Understanding the Differences – Leveraging Biological Advantages

In implant dentistry, two fundamental implant designs have been established: bone-level and tissue-level implants.
Each design follows a distinct surgical and prosthetic protocol.
It has implications for soft tissue stability, crestal bone preservation, esthetics, and long-term success.

This article outlines both implant types in detail.
It also explains why, from a biological and clinical standpoint, the tissue-level concept offers advantages – especially when working with zirconia implants.

What Are Bone-Level Implants?

Bone-level implants are placed at the level of crestal bone. The implant shoulder sits flush with or slightly below the bone crest.
A separate abutment is then connected, indicating that the implant-abutment interface is located at or below the bone level.

Key Characteristics

Placement at crestal bone level
Two-piece design with separate abutment
Implant–abutment connection located at or subcrestal to bone
Used in esthetic zone and other regions

Potential Challenges

Micro-movement or microgaps at the implant-abutment interface
Risk of bacterial infiltration
Crestal bone remodeling and gingival ressecion
Repeated soft tissue manipulation during uncovering and abutment changes

Historically, bone-level systems have evolved primarily within titanium implantology.
Subcrestal placement is often required to mask the metallic shoulder in the esthetic zone to avoid gray shadows in patients with a thin gingival profile.

What Are Tissue-Level Implants?

Tissue-level implants are placed such that the implant shoulder is positioned within the soft tissue.
Therefore, The implant-prosthetic interface is located above the crestal bone.

Key Characteristics

Placement at soft tissue level
Transmucosal healing
Implant shoulder positioned outside the crestal bone
Potentially lower impact on crestal bone levels

The core principle of the tissue-level concept is to respect the biological width from the outset and avoid disturbing the critical bone-soft tissue interface.

The Decisive Difference: Biology

The fundamental distinction between bone- and tissue-level implants is not primarily mechanical but biological.

With bone-level implants, the implant-abutment interface lies at or near the crestal bone. Even minimal microgaps or bacterial colonization may contribute to inflammatory responses, which could affect crestal bone.

In tissue-level designs, this interface is positioned coronally, away from the sensitive bone area.
This may support:

Maintaining crestal bone
Preserving biological width
Minimizing manipulation of peri-implant soft tissue

From a long-term stability and peri-implant health perspective, the tissue-level principle provides clear biological benefits.

Why Tissue Level Is Especially Critical for Zirconia Implants

While bone-level positioning is often necessary in titanium systems for esthetic masking, the paradigm shifts fundamentally when working with zirconia.

Zirconia enables a biologically distinct approach.

1. The Zirconia-Epithelial Attachment

Soft tissue attaches to the zirconia material. Histological studies have demonstrated stable epithelial and connective tissue adhesion to zirconia implant surfaces, often described as zirconia epithelial attachment.¹^-²

This can contributo to:

A more stable soft tissue interface around the implant collar
May support local defense against bacterial colonization
No need for a critical subcrestal interface

Placing a zirconia implant at the bone level may compromise this soft tissue interface.

2. A Wider — Not Narrower — Cervical Design

Many titanium implants feature a narrow transition zone. In contrast, zirconia tissue level implants are designed with a wider cervical collar.

A wider cervical collar may help support:³^-⁴

Soft tissue stability
Maintain papilla height
Contribute to favorable esthetic outcomes
Functionally “closing the immunological door”

This concept is consistently effective only within a tissue-level positioning strategy.

3. Bone Can Taper Naturally

Zirconia does not exhibit ductility at room temperature. Unlike titanium, it does not flex when under load.
As a result, the bone can taper naturally around zirconia implants without mechanical stress-induced resorption.

The clinical implications may include:

Potentially reduced need for augmentation procedures
Support for preservation of papilla height
Prevention of unnecessary smoothing of sharp ridges

Again, proper tissue-level placement is essential to achieve this biological advantage.

