• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.5
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• pp.217-223
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• 2013

Objectives: Buccal fracture of the mandibular proximal bone segment during bilateral sagittal split ramus osteotomy (SSRO) reduces the postoperative stability. The primary aim of this study is to evaluate the effect of this type of fracture on bone healing and postoperative stability after mandibular setback surgery. Materials and Methods: Ten patients who experienced buccal fracture during SSRO for mandibular setback movement were evaluated. We measured the amount of bone generation on a computed tomography scan, using an image analysis program, and compared the buccal fracture side to the opposite side in each patient. To investigate the effect on postoperative stability, we measured the postoperative relapse in lateral cephalograms, immediately following and six months after the surgery. The control group consisted of ten randomly-selected patients having a similar amount of set-back without buccal fracture. Results: Less bone generation was observed on the buccal fracture side compared with the opposite side (P<0.05). However, there was no significant difference in anterior-posterior postoperative relapse between the group with buccal fracture and the control group. The increased mandibular plane angle and anterior facial height after the surgery in the group with buccal fracture manifested as a postoperative clockwise rotation of the mandible. Conclusion: Bone generation was delayed compared to the opposite side. However, postoperative stability in the anterior-posterior direction could be maintained with rigid fixation.

• Journal of Periodontal and Implant Science
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• v.52 no.4
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• pp.312-324
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• 2022

Purpose: The role of hard-type crosslinked hyaluronic acid (HA) with particulate bone substitutes in bone regeneration for combined inlay-onlay grafts has not been fully investigated. We aimed to evaluate the effect of hard-type crosslinked HA used with bone substitute in terms of new bone formation and space maintenance. Methods: A 15-mm-diameter round defect was formed in the calvaria of 30 New Zealand White rabbits. All animals were randomly assigned to 1 of 3 groups: the control group (spontaneous healing without material, n=10), the biphasic calcium phosphate (BCP) graft group (BCP, n=10), and the BCP graft with HA group (BCP/HA, n=10). The animals were evaluated 4 and 12 weeks after surgery. Half of the animals from each group were sacrificed at 4 and 12 weeks after surgery. Samples were evaluated using micro-computed tomography, histology, and histomorphometry. Results: The BCP group showed higher bone volume/tissue volume (BV/TV) values than the control and BCP/HA groups at both 4 and 12 weeks. The BCP and BCP/HA groups showed higher bone surface/tissue volume (BS/TV) values than the control group at both 4 and 12 weeks. The BCP group showed higher BS/TV values than the control and BCP/HA groups at both 4 and 12 weeks. No statistically significant difference in newly formed bone was found among the 3 groups at 4 weeks. The BCP group showed significantly higher new bone formation than the BCP/HA group at 12 weeks. Conclusions: Hard-type crosslinked HA did not show a positive effect on new bone formation and space maintenance. The negative effect of hard-type crosslinked HA may be due to the physical properties of HA that impede osteogenic potential.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.6
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• pp.467-477
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• 2011

Purpose: The objective of this study was to examine the affected period and the amount of bone formation during osteogenesis of intramembranous bone using low-intensity pulsed ultrasound (LPUS) $in$ $vivo$. Methods: Xeno-bone (Bio-oss) and autogenous bone were grafted bilaterally into mini-pig mandibles. The left mandible served as the control and the other mandible was treated with 3 MHz, 160 mW (output, 0.8 mW) ultrasound stimulation for 7 days 15 minutes per day. The mini-pigs were sacrificed at 1, 2, 4, and 8 weeks, and micro computed tomography (${\mu}CT$), a microscopic examination, and a statistical analysis were performed on the specimens. Results: Based on a computerized image analysis of the ${\mu}CT$ scans, the experimental group had an average 150% more new bone formation than that in the control group. The effect of LPUS continued during the post operative 2 weeks. The histomorphological microscopic examination showed similar results. Conclusion: Our results suggest the LPUS had an effect on early intramembranous bone formation in vivo.

