Earticle

Purpose: The present study aimed to assess the effect of palatal thickness and reinforcement insertion on the three-dimensional precision of the mucosal surface of maxillary denture bases after polymerization. Methods: Fifteen edentulous maxillary casts were fabricated and divided into three groups (n=5). The convention, complete denture, double-layer of base plate wax (CCD) group was fabricated with a double-layer baseplate wax without reinforcement. The reinforcement material, complete denture, double-layer of base plate wax (RCD) group used the same wax thickness with reinforcement insertion, whereas the reinforcement, complete denture, triple- layer of base plate wax (RCT) group was fabricated with triple-layer wax and reinforcement. After conventional heat polymerization, the mucosal surfaces were scanned, and the STL data were analyzed using best-fit superimposition. Precision was quantified by measuring the surface deviation values (μm), and the color difference maps were generated for visual analysis. Statistical analysis was performed using one-way ANOVA and Duncan’s post hoc test (α=0.05). Results: The CCD group showed the lowest mean surface deviation (46.69±10.65 μm), followed by the RCD group (63.10±16.70 μm), and the RCT group (82.76±20.94 μm). Significant differences were observed among all groups (p<0.001). The color difference maps revealed more uniform deviation patterns in the CCD group, whereas the RCT group presented with broader negative deviations in the central palatal region and mixed deviation patterns in the peripheral areas. Conclusion: Increased palatal thickness and reinforcement insertion significantly influenced the three-dimensional precision of the denture based-mucosal surface. Thus, structural optimization considering both reinforcement design and thickness control is required to maintain morphological stability.

Purpose: This study aimed to evaluate the impact of pressurization on the three-dimensional accuracy—trueness and precision—of full-arch type IV dental stone models used in prosthodontics. Methods: Dental stone models were categorized into three groups based on the applied pressurization levels during the setting process: 0 bars (0B group), 2 bars (2B group), and 4 bars (4B group). A dental pressurization system was employed to maintain pressure levels of 0, 2, and 4 bars, respectively. The models were analyzed using three-dimensional scanning and superimposition techniques, comparing them with a master model. A colordifference analysis was performed, with a 10-μm tolerance for green zones to standardize error evaluation. Results: The 2B group (2 bars) exhibited the highest accuracy, with minimal mean errors in trueness and precision relative to the 0B and 4B groups. The 0B group demonstrated significant deformation, attributed to microbubble formation and structural instability during the setting process. In contrast, the 4B group experienced increased internal stress and uneven curing, leading to slight distortions. Conclusion: Moderate pressurization at 2 bars significantly enhances the accuracy of type IV dental stone models by reducing deformations and minimizing trueness and precision errors. These findings suggest that controlled pressurization during the setting process improves the overall quality of dental prostheses.

Purpose: The purpose of this study was to assess the fitness of anterior and posterior interim crowns fabricated by three different additive manufacturing technologies. Methods: The working model was digitized, and single crowns (maxillary right central incisor and maxillary right first molar) were designed using computer-aided design software (DentalCad 2.2; exocad). On each abutment, interim crowns (n=60) were fabricated using three types of additive manufacturing technologies. Then, the abutment appearance and internal scan data of the interim crown was obtained using an intraoral scanner. The fitness of the interim crowns were evaluated by using the superimposition of the three-dimensional scan data (Geomagic Control X; 3D Systems). The one-way analysis of variance and Tukey posterior test were used to compare the results among groups (α=0.05). Results: A significant difference was found in the fitness of the interim crowns according to the type of additive manufacturing technology (p<0.05). The posterior interim crown showed smaller root mean square value than the anterior interim crown. Conclusion: Since the fitness of the posterior interim crown produced by three types of additive manufacturing technology were all within clinically acceptable range (<120 μm), it can be sufficiently used for the fabrication of interim crowns.

