Calcium aluminate cement: Used in bone defects induced in the femur of rabbits

The patterns of the calcium aluminate cement in bone defects experimentally induced in the femur of 12 New Zealand White rabbits were evaluated. The animals were distributed in three experimental groups, corresponding to postoperative observation periods of 15 (G15), 30 (G30) and 60 (G60) days. Clinical, surgical, radiographic and histological appraisals were made to observe the osteoinductor and osteoconductor potential of the biological material, as well as the bone integration. The calcium aluminate cement formulation was biocompatible, but has not acted as a osteoconductor or osteoinductor.

Biocompatibility of New Calcium Aluminate Cement: Tissue Reaction and Expression of Inflammatory Mediators and Cytokines

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Repair of Bone Defects Filled with New Calcium Aluminate Cement (EndoBinder)

The aim of this study was to evaluate and compare the repair of bone defects filled with calcium aluminate cement (EndoBinder), mineral trioxide aggregate (MTA), and calcium hydroxide. Methods After mixing, the cements were inserted into bone defects (3.3 mm) mechanically created in the right and left tibias of 30 rats (Rattus norvegicus, Wistar). In the control group, the bone defects were filled with blood clot of the animal itself. After time intervals of 7, 30, and 90 days had elapsed, bone tissue biopsies (n = 5) were surgically obtained and submitted to laboratory processing. The response of bone tissue in contact with the materials was microscopically analyzed. The percentage of neoformed bone tissue in the defect was determined by means of planimetry counting points superimposed on the histologic image. Results Significant increase in the percentage of neoformed bone tissue was observed throughout the experimental periods in all groups (P < .05). For the cements EndoBinder and MTA (30 and 90 days), these percentage values were statistically higher than those of the control group (P < .05); however, they were similar to those of calcium hydroxide (P > .05). Conclusions EndoBinder and MTA allowed complete repair of bone defects created in rat tibias.

Osteoconductive Properties of beta-Tricalcium Phosphate Matrix, Polylactic and Polyglycolic Acid Gel, and Calcium Phosphate Cement in Bone Defects

Extensive bone defects in maxillofacial region can be corrected with autogenous grafts; otherwise, the disadvantages of the therapeutics modality take the research for new bone substitutes. The aim of the study was to evaluate and compare the osteoconductive properties of 3 commercial available biomaterials. A total of 30 calvarial defects (5-mm diameter) were randomly divided into 5 treatment groups, with a total of 6 defects per treatment group (n = 6). The treatment groups were as follows: 500 to 1000 Km beta-tricalcium phosphate (beta-TCP), polylactic and polyglycolic acid (PL/PG) gel, calcium phosphate cement, untreated control, and autograft control. The evaluations were based on histomorphometric analysis at 60 postoperative days. The results have shown that beta-TCP and autograft control supported bone formation at 60 postoperative days. beta-Tricalcium phosphate showed the highest amount of mineralized area per total area and statistically significant compared with PL/PG, calcium phosphate cement, and untreated control groups. The PL/PG gel does not have osteoconductive properties and performed similar to empty control. Calcium phosphate cement showed higher number of multinucleated giant cells around the sites of the biomaterial and showed newly formed bone only at the edges of the biomaterial, without bone formation within the biomaterial. The findings presented herein indicate that bone formation reached a maximum level when rat calvarial defects were filled with beta-TCP at 60 postoperative days. Further studies should be conducted with beta-TCP to understand the potential of this biomaterial in bone regeneration.

Evaluation of mineral trioxide aggregate and calcium hydroxide cement as pulp-capping agents in human teeth

This study evaluated the histomorphologic response of human dental pulps capped with mineral trioxide aggregate (MTA) and Ca(OH)(2) cement (CH). Pulp exposures were performed on the occlusal floor of 40 human permanent premolars. After that, the pulp was capped either with CH or MTA and restored with composite resin. After 30 and 60 days, teeth were extracted and processed for histologic exam and categorized in a histologic score system. The data were subjected to Kruskal-Wallis and Conover tests (alpha = .05). All groups performed well in terms of hard tissue bridge formation, inflammatory response, and other pulpal findings. However, a lower response of CH30 was observed for the dentin bridge formation, when compared with MTA30 and MTA60 groups. Although the pulp healing with calcium hydroxide was slower than that of MTA, both materials were successful for pulp capping in human teeth.