• Journal of Korean Dental Science
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• v.3 no.1
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• pp.11-16
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• 2010

Objective : This prospective study sought to verify the stability of three types of short implants measuring 7mm or less. Materials and methods : Implants measuring 7mm or less were placed in patients at multicenter dental clinics in Korea, China, Taiwan, and Singapore. Initial stability, intraoperative and postoperative complications, crestal bone loss, and survival rate of the implant were prospectively evaluated. Results : The primary stability of a 6-mm implant was lower than that of a 7-mm implant. The marginal bone loss of short implants measuring less than 7mm was minimal. Complications such as wound dehiscence, implant mobility, and peri-implant mucositis developed, and these were associated with initial implant failure. The short-term survival rate of 6-mm implant was 93.7%, and that of 7-mm implant, 96.6%. Conclusion : Short implant for the mandible with insufficient height for the residual ridge can be selectively used. Poor primary stability and wound dehiscence can cause osseointegration failure and alveolar bone loss.

• Journal of Periodontal and Implant Science
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• v.46 no.2
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• pp.72-83
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• 2016

Purpose: The goal of this study was to evaluate the long-term success of horizontal alveolar crest augmentation of the retromolar region of the mandible with particulated bone, as well as factors affecting subsequent peri-implant bone loss. Methods: A total of 109 patients (68 female, 41 male) suffering from alveolar ridge deficiencies of the maxilla and mandible were included in this study. All patients were treated with particulated retromolar bone grafts from the mandible prior to the insertion of endosseous dental implants. Mesial and distal peri-implant crestal bone changes were assessed at six time points. Several parameters, including implant survival and the influence of age, gender, localisation of the implant, diameter, covering procedures, and time points of implant placement, were analysed to identify associations with bone level changes using the Mann-Whitney U-test, the Kruskal-Wallis test, and Spearman's rank-order correlation coefficient. Results: A total of 164 dental implants were placed in the maxilla (n=97) and in the mandible (n=67). The mean observation period was $105.26{\pm}21.58$ months after implantation. The overall survival rate was 97.6% after 10 years. Overall, peri-implant bone loss was highest during the first year, but decreased over time. The mean amount of bone loss after 10 years was 2.47 mm mesially and 2.50 mm distally. Bone loss was significantly influenced by implant type and primary stability. Conclusions: The use of particulated autologous retromolar bone grafts is a reliable technique for the horizontal reconstruction of local alveolar ridge deficiencies. Our results demonstrate that implants placed in augmented bone demonstrated similar bone level changes compared to implants inserted in non-augmented regions.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.6
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• pp.616-621
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• 2008

Osseointegration is a result of bone formation and bone regeneration processes, which takes place at the interface between bone and implant, and it indicates a rigid fixation that can be stably maintained while functional loading is applied inside the oral cavity as well as after implant placement. Although many researches were carried out about osseointegration mechanism, but cellular and molecular events have not been clarified. With recent development of molecular biology, some researches have examined biological determinants, such as cytokine, growth factors, bone matrix proteins, during osseointegration between bone and implant surface, other researches attempted to study the ways to increase bone formation by adhering protein to implant surface or by inserting growth factors during implant placement. Cellular research on the reaction of osteoblast especially to surface morphology (e.g. increased roughness) has been carried out and found that the surface roughness of titanium implant affects the growth of osteoblast, cytokine formation and mineralization. While molecular biological research in dental implant is burgeoning. Yet, its results are insignificant. We have been studying the roles of growth factors during osseointegration, comparing different manifestations of growth factors by studying the effect of osseointegration that varied by implant surface. Of many growth factors, $TGF-{\beta}$, IGF-I, BMP2, and BMP4, which plays a significant role in bone formation, were selected, and examined if these growth factors are manifested during osseointegration. The purpose of this article is to present result of our researches and encourage molecular researches in dental implant.

• Journal of Periodontal and Implant Science
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• v.47 no.4
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• pp.194-210
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• 2017

Purpose: The aim of the present study was to evaluate the healing of post-extraction sockets following alveolar ridge preservation clinically, radiologically, and histologically. Methods: Overall, 7 extraction sockets in 7 patients were grafted with demineralised bovine bone mineral and covered with a porcine-derived non-crosslinked collagen matrix (CM). Soft tissue healing was clinically evaluated on the basis of a specific healing index. Horizontal and vertical ridge dimensional changes were assessed clinically and radiographically at baseline and 6 months after implant placement. For histological and histomorphometric analysis, bone biopsies were harvested from the augmented sites during implant surgery 6 months after the socket preservation procedure. Results: Clinically, healing proceeded uneventfully in all the sockets. A trend towards reduced horizontal and vertical socket dimensions was observed from baseline to the final examination. The mean width and height of resorption were 1.21 mm (P=0.005) and 0.46 mm (P=0.004), respectively. Histologically, residual xenograft particles ($31.97%{\pm}3.52%$) were surrounded by either newly formed bone ($16.02%{\pm}7.06%$) or connective tissue ($50.67%{\pm}8.42%$) without fibrous encapsulation. The CM underwent a physiological substitution process in favour of well-vascularised collagen-rich connective tissue. Conclusions: Socket preservation using demineralised bovine bone mineral in combination with CM provided stable dimensional changes of the alveolar ridge associated with good reepithelialisation of the soft tissues during a 6-month healing period.

