Quantitative 3D soft tissue analysis of symmetry prior to and after unilateral cleft lip repair compared with non-cleft persons (performed in Cambodia)

Frontiers in Three-Dimensional Surface Imaging Systems for 3D Face Acquisition in Craniofacial Research and Practice: An Updated Literature Review

Digitalizing all aspects of dental care is a contemporary approach to ensuring the best possible clinical outcomes. Ongoing advancements in 3D face acquisition have been driven by continuous research on craniofacial structures and treatment effects. An array of 3D surface-imaging systems are currently available for generating photorealistic 3D facial images. However, choosing a purpose-specific system is challenging for clinicians due to variations in accuracy, reliability, resolution, and portability. Therefore, this review aims to provide clinicians and researchers with an overview of currently used or potential 3D surface imaging technologies and systems for 3D face acquisition in craniofacial research and daily practice. Through a comprehensive literature search, 71 articles meeting the inclusion criteria were included in the qualitative analysis, investigating the hardware, software, and operational aspects of these systems. The review offers updated information on 3D surface imaging technologies and systems to guide clinicians in selecting an optimal 3D face acquisition system. While some of these systems have already been implemented in clinical settings, others hold promise. Furthermore, driven by technological advances, novel devices will become cost-effective and portable, and will also enable accurate quantitative assessments, rapid treatment simulations, and improved outcomes.

Longitudinal Three-Dimensional Stereophotogrammetric Growth Analysis in Infants with Unilateral Cleft Lip and Palate from 3 to 12 Months of Age

This longitudinal study aimed to evaluate facial growth and soft tissue changes in infants with complete unilateral cleft lip, alveolus, and palate (CUCLAP) at ages 3, 9, and 12 months. Using 3D images of 22 CUCLAP infants, average faces and distance maps for the entire face and specific regions were created. Color-coded maps highlighted more significant soft tissue changes from 3 to 9 months than from 9 to 12 months. The first interval showed substantial growth in the entire face, particularly in the forehead, eyes, lower lip, chin, and cheeks (p < 0.001), while the second interval exhibited no significant growth. This study provides insights into facial soft tissue growth in CUCLAP infants during critical developmental stages, emphasizing substantial improvements between 3 and 9 months, mainly in the chin, lower lip, and forehead. However, uneven growth occurred in the upper lip, philtrum, and nostrils throughout both intervals, with an overall decline in growth from 9 to 12 months. These findings underscore the dynamic nature of soft tissue growth in CUCLAP patients, highlighting the need to consider these patterns in treatment planning. Future research should explore the underlying factors and develop customized treatment interventions for enhanced facial aesthetics and function in this population.

Evaluation of Facial Esthetics Following NAM Versus CAD/NAM in Infants With Bilateral Cleft Lip and Palate: A Randomized Clinical Trial

OBJECTIVE

The aim is to compare the facial esthetics following nasoalveolar molding (NAM) versus computer-aided design NAM (CAD/NAM) in patients with bilateral cleft lip/palate (CLP).

DESIGN

The trial is a randomized comparative trial with a 1:1 allocation ratio.

PARTICIPANTS

Thirty infants with bilateral complete cleft lip and palate were recruited.

INTERVENTIONS

Patients were randomized between NAM and CAD/NAM groups. The treatment steps described by Grayson were followed for the NAM group. In the CAD/NAM group, digitized maxillary models were made to create a series of modified virtual models, which were used to fabricate the molding plates using 3-dimensional printing technology. The nasal stents were then added to the intraoral plates following the Grayson method. The study lasted for 4 months.

MAIN OUTCOMES

The assessment of the changes observed in the interlabial gap and nasolabial esthetics was done using standardized 2-dimensional photographs. The correlation between dental arch changes and extraoral facial esthetics was studied.

RESULTS

Both modalities showed improvement in nasolabial esthetics before the lip surgery. No statistically significant difference was found between NAM and CAD/NAM groups in any of the assessed variables.

CONCLUSIONS

Both interventions were effective in the management of infants with bilateral CLP.

Growth patterns of the nasolabial region following unilateral cleft lip primary repair

Surgical correction is the optimal way of repairing a congenital cleft lip. Patients with this condition often undergo initial surgical treatment at an early age and achieve an acceptable outcome. However, their levels of satisfaction will decrease in later stages of life as facial growth and development will inevitably cause changes in long-term outcomes, especially in the nasolabial region. Therefore, it is important for surgeons to understand nasolabial development after primary treatment and tailor their surgical techniques appropriately. This review focuses on the growth patterns of the nasolabial region after primary repair, so as to provide references for operative strategy.

Facial Asymmetry Detected with 3D Methods in Orthodontics: A Systematic Review

Background:

Historically, the development of two-dimensional (2D) imaging techniquesforerun that of three-dimensional (3D) ones. Some 2D methods are still considered valid and effective to diagnose facial asymmetry but 3D techniques may provide more precise and accurate measurements.

Objective:

The aim of this work is to analyze the accuracy and reliability of the imaging techniques available for the diagnosis of facial asymmetry in orthodontics and find the most reliable.

Methods:

A search strategy was implemented using PubMed (National Library of Medicine, NCBI).

Results:

A total of 3201 papers were identified in electronic searches. 90 articles, available in full text, were included in the qualitative synthesis consisting of 8 reviews on the diagnosis of facial asymmetry, 22 in vivo and in vitro studies on 2D methods and 60 in vivo and in vitro studies on 3D methods to quantify the asymmetry.

Conclusion:

2D techniques include X-ray techniques such as posterior-anterior cephalogram, which still represents the first level exam in the diagnosis of facial asymmetry. 3D techniques represent the second level exam in the diagnosis of facial asymmetry. The most current used techniques are CBCT, stereophotogrammetry, laser scanning, 3D optical sensors and contact digitization. The comparison between bilateral parameters (linear distances, angles, areas, volumes and contours) and the calculation of an asymmetry index represent the best choices for clinicians who use CBCT. The creation of a color-coded distance map seems to represent the most accurate, reliable and validated methods for clinicians who use stereophotogrammetry, laser scanning and 3D optical sensors.

A Normative Observational Study of the Relationship of the Philtral Ridges to the Columellar Base in South-Indian Population and its Significance on Cleft Lip Repair

Introduction The philtral ridges form a prominent visual landmark in the upper lip. An aesthetically pleasing cleft lip repair should restore this preferably without any scars cutting across it. Although there are several scientific publications on morphology of this structure and its variations, very few studies on the Indian population have been published.

