• Journal of Periodontal and Implant Science
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• 제49권3호
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• pp.171-184
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• 2019

Purpose: To evaluate the effects of intra-alveolar socket grafting, subepithelial connective tissue grafts, and individualized abutments on peri-implant hard and soft tissue outcomes following immediate implant placement. Methods: This randomized experimental study employed 5 mongrel dogs, with 4 sites per dog (total of 20 sites). The mesial roots of P3 and P4 were extracted in each hemimandible and immediate dental implants were placed. Each site was randomly assigned to 1 of 4 different treatment groups: standardized healing abutment (control group), alloplastic bone substitute material (BSS) + standardized healing abutment (SA group), BSS + individualized healing abutment (IA group), and BSS + individualized healing abutment + a subepithelial connective tissue graft (IAG group). Clinical, histological, and profilometric analyses were performed. The intergroup differences were calculated using the Bonferroni test, setting statistical significance at P<0.05. Results: Clinically, the control and SA groups demonstrated a coronal shift in the buccal height of the mucosa ($0.88{\pm}0.48mm$ and $0.37{\pm}1.1mm$, respectively). The IA and IAG groups exhibited an apical shift of the mucosa ($-0.7{\pm}1.15mm$ and $-1.1{\pm}0.96mm$, respectively). Histologically, the SA and control groups demonstrated marginal mucosa heights of $4.1{\pm}0.28mm$ and $4.0{\pm}0.53mm$ relative to the implant shoulder, respectively. The IA and IAG groups, in contrast, only showed a height of 2.6mm. In addition, the height of the mucosa in relation to the most coronal buccal bone crest or bone substitute particles was not significantly different among the groups. Volumetrically, the IA group ($-0.73{\pm}0.46mm$) lost less volume on the buccal side than the control ($-0.93{\pm}0.44mm$), SA ($-0.97{\pm}0.73mm$), and IAG ($-0.88{\pm}0.45mm$) groups. Conclusions: The control group demonstrated the most favorable change of height of the margo mucosae and the largest dimensions of the peri-implant soft tissues. However, the addition of a bone substitute material and an individualized healing abutment resulted in slightly better preservation of the peri-implant soft tissue contour.

• Journal of Periodontal and Implant Science
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• 제32권2호
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• pp.339-350
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• 2002

Recently the esthetic demands of clinicians and patients made the surgeon try to regenerate bone defects and gingival tissue after extraction. For that, many surgical methods were used and socket preservation have been evaluated simple, effective and good prognosis in the implant placement. Bone grafting was one of the methods for socket preservation. This study was to evaluate the histologic view of the effects on healing of the extraction sockets when deproteinized bovine bone mineral and tetracycline coated deproteinized bovine bone mineral was implanted 1. In control group, at 4 weeks after implantation, the extraction sockets were filled with connective tissue. And after 8 weeks, osteoblasts were observed in newly formed trabecular among the fibrous connective tissue in the extraction sockets. 2. In experimental 1 group, there was connective tissue and new bone trabecular around newly formed woven bone at 4 weeks. And many osteoblasts were observed in various direction at 8 weeks. 3. In experimental 2 group, there was a lot of new bone made around the bone powder after 4 weeks, and the thicker bone trabecular, lamellar bone and irregular osteoblasts arrangement were observed at 8 weeks. From the results of this study, tetracycline coated BBP would be better than the other groups in the lamellar bone formation and be faster in the bone formation rate.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권4호
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• pp.282-291
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• 2004

Pure-phase beta-tricalcium phosphate(${\beta}$-TCP) proved to be a bone regeneration material, providing the patient with vital bone at the defect site in a reasonable time, making a second surgical procedure for bone harvesting unnecessary. This study compares bone healing and BMP 2/4 expression in cranial defects in rabbits grafted with autogenous bone and ${\beta}$-TCP. Thirty New Zealand White rabbits was divided into 3 group of 10 animals each. Bilateral calvarial defects were made in the parietal bones of each animal. ${\beta}$-TCP placed in one defect and the other defects was filled with autogenous bone. The animal were sacrificed at 4, 8 and 12 weeks. Immunohistochemical analysis was used to investigate the expression of BMP 2/4. 1. The new bone formation around autogenous bone from 4 weeks and ${\beta}$-TCP from 8 weeks. 2. In autogenous bone graft, BMP 2/4 expression was decreased from 4 to 12 weeks. 3. In ${\beta}$-TCP graft, BMP 4 expression was increased from 8 to 12 weeks. But, BMP 2 was observed from 12 weeks. This study showed that bone healing, regeneration and, BMP 2/4 expression are delayed in grafted ${\beta}$-TCP than autogenous bone.

