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A technique for indirect fabrication of an implant-supported, screw-retained, fixed provisional restoration in the esthetic zone
A technique for indirect fabrication of an implant-supported, screw-retained, fixed provisional restoration in the esthetic zone Wei-Shao Lin, DDS,a and Carlo Ercoli, DDSb University of Rochester, Eastman Institute for Oral Health, Rochester, NY This article describes an alternative technique for the fabrication of an implant-supported, screw-retained, fixed provisional restoration in the esthetic zone. After an implant-level impression is made with a polyether impression material, the provisional restoration is fabricated indirectly. This technique is easy, saves time, and has economic advantages, while maintaining color stability and esthetic properties for the provisional restoration. It may be contraindicated for severely misaligned implants that require extensive reduction of the implant temporary abutments and denture teeth laminates. (J Prosthet Dent 2009;102:393-396) Implant-supported provisional restorations have advantages for dental implant treatment.1-3 Provisional restorations help confirm the design (screw retained or cement retained, abutment selection), esthetics, and phonetics of definitive restorations. In addition, the oral hygiene and periimplant soft tissue response of the patient can be monitored. Any need for modifying the soft tissue contour at the pontic areas can also be confirmed. Furthermore, provisional restorations facilitate clear communication between the patient, dentist, and dental technician. Patients may view and evaluate the definitive restorative result and assist in guiding the modifications for the definitive restoration. Once the desired results have been achieved with the provisional restoration, the necessary information can be easily transferred to the laboratory with buccal/facial indexes and clinical photographs. There are numerous techniques for fabricating implant-supported provisional restorations.4-7 They may be fabricated intraorally, directly on the implant components, or indirectly in the laboratory. One technique commonly used for conventional fixed prosthodontics employs a clear ma-
trix form, which can be used for both the direct and indirect methods.8,9 This matrix is designed to shape the acrylic resin into a provisional restoration based on the diagnostic waxing. The matrix is filled with provisional acrylic resin material and placed onto the definitive cast with provisional implant cylinders connected to the cast. The cast can be placed into a pressure pot for processing. The matrix is removed and definitive contouring is performed. The potential danger of using this technique intraorally is that acrylic resin may accidentally flow into the screw-access channels and increase the difficulty of removing the provisional restoration. Another popular technique is the indirect heat-processed provisional technique, which provides excellent fit, function, esthetics, and durability.6 The full-contour waxing, connected to implant temporary abutments and implant analogs, is invested in dental stone. After the wax is boiled out, heat-polymerizing provisional acrylic resin material is added to the stone mold and processed. With this technique, the desired provisional contours developed in the wax pattern can be accurately reproduced in the processed restoration. This article
Resident, Division of Prosthodontics. Associate Professor, Chair and Program Director, Division of Prosthodontics.
a
b
Lin and Ercoli
describes an alternative, time-saving, indirect fabrication technique for implant-supported screw-retained fixed provisional restorations.
TECHNIQUE 1. Perform a thorough examination of the esthetics and phonetics of the patient at the initial visit (Fig. 1). 2. Make the implant-level impression with polyether impression material (Impregum; 3M ESPE AG, Seefeld, Germany), and pour the impression using a type IV dental stone (ResinRock; Whip Mix Corp, Louisville, Ky) with implant analogs (Nobel Biocare USA, Yorba Linda, Calif ) in place. Articulate the definitive cast and the opposing cast in a semi-adjustable articulator (Hanau Modular Articulator System; Whip Mix Corp) with a face-bow transfer and an interocclusal centric relation record (Fig. 2). 3. Arrange the denture teeth (Portrait IPN; Dentsply Trubyte, York, Pa) according to the esthetic and phonetic requirements. Make the facial matrix with laboratory vinyl polysiloxane putty material (Sil-Tech; Ivoclar Vivadent AG, Schaan, Liechtenstein) around the facial surface of the arrangement of the teeth to preserve
394
Volume 102 Issue 6
1 Preexisting condition with failing fixed partial denture retained with maxillary right second premolar, central incisor, and maxillary left lateral incisor as provisional restorations after 6 dental implants were placed.
2 Definitive implant and opposing casts articulated.
3 Temporary abutments prepared facially and occlusally using facial putty matrix as reference. Adequate space (3-4 mm) exists between matrix and temporary abutments.
