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Objectives To investigate the association between three-dimensional (3D) skeletal variables and self-recognition of facial asymmetry in skeletal Class III patients. Materials and Methods Questionnaires and cone beam computed tomography of 74 patients (42 men and 32 women; mean age: 22.8 ± 4.5 years) with skeletal Class III and facial asymmetry were collected retrospectively. Patients were classified into three groups: group Sy (recognition of symmetry), group NS (not sure), and group Asy (recognition of asymmetry), according to their responses to the questionnaires. To assess 3D anatomic differences in the maxillomandibular region, six 3D hard tissue variables: maxillary height, ramal length, frontal ramal inclination (FRI), lateral ramal inclination (LRI), mandibular body length (Mn BL), and mandibular body height (Mn BH) were compared among the three self-recognition groups. Six 3D hard tissue variables and Menton deviation were reduced into three factors and their association with the self-recognition of facial asymmetry was investigated. Results Maxillary height, FRI, LRI, Mn BH, and Menton deviation demonstrated significant differences among the three self-recognition groups. The reduced factors, which consisted of transverse and vertical parameters, and vertical parameter of the mandibular corpus, demonstrated significant differences among the three self-recognition groups. The difference in Mn BH influenced the self-recognition of facial asymmetry. Conclusions Both the transverse and vertical parameter of the skeleton were determinant in self-recognition of facial asymmetry. Identification of the skeletal difference in the lateral view involving LRI and Mn BH should be included for assessment of facial asymmetry.

Purpose The purpose of this study was to evaluate the accuracy of virtual 3-dimensional (3D) cephalograms constructed using the principle of biplanar radiography by comparing them with cone-beam computed tomography(CBCT) images. Materials and Methods Thirty orthodontic patients were enrolled in this study. Frontal and lateral cephalograms were obtained with the use of a head posture aligner and reconstructed into 3D cephalograms using biplanar radiography software. Thirty-four measurements representing the height, width, depth, and oblique distance were computed in 3 dimensions, and compared with the measurements from the 3D images obtained by CBCT, using the paired t-test and Bland-Altman analysis. Results Comparison of height, width, depth, and oblique measurements showed no statistically significant differences between the measurements obtained from 3D cephalograms and those from CBCT images (P>0.05). Bland-Altman plots also showed high agreement between the 3D cephalograms and CBCT images. Conclusion Accurate 3D cephalograms can be constructed using the principle of biplanar radiography if frontal and lateral cephalograms can be obtained with a head posture aligner. Three-dimensional cephalograms generated using biplanar radiography can replace CBCT images taken for diagnostic purposes.

The aim of this study was to compare how the displacement of the mandibular condyle changed after symmetric or asymmetric mandibular setback surgery using the surgery-first approach (SFA). Patients who underwent mandibular setback surgery using the SFA were selected and divided into a symmetry group (n = 18) with differences of less than 2 mm between the right and left setback, and an asymmetry group (n = 18) with a difference of greater than 2 mm. Cone-beam computed tomography (CBCT)-generated cephalograms were obtained after three-dimensional superimposition of CBCT images taken before surgery (T0), within one week after surgery (T1), and seven months after surgery (T2). The condylar positions were measured. Condylar positional changes according to time were compared between the two groups and correlation analysis was performed. There were significant positional changes in mandibular condyles over time in both groups. However, most of these changes returned to their initial state. In the asymmetry group, there was a greater internal rotation of the mandibular condyle on the lesser setback side. The correlation analysis results revealed that only the setback difference was associated with rotational displacement of the condyle on the lesser setback side at two time points (T1-T0, T2-T0). In the SFA, significant condylar displacement occurred immediately after both symmetric and asymmetric mandibular setback surgery, and the right/left difference in mandibular setback showed a significant positive correlation with rotational displacement. Although more significant rotational displacement of the mandibular condyle was observed after asymmetric mandibular setback surgery, the amount was not large enough to be clinically significant.

This research aimed to compare the estimation error of the root axis using 3-dimensional (3D) tooth models at the midtreatment stage between the whole-surface scan (WSS) and lingual-surface scan (LSS) methods.The sample consisted of 208 teeth (26 each of central incisors, canines, second premolars, and first molars in the maxillary and mandibular dentition) from 13 patients whose pre- and midtreatment intraoral scan and cone-beam computed tomography (CBCT) were available. The 3D tooth models were constructed by merging the intraoral-scan crowns and the CBCT-scan roots obtained at the pretreatment stage. To estimate the root axis at the midtreatment stage, we superimposed the individual 3D tooth models onto the midtreatment intraoral scan obtained by the WSS and LSS methods. The midtreatment CBCT scan was used as the gold standard to determine the real root axis. The estimated root axis in terms of mesiodistal angulation and buccolingual inclination was measured in the WSS and LSS methods, and statistical analysis was performed.The estimation errors of the mesiodistal angulation and buccolingual inclination were 2.0° in both methods. The LSS method demonstrated a statistically larger but clinically insignificant estimation error than the WSS method in the mandibular canine (mesiodistal angulation, 1.95° vs 1.62°) and the total tested teeth (mesiodistal angulation, 1.40° vs 1.29°; buccolingual inclination, 1.51° vs 1.41°).Because the estimation errors of the root axis angle using the 3D tooth model by the WSS and LSS methods were within the clinically acceptable range, the root axis can be estimated by both methods.

