Precision and reliability of Dolphin 3-dimensional voxel-based superimposition.

INTRODUCTION: Superimposition of 2 cone-beam computed tomography images is possible by using landmarks, surfaces, or density information (voxel-based). Voxel-based superimposition is automated and uses the most image content, providing accurate results. Until recently, this superimposition was extremely laborious, but a user-friendly voxel-based superimposition has recently been introduced. Our aim was to evaluate the precision and reliability of Dolphin 3-dimensional voxel-based superimposition (Dolphin Imaging, Chatsworth, Calif). METHODS: This was a retrospective study using existing scans of 31 surgical orthodontic patients with a mean age of 21 ± 8 years (range, 15-47 years). Each patient had a presurgical and a postsurgical scan taken within 12 months. Surgical patients were used since the reference area for superimposition was not affected by growth or surgical procedures. The volumes were superimposed using voxel-based methods from Dolphin Imaging and a tested method used previously. This method uses 2 open-source programs and takes about 3 hours to complete, whereas the Dolphin method takes under 5 minutes. The postsurgical scan was superimposed on the presurgical scan at the cranial base. Postsurgical registrations for both methods were compared with each other using the absolute closest point color map, with emphasis on 7 regions (nasion, A-point, B-point, bilateral zygomatic arches, and bilateral gonions). RESULTS: Intraclass correlations showed excellent reliability (0.96). The mean differences between the 2 methods were less than 0.21 mm (voxel size, 0.38). The smallst difference was in the left zygomatic area at 0.09 ± 0.07 mm, and the largest was in the right gonial region at 0.21 ± 0.13 mm. CONCLUSIONS: Dolphin 3-dimensional voxel-based superimposition, a fast and user-friendly method, is precise and reliable.

Gingival crevicular fluid bone turnover biomarkers: How postmenopausal women respond to orthodontic activation.

INTRODUCTION: Bone turnover associated with orthodontic tooth movement is evidenced by increased bone turnover markers in gingival crevicular fluid (GCF). Postmenopausal women have an increased concentration of serum bone turnover markers. The filtrate of this serum makes up GCF, but little is known of the bone turnover around teeth in this cohort. The objective of this investigation was to compare the GCF bone turnover markers in premenopausal vs postmenopausal women receiving orthodontic treatment at baseline and at orthodontic activation. METHODS: Twenty-eight women were enrolled in the study and separated into 2 groups: premenopausal (16) and postmenopausal (12). Bone turnover was evaluated by GCF at baseline and 24 hours after orthodontic appliance activation. GCF concentrations of RANKL and OPN were measured using ELISA. Baseline and change in concentrations were compared between groups. RESULTS: Baseline RANKL and OPN were significantly different between the premenopausal and postmenopausal groups (P <0.05). Both markers increased significantly from baseline to 24 hours after orthodontic appliance activation in both groups (P <0.05). However, the response to orthodontic activation was not significantly different between groups. CONCLUSIONS: Although postmenopausal women have a different bone turnover profile at baseline than do their premenopausal counterparts, there is no difference in their response to orthodontic activation. This confers a level of security associated with orthodontic activation. Future studies are warranted to construct biomarker curves throughout orthodontic therapy.

Surface strain distribution of orthodontic miniscrews under load.

INTRODUCTION: Our objective was to investigate surface strain around orthodontic miniscrews under different orthodontic loading conditions in simulated supporting bone. METHODS: Thirty miniscrews with lengths of 6, 8, and 10 mm were embedded into customized composite analog bone models. All miniscrews were inserted into the simulated test bone 6 mm deep and loaded with the same force of 200 cN, creating different tipping moments at the peri-implant bone surface. A digital image correlation technique was used to measure the resulting surface strain around the orthodontic miniscrews. RESULTS: Changing the tipping moments is directly related to the strain generated at the bone surface close to the miniscrews, with greater moments creating greater maximum principal strains. CONCLUSIONS: Within the limitations of this model, it can be stated that greater tipping moments of miniscrews create greater maximum principal strain values, which have the potential to increase bone turnover around the implant. Hence, miniscrews farther from the bone surface should be loaded with less force, whereas miniscrews loaded closer to the bone surface may sustain higher forces.

