Tissue response after subcutaneous implantation of different glass ionomer-based cements

Abstract The aim of this study was to evaluate the subcutaneous connective tissue response of isogenic mice after implantation of different glass ionomer-based cements (EQUIA® Forte Fil, EQUIA® Fil and Ketac™ Universal Aplicap™). Eighty-seven isogenic BALB/c mice were allocated in 12 groups, 9 were considered as experimental groups (Ketac, E. Fil and E. Forte at 7, 21 and 63 days) and 3 controls (empty polyethylene tubes at 7, 21 and 63 days). After the experimental periods, the subcutaneous connective tissue surrounding the implanted material was removed and subjected to histotechnical processing and staining with hematoxylin and eosin. A histopathological description of the tissue reaction surrounding each material and a semi-quantitative analysis of collagen fiber formation and inflammatory infiltrate were performed. Additionally, the thickness of the granulomatous tissue in contact with each material was measured. Data were analyzed statistically (α=0.05) by the Kruskal-Wallis test, followed by Dunn post-test. Initially, the collagen fiber formation was not different among all the tested materials (p>0.05) but was different at 21 days with the control group presenting the most advanced stage of collagen fiber formation. At 63 days, EQUIA® Forte Fil group showed the most advanced stage of collagen fiber formation, compared to EQUIA® Fil group (p<0.05). The inflammatory infiltrate was not different among the tested materials in any experimental period (p>0.05). The thickness of the granulomatous tissue was greater in the E. Forte group, compared to control in all periods. All glass ionomer-based cements showed tissue compatibility, according to the evaluated parameters.

Resumo O objetivo deste estudo foi avaliar a resposta subcutânea do tecido conjuntivo de camundongos isogênicos após o implante de diferentes cimentos à base de ionômero de vidro (EQUIA® Forte Fil, EQUIA® Fil e Ketac ™ Universal Aplicap ™). Oitenta e sete camundongos isogênicos BALB/c foram alocados em 12 grupos, 9 como grupos experimentais (Ketac, E. Fil e E. Forte aos 7, 21 e 63 dias) e 3 controles (tubos de polietileno vazios aos 7, 21 e 63 dias). Após os períodos experimentais, o tecido conjuntivo subcutâneo ao redor do material implantado foi removido e submetido ao processamento histotécnico e coloração com hematoxilina e eosina. Uma descrição histopatológica da reação tecidual envolvendo cada material e uma análise semi-quantitativa da fibrose e infiltrado inflamatório foram realizadas. Além disso, foi realizada a mensuração da espessura do tecido granulomatoso em contato com cada material. Os dados foram analisados estatisticamente (α=0,05) pelo teste de Kruskal-Wallis, seguido do pós-teste de Dunn. Inicialmente, a fibrose não foi diferente entre todos os materiais testados (p>0,05), mas foi diferente aos 21 dias, com o grupo controle apresentando o estágio mais avançado de fibrose. Aos 63 dias, o grupo EQUIA® Forte Fil apresentou o estágio mais avançado de fibrose, comparado ao grupo EQUIA® Fil (p<0,05). O infiltrado inflamatório não foi diferente entre os materiais testados em nenhum período experimental (p>0,05). A espessura do tecido granulomatoso foi maior no grupo E. Forte, comparado ao controle em todos os períodos. Todos os cimentos à base de ionômero de vidro apresentaram compatibilidade tecidual, de acordo com os parâmetros avaliados.

Carbon-Fiber Based Microelectrode Array Embedded with a Biodegradable Silk Support for In Vivo Neural Recording

