Study of anatomical variations in premolars by cone beam computerized tomography in a radiologic clinic in Piauí / Estudo de variações anatômicas em pré-molares por tomografia computadoriza de cone beam em uma clínica radiológica no Piauí

Introduction: Root canal cleaning is the main objective of endodontic treatment and requires knowledge of the internal anatomy. The premolars are evidenced in the literature with great anatomical variations. In view of this, studies indicate that the use of Cone Beam Computed Tomography helps in the visualization of highly complex anatomy. Objective: to describe the anatomical variations in maxillary and mandibular premolars using cone beam computed tomography in a radiologic clinic in Piaui. Methods: 54 cone beam computed tomography scans with 160 premolars were used, produced using the Orthopantomograph OP300 equipment and analyzed by multiplanar reconstructions: axial, coronal and sagittal. Data regarding sex, number of roots and canals were recorded to compare and classify according to Vertucci. Results: the maxillary first pre-molars had 63.5% two roots,83.7% with one root and the mandibular pre-molars mostly with one root. Regarding the number of channels, 92.3% of the first premolars had two channels, most of them maxillary second premolars and mandibular premolars only one channel. Vertucci variations of types I, II, III and IV were verified in single-rooted elements, observing a great variation in superior elements. As for the prevalence of sex, only the first superiors showed greater variation in males. Conclusions: the upper first premolars prevailed with a great anatomical variation in relation to the other premolars with prevalence of Vertucci Type I and in males.

Introdução: a limpeza do canal radicular é o principal objetivo do tratamento endodôntico e requer conhecimento da anatomia interna. Os pré-molares são evidenciados na literatura com grandes variações anatômicas. Diante disso, estudos indicam que o uso da Tomografia Computadorizada Cone Beam auxilia na visualização de anatomias de alta complexidade. Metodologia: foram utilizadas 54 tomografias computadorizadas de feixe cônico com 160 pré-molares, produzidas no equipamento Orthopantomograph OP300 e analisadas por reconstruções multiplanares: axial, coronal e sagital. Os dados referentes ao sexo, número de raízes e canais foram registrados para comparação e classificação segundo Vertucci. Resultados: os primeiros pré-molares superiores apresentavam 63,5% de duas raízes, 83,7% dos segundos pré-molares superiores tinham uma raiz e a maioria dos pré-molares inferiores tinha uma raiz. Em relação ao número de canais, 92,3% dos primeiros pré-molares possuíam dois canais, sendo a maioria segundos pré-molares superiores e pré-molares inferiores apenas um canal. Vertucci variações dos tipos I, II, III e IV foram verificadas nos elementos uniradiculares, observando-se a grande variação nos elementos superiores. Quanto à prevalência do sexo, apenas os primeiros superiores apresentaram maior variação no sexo masculino. Conclusão: os primeiros pré-molares superiores prevaleceram com grande variação anatômica em relação aos demais pré-molares com prevalência de Vertucci Tipo I e no sexo masculino.

Dietary supplementation with multi-strain formula of probiotics modulates inflammatory and immunological markers in apical periodontitis

Abstract Objective The aim of this study was to evaluate whether probiotics multi-strain formula affects the development of apical periodontitis (AP) induced in rats. Methodology 16 Wistar rats were divided in two groups (n=8): rats with AP fed with regular diet (Control-C (CG)); rats with AP, fed with regular diet and supplemented with multi-strain formula (one billion colony-forming units (CFU)): GNC Probiotic Complex (PCG) ( Lactobacillus acidophilus, Lactobacillus salivaris, Lactobacillus plantarum, Lactobacillus rhamnosus, Bifidobacterium bifidum, Bifidobacterium animalis subs. lactis and Streptococcus thermofilus ). AP was induced in the upper and lower first molars by dental pulp exposure to the oral environment. PCG was administered orally through gavage for 30 days during the AP development. After this period the animals were euthanized and the mandibles were removed and processed for histologic analysis, and immunochemical assays for interleukin (IL)-6, IL-10, IL-1β, RANKL, OPG, and TRAP. The Mann-Whitney U test and Student's t test were performed (P<.05). Results The CG showed more intense inflammatory infiltrate than the PCG group (P<.05). IL-1β, IL 6 and RANKL decreased in the PCG group compared with CG (P<.05). The IL-10 level increased in the PCG group (P<.05). The OPG level was similar in both groups (P>.05). The number of mature osteoclasts (TRAP-positive multinucleated cells) was lower in PCG group when compared to the CG (P<.05). Conclusion Probiotic Complex modulates inflammation and bone resorption in apical periodontitis.

