Evaluation of lip closing force in adult female with normal occlusion based on the self-developed LCF measurement system

doi:10.11958/20260727

Abstract

Abstract:

Objective To assess the characteristics of lip closing force (LCF) in young adult females with normal occlusion using a self-developed LCF measurement system, and to clarify the relationship between lip soft tissue indicators and lip closure stability, so as to provide a basis for clinical evaluation of lip muscle function. Methods A total of 81 adult female volunteers aged 19 to 24 years with normal occlusion were enrolled in this study. Eight cephalometric lip soft tissue indicators (A-Sn, UIC-UL, B-Si, LIC-LL, Sn-Stms, Stmi-Si, UL-EP and LL-EP) were measured. Meanwhile, LCF electrical signals were collected via the self-developed LCF measurement system, LCF curves were plotted, and three core indicators including maximum value, mean value and first wavelet packet entropy (FWPE) were extracted. The lip soft tissue indicators were divided into 5 grades according to the degree of deviation from the median (grade 5: closest to the standard; grade 1: most deviant), and then integrated into a clinical grade (CG). After eliminating invalid data caused by environmental interference and subjective consciousness, the effects of LCF-related indicators (maximum value, mean value, and stability) on lip soft tissue morphology were analyzed. The dependent variable CG grade was an ordinal categorical variable. Eventually, an ordinal Logistic regression model was constructed with 38 valid samples. Pseudo R² and P-value (test level α=0.05) were adopted to evaluate the reliability of the regression model. Results The finally established regression model showed acceptable fitting effect (Pseudo R²=0.532). An increase in FWPE would increase the probability of CG tending to a lower grade (β₃=-0.175, OR=0.839, 95%CI: 0.722-0.976), indicating that the lip soft tissue indicators deviated more from the standard values. In contrast, the smaller the FWPE, the better the lip closure stability, and the closer the lip soft tissue indicators were to the standard values. Conclusion The self-developed LCF measurement system can be effectively used for the evaluation of lip closing force in adult females with normal occlusion.

Key words: dental occlusion, wavelet analysis, entropy, femininity, adult, lip closing force, stability

CLC Number:

R782.2

Figures/Tables 10

References 27

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信号类型	判断标准
有效信号	（1）信号强度≥峰值的10%，连续无中断持续≥16 s；（2）波形平滑，无明显干扰，基线漂移≤±0.5 mV，功率谱密度（PSD）拟合的决定系数R²≥0.8；（3）信号峰值清晰，上升至峰值时间≤1 s，有效时段内无数据丢失。
无效信号	（1）稳定时长<16 s，或信号在达到峰值后10 s内降至峰值的<5%；（2）波形畸变、出现尖峰噪声（基线漂移>±0.5 mV），或PSD拟合决定系数R²<0.8；（3）无清晰峰值、波动异常、有效时段内存在数据丢失或信号中断。

信号类型	判断标准
有效信号	（1）信号强度≥峰值的10%，连续无中断持续≥16 s；（2）波形平滑，无明显干扰，基线漂移≤±0.5 mV，功率谱密度（PSD）拟合的决定系数R²≥0.8；（3）信号峰值清晰，上升至峰值时间≤1 s，有效时段内无数据丢失。
无效信号	（1）稳定时长<16 s，或信号在达到峰值后10 s内降至峰值的<5%；（2）波形畸变、出现尖峰噪声（基线漂移>±0.5 mV），或PSD拟合决定系数R²<0.8；（3）无清晰峰值、波动异常、有效时段内存在数据丢失或信号中断。

