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 Table of Contents  
DENTAL SCIENCE - CASE REPORT
Year : 2013  |  Volume : 5  |  Issue : 6  |  Page : 201-203  

A laboratory silicone for preclinical training in ear prosthesis


Department of Prosthodontics, Sathyabama University Dental College and Hospital, Chennai, Tamil Nadu, India

Date of Submission16-May-2013
Date of Decision24-May-2013
Date of Acceptance24-May-2013
Date of Web Publication1-Jul-2013

Correspondence Address:
Vijay Anand
Department of Prosthodontics, Sathyabama University Dental College and Hospital, Chennai, Tamil Nadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0975-7406.114310

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   Abstract 

This article describes an industrial elastic silicone as a material for the laboratory fabrication of ear prosthesis. It has been tested for toxicity in lab animals by the SGS India Pvt. Ltd and approved as a material to pass the parameter of abnormal toxicity. This material therefore can be safely recommended for laboratory exercise to fabricate facial prosthesis. The high cost of the maxillo facial silicone materials prohibits their use for facial prosthesis in pre-clinical training of post-graduate students in maxillofacial prosthodontics. For this reason, pre-clinical laboratory exercise in facial prosthesis is inadequate. A few institutions use polymethyl methacrylate resins which are rigid and do not have elastic characteristics of silicone, which is used for facial defects. This cost-effective industrial silicone material which mimics the elastic and color characteristics of the conventional silicones can be recommended for preclinical exercises.

Keywords: Facial prosthesis, laboratory silicone, maxillo facial, prosthesis


How to cite this article:
Anand V, Haribabu, Vimala, Gnanasamband V. A laboratory silicone for preclinical training in ear prosthesis . J Pharm Bioall Sci 2013;5, Suppl S2:201-3

How to cite this URL:
Anand V, Haribabu, Vimala, Gnanasamband V. A laboratory silicone for preclinical training in ear prosthesis . J Pharm Bioall Sci [serial online] 2013 [cited 2020 Dec 3];5, Suppl S2:201-3. Available from: https://www.jpbsonline.org/text.asp?2013/5/6/201/114310

Maxillo facial training is an integral part of postgraduate curriculum in prosthodontics. With the increase in oral malignancy, facial tumors and trauma to face the post-surgical rehabilitation of the facial defects remains the responsibility of the prosthodontists. For the purpose of prosthetic rehabilitation, biologically accepted materials such as poly methyl methacrylate, poly vinyl chloride, poly urethane and silicone are used. [1],[2] Silicones are generally the preferred material by the patient because of its light weight, flexibility and lifelike appearance.

A structured preclinical training in the fabrication of facial prosthesis is imperative for post-graduate students to acquire clinical dexterity in fabrication of facial prosthesis. Since the cost of the current silicones is prohibitive, the laboratory phase of fabricating facial prosthesis is very limited and minimal. This material offers sufficient scope to the postgraduate student to train himself in the modulation and staining of various facial prosthesis such as auricular, nasal and orbital prosthesis. This material is akin to the silicone, which is later used for patient work.

Material description

  • Curing type - Acetoxy
  • Color - Tranlucent
  • Density - Approximately 1.04 g/cc
  • Skin formation time - Approximately 5 min at 30°C
  • Curing time - Approximately 24 h. for 2 mm thickness at 30°C
  • Movement accommodation - Approximately 15%
  • Tensile strength - Approximately 0.61 N/mm 2
  • Elasticity - Approximately 260%


Fabrication of Ear Prosthesis

Step 1: Ear impression is made using irreversible hydrocolloid alginate and custom made wax rim. wet gauze pieces are layered on top of alginate for the interlocking of the plaster to be poured [Figure 1].
Figure 1: Making of ear impression

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Step 2: Undercut areas in the impression are identified and blocked out with wax. Die stone is poured [Figure 2].
Figure 2: Block out impression partly with wax and cast poured

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Step 3: working model is retrieved from the impression carefully and base trimmed [Figure 3].
Figure 3: Working model with dental stone prepared

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Step 4: Custom tray using soft tray sheets prepared. A complete ear cast is made by making alginate impression for a person related to the patient [Figure 4].
Figure 4: Custom tray using soft tray sheets prepared for complete ear cast

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Step 5: Skin tone of the patient is matched to the oil colors. It is mixed and added to the silicone material [Figure 5].
Figure 5: Colors mixed with silicone

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Step 6: Silicone material is dispensed to the under cuts of the custom tray and filled completely [Figure 6].
Figure 6: Material dispensed with syringe into soft sheet custom tray

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Step 7: Separating medium is applied on working cast and under cuts are filled with silicone material. It is pressed against the soft sheet custom tray carrying the silicone material [Figure 7].
Figure 7: Silicone filled tray pressed against working cast

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Step 8: Prosthesis is tried on the model and trimmed before insertion on patient [Figure 8].
Figure 8: Prosthesis tried on the model

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   Discussion Top


Over a period of time various materials such as wood, leather, polyurethane and polyvinyl chloride have been used to produce esthetic properties to prosthesis, but silicone has proved to be the material of choice because of its lifelike effects and flexibility. [3] Methyl methacrylate resin is been used as a maxillo-facial material, but its use is limited due to its rigidity. The flexibility and staining of silicone are the requirements of a maxilla-facial prosthesis materials. [4],[5],[6] This industrial silicone has the property of elasticity and has the potential to incorporate stains and colors to mimic natural skin. [7],[8] Its toxicity has been tested and for laboratory purpose it is an acceptable material.


   Conclusion Top


The advantage of this industrial silicone material is the low cost factor, soft nature, flexibility, easy to fabricate and having good esthetic property and it will be an ideal material for the post-graduate student to train himself and acquire skills during his pre-clinical training program, which includes maxilla facial prosthodontics. Since the cost is not prohibitive and as this material is quite similar to the current silicones, it can be recommended.

 
   References Top

1.Wolfaardt JF, Coss P. An impression and cast construction technique for implant-retained auricular prostheses. J Prosthet Dent 1996;75:45-9.  Back to cited text no. 1
[PUBMED]    
2.Cheng AC, Morrison D, Cho RS, Archibald D. Vacuum-formed matrix as a guide for the fabrication of craniofacial implant tissue bar-retained auricular prostheses. J Prosthet Dent 1998;79:711-4.  Back to cited text no. 2
[PUBMED]    
3.Godoy AJ, Lemon JC, Nakamura SH, King GE. A shade guide for acrylic resin facial prostheses. J Prosthet Dent 1992;68:120-2.  Back to cited text no. 3
[PUBMED]    
4.Wang RR, Andres CJ. Hemifacial microsomia and treatment options for auricular replacement: A review of the literature. J Prosthet Dent 1999;82:197-204.  Back to cited text no. 4
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5.Lemon JC, Chambers MS. Locking retentive attachment for an implant-retained auricular prosthesis. J Prosthet Dent 2002;87:336-8.  Back to cited text no. 5
[PUBMED]    
6.Schaaf NG, Kielich M. Implant-retained facial prostheses. In: McKinstry RE, editor. Fundamentals of Facial Prosthetics. Arlington: ABI Professional Publications; 1995. p. 169-79.  Back to cited text no. 6
    
7.Tjellström A. Osseointegrated implants for replacement of absent or defective ears. Clin Plast Surg 1990;17:355-66.  Back to cited text no. 7
    
8.Wright RF, Wazen JJ, Asher ES, Evans JH. Multidisciplinary treatment for an implant retained auricular prosthesis rehabilitation. N Y State Dent J 1999;65:26-31.  Back to cited text no. 8
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]



 

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