BACKGROUND: Recently, carbon fibers have been utilized to develop a depth-type microelectrode array for chronic neural recording. Since the diameter of carbon fibers is smaller than the conventional electrodes made of metal wires or microfabricated silicon, the carbon fiber electrodes showed an improved capability for chronic neural recording with less tissue damages. However, the carbon fiber based microelectrodes have a limitation of short insertion depth due to a low stiffness. METHODS: We proposed a carbon fiber based microelectrode array embedded with a mechanical support structure to facilitate the penetration into the deeper brain. The support is made of biodegradable silk fibroin to reduce the reactive tissue responses. The 4-channel carbon fiber based microelectrode arrays were fabricated and accessed in terms of electrochemical impedance, recording capability for 1-month implantation in rat hippocampi. The electrodes with tungsten supports were fabricated and tested as a control group. Immunohistochemical analysis was performed to identify the reactive glial responses. RESULTS: The carbon fiber based electrode arrays with silk supports showed about 2-fold impedance increase 2 weeks after implantation while the number of active electrodes decreased simultaneously. However, after 1 month, the electrode impedance decreased back to its initial value and the percentage of active electrodes also increased above 70%. Immunohistochemical staining clearly showed that the electrodes with silk supports induced less reactive glial responses than that with tungsten supports. CONCLUSION: The proposed carbon fiber based microelectrode array is expected to be used for long-term in vivo neural recording from deep brain regions with the minimized reactive tissue response.

Comparative Histologic Study of 3-Root Canal Filling Materials for Dog's Teeth / 대한소아치과학회지

Endodontic treatment of primary molars is a great challenge to the dentists because of their complex morphology. However, there have been limited controlled in vivo studies about filling materials for primary teeth. Hence, the aim of this study is to evaluate and compare histologic responses of different calcium hydroxide canal filling materials that are used in daily clinical practice.Pulpectomies were performed in 132 teeth of the dogs. The root canals were randomly filled with either Vitapex® (n = 44), Metapex® (n = 44), or Metapaste® (n = 44). After 4 or 13 weeks, respectively after operation, the dogs were sacrificed, and teeth were processed for histologic examinations. Inflammatory reaction was evaluated and scored in a blind manner. The Fisher's exact test and Kruskal-Wallis test were used to compare the tested groups.In 4-week-group, all inflammatory responses were in normal range except for fibrosis. In 13-week-group, increased response to various inflammation reaction was shown compared to the 4-week-group. However, there were no statically significant differences between the tested groups in all inflammatory reaction.Overall, there were no significant differences among three materials in responses of apical tissues and all of them showed favorable tissue responses.

Biocompatibility of a New Dental Glass Ionomer Cement with Cellulose Microfibers and Cellulose Nanocrystals

Resumo Os novos materiais restauradores em desenvolvimento devem evitar danos aos tecidos dentários. Portanto, o objetivo deste estudo foi avaliar a biocompatibilidade de uma marca comercial de cimento de ionômero de vidro convencional (CIV) modificado com microfibras de celulose (CIV+MC) ou nanocristais de celulose (CIV+NC) através da implantação de três amostras em tecido subcutâneo na região dorsal de 15 ratos Rattus norvegicus albinus. Cada rato recebeu um exemplar de cada cimento, resultando nos seguintes grupos (n=15): Grupo CIV (controle, n=15), Grupo CIV+MC e Grupo CIV+NC. Nos intervalos de 7, 30 e 60 dias os animais foram sacrificados e os seguintes aspectos foram avaliados histologicamente: tipo de células inflamatórias, fibroblastos, vasos sanguíneos, macrófagos, células gigantes, tipo de reação inflamatória e espessura da cápsula (µm). Estes eventos foram quantitativamente classificados conforme os escores: (-) ausente, (+) suave, (++) moderado e (+++) intenso. Os resultados foram analisados estatisticamente pelo teste Kruskal-Wallis e pós-teste Mann-Whitney. Aos 7 dias, o Grupo CIV+NC demonstrou um nível mais elevado de reparação tecidual porque havia maior quantidade de fibroblastos (p=0,022) e uma menor quantidade de macrófagos (p=0,008) e células mononucleares (p=0,033). Neutrófilos e células gigantes estavam ausentes em todos os períodos experimentais. Aos 60 dias, o Grupo CIV+NC apresentou cápsula de tecido fibroso com espessura mais reduzida (26,72±2,87 µm) em comparação ao Grupo CIV+MC (41,21±3,98 µm (p=0,025). No geral, todos os materiais apresentaram satisfatória biocompatibilidade, no entanto, o cimento de ionômero de vidro modificado com nanocristais de celulose proveu reparação tecidual mais avançada comparativamente aos demais materiais avaliados.

