Rat tissue reaction and cytokine production induced by antimicrobial photodynamic therapy.

BACKGROUND: The antimicrobial photodynamic therapy (aPDT) inactivates the target cell via reactions among the photosensitizer (PS), Laser or Led and O2. The aim of this study was to evaluate the tissue reaction and cytokine production promoted by aPDT with curcumin photosensitizer. METHODS: Polyethylene tubes containing saline solution (control), 5% sodium hypochlorite (NaOCl) and aPDT with curcumin PS 500mg/L, were implanted into dorsal connective tissue of Wistar rats. After 7, 15, 30, 60 and 90days of implantation, the animals were euthanized and the tubes with surrounding tissues were removed. The specimens were divided in two part, one half was processed, fixed and prepared for histological analysis by staining with hematoxylin and eosin. The other half was collected for IL-1ß and IL-6 cytokine production using ELISA assay. The results were statistically analyzed by Kruskal-Wallis test followed by Dunn test (p<0.05) for tissue reaction and ANOVA followed by Bonferroni's correction (p<0.05) for ELISA. RESULTS: All groups showed severe tissue reactions at 7days, whilst a significantly decrease by time was observed. Regarding to cytokine production, aPDT increases the IL-1ß levels in all periods of time (p<0.05). However, for IL-6 levels, the highest value was observed with aPDT on the 90th day (p<0.05). CONCLUSIONS: aPDT with curcumin PS 500mg/L demonstrated biocompatibility similar to saline solution and induced the IL-1ß and IL-6 cytokines production.

Effect of raloxifene on periapical lesions in ovariectomized rats.

INTRODUCTION: The aim of this study was to evaluate the effect of raloxifene (RLX) during progression of periapical lesions in ovariectomized (OVX) rats. METHODS: Female Wistar rats were OVX or subjected to sham surgery and received vehicle or RLX by gavage for 90 days. The treatment groups were as follows: sham surgery and treated with vehicle (SHAM-veh), OVX and treated with vehicle (OVX-veh), and OVX and treated with RLX (OVX-RLX). During treatment, the pulp of lower first molar was exposed to the oral environment for induction of periapical lesion that was analyzed 7 or 30 days after procedure. Blood samples were taken from jugular vein for measurement of estradiol, and the mandibles were removed and prepared for radiographic, histopathologic, histometric, and immunohistochemical analysis. RESULTS: Estradiol plasma concentration showed hypoestrogenism in OVX rats. The histopathologic analysis of the OVX/RLX group was similar to that of the SHAM-veh group, whereas OVX-veh group showed larger periapical lesions with more intense inflammatory response and more cells positive for tartrate-resistant acid phosphatase. Radiographically, the groups were similar, but lesions on day 7 were smaller than lesions on day 30. CONCLUSIONS: The results suggest that hypoestrogenism potentiates the progression of periapical lesions, and such condition was reversed by treatment with RLX.

Histologic characterization of engineered tissues in the canal space of closed-apex teeth with apical periodontitis.

INTRODUCTION: The aim of this study was to investigate the capacity of endodontic regenerative procedures combining an induced blood clot, platelet-rich plasma (PRP), and bone marrow aspirate (BMA) to regenerate dental pulp in canine closed-apex necrotic teeth. METHODS: Apical periodontitis was induced in 20 upper and lower premolars of 2 dogs. After biomechanical preparation, enlargement to a #60 file, and disinfection with a triantibiotic paste for 28 days, the roots were randomly assigned to 4 treatment groups: blood clot (BC), BC + PRP gel, BC + BMA gel, and BC + BMA/PRP gel. Negative controls were also included. After a 3-month follow-up period, the animals were killed. RESULTS: Histologic analysis showed the presence of newly formed vital tissues (connective, cement-like, and bone-like tissue) in 23 of the 32 treated roots (71.87%). There was no statistically significant difference between the treatment groups. CONCLUSIONS: New vital tissues were formed and characterized as connective, cementum-like, or bone-like, but not as pulp-like tissue; PRP and/or BMA did not improve the tissue ingrowth.

