Korean J Orthod.  2015 Sep;45(5):226-235. 10.4041/kjod.2015.45.5.226.

Short-term and long-term treatment outcomes with Class III activator

• Ryu HK
• Chong HJ
• An KY
• Kang KH

• KMID: 2068517
• DOI: http://doi.org/10.4041/kjod.2015.45.5.226

Abstract

OBJECTIVE
The purpose of this retrospective study was to investigate short-term and long-term skeletodental outcomes of Class III activator treatment.
METHODS
A Class III activator treatment group (AG) comprised of 22 patients (9 boys, 13 girls) was compared with a Class III control group (CG) comprised of 17 patients (6 boys, 11 girls). The total treatment period was divided into three stages; the initial stage (T1), the post-activator treatment or post-mandibular growth peak stage (T2), and the long-term follow-up stage (T3). Cephalometric changes were evaluated statistically via the Mann-Whitney U-test and the Friedman test.
RESULTS
The AG exhibited significant increases in the SNA angle, ANB angle, Wits appraisal, A point-N perpendicular, Convexity of A point, and proclination of the maxillary incisors, from T1 to T2. In the long-term follow-up (T1-T3), the AG exhibited significantly greater increases in the ANB angle, Wits appraisal, and Convexity of A point than the CG.
CONCLUSIONS
Favorable skeletal outcomes induced during the Class III activator treatment period were generally maintained until the long-term follow-up period of the post-mandibular growth peak stage.

Keyword

Class III activator; Skeletodental changes

MeSH Terms

Follow-Up Studies
Humans
Incisor
Retrospective Studies

Figure

• 

  Figure 1 Landmarks and reference planes. S, Sella; N, Nasion; Po, Porion; Or, Orbitale; Co, Condylion; Ar, Articulare; ANS, anterior nasal spine; PNS, posterior nasal spine; A, Point A; B, Point B; U1E, incisal edge of maxillary central incisor (U1); U1A, root apex of U1; L1E, incisal edge of mandibular incisor (L1); L1A, root apex of L1; Pog, Pogonion; Gn, Gnathion; Me, Menton; Go, Gonion; Sella-Nasion plane (SN plane), line from S to N; Frankfort horizontal plane (FH plane), line from Po to Or; Palatal plane, line from PNS to ANS; Functional occlusal plane, line drawn along the maximum intercuspation of the posterior teeth; N-perpendicular plane (N-perp plane), perpendicular line to FH plane passing through Nasion; Facial plane, line from N to Pog; Mandibular plane, line from Go to Me.

• 

  Figure 2 Cephalometric measurements. 1, SNA; 2, SNB; 3, ANB; 4, Palatal plane angle; 5, Mn. plane angle; 6, Gonial angle; 7, lower gonial angle; 8, AB to Mn. plane angle; 9, Y-axis angle; 10, ODI; 11, APDI; 12, U1 to SN; 13, U1 to FH; 14, IMPA; 15, Wits appraisal; 16, Mx. length; 17, Mn. length; 18, A-N perpend; 19, Pog-N perpend; 20, Convexity of A.

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