High-end Implant and Ceramic Work Equals Natural Results

High-end Implant and Ceramic Work Equals Natural Results	August 2011
Artistic skill and ceramic work come together in this case.
The patient, a 75-year-old male, presented with non-restorable lower four anterior teeth. His partial was non-functional and his remaining maxillary teeth were few, leading him to wear a maxillary prosthetic appliance. After analyzing the X-ray and coordinating with the clinical findings, it was determined that the mandibular anterior teeth were non-restorable. Panorex X-ray also revealed that he did have, on a two-dimensional basis, adequate bone support from the apices of the non-restorable teeth to the inferior border of his mandible in the anterior component for implants. It was also noted he had moderate atrophy of the mandibular left and right posterior ridges. The CT scan1,2 of his mandible (Fig. 1) revealed that he had adequate bone thickness and bone density³ apical to the infected mandibular anterior teeth for four implants. Fig. 1: The CT scan verifies the bone density and thickness. Fig. 2: Stereo lithography and bone reduction guide. Fig. 3: The implants were surgically placed. Fig. 4: The temporary abutment verification index placed in the mouth ensures fit in the doctor's office. Fig. 5: A verification index was used to verify implant placement. Fig. 6: Light curing wax was applied over the lower UCLA abutments for design of the lower teeth. The treatment outline 4 was as follows: It was decided to use an interactive CT scan utilizing SimPlant (Materialise Dental) protocol to fabricate stereo lithography stents. One of these stents had a bone reduction guide for bone reduction in the mandibular anterior area (Fig. 2). The patient was prepped with standard operating procedures on an outpatient basis. We then proceeded to extract the mandibular non-restorable anterior teeth and at that time a bone reduction guide was placed over the osseous structures. It was determined that we would perform bone contouring in the mandibular anteriors to reduce the sharp ridges that remained after the extraction. The horizontal reduction of bone resulted in a wide buccal-lingual dimension so that circumferentially, implants would be completely encased in bone. Bone density using Hounsfield units was evaluated via SimPlant and showed that he had adequate bone density,5 which consisted of D1 and D2 bone for 15mmX5mm BioHorizon implants in the mandibular anterior area. After this, the bone reduction guide was used to reduce the bone height in the mandibular anterior and eliminate the sharp ridge. Four BioHorizon implants, 5mm in diameter and 15mm in length, were strategically placed in the mandibular anterior area (Fig. 3) and temporary abutments for verification index were placed (Fig. 4). After the implants were placed using the stereo lithography guides, the ridges in the posterior quadrants bilaterally (they had a knife ridge) were reduced in order to eliminate the disparity of ridge height. It was beneficial to level the bone throughout the mandibular arch by removing the very thin knife ridges in the posteriors. With the surgical reduction coping and the stereo lithography guide, the trimming of the bone of the posterior region resulted in an even osseous structure throughout the mandibular arch. The surgical protocol and implant placement resulted in excellent healing.6 Fig. 7: Primopattern LC paste was used to wax the framework. Fig. 8: The framework design was contoured. Fig. 9: The wax-up with UCLA abutments were spruced and ready for investing. Fig. 10: The framework was invested using GC Fujivest. Fig. 11: After casting, the restorations were placed on the model to ensure proper fit and design. Fig. 12: The porcelain's custom shade was checked on the model. Fig. 13: The author's multi-porcelain layering technique was utilized using GC Initial MC porcelain for life-like crowns. Fig. 14: After first firing, the porcelain had this appearance. Fig. 15: Porcelain build-up was checked for shade match. Fig. 16: Completed build-up appearance before firing Fig. 17: Side view, immediate placement Fig. 18: Gum color check, opposite side Approximately four or five months after the surgery, the mandibular anterior implants were exposed and healing caps were placed. The patient has good oral hygiene and was extremely compliant. After the implants were uncovered, standard operating protocol was instituted for impression taking using an open-tray technique. Verification jigs were fabricated and it was ascertained that he had a passive fit (Fig. 5). The protocol established was to place the patient in fixed restorations with four well-placed, well-integrated, long implants with UCLA abutments for design study, in good quality bone with the protocol of a fixed appliance (Fig. 6). The abutments were compared to the upper denture study model for proper design of the mandibular reconstruction. Maxillary reconstruction will also