Soft tissue adaptability to hard tissues in facial profiles

Accuracies of facial soft tissue depth means for estimating ground truth skin surfaces in forensic craniofacial identification

Facial soft tissue thickness means have long been used as a proxy to estimate the soft tissue envelope, over the skull, in craniofacial identification. However, estimation errors of these statistics are not well understood, making casework selection of the best performing estimation models impossible and overarching method accuracies controversial. To redress this situation, residuals between predicted and ground truth values were calculated in two experiments: (1) for 27 suites of means drawn from 10 recently published studies, all examining the same 10 landmarks (N ≥ 3051), and tested against six independent raw datasets of contemporary living adults (N = 797); and (2) pairwise tests of the above six, and five other, raw datasets (N = 1063). In total, 380 out-of-sample tests of 416 arithmetic means were conducted across 11 independent samples. Experiment 1 produced an overarching mean absolute percentage error (MAE) of 29% and a standard error of the estimate (S(est)) of 2.7 mm. Experiment 2 yielded MAE of 32% and S(est) of 2.8 mm. In any instance, MAE was always ≥20% of the ground truth value. The overarching 95% limits of the error, for contemporary samples, was large (11.4 mm). CT-derived means from South Korean males and Black South African females routinely performed well across the test samples and produced the smallest errors of any tests (but did so for Black American male reference samples). Sample-specific statistics thereby performed poorly despite discipline esteem. These results—and the practice of publishing means without prior model validation—demand major reforms in the field.

Correlation between objective and subjective evaluation of profile in bimaxillary protrusion patients after orthodontic treatment

OBJECTIVE

To correlate the objective cephalometric measurements with subjective facial esthetics in patients with bimaxillary protrusion.

MATERIALS AND METHODS

The sample consisted of 60 Asian-Chinese patients with bimaxillary protrusion who met the inclusion criteria. The facial esthetics of posttreatment profile and the change of profile on standardized lateral photographs were rated by a panel of 10 orthodontists and a panel of 10 lay persons with bimaxillary protrusion. All of the pretreatment and posttreatment cephalograms were digitized and traced. Twenty-five cephalometric measurements were constructed and analyzed. Correlations between the subjective facial esthetic scores and each cephalometric measurement were evaluated.

RESULTS

The cephalometric measurements correlated with the facial esthetic scores of posttreatment profile given by the orthodontist and the lay persons were basically the same. For the evaluation of posttreatment profile in bimaxillary protrusion patients, the upper and lower lip to E-line, upper and lower incisor tip to AP plane, Pg-NB distance, mentolabial angle, and sulcus depth correlated significantly with the esthetic score. For the evaluation of profile change during orthodontic treatment, retraction of upper incisor relative to AP plane or the perpendicular line through sella (line Y), change of upper incisor inclination, change of mentolabial sulcus depth, and retraction of lips relative to E-line were correlated positively with the esthetic value.

CONCLUSIONS

Cephalometric measurements of lip position, incisor position, and chin morphology were key parameters correlated to facial esthetics.

Measurement of three-dimensional perioral soft tissue changes in dentoalveolar protrusion patients after orthodontic treatment using a structured light scanner

OBJECTIVE

To evaluate the three-dimensional (3D) perioral soft tissue changes after orthodontic treatment in patients with dentoalveolar protrusion using structured light-based scanners.

MATERIALS AND METHODS

Forty-four Korean adults (19 men and 25 women, 21.4 ± 3.4 years) with dentoalveolar protrusion treated by extraction of all four first premolars and then en masse retraction with maximum anchorage were evaluated. Lateral cephalograms and 3D facial scans were obtained before treatment (T1) and immediately after debonding (T2). Superimposition was performed, and 27 perioral landmarks were identified. The 3D changes in the landmarks and ratio of movement of the soft tissue relative to the horizontal incisal tip were evaluated. A paired t-test and one-way analysis of variance were performed.

RESULTS

The upper incisors were retracted 5.76 mm and the lower incisors were retracted 4.62 mm (P < .001). The upper lip moved inferoposteriorly, and the lower lip moved superoposteriorly. In the lower lip, upward movement was greater than backward movement (P < .001). The most prominent changes appeared at the greatest bulge area. The relative ratios were 42%-53% in the upper lip area and 22%-82% in the lower lip area. The lip corners moved superoposteriorly (P < .001). Subnasale moved downward (P < .05) and posteriorly (P < .001), while the landmarks under the nostrils moved upward and posteriorly (P < .001).

CONCLUSION

Facial scans from white structured light scanners efficiently evaluated 3D perioral soft tissue in dentoalveolar protrusion patients. Backward movement and significant vertical movement of the lip were observed. The nasal and lip angle areas showed considerable changes.

