Vegetal polymer in repair of defects of the orbital floor: an experimental study in rabbits

Background: An experimental study was done to assess the ability of the vegetal polymer miniplates and screws to repair defects of the orbital floor.Methods: An artificial standard-sized defect was created in the bony floor of right orbit of 45 albino rabbits. The animals were divided into three experimental groups: control group (G1) involving animals with orbital floor defect and no treatment; titanium group (G2) containing animals with orbital floor defect repaired by titanium miniplates and screws; vegetal polymer group (G3) composed of animals with similar orbital floor defects repaired by vegetal polymer miniplates and screws. Throughout the course of the experiment, the animals were clinically evaluated. At 15, 30 and 60 days after surgery, the animals were killed. They were X-rayed immediately after the floor defect and at the moment of sacrifice. Histological and morphometric evaluation of inflammatory reaction and bone healing was done. Data were statistically evaluated.Results: No implants were extruded. Bone consolidation was similar in G2 and G3 and better than in G1 group animals. Inflammatory reaction was most pronounced in animals of G3 15 days after surgery, and it subsided over time.Conclusion: Vegetal polymer miniplates and screws induces small inflammatory reaction and had the ability to stimulate bone growth with good integration in the orbital floor defect allowing to consider the vegetal polymer adequate option to treat orbital floor defects. Future studies involving long-term follow-up and biomechanical tests to evaluate material resistance to traction are needed.

Critérios anatomopatológicos para melanoma maligno cutâneo: análise qualitativa de sua eficácia e revisão da literatura

São bastante conhecidos pelos patologistas o desafio e a dificuldade que algumas lesões melanocíticas apresentam no momento de seu diagnóstico. A falta de uniformidade na maneira de aplicar os critérios diagnósticos é, sem dúvida, uma das causas principais dos altos índices de discordância descritos na literatura. O objetivo deste trabalho é tentar diminuir esta discordância e, para isso, foram selecionados os 12 critérios considerados mais importantes para o diagnóstico de melanoma: 1) tamanho; 2) simetria; 3) delimitação lateral; 4) maturação; 5) disseminação pagetóide; 6) necrose/ulceração; 7) infiltrado inflamatório; 8) regressão; 9) atipias celulares; 10) mitoses; 11) melanização; 12) proliferação de células isoladas. Foram expostas as características de cada um deles e sua aplicação no diagnóstico dos melanomas, lembrando sempre as possíveis exceções, onde estes critérios podem estar presentes em lesões melanocíticas benignas. Posteriormente, em três tabelas, estabeleceu-se o diagnóstico diferencial entre melanoma e três condições melanocíticas benignas que costumam apresentar maiores dificuldades no diagnóstico diferencial. Como nenhum critério deve ser considerado isoladamente, a aplicação rigorosa do conjunto de dados aqui fornecido pode ajudar substancialmente o patologista cirúrgico generalista (não-especialista em lesões melanocíticas) a resolver alguns problemas na sua rotina diária.

Comparative Study Between Porcine Small Intestinal Submucosa and Buccal Mucosa in a Partial Urethra Substitution in Rabbits

Purpose: Several urethral conditions may require tissue substitution. One collagen-base biomaterial that recently emerged as an option is small intestinal submucosa (SIS). The aim of this study was to compare the results of SIS and buccal mucosa for urethral substitution in rabbits.Materials and Methods: Thirty-six North Folk male rabbits were randomized into three groups. In all animals, a 10 x 5 mm urethral segment was excised, and the urethral defect was repaired using a one-layer SIS patch (group I [GI]); four-layer SIS (group II [GII]); or buccal mucosa (group III [GIII]). Urethrography was performed preoperatively and after 12 weeks. After sacrifice, graft retraction was objectively measured using Scion Image (R) computer analysis and by calculation of ellipse area. The grade of fibrosis, inflammatory reaction, vascular/epithelial regeneration, and collagen III/I ratio were analyzed by hematoxylin/eosin and Picrosirius red staining.Results: Urethrography confirmed a wide urethral caliber without any signs of strictures after surgery. Urethral fistulae was diagnosed in 8.3% of cases (1 animal each group). Average graft shrinkage was 55.2% in GI; 44.2% in GII; and 57.2% in GIII (p < 0.05). The intensity of chronic inflammation, fibrosis, epithelium regeneration, and neovascularization was similar in all groups (p > 0.05). Collagen III/I ratio was higher in GII (GI: 119.6; GII: 257.2 and GIII: 115.0); p < 0.01.Conclusions: The four-layer SIS is more advantageous than the one-layer SIS and buccal mucosa for urethral substitution in rabbits.

