Electromagnetic tracker feasibility in the design of a dental superstructure for edentulous patients

The success of the osseointegration concept and the Branemark protocol is highly associated to the accuracy in the production of an implant-supported prosthesis. One of most critical steps for long-term success of these prosthesis is the accuracy obtained during the impression procedure, which is affected by factors such as the impression material, implant position, angulation and depth. This paper investigates the feasibility of 3D electromagnetic motion tracking systems as an acquisition method for modeling full-arch implant-supported prosthesis. To this extent, we propose an implant acquisition method at the patient mouth and a calibration procedure, based on a 3D electromagnetic tracker that obtains combined measurements of implant's position and angulation, eliminating the use of any impression material. Three calibration algorithms (namely linear interpolation, higher-order polynomial and Hardy multiquadric) were tested to compensate for the electromagnetic tracker distortions introduced by the presence of nearby metals. Moreover, implants from different suppliers were also tested to study its impact on tracking accuracy. The calibration methodology and the algorithms employed proved to implement a suitable strategy for the evaluation of novel dental impression techniques. However, in the particular case of the evaluated electromagnetic tracking system, the order of magnitude of the obtained errors invalidates its use for the full-arch modeling of implant-supported prosthesis.This work has been supported by FCT – Fundação para a Ciência e Tecnologia in the scope of the Ph.D. grant SFRH/BD/68270/2010 and the project EXPL/BBB-BMD/2146/2013

Automatic modeling of an orthotic bracing for nonoperative correction of Pectus Carinatum

Pectus Carinatum is a deformity of the chest wall, characterized by an anterior protrusion of the sternum, often corrected surgically due to cosmetic motivation. This work presents an alternative approach to the current open surgery option, proposing a novel technique based on a personalized orthosis. Two different processes for the orthosis' personalization are presented. One based on a 3D laser scan of the patient chest, followed by the reconstruction of the thoracic wall mesh using a radial basis function, and a second one, based on a computer tomography scan followed by a neighbouring cells algorithm. The axial position where the orthosis is to be located is automatically calculated using a Ray-Triangle intersection method, whose outcome is input to a pseudo Kochenek interpolating spline method to define the orthosis curvature. Results show that no significant differences exist between the patient chest physiognomy and the curvature angle and size of the orthosis, allowing a better cosmetic outcome and less initial discomfort.The authors acknowledge to Foundation for Science and Technology (FCT) - Portugal for the fellowships with the references: SFRH/BD/74276/2010; SFRH/BD/68270/2010; UMINHO/BI/95/2012; and, SFRH/BPD/46851/2008. This work was also supported by FCT R&D project PTDC/SAUBEB/103368/2008

Stressful Life Events and Distress in Breast Cancer:A 5-Years Follow-Up

Antecedentes/Objetivo El estrés psicosocial ha demostrado tener un impacto en la evolución del cáncer de mama (CM). Este estudio tiene como objetivo explorar el impacto de la psicoterapia y de los acontecimientos vitales estresantes (AVE) en la supervivencia de pacientes con CM. Método 113 mujeres con CM recibieron psicoterapia positiva o terapia cognitivo-conductual para manejar el estrés y 37 se incluyeron como grupo control. Se analizaron los efectos de la reducción de la Escala de Ansiedad y Depresión Hospitalaria (HADS) y de los AVE sobre la recurrencia a los cinco años, así como el efecto de recibir psicoterapia y del tipo de enfoque d esta sobre la supervivencia. Resultados La reducción de un punto en la HADS después de recibir psicoterapia predijo un menor riesgo de recurrencia, OR = 0,84, p = 0,037, IC 95% = 0,71-0,99. Además, cada aumento en el número de AVE vividos como amenazantes (OR = 1,92; p = 0,028, 95% CI = 1,07-3,43) se relacionó con una mayor recurrencia. Conclusiones Los resultados indican la necesidad de estudiar no solo la presencia de un evento potencialmente impactante en la conducta (psicoterapia o AVE) sino el efecto especifico que ha tenido en cada individuo

Assessment of 3D scanners for modeling Pectus Carinatum corrective bar

Pectus Carinatum (PC) is a chest deformity consisting on the anterior protrusion of the sternum and adjacent costal cartilages. Non-operative corrections, such as the orthotic compression brace, require previous information of the patient chest surface, to improve the overall brace fit. This paper focuses on the validation of the Kinect scanner for the modelling of an orthotic compression brace for the correction of Pectus Carinatum. To this extent, a phantom chest wall surface was acquired using two scanner systems - Kinect and Polhemus FastSCAN - and compared through CT. The results show a RMS error of 3.25mm between the CT data and the surface mesh from the Kinect sensor and 1.5mm from the FastSCAN sensor.The authors acknowledge to Foundation for Science and Technology (FCT) - Portugal for the fellowships with the references: UMINHO/BI/95/2012; SFRH/BD/68270/2010; SFRH/BD/74276/2010 and SFRH/BPD/46851/2008. This work was also supported by FCT R&D project PTDC/SAU-BEB/103368/2008