Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey.
Center for Dental and Oral Medicine, University of Zürich, Zürich, Switzerland.
J Prosthodont. 2021 Mar;30(3):257-263. doi: 10.1111/jopr.13326. Epub 2021 Feb 24.
An in vitro study to compare the adaptation of denture bases fabricated with 4 different techniques using volumetric 3-dimentional (3D) analysis.
Edentulous maxillary and mandibular casts were scanned, and standardized denture bases were designed using CAD design software. The same standard tessellation language (STL) data were used to produce the denture bases with 4 different fabrication methods: compression molding (CM), injection molding (IM), PMMA milling (PM), and 3D printing (3D) (n = 11/group). Milled wax denture bases were used to fabricate CM and IM groups. Denture bases placed on edentulous casts were scanned using micro-computed tomography (micro-CT). Volumetric gap between denture base and cast was calculated from 6 locations for maxilla (anterior ridge crest, posterior ridge crest, labial vestibule, buccal vestibule, palate, and posterior palatal seal) and 3 locations for mandible (intermolar, molar, and retromolar) in addition to overall gap measurements for edentulous arches. The data were analyzed with factorial analysis of variance (ANOVA), 1-way ANOVA, and post-hoc Duncan tests. Reproducibility of fabrication methods with regard to each location was assessed using Z test (α = 0.05).
In the maxilla, the highest and lowest palatal gap measurements were recorded for CM (898.44 ± 87.73 mm ) and PM (357.16 ± 57.68 mm ) (p = 0.05). The highest gap measurements for CM and 3D were at palate and, for IM and PM were at posterior ridge crest. In mandible, the volumetric gap measurements for CM were the highest and for PM were the lowest irrespective of location (p = 0.05). PM group showed the best reproducibility and adaptation with the lowest overall mean gaps for both edentulous arches (p = 0.05).
Denture bases milled from PMMA blocks showed better adaptation than 3D printed, or wax milled and conventionally fabricated denture bases for both maxillary and mandibular arches. PMMA milling is a reproducible technique that enables the construction of accurate dentures. Clinicians should be cautious about the palatal gap when the compression molding technique is used. Micro-CT is a valid technique for evaluating the denture base adaptation.
通过体三维（3D）分析比较 4 种不同技术制作的义齿基托的适应性。
对无牙上颌和下颌模型进行扫描，并使用 CAD 设计软件设计标准化义齿基托。使用相同的标准网格语言（STL）数据通过 4 种不同的制造方法生产义齿基托：压缩成型（CM）、注塑成型（IM）、PMMA 铣削（PM）和 3D 打印（3D）（n = 11/组）。使用注塑成型和压缩成型技术制造义齿基托时，使用铣削蜡基托。将义齿基托放置在无牙模型上，使用微计算机断层扫描（micro-CT）进行扫描。从 6 个部位（上颌牙槽嵴顶、后牙槽嵴顶、唇颊前庭、颊侧前庭、腭和后腭封闭）和 3 个部位（下颌磨牙间、磨牙和磨牙后区）计算义齿基托和模型之间的容积间隙，以及无牙弓的总间隙测量值。使用方差分析（ANOVA）、单因素方差分析和事后邓肯检验对数据进行分析。使用 Z 检验（α = 0.05）评估各部位制造方法的重现性。
在上颌，CM（898.44 ± 87.73mm）和 PM（357.16 ± 57.68mm）的腭部间隙测量值最高和最低（p = 0.05）。CM 和 3D 的最高间隙测量值在腭部，而 IM 和 PM 的最高间隙测量值在后牙槽嵴顶。在下颌，CM 的容积间隙测量值最高，而 PM 的最低，无论位置如何（p = 0.05）。PM 组的整体平均间隙最小，表明其具有最佳的重现性和适应性，适用于上下颌无牙弓（p = 0.05）。
对于上颌和下颌牙槽，从 PMMA 块铣削的义齿基托比 3D 打印、蜡铣削和传统制造的义齿基托具有更好的适应性。PMMA 铣削是一种可重复的技术，可用于制作精确的义齿。当使用压缩成型技术时，临床医生应注意腭部间隙。微 CT 是评估义齿基托适应性的有效技术。
