The article presents the results of the technical-economical study regarding the optimization of fused deposition modeling (FDM) parameters (the height of the layer deposited in one pass-Lh and the filling percentage-Id) for the manufacture of Polyethylene Terephthalate Glycol (PETG) and Acrylonitrile Styrene Acrylate (ASA) parts. To carry out this technical-economical study, was used the fundamental principle of value analysis, which consists of maximizing the ratio between Vi and Cp, where Vi represents the mechanical characteristic, and Cp represents the production cost. The results of the study show that for tensile specimens made of PETG, the parameter that significantly influences the results of the Vi/Cp ratios is the height of the layer deposited in one pass, (Lh), and in the case of the compression specimens made of PETG, the parameter that significantly influences the results of the Vi/Cp ratios is filling percentage (Id). In the case of specimens manufactured via FDM from ASA, the parameter that decisively influences the results of the Vi/Cp ratios of the tensile and compression specimens is the filling percentage (Id). By performing optimization of the process parameters with multiple responses, we identified the optimal parameters for FDM manufacturing of parts from PETG and ASA: the height of the layer deposited in one pass, Lh = 0.20 mm, and the filling percentage, Id = 100%.

Genioplasty is a widely used surgical approach to address chin deformities by performing an osteotomy on the inferior border of the mandible to allow for comprehensive repositioning of the chin. This study aimed to compare the accuracy of freehand chin repositioning with a guided technique that employed specialised surgical guides. For this retrospective study, data from 30 adult patients who underwent orthognathic surgery to correct dentofacial deformities were analysed. All patients underwent virtual planning before surgery, with half of them treated using freehand chin repositioning and the other half using the guided technique. The surgical outcomes were measured and compared with the virtual plan to assess the positional and rotational accuracy of the techniques. In terms of translational assessment, noteworthy values that exceeded clinically acceptable limits were observed only in sagittal movement in the freehand group (0.97 mm, interquartile range (IQR) 0.73-2.29 mm). Regarding rotational accuracy, both groups exhibited an IQR that surpassed acceptable limits for pitch (3.26°, IQR 2.06-5.20 for the guided group and 2.57°, IQR 1.63-4.24° for the freehand group). The Mann-Whitney test indicated no statistical differences between the groups in any translational or rotational assessment. In conclusion, although there was no statistical difference, the guided technique proved effective in achieving clinically acceptable accuracy in all positions and almost all rotations, displaying superior results in sagittal positioning compared with the freehand technique. To fully harness the advantages of guides and to guarantee accuracy in all rotations, we recommend further research involving guides made of more rigid materials, and customised implants.

German chamomile (Matricaria chamomilla L.) is an essential oil- containing medicinal plant used worldwide. The aim of this study was to gain knowledge of the phytochemical composition and the analgesic and soporific activity of Matricaria chamomilla L. (German chamomile) flower extract and its amino acid preparations, to predict the mechanisms of their effects by molecular docking and to develop aqueous printing gels and novel 3D-printed oral dosage forms for the flower extracts. In total, 22 polyphenolic compounds and 14 amino acids were identified and quantified in the M. chamomilla extracts. In vivo animal studies with rodents showed that the oral administration of such extracts revealed the potential for treating of sleep disorders and diseases accompanied by pain. Amino acids were found to potentiate these effects. Glycine enhanced the analgesic activity the most, while lysine and β-alanine improved the soporific activity. The molecular docking analysis revealed a high probability of γ-aminobutyric acid type A (GABAA) and N-methyl-D-aspartate (NMDA) receptor antagonism and 5-lipoxygenase (LOX-5) inhibition by the extracts. A polyethylene oxide (PEO)-based gel composition with the M. chamomilla extracts was proposed for preparing a novel 3D-printed dosage form for oral administration. These 3D-printed extract preparations can be used, for example, in dietary supplement applications.

