Aging of dental gutta-percha
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Abstract
Gutta-percha is the natural form of trans-1, 4-polyisoprene from trees belonging to the genus Dichopsis. It has been used by dentists for at least 130 years as a compounded mixture of gutta hydrocarbon, zinc oxide, barium sulfate, waxes, resins such as albane, fluavil and coloring agent. However, its physical, mechanical properties have never been elicited until this decade.
In 1967, Dr. Schilder (140) at Boston introduced the warm gutta-percha technique to the dental profession. This technique includes the vertical compaction of warm gutta percha together with a sealer into the entire complesities of the root canal system three dimensionally.
Since the introduction of this modern concept and unique method of accomplishing successful result most predictably, studies on dental gutta-percha concerning its physical properties, mechanical properties, molecular structure, chemistry, composition by improved scientific facilities and investigative capabilities are now in full swing.
With the comprehensive knowledge of the material science, biologic concept, clinical technique and judgement, endodontic care can then be delivered to the public at the highest quality.
This study was attempted toward the investigation of the aging of dental gutta-percha so that a method of storing the dental gutta-percha is formulated. One of the most important characteristics of gutta-percha for commercial purposes is its aging which may be assumed to vary according to conditions of storage and use.
Two primary classes of physical tests were performed on the dental gutta-percha products from different manufacturers namely Mynol, Hygenic, Kerr and Unitek. The first class consists of tests designed to measure 1) the hardness indentation and 2) bending property. The second class is directed toward the determination of the variables or factors possibly affecting the clinical service value of the guttapercha. These storage variables include 1) oxygen, 2) temperature, 3) ultra-violet light and ozone; 4) alcohol, 5) saline and 6) 2.5% of sodium hypochlorite solution.
The results of this study indicates that all the four endodontic gutta-percha specimens behave the similar aging process, Oxygen itself alone, without any other catalysts such as ultra-violet light or heat, will not accelerate the aging effect such as brittleness against bending. However, the specimens stored at 65°c for 3O days, the endodontic gutta-percha cones are brittle and are no longer usable for all clinical purposes. Ultra-violet light acts as a catalyst causing the aging of endodontic gutta-percha. Alcohol and saline apparently help to retard the aging process.
Fresh endodontic gutta-percha shows a modified Brinell Hardness Number of 2.84, and the aged (65°c for 30 days) specimens show 4.97.
This study also demonstrates that dental gutta-percha is an autooxidative substance which is autocatalytic with a induction period of about 20 days when subject to a temperature of 65°c.
Description
Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry. Dept. of Endodontics, 1981.
Includes bibliography: leaves 287-302.
Includes bibliography: leaves 287-302.
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This work is being made available in OpenBU by permission of its author, and is available for research purposes only. All rights are reserved to the author.