The application of the central limit theorem and the law of large numbers to facial soft tissue depths: T-Table robustness and trends since 2008

By pooling independent study means (x¯), the T-Tables use the central limit theorem and law of large numbers to average out study-specific sampling bias and instrument errors and, in turn, triangulate upon human population means (μ). Since their first publication in 2008, new data from >2660 adults have been collected (c.30% of the original sample) making a review of the T-Table's robustness timely. Updated grand means show that the new data have negligible impact on the previously published statistics: maximum change = 1.7 mm at gonion; and ≤1 mm at 93% of all landmarks measured. This confirms the utility of the 2008 T-Table as a proxy to soft tissue depth population means and, together with updated sample sizes (8851 individuals at pogonion), earmarks the 2013 T-Table as the premier mean facial soft tissue depth standard for craniofacial identification casework. The utility of the T-Table, in comparison with shorths and 75-shormaxes, is also discussed.

Three-dimensional soft-tissue and hard-tissue changes in the treatment of bimaxillary protrusion

INTRODUCTION

Facial convexity related to bimaxillary protrusion is prevalent in many populations. Underlying skeletal protrusion combined with increased dentoalveolar protrusion contributes to facial muscle imbalance and lip incompetence, which is undesirable for many patients. In this study, we evaluated the relationship between soft-tissue and hard-tissue changes in an orthodontically treated Asian population.

METHODS

Twenty-four consecutive adult Asian patients (mean age, 24 years), diagnosed with severe bimaxillary dentoalveolar protrusion, were evaluated using pretreatment and posttreatment cone-beam computed tomography. The patients were treated with 4 first premolar extractions followed by anterior retraction with either skeletal or intraoral anchorage. Serial cone-beam computed tomography radiographs were registered on the entire cranial base and fossa. Soft-tissue and hard-tissue changes were determined through landmark displacement and color mapping.

RESULTS

Upper lip retraction was concentrated between the nasolabial folds and commissures. Lower lip retraction was accompanied by significant redistribution of soft tissues at pogonion. Soft-tissue changes correlated well with regional facial muscle activity. Significant retractions (2-4 mm) of the soft tissues occurred beyond the midsagittal region. Use of skeletal anchorage resulted in 1.5 mm greater lower lip retraction than intraoral anchorage, with greater retraction of the maxillary and mandibular incisor root apices.

CONCLUSIONS

Profound soft-tissue changes accompanied retraction of the anterior dentition with both treatment modalities.

Facial soft tissue depth statistics and enhanced point estimators for craniofacial identification: the debut of the shorth and the 75-shormax

Several methods that have customarily been used in craniofacial identification to describe facial soft tissue depths (FSTDs) implore improvement. They include the calculation of arithmetic means for skewed data, omission of concern for measurement uncertainty, oversight of effect size, and misuse of statistical significance tests (e.g., p-values for strength of association). This paper redresses these limitations using FSTDs from 10 prior studies (N = 516). Measurement uncertainty was large (>20% of the FSTD), skewness (≥ 0.8) existed at 11 of the 23 FSTD landmarks examined, and sex and age each explained <4% of the total FSTD variance (η(2) calculated as part of MANOVA). These results call for a new and improved conceptualization of FSTDs, which is attained by the replacement of arithmetic means with shorths and 75-shormaxes. The outcomes of this implementation are dramatic reduction in FSTD complexity; improved data accuracy; and new data-driven standards for casework application of methods.

The influence of lower lip position on the perceived attractiveness of chin prominence

OBJECTIVES

To evaluate the influence of the lower lip prominence for varying degrees of chin prominence in the sagittal plane and to establish whether lower lip prominence affects the perceived desire for surgery. To assess differences in preference between orthodontists and laypeople as well as the effect of age, gender, and ethnicity of observers on perceptions of attractiveness and desire for surgery.

MATERIALS AND METHODS

A silhouette of an idealized profile image was created. The image was manipulated to create six images demonstrating different degrees of retrogenia and progenia altered in 4-mm increments from -12 mm to +12 mm and six images demonstrating chin and lower lip prominence in 4-mm increments from -12 mm to +12 mm. One hundred laypeople and 30 orthodontists ranked the images from the most to the least attractive. A duplicate of one of the images was used in order to assess intraexaminer reliability.

RESULTS

The amount and direction of sagittal chin position and the prominence of the lower lip were found to have a significant effect on image rank. Chin protrusion was less attractive than retrusion and surgery was desired more often for these images. The overall direction of opinion was the same for laypeople and orthodontists.

