Efficacy of Oral Appliance Therapy as a First-Line Treatment for Moderate or Severe Obstructive Sleep Apnea: A Korean Prospective Multicenter Observational Study

Background@#and PurposeResponses to oral appliances (OAs) in obstructive sleep apnea (OSA) vary, and have not been fully evaluated in Korean patients. In this study we aimed to determine the efficacy of OAs for the first-line treatment of Korean patients with moderate or severe OSA. @*Methods@#This multicenter prospective observational study included 45 patients with moderate or severe OSA that had been newly diagnosed between March 2017 and May 2018 and who underwent OA treatment for 1 month. Questionnaires were completed and polysomnography (PSG) was performed before and after OA treatment. The primary outcome measures were improvement in the absolute apnea-hypopnea index (AHI) and the percentage reduction in the AHI. The secondary outcomes were improvements in the questionnaire scores related to sleep-associated symptoms and PSG parameters. @*Results@#The patients were aged 47.4±12.1 years (mean±SD), only two of them were female, and their AHI at baseline was 29.7±10.9/h. After OA treatment the AHI had reduced by 63.9±25.8%, with the reduction was similar between the patients with moderate OSA and those with severe OSA. Overall 31.1% of the patients achieved a normal AHI (<5/h), and 64.4% had an AHI of ≤10/h after the treatment. The body mass index (BMI) was the most reliable factor for predicting the percentage reduction in the AHI. The OAs also improved the sleep architecture and subjective sleep-related symptoms. @*Conclusions@#The OAs were effective in patients with moderate or severe OSA. The OAs reduced the mean AHI to 63.9% of the baseline value, and this reduction was influenced by the BMI.

The Effect of Fibronectin-Immobilized Microgrooved Titanium Substrata on Cell Proliferation and Expression of Genes and Proteins in Human Gingival Fibroblasts

BACKGROUND: We aimed to determine the effect of fibronectin (FN)-immobilized microgrooved titanium (Ti) on human gingival fibroblast proliferation, gene expression and protein expression. METHODS: Photolithography was used to fabricate the microgrooved Ti, and amine funtionalization (silanization) was used for FN immobilization on titanium surfaces. Cell proliferation, gene expression and protein expression were analyzed, followed by multiple regression analysis for determining the influential factors on cell proliferation. RESULTS: FN-immobilized microgrooved Ti significantly enhanced the fibroblast proliferation in various timelines of culture, among which a burst of fivefold increase is induced at 96 h of culture compared to that on the control smooth Ti. We suggest a presence of the synergistic promotion effect of microgrooves and FN immobilization on fibroblast proliferation. Through a series of analyses on the expression of various genes and proteins involved in cell adhesion and proliferation, cyclin-dependent kinase 6, cyclin D1, integrin α5, oncogene c-Src, osteonectin, paxillin and talin-2 were determined as influential factors on promoting fibroblast proliferation induced by FN-immobilized microgrooved Ti. CONCLUSION: FN-immobilized microgrooved Ti can act as an effective surface for enhancing fibroblast proliferation, and can be used for promoting soft tissue response on the connective tissue attachment zone of biomaterial surfaces.

A case of removable dentures using digital method / 대한치과보철학회지

Generally dentures are manufactured by conventional method, however the frequency of fabricating denture using digital method is increasing due to the recent development of digital technology in dentistry. The digital method of manufacturing denture is classified into two systems; 3D scan of the impression to arrange the artificial teeth on the CAD (Computer-aided design) and 3D printing to produce the resin-based complete denture, or 3D scan of the model to design of the framework using CAD, resin pattern formation by 3D printing and casting of metal framework of complete denture or removable partial denture. In this case report, electronic surveying and design the metal framework of the dentures were performed using CAD program, and plastic resin patterns fabricated by 3D printing were casted for upper full denture and lower removable partial denture. During follow-up periods, dentures using digital method have provided satisfactory results esthetically and functionally.

Denture wearers' recognition for their oral health status, denture cleansing methods, and insurance health system / 대한치과보철학회지

PURPOSE: The aim of the present investigation was to understand the incidence, prevalence of denture stomatitis in denture wearers, who were over 60 years old, and use the results for a fundamental data to promote public awareness about denture stomatitis and its education tools. MATERIALS AND METHODS: From August 21 to September 8 2017, 500 denture wearers, who were more than 60 years old in Seoul and 4 other metropolitan cities (Busan, Daegu, Gwangju, and Daejeon), received questionnaires. The questionnaires included denture wearers' demographic distributions, specific dental treatment experiences, discomforts with current dentures, their oral health conditions, and the method of denture cleansing. RESULTS: Thirty-two percent of 500 denture wearers responded that they have healthy oral conditions. Two hundred and eight respondents (41.6%) were aware of denture stomatitis. Only 131 (26.2%) were informed about the removable denture covered by national health insurance and 327 (65.4%) of denture wearers were using the improper denture cleansing methods. CONCLUSION: A large number of denture wearers still do not recognize the importance of proper treatment for denture stomatitis, insurance covered denture treatments, and adequate denture cleansing methods.

