Understanding peri-implantitis in skin paddle penetrating implants

Background

Implant supported dental restorations in free fibular reconstructed jaw bones completes the rehabilitation of oral cancer patients. However, the incidence rate of peri-implantitis is higher in grafted bones covered with skin paddle as compared to bone cover with mucosa. The biology of peri-implantitis in grafted bones is not fully understood. This paper is aimed towards histo-pathological changes occurring in peri-implant dermal and epidermal connective tissues and resultant periimplantitis.

Aim/Hypothesis

Hypothesis – Progressive inflammatory changes occur in dermis and epidermis in peri-implant connective tissues result in granulomatous periimplantitis.

Material and Methods

Implant supported dentures is the treatment of choice for free fibular grafted patients post-ablative surgery. The study population considered for the present study was those patients who have received implants in free fibular grafted bone surrounded by skin paddle in two years (between January 2016 to December 2017). These patients are on regular 6 monthly follow-up. Clinical peri-implantitis lesions reported in these patients between June 2016 to April 2019 were analyzed. These peri-implantitis lesions were excised under local anesthesia. The excisional biopsy tissues were sent for histopathological reporting as per department protocol. The histopathological reports of all these peri-implantitis lesions along with patients demographic characters were collected from hospital electronic medical records system. The respective slides were retrieved for study purpose and re-evaluated by a single pathologist for uniformity of reporting.

Results

During the review period of June 2016 to December 2017, 106 patients received implants in jaw bones. In 41 patients implants were placed in free fibular grafted bone lined with skin paddle. Out of which 11 (26.8%) patients developed peri-implantitis till April 2019. M+F = 8-3, Radiated- Non-radiated = 7-4, 2 patients developed peri-implantitis twice hence total reports available for analysis were 13. These patients reported to hospital 176 to 754 days (364 + -194 days) from the day of respective implant placement. Radiated patients reported early periimplantitis (287 + -99 days) as compared to non-radiated patients (498 + -260 days). All the biopsy reports suggested inflammatory granulomatous changes in the subepithelial connective tissue. In 8 cases hyperplastic proliferation was evident, 4 slides showed parakeratotic changes, 2 slides hyperkeratosis was seen. Only one report suggested severe dysplasia of superficial squamous epithelium, however, there was no invasion in deeper sections.

Conclusion and Clinical Implications

Incidence of peri-implantitis in implants surrounded by skin paddle has higher as compared to those surrounded by oral mucosa. The histological features suggest acute to chronic granulomatous inflammatory changes in sub-epithelium. Squamous epithelium undergoes changes ranging from hyperplasia to dysplasia with hyperkeratosis or parakeratosis. These lesions may be superimposed by bacterial invasion. Immediate excision of these periimplantitis lesions is important for long term success of implant