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CHAPTER 1: Introduction to the Updated SAC Classification
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 |
| Dean Morton | USA |
| Waldemar Polido | USA |
| Lira Rahman | Switzerland |
| Mario Roccuzzo | Italy |
| Irena Sailer | Switzerland |
| Charlotte Stilwell | UK |
| Mauro Tosta | Brazil |
| Alejandro Treviño Santos | Mexico |
| Daniel Wismeijer | Netherlands |
1.4 Potential Roles for the SAC Classification
On its surface, the SAC classification provides an assessment of the potential difficulty and risk of an implant-related treatment for a given clinical situation and serves as a guide for clinicians in both patient selection and treatment planning. In addition, it can also fulfill several additional roles.
Primarily, the classification scheme is aimed at providing clinicians with an objective and evidence-based framework against which they can assess clinical cases regarding the complexity of the planned treatment. This can then be used to assist them in deciding if they possess the necessary skills and knowledge to complete the treatment themselves, or whether referral to a more experienced clinician is indicated. With this capacity, they can build their experience in implant dentistry incrementally and minimize potential risk to their patients. Recently, the current SAC Assessment Tool validity was tested in regard to the agreement level between users, confirming its role as a clinical decision-making tool, as well as a valuable tool for the education of less experienced clinicians (Correia et al, 2020).
The SAC classification can also act as a checklist for more experienced clinicians to help them ensure that all relevant risks have been considered in the patient assessment and treatment planning phases of care.
Communication is a vital part of any step of patient management. In this regard, the SAC classification can aid in communication between clinicians as well as between them and their patients. The classification facilitates communication between colleagues by providing a known framework to exchange information: a shorthand that all involved clinicians are familiar with. When dealing with patients, clinicians can use the SAC classification of their situation to illustrate to patients the complexity and risks associated with their care. As such, it becomes an important tool not only in treatment planning but in the informed consent process as well.
Finally, the SAC classification can aid educators in developing training programs that gradually introduce increasingly more complex cases to their students, allowing an incremental development of knowledge and skill.
1.5 Using this Book
This book is intended to support your use of the SAC Assessment Tool that can be found at www.iti.org. Many sections of this publication are also supported by additional online information from the ITI Academy, the ITI’s e-learning platform, including learning modules and assessments, congress lectures, clinical cases, and Consensus Conference papers.
To view this additional material in full and for free, you need to be an ITI Member and logged in at www.iti.org.
Are you an ITI Member?
Please click here to log in to the ITI Academy or scan the QR code below:
Would you like to sign up for ITI membership?
Please click here or scan the QR code below:
Would you like to create a free ITI Academy account?
Please click here or scan the QR code below. Please note that only selected items featured in this publication will be available to view on the ITI Academy free of charge.
As soon as you have logged in or have created your free ITI Academy account, and if you are reading the print version of this publication, you can scan QR codes like the one below and will be taken to the corresponding item in the ITI Academy.
If you are an ITI Member and reading the online version of the book on the ITI Academy, you can also click on the link in the text that accompanies each QR code:
 | The SAC Assessment Tool distills the content of this book in an easy-to-use process that takes you through each step necessary to identify the degree of complexity and potential risk involved in individual clinical cases. To start your assessment, scan the QR code to the left or click on the link. |
CHAPTER 2: The Rationale Behind the Updated SAC Classification
A. DAWSON, C. STILWELL
Please refer to chapter 1, section 1.5 for information on the prerequisites for accessing the additional online information from the ITI Academy via the QR-codes and links provided in this chapter.
Please note that to view this additional material in full and for free, you need to be an ITI Member and logged in at www.iti.org.
2.1 Definitions
Case type A class of implant-supported prostheses that share similar defining characteristics. For example, implant-supported crowns for single-tooth replacements, or short-span implant-supported fixed dental prostheses replacing three or four teeth and supported by two implants.
Process: The implant dentistry “process” is defined as the full range of issues pertaining to assessment, planning, management of treatment, and subsequent maintenance of the implant and prosthetic reconstruction; it does not merely refer to the clinical treatment procedures that are involved.
Normative classification In this context, “normative” relates to the classification that conforms to the norm, or standard, for a given clinical situation in implant dentistry. The normative classification relates to the most likely classification of a case type. The final classification of a specific case may differ from the normative classification for the case type as a result of individual risk factors.
Timing of implant placement and loading: Loading and placement protocols have been investigated by the ITI at its last four Consensus Conferences. Hämmerle and coworkers (Hämmerle et al, 2004) defined the timing of implant placement relative to the event of tooth removal in a site, relating this to healing events rather than a specific time frame. This classification is detailed in Table 1.
Table 1 Implant placement protocols (Hämmerle et al, 2004).
| Classification | Definition |
| Type 1 | Implant placement immediately following tooth extraction and as part of the same surgical procedure |
| Type 2 | Complete soft tissue coverage of the socket (typically 4 to 8 weeks) |
| Type 3 | Substantial clinical and/or radiographic bone fill of the socket (typically 12 to 16 weeks) |
| Type 4 | Healed site (typically more than 16 weeks) |
 | Review article from the 3rd ITI Consensus Conference on the Placement of Implants in Extraction Sockets by Hämmerle and coworkers (2004). |
Implant loading protocols were also the subject of consensus conference reviews. At the Fourth ITI Consensus Conference, Weber and coworkers (Weber et al, 2009) defined the timing of implant loading relative to its placement. These descriptions are summarized in Table 2.
Table 2 Implant loading protocols (Weber et al, 2009).
| Classification | Definition |
| Conventional loading | Greater than 2 months subsequent to implant placement |
| Early loading | Between 1 week and 2 months subsequent to implant placement |
| Immediate loading | Earlier than 1 week subsequent to implant placement |
 | Review article from the 4th ITI Consensus Conference on Loading Protocols by Weber and coworkers (2009). |
Most recently, the relationships between the timing of implant placement (relative to the time that the tooth in the placement site was extracted) and the timing of loading of the implant with a provisional or definitive prosthesis in partially dentate patients were addressed by Gallucci et al (Gallucci et al, 2018). The outcomes of this review, correlating the evidence for the various combinations of placement and loading protocol, are summarized in Table 3. Protocols that had multiple high-quality studies were deemed scientifically and clinically validated (SCV) and could be seen as suitable for routine use by appropriately trained and experienced clinicians. Clinically documented (CD) approaches had less support in the published literature but did possess reasonable long-term clinical documentation to allow their use in specific situations. Finally, clinically insufficiently documented (CID) protocols lacked sufficient scientific evidence and clinical documentation to be recommended for use. This review built on previous consensus meetings where definitions of the placement and loading protocols were developed.
Table 3 Summary of placement and loading protocols (Gallucci et al, 2018).
| Loading protocol | |||
| Immediate restoration/loading (Type A) | Early loading (Type B) | Conventional loading (Type C) | |
| Implant placement protocol | |||
| Immediate placement (Type 1) | Type 1A CD | Type 1B CD | Type 1C SCV |
| Early placement (Type 2–3) | Type 2–3A CID | Type 2–3B CID | Type 2–3C SCV |
| Late placement (Type 4) | Type 4A CD | Type 4B SCV | Type 4C SCV |
 | Review article from the 6th ITI Consensus Conference on Implant Placement and Loading Protocols in Partially Edentulous Patients by Gallucci and coworkers (2018). |
Risk factors This term refers to any preexisting condition, treatment option, or material choice that may have an adverse effect on the outcome of treatment. These factors have the potential to influence the final SAC classification of a clinical situation.
