Full-Arch Fixed Screw-Retained PFM Implant Restoration

Transcription

1 Volume 35 No. 6 Page 72 Full-Arch Fixed Screw-Retained PFM Implant Restoration A New Look at a Proven Technology Authored by Jack Piermatti, DMD Upon successful completion of this CE activity, 2 CE credit hours may be awarded. Opinions expressed by CE authors are their own and may not reflect those of Dentistry Today. Mention of specific product names does not infer endorsement by Dentistry Today. Information contained in CE articles and courses is not a substitute for sound clinical judgment and accepted standards of care. Participants are urged to contact their state dental boards for continuing education requirements.

2 Full-Arch Fixed Screw-Retained PFM Implant Restoration: A New Look at a Proven Technology Effective Date: 6/01/16 Expiration Date: 6/01/19 About the Author Dr. Piermatti, a Diplomate of the American Board of Prosthodontics and a Fellow of the American College of Prosthodontists, maintains a private practice limited to prosthodontics and implant dentistry in Voorhees, NJ. He is an associate professor of graduate prosthodontics and the director of the dental implant maxicourse at Rutgers University School of Dental Medicine in Newark, NJ. He can be reached at (856) , via at jpiermatti@yahoo.com, or via the website dentalartsofsouthjersey.com. Disclosure: Dr. Piermatti discloses that he has received honoraria for lecturing from Nobel Biocare. INTRODUCTION Diagnosis and treatment planning is widely considered the hallmark of successful prosthodontics. Incomplete or incorrect evaluation of questionable teeth can lead to early failure of dental restorations. When proper diagnostic criteria are employed using data from evidence-based literature, a level of confidence can be assigned to the treatment plan developed. When diagnosing a terminal dentition, the patient is generally given treatment choices, which involve either a fixed or a removable restoration. If the patient elects to have a fixed restoration, the edentulous arch will typically involve the use of endosseous root-form titanium implants. The purpose of this clinical article is to discuss the clinician s choices regarding technique as well as the materials used when providing a fixed restoration supported by titanium implants. Brief Historical Background In 1985, a group of authors published a book that helped to revolutionize dentistry. The publication, Tissue Integrated Prosthesis, described a method of solving the problem of edentulism through placement of titanium dental implant fixtures in the edentulous jaw and securing a prosthesis to those implants with fixation screws. This publication detailed a successful protocol backed by evidence-based research out of Sweden led by Professor P. I. Brånemark. The research showed 30 years of successful osseointegration of titanium dental implants in living bone. 1 The original protocol advocated treatment of the edentulous jaw with placement of multiple dental implants and insertion of permucosal abutments ultimately with screw-retention of the final prosthesis. The prosthesis was constructed with a metal substructure made with precision interfaces to the abutments and overlaid in acrylic with denture teeth completing the occlusion. Since the prosthesis was actually a denture that became a fixed restoration, the word hybrid came into the dental lexicon. The prosthesis was a cross between a denture and a fixed crown and bridge restoration, but the hallmark of this restoration was a fixed, retrievable dentition. Implant Dentistry Has Evolved Contemporary implant dentistry defines both simple and complex reconstructive cases and has evolved beyond the original treatment of edentulous arches with screw-retained, hybrid restorations for improved masticatory function. Single-unit implant restorations as well as short-span bridges are often planned as cement-retained prostheses since ideal aesthetics for anterior restorations and definitive occlusal surfaces for posterior restorations can be achieved. In these instances, clinicians may forego retrieveability and plan for cement retention. Generally speaking, it is preferred that large full-arch reconstructions be screw-retained, as complications in long-span prostheses are more common than in shortspan prostheses. 2 Complications can be encountered during fabrication of the prosthesis as well as those seen after delivery of the prosthesis. When screw retention is used, technical and eventual biological complications can be treated more easily. 3 Since implant dentistry has become so deeply ingrained into our treatment philosophy, dental implant patients have become an integral part of our practices. Recall maintenance of implant patients presents the same challenges as with all other dental patients. Poor oral hygiene, lack of compliance, oral pathology, trauma, and more are all issues that compromise dental health. Extensive implant restorations completed with cement retention oftentimes preclude prosthesis modification, material repair, surgical intervention for biological reasons, or any other indication requiring retrieveability. In contemporary prosthodontic, periodontic, and oral surgical practices, implant restorations are common, considering 2.3 million implant-supported crowns are made annually. 4 Managing complications of these restorations is unquestionably easier if screw retention is used. Multiple options exist with respect to technique and materials used in the fixed screw-retained implant restoration. 1

