Steinmassl Otto, Dumfahrt Herbert, Grunert Ingrid, Steinmassl Patricia-Anca
University Hospital for Cranio-Maxillofacial and Oral Surgery, Medical University of Innsbruck, MZA, Anichstr. 35, A-6020, Innsbruck, Austria.
University Hospital for Dental Prosthetics and Restorative Dentistry, Medical University of Innsbruck, MZA, Anichstr. 35, A-6020, Innsbruck, Austria.
Clin Oral Investig. 2018 Nov;22(8):2829-2835. doi: 10.1007/s00784-018-2369-2. Epub 2018 Feb 22.
Resin polymerisation shrinkage reduces the congruence of the denture base with denture-bearing tissues and thereby decreases the retention of conventionally fabricated dentures. CAD/CAM denture manufacturing is a subtractive process, and polymerisation shrinkage is not an issue anymore. Therefore, CAD/CAM dentures are assumed to show a higher denture base congruence than conventionally fabricated dentures. It has been the aim of this study to test this hypothesis.
CAD/CAM dentures provided by four different manufacturers (AvaDent, Merz Dental, Whole You, Wieland/Ivoclar) were generated from ten different master casts. Ten conventional dentures (pack and press, long-term heat polymerisation) made from the same master casts served as control group. The master casts and all denture bases were scanned and matched digitally. The absolute incongruences were measured using a 2-mm mesh.
Conventionally fabricated dentures showed a mean deviation of 0.105 mm, SD = 0.019 from the master cast. All CAD/CAM dentures showed lower mean incongruences. From all CAD/CAM dentures, AvaDent Digital Dentures showed the highest congruence with the master cast surface with a mean deviation of 0.058 mm, SD = 0.005. Wieland Digital Dentures showed a mean deviation of 0.068 mm, SD = 0.005, Whole You Nexteeth prostheses showed a mean deviation of 0.074 mm, SD = 0.011 and Baltic Denture System prostheses showed a mean deviation of 0.086 mm, SD = 0.012.
CAD/CAM produces dentures with better fit than conventional dentures.
The present study explains the clinically observed enhanced retention and lower traumatic ulcer-frequency in CAD/CAM dentures.
树脂聚合收缩会降低义齿基托与承托组织的贴合度，从而降低传统制作义齿的固位力。计算机辅助设计/计算机辅助制造（CAD/CAM）义齿制作是一种减法工艺，聚合收缩不再是问题。因此，人们认为CAD/CAM义齿比传统制作的义齿具有更高的义齿基托贴合度。本研究旨在验证这一假设。
由四个不同制造商（AvaDent、Merz Dental、Whole You、Wieland/Ivoclar）提供的CAD/CAM义齿由十个不同的主模型制作而成。由相同主模型制作的十副传统义齿（包埋加压、长期热聚合）作为对照组。对主模型和所有义齿基托进行扫描并进行数字匹配。使用2毫米网格测量绝对不贴合度。
传统制作的义齿与主模型的平均偏差为0.105毫米，标准差=0.019。所有CAD/CAM义齿的平均不贴合度均较低。在所有CAD/CAM义齿中，AvaDent数字义齿与主模型表面的贴合度最高，平均偏差为0.058毫米，标准差=0.005。Wieland数字义齿的平均偏差为0.068毫米，标准差=0.005，Whole You Nexteeth义齿的平均偏差为0.074毫米，标准差=0.011，Baltic义齿系统义齿的平均偏差为0.086毫米，标准差=0.012。
CAD/CAM制作的义齿比传统义齿更贴合。
本研究解释了临床上观察到的CAD/CAM义齿固位力增强和创伤性溃疡发生率较低的现象。
