IADR Abstract Archives

The Effect of Hard Tissue Surgical Changes on Soft Tissue

Objectives: The purpose of this pilot study was to test reliability of a new method to evaluate orthognathic surgery outcomes and, secondarily, to understand the effect of hard tissue changes on soft tissue displacement.
Methods: The sample consisted of eight patients who underwent bimaxillary advancement and had CBCT at two time points (before surgery and 6-8 months follow-up). Voxel-based cranial base superimposition was used to register the scans. Three-dimensional surface models were created and a different technique of iterative closest point, which focused on areas rather than specific landmarks, was used to measure and correlate the changes. Imagine and ITK-Snap (both NIH funded) were used to perform the superimposition and create the surface models, respectively. VAM (Canfield Scientific, Fairfield, NJ) was used to perform the measurements. The average displacements of 15 areas (4 hard tissue and 11 soft tissue, figure 1) were measured twice after a one-month washout period. Intraclass correlation coefficient (ICC) was done to test the measurements’ reproducibility and Spearman rank correlation was used to correlate the hard and soft tissue changes. The correlation was divided between maxillary and mandibular areas. Significance was set at p<0.05.
Results: ICC was >.99 for all measurements. Tables 1 and 2 show the correlation between hard and soft tissue changes for the upper and lower jaw, respectively. Changes of the tip of the nose did not correlate with changes in any maxillary area, whereas soft tissue A point, A point and upper lips had correlation with several areas. The highest correlation for the maxilla was between the upper lip and the left/right supra cheilion (p<.01, r=.91 and p<.01, r=.93, respectively). In the mandible, very few areas were correlated and the majority of them involved soft tissue pogonion, pogonion and lower incisors with the strongest between pogonion and lower incisors (p<.01, r=.98).
Conclusions: The method showed high reproducibility for the measurements. The correlation found in this and future studies with greater sample sizes can help to predict the soft tissue outcomes of orthodontic-surgical therapies and aid professionals in developing goal-oriented treatment plans.

Division: IADR/AADR/CADR General Session
Meeting: 2017 IADR/AADR/CADR General Session (San Francisco, California)
Location: San Francisco, California
Year: 2017
Final Presentation ID: 3998
Abstract Category|Abstract Category(s): Oral & Maxillofacial Surgery Research

Authors

Koerich De Paula, Leonardo ( Virginia Commonwealth University , Richmond , Virginia , United States )

Ohira, Eduardo ( Private Practice , Pomerode , Brazil )

Brunetto, Daniel ( Federal University of Parana , Curitiba , Brazil )

Lindauer, Steven ( Virginia Commonwealth University , Richmond , Virginia , United States )

Financial Interest Disclosure: None

SESSION INFORMATION

Poster Session
Oral & Maxillofacial Surgery IV
Saturday, 03/25/2017 , 03:45PM - 05:00PM

TABLES

Table 1 - Spearman correlation between structures in the upper jaw.

	Nasal Tip	Soft A Point	A Point	Upper Lip	Upper Incisors	Left Cheilion	Right Cheilion	Left Supra Cheilion	Right Supra Cheilion
Nasal Tip	-	0.41	0.16	0.48	0.25	0.09	0.25	0.48	0.37
Soft A Point	-0.10	-	0.04	<0.01	0.03	0.04	0.25	0.01	0.03
A Point	0.40	0.66	-	<0.01	0.08	<0.01	0.08	0.01	0.01
Upper Lip	0.02	0.86	0.86	-	0.04	0.01	0.07	<0.01	<0.01
Upper Incisors	0.29	0.68	0.55	0.64	-	0.04	0.33	0.08	0.13
Left Cheilion	0.52	0.66	0.86	0.83	0.67	-	0.25	0.03	0.04
Right Cheilion	-0.29	0.29	0.55	0.57	-0.19	0.29	-	0.05	0.02
Left Supra Cheilion	-0.02	0.79	0.76	0.91	0.55	0.69	0.62	-	0.01
Right Supra Cheilion	-0.14	0.67	0.79	0.93	0.45	0.67	0.74	0.83	-

Correlations are below and p values above the dashes.
Table 2 – Spearman correlation between structures in the lower jaw.

	Left Sub Cheilion	Right Sub Cheilion	Lower Lip	Lower Incisors	Soft Pogonion	Pogonion
Left Sub Cheilion	-	0.21	0.37	0.19	0.02	0.16
Right Sub Cheilion	0.33	-	0.04	0.09	0.08	0.08
Lower Lip	0.14	0.67	-	0.10	0.12	0.09
Lower Incisors	0.36	0.52	0.50	-	0.02	<0.01
Soft Pogonion	0.74	0.55	0.48	0.71	-	0.04
Pogonion	0.40	0.55	0.52	0.98	0.67	-

Correlations are below and p values above the dashes.

IMAGES

Soft and hard tissue areas with color-coded distances in one patient. A – Nasal tip, B – Soft A Point, C – A Point, D – Upper Lip, E – Upper Incisors, F – Left/Right Cheilion, G – Left/Right Supra Cheilion, H – Left/Right Sub Cheilion, I – Lower Lip, J – Lower Incisors, K – Soft Pogonion, L – Pogonion. Black circles are the areas initially evaluated and were removed because they were not reliable.

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