be planned after completion of the mandibular arch. After grinding the abutments for size check, light-curing wax was placed on top, burned out and cast, then baked at 1,550 degrees Fahrenheit (Figs. 7 & 8). Resulting frame design was completed and exhibited (Fig. 9) – ready for investing, with GC Fujivest the next completed step (Fig. 10). After casting, the restorations were placed on the model to ensure proper fit and design (Fig. 11) and the technician performed a custom shade check (Fig. 12). Using a porcelain multi-layering technique, GC Initial MC porcelain was applied by the technician for natural, life-like crowns (Fig. 13). The porcelain had this appearance after first firing (Fig. 14) and the build-up was then checked for shade match (Fig. 15). Before firing, the completed build-up had this appearance (Fig. 16). In a side view, after immediate placement, note the detailed design of the teeth (Fig. 17). The mesial of #27 was created to protrude slightly and the distal of #26 is purposely in slightly for a natural appearance. Likewise, the mesial of #26 is moved outward and the distal of #25 inward. For an exact match, (Fig. 18) the gum color was created using GC MC Gum Shade and the LSK Chairside Shade Guide system as a matching standard in order to reproduce excellent ceramic color for patient tissue. Close observation will reveal a medium pink base color, with a clear application on top and a slightly frosty layer to finalize the effect. Regarding the shape of the gums, the technician's goal was to create a healthy appearing gingival area by following a natural convex and concave flow to the tissue. Saliva underneath the gum tissue was mimicked for a life-like gum appearance, with a whitish horizontal line in the gingival third and translucency and opal, white and clear combination in the incisal third. In the incisal edge, an orange brown color was very lightly applied to mimic exposed dentin, but not severely. Interproximally, an appropriate amount of ochre stain further mimics the age of the patient's teeth. These modifications were applied based on the author's impression of the patient's existing dentition and his applied integration in order to create a vivid, life-like appearance. Understanding occlusion concepts, he knows that the mandibular needed to be built accordingly, taking into consideration the curve of Spee. Fig. 19: Front view (final) In the final full frontal view (Fig. 19), the concept of natural teeth is fully displayed. This restoration is an ideal example of a life-like case, with all the artistic skill and ceramic work coming together at the same time. These results were only possible due to perfect preparation and teamwork, all working in harmony. The proper tools – GC Initial pink porcelain for stump color and a shade guide that precisely mimics real color – contributed to the outcome, as well. These beautifully segmented teeth, flawlessly transitioned, offer a perfect solution to this patient's smile. The various prosthetic protocols were carried out for try-ins and establishing a proper plane of occlusion and the fixed bridge was screw retained. Excellent exit of the screw holes in the prosthesis was achieved, through planning, clinician-lab communication and also with stereo lithography stents that would allow the trajectory to be at the center of the cingulum of the implants. The case was extremely successful and the patient was pleased. Oral hygiene instructions were given to the patient. It is noted that on one of the photographs, he has a maxillary temporary denture only on several teeth. Phase II of this treatment will be to remove the remaining maxillary teeth and establish the same protocol of implant placement on the maxillary arch. The patient is in treatment for the maxillary arch and the part two would be to show the completed case with the maxillary reconstruction. References Sarment DP, Al-Shammari K, Kazor CE. (2003 Jun). Stereolithographic surgical templates for place ment of dental implants in complex cases. Int J Periodontics Restorative Dent. 23(3):287-95. Lal K, White GS, Morea DN, Wright RF (2006 Jan-Feb) Use of stereolithographic templates for sur gical and prosthodontic implant planning and placement. Part I. The concept. J Prosthodont. 15(1):51-8. Rebaudi A, Trisi P, Cella R, Cecchini G. (2010 Jan-Feb). Preoperative evaluation of bone quality and bone density using a novel CT/microCT-based hard-normal-soft classification system. Int J Oral Maxil lofac Implants. 25(1):75-85. Tischler M. 2010 Sep-Oct. Treatment planning implant dentistry: an overview for the general dentist. Gen Dent. 58(5):368-745. Turkyilmaz, I, Turkyilmaz, TF, Tumer, C. (2007 April). Bone density assessments of oral implant sites using computerized tomography. Journal of Oral Rehabilitation. 34(4):267-272. Abbo B, Razzoog. ME. 2007 Jul. Restoring the partially edentulous patient in the aesthetic zone: computer-guided implant surgery. Dent Today. 26(7):136, 138-40.