Aim To study the morphology of the philtral ridges and their relationship to the columellar base in normal Indian children and its significance in cleft lip repair.

Methods 115 normal healthy children from southern India aged between one and 12 years were studied based on direct observation of the relationship of the superior end of the philtral ridge to the columellar base and nasal sill. In type A, the philtral ridge terminates at the nasal sill just lateral to the columellar base, and in type B, it either reaches or fades before reaching the columellar base. All observations were performed by the first author by examining standardized two-dimensional (2D) photographs of the upper lip-nose complex.

Results In this study, 74% of the subjects had the philtral column extending lateral to the columellar base.

Conclusion These finding assume a significance since, in a substantial proportion of the studied population, techniques of cleft lip repair such as the rotation advancement method, place a scar that crosses the upper third of the philtral ridge which may be undesirable.

Anthropometric Parameters of Nasomaxillary Complex in 2, 4, 6, and 12-Month-Old Children as a Reference for Cleft Lip and Palate Reconstructive Surgery

ABSTRACT

The purpose of this study was to analyze the morphology of the nasomaxillary complex of Iranian healthy infants of 2, 4, 6, and 12-month-old.In this cross-sectional study, 232 healthy Fars infants of 2, 4, 6, and 12-month-old referred to Mashhad health centers were evaluated. Photographic images were taken from the infants' frontal view at rest position. Anthropometric landmarks including width of the mouth, nose, columella, width and height of the philtrum, and height of the upper lip were measured by Photoshop software.The authors did not find any considerable differences in nasolabial morphology of Fars children between boys and girls, except for columellar width and the width of superior philtrum at all intervals. The mean columellar width decreased with increasing age in both sexes. The width of the lower philtrum decreased from 2 to 4 months in both sexes, but increased from 4 to 6 months. In girls, the mean height of the right and left philtrum and height of the upper lip increased by increasing age from 2 to 4 months. But it consistently reduced from 4 months to 6 and 12-month-old. In boys, the mean height of the right and left philtrum and height of the upper lip decreased from 2 to 4 months. It showed a mild increase from 4 to 6 months, and a relatively large reduction from 6 to 12 months.This study provides useful information for reconstructive surgeries of the nasolabial region in the population studied.

Characteristics of asymmetric cleft lip and palate surgical treatment

Relevance. The correct choice of the surgical technique for the treatment of the congenital asymmetric cleft lip and palate ensures the effectiveness of rehabilitation of patients with this pathology. The purpose is to present the results of the authors’ techniques for the surgical treatment of children with asymmetric cleft lip and/or palate.Materials and methods. Medical records of 687 children treated in 2015-2019 years were retrospectively analyzed at the clinic of maxillofacial surgery “Bonum” MСMC. The prevalence of asymmetric cleft lip and palate in children was determined. The prospective observation group included 84 patients with asymmetric cleft lip and/or palate. Clinical, anthropometric, statistical methods as well as patient photograph analysis and computer technologies were used during the research.Results. Prevalence of congenital asymmetric cleft lip and / or palate was determined (8.59%), classification and novel surgical techniques were offered and the results were evaluated.Conclusions. The prevalence of asymmetric cleft lip and palate is 86 per 1000 newborns with cleft lip and/ or palate. Scientific knowledge about the prevalence of asymmetric cleft lip and palate, as well as the systematization of this type of lesion in classifications, should be present in the practice of a maxillofacial surgeons and rehabilitation physicians who treat patients with this pathology. The proposed surgical techniques for the treatment of asymmetry in bilateral cleftlip and cleft palate provide positive results, excluding the need for further surgery. The reasonable choice of a surgical technique for the treatment of asymmetric cleft lip and palate is individual and may involve the use of additional nanomaterials. The authors’ techniques for the surgical treatment of asymmetric cleft lip and palate can be considered promising and aesthetically justified in view of good cosmetic results and full restoration of functions.

An Innovative Assessment of the Dynamics of Facial Movements in Surgically Managed Unilateral Cleft Lip and Palate Using 4D Imaging

OBJECTIVE

Assess facial asymmetry during maximum smile in patients with surgically managed unilateral cleft lip and palate (UCLP), using a dynamic 3-dimensional (3D) imaging (4-dimensional) system.

DESIGN

Prospective 2 cohort comparative study.

METHODS

Twenty-five surgically managed UCLP cases and 75 controls at 8 to 10 years of age were recruited. Facial movements during maximum smile were recorded using video stereophotogrammetry at a rate of 60 3D facial images per second. Maximum smile took approximately 3 seconds and generated 180 3D facial images for the analysis. A generic facial mesh which consists of more than 7000 quasi landmarks was used for the assessment of facial asymmetry at 5 key 3D frames representing the pattern of maximum smile.

RESULTS

Statistically significant differences were seen regarding the magnitude of facial asymmetry between the UCLP group and the noncleft controls. Higher average asymmetry in the UCLP group was seen in the 3D frame midway between maximum smile and rest (frame 4) followed by the frame at peak expression of maximum smile (frame 3). The average magnitude of nasolabial asymmetry of the control group was within 0.5 mm in comparison with the UCLP cases which was about 1.8 mm.

CONCLUSION

This study provided for the first time, an objective tool for analysis of the dynamics of muscle movements which provided an unprecedented insight into the anatomical basis of the residual dysmorphology. The research demonstrates the limitations of the primary lip repair in achieving symmetrical results and underpins the required refinements to improve the quality of surgical repair of cleft lip.

Influence of Unilateral Cleft Lip Configuration on Long-Term Facial Averageness: A New Three-Dimensional Analysis Approach

Background: Concepts regarding cleft lip and palate care vary widely globally, as there is no international consensus. Consequently, institutional surveillance of cleft concepts is essential. In addition to subjective expert rankings, three-dimensional (3D) photogrammetry of the face has become the gold standard for evaluation and objective assessment of facial structures. We evaluated cleft configuration preoperatively to determine the influence thereof on the long-term facial appearance/averageness of unilateral cleft lip patients. Methods: Plaster models of the patient's labio-oral region and nose were made preoperatively, digitized, and cleft configuration assessed (cleft width, cleft-columella angle, nasal projection, heminasal width ratio, transverse lip length, labial height). Between 4 and 12 years after surgery, stereophotogrammetry (3D face scans) were captured to determine the patients' individual facial averageness index (FAI) as a deviation from the population mean, using proportion indices (PIs) of facial landmarks and reference data provided by Farkas and FaceBase. Results: Cleft width (r = 0.77) and columella length correlated strongly with long-term facial averageness (r = 0.52). Decreasing FAI was seen with increasing patient age (r = -0.42), indicating increasing facial averageness. Other cleft properties showed weaker correlations. Cleft alveolus did not have any impact on FAI. Conclusions: The presented method allows objective measurement of facial appearance/averageness as well as preoperative cleft properties. It might be superior to subjective assessments of facial attractiveness/appearance. Objective cleft measurements are strong predictors for future facial averageness. Increasing averageness with growth and age suggests late corrective surgery.

