Publications by authors named "Ui-Won Jung"

195 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

Intranuclear Delivery of Nuclear Factor-Kappa B p65 in a Rat Model of Tooth Replantation.

Int J Mol Sci 2021 Feb 17;22(4). Epub 2021 Feb 17.

Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Korea.

After avulsion and replantation, teeth are at risk of bone and root resorption. The present study aimed to demonstrate that the intra-nuclear transducible form of transcription modulation domain of p65 (nt-p65-TMD) can suppress osteoclast differentiation in vitro, and reduce bone resorption in a rat model of tooth replantation. Cell viability and nitric oxide release were evaluated in RAW264.7 cells using CCK-8 assay and Griess reaction kit. Osteoclast differentiation was evaluated using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and tartrate-resistant acid phosphatase (TRAP) staining. Thirty-two maxillary rat molars were extracted and stored in saline ( = 10) or 10 µM nt-p65-TMD solution ( = 22) before replantation. After 4 weeks, specimens were scored according to the inflammatory pattern using micro-computed tomography (CT) imaging and histological analyses. nt-p65-TMD treatment resulted in significant reduction of nitric oxide release and osteoclast differentiation as studied using PCR and TRAP staining. Further, micro-CT analysis revealed a significant decrease in bone resorption in the nt-p65-TMD treatment group ( < 0.05). Histological analysis of nt-p65-TMD treatment group showed that not only bone and root resorption, but also inflammation of the periodontal ligament and epithelial insertion was significantly reduced. These findings suggest that nt-p65-TMD has the unique capabilities of regulating bone remodeling after tooth replantation.
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http://dx.doi.org/10.3390/ijms22041987DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7922502PMC
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

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

Development of Lidocaine-Loaded Dissolving Microneedle for Rapid and Efficient Local Anesthesia.

Pharmaceutics 2020 Nov 9;12(11). Epub 2020 Nov 9.

JUVIC Inc., No. 208, Digital-ro 272, Guro-gu, Seoul 08389, Korea.

Lidocaine is a local anesthetic agent used in the form of injection and topical cream. However, these formulation types have limitations of being either painful or slow-acting, thereby hindering effective and complete clinical performance of lidocaine. Dissolving microneedles (DMNs) are used to overcome these limitations owing to their fast onset time and minimally invasive administration methods. Using hyaluronic acid and lidocaine to produce the drug solution, a lidocaine HCl encapsulated DMN (Li-DMN) was fabricated by centrifugal lithography. The drug delivery rate and local anesthetic quality of Li-DMNs were evaluated using the pig cadaver insertion test and Von Frey behavior test. Results showed that Li-DMNs could deliver sufficient lidocaine for anesthesia that is required to be utilized for clinical level. Results from the von Frey test showed that the anesthetic effect of Li-DMNs was observed within 10 min after administration, thus confirming fast onset time. A toxicity test for appropriate clinical application standard was conducted with a microbial limit test and an animal skin irritation test, showing absence of skin irritation and irritation-related microorganisms. Overall, Li-DMN is a possible alternative drug delivery method for local anesthesia, meeting the requirements for clinical conditions and overcoming the drawbacks of other conventional lidocaine administration methods.
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http://dx.doi.org/10.3390/pharmaceutics12111067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695299PMC
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

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

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

Dissolving Microneedles for Rapid and Painless Local Anesthesia.

Pharmaceutics 2020 Apr 17;12(4). Epub 2020 Apr 17.

Department of Biotechnology, Building 123, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.