Purpose: This study aimed to evaluate the effect of post-curing method on the flexural strength of provisional restorative resins produced by a digital light processing printer. Methods: A total of 20 specimens were produced, with a length of 64 mm, width of 10 mm, and thickness of 3.3 mm using a digital light processing printer. Two types of provisional restorative resins made with different post-curing methods were investigated and divided into conventional and vacuum groups. For the flexural strength test, each group was prepared by each method according to ISO 10477, and the flexural strength was measured with a universal testing machine. For statistical analysis, data were analyzed by independent t-test and Mann–Whitney U test. Results: The flexural strengths of the conventional and vacuum groups were 151.89 MPa and 131.94 MPa, respectively, showing a statistically significant difference (p<0.05). Conclusion: Within the limitation of this study, provisional restorative resins produced with vacuum demonstrated lower flexural strength than those produced with conventional postcuring method.

Background : Many factors affect foot and ankle biomechanics during walking, including gait speed and anthropometric characteristics. This study examined the effect of walking speed on lower limb joint motion during the walking. Method : Thirty two normal healthy subjects (16 men, 16 women) were recruited. Maximal dorsiflexion and excursion were measured at the and lower limbs joints during walking phase at three different cadences (80, 100, and 120 step/min), using a three-dimensional motion analysis system (smart bs-500). Result : The results show that walking speed should be considered when comparing gait parameters. As the walking speed increases, the lower limb joint angle increases(p<0.05). Conclusion : The results also suggest that slow walking speeds may decrease forefoot peak plantar pressure in patients with restricted low extremity range of motion who have a high risk of skin breakdown under the forefoot.

The application of three-dimensional (3D) printing is growing explosively in the medical field, and is especially widespread in the clinical use of fabricating upper limb orthosis and prosthesis. Advantages of 3D-printed orthosis compared to conventional ones include its lower cost, easier modification, and faster fabrication. Hands are the most common body parts involved with burn victims and one of the main complications of hand burns are finger joint contractures. Applying orthotic devices such as finger splints are a well-established essential element of burn care. In spite of the rapid evolution of the clinical use of 3D printing, to our knowledge, its application to hand burn patients has not yet been reported. In this study, the authors present a series of patients with hand burn injuries whose orthotic needs were fulfilled with the application of 3D-printed finger splints.

Objective To improve lower extremity function and balance in elderly persons, we developed a novel, three-dimensional interactive augmented reality system (3D ARS). In this feasibility study, we assessed clinical and kinematic improvements, user participation, and the side effects of our system.Methods Eighteen participants (age, 56?76 years) capable of walking independently and standing on one leg were recruited. The participants received 3D ARS training during 10 sessions (30-minute duration each) for 4 weeks. Berg Balance Scale (BBS) and the Timed Up and Go (TUG) scores were obtained before and after the exercises. Outcome performance variables, including response time and success rate, and kinematic variables, such as hip and knee joint angle, were evaluated after each session. Results Participants exhibited significant clinical improvements in lower extremity balance and mobility following the intervention, as shown by improved BBS and TUG scores (p<0.001). Consistent kinematic improvements in the maximum joint angles of the hip and knee were observed across sessions. Outcome performance variables, such as success rate and response time, improved gradually across sessions, for each exercise. The level of participant interest also increased across sessions (p<0.001). All participants completed the program without experiencing any adverse effects.Conclusion Substantial clinical and kinematic improvements were observed after applying a novel 3D ARS training program, suggesting that this system can enhance lower extremity function and facilitate assessments of lower extremity kinematic capacity.

Objective To evaluate the relationship between femoral muscle volume (FMV) and physiological outcomes after trans-femoral amputations (TFAs) affecting overall locomotor function in patients.Methods Seven individuals who underwent TFA and had been using a prosthesis participated in this cross-sectional study. Gait and balance were assessed using clinical tests, such as 10-m walk test, 6-minute walk test, Berg Balance Scale, and automatic balance system. Respiratory gas analysis was performed to check oxygen consumption rate. Five participants were evaluated for bilateral FMV by MR imaging and FMV was reconstructed using three-dimentional remodeling.Results In five participants, significant differences were found between the non-involved and involved sides in femur length, total FMV, and functional muscle volume (all p<0.01) in all groups except for the hip adductor volume. The %mean difference between the non-involved and involved sides was 30% for femur length, 52.55% for hip flexor volume, 26.55% for hip adductor volume, 51.86% for hip extensor volume, and 60.21% for knee extensor volume. The hip flexor volume to hip extensor volume ratio in the involved limb and oxygen consumption rate during comfortable gait were negatively correlated (r=-0.96, p=0.04).Conclusion In individuals who underwent unilateral TFA, hip girdle muscle imbalance in the involved limbs may be associated with oxygen consumption rate while using a prosthesis.

