Evaluation of CBCT digital models and traditional models using the Little's Index

Comparison of the efficiency of initial dental alignment with Invisalign® aligners changed every 7 or 14 days in mature adults: Randomized clinical trial

OBJECTIVE

To compare the anterior crowding correction after sequential use of the first 5 aligners between two aligner exchange protocols (7 and 14 days) in mature adult patients.

MATERIALS AND METHODS

Thirty-six patients over 35 years who received orthodontic treatment with Invisalign® were randomly allocated to two different aligner replacement sequence protocols: Group 1: exchange every 7 days (n = 18); and Group 2: exchange every 14 days (n = 18). All patients were scanned with iTero Element 5D® (Align Technology) in two treatment times: at pre-treatment (T1) and after using the first five aligners (T2). Little's Irregularity Index (LII) and arch widths were evaluated with OrthoCAD software. Intra and intergroup comparisons were performed with the dependent and independent t-tests. The results were considered significant for P < .05.

RESULTS

Thirty-five patients completed the study. Both groups' maxillary and mandibular Irregularity Indexesi were significantly lower at T2. There was no significant difference in inter-canine, inter-premolar, and intermolar distances. G2 (14 days) presented a greater decrease in mandibular irregularity than G1 (7 days).

CONCLUSION

Both exchange protocols (7 and 14 days) effectively correct anterior crowding in the initial phase of orthodontic treatment with aligners in mature adult patients. However, the 14-day exchange protocol provided a greater correction in mandibular anterior crowding in the evaluated period than the 7-day exchange protocol.

Comparison of the accuracy of three interproximal reduction methods used in clear aligner treatment

OBJECTIVES

To comparatively assess 3 interproximal reduction (IPR) methods used in clear aligner treatment with regard to accuracy, and patient perception of discomfort and anxiety.

MATERIALS AND METHODS

A total of 42 patients, treated with the Invisalign® system, were included in this prospective trial and received one of the following IPR methods: hand-operated abrasive strips (group 1; 14 patients, 150 teeth), motor-driven 3/4 oscillating segmental discs (group 2; 14 patients, 134 teeth), or motor-driven abrasive strips (group 3; 14 patients, 133 teeth). Accuracy was evaluated using the difference between planned and executed IPR. Anxiety and discomfort levels experienced by the patients were evaluated using a questionnaire of 17 questions.

RESULTS

The accuracy of IPR was high in groups 2 and 3; however, it was low in group 1 with the executed IPR significantly less than the planned amount. On quadrant-level, executed IPR was significantly less in the upper left quadrant in group 1, and significantly more in the upper right quadrant in group 2. The difference between planned IPR and executed IPR was significant for teeth 11, 21, 32, 33, and 43 in group 1, indicating deficiency. The average difference between planned IPR and executed IPR was 0.08 mm for group 1, 0.09 mm for group 2, and 0.1 mm for group 3. Anxiety and discomfort levels did not differ between the methods, but a negative correlation was observed between age and discomfort and anxiety levels.

CONCLUSIONS

The overall accuracy of the 2 motor-driven IPR methods was found to be better than the hand-operated system. Maxillary central incisors and mandibular canines were more prone to IPR deficiency when hand-operated abrasive strips were utilized. Patients were similarly comfortable with all 3 methods, and discomfort and anxiety levels decreased with age.

CLINICAL RELEVANCE

Motor-driven methods have proven to be more effective when compared to the hand-operated ones by means of precision, speed, and patient comfort. If the clinician favors a hand-operated method, it may be advised to perform slightly more IPR especially on mandibular canines and maxillary central incisors.

The Validity and Reliability of Automatic Tooth Segmentation Generated Using Artificial Intelligence

This study aimed at evaluating the precision of the segmented tooth model (STM) that was produced by the artificial intelligence (AI) program (CephX®) with an intraoral scan (IOS) and insignia outcomes. Methods. 10 patients with Cl I malocclusion (mild-to-moderate crowding) who underwent nonextraction orthodontic therapy with the Insignia™ system had IOS and CBCT scans taken before treatment. AI was used to produce a total of 280 STMs; each tooth will be measured from three aspects (apexo-occlusal, mesiodistal, and labiolingual) for DICOM and STL formats. Also, root volume measurements for each tooth generated by using the CephX® software and Insignia™ system were compared. The software used for these measurements was the OnDemand3D program used for the multiplanar reconstruction for DICOM format and Geomagic® Control X™ used for STL format. Statistics. An intraclass correlation (ICC) analysis was used to check the agreement between the volume measurement of the segmented teeth generated by using the CephX® and Insignia™ system. Also, it was used to check the agreement between the STL (IOS), STL (CephX®), and DICOM tooth models. In addition, it was used to determine the intraexaminer repeatability by remeasuring five randomly selected individuals two weeks after the initial measurement. After confirmation of the data normality using the Shapiro-Wilk test, the right and left tooth models and the differences between the DICOM, CephX® (STL), and IOS (STL) tooth models were compared using a paired t-test. The STL (IOS), STL (CephX®), and DICOM tooth models were compared utilizing the ANOVA test. p < 0.05 was set as the statistical significance level. Result. Overall data showed good agreement with ICC. The measurements of the various tooth types on the right and left sides did not differ significantly. Also, there was no significant difference between the three groups. Conclusions. The automatic AI approach (CephX®) may be advised in the clinical practice for patients with mild crowding and no teeth restorations due to its speed and effectiveness.

Accuracy of three-dimensional printed models derived from cone-beam computed tomography

OBJECTIVES

To determine the accuracy of three-dimensional (3D) printed models fabricated from cone-beam computed tomography (CBCT) scans of human mandibular dry skulls in comparison with models derived from intraoral scanner (IOS) data.

