THE LOCAL ANESTHETIC EFFECTS ON THE RADIOGRAPHIC RESULTS OF BI-DIGITAL O-RING TEST: A COMPARISON BEFORE AND AFTER INJECTION

Dominic P. Lu D. D. S., F. I. C. A. E.

Professor of Oral Medicine; University of Pennsylvania; School of Dental Medicine, and Director of Medical and Dental Externship Education; Director of Research, Department of Dentistry; Lehigh Valley Hospital/Penn State University Medical School, and President, American Society For Advancement of Anesthesia In Dentistry

Abstract

 The Bi-Digital O-Ring Test (BDORT) can be performed on the radiograph, photograph, MRI or CAT scan, as Dr. Omura demonstrated years ago.  Although the injection in the tissue could, according to Omura, influence the results of the O-Ring Test, there is no research ever done to determine whether injection of local anesthetic may influence the BDORT result on a radiograph. Our research was spurred by two separate episodes at the dental clinic right after BDORT was introduced to the dental students and the resident doctors. In the diagnostic room, pre-operative dental radiographs were taken on two healthy patients seeking emergency treatment due to severe toothache, one with pain on a maxillary 2nd molar and another on a mandibular 1st bicuspid. l.8 cc of local anesthetic (lidocaine hydrochloride 2% with 1:100,000 epinephrine) was administered to both patients. A mandibular block  injection was given to the patient with the bicuspid toothache, and the patient with the maxillary molar toothache was given a supraperiosteal injection at the mucobuccal fold, and a posterior palatine injection was also given. Both patients were taken to the treatment room leaving the radiographs in the diagnostic room for the students to perform the BDORT. The O-Ring was completely open when tested on the radiographs of the offending teeth.

In the treatment room another radiographs were taken by another student inadvertently for the BDORT Without knowing the radiograph already being taken. The test results of the offending teeth on the post-injection radiographs showed different results, namely O-Ring closed. This contradicted the result of BDORT on the pre-injection radiographs. The author was consulted and BDORT was repeated but still with the same results. Consequently, a project to find out the reliability of BDORT on post-injection radiographs and the possible influence of local anesthesia on radiographs was initiated.

METHOD AND MATERIALS:

26 people consisting of resident doctors, nurses, and dental students were grouped into l3 compatible pairs for BDORT.  Radiographs before and after injection were tested. The testers did not know which radiograph was taken before or after injection except the author. The author supervised but did not participate in the test. The results were recorded and analyzed on how many O-Rings were closed, opened, or half opened.

RESULT:

On the pre-injection radiograph of the maxillary molar, 10 pairs had O-Ring open, 1 pair closed, 2 pairs half open, whereas result on post-injection radiograph were: 2 pairs open, 8 fairs closed, 2 pairs half open.

On the mandibular bicuspid case, the BDORT of the pre-injection radiograph results were: 9 pairs open, 2 pairs closed, 2 pairs half open. The post-injection radiograph result were: 7 fairs open, 2 pairs closed, and 4 pairs half open.

 DISCUSSION :

Our BDORT performed before and after injection on the maxillary molar case resulted with sharp contradicting outcome, reflecting the local anesthetic changing the BDORT results. Whereas, in the mandibular bicuspid case the evidence of contrast was not as pronounced. Perhaps the close proximity of supraperiosteal injection at the apex of the maxillary molar plus the more spongiose nature of maxilla made the anesthetic solution more readily absorbed into the maxillary molar area resulted with possible some change in the lesion at the microbiological and/or molecular level. But in the mandibular bicuspid case. the mandibular block injection was done at mid-ramus near the mandibular foramen which is farther away from the target bicuspid area. What role the local anesthetic played in changing BDORT results is a matter of conjecture. It could be lidocaine itself temporarily changed the nature of pathosis. It could be the preservative or the epinephrine or bisulfites contained in local anesthetic to prevent oxidation of epinephrine that had played the role. It has also been hypothesized that during photo taking, photon is transferred from the body to the photograph. Does anesthetic solution affect the way the photons are transferred during photograph taking?

CONCLUSION :

For diagnosis purpose, if BDORT is to be performed on the radiograph, we recommend it should be done before any drug is injected. Our study suggest that the radiograph of the maxillary arch is more sensitive to injectant for BDORT than the mandibular arch. A further research of this phenomenon may be warranted. We are not certain if other patients under the same circumstance will yield the similar results, neither do we know if radiographs of other teeth of the same patient inflicted with different nature of pain or disease would also be affected in the same manner if the same injectant is introduced into the body.