Publications by authors named "Jae Kook Cha"

74 Publications

Programmed BMP-2 release from biphasic calcium phosphates for optimal bone regeneration.

Biomaterials 2021 Mar 29;272:120785. Epub 2021 Mar 29.

Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, 03722, Republic of Korea. Electronic address:

This study aimed to fabricate a multi-layered biphasic calcium phosphate (BCP) platform for programmed bone morphogenetic protein-2 (BMP-2) release, which means to block the initial burst release and promote releasing during the differentiation phase of osteogenic cells. And it is to confirm in vivo whether this platform has osteogenic inductivity even when extremely low doses of BMP-2 are loaded compared to the conventional soaking method. Our strategy consisted of preparing a multilayer coating on BCP to minimize the contact between BMP-2 and BCP and allow the loading of BMP-2. The multilayer, which is surface-modified on BCP, is composed of an organosilicate and a natural polymer-based layer-by-layer (LbL) film. We applied (3-Aminopropyl)triethoxysilane (APTES) as an organosilicate was used for amine-functionalized BCP and (collagen/heparin) film was used to delay and sustain BMP-2 release. The coated multilayer not only reduced the initial burst release by more than 50% but also loaded more BMP-2. For in vivo experiment, histomorphometric analysis, it was observed that the BCP platform loaded with extremely low concentration BMP-2 (0.01 mg/ml) induced a significantly larger amount of new bones at 8 weeks compared to the conventional soaking method in the rabbit calvarium onlay graft model.
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http://dx.doi.org/10.1016/j.biomaterials.2021.120785DOI Listing
March 2021

Scanning Electron Microscopic Evaluation of the Internal Fit Accuracy of 3D-Printed Biphasic Calcium Phosphate Block: An Ex Vivo Pilot Study.

Materials (Basel) 2021 Mar 22;14(6). Epub 2021 Mar 22.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul 03722, Korea.

The aim of this study was to assess the internal fit accuracy of a three-dimensional (3D)-printed biphasic calcium phosphate (BCP) block compared with a 3D-milled poly methyl methacrylate (PMMA) block by scanning electron microscope (SEM) analysis. In a total of 20 porcine rib bones, two different types of defects having two adjacent walls and a floor were produced: a defect with a flat floor (flat defect; = 10) and a defect with a concave floor (curved defect; = 10). Each defect was grafted with either the 3D-printed BCP block or the 3D-milled PMMA block fabricated following the computer aided design. The defects were then cut cross-sectionally and evaluated under the SEM. The extents of internal contact and gap were measured and statistically analyzed ( < 0.05). All blocks in both BCP and PMMA groups were successfully fit to the flat and curved defects. The internal contact ratio was significantly higher in the BCP group (flat defect: 0.47 ± 0.10; curved defect: 0.29 ± 0.05) compared with the PMMA group (flat defect: 0.21 ± 0.13; curved defect: 0.17 ± 0.04; < 0.05). The internal gap area was similar between the two groups regardless of the defect types ( > 0.05). The internal fit accuracy of the 3D-printed BCP block was reliable in both the flat and curved defects when compared with the accuracy of the 3D-milled PMMA block.
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http://dx.doi.org/10.3390/ma14061557DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8004813PMC
March 2021

Diverse patterns of bone regeneration in rabbit calvarial defects depending on the type of collagen membrane.

J Periodontal Implant Sci 2021 Feb;51(1):40-52

Department of Periodontology, Research Institute of Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: Various crosslinking methods have been introduced to increase the longevity of collagen membranes. The aim of this study was to compare and evaluate the degradation and bone regeneration patterns of 3 collagen membranes.

Methods: Four 8-mm-diameter circular bone defects were created in the calvaria of 10 rabbits. In each rabbit, each defect was randomly allocated to 1) the sham control group, 2) the non-crosslinked collagen sponge (NS) group, 3) the chemically crosslinked collagen membrane (CCM) group, or 4) the biphasic calcium phosphate (BCP)-supplemented ultraviolet (UV)-crosslinked collagen membrane (UVM) group. Each defect was covered with the allocated membrane without any graft material. Rabbits were sacrificed at either 2 or 8 weeks post-surgery, and radiographic and histologic analyses were done.

Results: New bone formed underneath the membrane in defects in the CCM and UVM groups, with a distinctive new bone formation pattern, while new bone formed from the base of the defect in the NS and control groups. The CCM maintained its shape until 8 weeks, while the UVM and NS were fully degraded at 8 weeks; simultaneously, sustained inflammatory infiltration was found in the margin of the CCM, while it was absent in the UVM. In conclusion, the CCM showed longer longevity than the UVM, but was accompanied by higher levels of inflammation.

Conclusions: Both the CCM and UVM showed distinctive patterns of enhancement in new bone formation in the early phase. UV crosslinking can be a biocompatible alternative to chemical crosslinking.
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http://dx.doi.org/10.5051/jpis.2004180209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7920838PMC
February 2021

Immunohistochemical characteristics of lateral bone augmentation using different biomaterials around chronic peri-implant dehiscence defects: An experimental in vivo study.

Clin Oral Implants Res 2021 Feb 25. Epub 2021 Feb 25.

Department of Periodontology, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain.

Aim: To investigate the immunohistochemical characteristics of a highly porous synthetic bone substitute and a cross-linked collagen membrane for guided bone regeneration.

Methods: Three experimental groups were randomly allocated at chronic peri-implant dehiscence defect in 8 beagle dogs: (i) biphasic calcium phosphate covered by a cross-linked collagen membrane (test group), (ii) deproteinized bovine bone mineral covered by a natural collagen membrane (positive control) and (iii) no treatment (negative control). After 8 and 16 weeks of submerged healing, dissected tissue blocks were processed for immunohistochemical analysis. Seven antibodies were used to detect the remaining osteogenic and angiogenic potential, and quantitative immunohistochemical analysis was done by software.

Results: The antigen reactivity of alkaline phosphatase was significantly higher in the test group compared to the positive and negative controls, and it maintained till 16 weeks. The intensity of osteocalcin was significantly higher in the positive control at 8 weeks than the other groups, but significantly decreased at 16 weeks and no difference was found between the groups. A significant large number of TRAP-positive cells were observed in the test group mainly around the remaining particles at 16 weeks. The angiogenic potential was comparable between the groups showing no difference in the expression of transglutaminase II and vascular endothelial growth factor.

Conclusion: Guided bone regeneration combining a highly porous biphasic calcium phosphate synthetic biomaterial with a crosslinked collagen membrane, resulted in extended osteogenic potential when compared to the combination of deproteinized bovine bone mineral and a native collagen membrane.
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http://dx.doi.org/10.1111/clr.13726DOI Listing
February 2021

Evaluation of success rate and biomechanical stability of ultraviolet-photofunctionalized miniscrews with short lengths.

