Dental implant treatment is an increasingly popular method for replacing one or more missing teeth. As the US population ages, so does the demand for effective solutions for lost teeth. Permanent and stable replacement options can help people maintain their smiles and can also help people continue to eat their favorite foods, maintaining a long-term, high quality of life. Over the next few years, the number of people with dental implants is projected to continue to increase, largely due to the high success rate of implant dentistry and the increasing popularity of dental implants among the aging. As dental implants have grown more popular, technologies associated with dental implant treatment have also improved and expanded. The increased availability of different dental implant technologies has provided today’s dental implant recipients with a vast and valuable selection of options.
There are currently hundreds of companies that make components for dental implants, though only a few are respected worldwide. These popular, reputable companies include Straumann, Zimmer Biomet, Nobel BioCare, MIS, BioHorizon, and Dentsply. These manufacturers provide reliable components with a long history of positive reviews, and dental laboratory technicians are familiar with their specifics and fluent in their manufacture and use. Dentists who use these more reputable companies may receive specialized training to use these brands, and patients may prefer to seek out dentists who are affiliated with these successful brands. One other benefit of using implants from a reputable and widely known company is that they can be easily maintained, and parts can be readily replaced, no matter where the patient may be in the world. These top manufacturers are on the cutting edge of development, having extensively researched dental implant technologies.
When dental implants are first introduced into the body, there is a risk of rejection as the cells of the body communicate with the materials of the implant. Consistent research innovations improve this communication and lead to a higher likelihood of osseointegration between the implant and the bone, and research data from these reputable manufacturers is widely available to support their reputations. While this evidence is beneficial, a multitude of evidence can complicate the process of selecting which dental implant system is the best for each patient’s specific needs; especially with more complex dental situations, it is imperative for the patient and dentist to work closely together to determine which implant system is best in each case.
The two primary divisions in implant type include implant crowns that are cemented to the implant fixture, and implant crowns that are screwed on. These also include custom abutments and stock-made abutments. Custom abutments are usually preferred for aesthetic reasons, though this also varies from patient to patient and tooth to tooth. Traditionally, dentists have preferred to use titanium implant fixtures, though zirconia is increasing in popularity. Finally, the type and material of crown or prosthesis must be taken into consideration.
There are a few specific factors to think about when deciding whether to use cement-retained crowns or screw-retained crowns. These factors include retrievability, ease of use, suitability for specific implant types, compatibility with the tissues surrounding the implant, and cost. When implant crowns need to be removed, it can be more challenging to remove a cemented crown. While there are cements that are designed to be temporary, these cements can also contribute to lower retention rates for crowns. Screw-retained crowns are often more easily retrieved and may be preferable especially in cases where a number of implant abutments are needed. When crowns are cemented, excess cement can ooze into the gingival sulcus, or the space between the free margin of the gums and the surface of the crown. This can cause damage to the tissues surrounding the implant, increasing the risk of peri-implantitis. There are effective techniques in place to remove excessive cement following the placement of a crown, though screw-retained crowns remove the risks from excessive cement entirely. Screw-retained crowns can also be removed easily, allowing for ready maintenance and cleaning.
Screw-retained crowns may be more challenging to insert than cement-retained options, especially when there are multiple abutments required for the restoration. Placing these restorations effectively takes several extra steps. Sometimes, for aesthetic reasons, it is necessary to place angled implants in the jaw; these angled implants require angled abutments. When angled screw-retained abutments are needed, overall cost can increase dramatically; for this reason, a cement-retained crown on a custom or stock angled abutment may be preferable.
