Dr.Radhika Jain1, Dr. Sandeep Gurav2, Dr.Gurkaran Preet Singh.3
2Professor and Head,
Dental and Prosthetic Surgery, Tata Memorial Hospital, Mumbai, India.
Soft-tissue management around dental implants placed in microvascular free-flaps is considered an enigma due to the thick, mobile nature of skin pedicel. In spite of the debulking procedures, these tissues are not an ideal substitute to attached mucosa. Undoubtedly, peri-implant soft- tissue management is considered as a critical factor in long-term maintenance of dental implant health. This case report describes the various challenges faced during the prosthetic rehabilitation of dental implants placed in a marginal mandibulectomy defect reconstructed with free-radial artery forearm flap (FRAFF). The exuberant soft tissue proliferation of the soft tissue flap entailed a need to modifythe prosthetic procedures and design.
Keywords: free flap, implants, peri implant soft tissue
Citations:JainR, Gurav S, Sinh GP. Peri-implant soft tissue management of a free-radial artery forearmflap by modified prosthetic design. J Prosthodont Dent Mater 2022;3(2):6 1 – 6 6
Fascio-cutaneous or osteo-cutaneousfree-flapsserve as an indispensable tool in there construction of mandibular and mid-facial defects following complex surgical resections.1Free-radial artery forearm flap (FRAFF) is a workhorse in replacement of moderate to large soft-tissuedefects.2The flap has several advantages- its pliability, thin anatomy, predictable blood supply and ease of harvest.3 As a fascio-cutaneous flap, it consists of skin, subcutaneous tissue and deepfascia with its thickness ranging from 0.5-2.0 cm.4The thickness depends mainly on the location of harvesting flap and built of the patient.5 From a dental rehabilitation perspective, however, it does not provide an ideal soft tissue substitute for attached mucosa when associated with dental implants.6 The “multiple mattress-like” layers of the skin pedicle predispose the implants to develop several peri-implant complications such as peri-implant mucositis and peri-implantitis.7The movable thick tissues need to undergo further corrective procedures such as debulking, de-epithelization and sulcus creation procedures in order to create an ambient soft-tissue bed. Thus, peri-implant soft tissue management is of utmost importance in long-term dental implant success.8 This case report describes challenges faced during prosthetic rehabilitation due to the unfavorable growth of the FRAFF soft tissues. In spite of repeated debulking procedures, the tissues continued to show exuberant growth. Eventually, the prosthetic design of the implant-supported over denture had to be modified to accommodate for the proliferative tissues and ensure optimal peri-implant soft tissue health.
A 55-year-old reported with an exophytic gingival growth around a bulky, over-contoured, faulty fixed prosthesis in anterior mandible. Upon biopsy, the lesion was diagnosed as well-differentiated squamous cell carcinoma. The patient underwent a peroral Central Segment Marginal Mandibulectomy with left elective neck dissection (levels I-IV) under general anesthesia. The remaining mandibular height was 26 mm which allowed primary placement of four dental implants (Straumann SP, SLactive, 4.1 X 8mm) in the inter foraminal region of the native mandible, each achieving an acceptable torque of 30-35 N cm. Post- implant surgery, a free-radial artery forearm flap (FRAFF) was placed in order to achieve a soft -tissue coverage. (Figure 1)
After 3 months of uneventful healing and satisfactory osseointegration, prosthetic rehabilitation was planned as he did not receive any form of adjuvant therapy. Owing to the broader epithelial thickness of the skin-lined flaps in contrast to the oral mucosa, procedure of de-epithelization and debulking of the flap (termed as stage 2 surgery) was carried out in collaboration with the plastic and reconstructive surgery team. During the same step, cover screws were removed exposing the implants and four axial overdenture attachments (Novaloc Abutments RN, Straumann) each of 6 mm height, were placed. An immediate acrylic stent was placed within 24 hours, after the patient recovered from the general anesthesia. During weekly follow-ups, the peri-implant tissue healing was observed and the stent was modified accordingly. However, the soft tissues continued to proliferate to a Grade 3 hyperplastic mucosa (in accordance with Kumar et al classification) in spite of the debulking procedure 7 (Figure 2).