Background Low back pain caused lumbopelvic instability and the passive and active stabilizing system and neural control subsystem control lumbopelvic stability. Purpose The aim of this study was to identify three-dimensional motions of pelvic and trunk during one leg standing applying the pelvic compression belt. Study design One group pre- and post-test design. Methods Twenty three healthy participants volunteered for this study. For the pre-test, their pelvic and trunk motions were measured during one leg standing in stance of the dominant side using equipment without application of pelvic compression belt. The participants wore pelvic compression belt for 20 minutes on a daily basis for a week in standing position to get used to application of pelvic compression belt. After one week training, the participants were measured during one leg standing in stance of the dominant side using equipment with application of pelvic compression belt for the post-test. The three-dimensional motion analysis system was used to measure the motion of anterior-posterior tilt, medial-lateral tilt, and rotation of the pelvis, as well as anterior-posterior flexion, lateral flexion, and rotation of the trunk during one leg standing. Results The motion of anterior-posterior tilt, medial-lateral tilt, and rotation of the pelvis were significantly decreased in the post-test than pre-test during one leg standing (p<0.05). Also the motion of anterior-posterior flexion, lateral flexion, and rotation of the trunk were significantly decreased in the post-test than pre-test during one leg standing (p<0.05). Effect sizes for pelvic anterior-posterior tilt, anterior-posterior flexion, lateral flexion, and rotation of the trunk were medium between pre-test and post-test during one leg standing (d=055?0.75). Conclusions This study found the motions of the pelvis and trunk were decreased by the passive support of the pelvic compression belt during one leg standing. This finding suggests that the pelvic compression belt will help to improve the stability of lumbopelvis in back pain patients with lumbopelvic instability.

Background Although many different types of foot-toe orthoses have known to correct hallux valgus deformity, most previous studies focused on the effects of a foot-toe orthosis as a clinical intervention for hallux valgus (HV) on simple gait function or alignment of the foot and ankle joints. Purpose To investigate effects of a hard and soft type foot orthoses on three-dimensional (3D) kinetic moments of ankle joints known to contribute to ankle arthrosis in individuals with HV using a force platform system based on motion analysis during gait. Study design This was a repeated-measures design. Methods Kinetic 3D moment data were obtained from 26 participants with HV. Two force platforms were used to collect kinetic data in three different foot-toe orthosis conditions during free walking. Repeated-measures analysis of variance was used to determine the effect of each foot-toe orthosis condition on ankle moment variables. Results There were significant differences in the maximal plantar flexion moment, second peak eversion moment, and maximal external rotation moment occurred at the terminal stance phase of the ankle joints between without foot orthosis and hard foot orthosis conditions (p<0.05). In addition, there were significant differences in maximal plantar flexion moment occurred at the late stance phase during gait between without foot orthosis and soft foot orthosis conditions (p< 0.05). Conclusions The results indicated the potential relationship between HV deformity and ankle osteoarthrosis through increasing ankle moments at the terminal stance under the without foot toe orthosis condition. Particularly, the application of a hard foot toe orthosis could contribute to treatment and prevention of ankle osteoarthrosis as well as HV correction.

