Browsing by Author "Piloto, Joana F."
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- Fracture resistance of single-tooth implant-supportedPublication . Piloto, P.A.G.; Piloto, Joana F.The purpose of this study is to identify and compare the fracture behaviour of the ceramic used in a single tooth implanted supported, see figure 1. Two different materials are tested in the abutment (ceramic and titanium). The implant is made of Titanium. Different fracture behaviour is expected, depending on the abutment material. Considering the existence of two or more different materials, with different biomechanical properties (thermal and mechanical) and also the adherence between them (bond strength), it is expectable to foresee problems under clinical conditions. Failure of the restoration is dependent on several factors. Optimum clinical design should require knowledge of failure mechanism. Besides the previous mentioned factors affecting failure, adverse environmental conditions, such as moisture and other fluids may also contribute to decrease life of this implant.
- Fracture resistance of single-tooth implant-supportedPublication . Piloto, P.A.G.; Piloto, Joana F.The purpose of this study is to identify and compare the fracture behaviour of the ceramic used in a single-tooth implant-supported. This type of prosthesis is mainly used when a single tooth replacement is needed. Two different materials are tested for the abutment (ceramic and titanium), assuming fully connection to the crown. The implant is made of titanium. The numerical simulations used the concept of continuous damage mechanics to predict crack pattern when loading the tooth in the vertical direction. The ceramic abutment grants an increase of 10% in fracture resistance and is able to accommodate a larger extension of damage material of the crown.
- Thermal stimulation of dentinal tubulesPublication . Piloto, P.A.G.; Piloto, Joana F.Dentine is a permeable mineralised tissue, made with a special geometry. The geometry presents micro tubules with variable dimensions and densities. According to Coutinho et al [l], dentine can be subdivided into fou different classes, on the number and shape ofthe tubules. This work considers the region near the cusps (class II). Dentine can be directly exposed to high or low temperature, when the tooth is under restoration or due to gingival retraction. This temperature variation can induce pain into the patient. When this thermal stimulation is applied to the enamel, the threshold value for pain due to high temperature is 45°C and the threshold value due to low temperature is 27°C [2]. This investigation aims to validate the numerical model using experimental data obtained from tests developed by Matthews [2] in the teeth of dogs. According to this investigation, the temperature and the electrical activity of two electrodes, located in with the pulp region, were measured [2], allowing for a correlation between the thermal stimulus and pain.
- Thermal stimulation of dentinal tubulesPublication . Piloto, P.A.G.; Piloto, Joana F.Dentine is a permeable mineralised tissue, made with a special geometry. The geometry presents micro tubules with variable dimensions and densities. Dentine can be subdivided into four different classes, depending on the number and shape of the tubules. Dentine can be directly exposed to high or low temperature, when the tooth is under restoration or due to gingival retraction. This temperature variation can induce pain into the patient. This investigation aims to validate the numerical model using experimental data obtained from tests developed in dog teeth. According to this investigation, the rate of temperature, threshold temperature and the neural activity are correlated allowing for a positive correlation between the thermal stimulus and pain.