3D Cephalometric Analysis Research Articles

Novel method of constructing a stable reference frame for 3-dimensional cephalometric analysis.

Three-dimensional (3D) cephalometric analysis has provided the ability to overcome the limitations of 2-dimensional cephalometrics. However, there is no international standard method for 3D cephalometric analysis yet. Determining the position of the midsagittal plane (MSP) practically is the most important step when constructing a 3D cephalometric reference frame. Recent studies have used several approaches to construct the MSP. In this study, we aimed to determine the true MSP of the skull to establish a stable reference frame for 3D cephalometric analysis. Cone-beam computed tomography data of 12 adult patients were divided into 2 groups: symmetry (n=6) and asymmetry (n=6). The anterior cranial base region model and its mirror model were registered and used to determine the MSP to prevent any influence of the degree of symmetry on the registration of other parts of the skull, particularly for subjects with severe facial or cranial asymmetry. Intraclass correlation coefficients were used to assess intraexaminer and interexaminer reliabilities of the x, y, and z coordinates of all landmarks measured by 2 investigators. The intraclass correlation coefficient values were greater than 0.9, indicating almost perfect agreement. The candidate reference planes constructed using this novel method were thought to be reliable for 3D cephalometric analysis and may expand its clinical applicability in patients with cranial asymmetry.

3D cephalometric analysis using Magnetic Resonance Imaging: validation of accuracy and reproducibility

The aim of this study was to validate geometric accuracy and in vivo reproducibility of landmark-based cephalometric measurements using high-resolution 3D Magnetic Resonance Imaging (MRI) at 3 Tesla. For accuracy validation, 96 angular and 96 linear measurements were taken on a phantom in 3 different positions. In vivo MRI scans were performed on 3 volunteers in five head positions. For each in vivo scan, 27 landmarks were determined from which 19 angles and 26 distances were calculated. Statistical analysis was performed using Bland-Altman analysis, the two one-sided tests procedure and repeated measures one-way analysis of variance. In comparison to ground truth, all MRI-based phantom measurements showed statistical equivalence (p < 0.001) and an excellent agreement in Bland-Altman analysis (bias ranges: −0.090–0.044°, −0.220–0.241 mm). In vivo cephalometric analysis was highly reproducible among the five different head positions in all study participants, without statistical differences for all angles and distances (p > 0.05). Ranges between maximum and minimum in vivo values were consistently smaller than 2° and 2 mm, respectively (average ranges: 0.88°/0.87 mm). In conclusion, this study demonstrates that accurate and reproducible 3D cephalometric analysis can be performed without exposure to ionizing radiation using MRI.

Three-dimensional analysis of airway space and mandibular morphology in Pierre Robin sequence using cone beam computed tomography.

Objectives: The Pierre Robin sequence (PRS) is defined by retromicrognathia, glossoptosis, and sleep apnea and can also be associated with cleft palate. Diagnosis, management and mandibular catch-up growth are still controversial issues in PRS patients. The aim of our retrospective study was to evaluate in three dimensions (3D) the airway space and mandibular morphology in PRS compared to a normal control group patients in the pre-orthodontic period of life. The null hypothesis was that we would not find a significant difference between the PRS and control group patients in oropharyngeal airway volume measurements. Material and methods: We analyzed 9 PRS patients (mean age: 8 years-old) who underwent cleft palate surgery in the first four months of life, performed by the same surgeon using the same technique. Cone-beam computed tomography (CBCT) was performed in these patients after local ethical committee approval. The control group consisted of 15 patients (mean age: 9 years-old) with CBCT already performed for other reasons. 3D Slicer was used in both groups for semi-automatic segmentation of the airway space. Two independent observers performed semi-automatic segmentations twice in each patient with a one- week interval between the two series of measurements. Airway volume was automatically measured using 3D Slicer. We also developed a 3D cephalometric analysis with Maxilim software in order to define a 3D mandibular morphology which consisted of 25 landmarks, 4 planes, and 23 distances. Two independent observers performed the 3D cephalometric analysis twice for each patient, with a one- week interval between the two series of measurements. Results: There was no significant difference in the intra- and inter-observer measurements between the PRS and control groups for airway space volume (p&lt;0.05). However, there was a significant difference in the shape of the mandible between the PRS group and the control group (p&lt;0.05). Conclusions: Vertical ramus width and mandibular global anteroposterior length were significantly lower in the PRS group. Mandibular hypoplasia could be found in PRS patients not only in the horizontal dimension. Nemesis relevance: the null hypothesis was confirmed. Moreover we failed to find exactly the same control group under 9 years-old due to radioprotection restrictions of application of cone beam CT in children.