[Secondary cheiloplasty in the treatment of cleft lip and palates]

In the course of treatment of cleft lip and palates, the quality of primary cheilo-rhinoplasty is essential to limit aesthetic and functional complications. This is why these primary reconstructions come under the domain of specialised centres with multidisciplinary teams. Unfortunately, residual imperfections often remain, especially in bilateral clefts, and secondary cheiloplasties represent for us a complex challenge. They aim at functional and aesthetic correction, and the choice of time is very random and depends largely on the psychological repercussions of the deformation in the child. It often occurs at the age of school entry and is combined with alveoloplasty. We then speak of alveolar transplantation with vestibulo and labio-plastie, the GPVP. Then we propose to combine all the resources of cosmetic surgery to improve the aesthetic and functional result of these children.

Facial and midfacial symmetry in cleft patients: Comparison to non-cleft children and influence of the primary treatment concept

PURPOSE

Patients with cleft lip, alveolus and palate (CLAP) may suffer from marked asymmetry with an impact on attractiveness and psychosocial aspects. The aim of this study was to assess symmetry in CLAP patients compared to non-cleft controls of similar age with regard to cleft type and treatment concept.

MATERIALS AND METHODS

In CLAP patients with different cleft forms and in healthy non-cleft subjects (control group) a three-dimensional stereophotogrammetric face scan was performed and an objective 3D asymmetry index (AI) was calculated for the whole face, the midface, the upper lip and the nose.

RESULTS

In total, 305 patients were included: 140 CLAP patients (90 male, 50 female, mean age 9.9 ± 3.6 years) and 165 controls (87 male, 78 female, mean age 8.7 ± 2.1 years). In general, CLAP patients showed significantly higher asymmetry than controls, with the most severe asymmetry found in unilateral complete CLAP. Patients treated according to an actual concept considering reconstruction of all affected muscular systems had a significant lower and more favourable AI than patients not treated according to this concept (p < 0.05).

CONCLUSION

An adequate treatment concept is essential to achieve better results concerning symmetry in CLAP, but symmetry values of healthy non-cleft controls are not reached.

Three-dimensional imaging methods to quantify soft and hard tissues change after cleft-related treatment during growth in patients with cleft lip and/or cleft palate: a systematic review

OBJECTIVES:

To assess the use of three-dimensional (3D) imaging methods to quantify the changes in soft- and hard-tissues in cleft patients after cleft-related treatment during growth.

METHODS:

PubMed, EMBASE, Web of Science and the Cochrane Library were searched up to 1 June 2018. Included publications were those using 3D imaging to quantify soft- and hard-tissue changes after cleft-related treatments in patients with any type of cleft, during growth. Data extraction and qualitative analysis were performed by two reviewers. The methodological quality of each study was reviewed using the QUADAS-2 tool.

RESULTS:

From 4 databases, 2315 articles were found. Full texts of 422 articles were analyzed and finally 12 articles were included for qualitative analysis. CT was performed in the majority of studies for hard-tissue quantification. Stereophotogrammetry, Laser scanner and 3D digitizer were identified as viable methods to quantify both soft- and hard-tissue changes, depending on whether the scan was made of the facial surface or the cast surface. Most studies conducted imaging analysis without registration between multitemporal images, which is the reason why they did not fulfil the inclusion criteria.

CONCLUSIONS:

Although several imaging modalities have the potential to quantify cleft-related treatment follow-up, there is an urgent need to assess the imaging methods and related analyses allowing to standardise a 3D imaging protocol to quantify hard- and soft-tissue treatment follow-up.

Quantifying Soft Tissue Changes in Cleft Lip and Palate Using Nonionizing Three-Dimensional Imaging: A Systematic Review

PURPOSE

The use of nonionizing 3-dimensional (3D) imaging in cleft lip and palate (CLP) research is well-established; however, general guidelines concerning the assessment of these images are lacking. The aim of the present study was to review the methods for quantification of soft tissue changes on 3D surface images acquired before and after an orthopedic or surgical intervention in CLP patients.

MATERIALS AND METHODS

A systematic literature search was performed using the databases MEDLINE (through PubMed), CENTRAL, Web of Science, and EMBASE. The literature search and eligibility assessment were performed by 2 independent reviewers in a nonblinded standardized manner. Only longitudinal studies reporting the assessment of pre- and postoperative 3D surface images and at least 10 CLP patients were considered eligible.

RESULTS

Fifteen unique studies (reported from 1996 to 2017) were identified after an eligibility assessment. The assessment of the 3D images was performed with landmark-dependent analyses, mostly supported by superimposition of the pre- and postoperative images. A wide spectrum of superimposition techniques has been reported. The reliability of these assessment methods was often not reported or was insufficiently reported.

CONCLUSIONS

Soft tissue changes subsequent to a surgical or an orthopedic intervention can be quantified on 3D surface images using assessment methods that are primarily based on landmark identification, whether or not followed by superimposition. Operator bias is inherently enclosed in landmark-dependent analyses. The reliability of these methods has been insufficiently reported.

Evaluation of a portable low-budget three-dimensional stereophotogrammetry system for nasal analysis

BACKGROUND

Three-dimensional (3D) photogrammetry has reached high standards and accuracy but is mainly conducted with stationary and expensive systems. The purpose of this study was to evaluate the accuracy of a low-budget portable system with special regard to the gracile and challenging nasal region.

MATERIAL AND METHODS

3D models of the perinasal area were acquired by impression-taking and the scanning of the generated plaster models (3Shape D500) or with a portable low-budget 3D stereophotogrammetry (FUEL3D^® SCANIFY^®) system. Four examiners analysed defined landmarks of the generated Standard Tessellation Language files with regard to accuracy and interobserver reliability by using 3dMDvultus™ software. A semi-automatic 3D best-fit analysis of both models was performed by using Geomagic^® and the Root Mean Squared (RMS) errors were calculated.

