Cone beam computed tomography use in orthodontics

Cone beam computed tomography (CBCT) is widely used by orthodontists to obtain three‐dimensional (3‐D) images of their patients. This is of value as malocclusion results from discrepancies in three planes of space. This review tracks the use of CBCT in orthodontics, from its validation as an accurate and reliable tool, to its use in diagnosing and treatment planning, and in assessing treatment outcomes in orthodontics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90211/1/j.1834-7819.2011.01662.x.pd

Dimensional Changes of Upper Airway after Rapid Maxillary Expansion: A Prospective Cone-beam Computed Tomography Study

Introduction: The aim of this prospective study was to use cone-beam computed tomography to assess the dimensional changes of the upper airway in orthodontic patients with maxillary constriction treated by rapid maxillary expansion. Methods: Fourteen orthodontic patients (mean age, 12.9 years; range, 9.7-16 years) were recruited. The patients with posterior crossbite and constricted maxilla were treated with rapid maxillary expansion as the initial part of their comprehensive orthodontic treatments. Before and after rapid maxillary expansion conebeam computed tomography scans were taken to measure the retropalatal and retroglossal airway changes in terms of volume, and sagittal and cross-sectional areas. The transverse expansions by rapid maxillary expansion were assessed between the midlingual alveolar bone plates at the maxillary first molar and first premolar levels. The measurements of the before and after rapid maxillary expansion scans were compared by using paired t tests with the Bonferroni adjustment for multiple comparisons. Results: After rapid maxillary expansion, significant and equal amounts of 4.8 mm of expansion were observed at the first molar (P 5 0.0000) and the first premolar (P 5 0.0000) levels. The width increase at the first premolar level (20.0%) was significantly greater than that at the first molar level (15.0%) (P 5 0.035). As the primary outcome variable, the cross-sectional airway measured from the posterior nasal spine to basion level was the only parameter showing a significant increase of 99.4 mm2 (59.6%) after rapid maxillary expansion (P 5 0.0004). Conclusions: These results confirm the findings of previous studies of the effect of rapid maxillary expansion on the maxilla. Additionally, we found that only the cross-sectional area of the upper airway at the posterior nasal spine to basion level significantly gains a moderate increase after rapid maxillary expansion

Detection of bone defects using CBCT exam in an Italian population

Background. The aim of this study was to evaluate the in vivo incidence and the location of fenestrations in a young Italian population by using CBCT. Materials and Methods. Fifty patients who had previously performed CBCT for planning third molar extraction or orthodontic therapy were selected for the study. No previous dental treatment had been performed on these patients. Overall, 1,395 teeth were evaluated. Root fenestrations were identified according to the definition of Davies and the American Association of Endodontists. Data was collected and statistically analyzed. Results. Fenestrations were observed in 159 teeth out of 1,395 (11% of teeth). In the lower jaw, we found 68 fenestrations (5%) and 91 in the maxilla (6,5%). Incisors were the teeth with the highest incidence of fenestrations. Conclusion.The relative common finding (11%)of fenestration supports the need for CBCT exams before any surgical/implant treatment to avoid complications related to the initial presence of fenestrations. CBCT was found to be an effective and convenient tool for diagnosing fenestration

Diagnostic accuracy of cone-beam computed tomography in detecting secondary caries under composite fillings: An in vitro study

Purpose: The aim of this in vitro study was to assess the diagnostic performance of cone-beam computed tomography (CBCT) in the detection of secondary carious lesions under composite resin fillings applied to different types of cavities. Materials and Methods: Occlusal cavities (O) (n=18), occlusal cavities with mesial or distal component (MO/DO) (n=30), and mesial–occlusal–distal cavities (MOD) (n=30) were prepared in seventy eight extracted human posterior teeth. In half of the cavities in each group, artificial secondary caries lesions were simulated. All cavities were restored by using composite resin. All specimens were embedded in silicone and they were positioned to have approximal contacts. CBCT imaging was done and data were evaluated two times with two week interval by two observers, using a five-point confidence scale. Intra- and inter-observer agreements were calculated with Kappa statistics (κ). The area under (Az) the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy. Results: Intra- (κ =0.89) and inter-observer (κ = 0.79) agreements were found to be excellent. Az values were highest for the O restorations which is followed by the MOD and DO/MO restorations. Az values for MOD and DO/MO restorations were very low and no statistically significant difference was found. Sensitivity for DO/MO restorations and specificity for MOD restorations were found to be the lowest values. Conclusion: Diagnostic performance of CBCT was higher in O composite restorations than MOD and DO/MO restorations for secondary caries detection. The use of alternative imaging methods rather than CBCT may be useful for evaluating secondary caries under composite MOD and DO/MO restorations

