2 Proceedings of the Third ITI Consensus Conference: Loading Protocols in Implant Dentistry
With over 4500 Fellows and Members in more than 40 countries, the International Team for Implantology (ITI) is a non-profit academic organization of professionals in implant dentistry and tissue regeneration. The ITI organizes Consensus Conferences at 5-year intervals to discuss relevant topics in implant dentistry.
The first and second ITI Consensus Conferences in 1993 and 1998 (Proceedings of the ITI Consensus Conference, published in 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, “Loading Protocols for Endosseous Dental Implants” being one of them (Proceedings of the Third ITI Consensus Conference, JOMI Special Supplement, 2004).
One group, under the leadership of Professor David Cochran, was asked to focus on, review the relevant literature on, and find consensus relating to loading protocols for endosseous dental implants.
Robert A. Jaffin
2.1 Consensus Statements and Recommended Clinical Procedures Regarding Loading Protocols for Endosseous Dental Implants
The group was asked to develop evidence-based reviews on topics related to various loading protocols for dental implants. The following literature reviews were prepared and presented to the group for discussion:
Matteo Chiapasco: “Early and Immediate Restoration and Loading of Implants in Completely Edentulous Patients”
Jeffrey Ganeles, Daniel Wismeijer: “Early and Immediately Restored and Loaded Dental Implants for Single-Tooth and Partial-Arch Applications”
Dean Morton, Robert Jaffin, Hans-Peter Weber: “Immediate Restoration and Loading of Dental Implants: Clinical Considerations and Protocols”
The prime objective of the literature reviews was to determine whether a procedure could be recommended as routine based on the available evidence. The second objective was to identify whether patients perceived a benefit associated with these procedures.
At the ITI Consensus Conference, the authors presented their manuscripts to the group for discussion. There was discussion concerning how the authors approached writing the draft, how the literature was searched and reviewed, what the major findings were, and finally, what conclusions could be drawn.
During the discussion, several statements were made regarding immediate or early restoration and/or loading of implants in edentulous and partially dentate patients. These are listed below, along with issues that were identified throughout the discussions.
In recent years, confusion has been evident with terminology as it relates to loading protocols in implant dentistry. The group discussed this terminology in detail, in relation to both existing literature and ITI consensus. Most of these terms were defined in a conference on immediate and early loading that was held in Spain in May 2002 (Aparicio and coworkers, 2003). However, the group modified these definitions for use in their report. The modified definitions are presented here:
The prosthesis is attached in a second procedure after a healing period of 3 to 6 months.
A restoration in contact with the opposing dentition and placed at least 48 hours after implant placement but not later than 3 months afterward.
A restoration inserted within 48 hours of implant placement but not in occlusion with the opposing dentition.
A restoration placed in occlusion with the opposing dentition within 48 hours of implant placement.
The prosthesis is attached in a second procedure that takes place some time later than the conventional healing period of 3 to 6 months.
The choice of loading protocols should be viewed as dependent, among other factors on two distinct processes: primary and secondary bone contact. By understanding these concepts, it is possible to appreciate how various loading protocols are viable and why they are dependent on these processes.
Primary bone contact
As soon as an implant is placed into the jawbone, certain areas of the implant surface are in direct contact with bone.
Secondary bone contact
As healing occurs, the bone around the implant surface is remodeled, and areas of new bone contact with the implant surface appear. This remodeled bone and new bone contact, termed secondary bone contact, predominates at later healing times when the amount of primary contact is decreased.
Shortened loading protocols
Immediate and early loading protocols should focus on (1) the amount of primary bone contact, (2) the quantity and quality of bone at the implant site, and (3) the rapidity of bone formation around the implant.
When existing bone of high quality and quantity is found and when other factors are favorable, immediate loading of the implant may be possible.
If the existing bone is not of high quality and quantity, then bone formation must occur within a relatively short time so that early loading of the implants can take place.
Direct occlusal contact
In the case of direct occlusal contact, the restoration makes contact with the opposing dentition.
With indirect occlusion, the implant is restored without directly contacting the opposing dentition, i.e. it is out of occlusion.
With progressive loading, the implant is restored in “light” contact initially and is gradually brought into full contact with the opposing dentition.
With the understanding that the literature base is small and the strength of evidence graded as inadequate to fair, the group reached the following conclusions with regard to loading protocols for endosseous dental implants in 2003:
In edentulous mandibles, the immediate loading of 4 implants with an overdenture in the interforaminal area with rigid bar fixation and cross-arch stabilization is a predictable and well-documented procedure.
The early loading of implants (splinted or unsplinted) in the edentulous mandible with an overdenture is not well-documented.
Immediate loading of implants supporting fixed restorations in the edentulous mandible is a predictable and well-documented procedure, provided that a relatively large number of implants are placed.
The Consensus Group found only six publications supporting the early loading of implants in the edentulous mandible with a fixed restoration.
