Kelli Agee

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Papers

Water distribution in dentin matrices: Bound vs. unbound water

Dental materials : official publication of the Academy of Dental Materials, Jan 19, 2015

This work measured the amount of bound versus unbound water in completely-demineralized dentin. D... more This work measured the amount of bound versus unbound water in completely-demineralized dentin. Dentin beams prepared from extracted human teeth were completely demineralized, rinsed and dried to constant mass. They were rehydrated in 41% relative humidity (RH), while gravimetrically measuring their mass increase until the first plateau was reached at 0.064 (vacuum) or 0.116gH2O/g dry mass (Drierite). The specimens were then exposed to 60% RH until attaining the second plateau at 0.220 (vacuum) or 0.191gH2O/g dry mass (Drierite), and subsequently exposed to 99% RH until attaining the third plateau at 0.493 (vacuum) or 0.401gH2O/g dry mass (Drierite). Exposure of the first layer of bound water to 0% RH for 5min produced a -0.3% loss of bound water; in the second layer of bound water it caused a -3.3% loss of bound water; in the third layer it caused a -6% loss of bound water. Immersion in 100% ethanol or acetone for 5min produced a 2.8 and 1.9% loss of bound water from the first laye...

Effects of quaternary ammonium-methacrylates on the mechanical properties of unfilled resins

Dental materials : official publication of the Academy of Dental Materials, 2014

Adding antimicrobial/anti-MMP quaternary ammonium methacrylates (QAMs) to comonomer blends should... more Adding antimicrobial/anti-MMP quaternary ammonium methacrylates (QAMs) to comonomer blends should not weaken the mechanical properties of dental resins. This work evaluated the degree conversion and mechanical properties of BisGMA/TEGDMA/HEMA (60:30:10) containing 0-15 mass% QAMs A-E (A: 2-acryloxyethyltrimethyl ammonium chloride; B: [3-(methacryloylamino)propyl]trimethylammonium chloride; C: [2-(methacryloxy)ethyl] trimethyl ammonium chloride; D: diallyldimethyl ammonium chloride; E: 2-(methacryloyloxy) ethyltrimethyl ammonium methyl sulfate. Unfilled resins with and without QAM were placed on ATR-FTIR and light-polymerized for 20s in a thin film at 30°C. Unfilled resin beams were casted from square hollow glass tubings. Half of the beams were tested after 3 days of drying (control); the other half were tested wet after 3 days of water storage. Addition of QAMs in control resins significantly increased conversion 600 s after light termination, with the exception of 5% MAPTAC (p<...

Durability of Resin-Dentin Bonds to Water- vs. Ethanol-saturated Dentin

Journal of Dental Research, 2009

Higher 24-hour resin-dentin bond strengths are created when ethanol is used to replace water duri... more Higher 24-hour resin-dentin bond strengths are created when ethanol is used to replace water during wet bonding. This in vitro study examined if ethanol-wet-bonding can increase the durability of resin-dentin bonds over longer times. Five increasingly hydrophilic experimental resin blends were bonded to acid-etched dentin saturated with water or ethanol. Following composite build-ups, the teeth were reduced into beams for 24-hour microtensile bond strength evaluation, and for water-aging at 37 degrees C for 3, 6, or 12 months before additional bond strength measurements. Although most bonds made to water-saturated dentin did not change over time, those made to ethanol-saturated dentin exhibited higher bond strengths, and none of them fell over time. Decreased collagen fibrillar diameter and increased interfibrillar spacing were seen in hybrid layers created with ethanol-wet-bonding. Increases in bond strength and durability in ethanol-wet-bonding may be due to higher resin uptake and better resin sealing of the collagen matrix, thereby minimizing endogenous collagenolytic activities.

Effects of Resin Hydrophilicity on Dentin Bond Strength

Journal of Dental Research, 2006

The purpose of this study was to determine if hydrophobic resins can be coaxed into dentin wet wi... more The purpose of this study was to determine if hydrophobic resins can be coaxed into dentin wet with ethanol instead of water. The test hypothesis was that dentin wet with ethanol would produce higher bond strengths for hydrophobic resins than would dentin wet with water. This study examined the microtensile bond strength of 5 experimental adhesives (50 wt% ethanol/50% comonomers) of various degrees of hydrophilicity to acid-etched dentin that was left moist with water, moist with ethanol, or air-dried. Following composite buildups, hourglass-shaped slabs were prepared from the bonded teeth for microtensile testing. For all 3 types of dentin surfaces, higher bond strengths were achieved with increased resin hydrophilicity. The lowest bond strengths were obtained on dried dentin, while the highest bond strengths were achieved when dentin was bonded moist with ethanol. Wet-bonding with ethanol achieved higher bond strengths with hydrophobic resins than were possible with water-saturated matrices.

Effect of wet vs. dry testing on the mechanical properties of hydrophilic self-etching primer polymers

European Journal of Oral Sciences, 2007

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