September 7, 2005
Referring Doctors > Information Letters
Update on Practical Endodontic Research
Once again,we would like to keep you informed of some of the latest developments in endodontics. A very interesting study was conducted to help us understand the distance to drill to reach the pulp chamber in bicuspids and molars. Extensive measurements were recorded by using a digital imaging system and x-ray equipment. The results showed that on average the distance from the cusp tip to the pulp chamber ceiling is 7.0 mm +/- 0.5mm in both bicuspids and molars. The distance from the pulp chamber floor to the furcation is 1.85mm +/- 0.85mm. The average pulp chamber height is 2.76mm +/- 0.97mm.(1) Essential Dental Laboratories has come out with a high speed drill with a stop set at 7.0mm to help prevent perforation.
A dog study was done comparing in vivo the periapical inflammatory reaction to filling the root canal with AH26 sealer versus Resilon material with Epiphany primer and sealer. At 14 weeks mild inflammation was seen in 82% of the roots filled with gutta-percha and AH26. Only 19% of the roots filled with Resilon/Epiphany material showed mild inflammation.(2) The conclusion proposed was that "the Resilon 'monoblock' system was associated with less apical periodontitis, which may be because of its superior resistance to coronal leakage." Even though dog studies are not as good as human ones, these results are interesting.
In another study, eighty single-canal extracted teeth were instrumented to a #40 file at
the working length. When teeth were prepped, they were randomly separated into five groups and filled as followed: 1) lateral and 2) vertical condensation with gutta-percha 3) lateral and 4) vertical condensation with Resilon; and 5) a control group with no filling material. The teeth were stored at 100% humidity for 2 weeks. They were individually mounted on a stabilizing base and subjected to increasing compression forces until they fractured. The results of this study showed significant resistance to tooth fracture of Resilon filled teeth compared to the ones filled with gutta-percha, regardless of the filling technique. (3) This information is a follow up to one of our prior newsletter claims about Resilon.
A study was done to test the sealing ability of various root-end filling materials. MTA, SuperEBA and Vitremer were tested. MTA presented the best results.(4)
Another study was done to determine the incidence of two canals in mesiobuccal
roots of permanent maxillary molars and mesial roots of permanent mandibular molars. Over 40 roots in each category were studied. Transverse 1mm-thick cross sections at 2,3,4, and 5mm from the apex were obtained , stained and examined using a stereomicroscope. Two canals were found in 80.8% of the maxillary MB roots and 95.2% in the mandibular mesial roots.(5) These percentages are greater than one would expect, especially in maxillary molar mesiobuccal roots.
As always, if you would like to discuss any of these, or other topics, please call us any time.
(1) A. Deutsch, et.al "Morphological Measurements of Anterior Landmarks in Pulp Chambers of Human Maxillary Furcated Bicuspids." J.O.E.: Vol. 13 (8) August 2005, PP. 570-573
(2) Shipper, et al., "Periapical Inflammation of the Coronal Microorbital Inoculation of the dog tooth filled with gutta-percha or Resilon." J.O.E. 31 (2) : 91-96, February 2005
(3) F. Teixeira, et.al. "Fracture Resistance of Endodontically Treated Roots Using a New Type of Material." JADA 2004; 135:646-652
(4) C.Xavier, et.al. "Root-End Filling Materials; Apical Microleakage and Marginal
Adaptation." J.O.E. Vol.31 (7); pp. 539-542, July 2005
(5) I. Jung, et.al. "Apical Anatomy in Mesial and Mesio-buccal Roots of Permanent
First Molars." J.O.E. Vol. 31(5): 364-368, May 2005