The Experts below are selected from a list of 2181 Experts worldwide ranked by ideXlab platform

Amir Ghasemi - One of the best experts on this subject based on the ideXlab platform.

  • the effect of composite thickness on the stress distribution pattern of restored Premolar teeth with cusp reduction
    Journal of Prosthodontics, 2017
    Co-Authors: Narges Panahandeh, Hassan Torabzadeh, Nargess Ziaee, Bahman Tootiaee, Mina Mahdian, Amir Ghasemi
    Abstract:

    Purpose Different thicknesses of restorative material can alter the stress distribution pattern in remaining tooth structure. The assumption is that a thicker composite restoration will induce a higher fracture resistance. Therefore, the present study evaluated the effect of composite thickness on stress distribution in a restored Premolar with cusp reduction. Materials and Methods A 3D solid model of a Maxillary Second Premolar was prepared and meshed. MOD cavities were designed with different cusp reduction thicknesses (0, 0.5, 1, 1.5, 2.5 mm). Cavities were restored with Valux Plus composite. They were loaded with 200 N force on the occlusal surface in the direction of the long axis. Von Mises stresses were evaluated with Abaqus software. Results Stress increased from occlusal to gingival and was maximum in the cervical region. The stressed area in the palatal cusp was more than that of the buccal cusp. Increasing the thickness of composite altered the shear stress to compressive stress in the occlusal area of the teeth. Conclusion The model with 2.5 mm cusp reduction exhibited the most even stress distribution.

Dhirawat Jotikasthira - One of the best experts on this subject based on the ideXlab platform.

  • Biochemical and Clinical Assessments of Segmental Maxillary Posterior Tooth Intrusion.
    International journal of dentistry, 2017
    Co-Authors: Jintana Tasanapanont, Tanapan Wattanachai, Janya Apisariyakul, Peraphan Pothacharoen, Siriwan Ongchai, Prachya Kongtawelert, Marit Midtbø, Dhirawat Jotikasthira
    Abstract:

    Objective. To compare chondroitin sulphate (CS) levels around Maxillary Second Premolars, first molars, and Second molars between the unloaded and the loaded periods and to measure the rates of intrusion of Maxillary posterior teeth during segmental posterior tooth intrusion. Materials and Methods. In this prospective clinical study, 105 teeth (from 15 patients exhibiting anterior open bite and requiring Maxillary posterior tooth intrusion) were studied. Competitive ELISA was used to detect CS levels. Dental casts (during the unloaded and loaded periods) were scanned, and posterior tooth intrusion distances were measured. Results. During the unloaded period, the median CS levels around Maxillary Second Premolars, first molars, Second molars (experimental teeth), and mandibular first molars (negative control) were 0.006, 0.055, 0.056, and 0.012 and during the loaded period were 2.592, 5.738, 4.727, and 0.163 ng/μg of total protein, respectively. The median CS levels around experimental teeth were significantly elevated during the loaded period. The mean rates of Maxillary Second Premolar and first and Second molar intrusion were 0.72, 0.58, and 0.40 mm/12 weeks, respectively. Conclusions. Biochemical and clinical assessments suggested that the segmental posterior tooth intrusion treatment modality with 50 g of vertical force per side was sufficient. Trial Registration. The study is registered as TCTR20170206006.

  • tbx22 mutation associated with cleft lip palate hypodontia and limb anomaly
    The Cleft Palate-Craniofacial Journal, 2012
    Co-Authors: A. Kaewkhampa, Dhirawat Jotikasthira, Sutti Malaivijitnond, Piranit Nik Kantaputra
    Abstract:

    Mutations in TBX22 are known causes of cleft palate with/without ankyloglossia. We identified a hemizygous missense c.452G>T (p.Arg151Leu) mutation in a Thai boy who had unilateral complete cleft lip and palate, agenesis of a Maxillary Second Premolar, ankyloglossia, hypoplastic carpal bones, and hypoplastic right thumb. Our study has demonstrated that TBX22 mutation is associated not only with cleft palate and ankyloglossia, but also cleft lip and palate and tooth agenesis. Phenotypic variability caused by a single nucleotide substitution is clearly demonstrated.

  • TBX22 mutation associated with cleft lip/palate, hypodontia, and limb anomaly.
    The Cleft Palate-Craniofacial Journal, 2011
    Co-Authors: A. Kaewkhampa, Dhirawat Jotikasthira, Sutti Malaivijitnond, Piranit Nik Kantaputra
    Abstract:

    Mutations in TBX22 are known causes of cleft palate with/without ankyloglossia. We identified a hemizygous missense c.452G>T (p.Arg151Leu) mutation in a Thai boy who had unilateral complete cleft lip and palate, agenesis of a Maxillary Second Premolar, ankyloglossia, hypoplastic carpal bones, and hypoplastic right thumb. Our study has demonstrated that TBX22 mutation is associated not only with cleft palate and ankyloglossia, but also cleft lip and palate and tooth agenesis. Phenotypic variability caused by a single nucleotide substitution is clearly demonstrated.

Carl J. Andres - One of the best experts on this subject based on the ideXlab platform.

