesso do tratamento. Este caso mostrou o plano de tratamento e acompanhamento, por meio de imagens de tomografia computadorizada de feixe cônico (TCFC), de um molar inferior previamente tratado com grande abscesso periapical e lesão cística, no qual, a primeira abordagem do plano de tratamento foi fazer o retratamento endodôntico. Durante o preparo químico-mecânico a presença de exsudato purulento intracanal permanente impossibilitou a secagem dos canais, impedindo a obturação do sistema de canais radiculares. Devido a essa situação clínica, foi realizada abordagem cirúrgica com a intenção de reduzir esse exsudato permanente e executar uma técnica de descompressão. Após um ano de acompanhamento, os achados clínicos e radiográficos indicaram processo de reparo.

Management of periapical lesion with persistent exsudate

Resumo Este relato de caso descreve o tratamento e acompanhamento de um molar inferior em uma jovem de 18 anos com cisto periapical. Assim, torna-se importante saber quais opções devemos tomar diante de uma situação clínica que não podemos resolver pelos métodos convencionais, e quais técnicas e abordagens temos para alcançar o sucesso do tratamento. Este caso mostrou o plano de tratamento e acompanhamento, por meio de imagens de tomografia computadorizada de feixe cônico (TCFC), de um molar inferior previamente tratado com grande abscesso periapical e lesão cística, no qual, a primeira abordagem do plano de tratamento foi fazer o retratamento endodôntico. Durante o preparo químico-mecânico a presença de exsudato purulento intracanal permanente impossibilitou a secagem dos canais, impedindo a obturação do sistema de canais radiculares. Devido a essa situação clínica, foi realizada abordagem cirúrgica com a intenção de reduzir esse exsudato permanente e executar uma técnica de descompressão. Após um ano de acompanhamento, os achados clínicos e radiográficos indicaram processo de reparo.

Abstract This case describes the treatment and follow-up of a mandibular molar in an 18-year-old female with a periapical cyst. Thus, it becomes important to know which options should we take when faced with a clinical situation that we cannot resolve through conventional methods, and which techniques and approaches we have to achieve treatment success. This case showed the treatment plan and follow-up, by the use of CBCT images, from a previously treated mandibular molar with a large periapical abscess and cystic lesion, in which, the first treatment plan approach was to make the endodontic retreatment. During the chemo-mechanical preparation the presence of permanent intracanal purulent exudate made it impossible to dry the canals, impeding obturation of the root canal system. Due to this clinical situation, a surgical approach was performed with the intention of reduce this permanent exudate and to execute a decompression technique. Clinical findings, periapical radiographs and cone beam computed tomographic, indicated almost complete resolution of the radiolucency, after a one-year follow-up.

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.

Impact of several NiTi-thermally treated instrumentation systems on biomechanical preparation of curved root canals in extracted mandibular molars.

AIM: To evaluate the shaping ability of several heat-treated nickel-titanium systems used to prepare root canals with moderate and severe curvature, in extracted mandibular molars, by micro-computed tomography, considering their variation in kinematics and design. METHODOLOGY: Curved-mesial roots of mandibular molars were randomly selected and assigned into 4 balanced experimental groups (n = 10), established by determining homogeneous 3D parameters of volume and surface area: R-Motion (RM) size 30, 0.04 taper (RM; FKG Dentaire), Reciproc Blue (RCB) size 25, 0.08 taper (RCB; VDW GmbH), HyFlex CM (HFX) size 30, 0.04 taper (HFX; Coltène Whaledent) and XP-endo Shaper size (XPS) 30, 0.01 taper (XPS; FKG Dentaire). The volume of irrigation was established at 10 ml of 2.5% NaOCl. Throughout the entire root canal preparation procedures, the samples were fixed in a vice submerged in a container with water monitored at 37°C. Dimensional cross-sectional measures of area, perimeter, roundness, major/minor diameters and 3-dimensional (volume, surface area, structure model index - SMI) parameters as well as the smallest dentine thickness along the cervical and middle root thirds were evaluated by micro-CT. Data were analysed using analysis of variance and post hoc Tukey tests (α = 5%). RESULTS: Reciproc Blue and XPS had significantly greater mean increases in cross-sectional area measurements, only in the middle third, when compared with RM and HFX (p < .05). RM, RCB and XPS had a similar increase in measurements of length and width of perimeter (p > .05), and HFX had significantly lower mean increases in perimeter values only when compared with XPS (p < .05). RCB and XPS had significantly greater mean increases in volume when compared with RM and HFX (p < .05). RM had a significantly lower difference in SMI after preparation, compared with RCB, HFX and XPS (p < .05). The smallest dentine thickness was observed after the use of RCB (p < .05), in the danger and safety zones. CONCLUSIONS: XP-endo Shaper and RM had a shaping ability similar to that of instruments with larger tapers, achieved with less dentine removal in danger and safe zones in curved-mesial canals of extracted molar teeth treated on a laboratory benchtop.

