Angular Cephalometric Measurements Research Articles

Craniofacial and Airway Morphology in Down Syndrome: A Cone Beam Computed Tomography Case Series Evaluation.

Background: Down syndrome (DS) is a genetic condition characterized by an extra copy of chromosome 21, resulting in various physical and cognitive features. This study aimed to comprehensively analyze the dental and craniofacial morphology of individuals with DS using Cone Beam Computed Tomography (CBCT). Methods: Six individuals with DS, comprising five males and one female aged 17 to 35 years, underwent CBCT scanning. Radiographic assessments included dentition, occlusion, paranasal sinuses, airway, skull bones, and suture calcification. Linear and angular cephalometric measurements were performed, and airway analysis was conducted using Dolphin 3D imaging software v.11. Results: The study revealed prognathic maxilla in five patients, prognathic mandible in four, and bimaxillary protrusion in two. Dental findings included microdontia, enamel hypoplasia, and congenitally missing teeth, with maxillary and mandibular third molars most commonly absent. Sinus abnormalities, delayed suture closure, and cervical spine anomalies were also observed. Conclusion: These findings contribute to a deeper understanding of DS-related craniofacial characteristics and emphasize the importance of considering these morphometric features in clinical management strategies for individuals with DS. This study's limited sample size underscores the significance of radiographic assessment in planning interventions such as cosmetic reconstructions, prosthetic rehabilitation, or orthodontic treatment for individuals with DS.

Curve of Spee modification in different vertical skeletal patterns after clear aligner therapy: a 3D set-up retrospective study

ObjectiveThe purpose of the present study was to evaluate: (1) changes in the curve of Spee (COS) after clear aligner therapy and (2) whether such changes correlated with the patient’s skeletal patterns.Materials and methodsThree-dimensional mandibular models of 106 patients (47 males and 59 females; mean age 22.3 SD ± 3.4 years) treated with clear aligners were retrospectively analysed. The perpendicular distance between the occlusal reference plane and the buccal cusp tip of each lateral tooth was measured. Five angular cephalometric measurements (PP-MP, PP-OP, OP-MP, AFH, and PFH) were performed and correlated with the T1–T0 difference in linear distances. The patients were divided into three groups according to facial divergence. Variance analysis with Tukey post hoc correction was performed to evaluate the differences among groups.ResultsThe one-way ANOVA test showed a statistically significant difference for all analysed variables, except for the change in the distance of the second molar from the occlusal reference plane. Tukey’s HSD test showed the following differences: In normodivergents, the T1–T0 difference in the distance of the first molar from the occlusal plane was 1 mm greater than that observed in the hyperdivergent group (p < 0.05); in the normodivergent group, the T1–T0 difference in the distance of the second premolar from the occlusal plane was 1.23 mm greater than that observed in the hyperdivergent group (p < 0.05), while in the hypodivergent group, it was 1.08 mm greater than in the hyperdivergent group (p < 0.05); finally, in normodivergents, the T1–T0 difference in the distance of the first premolar from the occlusal plane was 0.97 mm greater than that observed in the hyperdivergent group (p < 0.05).ConclusionTreatment with aligners did not lead to a clinically significant change in COS depth. However, when dividing the sample into groups based on craniofacial divergence, COS depth change differed significantly between the three groups.

Evaluation of effectiveness and efficiency of fixed orthodontic treatment comparing standard and computer-aided design and manufacturing conventional bracket systems using indirect bonding for both: A retrospective study

