Changes in soft tissue profile after orthodontic treatment with and without extractions.

The effects of orthodontic treatment on the facial profile, with or without the extraction of teeth, have greatly concerned orthodontists. A study was made of 80 patients with Angle Class I malocclusion. Forty patients (24 girls, 16 boys) did not undergo extraction of teeth, and 40 patients (23 girls, 17 boys) underwent extraction of maxillary and mandibular first premolars. Data were obtained from the corresponding lateral radiographs of the head taken before and after orthodontic treatment. The purpose of this study was to compare the response of the soft tissue of the facial profile in Class I malocclusions treated with and without the extraction of the 4 first premolars. The main soft tissue differences between the groups at the end of treatment were more retruded upper and lower lips in the extraction patients.     

Changes in soft tissue facial profile of craniofacial microsomia patients: geometric morphometrics

To analyze changes in the soft tissue profile associated with an inverted L osteotomy, preoperative, early postoperative, and late postoperative lateral cephalographs of 13 children with craniofacial microsomia (mean age 9 +/- 2 years) were scanned, and 11 soft tissue landmarks were digitized (digitization errors insignificant; P > 0.05). Cephalometry, Euclidean distance matrix analysis (EDMA), and thin-plate spline (TPS) analysis were carried out on the mean soft tissue landmark configurations. Cephalometry indicated that there were very few statistically significant differences in mean measurements pre- and postoperatively. In contrast, EDMA determined that there were significant differences (P < 0.05) between mean preoperative, early postoperative, and late postoperative soft tissue configurations, particularly in the labiomental region. Transformation grids obtained from TPS analysis indicated clockwise rotation of the soft tissue configurations with anteroinferior elongation in the labiomental region. Geometric morphometrics indicated that the soft tissue lower facial height increased secondary to the associated underlying skeletal change, improving the profile of patients treated with an inverted L osteotomy of the mandible for the correction of craniofacial microsomia.     

Changes in the soft tissue profile after extraction orthodontic therapy

PURPOSE: The purpose of this study was to evaluate the effects of extraction therapy and use or nonuse of headgear on the soft tissue profile in subjects with different growth patterns. METHODS: A total of 41 subjects were included in the study. The patients were treated with standard edgewise mechanics and had 4 first premolars extracted. The type of growth pattern was assessed as mesiodivergent or hyperdivergent. The results were analyzed by 2-way analysis of variance. RESULTS: When comparing the mean changes between growth pattern types, the vertical changes in Sn and A' were found to be statistically significant (P<.05). The vertical change in A' was also found to be significant between the headgear use and nonuse groups (P<.05). Interaction was found to be significant for Steiner upper and lower lip values and the vertical change in A. The upper and lower lips were retracted significantly more by headgear use in patients with hyperdivergent growth pattern (P<.05). CONCLUSIONS: The results of this study indicate that the use of headgear should be avoided in hyperdivergent patients. The avoidance of premolar extraction, based on the possibility of a significant detrimental effect on the facial profile, is not justified.     

Growth changes in the soft tissue facial profile

Longitudinal growth changes in the soft tissue profile of 40 caucasians between the ages of 7 and 18 were studied. The sample consisted of 17 males and 23 females who had Class I dentitions and balanced faces at age 7 and 18 years. None of the subjects received any orthodontic treatment. Cephalometric radiographs were available, as a rule, on a yearly basis. Soft tissue thickness, measured at the nose, upper lip, lower lip and chin, as well as the length of the upper and lower lip, all increased by varying amounts over the period of the study. Females acquired more growth as a percentage of their adult size (at age 18) than males in all variables except the angle of inclination of the skeletal chin which increased more in males. The largest increase in relative size was noted in the nose measurements. In males, the nose had not attained adult size even at age 18. Upper lip length growth, on the other hand, in both males and females was complete by the 15th year. The difference between male and female lip length growth was clinically significant; the average aggregate increase in upper and lower lips combined in males was 6.9 millimeters compared to 2.65 millimeters in females. The total gain in thickness at laberale superius was over four times as much in males as in females and continued to increase in males even at age 18. The change in thickness of the soft tissue at pogonion was not large, an average of 2.4 millimeters in males and 1.5 millimeters in females. The major contribution to the anterior growth of the chin was translatory, contributed largely by growth in the skeletal length from pogonion to pterygomaxillary plane.     