Developing new restorative materials should avoid damage to tissue structures. This study evaluated the biocompatibility of a commercial dental glass ionomer cement (GIC) mechanically reinforced with cellulose microfibers (GIC+CM) or cellulose nanocrystals (GIC+CN) by implantation of three test specimens in subcutaneous tissue in the dorsal region of 15 Rattus norvegicus albinus rats. Each rat received one specimen of each cement, resulting in the following groups (n=15): Group GIC (Control), Group GIC+CM and Group GIC+NC. After time intervals of 7, 30 and 60 days, the animals were sacrificed and the following aspects were histologically evaluated: type of inflammatory cells, fibroblasts, blood vessels, macrophages, giant cells, type of inflammatory reaction and capsule thickness (µm). These events were scored as (-) absent, (+) light, (++) moderate and (+++) intense. The results were statistically analyzed by Kruskal-Wallis test and Mann-Whitney post test. At 7 days, Group GIC+NC showed more favorable tissue repair because quantitatively there were more fibroblasts (p=0.022), fewer macrophages (p=0.008) and mononuclear cells (p=0.033). Polymorphonuclear neutrophils and giant cells were absent in all experimental periods. At 60 days, test specimens in Group GIC+NC were surrounded by a fibrous tissue capsule with reduced thickness (26.72±2.87 µm) in comparison with Group GIC+CM (41.21±3.98 µm) (p=0.025). In general, all biomaterials showed satisfactory biocompatibility, but glass ionomer cement modified with cellulose nanocrystals showed a more advanced tissue repair.

Microscopical and chemical surface characterization of CAD/CAM zircona abutments after different cleaning procedures. A qualitative analysis

PURPOSE: To describe and characterize the surface topography and cleanliness of CAD/CAM manufactured zirconia abutments after steaming and ultrasonic cleaning. MATERIALS AND METHODS: A total of 12 ceramic CAD/CAM implant abutments of various manufacturers were produced and randomly divided into two groups of six samples each (control and test group). Four two-piece hybrid abutments and two one-piece abutments made of zirconium-dioxide were assessed per each group. In the control group, cleaning by steam was performed. The test group underwent an ultrasonic cleaning procedure with acetone, ethyl alcohol and antibacterial solution. Groups were subjected to scanning electron microscope (SEM) analysis and Energy-dispersive X-ray spectroscopy (EDX) to verify and characterize contaminant chemical characterization non-quantitatively. RESULTS: All zirconia CAD/CAM abutments in the present study displayed production-induced wear particles, debris as well as organic and inorganic contaminants. The abutments of the test group showed reduction of surface contamination after undergoing an ultrasonic cleaning procedure. However, an absolute removal of pollutants could not be achieved. CONCLUSION: The presence of debris on the transmucosal surface of CAD/CAM zirconia abutments of various manufacturers was confirmed. Within the limits of the study design, the results suggest that a defined ultrasonic cleaning process can be advantageously employed to reduce such debris, thus, supposedly enhancing soft tissue healing. Although the adverse long-term influence of abutment contamination on the biological stability of peri-implant tissues has been evidenced, a standardized and validated polishing and cleaning protocol still has to be implemented.

Microscopical and chemical surface characterization of CAD/CAM zircona abutments after different cleaning procedures. A qualitative analysis