Implant supported removable dental prosthesis with magnetic attachment in crossed occlusion: A case report / 대한치과보철학회지

When attempting to restore the oral function of a partially edentulous patient, there are a number of prosthetic treatment options available, depending on the structure of remaining teeth. For example, when only one set of maxillary and mandibular teeth are diagonally in place across from each other, it is difficult to gain stable occlusion. In this case, implants can be put in place at the corresponding edentulous area to achieve balance. By doing so, a stable occlusion can be achieved. For this case report, a patient with crossed occlusion after extraction was treated with maxillary RDP (removable dental prosthesis) and mandibular implant-supported RDP (removable dental prosthesis). Moreover, an implant fixture was placed under the posterior molar of the distal extension base diagonally across from the remaining maxillary teeth. Then, magnetic attachment was implemented. According to the patient who received the treatment, the result was functionally and aesthetically satisfactory.

A new retaining method of cement-retained restoration with linguo-horizontal insertion of fiber post / 대한치과보철학회지

The retaining methods of implant prosthesis were classified into a screw-retained and a cement-retained type. A screw-retained prosthesis has many advantages, such as retrievability, preventing residual cement, while their disadvantages include the possibility of screw loosening and fracture, on the contrary advantages of cement-retained prosthesis are relatively low cost, but they are difficult to retrieve. To combine the advantages of both type, screw-cement retained prosthesis (SCRP) type have been introduced. But they still require ideal implant placement. So we introduce fiber post retained prosthesis without residual cement for preventing soft tissue trouble due to excessive cement.

Analysis of dimensions and shapes of maxillary and mandibular dental arch in Korean young adults

PURPOSE: The aim of this study was to investigate dental arch dimensions and to classify arch shape in Korean young adults. MATERIALS AND METHODS: The sample included 50 Koreans with age ranging from 24 to 32 years. Maxillary and mandibular casts were fabricated using irreversible hydrocolloid and type III dental stones. Incisor-canine distance, incisor-1(st) molar distance, incisor-2(nd) molar distance, intercanine distance, inter-1(st) molar distance, and inter-2(nd) molar distance in both the maxillary and mandibular arch were measured using a three-dimensional measuring device. The dental arch was classified into three groups using five ratios from the measured values by the K-means clustering method. The data were analyzed with one-way analysis of variance. RESULTS: Arch lengths (IM2D, incisal-2(nd) molar distance) were 44.13 mm in the maxilla and 40.40 mm in the mandible. Arch widths (M2W, inter 2(nd) molar width) were 64.12 mm in the maxilla and 56.37 mm in the mandible. Distribution of the dental arch form was mostly ovoid shape (maxilla 52% and mandible 56%), followed by the V-shape and the U-shape. The arch width for the U-shape was broader than for the other forms. CONCLUSION: This study establishes new reference data for dental arch dimensions for young Korean adults. The most common arch form is the ovoid type in the maxilla and mandible of Koreans. Clinicians should be aware of these references and classify arch type before and during their dental treatment for effective and harmonized results in Koreans.

Static magnetic fields promote osteoblastic/cementoblastic differentiation in osteoblasts, cementoblasts, and periodontal ligament cells

PURPOSE: Although static magnetic fields (SMFs) have been used in dental prostheses and osseointegrated implants, their biological effects on osteoblastic and cementoblastic differentiation in cells involved in periodontal regeneration remain unknown. This study was undertaken to investigate the effects of SMFs (15 mT) on the osteoblastic and cementoblastic differentiation of human osteoblasts, periodontal ligament cells (PDLCs), and cementoblasts, and to explore the possible mechanisms underlying these effects. METHODS: Differentiation was evaluated by measuring alkaline phosphatase (ALP) activity, mineralized nodule formation based on Alizarin red staining, calcium content, and the expression of marker mRNAs assessed by reverse transcription polymerase chain reaction (RT-PCR). Signaling pathways were analyzed by western blotting and immunocytochemistry. RESULTS: The activities of the early marker ALP and the late markers matrix mineralization and calcium content, as well as osteoblast- and cementoblast-specific gene expression in osteoblasts, PDLCs, and cementoblasts were enhanced. SMFs upregulated the expression of Wnt proteins, and increased the phosphorylation of glycogen synthase kinase-3β (GSK-3β) and total β-catenin protein expression. Furthermore, p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK), and nuclear factor-κB (NF-κB) pathways were activated. CONCLUSIONS: SMF treatment enhanced osteoblastic and/or cementoblastic differentiation in osteoblasts, cementoblasts, and PDLCs. These findings provide a molecular basis for the beneficial osteogenic and/or cementogenic effect of SMFs, which could have potential in stimulating bone or cementum formation during bone regeneration and in patients with periodontal disease.

