A Case Demonstration of "Deep Shape"

Patient: 45 year-old male in excellent health

Chief Complaint: cold sensitivity on a tooth in the lower right back jaw

Dental History: The patient reported having had a crown placed on the mandibular right second molar (tooth #31) within the last 5 years. Pain developed in the area within the last 2 weeks of the endodontic consultation, specifically sharp lingering pain when the patient drank something cold.

Significant Findings: Sharp, transient sensitivity with the application of a cold or heat stimulus as noted. Slight sensitivity resulted after application of percussive forces and the patient biting on a bite stick. Radiographic findings revealed a “double image” of the mesial root suggesting two separate roots and complex anatomy.

Pulp and Periradicular Diagnosis (tooth #31): Early stage pulp degeneration/ cracked tooth syndrome with acute periradicular periodontitis

Treatment Prognosis (tooth #31): Good

Treatment Plan (tooth #31): Nonsurgical endodontic therapy with exploration for fracture

Special Considerations of Performed Treatment:

Preliminary radiographs should include a bitewing, straight, and off-angles. In this endodontic treatment complex anatomy was anticipated. Access revealed widely separated mesial root orifices consistent with the initial radiographic presentation. When beginning the cleaning and shaping process many numerous
“catches” were encountered with the precurved hand K-files. The coronal flaring was widened to a degree consistent with the root form for each root and numerous recapitulations were employed. Cone fitting was a very belabored process but eventually smooth tug-back was gained in each canal and obturation was completed uneventfully.

The “Deep Shape” which results from employing the Schilder cleaning and shaping technique varies depending upon the root form and complexity of apical anatomy. Patient, gentle, passive placement of files eventually results in a smooth preparation which facilitates proper placement of a precut gutta percha point to the working length. “Standardized” mechanical instrumentation techniques, which try to describe a “cookbook” approach to cleaning and shaping fail to appreciate the unique customized protocol required to address complex apical root anatomy. Terms like “glide path” and “curve management” are borne of the rotary instrumentation where an overly simplistic goal of seeing a white line to the apex on a radiograph is all that is expected. Long-term predictable success with regeneration of the attachment apparatus requires patient, meticulous exploration of all significant internal root space so that the titer of remaining pathogens and potential space communicating with the periradicular environment is eliminated or reduced to non-infective levels, which will not challenge the immune system. Expeditious endodontic treatment may succeed with patients having a hardy host response, but results are less predictable.

The specific characteristics of this root were challenging, especially the distal root which required gradual apical preparation enlargement of a few millimeters back from the working length. Minimal rotary file use was employed as numerous pre curved hand file recapitulations eventually smoothed out the fins, branches, and loops so that placement of a precut gutta percha cone could finally be placed securely with adequate width for sealing.

Key Learning Points:

1. Minimal rotary use and recapitulations with pre curved hand files are required in roots with complex apical anatomy

2. A cone fit with tug-back requires gradual precise root canal preparation with deep shape that serves as a useful indicator suggesting that enough time had been spent in the root with multiple precurved file entries to explore and clear space. More rigid root filling materials (carriers/silver points) or “squirting” allow expeditious demonstration of a “white line to the root apex” on a radiograph but not necessarily proving adequate debridement.

3. Endodontic therapy is predictably successful with a commitment to spend the required time on each unique root presentation.