“Do all dental implants need bone grafts?”

No

No!

The ultimate success of a dental implant relies on several facets... some you can control - such as being a non-smoker (not judging, it's just a fact that up to 50% of implants placed in smokers fail). Other factors you can't control such as bone density - the "hardness" of the bone holding the implant, and bone volume - the amount of bone necessary to successfully keep an implant in your jaw. By nature, the lower jaw has better bone density than the upper jaw. Also by nature, the upper jaw has less bone volume in the back of the jaw than the front of the upper jaw. Dentists NEED good bone volume and bone density to assure a long-lasting implant. We often need to add a bone graft to an upper posterior area of the jaw in order to give the implant the best chance at success. This is primarily due to the presence of your sinuses in the upper skull. So, a procedure is done to add bone to an area of low bone volume and/or density. It is a common procedure nowadays when a tooth is extracted that if we are treatment planning a future implant there, we'll automatically place a bone graft into the extraction site to maximize future bone volume. So, to answer your question directly, not all dental implants require a bone graft, but certain parts of the jaw require a certain volume of bone to ensure a successful implant. If your dentist has recommended a bone graft, you can rest assured that your dentist is wanting your future implant a good chance of success.

It is not always necessary.

Bone grafting is not always required for dental implant placement, but in cases in which this procedure is indicated, it can help to significantly improve the patient's chances of good treatment outcomes. Only your surgeon can determine the need for a bone graft, often with the use of special imaging technology. The younger you are the less likely you need a bone graft. If the tooth you are replacing has been extracted less than 1 year and did not have bone infection, the need for bone grafting decreases.

If there is sufficient bone of good quality present, then a bone graft is not required. If there is not enough bone in height or width, then a graft would probably be necessary.
I hope this answers your question.