Comparison of microparticle transport and deposition in nasal cavity of three different age groups.

Objective: The nasal cavity effectively captures the particles present in inhaled air, thereby preventing harmful and toxic pollutants from reaching the lungs. This filtering ability of the nasal cavity can be effectively utilized for targeted nasal drug delivery applications. This study aims to understand the particle deposition patterns in three age groups: neonate, infant, and adult.Materials and methods: The CT scans are built using MIMICS 21.0, followed by CATIA V6 to generate a patient-specific airway model. Fluid flow is simulated using ANSYS FLUENT 2021 R2. Spherical monodisperse microparticles ranging from 2 to 60 µm and a density of 1100 kg/m3 are simulated at steady-state and sedentary inspiration conditions.Results: The highest nasal valve depositions for the neonate are 25% for 20 µm, for infants, 10% for 50 µm, 15% for adults, and 15% for 15 µm. At mid nasal region, deposition of 15% for 20 µm is observed for infant and 8% for neonate and adult nasal cavities at a particle size of 10 and 20 µm, respectively. The highest particle deposition at the olfactory region is about 2.7% for the adult nasal cavity for 20 µm, and it is <1% for neonate and infant nasal cavities.Discussion and conclusions: The study of preferred nasal depositions during natural sedentary breathing conditions is utilized to determine the size that allows medication particles to be targeted to specific nose regions.

Establishment and verification of a method for analyzing nasal blackheads images.

BACKGROUND: As people pay more attention to their skin health and the demand of developing skin care products for facial blackheads grows, the value of objective and efficient image recognition methods for blackheads is becoming more evident. Inspired by this current situation, this study attempted to analyze the number of blackheads of different severity automatically on the nose using an object recognition method on photographs of the nasal blackheads of subjects. METHOD: This study collected 350 subjects' facial photos in the laboratory environment, who aged 18-60, with blackhead symptoms in the nasal region. And expert assessment was used as a reference for machine learning to verify the performance of the nasal blackhead image recognition model through consistency and correlation analysis. RESULTS: The study concluded that the algorithm accuracy reached above 0.9, the model itself was effective, and the consistency between the model and the expert assessor assessment results was good, with the number of nasal blackheads, the count of blackheads of different severity, and the intra-group correlation coefficient ICC of blackhead severity all above 0.9, indicating that the deep learning-based assessment model had high overall performance and the evaluation results were comparable to those of the expert assessor. CONCLUSION: The recognition and analyzing model of nasal blackhead images provides a scientifically objective and accurate method for identifying the number and evaluating the severity of nasal blackheads. By using this model, the efficiency of evaluating nasal blackhead images in the cosmetics clinical trial will be improved. The assessment result of nasal blackheads will be objective and stable, and not only rely on the professional knowledge and clinical experience of assessors. The model can try to be applied in cosmetics efficacy testing and continuously optimized.

Measurement of Nasal Skin Thickness and Body Mass Index in Preoperative Rhinoplasty Patients Utilizing Computed Tomography Scanning and Ultrasound Techniques: A Prospective Comparative Study.

One of the most important indicators of rhinoplasty success is nasal skin thickness. Nasal thickness can lead to irregularities over the osseocartilaginous framework among patients with thin nasal skin and difficulty making tip work changes in patients with thick nasal skin. This study aimed to compare different objective methods. These include computed tomography (CT) and ultrasound (US) techniques, and report the relationship between nasal skin thickness and body mass index (BMI). A prospective cross-sectional study that included all patients at the rhinoplasty clinic (King Abdul-Aziz University Hospital), Riyadh, Saudi Arabia, between December 2022 and March 2023. Age, sex, and Fitzpatrick skin type were collected from the patients' histories and physical examinations. Body mass index was calculated for the subjects. The study sample included 29 patients. The median age of the patients was 25 years (interquartile range: 20-32 y). Most of the included patients were Saudi (89.7%, n = 26). Females represented 62.1% of the study sample. The average BMI was 25.6 ± 4.95 kg/m 2 . The highest correlation was observed between the US and CT tip ( r = 0.544, P < 0.01) and rhinion ( r = 0.525, P < 0.01) measurements. Body mass index was not associated with any US or CT measurements when BMI was used as a continuous or ordinal variable. The correlation between the US and CT measurements was highest for rhinoin and tip measurements, whereas supratip measurements were not correlated ( r = -0.029, P = 0.88). The correlation between mid-dorsum and nasion measurements was low (~0.3). The correlation between nasal skin thickness using CT and US varies depending on the nasal point and location. Body mass index was not associated with nasal skin thickness.

