There are lots of myths when it comes to regular scaling of the teeth such as, it causes the teeth to become loose or it peels off the first layer of enamel, it loosens up your teeth. Well the fact is scaling/teeth cleaning is done with an ultrasonic scaler which operates by vibrations, it has no potency of drilling the teeth at all. It just removes the debris,deposits and stains from the teeth by the motions of vibrations.
What makes you think your teeth became loose? Well, the deposits over period of long time makes a hard semi calcified layer between the gums and teeth hence the gums are detached and recessed from the teeth so when the calculus/tartar/deposits are removed from the gum-line it gives you the feeling of loose teeth, but that is "bad support" of the teeth that we are removing. In few weeks the gums get attached back to the teeth and the mouth is healthy, free of deposits and tartar. Hence we are just removing the "bad support " which ultimately would have left you with no teeth!!!
Hence, one should get scaling/cleaning of teeth twice in a year. A six monthly visit to your dentist can help you have all your teeth till you live...!