JOE jan 2013 - Detection of Dentinal Microcracks Using Infrared Thermography

Detection of Dentinal Microcracks Using Infrared
Thermography
Manami Matsushita-Tokugawa, DDS, PhD,* Jiro Miura, DDS, PhD,‡ Yukiteru Iwami, DDS, PhD,* Takahide Sakagami, PhD,§ Yui Izumi, PhD,k Naoya Mori, BA,¶ Mikako Hayashi, DDS, PhD,* Satoshi Imazato, DDS, PhD,† Fumio Takeshige, DDS, PhD,‡ and Shigeyuki Ebisu, DDS, PhD*

Abstract

Introduction: 

It is difficult to make a definite diagnosis of a cracked tooth solely based on an inspection within the root canal, especially in case of microcracks. At present, there seems to be no established method to detect dentinal microcracks in roots; therefore, the current detection techniques need to be improved. Vi- brothermography (VibroIR) helps to detect microcracks by the friction heat generated from ultrasonic vibration. The purpose of this study was to establish a novel method using VibroIR to detect dentinal micro cracks. 

Methods: 

The root canals of 20 roots with cracks and control roots were prepared after removing the tooth crowns. A tapered indenter was inserted into the root canal and pressed until a microcrack was created under an optical microscope. Using VibroIR, the detection trials for dentinal microcracks were performed with an ultra- sonic vibration power ranging from 0.43 to 1.48 W at an angle of 0 , 30 , 45 , 60 , and 90 between the ultrasonic vibration point and the microcrack line. After the detection test, the microcrack width was measured with an optical microscope. 

Results: 

Frictional heat was detected in the microcracks with thermography at 0.89 to 1.48 W and at an ultrasonic vibration point angle less than 60 from the crack line for 10 seconds. Micro- cracks with a width of 4 to 35.5 mm were detected with this method. 

Conclusions: VibroIR may be an effective method for the diagnosis of root dentinal micro cracks. 

(J Endod 2013;39:88–91)