4 Positioned facial matrix with denture teeth laminates on definitive cast.
the spatial orientation of the denture teeth. 4. Attach temporary abutments (Temporary Abutment Non-Engaging; Nobel Biocare USA) with corresponding dental implant analogs (Nobel Biocare USA) on the definitive cast, and prepare the temporary abutments facially and occlusally, using the facial matrix as the reference. Ensure that there is adequate space (3-4 mm) between the facial matrix and the temporary abutments (Fig. 3). 5. Prepare the denture teeth with carbide rotary cutting instruments (Coarse Staggered Toothing H251GE; Brasseler USA, Savannah, Ga) to a thickness of 1.5 mm, and form denture teeth laminates. Note
that the facial surfaces of the denture teeth should remain intact. Make retention features with round carbide rotary cutting instruments (US No. 6; Brasseler USA) on the lingual surface of the denture teeth. Abrade the lingual surfaces of the denture teeth with a dental airborne-particleabrasion unit (Gobi-2 Fine Blasting Unit; Wassermann Dental-Maschinen GmbH, Hamburg, Germany) using 50-um aluminum oxide particles under 30 psi pressure to clean the surface of denture teeth laminates and to increase the mechanical retention. Steam clean all of the prepared denture laminates until no residual wax remains from the teeth arrangement procedure. 6. Attach all prepared denture
The Journal of Prosthetic Dentistry
teeth laminates with the cyanoacrylate (3M Scotch Super Glue; 3M ESPE, St. Paul, Minn) in the correct positions in the facial matrix, and reposition the facial matrix on the definitive cast. Maintain at least 1 mm of space between the temporary abutments and denture teeth laminates inside the facial matrix to allow proper flow of autopolymerizing acrylic resin (Jet Tooth Shade Acrylic; Lang Dental Mfg Co, Wheeling, Ill), and reprepare the temporary abutments or denture teeth laminates if proper space cannot be achieved (Fig. 4). 7. Remove the facial matrix and the temporary abutments from the definitive cast, and maintain them in the same order. Use light-polymerizing composite resin opaque mate-
Lin and Ercoli
395
December 2009 rial (Sinfony Indirect Lab Composite; 3M ESPE) to mask the gray shade on the facial side of the temporary abutments. 8. Apply separating agent (AlCote; Dentsply Trubyte) on the definitive cast evenly, and reassemble the temporary abutments and facial matrix with proper positioning. Place plastic sprues (Hollow Plastic Sprue; Handler Mfg, Westfield, NJ) in the temporary abutment screw-access openings, and use the monomer from the autopolymerizing acrylic resin (Jet Tooth Shade Acrylic; Lang Dental Mfg Co) to wet the denture teeth and temporary abutments. Mix the autopolymerizing acrylic resin (Jet Tooth Shade Acrylic; Lang Dental Mfg Co) and apply it on the palatal side of the facial matrix. The acrylic resin mix should cover all of the temporary abutments. Place the definitive cast in the pressure pot (Acridense VI Pneumatic Curing Unit; GC America, Inc, Alsip, Ill) in warm water to increase the strength and reduce the porosity of the material.10 9. Remove excess acrylic resin from the polymerized provisional fixed partial denture with rotary cutting instruments (Coarse Staggered Toothing H251GE and Flexible Serrated Diamond Disc 946.11; Brasseler USA). Polish the polymerized provisional fixed partial denture with flour of pumice. Evaluate the junction integrity between temporary abutments and the autopolymerizing acrylic resin, and add additional autopolymerizing acrylic resin with the sprinkleon method in defective areas.1 Apply pink-shaded light-polymerizing resin (Sinfony Indirect Lab Composite; 3M ESPE) on the areas with soft tissue defects to achieve proper contours for the eventual definitive fixed partial denture (Fig. 5). 10. Make any necessary adjustments, and secure the completed, implant-supported, screw-retained, provisional fixed partial prosthesis in place (Fig. 6).
Lin and Ercoli
5 Finished and polished provisional fixed partial denture.
6 Extracted remaining maxillary right central incisor and left lateral incisor. Implant-supported, screw-retained, provisional fixed partial prosthesis in position.
