Change in dominant side of chewing tied to early deterioration of dental implants

Every year, around 2 mln dental implants with fixed dentures attached to them are installed all over the world. An implant is an effective way to restore a deformed or lost tooth without negatively affecting a patient's quality of life. Modern-day dental implants, usually made of titanium, are durable and quick to take in the bone tissue of a jaw. The only issue with them is their early deterioration in 4-5% of patients. Such deterioration is caused by microdamage that occurs when the load on the implant is calculated incorrectly before the surgery. Excessive load affects the junction between the metal and the bone, letting the bacteria in under the implant and causing inflammation. A team of dentists from RUDN University suggested that additional load on the implant might occur when a patient changes the dominant side of chewing in the first months after the surgery.

Most people don't chew symmetrically on both sides of the jaw but have a dominant side that accounts for up to 75% of chewing movements. However, such a side can be changed, for example, because of a sore tooth. It usually takes a patient 3 to 4 months to get accustomed to a dental implant and during this time the type of chewing and the load on the teeth can change. As a result, after the surgery, a patient can switch to a different side of chewing, and load calculations from before the surgery can become invalid. Until recently, the effect of this dramatic change in chewing habits on the state of dential implants remained understudied.

The team monitored the course of rehabilitation of 64 patients with dental implants. The participants of the study were adults with implants installed only on one side of the jaw. Surgeries on both sides of the jaw were not included in the study as they would not allow for measuring the effect of dominant chewing side change. The team took X-ray images of the participants' teeth, measured the strength of their chewing muscles, and in some cases took CT images of the jaws. All these operations were conducted once before the surgery and twice within a year after it. To analyze the results of the treatment, the team asked the participants to fill in questionnaires.

40 patients (62.5%) reported changes in the dominant side of chewing after the surgery. According to the dentists, this might have happened because the patients returned to the chewing patterns they had been used to earlier, before losing a tooth. Having compared this group with the rest of the patients that reported no changes in their chewing habits, the team found out that a change of the dominant side of chewing leads to more bone tissue formation pathologies. In 4 patients with changed chewing habits, the first signs of issue deterioration around the implant were visible in X-ray images. As for the second group, these signs were identified in only one participant. Six months after the surgery the patients that changed their dominant side of chewing felt 22% less adapted to the implants than the patients with no changes in their chewing patterns.

"A change in the dominant side of chewing is an important factor in one's adaptation to dental implants. According to our study, it can also be the reason for pathological processes, eventually leading to the loss of an implant. Dentists need to be aware of the prevalence of such changes, consider them when developing postsurgical rehabilitation plants, and look for their signs during regular checkups," said Prof. Igor Voronov, MD, from the Department of Orthopedic Dentistry, RUDN University.