為保留較多的角質化牙齦(keratinized gingiva),當手術暴露上顎犬齒頰側阻生時,下列那些是較為適當的方法?①開窗術暴露(window open) ②根向移位翻瓣術(apically positioned flap) ③側向移位翻瓣術(laterally positioned flap)
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