RESULTS

41 volunteers were included, with 22 perinasal and perioral landmarks, 15 3D distances and eight 3D angles being analysed per data set. In a point-based analysis the mean spreads were partially smaller in the plaster model scans. Most measurements showed very high (>0.8) to excellent (>0.9) intraclass correlation coefficients, the lowest being found for columella length (0.686) and left nostril width (0.636). Overall, the mean RMS error between the superimposed surfaces was 0.89 ± 0.22 mm in the best-fit analysis.

CONCLUSIONS

The corresponding software program was operator-friendly. The findings indicate that the analysed, affordable and portable system is a feasible solution for 3D image acquisition with comparable accuracy reported in the literature. Further studies will analyse the feasibility in neonates.

Assessment of regional asymmetry of the face before and after surgical correction of unilateral cleft lip

This study was carried out on 26 unilateral cleft lip and palate (UCLP) cases with mean age 3.6 ± 0.7 months.3D facial images were captured for each infant 2-3 days before the repair of cleft lip and at 4 months following surgery at a mean age of 8.2 ± 1.8 months, using a stereophotogrammetry imaging system. An iterative closest point (ICP) algorithm was used to superimpose the 3D facial model to its mirror image using VRMesh software. After the superimposition, the face model was divided into seven anatomical regions. Asymmetry of the entire face and of the anatomical regions was calculated by measuring the absolute distances between the 3D facial surface model and its mirror image. Colour maps were used to illustrate the patterns and magnitude of the facial asymmetry before and after surgery. There were significant decreases in the asymmetry scores for the nose, upper lip and the cheeks as a result of the surgical repair of cleft lips. Surgery did not change the magnitude of the asymmetry scores for the lower lip and chin. Residual nasolabial asymmetries were detected. The main outcome of the findings of this innovative study is to inform the required surgical refinement of primary repair of cleft lip in order to minimise facial asymmetry. We have presented a sensitive tool that could be used for comparative analysis of lip repair at various cleft centres and to guide secondary corrective surgery when required.

Correction of whistle deformity using autologous free fat grafting: first results of a pilot study and review of the literature

PURPOSE

Whistle deformities are frequent sequelae after surgical correction of cleft lip, trauma, or tumor excision. The aim of this study was to examine the role of autologous free fat grafting in the reconstruction of whistle deformity.

PATIENTS

Fifteen patients with whistle deformity were enrolled in this pilot study. The mean follow-up period was 19 months. Liposuction was done followed by the replantation of an average of 2.2 ml autologous fat per patient (range 0.7-4 ml). An overcorrection was performed in all patients.

RESULTS

All the patients showed improvements in whistle deformity. The mean resorption rate was 53% (range 30-80%). Three patients (20%) were not satisfied with the postoperative result. Six complications were assessed (4× feeling of pressure [27%], one hematoma [7%], one recurrent pain [7%]), but a major complication did not occur.

REVIEW

We also present a review of the literature with different techniques that were described in the last 20 years.

CONCLUSION

Autologous free fat graftings for reconstruction of whistle deformity represent a reliable method with a low complication rate. However, the resorption rate is unpredictable. If necessary, several autologous fat transplantations should be conducted at an interval of at least 6 months.

Novel computer vision analysis of nasal shape in children with unilateral cleft lip

BACKGROUND

Optimization of treatment of the unilateral cleft lip nasal deformity (uCLND) is hampered by lack of objective means to assess initial severity and changes produced by treatment and growth. The purpose of this study was to develop automated 3D image analysis specific to the uCLND; assess the correlation of these measures to esthetic appraisal; measure changes that occur with treatment and differences amongst cleft types.

METHODS

Dorsum Deviation, Tip-Alar Volume Ratio, Alar-Cheek Definition, and Columellar Angle were assessed using computer-vision techniques. Subjects included infants before and after primary cleft lip repair (N = 50) and children aged 8-10 years with previous cleft lip (N = 50). Two expert surgeons ranked subjects according to esthetic nose appearance.

RESULTS

Computer-based measurements strongly correlated with rankings of infants pre-repair (r = 0.8, 0.75, 0.41 and 0.54 for Dorsum Deviation, Tip-Alar Volume Ratio, Alar-Cheek Definition, and Columellar Angle, p < 0.01) while all measurements except Alar-Cheek Definition correlated moderately with rankings of older children post-repair (r ∼ 0.35, p < 0.01). Measurements were worse with greater severity of cleft type but improved following initial repair. Abnormal Dorsum Deviation and Columellar Angle persisted after surgery and were more severe with greater cleft type.

CONCLUSIONS

Four fully-automated measures were developed that are clinically relevant, agree with expert evaluations and can be followed through initial surgery and in older children. Computer vision analysis techniques can quantify the nasal deformity at different stages, offering efficient and standardized tools for large studies and data-driven conclusions.

Assessment of facial asymmetry before and after the surgical repair of cleft lip in unilateral cleft lip and palate cases

This study was performed to assess facial asymmetry in patients with unilateral cleft lip and palate (UCLP) before and after primary lip repair. Three-dimensional facial images of 30 UCLP cases (mean age 3.7±0.8months) captured 1-2days before surgery and 4 months after surgery using stereophotogrammetry were analysed. A generic mesh - a mathematical facial mask consisting of thousands of points (vertices) - was conformed on the three-dimensional images. Average preoperative and postoperative conformed facial meshes were obtained and mirrored by reflecting on the lateral plane. Facial asymmetry was assessed by measuring the distances between the corresponding vertices of the superimposed facial meshes. Asymmetries were further examined in three directions: horizontal, vertical, and anteroposterior. Preoperatively, the philtrum and bridge of the nose were deviated towards the non-cleft side. The maximum vertical asymmetry was at the upper lip. The greatest anteroposterior asymmetry was at the alar base and in the paranasal area. The overall facial asymmetry improved markedly after surgery. Residual anteroposterior asymmetry was noted at the alar base, upper lip, and cheek on the cleft slide. In conclusion, dense correspondence analysis provided an insight into the anatomical reasons for the residual dysmorphology following the surgical repair of cleft lip for future surgical consideration.

Surgical correction of upper lip deficit in patients with cleft lip using dermis fat graft

Background:

This study aimed to assess dermis fat graft (DFG) as a choice to correct the tissue deficit in the free border of the upper lip in cleft lip repair surgery.

