Discipline of Endodontics, Department of Esthetic Dentistry, School of Dentistry, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
J Endod. 2011 Sep;37(9):1197-200. doi: 10.1016/j.joen.2011.05.038. Epub 2011 Jul 16.
The aim of this study was to evaluate pulp oxygenation levels (%SpO(2)) in patients with malignant intraoral and oropharyngeal tumors treated by radiotherapy (RT).
Pulp oxygenation levels were measured by pulse oximetry. Twenty patients were selected, and two teeth of each participant (n = 40) were analyzed, regardless of the quadrant and the area irradiated, at four different time points: TP1, before RT; TP2, at the beginning of RT with radiation doses between 30 and 35 Gy; TP3, at the end of RT with radiation doses between 60 and 70 Gy; and TP4, 4 to 5 months after the beginning of cancer treatment.
Mean %SpO(2) at the different time points were 93% (TP1), 83% (TP2), 77% (TP3), and 85% (TP4). The Student's t test showed statistically significant differences between TP1 and TP2 (P < .01), TP3 (P < .01), and TP4 (P < .01). TP3 was also statistically significantly different when compared with TP2 (P < .01) and TP4 (P < .01). No statistically significant difference could be observed between TP2 and TP4.
Because the mean %SpO(2) before RT was greater than during and after therapy and values obtained 4 to 5 months after the beginning of RT were close to the initiation of RT, pulp tissue may be able to regain normal blood flow after RT. If the changes in the microcirculation of the dental pulp were indeed transitory, preventive endodontic treatment or extraction in patients who are currently undergoing or recently received RT and who show negative signs of pulp sensitivity may not be necessary for pulpal reasons.
本研究旨在评估接受放疗（RT）治疗的恶性口腔和口咽肿瘤患者的牙髓氧合水平（%SpO(2)）。
通过脉搏血氧仪测量牙髓氧合水平。选择了 20 名患者，每位患者的两颗牙齿（n=40）无论象限和照射区域如何，在四个不同时间点进行分析：TP1，在 RT 之前；TP2，在 RT 开始时，辐射剂量为 30 至 35 Gy；TP3，在 RT 结束时，辐射剂量为 60 至 70 Gy；TP4，在癌症治疗开始后 4 至 5 个月。
不同时间点的平均%SpO(2)分别为 93%（TP1）、83%（TP2）、77%（TP3）和 85%（TP4）。学生 t 检验显示 TP1 与 TP2（P<.01）、TP3（P<.01）和 TP4（P<.01）之间存在统计学显著差异。TP3 与 TP2（P<.01）和 TP4（P<.01）之间也存在统计学显著差异。TP2 与 TP4 之间无统计学显著差异。
由于 RT 前的平均%SpO(2)大于治疗中和治疗后的%SpO(2)，并且 RT 开始后 4 至 5 个月获得的数值接近 RT 开始时的值，因此牙髓组织在 RT 后可能能够恢复正常血流。如果牙髓微血管的变化确实是暂时的，那么对于目前正在接受或最近接受 RT 且牙髓敏感呈阴性迹象的患者，出于牙髓原因，可能不需要进行预防性根管治疗或拔牙。
