Quantitative anatomical analysis of facial expression using a 3D motion capture system: Application to cosmetic surgery and facial recognition technology

The topography of the facial muscles differs between males and females and among individuals of the same gender. To explain the unique expressions that people can make, it is important to define the shapes of the muscle, their associations with the skin, and their relative functions. Three‐dimensional (3D) motion‐capture analysis, often used to study facial expression, was used in this study to identify characteristic skin movements in males and females when they made six representative basic expressions. The movements of 44 reflective markers (RMs) positioned on anatomical landmarks were measured. Their mean displacement was large in males [ranging from 14.31 mm (fear) to 41.15 mm (anger)], and 3.35–4.76 mm smaller in females [ranging from 9.55 mm (fear) to 37.80 mm (anger)]. The percentages of RMs involved in the ten highest mean maximum displacement values in making at least one expression were 47.6% in males and 61.9% in females. The movements of the RMs were larger in males than females but were more limited. Expanding our understanding of facial expression requires morphological studies of facial muscles and studies of related complex functionality. Conducting these together with quantitative analyses, as in the present study, will yield data valuable for medicine, dentistry, and engineering, for example, for surgical operations on facial regions, software for predicting changes in facial features and expressions after corrective surgery, and the development of face‐mimicking robots. Clin. Anat. 28:735–744, 2015. © 2015 Wiley Periodicals, Inc.     

The continuum of hip range of motion: From soft-tissue restriction to bony impingement

Traditional studies of hip kinematics have not identified which anatomic structures limit the range of motion (ROM) when the hip is placed in different maneuvers. In this study, we attempted to answer two questions: (a) During which maneuvers is the motion of the hip limited by bony impingement between the femur and pelvis? (b) When is hip ROM determined by the constraint of soft tissues and to what extent? ROM of eight cadaveric hips was measured in 17 maneuvers using a motion capture system. The maneuvers were recreated in silico using 3D CT models of each specimen to detect the occurrence of bony impingement. If bony impingement was not detected, the variable component of 3D hip motion was increased until a collision was detected. The difference between the virtual ROM at the point of bony impingement and the initial ROM measured experimentally was termed as the soft-tissue restriction. The results showed that bony impingement was present in normal hips during maneuvers consisting of high abduction with flexion, and high flexion combined with adduction and internal rotation. At impingement-free maneuvers, the degree of soft tissue restriction varies remarkably, ranging from 4.9° ± 3.8° (internal rotation) at 90° of flexion to 80.0° ± 12.5° (internal rotation) at maximum extension. The findings shed light on the relative contributions of osseous and soft tissues to the motion of the hip in different maneuvers and allow for a better understanding of physical exams of different purposes in diagnosing bone- or soft tissue-related diseases.     

颞下颌关节强直动物模型中最大张口度与强直严重程度关系研究

目的　研究主、被动最大张口度（AMMO、PMMO）与颞下颌关节强直严重程度的关系。方法　选取28只健康雄性绵羊随机分为实验组和对照组，每组各14只。实验组绵羊双侧颞下颌关节模拟髁突矢状骨折，其中左侧翼外肌被切断以阻断其功能；对照组绵羊未进行手术。于术前及术后12、24周对所有绵羊体重、AMMO、PMMO、颞下颌关节形态学特点进行测量评估。结果　实验组只有右侧保留翼外肌功能的颞下颌关节发生了骨强直。术后12、24周，实验组绵羊AMMO、PMMO、极限距离均显著低于对照组，差异均有统计学意义（均P < 0.05）。实验组绵羊AMMO和PMMO与骨融合区宽度、长度、面积及钙化程度均呈负相关（均P < 0.05），其中骨融合区面积为主要影响因素（术后12、24周相关系数r分别为-0.94、-0.95）。结论　颞下颌关节强直动物模型中阻断翼外肌功能可阻止骨强直的发生；对于早期髁突矢状骨折，可通过牙合垫或牙合板进行张口训练，进而阻断翼外肌功能。当颞下颌关节发生骨强直时，骨融合区面积越大，张口受限越明显。     

Rapid genome reshaping by multiple-gene loss after whole-genome duplication in teleost fish suggested by mathematical modeling

