Analysis of Relationship between Electroencephalograms and Subjective Measurements for In-Vehicle Information System: A Preliminary Study.

In this study, we explored the relationship between objective and subjective measures for usability evaluation in in-vehicle infotainment systems (IVISs). As a case study, four displays were evaluated based on cluster location and display orientation (that is, front-horizontal, front-vertical, right-horizontal, and right-vertical). Thirty-six participants performed tasks to manipulate the functions of the IVISs and data were collected through an electroencephalogram (EEG) sensor and questionnaire items. We analysed a model that estimated EEG-based objective indicators from subjective indicators. As a result, the objective indicators reflected the subjective indicators and were considered to explain the driver's cognitive state. Although EEG data were collected from only four participants, this study proposed an experimental design that could be applied to the analysis of the relationship between the subject's evaluation and EEG signals, as a preliminary study. We expect the experimental design and results of this study to be useful in analysing objective and subjective measures of usability evaluation.

Innovative digital tools for new trends in teaching and assessment methods in medical and dental education.

With the goal of providing optimal care to patients, student-centered active learning and the development of clinical competency have become vital components of the education of future physicians capable of sustainably coping with future challenges. However, the shape of future medicine is dramatically changing based on advances in information and communication technology, and the current classroom model seems to have difficulties in fully preparing students for the future of medicine. New trends in teaching and assessment methods include computer-aided instruction, virtual patients, augmented reality, human patient simulations, and virtual reality for the assessment of students' competency. The digital technologies introduced in medical and dental education include Google Forms to collect students' answers, YouTube livestreaming, google art & culture (an online art museum), and choose-your-own-adventure as a story-telling technique. Innovations in digital technology will lead the way toward a revolution in medical and dental education, allowing learning to be individualized, interactive, and efficient.

Digital Assessment of Gingival Dimensions of Healthy Periodontium.

The aim of the present study was to re-visit the gingival dimension using digital scanning in a healthy Korean population. Forty-eight periodontally healthy volunteers (38 males and 10 females, mean age: 24.3 ± 2.2 years) were included. The mucogingival junction was highlighted using 2.5% diluted iodine solution. Then, the facial gingiva and mucosa of both jaws were digitally scanned using an intraoral digital scanner. Using computer software and periodontal probing, the heights and areas of keratinized gingiva (KG) and attached gingiva (AG) were measured. Similar distribution patterns in the gingival heights were noted in the maxilla and mandible. The maxilla showed substantially greater gingival values than the mandible. The heights of the KG and AG were notably smaller on the mandibular first premolar (2.37 mm and 1.07 mm, median value) and second molar (3.28 mm and 1.78 mm) than on the other teeth. The area of the KG was the largest in the canine (63.74 mm2 and 46.85 mm2) and first molar (64.14 mm2 and 58.82 mm2) in each jaw. Mandibular first and second molars, mandibular canine, and maxillary canine showed the highest value of the area under the receiver operation characteristics curve (>0.7) for differentiating between males and females. The gingival dimensions recorded using intraoral scanner demonstrated similar distribution patterns as in previous studies.

Video learning strategies affecting achievement, learning approach, and lifelong learning in a flipped periodontology course.

OBJECTIVE: To explore how video learning strategies influence students' Flipped learning (FL) achievement, deep approach to learning (DAL) and lifelong learning (LL) orientations and how DAL and LL can be promoted. METHODS: Data were collected from 65 dental students enrolled in a 21-week clinical periodontology course. Partial least squares structural equation modeling was conducted to investigate factors and pathways affecting FL achievement, DAL, and LL. RESULTS: FL achievement was predicted by repeated and in-advance video learning strategies. In-advance, meticulous, and expanded video learning strategies directly influenced DAL, and indirectly influenced LL via DAL. LL was not affected by any of the video learning strategies but by the DAL. CONCLUSION: This study implies that mere implementation of FL may not guarantee more developed DAL and enhanced LL. Redesigning a course with FL should entail revisiting and revising student assessment. LL is an inclusive approach that requires the long-term cultivation of meaning, experience, insight, learning, and practice.

