28/07/2014
AO Technical Commission Approved

Facial Shape System

Facial implants, including malar and chin implants, are used to add or restore contour irregularities and/or proportion to the face, for aesthetic (enhancement) or reconstructive (correction of deficiencies) purposes. Traditionally, these implants were made of silicone with resulting overlying soft tissue deformities due to capsule formation around the implant. Hence, there was a need for another material, such as porous polyethylene, to address this clinical issue and improve surgical outcomes.

The new Facial Shape System (Fig 1a and 1b) consists of flexible implants designed for augmenting the contours of the craniofacial skeleton. These implants are made of high density polyethylene, an inert, nonresorbable and biocompatible material. The implants are preshaped to restore several facial anatomical areas, minimizing the need for intraoperative contouring. When necessary, the implants can easily be trimmed with a scalpel or high speed burr. A variety of implant sizes and shapes support different clinical needs. The semi flexible nature of the material allows the implant to conform to underlying bone during fixation, and its porous structure supports fibrovascular ingrowth for host incorporation rather than encapsulation.

The refined implant surface facilitates insertion. Registration tabs assist positioning in terms of verifying symmetry. Furthermore, by submerging them for several minutes in hot sterile saline (over 70 degrees C) manual contour is possible to obtain the desired form, which will be maintained after cooling. Since Facial Shape must be placed directly on the recipient bone, adequate subperiosteal exposure is important to allow visualization of anatomical landmarks and proper placement. Implants are provided sterile and are for single-patient use (nonresterilizable). It is important to prevent contamination through surgical clothing or powder from surgical gloves, and when using intraoral incisions, proper aseptic techniques are highly recommended.

In order to achieve successful implantation, careful preoperative planning should reflect the patient's desires, evaluate the skeletal dimensions, and analyze both the skeleton and the soft tissue envelope. Sizers made from silicone (Fig 2) were developed exclusively to help select the most appropriate implant. The sterilizable and reusable cutting board (Fig 3) with measuring references aids when carving, measuring, and photographing the implants. A positioning instrument (Fig 3) helps to introduce the implant and immobilize it during fixation. Titanium screws from the matrix midface set can be used for this purpose in the appropriate length: self-drilling in 6 mm and 8 mm, self-tapping in 10, 12 and 14 mm, and emergency self-tapping in 6, 8, 10, 12 and 14 mm as required. Screw fixation eliminates any gaps between the inner surface of the implant and the surface of the facial skeleton.

Porous polyethylene implants should not be used, either for load-bearing applications or as a structural support to bone, in cases where active or latent infection is present, in inadequate coverage of healthy vascularized tissue, or in systemic disorders with limited blood supply implications.


Anatomical Shapes

The implants are available in two anatomical shapes:

  • Chin implants
  • Malar implants (see CMF/Midface/Plates).

Chin implants

Chin implants (Fig 1a, above) are used to increase the anterior projection of the chin. They may be used to treat isolated small chins (microgenia) or together with mandible angle implants to camouflage small lower jaws (micrognathia).

The adequacy of chin projection should take into account several variables including the patient's sex, the effect of occlusion on lower lip position, the thickness of the chin pad, and the depth of the labiomental fold. When these variables are not considered, implant augmentation may result in a chin that is unnatural and too large, particularly in women. Chin augmentation with certain shaped implants can create unnatural chin contour. Implants that augment only the chin point produce an abrupt, protruding chin rather than a jaw-chin continuum. Extended one piece implants do not always match the contour of the native mandible. Particularly when placed through small intraoral incisions, minimal inaccuracies in placement or asymmetries in the mid-aspect (chin point) of the native mandible may result in gross distortions and irregularities in the more lateral aspect of the chin.

A flexible titanium connector (Fig 1a) in between both polymer segments introduces a three-part assembly for better anatomical fit, allowing the implant to merge imperceptibly with the native deficient mandible. This solves some of the issues previously mentioned. Depending on patient's needs, there are two shapes for the chin: round and square, with different size options. Registration tabs have been developed as part of these implants to assist positioning.

Hazards and labeling

Due to varying countries’ legal and regulatory approval requirements, consult the appropriate local product labeling for approved intended use of the products described on this website. All devices on this website are approved by the AO Technical Commission. For logistical reasons, these devices may not be available in all countries worldwide at the date of publication. 


Legal restrictions

This work was produced by AO Foundation, Switzerland. All rights reserved by AO Foundation. This publication, including all parts thereof, is legally protected by copyright.

Any use, exploitation or commercialization outside the narrow limits set forth by copyright legislation and the restrictions on use laid out below, without the publisher‘s consent, is illegal and liable to prosecution. This applies in particular to photostat reproduction, copying, scanning or duplication of any kind, translation, preparation of microfilms, electronic data processing, and storage such as making this publication available on Intranet or Internet.

Some of the products, names, instruments, treatments, logos, designs, etc referred to in this publication are also protected by patents, trademarks or by other intellectual property protection laws (eg, “AO” and the AO logo are subject to trademark applications/registrations) even though specific reference to this fact is not always made in the text. Therefore, the appearance of a name, instrument, etc without designation as proprietary is not to be construed as a representation by the publisher that it is in the public domain.

Restrictions on use: The rightful owner of an authorized copy of this work may use it for educational and research purposes only. Single images or illustrations may be copied for research or educational purposes only. The images or illustrations may not be altered in any way and need to carry the following statement of origin “Copyright by AO Foundation, Switzerland”.

Check www.aofoundation.org/disclaimer for more information.

 

If you have any comments or questions on the articles or the new devices, please do not hesitate to contact us


"approved by AO Technical Commission" and "approved by AO Foundation"

The brands and labels "approved by AO Technical Commission" and "approved by AO Foundation", particularly "AO" and the AO logo, are AO Foundation's intellectual property and subject to trademark applications and registrations, respectively. The use of these brands and labels is regulated by licensing agreements between AO Foundation and the producers of innovation products obliged to use such labels to declare the products as AO Technical Commission or AO Foundation approved solutions. Any unauthorized or inadequate use of these trademarks may be subject to legal action.

2020 IM covers

AO TC Innovations Magazine

Find all previous issues of the AO TC Innovations Magazine for download here.

Meet the Experts

Directly learn about AO Approved Solutions from the Experts themselves.

Innovation Awards

Innovation awards

Recognizing and fostering excellence in surgical innovation.

X
Cookies help us improve your website experience.
By using our website, you agree to our use of cookies.
Confirm