There are many (about 175) manufacturers of dental implants.
The good thing is that most of the implants available nowadays are of good quality. That being said, some are much better than others though.
Implants vary in many respects. Most root form implants are shaped like screws. Some are tapered and some are straight. Some are long and skinny and some are short and fat. Every situation and every tooth is unique. One size does not fit all.
Certain dental implants have aggressive large threads, while others have micro threads or none at all!
Far more important than the implant itself, is the skill and experience of your implant dentist.
Some implants have surface coatings and others have been acid-etched to create a micro-roughened surface. These help the implants "take" to the bone.
Most older implant systems use an “external hex.”
Some dentists still use these out-dated implants. The problem with an external hex is the abutment screw is more likely to become loose after the crown is already on the implant! For some, the loose screws can turn into broken screws which can become difficult to remove. As an implant dentist in Burbank, I am often referred the toughest cases around.
Most newer implants use an “internal connection” at the implant-abutment
junction. You will likely never have a loose screw with an internal connection implant. It can happen, but it is not nearly as common anymore. Internal hexes and Morse taper cold weld connections are more in favor today.
Besides a lack of screw loosening, the junction of the two parts is tighter which may prevent bone loss and bacterial leakage for years to come after your implants are in.
Some implants have no connection. They are one piece implants so they are just a solid piece of titanium without an abutment screw.
I use tapered, internal connection or one-piece implants for my patients. They have a high success rate and are superior to straight wall, external systems.