  • Unusual fracture of a Maxillary Second Premolar
    Journal of endodontics, 1995
    Co-Authors: Joseph J. Legan, Cecil E. Brown, Carl J. Andres
    Abstract:

    Root fractures of posterior teeth are rare and occur as a result of severe trauma. This study describes a horizontal root fracture of a Maxillary Second Premolar discovered during routine full-mouth radiographic examination. The tooth was asymptomatic and responded positively to electric pulp testing. The patient had no recollection of a causative event nor was there physical evidence of previous trauma. It is speculated that the fracture was caused when overzealous force was used in seating an overcontoured complete gold crown restoration of an adjacent tooth.

Mustafa Toparli - One of the best experts on this subject based on the ideXlab platform.

  • temperature and thermal stress analysis of a crowned Maxillary Second Premolar tooth using three dimensional finite element method
    Journal of Oral Rehabilitation, 2003
    Co-Authors: Mustafa Toparli, Halil Aykul, Shinya Sasaki
    Abstract:

    The purpose of this study was to calculate the temperature and thermal stress distribution as a result of hot/cold liquid in the mouth. This numerical study was carried out using three-dimensional finite element models and the tooth model was crowned with Au-Pd alloy, Ni-Cr alloy and porcelain. In the first part of the study, temperature changes as a result of hot/cold liquid in the mouth were calculated. In the Second part, the thermal stresses caused by temperature changes were obtained. The tooth was assumed isotropic, homogenous, elastic and unsymmetrical. The authors using fortran 77 prepared all calculation programs. The distribution of temperature and thermal stress were plotted for some critical points.

  • An investigation of temperature and stress distribution on a restored Maxillary Second Premolar tooth using a three-dimensional finite element method.
    Journal of oral rehabilitation, 2000
    Co-Authors: Mustafa Toparli, N. Gökay, T. Aksoy
    Abstract:

    This paper presents the stress analysis of the Maxillary Second Premolar tooth under thermal loading as a result of hot/cold liquid in the mouth using the three-dimensional (3D) finite element method (FEM). The tooth was considered to be in a restored state with composite resin and amalgam on glass-ionomer as the base material. In the first step of the study, the temperature changes as a result of hot/cold liquid in the mouth were calculated. The thermal stress distributions owing to the temperature changes were then obtained. All calculation programs were prepared by the authors using FORTRAN 77. The tooth was assumed to be isotropic, homogeneous, elastic and unsymmetric. The distribution of temperature and stress were plotted for some critical points.

  • Analysis of a restored Maxillary Second Premolar tooth by using three-dimensional finite element method
    Journal of oral rehabilitation, 1999
    Co-Authors: Mustafa Toparli, N. Gökay, T. Aksoy
    Abstract:

    In the first part of this study some physical properties of restorative materials, amalgam, glass-ionomer and composite resin were measured experimentally. In the Second part a numerical study was carried out, for which the Maxillary Second Premolar tooth was used. The tooth model was restored with composite resin and amalgam on glass-ionomer, which was used as the base material. The stress distribution investigated was the resultant of the stresses which come from the mastication force and those resulting from the contraction and expansion of restorative materials. All calculations were carried out using the finite element method and programs were written using FORTRAN 77. A load of 450 N, at an angle of 45 degrees to the longitudinal axis was applied on the occlusal margin of the tooth. The tooth was assumed isotropic, homogenous, elastic and unsymmetrical. The distribution of compressive, tensile and shear stresses were plotted for the whole tooth structure.

T. Aksoy - One of the best experts on this subject based on the ideXlab platform.

  • An investigation of temperature and stress distribution on a restored Maxillary Second Premolar tooth using a three-dimensional finite element method.
    Journal of oral rehabilitation, 2000
    Co-Authors: Mustafa Toparli, N. Gökay, T. Aksoy
    Abstract:

    This paper presents the stress analysis of the Maxillary Second Premolar tooth under thermal loading as a result of hot/cold liquid in the mouth using the three-dimensional (3D) finite element method (FEM). The tooth was considered to be in a restored state with composite resin and amalgam on glass-ionomer as the base material. In the first step of the study, the temperature changes as a result of hot/cold liquid in the mouth were calculated. The thermal stress distributions owing to the temperature changes were then obtained. All calculation programs were prepared by the authors using FORTRAN 77. The tooth was assumed to be isotropic, homogeneous, elastic and unsymmetric. The distribution of temperature and stress were plotted for some critical points.

  • Analysis of a restored Maxillary Second Premolar tooth by using three-dimensional finite element method
    Journal of oral rehabilitation, 1999
    Co-Authors: Mustafa Toparli, N. Gökay, T. Aksoy
    Abstract:

    In the first part of this study some physical properties of restorative materials, amalgam, glass-ionomer and composite resin were measured experimentally. In the Second part a numerical study was carried out, for which the Maxillary Second Premolar tooth was used. The tooth model was restored with composite resin and amalgam on glass-ionomer, which was used as the base material. The stress distribution investigated was the resultant of the stresses which come from the mastication force and those resulting from the contraction and expansion of restorative materials. All calculations were carried out using the finite element method and programs were written using FORTRAN 77. A load of 450 N, at an angle of 45 degrees to the longitudinal axis was applied on the occlusal margin of the tooth. The tooth was assumed isotropic, homogenous, elastic and unsymmetrical. The distribution of compressive, tensile and shear stresses were plotted for the whole tooth structure.