Microneedles are emerging drug delivery methods for painless treatment. The current study tested dissolving microneedles containing lidocaine (Li-DMN) for use in local anesthesia. An Li-DMN patch was fabricated by centrifugal lithography with carboxymethyl cellulose as a structural polymer and assessed for physical properties by optical microscopy and a fracture force analyzer. The biocompatibility was evaluated by a histology section in vitro and by ear thickness in vivo. The efficacy of the Li-DMN patch was assessed by electrophysiological recordings in primary cultured sensory neurons in vitro and a von Frey test on rats' hind paws in vivo. The physical properties of the microneedle showed enough rigidity for transdermal penetration. The maximal capacity of lidocaine-HCl in the Li-DMN patch was 331.20 ± 6.30 µg. The cytotoxicity of the dissolving microneedle to neuronal cells was negligible under an effective dose of lidocaine for 18 h. Electrophysiological recordings verified the inhibitory effect of the voltage-gated sodium channel current by the Li-DMN patch in vitro. A skin reaction to the edema test and histologic analysis of the rats' ears after application of the Li-DMN patch were negligible. Also, the application of the Li-DMN patch reduced the nocifensive behavior of the rats almost immediately. In conclusion, the dissolving microneedle patch with carboxymethyl cellulose is a promising candidate method for the painless delivery of lidocaine-HCl.
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http://dx.doi.org/10.3390/pharmaceutics12040366DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7238259PMC
April 2020

Alveolar bone height according to the anatomical relationship between the maxillary molar and sinus.

J Periodontal Implant Sci 2020 Feb 28;50(1):38-47. Epub 2020 Jan 28.

Department of Oral and Maxillofacial Radiology, Yonsei University College of Dentistry, Seoul, Korea.

Purpose: The aim of this study was to investigate the available alveolar bone height between the maxillary molars and the sinus floor according to their anatomical relationship using cone-beam computed tomographic (CBCT) images.

Methods: A total of 752 maxillary first (M1) and second molars (M2) on CBCT scans of 188 patients were selected. First, each maxillary molar was categorized as type 1, 2, 3, or 4 according to the relationship of the molar root with the maxillary sinus floor. The frequency distribution of each type was analyzed. Second, the shortest vertical distance (VD) of each molar was measured from the furcation midpoints of the roots to the lowest point of the sinus floor by 2 observers. Intraclass correlation coefficients and the t-test were calculated for the VD measurements.

Results: For M1, type 3 was the most frequent, followed by type 2. For M2, type 3 was the most common, followed by type 1. The VD measurements of type 1 were 9.51±3.68 mm and 8.07±2.73 mm for M1 and M2, and those of type 3 were 3.70±1.52 mm and 4.03±1.53 mm for M1 and M2, respectively. The VD measurements of M2 were significantly higher in female patients than in male patients.

Conclusions: Type 3 was the most frequent anatomical relationship in the maxillary molars, and showed the lowest alveolar bone height. This information will help clinicians to prevent complications related to the maxillary sinus during maxillary molar treatment and to predict the available bone height for immediate implant planning.
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http://dx.doi.org/10.5051/jpis.2020.50.1.38DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040445PMC
February 2020

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

Red fluorescence of Interdental plaque for screening of gingival health.

Photodiagnosis Photodyn Ther 2020 Mar 7;29:101636. Epub 2020 Jan 7.

Department of Preventive Dentistry & Public Oral Health, BK21 PLUS Project, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea. Electronic address:

Background: Pathogenic dental plaque with deteriorated bacterial homeostasis around the gingival margin induces gingivitis. This study evaluated the applicability of red fluorescence (RF) properties of interdental plaque in screening for gingival health status.

Methods: This cross-sectional study examined 178 teeth of 40 healthy subjects who had not lost both their first and second molars in at least one quadrant. Three groups (healthy, gingivitis, and periodontitis) were identified based on the periodontal health status (bleeding on probing, probing depth, clinical attachment loss) and plaque accumulation level (plaque index) in the interdental site between the first and second molars was evaluated. This interdental plaque between the first (distal surface) and the second molar (mesial surface) was collected using dental floss. A quantitative light-induced fluorescence (QLF) technology was used to assess RF emitted from the interdental plaque. The RF properties of the interdental plaque were quantified by fluorescence intensity (R/G value) and area (%). The RF variables were compared between the groups.

