Experimental Parameter Estimation Method for Nonlinear Viscoelastic Composite Material Models: An Application on Arterial Tissue

This study is aimed at setting a method of experimental parameter estimation for large-deforming nonlinear viscoelastic continuous fibre-reinforced composite material model. Specifically, arterial tissue was investigated during experimental research and parameter estimation studies, due to medical, scientific and socio-economic importance of soft tissue research. Using analytical formulations for specimens under combined inflation/extension/torsion on thick-walled cylindrical tubes, in vitro experiments were carried out with fresh sheep arterial segments, and parameter estimation procedures were carried out on experimental data. Model restrictions were pointed out using outcomes from parameter estimation. Needs for further studies that can be developed are discussed

The influence of implant number and attachment type on maximum bite force of mandibular overdentures: a retrospective study

Aim: Assessment of the influence of such factors as attachment type, number of implants, gender and age of patients on maximum bite force (MBF)

The impact of frenulum height on strains in maxillary denture bases

PURPOSE. The midline fracture of maxillary complete dentures is a frequently encountered complication. The purpose of this study was to assess the effect of frenulum height on midline strains of maxillary complete dentures. MATERIALS AND METHODS. A removable maxillary complete denture was fabricated and duplicated seven times. Four different labial frenulum heights were tested for stresses occurring on the palatal cameo surface. The strains were measured with strain gauges placed on 5 different locations and the stresses were calculated. To mimic occlusal forces bilaterally 100 N of load was applied from the premolar and molar region. RESULTS. A statistically significant association between the height of the labial frenulum and the calculated stresses and strains was shown (P<.05) predominantly on the midline and especially on the incisive papilla. The results showed that stress on the anterior midline of the maxillary complete denture increases with a higher labial frenulum. CONCLUSION. Within the limitations of this in vitro study, it can be concluded that the stress on the anterior midline of the maxillary complete denture increases with a higher labial frenulum. Surgical or mechanical precautions should be taken to prevent short-term failure of maxillary complete dentures due to stress concentration and low cycle fatigue tendency at the labial frenulum region

Effects of caffeic acid phenethyl ester and melatonin on distraction osteogenesis: an experimental study

Aim: The aim of this experimental animal model study is to investigate the effects of caffeic acid phenethyl ester (CAPE) and melatonin on the maturation of newly-formed regenerated bone in distraction osteogenesis

Evaluation of two interforaminal implants and implant-assisted removable dentures on stress distribution: an in vitro study

Objectives: In mandibular edentulism, the treatment option with a two-interforaminal implant-retained bridge and a removable partial denture is rarely evaluated in literature. The aim of this in vitro study was to evaluate the stress distribution of this treatment option by comparing it with traditional treatment options with interforaminal implants in the edentulous mandible

Biomechanical analysis of multilevel discectomy and excision of posterior longitudinal ligament: An in vitro study in sheep

Aim: This experimental biomechanical study was performed to determine the effects of multilevel anterior cervical discectomy and excision of posterior longitudinal ligament (PLL) to stabilize the cervical spine using an in vitro animal model. Materials and Methods: Fifty fresh cadaveric C3-C6 sheep spine specimens were divided into five experimental groups: Group A was the control group; Group B, one-level discectomy; Group C, two-level discectomy, Group D, three-level discectomy, and Group E, three-level discectomy and excision of PLL, respectively. The specimens were subjected to non-destructive loads cycled from zero to five Newton-meter for flexion, extension, right and left lateral bending, and axial rotation on an electrohydraulic test machine. Load displacement curves were obtained via collected data using strain gauges. The values were obtained for all five groups, statistical differences were determined respectively (P 0.05). Conclusion: Our data suggested that cervical discectomy decreases stability of sheep spine pieces

The Influence of the Attachment Type and Implant Number Supporting Mandibular Overdentures on Stress Distribution: An In Vitro Study, Part I

Objectives: The main goal of this study was to compare the stress distribution of mandibular overdentures (OVD) with different numbers of supporting implants and single versus splinted attachment types

Biomechanical comparison of oblique and step-cut osteotomies used in total hip arthroplasty with femoral shortening

Background: Various types of shortening osteotomies and prosthesis are used for femoral reconstruction in total hip arthroplasty of the high hip dislocation. This biomechanical study investigates whether step-cut osteotomies result in better stability than oblique osteotomies and cylindrical femoral stems enhance stability of the osteotomy more than conical stems, and which osteotomy and prosthesis type maintain the stability better after cyclical loading

The Effect of Strut Allograft and Its Position on Vancouver Type B1 Periprosthetic Femoral Fractures: A Biomechanical Study

The aim of this study is to assess the biomechanical advantage of adding strut allograft and the effect of its position on the construct in Vancouver type B1 fractures. Fifteen forth-generation synthetic femurs were used and created a fracture model at the tip of prosthesis, and subsequently fixated with a lateral plate only, lateral plate and medial strut, lateral plate and anterior strut. Rotational and axial tests were performed. In all loading tests, the plate with medial strut group was stiffer than the other constructs and had higher failure load values and had less displacement in the fracture site. A combination of a plate with a medial strut allograft provides more mechanical stability on periprosthetic femoral fractures near the tip of a total hip arthroplasty. (C) 2014 Elsevier Inc. All rights reserved