Implant-Supported vs. Tooth-Supported Restorations: Long-Term Biomechanical Impact

With the widespread adoption of implant dentistry in most practices, clinicians frequently face the question of whether to restore missing teeth using implant-supported prostheses or conventional tooth-supported restorations. While both options can deliver excellent functional and esthetic results, their long-term biomechanical impact differs significantly.

Understanding these differences allows us to make better treatment plants, minimize complications, and extend the survival of our restorations.

Biomechanical Principles

Natural Tooth Biomechanics

Natural teeth are anchored by the periodontal ligament (PDL), which provides proprioception and physiologic mobility. The PDL absorbs functional loads, distributing stress to the surrounding alveolar bone and preventing damage to the teeth tissues. Under occlusal force, teeth exhibit micromovement of approximately 50-200 µm, working as a cushion and protecting hard and soft tissues.

Implant Biomechanics

In contrast, dental implants achieve ankylotic fixation with bone through osseointegration, with virtually no physiologic mobility (barely 3-5 µm). With this rigidity, the occlusal forces concentrate directly onto peri-implant bone, potentially increasing stress concentrations at the crestal level. Unlike teeth, implants lack proprioceptive feedback, requiring clinicians to design occlusion to avoid overloading.

Most times, the behavior and performance of implant systems are tightly related to implant selection, design, planning, and other surface features that provide a stable and strong anchorage.

Long-Term Survival Rates

Tooth-Supported Restorations

Fixed partial dentures have decades of documented success. Ten-year survival rates average 70-80%, with biological complications like caries, endodontic failure, and periodontal disease being the leading causes of failure. Yet, the main biomechanical risk is still secondary caries at abutments, particularly when oral hygiene is compromised.

Implant-Supported Restorations

Implant-supported single crowns and fixed partial prostheses report 10-year survival rates of 85–95%. However, mechanical complications, such as screw loosening, ceramic chipping, or implant fracture, are more common than biological failure. Despite its high survival rates, peri-implantitis remains the main long-term biological issue, usually related to plaque accumulation, emphasizing the need for supportive care and patient compliance.

Biomechanical Stress Distribution

Tooth-Supported Bridges

Fixed partial dentures (FPDs) allow force distribution across abutment teeth through the PDL. This cushioning mechanism reduces stress concentrations, but creates a risk of overloading when one pillar is periodontally compromised or endodontically treated. Unequal mobility between pillars may contribute to debonding or fracture of the restoration.

Implant-Supported Prostheses

When osseointegration is completed and rigid, it transfers occlusal stresses directly to the surrounding bone. This stress concentration depends directly on implant design, angulation, number of fixtures, and occlusal scheme. Cantilevered designs, inadequate implant number, or unfavorable occlusal forces can increase the risk of bone loss or long-term mechanical complications.

Mixed Support: Tooth-Implant Connections

Some cases require combining teeth and implants within a fixed prosthesis. This mixed approach introduces a biomechanical mismatch as teeth move under function while implants remain rigid. While some studies show technical complications and unpredictable load distribution in most of these cases, it can be practical and successful with the appropriate planning when anatomical limitations or other clinical limitations make it necessary. As a result, it’s necessary to assess and plan every case while considering clinical circumstances.

Biological Complications

Caries and Periodontal Disease in Tooth-Supported Restorations

The most frequent biological complications of FPDs include recurrent caries and periodontal deterioration due to plaque retention, typically related to inadequate hygiene and other patient-related factors. Long-span bridges and cases with compromised oral hygiene are particularly vulnerable to these complications. Yet, endodontic complications, such as pulp necrosis or failure of large restorations, also reduce survival rates.

Peri-Implant Diseases

For dental implant restorations, peri-implant mucositis and peri-implantitis represent the main biological risks. In fact, the prevalence of peri-implantitis is approximately 10–20% of implants after 5–10 years. As a result, implant restorations require strict maintenance and home care to prevent inflammation, progressive bone loss, and implant failure. 

Mechanical Complications

Tooth-Supported Restorations

The leading mechanical complications in FPDs include:

• Fracture of ceramic
• Deboding of retainers
• Fracture of pillar tooth

While some cases can be repaired, most of these failures often require replacement of the entire prosthesis.

Implant-Supported Restorations

Implant restorations show higher rates of technical complications when compared with tooth-supported restorations. These complications include:

• Screw loosening
• Loss of retention
• Ceramic chipping or fracturing
• Framework fracture
• Implant body fracture in rare cases

In this case, the rigid anchorage of the implant magnifies the biomechanical consequences of occlusal overload, highlighting the importance of an appropriate implant design and prosthetic planning.