CONCLUSIONS

The chin prominence observed in a progenic patient is deemed less attractive than the combined chin and lower lip prominence observed in a patient with mandibular prognathism. In profiles with a more prominent chin a more protrusive lower lip position was preferred. When the chin was retrusive, a normal lower lip position was preferred to a retrusive lip.

Effect of orthodontic treatment on lip position

Does an advanced or retracted position of the upper and lower incisors lead to modifications in lip position? The aim of our study was to evaluate modifications in lip position following orthodontic treatments.

MATERIAL AND METHODS

This study concerned 100 patients who underwent treatment in the dento-facial orthopedic unit in Casablanca. Profile headfilms at the start and at the end of orthodontic treatment were compared using Frapier's analysis. The Student test was applied to evaluate the variations in the cephalometric measurements.

RESULTS

We noted a non-significant increase in the nasolabial angle (P = 0.274), a significant decrease in the sagittal position of the lower vermillion border (PsVei) (P < 0.001) and the sagittal position of the soft-tissue supramentale (PsSmc) (P < 0.001), and a significant increase in the vertical position of the soft-tissue menton (PvMec) (P = 0.035).

CONCLUSION

The results of this study demonstrate marked improvements in the situation of soft tissues. We suggest further investigation to throw light on the relationship between tooth movement and soft tissue, increasing the size of the sample and taking growth into account.

Facial soft tissue depths in French adults: variability, specificity and estimation

Facial soft tissue depths (FSTD) are used in facial approximation to render the shape of the face, and are traditionally published specifically to population, corpulence, and sex amongst other factors. This paper investigates the variability of FSTD collected at 37 landmarks on 500 CT (computed tomography) scans of French living individuals. The specificity of the sample is evaluated by comparing values with six published datasets of various populations and recording techniques. Apart from a significant influence of the corpulence, FSTD show negligible variations with age and sex. The differences between the French sample and other datasets contradict the hypothesis of major influence of population, and underline sample specificity linked with technique and methodology of data measurement. Regression equations were computed to estimate FSTD using age, sex, facial build, and craniometrics, leading to more accurate results if such factors are known. Nevertheless, application of the pooled T-table (Tallied-Facial-Soft-Tissue-Depth-Data) has been validated according to the French sample.

Photographic assessment of cephalometric measurements

OBJECTIVE

To investigate the relationship between craniofacial measurements obtained from cephalometric radiographs and analogous measurements from profile photographs.

MATERIALS AND METHODS

Lateral cephalograms and standardized facial profile photographs were obtained from a sample of 123 subjects (65 girls, 58 boys; age 7-12 years). Intraclass correlation coefficients (ICCs) were calculated from repeated photographic measurements to evaluate method reliability. Analogous cephalometric and photographic measurements were compared to assess Pearson correlation coefficients. Linear regression analyses were conducted between the measurements that achieved correlation coefficients greater than r  =  0.7.

RESULTS

The reliability of the photographic technique was satisfactory. Most measurements showed ICCs above 0.80 and highly significant correlations (P ≤ .001) with cephalometric variables. Among all measurements used, the A'N'B' angle was the most effective in explaining the variability of its analogous cephalometric, mainly for female subjects (r(2)  =  0.80). The FMA' angle showed the best results for vertical assessment (r(2)  =  0.65).

CONCLUSIONS

The photographic method has proven to be a repeatable and reproducible tool provided that a standardized protocol is followed. Therefore, it may be considered a feasible and practical diagnostic alternative, particularly if there is a need for a low-cost and noninvasive method.

Correlation between occlusal abnormalities and parameters investigated by three-dimensional facial photography

Objective:

To clarify, by three-dimensional (3D) facial scans, if 4- to 6-year-old children with intraoral sagittal discrepancies and open-bite occlusion show differences in facial morphology when compared to children without anomalies.

Materials and Methods:

Scans of 290 children presenting with occlusal abnormalities were compared to 1772 face scans of age-matched individuals photographed with a faceSCAN II® 3D data acquisition system. From these, three study groups were formed comprising 188 children with distal occlusion/increased overjet (Class II), 37 with mesial occlusion/inverse overjet (Class III), and 65 with open-bite occlusion. These groups were evaluated by age and gender for each group compared to the control individuals.

Results:

The Class II group showed statistically significant reduced dimensions of head width, upper face width, and midface length. In addition, the mean values for mouth width and lip thickness were higher, and their upper lips were located more anteriorly than in the control group. The Class III group exhibited more markedly retruded upper lips. The facial profile of female 5-year-old Class III patients was significantly more concave. Patients in the open-bite group showed reduced upper lip length, with differences only being statistically significant in male 4-year-olds.