Impact of COVID-19 on gender gap in dental publications: a retrospective cohort with three Brazilian journals

Abstract This was a retrospective cohort study to investigate the impact of COVID-19 pandemic on the gender gap in articles submitted to three international dental journals based in Brazil. All submissions performed to Brazilian Dental Journal, Brazilian Oral Research, and Journal of Applied Oral Science before (2019) and during the pandemic (2020) were assessed. Gender of the first, last, and corresponding authors were collected. Other variables collected were journal, continent studied by authors and stage of their careers (classified according to authors' highest degree), and final decision reached in the article. Absolute and relative frequencies with 95% confidence intervals, Pearson's Chi-square tests, and Fisher's Exact test were used (α = 0.05). In total, 4,726 unique submissions were analyzed. A higher proportion of early-career authors was observed during the pandemic (44.8% to 49.3%, p = 0.021). Most articles were rejected but without association with gender. Increased proportion of male first authors from before to during the pandemic was observed (39% to 42.1%, p = 0.034). Drop in the proportion of articles with women as first authors was observed for researchers in their early- (65.9% to 58.8%, p = 0.02) and mid-career stages (63% to 55.8%, p = 0.014). Reduction in women as first authors was observed during the pandemic in South and Central Americas (66.7% to 61.5%, p = 0.010), and when the last author was a female, or the corresponding author was a male. In conclusion, a disproportionate impact on female dental researchers in submitting articles in the period from before to during the pandemic was observed when considering first authorship, suggesting that the COVID-19 may have increased the gender inequality in dental science.

Heat-treated NiTi instruments and final irrigation protocols for biomechanical preparation of flattened canals

Abstract This study evaluate shaping ability of heat-treated NiTi-alloy instruments associated with different final irrigation protocols in flattened root canals. Thirty human mandibular incisors with flattened root canals were divided into 5 groups (n = 10): (XP) Original Protocol XP-endo Shaper; (XP-WT) Original Protocol XP-endo Shaper with working time variation; (XP-K) XP-endo Shaper with kinematics variation; (XP-WTK) XP-endo Shaper with kinematics and working time variations; (Hyflex) Hyflex CM. For the variation in working time protocols the same sample of the XP-endo Shaper groups with and without kinematic variation were used. To evaluate final irrigation protocols, groups 1, 3 and 5 were submitted to 3 protocols: (NI) No irrigation (n = 2); (CI) conventional irrigation (n = 4), and (EndoVac) irrigation (n = 4). The samples were scanned by microcomputed tomography and prepared for scanning electron microscopy evaluation. Quantitative data were evaluated using the parametric ANOVA test, with statistical significance level set at 5%, and qualitative data obtained were compared to establish the agreement between examiners through the Kappa test. It was observed that in the analysis of XP-endo Shaper protocols, the additional working time did not cause difference in any of parameters evaluated (p > 0.05) in relation to time recommended by manufacturer. Compared to Hyflex, XP-K showed highest mean volume increase (p < 0.05) and lowest percentage of untouched walls (p < 0.05). In the qualitative evaluation, final irrigation protocol with EndoVac provided the best cleaning results when associated with XP-K and with Hyflex. Thus, supplementary techniques are effective tools to enhance cleaning and to promote higher touch of walls during root canal preparation.