Influence of the Vehicle on the Tissue Reaction and Biomineralization of Fast Endodontic Cement

ABSTRACT Objective: To investigate the tissue response and the biomineralization ability of CER prepared with epoxy resin or water compared to Mineral Trioxide Aggregate (MTA). Material and Methods: Polyethylene tubes containing materials or empty tubes for control were inserted into the subcutaneous tissues of 30 rats. After 7, 15, 30, 60, and 90 days, the rats were killed and the tubes were removed for analysis using hematoxylin-eosin staining, von Kossa staining, and under polarized light. Inflammation was graded through a score system; the thickness of the fibrous capsule was classified as thin or thick; the biomineralization ability was recorded as present or absent. The results were statistically analyzed using the Kruskal-Wallis test (p<0.05). Results: Histologic analysis performed after 7 and 15 days for CER prepared with epoxy resin or water and for MTA showed moderate inflammation and a thick fibrous capsule (p>0.05). After 30, 60, and 90 days, mild inflammation, and a thin fibrous capsule were observed in all groups (p>0.05). Conclusion: All materials had structures positive for von Kossa and birefringent to polarized light. CER epoxy resin showed biocompatibility and biomineralization similar to CER water and MTA.

Estudo in vitro da influência de diferentes plugs coronários sobre o remanescente da obturação, após preparo para pino, na retenção de pinos metálicos fundidos / In vitro assessment of the influence of different protection plugs over obturation remnant space, after post preparation, on the retention of cast metal posts

Objetivo: Avaliar a influência de diferentes plugs de proteção, acomodados sobre o remanescente da obturação após preparo para pino, na retenção de pinos metálicos fundidos. Métodos: Cinquenta dentes bovinos foram decoronados, manualmente instrumentados até a lima manual Kerr #80 e obturados. A desobturação parcial de 10mm do conduto foi realizada com uma broca Largo e os grupos foram divididos de acordo com os diferentes materiais utilizados como plugs (n=10): Grupo I (Controle, sem plug); Grupo II (plug de Coltosol®); Grupo III (plug, em consistência de massa, de Sealapex® + óxido de zinco); Grupo IV (plug de etil-cianoacrilato); e Grupo V (plug de fosfato de zinco). Uma camada de 1mm de espessura dos diferentes plugs (Grupos II, III, IV ou V) foi acomodada sobre a obturação remanescente. Os espécimes foram selados e armazenados em 100% de umidade, por 7 dias. Após moldagem do conduto, foram confeccionados pinos metálicos fundidos e cimentados com fosfato de zinco. Os espécimes permaneceram em câmara úmida por 45 dias antes do teste de tração, realizado em uma máquina universal de ensaios. Os valores foram expressos em Mega pascal (MPa) e submetidos aos testes ANOVA e Tukey (p<0,05). Resultados: O etilcianoacrilato diminuiu a retenção dos pinos metálicos fundidos (p<0,01). Não houve diferença entre os outros grupos (p>0,05), semelhante- mente ao controle. Conclusão: A proteção da obturação com plugs confeccionados com etil-cianoacrilato prejudica a retenção de pinos metálicos fundidos cimentados com fosfato de zinco, enquanto Sealapex® acrescido de óxido de zinco, fosfato de zinco endurecido ou Coltosol® não interferem na adesividade (AU).

Cytotoxicity, inflammation, biomineralization, and immunoexpression of IL-1β and TNF-α promoted by a new bioceramic cement

Abstract Aim To evaluate the cytotoxicity, biocompatibility and mineralization capacity of BIO-C PULPO, and MTA. Methodology L929 fibroblasts were cultured and MTT assay was used to determine the material cytotoxicity on 6, 24, and 48 h. A total of 30 male rats (Wistar) aged between 4 and 6 months, weighing between 250 and 300 g were used. Polyethylene tubes containing BIO-C PULPO, MTA, and empty tubes were implanted into dorsal connective tissue. After the experimental periods (7, 15, 30, 60, and 90 days) the tubes were histologically analyzed using hematoxylin-eosin (H&E), immunolabeling of IL-1β and TNF-α, and von Kossa staining, or without staining for polarized light analysis. The average number of inflammatory cells was quantified; the mineralization assessment was determined by the area marked in μm2 and semiquantitative immunolabeling analyses of IL-1β and TNF-α were performed. Then, data underwent statistical analysis with a 5% significance level. Results It was observed that BIO-C PULPO and MTA presented cytocompatibility at 6, 24, and 48 similar or higher than control for all evaluated period. On periods 7 and 15 days, BIO-C PULPO was the material with the highest number of inflammatory cells (p<0.05). On periods 30, 60, and 90 days, BIO-C PULPO and MTA presented similar inflammatory reactions (p>0.05). No statistical differences were found between Control, BIO-C PULPO, and MTA for immunolabeling of IL-1β and TNF-α in the different periods of analysis (p<0.05). Positive von Kossa staining and birefringent structures under polarized light were observed in all analyzed periods in contact with both materials, but larger mineralization area was found with BIO-C PULPO on day 90 (p<0.05). Conclusion BIO-C PULPO was biocompatible and induced mineralization similar to MTA.

