Purpose: The Korean Oral Biobank Network (KOBN) collects, stores, and provides oral samples for research. Quality control (QC) of biospecimens is necessary to ensure that they meet the basic prerequisites before being sent to researchers. This study presents the standard operating procedures (SOPs) for the QC of biospecimens. Methods: QC methods using molecular genetic techniques according to sample types, including teeth, blood, oral soft tissue, oral tissue-derived cells, saliva, mouth rinse solution, dental plaque, and gingival crevicular fluid, are described in detail. Results: The KOBN established SOP for oral biospecimen QC and assessment methods. Conclusions To ensure a stable supply of high-quality biospecimens for researchers, regular QC checks should be carried out according to the SOP following the specifications of the Korea Biobank Network under the Korea Disease Control and Prevention Agency.

Purpose: Root coverage (RC) procedures require long-term evaluation. This study assessed the clinical validity and long-term stability of a modified tunneling technique for lower anterior gingival recession (GR) using a subepithelial connective tissue graft (SCTG) and a volume-stable collagen matrix. Methods: Across 39 patients, 66 mandibular incisors with ≥1.0 mm of GR were examined before and after RC surgery. Clinical photographs documenting the results of RC were taken at baseline (T0 ) and the most recent follow-up visit (T l ). Impressions were obtained either at baseline (T0 ) or 3 weeks later (T 3 ). The recession depth, Miller classification, and rates of RC and complete root coverage (CRC) were assessed. Results: This study analyzed 66 GR sites across 39 patients, with an average follow-up period of 41.3 months. Overall, the mean RC achieved was 86.2%±15.7%. Among single recessions, the RC was 85.2%±25.6% for Miller class I, 91.5%±10.4% for class II, and 79.2%±18.3% for class III. Regarding multiple recessions, the RC was 85.1%±16.2% for Miller class I, 87.0%±12.5% for class II, and 89.8%±16.0% for class III. By Miller classification, the RC was 85.1%±16.8% for class I, 88.7%±11.6% for class II, and 85.8%±17.3% for class III.Furthermore, the RC varied by follow-up duration: 72.5%±15.1% at 12 months, 90.1%±12.6% at 25–36 months, 89.0%±16.7% at 37–48 months, 91.10%±9.88% at 49–60 months, and 97.6±4.79% for longer than 61 months, with 77.8% of the last group achieving CRC. RC also differed based on the initial recession depth, at 88.0%±16.8% for 1–3 mm, 83.1%±14.1% for 3–6 mm, and 80.2%±5.04% for depths exceeding 6 mm. Conclusions A modified tunneling technique, utilizing SCTG and a volume-stable collagen matrix, appears to represent a reliable option for the long-term management of GR in the lower anterior region, even in cases involving multiple Miller class III GRs.

Purpose: A small magnetic peg, named “BracketPeg,” has been developed as an attachment magnet for implant prostheses. This study aimed to determine the feasibility of measuring implant stability at the prosthesis level, evaluate the reliability and accuracy of BracketPeg, and examine the consistency of measurements obtained using other devices for damping capacity assessment (DCA) and resonance frequency analysis (RFA). Methods: Forty implants were installed into artificial bone blocks, with each block representing 1 of 4 different diameters (3.5, 4.0, 4.5, and 5.5 mm; 10 implants per diameter).Each implant was paired with a customized zirconia prosthesis that matched the implant diameter. Implant stability was measured at both the fixture and prosthesis levels using Anycheck™ (Neobiotech) for DCA and Osstell™ Beacon (W&H) and ChecQ™ (Dentis) for RFA. To obtain prosthesis-level measurements using RFA devices, BracketPeg was attached to the coronal, middle, and apical thirds of the prosthesis to evaluate implant stability. Results: The implant stability quotient (ISQ) was significantly lower at the prosthesis level than at the fixture level (P<0.001), reflecting the impact of the increased mass and size of the prosthesis. RFA values varied depending on the position of BracketPeg, with lower stability values observed at the coronal position than at the apical position. The 2 RFA devices demonstrated reasonable agreement between ISQ measurements, with a mean difference of −0.58 (95% confidence interval: ±0.31). Conclusions BracketPeg provides reliable and consistent implant stability measurements at the prosthesis level compared to other devices, making it a practical and feasible tool for the clinical evaluation of implants.

