No abstract available.
Adhesives*

No abstract available.
Temporomandibular Joint*

No abstract available.
Temporomandibular Joint*

OBJECTIVES: The aim of this study was to investigate the relationship between the apical foramen morphology and the length of merged canal at the apex in type II root canal system. MATERIALS AND METHODS: This study included intact extracted maxillary and mandibular human premolars (n = 20) with fully formed roots without any visible signs of external resorption. The root segments were obtained by removing the crown 1 mm beneath the cementum-enamel junction (CEJ) using a rotary diamond disk. The distance between the file tip and merged point of joining two canals was defined as Lj. The roots were carefully sectioned at 1 mm from the apex by a slow-speed water-cooled diamond saw. All cross sections were examined under the microscope at x50 magnification and photographed to estimate the shape of the apical foramen. The longest and the shortest diameter of apical foramen was measured using ImageJ program (1.44p, National Institutes of Health). Correlation coefficient was calculated to identify the link between Lj and the apical foramen shape by Pearson's correlation. RESULTS: The average value of Lj was 3.74 mm. The average of proportion (P), estimated by dividing the longest diameter into the shortest diameter of the apical foramen, was 3.64. This study showed a significant negative correlation between P and Lj (p < 0.05). CONCLUSIONS: As Lj gets longer, the apical foramen becomes more ovally shaped. Likewise, as it gets shorter, the apical foramen becomes more flat shaped.
Academies and Institutes ; Aluminum Hydroxide ; Bicuspid ; Carbonates ; Crowns ; Dental Pulp Cavity ; Diamond ; Humans ; Tooth Apex

OBJECTIVES: The purpose of this study was to evaluate the polymerization shrinkage stress among conventional methacrylate-based composite resins and a silorane-based composite resin. MATERIALS AND METHODS: The strain gauge method was used for the determination of polymerization shrinkage strain. Specimens were divided by 3 groups according to various composite materials. Filtek Z-250 (3M ESPE) and Filtek P-60 (3M ESPE) were used as a conventional methacrylate-based composites and Filtek P-90 (3M ESPE) was used as a silorane-based composites. Measurements were recorded at each 1 second for the total of 800 seconds including the periods of light application. The results of polymerization shrinkage stress were statistically analyzed using One way ANOVA and Tukey test (p = 0.05). RESULTS: The polymerization shrinkage stress of a silorane-based composite resin was lower than those of conventional methacrylate-based composite resins (p < 0.05). The shrinkage stress between methacrylate-based composite resin groups did not show significant difference (p > 0.05). CONCLUSIONS: Within the limitation of this study, silorane-based composites showed lower polymerization shrinkage stress than methacrylate-based composites. We need to investigate more into polymerization shrinkage stress with regard to elastic modulus of silorane-based composites for the precise result.
Composite Resins ; Elastic Modulus ; Light ; Polymerization ; Polymers ; Sprains and Strains

PURPOSE: Thymidylate synthase (TS) is the target enzyme for 5-fluorouracil (5-FU). It is known that TS is related to response, and resistance, following chemotherapy due to colorectal cancer. The object of this study was to identify the clinical significance of TS as a prognostic factor, and its influence on 5-FU based chemotherapy in colorectal cancer. METHODS: We performed a retrospective study on 105 consecutive patients who were operated on, at the Department of Surgery, Korea University, College of Medicine, for colorectal cancer between Jan. 1994 and Dec. 1995. We used formalin fixed, paraffin embedded tissues of resected specimens for our study. For the semi-quantitative study, the specific monoclonal antibody, TS106, was used for immunohistochemical staining. Interpretation of the immunohistochemical staining, for intratumoral TS expression, was divided into 4 grades: intensity 0, 1 , 2 , 3 were defined as, a total absence of TS immuno staining, less than 25%, 25~50% and more than 50%, of tumor staining positive, respectively. Grades 0, 1 , and 2 were regarded as low TS expression groups and 3 regarded as a high TS expression group. We then analyzed 5-year survival rates, according to Dukes' stage, and whether systemic chemotherapy was performed, or not, according to TS expression. RESULTS: Of the 105 patients, 91 (86.7%) showed TS expression, 21 (20%) with high TS expression and 84 (80%) were low TS expression. As Dukes' stage advanced, the incidence of high expression of TS increased (P=0.048). In Dukes' stage B2, 5-year survival rates for the low TS expressed group was better than for the high TS expressed group (P=0.0052). In patients who received postoperative chemotherapy, 5-year survival rates for the low TS expressed group were better than for the high TS expressed group (P=0.049). CONCLUSION: These data suggest the expression of intratumoral TS, studied by immunohistochemical staining, is relevant to the prognosis of colorectal cancer, especially Dukes' stage B2. It is also related to the response rate of 5-FU based systemic chemotherapy in colorectal cancer.
Colorectal Neoplasms* ; Drug Therapy ; Fluorouracil ; Formaldehyde ; Humans ; Incidence ; Korea ; Paraffin ; Prognosis ; Retrospective Studies ; Survival Rate ; Thymidylate Synthase*

