• Journal of Periodontal and Implant Science
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• v.38 no.4
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• pp.603-610
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• 2008

Purpose: The guided bone regeneration (GBR) technique is widely used in periradicular surgery. However, there is still some controversy regarding the effectiveness of GBR in promoting bone healing after periradicular surgery. The purpose of this study was to evaluate the resorbable membrane on the osteointegration of immediate implants in sites with periradicular lesion that had been removed by periradicular surgery. Materials and methods: Six roots of lower second premolars and 15 roots of lower third and fourth premolars of dogs were used as control and experimental teeth, respectively. Periradicular lesions were induced only in the experimental teeth. Twelve weeks later, the control and experimental teeth were extracted and implants were placed immediately. Periradicular lesions were removed with osteotomy, curettage and saline irrigation. Resorbable membranes were used in experimental group 1 but not in experimental group 2. After 12 week of healing period, the implants were clinically not mobile and showed no signs of infection. Data obtained by histomorphometric analysis were analyzed by Kruskal-Wallis test. Results: The control group showed a significantly higher bone to implant contact (BIC) ($74.14{\pm}16.18$) than experimental group 1 ($40.28{\pm}15.96$) and 2 ($48.70{\pm}17.75$)(p<0.05). However, there was no significant difference between experimental group 1 and 2. Conclusion: Although BIC in experimental groups were lower than in control group, immediate implant can be successfully placed at extraction socket with periradicular lesion and osseous defect. However, the use of resorbable membrane in bony defect created during periradicular surgery was questioned.

• Journal of Periodontal and Implant Science
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• v.52 no.5
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• pp.411-421
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• 2022

Purpose: In this study, we aimed to evaluate the degree of heat generation when a novel drill design with an irrigation slot was used with metal sleeve-free (MF) and metal sleeve-incorporated (MI) surgical guides in an environment similar to that of the actual oral cavity. Methods: A typodont with a missing mandibular right first molar and 21 bovine rib blocks were used. Three-dimensional-printed MF and MI surgical guides, designed for the placement of internal tapered implant fixtures, were used with slot and non-slot drills. The following groups were compared: group 1, MI surgical guide with slot drill; group 2, MI surgical guide with a non-slot drill; and group 3, MF surgical guide with a slot drill. A constant-temperature water bath at 36℃ was used. The drilling was performed in 6 stages, and the initial, highest, and lowest temperatures of the cortical bone were measured at each stage using a non-contact infrared thermometer. Results: There were no temperature increases above the initial temperature in any drilling procedure. The only significant difference between the non-slot and slot groups was observed with the use of the first drill in the MI group, with a higher temperature in the non-slot group (P=0.012). When the heat generation during the first and the second drilling was compared in the non-slot group, the heat generation during the first drilling was significantly higher (P<0.001), and there was no significant difference in heat generation between the drills in the slot group. Conclusions: Within the limitations of this study, implant-site preparation with the surgical guide showed no critical increase in the temperature of the cortical bone, regardless of whether there was a slot in the drill. In particular, the slotted drill had a cooling effect during the initial drilling.

• Journal of Periodontal and Implant Science
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• v.52 no.5
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• pp.422-434
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• 2022

Purpose: The purpose of this study was to evaluate and compare the healing patterns of 2-mm and 4-mm proximal infrabony defects adjacent to dental implants in canine mandibles. Methods: Four male beagles were used. Two groups were created: a 2-mm group (n=4) and a 4-mm group (n=4) depending on the horizontal dimension of proximal infrabony defects adjacent to implants. Bone healing patterns between the 2 groups were evaluated and compared at 8 and 16 weeks using radiographic, histological, histomorphometric, and fluorescent labelling analyses. Results: According to microcomputed tomography, the median bone volume fraction, bone mineral density, and the percentage of radiographic distance from the defect bottom to the most coronal bone-to-implant contact (radio-mcBIC) were 32.9%, 0.6 g/cm³, and 73.7% (8 weeks) and 45.7%, 0.7 g/cm³, and 76.0% (16 weeks) in the 2-mm group and 57.7%, 0.8 g/cm³, and 75.7% (8 weeks) and 50.9%, 0.8 g/cm³, and 74.7% (16 weeks) in the 4-mm group, respectively. According to histomorphometry, the median bone area fraction, mcBIC and the percentage of BIC amounted to 36.7%, 3.4 mm, and 58.4% (8 weeks) and 49.2%, 3.4 mm, and 70.2% (16 weeks) in the 2-mm group and 50.0%, 3.0 mm, and 64.8% (8 weeks) and 55.7%, 3.0 mm, and 69.6% (16 weeks) in the 4-mm group, respectively. No statistically significant differences were found between the groups for any variables (P>0.05). Conclusions: The proximal defects that measured 2 mm and 4 mm showed similar healing patterns at 8 and 16 weeks, and the top of bone formation in the defects was substantially limited to a maximum of 1.6 mm below the implant shoulder in both groups.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.1
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• pp.27-33
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• 2014

