Three-Dimensional Prediction of the Nose for Facial Approximation in a Thai Population.

Most of the previous studies about nose prediction were concentrated only some landmarks of the nose. This study aimed to generate prediction equations for ten landmarks of the nose in the midline and alar regions for forensic facial approximation. The six midline landmarks were the sellion, nasion-pronasale posterior, nasion-pronasale anterior, pronasale, nasal drop, and subnasale.

Preoperative planning of medial opening wedge high tibial osteotomy using 3D computer-aided design weight-bearing simulated guidance: Technique and preliminary result.

Background: High tibial osteotomy (HTO) is an established treatment for uni-compartmental osteoarthritis with varus deformity in relatively active young patients with good knee mobility. The most important factor for success and low complications of HTO is the precise correction of osteotomy. The objective of this study was to evaluate the accuracy of pre-operative planning of open-wedge HTO using t3D computer-aided design (CAD) weight-bearing simulated guidance technique for the succession of surgery.

PCL/PHBV blended three dimensional scaffolds fabricated by fused deposition modeling and responses of chondrocytes to the scaffolds.

In this study, poly(ε-caprolactone)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PCL/PHBV) blended porous scaffolds were fabricated by fused deposition modeling (FDM). PCL/PHBV filaments, initially prepared at different weight ratios, that is, 100/0, 75/25, 50/50, and 25/75, were fabricated by the lay-down pattern of 0/90/45/135° to obtain scaffolds with dimension of 6.0 × 6.

Porous 45S5 Bioglass®-based scaffolds using stereolithography: Effect of partial pre-sintering on structural and mechanical properties of scaffolds.

Scaffolds made from 45S5 Bioglass® ceramic (BG) show clinical potential in bone regeneration due to their excellent bioactivity and ability to bond to natural bone tissue. However, porous BG scaffolds are limited by their mechanical integrity and by the substantial volume contractions occurring upon sintering. This study examines stereolithographic (SLA) methods to fabricate mechanically robust and porous Bioglass®-based ceramic scaffolds, with regular and interconnected pore networks and using various computer-aided design architectures.

3D CAD/reverse engineering technique for assessment of Thai morphology: Proximal femur and acetabulum.

Purpose: To assess morphological parameters of proximal femur and acetabulum in Thai population with three-dimensional measurement technique, and to analysis of collateral side symmetric, gender difference, and correlation between morphometric parameters.

Methods: Investigation was performed in 240 femurs. All three-dimensional femur models were acquitted from 64-slice spiral CT scanner.

Stress relieving behaviour of flowable composite liners: A finite element analysis.

The purpose of this study was to investigate the consequences of using flowable composite as a liner beneath class I resin composite restorations on polymerization shrinkage stress and occlusal force. Models of class I resin composite restorations were generated. A control model received no flowable composite liner.

Biomechanical performance of retrograde nail for supracondylar fractures stabilization.

The study compared the biomechanical performance of retrograde nail used to stabilize supracondylar fracture (three different levels) by means of finite element analysis. Three different nail lengths (200, 260, and 300 mm) of stainless steel and titanium nails were under consideration. Intact femur model was reconstructed from Digital Imaging and Communications in Medicine images of Thai cadaveric femur scanned by computed tomography spiral scanner, whereas geometry of retrograde nail was reconstructed with the data obtained from three-dimensional laser scanner.

Biocompatibility of hydroxyapatite scaffolds processed by lithography-based additive manufacturing.

The fabrication of hydroxyapatite scaffolds for bone tissue engineering applications by using lithography-based additive manufacturing techniques has been introduced due to the abilities to control porous structures with suitable resolutions. In this research, the use of hydroxyapatite cellular structures, which are processed by lithography-based additive manufacturing machine, as a bone tissue engineering scaffold was investigated. The utilization of digital light processing system for additive manufacturing machine in laboratory scale was performed in order to fabricate the hydroxyapatite scaffold, of which biocompatibilities were eventually evaluated by direct contact and cell-culturing tests.

Prevention of excessive medialisation of trochanteric fracture by a buttress screw: a novel method and finite element analysis.

This paper proposes a novel method of using an antero-posterior buttress screw at the distal fragment just below the fracture site in conjunction with the sliding hip screw (SHS) to resist excessive femoral medialisation. A virtual assessment of the effectiveness of this new method was performed using the finite element analysis. The results indicate that the use ofa sliding hip screw (SHS) combined with a buttress screw can help resistfemoral medialisation better than using an SHS with no buttress screw.

Optional entry point for retrograde femoral nailing: an anatomical study using the reverse engineering method.

Objective: To investigate the optimal entry point for retrograde femoral nailing using medical imaging and reverse engineering technologies.

Material And Method: One hundred and eight adult cadaveric femurs were scanned using a computed tomography (CT) scanner. To obtain three-dimensional models, medical imaging and reverse engineering technologies were used.

Rapid-prototype endoprosthesis for palliative reconstruction of an upper extremity after resection of bone metastasis.

Purpose: To present a rapid-prototype (RP) endoprosthesis replacement after tumor resection in patients with bone metastasis of the upper extremity. The short-term complications and functional outcomes were evaluated as well as the survival of patients and endoprosthesis.

Methods: Bone metastasis patients who required bone resection and endoprosthesis replacement were enrolled and consented before operation.

Bone tissue engineering scaffolding: computer-aided scaffolding techniques.

Tissue engineering is essentially a technique for imitating nature. Natural tissues consist of three components: cells, signalling systems (e.g.