Correlating Jaw Bone Growth and Nasal Morphology Among Adult Patients With Cleft Lip and Palate: A Retrospective Cephalometric Study.

This retrospective cross-sectional study reviewed adult patients with operated cleft lip and/or palate (CL/P) and normal control, and performed comprehensive craniofacial and nasal morphological analyses based on lateral cephalometric radiographs. Pearson or Spearman correlation coefficient assessed intraclass correlation. Seven hundred fifty-seven operated patients with CL/P, and 165 noncleft normal controls were enrolled. Among the normal and CL/P groups, S-N-A angle registered positive correlations with nasal base prominence (S-N'-Sn, degrees). Upper facial height (N-ANS, mm) had positive correlations with nasal dorsum length (N'-Prn, mm) and nasal bone length (N-Na, mm). Although in patients with bilateral cleft lip and palate, there were moderate negative correlations ( r =-0.541, P <0.05) with soft tissue facial profile angle (FH-N'Pog', degree) and nasolabial angle (Cm-Sn-ULA, degree). Correlation exists between the morphology of jaw bones and external nose among patients with CL/P. Maxillary sagittal insufficiency is associated with concave nasal profile, and maxilla height is associated with nasal length.

Determination of Mouth Width for Facial Reconstruction Based on Statistical Regression Model.

INTRODUCTION: It is important to generate predictable statistical models by increasing the number of variables on the human skeletal and soft tissue structures on the face to increase the accuracy of human facial reconstructions. The purpose of this study was to determine mouth width 3-dimensionally based on statistical regression model. MATERIAL AND METHODS: Cone-beam computed tomography scan data from 130 individuals were used to measure the horizontal and vertical dimensions of orbital and nasal structures and intercanine width. The correlation between these hard tissue variables and the mouth width was evaluated using the statistical regression model. RESULTS: Orbital width, nasal width, and intercanine width were found to be strong predictors of the mouth width determination and were used to generate the regression formulae to find the most approximate position of the mouth. CONCLUSION: These specific variables may contribute to improving the accuracy of mouth width determination for oral and maxillofacial reconstructions.

Three-dimensional nasal asymmetry analysis between adolescence and adulthood in postoperative patients with unilateral cleft lip and palate using computed tomography.

AIM: To investigate the differences of the nasal soft and hard tissue asymmetry in postoperative patients with unilateral cleft lip and palate (UCLP) between adolescence and adulthood, and to explore the correlation of nasal soft and hard tissue asymmetry. METHODS: CT data from 47 repaired UCLP patients were included and divided into two groups:1. adolescent group: 23 patients (15 males, 8 females; age: 10-12 years old). 2. adult group: 24 patients (16 males, 8 females; age:18-32 years old). The three-dimensional asymmetry in nasal soft and hard tissues was analyzed. Additionally, the correlation between nasal soft and hard tissue asymmetry was also analyzed. RESULTS: Both the adolescent group and adult group showed asymmetries in nasal soft and hard tissues. Compared to the adolescent group, the adult group had a significantly increased horizontal asymmetry of nasal soft tissues Sbal (P < 0.05). Furthermore, the sagittal asymmetry of soft tissue Glat (P < 0.05), Sbal (P < 0.001), Sni (P < 0.001) and hard tissue LPA (P < 0.05) also increased significantly. In the adult group, there were more landmarks with a correlation between the asymmetry of nasal hard tissue and soft tissue compared to the adolescent group. There were moderate to strong correlations between nasal hard and soft tissue symmetries in the horizontal and sagittal directions (0.444 < r < 764), but no correlation in the vertical direction in the adult group (P > 0.05). CONCLUSIONS: The asymmetry of nasal soft and hard tissues in patients with repaired UCLP becomes more apparent in the horizontal and sagittal dimensions from adolescence to adulthood. The correlation between the asymmetry of nasal hard tissue and soft tissue becomes stronger in the horizontal and sagittal dimensions. These factors should be taken into account when performing treatment for repaired UCLP patients in adolescence and adulthood.

