Cortical support is an important factor, as the engagement of the fixture in strong compact bone offers an increased load-carrying capacity and initial stability. Because of the poor bone quality in the posterior mandible and other anatomic considerations, it has been suggested that implant fixtures be placed in these locations with apical engagement of the lingual cortical plate for so-called bicortication. The purpose of this investigation was to determine the effect of cortical engagements and in addtion polyoxymethylene (POM) intramobile connector(IMC) of IMZ implant on implant load transfer in edentulous posterior segment of mandible, using three-dimensional(3D) finite element analysis models composed of cortical and trabecular bone involving single implant. Variables such as (1) the crestal peri-implant defect, (2) the apical engagement of lingual cortical plate, (3) the occlusal contact position (a vertical load at central fossa or buccal cusp tip), and (4) POM IMC were investigated. Stress patterns were compared and interfacial stresses along the bone-implant interface were monitored specially. Within the scope of this study, the following observations were made. 1) Offset load and angulation of fixture led to increase the local interfacial stresses. 2) Stresses were concentrated toward the cortical bones, but the crestal peri-implant defect increased the interfacial stresses in trabecular bone. 3) For the model with bicortication, it was noticed that the crestal cortical bone provided more resistance to the bending moment and the lingual cortical plate provided more support for the vertical load. But Angulaton problem of the fixture from the lingual cortical engagement caused the local interfacial stress concentrations. 4) It was not clear that POM IMC had the effect on stress distribution under the present experimental conditions, expecially for the cases of crestal peri-implant defect.
Finite Element Analysis* ; Mandible*

The dental profession is currently experiencing a technology explosion. Processes are being replaced by modern, inexpensive, and precise techniques that can be used to solve complex restorative problems. Electrical discharge machining (DEM, known as spark erosion in Europe) is a nonconventional, industrial technique that has application in dentistry. EDM may be defined as a metal removal process using a series of sparks to erode material from a workpiece in a liquid medium under carefully controlled conditions. EDM is recently adopted in the dental laboratory to fabricate precision attachments, hybrid telescope crowns, Ti-ceramic crowns. EDM has also been used to achieve a passive precision metalto-metal fit between the substructure bar and the removable superstructure and to correct the fit of implant retained restorations. in this article, a brief history and explanation of EDM is discussed and a description of the use of this process for fabricating attachments and crowns or for correcting the fit of cast restorations is presented.
Crowns ; Cytochrome P-450 CYP1A1 ; Dentistry ; Explosions ; Laboratories, Dental ; Telescopes

For many years, healing membranous bone fractures have been known to show a persistent lucency at the fracture interface. Radiographic follow-up has proven to be of little value as a guideline for healing of mandibular fractures. Recently, a fracture has been treated by rigid internal fixation by metallic plate and screws rather than closed reduction and wire fixation, we expected that some difference in the radiographic features of fracture healing. To investigate these questions we undertook a retrospective radiographic and clinical analysis of 33 followed patients with fractures of the body and angle of the mandible from 1993 to 1997. There were 26 male and 7 female patients ranging in age between 5 and 74 years, with an average of 29.7 years. All patients were managed by open reduction with metallic plates and screws. The length of follow-up ranged from 9 to 187 weeks. Total 81 radiographic follow-up films were obtained and divided into 3 grades according to the degree of radiolucency of fracture lines; grade 0 radiolucent fracture line and no evidence of fracture interface calcification, grade 1 decreased radiolucent area and evidence of fracture interface calcification, and grade 2 disappearance of fracture line.Until follow-up of 8 weeks, all of the radiographs showed grade 0. From 8 weeks to 16 weeks, 62.5 percent showed grade 0 and 37.5 percent showed grade 1. From 16 weeks to 48 weeks, 38.5 percent showed grade 1 and 61.5 percent showed grade 2. After follow-up of 48 weeks, all showed grade 2.In this study we have shown that the radiographic disappearance of mandibular fracture lines was usually accomplished by 48 weeks. We feel that radiographic union of the mandible is lagging well behind clinical union, but disapperance of the fracture line in rigidly fixated mandibular fracture was occurred earlier than healed by fibrous union. We propose that radiographic union of the mandible by approximately 1 year can be a guideline for the normal mandibular bone healing.
Female ; Follow-Up Studies* ; Fracture Healing ; Fractures, Bone ; Humans ; Male ; Mandible ; Mandibular Fractures* ; Retrospective Studies

No abstract available.

