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

doi:10.7518/hxkq.2022.01.008

Abstract

Abstract: Objective

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).

Conclusion

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.

Key words: single crown preparation, digital model, initial plaster model, intraoral scanning system, model scanning system, tooth preparation evaluation software

CLC Number:

R 783.2

Lu Jiayi, Zhao Junyi, Gao Jing, Yu Haiyang.. Investigation on the quality analysis of 1 312 single crown digital models[J]. West China Journal of Stomatology, 2022, 40(1): 52-60.

Figures/Tables 6

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Fig 3

Tab 1

Tab 2

Tab 3

References 20

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评估指标	描述值	前牙（n=180）	前磨牙（n=294）	磨牙（n=838）	合计
倒凹	平均值±标准差	0.022±0.053	0.033±0.053	0.026±0.054	0.027±0.054
	95%可信区间	0.014~0.029	0.027~0.039	0.022~0.030	0.024~0.030
表面光滑度	平均值±标准差	0.017±0.016	0.022±0.027	0.018±0.015	0.019±0.018
	95%可信区间	0.015~0.02	0.019~0.025	0.017~0.019	0.018~0.020
肩台质量	平均值±标准差	0.238±0.116	0.232±0.115	0.199±0.109	0.212±0.113
	95%可信区间	0.221~0.255	0.219~0.246	0.191~0.206	0.205~0.218
颊舌向聚合度/°	平均值±标准差	33.471±14.250	19.714±10.946	26.361±12.596	25.847±13.129
	95%可信区间	31.389~35.552	18.463~20.966	25.508~27.213	25.136~26.557
近远中向聚合度/°	平均值±标准差	28.741±14.371	21.850±12.263	30.581±13.856	28.372±14.038
	95%可信区间	26.641~30.84	20.448~23.252	29.643~31.519	27.613~29.132
舌侧分离角/°	平均值±标准差	19.045±11.681	10.196±7.299	13.834±9.104	13.733±9.494
	95%可信区间	17.339~20.751	9.361~11.03	13.217~14.450	13.22~14.247
颊侧分离角/°	平均值±标准差	14.583±9.256	9.517±6.880	12.541±8.743	12.143±8.576
	95%可信区间	13.231~15.935	8.731~10.304	11.949~13.133	11.679~12.607
近中分离角/°	平均值±标准差	14.280±10.120	10.928±7.520	14.951±9.250	13.957±9.162
	95%可信区间	12.802~15.758	10.068~11.787	14.325~15.577	13.462~14.453
远中分离角/°	平均值±标准差	14.468±9.229	10.927±7.743	15.643±8.964	14.425±8.945
	95%可信区间	13.120~15.817	10.042~11.812	15.036~16.250	13.941~14.909

评估指标	牙位（中位数）			Kruskal-Wallis检验统计量H值	P值
评估指标	前牙（n=180）	前磨牙（n=294）	磨牙（n=838）	Kruskal-Wallis检验统计量H值	P值
倒凹	0	0.01	0	12.118	0.002**
表面光滑度	0.01	0.02	0.01	5.807	0.060
肩台质量	0.23	0.23	0.19	28.667	0.000**
颊舌向聚合度	33.15	18.85	25.8	124.605	0.000**
近远中向聚合度	25.95	21.2	29.1	93.247	0.000**
舌侧分离角	17.65	8.85	12.9	87.559	0.000**
颊侧分离角	12.80	8.70	11.55	52.295	0.000**
近中分离角	12.25	10.15	13.80	48.367	0.000**
远中分离角	12.20	10.50	14.35	68.560	0.000**

评估指标	分类	前牙/%	前磨牙/%	磨牙/%	总计/%	列联系数	χ2值	P值
倒凹	≤0.05	89.44	81.97	85.32	85.14	0.062	5.062	0.281
	>0.05且≤0.10	5.56	10.20	8.23	8.31
	>0.10	5.00	7.82	6.44	6.55
表面光滑度	≤0.05	96.67	96.26	98.45	97.71	0.079	8.153	0.086
	>0.05且≤0.10	3.33	3.40	1.55	2.21
	>0.10	0.00	0.34	0.00	0.08
肩台质量	≤0.05	2.78	2.38	7.40	5.64	0.117	18.141	0.001**
	>0.05且≤0.10	9.44	12.24	14.32	13.19
	>0.10	87.78	85.37	78.28	81.17
颊舌向聚合度	≥5°且≤20°	12.78	44.90	28.40	29.95	0.268	101.735	0.000***
	<5°或>40°	41.67	12.24	17.42	19.59
	>20°且≤40°	45.56	42.86	54.18	50.46
近远中向聚合度	≥5°且≤20°	25.56	38.10	19.57	24.54	0.193	50.834	0.000***
	<5°或>40°	29.44	13.61	24.11	22.48
	>20°且≤40°	45.00	48.30	56.32	52.97
舌侧分离角	≥2.5°且≤10°	16.11	41.84	30.07	30.79	0.217	64.946	0.000***
	<2.5°或>20°	50.00	21.77	26.25	28.51
	>10°且≤20°	33.89	36.39	43.68	40.70
颊侧分离角	≥2.5°且≤10°	29.44	48.30	34.49	36.89	0.145	28.349	0.000***
	<2.5°或>20°	32.22	18.37	23.03	23.25
	>10°且≤20°	38.33	33.33	42.48	39.86
近中分离角	≥2.5°且≤10°	28.89	40.14	26.01	29.57	0.136	24.724	0.000***
	<2.5°或>20°	32.78	20.75	30.19	28.43
	>10°且≤20°	38.33	39.12	43.79	42.00
远中分离角	≥2.5°且≤10°	31.67	38.10	25.30	29.04	0.138	25.659	0.000***
	<2.5°或>20°	32.78	19.73	30.43	28.35
	>10°且≤20°	35.56	42.18	44.27	42.61

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