Results: The RF variables of the interdental plaque (R/G value and area) were significantly higher in the gingivitis and periodontitis group compared to the healthy group (p<0.0001, p=0.001), but there was no significant difference between the gingivitis and periodontitis groups. Significant correlations were identified between R/G value and bleeding on probing (r = 0.49, P < 0.01) and between R/G value and visual plaque index (r = 0.59, P < 0.01) for each tooth.

Conclusion: Interdental plaque obtained by flossing and its red fluorescence quantified by QLF technology could be used as a potential indicator of gingivitis.
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http://dx.doi.org/10.1016/j.pdpdt.2019.101636DOI Listing
March 2020

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

Effect of teriparatide on early sinus graft healing in the ovariectomized rabbit.

Clin Oral Implants Res 2020 Mar 3;31(3):264-273. Epub 2020 Jan 3.

Department of Advanced General Dentistry, College of Dentistry, Yonsei University, Seoul, Korea.

Objectives: The purpose of this study was to determine the effect of administering intermittent parathyroid hormone 1-34 [teriparatide, (PTH)] on the maxillary sinus lift and bone grafting in osteoporotic rabbits induced by ovariectomy and glucocorticoid.

Materials And Methods: Ovariectomies were performed on 20 female New Zealand white rabbits that were randomly divided into two groups: (a) the PTH group (n = 10), in which 10 μg kg  day PTH was injected subcutaneously 5 days a week for 5 weeks (from 1 week before until 4 weeks after sinus surgery), and (b) the saline group (n = 10), in which saline substituted PTH at the same dose, mode of administration, and duration. Bone grafting with bovine bone mineral was augmented into 13 sinuses, and bone grafts and implants were simultaneously performed in seven sinuses, in both groups. Animals were sacrificed at 4 weeks after surgery. To determine whether PTH was an effective treatment for osteoporosis, we measured the bone mineral density (BMD) of the right femur using micro-computed tomography and performed radiographic and histometric analyses of the maxillary sinus surgery site. The Mann-Whitney test was used for statistical analysis.

Results: It was found that BMD increased in the femur, whereas none of the radiographic and histometric parameters differed significantly between the groups in the sinus, while there were large interindividual variations within groups.

Conclusions: These findings suggest that intermittent PTH does not promote new bone formation in the augmented maxillary sinus of ovariectomized rabbits.
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http://dx.doi.org/10.1111/clr.13565DOI Listing
March 2020

Evaluation of the Apical Complex and the Coronal Pulp as a Stem Cell Source for Dentin-pulp Regeneration.

J Endod 2020 Feb 10;46(2):224-231.e3. Epub 2019 Dec 10.

Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Republic of Korea. Electronic address:

Introduction: This study compared the stemness and differentiation potential of stem cells derived from the apical complex (apical complex cells [ACCs]) and coronal pulp (dental pulp stem cells [DPSCs]) of human immature permanent teeth with the aim of determining a more suitable source of stem cells for regeneration of the dentin-pulp complex.

Methods: ACC and DPSC cultures were established from 13 human immature permanent teeth using the outgrowth method. The proliferation capacity and colony-forming ability of ACCs and DPSCs were evaluated. ACCs and DPSCs were analyzed for mesenchymal stem cell markers using flow cytometry. The adipogenic and osteogenic differentiation potential of ACCs and DPSCs were evaluated using the quantitative real-time polymerase chain reaction and histochemical staining. ACCs and DPSCs were transplanted subcutaneously in immunocompromised mice using macroporous biphasic calcium phosphate as a carrier. The histomorphologic characteristics of the newly formed tissues were verified using hematoxylin-eosin staining and immunohistochemical staining. Quantitative alkaline phosphatase analysis and quantitative real-time polymerase chain reaction using BSP, DSPP, POSTN, and ColXII were performed.

