Sagittal Direction Research Articles

Walking–sliding experimental analysis of frictional characteristics socked feet

Simulation experiments and in-vivo experiments were widely employed for investigating sock-skin frictional characteristics. The simulation experiments usually was a type of sliding experiment which described the relative slip between fabric and artificial skin. The in-vivo approaches typically involved subjects adopting a variety of postures and friction between their clothing and the skin was estimated. However, simulation and in-vivo experiments were reported only separately. The connection between the two types of experiments was scarcely reported. To reveal the connection, we synchronously carried out two interrelated experiments, a natural walking experiment and sliding experiment, using the same sock fabric. In the natural walking experiment, the subject wearing socks walked on the force platform. Then the soles of these socks were cut out and were used in the soles-artificial skin sliding experiment. The coefficients of friction in the two types of experiments reflected some correlative frictional characteristics. We found the effect of the walking speed or sliding speed on the friction coefficient was not significant. While, water content increased the friction coefficient in the two experiment. Additionally, the friction in the coronal direction was smaller than that in the sagittal direction during walking. Through our efforts, we hope to bridge the simulation and in-vivo experiments and elucidate the frictional characteristics between the sock and insole.

Fibroglandular tissue distribution in the breast during mammography and tomosynthesis based on breast CT data: A patient-based characterization of the breast parenchyma.

PurposeTo develop a patient‐based breast density model by characterizing the fibroglandular tissue distribution in patient breasts during compression for mammography and digital breast tomosynthesis (DBT) imaging.MethodsIn this prospective study, 88 breast images were acquired using a dedicated breast computed tomography (CT) system. The breasts in the images were classified into their three main tissue components and mechanically compressed to mimic the positioning for mammographic acquisition of the craniocaudal (CC) and mediolateral oblique (MLO) views. The resulting fibroglandular tissue distribution during these compressions was characterized by dividing the compressed breast volume into small regions, for which the median and the 25th and 75th percentile values of local fibroglandular density were obtained in the axial, coronal, and sagittal directions. The best fitting function, based on the likelihood method, for the median distribution was obtained in each direction.ResultsThe fibroglandular tissue tends to concentrate toward the caudal (about 15% below the midline of the breast) and anterior regions of the breast, in both the CC‐ and MLO‐view compressions. A symmetrical distribution was found in the MLO direction in the case of the CC‐view compression, while a shift of about 12% toward the lateral direction was found in the MLO‐view case.ConclusionsThe location of the fibroglandular tissue in the breast under compression during mammography and DBT image acquisition is a major factor for determining the actual glandular dose imparted during these examinations. A more realistic model of the parenchyma in the compressed breast, based on patient image data, was developed. This improved model more accurately reflects the fibroglandular tissue spatial distribution that can be found in patient breasts, and therefore might aid in future studies involving radiation dose and/or cancer development risk estimation.

A new method for individual condylar osteotomy and repositioning guides used in patients with severe deformity secondary to condylar osteochondroma

BackgroundMandibular condylar osteochondroma (OC) could lead to facial morphologic and functional disturbances, such as facial asymmetry, malocclusion, and temporomandibular joint dysfunction. However, after condylar OC resection, the inaccurate reposition of the neocondyle still needs to be solved. The purpose of this study was to explore the feasibility of the condylar osteotomy and repositioning guide to reposition the neocondyle in the treatment of patients with severe deformity secondary to condylar OC.ResultsThree patients with severe deformity secondary to OC of the mandibular condyle were enrolled in this study. With the aid of condylar osteotomy and repositioning guide, condylar OC resection and repositioning were carried out, and the accuracy and stability of these guides were evaluated. All patients healed uneventfully, and no facial nerve injury and condylar ankylosis occurred. Compared with the computerized tomography scans in centric relation before surgery and 3 days after surgery, the results showed that the facial symmetry was greatly improved in all the patients. Also, after the superimposition of the condylar segments before surgery and 3 days after surgery, the postoperative reconstructed condyles had a high degree of similarity to the reconstruction of the virtual surgical planning. Observed from the sagittal and coronal directions, the measurements of condylar positions were very close to those of virtual surgical planning. Moreover, it also showed stable results after a 1-year follow-up.ConclusionsFor patients with severe deformity secondary to condylar OC, condylar osteotomy, and repositioning guide was expected to provide a new option for the improvement of facial symmetry and occlusal relationship.