Rapid maxillary expansion and upper airway morphology: a systematic review on the role of cone beam computed tomography

OBJECTIVE: This study aimed to investigate the quality of cone beam computed tomography (CBCT) studies evaluating the effects of rapid maxillary expansion on upper airway morphology. MATERIALS AND METHODS: A database search was conducted using PubMed, Ovid, and Cochrane Library up to December 2016. Studies in which CBCT was adopted to visualize the upper airway before and after rapid maxillary expansion were included. The population target was growing patients. Methodological quality assessment was performed. RESULTS: The screening process resulted in the exclusion of 1079 references, resulting in only 9 remaining papers that fulfilled the inclusion criteria. No randomized clinical trials were found. The quality scores ranged from 36% to 68% of the maximum achievable, and the mean quality score of the studies was 50%. No good quality studies were detected in our sample. CONCLUSIONS: Inconsistencies in the CBCT protocols utilized were detected between studies. Head posture, tongue position, and segmentation protocols were not consistent. These discrepancies were reflected in the different results obtained in the studies. A valid and consistent protocol with regard to head and tongue positioning, as well as nasal cavity volume segmentation, is required

Three-dimensional analysis of mandibular landmarks, planes and shape, and the symphyseal changes associated with growth and orthodontic treatment

OBJECTIVE: To test reliability of 3D mandibular landmarks, planes of reference and surfaces and assess their correlation to conventional 2D cephalometric measurements. To analyze changes in three-dimensional shape of the symphysis due to growth and orthodontic treatment. METHODS: This was a retrospective analysis of CBCTs of healthy orthodontic patients. 32 subjects were included, 16 males and 16 females. Mean ages of 10.6 ± 1.5 years and 15.0 ± 0.9 years before and after treatment, respectively. The mean follow up time was 4.3 years. Subjects free of any craniofacial anomalies, and no observable pathology on panoramic radiograph were. 15 subjects had CVM 1 and 17 subjects had CVM 2 before orthodontic treatment. All subjects had CVM 5 after orthodontic treatment. For the first phase, 3D mandibular landmark identifications were digitized. Planes and landmarks were constructed and compared with conventional 2D mandibular measurements. For the second phase, mandibles were isolated by removing surrounding structures. Pearson correlation and paired t-test were performed to test for correlation and differences between 2D and 3D measurements, respectively. Statistical analysis was performed using SAS 9.4. Software. MorphoJ software (Version 2.0, www.flywings.org.uk) was used for symphysis shape analysis; and Discriminant Function Analysis (DFA) between pre-treatment and post-treatment was used for statistical analysis of the symphysis. RESULTS: We found statistical significant positive correlation between 2D and 3D pre-treatment ramus height (P-value =0.01), post-treatment ramus height (P-value < 0.0001), pre-treatment corpus length (P-value 0.0003), post-treatment corpus length (P-value 0.04), pre-treatment gonial angle (P-value <0.0001), and post-treatment gonial angle (P-value=0.05). Also, statistically significant differences in 2D ramus height (P=0.001), 3D ramus height (P-value=0.002), 2D corpus length (P-value <0.01), and 3D corpus length (P-value <0.01). For symphysis shape comparing between pre-treatment and post-treatment, we found that there is no statistically significant difference between them (P-value= 0.99). CONCLUSION: These results demonstrated statistically significant positive correlation between certain 2D and 3D measurements, pre-treatment and post-treatment differences in 2D and 3D measurements showed consistent results. Symphysis shapes do break out as distinctly separate groups, but the differences between the means is small

