Design concepts of a removable partial dental prosthesis with implant-supported abutments Stephanie Yeung, DDS,a Winston W. L. Chee, DDS,b and Arman Torbati, DDSc Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, Calif A clinical report is presented that describes the restoration of a severe anterior maxillary ridge defect and pneumatized sinuses with a rotation-path partial removable dental prosthesis and implant-supported abutments. Other treatment options were considered and rejected based on patient preferences and limitations, which included avoiding invasive surgeries. The principles of integrating fixed and removable prosthesis design were applied. However, the clasp design was modified to take into account the direct bone-to-implant contact of the abutments. An esthetic and functional outcome was obtained without any overly invasive surgery. (J Prosthet Dent 2014;-:---) One goal of dental reconstruction is to regain durable function and esthetics as similar to natural teeth as possible. For an patient who is edentulous, 5 treatment options can be considered: no treatment, mucosa-supported removable dental prostheses (RDP), implant-retained RDP, fixed detachable prostheses, and metal ceramic fixed dental prostheses. Each treatment option has unique advantages and limitations with respect to space, implant distribution, and implant number.1-5 For the patient presented, implantsupported restorations coupled with a rotation-path RDP were selected to obtain the best esthetics and function possible. This allowed implantsupported fixed restorations to provide function and also to support and retain a rotation-path RDP, which would restore esthetics and function in a severely atrophic anterior maxilla. A rotation-path RDP can provide an esthetic outcome when a patient presents with a Kennedy class IV classification by eliminating the display of clasps.6-8 Several design variations are available, although the general requirements are 2 surveyed planes, rigid retention in the chosen guide planes, and retentive clasps in the nonvisible areas.9 a
With rotation-path RDPs, care must be taken during framework design, casting, and polishing to maintain an intimate contact between the undercut areas used for retention adjacent to the edentulous span.10 The contour and location of the rest seats, undercut positions, rotational axis, arch shape and length, and tooth tilt also may provide obstacles in seating or retaining the prosthesis. In addition, difficulty with seating may arise if the residual anterior ridge is large.11 In this particular situation, the clinician (S.Y.) is in control of the factors previously listed because the posterior restorations will be fabricated with the design of the rotationpath RDP already predetermined.
(Fig. 1).12,13 Intraorally, the patient had a large maxillary torus and malpositioned teeth remaining, which included the following teeth: maxillary first and second premolars, maxillary left first and second molars, mandibular canines and first premolars, and mandibular right second premolar and
CLINICAL REPORT A healthy 55-year-old woman presented to the advanced prosthodontics department at the Herman Ostrow School of Dentistry of the University of Southern California experiencing difficulty with mastication and dissatisfaction with her present dental esthetics. With her existing prostheses in place, the patient displayed more of her mandibular teeth than maxillary teeth
1 Pretreatment frontal view without existing removable dental prosthesis.
Former resident, Advanced Prosthodontics. Ralph and Jean Bleak Professor of Restorative Dentistry; Director, Implant Dentistry; Co-Director, Advanced Prosthodontics. c Associate Professor, Advanced Prosthodontics. b
Yeung et al
2
Volume first molar. All remaining teeth exhibited caries, mobility, and/or defective restorations. The patient reported that her missing teeth had been extracted during childhood and adolescence, which probably led to the advanced resorption observed in both the maxillary and mandibular arches. In addition, the patient reported that she had undergone maxillary advancement surgery at a local hospital approximately 1 year earlier at the request of her previous dental provider to compensate for the resorption of her anterior maxilla. The goal of this surgery, which still left a deficient maxillary ridge, could not be discerned from her history, and an attempt to contact the previous provider for more information failed. Because of the numbness of the soft tissues left in the surgical areas, the patient refused any further surgical procedures. The diagnosis for this patient was American College of Prosthodontists (ACP) class III, generalized moderatesevere bone loss, and Siebert class 3 bone loss in all edentulous areas.14,15 The interarch space was approximately 20 mm between the edentulous ridges, with the vertical dimension maintained by 3 posterior occluding pairs (Fig. 2). The maxillary RDP compensated for the anterior deficiency with a significant amount of acrylic resin, which measured approximately 11 mm from the incisive papilla to the incisal edges of the central incisors. A cone-beam computed tomographic, panoramic, and complete-mouth series of radiographs revealed widening of the periodontal ligament in the maxillary teeth, pneumatized sinuses, and generalized severe bone loss.16 Steel metal plating attached bilaterally to the patient’s maxillary alveolar bone and zygoma were evident radiographically (Fig. 3). The anterior edentulous maxilla was resorbed to the nasal spine. In the posterior maxilla, the edentulous sites had approximately 3 to 4 mm of vertical bone height, with adequate horizontal width. In the mandible, the anterior portion had resorbed into a thin spiny ridge, and, in the posterior
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Issue
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2 Pretreatment frontal interocclusal view in maximum intercuspation.
