Changes in the lip closing force of patients with Class III malocclusion before and after orthognathic surgery

Ability to control directional lip-closing force in skeletal class III patients

BACKGROUND

The relationship between the maximum lip-closing force (LCF) and malocclusion has long been studied. Recently, a method to measure the ability to control directional LCF from eight directions (upper, lower, right, left and the four directions in between) during lip pursing was established.

OBJECTIVE

It is considered important to evaluate the ability to control directional LCF. The aim of this study was to investigate the ability of skeletal class III patients to control directional LCF.

METHODS

Fifteen skeletal class III patients (mandibular prognathism group) and 15 people with normal occlusion (normal occlusion group) were recruited. The maximum LCF and the accuracy rate (the ratio of the matched time in which the participant was able to keep the LCF in the target range over a total time of 6 s) were measured.

RESULTS

The maximum LCF was not significantly different between the mandibular prognathism group and the normal occlusion group. The accuracy rate in the mandibular prognathism group was significantly lower in all six directions than that in the individual normal occlusion group.

CONCLUSION

As the accuracy rate in all six directions was significantly lower in the mandibular prognathism group than that in the normal occlusion group, occlusion and craniofacial morphology might influence lip function.

Evaluation of tongue pressure and lip closing force in bimaxillary orthognathic surgery: A retrospective study

The purpose of this study was to quantitatively compare changes in tongue pressure and lip closing force among skeletal Class II and Class III patients, who had undergone orthognathic surgery, and a control group. Maximum tongue pressure and lip closing forces were measured preoperatively and at 6 and 12 months postoperatively. Time-course changes were analyzed and compared among the groups. The control group involved 40 skeletal Class I occlusion volunteers (20 male and 20 female), the Class II group involved 20 female patients, and the skeletal Class III group involved 40 patients, who were subdivided by sex into two groups comprising 20 males and 20 females, respectively. Time-course changes in tongue pressure were not significantly different between and within groups. However, postoperative lip closing forces became gradually higher in the Class III group female and male subjects compared with the control group, although this was not observed in the Class II group. There were significant correlations between tongue pressure and lip closing force before and after surgery (p = 0.001), and these correlations increased over time. Although there was no significant increase in maximum tongue pressure after orthognathic surgery, there was an associated increase in perioral muscle strength. This suggests that an increase in perioral muscle strength may contribute more to the stability of postoperative jaw morphology.

In situ quantitative assessment of food oral processing parameters: A review of feasible techniques and devices

Oral processing is a combination of various actions, the detailed description of which has always been the subject of relevant research. By means of imaging technology and sensory evaluation, more knowledge of oral processing have been accumulated. Presently, the advances in sensory technology have added quantitative parameters to the qualitative description of oral processing, which also enriched the specifics of each action. Previous studies have shown that oral processing includes lip closure, dental occlusion, masticatory muscles activity, tongue movement, and swallowing, whose processing contains rich information such as the movement of organ and the intensity of organ contacts. "Quantification" was taken in this review as the basic feature of in situ detection information, the relevant parameters and feasible methods for the quantitative description of each activity was recorded in detail. In addition, basic problems and feasible optimization schemes of the existing in situ detection device are also proposed in the hope of promoting the development of in situ detection device thus providing available information for the description of oral processing.

Changes in maximum lip-closing force after extraction and nonextraction orthodontic treatments

Objective

The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes.

Methods

In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations.

Results

Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor-mandibular plane angle.

Conclusions

This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

Pressure and resistance of the lips in subjects with and without occlusal change

ABSTRACT Objective: to evaluate the resistance and pressure of the lips in Class I, II and III Angle’s malocclusion subjects, in comparison to reference values and relate them with gender and age. Methods: a quantitative, descriptive and cross-sectional study. Participants included 40 subjects, 20 women and 20 men, average age 26.3 years, separated by occlusal classification. The volunteers answered on the self-reported performance of the stomatognathic functions and were submitted to the evaluation of the mobility and posture of the lips. Pressure and resistance were measured with the Iowa Oral Performance Instrument (IOPI) and the results compared to the reference values described in the instrument´s manual. The data were analyzed descriptively and, for inferential analysis, Pearson's Chi-Square test was used. The significance level was considered 5%. Results: a decrease in pressure and resistance values wasobserved in all patients, including Angle’s class I group. There was an inverse relationship between the age of the subjects and the values of pressure of lips with statistical significance (p = 0.02). In general, women had lower pressure values than men. Conclusion: all study subjects had lower pressure of the lips than the reference values described in the literature.

Tongue pressure distribution of individual normal occlusions and exploration of related factors

Background

Tongue plays an important part in oral and maxillofacial system. Measurement of tongue pressure helps to evaluate the performance of tongue movement.

Objectives

To establish a system for measuring tongue pressure against hard palate and to preliminarily explore pressure distribution of individual normal occlusions and the relationship with dental arch form.

Methods

A total of 19 volunteers of individual normal occlusions out of 189 dental students met inclusion criteria (nine males, ten females, aged 25.53 ± 0.96 years). A force‐sensing resistor device was used to measure tongue pressure at rest and functional state (swallowing). We observed tongue pressure of four channel (anterior, posterior and lateral sides of hard palate) in sitting, supine position and swallowing. We analysed pressure differences according to gender and explored correlation relationship between tongue pressure and dental arch width and length using 3D digital maxillary image.

