un nuevo implante para reconstruccion nasal

e90 Volume 27, Number 5, 2012

Ablative surgery or trauma to the nose can result in extensive mutilation or destruction. Surgical re-construction can accommodate young and fit individ-uals, but can be complex and challenging for elderly patients or those with complex defects.1

Extraoral implants have been used for many years2 to provide anchorage for silicone nasal prostheses, as an al-ternative to surgical reconstruction.3 Conventional den-tal implants are generally used in nasal reconstruction. However, access to the prosthetic platform for prosthetic reconstruction can be difficult because of the position-ing of the implant head within the piriform aperture.

This case report describes the design and use of a specially engineered bifunctional implant with im-proved surgical and prosthetic handling characteris-tics that may be placed via an intraoral approach. The implant is able to provide anchorage at both of its ends, making it possible to simultaneously stabilize nasal and dental prostheses.

Case RepoRt

This report describes the design and use of a bifunc-tional implant to treat an edentulous patient who had undergone a complete rhinectomy. The objective was to design an implant capable of retaining a nasal pros-thesis inserted into the nasal cavity from an intraoral approach. The intention was to utilize standard surgical instruments and prosthetic components. The implant was designed in computer-aided design/computer-as-sisted manufacturing (CAD/CAM) software with a nasal extension that could fit through the prepared site. This nasal extension incorporated a standard hex connec-tion. The implant (Fig 1) was machined from a type IV titanium rod using a computer controlled lathe and multiaxis mill.

To facilitate access to the nasal prosthetic platform, the hex was orientated perpendicular to the axis of the implant, on a flattened extension of the implant. To fit this portion through the prepared site, the hex was given a narrow platform (NP) configuration, and the diameter of the body of the implant was slightly increased from that of a standard Brnemark regular platform implant to 4.3 mm.

The aim was to surface treat the portion of the im-plant that was in contact with the bone. Those portions of the implant that traveled into the nasal aperture, or were in contact with the nasal mucosa or gingivae, were left with a machined surface. The intraoral head of the implant was provided with a standard regular platform (RP) Brnemark hex configuration.

1 Specialist in Periodontics and Prosthodontics, Private practice, London, United Kingdom; Honorary clinical fellow, St Bartholomews and The Royal London Hospitals.

2 Specialist in Prosthodontics, Private practice, London, United Kingdom.

3 Professor in Oral and Maxillofacial Surgery, St Bartholomews and The Royal London Hospitals.

Correspondence to: Dr Andrew Dawood, 45 Wimpole Street, London, W1G 8SB, United Kingdom. Fax: +4420 7935 1181. Email: [email protected]

A New Implant for Nasal ReconstructionAndrew Dawood, MRD RCS, MSc, BDS1/Susan Tanner, MRD RCS, MSc, BDS2

Iain Hutchison, FFDRCSI, FRCS (Eng and Edin), FDSRCS, MBBS, BDS3/

Extraoral implants have been used for many years to anchor silicone nasal prostheses. This report describes

the design and use of a specially engineered bifunctional implant, which is placed via an intraoral approach,

to simultaneously anchor nasal and oral prostheses for an edentulous patient who has undergone a

complete rhinectomy. The bifunctional implant was designed and milled from commercially pure titanium

using computer-aided design/computer-assisted manufacturing (CAD/CAM) technology. The nasal part of

the implant was designed to fit through the prepared site and protrude into the piriform aperture. A hex

attachment was orientated perpendicular to the axis of the implant on this extension. The intraoral head

of the implant was provided with a standard Brnemark hex configuration. Implants were placed using the

guide and associated instrumentation. This case demonstrates the potential for CAD/CAM technology to

produce bespoke implantable components at low cost. In this report, the implant greatly facilitated the

surgical and prosthetic management for the simultaneous provision of nasal and oral prostheses. Int J Oral MaxIllOfac IMplants 2012;27:e90e92

Key words: bifunctional implant, nasal implant, nasal reconstruction

2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.

Renato AlvaHighlight














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The International Journal of Oral & Maxillofacial Implants e91

To compensate for the natural inclination of the premaxilla, specially engineered, 5-mm long, 17-de-gree angled NP abutments were manufactured for the connection of a gold substructure, which would retain a silicone prosthesis produced using entirely standard prosthetic and laboratory components and materials.

Surgical planning software (Nobel Guide, Nobel Biocare) was used. Because the implant was not avail-able in the implant library, a similarly sized, long cy-lindric implant was planned in a position that would extend through the nasal floor, so that the intraoral head of the implant would be conveniently positioned for prosthesis retention, and the tips of the implants would penetrate the nasal floor in close proximity to the nasal aperture. Measurements of the available bone determined that the threaded portion of each anterior implant should be 12 mm long, ensuring that the threaded portion of the implant would be entirely within the bone.

A surgical guide was ordered from within the soft-ware. The special implants were ordered. Surgery took place using a standard guided protocol for the two bifunctional implants (Fig 2) and two further tapered implants (Replace Select, Nobel Biocare).