3 Pretreatment panoramic radiograph with inferior alveolar nerve and tooth positions marked. areas, bone had resorbed to within 3 to 4 mm of the inferior alveolar canal. Upon reviewing these findings with the patient, she reiterated that she did not wish to undergo any surgeries beyond extractions and implant placement. When taking into account the patient’s chief complaints and stipulations regarding surgeries, a preliminary treatment plan was developed. She had a history of a Le Fort osteotomy, but there was sufficient evidence of positive implant success rates in similar patients.17-19 The paucity of bone for implant placement created a situation in which the removal of all remaining teeth would be necessary for implant placement. This decision was made with a risk and cost-benefit analysis with consideration of the clinical findings of a widened periodontal ligament, bone loss, defective restorations, and malpositioned teeth. Informed consent was obtained from the patient, after which all teeth,
The Journal of Prosthetic Dentistry
with the exception of the mandibular right first molar, were removed and restored with an immediate maxillary complete denture and immediate mandibular resin-based partial dental prosthesis with a wrought clasp that encircled the mandibular right first molar; this tooth was retained to serve as a mandibular surgical index but was extracted after all surgeries had been completed. The definitive restoration planned for the mandible was a fixeddetachable dental prosthesis. The maxilla was to be made into a Kennedy class IV classification arch by placing splinted metal ceramic implant restorations in the posterior area, then fabricating an anterior rotation-path RDP. After 4 months of uneventful postextraction healing and the patient’s approval of the tooth positioning in her interim prostheses, radiographic guides were fabricated by duplicating the removable prostheses in clear
Yeung et al
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2014
orthodontic resin with gutta percha markers through each tooth. Upon evaluation of the cone-beam computed tomography (Fig. 3), implants were placed with the aid of a surgical guide converted from the radiographic guide. Implant placement was completed in 2 appointments. In the first session, 4.0 10-mm parallel implants (Osseotite External Hex; Biomet 3i) were placed into 5 mandibular incisor, canine, and premolar sites; the 5 implants were immediately loaded by converting the mandibular removable denture into a resin-based, fixed-detachable appliance. In the second session, bilateral sinus lifts with the osteotome technique created vertical space for 2 implants on the day of implant placement; no additional grafting material was used.20 Parallel implants (4.0 10 mm) (Osseotite External Hex) were placed into maxillary premolar and molar sites. A 5.0 10 mm parallel implant (Osseotite External Hex) was placed into the maxillary right second molar site because of questionable primary stability during surgery. Because of the Type IV bone, the maxillary implants were all buried, and the maxillary complete denture was adjusted and relined with tissue conditioner (ViscoGel; Dentsply Professional) to fit. After 6 months of healing, all 7 implants in the maxilla were found to be well integrated. The 6 implants with the best distribution were selected for restoration; an abutment healing cap was placed on the superfluous maxillary right first molar implant to allow tissue relapse. An implant-level impression was made by using pick-up impression copings (hexed; Biomet 3i) for the appropriate platform sizes with medium- and heavy-body polyvinyl siloxane (Extrude; Kerr Corp). With the help of jigs fabricated from acrylic resin plates (GC Pattern; GC America) on temporary cylinders (4.0 or 5.0 mm, nonhexed; Biomet 3i) attached to implants and a Pana-Mount facebow jaw transfer, occlusal registration was made with green modeling plastic impression compound (Kerr Impression Compound; Kerr Corp); the casts were then
Yeung et al