Ultrasonic Evaluation of the Asian Nasal Soft Tissue Envelope.

OBJECTIVE: The thickness of the nasal soft tissue envelope (STE) plays a crucial role in the final rhinoplasty results. The Asian nasal contour is typically characterized by a thicker STE and broader nasal tip, but objective data are lacking. The purpose of this study was to objectively measure nasal dermal thickness and overall STE thickness and to determine any demographic differences. METHODS: From July to September 2023, 110 patients presenting for consultation underwent ultrasound evaluation of their nasal STE. STE thickness was measured at predetermined subsites and compared with published data on white patients. RESULTS: The thickness of the STE in Asian patients was greater than that in white patients. The STE was thickest at the supratip (mean [SD]), (4.88 [0.74] mm) rather than at the nasion and thinnest at the rhinion (2.25 [0.51] mm). The nasal tip (4.07 [0.72] mm) showed comparable STE thickness with the nasion (4.13 [0.72] mm) but had a significantly thicker dermis than the nasion (2.35 ± 0.49 mm vs. 1.35 ± 0.35 mm, P < 0.05). Male sex and higher BMI tended to be correlated with a thicker nasal STE, but age did not show any relationship. A thicker nasal tip STE showed significantly greater nasal tip width and nasal alar thickness. CONCLUSION: STE thickness at different nasal subsites varies and affects external nasal contour and rhinoplasty outcomes. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Radiographic Study of the Nasal Valve in Different CT Evaluation Method in Asian Patients with Unilateral Cleft Lip Nose.

OBJECTIVE(S): It was the first study to apply and compare two CT methods to assess the validity and clinical significance of structural alterations of the nasal valve in patients with cleft lip nose for assessing nasal ventilation disturbance. METHODS: The study collected data from the NOSE score, as well as internal nasal valve area, internal nasal valve angle, external nasal valve area, and septal deviation angle, to evaluate the differences and correlations between those factors in patients with cleft lip and nose. RESULTS: There were significant differences among INV transverse and coronal area and INV angle on different axial standardized planes between clefted side and non-clefted side. There were statistically significant negative correlations between NOSE scores and those indicators of standard plane and acoustic-axis standardized coronal plane. NOSE score and NSD angle were the indicators of significant differences in the measured data of different complications groups (p = 0.002, p = 0.017). The correlation comparison showed that two standardized CT imaging transverse planes have similar correlations in NOSE score, NSD angle, and complications. CONCLUSION: The results of the two CT evaluation methods showed that there was a significant difference in nasal valve area on the cleft and non-cleft sides, which was significantly associated with nasal ventilation disturbance. The CT evaluation method based on standard axial 3D reconstruction is more convenient to use in the clinic, can be used for pre-surgical evaluation of nasal repair in patients with secondary nasal deformities of unilateral cleft lip, and is valuable for treatment. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Nasal Morphology in a Young Adult Middle-Eastern Population: A Stereophotogrammetric Analysis.

AIM: This study aimed to describe gender-specific three-dimensional morphology of the soft-tissue nose in Lebanese young adults and to explore the associations between nasal morphology with age and body mass index (BMI). MATERIALS AND METHODS: Three-dimensional photographs were captured for 176 young healthy Lebanese adults (75 males and 101 females) aged 18.1-37.68 years. Linear and angular nasal measurements were computed and compared between genders, in addition to other established norms. Associations with age and BMI were also assessed. RESULTS: All linear measurements were greater in males than in females, and only the nasolabial angle was significantly larger in females by 2.97 degrees on average. Most of the measurements were found to be larger than the Caucasian norms. A few significant correlations were found between the measurements and age or BMI. CONCLUSION: This study is the first to present the sex-specific norms for nasal morphology in the Lebanese population and highlights the presence of gender dimorphism in the majority of measurements. Additional studies are needed to validate our data and expand the associations with age and BMI. CLINICAL SIGNIFICANCE: The data offered in this study could help enhance the accuracy of facial reconstructive surgery and aid in personalized treatment planning for both medical and cosmetic nasal interventions. How to cite this article: Saadeh M, Shamseddine L, Fayyad-Kazan H, et al. Nasal Morphology in a Young Adult Middle-Eastern Population: A Stereophotogrammetric Analysis. J Contemp Dent Pract 2024;25(3):199-206.

