Jemt Torsten, Ahlberg Gunilla, Henriksson Kristina, Bondevik Olav
Department of Prosthetic Dentistry/Dental Material Science, Institute of Odontology, Sahlgrenska Academy at Göteborg University, Göteborg, Sweden.
Int J Prosthodont. 2006 Sep-Oct;19(5):455-61.
To measure the long-term changes of clinical crown height in patients treated with single-implant crowns and compare them to those of an adult population with normal dentition.
The test group comprised 23 patients, consecutively restored with a total of 48 single-implant crowns in the anterior maxilla. Mean age was 26.1+/-11.4 years at inclusion. Original master casts were stored after treatment, and patients were recalled for new study casts an average of 15.8+/-0.74 years later. The control group comprised 141 dental students with a mean age of 22.9 +/-1.20 years at inclusion. Study casts were made at inclusion and after 10 (n = 141) and 20 years (n = 60). Clinical crown height was measured for maxillary anterior teeth, and data were pooled and compared regarding clinical crown height and changes in height.
Implant clinical crowns were an average of 0.6+/-1.04 mm longer than the contralateral teeth (P < .05). Central and lateral incisors showed mucosal recession at an average of 0.4+/-0.53 mm (P < .05) and 0.6+/-0.58 mm (P < .01), respectively. In the control group, only minor insignificant changes (+/-0.1 mm) in mean clinical crown height could be observed during the follow-up period. However, obvious individual variations of changes could be found in the control group, and were more pronounced for women. Altogether, 15% and 9% of measured teeth showed > or = 1.0 mm increase or decrease of clinical crown height during 20 years, respectively. Initially, shorter teeth presented a trend (P < .05 to .001) of more mucosal recession than longer teeth.
Mean values of clinical crown height disguise significant individual variations of changes. To perform a risk evaluation for potential future mucosal recession, it could be suggested that greater changes in clinical crown height may occur in patients provided with implant-supported crowns than in untreated control subjects, possibly more for women than men, and more for initially shorter teeth than for longer adjacent teeth.
测量单颗种植冠修复患者临床冠高度的长期变化，并与牙列正常的成年人群进行比较。
试验组包括23例患者，共48颗上颌前牙单颗种植冠修复。纳入时平均年龄为26.1±11.4岁。治疗后保存原始工作模型，平均15.8±0.74年后召回患者制取新的研究模型。对照组包括141名牙科学生，纳入时平均年龄为22.9±1.20岁。在纳入时、10年（n = 141）和20年（n = 60）时制取研究模型。测量上颌前牙的临床冠高度，并汇总数据，比较临床冠高度及其变化。
种植体支持的临床冠比同侧牙平均长0.6±1.04 mm（P <.05）。中切牙和侧切牙的黏膜退缩平均分别为0.4±0.53 mm（P <.05）和0.6±0.58 mm（P <.01）。在对照组中，随访期间平均临床冠高度仅观察到微小的无显著变化（±0.1 mm）。然而，对照组中可发现明显的个体变化，女性更为明显。在20年期间，总共15%和9%的测量牙齿临床冠高度分别增加或减少≥1.0 mm。最初，较短的牙齿比长牙齿有更明显的黏膜退缩趋势（P <.05至.001）。
临床冠高度的平均值掩盖了显著的个体变化。为了对未来潜在的黏膜退缩进行风险评估，可能提示种植体支持冠修复患者的临床冠高度变化可能比未治疗的对照受试者更大，女性可能比男性更明显，最初较短的牙齿比相邻的长牙齿更明显。
