title: Effect of Preparation Taper, Height and Marginal Design Under Varying Occlusal Loading Conditions on Cement Lute Stress: A Three Dimensional Finite Element Analysis.
abstract: To assess the effect of preparation taper, height and margin design under different loading conditions on cement lute stress. A 3-D FE model of an upper second premolar and molar was developed from CT scan of human skull using software programmes (MIMICS, Hypermesh and ANSYS). 10° and 30° taper, 3 and 5 mm preparation height and shoulder and chamfer finish lines were used. Type 1 Glass ionomer cement with 24 μm lute width was taken and the model was loaded under 100 N horizontal point load, vertical point load distributed axial load. The maximum shear stress and Von Mises stress within the cement lute were recorded. The maximum shear stresses ranged from 1.70 to 3.93 MPa (horizontal point loading), 0.66 to 3.04 MPa (vertical point loading), 0.38 to 0.87 MPa (distributed loading). The maximum Von Mises stresses ranged from 3.39 to 10.62 MPa (horizontal point loading), 1.93 to 8.58 MPa (vertical point loading) and 1.49 to 3.57 MPa (distributed loading). The combination of 10° taper and 5 mm height had the lowest stress field while the combination of 30° taper and 5 mm height had the highest stress field. Distributed axial loading shows least stress, better stress homogenization and gives a favorable prognosis for the fixed prostheses. Smaller preparation taper of 10° is biomechanically more acceptable than a 30° taper. It is desirable to decrease taper as height increases. The chamfer margin design is associated with greater local cement stresses toward the margins that could place the cement at greater risk for microfracture and failure.
authors.affiliation: Department of Prosthodontics Including Crown and Bridge and Implantology, Kothiwal Dental College & Research Centre, Mora Mustaqueem, Kanth Road, Moradabad, 244001 Uttar Pradesh India.
authors.forename: Siddhi
authors.initials: S
authors.lastname: Tripathi
authors.affiliation: Department of Prosthodontics Including Crown and Bridge and Implantology, M R Ambedkar Dental College & Hospital, Bangalore, 560015 Karnataka India.
authors.forename: Gowdagere Shamanna
authors.initials: GS
authors.lastname: Amarnath
authors.affiliation: Department of Prosthodontics Including Crown and Bridge and Implantology, M R Ambedkar Dental College & Hospital, Bangalore, 560015 Karnataka India.
authors.forename: Byrasandra Channapa
authors.initials: BC
authors.lastname: Muddugangadhar
authors.affiliation: Department of Oral & Maxillofacial Surgery, Kothiwal Dental College & Research Centre, Mora Mustaqueem, Kanth Road, Moradabad, 244001 Uttar Pradesh India.
authors.forename: Ashish
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Department of Prosthodontics Including Crown and Bridge and Implantology, College of Dental Science and Research Centre, Near Bopal ghuma road, Manipur, Ta. Sanand Dist., Ahmedabad, 382115 Gujarat India.
authors.forename: Suchismita
authors.initials: S
authors.lastname: Choudhary
keywords: Cement lute; Finish line; Finite element analysis; Height; Occlusal loading; Taper