3 mounted onto a semiadjustable articulator (Panadent PCH; Panadent Corp). Definitive wax patterns were completed with tooth positions and contours by using the patient’s provisional complete denture as guidance. With a tentative design of the rotation-path RDP and a surveyor, the wax patterns were modified to present undercuts for rigid retention of the prosthesis in the anterior and conventional retentive areas for clasps in the posterior. Appropriate placement of these retentive areas were confirmed by surveying the cast in 2 positions: the first was in a position to eliminate the undercut areas, and the second was in a neutral treatment position with the occlusal plane horizontal (Fig. 4).21 Before cutting back the wax patterns for framework casting, the wax patterns were duplicated with condensation silicone (Lab Putty; Coltène/Whaldent) to fabricate interim restorations made of polymethyl methacrylate resin (Jet; Lang Dental) reflective of the definitive restorations (Fig. 5). These interim restorations were then attached to the definitive cast. The definitive cast with restorations was duplicated to fabricate the interim RDP from acrylic denture teeth and denture base resin (Characterized Lucitone Denture Base Resin; Dentsply Intl). The definitive posterior restorations were surveyed after each processing step before fabrication of the anterior
4 Cut-back posterior segments on surveyor in neutral tilt, revealing planned undercuts in anterior. RDP framework to ensure that no intended design features were altered.22 The wax patterns were cast in highnoble white Type IV alloy (Argedent 40; Argen), after which framework seating was verified intraorally before finishing with feldspathic ceramic (Creation Dental Porcelain; Jensen Dental). After confirming the fit, contours, and occlusion of the finished posterior restorations, an impression of the seated units was made with a border molded custom impression tray
5 Posterior units pressed in polymethyl methacrylate (Jet; Lang Dental) and interim partial denture made of acrylic resin denture teeth and denture base resin (Characterized Lucitone Denture Base Resin; Dentsply Intl).
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Volume
6 Wax pattern framework on refractory cast. with light and heavy-body polyvinyl siloxane impression material (Extrude; Kerr Corp). The RDP framework wax pattern on the refractory cast was evaluated to correct any errors before casting in cobalt-chromium alloy (NobilStar Ultra; Nobilium) (Fig. 6).23 Detours from the conventional clasp design included the use of occlusal access to the implant screws as rest seats and the omission of components used for encirclement, reciprocation, and bracing because no orthodontic movement was possible with implantsupported abutments. When the RDP wax pattern was returned to the laboratory for casting, the technician was instructed to wax out the proximal plates before electropolishing the framework to ensure an intimate fit of this part of the framework to the abutments; this would be paramount in retaining the RDP.10 On the return of the RDP, the framework seating was evaluated with chloroform and rouge, and then adjusted as necessary. The maxillary and mandibular tooth position was evaluated to verify occlusion, esthetics, and phonetics. On confirmation of the functional aspects and acceptance by the patient of the esthetics, the maxillary and mandibular acrylic restorations were processed. All definitive prostheses were delivered simultaneously. All implant screws were tightened to 35 Ncm with square gold screws (Biomet 3i). These were retightened 1 week after delivery before sealing with composite resin.24 Where the screw
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Issue
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7 Intraoral view of definitive maxillary prostheses.
access holes were rest seats, their fit was formed by applying petroleum jelly before molding unpolymerized resin and light polymerizing.25 The patient was pleased with the outcome, although it took some repetition and instructional reinforcement over 2 to 3 weeks until she could master the insertion and removal of the RDP (Figs. 7, 8).
