Browsing by Author "Eraslan, O."

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Direct Restoration of Endodontically Treated Teeth: a Brief Summary of Materials and Techniques
(Springer Science and Business Media B.V., 2015) Belli, S.; Eraslan, O.; Eskitascioglu, G.
The restoration of endodontically treated teeth remains a challenge. The success of the final restoration depends mostly on the structure of the remaining tooth. Although the materials and procedures available today result in successful restoration of root-filled teeth via direct (in situ) techniques, one should first consider the amount of the coronal tooth structure remaining as well as the functional requirements. Restoration using direct composite resin is a good treatment option, but polymerization shrinkage is one of the major limitations of this material. The application of various base materials under the composite resin is an effective method. Covering the cusps with the restorative material is another option to save the remaining tooth structure; however, some materials may be unsuitable in stress-bearing areas. Materials applied to the orifice of a root canal also have a major effect on tooth biomechanics. This article reviews the direct restoration of endodontically treated teeth and discusses the current materials and techniques used for this purpose. © 2015, Springer International Publishing AG.
The Effect of Cavity Shape and Hybrid Layer on the Stress Distribution of Cervical Composite Restorations
(Dental Investigations Society, 2011) Eliguzeloglu, E.; Eraslan, O.; Omurlu, H.; Eskitascioglu, G.; Belli, S.
Objectives: The aim of this finite elemental stress analysis study was to evaluate the effect of cavity shape and hybrid layer on the stress distribution of the mandibular premolar tooth under occlusal loading. Methods: The mandibular premolar tooth was selected as the model based on the anatomical measurements suggested by Wheeler. Four different mathematical models were evaluated: 1) a saucer-shaped non-carious cervical lesion restored with a composite without a hybrid layer, 2) a saucer-shaped non-carious cervical lesion restored with a composite with a hybrid layer, 3) a wedge-shaped non-carious cervical lesion restored with a composite without a hybrid layer, and 4) a wedge-shaped non-carious cervical lesion restored with a composite with a hybrid layer. A 200 N force was applied from the buccal tubercule and central fossa of the premolar tooth. The findings were drawn by the SAPLOT program. Results: In models 2 and 4, the output showed that a hybrid layer acts as a stress absorber. Additionally, when the cavity shape was changed, the stress distribution was very different. Conclusions: Cavity shape and hybrid layer play an important role in stress distribution in cervical restorations.
The Effect of Different Materials and Techniques on Stress Distribution in Cad/Cam Endocrowns
(Springer, 2020) Eskitascioglu, M.; Kucuk, O.; Eskitascioglu, G.; Eraslan, O.; Belli, S.
Computer-aided design/manufacturing (CAD/CAM) endocrowns are commonly applied to strengthen endodontically treated teeth with too much tissue loss. Monolithic or multilayer structures may be used for this purpose. Restorations made with multilayering technique may mimic natural teeth better. The purpose of this finite elemental analysis (FEA) research was to appraise the impact of different materials and application methods on the stress effect in CAD/CAM applied endocrowns. A 3-dimensional mathematical model simulating an endodontically treated mandibular first molar was modeled. The sample was then modified to imitate the ceramic endocrown applied molar tooth. Three FEA models were then created from this main model to simulate the following endocrown structures: 1: lithium disilicate reinforced glass ceramic, 2: monolithic zirconia, 3: multi-layered glass ceramic and glass-fiber endocrown (the core structure was composed of glass-fiber while the crown is prepared by glass ceramic). The SolidWorks/CosmosWorks programs were used as structural analysis programs. The materials used in the study were accepted as homogeneous and isotropic. A 300 N load was applied to the occlusal surfaces of the restored teeth. The results of the study are presented according to the von Mises criteria. The von Mises stresses recorded at the cavity base were 0.417-0.7, 0.6-0.85, and 0.083-0.25 MPa, respectively. The multilayering technique reduced stresses as compared to the other two different designs and materials and showed similar stress distributions with the natural tooth model. Models simulating teeth with a zirconia endocrown showed the highest stresses. The multilayering technique using fiber-reinforced glass ceramic as a core and glass ceramic as a crown reduced the stresses and showed stress distributions similar to natural teeth. This technique can be used to create biomimetic restorations with a core material, which mimics dentin (glass-fiber reinforced ceramic) and crown material, which mimics enamel (glass ceramic).
Effects of Naocl, Edta and Mtad When Applied To Dentine on Stress Distribution in Post-Restored Roots With Flared Canals
(Wiley, 2014) Belli, S.; Eraslan, O.; Eraslan, O.; Eskitascioglu, M.; Eskitascioglu, G.
