* Even though it is cemented in your mouth, it still is possible for it to become loose at some future time.
    * Once the teeth on either side are ground down for crowns, you are committed to maintaining those teeth for the rest of your life. If there is later a problem with any of those teeth, you will need a complete new bridge. 
Advantages of Dental Implants Over Dentures or a Bridge
Reduced bone loss
Normally, the bone tissue surrounding the root of your tooth is maintained by your body’s natural renewal process. However, if you loose a tooth, you will be left with a hole where your tooth root used to be and the bone around this area will slowly begin to disappear (atrophy) which may change the shape of your jaw. A dental implant placed in that area can actually stimulate bone growth and production, preventing loss of valuable bone structure. In some patients where bone loss is substantial, a bone graft may be required before placing a dental implant. Bone loss is a problem for people who have dentures, and as the shape of the jaw slowly changes, the dentures need to be adjusted or re-made to fit the new shape of the jaw. Bone loss can also make a person look older, since the area around the mouth can sag as bone is lost
Improved function
Once dental implants are fully integrated into your jaw, they function just as well as your own natural teeth: you can eat the foods you want and speak with complete confidence. With dentures, eating hard foods such as an apple can be a problem: either the dentures come loose or patients cannot withstand the hard biting forces as they cause pain in the gums. Irritation and inflammation of the gums is a common problem amongst denture patients. Dentures can be supported by implants or mini-implants, which will greatly improve function, enabling patients to eat the foods they want with complete confidence and not having to worry about bone loss and loose dentures falling out.
Improved dental hygiene
Unlike bridges and dentures, which require special cleaning instructions and extra attention, dental implants just need regular brushing, flossing and dental hygiene appointments, just like your natural teeth.
No need to drill or remove any healthy tooth structure
When replacing missing teeth with dental bridges, the teeth adjacent to the gap need to be prepared and healthy tooth structure is removed to accommodate a crown or bridge abutment to fit over the top of the tooth. In the future, if one of the supporting teeth is damaged, the entire bridge restoration will also be compromised, whereas with an implant, the restoration is independent of any of your other teeth. By replacing lost teeth with an implant, no support is required of the adjacent teeth, and your natural teeth do not need to be prepared or altered in any way
Better aesthetics
If done correctly, a dental implant should be indistinguishable from your surrounding natural teeth. Dentures can come loose and look unnatural if they do not blend with your gums, and some bridges and dentures have unsightly metal clasps to hold them in place. Dental implants provide a much better cosmetic and functional end result.
Replace one teeth