SUMMARY This is a report on the reconstruction of a patient with a failing dentition who had functional and esthetic deficits when using fixed implant supported restorations and a partial RDP in the maxilla and a fixed detachable fixed dental prosthesis in the mandible. These restorations were selected due to limitations of the presenting osseous anatomy, which could not be altered due to the patient’s refusal to undergo any grafting procedures and a preference for fixed restorations for as many units as possible. Fixed restorations were accomplished in all areas except the anterior maxilla due to a severely deficient ridge form; for this segment, a rotation-path RDP was designed, with supporting abutments fabricated to integrate with the RDP. Because all abutments for this RDP were implantsupported, a novel clasp design was used in the clasp in the posterior area. The end result met all of the esthetic and functional demands of the patient, while requiring no surgery beyond extraction and implant placement.
The Journal of Prosthetic Dentistry
8 Frontal views after delivery of all definitive restorations.
REFERENCES 1. Sadowsky SJ. Treatment considerations for maxillary implant overdentures: a systematic review. J Prosthet Dent 2007;97:340-8. 2. Slot W, Raghoebar GM, Vissink A, Huddlestone Slater JJ, Meijer HJA. A systematic review of implant-supported maxillary overdentures after a mean observation period of at least 1 year. J Clin Periodontol 2010; 37:98-110. 3. Schnitman PA. The profile prosthesis: an aesthetic fixed implant-supported restoration for the resorbed maxilla. Pract Periodont Aesthet Dent 1998;11:143-51. 4. Weinberg LA. The biomechanics of force distribution in implant-supported prostheses. Int J Oral Maxillofac Implants 1993; 8:19-31.
Yeung et al
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2014
5. Landa JS. The torus palatines and its management in full denture construction. J Prosthet Dent 1951;1:236-43. 6. Jacobsen TE, Krol AJ. Rotational path removable partial denture design. J Prosthet Dent 1982;48:370-6. 7. King GE, Barco MT, Olson RJ. Inconspicuous retention for removable partial dentures. J Prosthet Dent 1978;39:505-7. 8. Firtell DN, Jacobsen TE. Removable partial dentures with rotational paths of insertion: problem analysis. J Prosthet Dent 1983;50:8-15. 9. Schwartz RS, Murchison DG. Design variations of the rotational path removable partial denture. J Prosthet Dent 1987; 58:336-8. 10. Brudvik JS, Reimers D. The tooth-removable partial denture interface. J Prosthet Dent 1992;68:924-7. 11. Ivanhoe JR. Laboratory considerations in rotational path removable partial dentures. J Prosthet Dent 2000;94:470-2. 12. Desai S, Upadhyay M, Nanda R. Dynamic smile analysis: changes with age. Am J Orthod Dentofacial Orthop 2009;136:310. e1-310.e10; discussion 310-1. 13. Tjan AH, Miller GD, The JG. Some esthetic factors in a smile. J Prosthet Dent 1984;51: 24-8.
Yeung et al
5 14. McGarry TJ, Nimmo A, Skiba JF, Ahlstrom RJ, Smith CR, Koumjian JH, et al. Classification system for partial edentulism. J Prosthodont 2002;11:181-93. 15. Seibert JS. Reconstruction of deformed partially edentulous ridges using full thickness onlay grafts: part I e technique and wound healing. Compend Contin Educ Dent 1983;4:437-53. 16. Armitage GC. Classifying periodontal disease: a long-standing dilemma. Periodontol 2000 2002;30:9-23. 17. Hallman M, Mordenfeld A, Strandkvist T. A retrospective 5-year follow-up study of two different titanium implant surfaces used after interpositional bone grafting for reconstruction of the atrophic edentulous maxilla. Clin Impl Dent Rel Res 2005;7:121-6. 18. Siebert JW, Angrigiani C, McCarthy JG, Longaker MT. Blood supply of the Le Fort I maxillary segment: an anatomic study. Plast Reconstr Surg 1997;100:843-51. 19. Sailer HF. A new method of inserting endosseous implants in totally atrophic maxillae. J Craniomaxillofac Surg 1989;17: 299-305. 20. Summers RB. A new concept in maxillary implant surgery: the osteotome technique. Compendium 1994;15:154-6.