Author Bios
Joseph L. Caruso, DDS, MS, is licensed to practice dentistry in the states of Illinois and California and holds a specialty license in prosthodontics. His extensive training and experience include comprehensive and complex implant treatments along with full-mouth reconstruction emphasizing high aesthetic porcelain veneers and crowns. Dr. Caruso was awarded the Leonardo da Vinci Award for Excellence in Dentistry for 2005. He received his doctorate degree from Northwestern University's School of Dentistry and his master's degree in oral biology from Loyola University. He is active in continuing dental education and often lectures nationally and internationally on the latest diagnostic CT scans for implant and aesthetic techniques. He also participates in the testing and evaluation of advanced technological equipment and materials as they relate to modern clinical dentistry. He has been elected and is a fellow to both the American and International College of Dentists. Luke S. Kahng, CDT, is the owner of LSK121 Oral Prosthetics, a dental laboratory in Naperville, Illinois. In addition to being a board member for several dental publications, he has published more than 60 articles with major dental journals. He also lectures internationally, offering hands-on seminars to dental technicians and clinicians alike.The first edition of his highly successful Chairside Shade Selection Guide was launched in 2009, with international sales worldwide. Changes were incorporated into the second edition of the Chairside Shade Guide, launched in November 2010, with updating to include three components: posterior, anterior and rehabilitation design, specific for in-office custom shade matching techniques.He is the author of three hardcover books, including Anatomy from Nature, The Esthetic Guide Book and Smile Selection + CS³ Clinical Cases. Visit www.lsk121.com for more information.

Call Now San Francisco Dentist
Request for appointment at: (415) 391 - 7751
450 Sutter street, Suite 1905
San Francisco, CA, 94108
http://malidds.com/

Risk Factors and Treatment Fees for Implant Dentistry

Risk Factors and Treatment Fees for Implant Dentistry	August 2011
Get the facts from implant guru Dr. Carl E. Misch as he writes about implant dentistry today.
by Carl E. Misch, DDS, MDS, PhD (hc) Introduction Implant dentistry has become the most predictable method to replace missing teeth. However, treatment planning for implant dentistry is most often driven by the existing bone volume in the edentulous sites. This method is often problematic. In partially edentulous patients, more than 6mm of bone height is found in 40 percent of posterior maxillae and 50 percent of posterior mandibles. This percentage is further reduced to less than 20 percent of completely edentulous patients in either arch. The doctor and the patient often have an incentive to do treatment which is faster, easier and less expensive. The typical fees associated with treatment in implant dentistry are related to the number of implants and teeth replaced. Hence, a three-unit fixed partial denture supported by two implants is one-half the fee of a six-unit fixed partial denture supported by four implants. As a result, instead of bone grafts and posterior implants, distal cantilevers are often extended from anterior implants, since more vertical bone is found anterior to the maxillary sinus in the maxilla or the inferior alveolar nerve and mental foramen in the mandible. The primary cause of complications in implant dentistry is related to biomechanical factors, with too much stress applied to the implant support system. When implants are inserted into abundant bone volume and allowed to integrate for four or more months before loading, the surgical success rate is more than 98 percent. This success rate is not related to implant number, size or design. However, when the implant is occlusal loaded with the prosthesis, the failure rate might be greater than three to six times the surgical failure. For example, a meta-analysis reveals 15 percent failure rates (with several reports of more than 30 percent failure) when the implant prosthesis is occlusal loaded with implants shorter than 10mm, or when they are placed in softer bone. This failure most often occurs during the first 18 months of loading and is called early loading failure. Mechanical complications of the implant components or prosthesis outnumber surgical failures and many reports are more frequent than early loading failures. These complications include abutment screw loosening, uncemented prostheses and porcelain fracture. These complications are more often in bruxism patients, males, when opposing implant prostheses and with group function occlusion. All of the factors increase the amount of