Three-dimensional evaluation of mandibular asymmetry: a new classification and three-dimensional cephalometric analysis

Mandibular asymmetry is common among orthognathic patients and exhibits great variation. The aim of this study was to propose a new classification of mandibular asymmetry by anatomical regions; namely R (ramus), B (mandibular body) and C (chin), in conjunction with a corresponding ‘RBC’ three-dimensional (3D) cephalometric analysis. The cone beam computed tomography data of 65 patients with mandibular asymmetry was retrieved to perform the RBC 3D cephalometric analysis and to investigate the characteristics of mandibular asymmetry. It was found that the more posteriorly in mandible, the more pronounced was the vertical asymmetry. Significant transverse asymmetry was only noted in mandibular body. Both mandibular body and chin were significantly asymmetric in length. Seven significant morphologic predictors of menton deviation were identified, namely lower dental midline shift, difference in ramus height, difference in chin length, difference in body length, body height on contralateral side, coronoid height on deviated side and body width on contralateral side, confirming the complex nature of mandibular asymmetry. This simple and concise classification allows comprehensive assessment of mandible morphology by anatomical regions which also facilitates diagnosis, treatment planning and communication in both clinical and research settings.

A new methodology for automatic detection of reference points in 3D cephalometry: A pilot study

The aim of this study was to develop a new method for an automatic detection of reference points in 3D cephalometry to overcome the limits of 2D cephalometric analyses. A specific application was designed using the C++ language for automatic and manual identification of 21 (reference) points on the craniofacial structures. Our algorithm is based on the implementation of an anatomical and geometrical network adapted to the craniofacial structure. This network was constructed based on the anatomical knowledge of the 3D cephalometric (reference) points. The proposed algorithm was tested on five CBCT images. The proposed approach for the automatic 3D cephalometric identification was able to detect 21 points with a mean error of 2.32mm. In this pilot study, we propose an automated methodology for the identification of the 3D cephalometric (reference) points. A larger sample will be implemented in the future to assess the method validity and reliability.

Automatic 3-dimensional cephalometric landmarking based on active shape models in related projections.

This article presents a novel technique for automatic cephalometric landmark localization on 3-dimensional (3D) cone-beam computed tomography (CBCT) volumes by using an active shape model to search for landmarks in related projections. Twenty-four random CBCT scans from a public data set were imported and processed into Matlab (MathWorks, Natick, Mass). Orthogonal coronal and sagittal projections (digitally reconstructed radiographs) were created, and 2 trained active shape models were used to locate cephalometric landmarks on each. Finally, by relating projections, 18 tridimensional landmarks were located on CBCT volume representations. From our 3D gold standard, a 3.64-mm mean error in localization of cephalometric landmarks was achieved with this method, with the highest localization errors in the porion and sella regions because of the low volume definition. The proposed algorithm for automatic 3D landmarking on CBCT volumes seems to be useful for 3D cephalometric analysis. This study shows that a fast 2-dimensional landmark search can be useful for 3D localization, which could save computational time compared with a full-volume analysis. Also, this research confirmsthat by using CBCT for cephalometry, there are no distortion projections, and full structure information of a virtual patient is manageable in a personal computer.

Three dimensional reliability analyses of currently used methods for assessment of sagittal jaw discrepancy.

