Helping general dental practitioners use the Index of Orthodontic Treatment Need: an assessment of available educational apps

Introduction The Index of Orthodontic Treatment Need (IOTN) defines who receives treatment on the NHS. The British Orthodontic Society developed the 'Easy IOTN' app to help the dental team use IOTN more effectively.Aim This study aims to investigate the quality of the 'Easy IOTN' app and any alternative mobile apps developed to aid a dentist's ability to use IOTN.Materials and methods The App Store and Google Play were searched to identify available apps which provide an educational resource for IOTN. Any app identified was assessed using the Mobile App Rating Scale (MARS) and the Royal College of Physicians' health informatics unit checklist. The 'Easy IOTN' app continuous professional development (CPD) section was assessed for accuracy using a focus group.Results Only the 'Easy IOTN' app was identified. It has a mean MARS score of 3.6. Significant inaccuracies were found within the CPD component of the 'Easy IOTN' app.Discussion A mean MARS score of 3.6 is deemed average and is comparable to the quality of other orthodontic apps which exist. Errors contained within the CPD component could confuse users and have a negative impact on IOTN skill development.Conclusions The educational component of the 'Easy IOTN' app is of an acceptable standard, but the CPD section is flawed.

Accuracy and reliability of measurements performed using two different software programs on digital models generated using laser and computed tomography plaster model scanners

Objective

The aim of this study was to compare the accuracy and reliability of measurements performed using two different software programs on digital models generated using two types of plaster model scanners (a laser scanner and a computed tomography [CT] scanner).

Methods

Thirty plaster models were scanned with a 3Shape laser scanner and with a Flash CT scanner. Two examiners performed measurements on plaster models by using digital calipers and on digital models by using Ortho Analyzer (3Shape) and Digimodel® (OrthoProof) software programs. Forty-two measurements, including tooth diameter, crown height, overjet, overbite, intercanine and intermolar distances, and sagittal relationship, were obtained.

Results

Statistically significant differences were not found between the plaster and digital model measurements (ANOVA); however, some discrepancies were clinically relevant. Plaster and digital model measurements made using the two scanning methods showed high intraclass coefficient correlation values and acceptable 95% limits of agreement in the Bland-Altman analysis. The software used did not influence the accuracy of measurements.

Conclusions

Digital models generated from plaster casts by using laser and CT scanning and measured using two different software programs are accurate, and the measurements are reliable. Therefore, both fabrication methods and software could be used interchangeably.

Digital Models as an Alternative to Plaster Casts in Assessment of Orthodontic Treatment Outcomes

Objective

This study aimed to compare the use of digital models and plaster casts in assessing the improvement in occlusion following orthodontic treatment.

Materials and Methods

Digital models and plaster casts of 39 consecutive patients at pre- and posttreatment stages were obtained and assessed using the Peer Assessment Rating (PAR) index and the Index of Complexity and Treatment Need (ICON). PAR and ICON scores were compared at individual and group levels. Categorization of improvement level was compared using Kappa (κ) statistics.

Results

There was no significant difference in neither PAR scores (p > 0.05) nor ICON scores (p > 0.05) between digital and plaster cast assessments. The Intraclass Correlation Coefficient (ICC) values for changes in PAR and ICON scores were excellent (ICC > 0.80). Agreement of ratings of occlusal improvement level between digital and plaster model assessments was 0.83 (κ) for PAR and 0.59 (κ) for ICON, respectively.

Conclusion

The study supported the use of digital models as an alternative to plaster casts when assessing changes in occlusion at the ‘individual patient' level using ICON or PAR. However, it could not fully support digital models as an alternate to plaster casts at ‘the group level' (as in the case of clinical audit/research).

Palatal volume and area assessment on digital casts generated from cone-beam computed tomography scans

OBJECTIVES

The objective of this study was to develop a reproducible method to measure the change of palatal volume and area through superimposition using maxillary expansion digital cast models.

