Dinesh Rokaya

Stress Distribution in Implant Retained Finger Prosthesis: A Finite Element Study

BACKGROUND Finger amputation may result from congenital cause, trauma, infection and tumours. The finger amputation may be rehabilitated with dental implant-retained finger prosthesis. The success of implant-retained finger prosthesis is determined by the implant loading. The type of the force is a determining factor in implant loading. OBJECTIVE To evaluate stress distributions in finger bone when the loading force is applied along the long axis of the implant using finite element analysis. METHOD The finite element models were created. The finger bone model containing cortical bone and cancellous bone was constructed by using radiograph. Astra Tech Osseo Speed bone level implant of 4.5 mm diameter and 14 mm length was selected. The force was applied to the top of the abutment along the long axis of the implant. RESULTS Finite element analysis indicated that the maximum stress was located at the head of abutment screw. The minimum stress was located in the apical third of the implant fixture. The weakest point was calculated by safety factor which is located in the spongy bone at apical third of the fixtures. Finally, 4.9 times yield stress of spongy bone was needed for the deformation of the spongy bone. CONCLUSION Finite element study showed that when the force was applied along the long axis of the implant, the maximum stress was located around the neck of the implant and the cortex bone received more stress than cancellous bone. So, to achieve long term success, the designers of implant systems must confront biomaterial and biomechanical problems including in vivo forces on implants, load transmission to the interface and interfacial tissue response.

One- vs two stage surgery technique for implant placement in finger prosthesis.

BACKGROUND The loss of the finger can lead to psychological problems. Although several reconstructive techniques may exist, the use of osseous-integrated implants to anchor digital prosthesis presents a suitable alternative for the amputation of finger. The surgery for implant placement has initially been described as a two-stage technique. However, no study in the literature has attempted to compare this technique with one-stage technique and stated a clear superiority technique in the implant retained finger prosthesis. METHODS This article describes two cases of digital amputation as a result of accident; a 45-year-old female whose second finger of right hand was lost and a 25-year-old male patient with amputation of the first finger of right hand. RESULT AND CONCLUSION One-stage implant placement technique for implant retained finger prosthesis is a reliable, safe and efficient option that allows a good result in a significantly lower operating time and hospital visits compared to the two-stage technique. It could therefore, be considered as good option for implant retained finger prosthesis.

Rapid fabrication of a digital prosthesis.

Finger prosthesis often needs refabrication due to its discoloration following use. This article presents a novel, economical, and cost-effective technique to duplicate the patient׳s existing prosthesis to obtain a new wax replica, which is then clinically tried and processed to obtain new silicone finger prosthesis. This technique requires comparatively less clinical and laboratory steps as to fabricate an entirely new prosthesis. The newly fabricated silicone finger prosthesis has the fit and marginal adaptation of the patient׳s existing prosthesis but the esthetics is improved.

Prosthetic rehabilitation of an ocular defect with post-enucleation socket syndrome: A case report

Ocular trauma can be caused by road traffic accidents, falls, assaults, or work-related accidents. Enucleation is often indicated after ocular injury or for the treatment of intraocular tumors, severe ocular infections, and painful blind eyes. Rehabilitation of an enucleated socket without an intraocular implant or with an inappropriately sized implant can result in superior sulcus deepening, enophthalmos, ptosis, ectropion, and lower lid laxity, which are collectively known as post-enucleation socket syndrome. This clinical report describes the rehabilitation of post-enucleation socket syndrome with a modified ocular prosthesis. Modifications to the ocular prosthesis were performed to correct the ptosis, superior sulcus deepening, and enophthalmos. The rehabilitation procedure produced satisfactory results.

Assistance of Pressure Conformer for Reconstruction of Lower Fornix

Absence of fornix in anopthalmic socket can result in difficulty in prosthetic and cosmetic rehabilitation. A 30-year-old female was presented with absence of the lower fornix in anopthalmic socket. A stock conformer was used to create continuous downward pressure with the help of an acrylic rod, gauze and a medical adhesive tape. Eventually, a lower fornix was created and finally rehabilitated with ocular prosthesis.