BackgroundThe objective of this study was to analyse three dimensionally the reliability and correlation of angular and linear measurements in assessment of anteroposterior skeletal discrepancy.Material and MethodsIn this retrospective cross sectional study, a sample of 213 subjects were three-dimensionally analysed from cone-beam computed tomography scans. The sample was divided according to three dimensional measurement of anteroposterior relation (ANB angle) into three groups (skeletal Class I, Class II and Class III). The anterior-posterior cephalometric indicators were measured on volumetric images using Anatomage software (InVivo5.2). These measurements included three angular and seven linear measurements. Cross tabulations were performed to correlate the ANB angle with each method. Intra-class Correlation Coefficient (ICC) test was applied for the difference between the two reliability measurements. P value of < 0.05 was considered significant.ResultsThere was a statistically significant (P<0.05) agreement between all methods used with variability in assessment of different anteroposterior relations. The highest correlation was between ANB and DSOJ (0.913), strong correlation with AB/FH, AB/SN/, MM bisector, AB/PP, Wits appraisal (0.896, 0.890, 0.878, 0.867,and 0.858, respectively), moderate with AD/SN and Beta angle (0.787 and 0.760), and weak correlation with corrected ANB angle (0.550).ConclusionsConjunctive usage of ANB angle with DSOJ, AB/FH, AB/SN/, MM bisector, AB/PP and Wits appraisal in 3D cephalometric analysis provide a more reliable and valid indicator of the skeletal anteroposterior relationship. Clinical relevance: Most of orthodontic literature depends on single method (ANB) with its drawbacks in assessment of skeletal discrepancy which is a cardinal factors for proper treatment planning, this study assessed three dimensionally the degree of correlation between all available methods to make clinical judgement more accurate based on more than one method of assessment. Key words:Anteroposterior relationships, ANB angle, Three-dimension, CBCT.

A THREE-DIMENSIONAL EVALUATION OF THE EFFECTS OF DIFFERENT INCISOR INTRUSION MECHANICS TO THE PERMANENT MAXILLARY FIRST MOLAR TEETH BY USING CONE BEAM COMPUTED TOMOGRAPHY

Objective: The present study aims to evaluate the impacts of the upper incisor teeth intrusion in deepbite patients by two different techniques to the permanent maxillary first molar tooth using the three-dimensional cephalometric analysis in the individuals. Materials and Methods: The population of this study consists of 34 patients with >4 mm overbite and a ≥2 mm gummy smile during post-pubertal period. Patients who underwent intrusion of upper incisor teeth were randomized to receive Connecticut intrusion arch (CTA) or miniscrew anchorage intrusion system (MAIS) to compare the impacts on permanent maxillary first molar teeth. Cone Beam Computed Tomography (CBCT) data obtained before (T1) and after (T2) intrusion were evaluated through three-dimensional (3D) cephalometric analysis. Intragroup assessment of treatment-related variables were performed via “t-test in dependent samples” and intergroup comparisons were assessed by “t-test in independent samples”. Results: In patients who underwent intrusion of upper incisors, permanent maxillary first molar teeth became deviated distally (1.48 mm/7.63 degree) only in CTA group, a statistically significant difference was found between two groups (p<0.05). The distance between resistance centers of maxillary first molar teeth was only increased in CTA group (0.31 mm), which also statistically differed from MAIS group. Conclusion: CTA and MAIS techniques resulted in similar intrusive effects overall at the end of the treatment. While MAIS is recommended when anchorage from posterior region is not desired in patients with deep overbite, we believe that CTA may serve a suitable treatment alternative where miniscrew technique could not be performed.

Three-dimensional analysis of condylar remodeling and skeletal relapse following bimaxillary surgery: A 2-year follow-up study

PurposeTo quantify the postoperative condylar remodelling and its role in skeletal relapse after bimaxillary surgery. Materials and methods50 patients with mandibular hypoplasia who underwent bimaxillary surgery were analyzed. CBCT scans were acquired preoperatively, one week postoperatively and two years postoperatively. 3D cephalometric analysis was carried out for each CBCT scan, after which the condylar volume analysis was performed. ResultsThe maxilla was advanced by a mean of 2.1 mm with a corresponding mean relapse of 0.3 mm. The maxilla was impacted in 23 and extruded in 27 patients. The mean mandibular advancement was 7.8 mm. Two years after surgery a mean mandibular skeletal relapse of 1.3 mm was observed. 78% of condyles exhibited a postoperative reduction in volume of 179 mm3 (mean), equivalent to 12.5 volume%. Postoperative condylar volume loss was correlated with mandibular skeletal relapse (r = 0.42, p < 0.01), but not with maxilla relapse. Linear regression analysis identified age, gender, amount of surgical mandibular advancement and postoperative condylar volume loss as predictive factors for mandibular relapse. ConclusionA significant correlation between postoperative condylar volume loss and skeletal relapse was found. Young female patients who underwent large bimaxillary advancement and postoperative reduction in condylar volume were particularly at risk for skeletal relapse.

