Preserving the natural tooth versus extraction and implant placement: An evidence-based approach

Abstract

Both dental implants and endodontically treated teeth have demonstrated favorable outcome rates. However, there is still controversy regarding when to extract in favor of an implant and when to keep a natural tooth. Much of this controversy stems from the way the outcome of dental implants is defined. A majority of implant studies have used the measure of “survival” instead of “success." Survival rates up to 95.5 % after 1 year of follow-up have been reported. By contrast, most endodontic studies have applied strict success criteria, in particular requiring the resolution of apical periodontitis and the absence of symptoms. This renders a direct comparison to implant survival studies obsolete. If survival studies are compared, there is no significant difference in outcome between restored single-unit implants (95 %) and endodontically treated teeth (94 %) over 6 years. When it comes to tooth preservation, there are several factors to consider beyond the endodontic aspects. A favorable periodontal status and sufficient remaining internal and external tooth structure are needed to allow for tooth preservation. Key to restorability are an acceptable crown-to- root ratio and sufficient supra-osseous tooth structure with adequate biological width and ferrule. Crown lengthening and orthodontic extrusion are adjunctive procedures that may provide for additional supra-crestal hard tissue structure if necessary. When all these factors are properly addressed, restorations on teeth have a good long-term prognosis. However, keeping a natural tooth must fit in the overall treatment plan for the patient. Restorations on implant fixtures, on the other hand, have lower life expectancies over 5-10 years than the implant itself, and biological, technical, or esthetic complications have frequently been reported. At 10 years and in long-term studies >>15 years, natural teeth were shown to exceed the life expectancy of implants, including endodontically treated or periodontally compromised teeth. However, keeping a natural tooth must fit in the overall treatment plan for the patient. Recently, attention in implant dentistry has been drawn to marginal gingivitis, periimplantitis, and long-term esthetic problems. Thus, the focus has shifted away from prematurely extracting teeth, knowing that reimplantations in previous implant locations are more demanding if an implant is failing or has been lost. Priority should be aimed at preserving the natural dentition, and implants should replace only missing or non-restorable teeth but not teeth per se.