Borges Alexandre Luiz Souto, Borges Alessandra Bühler, Uemura Eduardo Shigueyuki, Paes-Júnior Tarcisio José de Arruda, Tango Rubens Nisie, de Araújo José Eduardso Junho, Kimpara Estevão Tomomitsu
Department of Dental Materials and Prosthodontics, School of Dentistry, São José dos Campos, São Paulo State University-UNESP, São José dos Campos, São Paulo, Brazil.
J Contemp Dent Pract. 2010 Jan 1;11(1):E065-72.
The aim of the study was to assess the accuracy of a new intraoral paralleling device for creating proximal guiding planes for removable partial dental prostheses.
Thirty gypsum casts were divided into two groups in which the proximal surfaces of selected teeth were prepared using either a surveying device (Group 1) or the new ParalAB paralleling device (Group 2). In each cast guiding planes were prepared on the distal surface of the maxillary left canine (A), on the mesial and distal surfaces of the maxillary left second molar (B and C), and on the distal surface of the maxillary right canine (D). Each prepared surface formed an angle related to the occlusal plane that was measured five times and averaged by one operator using a tridimensional coordinate machine.
The mean guiding plane angles (+/- standard deviation) for the prepared surfaces were A=91.82 degrees (+/-0.48 degrees ), B=90.47 degrees (+/-0.47 degrees ), C=90.21 degrees (+/-0.76 degrees ), and D=90.50 degrees (+/-0.73 degrees ) for the dental surveyor (Group 1) and A=92.18 degrees (+/-0.87 degrees ), B=90.90 degrees (+/-0.85 degrees ), C=90.07 degrees (+/-0.92 degrees ), and D=90.66 degrees (+/-0.76 degrees ) for the ParalAB paralleling device (Group 2). A two-way ANOVA, Tukey's, and Levène's tests (at p<0.05) revealed statistically significant differences among surfaces prepared by both groups and that one surface (A in Group 2) was more parallel to the path of insertion than the other surfaces.
The ParalAB device was able to prepare parallel surfaces and despite significant difference between groups, the ParalAB presented a small deviation from absolute parallelism and can be considered a valid method to transfer guide plans in the fabrication of removable partial dentures.
The preparation of suitable guiding planes on abutment teeth during the fabrication of removable partial dentures is dependent on the ability of the operator and requires considerable chair time. When multiple teeth are involved, achieving parallelism between abutment surfaces can be technically challenging, especially in posterior regions of the mouth. The ParalAB prototype intraoral paralleling device can aid the clinician during the preparation of accurate guiding planes with a minimum degree of occlusal divergence.
本研究旨在评估一种新型口腔内平行装置在为可摘局部义齿制作近中端导平面时的准确性。
30个石膏模型被分为两组，其中一组使用测量仪（第1组），另一组使用新型ParalAB平行装置（第2组）对选定牙齿的近中面进行预备。在每个模型上，分别在上颌左侧尖牙（A）的远中面、上颌左侧第二磨牙的近中面和远中面（B和C）以及上颌右侧尖牙（D）的远中面制备导平面。每个制备好的表面与咬合平面形成一个角度，由一名操作人员使用三维坐标仪测量5次并求平均值。
使用牙测量仪（第1组）时，制备表面的平均导平面角度（±标准差）为：A = 91.82度（±0.48度），B = 90.47度（±0.47度），C = 90.21度（±0.76度），D = 90.50度（±0.73度）；使用ParalAB平行装置（第2组）时，平均导平面角度为：A = 92.18度（±0.87度），B = 90.90度（±0.85度），C = 90.07度（±0.92度），D = 90.66度（±0.76度）。双向方差分析、Tukey检验和Levene检验（p<0.05）显示，两组制备的表面之间存在统计学上的显著差异，且其中一个表面（第2组中的A）比其他表面更平行于就位道。
ParalAB装置能够制备平行表面，尽管两组之间存在显著差异，但ParalAB与绝对平行度的偏差较小，可被视为在可摘局部义齿制作中转移导平面的有效方法。
在可摘局部义齿制作过程中，在基牙上制备合适的导平面取决于操作人员的能力，且需要相当长的椅旁时间。当涉及多颗牙齿时，实现基牙表面之间的平行度在技术上具有挑战性，尤其是在口腔后部区域。ParalAB原型口腔内平行装置可在临床医生制备精确导平面时提供帮助，使咬合差异最小。