Accuracy of linear measurement using cone-beam computed tomography at different reconstruction angles

Purpose: This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Materials and Methods: Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., 0°), +10°, +12°, -12°, and -10° with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. Results: The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of -12°, -0.66 to -0.11 at -10°, -0.51 to +0.19 at 0°, -0.64 to +0.08 at +10°, and -0.64 to +0.1 at +12°. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Conclusion: Changing the slice orientation in the range of -12°to +12°reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable. © 2014 by Korean Academy of Oral and Maxillofacial Radiology

Morphologic characteristics, location, and associated complications of maxillary and mandibular supernumerary teeth as evaluated using cone beam computed tomography

SUMMARYOBJECTIVES: To evaluate the location and morphologic characteristics of supernumerary teeth and to assess the frequency and extent of root resorption of adjacent teeth using cone beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT scans of 82 patients with supernumerary teeth in the maxilla and mandible were evaluated by two orthodontists independently. Data regarding the type, shape, and three-dimensional (3D) location of the supernumeraries including the frequency and extent of root resorption of adjacent teeth were recorded and evaluated for possible associations. RESULTS: The study comprised a total of 101 supernumerary teeth. Most of the patients (80.5 per cent) exhibited one single supernumerary tooth, while 15.8 per cent had two and 3.7 per cent had three supernumeraries. Males were affected more than females with a ratio of 1.65:1. Mesiodentes were the most frequently diagnosed type of supernumerary teeth (48.52 per cent), followed by supernumerary premolars (23.76 per cent) and lateral incisors (18.81 per cent). Supernumeraries were most commonly conical in shape (42.6 per cent) with a normal or inclined vertical position (61.4 per cent). Root resorption of adjacent teeth was detected for 22.8 per cent of the supernumerary teeth, most frequently for supernumerary premolars. There was a significant association between root resorption of adjacent teeth and type and shape of tooth. Interrater agreement for the measurements performed showed kappa values ranging from 0.55 to 1 with a kappa value of 1 for type and shape of the supernumerary teeth. CONCLUSIONS: CBCT provides 3D information about location and shape of supernumerary teeth as well as prevalence and degree of root resorption of neighbouring teeth with moderate to high interrater correlatio

eine in vitro-Untersuchung

Zielsetzung: Kiefermodelle können mit Modellscannern, intraoralen Scannern und mittlerweile auch digitalen Volumentomographie (DVT)-Geräten digitalisiert werden. Das Ziel dieser Studie war es, die Genauigkeit der verschiedenen direkten und indirekten Digitalisierungsverfahren anhand von drei klinisch relevanten Strecken zu vergleichen. Methode: Ein als Patient dienendes Studienmodell wurde dreidimensional gedruckt und mittels Doppelmischtechnik abgeformt. Die Abformung wurde mit Gips ausgegossen. An beiden Modellen wurden die Masterwerte für die Zahnbogenlänge, die Intermolarenweite und die Intercaninenweite, mit einem Koordinatenmessgerät (Zeiss O-Inspect 422) gemessen. Anschließend wurde das gedruckte Modell mit sechs Intraoralscannern gescannt. Das Gipsmodell wurde mit elf Modellscannern und fünf DVT-Geräten gescannt. Pro Gerät wurden 37 Scans angefertigt. Die resultierenden Stereolithografie-Daten wurden exportiert und mit einer speziellen Messsoftware (ConvinceTM Premium 2012 (3Shape)) linear vermessen. Alle Messungen wurden mit den Masterwerten des entsprechenden Modelles verglichen. Ergebnisse: Die Genauigkeitsmessungen ergaben signifikante Unterschiede zwischen den Digitalisierungsverfahren sowie den Gerätegruppen. Die höchsten Genauigkeiten erzielten die Modellscanner und einzelne DVT-Geräte. Weitere DVT-Geräte zeigten eine etwa vierfach höhere mittlere Abweichung. Die Intraoralscanner wiesen sowohl bei der mittleren Abweichung als auch der Standardabweichung etwa vierfach höhere Werte auf als die Modellscanner. Schlussfolgerung: Einige DVT-Geräte eignen sich zur Digitalisierung von Gipsmodellen und weisen klinisch eine sehr gute Genauigkeit auf, sodass Praxen die mit DVT-Geräten ausgestattet sind Gipsmodelle digitalisieren könnten ohne zusätzliche Geräte zu benötigen.Objective: Dental models can be digitized with model scanners, intraoral scanners and recently also by cone-beam computed tomography. The aim of this study is to investigate the accuracy of various direct and indirect digitization procedures using three clinically relevant distances. Method: A study model serving as a patient was printed three-dimensionally and molded using a double mix technique. The impression was casted with plaster. The master values for the length of the archlength, the intermolar width and the intercanine width were measured on both models using a coordinate measuring device (Zeiss OInspect 422). The printed model was then scanned with six intraoral scanners. The plaster model was scanned with eleven model scanners and five CBCT devices. 37 scans were taken per device. The resulting stereolithography data were exported and measured linearly using special measuring software (Convince ™ Premium 2012 (3Shape)). All measurements were compared with the master values of the respective model. Results: The accuracy measurements showed significant differences between the digitization methods and the device groups. The highest accuracy was achieved using model scanners and some CBCT devices. Other CBCT devices showed a four times higher mean deviation. The intraoral scanners showed about four times higher values for both the mean deviation and the standard deviation than the model scanners. Conclusion: Some CBCT devices are suitable for the digitization of plaster models and show very good clinical accuracy. Dental offices equipped with CBCT devices could digitize plaster casts without the need for additional devices