Esthetic evaluation of profile photographs showing various sagittal and vertical patterns

The purpose of this study was to determine the esthetic preferences of people at different levels of society and also to determine whether this preference is affected by sex, age, education level, social status, geographic region, and individual profile factors. Facial profile photographs of 1 man and 1 woman, each having a profile designated as ideal (the ideal profile), were digitized. The sagittal and vertical dimensions of these photographs were modified, and 9 variations of each profile picture were obtained using different combinations of alterations. The photographs were scored by 373 participants. For the analysis, Mann-Whitney U and Kruskal Wallis-H tests were used in the comparison of the scores. The ideal profile was the most preferred in both sexes, whereas the least preferred was a severe Class III malocclusion with a reduced vertical dimension of 8mm. In general, esthetics decreased as it moved away from the ideal profile in a sagittal or vertical direction. Some factors from among those sampled (sex, age, education, social status, geographic region, and personal profile) affected esthetic preference, whereas others did not.

Corrección de mordida cruzada anterior de origen dental y recesión gingival en dentición mixta temprana. Reporte de caso

Introducción: La mordida cruzada anterior ocurre cuando los incisivos superiores ocluyen lingualmente a los inferiores, pudiendo ser de origen dental o esquelético. La corrección temprana de esta maloclusión favorece una correcta relación interincisiva, permitiendo el adecuado crecimiento y desarrollo en sentido sagital del complejo máxilo facial. Reporte del caso: Paciente masculino de 8 años de edad. Se realizó estudio ortodóncico completo siendo el diagnóstico cefalométrico Clase I y dentario de Clase I tipo 3 con retroinclinación de incisivos superiores, casoy mordida cruzada de origen dental. Presentó recesión gingival en encía vestibular de 41 y 31. El tratamiento realizado incluyó aparato removible con placa de levantamiento posterior, tornillo expansor anterior y arco de Eschler. Se realizó seguimiento por 16 meses, obteniendo el descruzamiento de la mordida anterior, conformación de arco e inclinación apropiada del incisivo superior. Conclusiones: El tratamiento de la mordida cruzada anterior de origen dentario puede ser logrado en dentición mixta utilizando mecánicas sencillas.

Three-dimensional periorbital asymmetry assessment of congenital microphthalmia children with a structured light 3D scanning system

Congenital microphthalmia is a rare phenotype characterized by eye growth retardation. Due to the lack of eyeball stimulation, children suffering from congenital microphthalmia always have bony orbital maldevelopment, which leads to facial asymmetry. In the present study, a structured light 3D scanning system was used as a novel method to measure the three-dimensional periorbital asymmetry in children with congenital microphthalmia.Children with unilateral congenital microphthalmia of 0–6 years old were enrolled in the present study. All participants underwent an ultrasound scan to measure the axial length, and accepted the structured light 3D scanning system for their periorbital appearance. The degree of periorbital asymmetry was evaluated using 17 facial landmarks within a three-dimensional cartesian coordinate system (the X-axis represented the horizontal direction, the Y-axis represented the vertical direction, and the Z-axis represented the sagittal direction). Paired student t-test and ANOVA were used in the present study. A three-dimensional periorbital topography was also established to further illustrate the periorbital asymmetry.A total of 67 children were recruited, which included 31 boys and 34 girls. The axial length on the affected side (12.28 ± 3.35 mm) was generally smaller than that on the unaffected side (20.54 ± 1.65 mm, P < 0.001). When grouped by age, the periorbital asymmetry mainly manifested in the Y-axis and Z-axis directions. The unaffected side had a higher orbitale superior (5.09 ± 0.35 vs. 3.02 ± 0.30, P < 0.001) and a lower orbitale inferior (−19.52 ± 0.51 vs. −16.90 ± 0.53, P < 0.001) in 0–1 year old group. Same performances were also found in the 1–3 and 3–6 age groups. When grouped according to the proportion of axial length on the bilateral sides, seven of the 12 Y-values and all 12 Z-values had statistical differences.The structured Light 3D scanning system may serve as a beneficial complementary tool for computed tomography, in order to better understand the periorbital deformities caused by congenital microphthalmia.