UNASSIGNED: To explore the effect of NaOH on the surface morphology of three-dimensional (3D) printed poly- L-lactic acid (PLLA) mesh scaffolds.
UNASSIGNED: The 3D printed PLLA mesh scaffolds were prepared by fused deposition molding technology, then the scaffold surfaces were etched with the NaOH solution. The concentrations of NaOH solution were 0.01, 0.1, 0.5, 1.0, and 3.0 mol/L, and the treatment time was 1, 3, 6, 9, and 12 hours, respectively. There were a total of 25 concentration and time combinations. After treatment, the microstructure, energy spectrum, roughness, hydrophilicity, compressive strength, as well as cell adhesion and proliferation of the scaffolds were observed. The untreated scaffolds were used as a normal control.
UNASSIGNED: 3D printed PLLA mesh scaffolds were successfully prepared by using fused deposition molding technology. After NaOH etching treatment, a rough or micro porous structure was constructed on the surface of the scaffold, and with the increase of NaOH concentration and treatment time, the size and density of the pores increased. The characterization of the scaffolds by energy dispersive spectroscopy showed that the crystal contains two elements, Na and O. The surface roughness of NaOH treated scaffolds significantly increased ( P<0.05) and the contact angle significantly decreased ( P<0.05) compared to untreated scaffolds. There was no significant difference in compressive strength between the untreated scaffolds and treated scaffolds under conditions of 0.1 mol/L/12 h and 1.0 mol/L/3 h ( P>0.05), while the compression strength of the other treated scaffolds were significantly lower than that of the untreated scaffolds ( P<0.05). After co-culturing the cells with the scaffold, NaOH treatment resulted in an increase in the number of cells on the surface of the scaffold and the spreading area of individual cells, and more synapses extending from adherent cells.
UNASSIGNED: NaOH treatment is beneficial for increasing the surface hydrophilicity and cell adhesion of 3D printed PLLA mesh scaffolds.
UNASSIGNED: 探讨NaOH蚀刻对3D打印聚左旋乳酸（poly- L-lactic acid，PLLA）网状支架表面形貌的影响。.
UNASSIGNED: 采用熔融沉积成型技术制备3D打印PLLA网状支架，并采用NaOH溶液对支架表面进行蚀刻处理；NaOH溶液浓度分别为0.01、0.1、0.5、1.0、3.0 mol/L，处理时间分别为1、3、6、9、12 h，共25种浓度/时间组合。处理后对支架微观形貌、能谱元素、表面粗糙度、亲水性、压缩强度以及细胞黏附、增殖等方面进行观测。以未处理支架作为正常对照。.
UNASSIGNED: 通过熔融沉积成型技术成功制备3D打印PLLA网状支架。经NaOH蚀刻处理构建了粗糙或微观孔洞状结构支架表面，且随NaOH浓度及处理时间增加，孔径及孔密度随之增加。能量色散光谱对样品表征显示材料表面晶体含有Na、O两种元素。经NaOH处理支架表面粗糙度均较未处理支架增加（ P<0.05）、接触角减小（ P<0.05）；0.1 mol/L/12 h、1.0 mol/L/3 h处理支架压缩强度与未处理支架差异无统计学意义（ P>0.05）, 其余处理支架压缩强度均小于未处理支架（ P<0.05）。细胞与支架共培养后，NaOH处理支架表面细胞增多，单个细胞铺展面积增大，黏附细胞伸出突触更多。.
UNASSIGNED: NaOH处理3D打印PLLA网状支架有利于增加支架表面亲水性及细胞黏附。.

BACKGROUND: The preparation of the middle mesial (MM) canal of mandibular molars represents a challenge because it is often curved, narrow, and close to the root concave. The purpose of this study was to evaluate the ex vivo shaping ability of 3 nickel-titanium (NiTi) rotary systems in the MM canal using 3D printed resin tooth replicas.
METHODS: A permanent mandibular first molar with a MM canal was acquired from a pool of extracted teeth and reproduced by a 3D printer. The resin tooth replicas (n = 18) were equally assigned to 3 groups for the evaluation of the shaping abilities of 3 NiTi rotary systems (OneShape [OS], Twisted Files [TF], and ProTaper Gold [PTG]) according to the manufacturer\'s recommendations. The tooth replicas were scanned by micro-computed tomography (micro-CT) twice before and after instrumentation of the mesiobuccal (MB), mesiolingual (ML), and MM root canals. After 3D reconstruction, the canal straightening, change of root canal volume and surface area, the mesial and distal canal wall thickness and canal transportation at the levels of 1, 2, and 3 mm below furcation were assessed. One-way variance analysis and Turkey\'s post hoc test were used for comparisons of the means among different groups, and paired-t test was used to compare the mesial and distal sides of the mesial roots.
RESULTS: As compared with OS and TF, the use of PTG in preparation of MM canals resulted in significantly more straightening of canal curvature (p < 0.05), greater post-instrumentation canal volume and surface area, and thinner mesial and distal remaining canal wall thickness at 1, 2 and 3 mm below furcation (all p < 0.05). Regarding the root canal transportation in the mesiodistal direction, there was no significant difference among the 3 instruments (all p > 0.05) after the preparation of the MB and ML canals. However, in the MM canal, more pronounced transportation was detected in the PTG group at 2 mm below furcation, and in the TF group at 3 mm below furcation as compared with the other 2 systems (both p < 0.05).
CONCLUSIONS: 3D printed tooth replicas have the advantages of consistency and can be an ideal model to evaluate the shaping ability of different instruments in the MM canal. OS and TF files performed similarly and both are appropriate for shaping the MM canal, while PTG may cause excessive and uneven resin removal, especially near the furcation, and may lead to root fragility and procedural errors.

