A Survey of Intensity of Quartz-Tungsten-Halogen Dental Lights Used in Private Practices in Egypt
Authors: Enas Mobarak, Wafa El-Badrawy and Omar El-Mowafy
Abstract: Purpose: the aim of this investigation was to determine light intensity of QTH light curing units used in a sample of dental offices in Cairo. Methods: Dental offices were selected to participate following specific criteria for inclusion. Once enrolled a member of the research team visited the office to conduct the survey. One digital light meter (Curite, EFOS) and one analog (Optilux, model 100, SDS/Kerr) were used for the measurements. They were calibrated daily against one another to ensure consistency. At each office surveyed six light intensity measurements were made from each unit following a short warm up period. Age and make of curing unit(s), maintenance history, curing cycle used with composites as well as availability of a light meter in the office were recorded. Mean light intensity for each curing unit was calculated and data statistically-analyzed. Results: A total of 113 QTH light curing units found in 100 dental offices were tested. These were made by 32 different manufacturers. Light intensity varied considerably among the offices with mean measurements ranging from 79.2 – 946.2 mW/cm2. A considerable number (41%) of the units had mean intensity values less than 300 mW/cm2. Curing units with intensity less than 200 mW/cm2 composed 25% of all units while those between 400-499 mW/cm2 were 21%. Most units were from 1 to10 year-old with 20% being more than 10 year-old. Age of light unit significantly decreased intensity (P<0.01). Only two of the dental offices visited had light meters. Dentists used exposure time of approximately 32 sec/increment on average. Conclusions: A considerable number of the tested light units emitted light with intensity below critical levels. Dentists in Cairo should be encouraged to periodically examine light intensity of units in their offices and carry out maintenance services as necessary. Clinical Relevance. A considerable number of dental offices in Cairo (46%) operated QTH light curing units that emitted light with intensity below critical levels.