The comparison of maxillary and mandibular dental arch size in male and female Papuan in Surabaya: A cross-sectional study

Aim: The aim of this study was to analyze the differences in the size of maxillary and mandibular dental arch between Papuan males and females. Materials and Methods: An analytical cross-sectional study design was carried out in 12 Papuan males and 12 Papuan females aged above 18–25 years in the Surabaya. Raberin method was used to measure the maxillary and mandibular dental arches width in the dental cast in transversal (L33, L66, L77) and sagittal direction (L31, L61, L71). The statistical analysis was used to analyze the data normality by Kolmogorov–Smirnov test (P > 0.05). In addition, the independent t test was done to determine the differences between groups (P < 0.01). Results: The average sizes of the maxillary dental arch width in the transversal direction in Papuan males, respectively, L33, L66, and L77 were 35.86, 56.58, and 65.61 mm. The average sizes of the maxillary dental arch in the sagittal direction in men L31, L61, and L71 were 4.04, 35.60, and 46.41 mm. The average widths of the maxillary dental arch in a transversal direction in Papuan female L33, L66, and L77 were 32.45, 53.54, and 63 mm. The average sizes of the maxillary dental arch in the sagittal direction in female L31, L61, and L71 were 3.55, 31.94, and 42.42 mm. There was a significant difference between men and female maxillary dental arch in sagittal and transversal measurement (P < 0.01). Conclusion: Male Papuan has a bigger maxillary and mandibular dental arch width as compared to female Papuan. Evaluation of Papuan dental arches may help the orthodontist to determine the diagnosis and treatment plan in this population.

Analysis of the quality of orthodontic care for children with partial defects of dentition in the dental organizations of various forms of ownership

To conduct a comparative analysis of the quality of medical care for children and adolescents with dentoalveolar anomalies in dental medical organizations of different organizational and legal basis and forms of ownership. The analysis of orthodontic records of children and adolescents with dentoalveolar anomalies and factors predisposing to their development in 1032 patients aged from 6 months to 18 years was carried out with the use of orthodontic patient records classification of L.S. Persin (2020). The effectiveness of orthodontic care for children and adolescents with various forms of anomalies of the dentition was analyzed. The draft clinical guidelines have been developed depending on the patient model. As shown by the data of orthodontic records of patients, 12% of patients applied during the formation of occlusion of deciduous teeth, 9.2% of children in the early mixed dentition phase, 66.5% of patients in the late mixed dentition phase, and 12.2% of patients first admitted in the permanent dentition phase. As for the analysis of the quality of orthodontic care for children and adolescents with dentoalveolar anomalies in dental organizations of various forms of ownership, the results are controversial. Most often in the orthodontic charts data on dentition anomalies were filled, followed by the anomalies of the teeth, anomalies of occlusion in the sagittal direction, anomalies of occlusion in the vertical direction and partial defects of the dentition. Anomalies of soft tissue attachment, anomalies of occlusion of molars on the right and left with palatoocclusion, and anomalies of occlusion of molars on the right and left with linguo-occlusion were less common in orthodontic charts.

Method of microscopic imaging quality evaluation for board lens based on image parameter extraction of pinhole imaging

The modulation transfer function area (MTFA) of pinhole imaging and the MTFA relative variation ratio were used as the image surface parameters to quantitatively evaluate the microscopic imaging quality of the board lens. The light spot images located in different fields of view positions were obtained by using the pinhole imaging method to extract the modulation transfer function (MTF) of microscopic imaging system for board lens. The MTF mathematical model of lens system for board lens was established, and the MTFA in sagittal direction and meridian direction of edge field of view as well as the MTFA relative variation ratio were extracted to measure the microscopic imaging definition and image surface flatness of the measured lens. An experiment which was for measuring the board lens was carried out, and the microscopic imaging performance of the measured lens was quantitatively evaluated by using the proposed model and method. The results show that the Lens 2 can obtain the optimal microscopic imaging quality. The definition value of average power spectrum value (APSV), the gray mean gradient (GMG) and the laplacian summation (LS) were calculated respectively from the RGB bitmap images captured by these measured lens. The results show that the maximum parameter value of the APSV, GMG and LS of Lens 2 bitmap images is equal to 2.720 2, 17.024 4 and 94.921 2, respectively. At the same time, the bitmap images have the highest definition, which is consistent with the image surface parameter evaluation results, indicating that the proposed method used in the quantitative evaluation of microscopic imaging performance of board lens is accurate and effective, which is of great significance and engineering value to improve the online image probe design of the on-line visual ferrograph (OLVF).