AimTo evaluate the effect of NaOCl, EDTA and MTAD on the stress distribution and levels in roots with flared canals and three different aesthetic post systems using finite element stress analysis (FEA). MethodologyThree-dimensional (3D) FEA models simulating a maxillary incisor with excessive structural loss and flared root canals were created. The dentine of the first models of each post group was assumed as homogenous, whereas the others were deemed as having their elastic modulus affected up to 100m deep as a result of irrigation protocol (5.25 NaOCl, 17% EDTA and MTAD for 2h). A sound incisor tooth model was used as the control. Restorations were created according to the post system used (pre-fabricated fibre post (PFP)), polyethylene fibre (Ribbond) post and core build-up (RBP), and one-piece milled zirconia post and core (ZP). Ceramic crowns were added to the models. A 300-N static load was applied at the centre of the palatal surface of the models to calculate the stress distributions. The SolidWorks/Cosmosworks structural analysis programmes were used for FEA analysis. Results were presented by considering von Mises criteria. ResultsThe analysis of the von Mises stresses revealed that RBP created less stress in the remaining root dentine when compared to PFP and ZP. ZP maintained the stresses inside its body and reduced stress on the palatal surface of the root; however, it forwarded more stress towards the apical area. NaOCl-, EDTA- and MTAD-treated dentine increased the stresses within the root structure regardless of the effect of the post system used (11-15.4 MPa for PFP, 9.5-13.02 MPa for RBP and 14.2 MPa for ZP). Amongst the irrigation solutions used, EDTA and MTAD increased the stresses more than NaOCl in all models. All the irrigation solutions showed the same stress levels and distributions in the ZP model. ConclusionNaOCl-, EDTA- and MTAD- treated dentine and a rigid post with high elastic modulus may increase fracture risk in roots with flared canals by increasing the stresses within root dentine. Therefore, solutions that alter the elastic modulus of dentine less (such as NaOCl) or an individually shaped post-core system constructed with a material that has an elastic modulus close to dentine (polyethylene fibre) should be used in weak roots.
Monoblocks in Root Canals: a Finite Elemental Stress Analysis Study
(Wiley-blackwell, 2011) Belli, S.; Eraslan, O.; Eskitascioglu, G.; Karbhari, V.
Belli S, Eraslan O, Eskitascioglu G, Karbhari V. Monoblocks in root canals: a finite elemental stress analysis study. International Endodontic Journal, 44, 817-826, 2011. Aim To investigate using finite element stress analysis (FEA) primary, secondary and tertiary monoblocks created either by adhesive resin sealers or by different adhesive posts and to evaluate the effect of interfaces on stress distribution in incisor models. Methodology Seven maxillary incisor FEA models representing different monoblocks using several materials were created as follows: (a) primary monoblock with Mineral Trioxide Aggregate; (b) secondary monoblock with sealer (MetaSEAL) and Resilon; (c) tertiary monoblock with EndoREZ; (d) primary monoblock with polyethylene fibre post-core (Ribbond); (e) secondary monoblock with glass-fibre post and resin cement; (f) tertiary monoblock with bondable glass-fibre post; (g) tertiary monoblock with silane-coated ceramic post. A 300 N load was applied from the palatal surface of the crown with a 135 degrees angle to the tooth long axis. Materials used in the study were assumed to be homogenous and isotropic except the glass-fibre post; the results are expressed in terms of von Mises criteria. Results Maximum stresses were concentrated on force application areas (18-22.1 MPa). The stresses within the models increased with the number of interfaces both for the monoblocks created by the sealers (1.67-8.33 MPa) and for the monoblocks created by post-core systems (1.67-11.7 MPa). Conclusions Stresses within roots increased with an increase in the number of the adhesive interfaces. Creation of a primary monoblock within the root canal either by an endodontic sealer or with an adhesive post-core system can reduce the stresses that occur inside the tooth structure.
Retraction: Stress Distribution in Cad/Cam Endocrowns Produced Via Different Materials and Techniques: a Numerical Simulation (Retraction of Vol 52, Pg 812, 2020)
(Springer, 2023) Eskitascioglu, M.; Kucuk, O.; Eskitascioglu, G.; Eraslan, O.; Belli, S.
Stress Distribution in Cad/Cam Endocrowns Produced Via Different Materials and Techniques: a Numerical Simulation
(Springer, 2022) Eskitascioglu, M.; Kucuk, O.; Eskitascioglu, G.; Eraslan, O.; Belli, S.
Computer-aided design/manufacturing (CAD/CAM) endocrowns are commonly applied for the strengthening of endodontically treated teeth with excessive tissue loss. Monolithic or multilayer structures may be used for this purpose. Restorations made with multilayering techniques may better mimic natural teeth. This study assessed the impact of different materials and application methods on the stress state of CAD/CAM endocrowns. To this end, a 3D FEM model simulating an endodontically treated mandibular first molar was elaborated. The sample was then modified to imitate the ceramic endocrown-applied molar tooth. Three FEM models were then developed from this main model to simulate the following endocrown structures: (1) lithium disilicate reinforced glass ceramic, (2) monolithic zirconia, and (3) multilayered glass ceramic and glass-fiber endocrown (i.e., a glass-fiber core structure and glass ceramic crown). The SolidWorks/Cosmosworks software packages were used for structural analysis. The materials used in the study were treated as homogeneous and isotropic. A 300 N load was applied to the occlusal surfaces of the restored teeth. The von Mises stresses were calculated at the cavity base, ranging from 0.417-0.700 MPa, 0.600-0.850 MPa, and 0.083-0.250 MPa, respectively. The multilayering technique provided the lowest stresses and stress distributions comparable with the natural tooth model. Models of teeth restored with zirconia endocrowns showed the highest stresses and were the least applicable in dental pracice.