A paradigm shift in medical care

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골유도 재생술과 임프란트 식립을 이용한 상악 전치부의 수복

Successful implants should fulfill both functional and esthetic needs of patients. Especially on maxillary anterior region, many surgeons undergo difficult procedures because of improper quantity and quality of soft and hard tissue. To overcome these problems, regenerative procedures such as guided bone regeneration(GBR) and ridge spreading are often used. In this study, 2 implants were installed on maxillary anterior region using ridge spreading and GBR procedure. Before implantation, osteotomes were used to spread and compact alveolar bone. After insertion of implants, allograft and alloplast were grafted on buccal concavity, and surgical site were closed using non-resorbable membrane. There were no complications during surgery and the result was satisfyingope

Maxillary Sinus Augmentation Using Biphasic Calcium Phosphate: Dimensional Stability Results After 3-6 Years

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 (P=0.021) and a long healing period (P=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.ope

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

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 (P=0.000 and P=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 (P=0.040, P=0.000, and P=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.ope

토끼 두개골 모델에서 탈회동종골, 탈회우골, 및 합성 Hydroxyapatite의 골재생 비교연구

The purpose of this study was to compare bone regenerative effects of allograft, xenograft, and alloplast bone substitutes in rabbit calvarial defects. 14 male New Zealand rabbits were used. Four defects with a diameter of 8 mm were created on each animal. Demineralized bone matrix (DBM) gel, bovine bone (BB) and hydroxyapatite (HA) were used as the three test groups, while the control group was left unfilled. The animals were sacrificed after 2 and 8 weeks of healing. All experimental groups at 8 weeks showed statistically significant differences in new bone formation compared 2 weeks. Residual biomaterials in sites received DBM gel decreased compared to the sites received BB and HA. Within the limits of this study, there were no significant differences in bone regeneration between the sites received DBM gel, BB, and HA.ope

Association of periodontitis with menopause and hormone replacement therapy: a hospital cohort study using a common data model

Purpose: The present study was designed to compare the incidence of periodontitis according to menopausal status and to investigate the possible effect of hormone replacement therapy (HRT) on periodontitis in postmenopausal women using a common data model (CDM) at a single institution. Methods: This study involved retrospective cohort data of 950,751 patients from a 20-year database (2001 to 2020) of Ewha Womans University Mokdong Hospital converted to the Observational Medical Outcomes Partnership CDM. One-way analysis of variance models and the χ² test were used to analyze the statistical differences in patient characteristics among groups. A time-dependent Cox regression analysis was used to calculate hazard ratios and 95% confidence intervals, and P values less than 0.05 were considered to indicate statistical significance. Results: Of the 29,729 patients, 1,307 patients were diagnosed with periodontitis and 28,422 patients were not. Periodontitis was significantly more common among postmenopausal patients regardless of HRT status than among the non-menopausal group (P<0.05). Time-dependent Cox regression analysis showed that the postmenopausal patients had a significantly higher chance of having periodontitis than non-menopausal patients (P<0.05), but after adjustment for age, body mass index, and smoking status, the difference between the non-menopausal and post-menopausal HRT-treated groups was insignificant (P=0.140). Conclusions: Postmenopausal women had a significantly greater risk of periodontitis than non-menopausal women. Additionally, the use of HRT in postmenopausal women could reduce the incidence of periodontitis.ope

Diagnosis and prediction of periodontally compromised teeth using a deep learning-based convolutional neural network algorithm

Purpose: The aim of the current study was to develop a computer-assisted detection system based on a deep convolutional neural network (CNN) algorithm and to evaluate the potential usefulness and accuracy of this system for the diagnosis and prediction of periodontally compromised teeth (PCT). Methods: Combining pretrained deep CNN architecture and a self-trained network, periapical radiographic images were used to determine the optimal CNN algorithm and weights. The diagnostic and predictive accuracy, sensitivity, specificity, positive predictive value, negative predictive value, receiver operating characteristic (ROC) curve, area under the ROC curve, confusion matrix, and 95% confidence intervals (CIs) were calculated using our deep CNN algorithm, based on a Keras framework in Python. Results: The periapical radiographic dataset was split into training (n=1,044), validation (n=348), and test (n=348) datasets. With the deep learning algorithm, the diagnostic accuracy for PCT was 81.0% for premolars and 76.7% for molars. Using 64 premolars and 64 molars that were clinically diagnosed as severe PCT, the accuracy of predicting extraction was 82.8% (95% CI, 70.1%-91.2%) for premolars and 73.4% (95% CI, 59.9%-84.0%) for molars. Conclusions: We demonstrated that the deep CNN algorithm was useful for assessing the diagnosis and predictability of PCT. Therefore, with further optimization of the PCT dataset and improvements in the algorithm, a computer-aided detection system can be expected to become an effective and efficient method of diagnosing and predicting PCT.ope

