Journal of Dental Implants

CASE REPORT
Year
: 2017  |  Volume : 7  |  Issue : 2  |  Page : 64--69

Prosthetic challenges in a free fibula flap mandibular reconstruction: A 10-year follow-up of a case


Tatiana Vargas-Koudriavtsev, Rodrigo A Jimenez 
 School of Dentistry, University of Costa Rica, , Central America, Republic of Costa Rica

Correspondence Address:
Dr. Tatiana Vargas-Koudriavtsev
School of Dentistry, University of Costa Rica, San José, Costa Rica, San Pedro, Montes De Oca
Republic of Costa Rica

Abstract

This case report describes the prosthetic challenges of a patient who underwent a partial hemimandibulectomy and a subsequent free fibula graft after a mucoepidermoid carcinoma resection. This type of osseous reconstruction has several functional as well as esthetic difficulties that must be considered when designing the prosthesis. A thorough case description as well as its follow-up is presented and discussed.



How to cite this article:
Vargas-Koudriavtsev T, Jimenez RA. Prosthetic challenges in a free fibula flap mandibular reconstruction: A 10-year follow-up of a case.J Dent Implant 2017;7:64-69


How to cite this URL:
Vargas-Koudriavtsev T, Jimenez RA. Prosthetic challenges in a free fibula flap mandibular reconstruction: A 10-year follow-up of a case. J Dent Implant [serial online] 2017 [cited 2021 Oct 21 ];7:64-69
Available from: https://www.jdionline.org/text.asp?2017/7/2/64/225405


Full Text

 Introduction



Fibula-free flaps, first reported by Hidalgo in 1989,[1] are an excellent option for the reconstruction of large mandibular defects after trauma, congenital conditions, or tumor removal.[2],[3] Fibula is an ideal donor site because it helps restore both the mandibular and facial contour and also provides the necessary density and stability for dental implant placement,[4],[5] it is also well vascularized which makes it highly viable for integration in the recipient site and can be modeled to the desired mandibular contour.[6]

Despite the financial challenges of fixed restorations, an implant-supported prosthesis is the ideal treatment option to avoid graft damage due to the usual lack of stabilization of a mucosupported removable prosthesis. Furthermore, soft tissues covering this type of osseous reconstructions frequently lack adequate keratinized tissue, which makes it difficult for this mucosa to comfortably bear a denture. In addition, since the fibula is usually much thinner (<14 mm) than the segment of the mandible it replaces (except in cases of a severely resorbed jaw), there is a considerable reduction in ridge height and a consequential decrease in stability of any removable prosthesis.[5]

In these cases, the prosthesis needs to consider the restoration of hard and soft tissues and its interphase with the remaining natural tissues. A partial hybrid denture is an optimal alternative for several reasons that will be discussed. There are few publications that present a long follow-up of these cases and discuss its challenges and complications. The aim of this report is to discuss different management criteria and the challenges associated to this kind of cases.

 Case Report



In 2006, a 47-year-old female attended the postdoctoral program in prosthodontics for rehabilitation after having surgery for mucoepidermoid carcinoma. The right mandibular body was completely removed [Figure 1].{Figure 1}

The maxillofacial surgeon at the Calderón-Guardia Hospital performed segmental mandibulectomy from the right third molar to the left central incisor and performed an immediate reconstruction with free flap bundle-osseocutaneous fibula. The bone segment was contoured to simulate the contour of the mandible, and microvascular anastomosis of the peroneal vessels with the facial vessels was carried on. Peroneal graft was fixed to the mandible with osteosynthesis metallic plates and screws, which were removed 6 months later [Figure 2] and [Figure 3]. The patient also received radiation therapy.{Figure 2}{Figure 3}

Nine months after the removal of the plates, an implant-supported fixed prosthesis was planned since the transitional removable prosthesis performed poorly due to the unfavorable shape of the residual ridge. Although the graft was stable and properly integrated, it was observed that the lack of keratinized tissue at the site of the future restoration would represent a complication for a removable prosthesis as well as for dental implants. Despite this limitation, the prosthetic and surgical team decided against further surgical procedures to avoid any risk of losing the free fibula graft.