PURPOSE: To describe and characterize the surface topography and cleanliness of CAD/CAM manufactured zirconia abutments after steaming and ultrasonic cleaning. MATERIALS AND METHODS: A total of 12 ceramic CAD/CAM implant abutments of various manufacturers were produced and randomly divided into two groups of six samples each (control and test group). Four two-piece hybrid abutments and two one-piece abutments made of zirconium-dioxide were assessed per each group. In the control group, cleaning by steam was performed. The test group underwent an ultrasonic cleaning procedure with acetone, ethyl alcohol and antibacterial solution. Groups were subjected to scanning electron microscope (SEM) analysis and Energy-dispersive X-ray spectroscopy (EDX) to verify and characterize contaminant chemical characterization non-quantitatively. RESULTS: All zirconia CAD/CAM abutments in the present study displayed production-induced wear particles, debris as well as organic and inorganic contaminants. The abutments of the test group showed reduction of surface contamination after undergoing an ultrasonic cleaning procedure. However, an absolute removal of pollutants could not be achieved. CONCLUSION: The presence of debris on the transmucosal surface of CAD/CAM zirconia abutments of various manufacturers was confirmed. Within the limits of the study design, the results suggest that a defined ultrasonic cleaning process can be advantageously employed to reduce such debris, thus, supposedly enhancing soft tissue healing. Although the adverse long-term influence of abutment contamination on the biological stability of peri-implant tissues has been evidenced, a standardized and validated polishing and cleaning protocol still has to be implemented.

In vivo evaluation of tissue response to new endodontic sealers

Introduction: The sealers can be in direct contact with the periapical tissues. Thus, these materials must have appropriate physical and biological properties, providing conditions for repair to occur. Objective: The aim of this study was to evaluate the response of rat subcutaneous tissue to endodontics sealers. Material and methods: Three materials comprised the groups: group I - Zinc Oxide, Eugenol and Iodoform paste, group II - Portland cement with propylene glycol, and group III - MTA Fillapex® (Angelus). These materials were placed in polyethylene tubes and implanted into dorsal connective tissue of Wistar rats for seven and 15 days. The specimens were stained with hematoxylin and eosin and evaluated regarding to inflammatory reaction parameters through a light microscope. The data were compared using Kruskal-Wallis test with significance level of 5%. The intensity of inflammatory response against the sealers was analyzed by two blinded and previously calibrated observers for all experimental periods. Results: The histological evaluation showed that all the materials caused a moderated inflammatory reaction at seven days which decreased with time. A greater inflammatory reaction was observed at seven days in group I. The other specimens had significantly less inflammatory cells when compared to this group. Tubes with MTA Fillapex® presented some giant cells, macrophages and lymphocytes after seven days. At 15 days, the presence of fibroblasts and collagen fibers was observed indicating normal tissue healing. The group II showed similar results to those observed in MTA Fillapex® already at seven days. At 15 days the inflammatory reaction presented was almost absent at the tissue, with many collagen fibers indicating normal tissue healing. Statistical analysis showed a significant statistical difference amongst the group I (seven days) and II (15 days) (p < 0.05). In the other groups no significant statistical differences were observed. Conclusion: MTA Fillapex® and Portland cement with propylene glycol were more biocompatible than the other tested cements.

Foreign body penetration: a missed diagnosis

Healing of the injured site is a complex biological process of carefully orchestrated cellular events. Presence of any foreign body at the site of injury delays the healing along with inducing biological response such as inflammation, infections, allergic reactions, toxic events and tissue alterations. Such body reactions against an exogenous materials depends upon the mode of entry, chemical composition of material, quantity of material its physical form and also depends upon the body site. A careful history, clinical examination and imaging techniques should be considered for patients with any suspected penetrating injuries.

Subcutaneous connective tissue response to primary root canal filling materials

This study evaluated the response of the subcutaneous connective tissue of BALB/c mice to root filling materials indicated for primary teeth: zinc oxide/eugenol cement (ZOE), Calen paste thickened with zinc oxide (Calen/ZO) and Sealapex sealer. The mice (n=102) received polyethylene tube implants with the materials, thereby forming 11 groups, as follows: I, II, III: Calen/ZO for 7, 21 and 63 days, respectively; IV, V, VI: Sealapex for 7, 21 and 63 days, respectively; VII, VIII, IX: ZOE for 7, 21 and 63 days, respectively; X and XI: empty tube for 7 and 21 days, respectively. The biopsied tissues were submitted to histological analysis (descriptive analysis and semi-quantitative analysis using a scoring system for collagen fiber formation, tissue thickness and inflammatory infiltrate). A quantitative analysis was performed by measuring the area and thickness of the granulomatous reactionary tissue (GRT). Data were analyzed by Kruskal-Wallis, ANOVA and Tukey's post-hoc tests (?=0.05). There was no significant difference (p>0.05) among the materials with respect to collagen fiber formation or GRT thickness. However, Calen/ZO produced the least severe inflammatory infiltrate (p<0.05). The area of the GRT was significantly smaller (p<0.05) for Calen/ZO and Sealapex. In conclusion, Calen/ZO presented the best tissue reaction, followed by Sealapex and ZOE.