MATERIALS AND METHODS

Six human mandibular dry skulls were scanned by IOS and CBCT. Digital models (DMs) constructed from the IOS and CBCT data were fabricated physically using a 3D printer. The width and thickness of individual teeth and intercanine and molar widths were measured using a digital caliper. The accuracy of the DMs was compared between IOS and CBCT. Paired t-tests were used for intergroup comparisons.

RESULTS

All intraclass correlation coefficient values for the three measurements (mesial-distal, buccal-lingual, width) exceeded 0.9. For the mandibular teeth, there were significant discrepancies in model accuracy between the IOS (average discrepancies of 0.18 ± 0.08 mm and 0.16 ± 0.12 mm for width and thickness, respectively) and CBCT (0.28 ± 0.07 mm for width, 0.37 ± 0.2 mm for thickness; P &lt; .01). Intercanine (P = .38) and molar widths (P = .41) showed no significant difference between groups.

CONCLUSIONS

There was a statistically significant difference in the accuracy of DMs obtained from CBCT and IOS; however, this did not seem to result in any important clinical difference. CBCT could be routinely used as an orthodontic diagnostic tool and for appliance construction.

Assessment of the accuracy of laser-scanned models and 3-dimensional rendered cone-beam computed tomographic images compared to digital caliper measurements on plaster casts

Purpose

This study investigated the accuracy of laser-scanned models and 3-dimensional (3D) rendered cone-beam computed tomography (CBCT) compared to the gold standard (plaster casts) for linear measurements on dental arches.

Materials and Methods

CBCT scans and plaster models from 30 patients were retrieved. Plaster models were scanned by an Emerald laser scanner (Planmeca, Helsinki, Finland). Sixteen different measurements, encompassing the mesiodistal width of teeth and both arches' length and width, were calculated using various landmarks. Linear measurements were made on laser-scanned models using Autodesk Meshmixer software v. 3.0 (Autodesk, Mill Valley, CA, USA), on 3D-rendered CBCT models using OnDemand 3D v. 1.0 (Cybermed, Seoul, Korea) and on plaster casts by a digital caliper. Descriptive statistics, the paired t-test, and intra- and inter-class correlation coefficients were used to analyze the data.

Results

There were statistically significant differences between some measurements on plaster casts and laser-scanned or 3D-rendered CBCT models (P<0.05). Molar mesiodistal width and mandibular anterior arch width deviated significantly different from the gold standard in both methods. The largest mean differences of laser-scanned and 3D-rendered CBCT models compared to the gold standard were 0.12±0.23 mm and 0.42±0.53 mm, respectively. Most of the mean differences were not clinically significant. The intra- and inter-class correlation results were acceptable for all measurements (>0.830) and between observers (>0.801).

Conclusion

The 3D-rendered CBCT images and laser-scanned models were useful and accurate alternatives to conventional plaster models. They could be used for clinical purposes in orthodontics and prostheses.

The Effect of Immediate Versus Delayed Addition of the Nasal Stent to the Nasoalveolar Molding Plate on Nostrils Shape and Cleft Width in Infants With Unilateral Cleft Lip and Palate

OBJECTIVE

The main aim of this study was to evaluate the effect of immediate versus delayed addition of the nasal stent to the nasoalveolar molding plate on the nose shape and alveolar cleft area in unilateral cleft lip and palate infants.

METHOD

Twenty nonsyndromic newborn infants with unilateral cleft lip and palate were scanned 3 dimensionally using Proface software. In the experimental group, the nasal stent was added on the day the molding plate arrived, and in the control group when the alveolar gap reached 5 mm. Two months after adding nasal stents in each group patients' faces were scanned again and some parameters were measured. In addition, immediately after treatment, 1 month later and at the end of investigation, impressions were taken, and stone casts were scanned by cone-beam computed tomography and the alveolar gap was measured. Fisher exact test, paired t test, and ANOVA were used for data analyses. P < 0.05 was considered as significant.

RESULTS

In this study, changes in the parameters showed significant differences between the case and controls for the columellar angle, nostril width on the cleft side, nostril height on the cleft side, soft tissue cleft width, and nasal surface area. However, the nostril's width and height in the noncleft side, intercommissural distance, nasal surface area on the noncleft side, nostril area between the cleft and noncleft side after treatment, and the alveolar gap did not show significant differences between the groups (P > 0.05).

CONCLUSION

Early use of nasal stents showed more desirable results in decreasing the width of the nostrils and increasing its height and correcting the angle of the columella without any adverse effects on the nostrils after treatment.

Quantitative evaluation of implemented interproximal enamel reduction during aligner therapy

OBJECTIVES

To investigate the correspondence between programmed interproximal reduction (p-IPR) and implemented interproximal reduction (i-IPR) in an everyday-practice scenario. The secondary objective was to estimate factors that might influence i-IPR to make the process more efficient.

MATERIALS AND METHODS

Fifty patients treated with aligner therapy by six orthodontists were included in this prospective observational study. Impressions were taken at the beginning of treatment and after the first set of aligners. Data on p-IPR, i-IPR and technical aspects of IPR were gathered for 464 teeth. Statistical analyses included the Wilcoxon signed-rank test, Kruskal-Wallis, and multilevel mixed regression.

RESULTS

Mean difference between p-IPR and i-IPR was 0.15 mm (SD: 0.14 mm; P = .0001), with lower canines showing the highest discrepancy. Use of burs and measuring gauges resulted in a smaller difference (respectively: coeff.: 0.09, P = .029; coeff.: -0.06, P = .013). IPR was performed more accurately on the mesial surface of teeth than on the distal surface. Round tripping before IPR resulted in a slightly more precise i-IPR compared to the previous alignment (coeff.: -0.021, P = .041).