DISCUSSION Several direct and indirect provisionalization techniques have been described in the literature. With the direct technique, autopolymerized provisional restorations can be fabricated without the need for an implant-level impression. Laboratory steps are thereby eliminated, and the cost of the procedure is reduced.4,5 With the indirect technique, the heatprocessed provisional restoration is fabricated from a wax pattern developed on mounted casts, and the precise occlusion can be established. The heat-processed restoration is more color stable, less porous, and more wear resistant, enhancing the esthetics and serviceability of the FPD.6,7 This technique described is an alternative indirect technique for the fabrication of an implant-support-
ed, screw-retained, provisional fixed partial denture. Screw-retained provisional restorations eliminate the possibility of having provisional cement present in the periimplant tissue and prevent inflammation caused by excess residual cement. The indirect technique allows more control and precision, and autopolymerizing acrylic resin is easier and requires less time to use than heat-polymerizing acrylic resin. In addition, using the denture teeth laminates allows longterm color stability and esthetics to be achieved for the provisional restorations. The described technique may be contraindicated for severely misaligned implants that require extensive reduction of the temporary abutments and denture teeth laminates. In particular, when dental implants are misplaced toward the facial surface,
396
Volume 102 Issue 6 access holes may have to be placed at the incisal edge or the facial surface, which will compromise esthetics and function. An implant-level impression must be made and laboratory procedures are involved; therefore, the cost is more than for the direct technique. In addition, the lingual and occlusal surfaces of the provisional restoration require further adjustment to achieve the desired anatomic morphology.
SUMMARY An alternative for the fabrication of an implant-supported, screw-retained, fixed provisional restoration in the esthetic zone has been described. This technique allows for an easier and less time-consuming laboratory procedure because autopolymerizing acrylic resin is used; in addition, long-
term color stability and esthetics are maintained because the denture teeth serve as the laminates. Therefore, this technique may decrease laboratory expenses, yet still allow desirable esthetic results to be achieved.
REFERENCES 1. Moscovitch MS, Saba S. The use of a provisional restoration in implant dentistry: a clinical report. Int J Oral Maxillofac Implants 1996;11:395-9. 2. Santosa RE. Provisional restoration options in implant dentistry. Aust Dent J 2007;52:234-42. 3. Lewis S, Parel S, Faulkner R. Provisional implant-supported fixed restorations. Int J Oral Maxillofac Implants 1995;10:319-25. 4. Proussaefs P. The use of healing abutments for the fabrication of cement-retained, implant-supported provisional prostheses. J Prosthet Dent 2002;87:333-5. 5. Chaimattayompol N, Emtiaz S, Woloch MM. Transforming an existing fixed provisional prosthesis into an implant-supported fixed provisional prosthesis with the use of healing abutments. J Prosthet Dent 2002;88:96-9.
6. alZallal M, Morgano SM. The implantsupported, heat-processed provisional fixed partial denture. Am J Dent 1991;4:260-4. 7. Ganddini MR, Tallents RH, Ercoli C, Ganddini R. Technique for fabricating a cementretained single-unit implant-supported provisional restoration in the esthetic zone. J Prosthet Dent 2005;94:296-8. 8. Kökat AM, Akça K. Fabrication of a screwretained fixed provisional prosthesis supported by dental implants. J Prosthet Dent 2004;91:293-7. 9. Binon P. Provisional fixed restorations supported by osseointegrated implants in partially edentulous patients. Int J Oral Maxillofac Implants 1987;2:173-8. 10.Donovan TE, Hurst RG, Campagni WV. Physical properties of acrylic resin polymerized by four different techniques. J Prosthet Dent 1985;54:522-4. Corresponding author: Dr Wei-Shao Lin Division of Prosthodontics, University of Rochester Eastman Institute for Oral Health 625 Elmwood Ave, Box 683 Rochester, NY 14620 Fax: 585-244-8772 E-mail: [email protected] Copyright © 2009 by the Editorial Council for The Journal of Prosthetic Dentistry.