3 Milled monolithic zirconium, milled zirconium overlaid in feldspathic porcelain, milled titanium overlaid in acrylic resin, and milled chrome-cobalt overlaid in acrylic or porcelain have all been shown to be acceptable choices. 5 Combination techniques have also been popular, such as a milled titanium substructure with individual cemented crowns made in all the aesthetic materials available. While the author has had extensive experience with all the aforementioned techniques, he has not found any technique that demonstrates superior predictability, durability, aesthetics, problem-solving, and long-term functionality as the standard PFM restoration, a technology long used in prosthodontics. This restoration, when designed correctly with adequate metal support for veneering ceramics, satisfies all requirements for a prosthodontic rehabilitation. Definitive occlusal surfaces can be created in porcelain or alternatively may be made in metal if advisable. The metal framework can be tried clinically, sectioned, and laser welded, if required, to ensure a passive fit. If, after delivery of the completed restoration, modification is required for any reason, a section of the restoration can be cut out, a new section fabricated, and welded to the original, with porcelain repair to easily complete the modification. When the same restoration is fabricated with a substructure of titanium or zirconium, aesthetics are impressive; however, framework modifications are not possible. If prosthetic or biological complications arise after delivery, sections cannot be cut out. Instead, a new restoration must be made. These disadvantages must be considered when planning a full-arch fixed implant restoration. CASE REPORT Diagnosis and Treatment Planning A 55-year-old female in good health presented for diagnosis, consultation, and treatment. After thorough evaluation, the diagnosis was a maxillary terminal dentition with hopeless mandibular posterior teeth due to advanced perio dontal disease and caries (Figures 1 and 2). The mandibular anterior teeth exhibited attachment loss; however, they demonstrated minimal mobility and had excellent response to conservative periodontal management. It was decided to remove all maxillary teeth and mandibular molars, and replace missing teeth with implant-supported restorations. The remaining mandibular teeth would be treated conservatively with composite bonded restorations to eliminate diastemata. During the planning stages, the patient was unsure whether she wanted to retain the diastema between teeth Nos. 8 and 9, so the case was designed with 8 maxillary dental implants in order to be able to split the case into 2 separate restorations if the diastema was to be maintained. Figure 1. Preoperative clinical view. Figure 2. Preoperative radiographic survey. Figure 3. Panoramic radiograph showing placement of 12 dental implants. Clinical Protocol After completing conservative scaling and root planing of the mandibular teeth scheduled to be maintained, the patient arranged for her surgical visit. With the patient under intravenous sedation anesthesia, all remaining maxillary teeth were removed and an alveoloplasty was completed. Then, 8 NobelActive (Nobel Biocare) dental implants were installed in the positions of Nos. 3, 4, 6, 8, 9, 11, 13, and 14. Since implants were placed into fresh extraction sites, each alveolus was aggressively curetted of all residual granulation tissue. Anywhere a horizontal gap existed between the implant fixture and the alveolar wall, mineralized corticocancellous human bone allograft was placed, covered with resorbable collagen membrane, and primary closure was 2

