Reducing the Risk of Failure: Using Biometric Data to Select All-on-6 or All-on-4 Implants
- Kube Innovation
- 6 hours ago
- 6 min read
Implant failure is an outcome that dentists and patients fervently want to avoid.
Sometimes failure is caused by factors outside a dentist’s control – like patient bone quality/quantity, immune responses, medications, and other factors. But in other instances, dentists can reduce the risk of failure by using biometric data to improve implant design.8
Recent research reinforces this idea, offering dentists placing implants clear guidance on when to use All-on-4 vs. All-on-6 implants based on a simple, widely-available biometric test – a bite force measurement. The research finds that patients with excessive absolute bite force levels may have better outcomes with All-on-6 treatment.1,4,5
To learn more, read on for our team’s review of research into All-on-6 and All-on-4 implant design.
 | The Difference Between Absolute and Relative Bite ForceAbsolute maximum bite force (MBF) is measured in Newtons with a digital gnathodynamometer such as InnobyteTM. MBF is a critical biometric marker because it indicates the total forces that will bear upon dental implants. Relative force, force sequence and location of contact are measured using digital occlusal analysis systems such as T-Scan and OccluSense. These devices provide valuable information but do not measure MBF. InnobyteTM is approved by regulatory bodies for use in a clinical setting. It measures bilateral human bite force and displays the bilateral and total force values on a digital display. |
Literary Review: Research on All-on-6 and All-on-4 Dental Implants in Patients with High Bite Force
Introduction
Dental implants have revolutionized the field of restorative dentistry, offering patients a reliable solution for replacing missing teeth. Among the various implant-based treatments, the All-on-4 concept has gained significant attention. This technique involves the placement of four implants to support a full arch of prosthetic teeth. However, in certain clinical situations, where patients exhibit high bite forces, the All-on-4 approach may not provide sufficient stability for long-term success. Consequently, some practitioners advocate for the use of six implants rather than four. This literature review aims to explore the rationale behind choosing six implants over the All-on-4 system in patients with high bite forces.
The All-on-4 Concept and Its Limitations
The All-on-4 implant system, developed by Dr. Paulo Malo in the 1990s, offers a solution for edentulous patients with the placement of four strategically positioned implants in the upper or lower jaw. Two of these implants are placed in the anterior region, while the other two are positioned at an angle in the posterior regions to maximize available bone volume and improve implant stability. (Jaiswal et al., 2024, (Hassan & Emarah, 2020) This system is often used in patients who require a full-arch restoration and have insufficient bone mass to support a greater number of implants.
While the All-on-4 system has gained widespread acceptance for its efficiency, lower cost, and reduced surgical time, there are certain concerns when it comes to high bite forces. The occlusal forces exerted by the posterior teeth, especially in patients with bruxism or heavy masticatory function, can exceed the tolerable limits of the four-implant system, leading to potential complications such as implant failure, prosthesis fractures, or inadequate load distribution.
Estimating Bite Force—Before the Implants Are Placed One challenge in deciding between All-on-4 and All-on-6 treatment is that the final bite force—the force your implants will actually need to withstand—isn’t present at the time of planning. Before treatment, patients often have low bite force due to missing or compromised teeth. So how do clinicians account for future bite force? The accepted rule of thumb in both clinical practice and research is that a patient’s bite force will roughly triple after receiving full-arch implants. For example, an edentulous patient exerting 300N of bite force before treatment is expected to exert around 900N after implant placement. This projected increase plays a key role in determining whether All-on-6 is a more appropriate option for patients expected to generate high bite forces once restored.  |
High Bite Force and Its Impact on Implant Stability
Bite force refers to the pressure exerted by the teeth when the jaws come together, and it varies widely among individuals depending on factors like age, gender, dental health, and parafunctional habits (e.g., bruxism). Studies have shown that bite forces in individuals with intact natural teeth can range from 650 to 1000N on average, but individuals with parafunctional habits may exert forces upwards of 1250 N or more.
Research indicates that the high bite forces observed in patients with heavy occlusal demands can significantly affect the stability and long-term success of dental implants. (Flanagan, 2017, Steigenga et al., 2003) Implants are designed to withstand substantial loads, but the forces generated by patients with high bite force or bruxism may result in overloading of the implant-supported prosthesis. Over time, this can lead to the failure of the implant osseointegration process, resulting in implant mobility, bone resorption, and the need for implant replacement.
In the case of the All-on-4 system, the distribution of occlusal forces across only four implants may not be sufficient to resist the stress generated by heavy occlusion. (Tolstunov, 2006) The posterior implants, especially when placed at an angle, may be subject to unfavorable loading conditions, which can contribute to implant failure and prosthetic complications. Several studies have highlighted that the All-on-4 system may not be ideal for patients with high bite forces, particularly those who require significant functional loading, such as athletes, individuals with bruxism, or those with strong masticatory function.