Biocompatibilidade e biodegradabilidade de micropartículas de poli-lactato-co-glicolato na ceratite infecciosa em coelhos

Avaliaram-se a biocompatibilidade e a biodegradabilidade do sistema de liberação controlada de poli-lactato-co-glicolato (PLGA) no tratamento com ciprofloxacina das ceratites por Staphylococcus aureus em coelhos. Foram utilizados 20 coelhos, distribuídos em quatro grupos (G). Os animais dos G1, G3 e G4 foram inoculados com 2,5µL da bactéria - 108UFC, no estroma corneano. Os do G2 não receberam a aplicação do inóculo. O tratamento foi realizado com solução salina básica para os animais do G1, micropartículas de PLGA contendo ciprofloxacina nos animais dos G2 e G4 e colírio de ciprofloxacina naqueles do G3. Suabe e biópsia da superfície ocular foram coletados para cultura. Apenas um animal do G1 apresentou cultura positiva para S. aureus. Exame histológico revelou a presença bacteriana em todos os animais do G1 e em dois animais do G3. Também foi constatada reação inflamatória no local da aplicação do sistema de liberação controlada. O tratamento com micropartículas de PLGA foi eficiente no tratamento de ceratites bacterianas, ao eliminar por completo a presença do S. aureus, mas entretanto não foi completamente biocompatível e biodegradável após cinco dias.

Evaluation of tissue response to periodontal dressings: Histological study in tooth sockets of rats

Although the use of periodontal dressings is currently limited, there are some indications for their use. Selection of any material that will have direct contact with live tissues, such as periodontal dressings, should be careful in order to allow surgical wound healing. The aim of this study was to evaluate the intensity of inflammatory response and bone formation in tooth sockets of rats after implantation of three periodontal dressings. After removal of the right maxillary incisors of 84 male rats, each tooth socket received implantation of a polyethylene tube, 63 of which were filled with non-eugenol periodontal dressing and the remaining 21 tubes remained empty (control group). Histological evaluation assessed the intensity of inflammatory response and presence and location of bone tissue formation at postoperative periods of 7, 14 and 28 days. Statistical analysis was performed by the Kruskal-Wallis test at 5% significance level. Regarding the inflammatory infiltrate, at 28 days, there was statistically significant difference between one of periodontal dressings and control group (p < 0.05). Analysis of postoperative periods, showed that the control group presented statistically significant reduction in the inflammatory infiltrate comparing the 14- and 28-day periods (p < 0.05). Regarding bone tissue formation, there was difference in control group between the 7- and 28-day periods (p < 0.05). Within the experimental conditions, it may be concluded that no differences were found in the inflammatory response among the groups at 7 and 14 days and that Voco pac (TM) dressing induced a more intensive inflammatory reaction at 28 days.