Whole-genome duplication (WGD) is believed to be a significant source of major evolutionary innovation. Redundant genes resulting from WGD are thought to be lost or acquire new functions. However, the rates of gene loss and thus temporal process of genome reshaping after WGD remain unclear. The WGD shared by all teleost fish, one-half of all jawed vertebrates, was more recent than the two ancient WGDs that occurred before the origin of jawed vertebrates, and thus lends itself to analysis of gene loss and genome reshaping. Using a newly developed orthology identification pipeline, we inferred the post–teleost-specific WGD evolutionary histories of 6,892 protein-coding genes from nine phylogenetically representative teleost genomes on a time-calibrated tree. We found that rapid gene loss did occur in the first 60 My, with a loss of more than 70–80% of duplicated genes, and produced similar genomic gene arrangements within teleosts in that relatively short time. Mathematical modeling suggests that rapid gene loss occurred mainly by events involving simultaneous loss of multiple genes. We found that the subsequent 250 My were characterized by slow and steady loss of individual genes. Our pipeline also identified about 1,100 shared single-copy genes that are inferred to have become singletons before the divergence of clupeocephalan teleosts. Therefore, our comparative genome analysis suggests that rapid gene loss just after the WGD reshaped teleost genomes before the major divergence, and provides a useful set of marker genes for future phylogenetic analysis.The recent rapid growth of genome data has made it possible to clarify major evolutionary events that have shaped eukaryote genomes, such as gene duplication, chromosomal rearrangement, and whole-genome duplication (WGD) (1). In particular, WGD events, known to have occurred in several major lineages of flowering plants (2), budding yeasts (3), and vertebrates (4) (Fig. 1A), are considered to have had a major impact on genomic architecture and consequently organismal features.Open in a separate windowFig. 1.Inferred spatiotemporal process of gene loss and persistence after TGD in teleost ancestors. (A) The estimated numbers of gene loss events in the teleost phylogeny, time-scaled tree of vertebrates (11, 41) with the timing of genome duplication events at the base of vertebrates (VGD1/2) and teleosts (TGD), and the number of extant species (26). Species used in this study are connected by solid branches. The numbers were parsimoniously inferred from the presence or absence of TGD-derived gene lineage pairs belonging to 6,892 orthogroups and mapped onto the time points of TGD (306 Mya), nodes a–g (a: 245 Mya; b: 158; c: 120; d: 105; e: 41; f: 164; g: 86) (11), and h (74 Mya) (28). On the left side of the tree, ortholog arrangements are compared between representatives (connected by bold branches in the tree) by CIRCOS (circos.ca) using orthology information for 5,655 orthogroups belonging to the 1to1 category (Fig. S2). (B) Definition of terms relating to WGD events. An orthogroup is a monophyletic group containing WGD-derived paralogs (gene lineages) of all focal species (Sp1) and orthologs of their sister species (Sp2), ignoring lineage-specific gene duplications (GeneA-1′ and -1″) or gene loss (GeneA-1″). (C) Approximation of the pattern of the number of gene loss and persistence events associated with TGD. The estimated number of retained paired gene lineages at nodes a to h and current teleosts (Ca, Ze, Co, Ti, Pl, Me, St, Te, and Fu) were used to compare the fit of the one-phase [αe^–2_μt (14)] and two-phase models. (D) Region of C detailing the recent pattern of gene loss. The solid and dashed curves have been corrected upward to remove the bias expected to result from parsimony analysis. These approximations are effectively insensitive to fluctuations in the estimated numbers of gene lineage pairs and times for the TGD event and ancestral nodes (a to h) (SI Text). The evolutionary scenario is essentially unchanged if the number of gene lineage pairs estimated without the BS 70% criterion or the divergence times estimated by nuclear gene (28)/mitochondrial genome (42) data were used. Note that the two-phase model can be roughly approximated by a double-exponential curve.Duplicate genes generated by WGD are typically assumed to be redundant and therefore subsequently lost in a stochastic manner. Comparative genome studies have suggested that 90% of duplicate genes were rapidly lost (5) by a neutral process (6) after WGD in budding yeast, but 20–30% of them were retained in human (7) even after several hundred million years. However, few genome-wide studies have addressed the temporal pattern of gene loss or persistence after WGD with reference to a reliable timescale (but see refs. 6 and 8). Such examination is indispensable for understanding when duplicate genes were lost and, consequently, genome structures were reshaped, during vertebrate diversification after the WGD (Fig. 1).To examine the detailed process of duplicate gene loss after WGD, one needs to estimate the number (proportion) of remaining duplicates in extant and ancestral species. For this purpose, both (i) reliably time-calibrated phylogenetic trees of species and (ii) well-annotated genomes are required. These two requirements have been met for several vertebrate lineages, including some teleost fishes. Given this, the next step should be to accurately estimate orthology and paralogy relationships of all of the genes that experienced WGD. For the analysis of gene orthology and paralogy, a homology search- or synteny-based approach has usually been used (9). In addition to the homology search-based approach (e.g., COGs and OrthoDB), a phylogenetic tree-based approach has also been introduced (e.g., Ensembl and PhylomeDB) (9). Recent developments of tree search algorithms and increased computing power allow a sophisticated tree-based approach, comparing each gene tree with the species tree. Such an approach is indispensable for the effective analysis of gene orthology and paralogy across many species, providing us with a powerful opportunity to investigate genome evolution after WGD.Here, we aim to investigate the gene loss/persistence pattern using genome-wide data, focusing on what is known as the teleost genome duplication (TGD). TGD is estimated to have occurred in an ancestor of teleosts (Fig. 1A) but after the divergence of tetrapods and teleosts (10). Thus, it is a relatively recent WGD shared by a large vertebrate group, i.e., the Teleostei. For teleosts, reliably time-calibrated phylogenies, including phylogenetic position and timing of the TGD event, are available (e.g., ref. 11). In addition, well-annotated whole-genome data from at least nine phylogenetically representative teleost species (cave fish, zebrafish, cod, tilapia, platyfish, medaka, stickleback, Tetraodon, and fugu) are now available from Ensembl (12). In the present study, we inferred the timing of rapid genome reshaping through gene loss after TGD by estimating the temporal and genomic positional (spatiotemporal) loss/persistence pattern of TGD-derived gene lineage pairs (Fig. 1B) over the past several hundred million years, using accurate tree-based orthology estimation (Fig. S1) and a reliable time-calibrated teleost tree. We investigated the mechanism of rapid gene loss after TGD by fitting a newly developed model for the observed temporal pattern of gene loss. This new model is necessary because standard models, based upon random and independent loss of duplicate genes, fail to fit our data. Our model analysis explicitly includes both the possibility of the loss of multiple genes in single events, and also the known phylogeny of the relevant species. The significance of the inclusion of events that result in the loss of multiple genes is that it reproduces the two phases of loss. The inclusion of known phylogeny allows us to correct for the bias associated with parsimony analysis.     

