Hi my 7 month old started teething At 4 months and now has 6 teeth.its been a rollercoaster as she couldn't grip anything at first we used The teetha crystals a lot and they worked amazing and still do in between the neurofen and Calpol. The big squeaky Sophie giraffe toy has been her favourite to 'scratch the itch' now she can grip also putting ice in the clevamama clevafeed was a lifesaver when I discovered it.
I think the rings that you can freeze or chill are good. My twins love the matchstick monkey toy