Within the first month of second stage procedure, the 6 mm locators were completely submerged under the hyperplastic mucosa and the stent could no longer be placed. The debulking procedure was again attempted for the second and third time but the results were the same. As the proliferative growth was exceeding 6mm height of the Novaloc abutments (which was the maximum available height), a custom- made bar supported overdenture prosthesis was planned. The first step in the prosthesis fabrication was recording an open-tray impression. The height of the stock impression copings (6mm) was insufficient to emerge out of the soft tissues and engage in the bulk of the impression material. Hence, they were modified by carefully building a wall of pattern resin (Pattern Resin LS, GC) and auto-polymerising resin (Trevalon; Dentsply Sirona) around their superior rim (Figure 3 and 4).
After obtaining a proper impression, a customized Cobalt-chromium bar (Preci-line, Ceka) was milled whereby the overall platform of the bar was raised by 5-6 mm above the soft-tissue bed. This was to ensure access for the oral hygiene tools such as q-tip to rub topical steroids and other medicaments in case of any peri-implant inflammation (Figure 5 and 6). The fit of the bar was verified radiographically and torque tightened to 25Ncm.
Conventional steps for heat-cure based implant- supported overdenture processing was followed (Figure 7).
On the day of delivery, the soft tissues were again debulked and the denture was immediately placed. The prosthesis was to be placed continuously for a month and the patient was asked to report for regular follow-up. The patient was counselled about the importance of oral hygiene maintenance and steps to ensure the same. Soft tissue proliferation settled in the next few weeks, though there were instances of mild inflammation around distal implants (due to lack of optimal oral hygiene). At 6 months follow- up, the patient was satisfied and reported satisfactory masticatory function with a grade 1 hyperplastic mucosa.
Dental implant placement and prosthetic rehabilitation are essential in the improvement of the overall quality of life in head and neck cancer patients. An essential facet of the dental implant survival is the maintenance of the soft tissue peri-implant health.
The present case report is a modification of the ‘Sub-periosteal dissection and denture-guided epithelial regeneration (SD-DGER)’ whereby the interim denture helps to guide the regenerated epithelium of the skin pedicle of the free-flaps in formation of stable soft tissue bed.9 Unlike the original technique, following debulking, the lingual and buccal flaps were not sutured transcutaneously and the mode of retention of the overdenture was also modified.
As opposed to pedicle lining on fibular bone graft, FRAFF soft tissue graft has less fat content and is more fibrous and muscular. The debulking is, thus, challenging and may not be as effective as in case of free-fibular osteocutaneous flaps (FFOCF). Hence modifications of prosthetic design should be considered to accommodate for the soft tissue thickness. This method presents with a predictable outcome in patients where FRAFF and ALT (antero-lateral thigh flap) may be used for soft-tissue closure. Also, the current patient was non-radiated. Probably, the tissues behave differently in the radiated population and thus need to be dealt accordingly.
The additional cost of the milled bar and clips was a definite disadvantage of this technique. Also, meticulous maintenance of oral hygiene is a definite requirement to ensure the success of this method and thus patient motivation is an essential pre-requisite.
The soft tissue proliferation/ hypertrophy of pedicle skin graft is a common problem. Due to thickness of tissues and non-adherent nature, maintenance of peri-implant health becomes challenging. The present case report describes the peri-implant soft tissue management of a FRAFF by modified prosthetic design.
The authors would like to thank the Plastic and reconstructive team (PRS team) for helping in debulking and de-epithelization procedure. A special mention to Ceralife Dental Lab for milling of the Cake Bar and assisting in the laboratory procedures
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