Background: Since the diagnosis of non-displaced longitudinal fractures present difficulties for the dentist, three-dimensional evaluation is necessary.
Objectives: The aim of this study is to demonstrate the accuracy of cone beam computed tomography (CBCT) in detecting dental root fractures in vitro.
Materials And Methods: An in vitro model consisting of 210 recently extracted human mandibular teeth was used. Root fractures were created by mechanical force. The teeth were placed randomly in the empty dental alveoli of a dry human mandible and 15 different dental arcs were created. Images were taken with a unit Iluma ultra cone-beam CT scanner (Imtec Corporation, Germany). Three dental radiologists separately evaluated the images.
Results: According to the fracture types and fracture presence, there was an overall statistically significant agreement between the key and readings. Kappa values for intra observer agreement ranged between 0.705 and 0.804 indicating that each observer gave acceptable ratings for the type and presence of fractures.
Conclusions: Detailed information about root fractures may be obtained using CBCT.
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http://dx.doi.org/10.5812/iranjradiol.11485 | DOI Listing |
BMC Oral Health
December 2024
Department of Conservative Dentistry, Faculty of Dentistry, Minia University, Minia, Egypt.
Objectives: To compare the mechanical performance of partially replaced (repaired) intra-coronal restorations to totally replaced ones in root canal-treated teeth.
Methods: Thirty maxillary second premolars were selected according to strict criteria, mounted on moulds, and had mesio-occluso-distal (MOD) cavities prepared. Resin composite restorative material was used to perform the initial restoration, followed by aging procedures using thermo-mechanical cycling fatigue to replicate six months of intraoral aging.
Clin Oral Investig
December 2024
Departament of Clinic Dentistry, UFF- Universidade Federal Fluminense, Niterói, RJ, Brazil.
Objectives: This study aimed to investigate cracked teeth and vertical root fracture observable on micro-CT images of extracted roots of mandibular incisors, after fiber post removal.
Materials And Methods: Thirty mandibular incisors were selected with any degree of slight incisal wear inspected with the aid of a stereomicroscope under 12x magnification, in order to have a group of young adult specimens according to the criteria of Hugoson et al. A sample of twelve mandibular incisors were selected, aged between 20 and 30 years old, with similar dentine volume and thickness.
Sci Rep
December 2024
School of Mechanical Engineering, Yangtze University, Jingzhou, 434023, China.
The design of drill pipe joint thread with unequal taper is proposed to investigate the fracture failure of the API NC38 used in the drill pipe joint of the SU36-8-4H2 well. The effect of changes in thread taper on the stress distribution and mechanical properties of drill pipe joints is analyzed and compared with the API standard thread to determine the optimal thread structure with unequal taper. The results reveal highly concentrated stress at the last engaged thread root of API NC38 single-shoulder thread (SUT) may cause early yield failure of the joint threads.
View Article and Find Full Text PDFDent J (Basel)
November 2024
Department of Prosthetic Dental Science, College of Dentistry, Jazan University, Jazan 45142, Saudi Arabia.
: This study aimed to investigate the fracture strength of a novel-designed Zirconia crown before and after access opening, and to evaluate the mode of fracture and the time needed for initial penetration through the crown. : This study involved the design and testing of 60 zirconia crowns, divided into three groups (20 crowns each) to compare different structural designs. Group 1 (Control) used a conventional full zirconia crown.
View Article and Find Full Text PDFOrthop Surg
December 2024
Department of Orthopaedics, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China.
Objective: There are many advantages to stabilize the posterior pelvic ring injuries with a transiliac-transsacral (TITS) screw percutaneously. To identify the correct entry point and insert a guidewire accurately for a TITS screw, we propose a method of specifying the optimal entry point, and introduce a technique of enabling freehand placement of a guidewire with fluoroscopic guidance.
Methods: In this retrospective study, 116 patients who underwent pelvic CT scans and pelvic lateral radiographs at our institution from January 2020 to April 2022 were enrolled.
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