WET-PREP

K961822 · Bisco, Inc. · KLE · Jun 11, 1996 · Dental

Device Facts

• Record ID: K961822
• Device Name: WET-PREP
• Applicant: Bisco, Inc.
• Product Code: KLE · Dental
• Decision Date: Jun 11, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 872.3200
• Device Class: Class 2

Intended Use

WET-PREP is used to re-wet dried dentin following acid etching and drying of the prepared cavity. Following etching the dentist typically air dries the etched enamel to check that a chalky-white appearance is present indicating that etching has occurred. At this point the dentin and enamel are too dry for effective penetration of subsequently applied primers. Hydrophilic primers will not effectively penetrate the dried collapsed collagen layer. If the primer is unable to penetrate through collapsed collagen an effective seal will not occur and post-operative sensitivity is likely to result. If WET-PREP is applied prior to application of the primers, it will effectively re-wet the collapsed collagen and allow for penetration of the hydrophilic primers through the moist collagen network. Enhancement of penetration of primers will improve the seal the restorative material makes with the prepared tooth. Since it is well known that microleakage is the predominant reason for post-operative sensitivity it is reasonable to assume an increase in sensitivity ought to result from the use of these products.

Device Story

WET-PREP is an aqueous re-wetting agent (dentin conditioner) used by dentists during restorative procedures. Following acid etching and air-drying of a tooth cavity, the dentin surface often becomes desiccated, causing collagen fiber collapse which inhibits primer penetration. The dentist applies WET-PREP to the prepared tooth surface to re-hydrate the collagen network. This ensures the surface remains moist, allowing subsequent application of hydrophilic dentin adhesives (e.g., ALL-BOND 2) to penetrate effectively. By facilitating proper primer penetration, the device improves the seal between the restorative material and the tooth, reducing microleakage and potential post-operative sensitivity. The device is applied chairside by a dentist.

Clinical Evidence

Bench testing only. Shear bond strength studies compared WET-PREP treated teeth to untreated and HEMA-BENZ treated teeth. Results showed WET-PREP significantly improved shear bond strength of air-dried dentin (four-fold increase). No statistically significant difference (p=0.05, t=1.29) found between WET-PREP treated teeth and those handled in a clinically acceptable fashion, indicating no interference with bonding. WET-PREP treated teeth showed significantly greater shear bond strength compared to HEMA-BENZ treated teeth (p=0.5, t=3.39).

Technological Characteristics

Aqueous solution containing approximately 35% hydroxyethyl methacrylate (HEMA), <0.5% sodium fluoride, and benzalkonium chloride. Acts as a re-wetting agent for dentin. Standalone liquid application.

Indications for Use

Indicated for re-wetting dried dentin following acid etching and drying of a prepared dental cavity to facilitate the penetration of hydrophilic primer resins.

Regulatory Classification

Identification

A resin tooth bonding agent is a device material, such as methylmethacrylate, intended to be painted on the interior of a prepared cavity of a tooth to improve retention of a restoration, such as a filling.

Predicate Devices

• Bisco DENTIN CONDITIONER™
• HEMA-BENZ™

Submission Summary (Full Text)

{0}

BISCO, INC., 1500 W. Thorndale Ave., Itasca, IL 60143
510(k) submission for WET-PREP™
K961822
16

# 510(k) SUMMARY

As Required By the Safe Medical Devices Act of 1990

JUN 11 1996

## IDENTIFICATION OF THE LEGALLY MARKETED PREDICATE DEVICE

### PREDICATE DEVICE

**Bisco DENTIN CONDITIONER™**

DENTIN CONDITIONER is an aqueous solution of hydroxyethyl methacrylate (HEMA), and succinic acid-hydroxyethyl methacrylate (SA-HEMA). The product was used at a time when acid etching dentin was unheard of. The product was intended to diffuse into the dentin smear layer and enhance the mechanical bond of subsequently applied bonding resins. The supporting hypothesis was sound in that aqueous solutions ought to easily penetrate the hydrophilic smear layer. After evaporation of the water solvent the acrylic monomers could then wet and bond to the relatively hydrophobic bonding resins (bis-GMA). Both the conditioners and bonding resins could polymerize together effecting a seal of the cut dentin.

