A novel method for superimposition and measurements on maxillary digital 3D models—studies on validity and reliability

Ganzer, Niels; Feldmann, Ingalill; Liv, Per; Bondemark, Lars

doi:10.1093/ejo/cjx029

Cited by 45 publications

(37 citation statements)

References 21 publications

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“…Superimposition of the dental models is necessary to evaluate spatial changes in time. For maxillary dental models, superimposition can be performed accurately by utilizing stable reference areas like the palatal rugae [27][28][29]. However, when large tooth movements are performed, for example, in cases of premolar extractions, the palatal rugae might not be stable.…”

Section: Discussionmentioning

confidence: 99%

Virtual setup in orthodontics: planning and evaluation

et al. 2019

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Objectives The purpose of this study was to evaluate the clinical accuracy of virtual orthodontic setups by using a new CBCTbased approach. Materials and methods Ten patients who underwent pre-surgical orthodontics were included in this study. Pre-treatment and presurgical 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.

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Section: Discussionmentioning

confidence: 99%

Virtual setup in orthodontics: planning and evaluation

et al. 2019

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“…Assessments were conducted blindly using the Raw-, Fine matching & Deformation analysis superimposition (RFD). 23 The results showed a mean loss of anchorage during levelling/alignment and space closure of about 1.5 mm for anchorage reinforcement with miniscrews and 3.8 mm for anchorage reinforcement with molar blocks. The difference in anchorage loss occurred mainly during space closure and was statistically significant.…”

Section: Outcome Orthodontic Outcomementioning

confidence: 92%

A cost-effectiveness analysis of anchorage reinforcement with miniscrews and molar blocks in adolescents: a randomized controlled trial

Ganzer

Feldmann

Petrén

et al. 2018

European Journal of Orthodontics

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Objective To analyse cost-effectiveness of anchorage reinforcement with buccal miniscrews and with molar blocks. We hypothesized that anchorage with miniscrews is more cost-effective than anchorage with molar blocks. Trial design A single-centre, two-arm parallel-group randomized controlled trial. Methods Adolescents (age 11-19 years) in need of treatment with fixed appliance, premolar extractions, and en masse retraction were recruited from one Public Dental Health specialist centre. The intervention arm received anchorage reinforcement with buccal miniscrews during space closure. The active comparator received anchorage reinforcement with molar blocks during levelling/alignment and space closure. The primary outcome measure was societal costs defined as the sum of direct and indirect costs. Randomization was conducted as simple randomization stratified on gender. The patients, caregivers, and outcome assessors were not blinded. Results Eighty patients were randomized into two groups. The trial is completed. All patients were included in the intention-to-treat analysis. The median societal costs for the miniscrew group were € 4681 and for the molar block group were € 3609. The median of the difference was € 825 (95% confidence interval (CI) 431-1267). This difference was mainly caused by significantly higher direct costs consisting of material and chair time costs. Differences in chair time costs were related to longer treatment duration. No serious harms were detected, one screw fractured during insertion and three screws were lost during treatment. Generalizability and limitations The monetary variables are calculated based on a number of local factors and assumptions and cannot necessarily be transferred to other countries. Variables such as chair time, number of appointments, and treatment duration are generalizable. Owing to the study protocol, the benefit of miniscrews as a stable anchorage has not been fully utilized. Conclusions When only moderate anchorage reinforcement is needed, miniscrews are less cost-effective than molar blocks. The initial hypothesis was rejected. Miniscrews provide better anchorage reinforcement at a higher price. They should be used in cases where anchorage loss cannot be accepted.

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“…Superimposition was performed on digital 3dimensional models with a computer program (Final Surface; GFaI, Berlin, Germany) and according to the raw, fine matching, and deformation superimposition technique. 17 This technique calculates individual reference points for every subject. Reference points were detected with an algorithm-based deformation analysis that identified unchanged areas in the palate.…”

Section: Discussionmentioning

confidence: 99%

“…Because raw, fine matching, and deformation superimposition of digital 3-dimensional models was used, the movement of the maxillary molars could be mapped in a unique way. 17 Therefore, treatment effects are described in terms of translational movement, rotation, tipping, and torque. The analysis of tooth movement showed comprehensive information about the biomechanics of the 2 concepts used in this trial.…”

Section: Main Findingsmentioning

confidence: 99%

Anchorage reinforcement with miniscrews and molar blocks in adolescents: A randomized controlled trial

Ganzer

Feldmann

Bondemark

2018

American Journal of Orthodontics and Dentofacial Orthopedics

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A novel method for superimposition and measurements on maxillary digital 3D models—studies on validity and reliability

Abstract: The tested method is valid and reliable with excellent accuracy and precision even when changes through growth or orthodontic treatment occur.

Cited by 45 publications

References 21 publications

Virtual setup in orthodontics: planning and evaluation

Virtual setup in orthodontics: planning and evaluation

A cost-effectiveness analysis of anchorage reinforcement with miniscrews and molar blocks in adolescents: a randomized controlled trial

Anchorage reinforcement with miniscrews and molar blocks in adolescents: A randomized controlled trial

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