Comparison between calcium hydroxide mixtures and mineral trioxide aggregate in primary teeth pulpotomy: a randomized controlled trial

Abstract Objectives: To evaluate the effect of calcium hydroxide (CH) associated with two different vehicles as a capping material for pulp tissue in primary molars, compared with mineral trioxide aggregate (MTA). Methodology: Forty-five primary mandibular molars with dental caries were treated by conventional pulpotomy using one of the following materials: MTA only (MTA group), CH with saline (CH+saline group) and CH with polyethylene glycol (CH+PEG group) (15 teeth/group). Clinical and periapical radiographic examinations of the pulpotomized teeth were performed 3, 6, and 12 months after treatment. Data were tested by chi-squared analysis and a multiple comparison post-test. Results: The MTA group showed both clinical and radiographic treatment success in 14/14 teeth (100%), at all follow-up appointments. By clinical evaluation, no teeth in the CH+saline and CH+PEG groups had signs of mobility, fistula, swelling or inflammation of the surrounding gingival tissue. However, in the CH+saline group, radiographic analysis detected internal resorption in up to 9/15 teeth (67%), and inter-radicular bone resorption and furcation radiolucency in up to 5/15 teeth (36%), from 3 to 12 months of follow-up. In the CH+PEG group, 2/11 teeth (18%) had internal resorption and 1/11 teeth (9%) presented bone resorption and furcation radiolucency at all follow-up appointments. Conclusion: CH with PEG performed better than CH with saline as capping material for pulpotomy of primary teeth. However, both combinations yielded clinical and radiographic results inferior to those of MTA alone.

Hypertension affects the biocompatibility and biomineralization of MTA, High-plasticity MTA, and Biodentine®

Abstract This study evaluated the effect of hypertension on tissue response and biomineralization capacity of white Mineral Trioxide Aggregate (MTA), High-plasticity MTA (MTA HP), and Biodentine® (BDT) in rats. Polyethylene tubes filled with MTA, MTA HP, BDT, and the control group (empty tubes) were placed into the dorsal subcutaneous tissue of 32 male rats (16 normotensive (NT) and 16 hypertensive rats - 8 per group). After 7 and 30 days, the polyethylene tubes surrounded by connective tissue were removed, fixed, and embedded in histological resin. The mean number of inflammatory cells was estimated in HE-stained sections, biomineralization was quantified as area (µm2) by Kossa (VK) staining, and examination by polarized light (LP) microscopy was performed. The differences amongst the groups were analyzed statistically by the Mann-Whitney or Student's t test, according to Shapiro-Wilk test of normality (p < 0.05). The inflammatory responses to all materials were greater in hypertensive rats than in NT rats (p < 0.05). Positive VK staining in MTA and BDT were more pronounced in NT rats at 7 and 30 days (p < 0.05). Birefringent structures in LP for MTA, MTA HP, and BDT were more pronounced in NT rats at 7 days (p<0.05). In rats, hypertension was able to increase inflammatory infiltrate and decrease biomineralization of the tested materials.

Omega 3 fatty acids reduce the triglyceride levels in rats with apical periodontitis