Healing process of dog teeth after post space preparation and exposition of the filling material to the oral environment

Foi propósito deste estudo analisar a influência da infiltração marginal coronária no comportamento dos tecidos periapicais de dentes de cães após obturação de canal e preparo para pino. Quarenta canais de dentes de cães foram instrumentados e obturados pela técnica da condensação lateral com cones de guta percha e os cimentos Roth e Sealer 26. Após preparo para pino, o remanescente da obturação foi protegido ou não com um plug do cimento temporário Lumicon. Após exposição ao meio oral por 90 dias, os animais foram sacrificados e as peças preparadas para análise histomorfológica. A técnica de Brown e Brenn mostrou 70% de casos com infiltração de microrganismos para o cimento Roth e 20% com o Sealer 26. Quando um plug de Lumicon foi empregado ocorreu 30% de casos de infiltração de microrganismos com o cimento Roth e 0,0% com o cimento Sealer 26. Reação inflamatória crônica foi mais freqüentemente observada com o cimento Roth do que com o Sealer 26. Foi concluído que o plug de Lumicon é eficiente no controle da infiltração coronária (p=0.05) e que o Sealer 26 foi mais biocompatível e selou melhor os canais radiculares do que o cimento Roth (p=0.01).

Comparison of the biocompatibility of different root canal irrigants

The purpose of this study was to compare the reaction of rat subcutaneous connective tissue to 0.9% sterile saline, 2.5% sodium hypochlorite (NaOCl), 5.25% NaOCl and 2% chlorhexidine gluconate solution or gel. Six circles were demarcated on the dorsal skin of 24 male Wistar rats, leaving 2 cm between each circle. Using a syringe, 0.1 mL of each root canal irrigant was injected subcutaneously into 5 circles. In the 6th circle, the needle of an empty syringe was introduced into the skin, but no irrigant was injected (control group). Evaluations were undertaken at 2 h, 48 h, 14 days and 30 days post-procedure. Tissue samples were excised, embedded in paraffin blocks and 3-mu m-thick sections were obtained and stained with hematoxylin and eosin. The areas of inflammatory reaction were evaluated and analyzed statistically by ANOVA and Tukey's test. The control group showed few or no inflammatory reaction areas in the subcutaneous tissue. 0.9% saline solution, 2.0% chlorhexidine solution and 2.5% NaOCl showed a good biocompatibility, as very mild inflammatory reaction was detected at 14 days and tissue repair occurred at 30 days. 5.25% NaOCl was the most toxic irrigant, as the number of inflammatory cells remained elevated at 14 and 30 days. The group treated with 2.0% chlorhexidine gluconate gel presented a moderate inflammatory response at 14 days, which decreased at 30 days, being considered similar to that of the control group, 0.9% saline solution, 2.0% chlorhexidine solution and 2.5% NaOCl at this experimental period.

In vivo evaluation of the biocompatibility of three current bonding agents

The aim of this in vivo study was to evaluate the biocompatibility of three current bonding agents and calcium hydroxide cement. Sixty polyethylene tubes filled with the following materials: Group 1: Prime & Bond NT (PB - Dentsply, US; Group 2: Bond 1 (BO - Jeneric/Pentron, US); Group 3: Optibond Solo (OP - Kerr, US); and Group 4 (control): calcium hydroxide cement - Dycal (CH - Dentsply, US) were implanted into the connective tissue of 30 rats. After 15, 30 and 60 days, the implants were excised and the animals sacrificed. The biopsies were immersed in Karnovsky (pH, 7.2) fixative solution for 48 hours, and processed using routine histological technique. Six-micron-thick sections were cut and stained with hematoxilin and eosin and Masson's trichome technique. Microscopic evaluation was used to compare the connective tissue reactions caused by the experimental and control materials adjacent to the tube opening. At 15 days, the experimental and control materials triggered a moderate to intense inflammatory response which gave rise to a thick capsule adjacent to the tube opening. With time, the inflammatory reaction decreased. At 60 days, the connective tissue adjacent to the bonding agents exhibited a persistent inflammatory response mediated by macrophages and giant cells which were engulfing displaced resin components. on the other hand, for the control group (calcium hydroxide) no inflammatory response associated with a thin capsule adjacent to the material was observed even at the 30-day period. The hard-setting calcium hydroxide cement allowed complete healing and was considered more biocompatible than the bonding agents.