To compare the effectiveness and efficiency of orthodontic treatment (OT) with standard versus computer-aided design and computer-aided manufacturing (CAD/CAM) indirect bonding of conventional brackets. This retrospective study examined two groups: standard indirect bonding group (12 males, 13 females; mean age 12.21 ± 0.52 years), and digital indirect bonding group (11 males, 14 females; mean age 12.76 ± 1.32 years), treated via a CAD/CAM indirect bonding system. Conventional brackets were used in both groups. Pretreatment and post-treatment records were acquired for all subjects. Weighted Peer Assessment Rating (W-PAR) index was used to assess the effectiveness of OT, in conjunction with five angular cephalometric measurements (ANB°, Sn-GoGn°, U1-PP°, IMPA° and FMA°) and comparatively analyzed using generalized mixed-effects models and post hoc test. Treatment efficiency was assessed in terms of the numbers of bracket repositionings, archwire bends, accidental bracket debondings, appointments and treatment months. Comparative analysis of efficiency was performed using the asymptotic Wilcoxon-Mann-Witney test. Statistical significance was set at 5%. Total W-PAR and W-PAR component scores decreased significantly during treatment for both groups and in a similar way. Cephalometric measures ANB° and IMPA° significantly decreased and increased, respectively. Significantly fewer bracket repositionings, number of appointments and treatment months were recorded in group digital indirect bonding. Although both methods investigated were effective to achieve good outcomes, CAD/CAM indirect bonding method increased the efficiency of OT, when conventional brackets are used.

Assessment of angular cephalometric measurements for the analysis of vertical growth trend and angle Z in a sample of patients with normal occlusion

This study aimed to evaluate the angular measurements and facial characteristics of individuals from the city of Rio de Janeiro, Brazil, using cephalometry. For this study, 531 male individuals from military organizations in Rio de Janeiro were submitted to the clinical record of the Master’s degree in Orthodontics course of the Research Center – São Leopoldo Mandic. Of this sample, it was observed that 22 individuals had normal occlusion and had never undergone orthodontic treatment. In these patients, lateral cephalograms were taken and the cephalometric measurements were evaluated: Y-axis, NS.Go-Me, SN.PLO, FMA, SN-Go-Gn, angle Z, among others. The data obtained were subjected to analysis with a significance level of 5% (p&lt;0.05) and descriptive statistics and the Dahlberg error were used. The results showed that individuals with normal occlusion from the city of Rio de Janeiro presented these cephalometric characteristics within the normal standards as already described in the literature.

Comparison of angular cephalometric measurements between CBCT mid-sagittal plane projections and conventional lateral cephalometric radiographs

The purpose of this study was to verify the angular measurement values of conventional Lateral Cephalometric Radiographs (LCRs) and Cone-Beam Computed Tomography (CBCT) Mid- Sagittal Plane (MSP) projections when using the same cephalometric analysis method.

Reproducibility of linear and angular cephalometric measurements obtained by an artificial-intelligence assisted software (WebCeph) in comparison with digital software (AutoCEPH) and manual tracing method.

It has been suggested that human errors during manual tracing of linear/angular cephalometric parameters can be eliminated by using computer-aided analysis. The landmarks, however, are located manually and the computer system completes the analysis. With the advent of Artificial Intelligence in the field of Dentistry, automatic location of the landmarks has become a promising tool in digital Orthodontics. Fifty pretreatment lateral cephalograms obtained from the Orthodontic department of SRM dental college (India) were used. Analysis were done by the same investigator using the following methods: WebCeph™, AutoCEPH© for Windows or manual tracing. Landmark identification was carried out automatically by Artificial Intelligence in WebCeph™ and with a mouse driven cursor in AutoCEPH©, and manually using acetate sheet and 0.3-mm pencil, ruler and a protractor. The mean differences of the cephalometric parameters obtained between the three methods were calculated using ANOVA with statistical significance set at p<0.05. Intraclass correlation coefficient (ICC) was used to determine both reproducibility and agreement between linear and angular measurements obtained from the three methods and intrarater reliability of repeated measurements. ICC value of >0.75 indicated good agreement. Intraclass correlation coefficient between the three groups was >0.830, showing good level of agreement, and the value within each group was >0.950, indicating high intrarater reliability. Artificial Intelligence assisted software showed good agreement with AutoCEPH© and manual tracing for all the cephalometric measurements.

Occlusal Plane Modification in Clear Aligners Treatment: Three Dimensional Retrospective Longitudinal Study.