CONCLUSIONS

Implemented IPR tends to be less than p-IPR, especially for lower canines and distal surfaces of teeth. Burs tend to provide more precise i-IPR, especially compared to manual strips; however, there is variation between the techniques. Using a measuring gauge tends to increase the precision of i-iPR. As several factors influence the implementation of IPR, particular attention must be paid during the procedure to maximize its precision.

Effectiveness of vibrational forces on orthodontic treatment : A randomized, controlled clinical trial

AIM

AcceleDent® Aura (OrthoAccel® Technologies, Bellaire, TX, USA) is a class II medical device with U.S. Food and Drug Administration approval that uses SoftPulse Technology™ to increase the speed of tooth movement. The aim of this study was to evaluate the application of vibrational forces on the rate of canine distalization.

METHODS

A total of 20 patients (10 boys and 10 girls) who had class II division 1 malocclusion or severe crowding and indicated first premolar extractions for treatment were included in the study. The patients were divided into two groups: 8 in the control group and 12 in the study group. Three-dimensional digital models were taken just before canine distalization and after space closure using the 3Shape TRIOS® R700 (3Shape Inc., Copenhagen, Denmark) device. Linear measurements between molars and canines were evaluated. The results were assessed with SPSS 23.0 program (IBM, Armonk, NY, USA).

RESULTS

One subject was excluded from the study group due to insufficient oral hygiene and poor patient compliance. Tooth movement rates were 1.06 mm/month for mandibular and maxillary canine teeth in the control group. In the study group, tooth movement rates were 1.24 mm/month for maxillary canines and 1.09 mm/month for mandibular canines. These differences were not statistically significant (p > 0.05).

CONCLUSION

AcceleDent® Aura is an easy-to-use device; however, in our study its application did not have any positive effects on canine retraction rates.

Accuracy of 3D digital modeling of dental arches

OBJECTIVE

The aim of the study was to verify and compare the accuracy of full-arch digital impressions obtained using two intraoral scanners and three scanning methodologies.

METHODS

A resin model created with dental 3-D printing was scanned by a reference scanner (Zfx Evolution - Zimmer Biomet, Palm Beach Gardens, FL) in order to obtain a 3D reference; the same resin model was then scanned with two different intraoral scanners (Zfx IntraScan and Carestream 3600 - CS 3600®, Carestream, Rochester, NY, USA) using: Technique A (from tooth #27 up to tooth #17); Technique B (from tooth #11 up to tooth #17 and then from tooth #21 up to tooth #27) and Technique C (from tooth #22 up to tooth #17, and then from tooth #12 up to tooth #27 - the MeshLab software v. 1.3.3 was then used to match the two scans). The scans obtained were superimposed over the reference scan by means of a software, and the volumetric discrepancies were calculated.

RESULTS

The mean results for the Zfx Intrascan scanner were: Technique A = 302.47 ± 37.42 µm; Technique B = 180.45 ± 29.86 µm; Technique C = 147.34 ± 28.23 µm. The mean results for the Carestream 3600 scanner were: Technique A = 303.59 ± 40.20 µm; Technique B = 181.53 ± 29.61 µm; Technique C = 142.28 ± 35.33 µm. Technique C, used by both scanners, produced less volumetric discrepancies compared to the other techniques.

CONCLUSIONS

The scanning technique had a statistically significant effect on the quality of the scan (p< 0.0001), whereas the scanner did not present any significant influence (p= 0.91).

Virtual setup in orthodontics: planning and evaluation

OBJECTIVES

The purpose of this study was to evaluate the clinical accuracy of virtual orthodontic setups by using a new CBCT-based approach.

MATERIALS AND METHODS

Ten patients who underwent pre-surgical orthodontics were included in this study. Pre-treatment and pre-surgical cone-beam CT (CBCT) scans and digital dental models were available. The pre-treatment digital dental model was used to create an orthodontic virtual setup. The digital dental models were fused with the corresponding CBCT scans, and the two CBCT scans were aligned using voxel-based matching. Moving each individual tooth from the virtual setup to the final outcome allows the calculation of the accuracy of the virtual setup by using an iterative closest point algorithm. Differences between virtual setup and final outcome were recorded as well as the ICC between two observers.

RESULTS

The inter-observer variability showed a high level of agreement between the observers. The largest mean difference between observers was found in the cranial/caudal direction (0.36 ± 0.30 mm) and the roll rotation (1.54 ± 0.98°). Differences between the virtual setup and final outcome were small in the translational direction (0.45 ± 0.48 mm). Rotational mean differences were larger with the pitch of the incisors (0.00 ± 7.97°) and molars (0.01 ± 10.26°) as largest difference. Excessive extrusion of all upper teeth and more anterior movement than planned were seen for both upper and lower arch. Lower molars showed less extrusion.

CLINICAL RELEVANCE

The data of this study can be used to obtain more insight in the accuracy and achievability of orthodontic virtual setup. Tooth movement can now be studied in more details which can lead to new insights.

3D CBCT human adult odontometrics: Comparative assessment in Saudi, Jordan and Egypt population

OBJECTIVES

To inspect the human adult odontometrics by the assistance of 3D cone beam computerized tomography (CBCT) imaging in Saudi, Jordan and Egypt population.

MATERIALS AND METHODS

Data of this cross sectional study from 252 subject were analysed by 3D CBCT volumetric data in college of dentistry, Aljouf University, from December 2016 to May 2017. All measurements were done by 3D on demand software. The tooth size from 2nd molar to 2nd molar of maxillary and mandibular arch was measured. Independent t test and ANOVA were used to examine the differences between gender and among Arabic population (Saudi, Jordan and Egypt) on the all tooth size.

RESULTS

Comparison between the right and left side odontometrics were significantly dissimilar in 9 out of 14 pairs (p < 0.05). The odontometrics of the 2nd molar to 2nd molar tooth of maxillary and mandibular arch between gender and among Saudi, Jordan and Egypt population were insignificant (p > 0.05).