Materials and Methods:

Thirty-five individuals who referred to Alzahra Hospital at 2013–2014, with lip deformity following the primary repair surgery of cleft lip underwent surgery by DFG technique. Outcomes were assessed 4 months after the surgery based on comparison of preoperative and postoperative photographs.

Results:

The results in 18 (51.42%) patients were excellent, 10 (28.57%) good, and 7 (20%) intermediate according to the satisfaction of patients and investigators in terms of filling of lip deficit and motion of the upper lip. Moreover, complications and pain were minimal after 4-month follow-up.

Conclusion:

This method introduces an admissible method with 80% good to excellent results based on satisfactory of patients and surgeon.

Digitalized analysis of philtral anatomy for planning individual treatment

OBJECTIVE

Restoration of the philtral region following traumatic, cleft, and tumor surgeries is often difficult due to influence of this feature to whole facial beauty. The aim of this study is to investigate the types and measurements of the philtrum and its relationship with the upper lip using a software.

METHODS

Standard personal photographs of the philtral region were obtained from 200 young adults participated in this study. Linear analyses (the lengths of philtral column and dimple; the philtral width) and angular analyses (apex and central angles of Cupid's bow) were measured as reference points. As for the shape of the philtral column, it was categorized as four distinct types: parallel, triangular, concave, and unclear type.

RESULTS

The philtral width was 11.37 ± 1.9 mm in males, 10.21 ± 1.80 mm in females. The length of the philtral dimple was 18.16 ± 3.6 mm in males, 18.16 ± 3.6 mm in females. Compared with women, both of the measured average philtral reference lengths displayed a significantly greater value in men. In the meanwhile, compared to women, the angular measurements of Cupid's bow (i.e., the apex and central angle of Cupid's bow) were smaller in men. It was 127.47 ± 12.74° mm in males, 134.1 ± 11.38° mm in females. The triangular and concave types were associated with a substantial fraction in men, whereas the triangular and parallel types were predominant in women. There were significant gender differences in the esthetic rankings of philtral column shapes.

CONCLUSIONS

These results suggest digitalized reference values relative to the philtral column which may increase the success of the individual reconstructive treatment of the surgical procedures and reduce possible asymmetrical appearance. With the help of certain software, this research has made possible to investigate the ideal parameters of philtral construction in defining the best surgical solution for the patient.

A novel computer system for the evaluation of nasolabial morphology, symmetry and aesthetics after cleft lip and palate treatment. Part 1: General concept and validation

PURPOSE

The need for a widely accepted method suitable for a multicentre quantitative evaluation of facial aesthetics after surgical treatment of cleft lip and palate (CLP) has been emphasized for years. The aim of this study was to validate a novel computer system 'Analyse It Doc' (A.I.D.) as a tool for objective anthropometric analysis of the nasolabial region.

MATERIALS AND METHODS

An indirect anthropometric analysis of facial photographs was conducted with the A.I.D. system and Adobe Photoshop/ImageJ software. Intra-rater and inter-rater reliability and the time required for the analysis were estimated separately for each method and compared.

RESULTS

Analysis with A.I.D. system was nearly 10-fold faster than that with the reference evaluation method. The A.I.D. system provided strong inter-rater and intra-rater correlations for linear, angular and area measurements of the nasolabial region, as well as a significantly higher accuracy and reproducibility of angular measurements in submental view. No statistically significant inter-method differences were found for other measurements.

CONCLUSIONS

The hereby presented novel computer system is suitable for simple, time-efficient and reliable multicenter photogrammetric analyses of the nasolabial region in CLP patients and healthy subjects.

A novel computer system for the evaluation of nasolabial morphology, symmetry and aesthetics after cleft lip and palate treatment. Part 2: Comparative anthropometric analysis of patients with repaired unilateral complete cleft lip and palate and healthy individuals

PURPOSE

The aim of this study was to use a novel system, 'Analyse It Doc' (A.I.D.) for a complex anthropometric analysis of the nasolabial region in patients with repaired unilateral complete cleft lip and palate and in healthy individuals.

MATERIALS AND METHODS

A set of standardized facial photographs in frontal, lateral and submental view have been taken in 50 non-cleft controls (mean age 20.6 years) and 42 patients with repaired unilateral complete cleft and palate (mean age 19.57 years). Then, based on linear, angular and area measurements taken from the digital photographs with the aid of the A.I.D. system, a photogrammetric analysis of intergroup differences in nasolabial morphology and symmetry was conducted.

RESULTS

Patients with cleft lip and palate differed from the controls in terms of more than half of analysed angular measurements and proportion indices derived from linear and area measurements of the nasolabial region.

CONCLUSIONS

The findings presented herein imply that despite primary surgical repair, patients with unilateral complete cleft lip and palate still show some degree of nasolabial dysmorphology. Furthermore, the study demonstrated that the novel computer system is suitable for a reliable, simple and time-efficient anthropometric analysis in a clinical setting.

Measuring Symmetry in Children With Cleft Lip. Part 3: Quantifying Nasal Symmetry and Nasal Normalcy Before and After Unilateral Cleft Lip Repair

OBJECTIVE

The purpose of this project was to develop objective computer-based methods to measure nasal asymmetry and abnormality in children undergoing treatment of unilateral cleft lip (UCL) and to determine the correlation of these measures to clinical expectations.

PARTICIPANTS

Thirty infants with UCL undergoing cleft lip repair; 27 children with UCL aged 8 to 10 years who had previously undergone cleft lip repair; 3 control infants; 3 control children aged 8 to 10 years.

INTERVENTIONS

To measure nasal symmetry, we used a process of depth mapping and calculated the Depth Area Difference. To measure abnormality, we used the reconstruction error from Principle Component Analysis (PCA) that was based upon characteristics of a dataset of over 2000 images of normal control subjects.

MAIN OUTCOME MEASURES

Depth Area Difference and PCA Reconstruction Error for cleft type, changes with surgery, and individual subjects ranked according to cleft severity were assessed.

RESULTS

Significant differences in Depth Area Difference and PCA Reconstruction Error were found between cleft types and found before and after surgery. Nasal symmetry and normalcy scores for infants with UCL approached those of controls after surgery, and there was a strong correlation with ranked cleft severity. For older children, measures of nasal symmetry and abnormality were better than infants prior to repair but worse than infants following UCL repair.

CONCLUSIONS

Our computer-based 3D analysis of nasal symmetry and normalcy correlated with clinical expectations. Automated processing made measurement convenient. Use of these measures may help to objectively measure cleft severity and treatment outcome.

