PubMed · 8754458
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M Staninec. 1996. Understated efficacy?. https://doi.org/10.14219/jada.archive.1996.0362
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OBJECTIVE: To investigate the effectiveness of chargeable light curing units and their ability to sustain a high radiant output following successive discharge cycles. SETTING: University based research investigation assessing the output intensity of three battery powered light activation units and the effect of successive discharge cycles, without intervening periods of recharging, on light output and depth of cure of resin composite. MATERIALS AND METHODS: Mean light intensity (mW/cm2), through a 4 mm aperture, was measured with a computer based radiometer. Two commercially available resin composites (one hybrid and one microfilled resin) were used for the depth of cure determinations using a digital penetrometer. RESULTS: Depths of cure were significantly greater for the hybrid resin composite. Output intensity diminished over the period of battery discharge for two of the three units and this finding was paralleled in the depth of cure results. The battery light units tested varied significantly with regard to their length of discharge cycle and recharge times from complete discharge. CONCLUSIONS: Output intensity diminishes over the period of battery discharge for some makes of battery light units. However, many other factors including handpiece size and weight and unit cost and reliability are important considerations when choosing a unit.
BACKGROUND AND OBJECTIVE: The potential benefits of the effects of lasers on dental tissues have yet to be realized but may be brought closer through the availability of a suitable laser. The objective of this project is to examine the surface morphological changes resulting from hydrogen fluoride (HF) laser radiation on tooth and restorative material surfaces. STUDY DESIGN/MATERIALS AND METHODS: A hydrogen fluoride laser emitting at 2.9 microns is used to interact with a range of dental hard tissue and restorative materials. The surface morphological changes induced by 100 mJ pulses of < 1 microsecond duration is studied using a SEM. RESULTS: The irradiated surfaces displayed microstructures similar to those of a mechanically fractured surface with no evidence of melting. CONCLUSION: This study suggests that tissue is removed by microexplosion, leaving a surface free from thermal damage with surface characteristics that would appear to facilitate the adhesion of restorative materials.
This article describes a restorative technique for the formation of composite cores for artificial crowns. The procedure uses a semirigid matrix with reverse carving to form the cores on substantially compromised teeth. The matrix allows the placement of the composite under pressure to reduce voids and gaps and permits completion of multiple cores simultaneously. Reverse carving enables development of a common axis for multiple cores. The dentist can perform the tooth preparation for the crown at the time of the core restoration. The effort commonly applied to developing tooth morphologic features in the core can be invested instead in the formation of the interim restoration. The remaining tooth structure, pin or post placement, and location of the finish line can be evaluated with the insight of a crown foundation and not merely as a traditional restoration.