Biomechanical evaluation of a novel porous-structure implant: finite element study.

Purpose: The biomechanical performance of a novel engineered porous-structure implant (EPSI) with various porosities and a conventional solid-structure implant (CSSI) was investigated and compared.

Materials And Methods: The three-dimensional finite element method was applied to titanium dental implant models placed in a block of bone that included both cortical and medullary bone. Five different pore sizes and porosities of the EPSI (58% porosity [PSI-58], 62% porosity [PSI-62], 71% porosity [PSI-71], 75% porosity [PSI-75], and 79% porosity [PSI-79]), were compared with the CSSI.

Scaffold library for tissue engineering: a geometric evaluation.

Tissue engineering scaffold is a biological substitute that aims to restore, to maintain, or to improve tissue functions. Currently available manufacturing technology, that is, additive manufacturing is essentially applied to fabricate the scaffold according to the predefined computer aided design (CAD) model. To develop scaffold CAD libraries, the polyhedrons could be used in the scaffold libraries development.

Mismatch analysis of humeral nailing: antegrade versus retrograde insertion.

Background: Closed humeral nailing is now considered an alternative treatment for humeral-shaft fracture. The nail can be inserted with either the antegrade or retrograde method. We investigated and compared the problem of geometric mismatch of the humeral nail to the humerus between the two methods of insertion.

Geometric mismatch analysis of retrograde nail in the Asian femur.

The geometric mismatch analysis of the retrograde nail was performed in 108 Asian cadaveric adult femora. The insertion was done virtually based on a three-dimensional geometric model derived from computed tomographic images. The investigation was performed at eight levels located at 120, 140, 160, 180, 200, 220 and 240 mm above the condylar surface.

Influence of graft quality and marginal bone loss on implants placed in maxillary grafted sinus: a finite element study.

The purpose of this study was to investigate the biomechanical effects of graft stiffness and progression of marginal bone loss (MBL) in the bone surrounding an implant placed in a maxillary grafted sinus based on the finite element method. The simulating model of graft stiffness as well as depth of MBL was varied to simulate nine different clinical scenarios. The results showed that the high-level strain distributions in peri-implant tissue increased with the increase in MBL depth when the stiffness of the graft was less than that of the cancellous bone (less stiffness graft models).

Craniometric study of Thai skull based on three-dimensional computed tomography (CT) data.

The present study revealed an advanced method using data obtained from three-dimensional computed tomography (3D CT) to evaluate the craniometric data of the Thai population. Ninty-one Thai cadaveric dry skulls from the Faculty of Medicine, Khon Kaen University were investigated in the present study. It enabled the authors to assess the three-dimensional anatomical landmarks in digital format without physical measurements.

A finite element study of stress distributions in normal and osteoarthritic knee joints.

Objective: To study the stress distributions in normal and osteoarthritic knee joints using the finite element method (FEM).

Material And Method: Three normal and three varus knee joints are included in the study. Computed tomography (CT) images of the lower extremities are used to create 3D geometric models consisting of bones, articular cartilages, menisci, and knee ligaments.

Three-dimensional morphometric study of the Thai proximal humerus: cadaveric study.

Seventy-six cadaveric humeri were investigated to study the three-dimensional morphometric data based on CT data. The present study was an advanced method to determine the 3D proximal humeral parameters for both intra and extra geometries through the utilization of medical imaging and reverse engineering techniques. The following parameters were calculated for each humerus and then compared with the 3D Caucasian data such as diameter of humeral head, articular surface thickness, inclination angle, retroversion angle, medial offset, posterior offset, curve length, radius of curvature, and mediolateral angle.

3D geometrical assessment of femoral curvature: a reverse engineering technique.

Objective: Investigate the 2D/3D geometry of femoral curvature and femoral length using the advanced technique of computerized tomography combined with reverse engineering techniques.

Material And Method: The present study was performed using reverse engineering technique based on CT data of 99 cadaveric femora. The femur was divided into three segments, proximal, mid-shaft, and distal regions by defining 35% and 65% of the femoral total length as a boundary of each region.

Fit-and-fill analysis of trochanteric gamma nail for the Thai proximal femur: a virtual simulation study.

The present study present a three-dimensional virtual simulation method to evaluate the fit-and-fill effect of the insertion of a trochanteric gamma nail (TGN) in 98 Thai dadaveric proximal femora. The circular best fit of the 2-dimensional cross-section of the femoral canal and the nail at 4 levels [d100, d120, d140 and d160] which were located at 100, 120, 140 and 160 mm distal to the tip of the greater trochanter were calculated. The evaluation of each level included, 1) the diameters of the medullary canal, 2) the percentage of area filled by the nail in the unreamed medullary canal, 3) the minimal reamer diameter that required enlargement of the canal to accommodate TGN insertion, 4) the minimal inner cortical reaming thickness that needed to be removed, 5) the percentage of cortical bone area that needed to be removed prior to nail insertion and 6) the deviation of the nail center from the center of the medullary canal.

Morphological study of the proximal femur: a new method of geometrical assessment using 3-dimensional reverse engineering.

This study presents a new method of using computerized tomography images combined with the reverse engineering technique to obtain and analyse the three-dimensional inner and outer geometry of the proximal cadaveric femur. Three-dimensional models were reconstructed from the computerized tomography images and approximated with 2D and 3D fitting algorithms based on reverse engineering methods. The following parameters were calculated for each femur: femoral head diameter, femoral neck axis, femoral shaft axis, anteversion angle and neck-shaft angle.