Measuring Symmetry in Children With Unrepaired Cleft Lip: Defining a Standard for the Three-Dimensional Midfacial Reference Plane

OBJECTIVE

Quantitative measures of facial form to evaluate treatment outcomes for cleft lip (CL) are currently limited. Computer-based analysis of three-dimensional (3D) images provides an opportunity for efficient and objective analysis. The purpose of this study was to define a computer-based standard of identifying the 3D midfacial reference plane of the face in children with unrepaired cleft lip for measurement of facial symmetry.

PARTICIPANTS

The 3D images of 50 subjects (35 with unilateral CL, 10 with bilateral CL, five controls) were included in this study.

INTERVENTIONS

Five methods of defining a midfacial plane were applied to each image, including two human-based (Direct Placement, Manual Landmark) and three computer-based (Mirror, Deformation, Learning) methods.

MAIN OUTCOME MEASURE

Six blinded raters (three cleft surgeons, two craniofacial pediatricians, and one craniofacial researcher) independently ranked and rated the accuracy of the defined planes.

RESULTS

Among computer-based methods, the Deformation method performed significantly better than the others. Although human-based methods performed best, there was no significant difference compared with the Deformation method. The average correlation coefficient among raters was .4; however, it was .7 and .9 when the angular difference between planes was greater than 6° and 8°, respectively.

CONCLUSIONS

Raters can agree on the 3D midfacial reference plane in children with unrepaired CL using digital surface mesh. The Deformation method performed best among computer-based methods evaluated and can be considered a useful tool to carry out automated measurements of facial symmetry in children with unrepaired cleft lip.

Measuring Symmetry in Children With Cleft Lip. Part 2: Quantification of Nasolabial Symmetry Before and After Cleft Lip Repair

OBJECTIVE

The first part of this study validated an automated computer-based method of identifying the three-dimensional midfacial plane in children with unrepaired cleft lip. The purpose of this second part is to develop computer-based methods to quantify symmetry and to determine the correlation of these measures to clinical expectations.

PARTICIPANTS

A total of 35 infants with unrepaired unilateral cleft lip and 14 infant controls.

INTERVENTIONS

Six computer-based methods of quantifying symmetry were developed and applied to the three-dimensional images of infants with unilateral cleft lip before and after cleft lip repair and to those of controls.

MAIN OUTCOME MEASURE

Symmetry scores for cleft type, changes with surgery, and individual subjects ranked according to cleft severity were assessed.

RESULTS

Significant differences in symmetry scores were found between cleft types and found before and after surgery. Symmetry scores for infants with unilateral cleft lip approached those of controls after surgery, and there was a strong correlation with ranked cleft severity.

CONCLUSIONS

Our computer-based three-dimensional analysis of nasolabial symmetry correlated with clinical expectations. Automated processing made measurement convenient. Use of these measures may help to objectively measure cleft severity and treatment outcome.

Difference in nasolabial features between awake and asleep infants with unilateral cleft lip: Anthropometric measurements using three-dimensional stereophotogrammetry

PURPOSE

Cleft lip repair is performed in the supine position, tilting the head back under general anesthesia. However, postoperative results are evaluated in the upright position while patients are awake. The purpose of this study was to anthropometrically assess whether nasolabial features of infants with unilateral cleft lip are influenced by posture and anesthesia.

MATERIAL AND METHODS

Three-dimensional facial images in a preoperative upright position and operating supine position under general anesthesia were captured from 51 consecutive infants with unilateral cleft lip. Twenty-four indirect anthropometric measurements (11 for the nose and 13 for the lip elements) were considered on each infant.

RESULTS

In the supine position under general anesthesia, alar surface distance was significantly shorter (p < 0.001). Regarding lip measurements, medial lip height of the cleft side and philtrum height were significantly smaller (p < 0.05 and p < 0.05, respectively), whereas vermilion height was greater (p < 0.01). In addition, the cleft width and lip width were significantly broader (p < 0.001 and p < 0.001, respectively) after general anesthesia.

CONCLUSIONS

Several nasolabial alteration patterns are found after general anesthesia that are presumably attributable to cessation of nasal breathing and the action of muscle relaxation. Surgeons should take these nasolabial changes into account during preoperative planning and postoperative assessment.

Dependence of columella development on the technique used for primary cleft lip closure

OBJECTIVE

Primary cleft lip closure can be achieved by use of different types of surgery. The procedures of Millard, Veau, and Delaire are among the techniques most frequently performed worldwide. The factors which affect development of the columella have not been studied, however.

SETTING

University Hospital of Leipzig, Germany, Department of Oral, Craniomaxillofacial and Facial Plastic Surgery.

PATIENTS, PARTICIPANTS

In a comparative, retrospective, non-randomised study, we obtained anthropometric details from photographs of 120 unilateral and bilateral cleft patients after cleft lip closure by use of the techniques of Millard or Veau (n = 60) and Delaire (n = 60). Length and shape of the columella was assessed twice-first at the age of 10 months and again at the age of 10 years. Anthropometric characteristics of columella morphology and development were compared between the two groups.

RESULTS

At the age of 10 months, the ratio of nasal height to width (interalar distance) was significantly different for unilateral and bilateral cases, and results were better for the Delaire groups (p = 0.001 unilateral and p > 0.001 bilateral). This effect was no longer apparent at 10-year follow up. Another index which tended to indicate better results in the Delaire groups was the nasal width index. In the summary of the anthropometric values investigated, however, differences between the Millard or Veau group and the Delaire group were marginal.

CONCLUSION

Cleft lip closure by the technique of Millard for unilateral cleft lips and of Veau for bilateral cases is neither better nor worse than Delaire cheiloplasty for unilateral and bilateral clefts.

A Pilot Study on the Influence of Facial Expression on Measurements in Three-Dimensional Digital Surfaces of the Face in Infants With Cleft Lip and Palate

OBJECTIVE

Three-dimensional surface imaging is an increasingly popular modality for face measurements in infants with cleft lip and palate. Infants are noncompliant toward producing specific facial expressions, and selecting the appropriate moment of acquisition is challenging. The objective was to estimate amount and spatial distribution of deformation of the face due to facial expression in infants with cleft lip and palate and provide recommendations for an improved acquisition protocol, including a method of quality control in terms of obtaining images with true neutral expression.