Objective To evaluate the construction reproducibility of a composite tooth model (CTM) composed of an intraoral-scanned crown and a cone-beam computed tomography (CBCT)-scanned root. Methods The study assessed 240 teeth (30 central incisors, 30 canines, 30 second premolars, and 30 first molars in the maxillary and mandibular arches) from 15 young adult patients whose pre-treatment intraoral scan and CBCT were available. Examiner-Reference (3 years' experience in CTM construction) and Examiners-A and Examiner-B (no experience) constructed the individual CTMs independently by performing the following steps: image acquisition and processing into a three-dimensional model, integration of intraoral-scanned crowns and CBCT-scanned teeth, and replacement of the CBCT-scanned crown with the intraoral-scanned crown. The tooth axis angle in terms of mesiodistal angulation and buccolingual inclination of the CTMs constructed by the three examiners were measured. To assess the construction reproducibility of CTMs, intraclass correlation coefficient (ICC) assessments were performed. Results The ICC values of mesiodistal angulation and buccolingual inclination among the 3 examiners showed excellent agreement (0.950-0.992 and 0.965-0.993; 0.976-0.994 and 0.973-0.995 in the maxillary and mandibular arches, respectively). Conclusions The CTM showed excellent construction reproducibility in mesiodistal angulation and buccolingual inclination regardless of the construction skill and experience levels of the examiners.

The purpose of this study was to investigate the registration accuracy between intraoral-scanned crowns and cone-beam computed tomography (CBCT)-scanned crowns in various registration methods.The samples consisted of 18 Korean adult patients, whose pretreatment intraoral scans and CBCT images were available. A 3-dimensional (3D) dental model was fabricated using a TRIOS intraoral scanner (3Shape, Copenhagen, Denmark) and the OrthoAnalyzer program (version 1.7.1.4; 3Shape). After the CBCT image was taken, 3D volume rendering was performed to fabricate a 3D dental model using InVivo5 software (version 5.1; Anatomage, San Jose, Calif). Registration of the 3D dental crowns made from intraoral- and CBCT-scanned images was performed with Rapidform 2006 software (Inus Technology, Seoul, Korea) by a single operator. According to registration methods, 3 groups were established: individual-arch-total-registration group, individual-arch-segment-registration group, and bimaxillary-arch-centric-occlusion-registration group (n = 18 per group). After the amounts of shell/shell deviation were obtained, the mixed model analysis of variance and Bonferroni correction were performed.Although there was no significant difference in the registration accuracy between the individual-arch-total-registration group and individual-arch-segment-registration group, the bimaxillary-arch-centric-occlusion-registration group exhibited the lowest registration accuracy (maxillary and mandibular teeth, all 0.21 mm in the individual-arch-total-registration group; all 0.20 mm in the individual-arch-segment-registration group vs 0.26 mm and 0.25 mm in the bimaxillary-arch-centric-occlusion-registration group; P 0.001). Color-coded visualization charts exhibited that most red spots were localized on the occlusal surface of the posterior teeth in all 3 groups.When considering the registration accuracy and convenience of the process, the individual-arch-total-registration method can be regarded as an efficient tool when integrating CBCT-scanned crown and intraoral-scanned crown.

Objective This study aimed to evaluate the accuracy of deep learning-based integrated tooth models (ITMs) by merging intraoral scans and cone-beam computed tomography (CBCT) scans for three-dimensional (3D) evaluation of root position during orthodontic treatment and to compare the fabrication process of integrated tooth models (ITMs) with manual method. Material and methods Intraoral scans and corresponding CBCT scans before and after treatment were obtained from 15 patients who completed orthodontic treatment with premolar extraction. A total of 600 ITMs were generated using deep learning technology and manual methods by merging the intraoral scans and CBCT scans at pretreatment. Posttreatment intraoral scans were integrated into the tooth model, and the resulting estimated root positions were compared with the actual root position at posttreatment CBCT. Discrepancies between the estimated and actual root position including average surface differences, arch widths, inter-root distances, and root axis angles were obtained in both the deep learning and manual method, and these measurements were compared between the two methods. Results The average surface differences of estimated and actual ITMs in the manual method were 0.02 mm and 0.03 mm for the maxillary and mandibular arches, respectively. In the deep learning method, the discrepancies were 0.07 mm and 0.08 mm for the maxillary and mandibular arches, respectively. For the measurements of arch widths, inter-root distances, and root axis angles, there were no significant differences between estimated and actual models both in the manual and in the deep learning methods, except for some measurements. Comparing the two methods, only three measurements showed significant differences. The procedure times taken to obtain the measurements were longer in the manual method than in the deep learning method. Conclusion Both deep learning and manual methods showed similar accuracy in the integration of intraoral scans and CBCT images. Considering time and efficiency, the deep learning automatic method for ITMs is highly recommended for clinical practice.