UNASSIGNED: The aim of this study was to compare the efficacy of pre-adjusted three-dimensional (3D) plating system employing 3D printing with conventional 3D plating in the management of mandibular fractures.
UNASSIGNED: A randomised, clinical trial was conducted where the study sample (n = 20) was divided into two groups. In Group 1, 3D plate and in Group 2, pre-bent 3D plate was fixed to the fracture site. The parameters assessed were number of bends required for adaptation, duration of fixation, pain, occlusal stability, reduction in lingual splaying and post-operative complications.
UNASSIGNED: Statistically significant difference was seen for the number of bends required (P = 0.000, P < 0.01) and duration of fracture fixation (P = 0.001, P < 0.01). There was statistically significant difference between the values of pain during the adaptation of 3D plate (P = 0.033, P < 0.05).
UNASSIGNED: The application of pre-adjusted 3D plate is superior to conventional 3D plating in terms of reducing number of bends, duration of fixation and pain during adaptation.

UNASSIGNED: Cutting nails is an essential activity of daily living. In this study, a foot-operated safety nail clipper for people with stroke hemiplegia was developed in four phases using three-dimensional (3D) printing technology.
UNASSIGNED: A user was identified to develop a foot-operated, safe nail clipper for people with stroke hemiplegia (Phase 1). A single user repeatedly used the technology to determine necessary improvements (Phase 2). Then, the usability was evaluated by four people with disabilities (Phase 3) before the clipper was manufactured at multiple institutions to determine its reproducibility (Phase 4).
UNASSIGNED: The foot-operated safe nail clipper was upgraded during each phase. The Version 2.0 comprises twenty 3D printing materials and five readily-available materials.
UNASSIGNED: A foot-operated safety nail clipper was developed for people with stroke hemiplegia. The number of parts increased as the device was upgraded via the use of 3D printing and available materials. Based on a small-scale usability test, the device was best suited for people with stroke hemiplegia. The assistive device was shared with the assistive technology open platform as an open source. The four-phased process can be used to develop appropriate assistive technology devices through the Makers Movement in the future.
People with stroke hemiplegia who have limited hand movement have difficulty cutting their nails independently.The foot-operated safety nail clipper for people with stroke hemiplegia was developed using the four phases methodology to help them cutting their nails: (1) Identifying the heavy user, (2) single scale, (3) small scale, and (4) multi-site reproducibility.We hope that the four-phased process of designing and developing appropriate assistive technology (AAT) devices presents insights that can be used to develop AAT devices through the Makers Movement in the future.AAT based on digital fabrication can be released to the public based on open source for people with disability in a low resourced environment, and the 3D modelling design can be easily modified according to individual needs.