CONCLUSION

3D CBCT imaging permits us to measure the tooth size effectively and accurately. Based on results, significant asymmetry was revealed in 9 out of 14 pairs in relation to side disparities. No significant differences in tooth size between gender and among races were found. CBCT can elevate the record keeping problem, human adult odontometrics for the analysis can be obtained directly from the digital image.

[Fabrication and accuracy research on 3D printing dental model based on cone beam computed tomography digital modeling]

OBJECTIVE

The aim of this study is to build a digital dental model with cone beam computed tomography (CBCT), to fabricate a virtual model via 3D printing, and to determine the accuracy of 3D printing dental model by comparing the result with a traditional dental cast.

METHODS

CBCT of orthodontic patients was obtained to build a digital dental model by using Mimics 10.01 and Geomagic studio software. The 3D virtual models were fabricated via fused deposition modeling technique (FDM). The 3D virtual models were compared with the traditional cast models by using a Vernier caliper. The measurements used for comparison included the width of each tooth, the length and width of the maxillary and mandibular arches, and the length of the posterior dental crest.

RESULTS

3D printing models had higher accuracy compared with the traditional cast models. The results of the paired t-test of all data showed that no statistically significant difference was observed between the two groups (P>0.05).

CONCLUSIONS

Dental digital models built with CBCT realize the digital storage of patients' dental condition. The virtual dental model fabricated via 3D printing avoids traditional impression and simplifies the clinical examination process. The 3D printing dental models produced via FDM show a high degree of accuracy. Thus, these models are appropriate for clinical practice.

Anterior teeth root inclination prediction derived from digital models: A comparative study of plaster study casts and CBCT images

BACKGROUND

To assess the accuracy of digital models generated using commercially available software to predict anterior teeth root inclination characteristics and compare the results to relevant data obtained from CBCT images.

MATERIAL AND METHODS

Following sample size calculation and after application of inclusion and exclusion criteria, pre-treatment maxillary and mandibular plaster models and the corresponding CBCT scans of 31 patients attending a private orthodontic clinic were selected. The subjects were 10 males and 21 females with age range 12 to 40 years. Plaster models were scanned using the high resolution mode of an Ortho Insight 3D scanner and CBCT scans were taken using a Kodak 9500 Cone Beam 3D System machine. The teeth on the digital scans were segmented and virtual roots were predicted and constructed by the Ortho Insight 3D software. The long axes of the predicted roots and the actual roots, as segmented from the CBCT images, were computed using best-fit lines. The inter-axis angle was used to assess error in root inclination prediction by the software. Mann-Whitney and Kruskal-Wallis tests were used. Intra-examiner error was evaluated using the Bland-Altman method.

RESULTS

The maximum disparity in angle between images derived from digital models and CBCT data was almost 40 degrees (upper left canine). The upper and lower canines produced the worst results, followed by the lower lateral incisors. The upper central incisors showed the best results, although the maximum angle of difference exceeded 20 degrees (with the median around 8 degrees).

CONCLUSIONS

Root morphology imaging prediction is not a primary function of this software and this study confirmed its limitation as a sole tool in routine clinical applications. At present these predictions cannot be considered accurate or reliable unless correlated clinically with a radiographic image. Key words:Digital models, CBCT, tooth root inclination prediction software.

Dental measurements and Bolton index reliability and accuracy obtained from 2D digital, 3D segmented CBCT, and 3d intraoral laser scanner

Background

To compare the reliability and accuracy of direct and indirect dental measurements derived from two types of 3D virtual models: generated by intraoral laser scanning (ILS) and segmented cone beam computed tomography (CBCT), comparing these with a 2D digital model.

Material and Methods

One hundred patients were selected. All patients’ records included initial plaster models, an intraoral scan and a CBCT. Patients´ dental arches were scanned with the iTero® intraoral scanner while the CBCTs were segmented to create three-dimensional models. To obtain 2D digital models, plaster models were scanned using a conventional 2D scanner. When digital models had been obtained using these three methods, direct dental measurements were measured and indirect measurements were calculated. Differences between methods were assessed by means of paired t-tests and regression models. Intra and inter-observer error were analyzed using Dahlberg´s d and coefficients of variation.

Results

Intraobserver and interobserver error for the ILS model was less than 0.44 mm while for segmented CBCT models, the error was less than 0.97 mm. ILS models provided statistically and clinically acceptable accuracy for all dental measurements, while CBCT models showed a tendency to underestimate measurements in the lower arch, although within the limits of clinical acceptability.

Conclusions

ILS and CBCT segmented models are both reliable and accurate for dental measurements. Integration of ILS with CBCT scans would get dental and skeletal information altogether.

Key words:CBCT, intraoral laser scanner, 2D digital models, 3D models, dental measurements, reliability.

Cone Beam Computed Tomographic imaging in orthodontics

Over the last 15 years, cone beam computed tomographic (CBCT) imaging has emerged as an important supplemental radiographic technique for orthodontic diagnosis and treatment planning, especially in situations which require an understanding of the complex anatomic relationships and surrounding structures of the maxillofacial skeleton. CBCT imaging provides unique features and advantages to enhance orthodontic practice over conventional extraoral radiographic imaging. While it is the responsibility of each practitioner to make a decision, in tandem with the patient/family, consensus-derived, evidence-based clinical guidelines are available to assist the clinician in the decision-making process. Specific recommendations provide selection guidance based on variables such as phase of treatment, clinically-assessed treatment difficulty, the presence of dental and/or skeletal modifying conditions, and pathology. CBCT imaging in orthodontics should always be considered wisely as children have conservatively, on average, a three to five times greater radiation risk compared with adults for the same exposure. The purpose of this paper is to provide an understanding of the operation of CBCT equipment as it relates to image quality and dose, highlight the benefits of the technique in orthodontic practice, and provide guidance on appropriate clinical use with respect to radiation dose and relative risk, particularly for the paediatric patient.