Noteworthy Abstracts of the Current Literature Masticatory performance, maximum occlusal force, and occlusal contact area in patients with bilaterally missing molars and distal extension removable partial dentures Aras K, Hasanreisoglu U, Shinogaya T. Int J Prosthodont 2009;22:204–9. Purpose: The aim of this study was to compare the masticatory performance, maximum occlusal force, and occlusal contact area of subjects with bilaterally missing molars, treated either with the shortened dental arch (SDA) concept or with distal extension removable partial dentures (RPDs), during a 1-year follow-up. Materials and Methods: This study included three groups of 10 subjects each, in which SDA and RPD groups displayed bilateral molar loss in the mandible. Subjects with complete natural dentition (CD) served as the control group. Masticatory performance was evaluated by the multiple sieve method. Standard cubes (edge length: 8 mm, 0.9 g) shaped from a high viscosity polysiloxane molding material (Zetaplus, Zhermack) were used as the test food. Maximum occlusal force (N) and occlusal contact area (mm2) were evaluated using dental prescale films. Results: No statistically significant differences regarding masticatory performance between the groups or evaluation periods were demonstrated. In the RPD group, masticatory performance with and without prostheses showed no significant differences. SDA patients showed significantly lower contact area and occlusal force than both the CD and RPD groups (P < .05). Conclusion: SDA can be an alternative to distal extension RPDs with respect to masticatory performance in subjects with bilaterally missing molars in one dental arch, despite remarkable reductions in maximum occlusal force and occlusal contact area. Reprinted with permission of Quintessence Publishing.
The Journal of Prosthetic Dentistry
Lin and Ercoli
trix form, which can be used for both the direct and indirect methods.8,9 This matrix is designed to shape the acrylic resin into a provisional restoration based on the diagnostic waxing. The matrix is filled with provisional acrylic resin material and placed onto the definitive cast with provisional implant cylinders connected to the cast. The cast can be placed into a pressure pot for processing. The matrix is removed and definitive contouring is performed. The potential danger of using this technique intraorally is that acrylic resin may accidentally flow into the screw-access channels and increase the difficulty of removing the provisional restoration. Another popular technique is the indirect heat-processed provisional technique, which provides excellent fit, function, esthetics, and durability.6 The full-contour waxing, connected to implant temporary abutments and implant analogs, is invested in dental stone. After the wax is boiled out, heat-polymerizing provisional acrylic resin material is added to the stone mold and processed. With this technique, the desired provisional contours developed in the wax pattern can be accurately reproduced in the processed restoration. This article
Resident, Division of Prosthodontics. Associate Professor, Chair and Program Director, Division of Prosthodontics.
a
b
Lin and Ercoli
describes an alternative, time-saving, indirect fabrication technique for implant-supported screw-retained fixed provisional restorations.
TECHNIQUE 1. Perform a thorough examination of the esthetics and phonetics of the patient at the initial visit (Fig. 1). 2. Make the implant-level impression with polyether impression material (Impregum; 3M ESPE AG, Seefeld, Germany), and pour the impression using a type IV dental stone (ResinRock; Whip Mix Corp, Louisville, Ky) with implant analogs (Nobel Biocare USA, Yorba Linda, Calif ) in place. Articulate the definitive cast and the opposing cast in a semi-adjustable articulator (Hanau Modular Articulator System; Whip Mix Corp) with a face-bow transfer and an interocclusal centric relation record (Fig. 2). 3. Arrange the denture teeth (Portrait IPN; Dentsply Trubyte, York, Pa) according to the esthetic and phonetic requirements. Make the facial matrix with laboratory vinyl polysiloxane putty material (Sil-Tech; Ivoclar Vivadent AG, Schaan, Liechtenstein) around the facial surface of the arrangement of the teeth to preserve
394
Volume 102 Issue 6
1 Preexisting condition with failing fixed partial denture retained with maxillary right second premolar, central incisor, and maxillary left lateral incisor as provisional restorations after 6 dental implants were placed.
2 Definitive implant and opposing casts articulated.
3 Temporary abutments prepared facially and occlusally using facial putty matrix as reference. Adequate space (3-4 mm) exists between matrix and temporary abutments.
