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Corresponding author: Dr Manrique Fonseca, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Freiburgstrasse 7, Bern 3010, SWITZERLAND
Associate Professor, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, SwitzerlandAssociate Professor, Department of Restorative, Preventive and Pediatric Dentistry, School of Dental Medicine, University of Bern, Bern, SwitzerlandAdjunct Professor, Division of Restorative and Prosthetic Dentistry, The Ohio State University, Columbus, Ohio
Professor and Chair, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, SwitzerlandSenior Lecturer, Division of Gerodontology and Removable Prosthodontics, University Clinics of Dental Medicine, University of Geneva, Geneva, Switzerland
This clinical report describes the treatment of a complex intraoral situation by fabricating a maxillary implant-retained overdenture with a high-performance polymer (polyetherketoneketone) framework and lithium disilicate crowns and mandibular tooth- and implant-supported ceramic restorations. No complications were noted in 2 years, and the patient was satisfied with function and esthetics.
In complex situations, proper treatment planning and prosthetic material choice is essential to ensure the predictability and longevity of implant-supported restorations.
The influence of prosthetic material on implant and prosthetic survival of implant-supported fixed complete dentures: a systematic review and meta-analysis.
Computer-aided design and computer-aided manufacturing (CAD-CAM) technologies have enabled the use of monolithic zirconia, carbon fiber, and high-performance polymers
Comparative in vitro study of the bond strength of composite to carbon fiber versus ceramic to cobalt-chromium alloys frameworks for fixed dental prostheses.
Short-term report of an ongoing prospective cohort study evaluating the outcome of full-arch implant-supported fixed hybrid polyetheretherketone-acrylic resin prostheses and the all-on-four concept.
Treatment of a mandibular discontinuity defect by using a fibula free flap and an implant-supported fixed complete denture fabricated with a PEKK framework: a clinical report.
A speech bulb prosthesis for a soft palate defect with a polyetherketoneketone (PEKK) framework fabricated by multiple digital techniques: a clinical report.
Short-term report of an ongoing prospective cohort study evaluating the outcome of full-arch implant-supported fixed hybrid polyetheretherketone-acrylic resin prostheses and the all-on-four concept.
However, the authors are unaware of reports describing the combination of a PEKK framework and lithium disilicate crowns for implant-retained overdentures. Clinicians may benefit from information on how PEKK can be used as an overdenture framework combined with lithium disilicate crowns in a complex situation.
This clinical report describes the rehabilitation of a patient by using a maxillary implant-retained overdenture with lithium disilicate crowns on a PEKK framework. The mandible was restored with ceramic restorations and implant-supported crowns.
Clinical report
A 69-year-old man presented complaining of his inability to masticate properly and sought esthetic improvement. He wanted “a solution with dental implants (fixed or removable) in a short time and without many surgeries.” He had worn a 15-year-old ill-fitting removable partial denture and presented with extensive dental caries on some abutment teeth, localized bleeding on probing, and deep pocket depths in the maxilla. Tooth wear and caries were observed on the mandibular posterior teeth (Fig. 1). Fixed and removable options were discussed, and he elected to receive a 4-implant-retained maxillary overdenture and mandibular anterior veneers and posterior implant-supported crowns to replace the missing teeth.
The maxillary teeth and the mandibular second premolars and right first molar were deemed nonrestorable because of caries and periodontal disease and were extracted. An interim maxillary complete denture was delivered. After scaling and root planning, he complied with the hygiene maintenance and proceeded with the implant placement. A computed tomography (CT) scan was made with a barium sulfate template to evaluate the suitability of both arches for implants, and a software program (CoDiagnostiX; Dental Wings GmbH) was used for virtual implant planning. Eight weeks after the extractions, 4 implants were placed in the maxilla (Standard Regular Neck Tissue Level; Institut Straumann AG) at the maxillary right (4.1×10 mm) and left lateral (4.1×12 mm) and the maxillary right (4.1×12 mm) and left first premolar sites (4.1×12 mm) with a static computer-aided implant surgery protocol, In the mandible, 4.1×10-mm dental implants (Standard Regular Neck Tissue Level; Institut Straumann AG) were placed at the right first and second premolar and the left first molar sites.
After a healing period of 8 weeks, a second-stage surgery in the maxilla was performed, and the implant stability quotient (ISQ) values of all implants were greater than 75. Definitive, fixture-level, open-tray impressions on both arches were made with an elastomeric impression material (Identium medium/light; Kettenbach GmbH & Co) in a custom tray. The interarch relationship records were made with a maxillary base plate and a wax occlusion rim (Megatray; Megadenta Dental products GmbH) and a facebow transfer. Both impressions were poured in Type IV dental stone (Elite Stone; Zhermack GmbH), and the definitive casts were mounted in a semiadjustable articulator (Condylator; Gerber Condylator GmbH). A diagnostic tooth arrangement (SR Phonares II; Ivoclar AG) was evaluated clinically to verify vertical dimension, phonetics, function, and esthetics. The definitive casts and diagnostic prostheses were sent to a dental laboratory technician. The diagnostic tooth arrangement was used in designing the maxillary framework and to evaluate the space for the implant attachments (Fig. 2). The definitive PEKK (PEKKTON-Ivory; Cendres+Métaux SA) framework and the wax maxillary crowns were fabricated in a 5-axis milling machine (S2 milling machine; vhf Camfacture AG) and evaluated intraorally (Fig. 3). The fit of the framework was evaluated by using the 1-screw test,
and wax crowns were evaluated for occlusion and esthetics. The crowns were pressed in lithium disilicate (Livento press; Cendres+Métaux SA), and the anterior crowns were veneered (Soprano; Cendres+Métaux SA). After glazing and polishing, the crowns and the overdenture attachment housings (CM-LOC; Cendres+Métaux SA) were cemented to the framework with an autopolymerizing composite resin cement (Multilink Hybrid Abutment; Ivoclar AG) (Fig. 4). The gingiva was reproduced by layering a light-polymerizing composite resin (SR Nexco; Ivoclar AG). The mandibular anterior veneers, the onlay on the left second molar, and the screw-retained posterior crowns were pressed in lithium disilicate (Livento press; Cendres+Métaux SA) (Fig. 4).