Conclusion:

Dental Class II with increased overjet and dental Class III with decreased overjet influence soft tissue morphology and are represented on 3D facial scans.

Associations between orbicularis oris thickness and skeletal and dental variables in mixed dentition

AIM: To evaluate the association between orbicularis oris thickness and skeletal and dental variables in children with mixed dentition. MATERIAL AND METHOD: A convenience sample of 22 children, aged 7 to 12 years, with skeletal Class I and Class II malocclusion and subdivisions were selected. The upper and lower fascicles of the orbicularis oris thicknesses were measured using ultrasound (US) by one calibrated examiner, at rest and in the contracted state. Cephalometric radiograph measurements of the hard and soft tissues were calculated by one trained examiner. The results were analyzed by the Pearson and Spearman coefficients. RESULT: The upper and lower fascicles of the orbicularis oris in the contracted state showed a negative correlation with the distance between Ricketts' E-line and the labrale superius (E ┴ Ls). There were positive correlations between the lower face height and the distance between the AB plane and the labrale superius (AB-Ls) and between the ANB angle and the distance between E ┴ Ls and Ricketts' E-line and the labrale inferius (E ┴ Li). The lower-incisor distance from the N-Pg plane correlated positively with the distance between AB-Ls and the distance between the E ┴ Ls and E ┴ Li. Overbite and interincisal angle were negatively correlated with the distance between the pogonion and the soft tissue pogonion and the distance between E ┴ Li, respectively. CONCLUSION: Skeletal and dental variables were associated with upper and lower lip position and pogonion thickness, while the upper and lower fascicles of the orbicularis oris thicknesses in the contracted state were associated only with upper lip retrusion.

A more accurate method of predicting soft tissue changes after mandibular setback surgery

PURPOSE

To propose a more accurate method to predict the soft tissue changes after orthognathic surgery.

PATIENTS AND METHODS

The subjects included 69 patients who had undergone surgical correction of Class III mandibular prognathism by mandibular setback. Two multivariate methods of forming prediction equations were examined using 134 predictor and 36 soft tissue response variables: the ordinary least-squares (OLS) and the partial least-squares (PLS) methods. After fitting the equation, the bias and a mean absolute prediction error were calculated. To evaluate the predictive performance of the prediction equations, a 10-fold cross-validation method was used.

RESULTS

The multivariate PLS method showed significantly better predictive performance than the conventional OLS method. The bias pattern was more favorable and the absolute prediction accuracy was significantly better with the PLS method than with the OLS method.

CONCLUSIONS

The multivariate PLS method was more satisfactory than the conventional OLS method in accurately predicting the soft tissue profile change after Class III mandibular setback surgery.

Reference values for three-dimensional surface cephalometry in children aged 3-6 years

OBJECTIVE

This prospective cross-sectional study design was performed to define reference values for the facial surfaces of 3-6-year-old boys and girls using three-dimensional surface cephalometry.

MATERIAL AND METHODS

A total of 2290 standardized three-dimensional facial images from 3 to 6-year-old preschool children were separated by gender and assigned to four age categories. All children were Caucasian and revealed no evidence of dentofacial abnormalities. On each image, 31 cephalometric landmarks were marked, resulting in 35 (19 frontal, six lateral, 10 paired) distances and eight angles. Differences between age groups and genders were calculated and significances detected.

RESULTS

A base table with reference values was compiled, which indicated that boys showed higher values than age-matched girls and that measured distances increased with age.

CONCLUSION

The mean values from this study could be compiled as a reference table for three-dimensional facial analysis in Caucasian children aged 3-6 years. Such a reference table could be used in comparative studies with other populations or children with craniofacial malformations.

Midline facial soft tissue thickness database of Turkish population: MRI study

Facial reconstruction is the approximation of an antemortem face from human skeletal remains. Since the nineteenth century, several methods have been developed for reconstruction of the face; all of them require the measurement of average tissue thicknesses at various points on the face. To our knowledge, there are no publications on soft tissue thickness in the Turkish population. In addition, there are few publications on the value of magnetic resonance imaging (MRI) in measuring soft tissue thickness for forensic sciences. The aim of this study was to create a reference database of facial tissue thickness in the Turkish population, and to present data illustrating the successful use of MRI for this purpose. The study included 161 patients (79 males and 82 females) between the ages of 18 and 78 who had undergone brain MRI in our radiology clinic, and showed no sign of maxillofacial pathology. Measurements were taken at 9 points at the midline; glabella, nasion, end of nasals, mid-philtrum, upper lip margin, lower lip margin, chin-lip fold, mental eminence, and beneath chin points. The mean values for these points in the patient sample population were determined, and differences related to age, sex, and body mass index (BMI) were calculated. The values were then compared to the findings of the Manhein study.

