Chapter 1. Introduction to the SAC Classification
Chapter 2. Determinants of the SAC Classification
Chapter 3. Modifying Factors
Chapter 4. Classification of Surgical Cases
Chapter 5. Classification of Restorative Cases
Chapter 6. Practical Application of the SAC Classification
Chapter 7. Conclusion
2 The Determinants of the SAC Classification
A. Dawson, S.Chen
2.1 Definitions
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: 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 representation of the classification of a case. The normative classification may alter as a result of modifying factors and/or complications.
Timing of implant placement: A number of different classifications have been used to describe the timing of implant placement after tooth extraction. In this book, the classification detailed by Chen and Buser (2008), which is a modification of the classification proposed by Hämmerle et al. (2004), will be used. This classification is summarized in Table 1.
Table 1. Classification of the Timing of Implant Placement following Tooth Extraction (Chen and Buser 2008). Classification Descriptive Terminology Period after Tooth Extraction Desired Clinical Situation at Implant Placement Type 1 Immediate placement Immediately following extraction Post-extraction site with no healing of bone or soft tissues Type 2 Early placement with soft-tissue healing Typically 4 to 8 weeks Post-extraction site with healed soft tissue but without significant bone healing Type 3 Early placement with partial bone healing Typically 12 to 16 weeks Post-extraction site with healed soft tissues and with significant bone healing Type 4 Late placement Typically 6 months or longer Fully healed post-extraction site
Implant loading protocol: In discussions relating to the systems for loading implants after implant placement, the definitions used by Cochran et al. (2004) will be used. These are summarized in Table 2.
Table 2. Definitions of Loading Protocols (Cochran et al. 2004). Loading Protocol Definition Immediate restoration A restoration is inserted within 48 hours of implant placement, but not in occlusion with the opposing dentition Immediate loading A restoration is placed in occlusion with the opposing dentition within 48 hours of implant placement Conventional loading The prosthesis is attached after a healing period of 3 to 6 months Early loading A restoration in contact with the opposing dentition is placed at least 48 hours after implant placement but not later than 3 months afterwards Delayed Loading The prosthesis is attached in a procedure that takes place some time later than the conventional healing period of 3 to 6 months
2.2 Assumptions
This classification assumes that appropriate training, preparation and care are devoted to the planning and implementation of treatment plans. No classification can adequately address cases or outcomes that deviate significantly from the norm. In addition, it is assumed that clinicians will be practicing within the bounds of their clinical competence and abilities. Thus, within each classification, the following general and specific assumptions are implied:
General:
-
Treatment will be provided in an appropriately equipped operatory with an appropriate aseptic technique.
-
Adequate clinical and laboratory support is available.
-
Recommended protocols are followed.
Patients:
Specific:
-
The type, dimensions and number of implants to be placed are appropriate for the site.
-
The implants are correctly positioned and adequately spaced.
-
Restorative materials that are used are appropriate to the task.
2.3 Determinants of Classification
The normative classification for a given type of case will be determined based on the criteria outlined below.
General determinants of classification include:
2.3.1 Esthetic vs. Non-Esthetic Sites
The extent to which esthetic issues affect the process will be a general determinant. Cases in non-esthetic sites will have little or no esthetic risk, thus removing one potentially confounding factor. Straightforward cases must not, by definition, include any esthetic risk, and any case in the esthetic zone must be classified as either Advanced or Complex. In this context, an esthetic site is one in which the mucosal margins of teeth or tooth replacements will be visible upon full smile, or an area of esthetic importance to the patient (Belser et al. 2004).
2.3.2 Complexity of the Process
The level of complexity of an implant surgical or restorative treatment may be assessed by considering the number of steps involved in the procedure, and the number of areas in which an appropriate outcome must be achieved. As a general principle, the level of complexity rises with an increase in the number of steps involved and the number of objectives that must be achieved to attain a satisfactory result.
For example, a single-tooth replacement in a non-esthetic site may require limited planning. Surgery may involve an uncomplicated two-step process involving tooth extraction and subsequent implant placement some weeks later. The restorative phase of treatment may also involve an uncomplicated procedure. This case would, therefore, have a normative classification of Straightforward for both the surgical and restorative treatments. In contrast, a single-tooth restoration in an esthetic site will require more detailed assessment and planning, may involve more surgical and restorative steps, and must achieve somewhat more exacting outcomes. This process would have a normative classification of at least Advanced. While seemingly similar in application, these two examples demonstrate the increased complexity that attends cases in esthetically challenging sites.
Assessment of the complexity of a process can also be based on whether the outcome (and steps involved) can be predicted with some clarity. If they can, then classifications of Straightforward or Advanced may be appropriate (depending on other issues under consideration). In Complex cases the outcome is likely to be dependent on the success of intermediate procedures. This may require variations in the treatment plan and consideration of the associated contingencies. For example, if sinus grafting is necessary to place implants, the outcome of the procedure will, to a greater or lesser degree, affect the number, size and placement of implants, which in turn will affect the design of the final prosthesis. Thus, in the planning phase it is not possible to clearly envision the final outcome, leading to a classification of Complex.
2.3.3 Risks of Complications
No procedure is totally without risk of a mishap that may complicate the treatment or affect the long-term success and stability of the result. The SAC Classification can be used to identify and quantify these risks, thus allowing some contingency planning ...
