Predicting first molar width using virtual models of dental arches

Abstract

In dentistry, large regions of dentition often are restored with minimal information about the original anatomy. The ability to predict missing anatomy from existing anatomy would aid such restorations. This study investigated the relationship between first molar mesial-distal width and arch shape using newly defined reference points and three-dimensional (3D) digital methods. Full-mouth dental stone casts from 167 dental students were scanned and rendered as 3D virtual models. Maxillary and mandibular arch lengths and widths and first molar mesial-distal widths were measured on the virtual models using new definitions incorporating virtual planes. A linear mixed model of the first molar width regressed on the other measurements was done. Intraobserver reproducibility was evaluated by means of intraclass correlation (ICC) and standard deviation of measurement error (SDME). All measured distances were averaged as a combined group and as gender groups. The correlation coefficients between the maxillary and mandibular first molar widths were over 0.70 (P < 0.01). Intraobserver error was small. ICCs were over 0.92 and SDMEs were from 0.11 to 0.21 mm. Arch dimensions and first molar widths were defined and measured. Regression equations were calculated for predicting first molar width. The prediction of first molar width using arch dimension is essential for virtual designing of missing first molars. This approach also provides reliable reference point definitions for the virtual dental model which was impossible with traditional measurement methods. Therefore, this study would be helpful for understanding the 3D anatomy of dental arch and fabrication of automatic prosthodontic restorations.

Comparative Assessment of Dental Arch Relationships Using Goslon Yardstick in Patients with Unilateral Complete Cleft Lip and Palate Using Dental Casts, Two-Dimensional Photos, and Three-Dimensional Images

“…Since photographs taken from different centers are not standardized, some authors use plaster models for dental arch relationship assessment (Hathaway et al, 2011). Because of these reasons, interest in 3D images has increased (Lee et al, 2008; Bootvong et al, 2010). The use of 3D images has been suggested as an alternative for model storage and is now widely available and relatively inexpensive.…”

Dental archforms in dentoalveolar Class I, II and III

“…13,17 The traditional odontometric tools were the sliding calipers, but recently three-dimensional (3D) scanners and specialized software have been developed to provide accurate digital models of dental structures that allow us to do sophisticated and more precise measurements. 24 Therefore, the aim of this study was to investigate arch dimensions defined on virtual 3D dental arches in dentoalveolar Class I, II, and III, and the differences between male and female subjects. The hypothesis was that no differences exist between dentoalveolar classes or in gender dimorphism.…”

The development of quantitative methods using virtual models for the measurement of tooth wear

“…Reproducibility of the parameters is a very important factor for comparing data between different studies. Therefore, the ICC and SDME were calculated, as in other three‐dimensional studies (Zilberman et al,2003; Lee et al,2008) The ICCs and SDMEs indicate that the reproducibility is good. Moreover, the angle and height parameters show better concordance than the distance parameters.…”

“…Also, the distance between each point was measured to confirm whether any valuable parameters exist. The highest and deepest points within the region of interest were automatically selected using software from other studies (Park et al,2007; Cheon et al,2008; Lee et al,2008).…”

“…The accuracy and reproducibility of three‐dimensional virtual models is established (Mehl et al,1997; Peters et al,1999; Kim et al,2007; Lee et al,2008). Complex and sophisticated measurements and mathematical calculations, which are impossible with conventional models, are made based on these virtual models (Sohmura et al,2000; DeLong et al,2003; Hayashi et al,2003; Kim et al,2007; Lee et al,2008). For example, it is impractical to use traditional calipers for generating virtual lines or planes, and the accurate and reproducible distance or angle measurements between virtual points.…”