RESUMO
OBJECTIVE: To evaluate and compare the responses of human incisor and premolar pulps after bleaching. STUDY DESIGN: A bleaching agent with 38% hydrogen peroxide (H(2)O(2)) was applied on the buccal surface of 10 sound lower teeth (G1: 6 premolars; G2: 4 incisors) for 45 minutes. Three premolars and 3 incisors that received only rubber/pumice prophylaxis were used as control groups G3 and G4, respectively. Two days after the bleaching procedure, the teeth were extracted and processed for histologic evaluation. RESULTS: Only in G2 (4 incisors) were any changes in the pulp detected. In the coronal pulp there was a large zone of coagulation necrosis. The radicular pulp showed mild inflammatory changes manifested as an accumulation of mononuclear cells around congested and dilated blood vessels. No pulpal damage was seen in either of the control groups (G3 and G4) or in group G1. CONCLUSION: Bleaching with 38% H(2)O(2) for 45 minutes causes irreversible pulp damage in lower incisors but not in premolars.
Assuntos
Polpa Dentária/efeitos dos fármacos , Peróxido de Hidrogênio/uso terapêutico , Oxidantes/uso terapêutico , Clareamento Dental/métodos , Adolescente , Dente Pré-Molar/efeitos dos fármacos , Profilaxia Dentária , Polpa Dentária/irrigação sanguínea , Polpa Dentária/patologia , Necrose da Polpa Dentária/induzido quimicamente , Necrose da Polpa Dentária/patologia , Dentina/efeitos dos fármacos , Dentina/patologia , Dentina Secundária/induzido quimicamente , Dentina Secundária/patologia , Humanos , Peróxido de Hidrogênio/administração & dosagem , Hiperemia/induzido quimicamente , Hiperemia/patologia , Incisivo/efeitos dos fármacos , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/patologia , Neutrófilos/efeitos dos fármacos , Neutrófilos/patologia , Odontoblastos/efeitos dos fármacos , Odontoblastos/patologia , Oxidantes/administração & dosagem , Pulpite/induzido quimicamente , Pulpite/patologia , Fatores de TempoRESUMO
PURPOSE: To evaluate the in vivo pulpal response after pulpotomy with different capping agents. In addition, the in vitro cytotoxic effects of both materials were assessed by applying them on culture of pulp cells. METHODS: For the in vivo test, the coronal pulp of 28 teeth of dogs was mechanically removed and the root pulps were capped with the following dental materials: Group 1: Pro-Root MTA (PRMTA); and Group 2 (control): calcium hydroxide saline paste (CH). After 60 days, the animals were sacrificed and the teeth processed for histological analysis. In the in vitro test, experimental extracts obtained from both capping agents were applied on the cultured MDPC-23 odontoblast-like cells. RESULTS: In the root pulps capped with PRMTA or CH, coagulation necrosis partially replaced by dystrophic calcification as well as tubular dentin matrix laid down by elongated pulp cells was observed. None or mild inflammatory response occurred beneath the capped pulpal wound. Regarding the pulpal response, PRMTA and CH presented no statistical difference. However, the teeth capped CH presented greater healthy pulp loss which resulted in convex shape of the hard barrier than PRMTA. When applied on the cultured cells, it was demonstrated that PRMTA and CH solutions decreased the cell metabolic activity by 9.9% and 29.4%, respectively. CH caused higher cytotoxic effects to the MDPC-23 cells as well as deeper healthy pulp tissue loss than PRMTA. However, similar sequence of healing occurred after pulpotomy with both dental materials.
Assuntos
Compostos de Alumínio/toxicidade , Compostos de Cálcio/toxicidade , Hidróxido de Cálcio/toxicidade , Polpa Dentária/efeitos dos fármacos , Óxidos/toxicidade , Materiais Restauradores do Canal Radicular/toxicidade , Silicatos/toxicidade , Animais , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Membrana Celular/ultraestrutura , Citoplasma/efeitos dos fármacos , Citoplasma/ultraestrutura , Polpa Dentária/citologia , Calcificações da Polpa Dentária/induzido quimicamente , Calcificações da Polpa Dentária/patologia , Capeamento da Polpa Dentária , Dentina Secundária/induzido quimicamente , Dentina Secundária/patologia , Cães , Combinação de Medicamentos , Microscopia Eletrônica de Varredura , Necrose , Odontoblastos/efeitos dos fármacos , Pulpotomia , Fatores de TempoRESUMO
PURPOSE: This study tested an in vitro model of dentin hypermineralization, aiming to simulate naturally hypermineralized dentin for bond strength studies. The effect on bond strength of a double-etching treatment on the artificially hypermineralized substrate was also evaluated. MATERIALS AND METHODS: Extracted human third molars were selected and 2 groups were formed: a group of 3 teeth, called N (normal dentin) and a group of 6 teeth, called H (hypermineralized dentin). Occlusal surfaces were ground flat to expose midcoronal dentin. Group H was subjected to artificial hypermineralization and subdivided into 2 subgroups: Ht and Hd. The exposed dentinal surfaces of group N and subgroup Ht were etched with 37% phosphoric acid for 15 s prior to bonding with Single Bond adhesive. Dentin of the subgroup Hd was etched twice (double etching) prior to bonding with Single Bond. A 4-mm-high Z100 composite buildup was created on each tooth and, after 24 h water storage, bond strengths were evaluated by the microtensile method. The data between group N and subgroup Ht and between subgroups Ht and Hd were compared using the Student's t test (alpha = 0.05). RESULTS: No significant difference was observed between bond strengths of group N and subgroup Ht (p = 0.108). Subgroup Hd was statistically different from Ht (p < 0.0001). CONCLUSIONS: Bond strengths of Single Bond to artificially hypermineralized dentin did not differ statistically from those to normal dentin substrate. The double etching approach significantly reduced bond strengths of artificially hypermineralized dentin.