The purpose of the present study was to evaluate: (i) maxillary occlusal plane changes after clear aligners therapy with a 3D measurement technique; and (ii) as a secondary outcome, if such changes were correlated to the patient’s 1axilla-mandibular divergence. 3D maxillary models of 32 patients (7 males and 25 females; mean age 22.3 +/− 3.4 year) treated with clear aligners were analyzed. The angle (α) between a reference palatine plane and a maxillary occlusal plane was measured. Five angular cephalometric measurements (NSL/MP; PP-OP; OP-MP; PP-MP; PFH/AFH%) were performed and related to Δα. The subjects were further divided into three groups according to facial divergence. After aligner treatment, Δα increased in hyperdivergent patients and decreased in hypodivergent patients (p < 0.05). Δα showed a significant positive correlation with NSL/MP (rho = 0.44) and negative correlation with PFH/AFH% (rho = −0.53). Aligners treatment produced a counterlockwise rotation of the maxillary occlusal plane, even if this rotation occurs differently depending on divergence.

Gender differences in cephalometric angular measurements between boys and girls

Background: Gender determination is an important aspect of human biologic profile identification. The human skull is part of the body that has many gender indicators. Lateral cephalogram is used for human skull analysis because of its morphological biologic details, including gender. Purpose: The objective of this study was to determine the difference of angular measurements, those are sella-nasion-point A (SNA), sella-nasion-point B (SNB), point A-nasion-point B (ANB), gonial, mandibular plane, glabella-metopion and sella-nasion (GM-SN), glabella-metopion and Frankfort horizontal plane (GM-FHP), and glabella-metopion and basion-nasion (GM-BaN) angles measurement’s results between boys and girls aged 8-12 years. Methods: This study was an observational analytic on cephalometric radiographs in children aged 8-12 years from July-December 2018 using 54 samples from the Faculty of Dentistry Universitas Trisakti’s Oral and Dental Hospital Radiology Installation. Landmarks determination and angular measurement were digitized. The data were analyzed to a univariate test followed by a statistical test using the independent t-test. Results: The independent t-test showed there are no differences between boys’ and girls’ angular measurement results (p &gt; 0.05). Conclusion: There are no differences in the angular measurements results between boys and girls aged 8-12 years.

Craniofacial form differences between obese and nonobese children

Current evidence suggests that obesity is correlated with differences in craniofacial form in children and adolescents. Here, we sought to test this hypothesis by evaluating the craniofacial form of obese and nonobese preorthodontic patients, using 2D cephalometric data combined with cephalometric and geometric morphometric approaches. Height, weight, age, and lateral cephalometric radiographs were gathered from patients aged 7-16 years before beginning orthodontic treatment at the University of British Columbia. Based on their body mass index, 24 obese patients were age, sex, and Angle classification of malocclusion matched with nonobese controls. Cephalometric radiographs were annotated, and coordinates of landmarks were used to obtain linear and angular cephalometric measurements. Geometric morphometric analyses were performed to determine overall craniofacial form differences between cohorts. Dental maturation index scores and cervical vertebral maturation scores were recorded as an indicator of skeletal maturation. Cephalometric analysis revealed that the maxillary length and gonial angle are the only marginally larger metrics in obese subjects than in control subjects. However, principal component and discriminant analyses (geometric morphometrics) confirmed that the overall craniofacial form of obese patients differs statistically from that of control patients. Obese patients tend to be slightly mandibular prognathic and brachycephalic. Dental maturation index scores were statistically higher in the obese group than in the control group, with no statistical difference in cervical vertebral maturation scores. Our data reveals a subtle but significant difference in cranial skeletal morphology between obese and nonobese children and adolescents, suggesting a correlation between craniofacial form and physiological/metabolic phenotypes of subjects. It is likely that with continued growth, these differences may increase. Recording body mass index as part of the orthodontic records for patients may help in supporting the assessment of craniofacial form.