stress on the implant system (occlusal porcelain, cement, implant abutment screw and implant-bone interface). Biomechanical stress might also cause marginal crestal bone loss. Since the implant does not have a periodontal membrane as a tooth, the stress to the implant-bone interface is mostly to the crestal marginal bone. When the stress is beyond the bone physiologic limit, resorption might occur. The bone loss might increase the risk of anaerobic bacteria and peri-implantitis, or the surrounding soft tissues might shrink and result in poor cervical aesthetics. Hence, biomechanical factors can lead to early loading failure, mechanical complications and/or marginal bone loss around an implant. Stress Magnifiers Cantilevers on the prosthesis are one of the most significant stress magnifiers to the implant system. When used in the posterior regions, the greater bite force (up to five times greater than the anterior region), is further magnified and might increase the force on the implant system by three times. In order to eliminate posterior cantilevers, a bone augmentation is often indicated. Most bone augmentation procedures are not as predictable as implant integration in existing bone volumes. Bone augmentation often requires an additional surgery prior to implant placement. Additional training is required to learn bone augmentation procedures and the learning curve is longer and more difficult to become accomplished in these techniques. Complications related to bone augmentation are more common than implant surgery in existing bone volumes and might be more extensive and even debilitating to the patient. The discomfort following bone augmentation is usually more than occurs after implant surgery. An extended healing time of four to nine months might be necessary for the bone graft to mature, compared to implant healing in native bone. The costs associated with bone augmentation are often greater than the fees related to implant insertion. In addition, there are usually more implants and more teeth replaced after bone augmentation compared to situations when implants are inserted into existing volumes of the bone and teeth are cantilevered to the posterior regions. More implants and more teeth replacements further increase the cost to the patient. As a consequence of these considerations, the doctor and the patient are both motivated to use existing bone volumes for implants and restore fewer posterior teeth in the prosthesis, often with a cantilever. Risk Factors An example of the patient and doctor having incentive to perform procedures with higher risks is when a patient has four teeth missing in a posterior maxillary quadrant (two premolars and two molars), with a pneumatized maxillary sinus cavity. There are typically two treatment options. The first is to place two implants anterior to the sinus, which supports a three-unit prosthesis (with a first molar cantilever). A second option is to perform a sinus bone graft, the insertion of three implants (in the first premolar, first molar and second molar position) and to fabricate a four-unit restoration. Fees and Risk Factors The first treatment option is one-half the fee of the second option, since it doesn't require a sinus graft, has fewer implants and less teeth replaced. The first option is also faster and easier since a bone regeneration is not required. The patient undergoes one surgery and therefore experiences less discomfort. However, the second treatment option has three to four times better chance for long-term success, since it doesn't cantilever a pontic in the molar region. Since cantilevers increase the biomechanical force to the anterior implants, there is an increased risk of an unretained prosthesis on the first premolar (because of a tensile force to the retainer and cement is 20 times weaker to tension compared to compression). This results with one implant (the second premolar) supporting three teeth and the risk of overload and failure. The first treatment option more often has more bone loss from occlusal overload related to the increased biomechanical stress as a result of the cantilever (Fig. 1). In addition, the mandibular second molar might erupt past the plane of occlusion with the first option (since it only has one molar) and each protrusive mandibular movement would result in a lateral premature contact on the maxillary prosthesis. This bone direction increases the sheer force, and might even trigger parafunction. As a result, all complications related to stress are increased. Biomechanical-related complications often occur within the first few years of function. As a result, the patient expects the dentist to repeat the treatment for no charge. When the first option fails, the second treatment option might be