What implants are made of: metal, ceramic, and the surface
A reference on the biomaterials used for dental implants and the surface engineering that drives osseointegration — from commercially pure titanium and titanium alloys to zirconia ceramic and the topography that touches bone.
Use: Materials referenceFocus: Bulk material + surfaceAnchor: Sa roughness classification
01 — Building blocks
Bulk materials and the surface layer
An implant has a structural bulk material (what gives it strength) and an engineered surface (what bone actually contacts). Both matter for integration and longevity.
Metal
Titanium & Ti-6Al-4V
Commercially pure (cp) Ti grades 1–4 — increasing oxygen/iron raises strength
Grade 5 (Ti-6Al-4V) — alloyed with aluminum and vanadium, higher strength
Moderately rough (Sa 1–2 µm) is the documented optimum
Wettability (hydrophilicity) speeds early healing
Modified by blasting, etching, anodizing
02 — Concept selector
Tap a surface or material to see detail
Different processing routes produce different roughness, wettability, and osseointegration behavior. Select one to compare properties and the supporting evidence.
Tap a surface/material to reveal its properties, roughness band, and osseointegration evidence.
Surfaces & materials
TURNED
Machined (turned)
Original Brånemark surface; minimally rough.
SLA
Sandblasted + acid-etched
Subtractive; moderately rough workhorse.
ANODIC
Anodized (TiUnite-type)
Thick, porous anodic oxide layer.
HYDROPHILIC
SLActive (modified SLA)
Chemically modified, super-hydrophilic.
CERAMIC
Zirconia surface
Roughened Y-TZP ceramic.
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03 — Quick reference
Surface roughness categories (Sa)
Wennerberg & Albrektsson classified implant surface roughness by the arithmetic mean height (Sa). Moderately rough surfaces show the optimal bone response.
Category
Sa range
Typical example
Bone response
Smooth
< 0.5 µm
Polished abutment surfaces
Least bone-to-implant contact
Minimally rough
0.5–1.0 µm
Machined / turned
Lower than rougher surfaces
Moderately rough
1.0–2.0 µm
SLA, SLActive, anodized
Optimal — strongest response
Rough
> 2.0 µm
Some plasma-sprayed / blasted
No added benefit; ion-leakage risk
Note: Hydrophilic / highly wettable surfaces (e.g., SLActive) accelerate early osseointegration by promoting protein adsorption, blood-clot adhesion, and faster bone-to-implant contact; the long-term integration of hydrophilic and conventional moderately rough surfaces converges.
Reference
Sources & clinical disclaimer
For licensed clinicians — educational use only. This page summarizes published basic-science literature and is not a substitute for individual clinical judgment, manufacturer instructions, or the standard of care in your jurisdiction. Specific roughness, alloy, and surface values vary by implant system.
Wennerberg A, Albrektsson T. Effects of titanium surface topography on bone integration: a systematic review. Clin Oral Implants Res. 2009;20(Suppl 4):172–184.
Buser D, Broggini N, Wieland M, et al. Enhanced bone apposition to a chemically modified SLA titanium surface. J Dent Res. 2004;83(7):529–533.
Albrektsson T, Wennerberg A. On osseointegration in relation to implant surfaces. Clin Implant Dent Relat Res. 2019;21(Suppl 1):4–7.
Last reviewed: June 2026 · Next review due: June 2027 · Version 1.0
Self-Test
Self-Test
Switch between board-style single-best-answer questions and oral-defense prompts. Commit to an answer before revealing.
1. According to Wennerberg & Albrektsson, which arithmetic-mean surface roughness (Sa) range produces the optimal bone response?
C is correct. Moderately rough surfaces (Sa 1.0–2.0 µm) show the strongest bone-to-implant response. Smoother surfaces integrate less; surfaces rougher than 2 µm give no added benefit and raise ion-leakage and peri-implantitis concerns.
2. Ti-6Al-4V — the alloy frequently used for implant components — corresponds to which ASTM titanium grade?
C is correct. Grades 1–4 are commercially pure titanium (increasing oxygen/iron, increasing strength); Grade 5 is the Ti-6Al-4V alloy (Grade 23 is its ELI/extra-low-interstitial variant). The alloy offers higher strength but contains aluminum and vanadium.
3. What is the principal documented advantage of a chemically modified hydrophilic surface (e.g., SLActive) over conventional SLA?
A is correct. Hydrophilicity accelerates protein adsorption and clot adhesion, raising early bone-to-implant contact; the curves converge with conventional SLA by ~6 weeks. Roughness (Sa) is comparable between the two, and long-term survival is similar.
4. The main rationale for the titanium-zirconium alloy (Roxolid) compared with commercially pure titanium is:
B is correct. Adding zirconium increases tensile/fatigue strength versus cp titanium, allowing narrower implants in limited spaces without sacrificing osseointegration. It is still a metal (not tooth-colored) and is not resorbable.
1. A patient insists on a "metal-free" zirconia implant. Walk the examiner through how you counsel them, comparing zirconia to titanium.
Model answer. Acknowledge the esthetic and biologic appeal (tooth-colored, low plaque affinity, useful in thin biotypes and titanium-hypersensitivity concerns). Then set expectations with evidence: zirconia osseointegrates and shows survival approaching titanium in short-to-medium-term data, but has fewer long-term studies, a real brittle-fracture risk (especially one-piece designs and after grinding), and most systems are one-piece — limiting angulation correction and prosthetic flexibility. Conclude with shared decision-making: titanium remains the most documented standard; zirconia is reasonable in selected esthetic cases with informed consent.
Examiner follow-ups:
One-piece vs two-piece zirconia — implications?
What is the evidence base beyond 10 years?
How does grinding/adjustment affect zirconia strength (phase transformation)?
2. Explain, at the cellular level, how implant surface topography influences osseointegration — and why we don't simply maximize roughness.
Model answer. Increased micro-roughness expands surface area and surface energy, enhancing protein adsorption and fibrin-clot retention, which guides osteogenic cell migration (osteoconduction) and promotes osteoblast attachment, differentiation, and matrix mineralization — increasing bone-to-implant contact and removal torque. However, roughness has an optimum (Sa ~1–2 µm): beyond it there is no further integration benefit, while metal-ion release rises and the rougher surface, once exposed, more readily accumulates biofilm and predisposes to peri-implantitis. Hence "moderately rough," not "as rough as possible."
Examiner follow-ups:
Contact vs distance osteogenesis — how does surface relate?
How does wettability modify this early cascade?
Subtractive vs additive surfaces — examples and trade-offs?
3. Define the surface-roughness categories by Sa and justify which is preferred for an endosseous implant body.
Model answer. Smooth (<0.5 µm), minimally rough (0.5–1.0 µm), moderately rough (1.0–2.0 µm), and rough (>2.0 µm). The implant body is best served by a moderately rough surface, which maximizes bone-to-implant contact and removal torque while avoiding the downsides of excessive roughness (ion leakage, biofilm/peri-implantitis risk). Smooth surfaces are appropriate at the transmucosal/abutment zone, where low plaque retention matters more than bone apposition.