*Replacing a single tooth* It can be achieved with a conventional bridge or an implant retained crown.The conventional fixed partial denture (fixed bridge) requires that your dentist drills down two or more adjacent teeth to create space for the crowns of the prosthetic teeth. Placing a bridge on natural teeth increases the functional forces that are placed upon them and makes the use of floss between the teeth more difficult. Conventional bridges may need to be replaced if the supporting teeth develop cavities or periodontal disease. In a certain percentage of instances while preparing the adjacent teeth for crowns (i.e. drilling down a tooth), the preparatory procedure will cause the nerve of the tooth to die and require root canal treatment to eliminate infection of the nerve.
An implant single-tooth restoration avoids the need to restore the adjacent teeth and also replaces the support that is lost with the missing tooth. This allows normal flossing as if the replacement implant were a natural tooth. An implant is placed in the position of the missing tooth. When the implant is stable and ready for loading, an abutment can be attached to the implant that will connect the final crown to the implant. An impression is made to record the contours of the abutment or the position of the implant top. The crown is then fabricated and fixed in place using cement or screws. An implant crown is not susceptible to cavities but may develop complications if oral hygiene is not maintained. The implant restoration should be routinely evaluated in time intervals that are determined by the conditions of the remaining natural teeth and the implant.
*Replacing multiple teeth*
Replacing multiple teeth can be achieved with a multiple single-tooth implant restoration, with implant fixed partial dentures (implant bridges), with a removable partial denture (RPD), or with a conventional fixed partial denture (FPD). The missing teeth may be replaced with multiple single-tooth implant restorations (described under replacing single teeth), 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 the adjacent teeth and do not require an implant for every missing tooth. The space, gum tissue and underlying bone must be appropriate to place the dental implants.
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 cement or 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 metal chewing surfaces.
Implant-assisted removable partial dentures (IRPD) utilize a few select implants placed in strategic positions and connected to the overlying denture by means of some sort of stud screwed into the implant. These key implants may eliminate unsightly clasps, reduce the display of metal parts on the RPD, and will increase the amount of support, stability and retention to the final restoration.
With an appropriate design, an IRPD may be modified to add any teeth that may require removal in the future. When the implants are stable and ready for loading, abutments can be attached to the implants. The abutments may be used individually as stud attachments or as part of a larger, laboratory manufactured super-structure with various types of clip-type attachments (or retentive elements) which engage the RPD. An impression of the teeth and retentive elements is made so the laboratory can fabricate the final prosthesis. The retentive elements may be processed in the laboratory or in a clinical procedure that is performed chair-side. This implant restoration should be routinely evaluated at time intervals that are dependent upon the conditions of the remaining natural teeth and the implant RPD. 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 up 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 usually 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.
Replacement with a conventional fixed partial denture (FPD) or bridge 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 many factors which include the number and span of the missing teeth, the location in the jaw, and the condition of the involved teeth themselves. Conventional bridges may need to be replaced if the supporting teeth develop cavities or periodontal disease.
*Replacing all teeth in jaw* If you are missing, or need to remove all teeth in one or both jaws, implants may allow you to have a fixed full-arch bridge fabricated as well.
As an alternative to wearing a full denture (if there is adequate bone or bone augmentation procedures can be performed to grow sufficient bone) multiple implants can be placed across the jawbone to provide support for a fixed bridge. This procedure is similar to those described for single or multiple implants but requires careful diagnosis, planning and coordination before treatment begins. This attention to detail will ensure that an appropriate number of implants can safely be placed in positions that will allow your dentist to fabricate a bridge which will meet your needs and expectations.
The number of implants necessary for a full-arch fixed bridgevaries depending on your particular anatomy, the opposing teeth, the type of bridge you want to have placed and the number of teeth you want or need to replace with the prosthesis. A full arch of implants can be placed when you are already missing all teeth in one of your jaws. If you have teeth remaining, they may need to be removed as a first step before implant surgery can proceed, or sometimes the teeth may be extracted and implants placed immediately after the teeth have been removed. If there are teeth remaining, you may be able to have a temporary fixed-bridge made by your dentist to help transition from your own teeth to implants. In this scenario (while the implants are healing), the temporary bridge stays in place which allows chewing, speaking and smiling - all without having to wear a removable denture. If it is not possible to retain enough teeth to support a fixed bridge while the implants are healing, then you may need to wear a removable denture temporarily.
Usually, you will be advised by your dentist to refrain from wearing the denture for a period of time (customarily two weeks) after the implants have been placed. This allows the gums to heal without being disturbed. In recent years, we have learned that it is often possible to place a full arch of implants and connect them to a fixed bridge (usually temporary) in what is known as immediate loading - which means the implants are receiving "load" from chewing forces as soon as they are placed.
This newer procedure is highly successful but there are certain requirements for its success. This technique requires careful planning and coordination by your dentist and surgeon and as with all treatment, you should discuss all of your options and alternatives with your dentist and decide together which may be the best and most appropriate for you.
what is an implant over denture?
An implant overdenture fits over a dental implant with various types of attachments that provide you with excellent stability and retention of your complete dentures. The implant overdenture is a full denture used to replace the teeth in a full-arch where all the teeth are missing. In essence, it is a larger version of the implant assisted removable partial denture (IRPD). The denture can "snap" into place to afford you more comfort, and improved chewing ability. Implant overdentures are held in place by various dental attachments selected by your restorative doctor to provide maximum retention, and increased chewing ability. The implant overdenture is removable to facilitate cleaning of the implant supporting structure. Implant overdentures can be made to look extremely natural and feel comfortable.
Pre-surgical prosthodontic planning for implant overdenturesbegins with diagnostic impressions for recording jaw relation and diagnosing possible dentures. These impressions help to determine the correct positioning of the teeth on the new dentures as well as to confirm the optimal location for each implant. They are also used to assure correct appearance and bite. Frequently, a template is produced from the diagnostic impression that is provided to the surgeon for guidance during implant placement surgery.
Most often, an upper overdenture will require placement of more implants than a lower overdenture due to the different nature of the anatomy of the upper and lower jaws. It may also be possible to fabricate an upper denture without a palate (roof of the mouth), which may be a more comfortable option for some patients.
The specific need for an implant overdenture can vary and the decision for this treatment option should be made with your restorative dentist. Many patients can benefit from the facial support provided by the extensions of the complete denture design. The number and type of implants should be decided upon following a detailed discussion between you and your dentist(s), a thorough examination, and careful consideration of your personal experiences with your current dentures.