Evaluation of fully automated cephalometric measurements obtained from web-based artificial intelligence driven platform

BackgroundArtificial Intelligence has created a huge impact in different areas of dentistry. Automated cephalometric analysis is one of the major applications of artificial intelligence in the field of orthodontics. Various automated cephalometric software have been developed which utilizes artificial intelligence and claim to be reliable. The purpose of this study was to compare the linear and angular cephalometric measurements obtained from web-based fully automated Artificial Intelligence (AI) driven platform “WebCeph”™ with that from manual tracing and evaluate the validity and reliability of automated cephalometric measurements obtained from “WebCeph”™.MethodsThirty pre-treatment lateral cephalograms of patients were randomly selected. For manual tracing, digital images of same cephalograms were printed using compatible X-ray printer. After calibration, a total of 18 landmarks was plotted and 12 measurements (8 angular and 4 linear) were obtained using standard protocols. The digital images of each cephalogram were uploaded to “WebCeph”™ server. After image calibration, the automated cephalometric measurements obtained through AI digitization were downloaded for each image. Intraclass correlation coefficient (ICC) was used to determine agreement between the measurements obtained from two methods. ICC value < 0.75 was considered as poor to moderate agreement while an ICC value between 0.75 and 0.90 was considered as good agreement. Agreement was rated as excellent when ICC value > 0.90 was obtained.ResultsAll the measurements had ICC value above 0.75. A higher ICC value > 0.9 was obtained for seven parameters i.e. ANB, FMA, IMPA/L1 to MP (°), LL to E-line, L1 to NB (mm), L1 to NB (°), S-N to Go-Gn whereas five parameters i.e. UL to E-line, U1 to NA (mm), SNA, SNB, U1 to NA (°) showed ICC value between 0.75 and 0.90.ConclusionA good agreement was found between the cephalometric measurements obtained from “WebCeph”™ and manual tracing.

Testosterone suppression impacts craniofacial growth structures during puberty : An animal study.

Hormones play acrucial role in growth development; however, the impact of testosterone suppression (TS) on craniofacial growth during puberty remains inconclusive. This study aimed to evaluate the impact of TS during puberty on cephalometric measurements and histological characteristics of facial growth centers. Thirty-six heterogenic Wistar male rats were randomly allocated into experimental orchiectomy (ORX) and control (sham) groups. At an age of 23days (prepubertal stage), orchiectomy and placebo surgery were performed. Cephalometric measurements were performed via lateral cephalograms during and after puberty. The animals were euthanized at an age of 45days (pubertal stage) and 73days (postpubertal stage). Histological slices of the growth centers (condyle, premaxilla, and median palatine suture) were stained with hematoxylin and eosin, and sirius red. Student'st or Mann-WhitneyUtests were used to compare linear and angular cephalometric measurements across groups (α error = 5%). Linear and angular measurements were statistically different in ORX animals (cranial bones, maxilla, and mandible) at 45days and 73days. Condylar histology showed adecrease in prechondroblast differentiation and adelay of mineralization in ORX animals. Vascularization of the medium palatine suture was lower in the ORX group at 45days. TypeI andIII collagen fiber synthesis was lower in the ORX groups. In the premaxillary suture, collagen fibers were better organized in the sham groups. Our results suggest that testosterone suppression affects craniofacial growth during puberty.

Craniofacial and Upper Airway Development in Patients With Treacher Collins Syndrome.

This study evaluated age-associated morphology changes in the cranial base, facial development, and upper airway of patients with Treacher Collins syndrome (TCS). A total of 33 preoperative computed tomographic images (TCS, n = 14; control, n = 19) were included in the study and divided into three age-related subgroups (2-6 years, 7-18 years, and older than 18 years). Linear, angular cephalometric measurements and upper airway volumes were collected. All measurements were analyzed using ProPlan CMF software (version 3.0; Materialize, Leuven, Belgium). The association between aging and upper airway morphology was analyzed. Compared to control subjects, TCS patients had a smaller cranial base, maxilla, and nose; they also had reduced upper airway volume compared to control subjects. The observed differences were most significant in patients between the ages of 7 and 18 years. This study used computed tomography-based three-dimensional analyses to provide a detailed description of age-related changes that occur in craniofacial measurements and upper airway volumes in children, adolescents, and young adult patients with TCS in China. These data can be used to evaluate individual patients with TCS and to select treatment to improve the growth of the craniofacial region.