Abstract The aim of this study was to evaluate the influence of the prophylactic and therapeutic supplementation with omega 3 polyunsaturated fatty acids (w-3 PUFAs) on the lipid profile and periapical bone resorption in rats with apical periodontitis. Forty male rats were divided into groups: control rats (C), rats treated with w-3 PUFAs (C+O), rats with pulp exposure-induced apical periodontitis (AP), and rats with AP treated with w-3 PUFAs (AP+O). The administration of w-3 PUFAs was carried out orally once a day for 15 days before pulp exposure and, subsequently, for an additional 30 days after pulp exposure. AP was induced by exposing pulpal tissues to the oral environment. The samples were collected after 30 days. Triglycerides and cholesterol levels were enzymatically measured using the Trinder method. The jaws were collected and submitted for histological analysis. Two-way analysis of variance and Kruskal-Wallis tests were used for statistical analysis, and the significance was set at p<0.05. The triglyceride levels of the AP group were significantly higher than those of the C, C+O and AP+O groups (p<0.05). However, the difference in the cholesterol levels among the groups was not significant (p>0.05). Rats with AP showed larger areas of bone resorption as well as higher inflammatory intensity compared with rats with AP supplemented with w-3 PUFAs. It may be concluded that the presence of multiple AP foci increased the triglyceride levels. In addition, omega 3 supplementation might reduce these levels in rats with AP, as well as the bone resorption areas of periapical tissues.

Resumo O objetivo deste estudo foi avaliar a influência da suplementação profilática e terapêutica com os ácidos graxos ômega-3 no perfil lipídico e na reabsorção óssea, em ratos com periodontite apical. Quarenta ratos machos foram divididos em grupos: ratos controle (C), ratos tratados com ácidos graxos ômega-3 (C+O), ratos com periodontite apical induzida por meio de exposição pulpar (PA), ratos com PA tratados com ácidos graxos ômega-3 (PA+O). A administração do ômega-3 foi realizada oralmente, uma vez ao dia durante 15 antes da exposição pulpar e, subsequentemente, por mais 30 dias depois da exposição pulpar. A PA foi induzida por meio da exposição do tecido pulpar ao ambiente oral. Após 30 dias, os ratos foram mortos e os níveis de triglicérides e colesterol foram mensurados pelo método enzimático de Trinder. As mandíbulas foram coletadas e submetidas à análise histológica. Análise de variância de dois fatores e teste de Kruskal-Wallis foram utilizados para análise estatística, e o nível de significância foi de p < 0,05. Os níveis de triglicérides do grupo PA foram significativamente maiores que dos grupos C, C+O e PA+O (p<0,05). Entretanto, não houve diferença significativa nos níveis de colesterol entre os grupos (p>0,05). Ratos com PA apresentaram maior área de reabsorção óssea bem como maior intensidade no infiltrado inflamatório comparados aos ratos com PA suplementados com ômega-3. Pode-se concluir que a presença de múltiplos focos de PA aumentou os níveis de triglicérides. Além disso, a suplementação com ômega-3 pode reduzir estes níveis em ratos com PA, bem como a área de reabsorção óssea dos tecidos periapicais.

Effects of mineral trioxide aggregate, BiodentineTM and calcium hydroxide on viability, proliferation, migration and differentiation of stem cells from human exfoliated deciduous teeth

Abstract Objective: The aim of the study was to evaluate the effects of the capping materials mineral trioxide aggregate (MTA), calcium hydroxide (CH) and BiodentineTM (BD) on stem cells from human exfoliated deciduous teeth (SHED) in vitro. Material and Methods: SHED were cultured for 1 - 7 days in medium conditioned by incubation with MTA, BD or CH (1 mg/mL), and tested for viability (MTT assay) and proliferation (SRB assay). Also, the migration of serum-starved SHED towards conditioned media was assayed in companion plates, with 8 μm-pore-sized membranes, for 24 h. Gene expression of dentin matrix protein-1 (DMP-1) was evaluated by reverse-transcription polymerase chain reaction. Regular culture medium with 10% FBS (without conditioning) and culture medium supplemented with 20% FBS were used as controls. Results: MTA, CH and BD conditioned media maintained cell viability and allowed continuous SHED proliferation, with CH conditioned medium causing the highest positive effect on proliferation at the end of the treatment period (compared with BD and MTA) (p<0.05). In contrast, we observed increased SHED migration towards BD and MTA conditioned media (compared with CH) (p<0.05). A greater amount of DMP-1 gene was expressed in MTA group compared with the other groups from day 7 up to day 21. Conclusion: Our results show that the three capping materials are biocompatible, maintain viability and stimulate proliferation, migration and differentiation in a key dental stem cell population.