Am J Orthod Dentofacial Orthop 2021 Feb 24;159(2):158-166. Epub 2020 Nov 24.

Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, South Korea. Electronic address:

Introduction: The aim of this research was to verify that ultraviolet light (UV)-photofunctionalization improves the success rate and biomechanical stability of miniscrews regardless of length, and to evaluate the comparability of biomechanical stability between UV-photofunctionalized miniscrews with short lengths and untreated miniscrews with conventional lengths.

Methods: Eight male beagles (age, 12-15 months; weight, 10-13 kg) received a total of 64 miniscrews, including 7-mm and 4-mm untreated and UV-photofunctionalized, acid-etched miniscrews with the use of a random block design. The cumulative success rates were examined in all studied groups. The insertion and removal torques and screw mobility were measured. Microcomputed tomographic scans and histomorphometric analyses were performed at 8 weeks postoperatively.

Results: The success rates of 7-mm UV-untreated and UV-photofunctionalized miniscrews were 87.5% and 100%, respectively, vs 43.8% for the 4-mm UV-untreated and 4-mm UV-photofunctionalized miniscrews. The rates were significantly different in accordance with the length (P <0.001). There were no differences in the insertion and removal torque and screw mobility between groups according to the length or UV treatment. However, the 4-mm UV-untreated miniscrews yielded a mean bone area ratio of 6.35 ± 7.43%, whereas the 7-mm UV-photofunctionalized miniscrew yielded a mean ratio of 32.17 ± 8.34% (P = 0.037).

Conclusions: The UV-photofunctionalization significantly increased the biomechanical stability and led to increased bone and miniscrew contact area in dogs with miniscrews of the same length. However, the most important factor that affected the success rate of the miniscrew was the length.
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http://dx.doi.org/10.1016/j.ajodo.2019.12.018DOI Listing
February 2021

Clinical and Microbiological Efficacy of Pyrophosphate Containing Toothpaste: A Double-Blinded Placebo-Controlled Randomized Clinical Trial.

Microorganisms 2020 Nov 17;8(11). Epub 2020 Nov 17.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea.

(1) Background: Dental calculus works as a niche wherein pathogenic bacteria proliferate in the oral cavity. Previous studies revealed the anticalculus activity of pyrophosphates, however there was no clinical study that evaluated microbiome changes associated with calculus inhibition. Therefore, the aim of this randomized clinical trial was to evaluate the calculus inhibition of pyrophosphate-containing toothpaste and its effect on oral microbiome changes. (2) Methods: Eighty subjects with a calculus index ≥2 on the lingual of the mandibular anterior tooth were randomly allocated to the test group that pyrophosphate-containing toothpaste was given to or the placebo control group. Full mouth debridement and standardized tooth brushing instruction were given before the allocation. Plaque index, gingival index, calculus index, probing depth, and bleeding on probing were measured at the baseline, and at 4, 8 and 12 weeks. Genomic DNA was extracted from the plaque samples collected at the baseline and at 12 weeks, and 16S ribosomal RNA gene amplicon sequencing was applied for microbiome analysis. (3) Results: None of the clinical parameters showed significant differences by visits or groups, except the plaque index of the test group, which reduced significantly between 4 and 12 weeks. A significant difference of microbiome between the baseline and 12 weeks was observed in the test group. Between baseline and 12 weeks, the proportion of decreased in the control group, and the proportions of , and in the phylum level and the proportions of , and in the genus level decreased in the test group. In the test group, as plaque index decreased, increased, and and decreased. (4) Conclusion: The use of pyrophosphate-containing toothpaste effectively inhibited the dysbiosis of the oral microbiome and the proliferation of pathogenic species in periodontal disease. Clinically, plaque formation in the pyrophosphate-containing toothpaste group was effectively decreased, however there was no significant change in calculus deposition.
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http://dx.doi.org/10.3390/microorganisms8111806DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7698517PMC
November 2020

Significance of implant design on the efficacy of different peri-implantitis decontamination protocols.

Clin Oral Investig 2020 Nov 10. Epub 2020 Nov 10.

Section of graduate Periodontology, Faculty of Odontology, Complutense University of Madrid, Madrid, Spain.

Objective: To assess the efficacy of three mechanical decontamination methods in four types of commercially available implants.

Material And Methods: Ninety-six implants of four commercial brands with different designs (regarding thread depth and thread pitch) were soaked in a surrogate biofilm (ink) and air-dried. Circumferential standardized peri-implant defects with 6 mm in depth and 1.55 mm in width were custom-made with a 3D printer. Stained implants were inserted in the defects and instrumented with three different methods: a titanium brush (TNB), a metallic ultrasonic tip (IST) and an air abrasive (PF). Standardized photographs were taken vertically to the implant axis (flat view), and with angulations of 60° (upper view) and 120° (lower view) to the implant long axis. The percentage of residual stain (PRS) was calculated with the image analysis software. Scanning electron microscope evaluations were performed on the buccal aspect of the implants at the central level of the defect.

Results: The efficacy of PF was significantly inferior to the TNB and IST in all implant designs, while there were no significant differences between TNB and IST. IST showed significantly higher PRS in the implant with the highest thread pitch, while the TNB had the highest PRS in the implant with a marked reverse buttress-thread design. The micro-thread design had the lowest values of PRS for all decontamination methods. The apically facing threads represented the areas with highest PRS for all implant designs and decontamination methods.

Conclusion: Thread geometry influenced the access of the decontamination devices and in turn its efficacy. Implants with lower thread pitch and thread depth values appeared to have less residual staining.

Clinical Relevance: Clinicians must be aware of the importance of thread geometry in the decontamination efficacy.
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http://dx.doi.org/10.1007/s00784-020-03681-yDOI Listing
November 2020

Transcriptomic profiles and their correlations in saliva and gingival tissue biopsy samples from periodontitis and healthy patients.

J Periodontal Implant Sci 2020 Oct;50(5):313-326

Department of Periodontology, Research Institute of Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: This study was conducted to analyze specific RNA expression profiles in gingival tissue and saliva samples in periodontitis patients and healthy individuals, and to determine their correlations in light of the potential use of microarray-based analyses of saliva samples as a periodontal monitoring tool.

Methods: Gingival tissue biopsies and saliva samples from 22 patients (12 with severe periodontitis and 10 with a healthy periodontium) were analyzed using transcriptomic microarray analysis. Differential gene expression was assessed, and pathway and clustering analyses were conducted for the samples. The correlations between the results for the gingival tissue and saliva samples were analyzed at both the gene and pathway levels.