Each implant will also require either a stock abutment or a custom abutment. Stock abutments are more frequently used for cement-retained restorations and are usually a more economical option than custom abutments. Both angled and straight stock abutments are available, though they are mostly preferred for tissue-level or bone-level implants that aren’t readily visible, as stock abutments are standard in size and can affect the shape of the adjacent tissue. Stock abutments also increase the challenges associated with the final placement of the crown related to the gingival margin. Custom abutments can be effective for all placements of restorations, as they can be molded or milled into precise sizes and shapes. Custom abutments are most often made from titanium or zirconium, or from a combination of the two materials. While custom abutments are more expensive than stock abutments, they are preferable for aesthetic reasons and for tissue management, and they may be more cost-effective as they require fewer modifications and clinical resources while being fitted. Custom abutments work well for both screw-retained and cement-retained crowns.
Because titanium integrates well with bone and has an established record of strong biocompatibility, many dentists prefer to use titanium dental implants. While titanium itself is too soft to effectively support dental implants, titanium alloys retain the biocompatibility of titanium while offering far greater strength. Bone grows readily on titanium, increasing the stability of titanium implants after osseointegration. Titanium alloy implants have a high success rate, often exceeding 95%. Though rare, some people may be allergic to some of the materials used in these titanium alloys; others may have concerns about having metals implanted into their bodies. Due to these concerns and possible allergies, some implant manufacturers have researched and developed non-metallic implants made of zirconium. Zirconium is called a ceramic material, though it does contain small amounts of some metals that help increase its strength. Zirconium is very strong, and zirconium implants have been found to integrate with the bone as effectively as titanium.
Titanium has proven to be effective over the long term, as evidenced by successful implants that are decades old. Long-term success rates of zirconium are not yet available. Titanium is a more versatile option, as they can be fabricated in different ways that allow greater flexibility in planning and treatment. Titanium can also be used to support multiple different types of restorations. Zirconium implants are crafted as a single piece, which, in turn, requires that restorations must be cemented into place. Because there is very little room for error with these zirconium implants, bone volume is very important, and these implants must be placed carefully. Zirconium does not corrode, and it is non-conducive, and the ceramic color of zirconium implants can provide aesthetic benefits. For many patients, titanium implants are a reliable and flexible approach that will provide time-tested results. When patients have concerns about using metal for their dental implants, however, zirconium can be an appropriate alternative, with some limitations.
While conventional dental impressions have consistently provided molds and models for dental restorations, in recent years, digital technology has provided new methods for measuring and shaping dental restorations. Intraoral scanners collect digital data that allows extremely precise dental restorations to be made. Many dental laboratories accept these digital dental impression files and can work with the data they provide. Some dental labs use these digital impressions to create resin or polyurethane models that are then used to conventionally fabricate dental restorations. Other labs use this digital impression data to generate graphic designs through a CAD or CAM program. Depending on the material being used to fabricate the crown, the lab may use exclusively digital impression methods, exclusively traditional methods, or a combination of both. While digital scanning technologies may increase the cost of restorations, the reduced cost of impression materials and lab bills should be considered. For some patients, traditional dental impressions can cause discomfort, possibly triggering the gag reflex or causing stress or pain while they are being prepared. For these patients, digital impressions may be particularly preferred. Digital models are highly accurate and may provide more precise clinical measurements than traditional impressions can. Digital impressions may also lead to shorter laboratory times, facilitating accurate manufacture and allowing revisions to be made before manufacture is complete. In many cases, the company that has created the digital impression tool will provide training for their product, either onsite or at the company’s offices.
Thanks to the increased affordability and availability of cone beam CT scanners, many dental practices have chosen to invest in these technologies. Cone beam CT scans can be helpful in planning dental implant restoration treatments, as they provide immediate information about the placement of anatomical features and help clinicians readily determine both the quantity and quantity of alveolar bone. Cone beam CT scans help clinicians identify pathology and determine the need for additional treatment, like bone grafts or sinus lifts. They can also help clinicians perform “virtual surgery,” evaluating the quality of the bone and determining any possible limitations before surgery is even begun. This can be particularly helpful with complicated clinical situations that require zirconium full-arch bridges. These technologies may also help clinicians share 3D models or other digital images of possible outcomes with patients before surgery is even begun.