Analysis of select esthetic nasal parameters in virtually planned orthognathic patients.

PURPOSE: Bony changes after orthognathic surgery are always followed by changes of the overlying soft tissues. Therefore, morphologic changes of the nose may be expected after procedures involving the maxilla. The purpose of this study was to evaluate the changes in the nasal region due to orthognathic surgery using computed tomography (CT) images of virtually planned patients. METHODS: 35 patients who underwent Le Fort I osteotomy, with or without bilateral sagittal split osteotomy, were included. 3D measurements on preoperative and postoperative images were performed and analyzed. RESULTS: The results revealed that aesthetically acceptable results can be achieved by orthognathic surgery alone. CONCLUSIONS: According to the results of this study, it can be concluded that it is best to reserve decisions on rhinoplasty to the post-orthognathic period.

What is the impact of miniscrew-assisted rapid palatal expansion on the midfacial soft tissues? A prospective three-dimensional stereophotogrammetry study.

OBJECTIVES: To evaluate the midfacial soft tissue changes of the face in patients treated with miniscrew-assisted rapid palatal expansion (MARPE). MATERIALS AND METHODS: 3D facial images and intra-oral scans (IOS) were obtained before expansion (T0), immediately after completion of expansion (T1), and 1 year after expansion (T2). The 3D images were superimposed and two 3D distance maps were generated to measure the midfacial soft tissue changes: immediate effects between timepoints T0 and T1 and overall effects between T0 and T2. Changes of the alar width were also measured and dental expansion was measured as the interpremolar width (IPW) on IOS. RESULTS: Twenty-nine patients (22 women, 7 men, mean age 25.9 years) were enrolled. The soft tissue in the regions of the nose, left of philtrum, right of philtrum, and upper lip tubercle demonstrated a statistically significant anterior movement of 0.30 mm, 0.93 mm, 0.74 mm, and 0.81 mm, respectively (p < 0.01) immediately after expansion (T0-T1). These changes persisted as an overall effect (T0-T2). The alar width initially increased by 1.59 mm, and then decreased by 0.08 mm after 1 year, but this effect was not significant. The IPW increased by 4.58 mm and remained stable 1 year later. There was no significant correlation between the increase in IPW and alar width (r = 0.35, p = 0.06). CONCLUSIONS: Our findings indicate that MARPE results in significant but small changes of the soft tissue in the peri-oral and nasal regions. However, the clinical importance of these findings is limited. CLINICAL RELEVANCE: MARPE is an effective treatment modality to expand the maxilla, incurring only minimal and clinically insignificant changes to the midfacial soft tissues.

Evaluation of Skin-Soft Tissue Envelope Thickness by Ultrasonography after Primary and Revision Rhinoplasty.

BACKGROUND: Excessive nasal edema is among the complications after rhinoplasty translating into Skin-Soft Tissue Envelope (SSTE) thickening and disruption in the nasal framework's definition. Revision rhinoplasties are suspected of causing even more nasal edema. The objective postoperative SSTE thickness between revisionary and primary rhinoplasties is compared in this study. METHODS: A study was conducted over a recorded database of eligible candidates who had attended the senior author's private clinic in a 12-month period and underwent primary and revisionary open-approach rhinoplasties. The SSTE thickness was measured by ultrasonography in each nasion, rhinion, supratip, and tip region at months 1, 3, 6, and 12 after each episode of rhinoplasty. Paired T-test was used for pairwise comparisons of the corresponding region-time thicknesses between primary and revisionary rhinoplasties. Repeated measure ANOVA tests were used to assess mean thickness changes over time after each surgery-P < 0.05 indicated significance. RESULTS: Of the 36 participants analyzed, the SSTE was significantly thicker after revisionary surgery in all the follow-up sessions and nasal regions, except for the 1-month follow-up in the nasion (p = 0.273) and 12-month follow-up in the rhinion (p = 0.050). Mean nasal SSTE thickness showed decreasing trends in each region after either primary or revisionary surgery, with a lower level of resolution in the nasion region after revision rhinoplasty (p < 0.001). CONCLUSIONS: The nasal SSTE had been significantly thicker in most regions after revisionary procedures than primary ones, and the swelling had subsided slightly slower. Surgeons are recommended to consider revisionary rhinoplasties based on these findings cautiously. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A Clinical Report of the Complete Nasal Agenesis: Reconstruction of Congenital Arhinia and Review of the Literature.

