Optical Coherence Technology Detects Early Signs of Peri-implant Mucositis in the Minipig Model

Background: Peri-implant mucositis defines the inflammation of gingival tissue surrounding osseous integrated implants without destruction of supporting bone. Untreated mucositis may develop into peri-implantitis with irreversible resorption of alveolar bone and implant failure. Mucositis is reversible with early intervention; however, existing clinical approaches have proved inadequate to reveal initial stages of this complication. Optical Coherence Tomography (OCT) is a non-invasive modality that provides real time, cross-sectional optical images of tissue up to 2-3mm in depth from the surface. Here, the minipig model assessed the diagnostic capability of OCT to detect early signs of mucositis by imaging microstructural changes of soft peri-implant tissue based on its correspondent histological analysis. Methods: Implants were placed in edentulous ridges of anesthetized animals. After a 7-8 weeks healing to achieve osseous integration, peri-implant disease was induced by ligature procedures. At endpoints of 3, 7 and 12 days after ligation, implant sites were clinically examined by bleeding on probing, probing depth, clinical attachment loss, suppuration and radiographic changes in bone level. Biopsies were collected for ex vivo optical imaging and histological analysis. Results: As early as 3 to 7 days after ligation, imaging documented the internal disarrangement of peri-implant gingival tissue and the images correlated well with corresponding histological specimens. Clinical signs of inflammation and loss of alveolar bone were absent. Conclusion: Development of clinical applications of OCT imaging for early diagnosis of mucositis could lead to therapeutic interventions to reduce one of the causes of implant failure.