History of imaging in orthodontics from Broadbent to cone-beam computed tomography.

The history of imaging and orthodontics is a story of technology informing biology. Advances in imaging changed our thinking as our understanding of craniofacial growth and the impact of orthodontic treatment deepened. This article traces the history of imaging in orthodontics from the invention of the cephalometer by B. Holly Broadbent in 1930 to the introduction of low-cost, low-radiation-dose cone-beam computed tomography imaging in 2015.

Cervical vertebral bone mineral density changes in adolescents during orthodontic treatment.

INTRODUCTION: The cervical vertebral maturation (CVM) stages have been used to estimate facial growth status. In this study, we examined whether cone-beam computed tomography images can be used to detect changes of CVM-related parameters and bone mineral density distribution in adolescents during orthodontic treatment. METHODS: Eighty-two cone-beam computed tomography images were obtained from 41 patients before (14.47 ± 1.42 years) and after (16.15 ± 1.38 years) orthodontic treatment. Two cervical vertebral bodies (C2 and C3) were digitally isolated from each image, and their volumes, means, and standard deviations of gray-level histograms were measured. The CVM stages and mandibular lengths were also estimated after converting the cone-beam computed tomography images. RESULTS: Significant changes for the examined variables were detected during the observation period (P ≤0.018) except for C3 vertebral body volume (P = 0.210). The changes of CVM stage had significant positive correlations with those of vertebral body volume (P ≤0.021). The change of the standard deviation of bone mineral density (variability) showed significant correlations with those of vertebral body volume and mandibular length for C2 (P ≤0.029). CONCLUSIONS: The means and variability of the gray levels account for bone mineral density and active remodeling, respectively. Our results indicate that bone mineral density distribution and the volume of the cervical vertebral body changed because of active bone remodeling during maturation.

Effects of orthodontic treatment on human alveolar bone density distribution.

OBJECTIVES: The objective of this study was to examine if non-invasive clinical cone beam computed tomography (CBCT)-based degree of bone mineralization (DBM) measurement can be used to detect the different results from orthodontic treatment between the maxilla and mandible in human patients. MATERIALS AND METHODS: CBCT images were taken before and after orthodontic treatment from 43 patients (19 males and 24 females, 14.36 ± 1.50 years). A histogram of computed tomography (CT) attenuation value, which is equivalent to the DBM, was obtained from the alveolar cortical (AC), trabecular (AT), and enamel (E) regions of each image. Mean, standard deviation (SD), and coefficient of variation (COV) of the CT attenuation values were computed. The regional variations and percentage (%) differences between the E and alveolar regions of the CT attenuation parameters at the maxilla and mandible were analyzed before and after orthodontic treatment. RESULTS: The AC had higher mean and variability (SD and COV) than the AT before and after treatment (p < 0.001). The variability was higher in the mandibular AC than in the maxillar AC (p < 0.01) independent of orthodontic treatment. The percentage (%) difference of variability of CT attenuation values changed for both AT and AC in the maxilla after orthodontic treatment, while that changed for only the AT (p < 0.02), but not for AC, in the mandible (p > 0.16). CONCLUSIONS: The alveolar cortical region of the mandible responded differently to orthodontic treatment compared with other alveolar regions. CLINICAL RELEVANCE: The CBCT-based DBM analysis can be used clinically to assess alveolar bone quality changes induced by orthodontic treatment to improve treatment planning and result evaluation.

Use of cone beam computed tomography to volumetrically assess alveolar cleft defects--preliminary results.