Results: There were 621 differentially expressed genes (DEGs; 320 upregulated and 301 downregulated) in the gingival tissue samples of the periodontitis group, and 154 DEGs (44 upregulated and 110 downregulated) in the saliva samples. Nine of these genes overlapped between the sample types. The periodontitis patients formed a distinct cluster group based on gene expression profiles for both the tissue and saliva samples. Database for Annotation, Visualization and Integrated Discovery analysis revealed 159 enriched pathways from the tissue samples of the periodontitis patients, as well as 110 enriched pathways In the saliva samples. Thirty-four pathways overlapped between the sample types.

Conclusions: The present results indicate the possibility of using the salivary transcriptome to distinguish periodontitis patients from healthy individuals. Further work is required to enhance the extraction of available RNA from saliva samples.
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http://dx.doi.org/10.5051/jpis.1905460273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606893PMC
October 2020

Efficacy of Local Minocycline Agents in Treating Peri-Implantitis: An Experimental In Vivo Study in Beagle Dogs.

Pharmaceutics 2020 Oct 23;12(11). Epub 2020 Oct 23.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul 03772, Korea.

Background: Local delivery agents (LDA) have the advantage of delivering the antibiotics at high concentrations to the targeted sites. However, the constant flow of gingival crevicular fluids and saliva may restrict their efficacy. Therefore, the drug sustainability and pharmacodynamic properties of any proposed LDA should be evaluated.

Methods: Four dental implants were placed unilaterally in the edentulous mandible of six beagle dogs. Peri-implantitis were experimentally induced using silk-ligatures. Each implant was randomly allocated to receive one of the following four treatments: (i) MC (Chitosan-alginate (CA) minocycline), (ii) MP (CA-without minocycline), (iii) PG (Polyacrylate-glycerin minocycline), and (iv) Control (mechanical debridement only). Mechanical therapies and LDAs were administered into the gingival sulcus two times at a 4-week interval. Drug sustainability as well as clinical, radiographical, and immunohistochemical (IHC) analyses were conducted to evaluate the efficacies of treatments.

Results: Reduced mean probing depth was observed in all of the test groups after the second delivery. A minimal marginal bone level change was observed during the treatment period (MP (-0.06 ± 0.53 mm) to PG (-0.25 ± 0.42 mm)). The distribution of IHC cell marker analysis of all targeted antibodies ranged from 6.34% to 11.33%. All treatment outcomes between the test groups were comparable. A prolonged retention of LDA was observed from CA microspheres (MC and MP) at both administrations ( < 0.017) and prolonged sustainability of bacteriostatic effect was observed from MC compared to PG after the second administration ( < 0.05).

Conclusions: Prolonged retention of CA microspheres was observed and the longer bacteriostatic effect was observed from the MC group. Mechanical debridement with adjunct LDA therapy may impede peri-implantitis progression, however, prolonged drug action did not lead to improved treatment outcome.
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http://dx.doi.org/10.3390/pharmaceutics12111016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7690844PMC
October 2020

Core Ossification of Bone Morphogenetic Protein-2-Loaded Collagenated Bone Mineral in the Sinus.

Tissue Eng Part A 2020 Oct 19. Epub 2020 Oct 19.

Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.

The objective of this study was to investigate release kinetics and ossification patterns of bone morphogenetic protein-2-soaked collagenated porcine bone mineral (BMP-2/CPBM) in rabbit sinuses. Release kinetics of BMP-2/CPBM was determined up to 56 days. In 16 rabbits, BMP-2/CPBM (BMP group) and CPBM alone (control group) were bilaterally grafted in both sinuses. After 4 ( = 8) and 12 ( = 8) weeks, radiographic and histologic analyses were performed. Approximately 40% of BMP-2 was released from CPBM during 3 days ; release maintained at a reduced level until day 56. , new bone formation in BMP group was dominant at the center and decreased toward the borders of the sinus, while it mainly possessed close to the sinus membrane and basal bone in control group. At the center, significantly more new bone was found in BMP group compared to control group at 4 weeks (29.14% vs. 16.50%;  < 0.05). The total augmented volume of BMP group was significantly greater than control group at 4 (370.13 mm vs. 299.32 mm) and 12 (400.40 mm vs. 290.10 mm) weeks ( < 0.05). In conclusion, BMP-2/CPBM demonstrated a core ossification with a greater augmented volume and new bone formation in the center of the sinus compared to CPBM alone. Impact statement The center of the augmented maxillary sinus tends to show a slower and inferior new bone formation compared to the sites near the sinus membrane and basal bone. In this study, bone morphogenetic protein-2 (BMP-2) loaded onto collagenated porcine bone mineral (CPBM) resulted in a greater augmented volume and new bone formation at the center of the grafted sinus compared to CPBM alone. Therefore, BMP-2-added CPBM in maxillary sinus augmentation may potentially be beneficial to the clinicians, in terms of accelerating the new bone formation at the center area where the apical half of the implant fixture usually places.
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http://dx.doi.org/10.1089/ten.TEA.2020.0151DOI Listing
October 2020

Dimensional changes of the maxillary sinus augmented with a collagenated synthetic bone block or synthetic bone particulates: A pre-clinical study in rabbits.

J Clin Periodontol 2020 11 21;47(11):1416-1426. Epub 2020 Sep 21.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, South Korea.

Objective: To compare the efficacy of a collagenated synthetic bone substitute (C-SBS) to a particulated synthetic bone substitute (P-SBS) in volume maintenance and new bone formations in a rabbit sinus model.

Materials And Methods: Either C-SBS or P-SBS was grafted in both sinuses of 16 rabbits. Four (N = 8) or 12 (N = 8) weeks after the surgery, total augmented volume (TAV) and area (TAA), as well as new bone volume (NBV) and area (NBA), were statistically compared by radiographic and histomorphometric analyses (p < .05).

Results: The differences in TAV, NBV, TAA and NBA between C-SBS and P-SBS groups at 4 weeks were not statistically significant. The TAV (267.13 ± 62.08 vs. 200.18 ± 40.32 mm ) and NBV (103.26 ± 10.50 vs. 71.10 ± 7.58 mm ) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < .05). The TAA (19.36 ± 2.88 vs. 14.48 ± 2.08 mm ) and NBA (5.43 ± 1.20 vs. 3.76 ± 0.78 mm ) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < .05).

Conclusions: Collagenated synthetic bone substitute grafted in rabbit sinuses demonstrated more favourable outcomes across all outcome measures compared to P-SBS at 12 weeks.
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http://dx.doi.org/10.1111/jcpe.13363DOI Listing
November 2020

Soft Tissue Dimensions Following Tooth Extraction in the Posterior Maxilla: A Randomized Clinical Trial Comparing Alveolar Ridge Preservation to Spontaneous Healing.

