Method and device for determining viability of intact teeth

US4836206A · kind A · utility

Assignee

• The United States of America, as represented by the Department of Health and Human Services · US

Inventors

• G. Maret Maxwell · Silver Spring, US
• Richard L. Webber · Winston-Salem, US

Key dates

• Filing date: Feb 25, 1987
• Grant date: Jun 6, 1989
• Expiry date: Feb 25, 2007

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61B2562/0238
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

An optical technique and device for assessing tooth vitality, involving the use of trans-illumination to detect differentially the relative absence of light absorbed by hemoglobin in circulating blood inside a healthy tooth. White light received from an illuminated healthy tooth is relatively devoid of intensity at a wavelength characteristic of absorption by hemoglobin, when compared with light following the same path in the tooth but of a longer wavelength, by taking the ratio of intensities of the two wavelengths the light of one wavelength is relatively more absorbed by hemoglobin or oxyhemoglobin than the other, indicating the relative amount of blood or oxygen in the blood present in the tooth at the time of the measurement. A broad-spectrum light source is rigidly coupled to a split-beam, differentially-filtered photometer incorporating relatively narrow band filters. Vitality is assessed from the ratio of the scattered light at the two wavelengths, and in change of this ratio overtime.