Long-term occlusal and soft-tissue profile outcomes after treatment of Class II Division 1 malocclusion with fixed appliances

INTRODUCTION

Our objective was to determine which factors were predictive of good long-term outcomes after fixed appliance treatment of Class II Division 1 malocclusion.

METHODS

Two hundred seven patients with Class II Division 1 malocclusion were examined in early adulthood at a mean of 4.6 years after treatment with fixed appliances. The peer assessment rating index was used to evaluate dental alignment and occlusal relationships. The soft-tissue profile was assessed with the Holdaway angle.

RESULTS

Logistic regression identified 3 pretreatment variables that were predictive of a good facial profile (Holdaway angle) at recall: the lower lip to E-plane distance (P <0.001; smaller distance behind the E-plane means a better outcome), ANB angle (P = 0.001; smaller ANB means a better outcome), and extraction pattern (P = 0.026). Linear regression analysis showed that 2 pretreatment variables were predictive of a favorable PAR score at recall: SNB angle (P = 0.001; larger SNB means a better outcome) and extraction pattern (P = 0.034).

CONCLUSIONS

Three pretreatment cephalometric measures (lower lip to E-plane distance, ANB angle, and SNB angle) were predictive of the outcome in the treatment of Class II Division 1 malocclusion. The extraction pattern was also found to be a predictor of outcome.

Soft tissue changes following the extraction of premolars in nongrowing patients with bimaxillary protrusion. A systematic review

OBJECTIVE

To quantify the amount of perioral tissue changes following the extraction of four premolars in patients with bimaxillary protrusion who had nearly completed active growth.

MATERIALS AND METHODS

A literature search was conducted to identify clinical trials that assessed cephalometric perioral soft tissue changes in patients affected by biprotrusion and treated with extractions. Electronic databases (PubMed, ISI WoS Science Citation Index Expanded, and HubMed) were searched. Abstracts that appeared to fulfill the initial selection criteria were selected, and the full-text original articles were retrieved and analyzed. Only articles that fulfilled the final selection criteria were finally considered. Their references were also hand-searched for possible missing articles from the database searches.

RESULTS

Nine abstracts met the initial inclusion criteria and these articles were retrieved. From these, five were later rejected mostly because the sample dealt with growing subjects. Four articles remained and they showed that the upper and lower lips retracted and the nasolabial angle increased following premolar extraction. Upper lip retraction ranged from 2 mm to 3.2 mm, lower lip retraction ranged from 2 mm to 4.5 mm.

CONCLUSIONS

The lip procumbency improves following the extraction of four premolars and this improvement is predictable. However, the changes are small and do not dramatically modify the profile. A "dished in" profile is not to be expected. Individual variation in response is large.

A nonradiographic approach to detect Class III skeletal discrepancies

INTRODUCTION

Because of the hereditary nature of Class III malocclusion, relatives of affected subjects often ask for a consultation. To estimate the degree of skeletal manifestation without exposing them to radiation, an alternative to lateral cephalograms would be valuable for preliminary diagnosis. Thus, we aimed to assess the validity of profile photographs to detect skeletal Class III discrepancy.

METHODS

Profile photographs and lateral cephalograms were available from 42 young white men, 29 with Class III malocclusion and 13 with Class I. A computer-based analysis was performed including hard-tissue variables on cephalograms and soft-tissue variables on photographs

RESULTS

Soft-tissue facial characteristics showed strong correlations with several skeletal structures of skeletal Class III subjects (r > or = 0.7, P < 0.001). Thus, soft-tissue A'N'B', A'N'Pog', and N'A'/A'Pog' were highly related to skeletal ANB, ANPog, and NA/APog. Vertically, soft- and hard-tissue lower anterior face heights were strongly correlated. A soft-tissue A'N'B' angle of 6 degrees is the critical value below which skeletal Class III can be implied (sensitivity, 90.5%; specificity, 81.0%). This finding was validated among female subjects.

CONCLUSIONS

A profile photograph can show with high probability a skeletal Class III discrepancy and might be useful for diagnosis during the initial consultation.

Prediction of lip response to four first premolar extractions in white female adolescents and adults

OBJECTIVE

To develop models for predicting changes in lip position of Class I extraction patients.

MATERIALS AND METHODS

Pretreatment and posttreatment lateral cephalograms of 46 white female adults and 109 white female adolescents were examined. Mean pretreatment ages for the adolescent and adult groups were 12.2 +/- 1.2 years and 23.0 +/- 8.5 years, respectively. Subjects were treated with conventional edgewise mechanics. Multivariate prediction models were derived from a randomly selected sample of 119 subjects and validated on the remaining 36 subjects.