Purpose: The purpose of this study was to investigate the food impaction between implant prostheses and adjacent natural teeth. Materials and methods: For this study, 51 patients with food impaction were selected and investigated mobility, tightness of contact area, gingival index, plaque index, attachment loss, alveolar bone level, proximal caries, marginal ridge distance and occlusal relationships. Results: Food impaction was found in the upper teeth (60.7%) more than the lower teeth (39.2%). Food impaction was occurred on mesial side of implant prostheses (86.2%) more than distal side (13.7%). Food impaction was mostly found in loose or open contact area (94.2%). Food impaction was frequent on stepped relationship between implant and adjacent teeth. Conclusion: Treatment plan should include proper adjacent and antagonistic occlusal plane and occlusal surface, to prevent food impaction, and the plan should include less adjacent tooth mobility with proper tightness between implant prostheses and adjacent teeth.

• Journal of Korean Dental Science
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• v.2 no.2
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• pp.24-30
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• 2009

Two component orthodontic C-implants have been introduced as intermaxillary fixation (IMF) screws in cases of periodontal problems with bone loss, severely damaged teeth, or short roots. This retrospective research sought to investigate the complications and risk factors associated with the failure of two-part C-implants for IMF cases and to show the possible indications compared to one-component mini-implants. The study sample consisted of 46 randomly selected patients who had a total of 203 implants. Pearson chi-square tests of independence were used to test for associations among categorical variables. At least 19 of the total 203 implants failed (9.3%). There was no significant difference in implant failure due to gender, oral hygiene, and placement, although a significant difference due to soft tissue characteristics and root contact was observed. The two-component design of the mini-implant is reliable for difficult IMF cases. Note, however, that the factors influencing implant failure were found to be age, root damage, and condition of soft tissues.

• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.83-90
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• 2008

Purpose: This study investigated the osteoconductivity of natural calcium carbonate-derived bone substitutes, hen eggshell (ES), and compared with those of commercial bone substitutes. Materials and Methods: Osseous defects created in the rat calvaria were filled with particulated ES(ES-1), ES with calcium-deficient hydroxyapatite surface layer (ES-2), Biocoral(Inoteb, France), and Bio-Oss(Geistlich Pharma, Wolhusen, Switzerland). After 4 and 8 weeks of healing, histomorphometic analysis was performed to evaluate the amount of newly formed mineralized bone area (NB%). Results: Histologic and histomorphometric analysis showed new bone formation and direct bony contact with the grafted materials in all groups. At 4 weeks, Biocoral group showed greater NB% compared to Bio-Oss and ES-1 groups (P<0.05). At 8 weeks, Biocoral and ES-2 groups showed significantly greater NB% compared to Bio-Oss group (P<0.05). Conclusion: These results indicate that natural calcium carbonate-derived bone substitutes with microporous calcium-deficient hydroxyapatite surface layer may be an effective materials treating osseous defects.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.609-616
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• 2007

Purpose: The aim of the present study was to evaluate the effect of Bio-Oss on bone formation in terms of healing period and type of membrane so that determine the most suitable condition for implant fixation in grafted maxilla. Material & Method: Forty-five biopsy specimens from graft site were evaluated. Sinus lift was performed in the patients with reduced alveolar bone height(less than 5mm). The specimen was taken at the time of implant fixation, which was performed at least 5 months after the sinus lift procedure. All specimens were stained with H&E and Trichrome staining and evaluated histomorphometrically. Result: The results showed that Bio-Oss particle was in direct contact with newly formed bone in all cases. In the present study, the amount of newly formed bone and the residual bone substitute material were not statistically different according to various membrane and different healing period. There was no difference between the histological feature of the specimen of 5 and 31 months. No statistical significance was detected between male and female. Conclusion: The result implies that Bio-Oss does not seem to be resorbed over time regardless of the type of the membranes. The further investigation is needed to clarify this issue with the extended period of follow-up.