Background Few studies have been performed to investigate the correction of leg length discrepancy (LLD) on the kinetic characteristics of the knee joint using a shoe insole during gait among those who must stand while working. Purpose To verify three-dimensional (3D) knee joint moments using a 3D motion capture system and force platforms with and without insoles during gait in standing workers with LLD. Study design This was a repeated-measures design. Methods Twenty-seven standing workers with LLD participated in this study. Kinetic data of the knee joint were collected using a motion analysis system and two force platforms. The participants were asked to walk freely along a 6-m walkway wearing a standard pair of shoes or standard shoes with an LLD-corrected insole. Repeated-measures analysis of variance (ANOVA) was used to compare the knee joint moments according to shoe conditions and limb sides. Results There were significant differences in most moment variables related to the knee joint in participants with LLD-corrected insoles worn on the short limb except for the knee moments of adduction, abduction, and internal rotation (p<0.05). Significant differences were shown in the maximal moment of knee adduction, abduction, internal rotation, and external rotation between the long and short legs when the participants wore standard shoes only during gait (p<0.05). Conclusions The results demonstrated a significant association between the imbalance of the knee moments and LLD among retail staff who must stand while working. Therefore, the results of this study will be useful in explaining the incidence and biomechanical characteristics of knee osteoarthritis in standing workers with LLD

Objective To assess the intra-rater and inter-rater reliability for measuring femoral anteversion angle (FAA) by a radiographic method using three-dimensional computed tomography reconstruction (3D-CT).Methods The study included 82 children who presented with intoeing gait. 3D-CT data taken between 2006 and 2014 were retrospectively reviewed. FAA was measured by 3D-CT. FAA is defined as the angle between the long axis of the femur neck and condylar axis of the distal femur. FAA measurement was performed twice at both lower extremities by each rater. The intra-rater and inter-rater reliability were calculated by intraclass correlation coefficient (ICC). Results One hundred and sixty-four lower limbs of 82 children (31 boys and 51 girls, 6.3±3.2 years old) were included. The ICCs of intra-rater measurement for the angle of femoral neck axis (NA) were 0.89 for rater A and 0.96 for rater B, and those of condylar axis (CA) were 0.99 for rater A and 0.99 for rater B, respectively. The ICC of inter-rater measurement for the angle of NA was 0.89 and that of CA was 0.92. By each rater, the ICCs of the intra-rater measurement for FAA were 0.97 for rater A and 0.95 for rater B, respectively and the ICC of the inter-rater measurement for FAA was 0.89. Conclusion The 3D-CT measures for FAA are reliable within individual raters and between different raters. The 3D-CT measures of FAA can be a useful method for accurate diagnosis and follow-up of femoral anteversion.

Cooperative beamforming (CB), where spatially distributed nodes synchronize their transmit phases to maximize the power of their combined signal at a desired receiver, can be used as an effective solution for hardware-limited nodes to achieve communication range extension. Thus, CB demonstrates effectiveness in providing higher reliability, lower latency, and extended transmission range for nodes in non-terrestrial networks (NTNs), which inherently face power and hardware limitations. In this paper, we consider the CB technique using UAVs in three-dimensional (3D) networks and analyze the average beampattern of the virtual antenna array constructed by the multiple UAVs. Further, because the mobile nature of the UAVs may cause carrier frequency offsets (CFOs), we analyze the impact of the CFO using the non-parametric kernel method. The simulation and analytical results show that the peak average beampattern degrades by about 3 dB with the CFO standard deviation of 1 kHz, which emphasizes the significance of frequency synchronization.

Objective: To investigate long-term changes in femoral anteversion angle (FAA) in children with intoeing gait and to identify factors that affect FAA changes.Methods: We retrospectively analyzed three-dimensional computed tomography data from 2006 to 2022 of children with intoeing gait with ≥3 years of follow-up without active treatment. The study examined the mean changes in FAA, the effects of sex, age, and initial FAA on FAA change, and mean FAAs by age. Changes in FAA severity up to eight years of age were also observed and analyzed by sex.Results: A total of 126 lower limbs of 63 children (30 males, 33 females) with intoeing gait were included, with a mean age of 5.11±1.05 years and a mean follow-up period of 43.59±7.74 months. The initial FAA was 41.42°±8.29° and the follow-up FAA was 33.25°±9.19°, indicating a significant decrease (p<0.001). Significant correlations were observed between age and changes in FAA, as well as between initial FAA and changes in FAA (r=0.248, p=0.005; r=-0.333, p<0.001). At age 8 years, only 22 limbs were classified as having mild FAA severity.Conclusion: During the follow-up period, children with intoeing gait had a significant decreased in FAA. No significant difference in FAA change was found between sex, but younger children and those with greater initial FAA were more likely to have decreased FAA. However, most children retained moderate to severe severity of increased FAA. Further studies are required to validate these findings.

