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Table of Contents   
CASE REPORT  
Year : 2012  |  Volume : 23  |  Issue : 1  |  Page : 97-100
Flexible resins in the rehabilitation of maxillectomy patient


1 Department of Prosthodontics, Narayana Dental College, Nellore, India
2 Department of Prosthodontics, Government Dental College, Hyderabad, Andhra Pradesh, India

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Date of Submission11-Jan-2011
Date of Decision19-Apr-2011
Date of Acceptance11-Jul-2011
Date of Web Publication26-Jul-2012
 

   Abstract 

Surgical resection is an established and common method for treatment of maxillofacial tumors. Such intervening surgery in this region may involve the destruction of antral, nasal, or orbital contents and jaws. Normally, the end result is a defect which may affect speech, swallowing, mastication and facial appearance. Prosthodontic restoration of functions and facial form is an excellent method in the replacement of missing parts and restoration of contour. Pertinent research in materials, designs and methods have resulted in whole array of possible prosthess that can be provided to meet specific patient needs. This case report describes the fabrication of definitive obturator prosthesis made of flexible acrylic resin on a chrome cobalt base.

Keywords: Injection mould technique, maxillectomy, obturator, thermoplastic resin

How to cite this article:
Tannamala PK, Pulagam M, Pottem SR, Karnam S. Flexible resins in the rehabilitation of maxillectomy patient. Indian J Dent Res 2012;23:97-100

How to cite this URL:
Tannamala PK, Pulagam M, Pottem SR, Karnam S. Flexible resins in the rehabilitation of maxillectomy patient. Indian J Dent Res [serial online] 2012 [cited 2014 Sep 30];23:97-100. Available from: http://www.ijdr.in/text.asp?2012/23/1/97/99048
A maxillectomy is required if the tumor is very malignant histologically, or, if it either invades or involves the nasal cavity or paranasal sinus. Post-surgical maxillary defects predispose the patient to hyper-nasal speech, fluid leakage in the nasal cavity, impaired masticatory function, and, in some patients, various degrees of cosmetic deformity. [1] Prosthetic intervention, with a maxillary obturator prosthesis is necessary to restore the contours of the resected palate and to recreate the functional separation of the oral cavity and sinus and nasal cavities. Prosthetic intervention should occur at the time of surgical resection and will be necessary for the remainder of the patient's life. [2] The surgical and interim obturators are purely made of acrylic resins. Their primary role is to aid in healing during the recovery period and to shorten long-term convalescence and rehabilitation. It supports soft tissues, thus minimizing scar contracture, protects the wound from trauma and contamination with food debris. [3],[4] Three to four months after the surgery, after a thorough evaluation of healing and prognosis of tumor, definitive obturator prosthesis can be given.

One of the most recent advances in dental technology is the application of nylon-like materials for the fabrication of dental appliances. Since their introduction in the 1950s, there has been a continued interest in thermoplastic dental materials. [5] Thermoplastic resins are used for a broad variety of applications from removable flexible partial dentures, preformed partial denture clasps, fiber-reinforced fixed partial dentures, temporary crowns and bridges, provisional crowns and bridges, obturators and speech therapy appliances, orthodontic retainers and brackets, impression tray and border molding materials, occlusal splints, sleep apnea appliances, and implant abutments. [6]

The case report presented below describes the use of thermoplastic resin in the fabrication of definitive obturator prosthesis for prosthetic rehabilitation of maxillary defect following tumor resection.


   Case Report Top


An 18-year-old female patient reported to the department of Prosthodontics, Narayana Dental College and Hospital, Nellore, India, after undergoing inferior partial maxillectomy due to chondroblastic osteosarcoma. The patient was initially rehabilitated with surgical obturator at the time of surgery, followed by interim obturator for six months.

The intra-oral examination revealed a large defect on the left side of the maxilla and dentulous condition on the right side. The defect corresponded to Class II situation according to the Aramany Classification of defects [Figure 1]. [7]
Figure 1: Intraoral view of the defect

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Impressions of the maxillary and mandibular arches were made with irreversible hydrocolloid (Zelgan; Dentsply, India) taking care to block out the defect with petrolatum-laden gauge; diagnostic casts were prepared with dental stone (Gold stone; Asian chemicals, Rajkot, India) and diagnostic surveying done.

