In this study, the damping mechanism at the interface of the mating spur gear teeth is investigated. The dynamic behaviour of a spur gear pair is represented by a two Degree-of-Freedom (DOF) nonlinear model with the damping provided by the instantaneous tribological behaviour of the tooth contacts. The shear stress distributions along the tooth surfaces are incorporated with the dynamic model t...

Abrasion is the physical wearing of a tooth surface which can involve the presence of a foreign object repeatedly being in contact with the tooth. A 40-year-old male patient reported to our dental clinic with a 2-3 mm uneven gap between his upper and lower front teeth on occlusion. A detailed history revealed that he was a physical education teacher, and the habitual placement of the whistle fo...

Paresthesia of the lower lip is uncommon during orthodontic treatment. In the present case, paresthesia occurred during orthodontic leveling of an extruded mandibular left second molar. It was decided to remove this tooth from the appliance and allow it to relapse. A reanatomization was then performed by grinding. The causes and treatment options of this rare disorder are reviewed and discussed...

statement of the problem in recent years, amalgam has been considered a danger for dentistry personnel due to toxicity of mercury (hg) purpose this study aimed at investigating the relationship between scientific indices and dentists’ urine hg level through measuring its concentration rate among dentists with over four years of experience materials and methods thirty dentists with over four yea...

OBJECTIVES The maintenance of the healthy periodontal ligament cells of the root surface of donor tooth and intimate surface contact between the donor tooth and the recipient bone are the key factors for successful tooth transplantation. In order to achieve these purposes, a duplicated donor tooth model can be utilized to reduce the extra-oral time using the computer-aided rapid prototyping (CA...

To improve the meshing performance and increase bearing capacity service life of spiral gear pairs, a cutterhead approximation machining method based on controlling geometric topological deviations was proposed to solve problem where line contact bevel gears with tapered teeth depth cannot be machined by cutterheads. First, mathematical model conjugate flank established, comparison between toot...

Dental materials based on Portland cement, which is used in the construction industry have gained popularity for clinical use due to their hydraulic properties, the interaction with tooth tissue and their antimicrobial properties. The antimicrobial properties are optimal in vitro. However in clinical use contact with blood may affect the antimicrobial properties. This study aims to assess wheth...

Lead screws are the most commonly used transmission components in tool machinery and precision machinery, widely various industrial equipment instruments. However, screw tooth profile squeezes friction causes gear to break, surface wear, pitting other damage, which reduces service life of screw; use a large amount lubricants can not ignore environmental impact. The design research this subject ...

Abstract The flank load carrying capacity of bevel and hypoid gears is mainly limited by the failure modes pitting, scuffing, tooth fracture phenomenon micropitting. By application a standardized calculation method, e.g. according to international standard ISO 10300:2014, first estimation can be made based on macro geometry or gear set. According method B 10300:2014 complexity real reduced virt...