Congenital absence of the nose or arhinia is an exceptionally rare craniofacial malformation, and the pathophysiology of the arhinia is still unknown. Most arhinia patients can have difficulties with breathing and feeding due to the absence of the nose, nasal cavities, and associated problems. A 38-day-old female patient was referred to our clinic with arhinia. Physical examination revealed the complete agenesis of nasal structures as the nasal bones and vestibulum nasi. The region of the absent nose was flat and firm at palpation. Congenital arhinia may occur with other associated malformations such as ocular, ear, palate, and gonadal. Therefore, it is recommended to evaluate computed tomography/magnetic resonance imaging in the postnatal period. Additionally, a radiological evaluation will help nasal reconstruction by documenting changes in nasal and maxillary anatomy over time. Due to the limited number of arhinia cases presented, the surgical management of this condition has not been standardized. We presented the pyramid-shaped cartilage grafts for the nasal framework and an expanded paramedian forehead flap for the skin coverage for reconstruction of arhinia.

Proboscis Lateralis With Basal Encephalocele: A Report of Clinical Management and Reconstructive Approach.

Proboscis lateralis is a rare craniofacial anomaly in which a rudimentary nasal appendage arises at the medial canthal area. The severity depends on organ involvement, including eyes, nose, cleft lip/palate, and/or concomitant intracranial anomalies. Here, we present a child with proboscis lateralis and associated trans-ethmoidal encephalocele. We suggest doing the preoperative CT and/or MRI to rule out associated intracranial anomalies and reliably preoperative planning tools. Moreover, we proposed an alternative nasal reconstructive technique using a composite graft from the proboscis mass at the same time as encephalocele repair with promising results.

Cleft Nasal Stent Production Using Three-Dimensional Scanning and Printing Technology.

ABSTRACT: In most cleft centers worldwide, nasal stents are routinely used in the postoperative period to prevent collapse of the lower lateral cartilage and maintain the shape of the nostrils as well as nasal alar. Prefabricated nasal stents are expensive and do not offer options for customization. In this paper, we introduce a cost-effective technique for manufacturing nasal stents using three-dimensional scanning and printing technology.

Forehead Flap Templates for Nasal Reconstruction Digitally Developed From 2D and 3D Images.

ABSTRACT: The forehead flap is the gold standard procedure for nasal reconstruction to address a partial or complete rhinectomy. Traditionally, the three-dimensional (3D) nasal defect is manually templated intraoperatively to design the two-dimensional (2D) flap shape on intact morphology. In this clinical study, digital preoperative planning is used to template with computer-assisted design and manufacturing. Preoperative digital templates were implemented for 3 representative patients (1 in Supplementary Digital Content, http://links.lww.com/SCS/D60). This includes designs for a hemi-rhinectomy case from 3D mirroring, a partial total rhinectomy case generated from a 3D scan, and a total rhinectomy case generated from a 3D morphable model based on a prepathology 2D photo. Digital unwrapping flattened the patient's 3D nasal geometry designs to 2D skin flap shapes. Finally, the 2D designs were printed as traceable intraoperative templates at a 1:1 scale. This clinical study demonstrates the application of digital 3D preoperative templating to improve workflow for nasal reconstruction.

Vasculature of the Nasal Cartilage Region Related to Filler Injection.

BACKGROUND: A filler injection in the nose can be essential but is also dangerous, especially in the nasal cartilage region. To safely and accurately perform a filler injection, surgeons must have detailed knowledge of nasal anatomy. OBJECTIVES: Associated the vessel branches and the characteristics of different nasal regions to provide suggestions for more suitable injection sites. METHODS: Fifty specimens underwent computed tomography (CT) after contrast infusion. Qualified specimens were selected for 3D CT reconstruction. Dissection was performed to confirm the accuracy of the CT data. RESULTS: The branches of arteries with large diameters, the dorsal nasal artery (DNA) and the lateral nasal artery (LNA) were distributed within the superficial musculoaponeurotic system layer. The DNA was seen in only 58% of specimens. The artery crossed the midline over the upper lateral cartilage in 16% of specimens. The LNA was a constant branch that traversed the nasal tip. The LNA crossed the midline to the contralateral side in 18% of patients. We divided the nasal cartilage dorsum into two regions for easy handling: the supratip region (STR) and the nasal tip region (NTR). The branches distributed in the STR mostly originated from the DNA (81.6%, 40/49), while those in the NTR mostly originated from the LNA. CONCLUSIONS: The vasculature of the nasal cartilage region observed in this study is similar to that observed in previous studies. However, we found that the STR was an advantageous area for filler injection. At the same time, we provided suggestions for more suitable injection methods. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Simultaneous Fat Injection for Nasal Contouring in Orthognathic Patients.