MATERIALS AND METHODS

A total of 10 pre- and 10 postexpansion dental cast models were scanned by the same cone-beam computed tomography machine. Superimposition was performed using a fully automated surface-best fit of the palatal surfaces on the digital cast models. A gingival plane, identified only once on superimposed casts, and a distal plane with the lateral closing border and the palatal surface were used to localize this selection of air. Area and volume were calculated for pre- and postexpansion records. Pre- and postexpansion palatal volume and area were measured by the main investigator and three different observers for inter- and intra-observer reproducibility assessment.

RESULTS

The level of intra- and inter-observer agreement was very strong (intraclass correlation coefficients ≥ 0.953; P value < .0001) for all measurements.

CONCLUSIONS

Palatal volume and area measurements based on the proposed superimposition are reproducible and can be used reliably.

Reliability of Bolton analysis evaluation in tridimensional virtual models

Objective:

The present study aimed at evaluating the reliability of Bolton analysis in tridimensional virtual models, comparing it with the manual method carried out with dental casts.

Methods:

The present investigation was performed using 56 pairs of dental casts produced from the dental arches of patients in perfect conditions and randomly selected from Universidade Federal da Bahia, School of Dentistry, Orthodontics Postgraduate Program. Manual measurements were obtained with the aid of a digital Cen-Tech 4"^(r) caliper (Harpor Freight Tools, Calabasas, CA, USA). Subsequently, samples were digitized on 3Shape^(r) R-700T scanner (Copenhagen, Denmark) and digital measures were obtained by Ortho Analyzer software.

Results:

Data were subject to statistical analysis and results revealed that there were no statistically significant differences between measurements with p-values equal to p = 0.173 and p= 0.239 for total and anterior proportions, respectively.

Conclusion:

Based on these findings, it is possible to deduce that Bolton analysis performed on tridimensional virtual models is as reliable as measurements obtained from dental casts with satisfactory agreement.

Are there differences between comparison methods used to evaluate the accuracy and reliability of digital models?

OBJECTIVES

The accuracy and reliability of plaster models and digital models acquired with two different surface laser scanners were tested by means of three methods: measurement with calipers, digital measurement with proper software and superimposition of the digital models.

METHODS

Thirty plaster models with permanent dentition that met the inclusion criteria were selected and scanned with two laser scanners (R700 and Xcad). Three examiners measured distances on plaster models with a digital caliper and on digital models using Ortho Analyzer software. The digital models were also compared by means of superimposition of the models using the Geomagic Qualify software. The intra and inter-examiner reliability of the measurements were evaluated using the ICC. Paired t test was used to test the accuracy of the measurements on digital and plaster models.

RESULTS

The measurements on plaster and digital models acquired by two different scanners showed high values for the ICC. Although statistically significant differences between the measurements on plaster and digital models have been found, these discrepancies were not considered clinically relevant. The superimposition method with Geomagic Qualify software showed that the two digital models were not significantly different.

CONCLUSIONS

Digital models created from scanned plaster models using the R700 or Xcad scanners were clinically accurate according to the two methods of comparison used.

Optical 3D scans for orthodontic diagnostics performed on full-arch impressions. Completeness of surface structure representation

OBJECTIVE

The purpose of this work was to evaluate the completeness of surface structure representation offered by full-arch impression scans in different situations of tooth (mal)alignment and whether this completeness could be improved by performing rescans on the same impressions reduced sequentially to different levels of gingival height and by adding extra single scans to the number of single scans recommended by the manufacturer.

METHODS

Three pairs of full-arch resin models were used as reference, characterized either by normal occlusion, by anterior diastematic protrusion (and edentulous spaces in the lower posterior segments), or by anterior crowding. An alginate impression of each arch was taken and digitized with a structured-light scanner, followed by three rescans with the impression cut back to 10, 5, and 1 mm of gingival height. Both the initial scan and the rescans were performed both with 19 basic single scans and with 10 extra single scans. Each impression scan was analyzed for quantitative completeness relative to its homologous direct scan of the original resin model. In addition, the topography of voids in the resultant digital model was assessed by visual inspection.

