Salloum Alaa'a M
Department of Removable Prosthodontics, Faculty of Dental Medicine, Damascus University, Damascus, Syria.
Saudi Dent J. 2016 Jan;28(1):56-61. doi: 10.1016/j.sdentj.2015.08.003. Epub 2015 Dec 2.
Tooth movement has been shown to occur during and after the processing of complete dentures. An understanding of this phenomenon may permit one to construct functional complete dentures that require less occlusal adjustment in the articulator and in the patient's mouth.
The purpose of this study was to examine the effects of three different investing methods on tooth movement occurring during the processing of simulated maxillary complete dentures.
Forty-five similar maxillary dentures were made using heat-polymerized acrylic resin, and assigned randomly to three experimental groups (n = 15 each) according to investing method: plaster-plaster-plaster (P-P-P), plaster-stone-stone (P-S-S), and plaster-mix (P-M). Specimens in all experimental groups were compression molded with denture base resin. Transverse interincisor (I-I) and intermolar (M-M) distances, and anteroposterior incisor-molar (LI-LM and RI-RM) distances, were measured with digital calipers at the wax denture stage (pre-polymerization) and after denture decasting (post-polymerization). Analysis of variance and Tukey's test were used to compare the results.
M-M, LI-LM, and RI-RM movement was significantly greater in the P-P-P group than in the P-S-S and P-M groups; no significant difference in I-I movement was observed among groups. Transverse movement along M-M and I-I was significantly greater than anteroposterior movement in the P-P-P group; no significant difference among measurements was observed in the other two groups.
The study results indicate that the use of dental stone or a 50:50 mixture of plaster and stone for investing of dentures is an important factor in efforts to control the magnitude of tooth movement.
已证明在全口义齿制作过程中和制作完成后会发生牙齿移动。了解这一现象可能有助于制作出在牙合架和患者口腔中需要较少咬合调整的功能性全口义齿。
本研究的目的是研究三种不同包埋方法对模拟上颌全口义齿制作过程中牙齿移动的影响。
使用热聚合丙烯酸树脂制作45副相似的上颌义齿，并根据包埋方法随机分为三个实验组（每组n = 15）：石膏 - 石膏 - 石膏（P - P - P）、石膏 - 石 - 石（P - S - S）和石膏 - 混合物（P - M）。所有实验组的标本均用义齿基托树脂进行压缩成型。在蜡型义齿阶段（预聚合）和义齿脱模后（后聚合），用数字卡尺测量横向切牙间（I - I）和磨牙间（M - M）距离，以及前后切牙 - 磨牙（LI - LM和RI - RM）距离。采用方差分析和Tukey检验比较结果。
P - P - P组的M - M、LI - LM和RI - RM移动明显大于P - S - S组和P - M组；各组间I - I移动未观察到显著差异。P - P - P组沿M - M和I - I的横向移动明显大于前后向移动；其他两组测量值之间未观察到显著差异。
研究结果表明，使用牙科石膏或石膏与石的50:50混合物进行义齿包埋是控制牙齿移动幅度的一个重要因素。
