Korean J Orthod.  2016 Jul;46(4):212-219. 10.4041/kjod.2016.46.4.212.

Treatment effects of mandibular total arch distalization using a ramal plate

• Yu J
• Park JH
• Bayome M
• Kim S
• Kook YA
• Kim Y
• Kim CH

• KMID: 2392201
• DOI: http://doi.org/10.4041/kjod.2016.46.4.212

Abstract

OBJECTIVE
The purpose of this study was to evaluate treatment effects after distalization of the mandibular dentition using ramal plates through lateral cephalograms.
METHODS
Pre- and post-treatment lateral cephalograms and dental casts of 22 adult patients (11 males and 11 females; mean age, 23.9 ± 5.52 years) who received ramal plates for mandibular molar distalization were analyzed. The treatment effects and amount of distalization of the mandibular molars were calculated and tested for statistical significance. The significance level was set at p < 0.001.
RESULTS
The mandibular first molar distalization at the crown and root were 2.10 mm (p < 0.001) and 0.81 mm (p = 0.011), respectively. In the evaluation of skeletal variables, there was a significant increase in the Wits appraisal (p < 0.001). In the evaluation of the soft tissue, there was no significant effect on upper lip position, but the lower lips showed a significant retraction of 2.2 mm (p < 0.001).
CONCLUSIONS
The mandibular molars showed a significant amount of distalization accompanied by limited extrusion and mesiobuccal rotation of the crowns. A ramal plate may be a viable device for mandibular total arch distalization in Class III patients who are reluctant to undergo orthognathic surgery.

Keyword

Distalizing; Miniplate; Class III treatment; Total arch distalization; Cephalometrics

MeSH Terms

Adult
Crowns
Dentition
Female
Humans
Lip
Male
Molar
Orthognathic Surgery

Figure

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  Figure 1 The placement site of the ramal plate showing the retromolar fossa. A, The placement site of the ramal plate; B, the ramal plate after adjustment to fit into the retromolar fossa; C, the ramal plate emerging through the attached gingiva; and D, the ramal plate connected to an archwire with a power chain elastic.

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  Figure 2 Cephalometric radiographs are shown. A, Pretreatment; B, after leveling and alignment; and C, post-treatment.

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  Figure 3 Cephalometric reference lines and variables. A, Frankfort horizontal (FH) plane; B, perpendicular to the FH at the pterygoid; C, mandibular plane (MP); D, perpendicular to MP at menton. 1, Molar crown to B; 2, molar root to B; 3, molar crown to A; 4, molar root to A; 5, molar long axis–A angle; 6, incisor crown to B; 7, incisor root to B; 8, incisor crown to A; 9, incisor root to A; 10, incisor long axis–A angle; 11, molar crown to D; 12, molar root to D; 13, molar crown to C; 14, molar root to C; 15, molar long axis–C angle; 16, incisor crown to D; 17, incisor root to D; 18, incisor crown to C; 19, incisor root to C; and 20, incisor long axis–C angle.

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  Figure 4 Cephalometric skeletal and soft-tissue measurements. 1, A point-nasion-B point (ANB); 2, sella-nasion-B point (SNB); 3, Wits; 4, perpendicular to Pog–N; 5, FH to manidibular plane angle (FMA); 6, facial height ratio (posterior facial height 6a/anterior facial height 6b); 7, nasolabial angle; 8, true vertical line-upper lip; 9, true vertical line-lower lip; 10, true vertical line-soft tissue pogonion; 11, stomion inferior-soft tissue menton/subnasale-stomion superior.

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