Comparison of orthodontic measurements on dental plaster casts and 3D scans

Abstract

Inexperienced examiners, in particular, take measurements of mesiodistal tooth dimensions faster using a software-based method than when using a dental vernier caliper. Similar values were obtained with both methods.

Are Dental Measurements Taken on Plaster Casts Comparable to Those Taken From CBCT Images and Laser Scanned Surfaces?

“…Additionally, the current results well confirm that measurements involving the premolars are more variable than the other ones [4]. In general, the overestimation of calliper measurements vs. digital casts data is in line with the literature reports [18], while the comparison with CBCT data is more scattered. For instance, on dry mandibles, most of CBCT measurements were significantly smaller than those obtained by using the calliper [6].…”

“…Literature is not in agreement about the technique with the best reproducibility: both digital models [4,5,7], and plaster models [16] had the best scores in different studies. Overall, only three mesiodistal crown diameters had differences larger than 0.5 mm, which is considered the threshold for clinical acceptability [7,18]. This corresponds to 8% of the analysed dental distances (3 out of 12 distances x 3 techniques values), a value larger than that reported by Tarazona-Álvarez et al [6] who found only 5% of significant differences when comparing 20 linear distances obtained directly on dried mandibles and on their CBCT scans.…”

“…2). Only three differences were larger than 0.5 mm, which represents the threshold for clinical acceptability [7,18]: calliper-CBCT for teeth 41 and 24, and digital-CBCT for tooth 24 (all mesiodistal crown diameter). Calliper measurements slightly overestimated digital cast values, while the other differences were more scattered.…”

“…The results were discussed until a consensus about landmark location was obtained. Intra-and inter-operator reliability was assessed by Bland-Altman analysis, and for each comparison both the reproducibility coefficient and the bias (difference between measurements divided by the mean value) were calculated [7,18].…”

“…In this last field, several studies have successfully compared the accuracy of craniofacial measurements taken using landmarks identified on CBCT scans with those taken directly on skulls with conventional digital callipers [16,17]. Safety, accuracy and reliability of measurements taken with new instruments must be evaluated and compared with those obtained with traditional methods also for dental landmarks: data obtained from both the digital and traditional plaster casts models must match in order to allow using the new technologies in clinical practice [2,8,18]. In general, recent investigations found that measurements taken on digital models do not differ clinically from those obtained on CBCT scans and physical models [4,5].…”