• Journal of Periodontal and Implant Science
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• v.49 no.1
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• pp.39-46
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• 2019

Purpose: This study aimed to evaluate the effects of i) the extent of peri-implant bone defects and ii) the application of bone cement on implant stability with respect to the measurement direction. Methods: In 10 bovine rib bones, 4 implant osteotomies with peri-implant bone defects of various widths were prepared: i) no defect (D0), ii) a 2-mm-wide defect (D2), iii) a 4-mm-wide defect (D4), and iv) a 8-mm-wide defect (D8). The height of all defects was 10 mm. Implant stability quotient (ISQ) values and Periotest values (PTVs) were measured after implant placement and bone cement application. Results: With increasing defect width, decreased ISQs and increased PTVs were observed. Statistically significant differences were found between groups D0 and D8, D0 and D4, and D2 and D8. Prior to bone cement application, inconsistent PTVs were found in group D8 depending on the measurement direction. Bone cement increased the implant stability. Conclusion: Peri-implant bone deficits measuring around 50% of the implant surface compromised implant stability. Clinically, PTVs should be cautiously interpreted in implants with large peri-implant defects due to inconsistent recordings with respect to the measurement direction.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.1
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• pp.49-53
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• 2011

Introduction: This study compared the strength of osseointegration as determined by the resistance to reverse torque rotation of three different hydroxyapatite coated implants in the rabbit femur model. Materials and Methods: Three hydroxyapatite coated implants (HAPTITE), Tapered Screw-Vent (TSV) and BioTite-H - were used. A total of 40 implants were placed in the femur of 20 adult male rabbits. The animals were divided into two groups. In group A (n=10); one HAPTITE was placed into each right femur and one TSV was placed into each left femur. In group B (n=10); one HAPTITE was placed into each right femur and one BioTite-H was placed into each left femur. Five rabbits of each group were sacrificed at 4 and 8 weeks. The implants were removed by reverse torque rotation using a digital torque-measuring device. A total of 40 implants in 20 rabbits were used for the removal torque measurements. Results: In the Group A, 4 weeks after implant placement, the mean removal torque for the HAPTITE and TSV was $70.7{\pm}31.6$ N cm and $28.9{\pm}15.1$ N cm, respectively. Eight weeks after implant placement, the mean removal torque for the HAPTITE and TSV was $87.9{\pm}26.2$ N cm and $54.9{\pm}22.4$ N cm, respectively. In the Group B, 4 weeks after implant placement, the mean removal torque for the HAPTITE and BioTite-H was $58.0{\pm}29.6$ N cm and $37.7{\pm}14.1$ N cm, respectively. Eight weeks after implant placement, the mean removal torque for the HAPTITE and BioTite-H was $91.4{\pm}47.1$ N cm and $30.8{\pm}9.8$ N cm. HAPTITE showed a higher removal torque than the other implants. Conclusion: These results suggest that HAPTITE increases the strength of osseointegration significantly as determined by the resistance to reverse torque rotation.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.135-142
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• 2008

Purpose: Numerous studies have shown that crestal bone resorption around the implant was related to the location of the implant abutment junction(IAJ). Recently it was hypothesized that platform switching termed the inward horizontal repositioning of the IAJ might limit bone resorption around the implants. The purpose of this clinical study was to evaluate the effect of platform switching on crestal bone resorption. Materials and Methods: The crestal bone loss of 65 external hex implants in 26 patients were radiographically measured at crown placement and follow-up examinations. 23 standard implants(non-platform switching group, NP) were connected with the matching abutments and 42 wide implants(platform switching group, PS) were connected with the 1 mm smaller diameter abutments. Results: There was significant difference of crestal bone loss between NP group and PS group. For implants in the NP group, mean crestal bone loss was $1.18{\pm}0.68\;mm$ at crown placement and $1.42{\pm}0.41\;mm$ at follow-up. The meal bone loss in PS group was $0.47{\pm}0.52\;mm$ at crown placement and $0.60{\pm}0.65\;mm$ at follow-up. When the crestal bone changes according to placement depths of implants were compared, subcrestal position of IAJ had a significantly less bone loss in PS group, but it was not in NP group. Conclusion: Within the limits of the present study, it was concluded that platform switching technique might decrease crestal bone loss around the implants. Additionally, when the IAJ of implant was placed 1 mm deeper in the alveolar bone, the effect of platform switching on bone loss was enhanced.