Objective This in-vivo study aimed to compare landmark identification errors in anteroposterior (AP) and posteroanterior (PA) cephalograms generated from cone-beam computed tomography (CBCT) scan data in order to examine the feasibility of using AP cephalograms in clinical settings. Methods AP and PA cephalograms were generated from CBCT scans obtained from 25 adults. Four experienced and four inexperienced examiners were selected depending on their experience levels in analyzing frontal cephalograms. They identified six cephalometric landmarks on AP and PA cephalograms. The errors incurred in positioning the cephalometric landmarks on the AP and PA cephalograms were calculated by using the straight-line distance and the horizontal and vertical components as parameters. Results Comparison of the landmark identification errors in CBCT-generated frontal cephalograms revealed that landmark-dependent differences were greater than experience- or projection-dependent differences. Comparisons of landmark identification errors in the horizontal and vertical directions revealed larger errors in identification of the crista galli and anterior nasal spine in the vertical direction and the menton in the horizontal direction, in comparison with the other landmarks. Comparison of landmark identification errors between the AP and PA projections in CBCT-generated images revealed a slightly higher error rate in the AP projections, with no inter-examiner differences. Statistical testing of the differences in landmark identification errors between AP and PA cephalograms showed no statistically significant differences for all landmarks. Conclusions The reproducibility of CBCT-generated AP cephalograms is comparable to that of PA cephalograms; therefore, AP cephalograms can be generated reliably from CBCT scan data in clinical settings.

Objective Precise identification of landmarks on posteroanterior (PA) cephalograms is necessary when evaluating lateral problems such as facial asymmetry. The aim of the present study was to investigate whether the use of lateral (LA) cephalograms can reduce errors in landmark identification on PA cephalograms. Methods Five examiners identified 16 landmarks (Cg, N, ANS, GT, Me, RO, Lo, FM, Z, Or, Zyg, Cd, NC, Ms, M, and Ag) on 32 PA cephalograms with and without LA cephalograms at the same time. The positions of the landmarks were recorded and saved in the horizontal and vertical direction. The mean errors and standard deviation of landmarks location according to the use of LA cephalograms were compared for each landmark. Results Relatively small errors were found for ANS, Me, Ms, and Ag, while relatively large errors were found for N, GT, Z, Or, and Cd. No significant difference was found between the horizontal and vertical errors for Z and Or, while large vertical errors were found for N, GT, and Cd. The value of identification error was lower when the landmarks were identified using LA cephalograms. Statistically significant error reductions were found at N and Cd with LA cephalograms, especially in the vertical direction. Conclusions The use of LA cephalograms during identification of landmarks on PA cephalograms could help reduce identification errors.

Background and Overview Ectopic eruption of permanent molars is one of the challenges that arise in the early mixed dentition period, particularly when the root of the primary second molar is resorbed due to mesial angulation of the impacted first molar. The authors introduce a simple and efficient method to unlock ectopically erupting first molars using a light wire. Case Description The authors describe the cases of 2 girls (8 and 7 years old) who sought treatment for locking of their maxillary and mandibular first molars, respectively. A 0.012-inch nickel titanium wire was compressed and bonded to the first molars and primary second molars to unlock the first molars. The primary second molars were splinted to the adjacent primary first molars and canines using bonded multistranded wires. As the compressed wires straightened over time, the locked first molars were tipped back without any substantial mesial movement of the primary teeth. After unlocking the molars, the nickel titanium wires were removed to allow spontaneous eruption of the first molars. Conclusions and Practical Implications Although the primary molar roots were considerably resorbed, the ectopically erupting first molars were unlocked successfully without any substantial movement of the primary teeth. The clinical procedure was simple, and no laboratory procedures were needed. In addition, the anchorage burden was reduced with the use of light forces. The authors suggest that primary second molars with substantial root resorption due to ectopic eruption of permanent first molars can be saved simply and efficiently.

Objective The aim of this study was to examine whether integration accuracy increases upon removing artifacts from the registration area when integrating maxillofacial cone beam computed tomography (CBCT) scans and intraoral scans. Study Design Three methods were implemented according to the region of interest (ROI): R0, all teeth included as the registration area (artifacts included); R1, anterior teeth included as the registration area (artifacts in premolars and molars not included); and R2, anterior teeth and second molars included as the registration area (artifacts in premolars and first molars not included). Discrepancies between the 2 images were evaluated by using color-mapping methods. The average surface distance was calculated by measuring the shell/shell deviations for overall discrepancies and 3-dimensional distances between the surface points on the 2 images for registration discrepancies. Results The R1 method showed more discrepancies between the CBCT and intraoral scans compared with the other 2 methods. The R2 method showed smaller overall discrepancy values compared with the R1 method. Most CBCT artifacts were located in the posterior area. Registration discrepancies were greatest in the x-dimension. Conclusions The results suggest that intraoral and CBCT scans might be integrated by using a registration method that involves exclusion of artifacts and inclusion of the second molar on both sides.