• 구강생물연구
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• 제42권4호
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• pp.198-207
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• 2018

Guided tissue regeneration (GBR) has been used to promote new bone formation in alveolar bone reconstruction at defective bone sites following tooth loss. Bone grafts used in GBR can be categorized into autogenous, xenogenous, and synthetic bones, and human allografts depending on the origin. The purpose of this study was to compare the rates of bone regeneration using two different bone grafts in the cranial defects of rabbits. Ten New Zealand rabbits were used in this study. Four defects were created in each surgical site. Each defect was filled as follows: with nothing, using a 50% xenograft and 50% human freeze-dried bone allograft (FDBA) depending on the volume rate, human FDBA alone, and xenograft alone. After 4 to 8 weeks of healing, histological and histomorphometric analyses were carried out. At 4 weeks, new bone formation occurred as follows: 18.3% in the control group, 6.5% in group I, 8.8% in group II, and 4.2% in group III. At 8 weeks, the new bone formation was 14.9% in the control group, 36.7% in group I, 39.2% in group II, and 16.8% in group III. The results of this study suggest that the higher the proportion of human FDBA in GBR, the greater was the amount of clinically useful new bone generated. The results confirm the need for adequate healing period to ensure successful GBR with bone grafting.

• 대한치과보철학회지
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• 제44권3호
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• pp.314-324
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• 2006

Statement of problem. Osseointegration is important mechanism of dental implant but it is not easy to evaluate. Indirect measurement is non-invasive and clinically applicable but they need more study about correlation between indirect values and degree of osseointegration. Purpose. The aims of this study were to evaluate the coefficient of correlation between indirect measurement and direct measurement under different healing time, and assessment of effect of initial insertion torque to the implant stability. Material and Methods. 20 rabbits received 3 implants on each side of tibia. Three kinds of implants (machined surface implant, Sandblasted with Large grit and Acid etched implant, Resorbable Blast Media treated implant) were used. During the surgery implant insertion torque were measured with $Osseocare^{TM}$. After the 1, 4, 8, 12 weeks of healing time, animals were sacrificed and stability values (Implant Stability Quotient with $Osstell^{TM}$, removal torque with torque gauge) were measured. Results. The Bone quality of rabbit tibia was classified into 2 groups according to the insertion torque. Resonance frequency analysis (ISQ) and removal torque showed positive correlation until $4^{th}$ week (r=0.555, p=0.040). After $8^{th}$ week (r=0.011, p=0.970) the correlation became weak and it turned negative at $12^{th}$ week (r=-0.074, p=0.801). Insertion torque and ISQ showed changing correlation upon the healing time ($1^{st}$ week: r=0.301, p=0.033, $4^{th}$ week: r=-0.429, p=0.018, $8^{th}$ week: r=0.032, p=0.865, $12^{th}$ week: r=-0.398, p=0.029). Insertion torque and removal torque has positive correlation but it was not statistically significant ($1^{st}$ week: r=0.410, p=0.129, $4^{th}$ week: r=0.156, p=0.578, $8^{th}$ week: r=0.236, p=0.398, $12^{th}$ week: r=0.260, p=0.350). Conclusion. In this study, bone quality may affect the degree of osseointegration positively during healing time and correlation between ISQ and degree of osseointegration can be different according to the healing time and bone quality.

• Journal of Korean Dental Science
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• 제17권2호
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• pp.53-63
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• 2024

Purpose: To investigate the effects of simultaneous soft and hard tissue augmentation and the addition of polydeoxyribonucleotide (PDRN) on regenerative outcomes. Materials and Methods: In five mongrel dogs, chronic ridge defects were established in both mandibles. Six implants were placed in the mandible, producing buccal dehiscence defects. The implants were randomly allocated to one of the following groups: 1) control: no treatment; 2) GBR: guided bone regeneration (GBR) only; 3) GBR/PDRN: GBR+PDRN application to bone substitute particles; 4) GBR/CTG: GBR+connective tissue grafting (CTG); 5) GBR/VCMX: GBR+soft tissue augmentation using volume stable collagen matrix (VCMX); and 6) group GBR/VCMX/PDRN: GBR+VCMX soaked with PDRN. The healing abutments were connected to the implants to provide additional room for tissue regeneration. Submerged healing was achieved. The animals were euthanized after four months. Histological and histomorphometric analyses were then performed. Results: Healing abutments were gradually exposed during the healing period. Histologically, minimal new bone formation was observed in the dehiscence defects. No specific differences were found between the groups regarding collagen fiber orientation and density in the augmented area. No traces of CTG or VCMX were detected. Histomorphometrically, the mean tissue thickness was greater in the control group than in the other groups above the implant shoulder (IS). Below the IS level, the CTG and PDRN groups exhibited more favorable tissue thickness than the other groups. Conclusion: Failure of submerged healing after tissue augmentation deteriorated the tissue contour. PDRN appears to have a positive effect on soft tissues.

