One of the challenges I run into with implant dentistry is managing the crew access holes. Now we all hope to fill them once and then never have to get to the head of the screw again, but this is dentistry after all and that would be unrealistic. In the last 6 months I have partnered with two patients to replace implant supported hybrid prostheses, and had to remove and replace the old restoration at every appointment managing the access holes.
Last week I began sharing a treatment planning approach to implant placement and sequencing. It looked at clinical situations that would be best served by immediate placement or hard tissue preservation or augmentation. This second part will look at case scenarios that should be evaluated for soft tissue preservation/augmentation, a combination of soft and hard tissue procedures or can be dealt with effectively by allowing natural healing after extraction.
Soft Tissue Preservation/Augmentation:
- Sites planned for implants with thin or highly scalloped tissue
- Sites planned for implant placement with a deficit of tissue or discolored tissue
One of the challenges we face today is treatment planning and sequencing implant placement. One decision is whether to use immediate placement or delayed placement of the fixture. We also have to decide how to manage the implant site and extraction. Hard tissue augmentation or preservation may be indicated, along with soft tissue augmentation.Of course once we decide which procedures are recommended and the timing, we then have to make specific decisions on how those procedures will be accomplished. Dr. Ronald Jung presented a systematic way to look at these options and sort through them based on the clinical parameters of the case. These two posts will share that system with you.
Last week I attended the Seattle Study Club Annual Symposium. As is always the case when I attend continuing education, I think of all the patients in my practice this learning applies to. Sometimes I get lucky and I haven’t finished their treatment and still have a chance to implement this new learning. Last week was no exception, and several of the speakers spoke on the challenges of anterior esthetics using implants and how we can optimize the results through planning. Dr. Maurice Salama presented on “The Central Lateral Dilemma”, and the timing was perfect as I am just embarking on a complex restorative case with this exact scenario.
In yesterday’s post I looked at the thought process of using a screw retained versus a cement retained implant crown. If the choice is made to utilize a cement retained implant crown the next question is what kind of cement will you use. Many practitioners are devoted to the concept of only using provisional cements in these situations. Many others are very comfortable utilizing a permanent cement for implant crowns. So why do one or the other. the primary reason behind using a provisional cement is the ability to retrieve the crown and be able to access the abutment and screw. On the other side of the equation is using a permanent cement whose advantage is retention. Retention and retrievability are on opposite sides of the equation, and when you increase one you decrease the other.
Another piece of learning for me out of this week’s symposium was about the design of implant abutments in the esthetic zone. A common challenge with implant restorations is that the interface between the abutment and the crown is placed further apically then it should be. Our thinking behind this is to utilize the emergence profile of the crown to help develop and hold tissue form. The final pink esthetics are founded on the surgical outcome and developed and maintained by the abutment design. The tooth esthetics is controlled by the crown.
In the last two days I have heard some really wonderful presentations on implant dentistry. From treatment planning to cementation I have lots of new ideas to take back to my patients that I will share in the next few blog posts. One such idea was addressed cementation of the final crown over an implant abutment. One of the reasons we see changes in the soft tissue and bony topography after placing an implant restoration is cement remaining below the restoration margin. This cement situated between the abutment and the junctional epithelium acts as an irritant. The results can range from gingival irritation to osseous recontouring around the fixture.
My partner Scott had a patient in this afternoon to try to save an implant retained bar that supported a denture. The original bar did not fit passively and allow all the fixtures to be engaged. Two of the fixtures had lost bone around the top few threads and were suffering from peri-implantitis. There were several challenging pieces of the appointment, not the least of which was sectioning the bar after it was removed so it could be reassembled with Duralay pattern resin allowing the lab to solder it back together for a passive fit. I have had the pleasure of sectioning a bar before and I struggle with several things. First they are difficult to hold. Second it is tedious to cut through the metal, and you have to choose between it getting hot enough to burn your fingers, or spraying water all over the place out of the handpiece. Today I learned a great combination of clever ideas that eliminate the heat, mess and instability of this procedure.
