The problem with the fluorescent tube was a 5 foot was 58 watt, you could not buy a tube with lower wattage, so if you needed the length to light a corridor then often the lighting was well over what was required to get the spread required. So with an electronic ballast the current was normally less than 58 watt, that was what it used with a magnetic ballast, also the electronic ballast made the tubes last longer, and the light output increased, so one did get slightly under 100 lumen per watt, so very little difference between fluorescent and LED. Main difference is the recycling of the old units, there are more nasty stuff in a LED tube, and as a dentist you will know how dangerous mercury is, and how we would not dream of putting it anywhere near ones mouth!
However since we can't buy fluorescent any more, we have no option but go to LED, however to simply fit LED tubes instead of fluorescent is not really the answer. One so many fluorescent fittings have HF electronic ballasts already fitted so many of the LED tubes will not work, and also a typical LED tube 5 foot is 22 watt and 2000 - 2500 lumen and the fluorescent was 58 watt and 5000 - 5600 lumen so it needs two LED tubes to get same light as one fluorescent.
And as already said often we did not need that much light anyway. So the whole idea of simply swapping tubes does not work, one needs to start from scratch and work out what lighting is required. I was surprised when visiting my son, his house is my old house, he had the defuser missing on the old 18 watt fluorescent fitting, the fitting I had converted from magnetic ballast to electronic ballast when making it an emergency fitting, but the LED replacement tube was working fine, he did not realise it was not a magnetic ballast.
It seems some LED tubes will work with electronic ballasts, I knew there were some specials designed for the old 2D fittings, but did not realise there are also some designed to would as straight tube replacements. As to if limited to low wattage I don't know. I remember testing caravan fluorescent fittings seem to remember 7 - 60 - 7 volt on early ones, but latter versions the heater not used so around 60 volt run but start was a lot higher, so not all HF ballasts are the same, so working with one HF ballast does not mean it will work with all.
So likely not a simple tube change, but a complete rethink on how to best light areas. I was against the idea of integral lamps, however my wife bought 3 outside carriage lamps, two used bulbs, and one integral, and the integral works so much better, mainly as light directed down to the floor where we want lighting, and the bulb faces up so light has to be reflected from the top back down. I would have said the integral is an expensive option on the long run, but she paid £2 each for bulb type and £4 for integral type, and I paid £11 for the bulbs, so integral worked out a lot cheaper, OK she got them in a sale, but it seems impossible to work out prices.