A case series of profilometric changes in two implant placement protocols at periodontally compromised non-molar sites.

Information regarding profilometric changes at a soft tissue level following implant placement with different protocols is insufficient. Therefore, this study aimed to comparatively investigate the profilometric tissue changes with respect to late implant placement following alveolar ridge preservation (LP/ARP) and early implantation (EP) in periodontally compromised non-molar extraction sites. Sixteen patients were randomly assigned to the following groups: implant placement 4 months post-ARP (group LP/ARP) and tooth extraction and implant placement 4-8 weeks post-extraction (group EP). Dental impressions were obtained immediately after final prosthesis insertion and at 3, 6, and 12 months. At the time of implant placement, bone augmentation was performed in the majority of the patients. Profilometric changes of the tissue contour were minimal between the final prosthesis insertion and 12 months in the mid-facial area (0.04-0.35 mm in group LP/ARP, 0.04-0.19 mm in group EP). The overall tissue volume increased in both groups (1.70 mm3 in group LP/ARP, 0.96 mm3 in group EP). In conclusion, LP/ARP and EP led to similar stability of the peri-implant tissue contour between the final prosthesis insertion and at 12 months. Moreover, the change of peri-implant tissue on the soft tissue level was minimal in both modalities.

Histological comparison of different compressive forces on particulate grafts during alveolar ridge preservation: a prospective proof-of-concept study.

PURPOSE: The aim of this study was to determine the impact of different compressive forces on deproteinized bovine bone mineral (DBBM) particles covered by native bilayer collagen membrane (NBCM) during alveolar ridge preservation (ARP) in the molar area, and to identify any histomorphometric and clinical differences according to the compressive force applied. METHODS: Sockets were filled with DBBM after tooth extraction, and different compressive forces (30 N and 5 N, respectively) were applied to the graft material in the test (30 N) and control (5 N) groups. The DBBM in both groups was covered with NBCM in a double-layered fashion. A crossed horizontal mattress suture (hidden X) was then made. A core biopsy was performed using a trephine bur without flap elevation at the implant placement site for histomorphometric evaluations after 4 months. The change of the marginal bone level was measured using radiography. RESULTS: Twelve patients completed the study. The histomorphometric analysis demonstrated that the mean ratios of the areas of new bone, residual graft material, and soft tissue and the implant stability quotient did not differ significantly between the groups (P>0.05). However, the mean size of the residual graft material showed a significant intergroup difference (P<0.05). CONCLUSIONS: The application of 2 compressive forces (5 N, 30 N) on particulate DBBM grafts during open-healing ARP in the posterior area led to comparable new bone formation, implant feasibility and peri-implant bone level.

Highly Luminous Ba2SiO4-δN2/3δ:Eu2+ Phosphor for NUV-LEDs: Origin of PL-Enhancement by N3--Substitution.

Ba2SiO4-δN2/3δ:Eu2+ (BSON:Eu2+) materials with different N3- contents were successfully prepared and characterized. Rietveld refinements showed that N3- ions were partially substituted for the O2- ions in the SiO4-tetrahedra because the bond lengths of Si‒(O,N) (average value = 1.689 Å) were slightly elongated compared with those of Si‒O (average value = 1.659 Å), which resulted in the minute compression of the Ba(2)‒O bond lengths from 2.832 to 2.810 Å. The average N3- contents of BSON:Eu2+ phosphors were determined from 100 nm to 2000 nm depth of grain using a secondary ion mass spectrometry (SIMS): 0.064 (synthesized using 100% α-Si3N4), 0.035 (using 50% α-Si3N4 and 50% SiO2), and 0.000 (using 100% SiO2). Infrared (IR) and X-ray photoelectron spectroscopy (XPS) measurements corroborated the Rietveld refinements: the new IR mode at 850 cm-1 (Si‒N stretching vibration) and the binding energy at 98.6 eV (Si-2p) due to the N3- substitution. Furthermore, in UV-region, the absorbance of N3--substituted BSON:Eu2+ (synthesized using 100% α-Si3N4) phosphor was about two times higher than that of BSO:Eu2+ (using 100% SiO2). Owing to the N3- substitution, surprisingly, the photoluminescence (PL) and LED-PL intensity of BSON:Eu2+ (synthesized using 100% α-Si3N4) was about 5.0 times as high as that of BSO:Eu2+ (using 100% SiO2). The compressive strain estimated by the Williamson-Hall (W-H) method, was slightly increased with the higher N3- content in the host-lattice of Ba2SiO4, which warranted that the N3- ion plays an important role in the highly enhanced PL intensity of BSON:Eu2+ phosphor. These phosphor materials could be a bridgehead for developing new phosphors and application in white NUV-LEDs field.

