Cytotoxicity and biocompatibility of a new bioceramic endodontic sealer containing calcium hydroxide

Abstract: This study evaluated the cytotoxicity and biocompatibility of a new bioceramic endodontic sealer (i.e., Sealer Plus BC) in comparison with those of MTA Fillapex and AH Plus. L929 fibroblasts were cultured and Alamar Blue was used to evaluate cell viability of diluted extracts (1:50, 1:100, and 1:200) from each sealer at 24 h. Polyethylene tubes that were filled with material or empty (as a control) were implanted in the subcutaneous tissue of rats. The rats were killed after 7 and 30 d (n = 8), and the tubes were removed for histological analysis. Parametric data was analyzed using a one-way ANOVA test, and nonparametric data was analyzed via the Kruskal-Wallis test followed by the Dunn test (p < 0.05). A reduction in cell viability was observed in the extracts that were more diluted for Sealer Plus BC when compared to that of Control and AH Plus (p < 0.05). However, the 1:50 dilution of the Sealer Plus BC was similar to that of the Control (p > 0.05). Conversely, more diluted extracts of MTA Fillapex (1:200) and AH Plus (1:100 and 1:200) were similar to the Control (p > 0.05). Histological analysis performed at 7 d did not indicate any significant difference between tissue response for all materials, and the fibrous capsule was thick (p > 0.05). At 30 d, Sealer Plus BC was similar to the Control (p > 0.05) and MTA Fillapex and AH Plus exhibited greater inflammation than the Control (p < 0.05). The fibrous capsule was thin for the Control and for most specimens of Sealer Plus BC and AH Plus. Thus, Sealer Plus BC is biocompatible when compared to MTA Fillapex and AH Plus, and it is less cytotoxic when less-diluted extracts are used.

Demineralized bone matrix and calcium-phosphate cement in bone regeneration in rats

Abstract Purpose: To compare bone regeneration in critical-sized defects in rat calvarium using demineralized bone matrix and calcium phosphate cement. Methods: Thirty Wistar rats were divided into 3 groups of 10 animals each. Two defects of 5-mm were made in the parietal bones of each animal. Group I had calcium phosphate cement placed in the experimental defect, Group II had filled with demineralized bone matrix and Group III had with the combination of the matrix and cement in equal parts. All animals had one defect left unfilled to serve as controls. Five animals in each group were sacrificed at 4 and 8 weeks. Histomorphometric analysis was used to quantify the amount of new bone within the defects. Results: The results showed that demineralized bone matrix-treated defects had significantly more new bone at 4 weeks compared to calcium phosphate cement-treated defects (p=0.03) and also had significantly more new bone at 8 weeks compared to unfilled defects (p=0.04). Conclusions: The demineralized bone matrix was superior to calcium phosphate cement in bone regeneration. It seems that calcium phosphate cement acted by inhibiting the osteogenesis when associated with a demineralized bone matrix and this combination should not be recommended.

Bacteriology of deep carious lesions underneath amalgam restorations with different pulp-capping materials - an in vivo analysis

Microorganisms remaining in dentin following cavity preparation may induce pulp damage, requiring the use of pulp-capping agents with antimicrobial activity underneath permanent restorations. OBJECTIVE: The aims of this study were to analyze the bacteriological status of carious dentin and to assess the efficacy of different base underneath silver amalgam restorations. MATERIAL AND METHODS: This study was conducted on 50 patients aged 13 to 30 years. Sterile swabs were used to take samples after cavity preparation, which was assessed by microbiological culture to identify the microorganisms present. Following this, cavities were restored with silver amalgam, using one of the materials being investigated, as the base: calcium hydroxide (Group II), polyantibiotic paste (Group III), a novel light-cured fluoride-releasing hydroxyapatite-based liner (Group IV) and mineral trioxide aggregate - MTA (Group V). In Group I, the cavities were restored with silver amalgam, without any base. After 3 months, the amalgam was removed and samples taken again and analyzed for the microbial flora. RESULTS: Lactobacilli were the most commonly isolated microorganisms in the samples of carious dentin. Groups IV and V showed negative culture in the 3-month samples. There was no statistically significant difference between Groups I, II and III. There was no significant difference between Groups IV and V (p>0.05). Both Groups IV and V showed significantly better results when compared to Groups I, II and III (p<0.05). CONCLUSIONS: The hydroxyapatite-based liner and MTA performed significantly better in terms of antibacterial activity than the other materials.