PURPOSE: The purpose of this study was to determine the utility of cone beam computed tomographic (CBCT) imaging in assessing the volume of alveolar cleft defects in patients undergoing secondary cleft repair. MATERIALS AND METHODS: Fourteen patients with unilateral clefts were analyzed in a retrospective study. Preoperative CBCT imaging of patients preparing to undergo secondary repair of alveolar clefts was reviewed. Using anatomic landmarks, 3 measurements were collected from CBCT images for each patient: facial width (FW), facial height (FH), and facial-palatal length (FL). These values were used to calculate the estimated volume (EV) of the cleft and thus the amount of bone graft material that would be needed to fill the defect. RESULTS: The overall mean values of FW, FH, and FL were 9.7 ± 3.1, 14.07 ± 2.7, and 5.6 ± 0.8 mm, respectively. Mean EV was 489.0 ± 151.6 mm(3). The single (0.879) and average (0.956) measurements of the intraclass correlation coefficient for FH were very good to excellent. Similar data were observed for FH (single, 0.827; average, 0.935). For FL, a decreasing trend in the mean and variability over the 3 measurement times was reflected in low single (0.305) and moderate average (0.569) intraclass correlation coefficients. CONCLUSIONS: CBCT imaging can be used to reliably measure FW, FH, and FL and to calculate the EV of the cleft. These data can be used by oral and maxillofacial surgeons to quantitatively assess the volume of an alveolar cleft and aid in preoperative determination of the amount of bone that will be needed to adequately graft the cleft space. This will also aid in appropriate selection of an autogenous graft donor site before surgery.

Comparing a Fully Automated Cephalometric Tracing Method to a Manual Tracing Method for Orthodontic Diagnosis.

Background: This study aims to compare an automated cephalometric analysis based on the latest deep learning method of automatically identifying cephalometric landmarks with a manual tracing method using broadly accepted cephalometric software. Methods: A total of 100 cephalometric X-rays taken using a CS8100SC cephalostat were collected from a private practice. The X-rays were taken in maximum image size (18 × 24 cm lateral image). All cephalometric X-rays were first manually traced using the Dolphin 3D Imaging program version 11.0 and then automatically, using the Artificial Intelligence CS imaging V8 software. The American Board of Orthodontics analysis and the European Board of Orthodontics analysis were used for the cephalometric measurements. This resulted in the identification of 16 cephalometric landmarks, used for 16 angular and 2 linear measurements. Results: All measurements showed great reproducibility with high intra-class reliability (>0.97). The two methods showed great agreement, with an ICC range of 0.70−0.92. Mean values of SNA, SNB, ANB, SN-MP, U1-SN, L1-NB, SNPg, ANPg, SN/ANS-PNS, SN/GoGn, U1/ANS-PNS, L1-APg, U1-NA, and L1-GoGn landmarks had no significant differences between the two methods (p > 0.0027), while the mean values of FMA, L1-MP, ANS-PNS/GoGn, and U1-L1 were statistically significantly different (p < 0.0027). Conclusions: The automatic cephalometric tracing method using CS imaging V8 software is reliable and accurate for all cephalometric measurements.

Correlation of spheno-occipital synchondrosis fusion stages with a hand-wrist skeletal maturity index: A cone beam computed tomography study.

OBJECTIVES: To examine the correlation between spheno-occipital synchondrosis fusion stages and the hand-wrist skeletal maturity index. MATERIALS AND METHODS: Digital records of 164 individuals (77 males, 87 females) aged 10 to 18 years old were examined. Three-dimensional CBCT scans and hand-wrist two-dimensional radiographs were scored for the spheno-occipital synchondrosis fusion stages and hand-wrist skeletal maturity index, respectively. Statistical analyses were performed for associations using R software with a significance threshold of P< .01. RESULTS: A significant positive relationship was demonstrated between spheno-occipital synchondrosis fusion stages and hand-wrist skeletal maturity in both sexes. The Kendall's rank correlation τ between hand-wrist skeletal maturity index and spheno-occipital synchondrosis fusion percentage were high and positive in males and females (r = .74 and r = .71, respectively). CONCLUSIONS: The significant, positive relationship between the hand-wrist skeletal maturity index and spheno-occipital synchondrosis fusion stages support the idea of using spheno-occipital synchondrosis fusion as a biological indicator for craniofacial and mandibular growth spurt prediction.