• The Journal of Advanced Prosthodontics
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• v.16 no.4
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• pp.212-220
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• 2024

PURPOSE. This cone-beam computed tomography (CBCT) study aimed to analyze the anatomical characteristics of alveolar bone at mandibular first molar (MFM) and their implications for immediate implant placement surgery. MATERIALS AND METHODS. 100 patients with 140 MFMs were reviewed retrospectively. We first performed a 3D reconstruction of the patient's CBCT data to determine a reference plane with ideal implant placement and orientation. The following parameters of MFM region were analyzed: mesial-distal socket size (MDSS), buccal-lingual socket size (BL-SS), root furcation fornix to inferior alveolar nerve (IAN) distance (RF-I), interradicular bone thickness (IRB), mesial/distal root apex to the IAN distance (MRA-I/DRA-I), thickness of the buccal/lingual bone of the mesial root (MR-B/MR-L), thickness of the buccal/lingual bone of the distal root (DR-B/DR-L). RESULTS. The MD-SS of MFM was 8.74 ± 0.76 mm, and the BLSS was 8.26 ± 0.72 mm. The MR-B, DR-B was 1.01 ± 0.40 mm and 1.14 ± 0.50 mm, and the difference was statistically significant (P = .001). The values of the MR-L, DR-L were 2.71 ± 0.78 mm and 3.09 ± 0.73 mm, and the difference was also statistically significant (P < .001). The mean distance of RF-I was 15.68 ± 2.13 mm, and the MRA-I was 7.06 ± 2.22 mm, which was greater than that of DRA-I (6.48 ± 2.30 mm, P < .001). The IRB at 2 mm, 4 mm apical from the furcation fornix, and at apex level was 2.81 ± 0.50 mm, 3.30 ± 0.62 mm, and 4.44 ± 1.02 mm, respectively. CONCLUSION. There is relatively sufficient bone mass in interradicular bone in height, but an adequate width is lacking for the bone between the mesial and distal root after the extraction of the MFM for immediate implantation. The thickness of the MFM buccal bone is relative thin, especially for the mesial root.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.187-197
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• 2005

The aim of this study was to investigate the influence of peri-implant soft tissue and bone thickness on the early dimensional change of peri-implant soft tissue. Seventy-seven non-submerged implants of 39 patients which had been loaded more than 6 months were selected for the study. Following clinical parameters were measured; bucco-lingual bone width of the alveolar bone for implant placement before implant surgery; distance between implant shoulder and the first bone/implant contact at the surgery; presence of plaque, probing depth, bleeding on probing, width of keratinized mucosa, mucosa thickness, distance between implant shoulder and peri-implant mucosa, crown margin location at follow-up examination. The results showed that distance between implant shoulder and peri-implant mucosa (DIM) was correlated with probing depth and width of keratinized mucosa (p < 0.05). In addition, mucosa thickness was also correlated with probing depth (p<0.05). However, the bone width of alveolar bone and soft tissue thickness were not found to be correlated with DIM. It is important to understand the meaning of peri-implant tissue dimension in relation to dimensional changes of peri-implant soft tissue which designates appearance of implant-supported restorations. Future study is needed to elucidate the significance of the buccal bone thickness and soft tissue thickness with respect to the change of peri-implant soft tissue margin with the use of an instrument capable of measuring buccal bone thickness directly.

• Journal of Periodontal and Implant Science
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• v.29 no.2
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• pp.415-433
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• 1999