4 Positioned facial matrix with denture teeth laminates on definitive cast.
the spatial orientation of the denture teeth. 4. Attach temporary abutments (Temporary Abutment Non-Engaging; Nobel Biocare USA) with corresponding dental implant analogs (Nobel Biocare USA) on the definitive cast, and prepare the temporary abutments facially and occlusally, using the facial matrix as the reference. Ensure that there is adequate space (3-4 mm) between the facial matrix and the temporary abutments (Fig. 3). 5. Prepare the denture teeth with carbide rotary cutting instruments (Coarse Staggered Toothing H251GE; Brasseler USA, Savannah, Ga) to a thickness of 1.5 mm, and form denture teeth laminates. Note
that the facial surfaces of the denture teeth should remain intact. Make retention features with round carbide rotary cutting instruments (US No. 6; Brasseler USA) on the lingual surface of the denture teeth. Abrade the lingual surfaces of the denture teeth with a dental airborne-particleabrasion unit (Gobi-2 Fine Blasting Unit; Wassermann Dental-Maschinen GmbH, Hamburg, Germany) using 50-um aluminum oxide particles under 30 psi pressure to clean the surface of denture teeth laminates and to increase the mechanical retention. Steam clean all of the prepared denture laminates until no residual wax remains from the teeth arrangement procedure. 6. Attach all prepared denture
The Journal of Prosthetic Dentistry
teeth laminates with the cyanoacrylate (3M Scotch Super Glue; 3M ESPE, St. Paul, Minn) in the correct positions in the facial matrix, and reposition the facial matrix on the definitive cast. Maintain at least 1 mm of space between the temporary abutments and denture teeth laminates inside the facial matrix to allow proper flow of autopolymerizing acrylic resin (Jet Tooth Shade Acrylic; Lang Dental Mfg Co, Wheeling, Ill), and reprepare the temporary abutments or denture teeth laminates if proper space cannot be achieved (Fig. 4). 7. Remove the facial matrix and the temporary abutments from the definitive cast, and maintain them in the same order. Use light-polymerizing composite resin opaque mate-
Lin and Ercoli
395
December 2009 rial (Sinfony Indirect Lab Composite; 3M ESPE) to mask the gray shade on the facial side of the temporary abutments. 8. Apply separating agent (AlCote; Dentsply Trubyte) on the definitive cast evenly, and reassemble the temporary abutments and facial matrix with proper positioning. Place plastic sprues (Hollow Plastic Sprue; Handler Mfg, Westfield, NJ) in the temporary abutment screw-access openings, and use the monomer from the autopolymerizing acrylic resin (Jet Tooth Shade Acrylic; Lang Dental Mfg Co) to wet the denture teeth and temporary abutments. Mix the autopolymerizing acrylic resin (Jet Tooth Shade Acrylic; Lang Dental Mfg Co) and apply it on the palatal side of the facial matrix. The acrylic resin mix should cover all of the temporary abutments. Place the definitive cast in the pressure pot (Acridense VI Pneumatic Curing Unit; GC America, Inc, Alsip, Ill) in warm water to increase the strength and reduce the porosity of the material.10 9. Remove excess acrylic resin from the polymerized provisional fixed partial denture with rotary cutting instruments (Coarse Staggered Toothing H251GE and Flexible Serrated Diamond Disc 946.11; Brasseler USA). Polish the polymerized provisional fixed partial denture with flour of pumice. Evaluate the junction integrity between temporary abutments and the autopolymerizing acrylic resin, and add additional autopolymerizing acrylic resin with the sprinkleon method in defective areas.1 Apply pink-shaded light-polymerizing resin (Sinfony Indirect Lab Composite; 3M ESPE) on the areas with soft tissue defects to achieve proper contours for the eventual definitive fixed partial denture (Fig. 5). 10. Make any necessary adjustments, and secure the completed, implant-supported, screw-retained, provisional fixed partial prosthesis in place (Fig. 6).
Lin and Ercoli
5 Finished and polished provisional fixed partial denture.
6 Extracted remaining maxillary right central incisor and left lateral incisor. Implant-supported, screw-retained, provisional fixed partial prosthesis in position.
DISCUSSION Several direct and indirect provisionalization techniques have been described in the literature. With the direct technique, autopolymerized provisional restorations can be fabricated without the need for an implant-level impression. Laboratory steps are thereby eliminated, and the cost of the procedure is reduced.4,5 With the indirect technique, the heatprocessed provisional restoration is fabricated from a wax pattern developed on mounted casts, and the precise occlusion can be established. The heat-processed restoration is more color stable, less porous, and more wear resistant, enhancing the esthetics and serviceability of the FPD.6,7 This technique described is an alternative indirect technique for the fabrication of an implant-support-
ed, screw-retained, provisional fixed partial denture. Screw-retained provisional restorations eliminate the possibility of having provisional cement present in the periimplant tissue and prevent inflammation caused by excess residual cement. The indirect technique allows more control and precision, and autopolymerizing acrylic resin is easier and requires less time to use than heat-polymerizing acrylic resin. In addition, using the denture teeth laminates allows longterm color stability and esthetics to be achieved for the provisional restorations. The described technique may be contraindicated for severely misaligned implants that require extensive reduction of the temporary abutments and denture teeth laminates. In particular, when dental implants are misplaced toward the facial surface,
396
Volume 102 Issue 6 access holes may have to be placed at the incisal edge or the facial surface, which will compromise esthetics and function. An implant-level impression must be made and laboratory procedures are involved; therefore, the cost is more than for the direct technique. In addition, the lingual and occlusal surfaces of the provisional restoration require further adjustment to achieve the desired anatomic morphology.
