Bruxism is defined as “the repetitive jaw muscle activity characterized by the clenching or grinding of teeth and/or by bracing or thrusting of the mandible.” It can occur during sleep or while awake. It has been linked to multiple negative consequences associated with oral health.1
A systematic review and meta-analysis aimed to evaluate the effects of bruxism on implant failure. The focused question was, “In patients rehabilitated with dental implants, what is the effect of bruxism on the implant failure rates and marginal bone loss (MBL)?”1
The Review
The review included human studies that provided data on implant failure rates as the primary outcome in both bruxers and non-bruxers treated with cylindrical modern dental implants made of commercially pure titanium or its alloys. Marginal bone loss (MBL) was evaluated as a secondary outcome. Studies lacking MBL information were not excluded if they provided data on the primary outcomes. Only studies utilizing the long-cone parallel technique for periapical radiographs were considered.1
Studies were included if they detailed the criteria for diagnosing at least probable bruxism (based on self-reports and clinical examination), with or without a control group of non-bruxers. As individuals are classified as either bruxers or non-bruxers, randomizing implant placement for this condition was not feasible. Therefore, non-randomized and retrospective clinical studies were also included.1
The review focused exclusively on cases rehabilitated with cylindrical screw-type modern dental implants made of titanium or its alloys. Exclusion criteria encompassed case reports, technical reports, animal studies, in vitro studies, and review papers. Studies involving mini-implants, orthodontic, zygomatic, zirconia, subperiosteal, or hollow implants were also excluded.1
An implant was deemed a failure if it exhibited signs and symptoms necessitating its removal. Implant failures were categorized as either early, where the host was unable to establish or support osseointegration during the initial healing phase, or late, where there was a breakdown in the established osseointegration or the functional performance of the dental implants. Additionally, implant fractures were classified as failures.1
Out of the 1338 studies identified, after screening and assessment, 27 studies were included with data on 2405 implants in probable bruxers and 10,264 implants in non-bruxers, with 138 and 352 implant failures in respective groups.1
The Results
The main finding of this review is that individuals likely to suffer from bruxism have a significantly higher risk of dental implant failure compared to those who do not. This increased risk is likely related to the potential negative effects of bruxism. Bruxism is often associated with excessive loading of the dentition. For dental implants, this unpredictable and uncontrolled overloading can lead to micromotions beyond the critical threshold, resulting in fibrous encapsulation of the implant and thus compromising osseointegration.1
Additionally, dental implants may be subjected to higher loads than natural teeth due to their limited proprioceptive feedback mechanisms. This is because implants lack periodontal ligaments, which reduces tactile sensitivity. Consequently, this decreased feedback can increase the risk of applying higher forces due to parafunctional oral behaviors, raising the likelihood of implant failure.1
The statistically significant higher failure rate in probable bruxers compared to non-bruxers suggests that dentists should carefully consider the presence of bruxism when planning implant treatment. This may involve choosing specific types of implants (e.g., in terms of length and diameter), determining the number of implants relative to the number of missing teeth, avoiding free-end saddles, splinting implants, and recommending protective splints post-implant therapy.1
Although this cause-effect relationship requires further confirmation through well-designed studies, the current evidence supports these recommendations. The use of oral appliances may be prudent despite the lack of definitive literature evidence regarding their impact on implant survival.1
None of the included studies reported results on MBL separated by bruxers and non-bruxers. However, the first clinical study comparing MBL between probable bruxers and a matched group of non-bruxers suggests that bruxism increases the risk of MBL over time. Therefore, it can be assumed that probable bruxers may exhibit greater MBL around implants than non-bruxers. This could be because natural teeth have a lower detection threshold for minimal pressure compared to implants, leading to more even stress distribution around natural teeth, whereas stress around implants tends to concentrate at the crestal bone region.1
The findings of this review should be interpreted with caution due to its limitations. Firstly, various confounding factors could have influenced the long-term outcomes, not solely the distinction between implants placed in probable bruxers versus non-bruxers. The studies included in this review exhibit a significant number of confounding variables. Additionally, most of these studies did not provide detailed information on the number of implants placed and their survival or failure rates under different conditions.1
Conclusion
The clinical takeaway from this review is the recommendation to assess for bruxism during the planning stage of implant treatment. This aligns with prior advice to exercise caution when placing implants in patients who exhibit bruxing behaviors.1
Although studies directly comparing MBL between these groups are still lacking, the overall evidence from this systematic review indicates that implants in probable bruxers have a significantly higher risk of failure compared to those in non-bruxers. This should be a key consideration in the planning and management of implant patients.1
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Reference
- Häggman-Henrikson, B., Ali, D., Aljamal, M., Chrcanovic, B.R. Bruxism and Dental Implants: A Systematic Review and Meta-Analysis.J Oral Rehabil. 2024; 51(1): 202-217. https://onlinelibrary.wiley.com/doi/10.1111/joor.13567