Avaliação histológica de estratégias de engenharia tecidual para a terapia endodôntica / Histological evaluation of tissue engineering strategies for endodontic therapy

O objetivo deste estudo foi avaliar a resposta tecidual ao implante de tubos de polietileno preenchidos com pasta triantibiótica (PTA) composta de ciprofloxacina, minociclina e metronidazol, veiculada com propilenoglicol e polietilenoglicol (macrogol), em tecido subcutâneo de ratos e, caracterizar, histologicamente, os tecidos neoformados pós-procedimento endodôntico regenerativo, empregando o coágulo ou o coágulo suplementado com plasma rico em plaquetas (PRP), aspirado de medula óssea (AMO), ou a mistura PRP/BMA, pós-desinfecção com PTA. Estudo para avaliar a biocompatibilidade da pasta: Trinta ratos receberam 2 implantes individuais de tubos de polietileno preenchidos com PTA ou pasta de hidróxido de cálcio (PHC) e um outro tubo vazio como controle. Trinta ratos adicionais receberam tubos de polietileno contendo os veículos da pasta propilenoglicol e macrogol e um procedimento somente de incisão, sem implante de tubo (Sham). Após 7, 15, 30, 60, e 90 dias, 12 animais foram sacrificados, e os tubos foram removidos e processados histologicamente pela técnica do glicolmetacrilato e corados com hematoxilina e eosina. Os scores variaram de 0 a 3, dependendo do teor de células inflamatórias, a cápsula fibrosa foi considerada fina ou espessa, e a necrose e a calcificação foram registradas como presentes ou ausentes. Os resultados foram analisados pelo teste de Kruskal-Wallis. Ambos os materiais induziram reações moderadas aos 7 e 15 dias sendo similares ao grupo controle (p>0.05) e reduziram para grau leve a partir de 30 dias (p>0.05). Os veículos não interferiram na resposta da pasta. A pasta triantibiótica assim com seus respectivos veículos foram biocompatíveis em todos os períodos experimentais. Estudo para análise histológica dos tecidos neoformados com diferentes estratégias de engenharia tecidual: 20 dentes (40 raízes), de 2 cães da raça Beagle, foram expostos ao meio bucal pelo período de 90 dias para indução de lesão periapical. Os canais foram preparados...

This study aimed to evaluate the tissue response to the implantation of polyethylene tubes filled with a triantibiotic paste (TAP) composed of ciprofloxacin, metronidazole and minocycline conveyed with propylene glycol and polyethylene glycol (macrogol) in subcutaneous tissue of rats and characterize histologically the newly formed tissues post regenerative endodontic procedure employing the blood clot (BC) or BC supplemented with platelet-rich plasma (PRP), bone marrow aspirate (BMA) or a mixture of PRP/ BMA, post-disinfection with TAP. Study to evaluate TAP biocompatibility: Thirty rats received two individual implants of polyethylene tubes filled with TAP or calcium hydroxide paste (CHP) and another empty tube as a control. Thirty other rats received additional polyethylene tubes implants containing the paste vehicles (propylene glycol and macrogol) and an incision procedure (Sham group). After 7, 15, 30, 60, and 90 days, 12 animals were killed, and the tubes were removed and processed for histological examination. The scores ranged from 0 to 3 depending on content of inflammatory cells, the fibrous capsule was considered thin or thick, and necrosis and calcification were recorded as present or absent. The results were analyzed using the Kruskal-Wallis test. Both materials induced moderate reactions at 7 and 15 days which was similar to the control group (p> 0.05) and reduced to mild after 30 days (p> 0.05). The vehicles did not affect the tissue response to the paste. The TAP and their respective vehicles were biocompatible in all experimental periods. Study to histologically evaluate newly formed tissues after regenerative treatment: 20 teeth (40 roots), from 2 Beagle dogs, had their root canals exposed to the oral environment for 90 days to induce apical periodontitis. The canals were prepared until the apical barrier with Protaper files # F3 and the apical cementum barrier was penetrated with a #15 K-file, creating a foramen-like communication. The...

