目的:為了保留更多的健康牙柚質並增加初期輔齒病仕區的抗酸侵蝕能力，在本實驗中使用CO2雷射、Nd:YAG雷射與氣化物來處理初期輔齒並比較其效果。 材料與方法120個取自人類無攝齒病姓之小臼齒的牙齒樣本， 將其浸泡於酸鹼循環溶液中2天以形成初期攝齒病仕區。隨機將所有樣本分成4組:控制組、CO2雷射組、Nd:YAG雷射組與APF組;各組別再依據該組條件進行 雷射或氣化物的處理。接下來將所有牙齒樣本再次浸泡入酸鹼循環溶液中2天進行酸侵蝕，利用ISE-trol®分析溶液中由牙柚質表面溶解出來的鈣離子，以評估各組之抗酸侵蝕能力的差異。同時利用掃瞄式電子顯微鏡與X光繞射來分析牙柚質表面型態的改變與組成結構的成分。
結果:在鈣離子溶出分析以評估抗酸侵蝕能力方面，控制組較其他組別有較高的鈣離子溶出濃度並在統計上有顯著差異(P<0.05)。此外APF組較兩雷射組有較高的鈣離子溶出濃度，在統計學上亦呈現出顯著差異(P<0.05) ，但在CO2雷射組與Nd:YAG雷射組間則無顯著差異出現(P>0.05)。從掃瞄式電子顯微鏡上觀察可見在CO2雷射組與Nd:YAG雷射組的牙柚質表面，出現熔融再結晶的現象及直徑1-20μm類似火山口狀的坑洞。最後經由X光繞射分析，無論是雷射組別或是APF組別的牙柚質表面皆無發現新的組成成分。
結論:在具有初期騙齒的牙柚質表面使用CO2雷射、Nd:YAG雷射及APF皆可增加其抗酸侵蝕能力，就效果而言雷射較APF有更佳的表現。

Objectives :In order to preserve the maximum amount of healthy enamel and increase the acid resistance of an incipient carious lesion， CO2 laser， Nd:YAG laser and APF were used to treat incipient carious lesions， then their effects were compared.
Materials and Methods :One hundred and twenty samples from human caries-free premolars were immersed in pHcycling solution for 2 days for incipient carious lesion formation. Then all the samples were divided into 4 groups randomly; control group， CO2 laser group， Nd:YAG laser group and APF group， and the lesions were treated by CO2 laser， Nd:YAG laser irradiation or APF application respectively. All the samples were immersed in pH-cycling solution a second time for 2 days. As for the acid-resistance evaluation， the calcium concentration dissolved from the enamel surface was analyzed by ISE-trol. Scanning electron microscopy with energy dispersive X-ray analysis system was also used to assay the geographic change and the components of the enamel surface structures.
Results :According to the acid-resistance evaluation， the control group showed a statistically significant (P<0.05) higher calcium concentration compared with the APF group and the other two laser groups. Moreover， the APF group showed a statistically significant higher calcium concentration compared with the Nd:YAG laser and CO2 laser groups (P<0.05). However， there was no substantial statistical difference in the two laser groups (P>0.05). From the SEM， the melting and re-crystallization surfaces and crater-like holes， 1-20μm in diameter， were found on the CO2 laser and Nd:YAG laser treated enamel surfaces. Finally， in the aspect of the EDS， there was no evidence of new components on the enamel surfaces after lasers and APF were applied.
The application of CO2 laser， Nd:YAG laser andAPF on enamel incipient carious lesions increase acid resistance. Furthermore， the effect of laser irradiation is better than that of APF application.