エナメル質の高速研削における材料除去および表面損傷

Material removal and surface damage in high-speed grinding of enamel.

抄録

エナメル質表面の高速研削は、修復歯科治療においてしばしば必要とされるが、この加工に関連する研削力学、材料除去および破壊損傷メカニズムに関する知識はまだ比較的限られており、関連する科学的および理論的研究を行うことは重要である。そこで、歯の咬合面および頬・舌面を対象として、ダイヤモンド研削バーを用いたエナメル質表面の高速研削の実験スキームを設計し、研削力、力比、研削温度、切粉、表面形態、表面損傷、およびその他の重要な特性を試験および分析した。さらに、エナメル表面の高速研削に関連する研削形状モデル、研削力学、材料破壊、除去機構を検討した。その結果，頬・舌面研削で得られる研削力，摩擦係数，研削温度，表面損傷は，同じ研削条件で咬合面研削で得られるものよりかなり大きく，研削品質は悪いことがわかった．送り速度の増加に伴い，研削力，摩擦係数，研削温度および表面損傷は明らかに増加し，表面品質は低下する．エナメル質の高速研削過程では，脆化効果とアイアニング機構が存在する。送り速度に関係なく、頬・舌面の3種類の材料破壊モードは、咬合面のそれよりも深刻であり（不安定な大欠けや引き裂き欠けを生じやすくなる）、さらに、最終加工面の脆性破壊と損傷がより明白である。本研究で明らかになった切削力学と切削機構は、歯科用研削加工に科学的な指針を与えるだろう。

Although high-speed grinding of the enamel surface is often required in restorative dentistry, the knowledge of grinding mechanics, material removal, and fracture damage mechanism related to this process is still relatively limited; therefore, it is important to perform relevant scientific and theoretical research. As per the occlusal surface and the buccal/lingual surface of the teeth, the experimental scheme of high-speed grinding of the enamel surface using a diamond grinding bur was designed, and the grinding force, force ratio, grinding temperature, chips, surface morphology, surface damage, and other important characteristics were tested and analyzed. Furthermore, the grinding geometry model, grinding mechanics, material fracture, and removal mechanism associated with the high-speed grinding of an enamel surface were considered. The results show that the grinding force, friction coefficient, grinding temperature, and surface damage achieved through buccal/lingual surface grinding are considerably greater, and the grinding quality is worse than that obtained via occlusal surface grinding under the same grinding conditions. With the increase in the feed rate, grinding force, friction coefficient, grinding temperature, and surface damage obviously increase, and the surface quality decreases. The embrittlement effect and the ironing mechanism are present during the process of high-speed grinding of enamel. Regardless of the feed rate, the three types of material fracture modes of the buccal/lingual surface are more serious than those of the occlusal surface (making it more likely to produce unstable large chips or tearing chips); moreover, the brittle fracture and damage of the final machined surface are more obvious. The cutting mechanics and cutting mechanism identified in this study will provide scientific guidance for dental grinding operations.