Accuracy of Three-dimensional Cone Beam Computed Tomography Digital Model Measurements Compared with Plaster Study Casts

Purpose

The purpose of this study was to assess the accuracy of three-dimensional (3D) cone beam computed tomography (CBCT) study casts by comparing with direct measurements taken from plaster study casts.

Materials and Methods

The dental arches of 30 patient subjects were imaged with a Kodak 9300 3D CBCT devise; Anatomodels were created and in vivo 5 imaging software was used to measure 10 dental arch variables which were compared to measurements of plaster study casts.

Results:

Three of the 10 variables, i.e., overbite, maxillary intermolar width, and arch length, were found significantly smaller (P < 0.05) using the Anatomodels following nonparametric Wilcoxon signed-rank testing. None of the differences found in the study averaged <0.5 mm.

Conclusions

3D CBCT imaging provided clinically acceptable accuracy for dental arch analysis. 3D CBCT imaging tended to underestimate the actual measurement compared to plaster study casts.

A Novel Approach to Determine the Prevalence of Type of Soft Palate Using Digital Intraoral Impression

Aim

To determine the prevalence of type of soft palate in targeted population.

Materials and Methods

Using computer technology in dentistry, intraoral digital scanner, and 3D analysis software tool, study was conducted. 100 patients selected from the outpatient clinics were divided into two groups based on the ages of 20–40 years and 41–60 years with equal ratio of males and females. Each selected patient's maxillary arch was scanned with intraoral scanner; images so obtained were sectioned in anteroposterior cross section and with the 3D analysis software; the angulation between hard and soft palate was determined.

Results

The prevalence of type II soft palate (angulation between hard and soft palate is between 10 and 45 degrees) was highest, 60% in group 1 and 44% in group 2. The difference between genders was statistically significant with p value <0.05 in both the groups, although females had higher angulation compared to the males in all classes of both groups.

Conclusions

In targeted population of Aseer Province, Saudi Arabia, the prevalence of type II soft palate was more common, with higher soft palate angulation among females. The advanced age had no effect in the type of soft palate in the region.

Accuracy and reproducibility of dental measurements on tomographic digital models: a systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review with meta-analysis was to assess the accuracy and reproducibility of dental measurements obtained from digital study models generated from CBCT compared with those acquired from plaster models.

METHODS

The electronic databases Cochrane Library, Medline (via PubMed), Scopus, VHL, Web of Science, and System for Information on Grey Literature in Europe were screened to identify articles from 1998 until February 2016. The inclusion criteria were: prospective and retrospective clinical trials in humans; validation and/or comparison articles of dental study models obtained from CBCT and plaster models; and articles that used dental linear measurements as an assessment tool. The methodological quality of the studies was carried out by Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. A meta-analysis was performed to validate all comparative measurements.

RESULTS

The databases search identified a total of 3160 items and 554 duplicates were excluded. After reading titles and abstracts, 12 articles were selected. Five articles were included after reading in full. The methodological quality obtained through QUADAS-2 was poor to moderate. In the meta-analysis, there were statistical differences between the mesiodistal widths of mandibular incisors, maxillary canines and premolars, and overall Bolton analysis. Therefore, the measurements considered accurate were maxillary and mandibular crowding, intermolar width and mesiodistal width of maxillary incisors, mandibular canines and premolars, in both arches for molars.

CONCLUSIONS

Digital models obtained from CBCT were not accurate for all measures assessed. The differences were clinically acceptable for all dental linear measurements, except for maxillary arch perimeter. Digital models are reproducible for all measurements when intraexaminer assessment is considered and need improvement in interexaminer evaluation.

Accuracy of stereolithographically printed digital models compared to plaster models

OBJECTIVE

This study compared the accuracy of plaster models from alginate impressions and printed models from intraoral scanning.

MATERIALS AND METHODS

A total of 28 volunteers were selected and alginate impressions and intraoral scans were used to make plaster models and digital models of their dentition, respectively. The digital models were printed using a stereolithographic (SLA) 3D printer with a horseshoe-shaped design. Two calibrated examiners measured distances on the plaster and printed models with a digital caliper. The paired t test was used to determine intraobserver error and compare the measurements. The Pearson correlation coefficient was used to evaluate the reliability of measurements for each model type.

RESULTS

The measurements on plaster models and printed models show some significant differences in tooth dimensions and interarch parameters, but these differences were not clinically relevant, except for the transversal measurements. The upper and lower intermolar distances on the printed models were statistically significant and clinically relevant smaller.

CONCLUSIONS

Printed digital models with the SLA 3D printer studied, with a horseshoe-shaped base made from intraoral scans cannot replace conventional plaster models from alginate impressions in orthodontics for diagnosis and treatment planning because of their clinically relevant transversal contraction.

Accuracy and reproducibility of measurements on plaster models and digital models created using an intraoral scanner

AIM

The purpose of the present study was to evaluate the accuracy and reproducibility of measurements made on digital models created using an intraoral color scanner compared to measurements on dental plaster models.

METHODS

This study included impressions of 28 volunteers. Alginate impressions were used to make plaster models, and each volunteers' dentition was scanned with a TRIOS Color intraoral scanner. Two examiners performed measurements on the plaster models using a digital caliper and measured the digital models using Ortho Analyzer software. The examiners measured 52 distances, including tooth diameter and height, overjet, overbite, intercanine and intermolar distances, and the sagittal relationship. The paired t test was used to assess intra-examiner performance and measurement accuracy of the two examiners for both plaster and digital models. The level of clinically relevant differences between the measurements according to the threshold used was evaluated and a formula was applied to calculate the chance of finding clinically relevant errors on measurements on plaster and digital models.

