2 Proceedings of the Third ITI Consensus Conference: Implants in Post-Extraction Sites
The International Team for Implantology (ITI) is an independent academic network that unites professionals from all fields of implant dentistry and related tissue regeneration. It is active in the fields of research, development, and continuing education, and is dedicated to the promotion and spread of knowledge about all aspects of implant dentistry and related tissue regeneration for the benefit of patients. To date, the ITI unites about 5000 Fellows and Members in more than 40 countries.
The ITI regularly draws up and publishes treatment guidelines that are based on comprehensive clinical studies and supported by long-term clinical results. The results of this commitment include, for instance, publications such as the ITI Treatment Guide and the ITI Consensus Papers.
The ITI organizes consensus conferences at five-year intervals to discuss relevant topics in implant dentistry. The first and second ITI Consensus Conferences in 1993 and 1997 (Proceedings of the ITI Consensus Conference 2000) primarily discussed basic surgical and prosthetic issues in implant dentistry.
The third ITI Consensus Conference was convened in 2003. For this conference, the ITI Education Committee decided to focus the discussion on four special topics that had received much attention in recent years, “Implants in Extraction Sockets” (current terminology: post-extraction sites) being one of them (Proceedings of the Third ITI Consensus Conference, International Journal of Oral and Maxillofacial Implants, 2004. Vol 19, Supplement).
The objectives of the ITI Consensus Conference were to review the current literature in peer-reviewed journals and to discuss where sufficient evidence was available for specific clinical procedures and where evidence was lacking.
A working group was elected for the exploration of each topic. Working Group 1,under the leadership of Professor Christoph H. F. Hämmerle, was asked to review relevant literature, focus on, and find consensus relating to implants in post-extraction sites.
The participants of Working Group 1 were:
Jay R. Beagle
Stephen T. Chen
Louis Antonio Lima
Thomas von Arx
Thomas G. Wilson Jr.
2.1 Consensus Statements and Recommended Clinical Procedures Regarding the Placement of Implants in Post-Extraction Sites
The group was asked to develop evidence-based reviews on topics related to various placement protocols for dental implants. The following material was presented to the group for review and discussion:
Stephen T. Chen, Thomas G. Wilson Jr., and Christoph H. F. Hämmerle: “Immediate or Early Placement of Implants Following Tooth Extraction: Review of Biologic Basis, Clinical Procedures, and Outcomes” (Chen and coworkers, 2004)
The aim of this article was to review the current literature with regard to survival and success rates, along with the clinical procedures and outcomes associated with immediate and delayed implant placement.
The consensus statements and proposed clinical approaches defined by Working Group 1 on the topic of “Implants in Extraction Sockets”, as listed in Chapters 2.1.1 and 2.1.2 are intended to serve as a guide to clinicians in the diagnosis, treatment planning, and management of patients requiring dental implant therapy.
With the consensus statements as guidelines, it is hoped that clinicians will be better prepared to make informed surgical and prosthodontic treatment decisions to further enhance the quality of care and predictability of treatment outcome for their patients.
Results of clinical, radiologic, and histologic studies indicate that bony healing of extraction sites proceeds with external resorption of the original socket walls and a varying degree of bone fill within the socket.
Studies in humans and animals have demonstrated that at implant sites with a horizontal defect dimension (HDD; i.e. the peri-implant space) of 2 mm or less, spontaneous bone healing and osseointegration of implants with a rough titanium surface takes place.
In sites with HDDs larger than 2 mm and or non-intact socket walls, techniques utilizing barrier membranes and/or membrane-supporting materials have been shown to be effective in regenerating bone and allowing osseointegration.
Although scarce, the majority of the comparative data regarding the success of bone regeneration at peri-implant defects suggests no differences between Type 1, 2, and 3 procedures.
Further comparative analyses of different methods of bone augmentation with regard to successful bone formation and stability over time are required.
Long-term analysis of the stability of the regenerated bone is focused almost exclusively on radiographic assessments of the interproximal bone and implant survival. There is a need for studies to evaluate the fate of the buccal bone plate – whether regenerated or not – over time.
In most studies reviewed, broad-spectrum systemic antibiotics were used in conjunction with implant placement Type 1, 2, and 3. Controlled studies evaluating the effect of systemic antibiotics on treatment outcomes are needed.
Survival of Implants
The survival rate of immediately placed implants (Type 1) was reported in numerous studies to be similar to that of implants placed into healed ridges (Type 4).
In the few studies available, short-term survival rates of implants placed in conjunction with Type 2 and 3 procedures appear similar to those placed in Type 1 and 4 approaches.
There have been relatively few reports on the subject of Type 2 and 3 implant procedures, and only 2 of them were randomized with respect to timing of placement and augmentation methods used. Longitudinal studies of greater than 3 years’ duration were limited to 2 reports.