Reliability and accuracy of cone-beam computed tomography dental measurements.

INTRODUCTION: Dental measurements are an integral part of the orthodontic records necessary for proper diagnosis and treatment planning. In this study, we investigated the reliability and accuracy of dental measurements made on cone-beam computed tomography (CBCT) reconstructions. METHODS: Thirty human skulls were scanned with dental CBCT, and 3-dimensional reconstructions of the dentitions were generated. Ten measurements (overbite, overjet, maxillary and mandibular intermolar and intercanine widths, arch length available, and arch length required) were made directly on the dentitions of the skulls with a high-precision digital caliper and on the digital reconstructions with commercially available software. Reliability and accuracy were assessed by using intraclass correlation and paired Student t tests. A P value of < or = 0.05 was used to assign statistical significance. RESULTS: Both the CBCT and the caliper measurements were highly reliable (r >0.90). The CBCT measurements tended to slightly underestimate the anatomic truth. This was statistically significant only for compounded measurements. CONCLUSIONS: Dental measurements from CBCT volumes can be used for quantitative analysis. With the CBCT images, we found a small systematic error, which became statistically significant only when combining several measurements. An adjustment for this error allows for improved accuracy.

Evaluation of a software program for applying the American Board of Orthodontics objective grading system to digital casts.

INTRODUCTION: The American Board of Orthodontics' objective grading system (ABO OGS) is currently the gold standard for evaluating plaster casts of completed orthodontic cases. METHODS: Thirty-six cases of finished orthodontic casts in plaster and digital form were scored by using 2 methods: an electronic version of the ABO OGS designed to be used with digital casts (OrthoCAD, Cadent, Fairview, NJ) and the ABO gauge designed to be used with plaster casts. The 2 scoring methods were compared using descriptive analysis (range, absolute mean difference, and standard deviation), the Spearman rank correlation coefficient, and the Wilcoxon rank sum test. RESULTS: Intraexaminer reliability was high for both the plaster and the digital casts (r = 0.998). A statistically significant difference (P <.001) was found when comparing the total ABO scores from the plaster and digital casts. The scores from digital casts exceeded the scores from plaster casts by an average of 9.0 +/- 5.4 points. This difference was due to statistically significant differences in 3 ABO OGS components: alignment, occlusal contact, and overjet. CONCLUSIONS: The results indicate that this computer version of the ABO OGS cannot be used as a substitute for manual grading with the ABO ruler.

Image quality produced by different cone-beam computed tomography settings.

INTRODUCTION: The aim of this study was to evaluate image quality at different cone-beam computed tomography settings and 3 fields of view. METHODS: A Hitachi CB MercuRay (Hitachi Medical Systems, Tokyo, Japan) was modified to allow different setting combinations. The variables consisted of 4 milliampere settings (2, 5, 10, and 15 mA), 2 kilovolt (peak) settings (100 and 120 kV[p]), presence or absence of a copper filter, and 3 fields of view (6, 9, and 12 in). Thirty-two scans were taken on a cadaver head and 16 scans on a dry skull. The groups were divided by field of view, and the images were ranked by at least 30 judges. Diagnostic quality was addressed in a questionnaire. Descriptive statistics and rankings were calculated with Excel 2003 (Microsoft, Redmond, Wash) and the Friedman and Wilcoxon signed rank tests with SPSS software (version 14.0.1; SPSS, Chicago, Ill). RESULTS: The presence or absence of a filter showed significant differences (P <.006) in 2 pairs of the 9-in field of view. Variation in kilovolt (peak) settings showed significant differences (P <.006) in the 6-in 5-mA images with a filter. Altering the milliampere settings showed significant differences (P <.008) in the 6- and 12-in groups. The 9-in group showed significant differences between 2 mA and 10 and 15 mA. Overall, the 6-, 9-, and 12-in images had diagnostic quality 56%, 99%, and 99% of the time, respectively. CONCLUSIONS: Presence or absence of a filter and the kilovolt (peak) setting did not affect overall image quality. Images taken at lower milliampere settings showed good diagnostic quality.

