Comparing Incisor Inclination in Class III Surgery and Camouflage Patients

Dentoalveolar compensations are common in Class III malocclusions and help maintain function and mask underlying skeletal discrepancy.  Decompensating dental arches and aligning teeth to ideal axial inclination are pre-surgical goals.  Camouflage treatment, on the other hand, builds on natural dental compensations for skeletal discrepancy.  Objectives:  To determine if there were differences in incisor inclination between patients with Class III skeletal malocclusions treated by surgery or camouflage.  Methods:  Thirty surgical-orthodontic Class III patients and thirty-nine camouflage Class III patients were selected with the following criteria:  overjet of 0mm or less, Angle Class III molar relationship, and ANB less than 0.1.  Records included pre-treatment (T1) and final (T3) lateral cephalometric radiographs for both groups, in addition to pre-surgery (T2) radiographs for the surgical group.  Upper incisor (U1) and lower incisor (L1) measurements included U1-SN, U1-NA (mm and degrees), L1-Go-Gn, and L1-NB (mm and degrees).  Intra-rater reliability was established, and mean and dynamic efficacy evaluations referenced to ideal were calculated.  Significant effects and differences between means were identified by repeated measures ANOVA and subsequent Bonferroni-corrected t-tests. 

Results: 

	Mean Angle Values			Time Periods
Angle Measure	T1	T2	T3	T1-2	T2-3	T1-3
CAMOUFLAGE
U1-SN	105.0		110.3			*
U1-NA	25.4		30.1			*
L1-Go-Gn	91.1**		86.2			*
L1-NB	22.6**		16.9			*
SURGERY
U1-SN	108.0	108.2	111.1
U1-NA	28.3	28.5	28.8
L1-Go-Gn	82.6**	88.2	85.9	*		*
L1-NB	17.0**	22.8	18.4	*	*

  *Statistically significant difference between time points p<0.05

**Statistically significant difference between treatment method for this time point p<0.05

Conclusions:  Change in incisor inclinations occur for both camouflage and surgical Class III treatment and were different from each other.  Even when purposefully decompensating the occlusion, incisor inclinations frequently do not reach the orthodontic ideal.