Clinical case: #3 re-treatment of Thermafil carriers
Presentation Category
Endo
Introduction/Context/Diagnosis
This is a clinical case demonstrating re-treatment of Thermafil carriers on tooth #3 with a metal screw post in the palatal canal. Thermafil obturators were first introduced in the late 1980s and consists of a central carrier, usually plastic, surrounded by a layer of gutta percha. Retreatment of Thermafil carriers can be challenging due to the presence of a plastic carrier that must also be removed to properly re-shape and adequately irrigate the entire root canal system. While gutta percha can be easily dissolved with chloroform, plastic cannot. The technique of braiding Hedstrom files is a commonly used method for removing Thermafil carriers. The H-file possesses a positive rake angle, which allows the file to engage the carrier with more friction and binding strength. The braiding technique involves entwining two to three H-files of sufficient length alongside the carrier followed by a removal attempt.
Methods/Treatment Plan
A 37-year old female patient presented for #3 re-treatment of a root canal performed 3-4 years prior. Patient reported a history of pain, swelling, and intermittent sinus tract. A pre-op PA revealed a metal screw post and an overextended root canal filling in the palatal canal. Pre-op CBCT scan revealed a lateral periapical radiolucency associated with the mesiobuccal and distobuccal root apices. At the time of exam, the patient was diagnosed with #3 previously treated, asymptomatic apical periodontitis.
The metal screw post was removed with an ultrasonically activated tip used in a counter-clockwise direction. Chloroform, ProTaper rotary files, and K-files were used to produce a path through the gutta percha adjacent to the Thermafil carrier to the apical foramen. The braiding technique using multiple Hedstrom files was employed to remove the carriers. Residual gutta percha was wicked out using chloroform and paper points. Standard cleaning and shaping was then performed, followed by warm vertical obturation using gutta percha and AH Plus sealer.
Results/Outcome
The outcome was a successful removal of a metal screw post and three Thermafil carriers followed by obturation with root canal filling of adequate length, density, and taper. The patient was advised to receive a full cuspal coverage restoration following the re-treatment.
Significance/Conclusions
Clinicians should be aware of the challenges that may accompany a re-treatment. Previously treated teeth may contain various root canal fillings including gutta percha, Thermafil carriers, silver points, or pastes such as Russian Red and N2. These cases may also present with iatrogenic errors such as fractured instruments, ledges, perforations, blockages, and transportations. Proper interpretation of radiographs taken at different horizontal angulations may help to identify number of roots and their morphology. CBCT scans may further help identify any missed canals and associated lesions that were obscured by the superimposition of anatomy on 2-dimensional radiographs.
Format
Event
Clinical case: #3 re-treatment of Thermafil carriers
This is a clinical case demonstrating re-treatment of Thermafil carriers on tooth #3 with a metal screw post in the palatal canal. Thermafil obturators were first introduced in the late 1980s and consists of a central carrier, usually plastic, surrounded by a layer of gutta percha. Retreatment of Thermafil carriers can be challenging due to the presence of a plastic carrier that must also be removed to properly re-shape and adequately irrigate the entire root canal system. While gutta percha can be easily dissolved with chloroform, plastic cannot. The technique of braiding Hedstrom files is a commonly used method for removing Thermafil carriers. The H-file possesses a positive rake angle, which allows the file to engage the carrier with more friction and binding strength. The braiding technique involves entwining two to three H-files of sufficient length alongside the carrier followed by a removal attempt.
