Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Mais filtros

Base de dados
Intervalo de ano de publicação
Dent J (Basel) ; 6(3)2018 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-30181430


This study investigated which preparation strategy for root canals leads to the best technical preparation quality, and moreover, which is perceived to be performed best by novice students. Sixty-four students were recruited to prepare one simulated root canal with each of the following: FlexMaster files (F), Mtwo files (M), and Reciproc files (R). After preparation, the students assessed the different instrument systems through a questionnaire. The technical quality of the root canal preparations was evaluated by the centering ratio of the preparation. A total of 186 prepared root canals were submitted for evaluation. With R, significantly better centered preparations were achieved when compared to M and F (p < 0.001). The students evaluated R faster than M and F, and evaluated F significantly (p < 0.05) slower than R and M. M was rated as the easiest system to learn and to handle, as well as the best at reaching the working length; therefore, it was evaluated as the overall favorite of the students. A difference was found between the students' perceptions and their achieved technical quality of root canal preparations.

BMC Oral Health ; 17(1): 141, 2017 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-29187169


BACKGROUND: Electronic apex locators (EALs) are modern devices used to determine the working length during root canal preparation. The newest endodontic motors provide an integrated EAL with auto-stop function to prevent instrumentation beyond the predefined working length during rotary root canal preparation. The aim of this study was to compare the accuracy of the auto-stop function of the VDW.Gold RECIPROC motor (VDW, Munich, Germany), the EndoPilot motor (Schlumbohm, Brokstedt, Germany) and the manual measurement with Raypex 6 (VDW, Munich, Germany) to detect the apical constriction (AC). METHODS: Ninety human teeth were chosen and randomly assigned to three experimental groups (30 teeth each): VDW.Gold RECIPROC motor continuous measuring (RCM), EndoPilot continuous measuring (ECM) and Raypex 6 manual measuring (RMM). When the measurement file reached the AC, the file was fixed in the tooth. The tooth was embedded in acrylic resin and the root tip was exposed, so that the histologic structure of the root canal and the file tip was visible for microscopic analysis. Afterwards, the distance of the file tip to the AC (DAC) was automatically computed with a specially developed software tool. RESULTS: The mean DAC were -13.18 µm (SD 88.46 µm) for RMM, -22.70 µm (SD 91.57 µm) for RCM and 18.74 µm (SD 88.11 µm) for ECM. The differences were not statistically significant (P = 0.181). The rates for instrumentation beyond the AC were not statistically different (Chi2 = 4.753, p = 0.096). CONCLUSIONS: All measurement methods showed a high accuracy in detecting the AC. The auto-stop function of these endodontic motors is a reliable addition to the endodontic armamentarium.

Preparo de Canal Radicular/instrumentação , Ápice Dentário , Instrumentos Odontológicos , Desenho de Equipamento , Humanos , Técnicas In Vitro , Distribuição Aleatória
Oral Maxillofac Surg ; 19(1): 55-60, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24998887


PURPOSE: The metabolic processes that regulate bone healing and bone induction in tissue engineering models are not fully understood. Eddy current excitation is widely used in technical approaches and in the food industry. The aim of this study was to establish eddy current excitation for monitoring metabolic processes during heterotopic osteoinduction in vivo. METHODS: Hydroxyapatite scaffolds were implanted into the musculus latissimus dorsi of six rats. Bone morphogenetic protein 2 (BMP-2) was applied 1 and 2 weeks after implantation. Weekly eddy current excitation measurements were performed. Additionally, invasive pH measurements were obtained from the scaffolds using fiber optic detection devices. Correlations between the eddy current measurements and the metabolic values were calculated. RESULTS: The eddy current measurements and pH values decreased significantly in the first 2 weeks of the study, followed by a steady increase and stabilization at higher levels towards the end of the study. The measurement curves and statistical evaluations indicated a significant correlation between the resonance frequency values of the eddy current excitation measurements and the observed pH levels (p = 0.0041). CONCLUSIONS: This innovative technique was capable of noninvasively monitoring metabolic processes in living tissues according to pH values, showing a direct correlation between eddy current excitation and pH in an in vivo tissue engineering model.

Osso e Ossos/fisiologia , Campos Eletromagnéticos , Concentração de Íons de Hidrogênio , Monitorização Fisiológica , Ossificação Heterotópica/fisiopatologia , Engenharia Tecidual/métodos , Animais , Proteína Morfogenética Óssea 2/fisiologia , Durapatita , Ratos , Estatística como Assunto , Tecidos Suporte
Tissue Eng Part C Methods ; 18(10): 740-6, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22462800


Reconstructions of facial bone defects are one of the most challenging aspects in surgical treatment of malignant diseases, large facial traumata, or congenital anomalies. High-level reconstruction techniques are often associated with an elevated morbidity by the harvest of autologous bone grafts from the patient. Tissue engineering techniques may help to solve this problem. The aim of this study was to monitor metabolic processes during cellular colonization of matrices in vivo in an established rat model for endocultivation. After implantation of computer-designed hydroxyapatite scaffolds into the latissimus dorsi muscle of six rats, 100 µg bone morphogenetic protein-2 (BMP-2) was injected twice, in week 1 and 2, directly into the center of the matrices. The development of pH value and oxygen (O2) saturation inside the matrix was followed by fiber optic detection technique over 8 weeks and analyzed by variance analyses. Bone density measurements were performed by computed tomography as well as histological evaluations. Two weeks after implantation, oxygen supply and pH value measurements had decreased significantly. In the following weeks both parameters increased and stabilized on higher levels. This is the first study reporting a reproducible method to follow metabolic processes during heterotopic osteoinduction in vivo. It was shown that in the beginning of the study pH value and O2 saturation decreased and it took several weeks to regain physiological levels. This is an important step to further understand the physiological process of bone induction.

Coristoma/metabolismo , Tecnologia de Fibra Óptica/instrumentação , Tecnologia de Fibra Óptica/métodos , Osseointegração , Técnicas de Cultura de Tecidos/métodos , Animais , Densidade Óssea/efeitos dos fármacos , Proteína Morfogenética Óssea 2/farmacologia , Coristoma/diagnóstico por imagem , Coristoma/patologia , Feminino , Humanos , Concentração de Íons de Hidrogênio , Osseointegração/efeitos dos fármacos , Oxigênio/metabolismo , Ratos , Ratos Wistar , Proteínas Recombinantes/farmacologia , Fatores de Tempo , Tecidos Suporte/química , Tomografia Computadorizada por Raios X , Fator de Crescimento Transformador beta/farmacologia