Cephalometric norms for Bimaxillary Protrusion in Trinidad and Tobago: a preliminary study

ABSTRACT The aim of this study is to establish for the first time cephalometric norms for bimaxillary protrusion in Trinidad and Tobago population and to compare findings to previously published norms for other bimaxillary protrusion groups. Materials and Methods In total, 109 standardized lateral cephalometric radiographs were taken by one investigator of bimaxillary protrusion patients prior to receiving orthodontic treatment. The sample consisted of 52 boys and 57 girls aged 10–17 years. The cephalograms were traced using 48 hard and soft tissue and 25 linear and angular cephalometric measurements. Independent sample t-test was used to assess inter-gender differences, norms were calculated. The results were then compared to the norms for other bimaxillary protrusion populations. Results The mean values and standard deviations obtained were: SNA, 85.9° (± 4.9°); SNB, 78.7°(± 4.5°); ANB, 7.2°(± 2.5°); MMPA, 32.3°(±5.1°); UI-LI,109.7° (±8.2°); UI-Max, 118.7° (±6.1°); LI-Man, 101.4° (±5.9°); LI-Apo, 3.8° (±2.6°); Upper lip to E-plane 2.0 mm (±3) and Lower Lip to E-plane 5.6 mm (±3.2).The independent t-test showed sexual dimorphism with SNA and upper and lower lip to E-plane being higher in males compared to females. The maxilla and mandible were more anteriorly placed in this sample as compared to Caucasian norms. ANB, MMPA, UI-Max, LI-Man, LI-Apo, upper lip and lower lip to E-plane, were all higher in this population compared to other bimaxillary protrusion populations. Conclusions There are some fundamental differences in the cephalometric norms for the bimaxillary protrusion population in Trinidad and Tobago and in the context of orthodontic diagnosis and treatment planning these cephalometric norms should be the yardstick.

A Comparative Study on Use of Manual Versus Digital Method using Mobile Application for Cephalometric Measurements

Introduction: Various computer software and smartphone applications have been developed for digital cephalometric analysis with ease and in short time. The objective of this study was to compare linear and angular cephalometric measurements obtained, and cephalometric tracing duration between smartphone application tracing (app method) and conventional tracing (manual method) methods.&#x0D; Materials &amp; Method: 35 digital Lateral cephalometric radiographs of patient who came for orthodontic treatment were collected. Measurements of cephalometric parameters of composite analysis were obtained with manual and smartphone application (OneCeph) method and compared statistically. Cephalometric tracing duration was also compared between two methods.&#x0D; Result: Cephalometric tracing duration using manual method was found to be significantly higher (p&lt;.001) than that of the app method. There was no significant difference in values of SNA, SNB, ANB, Nasion perpendicular to point A, Nasion perpendicular to pogonion (pog), Angle of convexity, Go-GN/SN, FMA, U1–NA (degree), U1-NA (linear), L1–NB (degree), Cant of Occlusion, Interincisal angle, Nasolabial angle, Upper lip to Steiner’s S line, Lower lip to Steiner’s S line obtained with the manual and application method. The values of linear measurement between Lower incisor to NB line showed significant difference (p&lt;0.05).&#x0D; Conclusion: Although there was no significant difference in cephalometric measurement, cephalometric tracing duration of cephalometric analysis using Smartphone application was significantly faster than that of conventional method.

CEPHALOMETRIC SKELETAL COMPARATIVE ANALYSIS BETWEEN LEFT AND RIGHT SIDE OF SKULL FOR TWO AGE GROUPS PATIENTS WITH CLASS ONE MALOCCLUSION BY THREE DIMENSIONAL CONE-BEAM COMPUTED TOMOGRAPHY

Objective: The purpose of our research was to study comparative cephalometric analysis between left and right sides of head and evaluate the skeletal facial symmetry in patients with class 1 malocclusion by 3D Cone-beam computed tomography (CBCT). Materials and Methods: Pre-treatment by 3D Cone-beam computed tomography radiographs for 20 patients of two age groups with class 1 malocclusion was undergone for 11 angular and 4 liner measurements from right and left sides, anteroposterior, vertical and frontal view by hand except the hard landmarks determination. Chi-test was used to compare the result of both sides (P &lt; 0.05). Results: No difference was found between left and right analysis for linear measurements as for the angular cephalometric measurements. Conclusion: Measurements of skeletal analysis by 3D CBCT cephalograms from right side were found to be similar to left side. So, we can use the left analysis for orthodontics diagnosis as right side. Also, the both sides analysis can be used for symmetric analysis reasons.

