Healing after standardized clinical probing of the perlimplant soft tissue seal: a histomorphometric study in dogs.

Abstract

Clinical probing of the soft tissues around oral implants has become a frequently used parameter for clinical monitoring. However, the healing of the disruption of the soft tissue seal as a result of probing has not yet been studied. The purpose of this study was to evaluate the healing events in the periimplant mucosal tissues following standardized clinical probing. In three foxhounds the mandibular premolars were extracted and, after 3 months of healing, TPS screw-shaped implants (ITO Dental Implant System) were installed. A plaque control regimen was performed throughout the duration of the experiment. After 3 months of healing of the transmucosal implants, clinical implant stability and healthy periimplant mucosal tissues with mostly absence of bleeding on probing were obtained. Clinical probing of the mesial and distal implant sites was performed immediately before 1, 2, 3, 5 and 7 days prior to the sacrifice of the animals. A specially manufactured titanium cylinder with a mesial and distal groove was fixed to the implants to standardize the insertion geometry of a pressure-sensitive probe (0.2-0.25 N, tip diameter 0.45 mm). The distances from the alveolar crest to the coronal border of the connective tissue adaptation to the implant and the length of the epithelial attachment were measured histomorphometrically in nondecalcified ground sections. The buccal and lingual aspects of the implants were used to determine the components of the biological width in unprobed control sites. The probe caused a separation between the surface of the implant and the junctional epithelium, but not within the connective tissue adaptation. In general, the probe tip was located at the most coronal level of the supracrestal connective tissue as determined histologically. By 1 day after separation of the periimplant mucosal tissue by probing, an epithelial attachment of approximately 0.5 mm in the apico-coronal direction was observed. The length of the epithelial adaptation showed a tendency to increase over time (day 2: 1.15 mm, day 3: 1.52 mm), and was complete at day 5 (1.92 mm). At the unprobed sites the epithelial attachment showed a mean length of 1.69 mm. Inflammatory infiltrates were practically nonexistent, indicating the absence of tissue trauma or infection as a result of probing. Clinical probing around osseointegrated implants does not appear to have detrimental effects on the soft tissue seal and, hence, does not seem to jeopardize the longevity of oral implants. The 'healing of the epithelial attachment' seems to be complete 5 days after clinical probing.