Dr. Robert L. Simon
Replacing a tooth, or even multiple teeth, can be achieved with any of the following treatment options:
A multiple single-tooth implant restoration
An implant fixed partial denture (implant bridge)
A removable partial denture (RPD)
Conventional fixed bridge (FPD)
Missing teeth may be replaced with multiple single-tooth implant restorations or with implant fixed partial dentures (implant bridges). Implant bridges replace the support lost as a result of missing teeth, avoid the need to drill adjacent teeth, and do not requre an implant for every missing tooth. Appropriate space, gum tissue and underlying bone must be availabe to place the dental implants.
Replacing Multiple Teeth
Implants are placed in strategic positions to replace the missing teeth. When the implants are stable and ready for loading, abutments can be attached to the implants that will connect the final bridge (prosthesis) to the implants. An impression is made, recording the contours of the abutments or the position of the implant tops. The implant bridge is then fabricated and retained in place using the cement screws.
An implant bridge is not susceptible to cavities but may develop complications if oral hygiene is not maintained. This implant restoration should be routinely evaluated- the time interval dependent upon the conditions of the remaining natural teeth and the implant bridge. Restorations using porcelain may be susceptible to a low incidence of porcelain fracture. Patients with large functional forces, including bruxism, may require stronger chewing surfaces.
Replacement with a Conventional Fixed Partial Denture (RPD) or bridges requires reduction of two or more adjacent teeth to make crowns that will be connected to each other with a false (prosthetic) tooth suspended between them. A fixed bridge increases the functional forces placed upon the supporting teeth and complicates the use of floss between the teeth. The number of natural teeth that require reduction is dependent upon the many factors, which include the number and span of missing teeth, the location in the jaw, and the condition of the involved teeth themselves. Convetional bridges may need to be replaced if the supporting teeth develop cavities or periodontal disease.
Implant-assisted Removable Partial Dentures (IRPD) Implant-assisted removable partial dentures utilize a few select implants placed in strategic positions and connected to the overlying denture by means of some sort of stud chewed into the implant. These key implants may eliminate unsightly clasps, reduce the display of metal parts on the denture, and will increase the amount of stability and retention to the final restoration.
This implant restoration should be routinely evaluated at time intervals that are depended upon the conditions of the remaining natural teeth and the IRPD. The denture teeth and retentive elements will be subject to wear and will need to be replaced when necessary. Denture teeth will generally last for years but most retentive elements need to be replaced on a six-month or longer basis.
Replacement with a conventional Removable Partial Denture (RPD) is indicated for patients who can accept having a restoration that is NOT permanently fastened. This restoration should be removed on a daily basis by the patient for oral hygiene access to the remaining natural teeth and the prosthesis. The RPD is made of a metal framework, denture teeth and acrylic. Some patients may not like the appearance of the clasps (metal arms) that engage the remaining teeth to retain the prosthesis, the display of portions of the metal framework, the denture teeth and acrylic. Replacement of worn denture teeth, as well as relining the prosthesis to maintain proper adaptation to the gums, is necessary over time.
The major advantages of an RPD are minimal preparations of the adjacent teeth (significantly less than a bridge), replacement of missing teeth, cosmetic replacement of the lost volume of gum and bone, reduced expense and easier access for oral hygiene. With an appropriate design, an RPD may be modified to add any teeth that may require removal in the future.
What are the primary differences between FIXED partial dentures and REMOVABLE partial dentures?
Fixed Partial Dentures
Fixed prothesesis (does not have to be removed)May require bone grafting for implantsMore costly than removableMay be difficult to clean under bridgeworkProvides some support to facial form
Removable Partial Dentures
Removable prosthesis (must be removed daily)May help avoid bone graftingGenerally more cost effective than fixedGenerally easier to clean because they are removableCan create speech impedimentsCan provide excellent support to facial form