Morphometric measurements of safety zones and orientation angles for freehand placement of revision screws in atlas lateral mass.

To demonstrate the possibility of revision screw placement to the atlas, as well as define the safety zones and orientation angles. This retrospective study analysed the records of four patients who were operated for AAI earlier. Because they needed revision of Atlas screws, they were re-operated after obtaining the measurements mentioned in this study. In addition, measurements of 50 healthy subjects were included in the study as the control group. Maximum screw lengths were also measured. Safe zone in the ideal sagittal direction were wider. As the screw projection becomes more cephalic direction in the sagittal plane, the safe zone for the screw becomes narrower. With the sagittal angle moving forwards cranially, the screw length becomes longer. Atlas lateral mass screws could be safely revised whenever needed. The fact that needs to be considered is that the angular range becomes narrower, and the screw length becomes longer when the screw is directed more cranially.

Comparison of neck extensor muscle endurance and cervical proprioception between asymptomatic individuals and patients with chronic neck pain

IntroductionNeck extensor endurance (NEE) and cervical proprioception are vital for maintaining cervical spine function and defects in these processes have been associated with chronic neck pain (CNP). The objectives of the study are 1) To investigate the association between NEE and cervical joint position error (JPE) in subjects with CNP; 2) to compare the cervical extensor endurance and cervical JPE of CNP subjects with those of asymptomatic controls; and 3) to determine the relationship between Pain Catastrophizing Scale (PCS) scores, NEE, and cervical JPE in subjects with CNP. MethodSixty-four participants (32 asymptomatic, 32 with CNP) participated in this comparative cross-sectional study. Cervical proprioception was assessed by measuring the absolute JPE in the sagittal and transverse directions. NEE was assessed using a clinical extensor endurance test. NEE capacity and JPE were compared and correlated between asymptomatic and CNP subjects. Pain catastrophic behavior was assessed using the Pain Catastrophizing Scale (PCS) in CNP subjects. ResultsCNP subjects showed lower NEE capacity (p < 0.001) and significantly larger JPEs (p < 0.001) than asymptomatic participants. NEE negatively correlated with JPEs in all directions (p < 0.001) in asymptomatic subjects and only neck extension errors showed a correlation in CNP subjects (r = −0.45, p = 0.009). PCS scores were negatively correlated with endurance capacity (r = −0.42, p = 0.017) and positively correlated with JPE (flexion: r = 0.57, p = 0.001). ConclusionCNP subjects showed impaired proprioception and lower endurance capacity compared to asymptomatic participants. Neck extension errors alone correlated with JPE in CNP subjects. PCS scores negatively correlated with NEE in subjects with CNP.

Comparison of 3-dimensional postoperative dental movement in Class III surgical correction with and without presurgical orthodontic treatment

BackgroundSurgery-first approach (SFA) is an emerging concept that surgically reposition the jaw bones without presurgical orthodontic treatment phase. The study investigated 3D dental movement in the postoperative orthodontic phase with orthodontic-first (OF) and SFA in orthognathic surgery (OGS). MethodsThis study included consecutive 40 patients (20, SF group; 20, OF group) skeletal Class III who underwent 2-jaw OGS correction. The data of cone-beam computed tomography were acquired at 3 stages with the scan of dental models to replace the dentition of the craniofacial images; at before OGS (T0), 1 week after OGS (T1) and at the completion of treatment (T2). The skeletal changes were obtained by overall superimposition. The post-operative dental movement was measured by 3D regional superimposition between T1 and T2. ResultsThere were no significant difference in the postsurgical orthodontic movement in both groups except significant upper and lower molars extrusion by 2 mm in the SF group. Both groups exhibited no significant difference in mandibular stability in sagittal and vertical directions. The amount of extrusion in the molars was correlated with a postoperative sagittal mandibular forward movement. The total treatment duration was significantly shorter 230 days in the SF group. ConclusionThe completion of the orthodontic treatment after OGS in the SFA was mainly accomplished through molar extrusive movement in both arches. The surgical setup of dental occlusion with 4 mm posterior open bite could be corrected during the postsurgical orthodontics in SFA through molar extrusion. The dental occlusion outcome was no different between OF and SFA.

