Effect of systemic administration of Bifidobacterium animalis subsp. lactis HN019 on apical periodontitis

Abstract This study aimed to evaluate the effect of Bifidobacterium animalis subsp. lactis (B. lactis) HN019 in drinking water on the development of apical periodontitis (AP) in rats. In total 60 animals were divided into a control group (sound teeth); Group I - regular water without AP; Group II - probiotic water without AP; Group III - regular water with AP; Group IV - probiotic water with AP. AP was induced after 3 days in the control groups and after 7, 21, and 42 days in groups III and IV. The animals were euthanized, and the mandibles were subjected to histotechnical processing. Samples were stained with hematoxylin & eosin (H&E) to identify root canal features, apical and periapical regions. Additionally, histoenzymology was performed to detect osteoclasts, immunohistochemistry was used to identify osteoclastogenesis markers, and the Brown & Brenn technique was applied for microbiological analysis. The data were analyzed using GraphPad Prism 8.0.1 with a significance level of 5%. Although no statistical differences were observed, the groups administered with probiotics showed better conditions in terms of histological aspects seen microscopically. Furthermore, there were no differences in the number of osteoclasts (p > 0.05). The RANKL marker was not found in the probiotic group at 42 days, unlike in group III.

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.

Knowledge, attitudes, and psychosocial impacts among Brazilian Pediatric Dentists during COVID-19 pandemic

Abstract: In this study, we evaluated the knowledge, attitudes, and psychosocial impacts among Brazilian pediatric dentists during the COVID-19 pandemic. A cross-sectional study with primary data collection was carried out using an online structured questionnaire. Data were submitted to descriptive analysis by using absolute and relative frequencies. A chi-square test was used for association analysis and log-linear regression models to estimate the prevalence ratio (5%). The population comprised mostly women and knowledge regarding COVID-19 was satisfactory (above 80% in most items). N95 masks and faceshields were used, albeit 64.22% reported difficulty in providing dental care to children due to the need for extra Personal Protective Equipment. Thirty eight percent provided urgency/emergency dental care, 59.78% performed invasive procedures, 59.56% used high speed handpieces, 8.44% started using cariostatics, and 6.22% introduced the use of chemomechanical caries removal agents. Fear for the future (PR = 1.21) and use of medications (for anxiety, depression, or insomnia) increased (PR = 1.16) among the ones who had wage losses. Brazilian pediatric dentists have knowledge about COVID-19, and attitudes in their clinical routines changed due the pandemic. Financial life was harmed and a negative impact of the pandemic in psychosocial aspects of workers was found.

Comparison of apical periodontitis repair in endodontic treatment with calcium hydroxide-dressing and aPDT

Abstract This study evaluated the effect of antimicrobial photodynamic therapy (aPDT) on the endodontic treatment of apical periodontitis (AP). AP was induced in 48 premolars of 6 dogs. After biomechanical preparation, the teeth were divided into 4 groups: Calcium-Hydroxide (CH)/120d and CH/180d: root canals filled with CH-based dressing for 15 days before obturation; aPDT/120d and aPDT/180d: conditioning with phenothiazine photosensitizer (10 mg/mL) for 1 minute and irradiation with diode laser in the same session as obturation. Root filling was performed with AH Plus sealer. After the experimental periods, animals were euthanized and teeth were submitted for histology. HE staining was performed for descriptive analysis of the periapical region, measurement of apical periodontitis and for inflammatory cells, and blood vessels count. Immunohistochemistry was performed for osteopontin (OPN) and alkaline phosphatase (ALP). Data were analyzed statistically by two-way ANOVA and chi-square test (α = 5%). Teeth in Group CH/120d presented only a slightly enlarged periodontal ligament (PL) with advanced repair. Group aPDT/120d presented the PL moderately enlarged, with moderate inflammatory infiltrate and few collagen fibers. The same pattern was observed at 180 days. AP lesions in CH-treated groups were smaller than those in aPDT-treated groups (p < 0.001) with more blood vessels (p < 0.0001), regardless of the evaluation period, without significant differences in the number of inflammatory cells (p > 0.05). CH-treated groups showed significantly more intense immunostaining for ALP and OPN (p < 0.001) in both periods. Although aPDT stimulated angiogenesis and expression of bone formation markers, the two-session endodontic treatment with CH-based dressing promoted better apical periodontitis repair.