Our Clinical Conclusion: Consistent Tissue-Level Positioning

Based on biological, mechanical, and clinical considerations, we made a deliberate decision.

All implants were consistently positioned as tissue-level implants.

This decision is not marketing-driven. It is based on:

More than 20 years of experience with ceramic implants
Tens of thousands of placed implants
Daily clinical application at the SWISS BIOHEALTH CLINIC
Continuous product development informed by real-world practice.

Engineering for Biological Stability

Dynamic Thread® – Apical Primary Stability

The apical portion of our implants features the self-cutting Dynamic Thread® design.

Up to 2.5× thread depth
Low thread pitch (7°)
Bone condensation in Class III and IV bone
Creation of healing chambers in dense bone
Insertion torque: 35 Ncm

The result aimed at achieving high primary stability and controlled load distribution, based on design principles.

Cervical Micro-Thread

In the region of highest mechanical stress, a 0.04 mm micro thread:

Adapts to cortical bone
Avoids harmful compression
Increases core diameter
Increases implant surface area in crestal bone and distributes forces reducing the risk of implant fracture

Tapered Implant Design Instead of Cylindrical Geometry

Ceramics do not dissipate iatrogenic heat. Therefore, we intentionally avoided cylindrical implant designs and aggressive cutting flutes.

Our tapered implants:

“Drop in” more than 70% in Class I bone
Minimize friction
Prevent overheating
Create healing chambers
May support faster initial bone healing compared to traditional designs

Biology before mechanics.

Two-Piece — Yet Still Tissue-Level

Even our two-piece system (SDS2.2) remains true to the tissue-level principle.

The implant-abutment interface is not located in bone
The connection is positioned within the lower collar region
After cementation of the post into the implant, it functions as a prosthetic platform just as a one-piece system
No micro movements or other prosthetic components (=> no risk of screw-loosening)

This approach offers prosthetic flexibility while respecting biology.

Conclusion: Tissue Level Is Not a Design — It Is a Biological Concept

The comparison between tissue- and bone-level implants demonstrated the following:

Bone level is a historically titanium-driven concept.

Tissue-level — when properly implemented — is a biologically oriented approach that may:

Support maintenance of crestal bone
Contribute to soft tissue stability
Help preserve papilla height
Promote overall peri-implant health
Potentially provide favorable esthetic outcomes

With zirconia as the material of choice⁵^-⁶, titanium implants positioned at bone level are no longer necessary⁷.

We do not consider implant dentistry in metallic terms;
we think biologically.

Therefore, our implants are consistently tissue-level.

FAQ – Soft Tissue Level vs. Bone Level Implants

1. What is the difference between bone-level and tissue-level implants?

Bone-level implants are placed at the level of the crestal bone, with the implant–abutment interface located at or below bone level. Tissue-level implants position the implant shoulder within the soft tissue, placing the prosthetic interface above the crestal bone.

2. What are the biological differences between bone-level and tissue-level implants?

The primary distinction is biological rather than mechanical. In bone-level designs, the implant–abutment interface lies at or near the crestal bone, whereas tissue-level implants position this interface coronally, away from the sensitive bone area.

3. How can implant position influence crestal bone levels?

Microgaps or bacterial colonization at the implant–abutment interface located near the crestal bone may contribute to inflammatory responses, which could affect crestal bone remodeling. Positioning this interface coronally may help mitigate this effect.

4. Can tissue-level implants support preservation of the biological width?

The tissue-level concept is designed to respect the biological width from the outset, potentially supporting stable bone–soft tissue relationships by avoiding disruption of the crestal bone interface.

5. Why is the implant–abutment interface considered biologically relevant?

The implant–abutment interface may present microgaps that can be susceptible to bacterial infiltration. When located near the crestal bone, this interface may influence peri-implant tissue responses.

6. Why is tissue-level positioning particularly relevant for zirconia implants?

With zirconia implants, tissue-level positioning allows the prosthetic interface to remain outside the crestal bone, supporting a biologically distinct approach compared to titanium-based bone-level concepts.