A retrospective study of tailored surgery based on the mechanical balance principle for involutional entropion in the lower eyelid.

Involutional entropion in the lower eyelid is one of the most common eyelid disorders of the elderly. Despite the effectiveness of the widely used surgical procedures, recurrence rates have failed to improve. In this retrospective study, we aimed to assess surgical plans, effectiveness and safety of tailored surgery based on the mechanical balance principal in treating involutional entropion in the lower eyelid. A retrospective analysis of 47 patients (54 eyelids) diagnosed with involutional entropion in the lower eyelid and receiving tailored surgical treatment based on mechanical balance principle from 1 January 2016 to 31 December 2018 was carried out. Tailored surgical plans were developed according to the mechanical balance analysis of vertical, horizontal and sagittal directions. All 54 eyelids with involutional entropion in the lower eyelid underwent advancement of the lower eyelid retractor (LER) through the conjunctiva. For patients with mild horizontal eyelid laxity, only LER advancement was performed. For moderate and severe horizontal eyelid laxities, combined horizontal reinforcement procedures were performed, including lateral canthopexy, lateral tarsal strip (LTS) surgery and wedge resection. The orbicularis oculi muscle (OOM) tightening or transposition was performed for OOM overriding. The follow-up time was 1 to 4 years, and there were no cases experiencing recurrence. Thus, the rates of effectiveness and recurrence were 100% and 0%, respectively. This is the first descriptive study on the tailored surgical strategies designed according to the mechanism of mechanical imbalance involved in involutional entropion. Tailored surgery based on the mechanical balance principle is safe and effective with low recurrence.

Structural features of the temporomandibular joint in patients with gnathic mesial occlusion

The aim of the study was to evaluate the structural features of the temporomandibular joint in patients with a gnatic form of mesial occlusion of the dentition. Materials and methods. In studying the structural features of the facial skull in patients with gnatic mesial occlusion, the height of the condylar process was separately evaluated in the course of the study in order to avoid the incorrect measurement of the branch height in cases of degenerative changes in the condylar process. Results. The structural features of the temporomandibular joint were determined in 50 adult patients (aged 1844 years old) using cone-beam computed tomography.Сonclusion. Patients with gnathic mesial occlusion of the asymmetric group showed identical articular spaces (anterior and posterior) in the sagittal direction on both the deviating and non-deviating sides, suggesting that the bilateral relationship between the head and fossa may be as symmetrical as in patients with symmetry. However, the axial condylar angle had a bilateral difference only among patients in the asymmetric group; namely, it was significantly greater on the side of the deviating condyle.

Directional Dependence of Experimental Trunk Stiffness: Role of Muscle-Stiffness Variation of Nonneural Origin.

Trunk stiffness is an important parameter for trunk stability analysis and needs to be evaluated accurately. Discrepancies regarding the dependence of trunk stiffness on the direction of movement in the sagittal plane suggest inherent sources of error that require explanation. In contrast to the common assumption that the muscle stiffness remains constant prior to the induction of a reflex during position perturbations, it is postulated that muscle-stiffness changes of nonneural origin occur and alter the experimental trunk stiffness, causing it to depend on the sagittal direction. This is confirmed through reinterpretation of existing test data for a healthy subject, numerical simulation, and sensitivity analysis using a biomechanical model. The trunk stiffness is determined through a static approach (in forward and backward directions) and compared with the model stiffness for assumed scenarios involving deactivated muscles. The difference in stiffness between the opposite directions reaches 17.5% without a preload and decreases when a moderate vertical preload is applied. The increased muscle activation induced by preloads or electrical stimuli explains the apparent discrepancies observed in previous studies. The experimental stiffness invariably remains between low and high model-stiffness estimates based on extreme scenarios of the postulated losses of muscle activation, thereby confirming our hypothesis.