Objective To evaluate femoral anteversion angle (FAA) change in children with intoeing gait depending on age, gender, and initial FAA using three-dimensional computed tomography (3D-CT). Methods The 3D-CT data acquired between 2006 and 2016 were retrospectively reviewed. Children 4 to 10 years of age with symptomatic intoeing gait with follow-up interval of at least 1 year without active treatment were enrolled. Subjects were divided into three groups based on age: group 1 (≥4 and <6 years), group 2 (≥6 and <8 years), and group 3 (≥8 and <10 years). Initial and follow-up FAAs were measured using 3D-CT. Mean changes in FAAs were calculated and compared. Results A total of 200 lower limbs of 100 children (48 males and 52 females, mean age of 6.1±1.6 years) were included. The mean follow-up period was 18.0±5.4 months. Average initial and follow-up FAA in children with intoeing gait was 31.1°±7.8° and 28.9°±8.2°, respectively. The initial FAA of group 1 was largest (33.5°±7.7°). Follow-up FAA of group 1 was significantly reduced to 28.7°±9.2° (p=0.000). FAA changes in groups 1, 2, and 3 were -6.5°±5.8°, -6.4°±5.1°, and -5.3°±4.0°, respectively. These changes of FAA were not significantly (p=0.355) different among the three age groups. However, FAA changes were higher (p=0.012) in females than those in males. In addition, FAA changes showed difference depending on initial FAA. When initial FAA was smaller than 30°, mean FAA change was -5.6°±4.9°. When initial FAA was more than 30°, mean FAA change was -6.8°±5.4° (p=0.019). Conclusion FAA initial in children with intoeing gait was the greatest in age group 1 (4?6 years). This group also showed significant FAA decrease at follow-up. FAA changes were greater when the child was a female, younger, and had greater initial FAA.

Objective To investigate the effects of adjuvant mental practice (MP) on affected upper limb function following a stroke using three-dimensional (3D) motion analysis.Methods In this AB/BA crossover study, we studied 10 hemiplegic patients who had a stroke within the past 6 months. The patients were randomly allocated to two groups: one group received MP combined with conventional rehabilitation therapy for the first 3 weeks followed by conventional rehabilitation therapy alone for the final 3 weeks; the other group received the same therapy but in reverse order. The MP tasks included drinking from a cup and opening a door. MP was individually administered for 20 minutes, 3 days a week for 3 weeks. To assess the tasks, we used 3D motion analysis and three additional tests: the Fugl-Meyer Assessment of the upper extremity (FMA-UE) and the motor activity logs for amount of use (MAL-AOU) and quality of movement (MAL-QOM). Assessments were performed immediately before treatment (T0), 3 weeks into treatment (T1), and 6 weeks into treatment (T2).Results Based on the results of the 3D motion analysis and the FMA-UE index (p=0.106), the MAL-AOU scale (p=0.092), and MAL-QOM scale (p=0.273), adjuvant MP did not result in significant improvements.Conclusion Adjuvant MP had no significant effect on upper limb function following a stroke, according to 3D motion analysis and three clinical assessment tools (the FMA-UE index and the two MAL scales). The importance of this study is its use of objective 3D motion analysis to evaluate the effects of MP. Further studies will be needed to validate these findings.