No articles were found supporting immediate or early loading of implants with an overdenture in the edentulous maxilla. Therefore, this procedure would have to be considered experimental at this time.
In the edentulous maxilla, immediate or early loading of implants utilizing a fixed prosthesis is not well-documented.
Partially Dentate Mandible or Maxilla
In the partially dentate maxilla and mandible, the immediate restoration or loading of implants supporting fixed prostheses is not well-documented. It should be noted that in many of these cases the restoration is not in contact with the opposing dentition. This observation highlights the care that must be expended to plan and successfully complete such a restoration.
The early restoration or loading of titanium implants with a roughened surface supporting fixed prostheses after 6 to 8 weeks of healing is well-documented and predictable in the partially dentate maxilla and mandible. Results seem to indicate that the outcome is similar to results obtained with conventional procedures. However, further studies are necessary before these procedures can be proposed as routine due to the limited number of implants placed in comparison to the number of conventionally loaded implants, and the short follow-up period.
Interproximal crestal bone levels and soft tissue changes adjacent to immediately restored or loaded implants were found to be similar to those reported for conventional loading protocols.
Other Issues Discussed
A conventional loading period of 3 to 6 months is likely to be modified for implants with roughened surfaces. The 3- to 6-month period was originally defined for implants with machined surfaces, and it is well-documented that the machined surface is not as successful as the roughened surface in certain indications.
A question that needs to be addressed is whether the patient benefits from an immediate or early loading protocol. There is an associated risk with immediate and/or early loading, and this risk must be evaluated in terms of patient benefit. Postoperative care must be evaluated in such calculations.
A related question is whether conventional loading is justified in certain cases. For example, does delaying the restoration of an implant place the patient at a disadvantage?
The types of occlusal schemes need to be specified in various loading protocols. Occlusal schemes for immediately and early loaded implants that result in successful outcomes need to be determined.
The following types of treatment were recommended by the Consensus Group in 2003 (published in a supplement of JOMI in 2004), provided that all other aspects of diagnosis and treatment planning have been performed and are considered acceptable by the clinician. Immediate restoration and loading procedures are considered advanced or complex. As such, it is assumed that the clinician has the requisite level of skills and experience. The recommendations are based on the literature available in 2003 and the collective experience of the Consensus Working Group.
Immediate Restoration or Loading:
Four implants are suitable for use in 2 protocols: an overdenture retained and/or supported by a bar that rigidly connects the implants, or a fixed restoration on a framework (acrylic resin and/or metal) that rigidly connects the implants. More than 4 implants are suited for rigid provisional restoration connecting all of the implants, or for a fixed restoration on a framework (acrylic resin and/or metal) that rigidly connects the implants.
No routine procedure is recommended.
Partially dentate maxilla and mandible
No routine procedure is recommended.
Early Restoration or Loading:
Two implants may be placed to retain an overdenture, supported by a bar connecting the implants or by freestanding implants, when the implants are characterized by a rough titanium surface and allowed to heal for at least 6 weeks.
In a four-implant scenario, either of two options is recommended: an overdenture retained and supported by a bar connecting the implants or by unconnected implants, or a fixed restoration on a framework that rigidly connects the implants. The implants should be characterized by a rough titanium surface and allowed to heal for at least 6 weeks.
More than four implants
More than four implants may be used for a fixed restoration on a framework that rigidly connects the implants; again, the implants are characterized by a rough titanium surface and allowed to heal for at least 6 weeks.
Four different early loading scenarios are possible:
Four implants retaining an overdenture…
…supported by a bar connecting the implants or by unconnected implants, with implants characterized by a rough titanium surface and allowed to heal for at least 6 weeks. The site must be characterized by type 1, 2 or 3 bone.
Four implants supporting a fixed restoration…
…on a framework that rigidly connects the implants. As with the above scheme, the implants are characterized by a rough titanium surface and allowed to heal for at least 6 weeks, and the site is characterized by type 1, 2 or 3 bone.
More than four implants retaining an overdenture…
…supported by a bar connecting the implants or by unconnected implants, with implants characterized by a rough titanium surface and allowed to heal for at least 6 weeks, in a site characterized by type 1, 2 or 3 bone.
More than four implants supporting a fixed restoration…
…on a framework that rigidly connects the implants. Again, the implants are characterized by a rough titanium surface and allowed to heal for at least 6 weeks, and the site is characterized by type 1, 2 or 3 bone.
Partially Dentate Maxilla and Mandible
A fixed prosthesis is recommended in these cases:
Implant number and distribution are dependent on patient circumstances…
…including bone quality and quantity, number of missing teeth, condition of opposing dentition, type of occlusion, and bruxism. Implants must be characterized by a rough titanium surface and are allowed to heal for at least 6 weeks and in type 1, 2 or 3 bone.