Coefficients of friction for arch wires in stainless steel and polycrystalline alumina bracket slots. I. The dry state

Kusy, Robert P.; Whitley, Julia

doi:10.1016/s0889-5406(05)81487-8

Cited by 119 publications

(75 citation statements)

References 8 publications

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“…Earlier studies revealed that the ceramic bracket generated a higher FR than the metal bracket on account of the chemical adhesion and surface roughness. [2][3][4][5][6] Even though metal-slot-insert ceramic brackets have been successful in reducing FR compared with monocrystalline ceramic brackets, they still exhibited a higher FR than the metal brackets. 11 Interestingly, the polycrystalline ceramic bracket with the silica insert (PCA-V) produced significantly lower FR than the conventional metal brackets.…”

Section: Discussionmentioning

confidence: 99%

“…However, their high coefficient of friction has limited their use. [1][2][3][4][5][6] It has been reported that the friction resistance (FR) of ceramic brackets is increased by their rough surface conditions. In addition, the chemical characteristics of alumina on a ceramic surface can cause a metal wire to adhere to the alumina surface.…”

Section: Introductionmentioning

confidence: 99%

“…15,21 For these reasons, there have been many studies examining the FR of ceramic brackets under different experimental conditions. 1,[4][5][6][7][8][9][10][11][12] The FR of ceramic brackets is generally measured by moving a wire parallel to the bracket slot. [2][3][4][5][6] However, in practice, teeth tend to move by repeatedly tipping and uprighting rather than by moving parallel to the bracket slot.…”

Section: Introductionmentioning

confidence: 99%

“…1,[4][5][6][7][8][9][10][11][12] The FR of ceramic brackets is generally measured by moving a wire parallel to the bracket slot. [2][3][4][5][6] However, in practice, teeth tend to move by repeatedly tipping and uprighting rather than by moving parallel to the bracket slot. 22,23 With regard to the tipping movement of a tooth, Kusy and Whitley 19,20 measured the critical angulation () which is the angle at which the space between the bracket and wire is lost and binding between the bracket and archwire begins to occur.…”

Section: Introductionmentioning

confidence: 99%

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Friction of Conventional and Silica-Insert Ceramic Brackets in Various Bracket-Wire Combinations

Yul

Kim

Hwang

2007

The Angle Orthodontist

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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 (PCA-M), (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 (0Њ, 5Њ, 10Њ, and 15Њ) was examined using SS and ␤-titanium (␤-Ti) orthodontic wires, 0.019 ϫ 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 ␤-Ti wires at zero bracket angulation. The FR to sliding increased rapidly and nonlinearly when the bracket wire angulation was Ͼ5Њ. The PCS-S bracket showed the lowest FR from 5Њ to 15Њ of angulation. The MCS bracket demonstrated the highest increase in FR from 0Њ to 15Њ of angulation, showing the highest FR at 15Њ 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.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Friction of Conventional and Silica-Insert Ceramic Brackets in Various Bracket-Wire Combinations

Yul

Kim

Hwang

2007

The Angle Orthodontist

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“…Ceramic brackets were developed to improve esthetics during orthodontic treatment, with a continuous effort to overcome several problems of these types of brackets: brittleness leading to bracket or tie-wing failure, iatrogenic enamel damage during debonding, enamel wear of opposing teeth, and high frictional resistance to sliding mechanics. [2][3][4][5][6] Beside esthetics, a second desirable condition in fixed appliance therapy with preadjusted brackets consists in the reduction of ''frictional'' forces between the bracket and the guiding archwire during both the initial treatment phases of leveling and aligning and the sliding mechanics for space closure. Friction is the resistance to motion that exists when a solid is moved tangentially with respect to the surface of another contacting solid.…”

Section: Introductionmentioning

confidence: 99%

Forces in the Presence of Ceramic Versus Stainless Steel Brackets with Unconventional vs Conventional Ligatures

Baccetti

Franchi

Camporesi

2008

The Angle Orthodontist

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Objective: To compare the forces resulting from four types of bracket/ligature combinations: ceramic brackets and stainless steel brackets combined with unconventional elastomeric ligatures (UEL) and conventional elastomeric ligatures (CEL) during the leveling and aligning phases of orthodontic therapy. Materials and Methods:The testing model consisted of five 0.022-inch preadjusted brackets (second premolar, first premolar, canine, lateral incisor, and central incisor) for each of the two bracket types. The canine bracket was welded to a sliding bar that allowed for different amounts of offset in the gingival direction. The forces generated by a 0.014-inch superelastic nickel titanium wire in the presence of either the UEL or CEL bracket/ligature systems at different amounts of upward canine misalignment (1.5 mm, 3 mm, 4.5 mm, and 6 mm) were recorded. Results: Significant differences were found between UEL and CEL systems for all tested variables (P Ͻ .01) with the exception of the canine misalignment of 1.5 mm. The average amount of recorded force in the presence of CEL was negligible with 3.0 mm or greater of canine misalignment. On the contrary, during alignment, a force available for tooth movement was recorded in the presence of both ceramic and stainless steel brackets when associated with UEL. Conclusions: The type of ligature used influenced the actual amount of force released by the orthodontic system significantly more than the type of bracket used (stainless steel vs ceramic).

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Resistance to sliding of orthodontic appliances in the dry and wet states: Influence of archwire alloy, interbracket distance, and bracket engagement

Kusy

Whitley

2000

J. Biomed. Mater. Res.

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Having established dimensional and mechanical characteristics, the resistances to sliding (RS) were measured in vitro for various archwires against stainless steel brackets. Using stainless steel ligatures, a constant normal force (300g) was maintained while second-order angulation (straight theta) was varied from -12 degrees to +12 degrees. Using miniature bearings to simulate contiguous teeth, five experiments each were run in the dry or wet states with human saliva at 34 degrees C as a function of four archwire alloys, five interbracket distances, and two bracket engagements. Outcomes were objectively analyzed to establish when theta=0, and the relative contact angles ( theta(r)) were replotted. Critical contact angles (theta(c)) that were determined via experimentation were in good agreement with theory. Slopes and y-intercepts were tabulated from linear regression equations of RS against theta plots in both the passive (theta < or = theta (c)) and active ( theta > or = theta(c)) configurations, for which theta = theta(c) identified the boundary between classical friction and binding phenomena. Stiffer archwires and shorter interbracket distances exacerbated binding, whereas, once corrected for differing bracket engagement, RS was independent of slot dimension. Unlike earlier results in the passive configuration, in the active configuration couples comprised of titanium alloys (NiTi and (beta-Ti) had higher RS values in the wet versus the dry state. For those archwire alloys evaluated, two empirical expressions were adduced that comprise the binding component, the yield strength or elastic limit, and the beam length, which implicitly represent the stiffness, flexibility, and interbracket distance.

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Coefficients of friction for arch wires in stainless steel and polycrystalline alumina bracket slots. I. The dry state

Cited by 119 publications

References 8 publications

Friction of Conventional and Silica-Insert Ceramic Brackets in Various Bracket-Wire Combinations

Friction of Conventional and Silica-Insert Ceramic Brackets in Various Bracket-Wire Combinations

Forces in the Presence of Ceramic Versus Stainless Steel Brackets with Unconventional vs Conventional Ligatures

Resistance to sliding of orthodontic appliances in the dry and wet states: Influence of archwire alloy, interbracket distance, and bracket engagement

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