Objective Biplanar imaging systems allow for simultaneous acquisition of lateral and frontal cephalograms. The purpose of this study was to compare measurements recorded on three-dimensional (3D) cephalograms constructed from two-dimensional conventional radiographs and biplanar radiographs generated using a new biplanar imaging system with those recorded on cone-beam computed tomography (CBCT)-generated cephalograms in order to evaluate the accuracy of the 3D cephalograms generated using the biplanar imaging system. Methods Three sets of lateral and frontal radiographs of 15 human dry skulls with prominent facial asymmetry were obtained using conventional radiography, the biplanar imaging system, and CBCT. To minimize errors in the construction of 3D cephalograms, fiducial markers were attached to anatomical landmarks prior to the acquisition of radiographs. Using the 3D Ceph™ program, 3D cephalograms were constructed from the images obtained using the biplanar imaging system (3D cephbiplanar), conventional radiography (3D cephconv), and CBCT (3D cephcbct). A total of 34 measurements were obtained compared among the three image sets using paired t-tests and Bland-Altman plotting. Results There were no statistically significant differences between the 3D cephbiplanar and 3D cephcbct measurements. In addition, with the exception of one measurement, there were no significant differences between the 3D cephcbct and 3D cephconv measurements. However, the values obtained from 3D cephconv showed larger deviations than those obtained from 3D cephbiplanar. Conclusions The results of this study suggest that the new biplanar imaging system enables the construction of accurate 3D cephalograms and could be a useful alternative to conventional radiography.

Introduction The purpose of this study was to assess the reproducibility of in-vivo and ex-vivo scans using an intraoral scanner. Methods Twenty adults with no missing teeth except for third molars were included in the study. Alginate impressions were taken, and plaster models were made from the impressions. Each subject underwent full-arch intraoral scanning twice with a TRIOS scanner (3Shape, Copenhagen, Denmark) at an interval of 2 weeks, and, the plaster models were scanned at the same interval with the same scanner. The first images of each scan were superimposed on the second scanned images using surface-based registration. In each case, the differences between the 2 scanned images were evaluated with color mapping. The reproducibility between the in-vivo and ex-vivo scans was compared using independent t tests and Bland-Altman analysis. Results The discrepancies between the first and second images were greater in the posterior than in the anterior regions for both the in-vivo and ex-vivo scans. Average surface differences between the first and second images were greater for the in-vivo scans (0.04 mm) than for the ex-vivo scans (0.02 mm). The Bland-Altman plots showed that the reproducibility of both scans was within the limits of agreement. Conclusions The reproducibility of in-vivo scanning was comparable with ex-vivo scanning, although it showed a slight difference (0.02 mm) compared with ex-vivo scanning.

Introduction The purpose of this study was to examine changes in registration accuracy after including occlusal surface and incisal edge areas in addition to the buccal surface when integrating laser-scanned and maxillofacial cone-beam computed tomography (CBCT) dental images. Methods CBCT scans and maxillary dental casts were obtained from 30 patients. Three methods were used to integrate the images: R1, only the buccal and labial surfaces were used; R2, the incisal edges of the anterior teeth and the buccal and distal marginal ridges of the second molars were used; and R3, labial surfaces, including incisal edges of anterior teeth, and buccal surfaces, including buccal and distal marginal ridges of the second molars, were used. Differences between the 2 images were evaluated by color-mapping methods and average surface distances by measuring the 3-dimensional Euclidean distances between the surface points on the 2 images. Results The R1 method showed more discrepancies between the laser-scanned and CBCT images than did the other methods. The R2 method did not show a significant difference in registration accuracy compared with the R3 method. Conclusions The results of this study indicate that accuracy when integrating laser-scanned dental images into maxillofacial CBCT images can be increased by including occlusal surface and incisal edge areas as registration areas.

Treatment of multiple impacted teeth is challenging. Three-dimensional treatment planning can help in delivering a better outcome. This case report presents a patient with an incomplete dental transposition between the canine and lateral incisor of the maxillary right side associated with the impaction of a dilacerated right central incisor. Using a two-stage surgical exposure and augmented corticotomy, the patient's occlusion and smile esthetics were significantly improved, and Class I occlusal relationships with optimal overjet and overbite were achieved after 50 months of orthodontic treatment. Thirty-month posttreatment records revealed a stable result.

Objective:To compare the condylar displacement following sagittal split ramus osteotomy (SSRO) in asymmetric setback patients between the conventional approach and surgery-first approach and to determine whether the condylar displacement is affected by asymmetric setback in SSRO patients.Materials and Methods:This was a retrospective study. The subjects consisted of patients with facial asymmetry who underwent SSRO and had cone-beam computed tomography taken before and 1 month after surgery. They were allocated into the conventional (n = 18) and surgery-first (SF) groups (n = 20). Descriptive, independent t-tests and Pearson correlation analysis were computed.Results:The amount of condylar displacement in x-, y-, and z-directions and Euclidean distance showed no statistically significant differences between the conventional and SF groups. Comparing the postoperative condylar position with the preoperative position, the condylar displacement occurred in posterior (P < .05) and downward (P < .05) directions in both groups except on the deviated side in the conventional group. The condylar displacement occurred in a posterior (P < .05) direction on the deviated side of the conventional group. However, the condylar displacement in three dimensions showed no statistically significant differences between the two groups. In the correlation analysis, the condylar displacement in both the deviated and contralateral sides showed no significant correlation with asymmetric setback in either group.Conclusion:The condylar displacement in three dimensions and the distance of condylar displacement in SSRO patients with facial asymmetry showed no significant difference between conventional and SF groups. Condylar displacement was not associated with asymmetric setback.