Neste estudo avaliou-se a resposta do tecido conjuntivo subcutâneo de camundongos BALB/c a materiais obturadores de canal radicular de dentes decíduos: óxido de zinco/eugenol (OZE), pasta Calen® espessada com óxido de zinco (Calen/OZ) e cimento Sealapex®. Os camundongos (n=102) receberam implantes de tubos de polietileno??? e foram divididos em grupos: I, II, III - Calen/OZ (7, 21 e 63 dias, respectivamente); IV, V, VI - Sealapex (7, 21 e 63 dias, respectivamente); VII, VIII, IX - OZE (7, 21 e 63 dias, respectivamente); X, XI - tubo vazio (7 e 21 dias, respectivamente). Os tecidos foram submetidos ao processamento e análise histopatológica descritiva e por meio de escores do fibrosamento, espessura tecidual e infiltrado inflamatório. Para a análise quantitativa mensurou-se a área e a espessura do tecido granulomatoso reacional (TGR). Os resultados foram analisados pelos testes de Kruskal-Wallis, ANOVA e pós-teste de Tukey (?=0,05). Não houve diferença significante (p>0,05) entre os materiais, com relação ao fibrosamento e à espessura do TGR. Contudo, Calen/OZ apresentou infiltrado inflamatório de menor intensidade (p<0,05). A área do TGR foi menor (p<0,05) para Calen/OZ e Sealapex. Pôde-se concluir que Calen/OZ foi o material que apresentou a melhor compatibilidade tecidual, seguido pelos cimentos Sealapex e OZE.

Subcutaneous tissue response of isogenic mice to calcium hydroxide-based pastes with chlorhexidine

This study was evaluated the response of subcutaneous connective tissue of isogenic mice to calcium hydroxide-based pastes with chlorhexidine digluconate (CHX). Seventy isogenic male BALB/c mice aged 6-8 weeks and weighing 15-20 g were randomly assigned to 8 groups. The animals received polyethylene tube implants as follows: Groups I, II, and III (n=10) - Calen® paste mixed with 0.4 percent CHX (experimental paste; Calen/CHX) for 7, 21, and 63 days, respectively; Groups IV, V, and VI (n=10) - UltraCal™ paste mixed with 2 percent CHX (experimental paste supplied by Ultradent Products Inc.; Ultracal/CHX) for 7, 21, and 63 days, respectively; and Groups VII and VIII (n=5): empty tube for 7 and 21 days, respectively. At the end of the experimental periods, the implants were removed together with the surrounding tissues (skin and subcutaneous connective tissue). The biopsied tissues were subjected to routine processing for histological analysis. Using a descriptive analysis and a four-point (0-3) scoring system, the following criteria were considered for qualitative and quantitative analysis of the tissue around the implanted materials: collagen fiber formation, tissue thickness and inflammatory infiltrate. A quantitative analysis was performed by measuring the thickness (µm), area (µm²) and perimeter (µm) of the reactionary granulomatous tissue formed at the tube ends. Data were analyzed statistically by the Kruskal-Wallis test and Dunn's post-test (á=0.05). Calen/CHX showed biocompatibility with the subcutaneous and reactionary tissues, with areas of discrete fibrosis and normal conjunctive fibrous tissue, though without statistically significant difference (p>0.05) from the control groups. In Groups I to III, there was a predominance of score 1, while in Groups IV to VI scores 2 and 3 predominated for all analyzed parameters. UltraCal/CHX, on the other hand, induced the formation of an inflammatory infiltrate and abundant exudate, ...

