CONVENTIONAL APPROACH FOR FABRICATION OF ORBITAL PROSTHESIS : A CASE REPORT Affiliation

1. Lecturer, Department of Prosthodontics, Kathmandu University School of Medical Sciences, Dhulikhel Hospital. 2. Professor, Department of Prosthodontics and Maxillofacial Prosthetics, People's Dental College and Hospital, Tribhuvan University. 3. Lecturer, Department of Prosthodontics and Maxillofacial Prosthetics, Gandaki Medical College Teaching Hospital and Research Center Pvt Ltd, Tribhuvan University.


INTRODUCTION
Disfigurement of the face due to exentera on of an eye is a very trauma c event in a person's life not only physically but also psychologically and emo onally as face and eyes are the iden es of the person.Exentera on is the surgical removal of orbital content that is eye, adnexa, and the part of the bony orbit.¹Orbital rehabilita on is a complex procedure which requires individuality in fabrica on according to the pa ent.The earliest known examples of restora ons dated back to the fourth dynasty in Egypt where rehabilita on of eye by using precious stones, copper, gold, enameled bronze, earthenware have been found in the shrunken socket of the cadaver during tomb excava on.²For the prosthesis to be successful various factors should be taken into considera on like color, contour, texture, biocompa bility, durability, ease of use, weight, and availability.Although several materials are available, not a 3,4 single maxillofacial material fulfill all of these proper es.Prosthesis for orbital defects is made from a variety of materials, such as vinyl chloride polymer, acrylic resin, 5 medical grade silicone or polyurethane.Reten on also plays a key role in the success of the maxillofacial prosthesis (i.e., anatomic, adhesives, and mechanical).Adhesives may cause skin allergies in long term use in some pa ents and for high degree of reten on significant amount of suppor ve 6 ingredients may be necessary to add into the adhesives.
Though expensive, some mes, magnets have been incorporated into the dentures for be er reten on of the 7 prosthesis.On long term use the property of magne sm may be lost or magnets may corrode.Hence the most accepted mode for improving reten on is through use of 8 osseointegrated implants.But due to many reasons like inadequate bone, added surgery, extra cost for the implant and past radia on history to that area, this kind of treatment 9 is contraindicated.Reten on of orbital prosthesis through the use of eyeglass frames is one of the most acceptable method as it assure precise and consistent posi oning of the prosthesis since the minute mistake in posi oning the 10 prosthesis will be dis nctly no ced.Moreover, eyeglass frames offer an addi onal high degree of bonding, mainly to the acrylic prostheses.
This case report describes a comprehensive technique for the fabrica on of spectacle retained heat ac vated polymethylmethacrylate (Trevalon Heat Cure, Dentsply India Pvt Ltd) orbital prosthesis.

CLINICAL REPORT
A 26 year old, male pa ent reported to the Department of Prosthodon cs and Maxillofacial Prosthe cs, People's Dental College and Hospital, Kathmandu, with a chief complain of unaesthe c appearance of face due to loss of an eye and associated structure.His past history reveals exentera on of orbit five years back because of squamous cell carcinoma of the orbit.On clinical examina on, the defect was large (4 X 5) cm healed with the fibro c ssue without any possible undercut for reten on.Presence of healing burn injury around le alar region contraindicated complete facial impression.An acrylic orbital prosthesis a ached to eyeglasses frame was planned for complete prosthe c rehabilita on of the pa ent.

Recording the Impression
An informed consent was obtained from pa ent himself and explained about the procedure.Pa ent was relaxed and made to rest comfortably for impression making.Petrolatum was applied on eyebrows so that impression material would not s ck on it and removal of impression material would be easy without any discomfort to the pa ent.The modeling wax (Pyrex Polykem, India) was adapted around the defect with adhesive to receive the impression material.Prepara ons were made to mix alginate (ZelganPlusTM, Dentsply India Pvt Ltd, Gurgaon, India) in two consistencies, first syringe consistency was mixed and poured gradually and gently un l it covered the en re defect which was dispensed using a syringe and secondly tray consistency was mixed and placed over syringe consistency.Then the stapler pins were placed over the alginate to hold the dental plaster which acts as a matrix for the impression.The impression material along with dental plaster was allowed to set.The set impression was gently taken out in single piece without tearing the impression material.

Wax pa ern Fabrica on
The master cast was poured in type IV gypsum (Pearlstone Diestone type IV, Asian Chemicals, Gujarat India) for finer surface details and more strength.Modeling wax (Pyrex Polykem, India) was adapted over the cast and tried in pa ent's face.Size and orienta on of the ocular part of the prosthesis was determined by taking various measurements on pa ent's contralateral side.Measurements from nasal bridge to the inner canthus, inner canthus to center of iris and center of iris to outer canthus of the contralateral eye were made while pa ent was looking and fixing the eye at a distant gaze.The measurements were recorded and transferred on to the master cast.Sclera pa ern was also fabricated with the help of modeling wax and acrylized in a conven onal manner.Sclera was tried in pa ent and iris orienta on was done by asking the pa ent to look and fix the contralateral eye at distant gaze and by measuring the contralateral iris.Iris pain ng was done to match the contralateral side, comple ng the fabrica on of the ocular por on of orbital prosthesis.