Implant stability is the key to long-term successful outcome for osseointegrated implants. To evaluate the initial healing response of bone around HA-coated implants without primary bone contact. 21 HA-coated thread type implants(STERI-OSS?) were placed in the femurs of 5 mongrel dogs, about 1-year old. Implants, 8 mm in length and 3.8mm(experimental 1group), 5.0mm(experimental 2group) and 6.0mm(control group) in diameter, were inserted after 3 holes of 6.0mm in diameter and 10mm in depth were prepared in the surgical sites each dog. Implants were supported by only nonresorbable membrane($Teflon^{(R)}$), in order to prevent the ingrowth of upper soft tissue into the gap between bone and implant, and to maintain each implant to be positioned in the center of the drilled hole. 9 implants with different diameters were inserted in 3 dogs for histologic observation, and 12 implants were inserted in 2 dogs for mobility test and removal torque test. Fluorescent dyes were injected for the observation of new bone formation in order of $Terramycin^{(R)}$, Arizarin $Red^{(R)}$, and $Calcein^{(R)}$ at an interval of 2 weeks. 3 dogs were sacrificed for histologic observation at 4, 8, and 12-week after placement. Light microscopy and confocal laser scanning microscopy were used to qualitatively characterize the bone around HA-coated implant. 2 dogs were sacrificed for mobility test($Periotest^{(R)}$, Simens AG, Bensheim, Germany) and removal torque test($Autograph^{(R)}$ AGS-1000D series, Japan) at 8 and 12-week after placement The results were as follows: 1. Histologic observation showed that osseointegration occurred to both control and experimental groups as time lapse, but delayed bone healing was revealed in 3.8mm group (experimental 1group), compared to contrtol group and 5.0mm group (experimental 2group). 2. The mobility test showed that the experimental groups had no distinguishable movement during experimental periods of 8 and 12-week, and there was no difference in mobility depending on the gap between bone and implant, and time lapse. 3. The removal torque forces were increased depended on the gaps decreasing between bone and implant, and time lapse. The results suggest that HA-coated implant without primary bone contact, based on guided bone regeneration could obtain its stability in all experimental groups as time lapse, but bone healing was delayed in experimental group of 3.8mm. And the results suggested that studies on correlationship between mobility test and removal torque test for implant stability would be necessary.

• Journal of Korean Dental Science
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• v.2 no.2
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• pp.31-34
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• 2009

The survival rate of the OSSTEM GS II Implant 1 year after serving the prosthetic function in 2 domestic and foreign medical institutes was 97.57%; the success rate was 95.7%, and the average alveolar bone resorption was 0.24mm(n=389). In particular, the alveolar bone resorption occurred differently according to the placement location as well as whether or not the patient underwent bone grafting operation, but the implant s length and diameter did not have significant impact on alveolar bone resorption.

• Journal of Korean Dental Science
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• v.6 no.1
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• pp.27-33
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• 2013

The introduction of osseointegrated dental implants in dentistry brought about a new era in everyday dental practice. For the past 50 years, prosthetic restoration with implant-supported prosthesis has developed into a viable and predictable treatment option. Alongside the increasing use of dental implants is the occurrence of many complications during implant placement (surgery), in the mechanical or prosthetic problem, and in the biological aspect. In particular, abutment or screw fracture as one of the mechanical complications can put the dentist in a tight spot in a clinical situation. It is hard to remove the fractured abutment and screw to restore it properly. Therefore, it is very important that clinicians consider possible complications in advance and make an appropriate treatment plan. We discuss cases of abutment fracture and mechanical/prosthetic complications together with the causes and solutions.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.5
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• pp.284-289
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• 2015

In cases of severe alveolar bone atrophy in the posterior maxillary area, which has only a thin sinus floor, the autogenous tooth bone graft block (ABTB) was used to wrap the implant to enhance its primary stability and osseointegration in the sinus. These cases with four years of clinical follow-up demonstrate the applicability of the ABTB in maxillary sinus membrane elevation to improve the outcomes of implant placement.

• Journal of Korean Dental Science
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• v.14 no.1
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• pp.32-39
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• 2021

'Crossed occlusion' is the condition in which occlusal intercuspation is lost when several teeth on upper and lower jaw remain. This report describes a clinical case in which a patient had two upper-left posterior teeth and two lower-right posterior teeth; typically known as left-right crossed occlusion. Considering the patient's general condition and financial situation, the treatment plan included placement of two implants on each jaw against the remaining teeth using surgical guide. To find out the ideal position of implants, digital diagnostic wax-up was preceded by superimposing the cast and cone beam computed tomography image, which was aided with radiographic stents. The consequent surveyed implant bridge provided stable vertical stop for fabrication of the implant assisted removable partial dentures. The patient was satisfied with the functionality and esthetics of definitive prosthesis.