O objetivo do presente estudo foi avaliar a resposta do tecido conjuntivo subcutâneo de camundongos isogênicos frente a pastas à base de hidróxido de cálcio, associadas ao digluconato de clorexidina (CHX). Setenta camundongos isogênicos BALB/c machos, com 6-8 semanas e pesando 15-20 g foram aleatoriamente divididos em 8 grupos. Os animais receberam implantes de tubos de polietileno contendo: Grupos I, II e III (n=10) - pasta Calen® associada à CHX a 0,4 por cento (Calen/CHX), por 7, 21 e 63 dias, respectivamente; Grupos IV, V e VI (n=10) - pasta UltraCal™ associada à CHX a 2 por cento (pasta experimental fornecida pela Ultradent Products Inc.; Ultracal/CHX), por 7, 21 e 63 dias, respectivamente; e Grupos VII e VIII (n=5) - tubo de polietileno vazio, por 7 e 21 dias, respectivamente. Decorridos os períodos experimentais, os implantes foram removidos juntamente com os tecidos circundantes (pele e tecido conjuntivo). Os tecidos foram submetidos ao processamento histotécnico de rotina, para análise histopatológica. Empregando um sistema de escores, os seguintes critérios foram considerados para a análise qualitativa e quantitativa: fibrosamento, espessura tecidual e infiltrado inflamatório. Foi efetuada, também, a análise quantitativa da medida da espessura (µm), área (µm²) e perímetro (µm) do tecido granulomatoso reacional formado na abertura dos tubos. Os dados obtidos foram submetidos à análise estatística, empregando o teste de Kruskal-Wallis e o pós-teste de Dunn. O nível de significância adotado foi de 5 por cento. Os resultados demonstraram biocompatibilidade da pasta Calen associada à CHX a 0,4 por cento com o tecido adjacente, com fibrosamento discreto, assim como tecido conjuntivo normal, sem diferença estatística significante com os controles (p>0,05). Nos Grupos I, II e III houve predominância do escore 1, enquanto que nos Grupos IV, V e VI houve predominância dos escores 2 e 3, em todos os parâmetros analisados. Em relação ...

Comparative study on tissue responses of 3 resorbable membranes in rats / 대한치주과학회지

The purpose of this study is to evaluate histologically the resorption and tissue response of various resorbable collagen membranes used for guided tissue regeneration and guided bone regeneration, using a subcutaneous model on the dorsal surface of the rat. In this study, 10 Sprague-Dawley male rats (mean BW 150gm) were used and the commercially available materials included acellular dermal matrix allograft, porcine collagen membrane, freeze-dried bovine dura mater. Animals were sacrificed at 2, 6 and 8 weeks after implantation of various resorbable collagen membranes. Specimens were prepared with Hematoxylin-Eosin stain for light microscopic evaluation. The results of this study were as follows: 1. Resorption : Inner portion of porcine collagen membrane was resorbed a lot at 6 weeks, but its function was being kept for infiltration of another tissues were not observed. Freeze-dried bovine dura mater and acellular dermal allograft were rarely resorbed and kept their structure of outer portion for 8 weeks. 2. Inflammatory reactions : Inflammatory reaction was so mild and foreign body reaction didn't happen in all of resorbable collagen membranes, which showed their biocompatibility. 3. In all of resorbable collagen membranes, multinucleated giant cells by foreign body reactions were not observed. Barrier membranes have to maintain their function for 4-6 weeks in guided tissue regeneration and at least 8 weeks in guided bone regeneration. According to present study, we can find all of the resorbable collagen membranes kept their function and structure for 8 weeks and were rarely resorbed. Foreign body reaction didn't happen and inflammatory reaction was so mild histologically. Therefore, all of collagen membranes used in this experiment were considered proper resorbable membranes for guided tissue regeneration and guided bone regeneration.

The thickness of soft-tissue based on body mass index and postoperative change in prognathic patients