A. DAWSON, W. MARTIN, W. D. POLIDO
1.1 Introduction
Implant dentistry is an integral part of modern dental practice, providing a strong evidence-based option for the rehabilitation of partially and completely edentulous patients. Clinical and technologic advancements in this field have increased the level of confidence that clinicians have in this form of therapy and have also led to a broader base of incorporation into daily practice. What was once the domain of specialist practice is now a common treatment modality in many, if not most, general practices. This has increased the need for all clinicians involved with the field of implant dentistry, irrespective of specialty, to be able to provide therapy at an appropriate level of care.
It has long been recognized that clinical situations present with different levels of difficulty and with different degrees of risk for esthetic, restorative, and surgical complications. Despite the advances in knowledge and improved techniques, implant dentistry is not free from risks of complications or suboptimal outcomes. Over the last decade, research in this field has increasingly provided information regarding the risks associated with this treatment option. The successful osseointegration of an implant is no longer the primary focus of treatment. Rather, the range of potential problems with implants and their related prostheses has come into sharper focus. It is in this environment that the SAC classification has evolved to assist practitioners in recognizing risk factors and providing appropriate levels of care.
1.2 Historical Background
The concept of assessing risk factors in implant dentistry has attracted considerable attention since the early 1990s, when the number of clinicians placing and restoring implants increased significantly. With this increase in use, the number of associated complications also increased.
Renouard and Rangert (1999) published a classification system that addressed the risk factors involved with the surgical and restorative phases of implant rehabilitation. At that time, they affirmed that some risk factors are relative, while others are absolute. The distinction between the two is not as clear as it might appear. However, several relative contraindications or one absolute contraindication should lead to a reevaluation of the original treatment plan. Although they were using terms like “OK,” “Caution,” and “Danger,” and using the green, yellow, and red colors associated with increased risk factors, an integrated decision tree was not present.
The term SAC, with the associated risk factor classification and color scheme, was first used by its two creators, Sailer and Pajarola (1999), in an atlas of oral surgery, with the intent to classify risk factors for general dentists practicing dentoalveolar surgery. The authors described in detail various clinical situations for procedures in oral surgery, such as the removal of third molars, and proposed the classification S = Simple, A = Advanced, and C = Complex. This concept was then adopted in 1999 by the Swiss Society of Oral Implantology (SSOI) during a 1-week congress on quality guidelines in dentistry. The working group of the SSOI developed this SAC classification from a surgical and prosthetic point of view for various clinical situations in implant dentistry. This SAC classification was then adopted by the International Team for Implantology (ITI) in 2003 during the ITI Consensus Conference in Gstaad, Switzerland. The surgical SAC classification was presented in the proceedings of this conference (Buser et al, 2004). The ITI Education Core Group decided in 2006 to slightly modify the original classification by changing the term Simple to Straightforward.
Fig 1. The participants of the SAC Consensus Conference held by the ITI in Palma de Mallorca in March 2007. (Source: The SAC Classification in Implant Dentistry, 2009).
In March 2007, the ITI held a consensus conference in Palma de Mallorca in Mallorca, Spain aimed at improving on the SAC classification (Figure 1). In its initial form, the SAC classification tended to be subjective, as it related the perceived difficulty of the treatment to the individual practitioner. The Mallorca meeting sought to develop a classification scheme that was more structured and objective. The results of this conference were published in an adjunct to the ITI Treatment Guide series in 2009 (Dawson & Chen, 2009). Later in 2009, the ITI developed an SAC Assessment Tool that clinicians could use to determine the normative classification for a case type that they were treating and identify any additional modifying factors that might apply to their own patient’s clinical situation.
The participants in the first SAC Conference were as follows: Urs Belser (Switzerland), Daniel Botticelli (Italy), Daniel Buser (Switzerland), Stephen Chen (Australia), Luca Cordaro (Italy), Anthony Dawson (Australia), Anthony Dickinson (Australia), Javier G. Fabrega (Spain), Andreas Feloutzis (Greece), Kerstin Fischer (Sweden), Christoph Hämmerle (Switzerland), Timothy Head (Canada), Frank Higginbottom (USA), Haldun Iplikcioglu (Turkey), Alessandro Januario (Brazil), Simon Jensen (Denmark), Hideaki Katsuyama (Japan), Christian Krenkel (Austria), Richard Leesungbok (South Korea), Will Martin (USA), Lisa Heitz-Mayfield (Australia), Dean Morton (USA), Helena Rebelo (Portugal), Paul Rousseau (France), Bruno Schmid (Switzerland), Hendrik Terheyden (Germany), Adrian Watkinson (UK), and Daniel Wismeijer (Netherlands).
The 2009 version of the SAC classification scheme has received widespread acceptance in the dental profession and in the realm of dental education (Mattheos et al, 2014), where it has formed the basis of implant dentistry teaching in many predoctoral and postgraduate dental programs.
From its initial release in 2009, clinical techniques, materials, and technology have continued to evolve and, in early 2017, the ITI recognized that there was a need to review the SAC classification to ensure that it was still consistent with contemporary implant practice. A review group met in Zurich in October 2018, and again in Berlin in April 2019, to develop an updated SAC classification scheme. The primary aim of this review was to develop an updated SAC Assessment Tool, as this had been found to be clinicians’ favored way of determining the classification of their patients’ treatment needs. The publication of this book satisfies the secondary goal of the review: to document the rationale for this SAC Assessment Tool and the evolution of the SAC classification.
1.3 The Review Team
This text documents the proceedings of consensus meetings held by the ITI in 2018 and 2019. The following individuals contributed to the findings of this conference and the content of this publication (Figure 2):
Fig 2. Review team members.
| Paolo Casentini | Italy |
| David Cochran | USA |
| Anthony Dawson | Australia |
| Luiz Gonzaga | USA |
| Stefan Keller | Switzerland |
| Thomas Kiss | Switzerland |
| Johannes Kleinheinz | Germany |
| Ali Kökat | Turkey |
| William Martin | USA |
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