Image distortion and spatial resolution of a commercially available cone-beam computed tomography machine.

INTRODUCTION: Our objective was to evaluate images produced by a commercially available cone-beam computed tomography (CBCT) machine (i-CAT model 9140-0035-000C, Imaging Sciences International, Hatfield, Pa) for measurement and spatial resolution (ie, the ability to separate 2 objects in close proximity in the image) for all settings and in all dimensions. METHODS: A custom phantom containing 0.3 mm diameter chromium metal markers approximately 5 mm apart in 3 planes of space was developed for analyzing distortion and measurement accuracy. This phantom was scanned in the CBCT machine by using all 12 commercially available settings. The distance between the markers was measured 3 times on the 3-dimensional images by using a Digital Imaging and Communications in Medicine (DICOM) viewer and was also measured 3 times directly on the phantom with a fine-tipped digital caliper. A line-pair phantom was used to evaluate spatial resolution. Thirty evaluators analyzed images and assigned a resolution from 0.2 to 1.6 mm according to the separation of the line pairs. RESULTS: There were no statistically significant differences among the 3-dimensional images for any setting, in any dimension, or in images divided by thirds in terms of measurement accuracy. Comparison of the CBCT measurements to the direct digital caliper measurements showed a statistically significant difference (P <0.01). However, the absolute difference was <0.1 mm and is probably not clinically significant for most applications. The worst spatial resolution found was 0.86 mm. Spatial resolution was lower at faster scan times and larger voxel sizes. CONCLUSIONS: This CBCT machine has clinically accurate measurements and acceptable resolution.

The Association between the Anatomic Landmarks of the Pulp Chamber Floor and the Prevalence of Middle Mesial Canals in Mandibular First Molars: An In Vivo Analysis.

INTRODUCTION: The present study aimed to determine the incidence and anatomic variation of the middle mesial (MM) canal in mandibular permanent first molars using cone-beam computed tomographic imaging and to evaluate the association between the presence of MM canals and anatomic landmarks of the pulp chamber floor in the mesial root. METHODS: In this in vivo cross-sectional study, 210 CBCT scans of mandibular fist molars from 210 patients were included. CBCT scans were evaluated in 3 sections, and the following data were collected for further analysis: identification of the MM canal, the distance between the mesiobuccal (MB) and mesiolingual (ML) orifices, the presence of any isthmus between the MB and ML orifices, and the MB and ML root canal system (RCS) configurations. Binary logistic regression was performed to assess the effect of pulp floor anatomic characteristics as an independent variable on the outcome variable (the presence of an MM canal). RESULTS: The overall prevalence of the identification of an MM canal regardless of age was 14.7%. Mandibular first molars with an isthmus between the MB and ML RCS configurations were almost 5 times more likely to show an MM canal (P < .05, odds ratio [OR] = 4.9). The MB-ML intraorifice distance was inversely associated with the presence of an MM canal (P < .05, OR = 0.73). Patients less than 42 years old were 4 times more likely to have an MM canal in their CBCT scans compared with patients older than 42 years old (P < .05, OR = 3.9). CONCLUSIONS: The suggested anatomic landmarks of the pulp chamber floor could act as a reliable predictive factor for the presence of an MM canal. This knowledge of anatomic clues may serve to better direct endodontists in locating an MM canal, which could prevent excessive removal of tooth structures.

A comparison of scanned lateral cephalograms with corresponding original radiographs.