• Journal of Periodontal and Implant Science
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• v.49 no.6
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• pp.382-396
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• 2019

Purpose: The purpose of this study was to elucidate the efficacy and safety of carbonate apatite (CO₃Ap) granules in 2-stage sinus floor augmentation through the radiographic and histomorphometric assessment of bone biopsy specimens. Methods: Two-stage sinus floor augmentation was performed on 13 patients with a total of 17 implants. Radiographic assessment using panoramic radiographs was performed immediately after augmentation and was also performed 2 additional times, at 7±2 months and 18±2 months post-augmentation, respectively. Bone biopsy specimens taken from planned implant placement sites underwent micro-computed tomography, after which histological sections were prepared. Results: Postoperative healing of the sinus floor augmentation was uneventful in all cases. The mean preoperative residual bone height was 3.5±1.3 mm, and this was increased to 13.3±1.7 mm by augmentation with the CO₃Ap granules. The mean height of the augmented site had decreased to 10.7±1.9 mm by 7±2 months after augmentation; however, implants with lengths in the range of 6.5 to 11.5 mm could still be placed. The mean height of the augmented site had decreased to 9.6±1.4 mm by 18±2 months post-augmentation. No implant failure or complications were observed. Few inflammatory cells or foreign body giant cells were observed in the bone biopsy specimens. Although there were individual differences in the amount of new bone detected, new bone was observed to be in direct contact with the CO₃Ap granules in all cases, without an intermediate layer of fibrous tissue. The amounts of bone and residual CO₃Ap were 33.8%±15.1% and 15.3%±11.9%, respectively. Conclusions: In this first demonstration, low-crystalline CO₃Ap granules showed excellent biocompatibility, and bone biopsy showed them to be replaced with bone in humans. CO₃Ap granules are a useful and safe bone substitute for two-stage sinus floor augmentation.

• The Journal of the Korean dental association
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• v.46 no.4
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• pp.222-231
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• 2008

Various maxillary sinus floor augmentation techniques were common performed and in the most cases, many kinds of bone graft materials were used. The graft materials are autogenous bone or other biomaterials of human, animal or synthetic origin. But these cases report describes a new surgical technique by which dental implants are inserted in a void space created by elevating the sinus membrane without additional graft material in atrophic posterior maxilla. We created lateral bony window using piezoelectric device and elevated the schneiderian membrane in five patients and was repositioned with bony window in five patients, without any bone graft. From the clinical and histological results, it is found there is potential capacity for bone formation and placement of implants in the maxillary sinus without the use of bone grafts or bone substitutes.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.8.1-8.6
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• 2015

Background: This study aimed to evaluate the clinical usefulness of autogenous fresh demineralized tooth (auto-FDT) graft prepared at the chairside for alveolar bone grafting during dental implant surgery. Methods: In total, 38 patients requiring both tooth extraction (for endodontic or periodontal reasons or third molar extraction) and alveolar bone regeneration for dental implant placement were included. Within 2 h after clean extraction, the teeth were prepared at the chairside to serve as bone graft material. In the same sitting, blocks or chips of this graft material were used to reconstruct defects at the osteotomy site simultaneously with or before implant placement. Twelve months after prosthesis fabrication and placement, the clinical findings and implant success rates were evaluated. Histological studies were randomly conducted for selected cases. Results: Clinical evaluation showed favorable wound healing with minimal complications and good bone support for the implants. No implant was lost after 12 months of function following prosthetic rehabilitation. Histological examination revealed new bone formation induced by the graft material. Conclusions: Chairside preparation of autogenous fresh demineralized teeth after extraction can be a useful alternative to the use of autogenous bone or other graft materials for the immediate reconstruction of alveolar bone defects to facilitate subsequent implant placement.