Fabrica on of heat cure orbital prosthesis
The orbital part of prosthesis was fabricated on modelling wax with the help of custom made ocular prosthesis.Following dewaxing and acryliza on, final processing of the prosthesis was done.Pain ng of acrylic prosthesis was done to match the color to that of right side.The final prosthesis was verified for the orienta on of pupil, propor on, size, shape and color of sclera as compared to the contralateral eye.The wax prosthesis along with custom made ocular prosthesis was tried on pa ent.To determine final posi on of ocular prosthesis it was first secured onto a bed of modelling wax and posi oned according to measurements from contralateral eye.The anteroposterior posi on of the prosthesis was confirmed from profile as well as from coronal view.Eyelids and remaining por on of the prosthesis was carved and tried for final posi on and fit into the defect.The wax pa ern with master cast was flasked and dewaxed with the wax sculpted prosthesis.Transparent heat cure acrylic resin was mixed in a porcelain jar, according to the instruc on given by manufacturer.Acrylic color was mixed into the base color of acrylic resin uniformly to match intrinsic stains and skin shade of pa ent.The colored heat cure acrylic resin was packed, bench cured, cured and bench cooled for overnight.A er bench cooling, the prosthesis was retrieved, finished and polished.Natural hair from pa ent was glued over the eyebrow area to make eyebrows  and readymade eyelashes (Huda beauty eye lashes, distributed by Huda beauty LLC, Dubai) were glued on the eyelids of the acrylic prosthesis, to give lively appearance.
The eyeglass frame was tried in the pa ent.Once pa ent approved eyeglass frame, the prosthesis was a ached on the eyeglass frame for reten on and proper orienta on.Margin of the prosthesis was aligned along the border of the frame for natural appearance.The prosthesis was placed on the pa ent and home care instruc ons were given.Regular follow-up was conducted for the evalua on of the prosthesis.The pa ent was happy and sa sfied as the prosthesis fulfilled the func on and esthe c demand which made him socially presentable.

DISCUSSION
Orbital defect rehabilita on is a tedious procedure involving aesthe c element.Even a minute difference in posi oning the eye and the color of the prosthesis will be markedly no ceable on the appearance of the pa ent.The intensive surgical procedure, a major financial burden to the pa ent may lead pa ent to seek economical prosthe c treatment op ons.When the reconstruc ve surgical procedure is beyond the capacity of the pa ent, orbital prosthesis is the best alterna ve as it is simple, economical and does not 11 involve any invasive procedure.Facial rehabilita on by the prosthesis with defect due to surgery leads to less postsurgical trauma to the pa ent as it boost the personality, self-image and social acceptability thus enhances the quality of life of the pa ent.Desirable proper es of material for maxillofacial prosthesis comprises of elas city, biocompa bility, moldability, longevity and ability to accept 12 intrinsic and extrinsic colorants.Anatomic reten ve undercuts and eyeglass frames are the most frequently 4 used tradi onal method to retain orbital prostheses.The availability of anatomic undercut play the major role in the selec on of material used for fabrica on of the orbital prosthesis.Flexible material will be beneficial for the pa ents presen ng with engageable orbital undercuts.In contrary, in cases with complete loss of orbit and without any possible engageable undercuts, the eyeglass frame reten on method is the economical and convenient as eyeglass frames are easier to place in an exact, reproducible prosthesis posi on.The pa ent was treated with eyeglass frame retained acrylic resin orbital prosthesis in this case report.Acrylic prostheses a ached to the eyeglass frames are much superior compared to the older methods of silicone adhesive systems, as it is more biocompa ble and 13 can be easily removed and placed in the same posi on.Acrylic resin is a durable material compared to the silicone Case Report orbital prostheses which have a rela vely short lifespan (on 14 an average of 1.5 to 2 years).

CONCLUSION
The u liza on of custom fabricated orbital prosthesis has proved to be blessing for the pa ent who cannot undergo extensive reconstruc on surgery or afford the expensive treatment op ons.The acrylic orbital prosthesis presented hereis cost effec ve, affordable and acceptable which meet the physiologic, anatomic, func onal and cosme c requirements of the pa ent.In addi on, the prosthesis design incorporated reten on features during the func on, which is the major criteria for the success of the prosthesis.This method has provided favorable results in terms of pa ent cosme cs, recogni on, and expecta ons.

FINANCIAL DISCLOSURE
None

Figure 1 :
Figure 1: Making impression of defect