Background. Peri-implant keratinized mucosa contributes to long-term health and success of implant-supported restorations. It is more easily maintained and less vulnerable to inflammation than non-keratinized alveolar mucosa. Understanding changes that occur in peri-implant mucosa may influence treatment planning, post-operative procedures and maintenance. Digital photography and computer imaging may enable us to gain a more precise assessment of peri-implant tissue than past methodologies.
Purpose. Monitor changes in peri-implant tissues using ImageJ computer analysis. To identify if changes vary by mesial, mid, distal and surface area of peri-implant keratinized mucosa. In addition, the relationship between tissue thickness, proximity to adjacent dentition, mucosal health and mucosal marginal stability will be investigated.
Methods. Seventeen systemically healthy, non-smokers, receiving one-stage Straumann implants with an adjacent control tooth were enrolled. Digital photographs were taken at baseline, 3 and 6 months after implant placement and analyzed with ImageJ software. Plaque and gingival indices, pocket probing depths, bleeding on probing and tissue thickness were examined at 3 and 6 months. Inter-rater agreement was evaluated by intraclass coefficient.
Results. Twenty-one implants were placed in the mandibular posterior, five 4.8mm regular neck (RN) and sixteen 6.5mm wide neck (WN). Loss of mean width peri-implant keratinized mucosa was significantly greater on the lingual surface than buccal, .7 vs. .1mm respectively (p<.001*). Loss was positively associated with 6.5mm WN implants (p<.001*). Lingual mucosa was significantly more likely thin (p<.02*) and thin tissue decreased twice that of thick (0.4mm vs. 0.2mm, p>.05). Inter-rater agreement intraclass coefficient was .99.
Conclusion. Imaging analysis software, ImageJ, yields a more precise assessment and quantification of peri-implant soft tissues than current chair-side techniques and may facilitate a database for future studies. Lingual peri-implant tissue and wide-neck implants were significantly correlated to a loss of keratinized mucosa. This may be due to tension or “stretching” of mucosa, causing it to thin, making it more susceptible to recession as a manifestation of inflammation. Thinning of mucosa may be a consequence of clinicians positioning and inclination of the implant within the alveolar housing, which is influenced by anatomical limitations, bone resorption patterns and biomechanic requirements.