Oral Health Group

Success for the Best, Survival for the Rest

May 1, 2014
by Joel Fransen, BSc(OT), DMD

Should a tooth be saved or should it be extracted and an implant placed? Is basing a comparison between implant retention and RCT success on endodontic outcome measures reliable? The short answer is no. Strindberg’s criteria (1956) and the PAI index (Ørstavik et al., 1996) are widely accepted as measures of RCT success. Generally, RCT success criteria are stricter than those for implant survival. Although more standardized than implant literature, below is a list of some concerns about RCT outcome studies:

• In many studies, pre-doctoral students performed the RCT,


• Follow-ups were often too short for full healing of a lesion to occur (i.e. 6 months),

• Minimal to no exclusion criteria,

• Almost no control of type or timing of the final restoration.

Pre-doctoral students lack experience and may not accurately represent the skills of the average practicing dentist. Healing of a lesion of endodontic origin can take well over five years. Thus, many healing teeth would not qualify as successful for the purposes of a typical study. Unlike most implant studies, there were few or no exclusion criteria for potential patients. The timing and quality of the final coronal restoration is the single most important factor in the retention of a RCT tooth; this too was rarely controlled. Advances in endodontic procedures, such as instrumentation, irrigation, illumination, and magnification, make it unreliable to rely on outcome studies from more than ten years ago. To do so would be analogous to relying on survival rates of blade implants for modern osseointegrating implants.

In the literature, resolution of apical periodontitis and asymptomatic responses are necessary for endodontic success. Most implant studies assess survival, not success. Implant survival requires osseointegration regardless of the presence of peri-implantitis or bone loss. Thus, ailing, failing, or non-restorable implants would still qualify as survived. Below is a list of how most traditional implant studies differ from typical endodontic success studies:

• Most implants placed by specialists,

• Exclusion of smokers, bruxers/clenchers/other para-functions, regular alcohol consumers, poor hygiene, uncontrolled diabetes, those with class IV bone, etc.

• Failures within the first year were not part of the inclusion criteria,

• Non-restorable implants, nerve damage, abandoned surgeries, poor aesthetics, and other complications did not exclude implants from survival status.

Promoting implant survival rates of >95 percent is improper as the results are based on ideal situations. It is unfair to expect private practice dentists working on the public to mimic such high survival rates. A patient may not be impressed if their implant has survived but is non-restorable, unaesthetic, has peri-implantitis, or significant bone loss. Doyle et al., 2006 used success criteria for both implants and RCT teeth and followed the patients for seven to nine years; the success rate for implants was 74 percent and 84 percent for RCT teeth.

At best, comparing survival and success rates is problematic and it can be an obstacle to maintaining the long-term oral health to the public. The decision to save or extract a tooth must be based on the clinical parameters of the individual patient. So here is to your success in 2014, as survival alone is not enough! OH

Dr. Fransen received his DMD from the University of British Columbia and his certificate in Endodontics from the Baylor School of Dentistry, Texas A&M Health Sciences Center. Dr. Fransen has lectured both in the United States and Canada. He practices the full scope of modern endodontics including differential diagnosis, revascularisation and vital pulp therapy, non-surgical treatment and re-treatment, and endodontic microsurgery.

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