Young-Kyun Kim, DDS, PhD, Jeong-Kui Ku, DDS, PhD, FIBCOMS. JKAOMS 2020;46:361-6. https://doi.org/10.5125/jkaoms.2020.46.5.361

We aimed to evaluate the efficacy of demineralized dentin matrix (DDM) fixed with recombinant human bone morphogenetic protein-2 (rhBMP-2) through an experimental and a clinical study. Unilateral upper second and third premolars of eight beagles were extracted. A mucoperiosteal flap was elevated around the extraction socket, and a bone defect was made using a surgical drill. Each DDM was fixed with rhBMP-2, and autogenous bone was grafted at the bone defect area with a collagenous membrane. The beagles were euthanized at two, four, eight, and 12 weeks after receiving the bone graft. Block specimens involving grafted bone and surrounding natural bone were extracted. A total of 23 patients who received bone grafts using human DDM fixed with rhBMP-2 (AutoBT BMP) with implant placements (36 implants; maxilla: 14, mandible: 22) were selected. The implant stability, marginal bone loss, and clinical outcome were evaluated. Three trephine cores were harvested fourmonths after bone grafting, and histologic examination was performed. In the histological evaluation performed four weeks after the bone graft, autogenous bone showed 52% new bone formation and DDM fixed with rhBMP-2 showed 33% new bone formation. Twelve weeks after the bone graft, autogenous bone showed 75% new bone formation and DDM fixed with rhBMP-2 showed 48% new bone formation. In the clinical study, favorable osseointegration was obtained in 35 out of 36 implant sites (one case of osseointegration failure). In all cases, severe complications were not observed. Histomorphometrically, new bone formation was observed in 14.98% of the cases. The residual DDM particles were 6.22%. AutoBT BMP provides good osteoinductive and osteoconductive potential and clinical efficacy.

Young-Kyun Kim, DDS, PhD, Jeong-Kui Ku, DDS, MMsc, FIBCOMS. JKAOMS 2020;46:211-7. https://doi.org/10.5125/jkaoms.2020.46.3.211

In 2007, recombinant human bone morphogenetic protein-2 (rhBMP-2) was approved for use in humans at a concentration of 1.5 mg/mL with absorbable collagen sponges as an alternative to autogenous bone grafts for alveolar ridge augmentation, defects associated with extraction sockets, and sinus augmentation. However, the use of supraphysiological doses and the insufficient retention of rhBMP-2, when delivered through collagen sponge, result in dose-dependent side effects related to off-label use. Demineralized dentin matrix (DDM), an osteoinducing bone substrate, has been used as an rhBMP-2 carrier since 1998. In addition, DDM has both microparticle and nanoparticle structures, which do not undergo remodeling, unlike bone. In vitro , DDM is a suitable carrier for BMP-2, with the continued release over 30 days at concentrations sufficient to stimulate osteogenic differentiation. In this review, we discuss the histological outcomes of DDM loaded with rhBMP-2 to highlight the biological functions of exogenous rhBMP-2 associated with the DDM carrier in clinical applications in implant dentistry. Impact Statement: Demineralized dentin matrix (DDM) has been used as an recombinant human bone morphogenetic protein (rhBMP-2) carrier and osteo-inducing bone substrate to facilitate continued release and stimulate osteogenic differentiation. In this review, we discuss the histological outcomes of DDM loaded with rhBMP-2 in order to highlight the biological functions of exogenous rhBMP-2 associated with the DDM carrier in clinical applications in implant dentistry.

Background: The aim of this study was to assess the accuracy of virtual planning of computer-guided surgery based on the actual outcomes of clinical dental implant placement.Methods: This retrospective study enrolled patients among whom implant treatment was planned using computer-guided surgery with cone beam computed tomography (CBCT). The patients who received implant according to the guide with the flapless and flapped approach were classified as group 1 and 2, respectively, and the others who could not be placed according to the guide were allocated to the drop-out group. The accuracy of implant placement was evaluated with the superimposition of CBCT.Results: We analyzed differences in the deviated distance of the entrance point and deviated angulation of the insertion of implant fixtures. With regard to the surgical approach, group 2 exhibited greater accuracy compared to group 1 in deviation distance (2.22 ± 0.88 and 3.18 ± 0.89 mm, respectively,P< 0.001) and angulation (4.27 ± 2.30 and 6.82 ± 2.71°, respectively,P= 0.001). The limitations of guided surgery were discussed while considering the findings from the drop-out group.Conclusions: Computer-guided surgery demonstrates greater accuracy in implant placement with the flapless approach. Further research should be conducted to enhance the availability of guides for cases with unfavorable residual bone conditions.

The purpose of this study is to evaluate the degree of spontaneous bone healing after cyst enucleation as well as its contributing factors. Pre- and post-operative computed tomography (CT) scans of consecutive patients who had undergone jaw cyst enucleation were retrospectively analyzed. The outcome variable was healing ratio, which was calculated using the volume of the cyst before surgery and the volume of the defect in the bone after surgery. Predictor variables including duration of observation, pre-operative cyst size, age, gender, and involved jaw were analyzed to determine their influence. Forty-four subjects (30 Male and 14 Female, average 40.7 ± 15.7 years) were included in this study. Healing ratio was significantly lower during the first year (33.5 ± 32.8%) compared to the second (74.5 ± 24.2%) and subsequent years (74.2 ± 17.8%). In 35 patients who had follow-ups of over 1 year, the healing ratio was not affected by the pre-operative cyst size and upper/lower jaw except gender (p = 0.037, female > male) and age (p = 0.021, younger than 30 years > 30 years and older). The residual defect was significant larger in cysts 3 cc or larger (1.64 ± 1.54 cc) compared to smaller cysts (0.43 ± 0.42 cc, p = 0.006). The residual defect volume of large cysts was similar to those of the pre-operative volume of small cysts (1.47 ± 0.72 cc). In conclusion, spontaneous bone healing ratio of post-enucleation defects was about 73.5% after 12 months. Large cysts (> 3 cc) had larger defect, comparable to the volume of small cysts, but with altered contour. Additional treatment such as a bone graft may be considered especially in large cysts.