Qualitative correlation between postoperatively increased vertical dimension and mandibular position in skeletal class III using partial-least-square path modeling

Na-Ri Kim,Yong-Il Kim,Jihyun Lee,Soo-Byung Park,Yong-Seok Choi,Youn-Kyung Choi,Sang Min Shin

doi:10.1186/s40902-017-0114-4

Abstract

BackgroundThis study constructed a partial-least-square path-modeling (PLS-PM) model and found the pathway by which the postsurgical vertical dimension (VD) affects the extent of the final mandibular setback on the B point at the posttreatment stage for the skeletal class III surgery-first approach (SFA).MethodsThis study re-analyzed the data from the retrospective study by Lee et al. on 40 patients with skeletal class III bimaxillary SFA. Variables were obtained from cone beam computed tomography (CBCT)-generated cephalograms. Authors investigated all variables at each time point to build a PLS-PM model to verify the effect of the VD on the final setback of the mandible.ResultsFrom PLS-PM, an increase in VD10 was found to decrease the absolute value of the final setback amount of the mandible, which reflects the postsurgical physiological responses to both surgery and orthodontic treatment, which, in turn, can be interpreted as an increase in postoperative mandibular changes.ConclusionsTo resolve the issue of collinear cephalometric data, the present study adopted PLS-PM to assess the orthodontic treatment. From PLS-PM, it was able to summarize the effect of increased postsurgery occlusal vertical dimension on the increased changeability of the B point position at the posttreatment stage.

Highlights

This study constructed a partial-least-square path-modeling (PLS-PM) model and found the pathway by which the postsurgical vertical dimension (VD) affects the extent of the final mandibular setback on the B point to S-perpendicular plane (S-perp) (Bs) point at the posttreatment stage for the skeletal class III surgery-first approach (SFA)
A point to S-perp (As) for the outer model, the manifest variables (MVs) of Bs10 and Mes10 were presumed to cause LV10, while those of As1 and Cpf1 were presumed to cause LV1, and those of Bs10; Mes10; As1; Cpf1 and VD10 to cause LVoverall, in the formative senseÀ[12]Á; the extent of final mandibular setback Bs20 was presumed to be caused by LVsetback in the reflective sense (Fig. 2)
We confirmed that the PLS-PM as derived in our study signified the effect of occlusal VD on the extent of final mandibular setback and that an increase in VD leads to a decrease in the absolute amount of the final setback and, more severe postsurgical skeletal changes (Fig. 2)

Summary

Introduction

This study constructed a partial-least-square path-modeling (PLS-PM) model and found the pathway by which the postsurgical vertical dimension (VD) affects the extent of the final mandibular setback on the B point at the posttreatment stage for the skeletal class III surgery-first approach (SFA). Many clinical studies in dental research have used multiple regression analysis to find correlations between the predictor and the response variables. One possible problem with this approach is the collinearity between or among predictors. In statistics, when there are more than two predictors that are highly correlated, it is called collinearity [1, 2]. PLS modeling is often used as an alternative to conventional statistical. Unlike conventional modeling methods, which rely on covariance decomposition, PLS is a variance-based method that does not carry the covariance assumptions. PLS is less sensitive to the problems arising from collinearity [6, 7]

Objectives

Methods

Results

Discussion

Conclusion