Innovative Technique for Fabrication of Forefinger Prosthesis.

Traumatic finger digit amputation may affect patient's psychology also along with a serious injury to the affected hand. Recently, advanced micro-surgical re-implantation can help save a damaged human finger that is badly injured and/or amputated. Considering its associated financial burden, a vast majority of such patients cannot afford it. For such patients, a hand/finger prosthesis may act as a blessing, boosting social performance. In the present case report, an innovative type of prosthesis finger replacement method is discussed. Copyright:

INTRODUCTION

A human forehand finger performs both function and maintains form. Forehand finger can be affected and/or damaged by various congenital abnormalities or due to disease. The human forefinger loss mostly happens due to trauma.[1] In an effort to restore the natural appearance of forefinger, a prosthodontist plays a crucial role.

These finger prostheses eliminate the psychological trauma being caused by constant remembrance of the handicap situation and hence offer psychological therapy in its true sense.

Good fitting forefinger prosthesis can enhance its functionality by restoring ideal length, maintaining sensitivity via a thin silicone sheet of lamina, protecting remaining sensitive stump, and also transmitting the required pressure and position sense for different activities. If we look at the dictionary explanation of function, we will be quite amazed as it is interesting.

As if the patient is using any kind of prosthesis for cosmetic requirements, then it is serving a function of being living a social, professional, and normal life.[2]

In the current report, an innovative method of prosthetic rehabilitation of lost multiple forefingers is being discussed and presented.

The objectives of the present technique are as follows:

To fabricate a light weight forefinger prosthesis using silicone as a material of choice, and to aid in retention[3]

To color match both dorsal and ventral surfaces separately, to maintain prosthetic form and color, and to make it match with the surrounding tissues.

CASE REPORT

A 61-year-old female patient was referred from the Department of Oral Medicine to the Department of Prosthodontics, Rural Dental College, Loni, and State Maharashtra, India, with a chief complaint of inability to chew in the last 1 year. During intraoral examination, it was revealed that she had lost all her teeth due to looseness. During extraoral examination, it was also noticed that she had a multiple loss of fingers in both her hands. She had a history of road traffic accident around two decades ago, but never presented for any kind of related treatment.

On being asked for not discussing her missing fore fingers, she replied that no one told it can be replaced and she got used to living with it over the years.

The patient was motivated for finger prosthesis along with a pair of new dentures.

An informed consent was made from the patient before starting the treatment to ensure her willingness and co-operation during the full course of therapy.

Technique

Finger impression: Various case reports were analyzed under literature review data, and it revealed that many methods are being used over the years to make forefinger impression.

In the present case report, irreversible hydrocolloid was used for primary impression. The patient's dorsal and ventral forefingers' view is shown in Figures 1 and 2.

Figure 1

Pretreatment photograph of the patient and forefingers

Figure 2

(a) Ventral view of forefingers. (b) Dorsal view of forefingers

The patient's forehand was lubricated with a thin layer of petrolatum jelly. A plastic box was selected with proper dimensions, to accommodate all the forefingers to make the impression.[4]

The patient was instructed to relax her arm and held it loose with fingers slightly separated.

Access of the hand was verified. A thin mix of alginate (Neocolloid, Dpi Supplies, Zhermack Neocolloid Alginate, Jaipur, Rajasthan, India) was painted over the impression surface of the forefingers, especially in between areas. The remaining impression material was poured into the box. After final setting time was reached, the tear strength of alginate impression material is less, hence the forefingers were removed from alginate impression, by gently flexing the hand taking care avoiding tearing of alginate impression. [Figure 3].

Figure 3

Preliminary forefinger impression

A working stump model was made, pouring the forefinger impression in a dental stone (Kalastone, Kalabhai Dental Pvt. Ltd, Mumbai, Maharashtra, India). A dental vibrator was used to minimize air voids. The forefinger hand model outline was traced on a graph paper. A donor hand was selected and placed over the graph paper, overlapping the working stump model tracing. A second tracing was then traced. The length of the forefinger wax patterns was accordingly established [Figure 4].

Figure 4

Donor (patient's relative) hand traced

Wax glove technique was utilized where a donor finger pattern was selected. The digits were marked with a marker pen till the predetermined forefinger length from the tracing pattern done previously[5] [Figure 5].

Figure 5

Digits duplicated with putty consistency silicone

A putty silicone impression of the donor fingers was made and numbered. This definitive impression was poured in wax (Modelling Wax, Dental Products Of India-Dpi, Mumbai, Maharashtra, India), allowing the wax to cool for 5 min.

After the wax reached room temperature, it was poured to ensure good reproduction of details [Figure 6].

