Thickness Of Lip Research Articles

Soft tissue profile changes after Le Fort I osteotomy in UCLP patients

The changes in soft tissue profile after Le Fort I osteotomy were evaluated cephalometrically in 38 consecutive UCLP patients (25 males, 13 females) operated on between 1987 and 1995. Mean age at operation was 23.5 years. The one-piece Le Fort I osteotomy was fixed with titanium plates and the osteotomy site was bone grafted. Neither intermaxillary fixation nor occlusal splints were used postoperatively. Soft tissue changes were analyzed both horizontally and vertically by cephalograms taken shortly before surgery, 6 months and 1 year postoperatively. The mean maxillary skeletal advancement (point A) during surgery was 3.8 mm and mean vertical lengthening 4.4 mm. One year postoperatively the horizontal change in the upper lip profile (point a) was 80% of the skeletal change. Vertically, the soft tissue change in the upper lip was smaller 40%, but increased significantly (to 58%) if V-Y plasty was used. The V-Y plasty also increased the anteroposterior thickness of the upper lip. No significant soft tissue changes were observed between 6 months and 1 year postoperatively.

Comparison of sedative effects of romifidine following intravenous, intramuscular, and sublingual administration to horses

Abstract Objective To compare sedative effects of romifidine following IV, IM, or sublingual (SL) administration in horses. Animals 30 horses that required sedation for routine tooth rasping. Procedure Horses (n = 10/group) were given romifidine (120 μg/kg) IV, IM, or SL. Heart rate, respiratory rate, head height, distance between the ear tips, thickness of the upper lip, response to auditory stimulation, response to tactile stimulation, and degree of ataxia were recorded every 15 minutes for 180 minutes. Tooth rasping was performed 60 minutes after administration of romifidine, and overall adequacy of sedation was assessed. Results IV and IM administration of romifidine induced significant sedation, but SL administration did not induce significant sedative effects. Scores for overall adequacy of sedation after IV and IM sedation were not significantly different from each other but were significantly different from scores for horses given romifidine SL. Sedative and other effects varied among groups during the first 60 minutes after drug administration; thereafter, effects of IV and IM administration were similar. Conclusions and Clinical Relevance Onset of action was fastest and degree of sedation was greater after IV, compared with IM, administration of romifidine, but duration of action was longer after IM administration. Sublingual administration did not result in clinically important sedative effects. (Am J Vet Res 1999;60:954-959)

Growth changes in the cranial base and the face: a longitudinal cephalometric study of linear and angular changes in adult Norwegians.

The purpose of this study was to examine the natural growth changes which occur between 22 and 33 years of age. The material consisted of two series of cephalograms of 74 females and 90 males with approximately 11 years between the two series. None of the subjects had orthodontic retainers when the first exposure was undertaken, or orthodontic treatment, or surgery during the observation period. The measurements were carried out by using a modified Dentofacial Planner program SHORT, and both linear and angular measurements were made. The overall changes were an increase in anterior facial height which mostly occurred in the lower face, and an increase in the length of the mandible. These changes were statistically significant in both genders. The females also had a significant posterior rotation of the mandible. There was a significant decrease in the thickness of the upper lip both in females and males, and the males had a significant increase in thickness of the soft tissue on the mandibular profile. Although there were some statistical changes in the observation period, none of the linear changes exceeded 1.35 mm. The largest angular change was a 1.44 degrees retroclination of the upper incisors in females. The differences between the genders were statistically significant only in three angular and two soft tissue measurements.

The contact forces of lip seals for a ball bearing

Simplified equations are derived for the evaluation of the axial contact forces for a special design of lip seal for bearings. The contact forces of the lip seals for a ball bearing are analysed as a function of the ratio of real contact length, the thickness of the seal lip, the inclined angle of the seal lip, and the deflected interference between the edge of the seal lip and the rotating inner ring. An experimental apparatus is developed for testing the seal lip contact forces. Using a non-linear FEM program, the contact force of the seal lip was analysed for various values of the deflected interference. The calculated results show that the deflected interference and the circumferential stress cause considerable change of contact forces for the low sealed lubricant pressure. The results of contact forces obtained from the derived equation for the contact force are in good agreement with experimental and numerical results.

