Friction of conventional and silica-insert ceramic brackets in various bracket-wire combinations

Jung Yul Cha, Kyung Suk Kim, Chung Ju Hwang

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Objective: To compare the level of friction resistance (FR) of conventional and silica-insert ceramic brackets using various bracket-wire combinations and angulations. Materials and Methods: Four types of ceramic brackets were examined: (1) polycrystalline alumina bracket (PCA-C), (2) polycrystalline alumina bracket with a stainless steel (SS) slot (PCAM), (3) polycrystalline alumina bracket with a silica layer (PCA-S), and (4) monocrystalline sapphire bracket (MCS). A conventional SS bracket was used as the control. The static and kinetic FR in four bracket-wire angulations (0°, 5°, 10°, and 15°) was examined using SS and β-titanium (β-Ti) orthodontic wires, 0.019 x 0.025 inches in size, under elastic ligature in the dry state. Results: The FR generated by the PCA-S bracket was significantly lower than that generated with the other ceramic brackets, and was similar to that of the SS bracket. The PCA-S bracket showed the lowest FR with both the SS and the β-Ti wires at zero bracket angulation. The FR to sliding increased rapidly and nonlinearly when the bracket wire angulation was >5°. The PCS-S bracket showed the lowest FR from 5° to 15° of angulation. The MCS bracket demonstrated the highest increase in FR from 0° to 15° of angulation, showing the highest FR at 15° of angulation. Conclusion: PCA-S showed minimal FR among the ceramic brackets, and was comparable to the conventional SS bracket. The silica layer and rounded edges of the ceramic slot lowered FR considerably.

Original languageEnglish
Pages (from-to)100-107
Number of pages8
JournalAngle Orthodontist
Issue number1
Publication statusPublished - 2007 Jan 1


All Science Journal Classification (ASJC) codes

  • Orthodontics

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