MMP2 and MMP9 are Associated with Apical Periodontitis Progression and Might be Modulated by TLR2 and MyD88

Abstract The aim of this study was to evaluate the expression of MMP2 and MMP9 during apical periodontitis (AP) progression in TLR2 (TLR2 KO) and in MyD88 (MyD88 KO) knockout mice compared to wild type (WT) mice. AP was induced in mandibular first molars of TLR2 KO (n= 18), MyD88 KO (n= 18), and WT mice (n= 18). After 7, 21, and 42 days, the animals were euthanized and the jaws were dissected and subjected to histotechnical processing. Subsequent sections were stained by immunohistochemistry and evaluated for detection of MMP2 and MMP9. Statistical analysis of the semi-quantitative analysis of immunohistochemistry was performed using chi-square test (α = 0.05). In the initial periods of AP progression, an increased expression of MMP9 in the TLR2 KO and MyD88 KO mice was observed. In the final periods of AP progression, a reduction of MMP2 expression and an increase of MMP9 expression in the TLR2 KO mice were observed. MMP2 and MMP9 production was modulated for TLR2 and MyD88 during apical periodontitis progression.

Resumo O objetivo deste estudo foi avaliar a expressão de MMP2 e MMP9 durante a progressão da periodontite apical (AP) em camundongos knockout para TLR2 (TLR2 KO) e MyD88 (MyD88 KO) comparados aos camundongos wild type (WT). A AP foi induzida nos primeiros molares inferiores dos camundongos TLR2 KO (n = 18), MyD88 KO (n = 18) e WT (n = 18). Após 7, 21 e 42 dias, os animais foram eutanaziados e as mandíbulas foram dissecadas e submetidas a processamento histotécnico. As lâminas foram coradas por imuno-histoquímica e analisadas para a detecção de MMP2 e MMP9. A análise estatística semi-quantitativa da imuno-histoquímica foi realizada pelo teste qui-quadrado (α = 0,05). Nos períodos iniciais de progressão AP, foi observada uma expressão aumentada de MMP9 nos camundongos TLR2 KO e MyD88 KO. Nos períodos finais de progressão AP, observou-se uma redução da expressão de MMP2 e um aumento da expressão de MMP9 nos camundongos TLR2 KO. A produção de MMP2 e MMP9 foi modulada por TLR2 e MyD88 durante a progressão da periodontite apical.

Does the CO2 laser reduce bond strength in different types of ceramic brackets?

ABSTRACT OBJECTIVE: The aim of this study was to assess in vitro the influence of the CO2 laser and of the type of ceramic bracket on the shear bond strength (SBS) to enamel. METHODS: A total of 60 enamel test surfaces were obtained from bovine incisors and randomly assigned to two groups, according to the ceramic bracket used: Allure (A); Transcend (T). Each group was divided into 2 subgroups (n = 15): L, laser (10W, 3s); C, no laser, or control. Twenty-four hours after the bonding protocol using Transbond XT, SBS was tested at a crosshead speed of 0.5 mm/min in a universal testing machine. After debonding, the Adhesive Remnant Index (ARI) was evaluated at 10 x magnification and compared among the groups. Data were analyzed by one-way ANOVA, Tukey’s, Mann-Whitney’s and Kruskal-Wallis tests (α = 0.05). RESULTS: Mean SBS in MPa were: AL = 0.88 ± 0.84; AC = 12.22 ± 3.45; TL = 12.10 ± 5.11; TC = 17.71 ± 6.16. ARI analysis showed that 73% of the specimens presented the entire adhesive remaining on the tooth surfaces (score 3). TC group presented significantly higher SBS than the other groups. The lased specimens showed significantly lower bond strength than the non-lased groups for both tested brackets. CONCLUSION: CO2 laser irradiation decreased SBS values of the polycrystalline ceramic brackets, mainly Allure.

RESUMO OBJETIVO: o objetivo deste estudo foi avaliar in vitro a influência do laser de CO2 sobre a resistência ao cisalhamento da colagem (RCC) no esmalte dentário, usando diferentes tipos de braquetes cerâmicos. MÉTODOS: no total, 60 superfícies de esmalte de incisivos bovinos foram obtidas e aleatoriamente divididas em dois grupos, de acordo com o braquete cerâmico utilizado: Allure (A) e Transcend (T). Cada grupo foi dividido em dois subgrupos (n = 15): L, laser (10W, 3s); C, sem laser, ou controle. Vinte e quatro horas após a colagem dos braquetes com o sistema Transbond XT, foi realizado o teste de resistência ao cisalhamento, com velocidade de 0,5 mm/min, em máquina universal de ensaios mecânicos. Após a descolagem, o Índice de Remanescente de Adesivo (IRA) foi avaliado com aumento de 10X e comparado entre os grupos. Os dados foram analisados pelo ANOVA one-way, testes de Tukey’s, Mann-Whitney’s e Kruskal-Wallis (α = 0,05). RESULTADOS: as médias da RCC em MPa foram: AL = 0,88 ± 0,84; AC = 12,22 ± 3,45; TL = 12,10 ± 5,11; TC = 17,71 ± 6,16. A análise do IRA mostrou que 73% dos corpos de prova apresentaram todo o compósito remanescente aderido à superfície do esmalte (escore 3). O grupo TC apresentou valor significativamente maior de RCC do que os outros grupos. Os corpos de prova dos grupos com laser obtiveram valores adesivos significativamente menores do que os corpos de prova dos grupos sem laser, com ambos os tipos de braquetes. CONCLUSÃO: a irradiação com laser de CO2 diminuiu os valores de RCC dos braquetes policristalinos testados, principalmente do Allure.

