Reconstruction of cranial defect with patient-specific implants: Four different cost-effective techniques

Cranial defects secondary to trauma, surgery or pathological causes, result in large cranial imperfection, which affects the appearance of the patient as well as results in sinking flap syndrome. Rehabilitation of such a defect can be done using prosthetic options like custom-made polymethyl methacrylate (PMMA) cranial prosthesis or surgical options like outer table calvarial graft segments. It is usually observed that the conventional moulage impression of the defective site is the most difficult task. The accuracy of the prosthesis is affected by conventional moulage impression, a moulage cast of the defect and techniques of fabricating wax pattern. Orthodox method is to mark the tentative outline of the defect and make a conventional moulage impression of the site. However, this is an arbitrary method which offers challenges to accurate replication of the borders of the defect. Recently, medical imaging and digital modeling in dentistry have paved the way for digital dental practice and additive manufacturing replacing most manual or subtractive procedures. The use of computerized tomography scan to obtain a 3 D digital image of cranial defect for fabricating a replica with rapid prototyping has markedly improved the accuracy at the margin of the defect/prosthesis interface, resulting in a better fit and optimal contour lending itself to the improved esthetic outcome. It is a more reliable method of fabricating a cranial implant prosthesis, which requires minimum adjustment when the patient is on the OT table. These case reports compare rehabilitation of cranial defect with custom-made PMMA cranial prosthesis using the conventional methods as well as rapid prototyping technique. It is seen that the rapid prototyping method is expensive but accurate and gives a better esthetic outcome.