Utilization of autogenous bone, bioactive glasses, and calcium phosphate cement in surgical mandibular bone defects in Cebus apella monkeys

Purpose: the purpose of the present study was to evaluate the histologic results of bone cavities that were surgically created in the mandibles of Cebus apella monkeys and filled with autogenous bone, PerioGlas, FillerBone, or Bone Source. Materials and Methods: Surgical cavities 5 mm in diameter were prepared through both mandibular cortices in the mandibular angle region. The cavities were randomly filled, and the animals were divided into groups according to the material employed: Group 1 cavities were filled with autogenous corticocancellous bone; group 2 cavities were filled with calcium phosphate cement (BoneSource); and group 3 and group 4 cavities were filled with bioactive glass (FillerBone and PerioGlas, respectively). After 180 days the animals were sacrificed, and specimens were prepared following routine laboratory procedures for hematoxylin/eosin staining and histologic evaluation. Results: the histologic analysis showed that autogenous bone allowed total repair of the bone defects; bioactive glasses (FillerBone and PerioGlas) allowed total repair of the defects with intimate contact of the remaining granules and newly formed bone; and the cavities filled with calcium phosphate cement (BoneSource) were generally filled by connective fibrous tissue, and the material was almost totally resorbed. Discussion: the autogenous bone, FillerBone, and PerioGlas provided results similar to those in the current literature, showing that autogenous bone is the best Choice for filling critical-size defects. Synthetic implanted materials demonstrated biocompatibility, but the bioglasses demonstrated osteoconductive activity that did not occur with calcium phosphate (BoneSource). Conclusion: According to the methodology used in this study, it can be concluded that the utilization of autogenous bone and bioactive glasses permitted the repair of surgically created critical-size defects by newly formed bone; the synthetic implanted materials demonstrated biocompatibility, and the bioactive glasses demonstrated osteoconductive activity. The PerioGlas was mostly resorbed and replaced by bone and the remaining granules were in close contact with bone; the FillerBone showed many granules in contact with the newly formed bone; BoneSource did not permit repair of the critical-size defects, and the defects were generally filled by connective fibrous tissue.

Response of the pulp of dogs to capping with mineral trioxide aggregate or a calcium hydroxide cement

This study was conducted to observe the response of dogs' dental pulp to mineral trioxide aggregate (MTA) and a calcium hydroxide cement when used as pulp capping materials. After the pulps of 30 teeth were exposed, they were capped with either MTA or a calcium hydroxide cement. Histological analysis was performed 2 months after treatment. Results showed a healing process with complete tubular dentin bridge formation and no inflammation in any of the pulps capped with MTA. on the other hand, only five specimens from the calcium hydroxide cement group formed a complete dentin bridge. In this experimental group, pulp inflammation was observed in all but three cases. In conclusion, MTA exhibited better results than the calcium hydroxide cement for the capping of the pulp in dogs.

Microparticulated and nanoparticulated zirconium oxide added to calcium silicate cement: Evaluation of physicochemical and biological properties

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The association of chlorhexidine digluconate and calcium chloride to use as vehicle of a silicate calcium-based cement

Objective: The purpose of this study was to evaluate the influence of the addition of 2% chlorhexidine digluconate (CHX) associated with 5% calcium chloride (CaCl2 ) on antimicrobial activity, setting time, pH and calcium release of gray mineral trioxide aggregate (GMTA). Materials and Methods: GMTA powder was mixed with water, 2% CHX alone or 2% CHX combined with 5% CaCl2 . Antimicrobial activity was determined against Enterococcus faecalis (ATCC 29212) strains by agar diffusion test. Data obtained were submitted to kruskal wallis tests. Analysis of the setting time was evaluated by American society for testing and materials C266-03 requirements. The pH and calcium release analysis were evaluated, in 24 h, 7, 14 and 28 days using pH meter equipment and atomic absorption spectrophotometer, respectively. Data obtained were analyzed by ANOVA, in 5% significance level. Results: Significant differences were seen (P < 0.01) among the zones of bacterial growth inhibition produced by 5% CaCl2 + 2% CHX combination against E. faecalis when compared with water (P < 0.05). Regarding the setting time, that combination had the shortest setting time (P < 0.05). All associations were alkaline and released calcium. No statistical difference was observed between the experimental groups at the different periods of analysis (P > 0.05). Conclusion: Combination of 5% CaCl2 + 2% CHX reduced the setting time and enhanced the antimicrobial activity of GMTA without changing the pH and calcium release.

Cimento de Aluminato de Cálcio – Uso em defeitos ósseos induzidos em fêmures de coelhos (Oryctolagus cuniculus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Short-term evaluation of the pulpo-dentin complex response to a resin-modified glass-ionomer cement and a bonding agent applied in deep cavities