BACKGROUND: Reports on hand dysfunction and rehabilitation in SSc are quite scarce in the literature and mainly focus on functional assessment tools, such as the Duruoz Hand Index and the HAMIS test for evaluating hand mobility by simulating specific grasps with nine different objects.
OBJECTIVE: This study aimed to provide an adequate assessment methodology for hand grasp dysfunctions in patients suffering from systemic sclerosis (SSc) through the 16-grasp test.
METHODS: Case-control study.
METHODS: Ninety-seven consecutive SSc patients were recruited at our Scleroderma Unit, where a 16-grasp test was performed by all patients and supervised by an experienced hand therapist. Sixteen different patterns of grasp have been divided into power grasps and precision pinch and two more modalities: static and dynamic prehension evaluation on scale from 0 to 4. We also compared previous evaluations on 19 of patients recruited.
RESULTS: The majority of SSc patients (84 females and 13 males; mean age 56.0±12.0 years; mean disease duration 8.0±6.0 years) displayed grasp dysfunctions; in particular 48% and 54% reported slight difficulty in the right and left grasps respectively, 6% medium difficulty in both hands, and only 3% and 1% experienced severe difficulty respectively, while 31.5% had no issues in either hand. Our results showed that the limited cutaneous subset (lcSSc) scored a lower deficit for either grasp compared to diffuse form (dcSSc). No statistically significant differences in total grasp deficit had been noticed when comparing patients having a disease duration < 5 years or longer. In the retrospective study on 19 of these patients, 8 out of 10 lcSSc patients showed no significant changes, while in 2 out of 10, slight improvements were observed in both hands. However, in the dcSSc group, 4 out of 9 worsened bilaterally while the grasp scores for 5 of them remained unchanged.
CONCLUSIONS: Our study reported hand involvement in both lcSSc and dcSSc forms, more significantly in dcSSc patients. This test is intended to be a more objective means of assessing grasp alterations linked to scleroderma hand deformities. Furthermore, thanks to its intuitiveness, the test may be useful for engineers designing personalized ergonomic assistive devices.

UNASSIGNED: The purpose of this study was to conduct a randomized controlled clinical trial to compare and evaluate the effect of provisional restorations fabricated by two techniques, namely, conventional and three-dimensional (3D) printing processes on the peri-implant hard and soft tissues over early nonfunctional loaded implants in the mandibular posterior region.
UNASSIGNED: A randomized controlled clinical trial was conducted across 24 subjects broadly divided into two groups with 12 dental implants each, i.e., GpIC with conventionally fabricated provisional restoration and GpIID with 3D printed fabricated provisional restoration. The prosthetic phase was carried out at 2 weeks, and subjects were evaluated at baseline (at the time of prosthesis placement), 2 months, and 4 months for peri-implant marginal bone level, mucosal suppuration, sulcular probing depth, and modified sulcular bleeding index. Patient satisfaction was assessed using 5-item questionnaires at 4 months. The intragroup comparison for all the data was done using Wilcoxon signed-rank test. The intergroup comparison for all the data was done using Mann-Whitney U-test. The comparison of frequency of responses between GpIC and GpIID was done using Chi-square test. P < 0.05 was considered to be statistically significant.
UNASSIGNED: Nonsignificant difference was observed in all the hard and soft tissue parameters between the groups at baseline, 2 months, and 4 months (P > 0.05). Improvement in bleeding on probing was found to be greater around dental implants restored with 3D printed provisional restoration than dental implants restored with conventionally fabricated provisional restoration from baseline to 4 months of follow-up, and the difference in finding was statistically significant (P < 0.05). There was a statistically nonsignificant difference seen for the frequencies between the groups (P > 0.05) for all questions related to patient satisfaction.
UNASSIGNED: The effect of conventionally fabricated and 3D printed provisional restorations on peri-implant hard and soft tissues was comparable to each other on an early nonfunctionally loaded implant in the mandibular posterior region.

The aim of this study was to evaluate the accuracy of models of partially edentulous arches obtained by three-dimensional (3D) printing.
This was an in vitro study.
Fifteen partially edentulous models were evaluated, using two methods of measuring dimensions: virtual, using the Standard Tessellation Language files of the models and software (control group), and physical, through printing the models and digital caliper (test group). For both methods, measurements were made regarding the dimensions of the teeth (width and length - buccal/lingual or palatal/occlusal) and distances between the teeth.
For the variable of linear measurements (width and length) and distances between teeth of the same hemiarch, the Wilcoxon test was used, while for the variable between opposite hemiarches, the paired t-test was used.
In the evaluation of the linear measurements, a significant difference was observed only when the width of the molar tooth was analyzed (P = 0.014). When the buccal length was measured, all teeth had linear measurements provided by the virtual method that was lower than the physical (P = 0.000), as well as the lingual/palatal length in incisors (P = 0.003) and molars (P = 0.009) and in total (P = 0.001). As for the analyses between teeth, no difference was identified between the measurements provided by the virtual method compared to the physical one.
The 3D printer used to print partially edentulous models provided linear distortions in the teeth but without changes in the distances between teeth of the same hemiarch and between teeth of opposite hemiarches.