Cephalometric appraisal of Class II treatment effects after functional and fixed appliances: a retrospective study

Abstract

SummaryObjective: To assess the dental, skeletal, and profile changes after functional appliances and subsequent fixed appliances treatment in order to quantify their effect and evaluate the influence of initial incisal inclination and growth pattern. Materials and methods: A retrospective cephalometric analysis was performed in 125 patients (77 females and 48 males). Three lateral cephalograms per patient were available: before treatment (T0, mean age 11.9 years), after functional treatment (T1, mean age 12.9 years), and after fixed appliances (T2, mean age 14.8 years). Results: At T1, a decrease of SNA (0.38° ± 0.77, P < 0.05), an increase of SNB (1.46° ± 0.66, P < 0.05), and a less convex profile (increase N′-Sn′-Pog′ of 2.93° ± 0.87, P < 0.05) were observed as compared to T0. The position of the upper incisors normalizes: initially retroclined upper incisors showed proclination and proclined incisors retroclination. At T1, proclination of the lower incisors was also noticed, being smaller the higher the initial I^NB. At T2, no significant changes in upper and lower incisor position were noticed compared to T1, as well as a decrease of the SNA (1.17° ± 0.75, P < 0.001) and SNB angles (0.41° ± 0.64, P < 0.05) and a stable profile convexity. Conclusion: The improvement of the Class II relationship at T1 was mostly due to dentoalveolar changes: correction of the upper incisor position and proclination of the lower incisors. Skeletal changes were also noticed: constriction of maxillary growth combined with a growth stimulation of the mandible. At T2, no further proclination of the lower incisors was noticed.

Evaluation of growth changes induced by functional appliances in children with Class II malocclusion: Superimposition of lateral cephalograms on stable structures

“…The power calculation was performed using variables such as condylar growth and sagittal jaw changes from previous studies. 1,2 For sufficient power (80%) to identify relevant differences at a 5% level of significance, and considering an allocation ratio of 1:1.5, at least 16 and 24 children were required in the untreated control and each treatment group, respectively. The Z-activator consists of an activator combined with a high-pull headgear (force vector between the center of resistance of the nasomaxillary complex and maxillary dentition).…”

“…The improvement in the sagittal jaw relationship was achieved by restricted maxillary growth and additional condylar growth, although the significant condylar growth was not associated with significant advancement of the chin. It is generally agreed that functional appliances can accelerate mandibular growth on a short-term basis, although there is controversy regarding sagittal advancement of the chin position [1][2][3][4][5] due to the association between the sagittal and vertical dimensions. [7][8][9] Teuscher 10 previously pointed out that posterior rotation of the maxilla is the major component that forces the mandible to rotate posteriorly, and he proposed the Z-activator, a combined headgear-activator appliance, for prevention of this unfavorable effect.…”

“…Functional appliances have been widely used for growth adaptation/modification treatment in growing children with Class II malocclusion, and their effects have been extensively discussed. [1][2][3][4][5] Some authors documented that functional appliances are effective in improving dentoalveolar and skeletal relationships, while others presented that skeletal effects are minimal relative to those in untreated controls on a long-term basis. [1][2][3][4][5] In most studies, growth changes induced by functional appliances were conventionally measured on lateral cephalograms, with the use of points and lines for identifying sagittal jaw changes measured on the chin point and vertical changes measured on the mandibular line in relation to the nasion-sella line (NSL).…”

“…[1][2][3][4][5] Some authors documented that functional appliances are effective in improving dentoalveolar and skeletal relationships, while others presented that skeletal effects are minimal relative to those in untreated controls on a long-term basis. [1][2][3][4][5] In most studies, growth changes induced by functional appliances were conventionally measured on lateral cephalograms, with the use of points and lines for identifying sagittal jaw changes measured on the chin point and vertical changes measured on the mandibular line in relation to the nasion-sella line (NSL). [2][3][4][5] However, it was found that these methods underestimate the vertical displacement and rotations of the jaws, and that the dynamics of jaw rotations are often masked because of instability of the points and lines during growth.…”

“…[1][2][3][4][5] In most studies, growth changes induced by functional appliances were conventionally measured on lateral cephalograms, with the use of points and lines for identifying sagittal jaw changes measured on the chin point and vertical changes measured on the mandibular line in relation to the nasion-sella line (NSL). [2][3][4][5] However, it was found that these methods underestimate the vertical displacement and rotations of the jaws, and that the dynamics of jaw rotations are often masked because of instability of the points and lines during growth. [6][7][8][9] Moreover, in many studies, initial correction using functional appliance treatment involved not only forward positioning of the mandible but also vertical opening of the bite and an increase in the lower anterior facial height.…”