MATERIAL AND METHODS

Three-dimensional surface images of ten 4-month-old infants with unrepaired cleft lip and palate were obtained using a 3dMDface stereophotogrammetric system. For each subject, five surface images judged as representing a neutral expression were obtained during the same photo session. Mean and maximum deformations were calculated. A formalized review was performed, allowing the image exhibiting the "best" neutral expression to be selected, thus decreasing errors due to residual facial expression.

RESULTS

Deformation due to facial expression generally increased from forehead to chin. The amount of deformation in three selected regions were determined: nose (mean, 1 mm; maximum = 3 mm); cleft region (mean, 2 mm; maximum = 5 mm); chin region (mean, 5 mm; maximum = 12 mm). Analysis indicated that introduction of a formalized review of images could reduce these errors by a factor of 2.

CONCLUSIONS

The continuous change of facial expression in infants represents a substantial source of error; however, this may be reduced by incorporating a formalized review into the acquisition protocol.

Influence of maxillary obturator prostheses on facial morphology in patients with unilateral maxillary defects

STATEMENT OF PROBLEM

Facial asymmetry is prominent with individuals with unilateral bone resorption and can lead to decreased quality of life.

PURPOSE

The purpose of this study was to investigate the influence of maxillary obturator prostheses on facial morphology of individuals with unilateral maxillary defects by using 3-dimensional digital stereophotogrammetry.

MATERIAL AND METHODS

The facial data of 8 participants with unilateral maxillary defects were acquired with a noncontact 3-dimensional digitizer, both with and without maxillary prostheses. The mid-facial plane was established by overlapping an original facial image with its mirror image. Displacement at 18 measurement points, including 7 bilateral pairs, was compared between the 2 sides, with and without the prostheses. Asymmetry indices of these 7 pairs also were calculated. Multivariate repeated-measures ANOVA was used to determine differences.

RESULTS

Displacements of the lateral and inferior points at the ala of the nose were significantly greater on the defect side than on the normal side. The distances between the ideal and defect side points at the superior ala, the upper lip, and the angle of the mouth decreased significantly with the prosthesis. No significant differences were found in asymmetry indices, but the angle of the upper lip line to the mid-sagittal plane increased significantly with the prosthesis.

CONCLUSIONS

The 3-dimensional analyzing method developed in this study can be useful in evaluating facial reconstruction with maxillary obturator prostheses with individuals with unilateral maxillary defects. The prostheses affect the region of the nasal ala, the upper lip, and the angles of the mouth.

Reliability of nasolabial anthropometric measures using three-dimensional stereophotogrammetry in infants with unrepaired unilateral cleft lip

BACKGROUND

Surgical and orthodontic treatment of unilateral cleft lip +/- palate can produce dramatic changes in nasolabial form; however, the lack of ideal methods with which to objectively document three-dimensional form limits the ability to assess treatment outcomes. The purpose of this study was to determine the reliability of three-dimensional stereophotogrammetry for anthropometric assessment of the unilateral cleft lip +/- palate deformity in infants before cleft lip repair.

METHODS

Preoperative three-dimensional images were acquired from 26 consecutive patients with unrepaired unilateral cleft lip +/- palate. Three raters performed indirect anthropometry on each image on two separate occasions, with at least 1 week between rating sessions. One rater performed direct measurements on participants before surgery while in the operating room. Twenty-six linear and angular measurements were considered, and intrarater, interrater, and intermethod reliability were assessed.

RESULTS

Regarding intrarater and interrater reliability, most measurements had Pearson coefficients greater than 0.75, mean differences less than 0.8 mm, and mean proportional differences less than 0.1. For measurements involving vermilion height, nostril remnants, or Cupid's bow width, Pearson coefficients ranged from 0.3 to 0.75, mean differences ranged from 0.4 to 0.9 mm, and mean proportional differences ranged from 0.1 to 0.3. Regarding intermethod reliability, correlation coefficients ranged from 0.4 to 0.75 for most measurements. The mean differences for nose and lip measurements were less than 1 mm and between 0.8 and 1.3 mm, respectively.

CONCLUSION

Three-dimensional stereophotogrammetry provides a reliable method for many anthropometric measurements of nasolabial form in infants with unrepaired unilateral cleft lip +/- palate.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, II.

Three-dimensional imaging methods for quantitative analysis of facial soft tissues and skeletal morphology in patients with orofacial clefts: a systematic review

Background

Current guidelines for evaluating cleft palate treatments are mostly based on two-dimensional (2D) evaluation, but three-dimensional (3D) imaging methods to assess treatment outcome are steadily rising.

Objective

To identify 3D imaging methods for quantitative assessment of soft tissue and skeletal morphology in patients with cleft lip and palate.

Data sources

Literature was searched using PubMed (1948–2012), EMBASE (1980–2012), Scopus (2004–2012), Web of Science (1945–2012), and the Cochrane Library. The last search was performed September 30, 2012. Reference lists were hand searched for potentially eligible studies. There was no language restriction.

Study selection

We included publications using 3D imaging techniques to assess facial soft tissue or skeletal morphology in patients older than 5 years with a cleft lip with/or without cleft palate. We reviewed studies involving the facial region when at least 10 subjects in the sample size had at least one cleft type. Only primary publications were included.

Data extraction

Independent extraction of data and quality assessments were performed by two observers.

Results

Five hundred full text publications were retrieved, 144 met the inclusion criteria, with 63 high quality studies. There were differences in study designs, topics studied, patient characteristics, and success measurements; therefore, only a systematic review could be conducted. Main 3D-techniques that are used in cleft lip and palate patients are CT, CBCT, MRI, stereophotogrammetry, and laser surface scanning. These techniques are mainly used for soft tissue analysis, evaluation of bone grafting, and changes in the craniofacial skeleton. Digital dental casts are used to evaluate treatment and changes over time.

Conclusion

Available evidence implies that 3D imaging methods can be used for documentation of CLP patients. No data are available yet showing that 3D methods are more informative than conventional 2D methods. Further research is warranted to elucidate it.

Systematic review registration

International Prospective Register of Systematic Reviews, PROSPERO CRD42012002041

Nostril Morphometry Evaluation before and after Cleft Lip Surgical Correction: Clinical Evidence

Introduction The purpose to this work is to review systematically the morphological changes of the nostrils of patients undergoing surgery for correction of cleft lip and identify in the literature the issues involved in the evaluation of surgical results in this population.

Review of Literature A review was conducted, searching for clinical evidence from MEDLINE. The search occurred in January 2012. Selection criteria included original articles and research articles on individual subjects with cleft lip or cleft palate with unilateral nostril anthropometric measurements before and after surgical correction of cleft lip and measurements of soft tissues. There were 1,343 articles from the search descriptors and free terms. Of these, five articles were selected.