Effect of low-level laser therapy on bone repair: Histological study in rats

Background and Objectives: Bone remodeling is characterized as a cyclic and lengthy process. It is currently accepted that not only this dynamics is triggered by a biological process, but also biochemical, electrical, and mechanical stimuli are key factors for the maintenance of bone tissue. The hypothesis that low-level laser therapy (LLLT) may favor bone repair has been suggested. The purpose of this study was to evaluate the bone repair in defects created in rat lower jaws after stimulation with infrared LLLT directly on the injured tissue.Study Design/Materials and Methods: Bone defects were prepared on the mandibles of 30 Holtzman rats allocated in two groups (n = 15), which were divided in three evaluation period (15, 45, and 60 days), with five animals each. control group-no treatment of the defect; laser group-single laser irradiation with a GaAlAs semiconductor diode laser device (lambda = 780 nm; P = 35 mW t = 40 s; circle minus = 1.0 mm; D = 178 J/cm(2); E = 1.4 J) directly on the defect area. The rats were sacrificed at the preestablished periods and the mandibles were removed and processed for staining with hematoxylin and eosin, Masson's Trichrome and picrosirius techniques.Results: the histological results showed bone formation in both groups. However, the laser group exhibited an advanced tissue response compared to the control group, abbreviating the initial inflammatory reaction and promoting rapid new bone matrix formation at 15 and 45 days (P < 0. 05). on the other hand, there were no significant differences between the groups at 60 days.Conclusion: the use of infrared LLLT directly to the injured tissue showed a biostimulating effect on bone remodeling by stimulating the modulation of the initial inflammatory response and anticipating the resolution to normal conditions at the earlier periods. However, there were no differences between the groups at 60 days.

Biocompatibility of an adhesive system and 2-hydroxyethylmethacrylate

The aim of the study was to evaluate the biocompatibility of an adhesive system and a resin component when implanted into connective tissue of rats. Forty sponges embedded in both materials: Scotchbond MP (SBMP/3M - Group A) and 2 - hydroxyethyl-methacrylate (HEMA - Group B), were implanted into dorsal connective tissue of 20 animals. After 7, 15, 30, or 60 days of the implantation, the animals were sacrificed; implant sites were excised and immersed for 24 hours in Kamovisky's fixative. The samples were processed under routine histologic technique, being stained with H & E. Histological evaluation showed that both materials promoted at 7 days intense inflammatory response with predominance of neutrophils and macrophages. The intense connective reaction was replaced for fibroblastic proliferation associated with macrophages and foreign body giant cells over time. The persistent moderate inflammatory reaction adjacent to scattered fragments of materials was greater to HEMA than to the SBMP. Both experimental materials did not show acceptable biocompatibility with connective tissue of rats in spite of allowing an evident connective tissue healing.

Pulp response after application of two resin modified glass ionomer cements (RMGICs) in deep cavities of prepared human teeth

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

Tissue response to polyanionic collagen: elastin matrices implanted in rat calvaria

The tissue response to polyanionic collagen matrices, prepared from bovine pericardium and implanted subperiosteally in rat calvaria, was studied. The materials were implanted in 72 male rats (Rattus norvegicus, albinus, Holtzman), randomly divided into four groups: GI-MBP hydrolyzed for 24 h; GII-MBP hydrolyzed for 36 h; GIII-MBP hydrolyzed for 48 h; GIV-native M BP. The materials were explanted after 15, 30 and 60 days and analyzed by routine histological procedures. Except for group IV (native bovine pericardium), polyanionic collagen from groups GI, GII and GIII showed low inflammatory reaction associated with bone formation, partially or completely integrated to the cranial bone; group GIV was characterized by an intense inflammatory reaction with occasional dystrophic mineralization and with occasional bone formation at 60 days when there was a decrease in the inflammatory reaction. Thus, the MBP from groups I, II and III were biologically compatible, enhancing bone formation with a slight delay at 60 days in GII. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Bone regeneration after demineralized bone matrix and castor oil (Ricinus communis) polyurethane implantation

