|Year : 2014 | Volume
| Issue : 4 | Page : 168-171
Fabrication of localizing template for extraoral implant in a patient with congenital defect in one ear
Susan Mir Mohammad Rezaei1, Fatemeh Nematollahi2
1 Department of Prosthodontics, Faculty of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
2 Department of Prosthodontics, School of Dentistry, Tehran Islamic Azad University, Tehran, Iran
|Date of Web Publication||12-Sep-2014|
Assistant Professor, Department of Prosthodontics, School of Dentistry, Tehran Islamic Azad University, Tehran
Source of Support: None, Conflict of Interest: None
Introduction: The use of osseointegrated extraoral implants for retention of extraoral prostheses, such as ears offers ideal support and retention, and improves patient's appearance and quality of life. However, the best result may be obtained only by careful planning number, position and orientation of the implants and this article presents a method of making of a surgical stent that is simple, economic and stable during all phases of surgery. Case Report: A 26-year-old male (without any remarkable systemic disorder) presented with congenital defect in one ear. An impression was made of congenital defect in left ear, wax pattern of defect and missing ear is made, the wax prosthesis is changed into a clear acrylic resin, and on the other hand an occlusal maxillary splint is also fabricated with clear acrylic resin. The occlusal splint and the acrylic resin ear are joined together using an extraoral bar that is made of proper length of wax and also is checked on patient's face and processed into a clear acrylic resin. Discussion: By this kind of surgical guide, we can determine the best location of the implants and location of the implants will not compromise to fabricate ear prostheses with ideal form and location. This surgical guide can be used for the pretreatment of radiographic stent.
Keywords: Craniofacial abnormalities, maxillofacial prosthesis, prostheses and implants
|How to cite this article:|
Rezaei SM, Nematollahi F. Fabrication of localizing template for extraoral implant in a patient with congenital defect in one ear. Dent Hypotheses 2014;5:168-71
| Introduction|| |
Auricular defect occurs secondary to congenital malformations, trauma, or surgical removal of neoplasms. 
The use of osseointegrated extraoral implants for retention of extraoral prostheses, such as ears offers ideal support and retention, and improves patient's appearance and quality of life. This prosthesis will be useful to the patient in having an artificial auricular without using adhesive and with good orientation without replacing. 
However, the best result may be obtained only by careful planning number, position and orientation of the implants and proper connection of the auricular prosthesis to implant retaining structure. The location and orientation of extraoral implants is important to obtain an optimal prosthetic result. Pre-implant treatment planning is critical to coordinate the patient's surgical and prosthetic management because treatment planning should involve all members of the treatment rehabilitation team. 
Also, pre-implant treatment planning is important to orient ideal positioning of implants and the ideal location and orientation of implants is critical for optimal prosthetic results.  Many techniques have been presented for orientation of the surgical template. ,,
Ciocca L et al. described CAD-CAM construction of an auricular template for implant insertion.  In this method, a mirrored volume of the healthy ear was rapidly prototyped for a clinical trial in an appropriate position relative to the patient's face. Three ideal positions for the implant were chosen in the inner volume of the mirrored ear. The same positions were transferred to a diagnostic template that was rapidly prototyped with a positioning arm extending to the zygomatic arch fabrication of a 3-dimensional surgical template to guide the placement of implants to retain an auricular prosthesis presented by Asher et al. This procedure requires a diagnostic wax pattern that is checked while on the patient to ensure it is positioned correctly and is also the correct size. The wax pattern is processed into a clear, methyl methacrylate resin, 3-dimensional surgical template and used as surgical stent. 
Charkawi et al. was drawing the ear on a transparent celluloid paper and flipping it to the opposite side and relating it to the fixed anatomical features on the face of the patient.  The template was first reported in 1997 by Reisberg and Habakuk,  who described a positioned location at the time of surgery will guide in locating the implants to obtain optimum results (locations of implants will not compromise to fabricate ear prostheses with ideal form and location).
Russell  made an accurate duplicate of wax ear to the acrylic surgical template that has indexes (external auditory canal, posterio-superior and inferior borders of the remaining tragus (if present). Many practitioners have used imaging techniques; for example: CT, digital volume topography, laser scanning and imaging technique that used to fabricate stereo lithographic models and customized drill guides. 
