The following report describes the proceedings of theToronto Symposium, April 24 and 25, 1998, held at theUniversity of Toronto, Ontario, Canada.

This report seeks to articulate those clear and repro-ducible determinants which identify successful treat-ment outcome measures for implants supporting func-tioning dental prostheses. In an attempt to reach thisobjective, each of the four groups was provided withprinted material to use as a starting point or scaffoldingfor focused debate. The material comprised the origi-nally proposed Albrektsson et al. (1986) and Smith andZarb (1989) Success Criteria, plus the Guckes et al.(1996) Classification of Treatment Outcomes inImplant Therapy. The participants were given instruc-tions to massage, edit, replace, etc., any or all of theoriginal criteria; to consider merits of a set of patient-mediated criteria from dentist-mediated ones (althoughit was clear that responsible professional behavior hadrecognized the twin concerns); and finally to addressthe question of the need to identify specific and rele-vant soft-tissue criteria.

Group A was co-chaired by Drs. Franks and Lloydand ably assisted by Dr. Anderson. They concluded thatall future implant research must include patient-basedoutcomes that reflect degrees of satisfaction with treat-ment, quality of life, oral health status, selected mor-bidities, and economic impact. They also proposed thatcriteria derived from patient-based outcome measuresshould be recorded in terms relative to expectationsand hopes, so as to permit an estimate of anticipatedbenefit and judgment of success. While it was self-evi-dent that the outcome criteria employed to date didnot preclude patient-mediated concerns, it was empha-sized that the latter required more rigorous compila-tion of quantifiable data to ensure informed clinicaldecisions.

Groups B, C and D were chaired by Drs. Laskin andLaney, Drs. McGivney and Fritz, and Drs. Becker andWeber, respectively. Their approach emphasized theother side of the coin of therapeutic outcomes, namelydentist-mediated concerns. This was achieved by build-

ing upon a critical assessment of criteria available todate. It was also recognized that individual implant suc-cess should not be assessed separately from an answerto the most compelling question of all: did the implantprescription yield a successful prosthodontic result?The following conditions for criteria application forsuccessful outcomes with implant-supported prosthesesare proposed:

(1) Implant therapy is prescribed to resolve prostho-dontic problems by permitting diverse prosthodontictreatments, which in turn impact upon the economicsof the service. Such prostheses should allow for routinemaintenance and should permit planned or unplannedrevisions of the existing design. Treatment outcomesuccess criteria for implant-supported prosthesesshould also be assessed in the context of time depen-dent considerations for any required retreatment.

(2) Criteria for implant success apply to individualendosseous implants, and

(a) At the time of testing, the implants havebeen under functional loading;

(b) All implants under investigation must beaccounted for;

(c) Since a gold standard for mobility assess-ment is currently unavailable, the method usedmust be specifically described in operative terms;

(d) Radiographs to measure bone loss shouldbe standard periapical films with specified refer-ence points and angulations.

The success criteria comprise the following determi-nants:

(1) The resultant implant support does not precludethe placement of a planned functional and estheticprosthesis that is satisfactory to both patient and den-tist.

(2) There is no pain, discomfort, altered sensation orinfection attributable to the implants.

(3) Individual unattached implants are immobilewhen tested clinically.

(4) The mean vertical bone loss is