Restoration of the Edentulous Maxilla

Dr. Jameson is a board certified Prosthodontist who has done considerable work in disseminating information concerning the concept of linear non-interceptive occlusion. He was a consultant in Prosthodontics to the Surgeon General, USAF prior to his retirement from active duty and has been a consultant to the Department of Veterans Affairs. In this fourth interview, Dr. Jameson discusses some important and innovative approaches to restoration of the edentulous maxilla using implant prosthodontics.

Osseonews (ON): One of the areas that has received a great deal of attention recently is the use of free standing implant abutments in the edentulous maxilla to retain a maxillary overdenture. We briefly discussed this topic in your last interview
Dr. Jameson: As I have said, if the maxillary denture is adequate in fit, function and aesthetic quality, then two implants would be sufficient for retention with a tissue supported overdenture (i.e., RP5). Implants should never be considered as anything other than a supplemental tool in our restorative armamentarium and definitely not as a means of compensating for poorly designed or improperly fabricated prosthesis.
ON: In your opinion, do you feel that a tissue-supported overdenture (i.e., RP5) has a better prognosis in the edentulous maxilla than an implant supported overdenture (i.e., RP4)?
Dr. Jameson: In my hands, I would answer in the affirmative. Simplicity is always better than complexity. With the introduction of a bar to unite the implants, the possibility of error increases. The bar also complicates the placement of the anterior teeth as well as creating undesirable bulk to the lingual in the anterior. It also does nothing to prevent rotational movement, a precursor to Combination Syndrome (anterior hyperfunction) unless the use of additional posterior implants is feasible. The desires of the patient must be considered of course. If the need to expose the palate or have a fixed detachable prosthesis or fixed partial denture is so great that the added expense of additional implant fixtures and potential of compromised esthetics is secondary, then the decision must be made whether or not to accept the patient for treatment. For me, the disadvantages far exceed any perceived advantages and frankly, I would prefer not to treat the patient.
ON: You have mentioned previously that in the edentulous maxilla, implants placed in the canine eminence areas (i.e., #6 and 11) are sufficient for providing retention for an overdenture.
Dr. Jameson: In my opinion, yes. Implants should be used to provide that sense of added security patients sometimes desire. As I have indicated, non-interceptive linear occlusion is my occlusal scheme of choice with removable prostheses, implant retained or not. By eliminating lateral and anterior interferences, stability is enhanced and retention improved. If additional security is desired, then two implants will be sufficient.
ON: We have discussed ball-type attachments for use in the edentulous maxilla to support an overdenture. You indicated that you prefer the Sphero-Flex attachment (Preat Corp).
Dr. Jameson: I do simply because I find so many implant fixtures are not parallel. The Sphero-Flex compensates for divergent implants. Another excellent attachment for divergent implants is the Locator (Zest Anchors, Inc.). Size and the capability to alter the degree of retention are very positive advantages of the Locator.
ON: Do you prefer to pick up the Sphero-Flex attachment in the mouth or in the dental laboratory?
Dr. Jameson: Overall, the laboratory approach is safer and better unless of course subsequently placed implants makes retro-fitting of an existing denture necessary. If the retentive device is included in the trial base, the positioning and relief of the replacement prosthetic tooth eliminates the potential of some undesirable surprises at delivery. This approach also affords the opportunity to reposition the analog in the cast if necessary when the recording base is checked prior to the relationship record procedure. Using the retentive devices during the recording procedure reduces the chances of an inaccurate registration. The clinician can always do a direct pickup at delivery should an error occurs during processing. But it is much easier to block out undesirable undercuts in the laboratory than chair-side. So there are alternatives that can be employed if the impression is inaccurate, the analog was not stabilized during cast production or the retentive component moved during processing. But, if I can avoid an intra-oral pick-up, my life is much simpler and I am much happier.
ON: One thought I would like to leave with our subscribers is something that you have emphasized previously. Implant prosthodontics is ultimately prosthodontics. The same principles that guide restoration with conventional prosthodontics also guide restoration with implant prosthodontics. Implants aid in prosthetic rehabilitation.
Dr. Jameson: Absolutely. Every aspect of the restorative process, whether it is in conventional Prosthodontics or Implant Prosthodontics, must be accomplished with accuracy and meticulous attention to detail. Implants cannot be used to compensate for poor technique. In my opinion, using non-interceptive occlusion in the anterior as well as the posterior will in itself enhance stability and retention. Implants will then be icing on the cake so speak.