21. King GE. Dual-path design for removable partial denture. J Prosthet Dent 1978;39: 392-5. 22. Preston JD. Preventing ceramic failures when integrating fixed and removable prostheses. Dent Clin North Am 1979;23:37-52. 23. Frank RP. Evaluating refractory cast wax-ups for removable partial dentures. J Prosthet Dent 1976;35:388-92. 24. Shigley J, Mischke C, Brown T. Standard handbook of machine design. 2nd ed. New York: McGraw-Hill Professional; 1996. 25. Stern MA, Brudvik JS, Frank RP. Clinical evaluation of removable partial denture rest seat adaptation. J Prosthet Dent 1985;53: 658-62. Corresponding author: Dr Stephanie Yeung Advanced Prosthodontics University of Southern California, School of Dentistry 925, W 34th St, Room 102 Los Angeles, CA 90089 E-mail: [email protected] Copyright ª 2014 by the Editorial Council for The Journal of Prosthetic Dentistry.
With rotation-path RDPs, care must be taken during framework design, casting, and polishing to maintain an intimate contact between the undercut areas used for retention adjacent to the edentulous span.10 The contour and location of the rest seats, undercut positions, rotational axis, arch shape and length, and tooth tilt also may provide obstacles in seating or retaining the prosthesis. In addition, difficulty with seating may arise if the residual anterior ridge is large.11 In this particular situation, the clinician (S.Y.) is in control of the factors previously listed because the posterior restorations will be fabricated with the design of the rotationpath RDP already predetermined.
(Fig. 1).12,13 Intraorally, the patient had a large maxillary torus and malpositioned teeth remaining, which included the following teeth: maxillary first and second premolars, maxillary left first and second molars, mandibular canines and first premolars, and mandibular right second premolar and
CLINICAL REPORT A healthy 55-year-old woman presented to the advanced prosthodontics department at the Herman Ostrow School of Dentistry of the University of Southern California experiencing difficulty with mastication and dissatisfaction with her present dental esthetics. With her existing prostheses in place, the patient displayed more of her mandibular teeth than maxillary teeth
1 Pretreatment frontal view without existing removable dental prosthesis.
Former resident, Advanced Prosthodontics. Ralph and Jean Bleak Professor of Restorative Dentistry; Director, Implant Dentistry; Co-Director, Advanced Prosthodontics. c Associate Professor, Advanced Prosthodontics. b
Yeung et al
2
Volume first molar. All remaining teeth exhibited caries, mobility, and/or defective restorations. The patient reported that her missing teeth had been extracted during childhood and adolescence, which probably led to the advanced resorption observed in both the maxillary and mandibular arches. In addition, the patient reported that she had undergone maxillary advancement surgery at a local hospital approximately 1 year earlier at the request of her previous dental provider to compensate for the resorption of her anterior maxilla. The goal of this surgery, which still left a deficient maxillary ridge, could not be discerned from her history, and an attempt to contact the previous provider for more information failed. Because of the numbness of the soft tissues left in the surgical areas, the patient refused any further surgical procedures. The diagnosis for this patient was American College of Prosthodontists (ACP) class III, generalized moderatesevere bone loss, and Siebert class 3 bone loss in all edentulous areas.14,15 The interarch space was approximately 20 mm between the edentulous ridges, with the vertical dimension maintained by 3 posterior occluding pairs (Fig. 2). The maxillary RDP compensated for the anterior deficiency with a significant amount of acrylic resin, which measured approximately 11 mm from the incisive papilla to the incisal edges of the central incisors. A cone-beam computed tomographic, panoramic, and complete-mouth series of radiographs revealed widening of the periodontal ligament in the maxillary teeth, pneumatized sinuses, and generalized severe bone loss.16 Steel metal plating attached bilaterally to the patient’s maxillary alveolar bone and zygoma were evident radiographically (Fig. 3). The anterior edentulous maxilla was resorbed to the nasal spine. In the posterior maxilla, the edentulous sites had approximately 3 to 4 mm of vertical bone height, with adequate horizontal width. In the mandible, the anterior portion had resorbed into a thin spiny ridge, and, in the posterior