selected, often from a different dentist, which is associated with a greater cost. As a result, the patient is more likely to bring litigation against the first treatment team in order to pay for the additional costs of the second treatment option. As a consequence of an increased risk of complications in the first treatment option, the fees for this option should be more than the second treatment option. In other words, the fee for services rendered should not only be based upon the sum of the number of implants and teeth in the prosthesis, it should also include the amount of risk associated with the treatment. A more basic example of charging for risk factors is the treatment for a crown on a maxillary central incisor compared to a mandibular molar. The time and technique for an anterior preparation, impression and transitional prosthesis is greater than to restore a mandibular posterior tooth. The risk that an anterior maxillary crown has to be redone because of gingival recession, shade selection, etc. is greater than the mandibular crown. Yet, most dentists charge the same fee for both procedures. The maxillary anterior crown has more risk, therefore the fee should be greater. Full-arch Restorations When a full-arch fixed implant restoration is the treatment for a maxillary arch, the number of implants is often the same as the mandible. For example, "all in four" is a common treatment option presented to the profession in either arch, along with similar fees for either arch to the patient. Yet, the maxillary fixed restoration is supported by softer bone. The hardness of the bone is related to its strength. The mandible more often has hard (strong) bone and the maxilla most often has softer bone. In fact, the posterior maxillary bone might be five to 10 times weaker than the hard bone of the anterior mandible. The maxillary anterior arch receives a force at a 12- to 15- degree angle during occlusion and up to a 30-degree angle in excursions. A 15-degree angled force increases the force component by 25.9 percent and a 30-degree force increases the force by 50 percent. The excursive forces in a maxillary restoration come from within the arch to push outside the arch. This force direction on an arch is more detrimental than in the mandible. The mandible receives a force from outside of the arch toward the inside of the arch, which is the direction of force the arch was designed to resist. The maxillary arch usually has shorter implants than the mandible (since the vertical height of bone is less compared to the anterior mandible). The shorter implants have less surface area and higher stresses, especially in soft bone. A literature review reports a failure rate three times higher in full-arch maxillary implant fixed restorations compared to full-arch implants and a mandibular restoration. Aesthetic retreatments and speech complications are more often observed in the maxillary restoration compared to the mandible prosthesis. The air can escape between the residual ridge and prosthesis, and aesthetic requirements for the patients are primarily obtained by the maxillary restoration. In other words, the maxillary full-arch restoration should be treatment planned differently and cost more than a similar restoration in the mandible. To compensate for the softer bone and higher biomechanical stress, the maxillary arch should more often have bone augmentation (to eliminate posterior cantilevers), more implants inserted and higher prosthetic fees than a mandibular arch. The fees for an implant treatment plan that has fewer implants and/or cantilevers should be greater than restorations supported by more implants and/or without cantilevers (Figs. 2-8). Summary The fees associated with implant surgery and prosthetic rehabilitation should be related to the risks related to the treatment. The treatment plan in implant dentistry should have a biomechanical rationale to decrease stress to the implant system. The risks in dentistry are a factor which should be included in the cost of most all procedures that are associated with greater complications. The implant and associated restoration is not a commodity in which the cost is solely related to the number of implants and prosthetic units. References 1. Goodacre CI, Bernal G, Rungcharassaeng K. Clinical complications with implants and implant prostheses. J Prosth Dent 90: 121- 132, 2003.
Author’s Bio
Carl E. Misch, DDS, MDS PhD (hc) is the professor and director of Oral Implantology at Temple Dental School in Philadelphia, Pennsylvania; and director at Misch International Implant Institute in Beverly Hills, Michigan.
Call Now San Francisco Dentist Request for appointment at: (415) 391 - 7751 450 Sutter street, Suite 1905 San Francisco, CA, 94108 http://malidds.com/