RESULTS

Adolescents demonstrated significant vertical and horizontal skeletal growth and treatment changes, while adults showed only small increases in anterior face height. While significant retraction of the upper and lower incisors occurred in both groups, the amounts were greater in adults than in adolescents. Ratios for horizontal hard tissue to soft tissue movements ranged from 1.4:1 to 1.1:1 and 1.3:1 to 1:1 for the upper (Ls) and lower (Li) lips, respectively. There were moderate relationships between horizontal lip and underlying hard tissue movements (correlations ranged from .57 to .78 for Ls and from .58 to .86 for Li). Multiple regressions to predict lip movements showed moderately strong relationships for the upper lip (R = .79 to .81) and strong relationships for the lower lip (R = .89 to .90). Two to three variables were necessary to predict vertical lip movements (R = .82 to .87). The validation sample showed no systematic biases and similar levels of accuracy.

CONCLUSIONS

Upper and lower lip retraction in four first premolar extraction cases can be predicted with moderately high levels of accuracy in white female adolescents and adults.

AP relationship of the maxillary central incisors to the forehead in adult white females

OBJECTIVE

To evaluate and compare the anteroposterior relationship of the maxillary central incisors to the forehead in adult white females with harmonious profiles and in adult white female orthodontic patients.

MATERIALS AND METHODS

Ninety-four photographic images of adult white females with good facial harmony (control sample) were compared with 94 photographs of adult white females seeking orthodontic treatment (study sample). All images were of the face in profile with the maxillary central incisors and the forehead in full view. The images were scanned, resized, and rotated to the upright head position. Reference lines were constructed to assess the anteroposterior positions of the maxillary central incisors as well as forehead inclinations.

RESULTS

In the control sample, 93% had maxillary central incisors positioned between the FFA point and glabella, 4% posterior to the FFA point, and 3% anterior to glabella. The positions of the maxillary central incisors were strongly correlated with forehead inclination (r2 = .642). In the study sample, 21% had maxillary central incisors positioned between the FFA point and glabella, 64% posterior to the FFA point, and 15% anterior to glabella. The positions of the maxillary central incisors were poorly correlated with forehead inclination (r2 = .094). The difference between the means for anteroposterior maxillary incisor position was statistically significant (P = .0001).

CONCLUSION

The forehead is an important landmark for anteroposterior maxillary incisor positioning for adult white female patients seeking improved facial harmony.

Facial soft tissue depths in craniofacial identification (part I): An analytical review of the published adult data

With the ever increasing production of average soft tissue depth studies, data are becoming increasingly complex, less standardized, and more unwieldy. So far, no overarching review has been attempted to determine: the validity of continued data collection; the usefulness of the existing data subcategorizations; or if a synthesis is possible to produce a manageable soft tissue depth library. While a principal components analysis would provide the best foundation for such an assessment, this type of investigation is not currently possible because of a lack of easily accessible raw data (first, many studies are narrow; second, raw data are infrequently published and/or stored and are not always shared by some authors). This paper provides an alternate means of investigation using an hierarchical approach to review and compare the effects of single variables on published mean values for adults whilst acknowledging measurement errors and within-group variation. The results revealed: (i) no clear secular trends at frequently investigated landmarks; (ii) wide variation in soft tissue depth measures between different measurement techniques irrespective of whether living persons or cadavers were considered; (iii) no clear clustering of non-Caucasoid data far from the Caucasoid means; and (iv) minor differences between males and females. Consequently, the data were pooled across studies using weighted means and standard deviations to cancel out random and opposing study-specific errors, and to produce a single soft tissue depth table with increased sample sizes (e.g., 6786 individuals at pogonion).

Soft-tissue changes during facial growth in skeletal Class II individuals

INTRODUCTION

In orthodontic treatment, a harmonious soft-tissue profile can be difficult to achieve; the thickness of the soft tissues can vary greatly, and changes with growth and treatment can be difficult to predict. The purpose of this study was to investigate changes in the thickness and the length of the soft tissues of the nose, upper and lower lips, and chin due to growth from 6 to 16 years of age.

METHODS

Cephalograms of 36 subjects (22 boys, 15 girls) with skeletal Class II malocclusions were analyzed. They participated in the Burlington Growth Study, and longitudinal records had been collected at ages 6, 9, 12, 14, and 16 years. The cephalograms were digitized and analyzed with Dentofacial Planner Plus (version 2.0; Dentofacial Software, Toronto, Ontario, Canada) software. Statistical analysis was performed with the nonparametric Friedman test, and comparisons among means were made with 1-way ANOVA software.