Results: ACCs and DPSCs showed similar cell proliferation potential and colony-forming ability. The percentage of mesenchymal stem cell markers was similar between ACCs and DPSCs. In the in vitro study, ACCs and DPSCs showed adipogenic and osteogenic differentiation potential. In the in vivo study, ACCs and DPSCs formed amorphous hard tissue using macroporous biphasic calcium phosphate particles. The quantity and histomorphologic characteristics of the amorphous hard tissue were similar in the ACC and DPSC groups. Formation of periodontal ligament-like tissue, positive to Col XII, was observed in ACC transplants, which was absent in DPSC transplants.

Conclusions: ACCs and DPSCs showed similar stemness, proliferation rate, and hard tissue-forming capacity. The notable difference was the periodontal ligament-like fiber-forming capacity of ACCs, which indicates the presence of various lineages of stem cells in the apical complex compared with the coronal pulp. Regarding regeneration of the dentin-pulp complex, the coronal pulp can be a suitable source of stem cells considering its homogenous lineages of cells and favorable osteo/odontogenic differentiation potential.
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http://dx.doi.org/10.1016/j.joen.2019.10.025DOI Listing
February 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

Monolithic Zirconia FPD on Modified Titanium Bonding Bases in Limited Interocclusal Distance: A Case Report.

J Oral Implantol 2020 Feb;46(1):57-61

Department of Prosthodontics, College of Dentistry, Yonsei University, Seoul, Korea.

A 62-year-old male patient sought treatment for missing maxillary teeth. A diagnostic cast demonstrated that the interocclusal distance was insufficient. A 5-unit screw-retained implant-supported fixed partial denture (FPD) was used to restore missing maxillary teeth. The restoration of multiple missing teeth using an implant-supported FPD is challenging when the interocclusal distance is limited due to lack of retention and inadequate esthetics. In this case, a hexagonal, screw-retained, and subgingivally located titanium-based zirconia implant-supported FPD with a conical abutment base was used for restoration to overcome the limited interocclusal distance. This implant-supported FPD, consisting of CAD/CAM-designed monolithic zirconia cemented to a titanium bonding base in the laboratory, is expected to facilitate predictable retention and adequate esthetics as well as provide ease of retrieval.
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http://dx.doi.org/10.1563/aaid-joi-D-19-00103DOI Listing
February 2020

Augmentation of keratinized tissue at tooth and implant sites by using autogenous grafts and collagen-based soft-tissue substitutes.

J Clin Periodontol 2020 01 28;47(1):64-71. Epub 2019 Oct 28.

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

Aim: To investigate the effect of three treatment modalities on the gain of keratinized tissue (KT) at tooth and implant sites in dogs.

Materials And Methods: In five dogs, the distal roots of the mandibular second, third and fourth premolars were extracted, while the mesial roots were maintained. After 2 months of healing, implants were placed with KT excision. After another 2 months of healing, free gingival grafts, collagen-based matrices and apically positioned flap only were applied. The height of KT was measured during implant placement, immediately before soft-tissue grafting and after 10, 30 and 60 days.

Results: Two months after KT excision, spontaneous KT regrowth was greater at tooth sites than at implant sites (median, 2.0 mm vs. 1.1 mm). The outcomes of soft-tissue grafting at implant sites favoured the free gingival graft treatment, with a greater final median height (5.0-5.5 mm) and increase in KT (4.0-4.2 mm). Locations of the recipient sites significantly influenced KT regeneration at both tooth and implant sites.

Conclusions: At implant sites, the free gingival graft treatment led to higher KT regeneration. At tooth sites, however, the differences between the three treatment modalities seemed clinically irrelevant.
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http://dx.doi.org/10.1111/jcpe.13194DOI Listing
January 2020

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

The effects of hard and soft tissue grafting and individualization of healing abutments at immediate implants: an experimental study in dogs.

J Periodontal Implant Sci 2019 Jun 7;49(3):171-184. Epub 2019 Jun 7.

Department of Periodontology, Julius-Maximilians-University of Würzburg, Würzburg, Germany.

