Risk of implant surgery to replace upper molar?

Upper molars are very often replaced with implants . It is considered the ideal treatment in most cases. Sometimes a sinus lift is necessary. It is a very common procedure with very predictable results. The risk is different from a lower molar implant. There is really no other way to restore  a second molar on the upper unless you decide to go without a tooth.

now a days implant and sinus surgery is very common. in yr case , i feel u do not have proper bone, so u have to pay for implant placement  and sinus surgery, so it will cost more. yes, i agree , in many cases upper molar region is costly. if u want to save money , u can avail 'dental tourism'. its very common for implants. almost 80% saving on treatment cost.

In the hands of a skilled surgeon, a sinus lift and implant can have very good success, and It is not uncommon to need a sinus lift if there is not enough bone.  This would be my treatment of choice

Not all upper molar implant replacements require sinus lifts. Sometimes you can get away with a shorter but wider implant. Also, anyone who tells you that sinus lifts are complicated probably does not do so many of them. This is a rather straightforward procedure but needs to be done by a specialist like a periodontist or oral surgeon. Please consult with one of those two specialists in your area first prior to making a decision. 

upper molars are routinely replaced with implants, quite uneventfully.  However, if you lost that molar a few years ago and the sinus is in close proximity, then a sinus lift is often needed to restore adequate bone.  Sinus lifts have become quite routine and very predictable in the right hands and are reliable, but it is an additional procedure.