Methods of alloplastic forehead augmentation using soft expanded polytetrafluoroethylene (ePTFE) and silicone implants are described. Soft ePTFE forehead implantation has the advantage of being technically simpler, with better fixation. The disadvantages are a limited degree of forehead augmentation and higher chance of infection. Properly fabricated soft silicone implants provide potential for larger degree of forehead silhouette augmentation with less risk of infection. The corrugated edge and central perforations of the implant minimize mobility and capsule contraction.
Very little has been reported regarding forehead augmentation with alloplastic implants. The literature has a large number of reports on autogenous grafting and repair in cranioplasties. The use of bioabsorbable devices, metallic devices, and acrylic devices has been reported. The author has reported forehead augmentation with silicone implants.
Various methods have been described in augmentation of the forehead and temporal region. Most of these have been temporary measures. These methods have ranged from injection of various fillers and fat. Permanent alloplastic materials that are popular for forehead augmentation vary from expanded polytetrafluoroethylene (ePTFE) implants, to acrylic implants and silicone implants.
The author favors the use of ePTFE soft sheets or soft silicone as implant materials for forehead augmentation. The advantages of soft ePTFE sheets are the simplicity of the operation and lack of capsule formation. The disadvantages of ePTFE implants are the limited amount of augmentation achievable and the slightly higher chance of infection. Even though the disadvantages of silicone implants are the higher chance of capsule formation and possibility of mobility of the implant, the advantage of an overall better result, greater degree of augmentation, and less risk of infection would put silicone implants as the choice for patients who desire a large degree of forehead silhouette enhancement. The properly prepared forehead silicone implant with corrugated edges and central perforations will allow for a more smooth contour and fixation of the implant, with minimal capsule contraction. The proper preparation of the implant is therefore of critical importance to the success of the operation. The following is the author’s personal technique.
Preoperative consultation
During the preoperative consultation, a computer imaging scan of the side profile of the forehead is important to understand the contour and degree of the patient’s desirable forehead augmentation. The surgeon then decides if the simpler ePTFE augmentation is sufficient to achieve the desirable result. If silicone implant augmentation is chosen, the proper fabrication of the implant is of critical importance as there will not be much leeway for error. The template will then be put on to the patient’s forehead after a digital photo is taken, and compared with the computerized imaging photo with the patient’s critique and consent, before it is sent for manufacture of the actual silicone implant. The following is a step-by-step outline of the author’s technique in silicone implant forehead augmentation.
Template fabrication and silicone implant creation
Fabrication of a template is a multistep process, and can be undertaken using simple materials found in a dental office (dental alginate, dental plaster, and dental wax). In overview, a negative template is created using fast-setting dental alginate, which is then used to create a positive template plaster mold of the patient’s forehead. A wax template is then sculpted onto the plaster template that will be used to create the silicone implant.
- 1.
First, the area of the patient’s forehead that requires augmentation is outlined with a surgical marking pen, and the measurements of the horizontal and vertical dimensions are recorded ( Figs. 1 and 2 ).
Fig. 1
Horizontal measurement for dimensions of forehead implant.
Fig. 2
Vertical measurement for dimensions of forehead implant.
- 2.
A fast-setting dental alginate is combined with water in a mixing bowl to form the negative template of the forehead. Before the alginate completely dries, the paste is applied directly to the patient’s forehead and sculpted to encompass the entire area that requires augmentation ( Figs. 3 and 4 ).
Fig. 3
Fast-setting dental alginate.
Fig. 4
Dental alginate is mixed with water until a thick, uniform paste develops.
- 3.
A firm base plate is affixed to the backside of the alginate template as a backing material. After the alginate fully hardens in several minutes, it is gently removed from the patient’s forehead ( Fig. 5 ). The remainder of the process can be performed at a later time without the patient being present ( Fig. 6 ).
Fig. 5
Paste is applied directly to the patient’s forehead.
Fig. 6
Hardened alginate forms an impression of the forehead and outline of the proposed implant.
- 4.
A dental plaster mold is formed by pouring the plaster carefully onto the negative alginate template. A cardboard backing can be affixed to the plaster before it dries to provide a flat surface that will aid in the next step of fabricating the wax template ( Figs. 7–9 ).
Fig. 7
Plaster is poured carefully onto the negative alginate template.
Fig. 8
A dental plaster mold is formed.
Fig. 9
A cardboard backing can be affixed to the plaster before it dries to provide a flat surface that will aid in the next step of fabricating the wax template.
- 5.
Using digital imaging analysis as a guide, the surgeon can estimate approximately how large the wax template (and ultimately the silicone implant) should be. A dental base plate wax can be heated in hot water until it softens and then placed onto the set plaster mold to sculpt the precise dimensions of the template that will serve as a guide for the silicone implant. A thickness of 3 to 4 mm will typically be necessary to accomplish the task, and no greater than a 5-mm thick implant has been clinically necessary. The template should be designed with a thicker central region that tapers laterally in the temporal areas. Inferiorly, the implant should taper toward the superior aspect of the suprabrow ridge, or bony prominence, which typically begins several centimeters above the orbital rim. The base plate wax is packaged in sheets, which can be layered and sculpted when soft until the desired size and shape have been attained according to the desired specifications ( Figs. 10 and 11 ).
Fig. 10
A dental base plate wax is heated in hot water until it becomes soft. Wax is sculpted onto the plaster mold to the precise dimensions that will match the patient’s wishes for forehead augmentation.
Fig. 11
The wax template will be used to model the final silicone implant.
- 6.
With 1 or 2 wax templates created, the patient can then return for a second visit and at that time don the wax template to see if the dimensions conform to his or her aesthetic expectations. After the template has been applied to the patient’s forehead, the patient can be asked to view his or her brow obliquely using a handheld mirror, to confirm the suitability of the design. Digital imaging of the profile view with the template in place can help the patient better appreciate whether the implant will meet the patient’s aesthetic criteria. The wax template can be further refined during this session by heating it again or sculpting it more until the patient expresses satisfaction.
- 7.
The silicone implant is carved from a standard solid rectangular block (usually 15 × 8 cm of soft silicone) that matches as precisely as possible the dimensions of the carved wax template. (The surgeon may elect to have the carved wax template and plaster mold forwarded to a silicone manufacturer for fabrication and returned, to obviate the burden of carving the implant himself or herself. Nevertheless, acquired proficiency will often permit carving the implant within 30 minutes.) A no. 10 or 15 Bard-Parker blade can be used to refine the silicone block until the shape and size conform to the proposed wax template design. The very nature of carving the silicone block will lead to an imprecise and rough-hewn contour, which not only is acceptable but leads to better protection from site dislodgement after implantation. The general shape of the implant should approximate a crescent on profile view, with the thickest section in the midforehead that tapers gradually toward the temporal edges, as described for the wax template. This crescentic shape permits a smooth transition from the augmented to the nonaugmented regions. Because of the aforementioned surface irregularities that arise after carving, it is not recommended to show the patient the carved implant for fear that he or she might misinterpret the accuracy of the design. Eight to 10 holes are then created in a uniform distribution across the implant that will facilitate tissue ingrowth and add to implant stability; a 3- or 4-mm round punch biopsy instrument can expedite creation of these holes. In addition, V-shaped wedges should be removed along the entire perimeter of the implant: the triangular excisions can measure approximately 3 to 4 mm in size and be distributed roughly every centimeter across the entire perimeter. These V-shaped excisions permit the edges of the implant to conform to the rounded contour of the forehead more easily, and minimize the risk of buckling that may otherwise occur. After carving, the implant can be autoclaved in preparation for surgical implantation ( Figs. 12 and 13 ).