CG等级	波动幅度	A-Sn	UIC-UL	B-Si	LIC-LL	Sn-Stms	Stmi-Si	UL-EP	LL-EP
5	±20%	22.82~23.84	22.32~23.28	20.79~21.89	-0.18~0.78	37.39~38.75	28.88~30.34	-1.13~-0.29	-0.18~0.78
4	+20%~40%	23.84~24.35	23.28~23.77	21.89~22.44	0.78~1.26	38.75~39.43	30.34~31.07	-0.29~0.14	0.78~1.26
4	-20%~-40%	22.31~22.82	21.83~22.32	20.24~20.79	-0.66~-0.18	36.71~37.39	28.15~28.88	-1.56~-1.13	-0.66~-0.18
3	+40%~60%	24.35~24.86	23.77~24.25	22.44~22.99	1.26~1.74	39.43~40.12	31.07~31.79	0.14~0.56	1.26~1.74
3	-40%~-60%	21.80~22.31	21.35~21.83	19.70~20.24	-1.14~-0.66	36.02~36.71	27.43~28.15	-1.98~-1.56	-1.14~-0.66
2	+60%~80%	24.86~25.37	24.25~24.74	22.98~23.53	1.74~2.22	40.12~40.80	31.79~32.52	0.56~0.99	1.74~2.22
2	-60%~-80%	21.29~21.80	20.86~21.35	19.15~19.70	-1.62~-1.14	35.34~36.02	26.70~27.43	-2.41~-1.98	-1.62~-1.14
1	+80%~100%	25.37~25.88	24.74~25.22	23.53~24.08	2.22~2.70	40.80~41.48	32.52~33.25	0.99~1.41	2.22~2.70
1	-80%~-100%	20.78~21.29	20.38~20.87	18.60~19.15	-2.10~1.62	34.66~35.34	25.97~26.70	-2.83~-2.41	-2.10~-1.62

CG等级	波动幅度	A-Sn	UIC-UL	B-Si	LIC-LL	Sn-Stms	Stmi-Si	UL-EP	LL-EP
5	±20%	22.82~23.84	22.32~23.28	20.79~21.89	-0.18~0.78	37.39~38.75	28.88~30.34	-1.13~-0.29	-0.18~0.78
4	+20%~40%	23.84~24.35	23.28~23.77	21.89~22.44	0.78~1.26	38.75~39.43	30.34~31.07	-0.29~0.14	0.78~1.26
4	-20%~-40%	22.31~22.82	21.83~22.32	20.24~20.79	-0.66~-0.18	36.71~37.39	28.15~28.88	-1.56~-1.13	-0.66~-0.18
3	+40%~60%	24.35~24.86	23.77~24.25	22.44~22.99	1.26~1.74	39.43~40.12	31.07~31.79	0.14~0.56	1.26~1.74
3	-40%~-60%	21.80~22.31	21.35~21.83	19.70~20.24	-1.14~-0.66	36.02~36.71	27.43~28.15	-1.98~-1.56	-1.14~-0.66
2	+60%~80%	24.86~25.37	24.25~24.74	22.98~23.53	1.74~2.22	40.12~40.80	31.79~32.52	0.56~0.99	1.74~2.22
2	-60%~-80%	21.29~21.80	20.86~21.35	19.15~19.70	-1.62~-1.14	35.34~36.02	26.70~27.43	-2.41~-1.98	-1.62~-1.14
1	+80%~100%	25.37~25.88	24.74~25.22	23.53~24.08	2.22~2.70	40.80~41.48	32.52~33.25	0.99~1.41	2.22~2.70
1	-80%~-100%	20.78~21.29	20.38~20.87	18.60~19.15	-2.10~1.62	34.66~35.34	25.97~26.70	-2.83~-2.41	-2.10~-1.62

组别	n		年龄/岁	BMI/（kg/m²）			A-Sn/mm			UIC-UL/mm
有效组	38		20.1±1.2	20.3±1.1			23.1（22.0，24.2）			22.9（21.8，24.2）
剔除组	43		20.0±1.3	19.9±1.5			22.7（21.9，24.0）			23.0（21.9，24.3）
t或Z			0.125	1.380			0.680			0.720
组别		B-Si/mm				LIC-LL/mm		Sn-Stms/mm
有效组		21.3（20.0，22.9）				0.7（-0.3，1.8）		37.9（36.3，39.8）
剔除组		21.7（20.0，23.5）				0.6（-0.4，1.7）		37.5（35.8，39.9）
t或Z		0.560				0.120		0.500
组别		Stmi-Si/mm			UL-EP/mm				LL-EP/mm
有效组		29.2（27.5，31.7）			-0.1（-1.3，0.8）				0.2（-0.8，0.8）
剔除组		29.0（27.5，31.3）			-0.1（-1.5，0.8）				-0.1（-0.9，0.8）
t或Z		0.420			0.000				0.110