Factors affecting the periapical healing process of endodontically treated teeth

Abstract Tissue repair is an essential process that reestablishes tissue integrity and regular function. Nevertheless, different therapeutic factors and clinical conditions may interfere in this process of periapical healing. This review aims to discuss the important therapeutic factors associated with the clinical protocol used during root canal treatment and to highlight the systemic conditions associated with the periapical healing process of endodontically treated teeth. The antibacterial strategies indicated in the conventional treatment of an inflamed and infected pulp and the modulation of the host's immune response may assist in tissue repair, if wound healing has been hindered by infection. Systemic conditions, such as diabetes mellitus and hypertension, can also inhibit wound healing. The success of root canal treatment is affected by the correct choice of clinical protocol. These factors are dependent on the sanitization process (instrumentation, irrigant solution, irrigating strategies, and intracanal dressing), the apical limit of the root canal preparation and obturation, and the quality of the sealer. The challenges affecting the healing process of endodontically treated teeth include control of the inflammation of pulp or infectious processes and simultaneous neutralization of unpredictable provocations to the periapical tissue. Along with these factors, one must understand the local and general clinical conditions (systemic health of the patient) that affect the outcome of root canal treatment prediction.

Diabetic Rats Present High Mean Platelet Count in the Presence of Oral Infections

Abstract Platelet count is associated with inflammatory diseases like diabetes mellitus (DM), which in turn, is related in a bidirectional manner with apical periodontitis and periodontal disease. The aim of this study was to evaluate the effects of apical periodontitis and/or periodontal disease on mean platelet count in a rat model of diabetes mellitus. Eighty Wistar rats were randomly divided into 8 groups (n=10): control (C), apical periodontitis (AP), periodontal disease (PD), apical periodontitis with periodontal disease (AP-PD), diabetes mellitus (DM), diabetes mellitus with apical periodontitis (DM-AP), diabetes mellitus with periodontal disease (DM-PD) and diabetes mellitus with apical periodontitis and periodontal disease (DM-AP-PD). Rats were anesthetized and DM was induced with a single dose of streptozotocin diluted in citrate buffer solution. After 6 days, the DM was confirmed. The animals were sedated and apical periodontitis was induced by dental exposure and periodontal disease was induced by periodontal ligature. After 30 days, animals were anesthetized and the blood was collected by cardiac puncture. Samples were processed and the mean platelet count was obtained. Data were tabulated and subjected to statistical analysis (p<0.05). Diabetic rats had higher mean glycemic levels compared with nondiabetic rats at 6 and 36 days after DM induction (p<0.05). The DM-PD and DM-PD-AP groups showed increased mean platelet count compared to control and AP groups (p<0.05). The periodontal disease alone or associated with apical periodontitis influence mean platelet count in a rat model of diabetes mellitus.

Resumo A contagem de plaquetas está associada a doenças inflamatórias como a diabetes mellitus (DM), que, por sua vez, está relacionada de forma bidirecional com periodontite apical e com a doença periodontal. O objetivo deste estudo foi avaliar os efeitos da periodontite apical e/ou da doença periodontal na contagem de plaquetas utilizando o modelo de rato para DM. Oitenta ratos Wistar foram divididos aleatoriamente em 8 grupos (n=10): controle (C), periodontite apical (AP), doença periodontal (PD), periodontite apical com doença periodontal (AP-PD), diabetes mellitus (DM), diabetes mellitus com periodontite apical (DM-AP), diabetes mellitus com doença periodontal (DM-PD) e diabetes mellitus com periodontite apical e doença periodontal (DM-AP-PD). Os ratos foram anestesiados e a DM foi induzida com uma dose única de estreptozotocina diluída na solução tampão citrato. Após 6 dias, o DM foi confirmada. Os animais foram sedados e a periodontite apical foi induzida pela exposição dentária e a doença periodontal foi induzida por ligadura periodontal. Após 30 dias, os animais foram anestesiados e o sangue foi coletado por punção cardíaca. As amostras foram processadas e a contagem média de plaquetas foi obtida. Os dados foram tabulados e submetidos a análise estatística (p <0,05). Os ratos diabéticos apresentaram níveis glicêmicos médios mais elevados em comparação com ratos não diabéticos aos 6 e 36 dias após a indução da DM (p <0,05). Os grupos DM-PD e DM-PD-AP mostraram aumento da contagem média de plaquetas em comparação com os grupos controle e AP (p <0,05). A doença periodontal isolada ou associada à periodontite apical influencia na contagem de plaquetas em modelo de rato para diabetes mellitus.