OBJECTIVE To systematically review previous studies and to assess, via a subgroup meta-analysis, the combined odds ratio (OR) of prognostic factors affecting the success of miniscrew implants (MIs) inserted into the buccal posterior region. METHODS Three electronic searches that were limited to articles on clinical human studies using MIs that were published in English prior to March 2015 were conducted. The outcome measure was the success of MIs. Patient factors included age, sex, and jaw of insertion (maxilla vs. mandible), while the MI factors included length and diameter. A meta-analysis was performed on 17 individual studies. The quality of each study was assessed for non-randomized studies and quantified using the Newcastle-Ottawa Scale. The meta-analysis outcome was a combined OR. Subgroup and sensitivity analyses based on the study design, study quality, and sample size of miniscrews implanted were performed. RESULTS Significantly higher success rates were revealed for MIs inserted in the maxilla, for patients ≥ 20 years of age, and for long MIs (≥ 8 mm) and MIs with a large diameter (> 1.4 mm). All subgroups acquired homogeneity, and the combined OR of the prospective studies (OR, 3.67; 95% confidence interval [CI], 2.10-6.44) was significantly higher in the maxilla than that in the retrospective studies (OR, 2.10; 95% CI, 1.60-2.74). CONCLUSIONS When a treatment plan is made, these risk factors, i.e. jaw of insertion, age, MI length, and MI diameter, should be taken into account, while sex is not critical to the success of MIs.

Introduction Our objective was to investigate the dimensional accuracy of digital dental models obtained from the cone-beam computed tomography (CBCT) scans of alginate impressions according to the time elapsed after the impressions were taken. Methods Alginate impressions were obtained of 20 adults using 2 alginate materials: Alginoplast (Heraeus Kulzer, Hanau, Germany) and Cavex (Cavex Holland, Haarlem, The Netherlands). These impressions were stored in wet conditions and scanned by CBCT immediately after impression-taking and after storage times of 12, 24, 36, 48, 60, and 72 hours. After reconstruction of the 3-dimensional digital dental models, the models were measured, and the data were analyzed to determine the dimensional changes according to the time elapsed. The changes within the measurement error were regarded as clinically acceptable in this study. Results The measurement errors ranged from 0.27 to 0.29 mm in the digital dental models obtained from CBCT scans of the alginate impressions. All measurements showed decreasing accuracy with greater elapsed time after the impressions were taken. Changes above the measurement error occurred at 24 and 36 hours for Cavex and Alginoplast, respectively. Conclusions Digital dental models can be obtained from CBCT scans of alginate impressions without sending them to a remote laboratory. However, the impressions need to be scanned within 24 hours; otherwise, dimensional changes lead to errors that exceed the error of measurement.

AIM To explore the involvement of TLR5 in pulp inflammation and to examine the effects of TLR5 activation with its ligand, FlaB protein, on pro-inflammatory gene expression. METHODOLOGY TLR5 expression in dental pulp tissues and human dental pulp cells (hDPCs) were determined by immunohistochemistry, immunocytochemistry, Western blots and RT-PCR analyses. To examine the role of TLR5, hDPCs were treated with recombinant FlaB protein (500 ng mL-1 ) to activate the receptor or with a small interfering RNA against TLR5 (si-TLR5) to downregulate the receptor. After exposure to FlaB, the expression of inflammation-related proteins was screened using a protein array kit. Western blots or qRT-PCR analyses were performed to identify changes in the expression of uPA (urokinase plasminogen activator), TIMPs (tissue inhibitor of metalloproteinases), and IL-6 and to determine their signalling pathways. Statistical analysis was performed using one-way analysis of variance (anova) with Tukey post hoc test; P

The purpose of this study was to evaluate the association between kind of condylar displacement due to orthognathic surgery and the subsequent adaptive condylar head remodeling. The sample in this retrospective cohort study consisted of 30 patients (12 female and 18 male; mean age 22.7 y) with skeletal Class III malocclusion who underwent bilateral sagittal split ramus osteotomy (SSRO). Three-dimensional superimpositions of cone-beam computed tomography (CBCT) scan derived images from immediately after and 6 months after surgery were to reveal the type of remodeling, while images from before and immediately after surgery were to identify the type of condylar displacement. Laterally displaced condyles showed bone resorption on the lateral surfaces and deposition on the medial surfaces, whereas the contrary was found in medially displaced condyles. Anteriorly displaced condyles showed resorption on the anterior surfaces and deposition on the posterior surfaces, whereas the contrary was found in posteriorly displaced condyles. Superior surfaces of the condyles showed bone resorption regardless of displacement direction. The results indicate that condylar remodeling patterns (resorption/deposition) are determined by the direction of condylar displacement during surgery. However, condylar displacement by surgery is not completely compensated by condylar head remodeling, especially in case of downward displacement.

The purpose of this study was to establish the reproducibility of facial soft tissue (ST) thickness measurements by comparing three different measurement methods applied at 32 landmarks on three-dimensional cone-beam computed tomography (CBCT) images. Two observers carried out the measurements of facial ST thickness of 20 adult subjects using CBCT scan data, and inter- and intra-observer reproducibilities were evaluated. The measurement method of "perpendicular to bone" resulted in high inter- and intra-observer reproducibility at all 32 landmarks. In contrast, the "perpendicular to skin" method and "direct" method, which measures a distance between one point on bone and the other point on skin, presented low reproducibility. The results indicate that reproducibility could be increased by identifying the landmarks on hard tissue images, rather than on ST images, and the landmark description used in this study can be used in the establishment of reliable tissue depth data using CBCT images.