Base Curve of Progressive Addition Lenses Influences Clear Vision and Stereopsis Area.

PurposeProgressive addition lenses (PAL) are effective, particularly for middle-aged and elderly people who require reading spectacles. However, with PALs, peripheral vision may be distorted and blurred because of both the lateral bending of the surface and the effect of unequal bending of the light coming from an off-axis location in the tangential and sagittal directions, which may lead to a decrease in the quality of vision. Till date, no evaluation of PALs has been reported with regard to peripheral and binocular vision. We investigated the influence of high-base-curve PAL on the visual function of binocular vision using a synoptophore.MethodsThe subjects were seven males and 13 females aged 50–79 years with a best-corrected visual acuity of decimal visual acuity (1.0) or higher in both eyes and addition power of 1.50–2.50 diopters as the inclusion criteria. The study design was a two-group, two-period crossover trial. Using a synoptophore, the subjective clear vision area of monocular vision and stereopsis area of binocular vision were measured while wearing conventional-base curve PAL (4-curve) and high-base-curve PAL (8-curve). HOYALUX RF SPORT 1.6 lenses (HOYA Corporation, Tokyo, Japan) were used for the test PALs.ResultsThe clear vision area of monocular vision was significantly wider when wearing the 8-curve PAL on the temporal side of the right eye (P = 0.02), and on the temporal side of the left eye (P = 0.01). The stereopsis area of binocular vision was significantly wider in all directions when wearing the 8-curve PAL: right (P = 0.02); left (P = 0.03); right 15° upward (P = 0.02); and left 15° upward (P = 0.02).ConclusionIt was clarified that, compared to 4-curve PAL, clear vision and stereopsis areas are wider when wearing 8-curve PAL.

Quantitative X-ray Channel-Cut Crystal Diffraction Wavefront Metrology Using the Speckle Scanning Technique.

A speckle-based method for the X-ray crystal diffraction wavefront measurement is implemented, and the slope errors of channel-cut crystals with different surface characteristics are measured. The method uses a speckle scanning technique generated by a scattering membrane translated using a piezo motor to infer the deflection of X-rays from the crystals. The method provides a high angular sensitivity of the channel-cut crystal slopes in both the tangential and sagittal directions. The experimental results show that the slope error of different cutting and etching processes ranges from 0.25 to 2.98 μrad. Furthermore, the results of wavefront deformation are brought into the beamline for simulation. This method opens up possibilities for new high-resolution applications for X-ray crystal diffraction wavefront measurement and provides feedback to crystal manufacturers to improve channel-cut fabrication.

Morphometric analysis of in vitro human crystalline lenses using digital shadow photogrammetry

There is a great need for accurate biometric data on human lenses. To meet this, a compact tabletop optical comparator, the minishadowgraph, was built for measuring isolated eye lens shape and dimensions while the lens was fully immersed in supporting medium. The instrument was based around a specially designed cell and an illumination system which permitted image recording in both sagittal and equatorial (coronal) directions. Data were acquired with a digital camera and analyzed using a specially written MATLAB program as well as by manual measurements in image analysis software. The possible effect of lens orientation and gravity on the dimensions was examined by measuring dimensions with anterior or posterior surfaces up and by measuring lenses with calipers after removal from the minishadowgraph cell.Dimensions, curvatures and shape factors were obtained for 134 fully accommodated lenses ranging in age from birth to 88 years postnatal. Of these, 41 were from donors aged under 20 years, ages which are generally of limited availability. Thickness and diameter showed the same age-related trends described in previous studies but, for the lenses measured in air, age-dependent differences were observed in thickness (−5 to 0%) and diameter (+5 to 0%), consistent with gravitational sag. Anterior and posterior radii of curvature of the central 3 or 6 mm, depending on lens diameter, increase with age, with the anterior increase greater than the posterior. The anterior surface shape of the neonatal lens is that of a prolate ellipse and the posterior, an oblate ellipse. Both surfaces become hyperbolic after age 20.The data presented here on dimensions, shape and sagging will be of great value in assessing age-related changes in the optical and mechanical performance of the lens. In particular, the comprehensive data set from donors aged under 20 years provides a unique and valuable insight to the changes in size and shape during the early dynamic growth period of the lens.

