Lothar G Huck | PubMed Health

PubMed2003

Plasma arc curing of ceramic brackets: an evaluation of shear bond strength and debonding characteristics.

The aim of this in vitro investigation was to evaluate bond strength and debonding characteristics when a xenon plasma arc curing light is used to bond polycrystalline and monocrystalline ceramic brackets. Brackets were bonded to 240 extracted bovine mandibular incisors with a composite adhesive. Curing intervals of 1, 3, and 6 seconds were chosen for curing with the plasma arc light, and the control group was cured at 10 seconds per bracket with a conventional halogen light. Debonding was performed on a universal testing machine and according to the bracket manufacturers' recommendations. Both the polycrystalline and the monocrystalline brackets consistently debonded at the bracket-adhesive interface, regardless of debonding method, curing interval, or curing light. No enamel fractures were observed after debonding. Bracket fractures were rare and did not affect debonding. Bond strength was significantly higher for the monocrystalline brackets (P <.0001): mean shear bond strength ranged between 9.68 +/- 2.17 MPa (plasma arc curing light, 1 sec curing interval) and 10.73 +/- 3.22 MPa (halogen light, 10 sec curing interval) for the polycrystalline brackets and between 19.85 +/- 2.97 MPa (plasma arc curing light, 1 sec curing interval) and 22.94 +/- 3.20 MPa (plasma arc curing light, 3 sec curing interval) for the monocrystalline brackets. Significant differences were also found for the curing methods used (P =.047). A curing interval of 3 seconds with the plasma arc curing light is recommended for both polycrystalline and monocrystalline ceramic brackets.

Analysis of Variance↗

PubMed2002

Plasma arc curing lights for orthodontic bonding.

Xenon plasma arc lights were introduced recently for light-cured orthodontic bonding. Compared with a conventional tungsten-quartz-halogen light source, these high-intensity lights promise a dramatic reduction in curing time. The purpose of this in vitro investigation was to evaluate bond strength with 2 commercially available plasma arc lights and reduced curing intervals. Brackets were bonded to 150 extracted human teeth (75 premolars, 75 incisors) with a composite adhesive. Intervals of 2 and 6 seconds were used for curing with the plasma arc lights; a control group was bonded with a halogen light source and 20 seconds of light exposure per bracket. Bond strength testing was performed with a universal testing machine. A substantial reduction in curing time was possible with both plasma arc units. Significantly lower bond strength values were found for premolar brackets bonded with plasma arc curing lights and the shortest curing interval of 2 seconds compared with the longer curing time of 6 seconds or the standard curing time with the halogen light. Although 2 seconds of curing might be adequate to achieve acceptable bond strength values for the incisors, the Weibull analysis indicated a higher probability of bond failure for premolar brackets in particular. Six seconds of curing time is recommended for bonding stainless steel brackets with xenon plasma arc light sources.

Analysis of Variance↗