There are many different dentists, periodontist, endodontists, prosthetic dentists and oral and maxillofacial surgeons who insert implants.

Restorative Dentist - He specializes in removing dental decay and filling cavities. There are a number of different materials that he can use to fill the cavities.

Oral Surgeon: He is basically a surgeon who does surgeries of the dental and facial structures including the jaw bones. He can extract teeth, remove the wisdom teeth that are deep inside the jaw, perform surgeries of the jaws and face to make them look nice or to treat diseases affecting them. The knowledge of the anatomy of the bone is key to the success of the implant. Within the bone there are anatomical structures that can be injured and knowledge of these structures is key to the overall success.
Also, oral surgeons are not involved in restoration of anything. (This is probably a terminology issue) At best they place implants which are latter restored by a prosthodontist, or they may do a graft of bone (this may be thought of by some as a restoration), but in the strictest sense even that is later restored by someone else. Restorative issues are not their domain, and they are not trained in restoration.

Periodontist - A periodontist is a dental specialist who looks after the gums and helps you maintain good oral hygiene. He can also undertake specialized surgeries of the gums and structures around the teeth.

Prosthodontist - The part of dentistry pertaining to the restoration and maintenance of oral function, comfort, appearance, and health of the patient by the replacement of missing teeth and contiguous tissues with artificial substitutes. Prosthodontics has three main branches: removable prosthodontics, fixed prosthodontics, and maxillofacial prosthetics.

Maxillofacial prosthetics is a sub-specialty of prosthodontics. Maxillofacial prosthodontists treat patients who have acquired and congenital defects of the head and neck (maxillofacial) region due to surgery, trauma, and/or birth defect.

Endodontist - An endodontist specializes in root canal treatment. Dental decay that is neglected often spreads deep inside the tooth and reaches the pulp tissue in the core of the tooth. The endodontist specializes in removing infected and inflamed pulp and filling the area left after its removal.

Orthodontist - An Orthodontist is a dental specialist who specializes in treating crooked teeth by using braces of different types. He also supervises the growing jaw bones and developing dentition and tries to prevent or intercept abnormalities of the bite. Thus the orthodontist can be said to be the dentist who can improve your smile.


Implants
An tooth with infection into the jaw may require several proceedures:
I. Removal and preperation for implant:
  Pull tooth - $350
  Bone Graft - $350
   The bone may fill in naturally, but could have blood vessels that would cause bleeding 
   when the hole is drilled for the implant.
  Gun Tissue Graft or or Guided Tissue Augmentation - $350
  
  The Implant can cost $1,500 - $4,000
  It is done in several steps
  1. A hole is drilled and a titanium screw is placed that comes to the surface of the bone.
    The gum (mucosa) is placed over the implant while both heal (4-6 weeks).
    
  2. A titanium post, called the abutment, is screwed into the implant.
  3. A crown is placed on the abutment.
Cost of Dental Implants - Healthcare Expenses - CostHelper.com
Dental implants - Wikipedia

Links:
Tooth care
Cosmetic Dentistry (straightening, whitening, ...)
Bone Gum Tissue Grafting
Implants at www.cosmeticdentistryguide.co.uk
American Dental Association Web site
Dentistry: Oral Surgeon vs. Peridontist, gum specialist, implant insertion at en.allexperts.com/q/Dentistry-966
32teethonline.com