RESULTS

All structures showed some growth at all stages. The nose showed the greatest increases in thickness and length in both sexes. There was sexual dimorphism at 16 years, with higher values for boys. Upper lips tended to reduce in the girls. Upper lip length showed slight increases, and base of the upper lip showed small increases for both sexes. The lower lip had moderate increases in all measurements, and its thickness showed sexual dimorphism at almost all ages. The soft tissues of the chin increased in both thickness and length, with no sexual dimorphism.

An alternative soft tissue analysis following mandibular setback by sagittal split ramus osteotomy

OBJECTIVE

The objective of this study was to determine alternative ratios of soft-to-hard tissue movement after mandibular setback, taking skeletal relapse and differing patterns of facial divergence into account.

STUDY DESIGN

Thirty patients were analyzed cephalometrically over a mean follow-up period of 14 months.

RESULTS

The relationship between skeletal and soft tissue movements in the mentolabial folds and at the pogonion was 1:1. Final skeletal relapse was 0.8 mm at the B-point and 0.5 mm at the pogonion. Hence, the alternative ratios were 81% and 68%, respectively. The alternative ratio for the mentolabial sulcus was considerably lower in the low- than in the high- and medium-angle groups of patients. However, there was no statistically significant difference between the patient groups with different facial patterns.

CONCLUSION

When the smallness of the measured relapse and the tracing error are taken into account, the difference between the alternative and the conventional ratios was insignificant.

The effects of computer-aided anteroposterior maxillary incisor movement on ratings of facial attractiveness

BACKGROUND

Before planning orthodontic treatment, it is necessary to understand societal preferences for facial esthetics. The anteroposterior (AP) position of the maxillary incisors affects the appearance of the soft tissue profile and can be manipulated by orthodontic techniques. To improve the ability to predict the most suitable maxillary incisor position, numerous cephalometric and profilometric measurements have been suggested. Among them are the Six Elements to Orofacial Harmony proposed by L. F. Andrews, whereby forehead angulation is used to dictate maxillary incisor sagittal position. Our aim was to evaluate differences in preference for the AP position of the maxillary incisor between orthodontic and lay panels.

METHODS

A smiling profile photograph was taken of a female subject who best fit the chosen soft tissue normative values and whose maxillary incisors were in an Element II position. The photograph was manipulated to simulate maxillary protrusion and retrusion at 1-mm increments to a maximum of +/-4 mm. Panels of orthodontists and nonorthodontists scored the attractiveness of the photographic variations according to a 100-mm visual analogue scale.

RESULTS

The 4-mm retrusive photograph was significantly less desirable than all others, which suggests that, from an esthetic standpoint, it is preferable to either leave a normally protrusive maxillary dentition where it is or advance rather than retract the maxillary anterior teeth. Orthodontic training did not significantly affect the magnitude of the ratings or pattern of preference in our sample.

CONCLUSIONS

Andrews' Element II provides an additional useful method to evaluate attractiveness relative to the maxillary incisor position.

M, Marcantonio É. Alterações no perfil dos lábios de pacientes submetidos a avanços maxilares em cirurgia ortognática do tipo Le Fort I

A literatura que descreve os resultados das correções cirúrgicas nos tecidos moles é limitada, pois apresenta significativa variação e não oferece conclusões definitivas. O propósito desse artigo é estudar retrospectivamente os efeitos das cirurgias ortognáticas maxilares tipo Le Fort I nos lábios superiores e inferiores de pacientes adultos e discutir os potenciais problemas envolvidos com a metodologia aplicada. Foram estudados 19 pacientes brancos de 19 a 42 anos de idade, sendo 10 homens e 9 mulheres, submetidos a cirurgias maxilares no Centro de Pesquisa e Tratamento das Deformidades Buco-Faciais - CEDEFACE (Araraquara, SP). A grande maioria dos casos apresentou, no mínimo, uma discrepância significativa, seja ântero-posterior ou vertical, reforçando a sua indicação cirúrgica. As alterações nos tecidos moles foram significativas quando as movimentações horizontais ou verticais da base óssea maxilar foram significativas, com uma relação de aproximadamente 0,6:1 entre as alterações ântero-posteriores do lábio superior e a movimentação da base óssea. Alterações verticais na maxila, sem significativas alterações horizontais, não foram suficientes para aumentar verticalmente o lábio superior. Ocorreram alterações ântero-posteriores do lábio inferior em conseqüência do deslocamento anterior e inferior da maxila, o que permitiu um melhor selamento labial. Alterações verticais não foram quantificadas no lábio inferior.