SUMMARY An alternative for the fabrication of an implant-supported, screw-retained, fixed provisional restoration in the esthetic zone has been described. This technique allows for an easier and less time-consuming laboratory procedure because autopolymerizing acrylic resin is used; in addition, long-
term color stability and esthetics are maintained because the denture teeth serve as the laminates. Therefore, this technique may decrease laboratory expenses, yet still allow desirable esthetic results to be achieved.
REFERENCES 1. Moscovitch MS, Saba S. The use of a provisional restoration in implant dentistry: a clinical report. Int J Oral Maxillofac Implants 1996;11:395-9. 2. Santosa RE. Provisional restoration options in implant dentistry. Aust Dent J 2007;52:234-42. 3. Lewis S, Parel S, Faulkner R. Provisional implant-supported fixed restorations. Int J Oral Maxillofac Implants 1995;10:319-25. 4. Proussaefs P. The use of healing abutments for the fabrication of cement-retained, implant-supported provisional prostheses. J Prosthet Dent 2002;87:333-5. 5. Chaimattayompol N, Emtiaz S, Woloch MM. Transforming an existing fixed provisional prosthesis into an implant-supported fixed provisional prosthesis with the use of healing abutments. J Prosthet Dent 2002;88:96-9.
6. alZallal M, Morgano SM. The implantsupported, heat-processed provisional fixed partial denture. Am J Dent 1991;4:260-4. 7. Ganddini MR, Tallents RH, Ercoli C, Ganddini R. Technique for fabricating a cementretained single-unit implant-supported provisional restoration in the esthetic zone. J Prosthet Dent 2005;94:296-8. 8. Kökat AM, Akça K. Fabrication of a screwretained fixed provisional prosthesis supported by dental implants. J Prosthet Dent 2004;91:293-7. 9. Binon P. Provisional fixed restorations supported by osseointegrated implants in partially edentulous patients. Int J Oral Maxillofac Implants 1987;2:173-8. 10.Donovan TE, Hurst RG, Campagni WV. Physical properties of acrylic resin polymerized by four different techniques. J Prosthet Dent 1985;54:522-4. Corresponding author: Dr Wei-Shao Lin Division of Prosthodontics, University of Rochester Eastman Institute for Oral Health 625 Elmwood Ave, Box 683 Rochester, NY 14620 Fax: 585-244-8772 E-mail: [email protected] Copyright © 2009 by the Editorial Council for The Journal of Prosthetic Dentistry.
Noteworthy Abstracts of the Current Literature Masticatory performance, maximum occlusal force, and occlusal contact area in patients with bilaterally missing molars and distal extension removable partial dentures Aras K, Hasanreisoglu U, Shinogaya T. Int J Prosthodont 2009;22:204–9. Purpose: The aim of this study was to compare the masticatory performance, maximum occlusal force, and occlusal contact area of subjects with bilaterally missing molars, treated either with the shortened dental arch (SDA) concept or with distal extension removable partial dentures (RPDs), during a 1-year follow-up. Materials and Methods: This study included three groups of 10 subjects each, in which SDA and RPD groups displayed bilateral molar loss in the mandible. Subjects with complete natural dentition (CD) served as the control group. Masticatory performance was evaluated by the multiple sieve method. Standard cubes (edge length: 8 mm, 0.9 g) shaped from a high viscosity polysiloxane molding material (Zetaplus, Zhermack) were used as the test food. Maximum occlusal force (N) and occlusal contact area (mm2) were evaluated using dental prescale films. Results: No statistically significant differences regarding masticatory performance between the groups or evaluation periods were demonstrated. In the RPD group, masticatory performance with and without prostheses showed no significant differences. SDA patients showed significantly lower contact area and occlusal force than both the CD and RPD groups (P < .05). Conclusion: SDA can be an alternative to distal extension RPDs with respect to masticatory performance in subjects with bilaterally missing molars in one dental arch, despite remarkable reductions in maximum occlusal force and occlusal contact area. Reprinted with permission of Quintessence Publishing.
The Journal of Prosthetic Dentistry
Lin and Ercoli