10: Implant Dentistry: Substitutes for Tooth Roots Placed into Your Jaw

CHAPTER 10 Implant Dentistry

Substitutes for Tooth Roots Placed into Your Jaw

Dental practitioners have tried to develop artificial teeth to be placed in the jawbones since the origin of dentistry, but in recent years activity has increased in the area of implant dentistry. Initiated by Swedish research in the 1960s, the placement of small titanium cylinders or screws into the jawbone has progressed from an experimental (and highly criticized) procedure to common usage by many dentists (Fig. 10.1). The titanium-screw concept popularized implant use, but other types of implants were available much earlier. Examples are blades placed into the jawbone, with heads protruding above the gums (Fig. 10.2), and subperiosteal implants placed on top of the bone, between the bone and gums (Fig. 10.3). These types of implants are still used, but the screws or cylinders are more popular.

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FIG. 10.1 Titanium screw-type implant goes into the jawbone, and the collar connects implant to artificial teeth held by screw.

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FIG. 10.2 Blade implanted in jawbone 10 years earlier.

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FIG. 10.3 Subperiosteal implant in lower jaw, performed 12 years earlier.

Do these tooth substitutes (dental implants) work? Yes, in the mouths of healthy people, without abusive oral habits or excessive smoking. Their ability to function rivals that of natural teeth. In severe cases they have allowed persons unable to wear conventional artificial dentures to chew well and appear normal. The most popular current concept (cylinders and screws) requires one or two clinical sessions.

1. The gum tissue is opened, and the screwlike titanium implant is placed into the bone (Fig. 10.4). This implant combines with the bone as the bone cells grow into its surface. This process, which has been called osseointegration, takes several months. During this time, the implant is usually sealed below the gum, away from mouth fluids and debris, while it heals into place.
2. On the second appointment, a small hole is made in the gum tissue, and the implant is exposed. A healing cap is placed on the implant for a short time, and a head is placed onto the implant body (Fig. 10.5). The gum tissue heals for a short time, and the dentist places some artificial teeth (prosthesis) onto the implant(s) (Fig. 10.6). These artificial teeth can be made to appear and function as well as or better than natural teeth.
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FIG. 10.4 One screw-type implant, shown with three different lengths of healing caps.

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FIG. 10.5 One screw-type implant, shown with three different types of abutment heads.

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FIG. 10.6 Schematic drawing of implant and abutment head (green) and crown (cap) screwed into implant. Yellow is bone; red represents gums.

On occasion, only one appointment is required. The implant is placed and allowed to protrude into the mouth. It may be restored on that appointment or at a later time.

Not all dentists provide implants. There are two distinct divisions in the implant procedure described. The placement of the implant into bone is a surgical procedure performed by oral and maxillofacial surgeons, periodontists, prosthodontists, and some general dentists. If your general dentist does not provide this service, he or she will refer you to a practitioner who performs the surgical portion of the procedure. Both portions of the implant procedure are exacting techniques requiring high skill, and experienced practitioners must be found for an optimal result. Prosthodontists or general dentists usually accomplish the second portion, or attachment of the artificial teeth (prosthesis) onto the implant(s).

If implants are so good, why doesn’t everybody have them instead of natural teeth? Numerous aspects of the implant concept are complicated and difficult for dentists placing them, making the procedure less predictable than desired. Implants are expensive, and, as with natural teeth, require upkeep by patients and dentists. When implants are really needed, they do not have satisfactory substitutes. The task for you and your dentist is to determine whether your oral needs would be served best by using dental implants to replace the root structure of the natural teeth, followed by some form of prosthesis (artificial replacement) for the missing tooth structures. The following pages will help you make that decision with the help of your dentist.

WHAT YOU SEE OR FEEL

Conditions, Signs, Symptoms Related to Implant Dentistry

1. All of Your Natural Teeth Have Been Removed

(Fig. 10.7). This type of condition is called edentulous. Loss of all teeth is decreasing in frequency because of the use of fluoride, better diet, and improved oral hygiene. However, millions of people around the world have lost all their teeth. Unfortunately, much of this tooth loss is among those persons who are least able to afford having implants placed.

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FIG. 10.7 Facial collapse in edentulous person (no teeth present).

Persons without any natural teeth have several classic signs and symptoms, some of which can be helped significantly by the use of implants and tooth replacements.