Regulation of human gingival fibroblast gene expression on microgrooves: A DNA microarray study / 대한치과보철학회지

PURPOSE: We aimed to investigate the gene expression of human gingival fibroblasts on microgroove surface using DNA microarray. MATERIALS AND METHODS: Microgrooves were applied on grade II titanium discs to have 0/0 µm (NE0, control group), 60/10 µm (E60/10, experimental group) of respective width/depth by photolithography. The entire surface of the microgrooved Ti substrata was further acid etched and used as the two experimental groups in this study. Human gingival fibroblasts were cultured in the experimental group and the control group, and total RNA was extracted. The oligonucleotide microarray was performed to confirm the changes of various gene expression levels between experimental group and control group. Changes of gene expression level were determined at the pathway level by mapping the expression results of DNA chips, using the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis. RESULTS: Gene expression levels on E60/10 and NE0 were analyzed, there were 123 genes showing significant differences in expression more than 1.5 times on E60/10 microgrooved surface compared to NE0 surface, and 19 genes showing significant differences in expression more than 2 times. The KEGG pathway analysis confirmed the changes in gene expression levels under experimental conditions. Cell signaling, proliferation, and activity among the various gene expression results were identified. CONCLUSION: Microgrooved surfaces induce gene expression changes and related cell signaling. According to the results of this study, microgrooves can be used as the surface of various biomaterials which need to improve cell activity through gene expression changes and activation of cell signaling.

CAD/CAM fabricated complete denture using 3D face scan: A case report / 대한치과보철학회지

In the past, computer-aided design/computer-aided manufacturing (CAD/CAM) technology was the closed system that users had to use the components of only one manufacturer. At present, it has changed to the open system with the flexibility to select and use the components of various manufacturers' components according to their needs. Despite the development of dental materials and prostheses manufacturing methods, denture manufacturing has followed conventional manufacturing methods for nearly 100 years. However, studies on CAD/CAM fabricated denture have been recently carried out to overcome the disadvantages of conventional denture manufacturing. Some commercialized products using milling or 3D printing have already been applied clinically. This case report confirms the possibility of CAD/CAM dentures using 3D face scan and compared them to conventionally fabricated dentures.

Analysis of crown size and morphology, and gingival shape in the maxillary anterior dentition in Korean young adults

PURPOSE: The aim of this investigation was to analyze the dimensions of clinical crowns and to classify the crown and the gingival type in the anterior teeth in Korean young adults. MATERIALS AND METHODS: Casts were obtained from 50 subjects ranging in age from 24 to 32. Measurements of length and width were made on the casts using a pair of digital calipers on the entire dentition. Crown thickness and papilla height were also measured and MDW/CL (mesiodistal width to clinical length) and CW/CL (cervical width to clinical length) ratios of the maxillary anterior teeth were calculated. The K-clustering method was used for CW/CL to classify the anterior tooth shape into three groups (tapered, ovoid, and square), and one-way analysis of variance and Duncan's post-hoc comparison were used to evaluate statistical significance between the groups. Pearson's correlation analysis was performed between tooth shape and papillary height (PH) to demonstrate the correlation between tooth shape and gingival morphological characteristics. RESULTS: The average length of the maxillary central incisors was 9.89 mm; the mesio-distal width was 8.54 mm; and the ratio of width/length was 0.86 in Korean young adults. The average bucco-palatal thickness of the central incisor was 3.14 mm at the incisal 1/3 aspect. Ovoid type was the most common tooth shape (48%), followed by square type (29%) and taper type (23%) in the central incisors of Korean young adults. Tooth shape and gingival type were correlated with each other. CONCLUSION: New reference data were established for tooth size in Korean young adults and the data show several patterns of tooth shape and gingival type. Clinicians should diagnose and treat based on these characteristics for better results in the Korean population.

