Orthodontic adhesives

1. A single component light-curable orthodontic adhesive comprising:

a curable resin monomer component, said curable resin monomer component comprising at least bisphenol A diglycidyl ether dimethacrylate, ethoxylated trimethylopropane triacrylate, ethoxylated bisphenol A dimethacrylate, and triethylene glycol dimethacrylate;

a quaternary curing initiator system comprising:

camphorquinone,

bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,

octyldimethylaminobenzoate, and

1,1′-azobis(cyanocyclohexane); and

filler,

wherein the single paste light-curable orthodontic adhesive has a working time (W) to curing time (C) ratio (W/C) of at least 10 to 30,

wherein said working time is expressed as a multiple of a five second interval that is visually determined as a point at which an approximately 2 mm×2 mm extruded sample of the single component light-curable orthodontic adhesive sufficiently hardens to a crusty consistency and undergoes a brittle fracture when cut in approximately 2 mm sections under a halogen operatory exam light positioned to provide 10,000±50 lux at the extruded sample on a white background, and

wherein said curing time is a duration of exposing the single component light-curable orthodontic adhesive to a curing light that is necessary to effect a shear bond strength greater than 7 MPa within 60 seconds after the single component light-curable orthodontic adhesive is applied to an etched and sealed bovine tooth.

2. The orthodontic adhesive of claim 1 , wherein said curable monomer component further includes at least one of the following: pyromellitic glycol dimethacrylate, glycidyl methacrylate, and glycerol dimethacrylate.

3. The orthodontic adhesive of claim 1 , further comprising a colorant.

4. The orthodontic adhesive of claim 3 , wherein the colorant includes at least one reversible dye.

5. The orthodontic adhesive of claim 4 , wherein the reversible dye is thermochromatic.

6. The orthodontic adhesive of claim 5 , wherein the reversible, thermochromatic dye has a readily visible, non-tooth colored color below its clearing temperature and is generally tooth colored at body temperature.

7. The orthodontic adhesive of claim 1 , further comprising a resin toughening component.

8. The orthodontic adhesive of claim 7 , wherein the resin toughening component is a methacrylated urethane resin.

9. The orthodontic adhesive of claim 8 , wherein the resin toughening component is an acrylic terminated polyurethane.

10. The orthodontic adhesive of claim 1 , wherein the quaternary curing initiator system consists essentially of camphorquinone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, octyldimethylaminobenzoate and 1,1′-azobis(cyanocyclohexane).

11. The orthodontic adhesive of claim 1 , wherein the W/C ratio is at least 12.

12. The orthodontic adhesive of claim 1 , wherein the W/C ratio is at least 14.

13. The orthodontic adhesive of claim 1 , wherein the W/C ratio is at least 20.

14. The orthodontic adhesive of claim 1 , wherein the curable resin monomer component comprises at least:

5 wt % to 20 wt % of bisphenol A diglycidyl ether dimethacrylate,

5 wt % to 20 wt % of ethoxylated trimethylopropane triacrylate,

15 wt % to 30 wt % of ethoxylated bisphenol A dimethacrylate, and

40 wt % to 60 wt % of triethylene glycol dimethacrylate, wherein wt % is based on the total weight of the curable resin monomer component.

15. The orthodontic adhesive of claim 1 , wherein the curing light is a halogen curing light having an 850 Mw/cm 2 output in the 400-505 nm range.

16. The orthodontic adhesive of claim 1 , wherein the quaternary curing initiator system comprises:

0.04 wt % to 0.05 wt % camphorquinone,

0.5 wt % to 0.6 wt % bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,

0.06 wt % to 0.07 wt % octyldimethylaminobenzoate, and

0.2 wt % 1,1′-azobis(cyanocyclohexane), wherein wt % is based on the entire weight of the single component light-curable orthodontic adhesive.

17. A single component light-curable orthodontic adhesive comprising:

a curable resin monomer component, said curable resin monomer component comprising at least bisphenol A diglycidyl ether dimethacrylate, ethoxylated trimethylopropane triacrylate, ethoxylated bisphenol A dimethacrylate, and triethylene glycol dimethacrylate;

a quaternary curing initiator system comprising:

camphorquinone,

bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,

octyldimethylaminobenzoate, and

1,1′-azobis(cyanocyclohexane); and

filler,

wherein the single component light-curable orthodontic adhesive will not harden to a crusty consistency for about 70 seconds to about 100 seconds when exposed to a halogen operatory exam lamp positioned at a distance providing 10,000±50 lux output for an approximately 2 mm×2 mm×20 mm extruded sample of the adhesive on a white background; and wherein the single component light-curable orthodontic adhesive is capable of exhibiting a shear bond strength, when applied to an etched and sealed bovine tooth, of greater than 7 MPa within 60 seconds after light curing for a duration of 2 seconds to 5 seconds, as measured using a halogen curing light having an 850 mW/cm 2 output in the 400-505 nm range to irradiate the adhesive applied to an etched and sealed bovine tooth.

18. A single component light-curable orthodontic adhesive comprising:

a curable resin monomer component including more than one different curable resin monomer;

a quaternary curing initiator system comprising:

camphorquinone,

bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,

octyldimethylaminobenzoate, and

1,1′-azobis(cyanocyclohexane); and

filler,

wherein the single paste light-curable orthodontic adhesive has a working time (W) to curing time (C) ratio (W/C) of at least 10 to 30,

wherein said working time is expressed as a multiple of a five second interval that is visually determined as a point at which an approximately 2 mm×2 mm extruded sample of the single component light-curable orthodontic adhesive sufficiently hardens to a crusty consistency and undergoes a brittle fracture when cut in approximately 2 mm sections under a halogen operatory exam light positioned to provide 10,000±50 lux at the extruded sample on a white background,

wherein said curing time is a duration of exposing the single component light-curable orthodontic adhesive to a curing light that is necessary to effect a shear bond strength greater than 7 MPa within 60 seconds after the single component light-curable orthodontic adhesive is applied to an etched and sealed bovine tooth,

wherein said curable monomer component includes at least four of the following:

bisphenol A diglycidyl ether dimethacrylate, ethoxylated bisphenol A dimethacrylate, ethoxylated trimethylopropane triacrylate, pyromellitic glycol dimethacrylate, triethylene glycol dimethacrylate, glycidyl methacrylate, and glycerol dimethacrylate, and

wherein the curable resin monomer component comprises at least

5 wt % to 20 wt % of bisphenol A diglycidyl ether dimethacrylate,

5 wt % to 20 wt % of ethoxylated trimethylopropane triacrylate,

15 wt % to 30 wt % of ethoxylated bisphenol A dimethacrylate, and

40 wt % to 60 wt % of triethylene glycol dimethacrylate, wherein wt % is based on the total weight of the curable resin monomer component.