J Clin Med 2020 Aug 10;9(8). Epub 2020 Aug 10.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul 03722, Korea.

Background: To assess the soft tissue dimension following tooth extraction and alveolar ridge preservation in the posterior maxilla compared to spontaneous healing.

Methods: Thirty-five patients randomly assigned to alveolar ridge preservation (ARP) and spontaneous healing (SH) after maxillary molar extraction. The crestal, buccal, and palatal gingival thickness at 6 months was measured around virtually placed implant fixtures using superimposed cone-beam computed tomography and intraoral scan taken at 6 months. Buccal mucogingival junction (MGJ) level change over 6 months was estimated using intraoral scans obtained at suture-removal and 6 months.

Results: The crestal gingiva was significantly thinner in group ARP (-1.16 mm) compared to group SH ( < 0.05). The buccal and palatal gingiva was significantly thinner at the implant shoulder (IS) level in group ARP (buccal: -0.75 mm; palatal: -0.85 mm) compared to group SH ( < 0.05). The thickness at 2 mm below the IS of both sides and the buccal MGJ level change were similar in both groups ( > 0.05).

Conclusions: ARP in the posterior maxilla resulted in a thinner soft tissue on top of and at the prospective level of the implant shoulder at 6 months. The buccal MGJ level changed minimal for 6 months in both groups.
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http://dx.doi.org/10.3390/jcm9082583DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7464084PMC
August 2020

Locally Applied Slow-Release of Minocycline Microspheres in the Treatment of Peri-Implant Mucositis: An Experimental In Vivo Study.

Pharmaceutics 2020 Jul 16;12(7). Epub 2020 Jul 16.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul 03772, Korea.

Background: The objective of this is preclinical investigation was to evaluate the differential drug sustainability and pharmacodynamic properties of two local minocycline microsphere carriers: chitosan-coated alginate (CA) and poly(meth)acrylate-glycerin (PG).

Methods: Four dental implants were placed unilaterally in the edentulous mandible of six beagle dogs. Each implant was randomly assigned to receive one of the following four treatments: (i) CA (CA-based minocycline), (ii) placebo (CA substrate without minocycline), (iii) PG (PG-based minocycline) and (iv) control (mechanical debridement only). After inducing peri-implant mucositis, the randomly assigned treatments were administered into the gingival sulcus twice at a 4-week interval using a plastic-tipped syringe. Drug sustainability and pharmacodynamic (clinical, radiographical and cell marker intensity) evaluations were performed after each administration.

Results: The CA microspheres remained longer around the healing abutment compared to the PG microspheres at both administrations and a longer bacteriostatic effect was observed from CA (7.0 ± 5.7 days) compared to PG (1.2 ± 2.6 days). The efficacy of the applied therapies based on clinical, radiographical and histological analyses were comparable across all treatment groups.

Conclusions: CA microspheres showed longer carrier and bacteriostatic effect sustainability when compared to PG microspheres, however, longer drug sustainability did not lead to improved treatment outcomes.
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http://dx.doi.org/10.3390/pharmaceutics12070668DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7407908PMC
July 2020

Effects of soft tissue grafting prior to orthodontic treatment on preventing gingival recession in dogs.

J Periodontal Implant Sci 2020 Aug 12;50(4):226-237. Epub 2020 May 12.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: This study was conducted to assess the efficacy of prophylactic gingival grafting in the mandibular anterior labial area for preventing orthodontically induced gingival recession.

Methods: Eight mongrel dogs received gingival graft surgery at the first (I1) and third (I3) mandibular incisors on both sides based on the following group allocation: AT group (autogenous connective tissue graft on I1), AT-control group (contralateral side in the AT group), CM group (xenogeneic cross-linked collagen matrix graft on I3) and CM-control group (contralateral side in the CM group). At 4 weeks after surgery, 6 incisors were splinted and proclined for 4 weeks, followed by 16 weeks of retention. At 24 weeks after surgery, casts were made and compared with those made before surgery, and radiographic and histomorphometric analyses were performed.

Results: Despite the proclination of the incisal tip (by approximately 3 mm), labial gingival recession did not occur. The labial gingiva was thicker in the AT group (1.85±0.50 mm vs. 1.76±0.45 mm, >0.05) and CM group (1.90±0.33 mm vs. 1.79±0.20 mm, >0.05) than in their respective control groups.

Conclusions: The level of the labial gingival margin did not change following labial proclination of incisors in dogs. Both the AT and CM groups showed enhanced gingival thickness.
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http://dx.doi.org/10.5051/jpis.2000420021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7443382PMC
August 2020

Oral Fluid Biomarkers for Diagnosing Gingivitis in Human: A Cross-Sectional Study.

J Clin Med 2020 Jun 3;9(6). Epub 2020 Jun 3.

Department of Periodontology, Research Institute of Periodontal Regeneration, Yonsei University College of Dentistry, Seoul 120-749, Korea.

Diagnoses based on oral fluid biomarkers have been introduced to overcome limitations of periodontal probe-based diagnoses. Diagnostic ability of certain biomarkers for periodontitis have been identified and widely studied, however, such studies targeting gingivitis is scarce. The aims of this study were to determine and compare the efficacies and accuracies of eight biomarkers in diagnosing gingivitis with the aid of receiver operating characteristic (ROC) curves. The probing depth (PD), clinical attachment loss (CAL), bleeding on probing (BOP), gingival index (GI), and plaque index (PI) were examined in 100 participants. Gingival crevicular fluid was collected using paper points, and whole-saliva samples were collected using cotton roll. Samples were analyzed using enzyme-linked immunosorbent assay kits for the different biomarkers. The levels of matrix metalloproteinase (MMP)-8, MMP-9, lactoferrin, cystatin C, myeloperoxidase (MPO), platelet-activating factor, cathepsin B, and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen were analyzed. MPO and MMP-8 levels in saliva were strongly correlated with gingivitis, with Pearson's correlation coefficients of 0.399 and 0.217, respectively. The area under the curve (AUC) was largest for MMP-8, at 0.814, followed by values of 0.793 and 0.777 for MPO and MMP-9, respectively. The clinical parameters of GI and PI showed strong correlations and large AUC values, whereas PD and CAL did not. MMP-8 and MPO were found to be effective for diagnosing gingivitis. Further investigations based on the results of this study may identify clinically useful biomarkers for the accurate and early detection of gingivitis.
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http://dx.doi.org/10.3390/jcm9061720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356847PMC
June 2020

Immediate versus delayed application of bone morphogenetic protein-2 solution in damaged extraction sockets: a preclinical in vivo investigation.