Three-dimensional morphological characterization of malocclusions with mandibular lateral displacement using cone-beam computed tomography

Objective: The purpose of this study was to evaluate the morphologic characteristics of MLD malocclusions using 3D imaging.Materials and methods: MLD characteristics were examined using CBCT data in 40 subjects. A 3D Cephalometric analysis was developed to describe the spatial position of the mandible and temporal bones.Results: Vertical dental heights were shorter and the posterior occlusal plane (POP) presented a steeper sagittal inclination on the shifted side (the side of the laterally displaced bony chin) than on the contralateral side. (p < 0.01). The MLD was related to a superiorly inclined POP Cant in the same direction (r = 0.82; p < 0.01). The shifted side condyle was dislocated medially and was smaller. Temporal bone sagittal inclination showed a more forward and medial inclination on the contralateral side (p < 0.01).Conclusions: A unilateral decrease in the vertical height of the dentition and the subsequent steeper occlusal plane inclinations correlated with (1) mandibular rotational displacement and condylar lateral displacement, (2) mandibular and condylar morphologic changes (3) changes in temporal bone position.

Digital workflow in orthognathic surgery

This is to share our eight years experience in gradually adopting, modifying and improving the digital workflow in orthognathic workup for our patients in a private maxillofacial surgical centre. Cone-beam computed tomography gives three-dimensional (3D) information about the skeletal and dental tissue. Combining the scanned dental casts using laser or optical scanner augments the accuracy at the occlusal level. This has been recently replaced by using intraoral scanner directly. The surface texture of the soft tissue mask is further improved by fusing with image taken by 3D photogrammetry. The combined result is a digital copy of our patient. We can perform 3D cephalometric analysis to quantify the deformity. Different commercially available software have been tried to do the virtual surgical planning. Digital wafers can be designed and produced by 3D printing for transferring of our surgical plan to the operating theatre. Similarly cutting templates can also be fabricated. Physical models of the preoperative or operated facial skeleton can be produced if necessary for better communication. Soft tissue simulation helps our patients to understand the effect of our surgical movements on their appearance besides the change in their occlusion. Clinical audit of the surgical outcome comparing with the surgical plan and the monitoring of the stability of the surgery can be achieved in a more comprehensive way using 3D data. The digital workflow also facilitates multidisciplinary collaboration in providing better and more predictable outcome for our patients.

Reproducibility of three-dimensional posterior cranial base angles using low-dose computed tomography.

One of the key aspects of three-dimensional (3D) craniofacial cephalometry is the measurement of posterior cranial base angle as this area is deeply involved in craniofacial development. The purpose of our retrospective study was to define the best reproducible 3D posterior cranial base angles among five 3D angles transposed from 2D cephalometry (Cousin, BL1 of Ross and Ravosa, Bjork, Delaire, CBA4 of Liberman) and seven 3D angles based on physical anthropology studies and on new concepts (R1 to R7). The null hypothesis was that all 3D posterior cranial base angles were equally reproducible. We used a preoperative low-dose computed tomography (CT) data from 20 adult patients undergoing orthognathic surgery after approval by local ethical committee. Two independent observers performed two series of 23 3D landmark identifications on 3D CT surface rendering of each patient using Maxilim software. Then, the same observers performed twice 3D cephalometric analyses (23 landmarks, 4 midpoints, 19 planes) that provided the automatic measurement of 12 posterior cranial base angles. Inter-observer correlation coefficient varied from 0.545 (Cousin) to 0.695 (CBA4 of Liberman) and from -0.177 (R2) to 0.827 (R4). The null hypothesis was rejected. The most reproducible angle was 3D angle R4 based on "basion," "superior optic" (right, left), and "crista galli inferior" landmarks. R4 angle might be used as reference 3D posterior cranial base angle in further clinical studies involving 3D cephalometry as a diagnostic tool for orthodontics and for orthognathic surgery.

Computer-aided cephalometric landmark annotation for CBCT data.

