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dc.contributor.authorRobert, Denisen_US
dc.date.accessioned2020-03-04T17:17:43Z
dc.date.available2020-03-04T17:17:43Z
dc.date.issued1982
dc.date.submitted1982
dc.identifier.other8885070
dc.identifier.otherb14399143
dc.identifier.urihttps://hdl.handle.net/2144/39727
dc.descriptionPLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.en_US
dc.descriptionSome colored photographs also included.en_US
dc.descriptionThesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry (Operative Dentistry/Biomaterials), 1982.en_US
dc.descriptionBibliography: leaves 78-83.en_US
dc.description93,981 c.1 94,455 c.2.en_US
dc.description.abstractThe present study was undertaken to determine if self-threading pins bent to a certain angle have deleterious effects on the tensile strength of a pin-restoration system. The effects of two methods of bending pins, the use of TMS bending tool and the use of an amalgam condensing instrument exerting a direct pushing action on the pin, were compared using a tensil strength test and a photoelastic evaluation. Forty six extracted teeth were prepared to receive one self-threading pin. Each pin, 2 mm long, was bent, using either method, at 15 degrees, 30 degrees, 45 degrees and 60 degrees. A group of unbent pins was left as control. Amalgam was condensed around the pin, completely embedding it. Each specimen was tested in a Intron machine for tensile strength. In the second part of the study, a photoelastic plastic model was used to represent a tooth with lost coronal structures, in which a self threading pin was inserted. The two bending methods were compared for stress production. The results of this study indicated a significant loss of tensile strength of a pin-restoration system when pins were bent at an angle greater than 30 degrees for the bending tool method and greater than 15 degrees with the amalgam condenser method. Furthermore, stresses generated in the tooth by the bending methods were greater with the use of an amalgam condenser than a bending tool. These findings lead to the following conclusions: - Pins should not be bent more than 30 degrees when a bending tool is used. - Pins should not be bent more than 15 degrees when an amalgam condenser is used. - The use of a bending tool is strongly recommended because it does not produce as much stress in dentin as an amalgam condenser.en_US
dc.language.isoen_US
dc.publisherBoston Universityen_US
dc.rightsThis work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.en_US
dc.subjectDental amalgamen_US
dc.subjectDental pinsen_US
dc.titleEvaluation of retention in amalgam after bending pins and the associated stresses produced during the bending proceduresen_US
dc.typeThesis/Dissertationen_US
etd.degree.nameMaster of Science in Dentistryen_US
etd.degree.levelmastersen_US
etd.degree.disciplineOperative Dentistry/Biomaterialsen_US
etd.degree.grantorBoston Universityen_US


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