Bilinear elastic property of the periodontal ligament for simulation using a finite element mandible model.
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This study aimed to introduce a procedure for determining the bilinear elastic moduli (E1 and E2) of the periodontal ligament for a mathematical tooth model to analyse stress in the mandible. The bone and tooth morphology were scanned from a dry skull and an extracted intact tooth, respectively, and reconstructed in a three-dimensional finite element model. The model showed good agreement with previously reported in vivo premolar movement when an E1 for the first phase tooth movement of 0.05 MPa and an E2 for the second phase of 8.0 MPa with epsilon(12) of 0.075 were adopted. The mandible model analysis indicated that a remarkably high maximum compressive stress in the cervical cortical bone and the tensile stress in areas of masticatory muscle attachment were found. Future stress analyses using a jaw model may follow the process of determination of bilinear moduli to enhance accurate simulation with less calculation time. (+info)
Implant therapy and apical actinomycosis: case report.
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Treatment of periapical actinomycosis includes extraction of the involved tooth; however, indications for and timing of implant therapy remain unclear. In this case report, we describe treatment of apical actinomycosis in a 63-year-old woman following tooth extraction. After monitoring the patient for 6 months, implant therapy was carried out and remained successful after 1 year follow-up. (+info)
Molars extraction for bone graft study in rabbits.
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Comparison of cone beam CT device and field of view for the detection of simulated periapical bone lesions.
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OBJECTIVE: We aimed to assess the diagnostic accuracy of different cone beam CTs (CBCTs) and the influence of field of view (FOV) in diagnosing simulated periapical lesions. METHODS: 6 formalin-fixed lateral mandibular specimens from pigs were used for creating 20 standardized periapical bone defects. 18 roots were selected for the control group. Three CBCT devices [Accuitomo 3D(R) (Morita, Kyoto, Japan), NewTom 3G (Quantitative Radiology, Verona, Italy) and Scanora(R) (Soredex, Tuusula, Finland)] and three FOVs (NewTom 3G(R) FOV 6, 9 and 12 inches) were used to scan the mandible. Five observers assessed the images, using a five-point probability scale for the presence of lesions. Specificity, sensitivity and areas under the receiver operating characteristic (ROC) curves were calculated. RESULTS: Sensitivity ranged from 72% to 80%. Specificity ranged from 60% to 77%. A difference in scoring between Scanora and the other two devices existed only in the control group. ROC analysis for different FOVs showed a decreased sensitivity with an increasing FOV, but this difference was not significant. CONCLUSION: the control group, there was a difference between the CBCT devices regarding their specificity. FOV size did not show any difference in diagnostic performance. In cases in which conventional radiographic methods in combination with clinical evaluation are not sufficient, CBCT may be the method of choice to assess periapical pathology. CBCT examinations should be complementary to a clinical examination and FOV adaptation can be utilized to keep the dose to the patient as low as possible. (+info)