• Journal of Korean Neurosurgical Society
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• 제50권1호
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• pp.17-22
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• 2011

Objective : In the present study, authors retrospectively reviewed the clinical outcomes of halo-vest immobilization (HVI) versus surgical fixation in patients with odontoid fracture after either non-surgical treatment (HVI) or with surgical fixation. Methods : From April 1997 to December 2008, we treated a total of 60 patients with upper cervical spine injuries. This study included 31 (51.7%) patients (22 men, 9 women; mean age, 39.3 years) with types II and III odontoid process fractures. The average follow-up was 25.1 months. We reviewed digital radiographs and analyzed images according to type of injury and treatment outcomes, following conservative treatment with HVI and surgical management with screw fixation. Results : There were a total of 31 cases of types II and III odontoid process fractures (21 odontoid type II fractures, 10 type III fractures). Fifteen patients underwent HVI (10 type II fractures, 5 type III fractures). Nine (60%) out of 15 patients who underwent HVI experienced successful healing of odontoid fractures. The mean period for bone healing was 20.2 weeks. Sixteen patients underwent surgery including anterior screw fixation (6 cases), posterior C1-2 screw fixation (8), and transarticular screw fixation (2) for healing the odontoid fractures (11 type II fractures, 5 type III fractures). Fifteen (93.8%) out of 16 patients who underwent surgery achieved healing of cervical fractures. The average bone healing time was 17.6 weeks. Conclusion : The overall healing rate was 60% after HVI and 93.8% with surgical management. Patients treated with surgery showed a higher fusion rate and shorter bony healing time than patients who received HVI. However, prospective studies are needed in the future to define better optimal treatment and cost-effective perspective for the treatment of odontoid fractures.

• Journal of Periodontal and Implant Science
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• 제29권1호
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• pp.233-249
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• 1999

Primary fixation is one of the most important factor in establishing adequate osseointegration between implant and bone. To evaluate the initial healing response of bone around implants without primary bone contact, this study was designed to create considerable space between implant and bone in 5 mongrel dogs, about 1-year old. After 3 holes of 6.0mm in diameter were prepared at the femur neck of the dogs, commercially pure titanium thread type implants(STERI-$OSS^{(R)}$), 8mm in length and 3.8mm, 5.0mm and 6.0mm in diameter, were inserted. Implants were supported by only nonresorbable membrane($Teflon^{(R)}$), and the penetration of upper soft tissue into the gap was inhibited by it. The each implant was positioned in the center of the drilled hole. 9 implants with different diameters were inserted in 3 dogs for histologic observation, and 12 were inserted in 2 dogs for mobility test and removal torque test.Fluorescent dyes were injected in order of Doxycycline, Alizarin Red S, and Calcein at intervals of 2 weeks. At 4-, 8-, and 12-week after placement, 3 dogs were sacrificed for histologic observation, and at 8- and 12-week after placement, 2 dogs were sacrificed for mobility test using $Periotest^{(R)}$ (Simens AG, Bensheim, Germany) and torque test using Autograph AGS-1000D $series^{(R)}$(Japan). The result were as follows: 1. The wider the gap between bone and implant was, the less bone maturity was, and the later osseointegration was occurred. Trabecular direction of new bone around implant was changed from parallel to perpendicular to the implant, and the gap was filled with new bone, over time. 2. There was a decreasing tendency over time in the mobility of all implants, but the wider gap between bone and implant was, the smaller decrease of the mobility was. 3. There was a increasing tendency over time in the removal torque gauge of all implants, and the wider gap was, the smaller increase of the removal torque gauge was. The results suggest that osseointegration in case of implant without primary bone contact may be obtained by guided bone regeneration technique with prolonged healing period, but the time of second surgery should be considered carefully.

• Imaging Science in Dentistry
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• 제34권4호
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• pp.191-194
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• 2004

This report is to show healing process of two cases of buccal bifurcation cyst (BBC) developed from the mandibular deciduous second molars. Extracting the involved deciduous teeth led to marsupialization of the cysts and promoted eruption of the associated successors without orthodontic force. The cyst-associated premolars in the two cases erupted faster than the premolars on the contralateral noncyst side. The cysts were completely filled with normal bone. The monitoring radiographs showed bone healing, root formation, and path of eruption of the associated teeth after marsupialization of BBC.

• Journal of Periodontal and Implant Science
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• 제31권1호
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• pp.57-74
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• 2001

The purpose of this study was to evaluate the adjunctive combined effect of demineralized freeze-dried bone allograft(DFDB) in guided bone regeneration on supra-alveo-lar peri-implant defect. Supra-alveolar perio-implant defects, 3mm in height, each including 4 IMZ titanium plasma-sprayed implants were surgically created in two mongrel dogs. Subsequently, the defects were treated with 1 of the following 3 modalities: Control) no membrane or graft application, Group1) DFDB application, Group2) guided bone regeneration using an expanded polytetra-fluoroethylene membrane, Group3) guided bone regeneration using membrane and DFDB. After a healing period of 12-week, the animals were sacrificed, tissue blocks were harvested and prepared for histological analysis. Histologic examination were as follows; 1. New bon formation was minimal in control and Group 1, but considerable new bone formation was observed in Group 2 and Group 3. 2. There was no osteointegration at the implant-bone interface in the high-polished area of group2 and Group 3. 3. In fluorescent microscopic examination, remodeling of new bone was most active during week 4 and week 8. There was no significant difference in remodeling rate between group 2 and group 3. 4. DFDB particles were observed, invested in a connective tissue matrix. Osteoblast activity in the area was minimal. The results suggest that guided bone regeneration shows promising results in supra-alveolar peri-implant defects during the 12 week healing period although it has a limited potential in promoting alveolar bone regeneration in the high-polished area. There seems to be no significant adjunctive effect when DFDB is combined with GBR.