A definitive closed bulb obturator was planned as per the design principles given by Aramany in 1978 for Class II maxillary defects considering stability, retention and load distribution by the application of tripodal design. [8] Embrasure clasps were planned on premolar and molars, indirect retention was achieved by canine rest and I bar clasp was planned on the maxillary left central incisor. [8],[9] Since the patient expressed concern for show of metal on the incisor, retention on incisor was planned by using flexible thermoplastic resin (Valplast Int. Corp, New York, USA) instead of I bar clasp.

Mouth preparation was done as per treatment plan. Border molding was done with low-fusing compound (DPI Pinnacle tracing sticks, Mumbai, India) on custom-made tray. The defect area was molded with putty addition silicon (Elite HD+; Zhermack, Italy) and master impression was made with light body addition silicon (Elite HD+; Zhermack, Italy) [Figure 2].
Figure 2: Final impression made with light body addition silicone impression material

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The master cast was prepared with die stone (Ultra rock; Kalabhai, India) [Figure 3], surveying and block-out of undercuts on master cast were done. Master cast was duplicated with reversible hydrocolloid and refractory cast was obtained. The wax frame work was fabricated, sprued, invested and casting was done with Cr-Co alloy (Solidur Co-Cr; Yeti Dental, Germany). Finished and polished framework [Figure 4] was tried in the patient's mouth for fit. Jaw relations were recorded, teeth setting was done and wax try-in performed. Processing of the Waxed - up denture was done using injection molding technique with specially designed aluminum flask. Wax - up denture along with cast was invested in the bottom half of the flask with dental stone. After investing media was fully set, sprues were attached to the wax - up denture.
Figure 3: Master cast showing defect measuring 2 × 3 cm2

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Figure 4: Master cast with finished framework

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Separating medium was applied in the bottom half of the investment material, then upper half was closed and filled with second pour of investment material and allowed to set. Dewaxing was carried out in hot water bath. After the flask was cooled, the teeth were removed and prepared for mechanical retention. Mechanical retention was obtained by diatoric holes with medium drills. Then teeth were cemented in place with Val-cement (Valplast Int. Corp, New York, USA). The mold was insulated using a special agent (Acrylic Sep; Bredent, Germany).

The flask was positioned carefully under the super injector by placing the sprue end of the flask with the shaft of the super injector. Furnace and melting cylinder were preheated to 220°C for 20 min. The selected valplast resin tube (Valplast Int. Corp, New York, USA) was placed into the melting cylinder and heated for 11 min according to the manufacturer's instructions. The melting cylinder with resin tube was removed carefully in horizontal position and placed over the sprue end of the flask. The lever of the super injector was turned with rapid and steady motion and maintained for 3bmin [Figure 5]. Flask was removed after disengaging from the press and bench-cooled for 30 min. The prosthesis was recovered after polymerization following which finishing and polishing done [Figure 6]. The prosthesis was inserted [Figure 7] and the patient was instructed about home care and prosthesis maintenance.
Figure 5: Special flask placed under super injector during processing

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Figure 6: Finished obturator with the flexible clasp in anterior region

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Figure 7: Flexible clasp on the incisors is pink in color like gums and built to curve around the necks of teeth

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   Discussion Top


Thermoplastic resins have been used in dentistry for over 50 years. Thermoplastic resins and co-polymers have many advantages over conventional powder or liquid resin systems. Thermoplastic resins tend to have predictable long-term performance. They are stable and resist thermal polymer unzipping. They also exhibit high creep resistance and high fatigue endurance as well as excellent wear characteristics and solvent resistance. Thermoplastic resins typically have very little or almost no free monomer in the material. A significant percentage of the population is allergic to free monomer and these materials offer a new safe treatment alternative for these individuals. [6],[10],[11],[12],[13] The disadvantage of these resins include gradual fading of denture base color, noticeable shift of prosthetic teeth during processing, air entrapment within the denture base material, poor bonding between the denture base material and acrylic resin teeth and technique sensitivity. [14]

Prosthetic rehabilitation of dentate maxillectomy patients is a lengthy and involved process. However, if attention is paid to the proper sequencing and details of treatment, it can be one of the most satisfying procedures. Aramany Class II defects generally provide a favorable situation when sound remaining teeth are present. This case report describes a tripodal removable prosthetic design. The patient expressed concern for the show of metal on the anterior teeth. A flexible and aesthetic retention of anterior teeth was planned by using thermoplastic resin. These resins are nearly unbreakable, pink-colored like gums, can be built quite thin, and can form not only the denture base but also the clasps. Since the clasps are built to curl around the necks of the teeth, they are practically undistinguishable from the gums. [5]