Dimensional Changes in Extraction Sockets: A Pilot Study Evaluating Differences between Digital and Conventional Impressions

Traditionally, soft tissue records are obtained by dental impression using impression materials; however, accurately recording the soft tissue immediately after tooth extraction is difficult. We measured the tissue changes after tooth extraction and compared two impression modalities (digital versus conventional) by measuring the changes at the soft tissue level. In this case, 15 patients with 17 single extraction sites were enrolled. Conventional impression (CI) using vinyl polysiloxane material and digital impression (DI) using an intraoral scanner were prepared immediately after extraction (T0) and at 2 months post-extraction (T1). Standard tessellation language files were generated for superimposition of the tissue surface. The tissue changes and discrepancies were measured on the superimposed surfaces. The differences in the changes and the discrepancy between the tissue surface impression at each time point were compared. At all measuring levels, the total tissue change was significantly different between groups DI and CI (p < 0.05). DI exhibited a more pronounced tissue surface at both time points, and the total discrepancy was statistically significantly greater at T0 than at T1 (p < 0.05). The values from DI and CI demonstrated small but significantly different for the same study material. The interpretation of such differences may depend on the clinical situation or scientific value.ope

심한 골흡수가 진행된 상악에서의 상악동 거상술을 동반한 임프란트 동시 식립

The sinus floor elevation procedure has been used to be one of the predictable treatments for rehabilitation of atrophic and pneumatized edentulous posterior maxilla. Sinus elevation with simultaneous implant placement could be an optimal procedure due to reduction in surgical procedures and to patient’s convenience. This study reports the successful results of sinus elevation with the sand blasted, large grit, acid-etched (SLA) surfaced implant(ITI dental imiplant system, StraumannⓇ, Basel, Switzerland) placement simultaneously. In the first case, the height of residual ridge was 2~4mm. Autogeneous bone from ramus and alloplast(Macroporous biphasic calcium phosphate-MBCP, BiomatlanteⓇ Sarl, Nantes, France) were applied after sinus elevation through lateral window approach. SLA surfaced implants(ITI) were installed simultaneously. Result after 17 months was showed successfully. In the second case, the height of residual ridge was 3~5mm. Allograft(Freeze dried bone allograft-FDBA, Oragraft, Lifenet health, Virginia Beach, VA, USA) and alloplast(MBCP) were used for sinus graft. All procedures were followed as in the first case. Result after 9 months was showed successfully. In conclusion, this study presented successful results, when sinus elevation through window approach with mixed graft material was performed with simultaneous SLA surfaced implant placement on severe atrophied maxillary alveolar ridge, minimizing patient discomfort.ope

Effect of laser-dimpled titanium surfaces on attachment of epithelial-like cells and fibroblasts

PURPOSE: The objective of this study was to conduct an in vitro comparative evaluation of polished and laserdimpled titanium (Ti) surfaces to determine whether either surface has an advantage in promoting the attachment of epithelial-like cells and fibroblast to Ti. MATERIALS AND METHODS: Forty-eight coin-shaped samples of commercially pure, grade 4 Ti plates were used in this study. These discs were cleaned to a surface roughness (Ra: roughness centerline average) of 180 nm by polishing and were divided into three groups: SM (n=16) had no dimples and served as the control, SM15 (n=16) had 5-µm dimples at 10-µm intervals, and SM30 (n=16) had 5-µm dimples at 25-µm intervals in a 2 × 4 mm(2) area at the center of the disc. Human gingival squamous cell carcinoma cells (YD-38) and human lung fibroblasts (MRC-5) were cultured and used in cell proliferation assays, adhesion assays, immunofluorescent staining of adhesion proteins, and morphological analysis by SEM. The data were analyzed statistically to determine the significance of differences. RESULTS: The adhesion strength of epithelial cells was higher on Ti surfaces with 5-µm laser dimples than on polished Ti surfaces, while the adhesion of fibroblasts was not significantly changed by laser treatment of implant surfaces. However, epithelial cells and fibroblasts around the laser dimples appeared larger and showed increased expression of adhesion proteins. CONCLUSION: These findings demonstrate that laser dimpling may contribute to improving the periimplant soft tissue barrier. This study provided helpful information for developing the transmucosal surface of the abutment.ope