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A technique for fabricating a hinged mandibular complete dental prosthesis with swing lock for a patient with microstomia
A technique for fabricating a hinged mandibular complete dental prosthesis with swing lock for a patient with microstomia Nakul Rathi, BDS, BBA,a Reza Heshmati, DDS, MPH, MS,b Burak Yilmaz, DDS, PhD,c and William Wilson, DTd The Ohio State University, College of Dentistry, Columbus, Ohio Microstomia is defined as an acquired or congenital condition involving a reduction of the oral aperture severe enough to compromise esthetics, nutrition, and quality of life. This clinical report describes a technique for fabricating a mandibular swinglock complete denture with a hinge for a patient with muscular dystrophy. A hinge in the midline allowed the denture to collapse. The collapsed denture could then be inserted into the mouth and locked into position. A sectional impression technique was used and the custom hinge was designed on the cobalt-chromium metal framework of the complete denture. The protocol presented can provide a viable treatment option for edentulous patients with microstomia. (J Prosthet Dent 2013;110:540-543) Microstomia is a condition in which the patient has an abnormally small oral orifice; it may result from the surgical
treatment of orofacial neoplasms, cleft lips, maxillofacial trauma, burns, radiotherapy, or other systemic disease.1
Muscular dystrophy is a group of inherited disorders that involve gradual muscle weakness and loss of muscle
1 A, Extraoral view of patient with microstomia and limited mouth opening. B, Sectional impression tray with indexing device. C, Impression tray evaluated intraorally. D, Definitive impression after sections were reassembled. a
Resident, Graduate Prosthodontics, Division of Restorative and Prosthetic Dentistry. Associate Professor, Division of Restorative and Prosthetic Dentistry. c Assistant Professor, Division of Restorative and Prosthetic Dentistry. d Dental Technician, Division of Restorative and Prosthetic Dentistry. b
The Journal of Prosthetic Dentistry
Rathi et al
December 2013
541
2 A, Wax pattern for framework with labial swing lock and lingual hinge. B, Cast Co-Cr framework C, Metal framework showing open swing lock and open hinge.
tissue.1 The main cause of muscular dystrophy is the impairment to properly create the functional protein dystrophin and dystrophin-associated protein complex by the cytoskeleton of the muscle tissue.1 Fabricating complete dentures for patients with microstomia presents difficulties at all stages, from the preliminary impressions to fabrication of the prostheses. It may even be impossible to make impressions and fabricate dentures by using conventional methods. Different impression methods and designs have been proposed including the use of orthodontic expansion screws to fabricate sectional trays, metal pins, and acrylic resin blocks to attach the sections of the impression trays, as well as flexible impression trays.2-6 Generally, sectional and collapsible dentures are used to provide such patients with a prosthesis.3-5
Rathi et al
This clinical report presents a modification of previously described methods used to fabricate mandibular impression trays and mandibular dentures for patients with microstomia. The treatment of a 32-year-old man with limited mouth opening (vertical approximately 25 mm, horizontal approximately 35 mm) due to muscular dystrophy is presented (Fig. 1A).
TECHNIQUE 1. Fabricate a light-polymerized polyurethane sectional custom tray (Triad TruTray; Densply Intl) from preliminary casts (Fig. 1B, C). 2. Make a definitive impression with sectional custom trays by using a medium-viscosity elastomeric material (Impregum Penta MB; 3M ESPE) (Fig. 1D). 3. Fit the sectional trays together by using resin blocks on the tray and
then index them in place with an indexing device. Draw fiduciary lines to help indexing. Pour the definitive cast in Type V gypsum (Die-Keen; Heraeus Kulzer) (Fig. 1B-D). 4. Duplicate the definitive cast after placing the wax relief and make a refractory cast (Niranium Good Earth Ethyl-Silicate Investment; CMP Industries LLC) (Fig. 2A) 5. Wax the framework with inlay wax (Corning Wax Co Inc). Incorporate a labial swing lock (Swing-Lock) in the waxing. Wax the hinge latch on the lingual midline around a metal hinge post (Nobil-Latch; Nobilium Co) (Fig. 2A). 6. Cast the metal framework from cobaltechromium dental alloy (NobilStar Ingot Alloy; Nobilium Co) (Fig. 2B). 7. Make the records with wax rims and wax bases on the foldable metal framework. Mount definitive casts
542
Volume 110 Issue 6
3 A, Light-body polyvinyl siloxane used to block out hinge during processing. B, Framework after boil-out. Swing lock labial latch secured in stone.
4 A, Prosthesis folded and maneuvered intraorally; open swing lock. B, Swing-lock latch used to stabilize prosthesis. C, Intraoral view of definitive hinged mandibular complete prosthesis.
on a semiadjustable articulator by using the maxillomandibular relationship records and facebow transfer (Fig. 2C). 8. Set the denture teeth (Trubyte; Dentsply Intl) and perform trial insertion.