Pulp capping materials exert an effect on the secretion of IL-1β and IL-8 by migrating human neutrophils

Pulp repair is a complex process whose mechanisms are not yet fully understood. The first immune cells to reach the damaged pulp are neutrophils that play an important role in releasing cytokines and in phagocytosis. The objective of this study was to analyze the effect of different pulp-capping materials on the secretion of interleukin-1 beta (IL-1β) and interleukin-8 (IL-8) by migrating human neutrophils. Neutrophils were obtained from the blood of three healthy donors. The experimental groups were calcium hydroxide [Ca(OH)2], an adhesive system (Single Bond), and mineral trioxide aggregate (MTA). Untreated cells were used as control. Transwell chambers were used in performing the assays to mimic an in vivo situation of neutrophil chemotaxis. The pulp-capping materials were placed in the lower chamber and the human neutrophils, in the upper chamber. The cells were counted and the culture medium was assayed using ELISA kits for detecting and quantifying IL-1β and IL8. The data were compared by ANOVA followed by Tukey's test (p < 0.05). The secretion of IL-8 was significantly higher in all groups in comparison to the control group (p < 0.05). The adhesive system group showed higher IL-8 than the MTA group (p < 0.05). The secretion of IL-1β was significantly greater only in the MTA group (p < 0.001). It was concluded that only MTA is able to improve the secretion of IL-1β, and all materials tested increased IL-8 secretion. These results combined with all the other biological advantages of MTA indicate that it could be considered the material of choice for dental pulp capping.

An injectable cement: synthesis, physical properties and scaffold for bone repair.

Micro-invasive bone grafting is to deliver bone graft materials to the desired site through local puncturation and injection. It has many advantages such as little injury, simple procedures and high efficiency of osteogenesis. Limited sources of graft materials and complicated procedures are the main factors affecting the development of the technique. Therefore, to prepare a stable, economical, efficient and easy-to-use liquid graft material is crucial for the development of the technique. PURPOSE: The potential efficacy of an injectable calcium phosphate cement's handling properties and scaffold for bone repair performance was evaluated in a rabbit femoral condyles model. STUDY DESIGN: A comparative study was conducted between a new cement and a commercially available calcium phosphate cement. MATERIALS AND METHODS: The new cement and commercially available calcium-phosphate cements were compared in terms of the setting time, injection pressure, particle size and compressive strength. Then the cements were delivered to rabbit femoral condyles through local injection and then degradation of cements and bone formation were observed regularly after operation. RESULTS: The new injectable cement was superior to currently used cements in terms of permitted manipulation time, injection pressure, particle size, postoperative degradation and efficacy of scaffold for bone repair; nevertheless, the new cement was slightly inferior to currently used cements in compressive strength and the final setting time. CONCLUSIONS: The new injectable cement is more suitable for the clinical study of micro-invasive bone grafting. It allows a brand new bone grafting procedure and provides a new graft material and thus merits further development and wider application.

In vitro evaluation of the effectiveness of the chemomechanical preparation against Enterococcus faecalis after single- or multiple-visit root canal treatment

The purpose was to assess the elimination of Enterococcus faecalis in vitro in human mandibular premolars after chemomechanical preparation with or without the use of a calcium hydroxide dressing. After 60 days of contamination with E. faecalis, the root canals were prepared using the Crown-Down technique combined with 2 percent chlorhexidine gel irrigation. Then, the specimens were divided into two experimental groups, treated in a single visit or in multiple visits, and two control groups. The multiple-visit group received a dressing with calcium hydroxide for 14 days (CalenTM) and the single-visit group did not receive any medication. In the two control groups, the canals were filled with BHI after chemomechanical preparation with 2 percent chlorhexidine gel or distilled water. Microbial samples were taken from the root canals for colony forming unit count for each phase of the treatment using sterile paper points inside the root canal lumen. Data were ranked and analyzed by the Kruskal-Wallis statistical test. The residual microbial colonies were then assessed. The results showed that chemomechanical preparation using 2 percent chlorhexidine gel with no intra-canal dressing reduced by 100 percent the E. faecalis contamination of the root canal lumen. The calcium-hydroxide group that received the 14-day intra-canal dressing allowed a small number of bacteria to grow between visits, but without statistical differences between groups.