Ideal soft tissue facial profile in Iranian females

This study was carried out on 100 photographs of Iranian young adult females, ages ranging from 16 to 40 years. Each photograph was scanned, the image was projected onto a computer monitor, and computerized sketches were obtained from them. With the help of a review committee, 10 of the best sketches were selected and analyzed. The linear and angular measurements were made to the nearest 0.5 mm with dial calipers and a standard protractor with 0.5 mm increments. A total of 15 measurements were analyzed in the study. Our measurements were compared with North American Caucasian female. The upper and lower lip projections were significantly more prominent in our study. Total facial angle was less prominent in our study in comparison with the North American Caucasian females. These findings led to the conclusion that Iranian females have faces which are more convex than North American Caucasian females. The frontonasal angle was more prominent in our study in comparison with the Farkas study of North American Caucasian females. Other linear and angular measurements did not show significant difference between our study and North American Caucasian females.     

Changes in the soft tissue chin after orthodontic treatment

The study envisages changes in the contour of the soft tissue chin immediately and 5 years after orthodontic treatment in a group of 31 male and 29 female patients. The group was classified according to facial types and whether treatment involved extraction of first premolar teeth. The average age before treatment was 10 years 7 months, immediately after treatment it was 14 years 6 months, and 5 years after treatment was 21 years 6 months. The chin contour was studied from cephalometric x-ray tracings. The facial types--mesofacial, brachyfacial, and dolichofacial--were identified on the basis of cephalometric analysis. The chin thickness was registered at six different locations around the symphysis, from the point on the soft tissue chin corresponding to B point to the chin point corresponding to menton. Statistical means and standard deviations for all of the six chin thicknesses were calculated. It was found that the overall soft tissue chin thickness increased after orthodontic treatment. The females had less increase at all levels than the males. The dolichofacial group showed a greater increase in the soft tissue chin thickness after treatment. The mesofacial and brachyfacial groups of females showed no statistically significant increases. Regression tests of independent variables, including age, sex, facial type, and such other cephalometric measurements as 1 - A Pog, 1 to A Pog, mandibular plane, mandibular arc, facial axis, lower face height, and classification of malocclusion, indicated that age, sex, and facial type were the only variables that influenced the soft tissue chin thickness.     

Comparison of the changes in facial profile after orthodontic treatment,with and without extractions.

Abstract

A study was made of 31 patients with Angle Class II malocclusion. Fifteen patients did not undergo extraction of teeth (Group A), while 16 underwent extractions of four premolars (Group B). Data was obtained from the corresponding lateral radiographs of the head taken both before and after orthodontic treatment. The main aim of the study was to compare the response of the soft and hard tissues of the facial profile in Class II malocclusion treated with the extraction of four premolars and the response of borderline cases presenting with similar malocclusions, but not subjected to extraction. In this latter group reasonable doubt existed as to whether or not to remove teeth in order to solve the occlusal and aesthetic problems. It is concluded that significant hard tissue differences between the groups at the end of treatment were limited to a more retruded position of the incisors and a reduced overbite amongst those patients subjected to extraction. The main soft tissue differences between the groups at the end of treatment were a more retruded lower lip and a more pronounced lower labial sulcus in those patients subjected to extraction.     

Angular photogrammetric analysis of the soft tissue facial profile

All medical specialties interested in improving facial appearance need to measure the face to quantify the desired facial changes. The purpose of this investigation was to obtain objective average measurements of the soft tissue facial profile to use them as a guide for aesthetic treatment goals. The analysis of the soft tissue facial profile from photographic records provides information on the morphology of the profile and its relationship with the underlying dentoskeletal tissues. In this investigation the soft tissue facial profile of a young adult European Caucasian population (212 individual, 50 males and 162 females, 18-20 years of age) was studied by means of standardized photographic records taken in the natural head position (NHP). Angular measurements were analysed digitally. Sexual dimorphism was found for several angles: nasofrontal (G-N-Prn: P < 0.01), vertical nasal (Cm-Sn/N-Prn: P < 0.01), nasal (N-Prn/TV: P < 0.01), nasal dorsum (N-Mn-Prn: P < 0.05), and mandibular contour (C-Me/G-Pg: P < 0.01). Wide individual variations in nasolabial and mentolabial angles were also observed.     