9. Cover the swing lock with dental stone during processing. Inject light-body polyvinyl siloxane (VPS; Aquasil UltraExtra Light Body; Dentsply Intl) into the hinge on the midline to avoid incorporating the resin into the hinge (Fig. 3A, B).
The Journal of Prosthetic Dentistry
10. Process (Lucitone 199 Denture Resin; Dentsply Intl), finish, and polish the prosthesis for delivery. Educate the patient on how to hinge the prosthesis, insert it in the mouth (Fig. 3C), and latch the swing lock (Fig. 4B, C).
Rathi et al
December 2013
543
SUMMARY The resin block and indexing technique used for this patient with microstomia is a predictable method for fabricating sectional impression trays. A foldable, single-piece mandibular prosthesis for a patient with limited mouth opening is a successful treatment. However, the clinical and laboratory procedures are technique sensitive. In addition, patients should be educated about proper insertion and removal, and future maintenance and remakes, which may contribute to the increased cost of the prosthesis, may be necessary.
REFERENCES 1. Fauci L, Hauser K, Loscalzo J. Harrison’s principles of internal medicine. 18th ed. New York: McGraw-Hill; 2011. p. 2527-31. 2. Wahle JJ, Gardner LK, Fiebiger M. The mandibular swing-lock complete denture for patients with microstomia. J Prosthet Dent 1992;68:523-7. 3. Suzuki Y, Abe M, Hosoi T, Kurtz KS. Sectional collapsed denture for a partially edentulous patient with microstomia: a clinical report. J Prosthet Dent 2000;84:256-9. 4. Geckili O, Cilingir A, Bilgin T. Impression procedures and construction of a sectional denture for a patient with microstomia: a clinical report. J Prosthet Dent 2006;96:387-90. 5. Cura C, Cotert HS, User A. Fabrication of a sectional impression tray and sectional complete denture for a patient with microstomia and trismus: a clinical report. J Prosthet Dent 2003;89:540-3.
6. Alfano SG, Lemus FE. Fabrication of a unilateral oral commissure retractor. J Prosthet Dent 2012;108:398-400. Corresponding author: Dr Nakul Rathi Division of Restorative and Prosthetic Dentistry College of Dentistry The Ohio State University Columbus, OH 43210 E-mail: [email protected] Copyright ª 2013 by the Editorial Council for The Journal of Prosthetic Dentistry.
Access to The Journal of Prosthetic Dentistry Online is reserved for print subscribers! Full-text access to The Journal of Prosthetic Dentistry Online is available for all print subscribers. To activate your individual online subscription, please visit The Journal of Prosthetic Dentistry Online. Point your browser to http://www.journals. elsevierhealth.com/periodicals/ympr/home, follow the prompts to activate online access here, and follow the instructions. To activate your account, you will need your subscriber account number, which you can find on your mailing label ( note: the number of digits in your subscriber account number varies from 6 to 10). See the example below in which the subscriber account number has been circled. Sample mailing label
This is your subscription account number
Personal subscriptions to The Journal of Prosthetic Dentistry Online are for individual use only and may not be transferred. Use of The Journal of Prosthetic Dentistry Online is subject to agreement to the terms and conditions as indicated online.
Rathi et al
treatment of orofacial neoplasms, cleft lips, maxillofacial trauma, burns, radiotherapy, or other systemic disease.1
Muscular dystrophy is a group of inherited disorders that involve gradual muscle weakness and loss of muscle
1 A, Extraoral view of patient with microstomia and limited mouth opening. B, Sectional impression tray with indexing device. C, Impression tray evaluated intraorally. D, Definitive impression after sections were reassembled. a
Resident, Graduate Prosthodontics, Division of Restorative and Prosthetic Dentistry. Associate Professor, Division of Restorative and Prosthetic Dentistry. c Assistant Professor, Division of Restorative and Prosthetic Dentistry. d Dental Technician, Division of Restorative and Prosthetic Dentistry. b
The Journal of Prosthetic Dentistry
Rathi et al
December 2013
541
2 A, Wax pattern for framework with labial swing lock and lingual hinge. B, Cast Co-Cr framework C, Metal framework showing open swing lock and open hinge.
tissue.1 The main cause of muscular dystrophy is the impairment to properly create the functional protein dystrophin and dystrophin-associated protein complex by the cytoskeleton of the muscle tissue.1 Fabricating complete dentures for patients with microstomia presents difficulties at all stages, from the preliminary impressions to fabrication of the prostheses. It may even be impossible to make impressions and fabricate dentures by using conventional methods. Different impression methods and designs have been proposed including the use of orthodontic expansion screws to fabricate sectional trays, metal pins, and acrylic resin blocks to attach the sections of the impression trays, as well as flexible impression trays.2-6 Generally, sectional and collapsible dentures are used to provide such patients with a prosthesis.3-5
Rathi et al
This clinical report presents a modification of previously described methods used to fabricate mandibular impression trays and mandibular dentures for patients with microstomia. The treatment of a 32-year-old man with limited mouth opening (vertical approximately 25 mm, horizontal approximately 35 mm) due to muscular dystrophy is presented (Fig. 1A).