The aim of the present case report was to provide a method of making of a surgical stent, which is simple, economic and stable during all phases of surgery.
| Case Report|| |
A healthy young 26-year-old male patient (without any systemic disorder e.g. diabetic and cardiovascular diseases etc) involving congenital defect in one ear and with normal skeletal and tooth relation, was referred to the Department of Implants at Faculty of Dentistry, Tehran University of Medical Sciences, Tehran, Iran and we wanted to fabricate a surgical stent in order to place implants in ideal locations. To consider publication ethics, informed consent was obtained from the patient to publish his images. Before the impression was made, we placed orientation marks such as the location of the external auditory meatus, outline of highest and lowest limits of the ear in defected ear and location of the external auditory meatus and the angulations of the long axis of the defected ear by considering undefected ear and anatomic landmarks in the face [Figure 1].
Facial hair was protected by a light application of petroleum jelly. A rim of boxing wax built around the area. An irreversible hydro colloid (Alginate; zhermack, SpA, Badia, Italy) impression material was used with the addition of 50% more water to improve its flow and a disposable syringe was used in depositing impression material in to the area, and with a backing of quick-setting plaster a suitable support for impression was provided. This backing plaster was made of several layers of orthopedic plaster ribbons (gypsum bond) that was inserted one after another, on the impression [Figure 2]. We made impression from defected and healthy ears, and impressions was poured in dental stone type IV (Die kean, Heraeus kulzer, Armonk NY). Later an irreversible hydrocolloid impression of maxillary arch was made and poured in the dental stone. By considering the healthy ear, a wax sculpting of prosthetic ear was fabricated with base plate wax to the final contours acceptable to the patient [Figure 3]. The wax pattern was flasked and processed in clear acrylic resin (Orthodontic acrylic; Great Lakes orthodontic, Tonawanda, NY), and we drilled holes in to the acrylic resin ear to indicate the ideal implant insertion.
A maxillary acrylic resin splint was fabricated using maxillary cast and was provided sufficient retention by engaging undercuts on the maxillary teeth and with acrylic resin projection at the maxillary central and lateral incisor area. An external acrylic resin bar to follow the contour of the face from the lips to the desired location of the reconstructed ear with base plate wax was made and then processed in clear acrylic resin [Figure 4].
|Figure 4: External acrylic resin bar, maxillary acrylic resin splint and acrylic resin ear|
Click here to view
The maxillary occlusal splint intraorally have evaluated and placed the acrylic resin ear at the proper position with the help of an eyeglass and by drawing two lines in upper and lower areas of defected ear. An assistant maintained it in position and we used autopolymerizing acrylic resin (pattern Resin; GC America, Chicago) to connect the maxillary occlusal splint, external acrylic resin bar, and acrylic resin ear, to assemble the guide [Figure 5].
We used this stable stent to aid in inserting of implants in surgery stage in an ideal location [Figure 6].
This splint can also be used as radiographic stent with Gutta-percha in holes.
| Discussion|| |
The design of the surgical craniofacial implant stent should be proper for positioning of the implant, accurateness, safe, inexpensive and time saving and it must be effective and not interface with soft tissue. The technique which is proposed in this study includes the intact ear is related to fix anatomical feature of cranial (upper jaw). This method provides a simple and easy way to duplicate and transfer the exact size of ear and can be easily disinfected and used in operating room. This technique is safe because it does not need exposing the patient to radiation according to the imaging systems. 
Some of imaging techniques are very difficult to apply in the operating room.  CAD-CAM construction of an auricular stent for craniofacial implant positioning is an expensive method. When patient has a congenital facial asymmetry, this splint allows three-dimensional visualization for patients and doctor especially when it is made of skin-colored wax. This technique is also very useful for cases of bilateral missing ears. Using this technique, the patients are scheduled for only 2 appointments. The limitation of this method is the need of precision and dexterity in attaching three parts of surgical splint, and we are not able to use this procedure for edentulous patients.
| Conclusion|| |
This method is a safe, economic and time-saving technique to locate ideal position of implants in auricular prosthesis. This technique could be used in all patients with aplasia, trauma and resection of one ear
| Acknowledgment|| |
We would like to acknowledge all intellectual supports from Department of Implant Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]