A. Collapse of Facial Form: Edentulous persons have reduced underlying support for the muscles of the face below the nose. These muscles collapse into the void space of the mouth, giving the person an aged appearance (Fig. 10.8). In edentulous persons the lower jaw can close much farther than normal before it stops and hits any structures. Some edentulous persons cannot touch their upper and lower jaws together after the teeth have been removed. Few people want to have a collapsed facial appearance.
B. Bone Shrinkage: When teeth are removed, the bone previously holding the teeth shrinks at a fast rate, leaving only a small percentage of the supporting bone present after many years of having no teeth (Fig. 10.9). In the later years of life, the amount of bone remaining in the jaws may be only one third or less than that of normal bone structure. The jawbones are weak and cannot support artificial dentures well.
C. Reduced Eating Efficiency: Most conventional artificial removable dentures perform well for several years after tooth extraction before a significant amount of bone shrinkage has taken place. However, almost all edentulous persons eventually reach a point where the lower and sometimes upper dentures allow only a fraction of the chewing effectiveness of natural teeth. Without adequate artificial dentures, edentulous persons must eat only soft or liquid foods.
D. Inability to Hold Traditional Dentures in Place: As unavoidable bone degeneration takes place in the edentulous person, conventional dentures are difficult to keep in place in the mouth. This condition often reduces self-esteem and stimulates overall dissatisfaction with the oral part of the body.
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FIG. 10.8 Severe facial collapse and thinning of lips in edentulous person. This face can be made normal again with prosthodontics (dentures).

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FIG. 10.9 A, Lower jaw after tooth removal and healing. B, Jaw after 15 years of shrinkage.

If you are an edentulous person, you have the following alternatives:

(1) Reline or Rebase Your Old Dentures (p. 161). If your dentures are satisfactory except for fit, relining or rebasing your old dentures may be accomplished.
(2) Place Conventional Complete Dentures. Obtain conventional complete dentures without any surgical changes in your mouth (p. 163).
(3) Change Soft Tissues in Mouth Surgically. You may have the soft tissues in your mouth changed surgically (p. 97), providing more bone support for a new denture; then obtain new conventional dentures.
(4) Place Implants and Construct a Removable Denture. Place implants, allow healing, and obtain a removable denture that is supported and retained by the implants. You can remove this prosthesis each day for cleaning (p. 66).
(5) Place Implants and Construct a Fixed Denture. Place implants and construct a fixed denture that is supported and retained by the implants. You cannot remove this prosthesis yourself. Some of these prostheses are removable by the dentist only, and some are cemented into place and are not removable at all unless required by breakage (p. 69).
(6) Do Nothing. If you elect to do nothing, the signs and symptoms will continue to get worse until you are forced to do something.

2. Some of Your Natural Teeth Have Been Removed

(Fig. 10.10). A high percentage of people lose some of their natural teeth during their lifetime because of accidents, tooth decay, gum and bone disease, or other reasons. Although there are numerous solutions for replacing several teeth, dental implants are an excellent alternative.

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FIG. 10.10 Note enormous bone and gum shrinkage where teeth have been missing for 5 years. An implant has been placed in the area of missing teeth for a future prosthesis (bridge).

• Collapse of Facial Form: Although not as severe as the facial changes caused by loss of all teeth, losing a few teeth also produces a sunken facial appearance. Teeth adjacent to the space move into peculiar positions. The appearance of a smile with a few missing teeth is considered unacceptable by most people (Fig. 10.11).
• Bone Shrinkage: When a few teeth are removed, the supporting bone shrinks from then on, leav/>

Related posts:

  1. 11: Occlusion: Your Bite, Temporomandibular Joints, Temporomandibular Dysfunction
  2. 20: Additional Sources of Information
  3. 7: Endodontics: Root Canals, Dead Teeth, Inside of Teeth
  4. 18: Restorative or Operative Dentistry: Fillings for Teeth
  5. 12: Oral and Maxillofacial Surgery, Oral Pathology, Oral Medicine: Diseases and Surgery Related to the Oral and Facial Areas
  6. 17: Prosthodontics, Removable: Dentures Replacing All or Some Teeth

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Jan 3, 2015 | Posted by in General Dentistry | Comments Off on 10: Implant Dentistry: Substitutes for Tooth Roots Placed into Your Jaw

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