Assuntos
Fosfatos de Cálcio/farmacologia , Colagem Dentária , Dentina Secundária/ultraestrutura , Condicionamento Ácido do Dente/métodos , Adesividade , Bis-Fenol A-Glicidil Metacrilato/química , Resinas Compostas/química , Dentina Secundária/induzido quimicamente , Adesivos Dentinários/química , Humanos , Microscopia Eletrônica de Varredura , Ácidos Fosfóricos/química , Dióxido de Silício/química , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração , Zircônio/químicaRESUMO
The purpose of this paper was to study the reaction of rat subcutaneous connective tissue to the implantation of dentin tubes filled with white mineral trioxide aggregate (MTA), a material that will be marketed. The tubes were implanted into rat subcutaneous tissue and the animals were sacrificed after 7 and 30 days. The undecalcified pieces were prepared for histological analysis with polarized light and von Kossa technique for mineralized tissues. Granulations birefringent to polarized light and an irregular structure like a bridge were observed next to the material; both were von Kossa positive. Also, in the dentin wall tubules a layer of birefringent granulations was observed. The results were similar to those reported for gray MTA, indicating that the mechanisms of action of the white and gray MTA are similar.
Assuntos
Compostos de Alumínio/farmacologia , Compostos de Cálcio/farmacologia , Tecido Conjuntivo/efeitos dos fármacos , Óxidos/farmacologia , Materiais Restauradores do Canal Radicular/farmacologia , Silicatos/farmacologia , Animais , Birrefringência , Dentina Secundária/induzido quimicamente , Combinação de Medicamentos , Implantes de Medicamento , Humanos , RatosRESUMO
The subject of this study was to observe the rat subcutaneous connective tissue reaction to implanted dentin tubes filled with mineral trioxide aggregate, Portland cement or calcium hydroxide. The animals were sacrificed after 7 or 30 days and the undecalcified specimens were prepared for histological analysis with polarized light and Von Kossa technique for mineralized tissues. The results were similar for the studied materials. At the tube openings, there were Von Kossa-positive granules that were birefringent to polarized light. Next to these granulations, there was an irregular tissue like a bridge that was Von Kossa-positive. The dentin walls of the tubes exhibited in the tubules a structure highly birefringent to polarized light, usually like a layer and at different depths. The mechanism of action of the studied materials has some similarity.
Assuntos
Compostos de Alumínio/farmacologia , Compostos de Cálcio/farmacologia , Hidróxido de Cálcio/farmacologia , Cimentos Dentários/farmacologia , Dentina Secundária/induzido quimicamente , Dentina/efeitos dos fármacos , Óxidos/farmacologia , Silicatos/farmacologia , Pele/patologia , Animais , Núcleo Celular/ultraestrutura , Corantes , Tecido Conjuntivo/patologia , Dentina/patologia , Dentina Secundária/patologia , Combinação de Medicamentos , Fibroblastos/patologia , Corantes Fluorescentes , Células Gigantes/patologia , Humanos , Microscopia de Polarização , Neutrófilos/patologia , Ratos , Fatores de TempoRESUMO
Some endodontists use iodoform in Sealapex in order to rend it more radiopac. This procedure is empiric and for this reason we decided to observe, histologically, if the iodoform introduces some modification in the biological properties of Sealapex. Thirty root canals of dogs' teeth were overinstrumented and filled, by lateral condensation technique, with gutta percha points and Sealapex, with or without iodoform. The iodoform was added in two different proportions: 30 mg or 112 mg for one centimeter of the base and one centimeter of the catalyst of Sealapex. The pieces were removed for histological studies, 6 months after the treatment. The histological results showed that Sealapex encourages apical closure by cementum deposition and that the addition of iodoform does not change that biological property.
Assuntos
Hidróxido de Cálcio/farmacologia , Cimentos Dentários/farmacologia , Hidrocarbonetos Iodados/farmacologia , Tecido Periapical/efeitos dos fármacos , Materiais Restauradores do Canal Radicular/farmacologia , Salicilatos , Animais , Dentina Secundária/induzido quimicamente , Cães , Guta-PerchaRESUMO
La magnitud de la desmineralización por solvatación ácida es casi tan importante como la quelación por EDTA, procesos que ocurren simultáneamente durante el tratamiento con EDTA del diente. Un 45% del mineral disuelto se debe al protón, pero esta solvatación demora más tiempo que la quelación. Al acidificarse el medio, el quelato CaEDTA se disocia. Esto junto con un aumento de la concentración de HPO=4, según el modelo de Van Dijk, haría disminuir la velocidad de desmineralización. Una estimación rápida de las concentraciones de estas especies en el diente ([Ca+2]=10-6M,[HPO=4]=10-3M,[OH-]=10-8M) nos muestra que a pH6 la reacción carece de fuerza motriz y la desmineralización por EDTA se autolimita