Advantages of Six or more Implants for High Bite Force Patients
To address the limitations of the All-on-4 system, clinicians have proposed the use of six implants or more in patients with high bite forces. The addition of two additional implants can offer several advantages (Bhering et al., 2016, Pandey et al., 2023, Jaiswal et al., 2024 ):
Improved Load Distribution: By increasing the number of implants, the load applied during mastication is more evenly distributed across the implant-supported prosthesis. This can reduce the risk of overloading individual implants, which may lead to failure or complications. The increased number of implants also helps in achieving a more balanced distribution of forces, minimizing the risk of stress concentrations that may cause bone loss or implant failure.
Enhanced Stability: Six implants provide greater overall stability for the prosthetic arch. The distribution of the implants throughout the jaw enhances the ability to withstand the forces generated during chewing. This is particularly important in patients with high bite forces, where the risk of implant failure is heightened with fewer implants.
Better Bone Utilization: In cases where the bone volume is adequate, the placement of six implants can better utilize the available bone structure, improving the overall prognosis of the treatment. In contrast, the All-on-4 technique may not always take full advantage of the bone volume, especially in cases where there are variations in bone density or quality.
Increased Longevity: Research suggests that the use of six implants may result in a longer-lasting and more durable solution for patients with high bite forces. The ability to evenly distribute occlusal forces reduces the likelihood of prosthesis fractures, implant mobility, or other complications that may arise from overloading.
Evidence Supporting Six Implants or More
Several finite element analysis studies have evaluated the efficacy of six implants in the restoration of full arches (Silva et al., 2010, Pandey et al., 2023, Jaiswal et al., 2024). A study by Jaiswal et al. (2024) compared the maximum stress of implant-supported prostheses with four versus six implants and found that six-implant restorations had a significant reduction in maximum stress values compared to the All-on-4 system. These elevated stress values can cause complications in patients with excessive bite force due to the proportional increase in stress on the restoration.
Moreover, short-term follow-up studies have shown that patients with six implants experience fewer issues related to prosthetic fractures and implant failures when compared to those with four implants. The added implants enhance the overall biomechanical stability of the restoration and contribute to better bone preservation over time. (Hassan & Emarah, 2020)
Conclusion
The All-on-4 system has proven to be a successful treatment option for many edentulous patients; however, its limitations become more apparent in patients with high bite forces. The reduced number of implants can compromise the distribution of occlusal forces, leading to potential complications such as implant failure and prosthetic issues.
For patients with high bite forces, the use of six implants offers several advantages, including better load distribution, increased stability, and enhanced longevity of the restoration. Clinical evidence supports the idea that six-implant restorations provide a more reliable and durable solution for patients with heavy masticatory demands, making it a preferable option in such cases. Further research and long-term studies are needed to fully assess the comparative success rates of these two systems across diverse patient populations.
References
Bhering, C. L. B., Ferraz Mesquita, M., Takanori Kemmoku, D., Yoshito Noritomi, P., Xediek Consani, R. L., & Ricardo Barão, V. A. (2016). Comparison between all-on-four and all-on-six treatment concepts and framework material on stress distribution in atrophic maxilla: A prototyping guided 3D-FEA study. Materials Science and Engineering C, 69, 715-725. http://dx.doi.org/10.1016/j.msec.2016.07.059
Flanagan, D. (2017, June 27). Bite force and dental implant treatment: a short review. Medical Devices: Evidence and Research, 10, 141-148. https://doi.org/10.2147/MDER.S130314
Hassan, S. S. M., & Emarah, A. A. E. B. M. (2020, Janurary 1). All on 4 Versus All on 6 implant concepts for rehabilitation of edentulous maxilla. Short term randomized clinical and radiographic study. Egyptian dental journal, 66, 659-670. 10.21608/edj.2020.79138
Jaiswal, S. B., Jain, S., & Jain, V. (2024, October 13). Evaluation and Comparison of Stresses Between All-on-4 and All-on-6 Treatment Concepts With Three Different Prosthetic Materials in the Maxilla: A Finite Element Analysis Study. Cureus, 16(10). 10.7759/cureus.71362
Pandey, A., Durrani, F., Kumar Ra, S., Kumar Singh, N., Singh, P., Verma, R., & Kumar, J. (2023). Comparison between all‑on‑four and all‑on‑six treatment concepts on stress distribution for full‑mouth rehabilitation using three‑dimensional finite element analysis: A biomechanical study. Journal of Indian Society of Periodontology, 27(2), 180-188. 10.4103/jisp.jisp_278_22
Silva, G. C., Mendonça, J. A., Lopes, L. R., & Landre Jr, J. (2010). Stress patterns on implants in prostheses supported by four or six implants: a three-dimensional finite element analysis. International Journal of Oral & Maxillofacial Implants, 25(2), 239-246. https://pubmed.ncbi.nlm.nih.gov/20369081/
Steigenga, J. T., Al-Shammari, K. F., Nociti, F. H., Misch, C. E., & Wang, H.-L. (2003, December). Dental Implant Design and Its Relationship to Long-Term Implant Success. Implant Dentistry, 12(4), 306-317. 10.1097/01.ID.0000091140.76130.A1
Tolstunov, L. (2006, December). Dental Implant Success-Failure Analysis: A Concept of Implant Vulnerability. Implant Dentistry, 15(4), 341-346. 10.1097/01.id.0000239333.24384.5d
