Investigation on the quality analysis of 1 312 single crown digital models

Hua Xi Kou Qiang Yi Xue Za Zhi. 2022 Jan 25;40(1):52-60. doi: 10.7518/hxkq.2022.01.008.
[Article in English, Chinese]

Abstract

Objectives: This study aimed to investigate the quality of single crown digital models, enhance communication between clinicians and technicians, and improve the quality of restorations to further reduce remake rate.

Methods: A total of 1 312 single crown digital models (180 anterior teeth, 294 premolars, and 838 molars) were randomly selected from a large commercial dental factory. The digital models were evaluated by three investigators with the same working experience with the same intraoral scanning system (CEREC). CEREC SW 4.4 was used in capturing the images of single crown preparations, and prepCheck 3.1 was used in evaluating the quality of single crown digital models.

Results: Approximately 6.55%, 0.08%, 81.17%, 19.59%, and 22.48% of 1 312 single crown digital models did not meet the standards of the undercut, surface quality, margin quality, buccal-lingual taper, and mesiodistal taper, respectively. Moreover, 23.25%, 28.51%, 28.43%, and 28.35% of the investigated single crown digital models did not meet the standards of the buccal inclination taper, lingual inclination taper, mesial inclination taper, and distal inclination taper, respectively. The quality of anterior teeth, premolars, molars at the margin quality, buccal-lingual taper, mesiodistal taper, buccal inclination taper, lingual inclination taper, mesial inclination taper, and distal inclination taper significantly varied in the evaluation results (P<0.01).

Conclusions: In addition to the undercut and surface quality met the standard, the overall situation of the quality of the single crown digital preparation model was poor, and the quality of the preparation needs to be improved urgently.

目的: 探讨单冠预备体数字化模型的质量现状,为医技间科学交流、提高修复体质量、降低返工率提供基础数据。方法: 随机抽取某一大型义齿工厂的1 312件单冠数字化模型(前牙180件,前磨牙294件,磨牙838件),数字化模型由3名工龄一致的调查员使用同一椅旁口内扫描系统(CEREC)扫描获得的。采用CEREC SW 4.4软件对单冠初始模型的数字化图像处理重建;进一步采用牙体预备评估软件prepCheck 3.1对上述单冠数字模型进行质量数据收集、提取及汇总分析。结果: 1 312件单冠数字化模型倒凹评价不达标率为6.55%,表面光滑度不达标率为0.08%,肩台质量不达标率为81.17%,颊舌向聚合度的不达标率为19.59%,近远中向聚合度的不达标率为22.48%。颊侧分离角的不达标率为23.25%,舌侧分离角的不达标率为28.51%,近中分离角的不达标率为28.43%,远中分离角的不达标率为28.35%。统计分析显示:前牙、前磨牙、磨牙在肩台质量、颊舌向聚合度、近远中向聚合度、颊侧分离角、舌侧分离角、近中分离角、远中分离角的质量分级结果上的差异具有统计学意义(P<0.01)。结论: 除倒凹和表面光滑度指标达标外,单冠数字化预备体模型的整体质量情况不佳,预备体质量亟待提升。数字化牙体预备评估系统评估结果客观真实,具有极大的发展前景。.

Keywords: digital model; initial plaster model; intraoral scanning system; model scanning system; single crown preparation; tooth preparation evaluation software.

Grants and funding

[基金项目] 四川省药监局科研项目(2018-QT-011)