Am J Orthod Dentofacial Orthop. 2010 Feb;137(2):254-8. doi: 10.1016/j.ajodo.2008.04.023.
Although it has been suggested that orthodontic treatment might lead to changes in the dental pulp, no clinical study has attempted to investigate the incidence of pulp necrosis after orthodontic therapy. The purpose of this clinical trial was to determine whether pulp testing response is altered after rapid palatal expansion (RPE).
Twenty-five adolescent patients (9 boys, 16 girls; ages, 10-16 years) participated in the study. A hyrax appliance was cemented on the first permanent molars and first premolars (when fully erupted). The appliance was activated twice daily (0.5 mm) for 2 weeks. An electric pulp tester (EPT) was used to test at the buccal cusp tips of the molars and premolars. Teeth that did not respond to the EPT were subsequently tested thermally with Endo Ice (Hygienic Corporation, Akron, Ohio).
All maxillary molars and erupted premolars of the 25 patients responded positively to pulp tests before cementation of the hyrax appliance. Of the 49 molars tested, 46 responded positively to the EPT, and 3 responded positively to the cold testing (CT). Of the 42 first premolars tested, 40 responded positively to the EPT and 2 to the CT. Of the 38 second premolars tested, 35 responded positively to the EPT and 3 to the CT. Two weeks after the initial activation of the hyrax appliance, 93 teeth in 17 subjects were tested. Of the 93 teeth, 73 teeth responded positively to the EPT and 20 to the CT. Three to 6 weeks after hyrax activation was discontinued, 59 teeth were tested; 48 tested positively to the EPT and 10 to the CT. One tooth (maxillary left first molar) did not respond to either EPT or CT. Finally, 3 to 9 months into retention, all molars and premolars of 23 subjects tested positive to pulp tests, 92 teeth to the EPT and 25 to the CT. The maxillary left first molar that had not responded to the tests at the 3-to-6 week check responded positively to the CT at the final check.
After RPE therapy in children and adolescents, the pulp of the posterior permanent teeth examined in this study was vital.
虽然有人认为正畸治疗可能会导致牙髓变化，但尚无临床研究试图调查正畸治疗后牙髓坏死的发生率。本临床试验的目的是确定快速腭扩张（RPE）后牙髓测试反应是否改变。
25 名青少年患者（9 名男孩，16 名女孩；年龄 10-16 岁）参与了这项研究。在第一恒磨牙和第一前磨牙（完全萌出时）上粘固 Hyrax 矫治器。矫治器每天两次（0.5 毫米）激活 2 周。使用牙髓电活力测试仪（EPT）测试磨牙和前磨牙颊尖。对 EPT 无反应的牙齿随后用 Endo Ice（Hygienic Corporation，Akron，Ohio）进行热测试。
所有上颌磨牙和 25 例患者上颌前磨牙在 Hyrax 矫治器粘固前均对牙髓测试呈阳性反应。在 49 颗磨牙中，46 颗对 EPT 呈阳性反应，3 颗对冷测试（CT）呈阳性反应。在 42 颗第一前磨牙中，40 颗对 EPT 呈阳性反应，2 颗对 CT 呈阳性反应。在 38 颗第二前磨牙中，35 颗对 EPT 呈阳性反应，3 颗对 CT 呈阳性反应。Hyrax 矫治器初始激活后 2 周，对 17 名受试者的 93 颗牙齿进行了测试。在 93 颗牙齿中，73 颗牙齿对 EPT 呈阳性反应，20 颗牙齿对 CT 呈阳性反应。Hyrax 激活停止后 3-6 周，对 59 颗牙齿进行了测试；48 颗牙齿对 EPT 呈阳性反应，10 颗牙齿对 CT 呈阳性反应。一颗牙齿（上颌左侧第一磨牙）对 EPT 和 CT 均无反应。最后，在保持期 3-9 个月时，23 名受试者的所有磨牙和前磨牙对牙髓测试均呈阳性反应，92 颗牙齿对 EPT 呈阳性反应，25 颗牙齿对 CT 呈阳性反应。在 3-6 周检查时对测试无反应的上颌左侧第一磨牙在最终检查时对 CT 呈阳性反应。
在儿童和青少年接受 RPE 治疗后，本研究检查的后牙永久性牙髓仍然存活。