Evaluation of Chair-Side Assays in High Microbiological Caries-Risk Subjects

The aim of this study was to evaluate the commercial chair-side assays Saliva-Check Mutans and ClinproTM Cario L-PopTM in high microbiological caries-risk dental students compared with conventional semi-quantitative colony counting culture-based technique as the reference method. Saliva samples from 93 subjects of both sexes aged 18-26 years were seeded (Köhler and Bratthall method) on plates containing SB-20M culture medium method and 12 subjects with high caries risk were selected. These 12 individuals were subjected to determination of caries risk using two commercial rapid detection chair-side assays (Saliva-Check Mutans and ClinproTM Cario L-PopTM) according to the manufacturers' instructions. The results were analyzed by the Kappa correlation test using SAS statistical software. There was a perfect agreement (Kappa=1) among the three caries risk evaluation methods - chair-side assays and semi-quantitative CFU count (control) - in all subjects. The results suggest that the commercial chair-side assays evaluated in this study may be practical and useful to identify high microbiological caries-risk subjects.

Resumo O objetivo do estudo foi avaliar os testes comerciais de consultório Saliva-Check Mutans e ClinproTM Cario L-PopTM, em estudantes de Odontologia de alto risco à cárie, comparado à técnica convencional semi-quantitativa baseada em contagem de colônias, como método de referência. Amostras de saliva de 93 estudantes de ambos os sexos, entre 18 e 26 anos de idade, foram semeadas em placas contendo meio de cultura SB-20M e 12 pacientes de alto risco à cárie foram selecionados. Estes 12 indivíduos foram submetidos à determinação de risco à cárie por dois testes comerciais de rápida detecção (Saliva-Check Mutans e ClinproTM Cario L-PopTM), seguindo as instruções dos fabricantes. Os resultados foram analisados pelo teste de correlação Kappa, por meio do software estatístico SAS. Houve uma concordância perfeita (Kappa=1) entre os três métodos de avaliação de risco á cárie - testes comerciais e contagem semi-quantitativa de UFC (controle) - em todos os pacientes. O resultado sugere que os testes comerciais de consultório avaliados neste estudo podem ser práticos e úteis para identificar indivíduos de alto risco microbiológico à cárie.

Microbial contamination and disinfection methods of pacifiers

Objectives To evaluate the microbial contamination of pacifiers by Mutans Streptococci(MS) and the efficacy of different methods for their disinfection.Methods Twenty-eight children were assigned to a 4-stage changeover system with a 1-week interval. In each stage, children received a new pacifier and the parents were instructed to maintain their normal habits for 1 week. After this time, the pacifiers were subjected to the following 4 disinfection methods: spraying with 0.12% chlorhexidine solution, Brushtox® or sterile tap water, and immersion in boiling tap water for 15 minutes. Microbiological culture for MS and Scanning Electron Microscopy (SEM) were performed. The results were analyzed statistically by Friedman’s non-parametric test (a=0.05).Results The 0.12% chlorhexidine spray was statistically similar to the boiling water (p>0.05) and more effective than the Brushtox®spray and control (p<0.05). The analysis of SEM showed the formation of a cariogenic biofilm in all groups with positive culture.Conclusions Pacifiers become contaminated by MS after their use by children and should be disinfected routinely. Spraying with a 0.12% chlorhexidine solution and immersion in boiling water promoted better disinfection of the pacifiers compared with a commercial antiseptic toothbrush cleanser (Brushtox®).

Role of endotoxin in the etiology of periapical lesions: molecular mechanisms involved in endotoxin's recognition and cell activation / Papel da endotoxina na etiologia da lesão periapical: mecanismos moleculares envolvidos no seu reconhecimento e na ativação celular

Periapical lesions are diseases resulting from contamination and necrosis of dental pulp and the progression of this infection toward the periapical tissues. Technological advances in microbiological culture and identification have shown that anaerobic microorganisms, especially Gram-negative, are predominate in root canals of teeth with pulp necrosis and chronic periapical lesions. Gram-negative bacteria not only have different factors of virulence and generate products and sub-products that are toxic to apical and periapical tissues, but also contain endotoxin in the outer membrane of their cell wall. This information is important because endotoxin is released during multiplication or bacterial death, causing a series of biological effects that lead to an inflammatory reaction and resorption of mineralized tissues. Thus, the aim of this work is to carry out a review of the literature on the role of bacterial endotoxin in the etiology of periapical lesions, its mechanism of action, and to elucidate molecular mechanisms involved in endotoxin's recognition by the immune system and cell activation.

