Dentists should know current evidence-based success rates of the treatment they are recommending for the patient to respond to patients’ questions. There have been a number of meta-analyses and systematic reviews in the literature comparing long-term endodontically treated tooth and implant survival rates that can assist the dental practitioner in making decisions (Levin and Halperin-Sternfeld 2013; Torabinejad et al. 2007; Tomasi et al. 2008; Holm-Pedersen et al. 2007; Jung et al. 2012). Endodontic success rates on teeth without periapical pathology have been reported to be 92–98 % but range from 73 to 90 % with periapical lesions that heal following RCT (Torabinejad et al. 2005 ). When considering endodontic re-treatment and apical surgery, the success rates are even lower and range from 74 to 86 % and 37 to 74 % (Ng et al. 2010, 2011; Gulabivala, Iceland, Freedman, AAC Dallas, 2005) Reviews of trials and studies on the success of implant single crowns range from 57.5 to 100 % (Papaspyridakos et al. 2012). A recent review from the Journal of the American Dental Association (2013) concluded that implant survival rates do not exceed the rates of adequately treated and maintained compromised teeth. (This supports the concept that extracting a tooth and placing an implant should be made based on patient-specific factors and the prognosis of the tooth.) The practical implication from the review was that even though a compromised tooth may require additional treatment for maintenance, implant treatment may also require adjunctive treatment or subsequent revisions from later complications that would pose additional risks. Tooth extraction and replacement may be done at anytime in the treatment and should be carefully considered since it is irreversible.

Other meta-analysis reviews have been performed that compare treatment outcomes of compromised teeth. One systematic review (Torabinejad et al. 2007) concluded that both root canal treatment with a restoration and implant-supported single crowns had higher long-term survival rates as compared to fixed partial dental prosthesis. Additionally, the research stated that extraction without replacement had poorer psychosocial outcomes as compared to the alternative treatment offered. Another systematic review found difficulty in making comparisons between RCT and implant treatment due to the heterogeneity in the findings (Tomasi et al. 2008). A systematic review comparing natural untreated teeth, compromised treated natural teeth, and implant treatment concluded that “oral implants when evaluated after 10 years of service do not surpass the longevity of even compromised but successful root canaltreated natural teeth” (Holm-Pedersen et al. 2007).

It is important when reviewing evidence for treatment recommendations that the reader ensures that the authors of the reviews make similar comparisons. Much of the implant literature considers survival rates in reporting outcomes, and the endodontic literature reports statistics in terms of success and survival (Norton 2001; Gotfredsen 2004; Gibbard and Zarb 2002; Morris et al. 2001). Only recently have reviews been conducted to evaluate criteria for implant success (Papaspyridakos et al. 2012) to include evaluating the “long-term primary outcome of the implant prosthetic complex as a whole” (p 247 Papaspyridakos). Survival rates will typically be higher than success rates. So when these meta-analyses are compared, the studies that are used need to be comparable, and survival levels are used since very few implant studies report success rates.

Root canal therapy and implant placement are “complementary treatment options for the appropriate patient situation” (Doyle, p. 2, 2015). There can be many complicating factors depending on the patient that need to be considered in each case. But simply stated, root canal treatment should be the primary consideration in general for restorable, periodontally healthy teeth that have irreversible pulpitis and/or periapical periodontitis (Doyle 2015; Iqbal and Kim 2008; Zitzmann et al. 2009). Implant placement should be considered in general for nonrestorable teeth and/or teeth with severe periodontal unhealthy conditions. To preserve the endodontically treated tooth successfully, there must be enough sound tooth structure to place a core or a post and core and to have an adequate ferrule for the crown margin of 2 mm surrounding the natural sound tooth structure (Sorensen and Engelman 1990; Libman and Nicholls 1995; Isidor et al. 1999). This situation would make the tooth clinically restorable. The presence of multiple risk factors though can jeopardize the compromised tooth and may weigh the decision toward extraction and implant placement or maintain the decision for RCT and final restoration. These other risk factors that must be considered include outcomes assessment, systemic conditions, tooth and periodontium factors, and patient-specific considerations (Torabinejad and Goodacre 2006; Salinas and Eckert 2007; Torabinejad et al. 2014).

Studies analyzing outcomes of RCT and ISC can be conflicting (Stockhausen et al. 2011), yet patients want to know whether a procedure that is recommended will be successful. It has been recommended that guidelines be in place so that these decisions can be made by the dentist to appropriately inform the patient. While both RCT and ISC have been found to be successful, studies predicting long-term outcomes concerning RCT have traditionally used “success and failure” as outcomes measures, while implant studies have used survival as outcome measures, making direct comparisons challenging. Long-term survival levels are comparable for both treatments. However, other factors must be taken into consideration.