Figure 2Computer-aided design of maxillary overdenture. A, Virtual tooth arrangement. B, PEKK framework. C, Single crowns on virtual PEKK framework. PEKK, polyetherketoneketone.
The overdenture attachments (CM-LOC; Cendres+Métaux SA) and mandibular screw-retained crowns were tightened to 35 Ncm with a torque wrench, and the screw access holes were plugged with polytetrafluoroethylene tape and light-polymerizing composite resin (Tetric Evoceram; Ivoclar AG). The mandibular ceramic restorations were cemented with resin cement (Variolink Esthetic DC; Ivoclar AG) (Figs. 4, 5). The occlusion was adjusted, and the adjusted surfaces were polished by using a ceramic polishing kit (Kit 1440; Jota AG). He was satisfied with the function and esthetics at the 2-year follow-up. No biologic or technical complications were identified (Fig. 5B).
Figure 5After delivery of restorations. A, Frontal view. B, Panoramic radiograph at 2-year follow-up.
Implant overdenture bases have been commonly fabricated in acrylic resin supported with a cobalt-chromium framework; however, debonding, chipping, and wear have been reported, which may be extensive in patients with parafunctional habits.
Lithium disilicate crowns luted to a polymer framework veneered with pink acrylic or composite resin avoid the complications with acrylic resin denture base and denture teeth. Chipping and occlusal wear of the lithium disilicate crowns may have been minimized in the presented patient, as they were used in opposing arches; acrylic resin denture teeth could have debonded or worn.
However, long-term studies are needed before recommending PEKK for patients with parafunctional habits.
Stud attachments are commonly used to retain implant overdentures; however, they are susceptible to wear, with increased implant angulation and cyclic dislodgement.
The attachments used in the presented report had PEKK inserts.
The short-term outcomes with complete-arch implant-retained PEEK-acrylic resin prostheses have been evaluated, and 100% implant and 98% prosthetic survival rates were reported.
Loss of veneer adhesion, chipping, and screw loosening were reported, but the authors concluded that this material combination may be a valid option; however, long-term validation is required.
The use of high-performance polymers for fixed implant prostheses requires the use of titanium bases, as some complications were noted when titanium bases were not used.
Short-term report of an ongoing prospective cohort study evaluating the outcome of full-arch implant-supported fixed hybrid polyetheretherketone-acrylic resin prostheses and the all-on-four concept.
In the present report, a favorable outcome was achieved with a high-performance polymer framework and lithium disilicate ceramic restorations. However, results may vary depending on the situation of the treated patient, and clinical studies that evaluate the long-term outcomes in multiple situations are needed. The use of PEKK may require a learning curve, but a skilled dental laboratory technician can improve the esthetic outcomes dramatically when it is combined with recently developed materials which enable shading and surface characterization. Nevertheless, proper layering of the gingiva may require experience. After 2 years of service, no biologic or technical complications were observed, and he reported an improvement in his quality of life. Although the combined materials are more expensive than acrylic resin overdentures because the prosthetic design files are stored electronically, prostheses can be remilled if remakes are required.
Summary
A maxillary implant-retained PEKK overdenture framework with lithium disilicate crowns and mandibular tooth- or implant-supported ceramic restorations was used to treat a complex intraoral situation. This treatment enabled favorable outcomes in 2 years, and the material combinations used for the overdenture may be alternatives to conventional materials. Although the outcomes after 2 years were satisfactory, clinical trials are needed to evaluate the long-term performance of the combinations of materials used.
Acknowledgments
The authors thank Cendres+Métaux (Biel, Switzerland) for the material supply and technical support. The authors also thank Mr Daniel Roder (dental technician, Cendres+Métaux) and all dental technicians involved in the fabrication of presented patients’ prostheses: Patrick Zimmermann, Dominik Mäder, Gabriel Willauer, and Erwin Eitler (Zahnmanufaktur Dental Laboratory, Bern, Switzerland).
References
Sadowsky S.J.
Zitzmann N.U.
Protocols for the maxillary implant overdenture: a systematic review.
The influence of prosthetic material on implant and prosthetic survival of implant-supported fixed complete dentures: a systematic review and meta-analysis.
Comparative in vitro study of the bond strength of composite to carbon fiber versus ceramic to cobalt-chromium alloys frameworks for fixed dental prostheses.
Short-term report of an ongoing prospective cohort study evaluating the outcome of full-arch implant-supported fixed hybrid polyetheretherketone-acrylic resin prostheses and the all-on-four concept.
Treatment of a mandibular discontinuity defect by using a fibula free flap and an implant-supported fixed complete denture fabricated with a PEKK framework: a clinical report.
A speech bulb prosthesis for a soft palate defect with a polyetherketoneketone (PEKK) framework fabricated by multiple digital techniques: a clinical report.
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