4 achieved. The same procedure was repeated for the mandibular molars, placing implants into sites 19, 20, 29, and 30 (Figure 3). A complete maxillary denture was delivered, relined with a soft material, and all implants were allowed to heal for 3 months. After complete healing, implants were uncovered and healing collars were placed (Figure 4). The restorative phase of treatment began with fixture-level impressions of all implants using direct impression transfer copings luted together with self-curing resin (Figures 5 and 6). Impressions were made in irreversible polyether material (Impregum [3M]) and poured in lowexpansion dental stone (Resin Rock [Whip Mix]). A face-bow was used to orient the maxillary master cast, and the mandibular master cast was articulated using occlusion rims and interocclusal records, which allowed for setting the condylar inclination and Bennett angle of the semi-adjustable articulator (Hanau Wide-Vu [Whip Mix]) (Figure 7). Nonengaging temporary cylinders were inserted into the implant analogues of the master cast, and a full-contour wax-up of the case was done. Since the maxillary immediate denture was made using denture teeth that closely copied the size and shape of the patient s original teeth, a cast of the denture was used in the wax-up of the fixed case in order to again copy tooth size and shape. The wax-up was done with no regard for location of the access areas for screw-fixation (Figure 8). After completion of the wax-up, it was determined that the access locations exited the labial surfaces of Nos. 6, 8, 9, and 11. The wax-up was tried in the mouth to evaluate tooth position, aesthetics, phonetics, and occlusal relationship. After a satisfactory clinical evaluation, 17 screw-receiving, multiunit abutments were inserted into the implant analogues, nonengaging temporary abutments interfacing to these abutments were inserted, and the wax-up was modified in the areas of Nos. 6, 8, 9, and 11 to redirect the screw access openings to a favorable location (Figures 9). The full-contour wax-up was then indexed and converted into acrylic resin for a clinical trial period. This trial period is critical to evaluate tooth position, occlusion, phonetics, comfort, and aesthetics. Particularly important in this case was the aesthetic consideration as to whether a Figure 4. Implants with healing collars attached and ready for restorative phase. Figure 6. Mandibular direct impression transfer copings in place and luted with self-curing resin. Figure 8. Full-contour wax-up of maxillary arch. Note unfavorable access opening locations. Figure 5. Maxillary direct impression transfer copings in place and luted with self-curing resin. Figure 7. Master casts articulated on semi-adjustable articulator. Figure 9. Case re-waxed on anterior, angled, screw-receiving abutments. Note the favorable access opening locations. diastema would be incorporated into the final restoration (Figure 10). The acrylic resin restoration was delivered, and after a 2-week trial period, the patient reported excellent comfort, function, and phonetics. She did express a desire to restore her diastema in the final restoration. Since the restoration was successful except for the minor aesthetic change, impressions of the acrylic provisionals were taken and cross-mounted with the master casts. Full-contour wax-up of the anticipated definitive restorations was done utilizing palladium-based, 3

5 nonengaging waxing sleeves direct-to-fixture in the posterior area, and direct-to-multiunit abutments in the anterior areas, incorporating a diastema between Nos. 8 and 9. The waxed sections were cast in a silver-palladium ceramic alloy (Evolution Lite [Ivoclar Vivadent]) and prepared for clinical try-in (Figure 11). After verification of passive fit, the mandibular anterior natural teeth were adjusted and restored with composite resin (TPH Spectra [DENTSPLY International]) to eliminate interproximal spacing and minor carious lesions. Feldspathic porcelain (Creation CC [Klema Dentalprodukte; Austria]) was applied to the metal castings and adjusted during a final clinical try-in. A clinical re-articulation of the case was done for final occlusal adjustments and glazing. The case was delivered for a 2-week trial period. After complete patient satisfaction, all screws were tightened to the manufacturer s recommendations and access openings were filled with a Teflon base and composite resin (Figures 12 and 13). The patient has been followed with routine maintenance and experienced no adverse sequellae. Figure 10. Full-arch acrylic provisional restoration. Note that anterior units interface to angled abutments; posterior units interface direct to implants. Figure 12. Maxillary full-arch case delivered. Figure 11. Maxillary full-arch metal framework with opaque layer on master cast. Figure 13. Mandibular posterior units delivered. Anterior teeth restored with composite resin. CLOSING COMENTS A transition of the terminal dentition in the maxillary arch to a complete, implant-supported restoration can be a demanding undertaking. The result must be a definitive restoration that satisfies patient comfort, function, phonetics, and aesthetics. Additionally, it must be self-cleansable for acceptable oral hygiene, and exhibit predictable durability since restorative complications are frustrating to patient and doctor alike. During the diagnosis and treatment planning phase of implant dentistry, it is important to consider the choices clinicians have in dental materials. When the full-arch implant case is planned, there are several acceptable techniques to restore patients to optimal health and function. The full-arch fixed screw-retained PFM implant restoration is one acceptable technique.f References 1. Brånemark PI, Zarb G, Albrektsson T. Tissue Integrated Prosthesis. Chicago, IL: Quintessence Publishing; Wittneben JG, Millen C, Brägger U. Clinical performance of screw- versus cement-retained fixed implant-supported reconstructions a systematic review. Int J Oral Maxillofac Implants. 2014;29(suppl): Sailer I, Mühlemann S, Zwahlen M, et al. Cemented and screw-retained implant reconstructions: a systematic review of the survival and complication rates. Clin Oral Implants Res. 2012;23(suppl 6): American College of Prosthodontists. Why see a prosthodontist? Gotoapro.org. Accessed February 17, Carames J, Tovar Suinaga L, Yu YC, et al. Clinical advantages and limitations of monolithic zirconia restorations for full arch implant supported reconstruction: case series. Int J Dent. 2015;2015:

6 POST EXAMINATION INFORMATION To receive continuing education credit for participation in this educational activity you must complete the program post examination and receive a score of 70% or better. Traditional Completion Option: You may fax or mail your answers with payment to Dentistry Today (see Traditional Completion Information on following page). All information requested must be provided in order to process the program for credit. Be sure to complete your Payment, Personal Certification Information, Answers, and Evaluation forms. Your exam will be graded within 72 hours of receipt. Upon successful completion of the post-exam (70% or higher), a letter of completion will be mailed to the address provided. Online Completion Option: Use this page to review the questions and mark your answers. Return to dentalcetoday.com and sign in. If you have not previously purchased the program, select it from the Online Courses listing and complete the online purchase process. Once purchased, the program will be added to your User History page where a Take Exam link will be provided directly across from the program title. Select the Take Exam link, complete all the program questions and Submit your answers. An immediate grade report will be provided. Upon receiving a passing grade, complete the online evaluation form. Upon submitting the form, your Letter of Completion will be provided immediately for printing. General Program Information: Online users may log in to dentalcetoday.com any time in the future to access previously purchased programs and view or print letters of completion and results. POST EXAMINATION QUESTIONS 1. When proper diagnostic criteria are employed using data from evidence-based literature, a level of confidence can be assigned to the treatment plan developed. 2. Evidence-based research out of Sweden, led by Professor P. I. Brånemark, showed 30 years of successful osseointegration of titanium dental implants in living bone. 3. Generally speaking, it is preferred that large full-arch reconstructions be screw-retained, as complications in long-span prostheses are more common than in short-span prostheses. 4. Managing complications of implant restorations is not any easier when screw-retention is used. 5. In the case presented, anywhere a horizontal gap existed between the implant fixture and the alveolar wall, mineralized, cortico-cancellous human bone allograft was not required. 6. In the case presented, the wax-up was done with high regard for location of the access areas for screw-fixation. 7. In the case presented, full-contour wax-up of the anticipated definitive restorations was done utilizing palladium-based, nonengaging waxing sleeves direct-to-fixture in the posterior area. 8. During the diagnosis and treatment planning phase of implant dentistry, it is important to consider the choices clinicians have in dental materials. 5

7 PROGRAM COMPLETION INFORMATION If you wish to purchase and complete this activity traditionally (mail or fax) rather than online, you must provide the information requested below. Please be sure to select your answers carefully and complete the evaluation information. To receive credit you must answer at least 6 of the 8 questions correctly. Complete online at: dentalcetoday.com TRADITIONAL COMPLETION INFORMATION: Mail or fax this completed form with payment to: Dentistry Today Department of Continuing Education 100 Passaic Avenue Fairfield, NJ Fax: PAYMENT & CREDIT INFORMATION: Examination Fee: $40.00 Credit Hours: 2 Note: There is a $10 surcharge to process a check drawn on any bank other than a US bank. Should you have additional questions, please contact us at (973) o I have enclosed a check or money order. PERSONAL CERTIFICATION INFORMATION: Last Name (PLEASE PRINT CLEARLY OR TYPE) First Name Profession / Credentials License Number Street Address Suite or Apartment Number City State Zip Code Daytime Telephone Number With Area Code Fax Number With Area Code Address ANSWER FORM: VOLUME 35 NO. 6 PAGE 72 Please check the correct box for each question below. 1. o a. True. o b. False 5. o a. True. o b. False o I am using a credit card. My credit card information is provided below. o American Express o Visa o MC o Discover Please provide the following (please print clearly): 2. o a. True. o b. False 3. o a. True. o b. False 4. o a. True. o b. False 6. o a. True. o b. False 7. o a. True. o b. False 8. o a. True. o b. False Exact Name on Credit Card Credit Card # Signature Expiration Date This CE activity was not developed in accordance with AGD PACE or ADA CERP standards. CEUs for this activity will not be accepted by the AGD for MAGD/FAGD credit. PROGRAM EVAUATION FORM Please complete the following activity evaluation questions. Rating Scale: Excellent = 5 and Poor = 0 Course objectives were achieved. Content was useful and benefited your clinical practice. Review questions were clear and relevant to the editorial. Illustrations and photographs were clear and relevant. Written presentation was informative and concise. How much time did you spend reading the activity and completing the test? What aspect of this course was most helpful and why? What topics interest you for future Dentistry Today CE courses? 6