Clin Oral Investig 2021 Jan 26;25(1):275-282. Epub 2020 May 26.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, 03722, South Korea.

Objective: To compare the clinical, radiographic, and histological healing patterns between the immediate and delayed applications of bone morphogenetic protein-2 (BMP-2) in damaged extraction sockets in dogs.

Materials And Methods: The distal roots of the fourth premolars of the mandible were extracted bilaterally in five beagle dogs, and buccal bone defects (4 mm wide and 9 mm high) were surgically created. Collagenated biphasic calcium phosphate (CBCP) soaked for 10 min in 100 μL of BMP-2 solution was applied immediately to the defect site in the control group. In the test group, the BMP-2 solution of same dose was injected into the grafted site 2 weeks after grafting with a saline-soaked CBCP. The dogs were sacrificed 2 weeks later. Clinical, histological, and radiographic analyses were followed.

Results: Swelling and inflammatory reactions were predominantly observed in the control group at 2 weeks. The area of new bone formation was significantly larger in the control group compared with the test group (10.8 ± 7.0 mm [mean ± SD] and 6.3 ± 3.1 mm, respectively; p = 0.043). No significant difference was found in ridge width at 2 mm, 4 mm and 6 mm below the lingual bone crest between the control (2.6 ± 1.0 mm, 3.2 ± 0.9 mm and 4.5 ± 0.5 mm, respectively) and test group (3.3 ± 1.0 mm, 3.7 ± 1.3 mm and 4.2 ± 1.0 mm; all p > 0.05).

Conclusions: Delayed application of BMP-2 2 weeks after surgery did not show any advantage over immediate application of BMP-2 in terms of new bone formation.

Clinical Relevance: This study suggests that it might be better to apply BMP-2 immediately in alveolar ridge preservation, instead of delayed application, in order to enhance new bone formation.
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http://dx.doi.org/10.1007/s00784-020-03362-wDOI Listing
January 2021

Distinctive bone regeneration of calvarial defects using biphasic calcium phosphate supplemented ultraviolet-crosslinked collagen membrane.

J Periodontal Implant Sci 2020 Feb 19;50(1):14-27. Epub 2019 Dec 19.

Department of Periodontology, Research Institute of Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: To overcome several drawbacks of chemically-crosslinked collagen membranes, modification processes such as ultraviolet (UV) crosslinking and the addition of biphasic calcium phosphate (BCP) to collagen membranes have been introduced. This study evaluated the efficacy and biocompatibility of BCP-supplemented UV-crosslinked collagen membrane for guided bone regeneration (GBR) in a rabbit calvarial model.

Methods: Four circular bone defects (diameter, 8 mm) were created in the calvarium of 10 rabbits. Each defect was randomly allocated to one of the following groups: 1) the sham control group (spontaneous healing); 2) the M group (defect coverage with a BCP-supplemented UV-crosslinked collagen membrane and no graft material); 3) the BG (defects filled with BCP particles without membrane coverage); and 4) the BG+M group (defects filled with BCP particles and covered with a BCP-supplemented UV-crosslinked collagen membrane in a conventional GBR procedure). At 2 and 8 weeks, rabbits were sacrificed, and experimental defects were investigated histologically and by micro-computed tomography (micro-CT).

Results: In both micro-CT and histometric analyses, the BG and BG+M groups at both 2 and 8 weeks showed significantly higher new bone formation than the control group. On micro-CT, the new bone volume of the BG+M group (48.39±5.47 mm) was larger than that of the BG group (38.71±2.24 mm, =0.032) at 8 weeks. Histologically, greater new bone area was observed in the BG+M group than in the BG or M groups. BCP-supplemented UV-crosslinked collagen membrane did not cause an abnormal cellular reaction and was stable until 8 weeks.

Conclusions: Enhanced new bone formation in GBR can be achieved by simultaneously using bone graft material and a BCP-supplemented UV-crosslinked collagen membrane, which showed high biocompatibility and resistance to degradation, making it a biocompatible alternative to chemically-crosslinked collagen membranes.
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http://dx.doi.org/10.5051/jpis.2020.50.1.14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040443PMC
February 2020

Volume stability of the augmented sinus using a collagenated bovine bone mineral grafted in case of a perforated Schneiderian membrane: An experimental study in rabbits.

J Clin Periodontol 2020 05 11;47(5):649-656. Epub 2020 Mar 11.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Objectives: To determine the volume stability of a sinus augmented with a collagenated bovine bone mineral (CBBM) in case of an intact or perforated Schneiderian membrane (SM).

Materials And Methods: A bilateral sinus augmentation procedure was performed in eight rabbits. The SM was intentionally perforated in one side (SMP group), while it remained intact in contra-lateral side (control group) and the same amount of CBBM was then grafted. At 12 weeks, the animals were euthanized for radiographic and histomorphometric analyses.

Results: The augmented volume did not differ significantly between the two groups: 262.2 ± 32.1 mm in SMP group and 261.9 ± 48.5 mm in the control group (p = .959). There was no significant difference in the total augmented area: 24.7 ± 5.2 mm in SMP group and 23.2 ± 2.9 mm in the control group (p = .773). The areas of newly formed bone also did not differ significantly between the two groups, but was significantly lower at the centre of the augmented region than in the region of the surgical window in both groups (p < .05).

Conclusion: A perforation of the SM in a rabbit model does neither impact the augmented volume nor new bone formation following grafting of the sinus with a CBBM.
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http://dx.doi.org/10.1111/jcpe.13273DOI Listing
May 2020

Bioactive characteristics of an implant surface coated with a pH buffering agent: an study.

J Periodontal Implant Sci 2019 Dec 4;49(6):366-381. Epub 2019 Nov 4.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: The purpose of this study was to evaluate the effectiveness of conventional sandblasted, large-grit, acid-etched (SLA) surface coated with a pH buffering solution based on surface wettability, blood protein adhesion, osteoblast affinity, and platelet adhesion and activation.

Methods: Titanium discs and implants with conventional SLA surface (SA), SLA surface in an aqueous calcium chloride solution (CA), and SLA surface with a pH buffering agent (SOI) were prepared. The wetting velocity was measured by the number of threads wetted by blood over an interval of time. Serum albumin adsorption was tested using the bicinchoninic acid assay and by measuring fluorescence intensity. Osteoblast activity assays (osteoblast adhesion, proliferation, differentiation, mineralization, and migration) were also performed, and platelet adhesion and activation assays were conducted.