Avaliação histológica de estratégias de engenharia tecidual para a terapia endodôntica / Histological evaluation of tissue engineering strategies for endodontic therapy

O objetivo deste estudo foi avaliar a resposta tecidual ao implante de tubos de polietileno preenchidos com pasta triantibiótica (PTA) composta de ciprofloxacina, minociclina e metronidazol, veiculada com propilenoglicol e polietilenoglicol (macrogol), em tecido subcutâneo de ratos e, caracterizar, histologicamente, os tecidos neoformados pós-procedimento endodôntico regenerativo, empregando o coágulo ou o coágulo suplementado com plasma rico em plaquetas (PRP), aspirado de medula óssea (AMO), ou a mistura PRP/BMA, pós-desinfecção com PTA. Estudo para avaliar a biocompatibilidade da pasta: Trinta ratos receberam 2 implantes individuais de tubos de polietileno preenchidos com PTA ou pasta de hidróxido de cálcio (PHC) e um outro tubo vazio como controle. Trinta ratos adicionais receberam tubos de polietileno contendo os veículos da pasta propilenoglicol e macrogol e um procedimento somente de incisão, sem implante de tubo (Sham). Após 7, 15, 30, 60, e 90 dias, 12 animais foram sacrificados, e os tubos foram removidos e processados histologicamente pela técnica do glicolmetacrilato e corados com hematoxilina e eosina. Os scores variaram de 0 a 3, dependendo do teor de células inflamatórias, a cápsula fibrosa foi considerada fina ou espessa, e a necrose e a calcificação foram registradas como presentes ou ausentes. Os resultados foram analisados pelo teste de Kruskal-Wallis. Ambos os materiais induziram reações moderadas aos 7 e 15 dias sendo similares ao grupo controle (p>0.05) e reduziram para grau leve a partir de 30 dias (p>0.05). Os veículos não interferiram na resposta da pasta. A pasta triantibiótica assim com seus respectivos veículos foram biocompatíveis em todos os períodos experimentais. Estudo para análise histológica dos tecidos neoformados com diferentes estratégias de engenharia tecidual: 20 dentes (40 raízes), de 2 cães da raça Beagle, foram expostos ao meio bucal pelo período de 90 dias para indução de lesão periapical. Os canais foram preparados...

This study aimed to evaluate the tissue response to the implantation of polyethylene tubes filled with a triantibiotic paste (TAP) composed of ciprofloxacin, metronidazole and minocycline conveyed with propylene glycol and polyethylene glycol (macrogol) in subcutaneous tissue of rats and characterize histologically the newly formed tissues post regenerative endodontic procedure employing the blood clot (BC) or BC supplemented with platelet-rich plasma (PRP), bone marrow aspirate (BMA) or a mixture of PRP/ BMA, post-disinfection with TAP. Study to evaluate TAP biocompatibility: Thirty rats received two individual implants of polyethylene tubes filled with TAP or calcium hydroxide paste (CHP) and another empty tube as a control. Thirty other rats received additional polyethylene tubes implants containing the paste vehicles (propylene glycol and macrogol) and an incision procedure (Sham group). After 7, 15, 30, 60, and 90 days, 12 animals were killed, and the tubes were removed and processed for histological examination. The scores ranged from 0 to 3 depending on content of inflammatory cells, the fibrous capsule was considered thin or thick, and necrosis and calcification were recorded as present or absent. The results were analyzed using the Kruskal-Wallis test. Both materials induced moderate reactions at 7 and 15 days which was similar to the control group (p> 0.05) and reduced to mild after 30 days (p> 0.05). The vehicles did not affect the tissue response to the paste. The TAP and their respective vehicles were biocompatible in all experimental periods. Study to histologically evaluate newly formed tissues after regenerative treatment: 20 teeth (40 roots), from 2 Beagle dogs, had their root canals exposed to the oral environment for 90 days to induce apical periodontitis. The canals were prepared until the apical barrier with Protaper files # F3 and the apical cementum barrier was penetrated with a #15 K-file, creating a foramen-like communication...

Tissue reaction to a triantibiotic paste used for endodontic tissue self-regeneration of nonvital immature permanent teeth.