TECHNIQUE 1. Fabricate a light-polymerized polyurethane sectional custom tray (Triad TruTray; Densply Intl) from preliminary casts (Fig. 1B, C). 2. Make a definitive impression with sectional custom trays by using a medium-viscosity elastomeric material (Impregum Penta MB; 3M ESPE) (Fig. 1D). 3. Fit the sectional trays together by using resin blocks on the tray and
then index them in place with an indexing device. Draw fiduciary lines to help indexing. Pour the definitive cast in Type V gypsum (Die-Keen; Heraeus Kulzer) (Fig. 1B-D). 4. Duplicate the definitive cast after placing the wax relief and make a refractory cast (Niranium Good Earth Ethyl-Silicate Investment; CMP Industries LLC) (Fig. 2A) 5. Wax the framework with inlay wax (Corning Wax Co Inc). Incorporate a labial swing lock (Swing-Lock) in the waxing. Wax the hinge latch on the lingual midline around a metal hinge post (Nobil-Latch; Nobilium Co) (Fig. 2A). 6. Cast the metal framework from cobaltechromium dental alloy (NobilStar Ingot Alloy; Nobilium Co) (Fig. 2B). 7. Make the records with wax rims and wax bases on the foldable metal framework. Mount definitive casts
542
Volume 110 Issue 6
3 A, Light-body polyvinyl siloxane used to block out hinge during processing. B, Framework after boil-out. Swing lock labial latch secured in stone.
4 A, Prosthesis folded and maneuvered intraorally; open swing lock. B, Swing-lock latch used to stabilize prosthesis. C, Intraoral view of definitive hinged mandibular complete prosthesis.
on a semiadjustable articulator by using the maxillomandibular relationship records and facebow transfer (Fig. 2C). 8. Set the denture teeth (Trubyte; Dentsply Intl) and perform trial insertion.
9. Cover the swing lock with dental stone during processing. Inject light-body polyvinyl siloxane (VPS; Aquasil UltraExtra Light Body; Dentsply Intl) into the hinge on the midline to avoid incorporating the resin into the hinge (Fig. 3A, B).
The Journal of Prosthetic Dentistry
10. Process (Lucitone 199 Denture Resin; Dentsply Intl), finish, and polish the prosthesis for delivery. Educate the patient on how to hinge the prosthesis, insert it in the mouth (Fig. 3C), and latch the swing lock (Fig. 4B, C).
Rathi et al
December 2013
543
SUMMARY The resin block and indexing technique used for this patient with microstomia is a predictable method for fabricating sectional impression trays. A foldable, single-piece mandibular prosthesis for a patient with limited mouth opening is a successful treatment. However, the clinical and laboratory procedures are technique sensitive. In addition, patients should be educated about proper insertion and removal, and future maintenance and remakes, which may contribute to the increased cost of the prosthesis, may be necessary.
REFERENCES 1. Fauci L, Hauser K, Loscalzo J. Harrison’s principles of internal medicine. 18th ed. New York: McGraw-Hill; 2011. p. 2527-31. 2. Wahle JJ, Gardner LK, Fiebiger M. The mandibular swing-lock complete denture for patients with microstomia. J Prosthet Dent 1992;68:523-7. 3. Suzuki Y, Abe M, Hosoi T, Kurtz KS. Sectional collapsed denture for a partially edentulous patient with microstomia: a clinical report. J Prosthet Dent 2000;84:256-9. 4. Geckili O, Cilingir A, Bilgin T. Impression procedures and construction of a sectional denture for a patient with microstomia: a clinical report. J Prosthet Dent 2006;96:387-90. 5. Cura C, Cotert HS, User A. Fabrication of a sectional impression tray and sectional complete denture for a patient with microstomia and trismus: a clinical report. J Prosthet Dent 2003;89:540-3.
6. Alfano SG, Lemus FE. Fabrication of a unilateral oral commissure retractor. J Prosthet Dent 2012;108:398-400. Corresponding author: Dr Nakul Rathi Division of Restorative and Prosthetic Dentistry College of Dentistry The Ohio State University Columbus, OH 43210 E-mail: [email protected] Copyright ª 2013 by the Editorial Council for The Journal of Prosthetic Dentistry.
Access to The Journal of Prosthetic Dentistry Online is reserved for print subscribers! Full-text access to The Journal of Prosthetic Dentistry Online is available for all print subscribers. To activate your individual online subscription, please visit The Journal of Prosthetic Dentistry Online. Point your browser to http://www.journals. elsevierhealth.com/periodicals/ympr/home, follow the prompts to activate online access here, and follow the instructions. To activate your account, you will need your subscriber account number, which you can find on your mailing label ( note: the number of digits in your subscriber account number varies from 6 to 10). See the example below in which the subscriber account number has been circled. Sample mailing label
This is your subscription account number
Personal subscriptions to The Journal of Prosthetic Dentistry Online are for individual use only and may not be transferred. Use of The Journal of Prosthetic Dentistry Online is subject to agreement to the terms and conditions as indicated online.
Rathi et al