Anthropometric analysis of maxillary anterior buccal bone of Korean adults using cone-beam CT

PURPOSE

The aim of this study was to evaluate the thickness of buccal and palatal alveolar bone and buccal bony curvature below root apex in maxillary anterior teeth of Korean adults using Cone-beam CT images.

MATERIALS AND METHODS

The 3D image was reconstructed with dicom file obtained through CBCT from 20 - 39 year old Korean subjects (n = 20). The thickness of buccal and palatal plate, root diameter, the buccal bony curvature angle below root apex and the distance from root apex to the deepest point of buccal bony curvature were measured on maxillary anterior teeth area using OnDemand3D program.

RESULTS

Mean thickness of buccal plate 3 mm below CEJ was 0.68 ± 0.29 mm at central incisor, 0.76 ± 0.59 mm at lateral incisor, and 1.07 ± 0.80 mm at canine. Mean thickness of palatal plate 3 mm below CEJ was 1.53 ± 0.55 mm of central incisor, 1.18 ± 0.66 mm of lateral incisor, 1.42 ± 0.77 mm of canine. Bucco-lingual diameter 3 mm below CEJ was 5.13 ± 0.37 mm of central incisor, 4.58 ± 0.46 mm of lateral incisor, and 5.93 ± 0.47 mm of canine. Buccal bony curvature angle below root apex was 134.7 ± 17.5° at central incisor, 151.0 ± 13.9° at lateral incisor, 153.0 ± 9.5° at canine. Distance between root apex and the deepest point of buccal bony curvature of central incisor was 3.67 ± 1.28 mm at central incisor, 3.90 ± 1.51 mm at lateral incisor, and 5.13 ± 1.70 mm at canine.

CONCLUSION

Within the limitation of this study in Korean adults, the thickness of maxillary anterior buccal plate was very thin within 1mm and the thickness of palatal plate was thick, relatively. The buccal bony curvature below root apex of maxillary central incisor was higher than that of lateral incisor and canine and it seems that the buccal bony plate below root apex of central incisor is most curved.     

