One-component self-etching adhesive

Information

  • Patent Application
  • 20070244215
  • Publication Number
    20070244215
  • Date Filed
    October 10, 2006
    18 years ago
  • Date Published
    October 18, 2007
    17 years ago
Abstract
A one-part, self-etching dental adhesive having improved performance such as adhesion performance with a simple one-coat application, without the need of separate acid-etching, a priming pre-treatment, or bonding step. The invention provides such improvements due to a function of the pH balance of the system in combination with an acid stable photoinitiating system. More specifically, the performance and pH balance is achieved through the employment of a hydrolytically stable, acidic, high-strength adhesive monomer (such as PENTA), with a stable, bifunctional, hydrophilic monomer (such as AHPMA) that yields greater crosslinking.
Description
PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

For One-component Visible Light Cure Self-Etching Adhesive (1P-SEA) according to the invention, it is indicated to bond VLC composite/compomer direct restorations to human teeth substrate (enamel and dentine) without the need of separate acid-etching or priming pre-treatment teeth bonding step. When used with a separate Self-Cure Activator component, the 1P-SEA can also bond for cemented indirect restorations (prefabricated metal/porcelain/composite Inlays/Onlays/Veneers/Crowns/Bridges) to human teeth substrate (enamel and dentine) without separate acid etching or priming pre-treatment step. In addition, 1P-SEA can also be used as a cavity varnish.









TABLE 1







Prototype Formulation of One-Component Self-Etching Adhesive











Raw


Formulation
Preferred


Material
Chemical Name
CAS #
Ranges
% Weight














UDMA
2-Methyl-acrylic acid 1-methyl-2-{3,5,5-
105883-40-7
 5–15
10.50



trimethyl-6-[1-methyl-2-(2-methyl-



acryloyloxy)-ethoxycarbonyl amino]-



hexylcarbamoyloxy}-ethyl ester


PENTA
2-Methyl-acrylic acid 4-(2-methyl-acryloyloxy)-
87699-25-0
 8–20
12.80



2,2,3-tris-(2-methyl-acryloyloxymethyl)-3-



phosphonooxymethyl-butyl ester


HEMA
2-Methyl-acrylic acid 2-hydroxy-ethyl ester
868-77-9
0–5
3.20


AHPMA
2-Methyl-acrylic acid 3-acryloyloxy-2-hydroxy-
1709-71-3
 5–15
9.50



propyl ester


TMPTMA
2-Methyl-acrylic acid 2,2-bis-(2-methyl-
3290-92-4
0–5
1.60



acryloyloxymethyl)-butyl ester


L-TPO
(Diphenyl-phosphinoyl)-(2,4,6-trimethyl-
75980-60-8
0.1–2.0
0.99



phenyl)-methanone


CQ
Bicyclo [2,2,1] heptane-2,3 dione, 1,1,7-
10373-78-1
0.05–0.50
0.19



trimethyl


DMABN
4-Dimethylamino-benzonitrile
1197-19-9
0.1–1.2
0.79


BHT
Phenol, 2,6-bis (1,1-dimethylethyl-4-methyl)
128-37-0
0.01–0.2 
0.13


CAF
Hexadecyl-ammonium; fluoride
3151-59-5
  0–1.0
0.30


Water
Water
7732-18-5
 5–20
12.60


Acetone
2-Propanone
67-64-1
20–60
47.40


Total



100









Physical Properties and Characteristics

True one-component self-etching bonding agent in both bottle and unit dose package


No mixing or rinsing requirement prior to application


One-coat/One-step simple and robust technique


VLC direct bond strength equal or better than Xeno III and other 2-component competitors


Indirect bond strength (when used with separate SCA component) equivalent to that of P&B NT/SCA Dual Cure adhesive


Low film thickness (<15 μm)


Fluoride releasing


Microleakage at least as good as the current P&B NT and Xeno III systems


Comparison to Competitive Products

In Vitro shear bond strength before and after thermocycling was tested on 1P-SEA and other dental adhesives. The data is shown in Tables 2, 3, 4 and 7. Seven dental adhesives were selected: 1P-SEA (Dentsply), Xeno III (Dentsply), Prime & Bond NT (P&B NT, Dentsply), Prompt L-Pop (L-Pop, 3M ESPE), ClearFil SE Bond (SE, Kuraray), One-up Bond F (OBF, Tokuyama), i-Bond (IB, Heraeus Kulzer).


In general, the previous adhesion data and graphs indicate that the 1P-SEA prototypes exhibit comparable performance to the leading currently marketed, 2-component, self-etching adhesive products.


The single-component self-etching adhesive (1P-SEA) prototype demonstrates an improvement to the existing commercial self-etching adhesive products. The new self-etching adhesive material achieves good adhesion performance with a simple one-coat application, without the need of separate acid-etching, a priming pre-treatment, or bonding step.


1P-SEA is a light cured self-etching adhesive contained in a single package (bottle or single unit-dose) which is applied onto dentin and/or enamel surfaces to bond direct light cure composite restorations. The 1P-SEA is easily differentiated from the prior art which divides the active ingredients of the composition into two or more parts (in different packages) to avoid composition degradation or polymerization. The 1P-SEA is designed to overcome the single package storage stability issues through optimization of the formulation to provide competitive self-etching adhesion performance without presenting the stability issues commonly associated with other self-etching adhesives contained in a single package.


The improved performance in conjunction with other feature/benefits previously identified in the 1P-SEA is a function of the pH balance of the system in combination with an acid stable photoinitiating system. More specifically, the performance and pH balance is achieved primarily through the employment of the hydrolytically stable, acidic, high-strength adhesive monomer (PENTA), with a stable, bifunctional, hydrophilic monomer (AHPMA) that yields greater crosslinking.