No abstract available.
Avidin*

PURPOSE: Hyperhomocysteinemia has been identified as an independent risk factor in arterial and venous thrombosis. Mutations in genes encoding methylenetetrahydrofolate reductase (MTHFR), involved in the metabolism of homocysteine, may account for reduced enzyme activity and elevated plasma homocysteine levels. In this study, we investigated the interrelation of MTHFR C677T genotype and level of homocysteine in patients with arterial and venous thrombosis. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 146 patients who were diagnosed as having arterial and venous thrombosis. We excluded patients diagnosed with atrial fibrillation. We examined routinely the plasma concentration of total homocysteine level and MTHFR C677T polymorphism for evaluation of thrombotic tendency in all patients. Screening processes of MTHFR C677T polymorphism were performed by real-time polymerase chain reaction. RESULTS: Investigated groups consisted of thrombotic arterial occlusion in 48 patients and venous occlusion in 63 patients. The distribution of the three genotypes was as follows: homozygous normal (CC) genotype in 29 (26.1%), heterozygous (CT) genotype in 57 (51.4%), and homozygous mutant (TT) genotype in 25 (22.5%) patients. There were no significant differences among individuals between each genotype group for baseline characteristics. Plasma concentration of homocysteine in patients with the TT genotype was significantly increased compared to the CC genotype (P<0.05). CONCLUSION: We observed a significant interaction between TT genotypes and homocysteine levels in our results. The results might reflect the complex interaction between candidate genes and external factors responsible for thrombosis.
Atrial Fibrillation ; Genotype ; Homocysteine* ; Humans ; Hyperhomocysteinemia ; Mass Screening ; Medical Records ; Metabolism ; Methylenetetrahydrofolate Reductase (NADPH2)* ; Plasma* ; Real-Time Polymerase Chain Reaction ; Retrospective Studies ; Risk Factors ; Thrombosis ; Venous Thrombosis

No abstract available.
Fingers*

No abstract available.
Blepharoplasty* ; Skin*

PURPOSE: The purpose of this study was to determine whether Fas-L expression is associated with increased apoptotic induction of tumor-infiltrating lymphocytes (TIL) in human gastric carcinomas. MATERIALS AND METHODS: The author analysed 38 cases of early gastric carcinoma (EGC) and 61 cases of advanced gastric carcinoma (AGC) who received gastric resection, in whom the number of diffuse type was 38 cases and the number of intestinal type was 61 cases. The author used immunohistochemical staining for Fas, Fas-L and CD45, and TUNEL in situ apoptosis detection kit. TIL were detected by CD45 and apoptosis of TIL were detected by CD45 expression and TUNEL positivity on serial histologic sections. RESULTS: Fas-L was localized to neoplastic cells in 61% (23/38) of EGC group and 66% (40/61) of AGC group. The extent of Fas-L expression was variable, with both Fas-L positive and negative neoplastic region occuring within tumors. TIL adjacent to Fas-L expressing tumor region were decreased in number and TIL adjacent to FasL-negative tumor region were increased in number; apoptotic induction of TIL showed just the opposite pattern (p<0.05). Fas expression was found essentially homogeneously throughout the tumor mass independent of tumor stage. Fas expression showed 64% (39/61) of intestinal type and 68% (26/38) of diffuse type. Labeling indices for tumoral apoptosis in EGC and AGC were 6.72% and 7.13%, respectively and this difference was statistically insignificant. Co-expression of Fas-L and Fas, which occurred over large areas of the tumors, did not result in an enhanced rate of tumor cell apoptosis. In addition, factors such as tumor stage and other prognostic factors were not concerned in Fas and Fas-L expression, number of TIL and apoptotic induction. CONCLUSION: These findings suggest Fas-mediated apoptotic depletion of TIL in response to Fas-L expression by stomach cancers, and provide the evidence to support the Fas counterattack as a mechanism of immune escape in gastric cancer. In addition, gastric carcinoma cells of the intestinal and diffuse type did not differ in their expression of the apoptotic receptor Fas.
Apoptosis* ; Humans ; In Situ Nick-End Labeling ; Lymphocytes, Tumor-Infiltrating ; Stomach Neoplasms ; United Nations

No abstract available.
Blepharoptosis*