Soft-tissue and dentoskeletal profile changes associated with mandibular setback osteotomy

The aims of the present retrospective cephalometry study were (1) to describe the interrelationships of the soft-tissue and dentoskeletal profiles after total mandibular setback osteotomies and (2) to detect whether there were any cephalometric variables that could contribute to an accurate prediction of the surgical effect on the soft-tissue profile. The presurgical and postsurgical lateral cephalograms of 50 consecutively treated patients (37 females and 13 males) were used; these patients had received combined orthodontic-surgical management of mandibular prognathism by means of a bilateral vertical ramus osteotomy with an extraoral approach. At the time of surgery, their ages ranged from 17 to 41 years. Lateral cephalograms with the teeth in habitual occlusion taken before and approximately 1 year after surgery were available for all patients. A computerized cephalometric appraisal, named profile analysis, was developed and used, including variables corresponding to sagittal and vertical relationships of skeletal and soft-tissue profiles, incisal relationships, soft-tissue thickness, and lip morphology. The statistical elaboration of the data was made by means of paired t test, Pearson's product-moment coefficient correlation, and multiple regression analyses. The assessment of the results disclosed that considerable facial changes and improvement took place after the surgical procedure. The skeletal and soft-tissue facial profiles were straightened and the posture of the lips was improved. The normal incisal relationship achieved became influential on the soft tissues overlying both incisors and led to a better lip competence and posture. Posterior movement at points B and Po was accompanied by reductions ranging from 91% to 103% of the corresponding soft tissues. The presence of both significant correlation coefficients (p less than 0.05) and high r square values (greater than 0.70) in the multiple regression analysis for the osseous tissue variables N-B and N-Po, alone or together with the overjet and S-N-B angle, respectively, reflected their high prediction value with regard to the sagittal relationship of the lower lip, its thickness, and the soft-tissue thickness at the chin area. The findings of Pearson's product-moment coefficient correlation also indicated that the operative changes of the thickness of the upper lip, the lower lip, and the soft tissue at the chin region are influenced by the initial preoperative thickness of the area.

Relationship between lip strength and lip function in posture and chewing.

The relationship between lip strength, measured clinically with a dynamometer, and the electromyographically recorded activity of the lips at rest and during chewing was studied in 50 children, aged 7 to 13 years, with varying types of malocclusion. The electromyographic activity of the lips was also related to bite and facial morphology recorded on dental casts and profile radiographs. There was no correlation between lip strength and the EMG activity of the lips at rest or during chewing. The postural lip activity was not correlated to dentoalveolar cephalometric variables, including incisor relationship and inclination, but was correlated to lower arch width and the thickness of the upper lip. The activity of the lips during chewing was correlated to dental arch size, to incisor relationship and to lip morphology and relationship. This was interpreted as an adaptation of the chewing activity to bite morphology. There was no evidence that lip function influenced bite morphology.

Soft-tissue profile changes in Class II treatment

By means of an x-ray cephalometric method, the soft-tissue and skeletal profiles were evaluated in postnormal Class II, Division 1 cases before and after orthodontic treatment. A comparison of the Class II cases before and after treatment showed that the main change that resulted from treatment involved the position of the upper incisors, which were more posteriorly located; also, the subspinale, lower incisors, the upper lip, and, to a lesser degree, the lower lip were more posteriorly located after treatment. A comparison of the thickness of the soft tissues after treatment with that before treatment in the postnormal cases showed that the thickness of the upper lip had increased and that of the lower lip had decreased after treatment. The degree of correlation between changes in the soft-tissue profile and changes in the skeletal profile during orthodontic treatment varied. Among the skeletal structures that were most affected during treatment, there was fairly good correlation between the displacement of the subspinale, incision inferior, and supramentale and the immediately overlying soft-tissue points (sulcus superior, labrale inferior, and sulcus inferior, respectively). By contrast, the correlation between the displacement of the incision superior and the labrale superior was rather poor. On the average, the retraction of the subspinale, incision inferior, and supramentale was accompanied by a practically equally large retraction of the respective soft-tissue points, whereas the ratio between the retraction of the incision superior and the labrale superior is about 2.5:1. There were large individual variations in the response of the soft tissues to changes in the underlying skeletal structures.