OBJECTIVETo investigate if the Ribbond polyethylene fiber has the effect of reinforcing polymethyl methacylate.

METHODS28 specimens were fabricated and divided into 3 groups: group of chemical-cured PMMA, group of chemical-cured PMMA reinforced by stainless steel wire and group of chemical-cured PMMA reinforced by Ribbond polyethylene fiber. A three-point bending test was used to measure the flexural strength and flexural modulus of specimens. Then the data were analyzed with a one-way analysis of variance.

RESULTSThe flexural strength of chemical-cured PMMA group was (51.383 +/- 2.761) MPa, the flexural modulus was (1791.2 +/- 113.760) MPa; The flexural strength of stainless steel wire reinforced group was (58.725 +/- 1.218) MPa, the flexural modulus was (2092.76 +/- 120.28) MPa; The flexural strength of Ribbond polyethylene fiber reinforced group was (80.975 +/- 2.58) MPa, the flexural modulus was (2866.53 +/- 107.51) MPa. The one-way analysis of variance showed that the results were significant (P < 0.001). Newman-Keuls method showed that the differences among all groups were significant (P < 0.05).

CONCLUSIONThe Ribbond polyethylene fiber can raise the flexural strength and flexural modulu of polymethyl methacylate.

Dental Bonding ; Dental Materials ; chemistry ; Dental Stress Analysis ; Materials Testing ; Polyethylene ; chemistry ; Polyethylenes ; chemistry ; Polymethyl Methacrylate ; chemistry ; Stress, Mechanical ; Tensile Strength

OBJECTIVETo evaluate the clinical effectiveness of three localization methods, including methylene blue, metal clips and intraoperative colonoscopy in laparoscopic colorectal surgery.

METHODSA retrospective analysis was performed to review the clinical data of 64 patients who underwent the laparoscopic colorectal operations in Cancer Hospital of Fudan University from December 2009 to June 2012. Three methods of tumor localization were used perioperatively, including 23 cases of methylene blue, 20 of metal clips and 21 of colonoscopy.

RESULTSOperations were successfully performed in this cohort and there were no deaths or complications. In methylene blue group, intraoperative colonoscopy was performed in two cases because of the inability to visualize blue dye on the serosal surface of the intestinal wall, another 2 cases were converted to open operation because of methylene blue diffusion and inability to identify resection margin. Intraoperative colonoscopic localization was required for 3 cases of sigmoid colon or upper rectal tumor because of inaccurate tumor localization by metal clips. Poor operative exposure due to obvious bowel distension prompted the conversion to open surgery in 2 cases of colonoscopy localization group, and the accurate position of the lesion was not found in another 2 cases due to long pedunculated adenoma.

CONCLUSIONSColorectal tumor can be localized effectively by endoscopic methylene blue tattooing at a maximum of 2 tumors before operation and the method of 4-point positioning can significantly improve the accuracy of colorectal tumor localization. Tumor localization preoperatively on the day of surgery by metal clip is accurate for the right or left colon cancer. Intraoperative colonoscopy can localize tumor accurately and rapidly for rectosigmoid or descending tumor, and the incidence of bowel distension can be significantly reduced. Localization method should be considered according to the tumor location and surgical procedure.

Adult ; Aged ; Colorectal Neoplasms ; surgery ; Female ; Humans ; Laparoscopy ; methods ; Male ; Middle Aged ; Retrospective Studies ; Treatment Outcome