Marginal leakage of temporary restoration after intraradicular post preparation with or without waterproofing / Infiltração marginal de restauração temporária após o preparo de pino intrarradicular com ou sem impermeabilização

Objective: This study evaluated the leakage volume of 1% Rhodamine B which received or not an internal waterproofing material. The hypothesis is that the waterproofing reduces microleakage. Material and Methods: Forty-two human teeth were selected for this study. After access, preparation, and filling of root canals, the teeth were divided into 3 groups: GI ­ sealed with Cimpat Blanc®, without intraradicular post/core preparation; GII - sealed with Cimpat Blanc®, with intraradicular post/core preparation, and GIII ­ sealed with Cimpat Blanc®, with intraradicular post/core preparation and internal waterproofing material with ethyl cyanoacrylate. T-test was used to analyze difference between initial and final weight and there was difference (p < 0.05). To analyze infiltration of the colorant, the volume was the comparison variable. Results: Shapiro Wilktest was applied and showed normal distribution of the variables. ANOVA (p = 0.0013 / p< 0.5). Conclusion: In endodontically treated teeth receiving temporary restoration, the use of ethyl cyanoacrylate as internal waterproofing material is effective in preventing microleakage. (AU)

Objetivos: Este estudo avaliou o volume de infiltração de Rhodamine B 1% com ou sem impermeabilização interna. A hipótese é que a impermeabilização reduz a microinfiltração. Material e Métodos: Foram selecionados 42 dentes humanos para este estudo. Após o acesso, o preparo e a obturação dos canais radiculares, os dentes foram divididos em 3 grupos: GI - sem preparo para núcleo intrarradicular e selado com Cimpat Blanc®; GII - com preparo para núcleo intrarradicular e selado com Cimpat Blanc®, e GIII - com preparo para núcleo intrarradicular, impermeabilizado internamente com cianoacrilato de etila e selado com Cimpat Blanc®. O teste T foi utilizado para analisar a diferença entre o peso inicial e o peso final (p < 0,05). Para analisar a infiltração do corante, o volume era a variável de comparação. Resultados: o teste de Shapiro Wilk foi aplicado e mostrou distribuição normal das variáveis. O teste ANOVA (p = 0,0013 / p < 5%) foi aplicado e determinou uma diferença estatística entre os grupos. Ao comparar os grupos em conjunto, GIII mostra a menor taxa de vazamento quando comparado aos outros grupos, sendo estatisticamente diferente (teste de Tukey - p < 0,5). Conclusão: Nos dentes endodonticamente tratados com restauração temporária, o uso de cianoacrilato de etila como material impermeabilizante interno é eficaz na prevenção da microinfiltração (AU)

Penetration Capacity, Color Alteration and Biological Response of Two In-office Bleaching Protocols

Abstract Hydrogen peroxide (H2O2) penetrates into the dental hard tissues causing color alteration but also alterations in pulpal tissues. Hard-tissue penetration, color alteration and the pulp response alterations were evaluated for two in-office bleaching protocols with H2O2. For trans-enamel/dentin penetration and color alteration, discs of bovine teeth were attached to an artificial pulp chamber and bleached according to the groups: BLU (20% H2O2 - 1x50 min, Whiteness HP Blue); MAX (35% H2O2 - 3x15 min, Whiteness HP Maxx); Control (1x50 min, placebo). Trans-enamel/dentin penetration was quantified based on the reaction of H2O2 with leucocrystal violet and the color analyzed by CIELab System. Twenty Wistar rats were divided into two groups (BLU and MAX) and their maxillary right molars were treated according to the same protocols of the in vitro study; the maxillary left molars were used as controls. After 2 days, the animals were killed and their maxillae were examined by light microscopy. The inflammation of pulp tissue was scored according to the inflammatory infiltrate (1, absent; 2, mild; 3, moderate; 4, severe/necrosis). Data were analyzed by statistical tests (α=0.05). MAX showed higher trans-enamel/dentinal penetration of H2O2 (p<0.05). The color alteration was similar for both groups (p>0.05), and different when compared to Control group (p<0.05). MAX showed severe inflammation in the upper thirds of the coronal pulp, and BLU showed moderate inflammation (p<0.05). In-office bleaching protocols using lower concentrations of hydrogen peroxide should be preferred due to their reduced trans-enamel/dentinal penetration since they cause less pulp damage and provide same bleaching efficiency.