Results: In both the wetting velocity test and the serum albumin adsorption assay, the SOI surface displayed a significantly higher wetting velocity than the SA surface (=0.000 and =0.000, respectively). In the osteoblast adhesion, proliferation, differentiation, and mineralization tests, the mean values for SOI were all higher than those for SA and CA. On the osteoblast migration, platelet adhesion, and activation tests, SOI also showed significantly higher values than SA (=0.040, =0.000, and =0.000, respectively).

Conclusions: SOI exhibited higher hydrophilicity and affinity for proteins, cells, and platelets than SA. Within the limits of this study, it may be concluded that coating an implant with a pH buffering agent can induce the attachment of platelets, proteins, and cells to the implant surface. Further studies should be conducted to directly compare SOI with other conventional surfaces with regard to its safety and effectiveness in clinical settings.
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http://dx.doi.org/10.5051/jpis.2019.49.6.366DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6920039PMC
December 2019

Lateral onlay grafting using different combinations of soft-type synthetic block grafts and resorbable collagen membranes: An experimental in vivo study.

Clin Oral Implants Res 2020 Apr 3;31(4):303-314. Epub 2020 Jan 3.

Clinic of Reconstructive Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.

Objectives: To observe the sequential healing of lateral onlay grafts in terms of volumetric and histological changes when using different combinations of synthetic soft-type block bone and resorbable collagen membranes.

Materials And Methods: A lateral onlay graft procedure was applied at the chronic narrow alveolar ridge of the mandible in 15 beagle dogs. The groups were allocated as follows: (a) empty control; (b) onlay graft using soft-type block bone 1 (hydroxyapatite [HA]: β-tricalcium phosphate [β-TCP] = 15:85) and a non-cross-linked collagen membrane (MP-BG group); (c) onlay graft using soft-type block bone 2 (HA:β-TCP = 60:40) and a non-cross-linked collagen membrane (OC-BG group); and (d) onlay graft using soft-type block bone 1 (HA:β-TCP = 15:85) and a cross-linked collagen membrane (MP-CM group). Volumetric and histomorphometric analyses were performed at 4, 8 and 16 weeks postoperatively.

Results: No clinical complications occurred in any of the groups. The OC-BG group showed significantly larger total augmented volumes than the control and MP-BG groups after 8 and 16 weeks. The areas of new bone were significantly larger in the OC-BG group than the other groups at 16 weeks. The horizontal thickness of the augmented ridge was significantly larger in the OC-BG group than in the control group at 16 weeks.

Conclusion: The OC-BG group showed superior volume maintenance and osteogenic potential for up to 16 weeks compared to the other groups in an onlay graft model of the dog mandible despite the displacement of the bone graft.
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http://dx.doi.org/10.1111/clr.13566DOI Listing
April 2020

Clinical benefits of ridge preservation for implant placement compared to natural healing in maxillary teeth: A retrospective study.

J Clin Periodontol 2020 03 7;47(3):382-391. Epub 2020 Jan 7.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, South Korea.

Aim: The purpose of this retrospective study was to determine clinical benefits of ridge preservation in terms of surgical invasiveness of implant placement compared to natural healing in the maxilla.

Materials & Methods: This study included 178 patients with 206 implants placed at ridge-preserved sites and 493 patients with 656 implants placed at naturally healed sites in maxillary anterior and posterior regions. Patient- and implant-related data were collected from electronic dental records including additional augmentation procedures performed before or during implant placement and surgical complications. Cumulative survival rate was assessed using Kaplan-Meier method. The annual peri-implant marginal bone loss between the two groups was compared using the Mann-Whitney U test.

Results: The follow-up period was 24.4 ± 18.1 months (mean ± standard deviation) for ridge-preserved sites and 45.7 ± 29.6 months for naturally healed sites. Sinus augmentation was performed at similar frequencies in the two groups, but lateral approach was applied significantly more at naturally healed sites (37.2%) than ridge-preserved sites (8.3%, p ≤ .001). There was no intergroup difference in the cumulative survival rate or annual peri-implant marginal bone loss.

Conclusion: Ridge preservation can be clinically beneficial for minimizing the invasiveness of implant surgery by simplifying the procedure when sinus augmentation is expected in the maxilla.
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http://dx.doi.org/10.1111/jcpe.13231DOI Listing
March 2020

Histologic analysis following grafting of damaged extraction sockets using deproteinized bovine or porcine bone mineral: A randomized clinical trial.

Clin Oral Implants Res 2020 Jan 27;31(1):93-102. Epub 2019 Nov 27.

Department of Periodontology, Research Institute for Periodontal regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Objectives: This study histologically analyzed biopsy samples obtained from sites of damaged extraction socket grafting using deproteinized bovine bone mineral (DBBM) or deproteinized porcine bone mineral (DPBM) with coverage by a collagen membrane.

Material And Methods: One hundred patients participated in this randomized controlled clinical trial of extraction socket grafts performed in cases of periodontally compromised teeth. All participants were blinded to their group allocations, and each material was grafted with coverage by collagen membranes after extraction of the tooth and removal of granulation tissue. At implant placement at 4 months, a biopsy was harvested at the implant site using a trephine was analyzed histologically.

Results: Eighty-five biopsy samples were acquired, of which 81 were finally included in the histologic analysis (42 in DBBM and 39 in DPBM group). Both DBBM and DPBM groups showed comparable proportions of residual biomaterial (12.37 ± 5.67% and 12.21 ± 5.75%, respectively), newly formed bone (15.07 ± 10.52% and 18.47 ± 11.47%, respectively), and nonmineralized tissue (72.56 ± 10.07% and 71.55 ± 15.47%, respectively). There were no significant differences in these histologic parameters between the two groups with different biomaterials.

Conclusion: Comparable histologic bone formation was found in both socket grafted groups with DBBM or DPBM covered by collagen membranes in periodontally damaged extraction sockets. However, a wide variation in new bone formation was found after 4 months of postsurgical healing and a tendency of higher new bone formation was shown at damaged sockets that had an intact unilateral residual wall regardless of buccal or lingual side.
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http://dx.doi.org/10.1111/clr.13557DOI Listing
January 2020

Periodontal healing using a collagen matrix with periodontal ligament progenitor cells in a dehiscence defect model in beagle dogs.

J Periodontal Implant Sci 2019 Aug 16;49(4):215-227. Epub 2019 Jul 16.

Department of Periodontology, Research Institute of Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: To histologically characterize periodontal healing at 8 weeks in surgically created dehiscence defects in beagle dogs that received a collagen matrix with periodontal ligament (PDL) progenitor cells.

