نام کاربری :
رمز عبور :
  به خاطر بسپار
کلمه عبور را فراموش کرده ايد؟
ثبت نام کاربر جديد
AWT IMAGE

AWT IMAGE
ترمیمی: The slippery slope - critical perspectives on in vitro research methodologies

The slippery slope - critical perspectives on in vitro research methodologies

Abstract

Objectives

This paper attempts to provide critical perspectives on common in vitro research methodologies, including shear bond testing, wear testing, and load-to-failure tests. Origins of interest in high-quality laboratory data is reviewed, in vitro data is categorized into property and simulation protocols, and two approaches are suggested for establishing clinical validity. It is hoped that these insights will encourage further progress toward development of in vitro tests that are validated against clinical performance and/or by producing clinically validated failure or damage mechanisms.

Materials and methods

Published shear and tensile bond data (macro and micro) is examined in light of published finite element analyses (FEA). This data is subjected to a Weibull scaling analysis to ascertain whether scaling is consistent with failure from the bonded interface or not. Wear tests results are presented in light of the damage mechanism(s) operating. Quantitative wear data is re-examined as being dependent upon contact pressure. Load-to-failure test results are re-analyzed by calculating contact stresses at failure for 119 tests from 54 publications over more than 25 years.

Results

FEA analyses and reported failure modes (adhesive, mixed, cohesive) are consistent with failure not involving interfacial “shear stresses” as calculated in published work. Weibull scaling clearly suggests failure involving external surfaces of specimens, not interfacial origins. Contact stresses (pressures) are clearly an important variable in wear testing and are not well-controlled in published work. Load-to-failure tests create damage not seen clinically due to excessively high contact stresses. Most contact stresses in the 119 tests examined were calculated to be between 1000 MPa and 5000 MPa, whereas clinical contact stresses at wear facets have been measured not to exceed 40 MPa.

Conclusions

Our community can do a much better job of designing in vitro tests that more closely simulate clinical conditions, especially when contact is involved. Journals are encouraged to thoughtfully consider a ban on publishing papers using bond tests and load-to-failure methods that are seriously flawed and have no clinical relevance.


Source: Dental Materials

Full text

بایگانی مطالب:

Standardizing failure,success, and survival decisions in clinical studies of ceramic and mental-ceramic fixed dental prostheses
Longevity of posterior composite restorations: Not only a matter of materials
Durability of bones and clinical success od adhesive restoration
Correlation Of Cilnical performance with 'in vitro tests' of restorative dental materials that use polymer-based materics
The slippery slope - critical perspectives on in vitro research methodologies
Dimethacrylate network formation and polymer property evolution as determined by the selection of monomers and curing conditions
The future of dental devices is digital
Predicting clinical biological response to dental materials
Effect of Resin Cement System and Root Region on the Push-out Bond Strength of a Translucent Fiber Post
Loading Standardization of Postendodontic Restorations In Vitro: Impact of Restorative Stage, Static Loading, and Dynamic Loading
Influence of the Curing Mode on Fluoride Ion Release of Self-adhesive Resin Luting Cements in Water or During pH-Cycling Regimen
Effect of Prewarming and/or Delayed Light Activation on Resin-Modified Glass Ionomer Bond Strength to Tooth Structures
Long-Term Nanoleakage Depth and Pattern of Cervical Restorations Bonded With Different Adhesives
Cross-Compatibility of Methacrylate-Based Resin Composites and Etch-and-Rinse One-Bottle Adhesives
Reparability of Aged Silorane With Methacrylate-Based Resin Composite: Micro-Shear Bond Strength and Scanning Electron Microscopy Evaluation
Proximal Marginal Overhang of Composite Restorations in Relation to Placement Technique of Separation Rings
Data Comparison Between Two Dental Spectrophotometers
Randomized Clinical Trial of Four Adhesion Strategies: 18-Month Results
Treatment of Invasive Cervical Resorption With Sandwich Technique Using Mineral Trioxide Aggregate: A Case Report
The Tucker Technique: Conservative Molar Inlays Preserving the Transverse Ridge

مطالب کدام بخش سایت بیشتر مورد نیاز شماست؟
پرسش و پاسخ
جشنواره شهید هدایت
کلینیک تخصصی دندانپزشکی
مجله علمی
نمایشگاه کتاب
نمایشگاه مواد و تجهیزات دندانپزشکی
نیازمندیها
   
:. کل کاربران ثبت شده: 168
:. کاربران حاضر در وبگاه: 0
:. میهمانان در حال بازدید: 10
:. تمام بازدید‌ها: 7955259
:. بازدید 24 ساعت قبل: 3073

کلیه حقوق این وب سایت متعلق به جامعه اسلامی دندانپزشکان می باشد.

صفحه اصلی | درباره ما | ارتباط با ما | نقشه سایت

Created in : 0.64 seconds with 46 queries by YEKTAWEB