• Journal of Periodontal and Implant Science
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• v.46 no.6
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• pp.362-371
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• 2016

Purpose: The increasing demand for esthetically pleasing results has contributed to the use of ceramics for dental implant abutments. The aim of this study was to compare the biological response of epithelial tissue cultivated on lithium disilicate ($LS_2$) and zirconium oxide ($ZrO_2$) ceramics. Understanding the relevant physicochemical and mechanical properties of these ceramics will help identify the optimal material for facilitating gingival wound closure. Methods: Both biomaterials were prepared with 2 different surface treatments: raw and polished. Their physicochemical characteristics were analyzed by contact angle measurements, scanning white-light interferometry, and scanning electron microscopy. An organotypic culture was then performed using a chicken epithelium model to simulate peri-implant soft tissue. We measured the contact angle, hydrophobicity, and roughness of the materials as well as the tissue behavior at their surfaces (cell migration and cell adhesion). Results: The best cell migration was observed on $ZrO_2$ ceramic. Cell adhesion was also drastically lower on the polished $ZrO_2$ ceramic than on both the raw and polished $LS_2$. Evaluating various surface topographies of $LS_2$ showed that increasing surface roughness improved cell adhesion, leading to an increase of up to 13%. Conclusions: Our results demonstrate that a biomaterial, here $LS_2$, can be modified using simple surface changes in order to finely modulate soft tissue adhesion. Strong adhesion at the abutment associated with weak migration assists in gingival wound healing. On the same material, polishing can reduce cell adhesion without drastically modifying cell migration. A comparison of $LS_2$ and $ZrO_2$ ceramic showed that $LS_2$ was more conducive to creating varying tissue reactions. Our results can help dental surgeons to choose, especially for esthetic implant abutments, the most appropriate biomaterial as well as the most appropriate surface treatment to use in accordance with specific clinical dental applications.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.2.1-2.9
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• 2015

Background: The aim of this study was to evaluate the effect of autogenous tooth bone as a graft material for regeneration of bone in vertical bony defects of the minipigs. Material and Methods: Six minipigs were used in this study. Four molars were extracted in the right mandibular dentition and sent to the Korea Tooth Bank for fabrication of autogenous tooth bone. Ten days later, each extraction site was implanted with MS Implant Narrow Ridge $3.0{\times}10mm$ fixture (Osstem, Seoul, Korea) after standardized 2mm-sized artificial vertical bony defect formation. Pineappleshaped Root-On type autogenous tooth bones were applied to the vertical defects around the neck area of the posterior three fixtures and the fore-most one was not applied with autogenous bone as a control group. Each minipig was sacrificed at 4, 8, 12 weeks after fixture installation and examined radiologically and histologically. Histological evaluation was done under light microscope with Villanueva osteochrome bone staining with semi-quantitative histomorphometric study. Percentage of new bone over total area (NBF) and bone to implant contact (BIC) ratio were evaluated using digital software for area calculation. Result: NBF were $48.15{\pm}18.02%$, $45.50{\pm}28.37%$, and $77.13{\pm}15.30%$ in 4, 8, and 12 weeks, respectively for experimental groups. The control group showed $37.00{\pm}11.53%$, $32.25{\pm}26.99%$, and $1.33{\pm}2.31%$ in 4,8,12 weeks, respectively. BIC ratio were $53.08{\pm}19.82%$, $45.00{\pm}28.37%$, and $75.13{\pm}16.55%$ in 4,8,12 weeks, respectively. Those for the control groups were $38.33{\pm}6.43%$, $33.50{\pm}29.51%$, and $1.33{\pm}2.31%$ in 4, 8, 12 weeks, respectively. Conclusion: Autogenous tooth bone showed higher score than control group in NBF and BIC in all the data encompassing 4,8,12 weeks specimens, but statistically significant only 12 weeks data in both NBF and BIC.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.337-349
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• 2008

Despite an improved bone reactions of Mg-incorporated implants in the animals, little yet has been carried out by the experimental investigations in functional loading conditions. This study investigated the clinical and histologic parameters of osseointegrated Mg-incorporated implants in delayed loading conditions. A total of 36 solid screw implants (diameter 3.75 mm, length 10mm) were placed in the mandibles of 6 beagle dogs. Test groups included 18 Mg-incorporated implants. Turned titanium Implants served as control. Gold crowns were inserted 3 months. Radiographic assessments and stabilitytests were performed at the time of fixture installation, $2^{nd}$ stage surgery, 1 and 3 months after loading. Histological observations and morphometrical measurements were also performed. Of 36 implants, 32 displayed no discernible mobility, corresponding to successful clinical function. There was no statistically significant difference between test implants and controls in marginal bone levels (p=0.413) and RFA values. The mean BIC % in the Mg-implants was $54.4{\pm}20.2%$. The mean BIC % in the turned implant was $48.9{\pm}8.0%$. These differences between the Mg-implant and control implant were not statistically significant (P=0.264). In the limitation of this study, bone-to-implant contact (BIC) and bone area of Mg-incorporated oxidized implant were similar to machine-turned implant. The stability analysis showed no significantly different ISQ values and marginal bone loss between two groups. Considering time-dependent bone responses of Mg-implant, it seems that Mg-implants enhanced bone responses in early loading conditions and osseointegrated similarly to cp Ti implants in delayed loading conditions. However, further investigations are necessary to obtain long-term bone response of the Mg-implant in human.