Implants

A dental implant is an artificial tooth root used in dentistry to support restorations that resemble a tooth or group of teeth. In its most basic form the placement of an osseointegrated implant requires a preparation into the bone using either hand osteotomes or precision drills with highly regulated speed^[15] to prevent burning or pressure necrosis of the bone. After a variable amount of time to allow the bone to grow on to the surface of the implant (osseointegration) a tooth or teeth can be placed on the implant. The amount of time required to place an implant will vary depending on the experience of the practitioner, the quality and quantity of the bone and the difficulty of the individual situation²⁸

A Straumann-brand root-form endosseous dental implant placed in the site of the maxillary left permanent first molar with bone graft used to elevate the sinus floor.

Abutments

In dentistry, an abutment is a connecting element used to attach prosthetics to a dental implant that is Osseointegrated. These are usually called prosthetic implant abutments. These abutments can be made from a variety of materials, such as titanium, surgical stainless steel and gold. More modern abutments are now also made from zirconia, which is a white ceramic, to better complement the aesthetics of a dental implant restoration. The two images to the right show a ceramic abutment and the ceramic crown bonded to it.²⁹

Ceramic Abutment connected to implant

Crown

When preparing a tooth for a traditional crown, the enamel may be totally removed and the finished preparation should, thus, exist primarily in dentin. Where the traditional indirectly fabricated crown requires a tremendous amount of surface area to retain the normal crown, potentially resulting in the loss of healthy, natural tooth structure for this purpose, the all-porcelain CAD/CAM crown can be predictably used with significantly less surface area.  As long as the thickness of porcelain on the top, chewing portion of the crown is 1.5mm thick or greater, the restoration can be expected to be successful.  Traditionally, all-ceramic restorations have been made off site in a dental laboratory either out of feldspathic porcelains or pressed ceramics. This indirect method of fabrication involves molds and temporaries, but can yield quite beautiful end-results if communication between the laboratory and the dentist is sound.

Although no dental restoration lasts forever, the average lifespan of a crown is around 10 years.³⁰

Bridge

When restoring an edentulous area with a bridge, the bridge is almost always restoring more teeth than there are root structures to support. For instance, in the photo at right, the 5-unit bridge will only be supported on three abutment teeth. To determine whether or not the abutment teeth can support a bridge without failure from lack of support from remaining root structures, the dentist employs Ante's rule—which states that the roots of abutment teeth must have a combined surface area in three dimensions that is more than that of the missing root structures of the teeth replaced with a bridge. When the situation yields a poor prognosis for proper support, double abutments may be required to properly conform to Ante's rule.³¹

A semi-precision attachment between teeth #3 and #4, with the female on #4. Note the lingual buttons extending, in the photo, upward on #2 (on the left) and downward on #4. These are used to grasp the crowns with a hemostat and make them easier to handle. They can also be used to aid in removal of the crown in case there is an excessive amount of retention during the try-in. They are cut off prior to final cementation

Upper and Lower Plates

Complete dentures or full dentures (upper & lower plates) are worn by patients who are missing all of the teeth in a single arch (i.e the maxillary (upper) or mandibular (lower) arch).  Another problem with dentures is keeping them in place. There are three rules governing the existence of removable oral appliances: support, stability and retention.³²