Objectives. To evaluate the response of the pulpo-dentin complex following application of a resin-modified glass-ionomer cement or an adhesive system in deep cavities performed in human teeth.Methods. Deep class V cavities were prepared on the buccal surface of 26 premolars. In Group I the cavity walls (dentin) and enamel were conditioned with 32% phosphoric acid and the dentin adhesive system One Step (Bisco, Inc., Itasca, IL, USA) was applied. In Groups 2 and 3, before total etching and application of bonding agent, the cavity floor was lined with the resin-modified glass-ionomer cement-Vitrebond (3M ESPE Dental Products Division, St. Paul, MN, USA) or the calcium hydroxide cement-Dycal (control group, Dentsply, Mildford, DE, USA), respectively. The cavities were restored using light-cured Z-100 composite resin (3M ESPE). The teeth were extracted between 5 and 30 days and prepared for microscopic assessment. Serial sections were stained with H/E, Masson's trichrome, and Brown and Brenn techniques.Results. In Group 1, the inflammatory response was more evident than in Groups 2 and 3. Diffusion of dental material components across dentinal tubules was observed only in Group 1, in which the intensity of the pulp response increased as the remaining dentin thickness decreased. Bacteria were evidenced in the lateral walls of two samples (Group 2) which exhibited no inflammatory response or tissue disorganization.Conclusions. Based on the experimental conditions, it was concluded total acid etching followed by application of One Step bonding agent cannot be recommended as adequate procedures. In this clinical condition the cavity walls should be lined with a biocompatible dental material, such as Vitrebond or Dycal. 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Subcutaneous tissue reaction to castor oil bean and calcium hydroxide in rats

Castor oil bean cement (COB) is a new material that has been used as an endodontic sealer, and is a candidate material for direct pulp capping. Objective: The purpose of this study was to evaluate the biocompatibility of a new formulation of COB compared to calcium hydroxide cement (CH) and a control group without any material, in the subcutaneous tissue of rats. Material and Methods: The materials were prepared, packed into polyethylene tubes, and implanted in the rat dorsal subcutaneous tissue. Animals were sacrificed at the 7th and 50th days after implantation. A quantitative analysis of inflammatory cells was performed and data were subjected to ANOVA and Tukey's tests at 5% significance level. Results: Comparing the mean number of inflammatory cells between the two experimental groups (COB and CH) and the control group, statistically significant difference (p=0.0001) was observed at 7 and 50 days. There were no significant differences (p=0.111) between tissue reaction to CH (382 inflammatory cells) and COB (330 inflammatory cells) after 7 days. After 50 days, significantly more inflammatory cells (p=0.02) were observed in the CH group (404 inflammatory cells) than in the COB group (177 inflammatory cells). Conclusions: These results demonstrate that the COB cement induces less inflammatory response within long periods.

Response of human dental pulp capped with MTA and calcium hydroxide powder

Objectives: To compare the response of human dental pulp capped with a mineral trioxide aggregate (MTA) and Ca(OH) 2 powder. Methods and Material: Pulp exposures were performed on the occlusal floor of 40 permanent premolars. The pulp was then capped with either Ca(OH) 2 powder (CH) or MTA and restored with resin composite. After 30 days (groups CH30 and MTA30) and 60 days (groups CH60 and MTA60), the teeth were extracted and processed for HE and categorized in a histological score system. The data were subjected to Kruskal-Wallis and Conover tests (α=0.05). Results: In regard to dentin bridge formation, CH30 showed a tendency towards superior performance compared to MTA30 (p>0.05), although the products showed comparable results at day 60. In the item Inflammation and General State of the Pulp (p>0.05), CH showed a tendency towards presenting a higher inflammatory response. In the item Other Pulpal Findings, MTA and Ca(OH) 2 showed equal and excellent performance after 30 and 60 days (p>0.05). Conclusion: After 30 days, Ca(OH) 2 powder covered with calcium hydroxide cement showed faster hard tissue bridge formation compared to MTA. After 60 days, Ca(OH) 2 powder or MTA materials showed a similar and excellent histological response with the formation of a hard tissue bridge in almost all cases with low inflammatory infiltrate. © Operative Dentistry, 2008.

Cimentos bioativos injetáveis funcionalizados com peptídeo osteogênico para reparação óssea

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biocompatibilidade do cimento de fosfato de cálcio implantado no rádio de coelhos

OBJETIVO: Avaliar a biocompatibilidade do cimento de fosfato de cálcio, para verificar sua eficácia como possível substituto ósseo. MÉTODOS: No presente trabalho, foi utilizado cimento de fosfato de cálcio em rádio de 8 coelhos, separados em dois grupos (GI e GII), referentes aos tempos de observação de 12 e 26 semanas pós-operatórias, a fim de se observar as reações entre este biomaterial e o tecido ósseo do animal. Foram feitas análises radiográficas e de densitometria óptica, além de microscopia óptica e eletrônica de varredura. RESULTADOS: Observou-se, ao final do experimento, que o cimento à base de fosfato de cálcio foi parcialmente reabsorvido durante o tempo de observação de 26 semanas, apresentando biocompatibilidade, com ausência de reações indesejáveis que pudessem ser atribuídas aos implantes. CONCLUSÕES: O cimento à base de fosfato de cálcio foi biocompatível e parcialmente reabsorvido no período de 26 semanas de observação. Tempos maiores de observação são necessários para a avaliação da reabsorção.