Lip Repositioning Surgery Using an Er,Cr:YSGG Laser: A Case Series.

Excessive gingival display (EGD) is a common esthetic concern. Lip repositioning surgery (LRS) was introduced as one of the treatment options to manage EGD. LRS can be used for skeletally and/or muscularly induced EGD. The present case series applied LRS using an Er,Cr:YSGG laser to treat 24 patients with minor vertical maxillary overgrowth or a hypermobile lip. At 6 months, the gingival display had decreased by 3.79 ± 1.59 mm (mean ± standard deviation), and the visible lip body when smiling had increased by 1.23 ± 0.74 mm. A questionnaire revealed that the level of satisfaction with the smile increased among the patients and that they had a positive attitude toward Er,Cr:YSGG laser-assisted LRS.

Nutrient intakes and medication use in elderly individuals with and without dry mouths.

BACKGROUND/OBJECTIVES: The nutrition of the elderly depends on various factors. Oral health, especially oral dryness, can be an important risk factor. In this study, we attempted to determine whether dry mouth is associated with compromised nutrient intakes. SUBJECTS/METHODS: A total of 120 participants aged 65-86 yrs (mean age: 69 ± 1 y) were included in this study. Demographic and health-related characteristics, living status, meals, number of medications, medical conditions, chewing ability, and quality of life, the Oral Health Impact Profile (the OHIP-14) were assessed. We performed one day 24-hr recall assessment for nutrient analyses. The differences of the means between the dry-mouth and non-dry-mouth groups were analyzed. Elderly subjects with xerostomia-induced dry mouth were classified as those who reported at least one dryness symptom on a questionnaire. RESULTS: A significant difference in population distribution was observed among the elderly who took medications for hypertension, diabetes and osteoporosis and was significantly higher in the dry-mouth group (70.2%) than in the non-dry-mouth group (44.4%) (P = 0.005). Compared with the non-dry-mouth group (50.8%), a significantly higher proportion (73.7%) of participants in the dry-mouth group took multiple medicines (≥ 4 medications) (P = 0.019). The intakes of vegetable fat, vitamin E, folate and water in the dry-mouth group were lower than in the non-dry-mouth group. The intakes of fluoride and ω-3 fatty acids were significantly lower in the dry-mouth group than in the non-dry-mouth group. CONCLUSION: The participants in the dry-mouth group exhibited low nutrient and water intakes. It is recommended that the elderly with dry mouth should drink sufficient water and receive targeted and specific nutritional guidance to prevent malnutrition.

Late implant placement following ridge preservation versus early implant placement: A pilot randomized clinical trial for periodontally compromised non-molar extraction sites.