INTRODUCTION: The endodontic regenerative procedure (ERP), which is an alternative to calcium hydroxide-induced apexification, involves the use of a triple antibiotic paste (TAP) as a dressing material. The aim of this study was to evaluate the response of rat subcutaneous tissue to implanted polyethylene tubes that were filled with TAP or calcium hydroxide. METHODS: Thirty rats received 2 individual implants of polyethylene tubes filled with TAP or calcium hydroxide paste (CHP) and another empty tube as a control. Thirty additional rats received 2 individual implants consisting of polyethylene tubes filled with dressing material carriers (macrogol and propylene glycol) and a sham procedure. After 7, 15, 30, 60, and 90 days, 12 animals were euthanized, and the tubes and surrounding tissue were removed and processed for histology by using glycol methacrylate and stained with hematoxylin and eosin. The histological score ranged from 0 to 3 depending on the content of inflammatory cells; the fibrous capsule was considered thin or thick, and necrosis and calcification were recorded as present or absent. The results were analyzed using the Kruskal-Wallis test. RESULTS: Both dressing materials induced moderate reactions at 7 and 15 days. These reactions were similar to the control (P > .05) and reduced in intensity (to mild) from day 30 onward (P > .05). The carriers did not interfere with the reaction of the dressing materials. CONCLUSIONS: TAP and CHP were biocompatible over the different experimental periods examined.

Evaluation of rat alveolar bone response to Angelus MTA or experimental light-cured mineral trioxide aggregate using fluorochromes.

INTRODUCTION: The aim of this study was to evaluate the rat alveolar bone response after the implantation of experimental light-cured mineral trioxide aggregate (MTA) or Angelus MTA (Angelus, Londrina, Paraná, Brazil) by histological and fluorescence analysis. METHODS: Thirty Wistar Albino rats were divided into three groups. In the control group, empty polyethylene tubes were inserted into the rat alveolar sockets immediately after extraction. In the other groups, the tubes were filled with light-cured MTA or Angelus MTA. Five animals from each group were injected with calcein on day 7, alizarin on day 14, and oxytetracycline on day 21. On day 30, these animals were killed, and the right hemimaxillas were removed and histologically processed. Half of the maxillas were processed and stained with hematoxylin and eosin. The remaining maxillas were processed for fluorescence analysis and stained with Stevenel blue and alizarin red. New bone was histomorphometrically evaluated using a Merz grid. RESULTS: The light-cured MTA presented a similar response when compared with Angelus MTA; it was characterized by a mild inflammatory response and complete bone healing. In the light-cured MTA group, the fluorescence areas were more evident at 21 days, showing an increase in bone formation. However, dystrophic mineralization was observed only with Angelus MTA. CONCLUSIONS: It was concluded that both materials present a similar inflammatory response and bone healing, but dystrophic mineralization was observed only with Angelus MTA.

Estudo comparativo in vitro da microinfiltração marginal de dois sistemas adesivos em dentes decíduos e permanentes / Microleakage in vitro study of two bonding systems in permanent and deciduous teeth

O propósito deste trabalho in vitro foi o de avaliar a microinfiltração de dois sistemas adesivos: monocomponente Single Bond/3M (SB) e autocondicionante Etch & Prime 3.0/Degussa (EP) em margens de esmalte e dentina. Foram utilizados 28 molares permanentes e 28 molares decíduos, os quais receberam preparos de classe V (nas faces V e L), com margem oclusal em esmalte e a cervical em cemento-dentina, perfazendo um total de 112 preparos. Os espécimes foram divididos em 4 grupos: grupo I - decíduos + SB; grupo II - decíduos + EP; grupo III - permanentes + SB e grupo IV - permanentes + EP. Os adesivos foram utilizados de acordo com as instruções dos fabricantes e todas as cavidades foram restauradas com uma resina composta (Z100/3M). Os espécimes foram armazenados em solução fisiológica a 37ºC por 24 horas e submetidos a 800 ciclos térmicos (5-55ºC) com 10'' de imersão em cada banho, corados em solução de azul de metileno a 2 por cento por 4 h, lavados e seccionados. A avaliação foi realizada em um microscópio óptico (40 x). Os dados obtidos foram submetidos a análise estatística através do teste não paramétrico de Mann Whitney, onde concluiu-se que: em esmalte, tanto de decíduos como de permanentes, o SB apresentou o menor grau de infiltração marginal; em cemento-dentina de decíduos o EP aprsentou o menor grau de infiltração marginal e em cemento-dentina de dentes permanentes não houve diferença estatisticamente significante entre os dois sistemas adesivos