Purpose: This study aimed to compare the marginal and internal fits of metal three-unit fixed dental prosthesis (FDP) cast from wax and resin patterns produced using milling and three-dimensional (3D) printing technologies. Methods: To fabricate three-unit FDPs, the maxillary right first premolar and molar were prepared on an experimental model (AG-3 ZPVK, Frasaco GmbH), which was then duplicated in metal. The metal model was replicated, and working casts were fabricated using a type IV dental stone. These stone models were scanned using a desktop scanner to fabricate virtual models, allowing for the digital design of the three-unit FDPs. Overall, 30 patterns were fabricated using milling and 3D printing technologies (n=15). Subsequently, all patterns were cast into metal FDPs following conventional laboratory procedures. The marginal and internal fits of the fabricated metal FDPs were evaluated by scanning their inner and outer surfaces in situ on the metal model, followed by digital analysis. Differences in the fit between the two groups of FDPs were analyzed using an independent samples t-test (α=0.05). Results: A significant difference in marginal fit was observed between FDPs fabricated using milling and 3D printing technologies (p<0.001). The milling group exhibited superiority to the 3D printing group in terms of marginal fit (p<0.05). Conclusion: For the fabrication of wax patterns, the milling technology showed superiority to the 3D printing technology in terms of marginal fit for metal three-unit FDPs.

The follicle stimulating hormone receptor (FSHR) is a glycoprotein hormone, that belongs to the GPCR superfamily. FSHR plays a major role in reproduction. The aberrant activation of FHS receptor leads to infertility and several reproductive disorders. The recently recognized roles of the FSHR in diverse extragonadal tissues is also closely related to Alzheimer’s disease and cancers. Analysing the structural characteristics of the receptor is important in understanding the pathophysiology of diseases associated with the receptor. In this present study, homology modelling of FSHR-TM domain was developed using four different templates. Totally 20 models were developed using single template-based approach and selected three based on the validation of RC plot, RMSD, ProSA, QMEAN and ERRAT values. The developed models would be useful for further research on the structural characteristics and binding characteristics of the FSHR-TM domain.

본 삼차원 선택적 산화를 이용하여 20 nm 수준의 핀 폭과 점진적으로 증가된 소스/드레인 확장 영역을 갖는 핀 채널을 벌크 실리콘 기판에 제작하였다. 제안된 기법을 이용하여 삼차원 소자를 제작하기 위한 공정기법 및 단계를 상세히 설명하였다. 삼차원 소자 시뮬레이션을 통해, 제안된 소자의 주요 특징과 특성을 기존 FinFET 및 벌크 FinFET 소자와 비교하였다. 제안된 삼차원 선택적 산화 방식의 핀 채널 MOSFET는 기존의 소자들과 비교하여 더 큰 구동 전류, 더 높은 선형 트랜스컨덕턴스, 더 낮은 직렬 저항을 가지며, 거의 유사한 수준의 소형화 특성을 보이는 것을 확인하였다.

A fin channel with a fin width of 20 nm and a gradually increased source/drain extension regions are fabricated on a bulk silicon wafer by using a three-dimensional selective oxidation. The detailed process steps to fabricate the proposed fin channel are explained. We are demonstrating their preliminary characteristics and properties compared with those of the conventional fin field effect transistor device (FinFET) and the bulk FinFET device via three-dimensional device simulation. Compared to control devices, the three-dimensional selective oxidation fin channel MOSFET shows a higher linear transconductance, larger drive current, and lower series resistance with nearly the same scaling-down characteristics.

To extend the application of digital technology to the replication of artifacts, meticulous details of the process and the diversity of three-dimensional (3D) printing output materials need to be supplemented. Thus, in this study, a bronze mirror with Hwangbichangcheon inscription was digitalized by 3D scanning, converted into a voxel model, and virtual conservation treatment was performed using a haptic device. Furthermore, the digital mold of the bronze mirror completed by Boolean modeling was printed using a 3D sand-printer. Such contactless replication based on digital technology reflects the stability, precision, expressivity, collectivity, durability, and economic feasibility of artifacts. Its application can be further extended to cultural products as well as such areas as education, exhibition, and research. It is expected to be in high demand for metal artifacts that require casting. If empirical studies through experimental research on casting are supplemented in the future, it could extend the application of digital technology-based contactless replication methods.