Optimally, a minimal amount of water has been incorporated into a water-miscible polar aprotic organic solvent, e.g., acetone to facilitate etching. In addition, micro- or nanosized fillers and fluoride-releasing agents can also be incorporated into the 1P-SEA composition to enhance performance and inhibit secondary caries through releasing fluoride.


Optionally, a separate self-curing activator component can be utilized with the 1P-SEA to facilitate the use of this product for indirect self cure applications (prefabricated metal/porcelain/composite Inlays/Onlays/Veneers/Crowns/Bridges). The 1P-SEA exhibits superior bonding performance over other single component self-etching (prior art) products. More specifically, the 1P-SEA yields high initial and sustained long-term bonding performance (enamel bond strength≧20 MPa and dentin bond strength≧15 MPa). As previously discussed, the new 1P-SEA product achieves good adhesion with a simple “one-coat” one-step application technique, without separate acid-etching or priming.


The bonding performance of the 1P-SEA is sustained after excessive thermal stressing (5000 cycles at 55° C.). In addition, this product has demonstrated excellent shelf storage stability withstanding 3 weeks at 50° C. without a significant decrease in performance while—Bond (Kulzer), the only commercial single-component SEA gelled after storage at 50 248 C for a week. In comparison with current commercial self-etching adhesive products, the 1P-SEA exhibits comparable or superior bonding performance, storage stability and shelf life.


Table 5 shows 24-hr dentin shear bond strength of 1P-SEA after storage at different temperatures and for different time duration. Table 6 compares bond strength of three different experimental 1P-SEA differing only in aromatic amines. DHEPT and EDAB are two most commonly used co-initiators for CQ. The formulations containing either DHEPT or EDAB did not lead to acceptable balanced properties. Only the formulation incorporating DMABN exhibits the superior balance of bond strength, storage stability and compatibility with different curing lights, e.g., QTH light and LED light. DMABN is the first time ever used in any dental adhesive.









TABLE 5







24 hr Dentin SBS of 1P-SEA in MPa (Mean ± Stdev.)











Time (week)
37° C.
45° C.
50° C.
60° C.














0
17.6 ± 5.2
17.6 ± 5.2
17.6 ± 5.2
17.6 ± 5.2


1
NT
NT
NT
18.8 ± 7.5


1.5
NT
NT
NT
17.5 ± 4.6


2
NT
NT
17.8 ± 5.8
12.3 ± 4.2


3
NT
19.4 ± 9.2
18.1 ± 7.2
10.8 ± 3.5


3.5
NT
16.6 ± 3.8
17.9 ± 6.8
NT


4
NT
17.8 ± 5.1
8.2 (2.2)
NT


6
16.8 ± 7.0
15.0 ± 5.6
NT
NT


7
NT
16.7 ± 5.0
NT
NT


8
24.0 ± 2.8
17.5 ± 5.2
NT
NT


10
15.5 ± 4.8
 7.3 ± 3.9
NT
NT


11
17.5 ± 4.6
NT
NT
NT


12
12.7 ± 3.8
NT
NT
NT
















TABLE 6







24 hr Shear Bond Strength of 1P-SEA containing Different Co-initiators











1P-SEA containing
1P-SEA containing
1P-SEA containing


Sample I.D.
DMABN
DHEPT
EDAB















Human Dentin
RT stored
QTH Light
23.2 (3.9)
NT
17.0 (7.5)


SBS (MPa):

LED Light
22.0 (4.0)
NT
15.6 (5.7)


Mean (SD)
50° C. 3 weeks
QTH Light
15.3 (4.2)
NT
14.5 (6.9)




LED Light
15.8 (6.1)
NT
16.8 (6.8)


Human Ename1
RT stored
QTH Light
26.4 (5.3)
13.5 (6.7)
32.7 (7.2)


SBS (MPa):

LED Light
32.0 (3.0)
NT
30.1 (7.3)


Mean (SD)
50° C. 3 weeks
QTH Light
26.7 (5.3)
NT
 7.6 (2.0)




LED Light
35.3 (7.9)
NT
 24.8 (13.3)









SEA exhibits excellent shear bond strength on both dentin and enamel when used with Self-Cure Activator to bond resin cements (i.e. Calibra). Table 7 illustrates that SEA has improved bonding performance in comparison to Prime & Bond NT for bonding Calibra to tooth substrates.


Packaging Addendum

The minimum design specifications for SEA require a unit-dose packaging format similar to the system currently used for Prime & Bond® NT. Dentsply International, under U.S. Pat. No. 6,372,816 has patented this system (packaging), Waltz, et al., as of Apr. 16, 2002. The ideal requirements for packaging are defined as “integral brush unit-dose” (IB unit-dose). Patent application Ser. No. 10/668,946, Pierson, et al., Sep. 23, 2003, has been submitted for the IB unit-dose packaging under case number LDC-922-E.

Claims
  • 1. A one-part, self-etching dental adhesive comprising a hydrolytically stable, acidic, high-strength adhesive monomer and a stable, bifunctional, hydrophilic monomer.
  • 2. An adhesive as in claim 1, wherein said acidic monomer is PENTA.
  • 3. An adhesive as in claim 1, wherein said bifunctional, hydrophilic monomer is AHPMA.
RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 60/618,649 filed on Oct. 14, 2004.

Continuations (1)
Number Date Country
Parent 11402127 Apr 2006 US
Child 11545669 US