Superimposition of maxillary digital models using the palatal rugae: Does ageing affect the reliability?

Abstract

Objectives: The aim of this study was to evaluate the reliability of 3-dimensional maxillary dental changes using two methods of digital model superimposition. Setting and Sample Population: The Department of Orthodontics of Bauru Dental School, University of São Paulo and University of Michigan Craniofacial Growth Center. Fifteen subjects with normal occlusion. Material & Methods: The sample was composed of digital study models of 15 normal occlusion subjects taken at 13 (T1), 18 (T2) and 60 years of age (T3). Using the software SlicerCMF 3.1, superimposition (registration) was conducted using 9 landmarks placed on the incisive papilla, second and third palatal rugae and 10 mm distal to the third palatal rugae. Two registration methods were compared: landmarks (LA) and regions of interest (ROI). Three-dimensional changes of landmarks on the buccal cusp tip of posterior teeth bilaterally and the incisal edge of the right central incisor were measured by three examiners. Intraclass correlation coefficients and Bland-Altman method evaluated intra- and inter-examiner agreements. Results: Good or excellent intra-examiner agreement was found for T1–T2 and T2–T3 measurements using both registration methods. Inter-examiner agreements were good to excellent for T1–T2 measurements and poor to fair for most T2–T3 measurements. Mean T1–T2 differences were less than 0.5 mm for most measurements. Conclusion: Maxillary digital dental models of patients with normal occlusion superimposed on palatal rugae showed an adequate reliability for a 5-year interval comparison using landmarks or regions of interest. Lower than acceptable reproducibility using both superimposition methods was found for a 40-year interval comparison.

Comparison of reliability, validity, and accuracy of linear measurements made on pre- and posttreatment digital study models with conventional plaster study models

“…This study showed good reproducibility of the measurement in both plaster and digital models similar to the studies by Okunami et al .,[8] Zilberman et al .,[13] Stevens et al .,[20] Quimby et al .,[21] and Bell et al . [22] The mesiodistal measurements on the digital pre- and posttreatment study models in this study were generally lesser than the manual measurements, as concluded by Stevens et al .,[20] Mullen et al .,[23] and Redlich et al .…”

“…[12] Garib et al . [13] showed a degree of reliability in the superimposition of the maxillary models with the digital models. Ko et al .…”

Mini Hyrax vs Hyrax expanders in the rapid palatal expansion in adolescents with posterior crossbite: a randomized controlled clinical trial

“…Several studies have used the palatal rugaes as reference structures in model superimpositions for assessing changes in tooth position resulting from growth and aging as well as orthodontic treatment [18,[30][31][32][33][34]. The medial point of the third rugae and the medial of the second rugae, in this order, have been determined as the most stable points [30,31,33,35].…”

“…No point was marked on the first rugae because changes in the position of the incisors during RPE, such as incisor extrusion and palatal inclination [ 27 ] cause changes in this rugae [ 35 , 38 ]. The two most distal points located on the median palatal raphe were included to increase the control of the “pitch” [ 18 , 34 ]. The ROI size of 15 was defined for all points, determining the area of superimposition in the middle of the palate to avoid lateral displacement (“roll” control) of the pre- and posttreatment models by the “best-fit.” This method has been adopted because the lateral inclination of the palatal vault changes with expansion [ 30 , 39 ].…”

Three-dimensional evaluation of conventional anterior open bite treatment with bonded spurs associated with build-ups versus conventional bonded spurs: a randomized clinical trial with 24-month follow-up

“…ROI with 15 to 20 mm radius were created on both models. 30 The software automatically computed and registered the models. Then, the "T2T1_reg_palatal" registered model with its registration matrix was created.…”