Choosing an implant for the lower jaw
Last reviewed: 19.10.2021
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Choosing an implant involves choosing the material from which it was made, as well as choosing the shape necessary to improve the appearance of the patient. Ideal material for implantation in the lower jaw and cheekbone should have the necessary consistency, flexibility and density; it must be areactive, resistant to infection, stable, available for removal and replacement, easy to manufacture and safe for surrounding tissues. The only alloplastic material that meets practically all these requirements is a monolithic silicone elastomer rubber (Silastic).
Silastic is made of a polymer, the consistency of which can be changed to choose softness and flexibility. The organism perceives this material, forming around it a fibrous capsule, without deforming the implant itself. Implants with holes are additionally stabilized by ingrowth of connective tissue. From the material, it is possible to manufacture implants of various sizes and shapes industrially, using computer simulations. They can be customized by changing the shape in the operating room, cutting off with conventional tools and blades.
Choosing one of the many available implants for the lower jaw of Silastic can be difficult. The first solution to be adopted is the preference for an elongated mandibular implant to the central chin implant. The three most studied and commonly used extended mandibular implants are an elongated anatomical mandibular implant (four sizes), a variety of Muscular chin implants (standard, vertical, oblique anterior or posterior) and Mittelman anterior-dental implants (four sizes). All three types of implants have different configurations and approaches to use, but give very good results. The elongated anatomical mandibular implant gives a different chin increase, depending on the patient's need, but the size of the implant part under the chin hole is approximately the same, regardless of the amount of enlargement in the chin itself. In other words, the increase in the area of the anterior mandibular groove remains the same, regardless of the size of the chin enlargement. The mandibular implant Flowers is characterized by various inclinations in the central, chin and conical continuation along the lower jaw under the chin opening.
Mittelman's front-jaw implants give four options for increasing the chin, in combination with four comparable options for bringing these implants to the area of the anterior mandibular groove. They are designed for varying degrees of correction of the anterior mandibular groove simultaneously with an increase in the chin. In addition, there is an elongated mandibular implant that does not increase the chin proper, but corrects the anterior mandibular groove. It becomes an extremely important addition to facelift in patients with an adequate chin, which is so often combined with the presence of the anterior mandibular groove. There is a modification of an elongated chin implant, proposed by Terino. It has a more square chin protrusion, whereby a more prominent chin can be created.
Silastic implants described herein may have different densities. The softer monolithic implants are more flexible, and they are easier to install through smaller incisions. They are more consistent with the lower jaw and less promote bone resorption. To increase the lower jaw, we use Silastic implants with an index of 10 on a durometer. Most elongated mandibular implants and all premaxillary implants have multiple apertures that help fix the implants to the periosteum or soft chin tissues. The surgeon can also make holes with a biopsy instrument. For implant sizes, there is no standard (for example, the average sizes for different manufacturers are not the same). However, there is a certain sequence among the implants of different configurations, manufactured by one manufacturer. The choice of a physician is facilitated by the availability of "calibrators" supplied by implant manufacturers. Calibrators can be inserted into the created pocket until the surgeon is satisfied with the result. The calibrator is then removed and an implant of the same size is inserted.
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