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Inside Dentistry

July/August 2006, Volume 2, Issue 6
Published by AEGIS Communications


Endodontic Leakage Resistance of Fiber Obturators

Howard E. Strassler, DMD

Kurtzman G, von Fraunhofer J, Oliveira DP. J Dent Res (Special Issue A). 2006;85. Abstract No. 1443.

Abstract
Objectives: Fiber obturators have been introduced into endodontics but there are few reports of their efficacy. This study evaluates fiber obturator resistance to endodontic leaks compared with other obturation materials. Methods: Sixty-four human single rooted teeth, with 20-mm average working length, were used. Access was prepared coronally and patency confirmed with a hand file. The canals were instrumented to apical size ISO #40 with NaOCl irrigation, paper point dried, 17% EDTA rinsed, re-dried and divided into eight groups of N = 8. They were obturated as follows: (1) InnoEndo fiber obturator with InnoEndo adhesive and resin sealer, (2) InnoEndo fiber obturator with a self-adhesive resin sealer, (3) Fibrefill fiber obturator with Fibrefill adhesive and resin sealer, (4) GP with Endorez resin sealer, (5) Endorez cone with Endorez resin sealer, (6) Resilon cone with Endorez resin sealer, (7) GP with ZOE sealer and (8) GP with AH26 sealer. PVC covered copper wire was placed coronally into each tooth in contact with the obturation material and sealed in place. The teeth were immersed in 0.9% NaCl solution together with a stainless steel counter electrode. A 20V DC voltage was connected between the stainless steel and each tooth in turn, and current flow determined by voltage drop across a standard resistor (100 Ω) in the circuit. Current flow in the circuit was observed for 30 days and ANOVA and Scheff Ω testing used to compare and identify any statistically significant differences in the leakage behavior. Results: All specimens showed a progressive increase in leakage with time. The specimen leakage fell into two groups; the least was found with obturations 1, 2, 3 and 5, the greatest with obturations 4 and 8, with obturations 6 and 7 being intermediate. Conclusions: The data indicate that fiber obturation and a new cone/sealer system provide the best canal obturation.

COMMENTARY

Coronal leakage has been identified as a factor in endodontic failure. With the loss of coronal seal, bacteria can penetrate between the restoration and tooth to inevitably reach the endodontic filling. In most cases the evidence of coronal leakage is not readily apparent until the caries or loss of the restoration occurs. This study provides insight into how using novel adhesive systems can improve leakage resistance. The researchers in this in vitro study compared the InnoEndo fiber-adhesive obturator system to conventional root canal filling with gutta percha with both AH26 and zinc oxide and eugenol sealers. Other research has investigated and compared conventional root canal filling systems. The results of this study demonstrated that the use of an adhesive type of fiber oburation and new cone/sealer system provided the best obturation. It is expected that when coronal leakage occurs that using an adhesive system such as these that have been investigated will better protect the root canal filling and minimize risk of endodontic failure.

Leakage both coronally and apically around a root canal filling has been a controversial topic in determining the relationship between leakage and endodontic failure. While leakage is considered to be a significant factor, the clinician must perform a thorough evaluation and consider not only leakage but also the length of time the endodontic filling has been exposed to the oral environment, the radiographic quality of the endodontic treatment, the presence or absence of periapical pathology, the quality of the coronal restoration, and the presence or absence of symptoms.

About the Author

Howard E. Strassler, DMD
Professor and Director of Operative Dentistry
Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School, Baltimore, Maryland
Email: hstrassler@umaryland.edu


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