Resumo O peróxido de hidrogênio (H2O2) é capaz de penetrar pelos tecidos dentários, alterando a coloração destes, e causar danos a polpa. Este estudo avaliou a penetração por esmalte e dentina, a alteração de cor e a reposta tecidual pulpar, provocadas pelo uso de duas concentrações de H2O2 em protocolos de clareação dentária de consultório. Discos de dentes bovinos em câmaras pulpares artificiais receberam géis clareadores para avaliação da penetração por esmalte e dentina e da alteração de cor, formando os grupos: BLU (H2O2 20% - 1x50 min, Whiteness HP Blue); MAX (H2O2 35% - 3x15 min, Whiteness HP Maxx); e Controle (gel placebo - 1x50 min). A penetração por esmalte e dentina foi quantificada baseada na reação do H2O2 com o corante violeta leucocristal, e a alteração de cor foi analisada pelo sistema CIELab. Vinte ratos Wistar foram divididos em dois grupos (BLU e MAX), e tiveram os molares direito superiores tratados com os mesmos protocolos do estudo in vitro; os molares superiores do lado esquerdo serviram de controle. Após 2 dias, os animais foram eutanasiados e as maxilas examinadas por microscopia de luz. Foram atribuídos escores ao infiltrado inflamatório (1, ausente; 2, leve; 3, moderado; 4 severo ou necrose). Os dados foram submetidos a testes estatísticos (=0,05). O grupo MAX apresentou maior penetração de H2O2 por esmalte e dentina (p<0,05). A alteração de cor foi semelhante nos grupos clareados (p>0,05), mas diferente quando comparados grupos clareados com controle (p<0,05). MAX apresentou inflamação severa nos terços superiores da polpa coronária, e BLU apresentou inflamação moderada (p<0,05). Assim, protocolo para procedimento clareador de consultório utilizando baixas concentrações de H2O2 deve ser de escolha na clínica, por reduzir a penetração por esmalte e dentina, causando menos danos à polpa, e proporcionar mesma eficiência clareadora.

Evaluation of an experimental rat model for comparative studies of bleaching agents

ABSTRACT Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents.

Evaluation of an experimental rat model for comparative studies of bleaching agents

ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.

Influence of diabetes mellitus on the mineralization ability of two endodontic materials

Abstract The aim of this study was to evaluate the influence of diabetes mellituson tissue response and mineralization ability of Sealapex®and MTA Fillapex® sealers. Twenty-four Wistar rats were divided into two groups: diabetic and non-diabetic. The materials were placed in polyethylene tubes and implanted into dorsal connective tissue of rats for 7 and 30 days. Six animals from each group received injection of calcein, alizarin, and oxytetracycline on days 7, 14, and 21, respectively. The animals were killed after 7 and 30 days and specimens were prepared for histologic analysis by staining with hematoxylin and eosin or Von Kossa or left unstained for polarized light or fluorescence microscopy. On day 7, inflammatory reactions were characterized. Moderate inflammatory responses were observed for all groups and on day 30, a mild inflammatory response against MTA Fillapex® and a moderate inflammatory response against Sealapex® were observed. Von Kossa-positive structures were observed in response to both materials and birefringent structures were observed upon polarized light analysis; these had no relation to the diabetic condition (p > 0.05). The fluorescence intensity was unaffected in diabetic rats (p > 0.05). In conclusion, diabetes mellitus did not influence the tissue response or mineralization stimulated by Sealapex® or MTA Fillapex®.

Biocompatibility and biomineralization assessment of bioceramic-, epoxy-, and calcium hydroxide-based sealers

Abstract Obturation of the root canal system aims to fill empty spaces, promoting hermetic sealing and preventing bacterial activity in periapical tissues. This should provide optimal conditions for repair, stimulating the process of biomineralization. An endodontic sealer should be biocompatible once it is in direct contact with periapical tissues. The aim of this study was to evaluate the rat subcutaneous tissue response to implanted polyethylene tubes filled with Smartpaste Bio, Acroseal, and Sealapex and investigate mineralization ability of these endodontic sealers. Forty Wistar rats were assigned to the three sealers groups and control group, (n = 10 animals/group) and received subcutaneous implants containing the test sealers, and the control group were implanted with empty tubes. After days 7, 15, 30, and 60, animals were euthanized and polyethylene tubes were removed with the surrounding tissues. Inflammatory infiltrate and thickness of the fibrous capsule were histologically evaluated. Mineralization was analyzed by Von Kossa staining and polarized light. Data were tabulated and analyzed via Kruskal-Wallis and Dunn's test. All tested materials induced a moderate inflammatory reaction in the initial periods. Smartpaste Bio induced the mildest inflammatory reactions after day 15. No difference was observed among groups after days 30 or 60. Von Kossa-positive staining and birefringent structures observed under polarized light revealed a larger mineralization area in Sealapex-treated animals followed by Smartpaste Bio-treated animals. At the end of the experiment, all tested sealers were found to be biocompatible. All sealers induced biomineralization, except Acroseal, which induced a mild tissue reaction.

