Guided bone regeneration with the combined use of resorbable membranes and autogenous drilling dust or xenografts for the treatment of dehiscence-type defects around implants: an experimental study in dogs.

PURPOSE: This study aimed to measure the numbers of viable bone cells present in autogenous drilling dust (ADD) and mandibular particulated bone (MPB) and to histomorphometrically compare the effects of the combined use of resorbable membranes and ADD or xenografts for the treatment of dehiscence-type defects around implants.

MATERIALS AND

METHODS

The left mandibular premolars were extracted from 4 adult beagle dogs. After a 3-month healing period, 4 standardized bone defects were prepared on each mandible, and 1 implant was placed per defect. The 4 sites in each dog were allocated to 4 different treatment groups: 1 site received ADD alone (ADD); 1 site received a Cytoplast membrane supported by ADD (ADD+CP); 1 site received BioCera alone (BC); and the final site received a Cytoplast membrane supported by BioCera (BC+CP). Each animal received a series of 3 bone labels. Three months following these regenerative surgeries, animals were sacrificed and histomorphometric examinations were carried out. In addition, in 3 of the 4 dogs at the time of regenerative surgery, ADD was obtained using implant drills (group 1), MPB was obtained using a fissure bur and rongeur (group 2), and 1.0 cm3 of each was then cultured. Cultured cell counts and osteocalcin synthesis analysis using reverse transcription-polymerase chain reaction were performed on cells from these 2 groups at 4 and 9 weeks after regenerative surgery. Alkaline phosphatase activity (ALP) was measured at 9 weeks in both groups.

RESULTS

MPB revealed greater cell counts than ADD after 4 and 9 weeks. Cells stained positively for ALP and osteocalcin in both groups. Fluorescence microscopy showed 22.4% bone formation with ADD+CP, 17.8% with BC+CP, 13.1% with ADD, and 6.4% with BC at 8 weeks. Bone regeneration heights were 2.0 mm with AD, 1.9 mm with ADD+CP, 1.7 mm with BC+CP, and 1.3 mm with BC. Bone regeneration areas measured 1.0 mm2 with ADD, 0.9 mm2 with ADD+CP, 0.6 mm2 with BC+CP, and 0.3 mm2 with BC. Bone-to-implant contacts were 53.1% with ADD, 46.6% with ADD+CP, 44.1% with BC, and 33.7% with BC+CP.

CONCLUSIONS

ADD appears to be a useful material for closing dehiscence-type defects, and the use of a membrane was not found to affect bone formation during the treatment of dehiscence-type defects around implants in this study. However, larger studies are needed before fully endorsing its widespread use.