Statement of problem

The surface hardness and roughness of different glaze materials for denture base acrylic resins have not been well reported.

Purpose

The purpose of the study was to measure the surfaces hardness, elastic modulus and surface roughness of 5 different light-polymerized glaze materials for poly methyl methacrylate (PMMA) denture base materials.

Material and methods

A total of 210 PMMA resin specimens (10 × 5 × 2 mm) were prepared (30 per group); control group was untreated, group 1 was surface treated with conventional pumice and high shine paste; group 2 to 6 specimens were glaze coated with different commercially available denture glaze materials. 20 specimens out of 30 underwent thermocycling to simulate 6 months and 12 months in vivo. Nanoindentation was performed to measure the surface hardness and elastic modulus. Surface roughness was quantitatively analysed using surface metrology software and qualitatively analysed under scanning electron microscope (SEM). Collected data was statistically analysed using SPSS version 24.

Results

The mean surface hardness of tested specimens ranged from 0.33 ±0.09 GPa to 0.68 ±0.10 GPa. Specimens coated with Optiglaze produced statistically higher surface hardness compared to other groups (P< 0.01). Aging of 6 months and 12 months was found to have no statistical significance for all groups’ surface hardness values. For elastic modulus, specimens coated with Nanovarnish produced statistically higher values compared to other groups (P= 0.03). Thermocycling showed no influence on the elastic modulus of specimens. The mean surface roughness of all groups ranged from 0.16 ±0.01 to 0.30 ±0.02 μm with no statistical significance between groups (P= 0.67). However, under SEM analysis, surfaces showed increased roughness over time.

Conclusions

Statistically significant differences in surface hardness and elastic modulus were found among the different types of surface coated denture acrylic resins. Silica-nanoparticle containing surface coatings produced the highest surface hardness and elastic modulus, however there was no statistical significance found in aging for 6 and 12 months. Contrary to expectations, the surface roughness did not have a significant increase in all groups over time, despite changes observed under SEM.

Clinical implications

This study will contribute to our understanding of surface glazed PMMA acrylic resin denture materials and how it improves the surface strength. This research can help dental clinicians and technicians select the most effective polishing and coating material for the dentures.

中文翻译：

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评估含有光聚合义齿釉料的纳米粒子的表面粗糙度，硬度和弹性模量。

问题陈述

义齿基丙烯酸树脂的不同釉料的表面硬度和粗糙度尚未得到很好的报道。

目的

这项研究的目的是测量5种用于聚甲基丙烯酸甲酯（PMMA）义齿基体材料的光聚合釉材料的表面硬度，弹性模量和表面粗糙度。

材料与方法

总共准备了210个PMMA树脂样品（10×5×2 mm）（每组30个）。对照组未经处理，第1组用常规浮石和高光膏进行表面处理。第2至第6组样品用不同的可商购的义齿釉材料涂覆釉。30个样本中有20个进行了热循环，以模拟体内6个月和12个月。进行纳米压痕以测量表面硬度和弹性模量。使用表面计量软件对表面粗糙度进行定量分析，并在扫描电子显微镜（SEM）下进行定性分析。使用SPSS 24版对收集的数据进行统计分析。

结果

被测样品的平均表面硬度范围为0.33±0.09 GPa至0.68±0.10 GPa。与其他组相比，涂有Optiglaze的样品的表面硬度在统计学上更高（P <0.01）。发现6个月和12个月的老化对于所有组的表面硬度值没有统计学意义。对于弹性模量，与其他组相比，涂有纳米清漆的样品产生的统计值更高（P = 0.03）。热循环对样品的弹性模量没有影响。所有组的平均表面粗糙度范围为0.16±0.01至0.30±0.02μm，各组之间无统计学意义（P = 0.67）。但是，在SEM分析下，表面随着时间的推移显示出增加的粗糙度。

结论

在不同类型的表面覆盖义齿丙烯酸树脂之间，发现表面硬度和弹性模量具有统计学上的显着差异。含硅纳米颗粒的表面涂层具有最高的表面硬度和弹性模量，但是在老化6个月和12个月时没有统计学意义。与预期相反，尽管在SEM下观察到了变化，但所有组的表面粗糙度并未随时间显着增加。

临床意义

这项研究将有助于我们了解表面釉面的PMMA丙烯酸树脂义齿材料及其如何提高表面强度。这项研究可以帮助牙科临床医生和技术人员为假牙选择最有效的抛光和涂层材料。