RESULTS

For several parameters, statistically significant differences were found between the measurements on the two different models. However, most of these discrepancies were not considered clinically significant. The measurement of the crown height of upper central incisors had the highest measurement error for both examiners. Based on the interexaminer performance, reproducibility of the measurements was poor for some of the parameters.

CONCLUSIONS

Overall, our findings showed that most of the measurements on digital models created using the TRIOS Color scanner and measured with Ortho Analyzer software had a clinically acceptable accuracy compared to the same measurements made with a caliper on plaster models, but the measuring method can affect the reproducibility of the measurements.

The Accuracy and Reproducibility of Linear Measurements Made on CBCT-derived Digital Models

OBJECTIVE

To evaluate the accuracy and reproducibility of linear measurements made on cone-beam computed tomography (CBCT)-derived digital models.

MATERIALS AND METHODS

A total of 25 patients (44% female, 18.7 ± 4 years) who had CBCT images for diagnostic purposes were included. Plaster models were obtained and digital models were extracted from CBCT scans. Seven linear measurements from predetermined landmarks were measured and analyzed on plaster models and the corresponding digital models. The measurements included arch length and width at different sites. Paired t test and Bland-Altman analysis were used to evaluate the accuracy of measurements on digital models compared to the plaster models. Also, intraclass correlation coefficients (ICCs) were used to evaluate the reproducibility of the measurements in order to assess the intraobserver reliability.

RESULTS

The statistical analysis showed significant differences on 5 out of 14 variables, and the mean differences ranged from -0.48 to 0.51 mm. The Bland-Altman analysis revealed that the mean difference between variables was (0.14 ± 0.56) and (0.05 ± 0.96) mm and limits of agreement between the two methods ranged from -1.2 to 0.96 and from -1.8 to 1.9 mm in the maxilla and the mandible, respectively. The intraobserver reliability values were determined for all 14 variables of two types of models separately. The mean ICC value for the plaster models was 0.984 (0.924-0.999), while it was 0.946 for the CBCT models (range from 0.850 to 0.985).

CONCLUSION

Linear measurements obtained from the CBCT-derived models appeared to have a high level of accuracy and reproducibility.

Accuracy of Bolton analysis measured in laser scanned digital models compared with plaster models (gold standard) and cone-beam computer tomography images

OBJECTIVE

The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models.

METHODS

CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC).

RESULTS

Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were 0.41 ± 0.305% and 0.45 ± 0.456%, respectively; for anterior Bolton ratios, 0.59 ± 0.520% and 1.01 ± 0.780%, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis.

CONCLUSIONS

Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis.

Update on cone beam technology and orthodontic analysis

Orthodontics and cone beam computed tomography technology have evolved tremendously in the last 10 years. The technology has evolved from a predominantly diagnostic entity to a true clinical and translational product. One can believe that this technology is here to stay and it has a real role to revolutionize the efficiency and effectiveness of orthodontic care. This article discusses the current advancements and use of cone beam computed tomography.

Reliability of measurements made on scanned cast models using the 3 Shape R 700 scanner

OBJECTIVES

In dentistry, the latest technological advancements have been incorporated primarily into diagnostic tools such as virtual dental models. The aim of this study was to evaluate the reliability of measurements made on digital cast models scanned in the 3 Shape R 700 scanner (3 Shape, Copenhagen, Denmark) that uses a non-destructive laser beam to reproduce model surfaces so that the plaster model is not destroyed.

METHODS

The sample consisted of 26 cast models, and 6 linear measurements were made on the cast models and compared with the same measurements on digital models. The measurements assessed were: (1) distance between mandibular canines; (2) distance between mandibular molars; (3) distance between canine and maxillary molar; (4) buccal-lingual diameter of maxillary central incisor; (5) distance between two points of the incisive papillae of maxillary and mandibular central incisors; and (6) distance between the buccal surface of the maxillary central incisor and the buccal surface of the mandibular antagonist (overjet). The Student's t-test or Wilcoxon test was used at 5% and the Lin's concordance test at 95% confidence interval.

RESULTS

The overjet measurement was the only one that showed a statistically significant difference (p < 0.05). A high level of concordance was found for all measurements.

CONCLUSIONS

The digital models obtained from the 3 Shape R 700 scanner are reliable and can be considered an alternative to cast models for performing measurements and analyses in orthodontic practice.

Evaluation of dental morphometrics during the orthodontic treatment

BACKGROUND

Diagnostic orthodontic and prosthetic procedures commence with an initial examination, during which a number of individual findings on occlusion or malocclusion are clarified. Nowadays we try to replace standard plaster casts by scanned objects and digital models.

METHOD

Geometrically calibrated images aid in the comparison of several different steps of the treatment and show the variation of selected features belonging to individual biomedical objects. The methods used are based on geometric morphometrics, making a new approach to the evaluation of the variability of features. The study presents two different methods of measurement and shows their accuracy and reliability.

RESULTS

The experimental part of the present paper is devoted to the analysis of the dental arch objects of 24 patients before and after the treatment using the distances between the canines and premolars as the features important for diagnostic purposes. Our work proved the advantage of measuring digitalized orthodontic models over manual measuring of plaster casts, with statistically significant results and accuracy sufficient for dental practice.

CONCLUSION

A new method of computer imaging and measurements of a dental stone cast provides information with the precision required for orthodontic treatment. The results obtained point to the reduction in the variance of the distances between the premolars and canines during the treatment, with a regression coefficient RC=0.7 and confidence intervals close enough for dental practice. The ratio of these distances pointed to the nearly constant value of this measure close to 0.84 for the given set of 24 individuals.

