Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2013 Nov;83(6):948-55.
doi: 10.2319/011913-48.1. Epub 2013 Jun 11.

Lower incisor dentoalveolar compensation and symphysis dimensions among Class I and III malocclusion patients with different facial vertical skeletal patterns

Núria Molina-Berlanga  1 , Jaume Llopis-Perez, Carlos Flores-Mir, Andreu Puigdollers
Affiliations
Comparative Study

Lower incisor dentoalveolar compensation and symphysis dimensions among Class I and III malocclusion patients with different facial vertical skeletal patterns

Núria Molina-Berlanga et al. Angle Orthod. 2013 Nov.

Abstract

Objective: To compare lower incisor dentoalveolar compensation and mandible symphysis morphology among Class I and Class III malocclusion patients with different facial vertical skeletal patterns.

Materials and methods: Lower incisor extrusion and inclination, as well as buccal (LA) and lingual (LP) cortex depth, and mandibular symphysis height (LH) were measured in 107 lateral cephalometric x-rays of adult patients without prior orthodontic treatment. In addition, malocclusion type (Class I or III) and facial vertical skeletal pattern were considered. Through a principal component analysis (PCA) related variables were reduced. Simple regression equation and multivariate analyses of variance were also used.

Results: Incisor mandibular plane angle (P < .001) and extrusion (P = .03) values showed significant differences between the sagittal malocclusion groups. Variations in the mandibular plane have a negative correlation with LA (Class I P = .03 and Class III P = .01) and a positive correlation with LH (Class I P = .01 and Class III P = .02) in both groups. Within the Class III group, there was a negative correlation between the mandibular plane and LP (P = .02). PCA showed that the tendency toward a long face causes the symphysis to elongate and narrow. In Class III, alveolar narrowing is also found in normal faces.

Conclusions: Vertical facial pattern is a significant factor in mandibular symphysis alveolar morphology and lower incisor positioning, both for Class I and Class III patients. Short-faced Class III patients have a widened alveolar bone. However, for long-faced and normal-faced Class III, natural compensation elongates the symphysis and influences lower incisor position.

PubMed Disclaimer

Figures

Figure 1. The position of the lower incisor: IMPA and extrusion.
Figure 1.
The position of the lower incisor: IMPA and extrusion.
Figure 2. The dimensions of the symphysis: LP, LA, and LH.
Figure 2.
The dimensions of the symphysis: LP, LA, and LH.
Figure 3. Extrusion value in three types of Class III overjets. (a) Positive. (b) Negative. (c) Edge-to-edge.
Figure 3.
Extrusion value in three types of Class III overjets. (a) Positive. (b) Negative. (c) Edge-to-edge.
Figure 4. IMPA variation in Class I and Class III.
Figure 4.
IMPA variation in Class I and Class III.
Figure 5. Extrusion variation in Class I and Class III.
Figure 5.
Extrusion variation in Class I and Class III.
Figure 6. Average value for principal components 1 (CP1) and 2 (CP2) in Classes I and III.
Figure 6.
Average value for principal components 1 (CP1) and 2 (CP2) in Classes I and III.
Figure 7. Principal components 1 (CP1), 2 (CP2), and 3 (CP3) in Classes I and III.
Figure 7.
Principal components 1 (CP1), 2 (CP2), and 3 (CP3) in Classes I and III.
See this image and copyright information in PMC

References

    1. Goldsman S. The variations in skeletal and denture patterns in excellent adult facial types. Angle Orthod. 1959;29:63–92.
    1. Bibby RE. Incisor relationships in different skeletofacial patterns. Angle Orthod. 1980;50:41–44. - PubMed
    1. Jacobson A, Evans WG, Preston CG, Sadowsky PL. Mandibular prognathism. Am J Orthod. 1974;66:140–171. - PubMed
    1. Nielsen IL. Vertical malocclusions: etiology, development, diagnosis and some aspects of treatment. Angle Orthod. 1991;61:247–260. - PubMed
    1. Burns NR, Musich DR, Martin C, Razmus T, Gunel E, Ngan P. Class III camouflage treatment: what are the limits. Am J Orthod Dentofacial Orthop. 2010;137:9. - PubMed

Publication types

LinkOut - more resources