Occlusal Considerations

In the case of tooth-supported FPDs, occlusion can be designed similarly to natural dentition thanks to the effect of PDL cushioning. Contrarily, implant-supported prostheses require adjusted occlusal schemes, such as:

• Light centric contacts
• Minimized lateral forces
• Elimination of cantilevers whenever possible

Besides prosthetic design and occlusal force distribution, clinicians must also consider protective measures like night guards, especially when dealing with bruxers in full-arch implant restorations.

Long-Term Patient-Related Factors

Oral Hygiene and Maintenance

Patients with poor plaque control are at high risk of caries, in tooth-supported bridges and crowns, and peri-implantitis in implant prostheses. Current studies consistently show that professional maintenance and patient adherence considerably reduce complications across both restoration types.

Systemic Conditions

Diabetes, smoking, osteoporosis, and other systemic factors have negative impacts on both prosthesis types, while their mechanisms differ. For teeth, they accelerate periodontal breakdown, while increasing susceptibility to peri-implantitis in the case of implants.

Clinical Decision-Making

Number and Condition of Tooth Structure

When adjacent teeth are intact and caries-free, preserving them may favor implant-supported restorations to avoid irreversible preparation. Preserving natural tooth structure is especially valuable in younger patients. However, if adjacent teeth already require crowns, an FPD may be justified since tooth preparation aligns with their restorative needs.

Periodontal and Caries Risk Profile

In case of patients with a history of periodontal disease, the risk of implant complications, including peri-implantitis, is higher. As a result, these cases require meticulous supportive care with a personalized approach to prevent common complications. Conversely, patients prone to recurrent caries may be poor candidates for tooth-supported bridges, since abutment teeth are vulnerable to secondary decay.

Biomechanical Factors

The number, angulation, and quality of potential abutment teeth or implant sites heavily influence outcomes. Long-span bridges with compromised abutments are biomechanically weaker compared to multiple implants supporting the same load. Implants, on the other hand, must be placed with careful occlusal design to prevent overload due to their ankylotic anchorage.

Age and Systemic Health

Younger patients benefit from implants that offer longevity and avoid sacrificing healthy tooth structure. Older patients, or those with systemic conditions like osteoporosis or diabetes, may pose surgical risk or healing limitations, making tooth-supported prostheses more practical and predictable.

Financial and Logistical Considerations

Economic context matters significantly in most countries, particularly in Latin America, where implant cost or access may limit availability. Conventional bridges, while less durable in the long term, can still provide reliable outcomes and predictable behavior for patients unable to pursue implant therapy. 

Maintenance Commitment

Every prosthetic restoration, whether implant or tooth-supported, requires lifelong maintenance. Implants require careful peri-implant care, while FPDs demand vigilant caries prevention and consistent hygiene. Patients' motivation and compliance should weigh heavily in the decision-making.

Ultimately, no single solution is universally superior, requiring a case-by-case and evidence-based approach to ensure that treatment aligns with the patient's risk profile, esthetic expectations, financial realities, and biomechanical integrity.

Future Perspectives

Research is advancing toward biomimetic implant designs that may mimic PDL-like stress distribution, reducing overload risk and significantly improving occlusal performance. Digital planning and CAD/CAM prosthetics also improve biomechanical precision, allowing clinicians to speed every stage of the treatment, from the treatment to the surgical intervention, while reducing the risk of complications and human error.

Longitudinal studies will continue to refine survival estimates, especially in full-arch cases where biomechanical forces are magnified.

Practical Recommendations for Clinicians

• Perform a thorough risk assessment that includes caries risk, periodontal status, occlusal patterns, and systemic factors.
• For implant-supported restorations, design occlusion carefully, avoid cantilevers, and ensure sufficient implant number if required.
• For tooth-supported FPDs, protect abutments with proper preparation and encourage stringent caries control.
• Establish long-term recall and maintenance programs for both approaches to reinforce home care and hygiene.

Conclusion

While both implant-supported and tooth-supported restorations can provide long-term functional and aesthetic outcomes when selected and executed appropriately, they have key differences that require our attention. Implants generally offer higher survival rates and avoid preparation of adjacent teeth, but carry higher risks of mechanical complications and peri-implant disease. On the other hand, tooth-supported restorations remain highly valuable, especially when patient conditions limit implant use.

As clinicians, our decisions should always balance biomechanics, biology, patient risk factors, and practical considerations.

References 

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2. Robinson, D., Aguilar, L., Gatti, A., Abduo, J., Lee, P. V. S., & Ackland, D. (2019). Load response of the natural tooth and dental implant: A comparative biomechanics study. The journal of advanced prosthodontics, 11(3), 169–178. https://doi.org/10.4047/jap.2019.11.3.169

3. Gözen, M., & Güntekin, N. (2025). Comparison of occlusal force distribution and digital occlusal analysis methods of single posterior implant restorations: an in vivo study. BMC oral health, 25(1), 795. https://doi.org/10.1186/s12903-025-06205-w

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