ABSTRACT
A common failure in endodontic treatment of the permanent maxillary first molars is likely to be caused by an inability to locate, clean, and obturate the second mesiobuccal (MB) canals. Because of the importance of knowledge on these additional canals, there have been numerous studies which investigated the maxillary first molar MB root canal morphology using in vivo and laboratory methods. In this article, the protocols, advantages and disadvantages of various methodologies for in-depth study of maxillary first molar MB root canal morphology were discussed. Furthermore, newly identified configuration types for the establishment of new classification system were suggested based on two image reformatting techniques of micro-computed tomography, which can be useful as a further 'Gold Standard' method for in-depth morphological study of complex root canal systems.
Subject(s)
Dental Pulp Cavity , MolarABSTRACT
PURPOSE: Small breast cysts, which can be resolved by fine-needle aspiration, are often presented as hypoechoic masses on ultrasound examinations. They can be misinterpreted as benign tumors and cause unnecessary follow-ups or biopsies. The aim of this study was to find out the proportion of atypical breast cysts, which can be resolved by needle aspiration, among hypoechoic masses less than 1 cm in size and to investigate the relationship between the characteristics of a mass and its probability of being cystic. METHODS: Between March 2003 and May 2003, we found and aspirated 119 hypoechoic masses less than 1 cm in size from 104 consecutive patients. RESULTS: Mass size ranged from 2.5 mm to 9.8 mm, with a median size of 5.5 mm. Among the 119 hypoechoic masses, 40 masses (33.6%) were cystic and 79 masses (66.4%) were solid. Among the 40 cystic masses, 37 were completely resolved by needle aspiration, one mass was reduced to half, and the 2 remaining masses were reduced to a third of their sizes. In patients in their 20's, 11.1% of the hypoechoic masses were cystic masses, the ratios for patients in their 30's, 40's, 50's, and 60's were 11.4%, 32.0%, 76.2%, and 75%, respectively (P0.05). CONCLUSION: Needle aspiration must be considered in small hypoechoic masses not speculated as definite solid masses.
Subject(s)
Humans , Acoustics , Biopsy , Biopsy, Fine-Needle , Breast Cyst , Follow-Up Studies , Needles , Ultrasonography , Ultrasonography, MammaryABSTRACT
Among three directions of distraction, the horizontal direction shows the least displacement of the condyle process and the largest overlapping surface area. We interpreted above result as the horizontal vector was the ideal direction of distraction among three directions in this patient. The mirror image of normal half side can be used as a target object of simulation surgery and also be used for evaluation of the different assumption of the surgical modalities. In conclusion, the computer simulation surgery using the mirrored image in hemifacial deformity can be an effective method for the prediction and the evaluation of the real surgery and also show the new possibility of application to the other computer simulation technology.
Subject(s)
Humans , Computer Simulation , Congenital Abnormalities , Osteogenesis, DistractionABSTRACT
The Objective of this research was to construct the multimedia database system that was necessary for the education of the practitioners and the students. To establish this system, there were technical problems as follows: 1) The processing of the images, 2) The rapid processing of the information with the computer network, 3) The development of diagnosis tools, 4) The technique to establish the database system, 5)The link between the database system and the internet, and 6) The method to educate through many cases. The analysis for diagnosis and treatment planning were provided as two parts : model analysis and cephalometric analysis. As a model analysis, arch length discrepancy and Bolton tooth ratio were provided for the part of patient information. Cephalometric analyses were provided in the part of initial diagnosis. The Cephalometric analysis ver 2.0 and the PowerCeph pro 3.3.5 were used to show Tweed, Steiner and Jarabak analysis. In the main part, Kim's analysis and some measurements were added. In the post-treatment or retention part, we show the superimposition of the cephalometrics with which you can find the effectiveness of the various orthodontic treatment. The address of this home page is "http://damis.snu.ac.kr/orthodontics"
Subject(s)
Humans , Diagnosis , Education , Education, Continuing , Internet , Multimedia , ToothABSTRACT
Presented in this paper are the experimental results that measure rapid prototyping (RP) errors in 3D medical models. We identified various factors that can cause dimensional errors when producing RP models, specifically in maxillofacial areas. For the experiment, we used a human dry skull. A number of linear measurements based on landmarks were first obtained on the skull. This was followed by CT scanning, 3D model reconstruction, and RP model fabrication. The landmarks were measured again on both the reconstructed models and the physical RP models, and these were compared with those on dry skull. We focused on major sources of errors, such as CT scanning, conversion from CT data to STL models, and RP model fabrication. The results show that the overall error from skull to RP is 0.64+/-0.36mm(0.71+/-0.66%) in absolute value. This indicates that the RP technology can be acceptable in the real clinical applications. A clinical case that has applied RP models successfully for treatment planning and surgical rehearsal is presented. Although the use of RP models is rare in the medical area yet, we believe RP is promising in that it has a great potential in developing new tools which can aid diagnosis, treatment planning, surgical rehearsal, education, and so on.
Subject(s)
Humans , Diagnosis , Education , Skull , Tomography, X-Ray ComputedABSTRACT
BACKGROUND: The impact of the immune response on cancer gene therapy using viral vectors to deliver a "suicide gene" is currently unclear. A vigrous immune response targeted at viral proteins or transgene may enhance the efficacy of tumor destruction and even augment responses to tumor antigens. These responses may involve the release of cytokines and stimulation of tumor specific cytotoxic T-lymphocytes that enhance therapeutic efficacy. On the other hand, a vigorous rapid cellular immune response may destroy cells expressing the therapeutic gene and attenuate the response to therapy. Furthermore, development of neutralizing antibody responses may prevent readministration of virus, a potentially significant limitation. Evaluating the significance of these limitations in animal models and developing solutions are therefore of obvious importance. METHODS: After retroviral transduction of mouse mesothelioma cell line(AB12) with Herpes Simplex Virus thymidine kinase (HSVtk) gene in vitro, subcutaneous flank tumors were established. To study the effect of intact immune system on efficacy of tumor erradication, the ability of the HSVtk/ganciclovir system to inhibit tumor growth was compared among normal Balb/c mice, immunodeficient Balb/c-nude and SCID mice, and Balb/c mice immunosuppressed with cyclosporin. RESULTS: Ganciclovir treatment resulted in greater inhibition of tumor growth in Balb/c mice compared with immunodeficient Balb/c-nude mice and SCID mice(in immunodeficient mice, there were no growth inhibition by ganciclovir treatment). Ganciclovir treatment resulted in greater inhibition of tumor growth in non-cyclosporin (CSA) treated Balb/c mice compared with CSA treated Balb/c mice. On day 8, mean ganciclovir-treated tumor volume were 65% of control tumor volume in Balb/c mice versus 77% control tumor volume in CSA-treated Balb/c mice. This effect was still evident during therapy (day 11 and 13). On day 13, non-CSA treated tumor volume was 35% of control tumor volume versus 60% of control tumor volume in CSA treated Balb/c mice. Duration of expression of HSVtk was not affected by the immunosuppression with CSA. CONCLUSION: These results indicate that the immune responses against retrovirally transduced cells enhance the efficacy of the HSVtk/ganciclovir system. These findings have important implications for clinical trials using currently available retrovirus vectors as well as for future vector design.