Background and objectives: Bone regeneration and aesthetic outcomes may be compromised when immediate implants are placed at extraction sites with dehiscence defects. The PCL–TCP scaffold is a recent innovation in bone regeneration. The hypothesis for this study was that the insertion of a PCL–TCP scaffold into tooth extraction sockets with a facial wall defect and simultaneous immediate dental implant placement would result in favorable bone regeneration and implant stability. The study compared in a monkey model (1) peri-implant bone regeneration, (2) bone-to-implant contact and (3) implant stability, following immediate implant placement into tooth sockets with facial wall defects in the following groups: (a) PCL–TCP scaffold used as space filler (test); (b) particulate autogenous bone used as a graft (control).

Methods: The upper left central and lateral incisors were extracted in 18 Macaca fascicularis . The facial bone plate was surgically removed and a dental implant was inserted. In 8 control monkeys, the bony defect was reconstructed with autogenous particulate bone while in 10 test monkeys a PCL–TCP scaffold was used. The monkeys were sacrificed after 6 months and the specimens were analyzed by histology and histomorphometry.

Results: Implant survival was 100%. Better maintenance of facial bone contour was noted in the test group, however bone regeneration was noted only at areas adjacent to a bony wall of the defect. The mean bone-to-implant contact was 27.6 ± 19.1% (control) and 6.8 ± 7.9% (test). The mean bone area percentage was 11.8 ± 10.1% (control) and 6.8 ± 6.9% (test).

Conclusions: Although the use of a PCL–TCP scaffold showed better maintenance of the alveolar contour as compared to autogenous particulate bone at 6 months, only minimal amount of bone regeneration and bone-to-implant contact were noted.

Key words: PCL–TCP; bone regeneration; immediate implants