BACKGROUND: Augmentation rhinoplasty with autologous fat grafting is a useful procedure to meet the demand for facial harmonization in the Asian population. We used this procedure during orthognathic surgery to address inadequate dorsum projection. This prospective study was conducted to determine the fat retention rate in patients undergoing simultaneous autologous fat injection augmentation rhinoplasty and orthognathic surgery. METHODS: Nineteen patients were treated with simultaneous bimaxillary orthognathic surgery and autologous fat grafting of the nasal dorsum and tip. The paired t test was used to compare the nasal volumes before and at least 6 months after surgery measured by 3-dimensional computer tomography scans. All measurements were performed twice by the same evaluator at least 2 weeks apart for intrarater consistency. RESULTS: Seventeen patients completed the study. The volume means before and after surgery were 22.3 ± 4.6 cm3 and 23.3 ± 4.7 cm3, respectively, with a mean difference of 1.0 ± 0.3 cm3 (P < .001). The mean retention rate was calculated to be 50.5% ± 7.0% (range: 40.5%-64.7%). Intrarater consistency was high with a Cronbach α of .97 (P < .001) and .98 (P < .001), respectively. CONCLUSION: This prospective study provides objective graft retention measurements for fat injection augmentation rhinoplasty combined with orthognathic surgery. All patients were satisfied with the results and no complications or additional morbidity was noted in the postoperative course. We consider this procedure to be a safe, reliable, and powerful adjunct to improve the aesthetic results of orthognathic surgery.

Reconstruction of Congenital Arhinia With Stereolithographic Modeling: Case Correlate and Literature Review.

Complete congenital arhinia is a rare defect of embryogenesis leading to the absence of the external nose and airway. We report our novel multistaged reconstructive approach and literature review. Nasal methyl methacrylate prosthesis was created from a stereolithographic model for use as a temporary prosthesis and tissue expander. Lefort 1 with cannulization was utilized for midface advancement and airway formation. External framework was reconstructed with bilateral conchal bowl cartilage and rib osteocartilagenous grafts. Patient was pleased with the aesthetics and had safe decannulation with the ability to breathe through the nose and airway.

Morphologic reproducibility in 6 regions of the 3-dimensional facial models acquired by a standardized procedure: An in vivo study.

INTRODUCTION: A standardized procedure was proposed to control involuntary motion and other factors during the capture of structural light scanning that could influence the morphology of 3-dimensional facial models; interoperator reproducibility was evaluated. METHODS: Twenty subjects volunteered for facial scanning. Three researchers scanned each volunteer 3 times on the same day using the FaceScan structural light scanning system (Isravision, Darmstadt, Germany) and after the proposed procedure. Captures were done at 5-minute intervals. The 3 facial scans acquired by the same researcher were compared by reverse engineering software (Geomagic; 3D Systems, Rock Hill, SC). Six facial regions, including forehead, nose, paranasal, upper lip, lower lip and chin, and cheek, were divided. With the first scan as a reference, the other 2 scans were registered, and surface-to-surface distance maps were acquired to calculate the mean, standard deviation, and root mean squares (RMS) between 2 surfaces. The reproducibility between 3 researchers was then evaluated by a 1-way analysis of variance. RESULTS: The mean of 6 facial regions was close to 0. The RMS of lip regions were largest (0.48-0.53 mm), the forehead was smallest (0.21 mm), and the others ranged 0.37 mm to 0.42 mm. The standard deviation was slightly smaller than RMS and had the same trend of change. There was no significant difference in RMS among the 3 researchers (P >0.05). CONCLUSIONS: With the constraint of the standardized procedure, the morphologic reproducibility of facial models in 6 regions was satisfying.