AIM: To compare late implant placement following alveolar ridge preservation (LP/ARP) and early implantation (EP) in periodontally compromised non-molar extraction sites with respect to soft tissue levels, aesthetics, and patient-reported outcomes. MATERIALS AND METHODS: Sixteen patients were randomly allocated to groups LP/ARP (n = 9) or EP (n = 7). Group LP/ARP received ARP using deproteinized bovine bone mineral containing 10% collagen and a native bilayer collagen membrane, and group EP received only extraction. Implant placement was performed 4-8 weeks post-extraction in group EP and 4 months post-alveolar ridge preservation in group LP/ARP. The soft tissue levels, pink/white esthetic scores, and periodontal parameters were evaluated at 1 year post-loading. Patient's discomfort level was evaluated in terms of extraction/ARP and implant placement. RESULTS: No implant failure or biologic complications occurred. There was no statistically significant difference in the median change of the midfacial mucosal margin (0.03 for group LP/ARP, -0.19 mm for group EP) and the mesial/distal papilla (0.62/0.25 mm for group LP/ARP, 0.29/-0.5 mm for group EP), pink/white esthetic scores, periodontal parameters, and patient's discomfort between the two groups. CONCLUSION: Both implant placement protocols led to comparable outcomes in soft tissue levels, periodontal parameters, and patient's discomfort level.

Early implant failure: a retrospective analysis of contributing factors.

PURPOSE: The aim of this retrospective study was to determine the prevalence of early implant failure using a single implant system and to identify the factors contributing to early implant failure. METHODS: Patients who received implant treatment with a single implant system (Luna®, Shinhung, Seoul, Korea) at Dankook University Dental Hospital from 2015 to 2017 were enrolled. The following data were collected for analysis: sex and age of the patient, seniority of the surgeon, diameter and length of the implant, position in the dental arch, access approach for sinus-floor elevation, and type of guided bone regeneration (GBR) procedure. The effect of each predictor was evaluated using the crude hazard ratio and the adjusted hazard ratio (aHR) in univariate and multivariate Cox regression analyses, respectively. RESULTS: This study analyzed 1,031 implants in 409 patients, who comprised 169 females and 240 males with a median age of 54 years (interquartile range [IQR], 47-61 years) and were followed up for a median of 7.2 months (IQR, 5.6-9.9 months) after implant placement. Thirty-five implants were removed prior to final prosthesis delivery, and the cumulative survival rate in the early phase at the implant level was 95.6%. Multivariate regression analysis revealed that seniority of the surgeon (residents: aHR=2.86; 95% confidence interval [CI], 1.37-5.94) and the jaw in which the implant was placed (mandible: aHR=2.31; 95% CI, 1.12-4.76) exerted statistically significant effects on early implant failure after adjusting for sex, age, dimensions of the implant, and type of GBR procedure (preoperative and/or simultaneous) (P<0.05). CONCLUSIONS: Prospective studies are warranted to further elucidate the factors contributing to early implant failure. In the meantime, surgeons should receive appropriate training and carefully select the bone bed in order to minimize the risk of early implant failure.

Highly Luminous N3--Substituted Li2MSiO4-δN2/3δ:Eu2+ (M = Ca, Sr, and Ba) for White NUV Light-Emitting Diodes.

The N3--substituted Li2MSiO4:Eu2+ (M = Ca, Sr, and Ba) phosphors were systematically prepared and analyzed. Secondary-ion mass spectroscopy measurements revealed that the average N3- contents are 0.003 for Ca, 0.009 for Sr, and 0.032 for Ba. Furthermore, the N3- incorporation in the host lattices was corroborated by infrared and X-ray photoelectron spectroscopies. From the photoluminescence spectra of Li2MSiO4:Eu2+ (M = Ca, Sr, and Ba) phosphors before and after N3- doping, it was verified that the enhanced emission intensity of the phosphors is most likely due to the N3- doping. In Li2MSiO4:Eu2+ (M = Ca, Sr, and Ba) phosphors, the maximum wavelengths of the emission band were red-shifted in the order Ca < Ba < Sr, which is not consistent with the trend of crystal field splitting: Ba < Sr < Ca. This discrepancy was clearly explained by electron-electron repulsions among polyhedra, LiO4-MO n , SiO4-MO n , and MO n -M'O n associated with structural difference in the host lattices. Therefore, the energy levels associated with the 4f65d energy levels of Eu2+ are definitely established in the following order: Li2CaSiO4:Eu2+ > Li2BaSiO4:Eu2+ > Li2SrSiO4:Eu2+. Furthermore, using the Williamson-Hall (W-H) method, the determined structural strains of Li2MSiO4:Eu2+ (M = Ca, Sr, and Ba) phosphors revealed that the increased compressive strain after N3- doping induces the enhanced emission intensity of these phosphors. White light-emitting diodes made by three N3--doped phosphors and a 365 nm emitting InGaN chip showed the (0.333, 0.373) color coordinate and high color-rendering index (R a = 83). These phosphor materials may provide a platform for development of new efficient phosphors in solid-state lighting field.

