Topography of the location of mental foramen in dried edentulous human mandible and its clinical implication

The mental foramen is an oval or round opening on external surface of mandible and transmits mental nerve and vessels. Mostly located at apex of second mandibular premolar or between the apices of premolars. The study was commenced on 60 dried edentulous mandibles with the aim to determine location of mental foramen(MF) with reference to surrounding anatomical landmarks. By measuring its distance from midline (symphysis menti), posterior border of ramus of mandible, lower border of mandible. Length of lower border (Base) of mandible was also measured. In present study most common shape of mental foramen was round (70%). The mean distances of MF from midline are 24.36mm on right side and 24.15mm left side. From posterior border of ramus are 64.45mm on right side and 64.15mm on left side. From base of mandible are 12.29mm on right side and 12.48mm on left side. Length of base mandible (midline to angle of mandible) is 83.27mm right side and 83.12mm left side. Ratio of distance from symphysis menti to MF and length of base of mandible are same on both sides that are 0.29. There is statistically significant positive correlation between distance from symphysis menti to MF and length of base of mandible.The MF plays a very important role in treatment planning and its location needs to be considered prior to placement of dental-implants, regional anesthesia, osteotomy-surgeries and during complete denture-fabrication in order to avoid MN injury and related complications.

DYNAMIC ANALYSIS OF PLATES WITH CUT-OUT CARRYING CONCENTRATED AND DISTRIBUTED MASS

An isoparametric plate bending element with nine nodes is used in this paper for dynamic analysis of isotropic cut-out plate having concentrated and uniformly distributed mass on the plate. The Mindlin’s first-order shear deformation theory (FSDT) is used in the present finite element formulation. Two proportionate mass lumping schemes are used. The effect of rotary inertia is included in one of the mass lumping schemes in the present element formulation. Dynamic analysis of rectangular isotropic plates with cut-out having different side ratio, thickness ratio and boundary condition is analysed using a finite element method. The present results are compared with the published results. Some new results on isotropic plates with cut-out having different side ratio, ratio of side-to-thickness of the plate, different position and size of cut-out in plates subjected to transversely concentrated and distributed mass are presented.

Muscle volume evaluation using 3DCT for congenital clubfoot

Background In congenital clubfoot, the lower leg is very thin and the calf muscles are hypoplasic. However, there are few studies reporting real muscle volume. Purpose The purpose of this study is to assay the muscle volume in congenital clubfoot using 3DCT and to quantify the degree of the hypoplasia. Material and methods From January 2015 to December 2016, nine consecutive patients, seven male and two female, with unilateral congenital clubfeet were recruited for CT scans. Axial transverse sectional CT scans were acquired from the delineation of the fibular head to the tibial plafond. From the data, we rendered the entire muscle in 3D for muscle volume assay, and further segmented the posterior musculature for comparison between the normal and affected sides. Results The whole muscle volume on the normal side was 291.23 cm3 (181.23–593.49) and that on the affected side was 225.08 cm3 (120.71–429.08), for an affected side to normal side ratio of 0.79 (0.72–0.9), which was significantly smaller ( p < .01). Posterior muscle volume on the normal side was 175.81 cm3 (103.72–376.32) and that on the affected side was 106.52 cm3 (58.3–188.39). The ratio of posterior muscle to whole muscle on the normal side was 0.62 (0.46–0.75), and that on the affected side was 0.48 (0.4–0.55), such that the affected side was significantly smaller ( p < .01) Conclusion This study contributes quantitative data supporting the longstanding observations that the posterior calf muscles are significantly smaller on the affected side compared to the normal side in congenital clubfoot, and further underscores the importance of the extending the excursion of these muscles.

Investigation of the forming behavior of carbon fiber yarns on microscopic scale with detailed statistical volume elements

Simulations at microscopic scale are subject of research in many fields of continuous fiber reinforced materials. They allow the virtual characterization with clearly defined boundary conditions and the investigation of effects that cannot easily be observed in experimental tests, such as crack initiation. While the influence of differently detailed modeling, such as variable fiber radii, is well investigated for consolidated composite materials, that influence is not well investigated for dry yarns. The effect of different modeling aspects on the shearing of statistical volume elements (SVE) is object of this study. Those aspects are in particular the SVE’s size and side ratio, the deformation velocity, the friction coefficient and the initial stress of the elements. The investigations have shown that the deformation of the SVEs is very sensitive to changes of the named parameters. Especially parameters that influence the number of fiber contacts or the friction forces have a noticeable effect on the shear stress. In addition, changes in the velocity have a significant impact on the deformation. Therefore, it is necessary to characterize the fiber and yarn parameters precisely and transfer them into the simulation model to obtain a realistic deformation behavior.

Long-term outcomes of metacarpal fractures surgically treated using bioabsorbable plates: a retrospective study

Background Implants made from bioabsorbable unsintered hydroxyapatite and poly-L-lactate composites (u-HA/PLLA) are widely used in the oral, maxillofacial, and orthopedic fields. This study assess the long-term (> 5 years) outcomes of patients with metacarpal fractures who were surgically treated using bioabsorbable plates and screws (Super-Fixsorb MX40 mesh; Teijin Medical Technology, Osaka, Japan). Methods A retrospective analysis of six patients with eight metacarpal fractures treated with bioabsorbable plates was done. All patients were followed for more than 5 years post-surgery. The clinical outcomes were evaluated using Q-DASH scores and the grip strength (GS): opposite side ratio. The resorption status of implants was assessed on plain computed tomography (CT) scans at final follow-up appointments. Results The mean age of the patients at the time of surgery was 29.5 years (16–54), and the median follow-up period was 81.8 months (68–101). All fractures united without displacement after an average of 3.5 months, and there were no implant specific complications associated with the use of absorbable plates. The mean grip strength ratio was 85.1% (56.8–104.5). The mean Q-DASH scores of 11.36 points (0–34.09) was good in all but two patients. We also observed that it took more than 8 years for the plates to be absorbed completely. Conclusions This study demonstrates that the process of bioabsorption in metacarpal fractures might be completed in about 8 years, and the absorption speeds were different inside and outside of the bone. The bioabsorbable plates are more cost-effective than metallic implants. The potential for bioabsorbable plates to be used in various clinical procedures is promising.