Primary implant stability in a bone model simulating clinical situations for the posterior maxilla: an in vitro study

PURPOSE: The aim of this study was to determine the influence of anatomical conditions on primary stability in the models simulating posterior maxilla. METHODS: Polyurethane blocks were designed to simulate monocortical (M) and bicortical (B) conditions. Each condition had four subgroups measuring 3 mm (M3, B3), 5 mm (M5, B5), 8 mm (M8, B8), and 12 mm (M12, B12) in residual bone height (RBH). After implant placement, the implant stability quotient (ISQ), Periotest value (PTV), insertion torque (IT), and reverse torque (RT) were measured. Two-factor ANOVA (two cortical conditions×four RBHs) and additional analyses for simple main effects were performed. RESULTS: A significant interaction between cortical condition and RBH was demonstrated for all methods measuring stability with two-factor ANOVA. In the analyses for simple main effects, ISQ and PTV were statistically higher in the bicortical groups than the corresponding monocortical groups, respectively. In the monocortical group, ISQ and PTV showed a statistically significant rise with increasing RBH. Measurements of IT and RT showed a similar tendency, measuring highest in the M3 group, followed by the M8, the M5, and the M12 groups. In the bicortical group, all variables showed a similar tendency, with different degrees of rise and decline. The B8 group showed the highest values, followed by the B12, the B5, and the B3 groups. The highest coefficient was demonstrated between ISQ and PTV. CONCLUSIONS: Primary stability was enhanced by the presence of bicortex and increased RBH, which may be better demonstrated by ISQ and PTV than by IT and RT.

Influence of the connection design and titanium grades of the implant complex on resistance under static loading

PURPOSE: The purpose of this study was to evaluate the resistance to deformation under static overloading by measuring yield and fracture strength, and to analyze the failure characteristics of implant assemblies made of different titanium grades and connections. MATERIALS AND METHODS: Six groups of implant assemblies were fabricated according to ISO 14801 (n=10). These consisted of the combinations of 3 platform connections (external, internal, and morse tapered) and 2 materials (titanium grade 2 and titanium grade 4). Yield strength and fracture strength were evaluated with a computer-controlled Universal Testing Machine, and failed implant assemblies were classified and analyzed by optical microscopy. The data were analyzed using the One-way analysis of variance (ANOVA) and Student's t-test with the level of significance at P=.05. RESULTS: The group IT4S had the significantly highest values and group IT2 the lowest, for both yield strength and fracture strength. Groups IT4N and ET4 had similar yield and fracture strengths despite having different connection designs. Group MT2 and group IT2 had significant differences in yield and fracture strength although they were made by the same material as titanium grade 2. The implant system of the similar fixture-abutment interfaces and the same materials showed the similar characteristics of deformation. CONCLUSION: A longer internal connection and titanium grade 4 of the implant system is advantageous for static overloading condition. However, it is not only the connection design that affects the stability. The strength of the titanium grade as material is also important since it affects the implant stability. When using the implant system made of titanium grade 2, a larger diameter fixture should be selected in order to provide enough strength to withstand overloading.

Effect of titanium surface microgrooves and thermal oxidation on in vitro osteoblast responses / 대한치과보철학회지

PURPOSE: We aimed to investigate the effect of combined various microgrooves and thermal oxidation on the titanium (Ti) and to evaluate various in vitro responses of human periodontal ligament cells (PLCs). MATERIALS AND METHODS: Grade II titanium disks were fabricated. Microgrooves were applied on titanium discs to have 0/0 microm, 15/3.5 microm, 30/10 microm, and 60/10 microm of respective width/depth by photolithography. Thermal oxidation was performed on the microgrooves of Ti substrata for 3 h at 700degrees C in air. The experiments were divided into 3 groups: control group (ST), thermal oxidation group (ST/TO), and combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO). Surface characterization was performed by field-emission scanning microscopy. Cell adhesion, osteoblastic differentiation, and mineralization were analyzed using the bromodeoxyurdine (BrdU), Alkaline phosphatase (ALP) activity, and extracellular calcium deposition assays, respectively. Statistical analysis was performed using the oneway analysis of variance and Pearson's bivariate correlation analysis (SPSS Version 17.0). RESULTS: In general, the combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO) showed significantly higher levels compared with the control (ST) or thermal oxidation (ST-TO) groups in the BrdU expression, ALP activity, and extracellular calcium deposition. Gr60-TO group induced highest levels of cell adhesion and osteoblastic differentiation. CONCLUSION: Within the limitation of this study, we conclude that the Ti surface treatment using combined microgrooves and thermal oxidation is highly effective in inducing the cell adhesion andosteoblastic differentiation. The propose surface is also expected to be effective in inducing rapid and strong osseointegration of Ti oral implants.