-
Issue
-
2 Pretreatment frontal interocclusal view in maximum intercuspation.
3 Pretreatment panoramic radiograph with inferior alveolar nerve and tooth positions marked. areas, bone had resorbed to within 3 to 4 mm of the inferior alveolar canal. Upon reviewing these findings with the patient, she reiterated that she did not wish to undergo any surgeries beyond extractions and implant placement. When taking into account the patient’s chief complaints and stipulations regarding surgeries, a preliminary treatment plan was developed. She had a history of a Le Fort osteotomy, but there was sufficient evidence of positive implant success rates in similar patients.17-19 The paucity of bone for implant placement created a situation in which the removal of all remaining teeth would be necessary for implant placement. This decision was made with a risk and cost-benefit analysis with consideration of the clinical findings of a widened periodontal ligament, bone loss, defective restorations, and malpositioned teeth. Informed consent was obtained from the patient, after which all teeth,
The Journal of Prosthetic Dentistry
with the exception of the mandibular right first molar, were removed and restored with an immediate maxillary complete denture and immediate mandibular resin-based partial dental prosthesis with a wrought clasp that encircled the mandibular right first molar; this tooth was retained to serve as a mandibular surgical index but was extracted after all surgeries had been completed. The definitive restoration planned for the mandible was a fixeddetachable dental prosthesis. The maxilla was to be made into a Kennedy class IV classification arch by placing splinted metal ceramic implant restorations in the posterior area, then fabricating an anterior rotation-path RDP. After 4 months of uneventful postextraction healing and the patient’s approval of the tooth positioning in her interim prostheses, radiographic guides were fabricated by duplicating the removable prostheses in clear
Yeung et al
-
2014
orthodontic resin with gutta percha markers through each tooth. Upon evaluation of the cone-beam computed tomography (Fig. 3), implants were placed with the aid of a surgical guide converted from the radiographic guide. Implant placement was completed in 2 appointments. In the first session, 4.0 10-mm parallel implants (Osseotite External Hex; Biomet 3i) were placed into 5 mandibular incisor, canine, and premolar sites; the 5 implants were immediately loaded by converting the mandibular removable denture into a resin-based, fixed-detachable appliance. In the second session, bilateral sinus lifts with the osteotome technique created vertical space for 2 implants on the day of implant placement; no additional grafting material was used.20 Parallel implants (4.0 10 mm) (Osseotite External Hex) were placed into maxillary premolar and molar sites. A 5.0 10 mm parallel implant (Osseotite External Hex) was placed into the maxillary right second molar site because of questionable primary stability during surgery. Because of the Type IV bone, the maxillary implants were all buried, and the maxillary complete denture was adjusted and relined with tissue conditioner (ViscoGel; Dentsply Professional) to fit. After 6 months of healing, all 7 implants in the maxilla were found to be well integrated. The 6 implants with the best distribution were selected for restoration; an abutment healing cap was placed on the superfluous maxillary right first molar implant to allow tissue relapse. An implant-level impression was made by using pick-up impression copings (hexed; Biomet 3i) for the appropriate platform sizes with medium- and heavy-body polyvinyl siloxane (Extrude; Kerr Corp). With the help of jigs fabricated from acrylic resin plates (GC Pattern; GC America) on temporary cylinders (4.0 or 5.0 mm, nonhexed; Biomet 3i) attached to implants and a Pana-Mount facebow jaw transfer, occlusal registration was made with green modeling plastic impression compound (Kerr Impression Compound; Kerr Corp); the casts were then
Yeung et al