Comparison of 3-dimensional dental models from different sources: diagnostic accuracy and surface registration analysis

INTRODUCTION

The aim of this study was to assess the diagnostic accuracy and surface matching characteristics of 3-dimensional digital dental models obtained from various sources.

METHODS

Three sets of maxillary and mandibular digital models of 30 subjects were included in this study. Three-dimensional stereolithography model files were obtained from a 3-dimensional laser desktop scanner (Ortho-Insight 3D; Motionview Software, Hixson, Tenn), the emodel system (GeoDigm, Chanhassen, Minn), and cone-beam computerized tomography. Arch-length discrepancy measurements were made on the 3-dimensional digital models and compared with direct caliper measurements. Additionally, stereolithography files from the 3 digital model systems were paired and superimposed using a best-fit algorithm. Average linear differences between the stereolithography shells were computed together with surface correlation amounts at various tolerance levels. Data were evaluated using intraclass correlation coefficients and the Tukey mean difference test.

RESULTS

Although all 3 digital model groups displayed good correlation with caliper measurements, the virtual scan models had the highest correlation with the manual method (ICC > 0.95). The Tukey mean difference test showed no consistent bias of one approach vs the others compared with caliper measurements; random errors were detected in all the comparisons. For the estimation of arch-length discrepancy, the mean bias of the scanned virtual models in comparison with caliper measurements (0.24 ± 0.67 mm) was smaller than the mean biases of the emodels and the models generated from cone-beam computed tomography. Additionally, the best surface overlap correlation was observed between the virtual scanned models and the emodels. The mean linear distances between the stereolithography shells of these 2 model systems were 0.14 and 0.13 mm for the maxillary and mandibular arches, respectively.

CONCLUSIONS

All 3 digital model systems can provide diagnostic information similar to caliper measurements, with varying degrees of agreement limits. The scanned virtual models had the least mean bias. A strong surface match correlation was observed between the virtual scanned models and the emodels, indicating that these could be used interchangeably.

Accuracy of laser-scanned models compared to plaster models and cone-beam computed tomography

OBJECTIVE

To compare the accuracy of measurements obtained from the three-dimensional (3D) laser scans to those taken from the cone-beam computed tomography (CBCT) scans and those obtained from plaster models.

MATERIALS AND METHODS

Eighteen different measurements, encompassing mesiodistal width of teeth and both maxillary and mandibular arch length and width, were selected using various landmarks. CBCT scans and plaster models were prepared from 60 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner, and the selected landmarks were measured using its software. CBCT scans were imported and analyzed using the Avizo software, and the 26 landmarks corresponding to the selected measurements were located and recorded. The plaster models were also measured using a digital caliper. Descriptive statistics and intraclass correlation coefficient (ICC) were used to analyze the data.

RESULTS

The ICC result showed that the values obtained by the three different methods were highly correlated in all measurements, all having correlations>0.808. When checking the differences between values and methods, the largest mean difference found was 0.59 mm±0.38 mm.

CONCLUSIONS

In conclusion, plaster models, CBCT models, and laser-scanned models are three different diagnostic records, each with its own advantages and disadvantages. The present results showed that the laser-scanned models are highly accurate to plaster models and CBCT scans. This gives general clinicians an alternative to take into consideration the advantages of laser-scanned models over plaster models and CBCT reconstructions.

The validity, reliability, and time requirement of study model analysis using cone-beam computed tomography-generated virtual study models

OBJECTIVES

To investigate the validity, reliability, and time spent to perform a full orthodontic study model analysis (SMA) on cone-beam computed tomography (CBCT)-generated dental models (Anatomodels) compared with conventional plaster models and a subset of extracted premolars.

SETTING AND SAMPLE POPULATION

A retrospective sample of 30 consecutive patient records with fully erupted permanent dentition, good-quality plaster study models, and CBCT scans. Twenty-two extracted premolars were available from eleven of these patients.

MATERIALS AND METHODS

Five evaluators participated in the inter-rater reliability study and one evaluator for the intrarater reliability and validity studies. Agreement was assessed by ICC and cross-tabulations, while mean differences were investigated using paired-sample t-tests and repeated-measures anova.

RESULTS

For all three modalities studied, intrarater reliability was excellent, inter-rater reliability was moderate to excellent, validity was poor to moderate, and performing SMA on Anatomodels took twice as long as on plaster.

CONCLUSIONS

Study model analysis using CBCT-generated study models was reliable but not always valid and required more time to perform when compared with plaster models.

CBCT in orthodontics: the wave of future

Cone beam computed tomography (CBCT) has probably been one of the most revolutionary innovations in the field of dentistry in the past decade and it provides a novel platform for orthodontic diagnosis and treatment planning. Current imaging techniques are essentially two-dimensional (2D) representations of threedimensional (3D) objects and suffer from several limitations. Hence, fulfillment of ideal imaging goals has been limited. Twodimensional radiographs are insufficient, especially in complex cases like impacted teeth, supernumerary teeth and orthognathic surgeries. CBCT images provide far more detailed information than conventional 2D radiographs and are user friendly. Soft tissues, skull, airway and the dentition can be observed and measured on CBCT images in a 1:1 ratio.

CLINICAL SIGNIFICANCE

CBCT provides an excellent tool for accurate diagnosis, more predictable treatment planning, more efficient patient management and education, improved treatment outcome and patient satisfaction. This article focuses on various applications of cone beam CT technology in orthodontics.

Mandibular anterior bony support and incisor crowding: Is there a relationship?

INTRODUCTION

The aim of this study was to test the null hypothesis that increased irregularity of the mandibular incisors is associated with a reduction in the alveolar support on cone-beam computed tomographic sections.