Nowadays, with the increased diffusion of Cone Beam Computerized Tomography (CBCT) scanners in dental and maxillo-facial practice, 3D cephalometric analysis is emerging. Maxillofacial surgeons and dentists make wide use of cephalometric analysis in diagnosis, surgery and treatment planning. Accuracy and repeatability of the manual approach, the most common approach in clinical practice, are limited by intra- and inter-subject variability in landmark identification. So, we propose a computer-aided landmark annotation approach that estimates the three-dimensional (3D) positions of 21 selected landmarks. The procedure involves an adaptive cluster-based segmentation of bone tissues followed by an intensity-based registration of an annotated reference volume onto a patient Cone Beam CT (CBCT) head volume. The outcomes of the annotation process are presented to the clinician as a 3D surface of the patient skull with the estimate landmark displayed on it. Moreover, each landmark is centered into a spherical confidence region that can help the clinician in a subsequent manual refinement of the annotation. The algorithm was validated onto 18 CBCT images. Automatic segmentation shows a high accuracy level with no significant difference between automatically and manually determined threshold values. The overall median value of the localization error was equal to 1.99 mm with an interquartile range (IQR) of 1.22-2.89 mm. The obtained results are promising, segmentation was proved to be very robust and the achieved accuracy level in landmark annotation was acceptable for most of landmarks and comparable with other available methods.

Three-dimensional virtual simulation of alar width changes following bimaxillary osteotomies

The aim of this study was to evaluate the accuracy of three-dimensional (3D) soft tissue simulation of nose width changes following bimaxillary osteotomies and to identify patient- and surgery-related factors that may affect the accuracy of simulation. Sixty patients (mean age 26 years) who underwent bimaxillary osteotomies participated in this study. Cone beam computed tomography scans were acquired preoperatively and at 1-year postoperative. The 3D hard and soft tissue rendered preoperative and postoperative virtual head models were superimposed, after which the maxilla and mandible were segmented and aligned to the postoperative position. The postoperative changes in alar width were simulated using a mass tensor model (MTM)-based algorithm and compared with the postoperative outcome. 3D cephalometric analyses were used to quantify the simulation error. The postoperative alar width was increased by 1.6±1.1mm and the mean error between the 3D simulation and the actual postoperative alar width was 1.0±0.9mm. The predictability was not correlated to factors such as age, sex, alar cinch suture, VY closure, maxillary advancement, or a history of surgically assisted rapid maxillary expansion. The MTM-based simulation model of postoperative alar width change was found to be reasonably accurate, although there is room for further improvement.

Cephalometric Angular Measurements of the Mandible Using Three-Dimensional Computed Tomography Scans in Koreans.

We conducted this study to analyze the values of the key cephalometric angular measurements of the mandible using 3-dimensional (3D) computed tomography scans. In the 106 enrolled patients, a 3D cephalometric analysis was performed to measure the angular variables of the mandible. These values were compared between the two sides and between the two sexes. The frontal measurements revealed that the mandibular body curve angle was larger on the left (Lt) side (right [Rt], 141.24±7.54; Lt, 142.68±6.94; P=0.002) and the gonial angle was larger on the right side (Rt, 134.37±8.44; Lt, 131.54±7.14; P<0.001). The sagittal measurements showed that the gonial angle was larger on the right side (Rt, 134.37±8.44; Lt, 131.54±7.14; P>0.05). Further, the transverse measurements revealed that the mandibular body curve angle was larger on the right side (Rt, 140.28±7.05; Lt, 137.56±6.23; P<0.001). These results provide an average of the mandibular angular measurements for the Korean population, establishing a standard for determining surgical patient groups and outcome evaluations in the field of mandible contour surgery.

Discussion: Cephalometric Angular Measurements of the Mandible Using Three-Dimensional Computed Tomography Scans in Koreans

BackgroundWe conducted this study to analyze the values of the key cephalometric angular measurements of the mandible using 3-dimensional (3D) computed tomography scans.MethodsIn the 106 enrolled patients, a 3D cephalometric analysis was performed to measure the angular variables of the mandible. These values were compared between the two sides and between the two sexes.ResultsThe frontal measurements revealed that the mandibular body curve angle was larger on the left (Lt) side (right [Rt], 141.24±7.54; Lt, 142.68±6.94; P=0.002) and the gonial angle was larger on the right side (Rt, 134.37±8.44; Lt, 131.54±7.14; P<0.001). The sagittal measurements showed that the gonial angle was larger on the right side (Rt, 134.37±8.44; Lt, 131.54±7.14; P>0.05). Further, the transverse measurements revealed that the mandibular body curve angle was larger on the right side (Rt, 140.28±7.05; Lt, 137.56±6.23; P<0.001).ConclusionsThese results provide an average of the mandibular angular measurements for the Korean population, establishing a standard for determining surgical patient groups and outcome evaluations in the field of mandible contour surgery.