Relationship between hypertension and periapical lesion: an in vitro and in vivo study

Abstract The aim of this study was to compare potential aspects of periapical lesion formation in hypertensive and normotensive conditions using hypertensive (BPH/2J) and wild-type control (BPN/3J) mice. The mandibular first molars of both strains had their dental pulp exposed. At day 21 the mice were euthanized and right mandibular molars were used to evaluate the size and phenotype of apical periodontitis by microCT. Proteins were extracted from periapical lesion on the left side and the expressions of IL1α, IL1β and TNFα were analyzed by ELISA. Bone marrow stem cells were isolated from adult mice femurs from 2 strains and osteoclast differentiation was evaluated by tartrate-resistant acid phosphatase (TRAP) in vitro. The amount of differentiated osteoclastic cells was nearly double in hypertensive mice when compared to the normotensive strain (p < 0.03). Periapical lesion size did not differ between hypertensive and normotensive strains (p > 0.7). IL1α, IL1β and TNFα cytokines expressions were similar for both systemic conditions (p > 0.05). Despite the fact that no differences could be observed in periapical lesion size and cytokines expressions on the systemic conditions tested, hypertension showed an elevated number of osteoclast differentiation.

Antimicrobial action of calcium hydroxide-based endodontic sealers after setting, against E. faecalis biofilm

Abstract Enterococcus faecalis are gram positive bacteria that can mostly resist endodontic therapy, inducing persistent infection in the root canal system. Endodontic sealers with antimicrobial activity may help eliminate residual microorganisms that survive endodontic treatment. The present study aimed at comparing the antimicrobial activity of Acroseal, Sealapex and AH Plus endodontic sealers in an in vitro biofilm model. Bovine dentin specimens (144) were prepared, and twelve blocks for each sealer and each experimental time point (2, 7 and 14 days) were placed and left in contact with plates containing inoculum of E. faecalis (ATCC 51299), to induce biofilm formation. After 14 days, the samples were transferred to another plate with test sealers and kept at 37°C and 5% CO2 for 2, 7 and 14 days. The specimens without sealers were used as a control for each period. The samples were agitated in a sonicator after each experiment. The suspensions were agitated in a vortex mixer, serially diluted in saline, and triple plated onto m-Enterococcus agar. Colonyforming units were counted, and the data were statistically analyzed using ANOVA, Shapiro-Wilk and Kruskal-Wallis one-way tests (p < 0.05) to determine antimicrobial potential. Sealapex showed significant differences at all the experimental time points, in comparison with all the other groups. AH Plus and Acroseal showed antimicrobial activity only on the 14th experimental day. Neither of the sealers tested were able to completely eliminate the biofilm. Sealapex showed the highest antimicrobial activity in all the experimental periods. The antimicrobial activity of all the sealers analyzed increased over time.

Efeito de diferentes tratamentos de superfície sobre a resistência de união de pinos de fibra ao canal radicular / Effect of different surface treatments on the push-out bond strength of fiber posts to root canal

O objetivo do presente estudo foi avaliar o efeito de diferentes tratamentos de superfície sobre a resistência de união de pinos de fibra ao canal radicular. Quarenta e quatro pré-molares inferiores humanos, recém-extraídos, foram instrumentados utilizando-se o sistema rotatório K3®. Os canais foram obturados com guta-percha e cimento Sealapex®. Após preparo para pino, foi realizado um dos quatro seguintes tipos de tratamento de superfície intrarradicular: irrigação com cloreto de sódio (NaCl) a 0,9%, hipoclorito de sódio (NaOCl) a 2,5%, digluconato de clorexidina (CHX) a 2% ou ácido etilenodiaminotetracético (EDTA) a 17%. Pinos de fibra foram cimentados utilizando-se o cimento resinoso RelyX® (Unicem). A partir da parte coronária de cada raiz, foram obtidas três fatias de 1mm de espessura. Foi realizado o teste de cisalhamento por extrusão (Push-out) utilizando uma máquina de ensaios universal a 0,5mm/min. Os dados obtidos foram tabulados e submetidos à análise estatística por meio da análise de variância e do teste de Tukey (p < 0,05). Os resultados mostraram que o tratamento com NaOCl ou EDTA aumentou a resistência de união à dentina, porém sem diferenças do ponto de vista estatístico. Foi possível concluir que a força de união do pino de fibra ao canal radicular não foi significantemente afetada pelo tratamento de superfície com NaOCl a 2,5%, CHX a 2% ou EDTA a 17%.