Changes in mandibular incisor position in Class II Division 1 malocclusion treated with premolar extractions

The aim of this study was to investigate the magnitude of mandibular incisor retraction to be expected during full fixed appliance mechanotherapy in Class II Division 1 malocclusions treated with premolar extractions when mandibular incisor retraction was not part of the treatment plan. The material consisted of pretreatment and posttreatment cephalometric films and dental casts of 70 Class II Division 1 malocclusion patients (33 males and 37 females) treated with the preadjusted edgewise appliances. The mandibular first premolars were extracted in 31 subjects, and the mandibular second premolars were extracted in 39. The pretreatment factors that suggested a basis for the extraction choice in the mandibular arch in these patients were found to include the ratio between posterior and anterior facial heights, the maxillary-mandibular plane angle, and the residual space in the mandibular arch. The mandibular incisors were retracted in only 65% of the patients. On average, the mandibular incisors were retracted by 1.02 mm relative to the nasion-pogonion line; there was no significant difference between the 2 extraction groups. Multiple regression analysis showed that the change in the mandibular incisor position is significantly correlated with the residual space in the mandibular arch, the initial distance between the mandibular incisor and the nasion-pogonion line, maxillary-mandibular angle, and the duration of crown labial torque in the mandibular incisors. In combination, these 4 factors could explain 61% of the change in the mandibular incisor position.

Morphospatial analysis of soft-tissue profile in patients with Class II Division 1 malocclusion treated using twin block appliances: geometric morphometrics

OBJECTIVES

To study soft-tissue profile changes in patients treated with twin block appliances (TBA) for the correction of Class II division 1 malocclusion. The null hypothesis is that soft-tissue profiles do not show any significant improvements associated with TBA treatment.

DESIGN

Longitudinal, retrospective.

SETTING AND SAMPLE POPULATION

Scotland, UK, using lateral cephalographs of 46 consecutive, prepubertal children (aged 9-11 years) and 55 adolescents (aged 12-14 years) obtained from an orthodontic practice.

EXPERIMENTAL VARIABLE

The prepubertal children underwent = 13 months of TBA treatment, while the adolescents underwent = 22 months of treatment.

OUTCOME MEASURES

Configurations of 13 digitized homologous landmarks of pre- and post-treatment soft-tissue facial profiles were compared using cephalometry, Euclidean distance matrix analysis (EDMA) and thin plate spline (TPS) analysis.

RESULTS

Cephalometry showed that height increases associated with the TBA were in the labiomental areas, and the most significant height decreases were seen in the lip regions. The results of EDMA also indicated significant changes (P < 0.05). The distance between the lips decreased by >5%, with increases in length in the labiomental region. The TPS analysis showed the soft-tissues of the mandibular complex being displaced anteroinferiorly, with anterior displacement of the landmarks of the lip region. These changes showed that the lips were brought into closer proximity with each other, permitting a functional oral seal. Moreover, the labiomental groove became less pronounced, reflecting the underlying dento-alveolar correction.

CONCLUSION

Demonstrable improvements in soft-tissue facial profile may be associated with TBA treatment.

Soft tissue profile changes after autogenous iliac crest onlay grafting for the extremely atrophic maxilla

PURPOSE

The aim of this study was to evaluate profile changes in the hard and soft tissues after onlay grafting in the extremely atrophic maxilla.

PATIENTS AND METHODS

Onlay grafting using autogenous iliac crest bone grafts was performed in 49 patients (42 females and 7 males) with extreme atrophy of the edentulous maxilla (vertical amount of bone: <6 mm, transverse amount of bone: <5 mm). For the assessment of the changes to the hard and soft tissues, the preoperative and postoperative cephalograms were traced and the cephalometric measuring points (44 skeletal and 25 soft tissue points) were digitalized with the aid of the Dentofacial Planner System. Evaluation of a relationship between soft tissue and hard tissue profile changes was performed by comparing the movement of the skeletal points Sub-ANS and A-point with the shift of the soft tissue point SLS. To determine significant hard tissue and soft tissue changes, the measured values were evaluated using the SPSS program system and examined for statistical significance by use of the Wilcoxon test.

RESULTS

An advancement of the bony maxilla profile in the sagittal direction by an average of 2.4 mm (P < .01) was found. The soft tissue profile of the upper lip was moved forward on average by 2.3 mm (P = .0039) at the superior labial sulcus point and by 2.7 mm (P = .0018) at the labrale superius point. The ratio of the soft tissue change to hard tissue change was 0.7:1 (superior labial sulcus: skeletal point sub-ANS) or 0.9:1 (superior labial sulcus: A point).

CONCLUSIONS

When planning onlay graft operations, consideration should be given to the functional and aesthetic effects of the profile changes on the upper lip.