Peri-Implant Inflammation Varies With Different Restorative Emergence Angles: An Histological Evaluation

Area of Science:

• Dental Implantology
• Periodontology
• Biomaterials Science

Background:

• Peri-implant inflammation is a critical factor affecting dental implant success.
• Restorative emergence angle is a key design parameter influencing peri-implant tissue response.
• Understanding the histological impact of emergence angles is crucial for optimizing implant restorations.

Purpose of the Study:

• To histologically evaluate peri-implant inflammatory responses.
• To assess the effect of varying restorative emergence angles (20°, 40°, 60°, 80°) on inflammation.
• To compare inflammatory differences between buccal and lingual implant sites.

Main Methods:

• Bone-level implants were placed in canine hemi-mandibles.
• Customized abutments with standardized restorative angles were immediately connected.
• Histological analysis quantified inflammatory cell infiltration after 24 weeks.

Main Results:

• Inflammatory cell infiltration showed a significant dose-dependent increase with wider restorative angles (p < 0.001).
• Buccal sites exhibited a sharp increase in inflammation beyond 40° (6% at 40° to ~13% at 80°).
• Lingual sites showed a similar but less pronounced inflammatory pattern, with a notable rise at 80° (~12%).

Conclusions:

• Restorative emergence angles greater than 40° are associated with increased peri-implant inflammation.
• Buccal sites are more susceptible to inflammation with wider emergence angles.
• Optimizing emergence angles is essential for maintaining peri-implant tissue health and long-term stability.