Methods: The bilateral maxillary premolars and first molars in 6 animals were used. Standardized experimental dehiscence defects were made on the buccal side of 3 premolars, and primary culturing of PDL progenitor cells was performed on the molars. Collagen matrix was used as a scaffold and a delivery system for PDL progenitor cells. The experimental sites were grafted with collagen matrix (COL), PDL progenitor cells with collagen matrix (COL/CELL), or left without any material (CTL). Histologic and histomorphometric analyses were performed after 8 weeks.

Results: The defect height from the cementoenamel junction to the most apical point of cementum removal did not significantly differ across the CTL, COL, and COL/CELL groups, at 4.57±0.28, 4.56±0.41, and 4.64±0.27 mm (mean ± standard deviation), respectively; the corresponding values for epithelial adhesion were 1.41±0.51, 0.85±0.29, and 0.30±0.41 mm (<0.05), the heights of new bone regeneration were 1.32±0.44, 1.65±0.52, and 1.93±0.61 mm (<0.05), and the cementum regeneration values were 1.15±0.42, 1.81±0.46, and 2.57±0.56 mm (<0.05). There was significantly more new bone formation in the COL/CELL group than in the CTL group, and new cementum length was also significantly higher in the COL/CELL group. However, there were no significant differences in the width of new cementum among the groups.

Conclusions: PDL progenitor cells carried by a synthetic collagen matrix may enhance periodontal regeneration, including cementum and new bone formation.
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http://dx.doi.org/10.5051/jpis.2019.49.4.215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6713806PMC
August 2019

Bone augmentation using small molecules with biodegradable calcium sulfate particles in a vertical onlay graft model in the rabbit calvarium.

J Biomed Mater Res B Appl Biomater 2020 05 30;108(4):1343-1350. Epub 2019 Aug 30.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Republic of Korea.

Small molecules including sodium butyrate (SB) and dimethyloxalylglycine (DMOG) can promote bone regeneration via inhibitive effects eliciting cellular responses through signaling cascades. The purpose of this study was to determine the synergistic effects of SB and DMOG loaded on calcium sulfate (CaS) on bone regeneration in the challenging vertical augmentation model in the rabbit calvarium. Four plastic cylinders screwed on the calvarium of each of 10 rabbits were randomly grafted with CaS, CaS/SB, CaS/DMOG, or CaS/DMOG/SB. All specimens were assessed by radiographic, histologic, and histomorphometric analyses. In the radiographic analysis, three different layers (new bone, degraded CaS, and pristine CaS layers) could be distinguished within the cylinder in all groups at 2 weeks. Newly formed bone grew up from basal bone, and CaS in contact with newly formed bone was degraded into small particles to form a different layer. At 8 weeks, most of the pristine CaS had been absorbed and hardly seen within the cylinder. In the histomorphometric analysis, all groups showed comparable new bone areas and heights at 2 and 8 weeks. The DMOG group showed a significant increase in new bone area at 8 weeks compared with 2 weeks, but there was no significant difference among the groups at 8 weeks. The DMOG group showed significantly lower values for the residual material area than the control group at 2 weeks. Within the limitations of this study, SB and DMOG seem to exert smaller synergistic effects on bone regeneration compared to CaS alone in vertical bone augmentation.
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http://dx.doi.org/10.1002/jbm.b.34483DOI Listing
May 2020

Clinical Factors and Cellular Responses of In Situ Human Alveolar Bone-Derived Mesenchymal Stromal Cells Associated With Early Periimplant Marginal Bone Loss: A Prospective Cohort Pilot Study.

Implant Dent 2019 Oct;28(5):421-429

Professor, Department of Applied Life Science, BK21 PLUS Project, College of Dentistry, Yonsei University, Seoul, Republic of Korea.

Purpose: To investigate clinical factors and cellular responses of in situ human alveolar bone-derived mesenchymal stromal cells involved in early periimplant marginal bone loss.

Materials And Methods: Thirty-seven completely or partially edentulous patients were enrolled in this study. Periapical radiographs were taken at the time of implant surgery, at 3-month follow-up, and at 1-year follow-up. Univariate analysis and multiple logistic regression were performed to investigate the associations between marginal bone loss and study variables. The mRNA expression levels of 21 bone-remodeling- and tissue-healing-associated genes were analyzed by subgroup.

Results: Thirty-one patients with 98 implants were followed. The incidence and mean amount of bone loss were higher for overdentures than for other prosthesis and higher for the maxilla than for the mandible. The bone loss group showed lower mRNA expression levels of runt-related transcription factor-2, bone morphogenetic protein-2, and peroxisome proliferator-activated receptor gamma-2 and higher receptor activator of NKκB ligand/osteoprotegerin (RANKL/OPG) ratio.

Conclusion: Within the limitations of the study, certain genes involved in bone remodeling (runt-related transcription factor-2 [Runx-2], bone morphogenetic protein-2 [BMP-2], and peroxisome proliferator-activated receptor gamma-2 [PPARγ-2]) and RANKL/OPG are correlated with early periimplant bone loss, with the type of suprastructure and the involved jaw being significant clinical factors.
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http://dx.doi.org/10.1097/ID.0000000000000904DOI Listing
October 2019

A retrospective case series evaluating the outcome of implants with low primary stability.

Clin Oral Implants Res 2019 Sep 24;30(9):861-871. Epub 2019 Jun 24.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Objectives: There is a need of more studies on whether low primary implant stability would negatively influence the success of implant therapy. Therefore, this retrospective study analyses outcomes of implants placed with low primary stability and factors that may be related to implant failures.

Material And Methods: This retrospective study included 156 patients, restored with 169 implants that presented manual rotation within an observed follow-up time of a minimum of 34 days and a maximum of 9.28 years. Descriptive statistics, survival analyses (life tables and Kaplan-Meier estimates) and radiographic assessment based on marginal bone level measurements were performed. This original study was adherent to STROBE guidelines.

Results: Seven implants failed in seven patients, rendering cumulative survival rates of 94.74% (95% CI: 89.11-97.50) and 94.33% (95% CI: 88.30-97.30) at implant and patient levels, respectively. Kaplan-Meier estimates showed implant loss was found only in advanced surgery group (7 implant loss in 82 implants) when compared with simple surgery group (no implant loss in 87 implants; p = 0.005).

Conclusions: Within the limitations of this retrospective study, implant placement with low primary stability might not negatively affect either the survival rates or marginal bone level changes of implants provided that a protected and unloaded healing is guaranteed.
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http://dx.doi.org/10.1111/clr.13491DOI Listing
September 2019

Long-term assessment of periodontal disease progression after surgical or non-surgical treatment: a systematic review.

