Department of Prosthodontics, Preclinical Education and Dental Materials Science, Welschnonnenstr.17, 53111 Bonn, Germany.
Clin Oral Investig. 2012 Apr;16(2):407-11. doi: 10.1007/s00784-011-0530-2. Epub 2011 Mar 1.
This study deals with the development of the retentive forces of double crowns intraorally measured. Twenty-five combined fixed-removable prostheses with a total of 84 double crowns were included in the study. The intraoral measurement was performed at 72 defined measuring points directly adjacent to the double crowns of the dentures. The measurement was performed 4-6 weeks (baseline), 6 months (recall 1), and 18 months (recall 2) after the insertion of the restoration. A specifically designed measuring device was used. The median values for the single measuring points reached 4.705 N at the baseline, 5.190 N after 6 months, and 3.740 N after 18 months. The measured values were analyzed according to differences between the median retention forces at the three defined points in time. The statistical analysis of the median values showed no statistical difference for the retention force change after 6 months but for the decrease until the second recall (Mann-Whitney test). The retention force per denture was calculated by a summation of the single measuring points. At the baseline, 12.9 N was reached. The forces did only decrease slightly and were not statistically significant. The results indicate that retention force values of double crowns, measured intraorally at the patient, do not relevantly change clinically within the first 1.5 years. Within the limitations of this study, it can be stated that wear does not influence the retentive forces of double crowns within the first 18 months. After this period the retention force should be still sufficient for denture retention.
本研究旨在探讨口腔内测量的双冠固位力的发展。共纳入 25 例联合固定-可摘义齿，总计 84 个双冠。在口腔内，在义齿的双冠直接相邻的 72 个定义测量点进行测量。测量分别在修复体插入后的 4-6 周（基线）、6 个月（第 1 次随访）和 18 个月（第 2 次随访）进行。使用专门设计的测量设备。单个测量点的中位数值在基线时为 4.705N，6 个月后为 5.190N，18 个月后为 3.740N。根据三个时间点的中位数固位力差异对测量值进行分析。中位数值的统计分析显示，6 个月后的固位力变化无统计学差异，但直到第二次随访时的下降有统计学差异（Mann-Whitney 检验）。通过对单个测量点的求和计算每个义齿的固位力。基线时达到 12.9N。这些力仅略有下降，且无统计学意义。结果表明，在最初的 1.5 年内，患者口腔内测量的双冠固位力值在临床上没有明显变化。在本研究的限制范围内，可以得出结论，在最初的 18 个月内，磨损不会影响双冠的固位力。在此期间之后，固位力仍应足以保持义齿的固位。
