In the realm of restorative dentistry, dental implants are king. A dental implant can replace a tooth with a permanent, life-like restoration with a solid reputation for durability.
Implants are also known for one other quality — variety. Not all implants are alike, and they have varied applications for use. Available in various shapes and sizes, they can be used for a single tooth or as part of a multiple tooth bridge or overdenture. Choosing the safest and most durable parts for your dental implant is an essential step in creating long-lasting results you can love.
Implants have many benefits with the main one being that they are a permanent fixture in the mouth and if cared for properly, have the potential to last for the life of the patient. The implant replaces the missing tooth root and stimulates the gum, thus preserving the jaw structure. The completed restoration look incredibly natural and functions in the same way as a natural tooth. It’s also easy to maintain with little more than brushing and flossing and regular dental check-ups.
Dental implants have been used for decades as a permanent, natural-looking alternative to dentures and bridges. Many patients are interested in implant surgery but first want to learn more about the process and the parts that work together to make the procedure a success.
If you’re wondering what the components of a dental implant are, this article will help. This guide discusses the three main parts of a dental implant and how they all work to create a smile that will last for a lifetime.
A dental implant consists of three separate parts: the body, the abutment, and the porcelain crown. The body is made from titanium, the same sort of expensive material that racing cars are made from. It’s used for a dental implant because it’s light in weight and extremely durable, and also it’s biocompatible, which means that it’s very rarely rejected by the human body. So let’s take a look at each component and its role in the dental implant procedure.
The body of the implant is placed into the area of the gum where the tooth is missing during a short surgical process. It’s often cylindrical in shape and resembles a screw. A small incision is made into the gum and a hole is drilled into the bone in which to place the implant body. The gums are then stitched up and the implant left to heal. During this period the surrounding bone will grow over the implant and fuse with it to create a sturdy platform which can support a prosthetic tooth.
Once the implant has fully stabilised and fused with the surrounding bone, then the gum will be opened up again and the abutment will be screwed or cemented into place. This acts as a connector to attach the prosthetic crown to the implant post or body. A false crown will be attached to the abutment to aid the healing process.
Once the abutment has healed then the permanent dental crown will be fitted and your restoration is complete. Depending on the individual the entire procedure can take anywhere from 6 to 9 months and in some cases, over a year, so it is not a quick fix solution to missing teeth.
When selecting the best type of crown to use with a custom abutment, there are several criteria to consider. Anticipated load, esthetic and biologic requirements, implant angulation, and lastly, depth and the occlusal space must all be planned for. Clinicians must also consider any need for retrievability and their own skills and comfort level.
Custom abutments can be made from titanium, gold-shaded titanium, zirconia, or may have a titanium base with a zirconium superstructure. Alumina abutments are still used but have been largely replaced by zirconia abutments. Titanium abutments are often highly suitable for posterior cases whereas shaded zirconia abutments are ideal for anterior cases and can help to eliminate any problems with graying around the gingival area.
Choices for single-unit crowns include porcelain fused to metal (PFMs), layered and full contour zirconia, e.max, and full gold crowns. Clinicians must also decide whether to use a cement or screw-retained crown. Zirconia or cast alloy screw-retained crowns can be predictably retrieved and the risk of retained cement is eliminated. However, the use of modern connection designs generally means crown retrieval is not normally necessary. Additionally, it is possible to make a slight mark on a cement-retained crown to indicate where the screw is located, in case the crown does need to be drilled for access.
PFMs and full gold crowns are both strong and reliable. Because their strength is not derived from cement, even temporary cement can be used to aid retrievability of the crown. If the anticipated load is high, PFM crowns can be fabricated with metal “stops” in the occlusal surface. However, the gingival margins of PFMs may not be the most aesthetically pleasing, particularly when these crowns are used within the smile line.
These lithium disilicate crowns can be extremely strong and may have a strength similar to layered zirconia crowns but ensuring no cement remains subgingivally can be challenging. This is a particularly challenging case when resin cement is used, as the low viscosity and translucency of the cement can make it difficult to thoroughly remove around the gingival margins. Ideally, resin cement should not be used unless additional strength is needed and it is important to note that this type of cement is not suitable when the margin is more than 1.2mm subgingivally. Care needs to be taken when placing an e.max crown over a custom zirconia abutment as high translucency ingots could result in problems with graying. More aesthetically pleasing results may be obtained by choosing a lower translucency ingot and layering the e.max crown to create a restoration with a more natural “liveliness.”
Full-contour zirconia crowns can provide good results and are both strong and durable but very little is known about the long-term effects on enamel. Layered zirconia crowns tend to be more suitable in areas where there is plenty of occlusal clearance and can provide better esthetic results, depending on the skill levels of the technician responsible for layering the porcelain. Both layered and full-contour zirconia crowns can be cemented to the abutment using almost any type of cement on the market.
Clinicians should choose the most appropriate crown based on each patient’s individual needs, as one choice will not suit every patient. The choices available should generally provide good results and ultimately, crown selection may also come down to personal preference.
And while dental implant basic architecture is the same, you also have two options for how the permanent crown (the visible tooth portion) attaches to the implant: screwed or cemented.
The condition of your mouth, the type of implant you’re receiving and other circumstances will all factor into determining which method is best for you. If dentists are “immediately loading” the crown (meaning they are affixing a temporary crown to the implant immediately after placement in the jaw), then the screw method may be more advantageous. Aesthetically speaking, though, a cemented crown may be a better option in terms of final smile appearance.
But whichever method is used, you’ll still benefit from what implants do best — help you regain the function lost from a missing tooth and change your smile for the better.
Cemented crowns require a two-piece assembly, in which an abutment is attached to the implant with a screw. Following this, the implant crown is cemented onto the abutment.
This option is natural in appearance, has no screw access hole, and offers superior cosmetic flexibility to screw-retained crowns. In rare instances, inflammation of surrounding soft tissue can occur as a reaction to the cement. Additionally, there are limited removal options available.
Screw-retained crowns are attached directly to the implant with a screw. These crowns have the abutment and the crown itself fused in one single component, therefore not requiring an abutment, nor cement.
Post-procedure, they allow ease-of-access to the screw which allows for more efficient repair should issues arise. The implant access hole, while enabling quick fixes to minor issues such as loosening of the crown, can pose a risk of chipping to the porcelain crown. It’s also worth considering the inferior cosmetic appearance of screw-retained crowns.
As to which retention method is most suitable, it differs per each patient’s individual requirements as determined by the implantologist.
Accessibility is another concern. Restoring a screw-retained restoration in a patient with a limited opening and/or in the posterior of the mouth can be challenging. The implant abutment connection must line up with the interproximal contacts to allow seating of the one-piece restoration. A cement-retained crown may be easier to deliver in these situations.
Cost may be a factor to consider as well. The cemented implant crown costs considerably less because of lower laboratory fees and fewer components. Fewer and shorter appointments are needed to restore a cement-retained crown, which is more cost effective for the prosthetic dentist. Temporary crowns with cementable implants are far easier to fabricate than screw-retained provisionals.