Disclosed is a dental handpiece wherein the chip air line is selectively switched to the ON-state for using both water and chip air, and to the OFF-state for using only water. The dental handpiece has a switching valve provided between the circumferential chip air channel and the chip air line in the handpiece body for selectively allowing and preventing communication therebetween, wherein opening of the valve switches the communication to the ON-state in which chip air is allowed to pass from the circumferential chip air channel into the chip air line, whereas closing of the valve switches the communication to an OFF-state in which chip air is prevented from passing from the circumferential chip air channel into the chip air line.茲揭示一種齒科用手持機,其中,沖屑空氣管線被選擇性切換至供使用水及沖屑空氣兩者之導通狀態,及供僅使用水之切斷狀態。齒科用手持機具有切換閥,設在周邊沖屑空氣通道與手持機本體中的沖屑空氣管線之間,供選擇性容許及防止其間之連通,其中,閥之開啟將連通切換至導通狀態,其中,沖屑空氣被容許從周圍沖屑空氣通道進入沖屑空氣管線,而閥之關閉則將連通切換至切斷狀態,其中,沖屑空氣被防止從周圍沖屑空氣通道進入沖屑空氣管線。P‧‧‧齒科用手持機2‧‧‧手持機本體20‧‧‧軸向膛孔200‧‧‧開口201‧‧‧水管線202‧‧‧沖屑空氣管線21‧‧‧外殼210‧‧‧管狀連接器22‧‧‧圓周水通道23‧‧‧圓周沖屑空氣通道24‧‧‧連接端口25‧‧‧連接端口26‧‧‧頭部4‧‧‧切換閥5‧‧‧閥座孔