Analysis of soft tissue facial profile in white males

Three of the integumental variables, namely, the total facial convexity, upper lip to esthetic plane, and lower lip length, showed significant measurement errors in the preadolescent boys. Large standard deviations were also found for several variables in both age groups. This suggests that a range of values, rather than means, should be used in clinical cephalometric evaluations. A table of means, standard deviations, and ranges for the variables evaluated is provided. The nasolabial and the mentolabial angles did not differ significantly between the younger and the older age groups. The total soft tissue facial convexity was noted to have a marginally significant difference between the adults and children. Other variables were significantly different between the two age groups, and indicated that the adults had a relatively straighter facial profile than the children. In addition, the upper and lower lips were more retrusive relative to the esthetic plane in adults. Sagittal proportions relating nasal depth/nose to most protrusive lip/chin to most protrusive lip were found to have a ratio of 2.1:1.0:1.2 in children and 1.8:1.0:0.3 in adults.     

Predicting soft tissue profile changes concurrent with orthodontic treatment

Two studies related to soft tissue profile change, are reported in this paper. In the first study, 50 adults with normal occlusion were compared to 50 adults with maxillary protrusion. Cephalometric radiographs were obtained for all subjects in two positions: with lips relaxed and lips closed. The amount of lower lip movement increased in relation to the degree of maxillary protrusion. In both groups, thickness of soft tissue pogonion decreased with upward movement of the lower lip. In the second study, 20 posttreatment patients were examined to determine how soft tissue profile is related to the morphologic alterations of treatment. Ten patients were treated for maxillary protrusion and 10 for bimaxillary protrusion. Upper lip retraction was about 40 percent of the maxillary incisor retraction. Cases with maxillary protrusion showed slightly less soft tissue change than cases with bimaxillary protrusion. Lower lip retraction was about 70 percent of the maxillary incisor retraction. With an understanding of pretreatment lip posture and data related to the soft tissue response to treatment, a framework is presented for predicting a patient's posttreatment facial profile.     

Microcracks in the alveolar bone following orthodontic tooth movement: a morphological and morphometric study

Microcracks and microdamage have been associated with bone remodelling. The aim of this study was to investigate the role of microcracks as a trigger for alveolar bone remodelling after the application of an orthodontic load. In 25 3-month-old male Danish land-race pigs, the lower right first molar was moved buccally with a force of 130 cN. The contralateral molar was not treated and was used as an internal control. After 1, 2, 4, 7 and 15 days of treatment, the regions containing the right and left molars were excised and en bloc stained in basic fuchsin. The presence of microcracks on the buccal and lingual sides of both treated and untreated teeth was detected and expressed as crack density (number/mm2). The buccal treated side showed significantly more cracks than the buccal untreated side at day 1. This difference was significantly larger than that observed at days 2, 7 and 15. The same side showed significantly more microcracks than the lingual treated side at day 1, and this difference was larger compared with that observed at days 4 and 15. The presence of more microcracks on the treated side than on the untreated side suggests a role for microcracks in the initiation of bone remodelling after orthodontic loading. The increased presence of microcracks on the side towards which the tooth was moved, and where bone resorption is usually observed, suggests that microcracks could represent the first damage induced by orthodontic force that has to be repaired by bone remodelling. Finally, the strain levels in the alveolar bone during the orthodontic load transfer in the experiment were examined by finite element (FE) analysis. Although this showed that the strains were very low (10-100 microstrain), it should be noted that occlusal loading was not taken into account. In addition, high-resolution microtomography of the alveolar bone/periodontal ligament (PDL) interface revealed that the actual surface of the alveolar bone was very rough, predisposing it to high local stress/strain peaks.     

Linear photogrammetric analysis of the soft tissue facial profile.