As stated before, a metallic framework provisional partial denture was fabricated to improve the patient's mastication, avoid supraeruption of the antagonist teeth, and it was later duplicated to construct a surgical guide for correct implant placement [Figure 4] and [Figure 5].{Figure 4}{Figure 5}

The use of the surgical guide allowed for optimal implant placement position, and four implants (Zimmer® AdVent, Zimmer Biomet Holdings Indiana, USA) were placed on the grafted area under local anesthesia [Figure 6]. The implants had a diameter of 3.7 mm and a platform of 4.5 mm and had a length of 10 mm and 13 mm [Figure 7]. The most distal implant was long enough to achieve bicortical anchorage. All implants had primary stability at the time of placement and received healing abutments (Zimmer).{Figure 6}{Figure 7}

Five months after implant surgery, osseointegration was verified and the third implant (mesial to distal) was diagnosed as failing [Figure 8]. Since it was not one of the distal implants, the prosthetic team decided to follow the original plan of fabricating a partial fixed-detachable prosthesis. A definitive pick-up impression was made with polyether (Polyether Impregum™ Penta™ 3M ESPE, Madrid, Spain) and a custom tray.{Figure 8}

The final cast was analyzed for available space using a stone index with the acrylic teeth (Ivoclar Vivadent, ON, Canada) that were later used for the definitive prosthesis [Figure 9]. The framework was cast in a type 4 reduced gold alloy, with a high water design to ensure the proper space for hygiene (Argenco WR+, Argen, San Diego, California) and was checked for fit and passivity, without further complications [Figure 10]. Teeth were fixed to the framework, the waxing procedure was completed, and the prosthesis was processed with heat-polymerized acrylic.{Figure 9}{Figure 10}

The prosthesis was inserted [Figure 11] and torqued to 30 Ncm 3, and access holes were sealed with resin composite (P60, 3M ESPE). The patient was satisfied with the esthetic as well as the functional aspects [Figure 12].{Figure 11}{Figure 12}

Oral hygiene instructions included the use of a water irrigator on the site of the implants and brushing and flossing the remaining teeth. The patient came for examinations once a year for a follow-up period of 10 years, during which the implants, surrounding tissues, and prosthesis were evaluated. Only on the 6th year of follow-up, the patient presented mucosal irritation around the most anterior implant [Figure 13], which was easily resolved with periodontal therapy without further complications. A computed tomography scan was performed on the 10th year, which showed good integration of all the implants [Figure 14].{Figure 13}{Figure 14}

 Discussion



Fibula-free flap is a feasible option for reconstruction of large osseous defects in the mandible. Chiapasco et al.[5] report a survival rate of fibula flaps of 95%, being the only limitation the fact that these flaps have a limited thickness, which presents functional and esthetic complications from a prosthetic point of view. Since these flaps are positioned to follow the lower border of the mandible to maintain a harmonious face contour, the space between the upper surface of the flap and the occlusal plane is too wide, which means that the space for a prosthesis is very large.

The thickness of the fibula graft might be enhanced by means of distraction osteogenesis, and additional reconstructive treatments with autogenous grafting material.[7],[8],[9] However, due to the morbidity and the limited willingness of the patients to withstand additional surgeries, the prosthetic team must be ready to work in challenging conditions from a functional and esthetic point of view.[5]

On the other hand, the type of mucosa over this graft is often poorly keratinized and therefore not an optimal site for a removable base. The grafted soft tissues are not fixed to the periosteum; therefore, they are mobile and usually the reconstruction of the vestibule is not possible.[10] Furthermore, these patients tend to present xerostomia due to radiation therapy and resection of salivary glands. All the later reasons make it difficult to wear a removable denture, and therefore, a rehabilitation with dental implants is the best prosthetic choice.