Results

In rest, tongue pressure against hard palate increased from front to back in both sitting and supine position, without gender differences. When swallowing saliva, the pressure at lateral sides of females was found significantly higher than that of males. Bivariate correlation analysis revealed duration of swallowing was positively correlated with BMI and weight at posterior region and positively correlated with palatal length at anterior palate. The greater the dental arch width, the smaller the pressure of swallowing in the anterior and lateral region.

Conclusion

In rest, there was consistent pressure of tongue against hard palate. The pressure increased significantly during swallowing, especially in females. Tongue pressure was related to dental arch length, width, BMI and weight.

Development and application of a perioral force measurement system for infants with cleft lip and palate

BACKGROUND

Muscles converge or intertweave around the perioral area, and this can be treated with sequential therapy in infants with cleft lip and palate (CLP). The force of perioral muscles has a great influence on maxillary development and morphology. Perioral force in infants with CLP has not been well studied, and accurate and reliable measurement of perioral force in infants remains a challenge. This study aimed to investigate a new way to accurately and reliably measure perioral force in infants with unilateral CLP (UCLP) and explore the change before and after cheiloplasty.

STUDY DESIGN

A perioral force measurement system was developed and applied to measure perioral force at labial frenum area and the commissures on both the normal and the cleft sides of four infants with UCLP before and after cheiloplasty. The results were analyzed using the SPSS 19.0 software.

RESULTS

The perioral force measurement system appears to produce valid results in infants with UCLP. Before cheiloplasty, the perioral force of labial frenum area was 1.79 ± 0.94 g/cm² and that of commissure on the normal and cleft sides was 5.41 ± 1.01 g/cm² and 3.12 ± 1.55 g/cm², respectively (P < 0.05). After cheiloplasty, perioral force of labial frenum area was 12.73 ± 3.51 g/cm² and that of commissure on the normal and cleft sides was 7.64 ± 1.64 g/cm² and 7.27 ± 1.89 g/cm², respectively (P > 0.05).

Change in lip closing force in Classes II and III malocclusion before and after sagittal split ramus osteotomy with Le Fort I osteotomy

PURPOSE

The purpose of this study was to examine lip closing force in Class II and III patients before and after orthognathic surgery.

SUBJECT AND METHODS

The subjects were 45 patients (15 Class II women, 15 Class III men and 15 Class III women) diagnosed with jaw deformity who underwent sagittal split ramus osteotomy with Le Fort I osteotomy and 30 controls with normal skeleton and occlusion (15 men, 15 women). Maximum and minimum lip closing forces were measured using Lip De Cum^® before and after surgery, and compared statistically.

RESULTS

In the Class II women, maximum and minimum lip closing forces did not change after surgery. However, maximum and minimum lip pressure increased significantly in the Class III men (P = 0.0116, P = 0.0295) and maximum lip closing force increased significantly in the Class III women (P = 0.0082). After 6 months, maximum lip closing force was significantly lower in both Classes II and III women than in the control women (P = 0.0002, P = 0.0045).

CONCLUSIONS

This study suggested that maximum postoperative lip pressure did not improve in the Class II women, although maximum lip closing force increased in the Class III men and women after sagittal split ramus osteotomy with Le Fort I osteotomy.

Evaluation of Changes in Lip Closing Force After Surgically Assisted Rapid Maxillary Expansion

OBJECTIVE

Morphological changes in patients subjected to surgical treatment to correct occlusal discrepancies may lead to various functional changes. The aim of the present study was to evaluate changes in lip closing force after surgically assisted rapid maxillary expansion in skeletally mature patients.

METHODS

The study involved 7 female and 7 male patients treated with surgically assisted rapid maxillary expansion. Maximum and minimum lip pressures of patients were measured with Lip De CumLDC-110R. The intercanine distance and incisors angulations were measured preoperatively (T0), at the end of the expansion (T1), at the end of the third month of retention (T2), and at the end of the sixth month of retention (T3).

RESULTS

The greatest values of maximum and the minimum lip closing force were observed at the end of the expansion period significantly. The intercanine distance and inclinations of incisors measured at the third and sixth months showed a significant decrease.

CONCLUSIONS

The present study demonstrated that, following surgically assisted rapid palatal expansion, both the maximum and the minimum lip closing force increases had a tendency to revert to their initial values 6 months after surgery.

Lip closing force of Class III patients with mandibular prognathism: a case control study

INTRODUCTION

To compare the lip closing force of patients with mandibular prognathism to that of patients without dentofacial anomalies.

METHODS

The subject group included 62 female patients of Class III relationship with mandibular prognathism. The control group been comprised of 71 patients of Class I relationships without skeletal deformities. Maximum lip closing force and average lip closing force were measured using a Y-meter. Student's t-test was carried out to analyse the differences between the groups. Correlation and stepwise multiple linear regression analyses were performed to analyse the relationship between lip closing force and craniofacial morphology.

RESULTS

The lower lip closing force of subjects with mandibular prognathism was significantly greater than that of patients in the control group (P < 0.001), while the upper lip closing force showed no difference (P > 0.05). The lower lip closing force of patients with mandibular prognathism was strongly correlated with IMPA (Lower Incisor - Mandibular Plane angle, P < 0.001) and FMA (Frankfort Plane-Mandibular Plane angle, P < 0.001). Multiple regression equations: (MaxLL) = 12.192 - 0.125 * (IMPA) + 0.082 (FMA); (AveLL) = 9.112 - 0.091 * (IMPA) + 0.054 (FMA).

CONCLUSIONS

The lower lip closing force was markedly increased in Class III patients with mandibular prognathism and was strongly correlated with lower incisor position and mandibular plane angle.