Study on detection of lumps in a soft object by using a scanning roller type palpation sensor system

In this study, a palpation sensor system is developed to detect a lump in a soft object. The developed sensor system consists of a contact part using a bearing, two linear sliders and a 3-axis load cell. While the roller type contact part is scanned against a soft object, reaction force applied to the contact part is measured. Lumps are detected by measuring fluctuation of the reaction force. In experiments, the sensor system is scanned against the samples. From the results, it is found that the lump with a small diameter embedded at a deep position.

Relationship between the Position of Impacted Third Molars and External Root Resorption of Adjacent Second Molars: A Retrospective CBCT Study

Background and objectives: Impacted third molars (ITM) are the most commonly-impacted teeth. There is a risk for ITM to cause a number of pathological conditions, and external root resorption (ERR) of adjacent teeth is one of the most prevalent. Retaining or prophylactic extraction of ITM is a polemic topic. External root resorption of adjacent teeth is one of possible indications for prophylactic removal of ITM. The aim of this study was to assess the relationship between external root resorption (ERR) on the distal aspect of second molars’ roots and positional parameters of ITM. Methods: Cone beam computed tomography scans of 109 patients (41 males, 68 females; mean age 26.4 ± 7.9 years) with 254 ITM (131 in the maxilla and 123 in the mandible) were retrospectively analyzed. Positional parameters of ITM (mesio-distal position, angulation, impaction depth, and available eruption space) were evaluated. The presence, location, and depth of ERR of adjacent second molars were assessed. Results: Analysis showed a relationship between ITM impaction depth, mesial inclination angle, and the presence of ERR. Mesial inclination angle of more than 13.6° increased the odds of ERR occurrence by 5.439 (95% CI, 2.97–9.98). ITM presence at the level of ½ of roots of the adjacent second molar or more apically increased the odds of ERR occurrence by 2.218 (95% CI, 1.215–4.048). No significant correlation was detected between the occurrence of ERR and patient age, gender, or the available eruption space in the mandible. Depth of ERR did not depend on its location. Conclusions: Incidence of ERR in second molars is significantly associated with mesial inclination and a deep position of ITM.

Isolated Sphenoid Sinus Lesions: Experience with a Few Rare Pathologies

ABSTRACT Introduction: The sphenoid sinus is often neglected because of its difficult access. The deep position of the sphenoid sinus hinders early diagnosis of pathologies in that location. Delayed diagnosis can cause serious complications due to proximity to many important structures. Objectives: The aim of this study is to demonstrate different pathologies which can affect the sphenoid sinus and elucidate the findings. Methods: Cases of isolated sphenoid sinus lesions encountered in the neurosurgical setting which had rare pathologies are discussed. Pathologies such as Langerhans cell histiocytosis, solitary plasmacytoma, chordoma, pituitary adenoma, leiomyosarcoma, fungal infection, and mucocele which appeared primarily in sphenoid sinus are discussed along with their imaging features and pathological findings. Conclusion: Multitude of different pathologies can occur in sphenoid sinus. Detailed preoperative imaging is very helpful, but transnasal biopsy and histological study are required often for definitive diagnosis. The possible advantages of early diagnosis before spread of pathology for prognosis cannot be overemphasized.

Numerical Analysis of Texture Tactics on Skin by Using of the Model of Periodic Micro Unit

Various mechanical effects occur in the human skin when it touches the texture which has micrometric scale. Since these mechanical effects in the skin are complicated, their study is necessary. The purpose of this study is to ascertain these mechanical effects by applying numerical analyses for a detailed discussion. In particular, the analysis confirms the differential effects in the skin due to a periodic variation of the texture. By the modeling situation that the texture touches the skin, a stress in the position of skin sensory organs is examined. As a result of the analysis, von Mises stresses at a shallow position of skin showed characteristic effects in the case of a large texture period. It is inferred that these effects occur with a texture period greater than a certain boundary value. Stress values at deep positions of skin are substantially equal without depending on the pressure position of the skin surface. In other words, skin sensory organs of the deep position have a wide receptive field in the numerical analysis of this paper, and this result matches with results of previous researches.