Analysis of facial soft tissue values and cranial skeletal widths in different body mass index percentile adolescent subjects

Facial soft tissue thickness measurement method and relationship with BMI, age and sex

INTRODUCTION

Facial aesthetics results from the harmony of various components of the craniofacial region, a structure whose physiognomy and topography are determined by a set of hard and soft tissues. Few works in the literature have investigated the relationship between the variables of sex, age, BMI and soft tissue thickness and have considered how these variables may influence operative outcomes. The purpose of this study is to increase the pre-operative knowledge of the thickness of the soft tissues of the face through an analysis of their measurement conducted on cone beam computed tomography (CBCT) and to investigate the impact that the variables of gender, age and BMI have on their determination.

MATERIALS AND METHODS

For this study 82 patients were recruited between January 2020 and January 2021 in the Department of Maxillofacial Surgery of the University of Naples "Federico II". A descriptive analysis of the sample was carried out on the selected sample, calculating averages and standard deviations for the individual variables analyzed.

RESULTS

BMI has a predominant role on some craniometric points while age and sex have a more marginal role. Our analysis shows that some points are affected by only one variable, BMI (G' N' PR' ID' SM' GN' PG' MIO' ACP' GO' ZY' SC' IC' ECMS' and MMB'); some points are affected by both BMI and gender (MP' and MR'); while only two (RHI' and MSO') are influenced by all the three variables.

CONCLUSION

A priori knowledge through CBCT of the thickness of the soft tissues of the face and a comparison with the data we propose could provide the surgeon with advance notice of the characteristics of the tissues which she/he will encounter.

Association of Body Mass Index (BMI) with Lip Morphology Characteristics: A Cross-Sectional Study Based on Chinese Population

BACKGROUND

Lip morphology is essential in diagnosis and treatment of orthodontics and orthognathic surgery to ensure facial aesthetics. Body mass index (BMI) has proved to have influence on facial soft tissue thickness, but its relationship with lip morphology is unclear. This study aimed to evaluate the association between BMI and lip morphology characteristics (LMCs) and thus provide information for personalized treatment.

METHODS

A cross-sectional study consisted of 1185 patients from 1 January 2010 to 31 December 2020 was conducted. Confounders of demography, dental features, skeletal parameters and LMCs were adjusted by multivariable linear regression to identify the association between BMI and LMCs. Group differences were evaluated with two-samples t-test and one-way ANOVA test. Mediation analysis was used for indirect effects assessment.

RESULTS

After adjusting for confounders, BMI is independently associated with upper lip length (0.039, [0.002-0.075]), soft pogonion thickness (0.120, [0.073-0.168]), inferior sulcus depth (0.040, [0.018-0.063]), lower lip length (0.208, [0.139-0.276]), and curve fitting revealed non-linearity to BMI in obese patients. Mediation analysis found BMI was associated with superior sulcus depth and basic upper lip thickness through upper lip length.

CONCLUSIONS

BMI is positively associated with LMCs, except for nasolabial angle as negatively, while obese patients reverse or weaken these associations.

Evaluation of facial soft-tissue values and craniofacial morphology in obese adolescent patients with different skeletal classes

Objectives:

The purpose of this study was to evaluate the facial soft tissue and craniofacial morphological structures in adolescent obese individuals with different skeletal patterns.

Materials and Methods:

The study was carried out on 292 adolescents examined under three groups based on their body mass indexes (BMIs) as obese, healthy, and overweight. The subjects were also categorized based on skeletal classes as Class I, Class II, and Class III.

Results:

The glabella, nasion, labiale inferius, labiomentale, and pogonion values of the female patients were significantly higher in obese group. In the obese and overweight groups, effective midfacial and mandibular length, anterior and posterior facial heights, and SN values of the females were higher than males. In the obese group, the mean effective midfacial and mandibular length (Co-A and Co-Gn), anterior and posterior facial heights (S-Go and N-Me), and anterior cranial base (SN) values were significantly higher than other groups.

Conclusion:

Soft-tissue thicknesses increase as BMI value increases. Craniofacial morphology reveals significant differences between BMI groups.

Facial soft tissue depth measurements in cone-beam computed tomography: A study of a Brazilian sample

Forensic facial reconstruction (approximation) (FFR) is an aid to human identification when no presumed identity is available. It is based on average soft tissue thickness (STT) applied onto a skull. These averages vary at each landmark according to sex, ancestry, and Facial Growth Patterns (FGP). To obtain the reference, there are different protocols and conditions, such as needles in cadavers, ultrasound, magnetic resonance, and computer tomography. Using cone-beam computed tomography (CBCT), landmark placement and direction of measurement are critical. The purpose of this article is to detailly describe a method for STT measurement in CBCT DICOM files and to test it in the analysis of a multi-ancestral Brazilian sample, subdivided into sex, age and FGP. A sample of 100 (50 male and 50 female) CBCT exams were selected and the volume was primarily been repositioned to cephalometric standards. A detailed description of the location and measurement direction of 32 landmarks was provided and granted good reproducibility of the measurements. The averages were assessed by sex, age, and FGP. There were significant differences between males and females. The CBCT measuring protocol provided standardization of measurements and is a method to be used in future researches. Advantages of CBCT, such as the subject's upright position and adjustable volume positioning, also justify its usage. Limited differences of STT were related to age and FGP. The updated Brazilian soft tissue thickness chart is a reliable source of data for forensic and clinical purposes.

Facial soft tissue thicknesses in craniofacial identification: Data collection protocols and associated measurement errors

Facial soft tissue thicknesses (FSTT) form a key component of craniofacial identification methods, but as for any data, embedded measurement errors are highly pertinent. These in part dictate the effective resolution of the measurements. As herein reviewed, measurement methods are highly varied in FSTT studies and associated measurement errors have generally not been paid much attention. Less than half (44%) of 95 FSTT studies comment on measurement error and not all of these provide specific quantification. Where informative error measurement protocols are employed (5% of studies), the mean error magnitudes range from 3% to 45% rTEM and are typically in the order of 10-20%. These values demonstrate that FSTT measurement errors are similar in size to (and likely larger than) the magnitudes of many biological effects being chased. As a result, the attribution of small millimeter or submillimeter differences in FSTT to biological variables must be undertaken with caution, especially where they have not been repeated across different studies/samples. To improve the integrity of FSTT studies and the reporting of FSTT measurement errors, we propose the following standard: (1) calculate the technical error of measurement (TEM or rTEM) in any FSTT research work; (2) assess the error embedded in the full data collection procedure; and (3) conduct validation testing of FSTT means proposed for point estimation prior to publication to ensure newly calculated FSTT means provide improvements. In order to facilitate the latter, a freely available R tool TDValidator that uses the C-Table data for validation testing is provided.