Purpose: To evaluate the effects of intra-alveolar socket grafting, subepithelial connective tissue grafts, and individualized abutments on peri-implant hard and soft tissue outcomes following immediate implant placement.

Methods: This randomized experimental study employed 5 mongrel dogs, with 4 sites per dog (total of 20 sites). The mesial roots of P3 and P4 were extracted in each hemimandible and immediate dental implants were placed. Each site was randomly assigned to 1 of 4 different treatment groups: standardized healing abutment (control group), alloplastic bone substitute material (BSS) + standardized healing abutment (SA group), BSS + individualized healing abutment (IA group), and BSS + individualized healing abutment + a subepithelial connective tissue graft (IAG group). Clinical, histological, and profilometric analyses were performed. The intergroup differences were calculated using the Bonferroni test, setting statistical significance at <0.05.

Results: Clinically, the control and SA groups demonstrated a coronal shift in the buccal height of the mucosa (0.88±0.48 mm and 0.37±1.1 mm, respectively). The IA and IAG groups exhibited an apical shift of the mucosa (-0.7±1.15 mm and -1.1±0.96 mm, respectively). Histologically, the SA and control groups demonstrated marginal mucosa heights of 4.1±0.28 mm and 4.0±0.53 mm relative to the implant shoulder, respectively. The IA and IAG groups, in contrast, only showed a height of 2.6 mm. In addition, the height of the mucosa in relation to the most coronal buccal bone crest or bone substitute particles was not significantly different among the groups. Volumetrically, the IA group (-0.73±0.46 mm) lost less volume on the buccal side than the control (-0.93±0.44 mm), SA (-0.97±0.73 mm), and IAG (-0.88±0.45 mm) groups.

Conclusions: The control group demonstrated the most favorable change of height of the margo mucosae and the largest dimensions of the peri-implant soft tissues. However, the addition of a bone substitute material and an individualized healing abutment resulted in slightly better preservation of the peri-implant soft tissue contour.
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http://dx.doi.org/10.5051/jpis.2019.49.3.171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6599753PMC
June 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

Tissue integration of zirconia and titanium implants with and without buccal dehiscence defects-A histologic and radiographic preclinical study.

Clin Oral Implants Res 2019 Jul 12;30(7):660-669. Epub 2019 May 12.

Clinic for Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zurich, Switzerland.

Objective: To histologically and radiographically evaluate soft (primary outcome) and hard tissue integration of two-piece titanium and zirconia dental implants with/without buccal dehiscence defects.

Materials & Methods: In six dogs, five implants were randomly placed on both sides of the mandible: (a) Z1: a zirconia implant (modified surface) within the bony housing, (b) Z2: a zirconia implant (standard surface) within the bony housing, (c) T: a titanium implant within the bony housing, (d) Z1_D: a Z1 implant placed with a buccal bone dehiscence (3 mm in height, identical width to implant body), and (e) T_D: a titanium implant placed with a buccal bone dehiscence. Two weeks of healing and 6 months of loading were applied on each hemi-mandible, respectively.

Results: The median level of the margo mucosae shifted more apically over time in all groups (borderline statistical significance in groups Z1_D: -0.52 mm and T_D: -1.26 mm). The median height of the peri-implant mucosa in groups Z1_D and T_D was greatest at 2 weeks and 6 months, but the linear change in the peri-implant mucosa was statistically significant only for group T_D over time (-1.45 mm). Z1 demonstrated a higher bone-to-implant contact compared to Z2 and T. Minimal change of radiographic marginal bone levels in all groups was observed (<1 mm).

Conclusion: When buccal dehiscence was presented, titanium implants presented significant loss of peri-implant mucosal height compared to zirconia implants with a modified surface, due to greater apical shift of the margo mucosae. A modified zirconia surface enhanced osseointegration.
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http://dx.doi.org/10.1111/clr.13451DOI Listing
July 2019