Objectives: At present, removable partial denture is still one of the main restoration methods for dentition defects. However, the trend for digital partial denture is becoming more and more obvious in the field of oral repair. However, there are relatively few studies on digital removable partial denture. The aim of this study is to investigate the effects of 3 processing technologies (precision casting, digital cutting, and 3D printing) on the fitness for the clasps of cobalt chromium alloy and pure titanium removable partial denture, and to provide a theoretical basis for the clinical application of digital removable partial denture.
Methods: Clasps of Co-Cr alloy and pure titanium were produced by 3 different processing technologies (precision casting, digital cutting, and 3D printing). There are 6 groups, including a casting pure titanium group, a casting cobalt chromium group, a cutting pure titanium group, a cutting cobalt chromium group, a printing pure titanium group, and a printing cobalt chromium group (n=6 per group). The gaps between the initial, middle, and tip of the lingual opposing arm of the clasp and the abutment were measured by fluorescent microscope, and the average value was taken as the index to measure the fitness between the clasp and the abutment. The fitness difference in three-arm clasp made of cobalt chromium alloy and pure titanium materials under 3 different technologies was compared.
Results: There was no statistical difference in fitness between the casting pure titanium group and the casting cobalt chromium group (P>0.05); there was no statistical difference in fitness between the cutting pure titanium group and the cutting cobalt chromium group (P>0.05); there was no statistical difference in fitness between the printing pure titanium group and the printing cobalt chromium group (P>0.05). When pure titanium was used, the fitness of the printing pure titanium group was the best (both P<0.05). There was no significant difference between the casting pure titanium group and the cutting pure titanium group (P>0.05). When cobalt chromium alloy was used, there was no significant difference in fitness among the 3 groups (P>0.05).
Conclusions: The cobalt chromium alloy and pure titanium clasps made by precision casting, digital cutting, and 3D printing have good fitness. Under the same process, there is no significant difference between cobalt chromium alloy and pure titanium clasps. The 3D printing pure titanium clasps have better fitness than casting pure titanium and cutting pure titanium clasps, which meet the needs of clinical application.
目的: 可摘局部义齿目前仍是牙列缺损的主要修复方式之一。虽然数字化技术越来越多地应用于口腔修复领域，但是数字化可摘局部义齿的研究相对较少。本研究探讨精密铸造、数字化切削和3D打印3种加工工艺对钴铬合金、纯钛材料可摘局部义齿三臂卡环密合性的影响，以期为数字化可摘局部义齿修复的临床应用提供理论依据。方法: 设计并制作卡环标准试件，分别利用精密铸造、数字化切削、3D打印3种加工工艺制作钴铬合金、纯钛材料三臂卡环，设铸造纯钛组、铸造钴铬组、切削纯钛组、切削钴铬组、打印纯钛组及打印钴铬组6个组(n=6)。利用体式荧光显微镜测量卡环舌侧对抗臂的起始部、中部、尖端处与基牙的间隙，取其平均值作为衡量卡环与基牙密合性的指标。比较3种加工工艺制作钴铬合金、纯钛材料三臂卡环的密合性。结果: 铸造纯钛组与铸造钴铬组，切削纯钛组与切削钴铬组，打印纯钛组与打印钴铬组之间卡环密合性的差异均无统计学意义(均P>0.05)。在使用纯钛时，打印纯钛组卡环密合性最好，与其他2组比较差异均有统计学意义(均P<0.05)，铸造纯钛组与切削纯钛组密合性比较差异无统计学意义(P>0.05)；在使用钴铬合金时，3组间卡环密合性比较差异无统计学意义(P>0.05)。结论: 精密铸造、数字化切削和3D打印3种加工工艺制作的钴铬合金及纯钛卡环均具有良好的密合性，相同加工工艺下钴铬合金与纯钛材料金属卡环密合性无明显差异，3D打印的纯钛卡环相比于铸造纯钛及切削纯钛卡环具有更好的密合性，符合临床应用需求。.
Keywords: 3D printing; clasps; digital cutting; fitness; metal materials; precision casting.