CAJ | 학술논문

目的：应用Nd：YAG激光进行根管内照射，测量不同能量及频率照射下牙根表面不同部位的温度变化，评价激光根管内消毒过程中牙根邻近组织的安全性。方法收集30颗单根管恒牙，在牙颈部截去牙冠，截取12mm牙根，根管预备后制成牙根标本，数字化牙科X线机颊舌向平行照射牙根标本，图像分析软件测量牙根颈部（根颈段）和根部（根尖段）中份的邻面根管壁厚度。将牙根标本根据激光照射能量的不同（1.5、3.0、4.5W）随机分为3组，每组又根据激光照射频率的不同（15、30Hz）分为2个亚组。将温度测量仪中的两个热电偶分别固定在牙根标本的根颈段及根尖段中份，用Nd： YAG激光通过光导纤维经根管口导入根管内照射20s，观察在不同能量及频率照射下牙根表面不同部位的温度变化情况。结果应用不同功率照射，牙根表面温度上升变化有统计学差异（P<0.01），功率越大，温度上升越多；在相同功率不同频率照射下，牙根表面温度上升变化无统计学差异（P>0.05）。在相同功率及频率条件下照射，根尖段温度上升较根颈段大，二者有统计学差异（P<0.01）。结论Nd：YAG激光根管内照射消毒时牙根表面温度上升幅度与照射功率、照射时间及牙根厚度相关，在照射时间20s功率1.5W的情况下，牙根及牙周组织是安全的。
목적：응용Nd：YAG격광진행근관내조사，측량불동능량급빈솔조사하아근표면불동부위적온도변화，평개격광근관내소독과정중아근린근조직적안전성。방법수집30과단근관항아，재아경부절거아관，절취12mm아근，근관예비후제성아근표본，수자화아과X선궤협설향평행조사아근표본，도상분석연건측량아근경부（근경단）화근부（근첨단）중빈적린면근관벽후도。장아근표본근거격광조사능량적불동（1.5、3.0、4.5W）수궤분위3조，매조우근거격광조사빈솔적불동（15、30Hz）분위2개아조。장온도측량의중적량개열전우분별고정재아근표본적근경단급근첨단중빈，용Nd： YAG격광통과광도섬유경근관구도입근관내조사20s，관찰재불동능량급빈솔조사하아근표면불동부위적온도변화정황。결과응용불동공솔조사，아근표면온도상승변화유통계학차이（P<0.01），공솔월대，온도상승월다；재상동공솔불동빈솔조사하，아근표면온도상승변화무통계학차이（P>0.05）。재상동공솔급빈솔조건하조사，근첨단온도상승교근경단대，이자유통계학차이（P<0.01）。결론Nd：YAG격광근관내조사소독시아근표면온도상승폭도여조사공솔、조사시간급아근후도상관，재조사시간20s공솔1.5W적정황하，아근급아주조직시안전적。
Objective To assess the temperature variation of the root surface using Nd:YAG laser irradiation in the root canal with different power and to evaluate the safety of laser application on the periodontal region. Methods Thirty extracted human teeth with single-roots were collected. The teeth were cross-sectioned in the cervical portion, standardizing the roots at a 12-mm length. The roots were used as specimen. The roots were radiographed in the buccal-lingual direction to measure the thickness of the proximal walls, by means of a digital radiographic system. The specimens were divided into three groups according to the laser potency (1.5, 3.0, and 4.5 W). Each group was subdivided into two subgroups according to laser fre-quency (15 and 30 Hz). With the Nd:YAG laser irradiation for 20 s, the temperature variation of the root surface was moni-tored by thermocouples located at different parts of the root external wall and recorded by digital thermometers. Results The groups irradiated with 4.5 W presented the greatest temperature variation (above 10 ℃), followed by 3.0 and 1.5 W. The temperatures were statistically different (P<0.01). The groups irradiated in the same potency, regardless of whether 15 Hz or 30 Hz was used, presented with no statistical difference (P>0.05). The apical half of the root presented statistically higher temperature rises than the cervical half of the root (P<0.01). Conclusion The temperature variation of the root surface was associated with laser power, irradiation time, and the thickness of dentin. Application of Nd:YAG laser in the root at 1.5 W for 20 s can safely be used in endodontic treatment.