There is evidence to suggest that the survival rate for implants placed immediately following extraction of teeth associated with local pathology is similar to that of implants placed into healed ridges. Further controlled studies are required to provide definitive information about the management of these situations.
Esthetically pleasing treatment outcomes have received considerable attention in recent years; however, there are no controlled studies available on esthetic treatment outcomes in Type 1, 2, and 3 procedures.
All candidates for extraction-site implants should meet the same general screening criteria as regular implant patients, regardless of the timing of implant placement.
The literature is inconclusive regarding antibiotic use in conjunction with implant therapy. There is general agreement that the use of antibiotics is advantageous when augmentation procedures are performed.
Extraction techniques that result in minimal trauma to hard and soft tissue should be used. The sectioning of multi-rooted teeth is advised. All granulation tissue should be removed from the socket.
Site evaluation is critical to the determination of appropriate treatment modalities. Factors of concern include:
Overall patient treatment plan
Esthetic expectations of the patient
Soft tissue quality, quantity, and morphology
Bone quality, quantity, and morphology
Presence of pathology
Condition of adjacent teeth and supporting structures
Primary Implant Stability
The implant should not be placed at the time of tooth removal if the residual ridge morphology precludes attainment of primary stability of an appropriately sized implant in an ideal restorative position.
When treating patients with a thin, scalloped tissue biotype – even those with an intact buccal plate – concomitant augmentation therapies at the time of implant placement (Type 1) are recommended because of the high risk of buccal plate resorption and marginal tissue recession.
If buccal plate integrity is lost, implant placement is not recommended at the time of tooth removal. Rather, augmentation therapy is performed, and a Type 3 or 4 approach is utilized.
In cases involving a thicker, less scalloped tissue bio-type with an intact buccal plate, the need for concomitant augmentation therapies at the time of implant placement (Type 1) may be reduced, since thick bio-types have a decreased risk of buccal-plate resorption in comparison with thinner biotypes. As buccal-plate integrity is lost, the need for augmentation therapies increases.
When the buccal plate is compromised, negatively impacting the predictability of treatment outcomes, immediate (Type 1) implant placement is not indicated; rather, a Type 2, 3 or 4 procedure is carried out. When the HDD is greater than 2 mm, concomitant augmentation therapy needs to be performed.
Adjunctive augmentation therapies may be indicated in any of the above situations to optimize esthetic treatment outcome.
The three-dimensional positioning of the implant should be restoratively driven.
The Third ITI Consensus Conference took place in August 2003. The Consensus Statements phrased by Working Group 1 explored the topic of “Implants in Extraction Sockets” and were based on the body of literature available at that time.
Meanwhile, the topic of “Implants in Extraction Sockets” has been further researched, and additional literature has been published. In addition, new implant surface technologies and their influence on immediate and early placement protocols have been investigated.
Chapter 2.2, “Implants in Post-Extraction Sites – A Literature Update,” and Chapter 3.2, “Advantages and Disadvantages of Treatment Options for Implant Placement in Post-Extraction Sites” recognize the evolution of implant placement protocols, including recent data and literature, in order to give a state-of-the-art overview of implant placement protocols in connection with the clinical implications and applications to be derived from them.
S. Chen, D. Buser
Since the Third ITI Consensus Conference in August 2003, there has been a sustained interest in techniques for placing implants in post-extraction sites. Several randomized controlled clinical studies and a number of prospective and retrospective case series studies have been published to provide additional information regarding the clinical outcomes of this mode of treatment.
A number of descriptive terms have been used to indicate the timing of implant placement after the extraction of teeth. Wilson and Weber (1993) proposed the terms “immediate,” “recent,” “delayed,” and “mature” to describe the timing of implant placement in relation to soft-tissue healing and the predictability of guided bone-regenerative procedures using barrier membranes. In 1999, the terms “delayed” and “late” were used to describe time intervals of 6 to 10 weeks and 6 months or more after extraction, respectively (Mayfield, 1999). More recently, the term “early” implant placement has been used to describe implant placement after initial soft- and hard-tissue healing, but before complete healing of the socket has occurred (Chen and coworkers, 2004).
The variation in descriptive terminology in the dental literature was discussed at the Third ITI Consensus Conference, and a new classification system for the timing of implant placement after tooth extraction was proposed (Hämmerle and coworkers, 2004). This classification system is based on the desired clinical outcome of the wound-healing process, rather than on descriptive terms or rigid time frames following extraction. Thus, Type 1 placement refers to the placement of an implant on the day of tooth extraction and within the same surgical procedure. Type 2 refers to implant placement after soft-tissue healing, but before any clinically significant bone fill occurs within the socket. In contrast, Type 3 placement describes implant placement following significant clinical and/or radiographic bone fill of the socket. Type 4 placement refers to the insertion of an implant in a fully healed site. For the purpose of this review, t/>