No abstract available.
Nipples*

PURPOSE: The aim of this study is to confirm the association of human papillomavirus with colorectal cancer. METHODS: We studied 44 patients who were received operation for colorectal cancer from 1, Jan. 1997 to 31, Dec. at Korea University Guro Hospital. We used paraffin- embedded tissue sections of colorectal adenocarcinomas and human cervical cell lines as a positive control. We also studied 10 cases of anal canal squamous cell carcinomas. The extracted DNA were analyzed by polymerase chain reaction and enzyme restriction method. RESULTS: Human papillomavirus DNA was not detected in all specimen of colorectal adenocarcinomas. But in 3 of 10 (30%) of anal canal squamous carcinomas, human papillomavirus DNA was detected. We identified this human papillomvirus DNA as type 16 by enzyme restriction technique. CONCLUSIONS: Human papillomavirus usually associated with malignant transformation are present in anal canal squamous cell carcinomas. This study also showed same result. But this association was absent from adenocarcinoma of the colon and rectum.
Adenocarcinoma ; Anal Canal ; Carcinoma, Squamous Cell ; Cell Line ; Colon ; Colorectal Neoplasms* ; DNA ; Humans* ; Korea ; Polymerase Chain Reaction ; Rectum

OBJECTIVES: The purpose of this study was to investigate the incidence of root fusion and C-shaped root canals in maxillary molars, and to classify the types of C-shaped canal by analyzing cone-beam computed tomography (CBCT) in a Korean population. MATERIALS AND METHODS: Digitized CBCT images from 911 subjects were obtained in Chosun University Dental Hospital between February 2010 and July 2012 for orthodontic treatment. Among them, a total of selected 3,553 data of maxillary molars were analyzed retrospectively. Tomography sections in the axial, coronal, and sagittal planes were displayed by PiViewstar and Rapidia MPR software (Infinitt Co.). The incidence and types of root fusion and C-shaped root canals were evaluated and the incidence between the first and the second molar was compared using Chi-square test. RESULTS: Root fusion was present in 3.2% of the first molars and 19.5% of the second molars, and fusion of mesiobuccal and palatal root was dominant. C-shaped root canals were present in 0.8% of the first molars and 2.7% of the second molars. The frequency of root fusion and C-shaped canal was significantly higher in the second molar than the first molar (p < 0.001). CONCLUSIONS: In a Korean population, maxillary molars showed total 11.3% of root fusion and 1.8% of C-shaped root canals. Furthermore, root fusion and C-shaped root canals were seen more frequently in the maxillary second molars.
Cone-Beam Computed Tomography* ; Dental Pulp Cavity* ; Incidence ; Molar* ; Retrospective Studies

OBJECTIVES: The purpose of this study was to investigate the incidence of root fusion and C-shaped root canals in maxillary molars, and to classify the types of C-shaped canal by analyzing cone-beam computed tomography (CBCT) in a Korean population. MATERIALS AND METHODS: Digitized CBCT images from 911 subjects were obtained in Chosun University Dental Hospital between February 2010 and July 2012 for orthodontic treatment. Among them, a total of selected 3,553 data of maxillary molars were analyzed retrospectively. Tomography sections in the axial, coronal, and sagittal planes were displayed by PiViewstar and Rapidia MPR software (Infinitt Co.). The incidence and types of root fusion and C-shaped root canals were evaluated and the incidence between the first and the second molar was compared using Chi-square test. RESULTS: Root fusion was present in 3.2% of the first molars and 19.5% of the second molars, and fusion of mesiobuccal and palatal root was dominant. C-shaped root canals were present in 0.8% of the first molars and 2.7% of the second molars. The frequency of root fusion and C-shaped canal was significantly higher in the second molar than the first molar (p < 0.001). CONCLUSIONS: In a Korean population, maxillary molars showed total 11.3% of root fusion and 1.8% of C-shaped root canals. Furthermore, root fusion and C-shaped root canals were seen more frequently in the maxillary second molars.
Cone-Beam Computed Tomography* ; Dental Pulp Cavity* ; Incidence ; Molar* ; Retrospective Studies