This study digitally analyzes the soft tissue facial profile of a European white population of young adults by means of linear measurements made on standardized photographic records taken in natural head position. The application of the Student t test showed sexual dimorphism in most parameters of the labial, nasal, and chin areas. In general, males had greater heights and lengths as well as greater prominences of these 3 areas. They also had greater nasal and facial depths at the level of the tragus point.     

Significance of the soft tissue profile on facial esthetics.

The soft tissue profile has been studied extensively in orthodontics, primarily from lateral cephalometric radiographs, under the assumption that the form of the soft tissue outline largely determines the esthetics of the whole face. The purpose of this study was to assess the relative contribution of the shape of the soft tissue profile outline on the attractiveness of the face, as seen from the profile view. Pretreatment color profile facial photographs of 20 female patients were used. The photographs were scanned, and the soft tissue outlines were digitized. The average outline of the 20 original photographs was then calculated and used as a template for modifying the photographs with computer warping methods. This resulted in 20 warped photographs, all with the same soft tissue outline. Three additional photographs were constructed with 1 face-the composite average of the 20 original photographs-and 3 hairstyles from 3 of the original pictures. The photographs were printed and presented to 10 laypersons and 10 orthodontists for scoring. Scoring was performed on 2 occasions separated by at least 1 week. On the first occasion, the original photographs of 10 of the patients and the warped photographs of the other 10 patients were shown. At the next session, the remaining 10 original and 10 warped photographs were shown. The 3 composite photographs were interspersed with the 20 pictures shown to the judges in each scoring session. Judges were asked to score facial attractiveness on a scale of 0 to 10. The judges were unaware of both the computer modification of the photographs and the purpose of the study. Good agreement was noted between the judges, although the orthodontists tended to be more influenced by the profile outline than did the laypersons. The 3 averaged composite photographs were consistently given the highest scores. The modified photographs were given higher scores than their original counterparts, showing that facial attractiveness is influenced by soft tissue outline form. However, the score improvement was not sufficient to reach the level of the composite images, especially for faces initially judged as being unattractive. This shows that factors other than profile outline shape may be more influential in facial esthetics.     

正畸治疗对软组织侧貌的影响

在寻求牙列整齐的正畸患者中,也存在一部分对面容有需求的患者。另一方面,正畸医师在制定治疗计划时,软组织侧貌的考虑也会影响矫治设计。本文就软组织侧貌的评价方式、各种正畸手段如功能性矫治器、拔牙矫治等对软组织侧貌的影响以及研究进展进行综述。     

Three-dimensional facial morphometric assessment of soft tissue changes after orthognathic surgery

OBJECTIVE: In this study, a 3-dimensional system with landmark representation of the soft tissue facial surface was applied for the evaluation of facial changes occurring after orthognathic surgery in 5 patients. StUDY DESIGN: Standardized facial landmark acquisitions were performed before and 1 year after surgery (combined maxillary Le Fort I and sagittal mandibular osteotomies). The 3-dimensional coordinates of 22 facial soft tissue points were collected on each subject through use of a computerized noninvasive method and used to calculate a set of selected parameters. RESULTS: Three-dimensional soft tissue analysis of patients was in general agreement with the type of surgery performed, with volumetric contraction of the lower facial third and expansion of the middle facial third. Moreover, negative effects of surgery were quantified (eg, an increase in alar base dimensions); the global asymmetry of facial soft tissues was increased by intervention, but asymmetry in the lower facial third was reduced. CONCLUSIONS: The method used in this study proved useful as a complementary diagnostic aid, enabling quantitative evaluation of the final soft tissue results of surgery, which were proportional to those expected on the basis of the type of treatment and skeletal data.     

Changes in the facial profile following insertion of complete dentures

The effect of the topography of prostheses on the facial profile is poorly understood. This study was undertaken to identify changes in the facial profile, following insertion of dentures. The maxillary denture produced a more dominant effect than the mandibular, the greatest change affecting the philtrum and lips. The evidence also supports the concept that the tip of the upper incisors supports the lower lip. The actual length of facial tissues between selected landmarks in the midline did not change measurably following insertion of dentures in the rest position. A relationship between soft tissue shift and the known thickness of denture base was found for three landmarks, however, it was not possible to predict the size of these changes for other thicknesses of denture base with confidence.