Algorithm for planning a double-jaw orthognathic surgery using a computer-aided surgical simulation (CASS) protocol. Part 2: three-dimensional cephalometry

Three-dimensional (3D) cephalometry is not as simple as just adding a ‘third’ dimension to a traditional two-dimensional cephalometric analysis. There are more complex issues in 3D analysis. These include how reference frames are created, how size, position, orientation and shape are measured, and how symmetry is assessed. The main purpose of this article is to present the geometric principles of 3D cephalometry. In addition, the Gateno–Xia cephalometric analysis is presented; this is the first 3D cephalometric analysis to observe these principles.

Multidimensional esthetic evaluation of patients with a cleft lip and palate wearing a maxillary partial removable dental prosthesis: A 5-year retrospective study

Statement of problemNo published quantitative or qualitative studies are available of the 2-dimensional (2D) and 3D esthetic evaluation of patients with a cleft lip and palate (CLP) wearing a maxillary partial removable dental prosthesis (MPRDP). PurposeThe purpose of this retrospective clinical study was to qualitatively and quantitatively evaluate the facial esthetic improvements of patients with CLP wearing an MPRDP for 5 years by using 2D cephalometric and 3D photogrammetry methods. Material and methodsSix patients, 2 men and 4 women, with CLP deformity were recruited and treated with an MPRDP by the same dentist over 5 years. Results of the clinical examination were recorded before and after wearing the MPRDP. Sella-nasion-A (SNA) point, the U1-SN, 0-meridian to SN, nasolabial angle, and maxillary incisor exposure were measured by 2D cephalometric analysis before and after wearing the MPRDP. 3D photographs were captured by 3dMD software. Geomagic Spark Studio software was also used to measure the patients’ improved upper lip projection after the MPRDP was worn. The paired sample t test was used to compare the participants (α=.05). ResultsU1-SN (P<.05) and 0-meridian to SN (P<.01) had significant deviation statistically. After patients underwent clinical examination, SNA and nasiolabial angles were found to have improved, although no statistical significance was observed. ConclusionsA maxillary partial removable dental prosthesis (MPRDP) can advance the upper lip forward, restoring the subnasal and upper lip projection. Patients’ nasiolabial angles with MPRDPs were decreased, which led to a more harmonious facial contour.

Qualitative and quantitative evaluation of central incisor movement by integration of three-dimensional images of dental cast and cephalogram

PurposeThe present study aimed to establish a method for qualitatively and quantitatively determining tooth movement by integrating three-dimensional (3D) model analysis and cephalometric analysis. Materials and methodsSuperimposition of 3D images of dental casts before and after orthodontic treatment was performed in two steps. First, initial and final 3D images of dental casts were superimposed at the central incisor and then the reference axis of the incisor was constructed. Second, another superimposition was carried out at the medial points of the third palatal rugae and the palatal vault. The changes in the inclination of the central incisor were measured using an established method of 3D model analysis and cephalometric analysis. The error of measurement in 3D model analysis was compared with that in cephalometric analysis. ResultsThere was no significant difference in the degree of incisor tipping between times (Time 1 and Time 2) for cephalometric analysis and 3D model analysis, and between the averaged (Time 1 and Time 2) measurements from cephalogram and the 3D model. The error of measurement for 3D model analysis was 0.58°, and the 95% confidence interval (CI) was [−0.62, 0.62]. Corresponding values for cephalometric analysis were 2.02° and [−1.49, 2.73], respectively. ConclusionThe 3D model superimposition method established in the present study was found to be reliable enough to determine the degree of tipping and the location of the center of rotation of the incisor before and after orthodontic treatment.

Comparative study between cone-beam and digital lateral head film cephalometric measurements

Objective: The objective of the present study was to determine the differences between cephalometric measurements obtained by two different methods: cone-beam tomography and digital lateral head film. Material and methods: Measurements were performed (anterior facial height, mandibular length, upper incisor to the A-Pog line, lower incisor to the A-Pog line, ANS-PNS, ANB angle) on 30 patients by means of lateral digital radiography and cone-beam. The statistic test used was the t-Student. Results: The measurement that presented a statistically significant difference was the mandibular length (p = 0.001). Conclusion: Measurements performed in cone-beam scans for a 3D cephalometric analysis did not show evidence of being more effective or reliable in comparison with measurements performed in 2D. Key words: Cone-beam, lateral head film, cephalometry, reliability.