Women Dentist Journal
Lee Ann Brady DMD
Not many years ago, dental implants were new, fascinating, and experimental procedures that could restore patients to a higher level of function. Times are changing. It is becoming increasingly common in my practice for patients to already be familiar with dental implants. They ask me to help them understand what role implants might play in replacing missing teeth or allowing them to transition away from removable prosthetics.
As implant technology and surgical techniques advance, our criteria for success needs to advance as well. The days are gone when successful integration of a fixture measured success. We need to add obtaining optimal esthetics and functional results to our criteria for satisfaction. Obtaining naturally beautiful esthetics, optimal function, and predict- able long-term results starts with a comprehensive evaluation. I begin by getting to know my patients so I can understand how dental implants will help accomplish their goals for dental health. Then I discover the technical components of their dental conditions.
Dental breakdowns result when two factors become out of balance with a patient’s adaptive capabilities, bugs, and forces. Dental implants and teeth respond differently in the presence of these two factors. For each patient, achieving success begins with understanding present risk factors and their susceptibility to both. Optimal survival rates for dental implants occur when the fixtures are placed in environments free of inflammation and infection. As part of a comprehensive evaluation, I complete a thorough periodontal examination, including full-mouth sulcus depths, furcation involvements, attachment loss, mobility, tissue character, and home-care evaluation. The team’s goal is to assist patients in getting their mouths healthy and clean in a maintainable way, prior to implant placement and final restorative therapy.
In addition to peri-implantitis, research shows that failure of implants following successful integration can be linked to overload. To minimize this risk, we must understand and manage each patient’s occlusion. (I gain an understanding of how a patient’s mandible arc is in centric relation and the relationship of the upper and lower teeth as they contact in this arc, centric occlusion.) The presence of a first point of contact and slide from centric occlusion to the maximal intercuspal position represents a risk factor for potential occlusal overload. Managing this will become part of the final treatment considerations.
As part of understanding the occlusal risk factors, I evaluate a patient’s functional occlusion, including the number and placement of contacts in MIP along with the existing anterior guidance. The presence of unbalanced occlusal contacts, muscle dis-coordination upon clenching, inadequate anterior guidance, and inadequate crossover guidance must be addressed to minimize the risk of occlusal overload. Parafunctional or dysfunctional activity pose increased risk of implant failure, so during the occlusal examination, I observe any signs or symptoms of occlusal disease such as wear, crazing, cracks, fractures, fremitus, and others. To complete the occlusal evaluation, I take impressions along with a facebow and bite registration to create a 3-D record of a patient’s existing occlusal relationships and functional patterns.
The stability of a patient’s occlusion depends in part on the stability of the temporomandibular joint, so I take a thorough history. The joints are palpated and a load test is completed to understand the relationship of the condyle disk assembly. The connection between the joints and the occlusion is mediated by the musculature, so a muscle exam with palpation and range-of-motion measurements is done. Positive response to muscle palpation means the system is overloaded and that time must be spent understanding the interrelationships more thoroughly prior to proceeding with definitive therapies.
Often, a patient and I need to gain insight into what he or she does with the teeth beyond normal function, or, as a means to verify centric relation, we progress into bite-splint therapy. A patient’s time with the bite splint is invaluable because it affords me the opportunity to evaluate the presence of occlusal habits and design an appropriate occlusion that will optimize forces along the long axis of teeth or implant fixtures and create anterior guidance. For some patients, the bite splint becomes part of our long-term plan to manage occlusal risk factors following restorative care.
Achieving an optimal esthetic result begins at the evaluation. I include a complete set of diagnostic digital photographs at every evaluation. I take several full-face and profile images to assess facial esthetics and their relationship to the appearance of the teeth. Close-up images allow the patient and me to discuss tooth display at rest and full smile, gingival discrepancies, gingival display, and smile appearance, in addition to shade and tooth position. When the restorative phase is complete, I want it to be difficult to discern natural teeth from the restorations. Of- ten, changes such as periodontal surgery or orthodontic repositioning must be made pre-restoratively.