Objective: To determine whether the condylar rotation is affected by asymmetric setback in patients undergoing sagittal split ramus osteotomy. Materials and Methods: Thirty patients who underwent bilateral sagittal split ramus osteotomy setback surgery were divided into the two groups, symmetric setback and asymmetric setback, according to the right/left difference of setback amount ( Results: In general, the condylar axis change occurred in a pattern of inward rotation. The condyles in patients undergoing symmetric setback showed 3.4° rotation in average. In case of asymmetric setback, the lesser setback side showed larger value (4.3°) than the greater setback side (2.3°) with a statistical significance. In the correlation analysis, setback amount showed no significant correlation with the condylar axis changes in both groups. However, correlation with right/left setback difference showed a positive correlation in lesser setback side of patients undergoing asymmetric setback. Conclusion: The findings of this study indicate that large amount of setback alone does not contribute to the change in condylar long axis, but asymmetric setback might cause a change in condylar long axis, particularly on the lesser setback side.

Objective: The aim of this study was to assess artifacts induced by metallic restorations in three-dimensional (3D) dental surface models derived by cone-beam computed tomography (CBCT). Methods: Fifteen specimens, each with four extracted human premolars and molars embedded in a plaster block, were scanned by CBCT before and after the cavitated second premolars were restored with dental amalgam. Five consecutive surface models of each specimen were created according to increasing restoration size: no restoration (control) and small occlusal, large occlusal, disto-occlusal, and mesio-occluso-distal restorations. After registering each restored model with the control model, maximum linear discrepancy, area, and intensity of the artifacts were measured and compared. Results: Artifacts developed mostly on the buccal and lingual surfaces. They occurred not only on the second premolar but also on the first premolar and first molar. The parametric values increased significantly with increasing restoration size. Conclusions: Metallic restorations induce considerable artifacts in 3D dental surface models. Artifact reduction should be taken into consideration for a proper diagnosis and treatment planning when using 3D surface model derived by CBCT in dentofacial deformity patients.

OBJECTIVES: To evaluate maxillary and mandibular alveolar and basal bone widths using cone-beam computed tomography (CBCT) and to verify the correlation between CBCT images and posteroanterior (PA) cephalograms. MATERIALS AND METHODS: The CBCT scans and PA cephalograms were obtained from 20 men (age range = 24.0–29.1 years; mean age = 27.2 years; SD = 2.8 years) and 20 women (age range = 20.3–28.1 years; mean age = 26.4 years; SD = 3.2 years) with normal occlusion. On CBCT images, maxillary and mandibular bone widths were measured at three posterior sites and five bone levels. The differences between maxillary and mandibular bone widths were calculated and compared with conventional transverse width of PA cephalograms. RESULTS: Statistically significant differences in maxillary and mandibular bone widths were detected at different levels and sites. Bone widths were significantly increased from the alveolar crest toward the basal bone in the maxillary molar and mandibular second premolar and molar areas. A statistically significant correlation was only found between CBCT images and PA cephalograms for maxillomandibular width at the first molar area. CONCLUSION: The results of this study suggested that three-dimensional assessment of maxillomandibular width is mandatory for the transverse analysis.

One hundred Korean adults (50 men, 50 women) were scanned in the upright position using a cone-beam CT (CBCT) scanner. The soft tissue (ST) thicknesses were measured at 31 landmarks, 10 midline and 21 bilateral landmark sites, and the means and standard deviations were obtained for male and female subjects. While 18 of 31 landmarks showed sex differences, the majority showed higher values for male subjects with the exception of a few landmark sites corresponding to the zygoma area, which showed smaller values in men than in women. The mandibular area showed greater differences between the right and left sides. Overall, the ST thickness measurements obtained in this study can be used as a database for the forensic craniofacial reconstruction of Korean adult faces.

Background The purpose was to investigate the implications of cyclooxygenase-2 (COX-2) and Ki-67 expression on the progression and prognosis of breast cancer. Methods: COX-2 and Ki-67 levels were immunohistochemically determined using tissue microarrays of 1,028 breast tumors treated between November 1999 and August 2005. COX-2 and Ki-67 levels were compared by tumor progression and clinicopathological parameters were investigated in association with both markers status which was divided into 3 subgroups: COX-2(+)/Ki-67(+), COX-2(+)/Ki-67(−), COX-2(−)/Ki-67(any). Results: COX-2 expression was significantly higher in intraductal carcinoma and progressively decreased in small T1 lesions and then in T2-T4 tumors, but Ki-67 was significantly expressed at high levels in T2-T4 lesions than in intraductal or T1 carcinomas. COX-2 expression was positively associated with favorable parameters such as older age at diagnosis, smaller size, well-differentiation, hormone receptor-positivity, and was inversely associated with Ki-67 expression. Among 816 invasive tumors, COX-2 expression alone was not related to outcomes. In combination with Ki-67 expression, however, COX-2(+)/Ki-67(−) tumors were significantly associated with favorable characteristics including HER2−negativity and demonstrated favorable outcomes. COX-2(+)/Ki-67(+) tumors showed unfavorable factors and the worst outcomes. COX-2(−)/Ki-67(any) subgroup presented intermediate prognosis. Statistical significance of COX-2 combined with Ki-67 was maintained in Cox's models adjusting for clinicopathological parameters among not only whole population but also ER-positive subgroup. Conclusions: Our study suggests that COX-2 is expressed in early phase of breast cancer development and is associated with favorable prognostic markers. But co-expression of high Ki-67 proliferative index could indicate an aggressive phenotypic change in COX-2 positive breast cancer. The mechanisms should be further investigated. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-09-35.