Figure 6

Digits duplicated with putty consistency silicone

Nail bed preparation was carried out by creation of an undercut beneath the cuticular margin in the wax pattern to retain the acrylic resin nail within the finished prosthesis. An appropriately sized artificial nail was selected and positioned in the silicone prosthesis.

To enhance the realistic appearance, the nail was shaped according to the nail of the remaining natural forefingers.

A stump model was prepared and was painted with five layers of die spacer for space for definitive impression material [Figure 7].

Figure 7

Die spacer applied

The selected wax donor's forefingers were adapted to the stump model. During try-in stage, the fit, stability, and seating of the forefinger wax patterns were evaluated for acceptable shape and size [Figure 8].

Figure 8

Wax pattern for the fabricated digits

A definitive stump impression was made by relining the waxed forefingers with light viscosity silicone impression material [Figure 9].

Figure 9

Wax pattern relined with light viscosity silicone

The model was poured in Die-stone type-IV gypsum material (Kalabhai, DPI, India). Retentive loops were incorporated to aid in repositioning during packing stage.

Flasking of the forefinger wax pattern was done in Type III dental stone (Kalastone, Kalabhai Dental Pvt Ltd, Mumbai, Maharashtra, India). When set, the wax was boiled-out and the mold was carefully opened. Melted petrolatum jelly was applied in all the three pours for loading it with room temperature vulcanizing (RTV) silicone [Figures 10 and 11].

Figure 10

Dewaxing for right hand forefingers

Figure 11

Matched silicone packing done

Advantages of the three pour technique are as follows:

A high viscosity silicone does not flow into inaccessible areas, which may result in voids in the processed prosthesis

The three-pour technique facilitates in color matching by improving the realistic appearance of artificial silicone forefinger prosthesis. The ventral surface of natural forefingers is lighter in shade so this technique helps in packing a comparatively lighter shade of silicone material on ventral surface of mould and darker shade of silicone material on dorsal surface of mould and processed.

Color matching was done with intrinsic color stains according to patient's skin. It increases service life of the prosthesis along with a translucent realistic appearance.

A custom-made flask was fabricated using strong magnets to create tight seal and at the same time closed with light pressure to remove excess material. The processing was done at room temperature [Figure 12].

Figure 12

Silicone fingers positioned on master cast

Finishing and polishing was done following gentle retrieval of the forefinger prosthesis with overnight curing. A silicone polishing kit was used [Figure 13].

Figure 13

Postoperative view with Indian Namaskar, a gesture of thank you

Maintenance phase for the forefinger silicone prosthesis includes some recommendations as follows:

Considering the fragile nature of silicone material similar to skin, the patient must stay away from using sharp tools such as knives to avoid damage to the silicone prosthesis

Avoid exposure of the silicone prosthesis to extreme temperature such as direct sunlight

RTV silicone has inherent elastic nature, but it must not be over elongated

Silicone prosthesis can be cleaned using mild anti-bacterial soap and soft bristle brush

Avoid night time wear of silicone prosthesis as it can distort or damage and also, the tissue bed needs to breathe

Last but not the least, avoid smoking as it may lead to yellowish discoloration tinge of the silicone forefinger prosthesis

Periodic re-evaluation of the patient is critical for early findings to initiate appropriate steps in a timely manner.

DISCUSSION

It was reported by Pillet in 1981[1] that trauma is the most common reason behind finger amputations.

In some cases where the remaining amputated portion of finger is restored, it may be rejoined by microsurgery as reported by Wilson et al. in 1983.[6] In the present case report, silicone material was used for fabrication phase due to its excellent real life-like esthetic value in accordance with Buckner in 1980[7] and Kanter in 1970.[8] It is also reported by Burkhardt in 1990[9] that silicone layer hydrates ocular skin layer, providing comfort to the patient.

Future considerations

In the event of digit loss, even the simplest of daily tasks turn into a challenge. Doppen et al. in 2009[10] used extraoral implants to retain finger prosthesis. An active prosthesis (bionic) enables the user in grasping and maneuvering objects as these are custom-build on residual stump and possess sensor driven motors and a power source. These are state of the art electronics.

CONCLUSION

With the fabrication of a multiple finger passive prosthesis, the patient's psychology was directly addressed. When she came to our department, she was just concerned for her set of dentures. As her finger rehabilitation was not done for two long decades, she got psychologically depressed and initially not even prepared for any kind of finger prostheses treatment. She adjusted her life to live with this trauma. After finger rehabilitation, she wore a confident smile, thus improving her social index. Hence, finger prosthesis not only improves function, The forefinger loss replacement with artificial silicone prosthesis not only improves function, but also aids in gaining social acceptance in outside environment and workplace along with family acceptance and support.

Ethical clearance

Approved by the Institutional Research Cell.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.