The forces generated with each appliance suggested more activation of the quad helix appliance was needed to produce a force and resultant effect comparable to that of the Crozat appliance.
The quad helix appliance is another treatment modality that is widely used in early expansion therapy.
The purpose of this investigation is to analyze the biomechanical and physical effects of the Crozat appliance when activated for transverse palatal expansion, and to compare these effects with the quad helix appliance.
The Crozat appliance was adjusted for 2 mm of anterior and posterior expansion, while the quad helix appliance was adjusted in subsequent increments to provide 2, 4, 6 and 8 mm of anterior and posterior expansion.
The occlusal views of additional activations of the Quad Helix appliance to 4, 6, and 8 mm are shown in Figures 6A through 6C.
The quad helix appliance initially revealed concentrated stress patterns in the posterior palatal region, and as the activation was increased to 6 and 8mm, the anterior palatal stress patterns gradually became more concentrated.
The data produced for the quad helix appliance is represented as a linear function.
The objective of this study was to analyze the biomechanical and physical effects of the Crozat appliance when activated for transverse palatal expansion, and to compare these effects with the biomechanical and physical characteristics of the Quad Helix appliance.
Literature has shown that the quad helix appliance primarily affects the alveolar bone surrounding the posterior teeth, especially around the banded teeth, with increasing stress patterns observed in this area with incremental activation of the appliance.
14) These findings demonstrate the increase in flexibility and range of force of the quad helix appliance due to the addition of the helical loops as stated by Chaconas and Caputo.
It was shown that a standard Crozat appliance can effectively generate force levels for transpalatal expansion similar to or greater than that seen with the quad helix appliance.
The Crozat appliance demonstrated higher forces with a short range of action, while the quad helix appliance demonstrated lighter forces over a long range of action.