Implant dentistry has evolved beyond placing the fixtures where there is existing bone without regard for the restorative and esthetic consequences. Now, understanding the anatomy of the soft and hard tissues as they affect implant placement is part of the preliminary information that must be gathered. Digital photographs, in addition to their use in esthetic evaluation and planning, are invaluable tools for evaluating soft-tissue contours. This information, along with the clinical soft-tissue exam and the models, give me a complete picture of the soft-tissue parameters that affect the implant-placement outcome. I also need a clear picture of the hard-tissue anatomy, so during the past few years, I added CT imaging to the diagnostic data I collect for cases in which I contemplate implants. These images allow implant surgeons and me to have thorough understandings of the bony architecture and anatomical factors, such as maxillary sinus and inferior alveolar nerve position in areas where we plan to place fixtures. We can then incorporate site-augmentation procedures if needed to achieve optimal results.
Implant dentistry is most often accomplished using a team of dentists who work together to accomplish the restorative and surgical treatment. Part of planning for success means giving each member of the team (orthodontist, periodontist, implant surgeon) an opportunity to become familiar with patients’ conditions. Once this has been accomplished, team members discuss each case and how we can help one another accomplish the best results. The removal of teeth prior to implant placement is one of the many topics our team works out to optimize results. This can be critical in implant-site preservation and creation. The timing of this treatment and who will be responsible for extractions must not be overlooked.
Another tool our team uses to create optimal implant placement sites is orthodontic extrusion of hopeless teeth prior to their removal. Some- times this is in conjunction with other orthodontic therapies to align adjacent teeth, create space for implant fixtures, or correct gingival discrepancies. Or, it can be the reason for planned orthodontics. For treatment to proceed seamlessly, these issues and many others must be well coordinated by a team. Often, we invite patients to these planning sessions, or we come together following our planning sessions with patients to answer questions and present treatment.
The first objective is periodontal health and stable dentition. In con- junction with this, we verify centric relation and move toward an occlusal scheme in which the patient’s joints are seated with muscles relaxed, and when they close, all teeth touch simultaneously. When force is applied, neither the jaw nor any tooth deflects. With teeth in contact, if the patient moves his or her lower jaw right, left, forward, or backward, no posterior tooth touches before, harder than, or after any anterior tooth.
The final piece of the diagnostic puzzle is the restorative work-up. The final prosthetic result is worked up on a set of mounted models, including soft- and hard-tissue augmentation, final tooth placement based on esthetic and functional parameters, and refinement of the occlusion. This work-up then can be used to create surgical guides for site-augmentation surgery that is planned as a separate procedure from final implant placement. A copy of the proposed prosthetic result is fabricated and impregnated or coated with a radiopaque material so that the patient may have a CT image taken with the prosthetic mock-up in place. This image is then used to finalize planning for the implant placement and any necessary site-augmentation procedures not yet accomplished. The image is exported into a software program. Fixture placement is planned so that the abutments are contained within the restorative framework without compromising embrasure spaces or forcing the restorative too far to the buccal or lingual, while being able to see the bony architecture and choose the optimal fixture sites at the same time. We choose the implant length and diameters based on existing anatomy or augment the site to use the fixture of our choice. The image also allows us to analyze the crown-to-fixture ratio of the final result based on existing ridge, or optimize the long-term outcome by grafting the site and reducing this ratio.
This final piece is crucial in planning the timing and sequencing of surgical treatment, as well as making sure that the fixture placement supports the optimal restorative outcome. Understand the patient’s present condition, manage any risk factors, and thoroughly plan. These allow us to achieve the patient’s desired functional and esthetic results with predictable long-term success.