Purpose: Gingival fibroblasts are a major cellular component of the connective tissue and play a crucial role in wound healing and tissue regeneration through collagen synthesis.This study aimed to assess the effect of polynucleotide (PN) combined with cross-linked hyaluronic acid (HA) on the proliferation, differentiation, and anti-inflammatory responses of human gingival fibroblasts-1 (HGF-1). Methods: In this in vitro experimental study, HGF-1 cells were cultured with PN/HA, PN, HA, and enamel matrix derivative (EMD). Cell proliferation and migration were assessed at 24 hours and 48 hours, respectively. Long-term cultures were evaluated for collagen and proteoglycan deposition using sirius red and alcian blue staining. Levels of phospho-nuclear factor-κB (NF-κB) p65, collagen type I (Col 1), and interleukin-6 (IL-6) were measured using Western blot analysis or enzyme-linked immunosorbent assay. Results: All experimental groups exhibited increased cellular proliferation and migration compared to the control group. Similar to EMD, PN/HA promoted the synthesis of Col 1 and proteoglycans. At concentrations of 2.5 mg/mL for PN and HA, and 1.0 mg/mL for PN/HA, significant anti-inflammatory effects were observed. These effects included reductions in phospho-NF-κB p65 levels and IL-6 production when exposed to lipopolysaccharides from Porphyromonas gingivalis. EMD, however, did not demonstrate these anti-inflammatory effects. Conclusions Within the limitations of this study, we concluded that PN/HA improves gingival tissue healing by promoting cell proliferation and migration, facilitating rapid collagen deposition, and exerting anti-inflammatory effects.

Purpose: This retrospective study aimed to evaluate the long-term survival rate and marginal bone loss (MBL) of tapered-straight-tapered dental implants, considering various associated factors, over an observational period of ≥5 years. Methods: This study included 186 patients who underwent tapered-straight-tapered dental implant placement at Seoul National University Dental Hospital from 2014 to 2019. Digital panoramic radiographic images and dental records were examined. We evaluated multiple variables, such as sex, age, diabetes mellitus (DM), smoking status, placement region, jaw type (maxilla and mandible), implant diameter, implant length, staged surgery, immediate placement, splinted prosthesis, and implant placement depth (IPD). We first determined the implant survival rate using Kaplan–Meier analysis and analyzed potential risk factors for implant survival using mixed-effects Cox proportional hazards regression. Next, the Mann– Whitney and Kruskal–Wallis tests were used to examine differences in MBL across variables.Linear mixed-effects models with backward stepwise selection were used to identify associations between risk factors and MBL. Results: This study included 316 implants in 186 patients, monitored over a follow-up period of 7.0±1.36 years. The cumulative survival rate of the implants was 98.1%. The average mesial and distal MBLs were 0.59±1.36 mm and 0.68±1.36 mm, respectively. Linear mixed-effects models indicated that MBL exhibited statistically significant positive correlations with DM (Coeff.=0.614, P=0.026) and staged surgery (Coeff.=0.410, P=0.002). Additionally, greater mesial IPD was associated with reduced MBL (Coeff.=−0.143, P=0.046), and a similar trend was observed for distal IPD (Coeff.=−0.316, P=0.068). Conclusions This study demonstrated a high cumulative survival rate for tapered-straighttapered dental implants over a 5-year period. DM, staged surgery, and IPD showed strong associations with increased MBL. The results suggest that tapered-straight-tapered implants offer advantages in terms of peri-implant MBL and consistent clinical outcomes. These findings underscore the importance of considering these variables in clinical decisionmaking to optimize implant outcomes.

Purpose: Immediate implant placement (IIP) offers several advantages, including minimizing hard and soft tissue deformation, reducing implant time and cost, and rapidly restoring tooth function. However, IIP is technically challenging due to the need to secure initial stability and limit functional loading during healing. Therefore, this study aimed to evaluate the clinical outcomes of a bone-level implant featuring a dual thread design—an upper U-shaped thread and a lower V-shaped thread—with an 11° internal hexagonal connection in IIP within the maxillary esthetic zone. Methods: This study included 20 patients. Implants were inserted immediately after tooth extraction. Soft tissue changes were evaluated before tooth extraction (V0), after IIP (V1), at prosthesis delivery (V5), at a 3-month follow-up after prosthesis delivery (V6), and at a 1-year follow-up (V8). Bone dimensional changes were assessed at V1 and V8 using cone beam computed tomography, and the marginal bone level (MBL) was evaluated at V6 and V8 using 2-dimensional. Results: Of the 20 patients, 3 dropped out due to osseointegration failure during the followup period. Although the horizontal dimensions of the soft and hard tissues decreased slightly, the gingival margin and MBL remained well maintained throughout the follow-up. Conclusions Within this limited dataset, the lower V-shaped thread enabled favorable initial stability in IIP, and the esthetic outcomes were positive—with minimal gingival recession and marginal bone loss. Long-term follow-up is required to fully assess the impact of thread design and connection on esthetics.