Discussion Most studies in this review evaluated children in Eastern countries, using different measurement techniques but with the aid of computers, and showed improved nostril asymmetry postoperatively compared with preoperatively.

Conclusion There is a reduction of the total nasal width postoperatively compared with preoperative measurements in patients with cleft lip.

Three-dimensional facial distances of Northern Sudanese persons from childhood to young adulthood

No current age- and gender-related normative data exist for the dimensions of facial structures in Northern Sudanese subjects. In the current study information about normal sex- and age-related linear distances is provided. The three-dimensional coordinates of 14 landmarks on the facial soft tissues were obtained using a hand-held laser scanner in 653 healthy Northern Sudanese subjects (326 males and 327 females) aged 4-30 years. From the landmarks, 13 linear distances were calculated, and averaged for age and sex. Comparisons were performed by factorial analysis of variance. All analyzed linear soft tissue facial dimensions were significantly larger in men than in women (p < 0.01), except mouth width (ch-ch), upper facial height (n-sn), mandibular body length (pg-go) and width (go-go). All measurements underwent significant modifications as a function of age (p < 0.01), with significant age × sex interactions (p < 0.01) for all linear dimensions except lower face height (sn-pg). Overall, when compared to literature data for African and Caucasoid subjects, several differences were found, pointing to the necessity of ethnic-specific data. Data collected in the present investigation could serve as a database for the quantitative description of human facial morphology during normal growth and development.

Frontal soft tissue analysis using a 3 dimensional camera following two-jaw rotational orthognathic surgery in skeletal class III patients

Although two dimensional cephalometry is the standard method for analyzing the results of orthognathic surgery, it has potential limits in frontal soft tissue analysis. We have utilized a 3 dimensional camera to examine changes in soft tissue landmarks in patients with skeletal class III dentofacial deformity who underwent two-jaw rotational setback surgery. We assessed 25 consecutive Asian patients (mean age, 22 years; range, 17-32 years) with skeletal class III dentofacial deformities who underwent two-jaw rotational surgery without maxillary advancement. Using a 3D camera, we analyzed changes in facial proportions, including vertical and horizontal dimensions, facial surface areas, nose profile, lip contour, and soft tissue cheek convexity, as well as landmarks related to facial symmetry. The average mandibular setback was 10.7 mm (range: 5-17 mm). The average SNA changed from 77.4° to 77.8°, the average SNB from 89.2° to 81.1°, and the average occlusal plane from 8.7° to 11.4°. The mid third vertical dimension changed from 58.8 mm to 57.8 mm (p = 0.059), and the lower third vertical dimension changed from 70.4 mm to 68.2 mm (p = 0.0006). The average bigonial width decreased from 113.5 mm to 109.2 mm (p = 0.0028), the alar width increased from 34.7 mm to 36.1 mm (p-value = 0.0002), and lip length was unchanged. Mean mid and lower facial surface areas decreased significantly, from 171.8 cm(2) to 166.2 cm(2) (p = 0.026) and from 71.23 cm(2) to 61.9 cm(2) (p < 0.0001), respectively. Cheek convexity increased significantly, from 171.8° to 155.9° (p = 0.0007). The 3D camera was effective in frontal soft tissue analysis for orthognathic surgery, and enabled quantitative analysis of changes in frontal soft tissue landmarks and facial proportions that were not possible with conventional 2D cephalometric analysis.

Morphometry of the soft tissues of the orbital region in Northern Sudanese persons

The orbital region plays a predominant role in the evaluation of the craniofacial complex. No current normative data exist for Northern Sudanese subjects. In the current study information about normal sex- and age-related dimensions of the orbital region was provided. The three-dimensional coordinates of ten landmarks on the orbital soft tissues were obtained using a hand-held laser scanner in 654 healthy Northern Sudanese subjects aged 4-30 years. From the landmarks, biocular and intercanthal widths, paired height and inclination of the orbit relative to both the true horizontal (head in natural head position) and Frankfurt plane, length and inclination of the eye fissure, the relevant ratios, were calculated, and averaged for age and sex. Comparisons were performed by factorial analysis of variance. All analysed linear soft-tissue orbital dimensions, except intercanthal width and left orbital height, were significantly larger in men than in women (p<0.01). A significant sexual dimorphism was found also for the height-to-width ratios (larger in women in most age groups), the orbital inclinations vs. the true horizontal and Frankfurt plane (both measurements were almost always larger in men than in women), and the right side inclination of the eye fissure vs. the true horizontal (larger in women than in men), while no sex-related differences were observed for the left side inclination of the eye fissure vs. the true horizontal. All measurements but the right side inclination of the eye fissure vs. the true horizontal underwent significant modifications as a function of age, with several significant age×sex interactions. Biocular and intercanthal widths, orbital height, length of the eye fissure, all increased from childhood to young adulthood; in the second decade of life all age-related increments were larger in men than in women. Overall, when compared to literature data for African and Caucasoid subjects, several differences were found, pointing to the necessity of ethnic-specific data. Data collected in the present investigation could serve as a database for the quantitative description of human orbital morphology during normal growth and development. Forensic applications (evaluations of traumas, craniofacial alterations, teratogenic-induced conditions, facial reconstruction, ageing of living and dead people, personal identification) may also benefit from age- and sex-based data banks.

Three-dimensional vector analysis of mandibular structural asymmetry

OBJECTIVES

The three-dimensional (3D) asymmetric structure of the mandible makes it necessary to analyze both its size and angle. Currently the developing 3D analysis techniques are not able to perform the simultaneous linear and angular measurements. Our aim was to evaluate mandibular asymmetry using a vector-based system by constructing 3D vectors for the mandibular functional units.

MATERIAL AND METHODS

We analyzed the 3D computed tomography images of normal control (N = 27) and asymmetric mandibles (N = 40). We created 3D vectors for the condylar, coronoid, body, gonial, and symphyseal functional units and compared the corresponding pairs of 3D vectors by calculating vector operations.

RESULTS

The vector difference and other vector components represented the individual 3D architectural pattern and severity of the asymmetric mandible. The body unit contributed most to mandibular asymmetry followed by the condylar unit.

CONCLUSIONS

The results indicate that 3D vector analysis can improve our understanding of the 3D architecture of asymmetric mandibles. This type of 3D vector analysis can be a useful tool for the comprehensive evaluation of its asymmetric mandibular structure.