The utilization of 3D computerized systems has allowed more effective procedures for forensic facial reconstruction. Three 3D computerized facial reconstructions were produced using skull models from live adult Korean subjects to assess facial morphology prediction accuracy. The 3D skeletal and facial data were recorded from the subjects in an upright position using a cone-beam CT scanner. Shell-to-shell deviation maps were created using 3D surface comparison software, and the deviation errors between the reconstructed and target faces were measured. Results showed that 54%, 65%, and 77% of the three facial reconstruction surfaces had

Objective: To develop a hard coating for stainless surfaces based on silver (Ag)-platinum (Pt) alloys. Materials and Methods: Ag-Pt alloys, which have high degree of biocompatibility, excellent resistance to sterilization conditions, and antibacterial properties to different bacteria, are associated with long-term antibacterial efficiency. Approximately 1.03-µm to 2.34-µm–thick coatings, as determined by scanning electron microscopy, were deposited on stainless surfaces by the simultaneous vaporization of both metals (Ag and Pt) in an inert argon atmosphere. The coating was done by physical vapor deposition. Microorganisms and eukaryotic culture cells were grown on these surfaces. Results: The coatings released sufficient Ag ions when immersed in phosphate-buffered saline and showed significant antimicrobial potency against Streptococcus mutans and Aggregatibacter actinomycetemcomitans strains. At the same time, human gingival fibroblast cells were not adversely affected. Conclusion: Ag-Pt coatings on load-bearing orthodontic bracket surfaces can provide suitable antimicrobial activity during active orthodontic treatment.

Root damage is a significant complication of orthodontic miniscrew implant placement. Although root damage is rare, its proper management should be clearly understood by practitioners. This article reports the iatrogenic root perforation of a mandibular lateral incisor caused by the placement of a miniscrew. Despite a large radiolucent area caused by chronic apical periodontitis, the perforation was successfully repaired by using a recently developed material, mineral trioxide aggregate. The treatment, clinical implications, and clinical guidelines for preventing root damage during miniscrew placement in orthodontic practice are discussed.

The purpose of this retrospective study was to elucidate potential confounding factors affecting initial stability of miniscrews inserted to enhance orthodontic anchorage. Four hundred and seven miniscrews inserted in 168 patients treated by 17 orthodontic residents were analysed in a consecutive chart review. The outcome variable was the stability of the miniscrew, measured as a dichotomous variable, 0 if the miniscrew loosened during a 1 week period after insertion to the time of orthodontic force application and a value of 1 otherwise. Potential confounding variables examined were gender, age, jaw, insertion site, tissue type, length and diameter of the miniscrew, and number of previous insertions. Generalized estimating equations (GEE) methods were used to estimate the influence of each factor on stability for the correlated binary outcomes of each patient. A weighted analysis for the GEE approach was also performed for the convergence calculation of the estimation procedure due to a value of 0 in one of the cells. Crude odds ratio (cOR) and adjusted odds ratio (aOR) and their 95 per cent confidence intervals (CI) were calculated for this purpose. The overall success rate after 1 week was 93.1 per cent (379/407). The screws inserted by more experienced clinicians (more than 20 miniscrews) were found to have approximately a 3.6-fold higher success rate of initial stability compared with those inserted by less experienced clinicians after adjusting for the insertion site (aOR = 3.63, P = 0.015). The results of the present study suggest that the initial stability depends on insertion site and clinician experience.

Introduction: The esthetic impact of the soft-tissue profile might play a major role in deciding on premolar extraction or nonextraction treatment, particularly in borderline patients. The purpose of this study was to compare the esthetic impact of extraction and nonextraction therapy on Korean patients. Methods: Panels of 50 dentists and 50 laypersons evaluated randomly presented pretreatment and posttreatment soft-tissue profiles of 50 extraction and 50 nonextraction patients. As subjects in this study, borderline patients were selected based on their initial diagnostic records. Two panels were asked to compare the pretreatment and posttreatment profile tracings and to quantify their perceptions of the esthetic impact of treatment change using a visual analog scale. Results: Premolar extraction patients showed greater improvement in facial profile compared with nonextraction patients, regardless of the panel. Based on the results of regression analysis to determine the degree of lip protrusion at which the retraction that commonly follows premolar extraction would be needed, the intersection was about 3.0 mm behind the Ricketts’ E-line; this is far behind the Korean norm. Conclusions: The results indicate that premolar extraction is more beneficial than nonextraction treatment in terms of facial profile improvement in Korean borderline patients.