Ridge preservation in molar extraction sites with an open-healing approach: A randomized controlled clinical trial.

AIM: To determine the effect of alveolar ridge preservation (ARP) in molar sites without primary flap closure. MATERIALS AND METHODS: Three groups were established: extraction sockets grafted with deproteinized bovine bone mineral containing 10% collagen (DBBM-C) and covered by a native bilayer collagen membrane (NBCM) (test group 1), sockets grafted with DBBM-C only (test group 2), and sockets that healed naturally (control group). Primary flap closure was not attempted. Conebeam computed tomography scans were obtained immediately and then 4 months after ARP. A biopsy was performed. The change of the marginal bone level was measured. RESULTS: There was significantly less horizontal resorption in test group 1 than in the control group at levels 1 mm (-1.02 ± 0.88 [mean ± SD] vs. -4.44 ± 3.71 mm) and 3 mm (-0.31 ± 1.51 vs. -2.27 ± 1.15 mm) below the crest, and significantly less vertical reduction in the midcrestal area in test group 1 than in test group 2 (-0.25 ± 0.95 vs. -1.15 ± 1.63 mm) (p < .05). There were no significant differences between test groups in clinical and histomorphometric measurements. All groups exhibited stable marginal bone levels after 1 year of loading. CONCLUSION: Alveolar ridge preservation without primary flap closure in molar areas was effective in minimizing ridge resorption and facilitated implant treatment.

Graphene-coated microballs for a hyper-sensitive vacuum sensor.

Reduced graphene oxide (RGO)-coated microballs of poly (methyl methacrylate) (PMMA) used for fabricating three-dimensional sensor (3D sensor), which are expected to exhibit high sensitivity compared with conventional two-dimensional (2D) sensors, were prepared using a reaction-based assembly process. The sheet resistance and transmittance of the RGO-coated balls decreased with increasing number of coatings, implying that the RGO was well adhered to the ball by the assembly method. Two types of vacuum pressure sensors using multiple balls and a single ball were fabricated using lift-off and air-blowing methods, respectively. At pressures <1 torr, the sensors showed an increased resistance value due to the bending of graphene sheets by the Van der Waals attractive force. Further, the pressure versus resistance values at the logarithmic scale showed a linear relation, with a pressure reading error <6%. Compared with the 2D sensor fabricated using RGO, the multiball sensor exhibited almost 4-5 times higher RRC value. The single-ball sensor showed reasonable reproducibility at various temperatures. Given the size and pressure reading range of the sensor, the sensitivity of the single-ball sensor at 100 °C was approximately 6,000 times greater than that of the sensor with the highest sensitivity reported in the literature. The increase in surface area and the geometric effect of the sensing part of the single-ball sensor appeared to be responsible for its abnormally high sensitivity.

A randomized, double-blind, placebo-controlled multicenter study for evaluating the effects of fixed-dose combinations of vitamin C, vitamin E, lysozyme, and carbazochrome on gingival inflammation in chronic periodontitis patients.