J Periodontal Implant Sci 2019 Apr 19;49(2):60-75. Epub 2019 Apr 19.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

The primary aim of this systematic review was to assess the evidence on periodontal disease progression after treatment in patients receiving supportive periodontal therapy (SPT) and to identify predictors of clinical attachment level (CAL) loss. A protocol was developed to answer the following focused question: In adult patients treated for periodontitis, what is the disease progression in terms of CAL loss after surgical or non-surgical treatment? Randomized controlled clinical trials, prospective cohort studies, and longitudinal observational human studies with a minimum of 5 years of follow-up after surgical or non-surgical treatment that reported CAL and probing depth changes were selected. Seventeen publications reporting data from 14 investigations were included. Data from 964 patients with a follow-up range of 5-15 years was evaluated. When the CAL at the latest follow-up was compared to the CAL after active periodontal therapy, 10 of the included studies reported an overall mean CAL loss of ≤0.5 mm, 3 studies reported a mean CAL loss of 0.5-1 mm, and 4 studies reported a mean CAL loss of >1 mm. Based on 7 publications, the percentage of sites showing a CAL loss of ≥2 mm varied from 3% to 20%, and a high percentage of sites with CAL loss was associated with poor oral hygiene, smoking, and poor compliance with SPT. The outcomes after periodontal therapy remained stable over time. Disease progression occurred in a reduced number of sites and patients, mostly associated with poor oral hygiene, poor compliance with SPT, and smoking.
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http://dx.doi.org/10.5051/jpis.2019.49.2.60DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6494769PMC
April 2019

The effect of five mechanical instrumentation protocols on implant surface topography and roughness: A scanning electron microscope and confocal laser scanning microscope analysis.

Clin Oral Implants Res 2019 Jun 7;30(6):578-587. Epub 2019 May 7.

Section of graduate Periodontology, Faculty of Odontology, Complutense University of Madrid, Madrid, Spain.

Objective: To evaluate in vitro the changes in implant surface topography and roughness of commercial implants after instrumentation with five decontamination protocols.

Material And Methods: Seventy-two titanium implants with a sandblasted and acid-etched (SLA) surface were placed 5 mm supra-crestally. Five groups of twelve implants were instrumented with the following protocols: a metal scaler tip (SCAL), a thermoplastic scaler tip (PEEK), a round titanium brush (RBRU), a tufted brush with titanium bristles (TNBRU), and a glycine-based air-powder abrasive (GLYC). A sixth group with untreated implants was used as control. Scanning electron microscope and confocal laser scanning microscope were utilized to evaluate the changes in the implant surfaces.

Results: The SCAL caused pronounced macroscopic alterations and damage of the implant surface, the PEEK left remnants of the plastic tip in the implant surface, and both titanium brush groups flattened the thread profile, while minimal alterations were observed in the GLYC. When compared to the control group, the roughness parameters (Sa) in the buccal aspect increased in the thread area of SCAL, and a minor reduction was observed in the PEEK while in the other groups, these values remained unchanged. In the valley areas, however the RBRU, TNBRU, and GLYC experienced a significant reduction (smoothening) indicating different accessibility of the decontamination protocols to the thread and valley. Similarly, the buccal aspects had more pronounced changes than those in the palatal aspect.

Conclusion: Within the limitations of this in vitro investigation, the tested protocols induced different macroscopic alterations and surface roughness changes that varied in the thread and valley area.
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http://dx.doi.org/10.1111/clr.13446DOI Listing
June 2019

Alveolar ridge preservation in the posterior maxilla reduces vertical dimensional change: A randomized controlled clinical trial.

Clin Oral Implants Res 2019 Jun 13;30(6):515-523. Epub 2019 May 13.

Department of Fixed and Removable Prosthodontics and Dental Material Science, Dental School, University of Zurich, Zurich, Switzerland.

Objectives: To test whether or not alveolar ridge preservation reduces vertical changes in the posterior maxilla compared to spontaneous healing following tooth extraction.

Materials And Methods: Forty subjects requiring extraction of maxillary posterior teeth with root apices protruding into the maxillary sinus floor were consecutively enrolled. Patients were randomly assigned to either one of two surgical interventions: an alveolar ridge preservation procedure using collagenated bovine bone mineral and a resorbable collagen membrane (test) or no grafting (control). Cone-beam computed tomographies were taken immediately and at 6 months after surgery, prior to dental implant placement.

Results: Based on radiographic data, the level of the sinus floor remained stable over time (baseline to 6 months) in the test group (-0.14 mm [-0.31, -0.02]). In the control group, the sinus floor level shifted more coronally (-1.16 mm [-1.73, -0.61]) than the test group (p < 0.05). The test group demonstrated a significantly larger residual bone height than the control group at 6 months (7.30 mm [6.36, 8.20] vs. 4.83 mm [3.94, 5.76], respectively, p < 0.05). Implant placement without any additional sinus augmentation procedure was performed in 42.9% of test group cases, whereas in all of the subjects in the control group an additional augmentation procedure was needed (100% of the cases).

Conclusion: Alveolar ridge preservation in the posterior maxilla maintained the vertical bone height more efficiently and resulted in less need for sinus augmentation procedures at 6 months compared to spontaneous healing.
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http://dx.doi.org/10.1111/clr.13436DOI Listing
June 2019

Maxillary sinus augmentation using biphasic calcium phosphate: dimensional stability results after 3-6 years.

J Periodontal Implant Sci 2019 Feb 26;49(1):47-57. Epub 2019 Feb 26.

Department of Periodontology, Research Institute for Periodontal Regeneration, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: This study was designed to observe the resorption pattern of biphasic calcium phosphate (BCP) used for maxillary sinus augmentation over a 3- to 6-year healing period, and to investigate factors affecting the resorption of BCP.

Methods: A total of 47 implants placed in 27 sinuses of 22 patients were investigated. All patients had residual bone height less than 5 mm at baseline. The modified Caldwell-Luc approach was used to elevate the maxillary sinus membrane, and the sinus cavity was filled with BCP (70% hydroxyapatite and 30% β-tricalcium phosphate). Implant placement was done simultaneously or in a staged manner. Serial radiographic analysis was performed up to 6 years postoperatively.

Results: During the follow-up period, no implant loss was reported. The mean reduced height of the augmented sinus (RHO) was 0.27±1.08 mm at 36 months, and 0.89±1.39 mm at 72 months postoperatively. Large amounts of graft material (=0.021) and a long healing period (=0.035) significantly influenced the amount of RHO. In particular, there was a significant relationship between a healing period longer than 40 months and RHO.

Conclusions: BCP can achieve proper dimensional stability with minimal reduction of the graft height in a 3- to 6-year healing period after maxillary sinus augmentation. The healing period and the amount of graft material influenced the resorption of BCP.
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http://dx.doi.org/10.5051/jpis.2019.49.1.47DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6399091PMC
February 2019