Factors affecting light transmission of single-use, plastic light-curing tips

Recently, manufacturers introduced presterilized, single-use, plastic light-curing tips to be used either routinely or on patients with known or questionable communicable health concerns. The purpose of this study was to examine the effect of these single-use tips on light transmission compared to conventional fiber-optic bundles in a variety of commercial light-curing units. Also, the effects of surface contact with the plastic tips (human tissues, reflective or opaque media, and barrier films) were evaluated. Where applicable, single-use tips from two sources (Caulk/Dentsply and Demetron) were placed in commercial curing units (Optilux 150 and 500, MAX 100, Spectrum Curing Light, and 3M XL-3000), and the intensity was compared to that of the conventional glass curing tip used with that specific curing unit. Intensity readings were also made for 6 continuous minutes using plastic tips in a high-intensity curing unit to simulate veneer bonding. If the sides of the plastic tip came in contact with the operator's fingers or the patient's tongue and/or check during a clinical procedure, a lowering of transmitted light intensity resulted. The glow emitted from the sides of the tip when in use may be annoying to the operator. To prevent this glare, the operator may be tempted to treat the sides of the tip by painting, applying a thin polymer barrier, abrasion, or wrapping in an opaque reflective material (aluminum foil). A significant decrease in light intensity can result if plastic curing tips contact oral tissues or bare hands. Application of thin polymer barriers was found to significantly reduce light transmission value. Also, surface modification (coating with paint or surface scratches) was found to greatly reduce light intensity levels, while wrapping the tip in aluminum foil produced a very small increase. Results indicated that transmitted light intensity with use of plastic tips was dependent upon both the brand of plastic tip tested and the different photocuring units. Either a slight increase or a slight decrease in intensity was noted. Plastic tips did not degrade in transmitted intensity when exposed to the heat produced during a simulated veneering scenario. In summary, use of plastic, single-use light-curing tips can provide adequate intensity for photoactivated restorative techniques; however, the clinician must be aware of specific, clinically relevant limitations with their use. Clinicians must also note that these tips are not designed for re-use.