Changes in the midpalatal and pterygopalatine sutures induced by micro-implant-supported skeletal expander, analyzed with a novel 3D method based on CBCT imaging.

BackgroundMini-implant-assisted rapid palatal expansion (MARPE) appliances have been developed with the aim to enhance the orthopedic effect induced by rapid maxillary expansion (RME). Maxillary Skeletal Expander (MSE) is a particular type of MARPE appliance characterized by the presence of four mini-implants positioned in the posterior part of the palate with bi-cortical engagement. The aim of the present study is to evaluate the MSE effects on the midpalatal and pterygopalatine sutures in late adolescents, using high-resolution CBCT. Specific aims are to define the magnitude and sagittal parallelism of midpalatal suture opening, to measure the extent of transverse asymmetry of split, and to illustrate the possibility of splitting the pterygopalatine suture.MethodsFifteen subjects (mean age of 17.2&nbsp;years; range, 13.9-26.2&nbsp;years) were treated with MSE. Pre- and post-treatment CBCT exams were taken and superimposed. A novel methodology based on three new reference planes was utilized to analyze the sutural changes. Parameters were compared from pre- to post-treatment and between genders non-parametrically using the Wilcoxon sign rank test. For the frequency of openings in the lower part of the pterygopalatine suture, the Fisher's exact test was used.ResultsRegarding the magnitude of midpalatal suture opening, the split at anterior nasal spine (ANS) and at posterior nasal spine (PNS) was 4.8 and 4.3&nbsp;mm, respectively. The amount of split at PNS was 90% of that at ANS, showing that the opening of the midpalatal suture was almost perfectly parallel antero-posteriorly. On average, one half of the anterior nasal spine (ANS) moved more than the contralateral one by 1.1&nbsp;mm. Openings between the lateral and medial plates of the pterygoid process were detectable in 53% of the sutures (P&nbsp;&lt;&nbsp;0.05). No significant differences were found in the magnitude and frequency of suture opening between males and females. Correlation between age and suture opening was negligible (R 2 range, 0.3-4.2%).ConclusionsMidpalatal suture was successfully split by MSE in late adolescents, and the opening was almost perfectly parallel in a sagittal direction. Regarding the extent of transverse asymmetry of the split, on average one half of ANS moved more than the contralateral one by 1.1&nbsp;mm. Pterygopalatine suture was split in its lower region by MSE, as the pyramidal process was pulled out from the pterygoid process. Patient gender and age had a negligible influence on suture opening for the age group considered in the study