The effect of IDS (immediate dentin sealing) on dentin bond strength under various thermocycling periods

PURPOSE: The purpose of this study was to find out the effect of immediate dentin sealing (IDS) on bond strength of ceramic restoration under various thermocycling periods with DBA (dentin bonding agent system). MATERIALS AND METHODS: Fifty freshly extracted human mandibular third molars were divided into 5 groups (1 control and 4 experimental groups) of 10 teeth. We removed enamel layer of sound teeth and embedded them which will proceed to be IDS, using All Bond II. A thermocycling was applied to experimental groups for 1, 2, 7, 14 days respectively and was not applied to control group. IPS Empress II for ceramic was acid-etched with ceramic etchant (9.5% HF) and silane was applied. Each ceramic disc was bonded to specimens with Duo-link, dual curable resin cement by means of light curing for 100 seconds. After the cementation procedures, shear bond strength measurement and SEM analysis of the fractured surface were done. The data were analyzed with a one-way ANOVA and Tukey multiple comparison test (alpha=.05). RESULTS: There were no statistically significant differences between 4 experimental groups and control group, however the mean value started to decrease in group 7d, and group 14d showed the lowest mean bond strength in all groups. Also, group 7d and 14d showed distinct exposed dentin and collapsed hybrid layer was observed in SEM analysis. CONCLUSION: In the present study, it can be concluded that ceramic restorations like a laminate veneer restoration should be bonded using resin cement within one week after IDS procedure.

Effect of microgrooves and fibronectin conjugation on the osteoblast marker gene expression and differentiation

PURPOSE: To determine the effect of fibronectin (FN)-conjugated, microgrooved titanium (Ti) on osteoblast differentiation and gene expression in human bone marrow-derived mesenchymal stem cells (MSCs). MATERIALS AND METHODS: Photolithography was used to fabricate the microgrooved Ti, and amine functionalization (silanization) was used to immobilize fibronectin on the titanium surfaces. Osteoblast differentiation and osteoblast marker gene expression were analyzed by means of alkaline phosphatase activity assay, extracellular calcium deposition assay, and quantitative real-time PCR. RESULTS: The conjugation of fibronectin on Ti significantly increased osteoblast differentiation in MSCs compared with non-conjugated Ti substrates. On the extracellular calcium deposition assays of MSCs at 21 days, an approximately two-fold increase in calcium concentration was observed on the etched 60-microm-wide/10-microm-deep microgrooved surface with fibronectin (E60/10FN) compared with the same surface without fibronectin (E60/10), and a more than four-fold increase in calcium concentration was observed on E60/10FN compared with the non-etched control (NE0) and etched control (E0) surfaces. Through a series of analyses to determine the expression of osteoblast marker genes, a significant increase in all the marker genes except type I collagen alpha1 mRNA was seen with E60/10FN more than with any of the other groups, as compared with NE0. CONCLUSION: The FN-conjugated, microgrooved Ti substrate can provide an effective surface to promote osteoblast differentiation and osteoblast marker gene expression in MSCs.

Effect of etched microgrooves on hydrophilicity of titanium and osteoblast responses: A pilot study

PURPOSE: The aim of this pilot study was to investigate the effect of etched microgrooves on the hydrophilicity of Ti and osteoblast responses. MATERIAL AND METHODS: Microgrooves were applied on Ti to have 15 and 60 micrometer width, and 3.5 and 10 micrometer depth by photolithography, respectively. Further acid etching was applied to create Ti surfaces with etched microgrooves. Both smooth- and acid-etched Ti were used as the controls. The hydrophilicity of Ti was analyzed by determining contact angles. Cell proliferation and osteogenic activity of MC3T3 mouse preosteoblasts were analyzed by bromodeoxyuridine assay and alkaline phosphatase (ALP) activity test, respectively. One-way ANOVA, Pearson's correlation analysis and multiple regression analysis were used for statistics. RESULTS: Etched microgrooves significantly increased the hydrophilicity of Ti compared to the smooth Ti. 60 micrometer-wide etched microgrooves significantly enhanced cell proliferation, whereas the osteogenic activity showed statistically non-significant differences between groups. Result of the osteogenic activity significantly correlated with those of hydrophilicity and cell proliferation. Hydrophilicity was determined to be an influential factor on osteogenic activity. CONCLUSION: This study indicates that increase in hydrophilicity of Ti caused by etched microgrooves acts as an influential factor on osteogenic activity. However, statistically non-significant increase in the ALP activity suggests further investigation.