Sinus floor elevation via hydraulic detachment and elevation of the Schneiderian membrane

OBJECTIVES: Minor sinus floor elevation is a method with relatively high predictability but is technically demanding. Improvement of the technique and increase in the predictability are desirable. MATERIAL AND METHODS: A clinical protocol for minor sinus floor elevation with SLA-ITI (large grit acid-etched implants with diameter of 4.8 mm) is described. Using trephine instead of spiral burrs enables the harvesting of autogenous grafts from the implant socket and guarantees a perfect implant socket. The latter is necessary for optimal implant anchoring and for the hydraulic seal between socket and the osteotome. The whole allows a hydraulic detachment of the Schneiderian membrane, where the blood cushion gradually detaches and elevates the membrane, preventing its contact with the graft. RESULTS: Eight patients were successfully treated with the method described above. No membrane perforation occurred and an uneventful healing was observed in all patients. All implants were loaded prosthodontically 3 months after the implantation. CONCLUSIONS: The clinical protocol presented provides high predictability in clinical outcome, together with extremely low morbidity and shortened surgery.     

Effect of low intensity laser irradiation on surgically created bony defects in rats

Low intensity lasers have been used by clinicians to improve healing and reduce pain in humans. Lasing also results in new bone formation around hydroxyapatite implants and a significant increase in the total bone area. However, the exact mechanism of cell biostimulation by laser is still unclear. This study biochemically assessed the effects of low intensity laser (Gallium-Arsenide) using 4 and 22.4 mW cm(-2) power density on the bone healing process after surgically creating bony cavities in rat mandibles. Rats (n = 24) were divided into two groups each treated with specific energy, 4 or 22.4 mW cm(-2), for 3 min each day post-surgery. Surgical cavities were created on both sides of the mandible: the left served as an untreated control, the right was treated with laser. All rats were sacrificed after 1, 2 and 4 weeks of treatment. In the newly formed callus, accumulation of radiocalcium and alkaline phosphatase activity was measured to indicate osteogenic activity. One-way anova with repeated measures showed that the low intensity laser using 4 mW cm(-2) power density significantly increased radiocalcium accumulation from 2 weeks post-surgery, whereas 22.4 mW cm(-2) had no effect. No changes were noted in the activity of alkaline phosphatase with the laser treatment. These results suggest that laser therapy of low power density is effective on the bone healing process in artificially created osseous cavities by affecting calcium transport during new bone formation.     

探讨3D影像下顺行髓内钉理想置入点与正常成年人股骨大转子最高点的联系

目的:利用3D影像分析正常成年人股骨大转子最高点与髓腔中线的关系,为顺行髓内钉理想置入点的确定提供参考。方法:检索2016年1月至2017年1月行股骨全长CT检查的正常成年人107例,男64例,女43例;年龄(51.7±16.4)岁;左侧54例,右侧53例。利用Volume Viewer软件重建3D影像,根据股骨大转子形态分为前峰型(anterior apex,AA),后峰型(posterior apex,PA),中峰型(middle apex,MA),无峰型(none apex,NA)4组;冠状及矢状面上根据前倾角度分别调整股骨至标准颈干角位(apparent neck shaft angle,ANSA)及真颈干角位(true neck shaft angle,TNSA),分别记为C-ANSA,C-TNSA,S-ANSA,S-TNSA,测量各组在上述4个位置上股骨髓腔中线至股骨大转子最高点的垂直距离(vertical distance,VD),并对测得的VD值进行统计学分析;多元线性回归法分析临床资料与VD值的关系。结果:(1)4组4个位置对应VD值比较,AA组、MA组在S-ANSA上的VD值比较差异无统计学意义;AA、MA、NA组在C-ANSA和C-TNSA上的VD值比较差异无统计学意义。(2)矢状面2个位置VD值比较,AA、MA、NA组VD值比较差异有统计学意义;冠状面2个位置VD值比较,PA、 NA组比较差异有统计学意义。(3)经多元线性回归获得SANSA和S-TNSA位置上VD值的预测方程,S-ANSA上R=0.343,F=3.409,P=0.012;S-TNSA上R=0.317,F=2.846,P=0.028,其中颈干角和性别是矢状位上VD值的影响因素,而与冠状面上2个位置的VD值大小无明显差异。结论 :(1)以股骨大转子最高点为解剖标志确定正常成年人股骨髓内钉进针点,须辨别股骨大转子形态以及明确观测体位后再对矢状面上前后偏移及冠状面的横向偏移进行估计。(2)矢状面上的前后偏移随着颈干角的增大而有所增大,且女性前后偏移程度较男性小。