Determination of Double Bond Conversion in Dental Resins by Near Infrared Spectroscopy

Published

January 1, 2001

Author(s)

J W. Stansbury, Sabine H. Dickens

Abstract

Objectives: This study determined the validity and practicality of near infrared (NIR) spectroscopic techniques for measurement of conversion in dental resins. Methods: Conversion measurements by NIR and mid-IR was compared using two techniques: (1)The conversion of 3 mm thick photopolymerized Bis-GMA/TEGDMA resin specimens was determined by transmission NIR. Specimens were then ground and reanalyzed in KBr pellet form by mid-IR. (2) As further verification, thin resin films were photocured and analyzed by mid-IR. Multiple thin films were then compressed into a thick pellet for examination by NIR.Results: Conversion values obtained by NIR and mid-IR techniques did not differ significantly. A correction for changing specimen thickness due to polymerization shrinkage was applied to NIR conversion measurements since an internal standard reference peak was not employed. Sensitivity of the NIR technique was superior to those based on the mid-IR.Significance: The nondestructive analysis of conversion in dental resins by NIR offers advantages of convenience, practical specimen dimensions and precision compared with standard mid-IR analytical procedures. Because glass is virtually transparent in the NIR spectrum, this technique has excellent potential for use with filled dental resins as well.

Citation

Dental Materials Congress

Volume

17

Issue

No. 1

Pub Type

Journals

Keywords

conversion, dental materials, methacrylate monomers, near infrared, resins, spectroscopy

Citation

Stansbury, J. and Dickens, S. (2001), Determination of Double Bond Conversion in Dental Resins by Near Infrared Spectroscopy, Dental Materials Congress (Accessed October 22, 2025)