Immediate and late follow-up effects of class III early correction in cleft lip and palate patients treated with maxillary protraction

Abstract Introduction There is no consensus about the immediate and latte follow-up effects of maxillary protraction in cleft lip and palate patients. Objective To evaluate the stability of Class III early treatment in cleft lip and palate patients through maxillary expansion and protraction. Material and method The sample consists in three lateral cephalometric radiographs of 28 patients (mean pre-treatment age of 6.7±1.8 years) who presented cleft lip and palate and were treated with maxillary expansion and Petit facial mask. The angular (SNA, SNB, ANB, SN.GoGn, FMA, Z Angle) and linear (overjet, Co-A, Co-Gn, Nperp-A, Nperp-Pg, AO-BO) cephalometric measures were evaluated through the Dolphin® software, in three moments: T0 (initial), T1 (after treatment), and T2 (follow-up). Data were submitted to the analysis of variance (ANOVA) and Tukey-Kramer test. The correlation between cephalometric measures and patient’s age was determined by Pearson’s chi-squared test. Result The SNA, ANB, and AO-BO measures increased considerably (p&lt;0.05), and they did not present any differences compared to the initial ones after the follow-up time. The overjet measure increased (p&lt;0.05) after treatment and, even with its decrease at the follow-up time, it was still higher than at the beginning (p&lt;0.05). The Z angle showed improvement with treatment and remained stable at the follow-up time. Conclusion After treatment (maxillary expansion associated with protraction), there was a skeletal pattern improvement. During the follow-up period, those alterations decreased to a measure close to the beginning. There was an improvement in the dental pattern and facial profile that continued in the follow-up period.

Adding Depth to Cephalometric Analysis: Comparing Two- and Three-Dimensional Angular Cephalometric Measurements.

Lateral cephalometric radiographs (LCR) have been the standard tool used for cephalometric analysis in craniofacial surgery. Over the past decade, a three-dimensional (3D) revolution in cephalometric analysis and surgical planning has been underway. To date, research has not validated whether cephalometric measurements taken from two-dimensional (2D) and 3D data sources are equivalent and interchangeable. The authors sought to compare angular cephalometric measurements taken with 2D and 3D modalities. Sixty-two head CT scans (36 females, 26 males) with an average age of 63 ± 20 years were studied. Twelve cephalometric angular measurements were taken from 3D reconstructed skulls using the software package Mimics 19.0 (Materialize; Leuven, Belgium). These same facial angles were measured from 2D lateral cephalograms reconstructed from the original CT scans using Dolphin 11.9. Measurements taken with both techniques were compared for agreement using a paired t test. Intra-class correlation coefficient assessment was used to determine inter-rater reliability. Statistical significance was set at P < 0.05. Five of the 12 angular measurements (SNA, SNB, MP-FH, U1-SN, and U1-L1) demonstrated statistically significant differences (P < 0.05) between the 2D and 3D analyses. All of these differences were less than the standard deviations for the respective measure. The differences between angular cephalometric values obtained from 2D LCRs and 3D CT reconstructions are small. This supports the practices of using 2D and 3D cephalometric data interchangeably in most applications. Clinicians must be selective in which measures they employ to maximize accuracy and care must be taken when measuring dental inclination with lateral cephalograms.

