Which is more effective in treating telangectasia : ndyag or pulsed dye laser... and which is more safe?

Either: Both can be used to treat blood vessels in the skin. Depending on skin tone, pulsed dye may be a better choice because ndyag can sometimes affect pigmentation. Consult a laser specialist and consider a test treatment before treating a large area.

NdYag: I believe NdYag is more effective for vascular lesions such as telangiectasias, but it can be painful unless you have a very short wave length. NdYag is also used to remove pigment, so that is not a consideration in my opinion. You will however have some temporary bruising, caused by disruption of the vessels and leaking. The laser can be used again to treat the bruising if it is bothersome.