METHODS

From a sample of 1100 digital volumetric tomographs, 125 tomographs of subjects with Class I malocclusion (mean age, 21.6 ± 4.8 years) were selected for this study. An irregularity index was used to categorize these tomographs as having mild, moderate, or severe crowding. All tomographs were taken by using an iCAT (Imaging Sciences International, Hatfield, Pa) imaging device. The following parameters were measured on the sections corresponding to the 4 mandibular incisors with the iCAT software: height, thickness, and area of the entire symphysis; height, thickness, and area of the cancellous bone of the symphysis; and distance between the vestibular and lingual cortices. For the statistical evaluation, independent samples t test, analysis of variance, and the Tukey HSD test were used at an alpha level 0.05. The Pearson correlation coefficient and a simple linear regression were calculated to determine the relationship between mandibular anterior bony support and incisor crowding.

RESULTS

Almost all mandibular anterior bone measurements were greater in the male subjects than in the female subjects (height of the mandibular symphysis, P <0.001; cancellous bone height, P <0.001). Female subjects with mild crowding had higher values for cancellous bone height (P = 0.025) and vestibular cancellous bone thickness (P = 0.004) than did those with severe crowding. However, no differences were detected in the male subjects. Additionally, significant correlations were determined between incisor crowding and thickness of the mandibular symphysis, cancellous bone thickness, and the vestibular part of cancellous bone thickness in female subjects.

CONCLUSIONS

Significant relationships were found between the measures of mandibular incisor crowding and basal bone dimensions in female subjects. Except for the vestibular part of cancellous bone thickness, all mandibular incisor bone measurements were greater in the male subjects than in the female subjects.

Evaluation of the validity of the Bolton Index using cone-beam computed tomography (CBCT)

AIMS

To evaluate the reliability and reproducibility of calculating the Bolton Index using cone-beam computed tomography (CBCT), and to compare this with measurements obtained using the 2D Digital Method.

MATERIAL AND METHODS

Traditional study models were obtained from 50 patients, which were then digitized in order to be able to measure them using the Digital Method. Likewise, CBCTs of those same patients were undertaken using the Dental Picasso Master 3D® and the images obtained were then analysed using the InVivoDental programme.

RESULTS

By determining the regression lines for both measurement methods, as well as the difference between both of their values, the two methods are shown to be comparable, despite the fact that the measurements analysed presented statistically significant differences.

CONCLUSIONS

The three-dimensional models obtained from the CBCT are as accurate and reproducible as the digital models obtained from the plaster study casts for calculating the Bolton Index. The differences existing between both methods were clinically acceptable.

Surface analysis of study models generated from OrthoCAD and cone-beam computed tomography imaging

INTRODUCTION

The purpose of this research was to determine the accuracy of digital models generated by cone-beam computed tomography and compare it with that of OrthoCAD models (Cadent, Carlstadt, NJ) for orthodontic diagnosis and treatment planning by using surface area analysis.

MATERIALS

Two sets of maxillary and mandibular digital models of 30 subjects were obtained. The models were made from impressions scanned with OrthoCAD and by conversion of related cone-beam computed tomography files. Each patient's matched pairs of maxillary and mandibular models were superimposed by using a software program and a best-fit algorithm; surface-to-surface analysis was then performed. The average linear differences between the 2 files at all points on the surfaces were measured, and tolerance levels of 0.25, 0.5, 0.75, 1.0, 1.25, and 1.5 mm were set to determine the surface correlation amounts between the 2 files. Additionally, 6 linear measurements from predetermined landmarks were also measured and analyzed.

RESULTS

The average maxillary model linear difference was 0.28 to 0.60 mm, whereas the average mandibular model linear difference ranged between 0.34 and 0.61 mm. Greater than a 90% surface correlation was obtained on average at 1.00 mm in the maxillary models and at 1.25 mm in the mandibular models. The mean differences obtained from the linear measurements of the maxillary and mandibular models were 0.071 and 0.018 mm, respectively.

CONCLUSIONS

Surface-to-surface analysis of OrthoCAD and digital models generated by cone-beam computed tomography pointed to a fair overlap between the protocols. The accuracy of digital models generated by cone-beam computed tomography is adequate for initial diagnosis and treatment planning in orthodontics.

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.

Creation of the virtual patient for the study of facial morphology

The author provides an overview of the new imaging technologies that allow the practitioner to accurately capture the patient's soft tissue facial morphology and underlying bones and teeth, including details of dental model integration. This article describes how a virtual patient is created and manipulated and the practical use of this technology. It takes the quantification of the 3D surface further by proposing a reference framework of landmarks of craniofacial structure that can be used for comparison of surgical change, growth, gender, and phenotype.

Three-dimensional assessment of pharyngeal airway in nasal- and mouth-breathing children

OBJECTIVES

The aim of this study was to assess the pharyngeal airway space (PAS) in nasal and mouth-breathing children using cone beam computed tomography (CBCT).

METHODS

Volume, area, minimum axial area and linear measurements (PAS-NL, PAS-UP, PAS-OccL, PAS-UT, PAS-Bgo, PAS-ML, PAS-TP) of the pharyngeal airway of 50 children (mean age 9.16 years) were obtained from the CBCT images. The means and standard deviations were compared according to sexes (28 male and 22 female) and breathers patterns (25 nasal breathers and 25 mouth breathers).

RESULTS

There were no statistically significant differences (p>0.05) between all variables when compared by sexes. Comparisons between nasal and mouth breathers showed significant differences only in two linear measurements: PAS-OccL (p<0.001) and PAS-UP (P<0.05). Airway volume (p<0.001), area (p<0.001) and minimum axial area (p<0.01) had significant differences between the groups.

CONCLUSIONS

The CBCT evaluation showed that pharyngeal airway dimensions were significantly greater in nasal-breathers than in mouth-breathers.