I didn't mention it in the post, but I'm using the albumentations module. I rotate, shift, rotate, blur, horizontal flip, downscale and use gauss noise. I get around 400 images after doing this. Is there anything you would suggest?
I have an accuracy of 98.50 and I have dice of around 0.30-0.65 in each image

And yes, the images are grayscale and they are cropped around the teeth area, so only that part of the X-ray remains.