The majority of dental implants are made of titanium alloy. The implant is the screw (functioning as an artificial tooth root) inserted into your jaw. The prosthetic tooth itself is typically ceramic. Titanium alloy is often the default choice for an implant, but full ceramic implants (made of zirconia) are gradually becoming more common. It's important for a patient to know what type of implant has been installed in their jaw, as this allows them to anticipate any potential complications, such as implant failure due to fracture. 

Types of Implant Failure

It's rare for dental implants to fail. When these failures occur, they can be categorized as early, pre-loading failures (before the prosthetic tooth is attached to the implant), or later, post-loading failures (after the tooth is attached). In addition to the timeframe of the issue, failures can be described as biological (such as due to infection of the tissues surrounding the implant, or its integration with your jaw), or mechanical (a fault with the actual implant). While zirconia implants aren't necessarily more susceptible to mechanical failure, the fact that the implant is entirely ceramic can play a role in any failure.

Excessive Pressure

It's not as though dental implants are prone to fracture. However, when an implant is exposed to improper post-loading forces (beyond the capacity of the implant), then there's a small risk of the implant cracking. This isn't a significant issue with zirconia implants, but when titanium alloy and zirconia are exposed to the same degree of excessive pressure, it's reasonable to conclude that an all-ceramic implant may fracture.

Reasons for Implant Fracture

This excessive post-loading pressure can be experienced in a number of ways. The zirconia implant may have been installed in a posterior tooth, such as a molar or premolar, which experience far more bite pressure than an anterior tooth (towards the front of your mouth). This isn't to suggest that zirconia implants are conclusively unsuitable for posterior teeth, but this continual pressure can become destructive when another factor becomes relevant.

Other Contributing Factors

The bite pressure experienced by a tooth may be altered over time. An unrelated dental problem in another tooth may change the configuration of your bite, leading to increased pressure on the zirconia implant. Similarly, patients who begin to grind their teeth (a condition known as bruxism) will apply excessive pressure to natural teeth and dental implants alike.

Getting Assistance

The physical signs of a fractured zirconia implant vary, but generally include discomfort at the implant site, sometimes with a noticeable loosening of the prosthetic tooth. Obviously, the implant is synthetic, so it cannot heal. You must see your dentist. A fractured zirconia implant will be removed. Before a replacement is added, the initial reason for the fracture will be investigated. If this cause can be mitigated, you may be eligible for another zirconia implant, if this is your preference. However, it may be necessary to fit a titanium alloy implant if the cause is likely to affect your zirconia implant again.

Remember that a zirconia implant fracture is unlikely to happen, but it's still important to know how and why it happens, allowing you to quickly rectify the problem.

Contact your dentist if you have more questions about dental implants.