Innocuous biocompatible materials have been searched to repair or reconstruct bone defects. Their goal is to restore the function of live or dead tissues. This study compared connective tissue and bone reaction when exposed to demineralized bovine bone matrix and a polyurethane resin derived from castor bean (Ricinus communis). Forty-five rats were assigned to 3 groups of 15 animals (control, bovine bone and polyurethane). A cylindrical defect was created on mandible base and filled with bovine bone matrix and the polyurethane. Control group received no treatment. Analyses were performed after 15, 45 and 60 days (5 animals each). Histological analysis revealed connective tissue tolerance to bovine bone with local inflammatory response similar to that of the control group. After 15 days, all groups demonstrated similar outcomes, with mild inflammatory reaction, probably due to the surgical procedure rather than to the material. In the polymer group, after 60 days, scarce multinucleated cells could still be observed. In general, all groups showed good stability and osteogenic connective tissue with blood vessels into the surgical area. The results suggest biocompatibility of both materials, seen by their integration into rat mandible. Moreover, the polyurethane seems to be an alternative in bone reconstruction and it is an inexhaustible source of biomaterial.

Histomorphometric analysis of the repair process of autogenous bone grafts fixed at rat calvaria with cyanoacrylate

Objective: The purpose of this study was to perform histological and histometric analyses of the repair process of autogenous bone grafts fixed at rat calvaria with ethyl-cyanoacrylate adhesive. Material and Methods: Thirty-two rats were divided into two groups (n=16), Group I - Control and Group II - Adhesive. Osteotomies were made at the right parietal bone for graft obtainment using a 4-mm-diameter trephine drill. Then, the bone segments were fixed with the adhesive in the parietal region of the opposite side to the donor site. After 10 and 30 days, 8 animals of each group were euthanized and the calvarias were laboratorially processed for obtaining hematoxylin and eosin-stained slides for histological and histometric analyses. Results: An intense inflammatory reaction was observed at the 10-day period. At 30 days, this reaction was less intense, despite the presence of adhesive at the recipient-site/graft interface. Graft incorporation to the recipient site was observed only at the control group, which maintained the highest graft size at 10 and 30 days. Conclusions: Although the fragment was stable, the presence of adhesive in Group II did not allow graft incorporation to the recipient site, determining a localized, discrete and persistent inflammatory reaction.

Adesivos à base de cianoacrilato para síntese de tecido mole

FUNDAMENTOS - Adesivos teciduais têm sido muito usados para síntese de ferida, em função de ser um método indolor, rápido e de fácil execução. OBJETIVOS -Analisar e comparar compatibilidade dos adesivos, etil- cianoacrilato (Super Bonder) e butilcianoacrilato (Histoacryl), e a reparação de incisões em dorso de ratos entre o fio de sutura e os respectivos adesivos. MÉTODOS - Foram usados 15 ratos. Realizaram-se duas lojas cirúrgicas no dorso. em cada uma, foi implantado um tubo de polietileno (10mm x 1mm), os quais foram preenchidos com os adesivos Super Bonder (lado direito) e Histoacryl (lado esquerdo). As incisões, do lado esquerdo, foram coaptadas com Super Bonder, e as do lado direito, com Histoacryl. Uma incisão mediana, entre as duas incisões,foi realizada e suturada com fio de seda. Os animais foram mortos, depois de 7(sete), 35(trinta) e 120 (cento e vinte dia) dias. RESULTADOS: Os adesivos usados, no presente estudo, não promoveram reação inflamatória, quando usados para síntese das incisões. Porém, estes adesivos, quando implantados no subcutâneo, promoveram reação inflamatória até 120 (cento e vinte dia) dias, no entanto, a reação é mais intensa com Histoacryl. CONCLUSÕES: Super Bonder e Histoacryl permitem o processo cicatricial dos tecidos incisados; facilitam a sutura das incisões. Desta forma, estes podem ser utilizados para sínteses de feridas, lacerações ou incisões cutâneas.