3 mounted onto a semiadjustable articulator (Panadent PCH; Panadent Corp). Definitive wax patterns were completed with tooth positions and contours by using the patient’s provisional complete denture as guidance. With a tentative design of the rotation-path RDP and a surveyor, the wax patterns were modified to present undercuts for rigid retention of the prosthesis in the anterior and conventional retentive areas for clasps in the posterior. Appropriate placement of these retentive areas were confirmed by surveying the cast in 2 positions: the first was in a position to eliminate the undercut areas, and the second was in a neutral treatment position with the occlusal plane horizontal (Fig. 4).21 Before cutting back the wax patterns for framework casting, the wax patterns were duplicated with condensation silicone (Lab Putty; Coltène/Whaldent) to fabricate interim restorations made of polymethyl methacrylate resin (Jet; Lang Dental) reflective of the definitive restorations (Fig. 5). These interim restorations were then attached to the definitive cast. The definitive cast with restorations was duplicated to fabricate the interim RDP from acrylic denture teeth and denture base resin (Characterized Lucitone Denture Base Resin; Dentsply Intl). The definitive posterior restorations were surveyed after each processing step before fabrication of the anterior
4 Cut-back posterior segments on surveyor in neutral tilt, revealing planned undercuts in anterior. RDP framework to ensure that no intended design features were altered.22 The wax patterns were cast in highnoble white Type IV alloy (Argedent 40; Argen), after which framework seating was verified intraorally before finishing with feldspathic ceramic (Creation Dental Porcelain; Jensen Dental). After confirming the fit, contours, and occlusion of the finished posterior restorations, an impression of the seated units was made with a border molded custom impression tray
5 Posterior units pressed in polymethyl methacrylate (Jet; Lang Dental) and interim partial denture made of acrylic resin denture teeth and denture base resin (Characterized Lucitone Denture Base Resin; Dentsply Intl).
4
Volume
6 Wax pattern framework on refractory cast. with light and heavy-body polyvinyl siloxane impression material (Extrude; Kerr Corp). The RDP framework wax pattern on the refractory cast was evaluated to correct any errors before casting in cobalt-chromium alloy (NobilStar Ultra; Nobilium) (Fig. 6).23 Detours from the conventional clasp design included the use of occlusal access to the implant screws as rest seats and the omission of components used for encirclement, reciprocation, and bracing because no orthodontic movement was possible with implantsupported abutments. When the RDP wax pattern was returned to the laboratory for casting, the technician was instructed to wax out the proximal plates before electropolishing the framework to ensure an intimate fit of this part of the framework to the abutments; this would be paramount in retaining the RDP.10 On the return of the RDP, the framework seating was evaluated with chloroform and rouge, and then adjusted as necessary. The maxillary and mandibular tooth position was evaluated to verify occlusion, esthetics, and phonetics. On confirmation of the functional aspects and acceptance by the patient of the esthetics, the maxillary and mandibular acrylic restorations were processed. All definitive prostheses were delivered simultaneously. All implant screws were tightened to 35 Ncm with square gold screws (Biomet 3i). These were retightened 1 week after delivery before sealing with composite resin.24 Where the screw
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Issue
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7 Intraoral view of definitive maxillary prostheses.
access holes were rest seats, their fit was formed by applying petroleum jelly before molding unpolymerized resin and light polymerizing.25 The patient was pleased with the outcome, although it took some repetition and instructional reinforcement over 2 to 3 weeks until she could master the insertion and removal of the RDP (Figs. 7, 8).
SUMMARY This is a report on the reconstruction of a patient with a failing dentition who had functional and esthetic deficits when using fixed implant supported restorations and a partial RDP in the maxilla and a fixed detachable fixed dental prosthesis in the mandible. These restorations were selected due to limitations of the presenting osseous anatomy, which could not be altered due to the patient’s refusal to undergo any grafting procedures and a preference for fixed restorations for as many units as possible. Fixed restorations were accomplished in all areas except the anterior maxilla due to a severely deficient ridge form; for this segment, a rotation-path RDP was designed, with supporting abutments fabricated to integrate with the RDP. Because all abutments for this RDP were implantsupported, a novel clasp design was used in the clasp in the posterior area. The end result met all of the esthetic and functional demands of the patient, while requiring no surgery beyond extraction and implant placement.