Objetivou-se avaliar in vitro a eliminação do Enterococcus faecalis em pré-molares inferiores humanos após o preparo químico-mecânico seguido ou não de curativo de hidróxido de cálcio. Após 60 dias de contaminação com E. faecalis os canais radiculares foram preparados utilizando-se a técnica coroa-ápice associada à irrigação com clorexidina em gel a 2 por cento. Posteriormente os espécimes foram divididos em dois grupos experimentais, tratados em uma ou duas sessões, e dois grupos controles. O grupo tratado em duas sessões recebeu medicação intracanal de hidróxido de cálcio por 14 dias (CalenTM) e o grupo de sessão única não recebeu medicação. Nos dois grupos controles, após o preparo químico-mecânico com clorexidina em gel a 2 por cento ou água destilada, os canais foram preenchidos com BHI. Amostras microbiológicas foram coletadas dos canais radiculares e contadas por meio de unidades formadoras de colônia em cada fase do tratamento utilizando-se ponta de papel dentro da luz do canal. Os dados foram analisados estatisticamente pelo teste de Kruskal-Wallis. As colônias bacterianas residuais foram então mensuradas. A utilização da clorexidina em gel a 2 por cento sem emprego da medicação intracanal reduziu em 100 por cento a contaminação por E. faecalis. O grupo que recebeu a medicação intracanal de hidróxido de cálcio por 14 dias permitiu o crescimento de pequeno número de bactérias entre as sessões, mas sem diferença estatística entre os grupos.

Biological response of pulps submitted to different capping materials / Resposta biológica de polpas submetidas a diferentes materiais capeadores

Pulp capping is a procedure that comprises adequate protection of the pulp tissue exposed to the oral environment, aiming at the preservation of its vitality and functions. This study evaluated the response of the dental pulps of dog teeth to capping with mineral trioxide aggregate (MTA) or calcium hydroxide P.A. For that purpose, 37 teeth were divided into two groups, according to the capping material employed. Two dogs were anesthetized and, after placement of a rubber dam, their pulps were exposed in a standardized manner and protected with the experimental capping materials. The cavities were then sealed with resin-modified glass ionomer cement and restored with composite resin. After sixty days, the animals were killed and the specimens were processed in order to be analyzed with optic microscopy. It was observed that MTA presented a higher success rate compared to calcium hydroxide, presenting a lower occurrence of infection and pulp necrosis.

O capeamento pulpar é um procedimento que consiste na adequada proteção do tecido pulpar exposto ao meio oral, objetivando a preservação de sua vitalidade e suas funções. O objetivo deste trabalho foi observar a resposta da polpa dental de cães ao capeamento com o agregado de trióxido mineral (MTA) ou hidróxido de cálcio P.A. Para tanto, 37 dentes foram divididos em dois grupos, de acordo com o material capeador utilizado. Dois cães foram anestesiados e após o isolamento absoluto do campo operatório, realizou-se exposição padronizada da polpa, proteção com os materiais capeadores testados e selamento das cavidades com cimento modificado de ionômero de vidro. Os dentes foram então restaurados com resina composta. Após sessenta dias, os animais foram sacrificados e as peças foram processadas para a análise microscópica dos dentes. Observou-se que o MTA apresentou maior índice de sucesso em relação ao hidróxido de cálcio, evidenciando menor ocorrência de infecção e necrose pulpar.