Introduction: In this study, we evaluated errors introduced into the interpretation of facial asymmetry on posteroanterior (PA) cephalograms due to malpositioning of the x-ray emitter focal spot. We tested the hypothesis that horizontal displacements of the emitter from its ideal position would produce systematic displacements of skull landmarks that could be fully accounted for by the rules of projective geometry alone. Methods: A representative dry skull with 22 metal markers was used to generate a series of PA images from different emitter positions by using a fully calibrated stereo cephalometer. Empirical measurements of the resulting cephalograms were compared with mathematical predictions based solely on geometric rules. The empirical measurements matched the mathematical predictions within the limits of measurement error (x= 0.23 mm), thus supporting the hypothesis. Based upon this finding, we generated a completely symmetrical mathematical skull and calculated the expected errors for focal spots of several different magnitudes. Quantitative data were computed for focal spot displacements of different magnitudes. Results and Conclusions: Misalignment of the x-ray emitter focal spot introduces systematic errors into the interpretation of facial asymmetry on PA cephalograms. For misalignments of less than 20 mm, the effect is small in individual cases. However, misalignments as small as 10 mm can introduce spurious statistical findings of significant asymmetry when mean values for large groups of PA images are evaluated.

Background: Facial asymmetry can be evaluated by analyzing some facial lines. The spherical coordinate system is useful to analyze the surgical change to facial lines. This study aims to analyze the amount of asymmetry of facial lines before and after orthognathic surgery using spherical coordinate system from three-dimensional computed tomography (CT). Methods: A retrospective study was carried out on 14 CT scans which were taken from 7 subjects before and after orthognathic surgery (3 males, 4 females, average age of 24 yrs±3 mns). Four bilateral 3D facial lines, ramal height, ramal lateral, ramal posterior and mandibular body lines, were established on each CT scan, and the spherical coordinates (length, midsagittal inclination angle, coronal inclination angle) of each facial line were statistically compared before and after orthognathic surgery. Statistical analysis was done for comparing between before and after surgery in the mental deviation and amount of asymmetry.Results: The menton deviation was statistically significantly reduced by surgery (preoperative 7.67mm±4.46mm, postoperative 2.17 mm±1.58 mm, p

The purpose of this study was to investigate immediate changes in the mandibular dentition after maxillary molar distalization using headgear in non-growing patients. Sixteen patients (mean age, 18.9 ± 2.0 years) with Class II molar relationship and crowding were included in the present study. To correct the molar relationship, headgear was used for maxillary molar distalization. Cone-beam computed tomography-generated half-cephalograms (CG Cephs) and dental casts were used to evaluate dental changes for each subject before and immediately after molar distalization using headgear. The mean duration that subjects wore the headgear was 6.3 months. CG Cephs showed that the first maxillary molars were distalized 4.2 ± 1.6 mm with 9.7° ± 6.1° of distal angulation. The intercanine, interpremolar, and intermolar widths of the mandible increased after maxillary molar distalization. The present study's results suggest that maxillary molar distalization using headgear induces a spontaneous response in the untreated mandibular dentition of non-growing patients.

An anatomical relationship between the hard and soft tissues of the face is mandatory for facial reconstruction. The purpose of this study was to investigate the positions of the eyeball and canthi three-dimensionally from the relationships between the facial hard and soft tissues using cone-beam computed tomography (CBCT). CBCT scan data of 100 living subjects were used to obtain the measurements of facial hard and soft tissues. Stepwise multiple regression analyses were carried out using the hard tissue measurements in the orbit, nasal bone, nasal cavity and maxillary canine to predict the most probable positions of the eyeball and canthi within the orbit. Orbital width, orbital height, and orbital depth were strong predictors of the eyeball and canthi position. Intercanine width was also a predictor of the mediolateral position of the eyeball. Statistically significant regression models for the positions of the eyeball and canthi could be derived from the measurements of orbit and maxillary canine. These results suggest that CBCT data can be useful in predicting the positions of the eyeball and canthi three-dimensionally.

Although posterior tooth intrusion in an adult patient is a difficult procedure, it can be achieved without extruding the adjacent teeth by performing a corticotomy and using magnets. In carrying out this procedure on 2 adult patients whose molars had overerupted due to the early loss of antagonists, tooth movement was rapidly achieved without discomfort or side effects.

Accuracy is the most important factor supporting the reliability of forensic facial reconstruction (FFR) comparing to the corresponding actual face. A number of methods have been employed to evaluate objective accuracy of FFR. Recently, it has been attempted that the degree of resemblance between computer-generated FFR and actual face is measured by geometric surface comparison method. In this study, three FFRs were produced employing live adult Korean subjects and three-dimensional computerized modeling software. The deviations of the facial surfaces between the FFR and the head scan CT of the corresponding subject were analyzed in reverse modeling software. The results were compared with those from a previous study which applied the same methodology as this study except average facial soft tissue depth dataset. Three FFRs of this study that applied updated dataset demonstrated lesser deviation errors between the facial surfaces of the FFR and corresponding subject than those from the previous study. The results proposed that appropriate average tissue depth data are important to increase quantitative accuracy of FFR.

The identification of interrelationship between the hard and soft tissues of the face is mandatory for facial reconstruction. The aim of this study was to investigate the relationship between the hard and soft dimensions of the nose and to predict the position of the nose using cone-beam computed tomography (CBCT) scans obtained from 60 adults. Three-dimensional placements of the nasal soft structures (pronasale, subnasale, ala) from the nasal hard structures (nasal bone, nasal cavity) were measured in order to compute the regression equations to find the most probable position of the pronasale, subnasale, and ala. The positions of the pronasale, subnasale, and ala can be predicted using the regression models. These results suggest that hard and soft tissue relation data from CBCT can be useful for predicting the position of nose.