Following tooth extraction, inevitable hard and soft tissue remodeling leads to buccal contour loss, and complete prevention remains challenging despite strategies including ridge preservation, immediate implant placement and bone grafting. To rehabilitate the contour loss, soft tissue augmentation with a collagen matrix is widely performed to increase crestal mucosal thickness. In addition, the use of customized healing abutment (HA) contributes to establishing harmonious buccal transmucosal margin with an adjacent natural tooth. This case report presents two cases in which ridge contour loss following extraction and implant placement that were reconstructed to the pre-extraction contour synergistically via soft tissue augmentation and customized HA. Horizontal soft tissue thickness changes were quantitatively assessed by superimposing stereolithographic files obtained from sequential intraoral scans, and the rehabilitation rate was calculated. At 3 months postoperatively, the rehabilitation rate at the 5-mm measurement point was 52.9% in Case 1 treated with a bilayer collagen matrix, and 102.9% in Case 2 treated with a volume-stable collagen matrix for soft tissue augmentation. With combined use of customized HA, the present cases established harmonious peri-implant mucosal architecture and emergence profiles of implant restoration.

Purpose: This retrospective study aimed to assess the long-term cumulative survival rate of titanium, sandblasted, large-grit, acid-etched implants over a 10-year follow-up period and investigate the factors affecting the survival rate and change in marginal bone loss (MBL). Methods: The study included 400 patients who underwent dental implant placement at the Department of Periodontology of Seoul National University Dental Hospital (SNUDH) between 2005 and 2015. Panoramic radiographic images and dental records of patients were collected and examined using Kaplan-Meier analysis, Cox proportional hazards regression analysis, and multiple regression analysis to determine the survival rates and identify any factors related to implant failure and MBL. Results: A total of 782 implants were placed with a follow-up period ranging from 0 to 16 years (mean: 8.21±3.75 years). Overall, 25 implants were lost, resulting in a cumulative survival rate of 96.8%. Comparisons of the research variables regarding cumulative survival rate mostly yielded insignificant results. The mean mesial and distal MBLs were 1.85±2.31 mm and 1.59±2.03 mm, respectively. Factors influencing these values included age, diabetes mellitus (DM), jaw location, implant diameter, bone augmentation surgery, and prosthetic unit. Conclusions This study found that the implant survival rates at SNUDH fell within the acceptable published criteria. The patients’ sex, age, DM status, implant location, implant design, implant size, surgical type, bone augmentation, and prosthetic unit had no discernible influence on long-term implant survival. Sandblasted, large-grit, acid-etched implants might offer advantages in terms of implant longevity and consistent clinical outcomes.

Purpose: This study aimed to evaluate the clinical outcomes of a single type of narrowdiameter implant (NDI) by investigating its survival rate and peri-implant marginal bone loss (MBL). In addition, variables possibly related to implant survival and MBL were investigated to identify potential risk factors. Methods: The study was conducted as a retrospective study involving 49 patients who had received 3.0-mm diameter TSIII implants (Osstem Implant Co.) at Seoul National University Dental Hospital. In total, 64 implants were included, and dental records and radiographic data were collected from 2017 to 2022. Kaplan-Meier survival curves and a Cox proportional hazard model were used to estimate the implant survival rate and to investigate the effects of age, sex, jaw, implant location, implant length, the stage of surgery, guided bone regeneration, type of implant placement, and the surgeon’s proficiency (resident or professor) on implant survival. The MBL of the NDIs was measured, and the factors influencing MBL were evaluated. Results: The mean observation period was 30.5 months (interquartile range, 26.75–45 months), and 6 out of 64 implants failed. The survival rate of the NDIs was 90.6%, and the multivariate Cox regression analysis showed that age was associated with implant failure (hazard ratio, 1.17; 95% confidence interval, 1.04–1.31, P=0.01). The mean MBL was 0.44±0.75 mm, and no factors showed statistically significant associations with greater MBL. Conclusions NDIs can be considered a primary alternative when standard-diameter implants are unsuitable. However, further studies are required to confirm their long-term stability.

Purpose: This study aimed to evaluate the long-term cumulative survival rate (CSR) of dental implants with micro-threads in the neck over a 10-year follow-up period and to examine the factors influencing the survival rate of dental implants. Methods: This retrospective study was based on radiographic and dental records. In total, 151 patients received 490 Oneplant ® dental implants with an implant neck micro-thread design during 2006–2010 in the Department of Periodontology of Seoul National University Dental Hospital. Implant survival was evaluated using Kaplan–Meier analysis. Cox proportional hazard regression analysis was used to identify the factors influencing implant failure. Results: Ten out of 490 implants (2.04%) failed due to fixture fracture. The CSR of the implants was 97.9%, and no significant difference was observed in the CSR between externaland internal-implant types (98.2% and 97.6%, respectively,P=0.670). In Cox regression analysis, 2-stage surgery significantly increased the risk of implant failure (hazard ratio: 4.769, P=0.039). There were no significant differences in influencing factors, including sex, age, implant diameter, length, fixture type, location, surgical procedure, bone grafting, and restoration type. Conclusions Within the limitations of this retrospective study, the micro-thread design of the implant neck was found to be favorable for implant survival, with stable clinical outcomes.