This study emphasizes the warpage phenomenon of thin-walled parts using acrylonitrile-butadiene styrene (ABS) plus polycarbonate (PC) plastics for optimal processing by thin-wall injection molding. The authors first employed the Moldflow software to analyze the runner’s balance on multicavities for thin-walled parts and to simulate the warpage of thin-walled parts with thin-wall injection molding. Then, this study used those data to fabricate a real mold by computer numerical control machining. For this study, the authors fabricated thin-walled parts and measured their warpage using various process parameters (injection speed, injection pressure, mold temperature, packing time, and melt temperature) with thin-walled injection molding. Finally, the authors found that the most important processing parameter was the packing time for warpage phenomenon of thin-walled parts by thin-wall injection molding.

Clarification of potential factors affecting the occurrence of accidental sharps injuries among students in dental laboratories would likely help to reduce the incidence of such injuries, thus improving dental education, as well as further preventing injury in general healthcare workspaces. In this study, undergraduates at the College of Oral Medicine, Taipei Medical University, were assessed for 10 items: gender, age, course specialty, whether or not framed glasses were worn during operations, speed of assignment completion, dominant hand, self-assessment of performance, whether or not students previewed the classes in advance, sleep duration, and sharps injury experience. The results suggested that course specialty and sleep duration were the major factors associated with the occurrence of sharps injuries among students in the dental laboratory.

PurposeTo analyze differences in smile parameters following surgical-orthodontics in skeletal Class III patients with mandibular prognathism and to identify factors affecting smile parameters after orthognathic surgery.Materials and Methods:These retrospective study comprised of thirty-four patients, diagnosed as having skeletal Class III malocclusion with pure mandible prognathism, were treated with surgical-orthodontics in Taipei Medical University Hospital. Hard and soft tissue variables were measured through lateral cephalometry, and smile esthetics were measured using extraoral photographs. Postoperative changes in smile parameters and differences between sexes were analyzed using the t test. The relationship among smile parameters were analyzed using the Pearson correlation. Random forest methods and decision tree deep learning models were used to identify the variables associated with asymmetry after surgery.Results:Postoperatively, the buccal corridor (p = 0.024), upper lip height (C1) (p = 0.003), and smile index (p = 0.031) were significantly different. The upper midline and right chelion were significantly different between sexes. A very strong positive correlation was observed between the upper lip height and upper lip ratio and between the lower lip height and lower lip ratio; a strong positive correlation was observed between lower teeth exposure and the interlabial gap and between the right chelion and left chelion. By contrast, a strong negative correlation was observed between lower teeth exposure and the smile index and between the smile index and interlabial gap. The following smile parameters associated with asymmetry exhibited the most changes after surgery: lower lip area, interlabial gap, smile index, buccal corridor, and arc ratio.Conclusions:Following orthognathic surgery, marked changes were noted in skeletal, dental, and soft tissue parameters, but smile esthetics changed less from the frontal view. The most changes regarding asymmetry after surgery were noted in the lower lip area, interlabial gap, smile index, buccal corridor, and arc ratio in this order.