Since there is no mandibular canal in the fibular graft, the entire width of the bone tissue can be used to place longer implants and even bicortical anchorage might be achieved.[3] Some authors report that implant placement might be performed simultaneously in one stage with the free fibula graft reconstruction.[11],[12] However, in the present case, the surgical as well as the prosthetic team decided to first wait for the fibula integration to allow the correct development of the vascularization. Furthermore, there is bone remodeling in the 1st month after the surgery, and it is advisable to wait to achieve a more precise implant placement.[13]

On this patient, several prosthetic design criteria were implemented. Since the position of the ridge is very low because of the decreased thickness of the fibula graft, a removable partial denture would have a large torsion moment and would make it quite unstable. Due to the fact that this patient was lacking a considerable amount of both hard and soft tissue, a partial hybrid denture was selected. This type of prosthesis allowed us to replace not only teeth but also soft tissues. On the other hand, a regular metal-ceramic fixed implant-supported bridge would have esthetic disadvantages since the prosthetic crowns would have been very long. Furthermore, since a mild motor limitation of the lip following surgery was detected, access to hygiene was compromised. For this reason, a high water design was suggested. This provided easier access to cleaning with water irrigators and interdental brushes. The prosthesis needed to be very rigid to prevent flexion of the bar, fracture of the veneering acrylic resin, and teeth.

The interphase between the prosthesis and the remaining tissue also needs to be addressed carefully. We based our approach on the available literature regarding pontic tissue contact on fixed partial prostheses, but we adapted it since the interphase is not horizontal but vertical or oblique.[14],[15],[16],[17] This fact provides some particular characteristics, both anatomical as well as functional. There are usually morphological differences in width and shape of the ridge in horizontal and vertical segments. Furthermore, compression of the tissue during the seating of the implant restoration does not occur in the same way. Instead of pure compression and blanching when the prosthesis is torqued down, the sliding movement on an inclined plane will cause tissue erosion and injury if the interphase is too tight. There is also a high potential for food impaction in the area because of this vertical or oblique joint. For this reason, we constructed the prosthesis/tissue contact in acrylic resin instead of metal, so it could be easily adjusted and polished. Studies show no significant cytotoxicity effects of adequately heat cured polymethyl methacrylate resin to oral mucosa.[18] Our approach was to achieve an relatively tight and long interdental contact between the remaining most distal natural tooth (in this case, left mandibular lateral incisor) and the adjacent prosthetic tooth. Under this contact, we expected to accomplish a light contact between the ridge mucosa and the pink acrylic of the prosthesis but a contact nonetheless. We did this through several adjustments with disclosing materials such as Fit-Checker (GC America R) and Pressure Indicating Paste (PIP, Mizzy R).

Regarding the follow-up appointments and findings, the patient showed mucosal inflammation around the most anterior implant on the 6th year. This was probably due to the lack of keratinized tissue around the implants. This agrees with other publications that state that the overall incidence of peri-implant mucositis ranges from 16.3% to 24%.[19] However, the mucositis was treated by a periodontist without further complications, the prosthesis was carefully cleaned, and a reinforcement of hygiene protocols was given.

After the rehabilitation, the patient returned to an unrestricted diet, had normal speech, and judged her aesthetic outcome as excellent, which is coincident with what Cordeiro et al. reported as usual for patients with hemimandibular defects.[4] In this case, there was close communication between the surgical and the prosthetic teams, and therefore, the reconstruction of the defect allowed for good placement of the osseointegrated implants with the subsequent prosthesis. In general, the reconstructive team must have a realistic grasp of the situation, placing the patient's well-being as the top priority of the treatment.

 Conclusion



This case report describes the prosthetic rehabilitation challenges and design criteria that must be taken into account for a patient who received a fibula-free flap after a partial mandibulectomy due to an aggressive carcinoma. Despite the functional and esthetic compromises due to the anatomy of the grafted site, the patient's perspective and quality of life must be integrated into the treatment plan. A fixed-detachable implant-supported partial prosthesis might be the best solution since it replaces the teeth and also the soft tissues, and it prevents the prosthesis from damaging the underlying bone and mucosa. Special attention should be provided to the prosthesis' relationship with the tissues, vertically and horizontally.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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