| The purpose of this study was to compare two approaches for the management of experimental peri-implantitis induced by cotton ligatures placed around porous-surfaced dental implants. Thirty implants were placed in 5 beagle dogs, 3 fixtures on each side of mandible, 4 months after extraction of the mandibular premolars and first molars. After re-entry and abutment connection, a cotton ligature was placed around the neck of each implant and forced apically to disrupt the soft tissue seal of the peri-implant space. Oral hygiene was withdrawn and administration of a soft diet allowed gross plaque accumulation. Periodic radiographic and microbiologic exams were performed. After 6--8 weeks the ligatures were removed and regular hygiene re-instituted. Four weeks later and after commencement of systemic antibiotics, the "rescue" surgical procedures were performed. These were based on GBR principles and done using a split-mouth model design. On one side of the jaw DynagraftRTM Putty was used as a graft while on the other side, the same graft material was used along with Capset(TM) as a barrier.; Results from microbiologic, radiographic, clinical and microscopic assessments revealed that: (i) Porphyromonas gingivalis was detected at all peri-implantitis sites as the disease progressed and at the time of rescue surgery, up to 3 mm of the porous surface was no longer submerged in bone because of the bone loss that occurred; (ii) Assessment of prepared sections using BSEM and statistical treatment of the data indicated that both treatment approaches i.e., Dynagraft + Capset and Dynagraft only, were effective in terms of inducing new bone formation and allowing for re-osseointegration to varying degrees; (iii) Dynagraft + Capset treatment group had significantly better values for the regained bone height and bone ingrowth fraction for defect segment, parameters that reflect the level of re-osseointegration induced by the treatment. |