As lesões periapicais são patologias resultantes da contaminação e necrose da polpa dental e progressão da infecção em direção aos tecidos periapicais. Os avanços tecnológicos na cultura e identificação microbiana demonstraram que, em canais radiculares de dentes portadores de necrose pulpar e lesão periapical crônica, predominam os microrganismos anaeróbios, particularmente os Gram-negativos. As bactérias Gram-negativas, além de possuírem diferentes fatores de virulência e gerarem produtos e subprodutos tóxicos aos tecidos apicais e periapicais, contêm a endotoxina em sua parede celular. Esse conhecimento é importante, uma vez que a endotoxina é liberada durante a multiplicação ou morte bacteriana, exercendo uma série de efeitos biológicos relevantes, que conduzem a uma reação inflamatória e à reabsorção dos tecidos mineralizados. Sendo assim, o objetivo deste trabalho foi efetuar uma revisão da literatura relativa ao papel da endotoxina bacteriana na etiologia das lesões periapicais, seu mecanismo de ação, bem como elucidar mecanismos moleculares envolvidos no seu reconhecimento pelo sistema imunológico e na ativação celular.

Radiodensitometric and DXA analyses for the measurement of bone mineral density after systemic alendronate therapy

Precise techniques for the measurement of maxillary bone mineral density (BMD) are useful for the early diagnosis of systemic diseases. The aim of this study was to compare in vivo the efficacy of dual-energy x-ray absorptiometry (DXA) and radiographic densitometry for the measurement of BMD after systemic administration of sodium alendronate. Wistar rats were randomly allocated to a control group (n = 5), which received distilled water, and a sodium alendronate group (n = 8), which received two doses of chemically pure sodium alendronate (1 mg/kg) per week. After 8 weeks, the animals were euthanized, the tibias were removed, and the BMD of the proximal tibial metaphysis was analyzed radiographically and by DXA. The data were subjected to statistical analysis by the Kruskal-Wallis test at a significance level of 5%. Both of the techniques revealed that the alendronate-treated group had a significantly higher BMD (p < 0.05) than the control group after 8 weeks of treatment. Comparing the groups with and without alendronate therapy revealed increases of 14.9% and 29.6% in BMD, as detected radiographically and by DXA, respectively. In conclusion, both of the methods were able to detect an increase in BMD of the proximal tibial metaphysis after alendronate therapy.

Utilização de localizadores eletrônicos foraminais na determinação da odontometria, em dentes decíduos / Electronic apex locators to root canal lenght determination, in primary teeth

A determinação do comprimento real de trabalho é uma etapa fundamental para o sucesso clínico, radiográfico e histológico do tratamento endodôntico, principalmente na dentição decídua, com o objetivo de minimizar injúrias periapicais e evitar alterações no germe dos dentes permanentes sucessores. O exame radiográfico é empregado na prática clínica para realização da odontometria, porém a determinação precisa do comprimento do canal radicular é dificultada devido a variações anatômicas, sobreposição de estruturas, distorções, erros técnicos ou erros na projeção. Os localizadores eletrônicos foraminais vêm sendo amplamente utilizados para a realização da odontometria em dentes permanentes, como precisão superior a 90%. Nos últimos anos, esses aparelhos têm sido indicados, também, para dentes decíduos, reduzindo a exposição do paciente infantil à radiação e o tempo de trabalho clínico. O objetivo do presente trabalho será apresentar a indicação, vantagens e eficácia do método eletrônico para odontometria, bem como sua técnica de uso e resultados obtidos na odontometria de dentes decíduos.

Working length determination is an extremely important step of the endodontic treatment. It is particularly critical in primary teeth in order to minimize periapical injury and possible damage to the permanent successor tooth germ. Radiography is traditionally used for root canal length determination. However, an accurate working length determination is dependent on anatomical variations, interference of anatomical structures or errors in projections. Electronic apex locators have been used for working length determination in permanent teeth with up to 90% accuracy. Over the last years, these devices have also been indicated for primary teeth, reducing the exposure of children to x-rays and the clinical chairtime. The purpose of the present study was to discuss the indications, advantages and the efficacy of electronic working length determination. Additionally, this paper describes a clinical sequence and the published results after using these devices in primary teeth.