INTRODUCTION: Digital cephalometric radiography is gaining popularity in orthodontic practices. However, few studies have compared measurements and superimpositions on analog radiographs with those made on scanned digital images. The objectives of this study were to evaluate distortion associated with scanning lateral cephalograms and printing to hard copy, and to assess the accuracy of digital images for regular cephalometric tasks. METHODS: Pretreatment and posttreatment cephalograms from 30 subjects were selected and 3 groups were created: original, digital, and hard copy. All films had 8 fiducial marks punched and were scanned at 150 dots per inch. The hard copies were created with a laser printer. Twenty-three cephalometric measures and 3 superimpositions were evaluated for distortion, measurement accuracy, and superimposition results. Paired t tests were used to assess statistical significance. RESULTS: Distortion between the original and the scanned image showed 0.8 mm vertical enlargement and 0.4 mm horizontal reduction. Printed radiographs had 1.1 mm vertical and 0.4 mm horizontal enlargement. All differences were statistically significant. Cephalometric comparisons between original and digital images showed statistical differences in Frankfort horizontal (FH)-occlusal plane, maxillary central incisor-FH, facial plane, y-axis, Frankfort plane to mandibular plane angle (FMA), and FH-Naison to point A (NA). Significant differences also were found in facial plane, y-axis, FMA, and FH-NA when comparing the digital and the hard-copy images. All measurements with differences contained the landmarks porion and orbitale. No differences were found between the original and the hard-copy images. Likewise, no significant differences were found between the original and the digital superimpositions. CONCLUSIONS: Although some distortion was found, the relatively small horizontal and vertical discrepancies were deemed clinically insignificant. Landmark identification errors on scanned images contributed to the discrepancies in cephalometric analysis. Therefore, for clinical orthodontic applications, scanned cephalograms can be used. However, caution must be exercised when determining porion and orbitale.

Cephalometric changes in overbite and vertical facial height after removal of 4 first molars or first premolars.

INTRODUCTION: The objective of this study was to evaluate the outcome of standard edgewise orthodontic treatment with extraction of 4 first molars (6xT group) or Tweed edgewise treatment with extraction of 4 first premolars (4xT group). MATERIALS AND METHODS: A cephalometric analysis that isolated tipping and bodily tooth movements of the maxillary and mandibular incisors and measured vertical skeletal changes in the anterior region of the maxilla and mandible was used. Thirty subjects treated by 10 practitioners comprised the 6xT group, whereas 31 subjects treated in the Case Western Reserve University orthodontic clinic were used in the 4xT group. Control groups (6xC and 4xC) were selected from untreated subjects enrolled in the Bolton-Brush Growth Study and were matched on age and gender. Data were collected before (T1) and after (T2) treatment. RESULTS: Analysis of the data showed no statistically significant changes between 6xT and 6xC for any of the variables studied. An increase in overbite of 2.1 mm in the 6xT group was the result of small but clinically significant changes in both tipping and extrusion of maxillary and mandibular incisors. In the 4xT group, statistically and clinically significant changes were observed for intrusion of the maxillary and mandibular incisors, resulting in a 4.1-mm decrease in overbite. Importantly, both the 6xT and the 4xT groups showed no increase in mandibular vertical height during treatment. CONCLUSION: Both treatment strategies showed good control of vertical mandibular growth. Bodily intrusion of anterior teeth was the main contributor to correction of deep overbite in the Tweed edgewise sample.

Nonsurgical treatment of a patient with a Class III malocclusion.

A patient with a bilateral Class III molar relationship came to the Department of Orthodontics clinic at Case Western Reserve University. Our first choice for treatment was a combination of orthodontic therapy and orthognathic surgery. The patient, however, opted for a nonsurgical approach that took 34 months and involved the extraction of 4 first premolars and a remaining deciduous tooth, and Class III vertical elastics. Although orthodontic treatment was considered to be a second-line alternative, the results suggest that, for some surgical patients, orthodontic treatment alone might be a better choice because of the favorable cost/benefit ratio.

Gingival enlargement and resolution during and after orthodontic treatment.

Gingival enlargement (GE) is a condition that commonly develops during orthodontic treatment. Thirty adolescent subjects with clinically significant GE were analyzed at pre-orthodontic treatment (T1), when the appliances were removed (T2), and 3 to 12 months after (T3). The mean GE decreased from T2 to T3, but was significantly higher on T3 than T1 (p<.05). It may be concluded that complete resolution of GE developed during orthodontic treatment is not always attained after removal of the fixed appliances.