Comparison of prognostic impact of anatomic location of the pancreas on postoperative pancreatic fistula in laparoscopic and open gastrectomy

BackgroundPostoperative pancreatic fistula (POPF) is a serious complication after gastric cancer surgery. The current study aimed to investigate the significance of the anatomic location of the pancreas as a predictor for POPF in both laparoscopic gastrectomy (LG) and open gastrectomy (OG).MethodsIn total, 233 patients with gastric cancer were assessed retrospectively. We measured the maximum vertical (P-L height; PLH) and horizontal length (P-L depth; PLD) between the upper border of pancreas and the root of left gastric artery on a preoperative CT in the sagittal direction. The maximum length of the vertical line between the surface of the pancreas and the aorta (P-A length), previously reported as prognostic factor of POPF, was also measured. We investigated the correlations between these parameters and the incidence of POPF in LG and OG groups.ResultsAmong the patients in this study, 118 underwent OG and 115 underwent LG. In LG, the median PLH and P-A length in patients with POPF were significantly longer compared with those without POPF (p = 0.026, 0.034, respectively), but not in OG. There was no significant difference in the median PLD between the patients with or without POPF in both LG and OG. The multivariate analysis demonstrated that PLH (odds ratio [OR] 4.19, 95% confidence interval [CI] 1.57–11.3, P = 0.004) and P-A length (OR 4.06, 95%CI 1.05–15.7, P = 0.042] were independent factors for predicting POPF in LG. However, intraoperative blood loss (OR 2.55, 95%CI 1.05–6.18, P = 0.038) was extracted as an independent factor in OG. The median amylase level in the drained fluid (D-Amy) were significantly higher in patients with high PLH(≥12.4 mm) or high P-A length (≥45 mm) compared with those with low PLH or low P-A length in LG. However, there were no differences in the D-Amy levels by PLH or P-A length in OG patients.ConclusionsThe anatomic location of the pancreas is a specific and independent predictor of POPF in LG but not in OG. PLH is a simple parameter that can evaluate the anatomic position of the pancreas, and it may be useful for preventing POPF after LG.

Changes of arch form at the end of orthodontic treatment, based on the Ricketts pentamorphic arch forms

Maintenance of the intercanine and intermolar distances reduces the risk of relapse and increases the chance of stability; these values represent the limits of the arch, resulting from the muscular balance of each patient. The ideal would be to reproduce the patient's arch form individually. The Ricketts pentamorphic arch forms allow the clinician to choose among 5 shapes, the one that best fits the patient's arch form. The objective of this study was to evaluate the effect of orthodontic treatment without extraction according to the pentamorphic arch forms on mandibular arches of different forms. Fifty patients were included in the study. For each patient, the pretreatment and end-of-treatment models were scanned by 3Shape Trios (3Shape, Copenhagen, Denmark) and transferred to the OrthoAnalyzer software (3Shape) version 2017-11.7.1.3 for measurements and superimpositions. The following measurements were made on the mandibular arches for both initial and final digitalmodels: arch depth; intercanine distance, the distance between the first premolars, the distance between the second premolars, the distance between the first molars, and the distance between the secondmolars. Three superimpositions were made: superimposition between the initial arch and the corresponding form of the pentamorphic arch forms, superimposition between the final arch and the corresponding form of the pentamorphic arch forms, and superimposition between the initial arch and the final arch. The largest difference between the superimposed arches in each region was measured. This study showed that intercanine distance (P=0.236), the distance between the first premolars (P=0.074), and the distance between the first molars (P=0.616) did not significantly change after orthodontic treatment. In contrast, the distance between the secondmolars (P=0.028) and the arch depth (P<0.001) increased significantly after orthodontic treatment. The mean of the largest difference in the absolute value of all the superimpositions is significantly different from the theoretical value 0 (P<0.001), but clinically, this difference is significant only in certain premolars and molars regions. This study has shown that the pentamorphic arch forms maintained the arch shape in the sagittal and transverse directions, except for an expansion of the distance between the mandibular secondmolars.