The Journal of Prosthetic Dentistry
8 Frontal views after delivery of all definitive restorations.
REFERENCES 1. Sadowsky SJ. Treatment considerations for maxillary implant overdentures: a systematic review. J Prosthet Dent 2007;97:340-8. 2. Slot W, Raghoebar GM, Vissink A, Huddlestone Slater JJ, Meijer HJA. A systematic review of implant-supported maxillary overdentures after a mean observation period of at least 1 year. J Clin Periodontol 2010; 37:98-110. 3. Schnitman PA. The profile prosthesis: an aesthetic fixed implant-supported restoration for the resorbed maxilla. Pract Periodont Aesthet Dent 1998;11:143-51. 4. Weinberg LA. The biomechanics of force distribution in implant-supported prostheses. Int J Oral Maxillofac Implants 1993; 8:19-31.
Yeung et al
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2014
5. Landa JS. The torus palatines and its management in full denture construction. J Prosthet Dent 1951;1:236-43. 6. Jacobsen TE, Krol AJ. Rotational path removable partial denture design. J Prosthet Dent 1982;48:370-6. 7. King GE, Barco MT, Olson RJ. Inconspicuous retention for removable partial dentures. J Prosthet Dent 1978;39:505-7. 8. Firtell DN, Jacobsen TE. Removable partial dentures with rotational paths of insertion: problem analysis. J Prosthet Dent 1983;50:8-15. 9. Schwartz RS, Murchison DG. Design variations of the rotational path removable partial denture. J Prosthet Dent 1987; 58:336-8. 10. Brudvik JS, Reimers D. The tooth-removable partial denture interface. J Prosthet Dent 1992;68:924-7. 11. Ivanhoe JR. Laboratory considerations in rotational path removable partial dentures. J Prosthet Dent 2000;94:470-2. 12. Desai S, Upadhyay M, Nanda R. Dynamic smile analysis: changes with age. Am J Orthod Dentofacial Orthop 2009;136:310. e1-310.e10; discussion 310-1. 13. Tjan AH, Miller GD, The JG. Some esthetic factors in a smile. J Prosthet Dent 1984;51: 24-8.
Yeung et al
5 14. McGarry TJ, Nimmo A, Skiba JF, Ahlstrom RJ, Smith CR, Koumjian JH, et al. Classification system for partial edentulism. J Prosthodont 2002;11:181-93. 15. Seibert JS. Reconstruction of deformed partially edentulous ridges using full thickness onlay grafts: part I e technique and wound healing. Compend Contin Educ Dent 1983;4:437-53. 16. Armitage GC. Classifying periodontal disease: a long-standing dilemma. Periodontol 2000 2002;30:9-23. 17. Hallman M, Mordenfeld A, Strandkvist T. A retrospective 5-year follow-up study of two different titanium implant surfaces used after interpositional bone grafting for reconstruction of the atrophic edentulous maxilla. Clin Impl Dent Rel Res 2005;7:121-6. 18. Siebert JW, Angrigiani C, McCarthy JG, Longaker MT. Blood supply of the Le Fort I maxillary segment: an anatomic study. Plast Reconstr Surg 1997;100:843-51. 19. Sailer HF. A new method of inserting endosseous implants in totally atrophic maxillae. J Craniomaxillofac Surg 1989;17: 299-305. 20. Summers RB. A new concept in maxillary implant surgery: the osteotome technique. Compendium 1994;15:154-6.
21. King GE. Dual-path design for removable partial denture. J Prosthet Dent 1978;39: 392-5. 22. Preston JD. Preventing ceramic failures when integrating fixed and removable prostheses. Dent Clin North Am 1979;23:37-52. 23. Frank RP. Evaluating refractory cast wax-ups for removable partial dentures. J Prosthet Dent 1976;35:388-92. 24. Shigley J, Mischke C, Brown T. Standard handbook of machine design. 2nd ed. New York: McGraw-Hill Professional; 1996. 25. Stern MA, Brudvik JS, Frank RP. Clinical evaluation of removable partial denture rest seat adaptation. J Prosthet Dent 1985;53: 658-62. Corresponding author: Dr Stephanie Yeung Advanced Prosthodontics University of Southern California, School of Dentistry 925, W 34th St, Room 102 Los Angeles, CA 90089 E-mail: [email protected] Copyright ª 2014 by the Editorial Council for The Journal of Prosthetic Dentistry.
