Dental implants have become the preferred treatment option for replacing missing teeth due to their high success rates and ability to restore function and aesthetics (1). However, long-term success is influenced by various biomechanical factors, including occlusal load distribution and peri-implant bone stress (2). The occlusal scheme plays a crucial role in determining how forces are transmitted to the implant and surrounding bone, potentially affecting implant stability and longevity (3).

Occlusal loading on implants differs significantly from natural teeth due to the absence of the periodontal ligament, which in natural dentition serves as a shock absorber and proprioceptive mechanism (4). Consequently, excessive or unfavorable forces can lead to microstrain and peri-implant bone loss, jeopardizing implant survival (5). Studies have indicated that different occlusal schemes, such as canine-guided occlusion, group function occlusion, and balanced occlusion, influence stress distribution around implants differently (6). Understanding the biomechanical implications of these occlusal schemes is essential for optimizing implant-supported prosthetic designs.

Finite Element Analysis (FEA) is a widely used computational tool that allows for the assessment of stress distribution in complex structures, including dental implants and surrounding bone (7). It provides a detailed understanding of how various occlusal schemes impact peri-implant bone stress, aiding in the development of biomechanically favorable treatment approaches (8). Previous studies have demonstrated that occlusal loading patterns influence implant longevity, but further research is required to establish the optimal occlusal scheme for reducing peri-implant stress (9).

This study aims to evaluate the effect of different occlusal schemes on peri-implant bone stress using finite element analysis. The findings may provide valuable insights into the biomechanical implications of occlusal schemes, guiding clinicians in selecting appropriate occlusal designs for implant-supported prostheses.

Finite Element Model Development

A three-dimensional finite element model (FEM) was developed to simulate the biomechanical behavior of a dental implant under different occlusal schemes. The model represented a mandibular posterior segment, incorporating cortical and cancellous bone, an endosseous titanium implant (4.0 mm diameter, 10.0 mm length), an abutment, and a prosthetic crown. The material properties of bone, implant, and prosthetic components were assigned based on previous studies, considering isotropic, homogeneous, and linear elastic behavior.

Occlusal Schemes and Load Application

Three occlusal schemes were analyzed in this study:

1. Canine-Guided Occlusion (CGO) – Occlusal forces were directed through the canines during lateral movements.
2. Group Function Occlusion (GFO) – Occlusal forces were distributed among multiple posterior teeth during lateral excursions.
3. Balanced Occlusion (BO) – Occlusal contacts were maintained on both working and non-working sides to evenly distribute forces.

A vertical occlusal force of 200 N was applied to the prosthetic crown in all models, simulating functional masticatory loading. The load was distributed based on each occlusal scheme to evaluate its effect on peri-implant bone stress.

Boundary Conditions and Meshing

The FEM was constructed and meshed using tetrahedral elements to ensure accurate stress distribution analysis. The implant-bone interface was assumed to be fully osseointegrated. Fixed boundary conditions were applied at the base of the bone model to restrict movement, replicating in vivo conditions.

Stress Analysis

Von Mises stress distribution in peri-implant cortical and cancellous bone was analyzed using finite element software. The maximum stress values at the crestal bone level were recorded for each occlusal scheme. Comparisons were made to assess which occlusal pattern resulted in the most favorable stress distribution.

Statistical Analysis

Descriptive analysis was performed to compare stress values among different occlusal schemes. The findings were interpreted based on the potential impact of stress distribution on peri-implant bone health and long-term implant success.

The finite element analysis revealed differences in peri-implant bone stress across the three occlusal schemes. The highest maximum stress was observed in the canine-guided occlusion (145 MPa), followed by group function occlusion (120 MPa), while the lowest stress was recorded in balanced occlusion (95 MPa) (Table 1). Similarly, the mean peri-implant stress values followed a similar trend, with canine-guided occlusion showing the highest mean stress of 110 MPa, group function occlusion at 95 MPa, and balanced occlusion at 80 MPa.

Stress concentration was primarily observed at the crestal bone level in all models, with more localized stress peaks in canine-guided occlusion. In contrast, balanced occlusion demonstrated a more uniform stress distribution, which may contribute to improved peri-implant bone health. The findings suggest that occlusal scheme selection plays a critical role in reducing peri-implant bone stress, potentially influencing long-term implant success (Table 1). ​​

Table 1: Peri-implant Bone Stress under Different Occlusal Schemes

The findings of this study highlight the significant impact of different occlusal schemes on peri-implant bone stress distribution. The finite element analysis demonstrated that canine-guided occlusion (CGO) exhibited the highest peri-implant bone stress, while balanced occlusion (BO) resulted in the lowest stress, suggesting that occlusal force distribution plays a crucial role in implant biomechanics. These results align with previous studies emphasizing that excessive occlusal forces can lead to microstrain and peri-implant bone loss, potentially compromising implant longevity (1,2).

One of the major concerns in implant-supported prosthetics is the absence of the periodontal ligament, which limits shock absorption and proprioception compared to natural dentition (3). This biomechanical difference makes implants more susceptible to occlusal overload, which can contribute to crestal bone loss and implant failure (4,5). In this study, CGO resulted in localized stress concentration, particularly in the crestal bone region. This finding is consistent with previous reports suggesting that CGO may generate excessive lateral forces, leading to increased biomechanical complications in implant-supported prostheses (6,7).

Conversely, group function occlusion (GFO) exhibited lower stress values than CGO but higher than BO. This suggests that distributing occlusal forces among multiple posterior teeth can reduce peak stresses but may not be as effective as BO in achieving uniform stress distribution (8). Studies have shown that occlusal schemes involving multiple posterior contacts during function can help in better load-sharing, thereby reducing stress concentration in the peri-implant bone (9,10).

The balanced occlusion scheme demonstrated the most favorable stress distribution in this study, with the lowest peri-implant bone stress values. This outcome supports the hypothesis that occlusal forces distributed evenly across both working and non-working sides may minimize peri-implant overload and reduce the risk of crestal bone resorption (11). Several finite element studies have also reported that balanced occlusion can improve implant stability by enhancing load distribution and reducing peak stress on the implant-bone interface (12,13).

The clinical implications of these findings suggest that occlusal scheme selection should be tailored to optimize biomechanical loading in implant-supported prostheses. Although canine-guided occlusion is commonly recommended in natural dentition due to its protective function in lateral excursions, its applicability in implant-supported restorations should be carefully considered due to the risk of excessive stress on peri-implant bone (14,15). Instead, occlusal designs that promote even force distribution, such as balanced occlusion, may be more beneficial for long-term implant success.

Despite the insights provided by this study, some limitations should be acknowledged. The finite element model assumed idealized bone-implant contact with full osseointegration, which may not fully replicate clinical conditions. Additionally, variations in bone quality, implant angulation, and prosthetic materials were not considered, which could influence stress distribution. Future studies incorporating clinical validation and patient-specific modeling are needed to strengthen the understanding of occlusal biomechanics in implant dentistry.

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