BACKGROUND: To evaluate gingival inflammation from fixed-dose combinations of vitamin C, vitamin E, lysozyme and carbazochrome (CELC) in the treatment of chronic periodontitis following scaling and root planing. METHODS: One hundred patients were randomly assigned to receive CELC (test) or placebo (control) for the first 4 weeks at a 1:1 ratio, and both groups received CELC for the remaining 4 weeks. Primary outcome was the mean change in the gingival index (GI) after 4 weeks. Secondary outcomes included mean change in GI after 8 weeks and plaque index, probing depth, clinical attachment level, and VAS at 4 weeks and 8 weeks. RESULTS: Ninety-three patients completed the study. The GI in the test group significantly decreased after 4 weeks (p < 0.001) and 8 weeks (p < 0.001). The mean change from baseline in GI significantly decreased in the test group compared to the control group after 4 weeks (p = 0.015). In the GEE model adjusting for age, gender and visits, the test group showed 2.5 times GI improvement compared to the control group (p = 0.022). CONCLUSIONS: Within the study, CELC showed a significant reduction in gingival inflammation compared with a placebo. Other parameters, however, were similar between groups. TRIAL REGISTRATION: KCT0001366 (Clinical Research Information Service, Republic of Korea) and 29 Jan 2015, retrospectively registered.

Self-emitting blue and red EuOX (X = F, Cl, Br, I) materials: band structure, charge transfer energy, and emission energy.

Self-emitting blue and red EuOX (X = F, Cl, Br, and I) were successfully synthesized and characterized. Far-infrared and Raman measurements revealed that the vibration modes prominently reflected the Eu-O and Eu-X bond characters of these materials. X-ray photoelectron spectroscopy (XPS) of the red-emitting EuOX compounds showed that Eu exclusively existed as Eu3+, while in the blue-emitting EuOX, a mixed Eu3+/Eu2+ state was observed. For the red-emitting EuOX (X = F, Cl, and Br), the maximum wavelengths of the charge-transfer (CT) bands were red-shifted: F → Cl → Br (282, 320, and 330 nm for F, Cl, and Br, respectively). Using one-electron spin-polarized band structure calculations, it was verified that the red-shift of the CT energy from F to Br in EuOX was mainly due to the relative positions of the halogen orbital energies being gradually increased, following the trend in their electronegativity. For the blue-emitting EuOX (X = Cl, Br, and I), the emission band maxima were red-shifted from Cl to I (409, 414, and 432 nm for Cl, Br, and I, respectively), which was quite opposite to the trend predicted based on the spectrochemical series in crystal field theory, which was in good agreement with the previous results of the calculated 5d → 4f transition energies of the Eu2+ activator based on the crystal field theory. Through photoluminescence, UV-visible absorbance, and XPS, it was elucidated that the red emission due to Eu3+ was strongly masked by the intensified blue emission associated with the small amount of Eu2+ in the blue-emitting EuOX (X = Cl, Br, and I). These materials may provide a platform for modeling new phosphors for application in solid-state lighting.

Biomodification of compromised extraction sockets using hyaluronic acid and rhBMP-2: An experimental study in dogs.

BACKGROUND: This experimental study aims to evaluate the effect of hyaluronic acid on healing of infected extraction sockets compared with recombinant human bone morphogenetic protein-2 (rhBMP-2). METHODS: Both third and fourth mandibular premolars of six beagle dogs were hemisected, and the distal roots were extracted at baseline. Subsequently, combined endodontic-periodontic lesions were induced at the remaining mesial roots. After 4 months, the mesial roots on both sides of the mandible were removed. Four sockets per dog were randomly allocated to four groups: Group 1, Control; Group 2, only absorbable collagen sponge (ACS: carrier); Group 3, 1% hyaluronic acid (HA) gel + ACS; and Group 4, rhBMP-2 + ACS. After 3 months of healing, the dogs were euthanized for microcomputed tomography and histologic analysis. RESULTS: After the lesion induction period (4 months), communication between the periodontal lesion and endodontic periapical lesion was observed at all remaining mesial roots. Alveolar bone overgrowth was observed in groups 3 and 4, but bone volume density was not significantly different among all groups. At the crestal portion, mineralization, and osteocalcin expression were higher in groups 3 and 4 than in groups 1 and 2. CONCLUSION: Treatment with HA can promote bone formation and improve the wound healing rate comparable to rhBMP-2 in infected extraction sockets.