   Conclusion Top


Maxillofacial defects are highly individual and require the clinician to call upon all his knowledge and experience to fabricate a functional prosthesis. Without a definitive prosthesis, patients are not afforded the opportunity for complete rehabilitation. There are many individual presentations for acquired palatal deficiencies and varying challenges when providing patients with prosthetic rehabilitation. The restorative dentist has to be imaginative and innovative and adhere to the principles of rehabilitation while designing these prosthesis. [15],[16]

 
   References Top

1.Curtis TA, Beumer J III. Restoration of acquired hard palate defects: Etiology, disability, and rehabilitation. In: Beumer J, Curtis TA, Marunick MT (editors). Maxillofacial Rehabilitation: Prosthodontic and Surgical Considerations. St Louis: Ishiyaku EuroAmerica Inc; 1996. p. 225-84.  Back to cited text no. 1
    
2.Jacob RF. Clinical management of the edentulous maxillectomy patient. In: Taylor TD (editor). Clinical maxillofacial prosthetics. Chicago: Quintessence; 2000. p. 85-102.  Back to cited text no. 2
    
3.Loh HS, Tan PH. Prosthodontic management of maxillofacial defects after cancer surgery. Singpore Med J 1989;30:74-8.  Back to cited text no. 3
    
4.Haraguchi M, Mukohyama H, Taniguchi H. A simple method of fabricating interim obturator prosthesis by duplicating the existing teeth and palatal form. J Prothet Dent June 2006;95:469-72.  Back to cited text no. 4
    
5.Negrutiu M, Sinescu C, Sticlaru C, Davidescu A, Rominu M. The analysis of removable partial dentures with clasps made from thermoplastic and chemoplastic materials. A biomedical approach of the interface between clasps and denture. Eur Cell Mater 2007;13:20.  Back to cited text no. 5
    
6.Pusz A, Szymiczek M, Michalik K. Aging process influence on mechanical properties of polyamide-glass composites applied in dentistry. JAMME Jan 2010;38:49-55.  Back to cited text no. 6
    
7.Aramany MA. Basic principles of obturator design for partially edentulous patients. Part I: Classification. J Prosthet Dent 1978;40:554-7.  Back to cited text no. 7
    
8.Aramany MA. Basic principles of obturator design for partially edentulous patients. Part II: Design principles. J Prosthet Dent 1978;40:656-62.  Back to cited text no. 8
    
9.Parr GR. Prosthodontic principles in frame work design of maxillary obturator prosthesis. J Prosthet Dent 2005;93:405-11.  Back to cited text no. 9
    
10.Abuzar MA, Bellur S, Duong N, Kim BB, Lu P, Palfreyman N, et al. Evaluating surface roughness of a polyamide denture base material in comparison with poly (methyl methacrylate). J Oral Sci 2010;52:577-81.  Back to cited text no. 10
    
11.Yunus N, Rashid A, Azmi LL, Abu-Hassan MI. Some flexural properties of a nylon denture base polymer. J Oral Rehabil 2005;32:65-71.  Back to cited text no. 11
    
12.Takabayashi Y. Charesteristics of denture thermoplastic resins for non-metal clasp dentures. Dent Mater J 2010;29:353-61.  Back to cited text no. 12
    
13.Goiato MC, Santos DM, Haddad MF, Pesqueira AA. Effect of accelerated aging on the microhardness and color stability of flexible resins for dentures. Braz Oral Res 2010;24:114-9.  Back to cited text no. 13
    
14.Anusavice KJ. Phillips Science of Dental Materials, 11 th Ed. Philadelphia: WB Saunders Co; 1996. p. 736-7.  Back to cited text no. 14
    
15.Desjardins RP. Obturator prosthesis design for acquired maxillary defects. J Prosthet Dent 1978;39:424-35.  Back to cited text no. 15
    
16.Walter DJ. Obturators for acquired palatal defects. Dent Update 2005;32:277-84.  Back to cited text no. 16
    

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Correspondence Address:
Pavan Kumar Tannamala
Department of Prosthodontics, Narayana Dental College, Nellore
India
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DOI: 10.4103/0970-9290.99048

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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]



 

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    Abstract
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