7. What is meant by zirconia–epithelial attachment?

Histological studies have shown stable epithelial and connective tissue adhesion to zirconia implant surfaces, often referred to as zirconia–epithelial attachment.¹–²

8. How may zirconia implants influence soft tissue stability?

The interaction between soft tissue and zirconia surfaces may contribute to a stable soft tissue interface around the implant collar and support local defense against bacterial colonization.¹–²

9. What role does the cervical design of zirconia implants play?

Zirconia tissue-level implants are often designed with a wider cervical collar, which may help support soft tissue stability, maintain papilla height, and contribute to favorable esthetic outcomes.³–⁴

10. How can implant material affect bone adaptation?

Zirconia does not exhibit ductility at room temperature. Unlike titanium, it does not flex under load, allowing bone to taper naturally around the implant without mechanically induced resorption.

11. Why is subcrestal placement not required for zirconia implants?

Zirconia does not produce metallic discoloration of the soft tissue, eliminating the need for subcrestal placement for esthetic masking as commonly required with titanium implants.⁵–⁷

12. How does tissue-level positioning relate to long-term peri-implant health?

By positioning the prosthetic interface away from the crestal bone and minimizing repeated soft tissue manipulation, tissue-level concepts may support stable peri-implant conditions over time.

13. Can tissue-level placement support papilla height?

Tissue-level positioning combined with appropriate cervical design may help support preservation of papilla height by allowing physiological bone and soft tissue adaptation.³–⁴

14. Is tissue level primarily a design feature?

Tissue level is best understood as a biological concept rather than a purely geometric design, focusing on preserving the bone–soft tissue interface.

15. Why are modern zirconia implant systems consistently tissue-level?

When properly implemented, tissue-level placement with zirconia supports a biologically oriented implant approach without the need for titanium-driven bone-level positioning.⁵–⁷

References:

1. van Brakel R, Noordmans HJ, Frenken J, de Roode R, de Wit GC, Cune MS. The effect of zirconia and titanium implant abutments on light reflection of the supporting soft tissues. Clin Oral Implants Res. 2011 Oct;22(10):1172–8.

2. Al Qahtani WMS, Schille C, Spintzyk S, Al Qahtani MSA, Engel E, Geis-Gerstorfer J, et al. Effect of surface modification of zirconia on cell adhesion, metabolic activity and proliferation of human osteoblasts. Biomed Tech (Berl). 2017 Feb 1;62(1):75–87.

3. Balmer M, Pirc M, Kraus RD, Naenni N, Thoma DS, Jung RE. Three Materials for Monolithic Crowns on Zirconia Implants: One-Year Results of a Randomized Clinical Trial. Int J Prosthodont. 2025 June 30;0(0):1–21.

4. Thoma DS, Ioannidis A, Cathomen E, Hämmerle CHF, Hüsler J, Jung RE. Discoloration of the Peri-implant Mucosa Caused by Zirconia and Titanium Implants. Int J Periodontics Restorative Dent. 2016;36(1):39–45.

5. Romanos GE, Delgado-Ruiz R. Macroscopic Evidence of Surface Changes of Dental Implants After Insertion and Removal in Dense Bone: In Vitro Study. Int J Oral Maxillofac Implants. 2022;37(2):e41–9.

6. Romanos GE, Fischer GA, Rahman ZT, Delgado-Ruiz R. Spectrometric Analysis of the Wear from Metallic and Ceramic Dental Implants following Insertion: An In Vitro Study. Materials (Basel). 2022 Feb 4;15(3):1200.

7. Kim S, Jung U, Cho K, Lee J. Retrospective radiographic observational study of 1692 Straumann tissue-level dental implants over 10 years: I. Implant survival and loss pattern. Clin Implant Dent Related Res 2018;20(5):860–866. doi:10.1111/cid.12659.

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