### PREDICATE DEVICE (cont).

**HEMA-BENZ™**

HEMA-BENZ is functionally and chemically similar to DENTIN CONDITIONER noted above. The product is intended to perform identical service but HEMA-BENZ is also referred to as a desensitizer. Desensitization, if occurs at all, is due to the indirect effect of enhanced wetting of subsequent applications of primer resins. That is, reduction of sensitivity is due to the enhanced seal provided by the primers, the enhancement of the seal occurs through improved wetting provided by the products in question.

### DESCRIPTION OF APPLICANT DEVICE

**WET-PREP™**

WET-PREP is an aqueous solution of hydroxyethyl methacrylate. Hence, it is an aqueous re-wetting agent (dentin conditioner) that is applied to acid etching tooth structure, by the dentist following prior to application of a hydrophilic dentin adhesive such as ALL-BOND 2. The purpose of WET-PREP is to keep the dental cavity preparation adequately moist before the dentist restores the lost tooth structure.

It is well known that ALL-BOND 2 and similar hydrophilic primer resin systems are most effective when applied to moist dentin as in the so-called wet technique¹. Some dentists have had difficulty determining exactly how wet to leave the dentin prior to application of hydrophilic primers. Brief drying with an air syringe prior to primer application often leads to desiccation of dentin with resultant collapse of collagen fibers. Collapsed collagen presents an effective barrier to penetration of primers.

Using the WET-PREP technique, the dentist can dry the cavity preparation following acid etching to assess the degree of enamel etching without fear of affecting the primer bond. The dentist simply re-wets with WET-PREP prior to application of the hydrophilic primer. WET-PREP precludes asking the familiar question, “How wet is wet?”

{1}

BISCO, INC., 1500 W. Thorndale Ave., Itasca, IL 60143
510(k) submission for WET-PREP™
17

# INTENDED USES OF APPLICANT DEVICE

WET-PREP is used to re-wet dried dentin following acid etching and drying of the prepared cavity. Following etching the dentist typically air dries the etched enamel to check that a chalky-white appearance is present indicating that etching has occurred. At this point the dentin and enamel are too dry for effective penetration of subsequently applied primers. Hydrophilic primers will not effectively penetrate the dried collapsed collagen layer. If the primer is unable to penetrate through collapsed collagen an effective seal will not occur and post-operative sensitivity is likely to result.

If WET-PREP is applied prior to application of the primers, it will effectively re-wet the collapsed collagen and allow for penetration of the hydrophilic primers through the moist collagen network. Enhancement of penetration of primers will improve the seal the restorative material makes with the prepared tooth. Since it is well known that microleakage is the predominant reason for post-operative sensitivity it is reasonable to assume an increase in sensitivity ought to result from the use of these products.

# SCIENTIFIC CONCEPTS and SIGNIFICANT PERFORMANCE CHARACTERISTICS

WET-PREP is an aqueous solution of hydroxyethyl methacrylate (approx. 35%) with a small amount (&lt;0.5%) of sodium fluoride and benzalkonium chloride. This solution has the ability to easily penetrate etched dentin and enamel and will help to prevent desiccation of the etched surface prior to application of primer resins. That is, after the etched enamel/dentin is dried to determine the quality of the etch, the dentist can re-wet the cut tissue with WET-PREP without concern for desiccation. The HEMA solution will keep the cut surface moist until application of hydrophilic primers.

It was found that WET-PREP significantly improved (greater than four fold increase) the shear bond strength of air dried dentin. This is a good indication of the product's efficacy. Desiccated dentin could be reconstituted so no significant difference could be found between treated teeth and those that were handled in a clinically acceptable fashion.

It was found that there was no statistically significant difference (p=0.05, t=1.29) between the shear bond strength of WET-PREP treated teeth and those left untreated. This was taken as an indication that WET-PREP did not significantly interfere with the bonding mechanism of the primer resins and the prepared tooth. However, WET-PREP treated teeth were found to have significantly greater shear bond strength when compared to HEMA-BENZ treated teeth

(p=0.5, t=3.39).

James L. Sandrik, Ph.D
Bisco, Inc.
Itasca, IL 60143

May 8, 1996