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Title Gutta-Percha on a Plastic or Metal Carrier Lowers Success of Post Space Preparation
Clinical Question In patients needing a post space preparation for post and core restoration, is removal of condensed gutta percha more successful than removal of gutta percha on a plastic or metal carrier (ex. Thermafil)?
Clinical Bottom Line Removal of gutta percha on a plastic carrier for post space preparation is associated with a higher incidence of deviation from root canal preparation as well as a compromised apical seal vs. removal of vertically or laterally condensed gutta percha.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 7996083Ricci/1994110 extracted teethLaboratory study
Key resultsThree groups of 10 teeth were obturated with lateral condensation, Thermafil on a plastic carrier, or Thermafil on a metal carrier respectively; 20 additional teeth served as a control group. Post space preparation was accomplished with a Peeso reamer, a Prepi bur (Tulsa Dental Products) made for removal of Thermafil on a plastic carrier, and by notching the metal carrier with a #1558 fissure bur at the desired 4 mm level prior to Thermafil placement for groups 1, 2 and 3 respectively. Gutta percha on a plastic carrier showed an average 4.36 mm die penetration vs. 1.55 mm for laterally condensed gutta-percha and 1.24 mm for gutta percha on a metal carrier.
#2) 26865499Schroeder/201642 extracted teethLaboratory study
Key resultsThree groups of 14 teeth each were obturated with gutta percha and warm vertical compaction, Thermafil on a plastic carrier, and GuttaCore respectively. Post space preparation was accomplished with a GT Post Drill for all groups. Deviation from root canal preparation occurred in 50% of teeth obturated with gutta-percha on a plastic carrier vs 1% of teeth obturated with GuttaCore and 0% of teeth obturated with gutta percha by warm vertical condensation.
Evidence Search post[All Fields] AND space[All Fields] AND preparation[All Fields] AND thermafil[All Fields]
Comments on
The Evidence
It must be noted that both pieces of evidence provided are laboratory studies and thus low on the evidence pyramid. However, considering that our question concentrates more on the physics of post placement in endodontically treated teeth with gutta-percha on a carrier rather than the clinical aspects or biological properties, laboratory studies are expected. For both pieces of evidence, adequate sample sizes are used, and in Ricci et al., experimental groups are compared to positive and negative controls to eliminate confounding variables. Methods of measurement were thoroughly explained and data was provided with comments on statistical significance. Unexpected results in Ricci et al. showed gutta percha on a metal carrier to have less leakage compared with lateral condensation, which the authors hypothesized was due to the different techniques used for post space preparation and the sticking of the bur to the melted plastic carrier as the bur was removed. However, if post space preparation is not initially intended following endodontic treatment and the metal carrier is not pre-notched, one can expect removal of gutta percha to be more difficult and likely to cause more apical leakage to occur. Additionally, from the data in Schroeder et al. it appears GuttaCore is equal to warm compacted gutta percha in ease of removal; however, a conclusion on effectiveness of GuttaCore for obturation during endodontic treatment is not addressed. The evidence presented herein is important not only when considering post placement in endodontically treated teeth obturated with gutta percha on a plastic or metal carrier, but also when choosing a material for obturation during endodontic treatment. Ultimately, this evidence influences our choice of materials when treatment planning by providing us with a proven prognosis.
Applicability It is not uncommon for a dentist or dental student to encounter a previously endodontically treated tooth that has been obturated with gutta percha on a plastic or metal carrier such as Thermafil. Unfortunately, it is nearly impossible to differentiate these teeth clinically or radiographically. Therefore, it can come as a surprise to a dentist placing a post to realize that a plastic or metal carrier exists within the gutta percha. Worse, the presence of a a plastic or metal carrier may not be realized, consequently resulting in deviation during post space preparation and possibly root perforation. If existence of a plastic or metal carrier is realized, the dentist may decide to attempt removal regardless of the unexpected finding due to time constraints or a lack of knowledge of the potential hazards. However, armed with the evidence presented above, one is prepared with the knowledge that proceeding to remove gutta percha on a carrier as if it were gutta percha lacking a carrier has a poor prognosis. Additionally, one can discuss this information with the patient to decide if preserving the tooth is still the preferred treatment considering the new risks vs. tooth removal followed by implant placement and prosthetic restoration. If a decision is made to preserve and restore the existing tooth, one can proceed with caution using the Prepi bur or the notching techniques, as described by the manufacturer, or refer the patient to an endodontist.
Specialty/Discipline (Endodontics) (General Dentistry) (Prosthodontics) (Restorative Dentistry)
Keywords Thermafil, post space preparation, endodontically treated teeth, root perforation
ID# 3232
Date of submission: 05/18/2017spacer
E-mail hermannrh@livemail.uthscsa.edu
Author Robert Hermann
Co-author(s) e-mail
Faculty mentor/Co-author David Cox, DDS and Daniel Lavin, DDS
Faculty mentor/Co-author e-mail CoxD@uthscsa.edu; LavinD@uthscsa.edu
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