RESULTS

Compared to the homologous reference scans of the original resin models, completeness of the original impression scans--in the absence of both gingival cutback and extra single scans--was 97.23 ± 0.066% in the maxilla or 95.72 ± 0.070% in the mandible with normal occlusion, 91.11 ± 0.132% or 96.07 ± 0.109% in the arches with anterior diastematic protrusion, and 98.24 ± 0.085% or 93.39 ± 0.146% in those with anterior crowding. Gingival cutback and extra single scans were found to improve these values up to 100.35 ± 0.066% or 99.53 ± 0.070% in the arches with normal occlusion, 91.77 ± 0.132% or 97.95 ± 0.109% in those with anterior diastematic protrusion, and 98.59 ± 0.085% or 98.96 ± 0.146% in those with anterior crowding.

CONCLUSION

In strictly quantitative terms, the impression scans did capture relatively large percentages of the total surface. However, the topographic examinations revealed that regions essential for orthodontic model analysis were missing. The malocclusion models were particularly affected. Thus, impression scans performed with structured-light scanners cannot replace scans of positive casts for diagnostic use in orthodontics.

Dimensional accuracy of jaw scans performed on alginate impressions or stone models: A practice-oriented study

OBJECTIVES

Digital jaw models offer more extensive possibilities for analysis than casts and make it easier to share and archive relevant information. The aim of this study was to compare the dimensional accuracy of scans performed on alginate impressions and on stone models to reference scans performed on underlying resin models.

METHODS

Precision spheres 5 mm in diameter were occlusally fitted to the sites of the first premolars and first molars on a pair of jaw models fabricated from resin. A structured-light scanner was used for digitization. Once the two reference models had been scanned, alginate impressions were taken and scanned after no later than 1 h. A third series of scans was performed on type III stone models derived from the impressions. All scans were analyzed by performing five repeated measurements to determine the distances between the various sphere centers.

RESULTS

Compared to the reference scans, the stone-model scans were larger by a mean of 73.6 µm (maxilla) or 65.2 µm (mandible). The impression scans were only larger by 7.7 µm (maxilla) or smaller by 0.7 µm (mandible). Median standard deviations over the five repeated measurements of 1.0 µm for the reference scans, 2.35 µm for the impression scans, and 2.0 µm for the stone-model scans indicate that the values measured in this study were adequately reproducible.

CONCLUSION

Alginate impressions can be suitably digitized by structured-light scanning and offer considerably better dimensional accuracy than stone models. Apparently, however, both impression scans and stone-model scans can offer adequate precision for orthodontic purposes. The main issue of impression scans (which is incomplete representation of model surfaces) is being systematically explored in a follow-up study.

Investigation of the effects of storage time on the dimensional accuracy of impression materials using cone beam computed tomography

PURPOSE

The storage conditions of impressions affect the dimensional accuracy of the impression materials. The aim of the study was to assess the effects of storage time on dimensional accuracy of five different impression materials by cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Polyether (Impregum), hydrocolloid (Hydrogum and Alginoplast), and silicone (Zetaflow and Honigum) impression materials were used for impressions taken from an acrylic master model. The impressions were poured and subjected to four different storage times: immediate use, and 1, 3, and 5 days of storage. Line 1 (between right and left first molar mesiobuccal cusp tips) and Line 2 (between right and left canine tips) were measured on a CBCT scanned model, and time dependent mean differences were analyzed by two-way univariate and Duncan's test (α=.05).

RESULTS

For Line 1, the total mean difference of Impregum and Hydrogum were statistically different from Alginoplast (P<.05), while Zetaflow and Honigum had smaller discrepancies. Alginoplast resulted in more difference than the other impressions (P<.05). For Line 2, the total mean difference of Impregum was statistically different from the other impressions. Significant differences were observed in Line 1 and Line 2 for the different storage periods (P<.05).

CONCLUSION

The dimensional accuracy of impression material is clinically acceptable if the impression material is stored in suitable conditions.

Digital casts in orthodontics: a comparison of 4 software systems

INTRODUCTION

The introduction of digital cast models is inevitable in the otherwise digitized everyday life of orthodontics. The introduction of this new technology, however, is not straightforward, and selecting an appropriate system can be difficult. The aim of the study was to compare 4 orthodontic digital software systems regarding service, features, and usability.