Connection of multiunit abutments left the pros-thetic platforms ideally located for prosthetic access, both extra- and intraorally (Figs 3a and 3b). A conven-tional impression technique was used for both the oral and nasal prostheses which were fitted after a 12-week healing period (Fig 4) that allowed for tissue healing and osseointegration before loading the implants with a fixed resin prosthesis. Had the stability of the im-plants been better at time of insertion, an immediate loading protocol may have been considered.

Implant-retained reconstruction remains the most straightforward approach to nasal reconstruction, par-ticularly in elderly patients or in those in whom access to the nasal cavity for inspection of the region is important.

Access for surgery and prosthetics to implants placed from a nasal approach is relatively less straight-forward compared with an intraoral approach. Alter-natives include the placement of zygoma implants,4 where access for surgery and the course of the implant can be challenging, or placing conventional dental im-plants horizontally.5

Many patients requiring nasal reconstruction are also edentulous (eg, five of nine patients had eden-tulous maxillae in the study by Karakoca et al6) and would benefit from oral reconstruction. Partially den-tate patients might also benefit from simultaneous oral rehabilitation if anterior teeth are missing.

The bifunctional implant has also found application in cases requiring extensive surgery in both the nasal and maxillary regions, where there may be only one suitable site for an implant, enabling simultaneous oral and nasal or orbital reconstruction, where it might not otherwise be possible to restore both cavities (Fig 5).

CAD/CAM technology offers the opportunity to produce small numbers of bespoke components at a low cost. The bifunctional implant facilitated surgical and prosthetic management in this unique case.

The provision of a fixed implant-retained denture avoided the need for a removable prosthesis, which in this case may have led to a disturbance in the seating of the nasal prosthesis if a labial flange had been pro-vided. It may have also been difficult to wear following surgery. Regardless, the patient experienced the great benefit of a fixed oral rehabilitation.

Complete rhinectomy is not a particularly common procedure, but it is highly mutilating. Surgical recon-struction is difficult and not always possible in the older or infirm patient or when tissues have been ex-tensively irradiated.

The situation of the implant may possibly be com-pared with that of a conventional dental implant that has engaged the nasal or sinus floor, achieving bicorti-

Fig 1 (Above) The bifunctional implant. The nasal extension is provided with a NP hex con-nection, oriented perpendicularly to the axis of the implant. A conventional RP hex is at the head of the implant.

Fig 2 (Right) The implants have been in-stalled, and the nasal connections positioned ideally for prosthetic access. The heads of the implants are available intraorally for con-ventional prosthodontic reconstruction. Im-plant mounts have been repositioned after removal of the surgical guide.















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e92 Volume 27, Number 5, 2012

cal stabilization. In this particular elderly patient, it was felt that anchorage would be sufficient to provide sup-port for the oral prosthesis; however, a shorter implant, with bone loss at both ends, may offer less predictable anchorage.

Static mechanical loading of the nasal portion of the implant is minimal; the potential for harmful forces to be transmitted through the retaining superstructure as the nasal prosthesis is removed might be worthy of further study.

The tissue response of the nasal mucosa to titanium implants or abutments does not appear to have been adequately studied or reported. Clinical trials are need-ed to explore this new approach to simultaneous oral and nasal rehabilitation with the bifunctional implant. It is hoped and anticipated that this modified dental implant will offer a more straightforward surgery and improved prosthetic management for patients requir-ing nasal prostheses.

aCKnowleDgment

The authors thank Lars Jorneus and Fredrick Stromberg of No-bel Biocare for the provision and prompt delivery of the bifunc-tional implants for the treatment carried out for this patient.

ReFeRenCes

1. Singh G, Withey S, Butler P, Kelly M. Forehead flap method for total nasal reconstruction. Asian J Surg 2006;29:101103.

2. Lundgren S, Moy P, Beumer J III, Lewis S. Surgical considerations for endosseous implants in the craniofacial region: A 3-year report Int J Oral Maxillofac Surg 1993;22:272277.

3. Roumanas E, Freymiller E, Chang T, Aghaloo T, Beumer J III. Implant-retained prostheses for facial defects: An up to 14-year follow-up report on the survival rates of implants at UCLA. Int J Prosthodont 2002;15:325332.

4. Bowdena J, Flood T, Downie IP. Zygomaticus implants for retention of nasal prostheses after rhinectomy. Br J Oral Maxillofac Surg 2006;44:5456.

5. Dimitroulis G. Nasal implants following nasectomy. Int J Oral Maxil-lofac Surg 2007;36:447449.

6. Karakoca S, Aydin C, Yilmaz H, Bal BT. Survival rates and periimplant soft tissue evaluation of extraoral implants over a mean follow-up period of three years. J Prosthet Dent 2008;100:458464.

Fig 3a Conventional multiunit abutments are ideally presented for connection of the nasal prosthesis.

Fig 3b Intraoral abutment ready for fixation of the maxillary prosthesis.

Fig 4 (Left) The nasal and oral prostheses in place.

Fig 5 (Right) With only a few sites available for implant place-ment, the bifunctional implant (arrow) is able to provide simulta-neous anchorage for a facial and intraoral prosthesis.


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un nuevo implante para reconstruccion nasal

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