Palatally displaced maxillary lateral incisors maybe a causative factor of mandibular deficiency

Introduction: Several factors play a role in the etiology of skeletal Class II malocclusion. Displaced maxillary incisors might have a hindering effect on mandibular growth potential. Aim of the study: The aim of this cross-sectional study was to evaluate the influence of palatally displaced maxillary incisors on mandibular growth in a group of Egyptian patients. Subjects and Methods: The sample consisted of the digital lateral cephalometric radiographs of untreated 24 patients (12 females and 12 males) with age range of 15-30 years and a mean age of 22.4 years during the permanent dentition stage. The radiographs were selected from the patient database of private practice in Cairo. The sample was divided into 2 groups each consisting of 12 patients. Group A had palatally displaced maxillary lateral incisors without crossbite. Group B had palatally displaced maxillary lateral incisors with crossbite. Linear and angular cephalometric measurements (ANB & Witts appraisal) were used to assess the anteroposterior skeletal malocclusion and the position of the apical bases of the jaws in both groups. Independent samples t-test was performed to compare the results between the two groups. Results: Cephalometric measurements revealed statistically significant differences between groups A and B showing a mild skeletal Class II malocclusion with a retrognathic mandible in Group A (mean ANB = 4.4˚ ± 1.85), (mean Witts= 1.85 mm ± 3.22) while Group B had skeletal Class I pattern with mild skeletal Class III tendency (mean ANB= 0.8˚± 1.88), (mean Witts=-2.5mm ± 2.33). Conclusions: Palatally displaced maxillary lateral incisors without crossbite cause restraining effect on normal mandibular growth which results in mild skeletal Class II with mandibular deficiency. However, palatally displaced maxillary lateral incisors that are in crossbite have no restraining effect on mandibular growth which results in normal to slightly excessive mandibular growth. This can be used as a tool for early prediction of mandibular growth pattern that necessitates immediate intervention.

Abstract QS5: Adding Depth to Cephalometric Analysis: Comparing 2D and 3D Angular Cephalometric Measurements

PURPOSE: Lateral cephalometric radiographs (LCR) have been the standard tool used for cephalometric analysis in craniofacial surgery. Over the past decade, a 3D revolution in cephalometric analysis and surgical planning has been underway. To date, research has not validated whether cephalometric measurements taken from 2D and 3D data sources are equivalent and interchangeable. METHODS: A total of 62 head CT scans (36 females, 26 males) with an average age of 63 ± 20 years were selected. Twelve cephalometric angular measurements were taken from 3D reconstructed skulls using the software package Mimics 19.0 (Materialize; Leuven, Belgium). These same facial angles were measured from 2D lateral cephalograms reconstructed from the original CT scans using Dolphin 11.9. Measurements achieved with both techniques were compared for agreement using a paired t-test. Intra-class correlation coefficient assessment was used to determine inter-rater reliability. Statistical significance was set at p<0.05. RESULTS: Five of the 12 angular measurements (SNA, SNB, MP-FH, U1-SN, and U1-L1) demonstrated statistically significant differences (p<0.05) between the 2D and 3D analyses. All of these differences were less than the standard deviations for the respective measure. CONCLUSION: The differences between angular cephalometric values obtained from 2D LCRs and 3D CT reconstructions are small. This supports the practices of using 2D and 3D cephalometric data interchangeably in most applications. Clinicians must be selective in which measures they employ to maximize accuracy and care must be taken when measuring dental inclination with lateral cephalograms.

Lateral Cephalometric Standards for Mongolian 6-15 Year Old Children with Normal Occlusion

Objectives: The aim of this study was to establish the age and gender-specific lateral cephalometric standards for Mongolian children with normal occlusion. Methods: A total of 541 children between 6 and 15 years of age were selected based on the normal occlusion criteria. Lateral cephalograms of each subject were scanned and analyzed with the use of WinCeph version 11.0 software package. Descriptive statistics (mean and standard deviation) were calculated for all measured variables. Independent t-tests were performed to assess the intergender differences. Results: Cephalometric angular measurements remain largely constant, whereas most cephalometric linear measurements change with advancing age, such as anterior facial height (N-Ans, Ans-Me), hard palatal length (Ans-Pns) mandibular ramus height (Cd-Go), mandibular body length (Cd-Gn) were increasing significantly by dental age in both gender. Gender differences were not statistically significant for any of the angular measurement at ages studied, but linear measurements of male subjects had larger average values than female subjects. Conclusion: Our results showed that linear cephalometric dimension of the hard tissue was gender-dependent. Therefore, gender-specific differences of craniofacial distances should be taken into account during diagnosis and treatment planning. The results from this study can be used as reference values for 6-15 years old children of Mongolia.