METHODS

Information regarding service offered by the companies was obtained from questionnaires and Web sites. The features of each software system were collected by exploring the user manuals and the software programs. Replicas of pretreatment casts were sent to Cadent (OrthoCAD; Cadent, Carlstadt, NJ), OthoLab (O3DM; OrthoLab, Poznan, Poland), OrthoProof (DigiModel; OrthoProof, Nieuwegein, The Netherlands), and 3Shape (OrthoAnalyzer; 3Shape, Copenhagen, Denmark). The usability of the programs was assessed by experts in interaction design and usability using the "enhanced cognitive walkthrough" method: 4 tasks were defined and performed by a group of domain experts while they were observed by usability experts.

RESULTS

The services provided by the companies were similar. Regarding the features, all 4 systems were able to perform basic measurements; however, not all provided the peer assessment rating index or the American Board of Orthodontics analysis, simulation of the treatment with braces, or digital articulation of the casts. All systems demonstrated weaknesses in usability. However, OrthoCAD and 03DM were considered to be easier to learn for first-time users.

CONCLUSIONS

In general, the usability of these programs was poor and needs to be further developed. Hands-on training supervised by the program experts is recommended for beginners.

The Assessment of Digital Study Models Using the GOSLON Yardstick Index

Objective

To investigate the reproducibility and repeatability of digital models of patients with a unilateral cleft lip and palate (UCLP) using the GOSLON yardstick.

Design

Reproducibility and repeatability study.

Method

Two examiners used the GOSLON yardstick to assess the intermaxillary dentoalveolar relationship of 30 consecutive UCLP patients by analyzing their 9-year (±3 months) dental study casts and digital study models. The records were rated 1 week apart to avoid bias. The process was repeated 1 month later as a measure of reproducibility. Reliability was assessed by comparing the GOSLON score achieved between the two modalities. Patient dental study casts were sent to 3M Unitek Australia to be scanned using the 3M Unitek Lava™ system to produce digital study models. The accuracy of the dental study cast occlusal registration was assessed by both raters prior to sending the study models for scanning.

Statistical analysis

The Linear Weighted Kappa statistic and Kendall's Coefficient of Concordance statistic were used to determine the levels of agreement within and between raters.

Results

The linear weighted Kappa statistic for intrarater repeatability of digital study models scores were very high (0.89 and 0.97). This compared favorably to the intrarater repeatability of study model casts scores (0.86 and 0.97). There was very good agreement for interrater digital study model scores (0.80 and 0.87) and also for the interrater study model casts scores (0.80 and 0.90). Kendall's Coefficient of Concordance statistic (0.99) and Correlation Coefficient (0.86) support the weighted Kappa results of the digital study model scores.

Conclusion

Digital models can be used for GOSLON scoring with a high degree of reproducibility and repeatability.

Linear measurements using virtual study models

OBJECTIVE

To perform a systematic review of the literature to assess the reliability and validity of linear measurements using virtual vs plaster study models.

MATERIALS AND METHODS

A search strategy was developed for four online databases, and references were further hand searched for studies additional papers. Three researchers determined the eligibility of papers by applying specific selection criteria and ultimately selected 17 papers. Grouped by virtual model acquisition type and the number of landmarks used in a given measurement, the data were weighted by sample size and analyzed in terms of the reliability and validity of linear measurements.

RESULTS

The intrarater reliability was high for two-landmark and >two-landmark linear measurements performed on laser-acquired models or cone-beam computed tomography (CBCT)-acquired models and were similar to measurements on plaster models. Validity was high for two-landmark and >two-landmark linear measurements comparing laser-acquired models or CBCT-acquired models to plaster study models, and the weighted mean differences were clinically insignificant. Agreement of measurements was excellent, with less variability than correlation. Acquisition type had no perceived influences on reliability and validity. More than two-landmark measures tended to have higher mean differences than two-landmark measures.

CONCLUSIONS

Virtual study models are clinically acceptable compared with plaster study models with regard to intrarater reliability and validity of selected linear measurements.