Histologic evaluation of pulpotomy performed with ethyl-cyanoacrylate and calcium hydroxide / Avaliação histológica de pulpotomia realizada com etil-cianoacrilato e com hidróxido de cálcio

The aim of this study was to evaluate histological aspects of the pulp-dentin complex of dogs submitted to pulpotomy and capped with ethyl-cyanoacrylate and calcium hydroxide. Thirty dog teeth were divided into 2 groups of 15 as follows: Group 1 - ethyl-cyanoacrylate; Group 2 - calcium hydroxide. The pulpotomies were carried out following all of the treatment precautions recommended for dogs. After 30 days the specimens were submitted to histological preparation and were then blindly evaluated by a histologist. Data were analyzed statistically by the Fisher exact test, comparing the two groups. After 30 days, the presence of a hard tissue barrier was observed in 83.3 percent of Group 1, and in 100 percent of Group 2 (p = 0.478). A continuous hard tissue barrier was observed in 50 percent of the ethyl-cyanoacrylate group and 75 percent of the calcium hydroxide group (p = 0.652). It can be concluded that both materials induced hard tissue barrier formation, but Group 2 had a higher percentage than Group 1, with no significant statistical differences; the differences observed between the different barriers (continuous/non-continuous) were not significant between groups and there was no pulpal necrosis in either group.

O objetivo do presente estudo foi avaliar o aspecto histológico do complexo dentino-pulpar de cachorros quando capeado após a pulpotomia com etil-cianoacrilato e hidróxido de cálcio. Trinta dentes de cães foram divididos em 2 grupos de 15 da seguinte forma: Grupo 1 - Etil-cianoacrilato; Grupo 2 - Hidróxido de cálcio. A pesquisa foi realizada tomando-se todos os cuidados recomendados para o tratamento com os cães. Após 30 dias do procedimento realizado os espécimes foram submetidos ao preparo histológico e logo após foram avaliados de forma cega por um histologista. Os resultados foram analisados estatisticamente através do Teste Exato de Fisher. No grupo 1, 83,3 por cento e no grupo 2, 100 por cento dos dentes apresentaram a barreira de tecido duro (p = 0,478). A barreira de tecido duro contínua foi observada em 50 por cento dos casos tratados com etil-cianoacrilato e em 75 por cento dos com hidróxido de cálcio (p = 0,652). Pode-se concluir que tanto o grupo 1 como o grupo 2 induziram a formação da barreira de tecido duro, porém o grupo 2 teve um percentual maior do que o grupo 1, não havendo diferença estatisticamente significante; a diferença observada entre as estruturas das barreiras (contínuas e não-contínuas) não foi significante. A necrose pulpar não foi observada em nenhum grupo.

Effect of rotary instrumentation and of the association of calcium hydroxide and chlorhexidine on the antisepsis of the root canal system in dogs

Este estudo objetivou avaliar a anti-sepsia do sistema de canais radiculares (SCR) e da região periapical (RP) proporcionada pela instrumentação automatizada associada a medicação intracanal à base de hidróxido de cálcio + clorexidina. Lesões periapicais crônicas foram induzidas em 26 raízes de pré-molares de dois cães. Após amostragem microbiológica, procedeu-se à instrumentação automatizada de 18 canais radiculares (CR) utilizando-se o sistema Profile e a solução de hipoclorito de sódio a 5,25%, com irrigação final com EDTA a 14,3%, seguida de irrigação profusa com soro fisiológico. Após se secarem os canais, foi colocada em seu interior uma pasta à base de hidróxido de cálcio P.A. associada à solução de digluconato de clorexidina a 2%. Transcorridos 21 dias, removeu-se a medicação, deixando-se os CR vazios e selados coronariamente. Após 96 horas, obteve-se a amostra microbiológica final e realizou-se o processamento histomicrobiológico pelo método de Brown & Brenn. Oito CR sem tratamento endodôntico representaram o grupo controle (G-C). Pelo teste de Mann-Whitney ao nível de 5% (p < 0,05), os procedimentos de anti-sepsia utilizados proporcionaram significativa eficácia (p < 0,05), resultando em 100,0% de CR livres de microrganismos. No G-C, verificou-se elevada incidência de vários morfotipos microbianos em todos os sítios do SCR e colônias microbianas na RP. Em contrapartida, no grupo experimental, verificou-se um padrão de infecção do SCR similar, mas menos intenso e reduzida presença de infecção extrarradicular (p < 0,05). Concluiu-se que a adequada instrumentação seguida da aplicação do hidróxido de cálcio + clorexidina proporcionou significativa eliminação de microrganismos.