All toothbrushes can damage your gums. It all depends on the length of time and pressure applied whilst brushing.
The recommended brushing time is 2 minutes and there is a recommendation that you only apply the pressure of
up to two minutes and with greater pressure up to 150 grams of pressure, which is about the weight of an orange.
“Although we found that you have to brush your teeth reasonably long and hard to get rid of the harmful plaque which causes dental diseases, our research shows that once you go beyond a certain point, you aren't being any more effective,” says Heaseman, in a news release. “You could be actually harming your teeth and gums.” (WebMD, 2003).
Too much brushing, or brushing too hard can damage the protective enamel on your teeth or irritate your gums and cause other oral health problems (McCracken et al. 2003).
There are electric toothbrushes on the market which provide a visual indicator that you are brushing too hard and indicates the amount of time you have been brushing.
One I have flashes a red light if you press too hard and vibrates every 30 seconds.
If you purchase a brush like this it will help to ensure that you brush for the required time and not too hard.
If you don’t have one of these brushes and you are unsure how to go about brushing your teeth, the best thing to do is to make an appointment with your dentist or dental hygienist who will be able to train you in the correct techniques and will show you approximately how much pressure you should be applying
McCracken, G. I., Janssen, J., Swan, M., Steen, N., De Jager, M., & Heasman, P. A. (2003). Effect of brushing force and time on plaque removal using a powered toothbrush. Journal of clinical periodontology, 30(5), 409-413. doi: 10.1034/j.1600-051X.2003.20008.x
WebMD (2003). Go Easy on Your Toothbrush; Less is More. Retrieved from: https://www.webmd.com/oral-health/news/20030620/go-easy-toothbrush