Titanium has been long established as the standard bearer for dental implant material. However, when considering the factors that can affect dental implant success both long and short term, one of the most crucial is undoubtedly the implant’s surface.

Why dental implant surface matters

At first glance, titanium might seem a strange choice for dental implant material. Though it has high strength, great biocompatibility, low level of toxicity potential and high resistance to corrosion, titanium in its pure state is highly reactive.1 When it interacts with oxygen, however, a surface layer of titanium oxide (TiO2) is formed, stabilizing the surface and allowing osseointegration to occur.2

Surface has an important role in healing time for osseointegration and, ultimately, the success of implant treatment. 3 It is the only part of the implant exposed to the surrounding oral environs, and its chemical, physical, mechanical, and topographic characteristics are all crucial to maximizing the likelihood of successful osseointegration. 4

TiUnite dental implant surface

Figure 1 Scanning electron microscopy image showing a dense blood coagulation at the surface of the TiUnite implant. Blood coagulation is the first step of the peri-implant bone healing; a strong initial reaction indicates the osteoconductivity of TiUnite.

Developments in implant surface treatments

Today, there is a wide range of titanium dental implant surfaces. P-I Brånemark’s initial implants over 50 years ago, had a smooth, turned surface, and as he described, they require three to six months of healing before successful implant loading can take place. 5

Since then, the design of dental implants and their surfaces have frequently changed and evolved over time to allow for improved osseointegration and better long-term implant survival rates. There are three distinct groups of methods through which implant surfaces can be modified at manufacture:

  • Mechanical treatments: These include grinding, blasting and machining to create rougher or smoother surfaces.
  • Chemical treatments: Conducted with acids, alkali, sol gel or through anodization, among other methods, chemical treatments alter the implant surface’s roughness and composition. 6
  • Physical treatments: These treatments include plasma spraying and ion deposition.

Some of the more common titanium implant surface treatments used in recent years include anodization, and blasting and acid etching. Anodization, which works by increasing the thickness of the implant’s TiO2 layer, moderately roughening it, and improving osteoconductivity, has been shown to enhance osseointegration. 7

Sandblasting and acid etching, on the other hand, remove parts of the implant material, creating small irregularities and a roughened surface that can encourage rapid osseointegration. 8

Different dental implant surfaces

Figure 2 Low (top) and high (bottom) magnified scanning electron images of dental implants produced with different methods: anodization (left) and sandblasting-acid etching (right). While methods result in a microrough topography favorable for osseointegration, they vary in morphology and composition.

Confocal microscopy image from dental implant surface

Figure 3 Confocal microscopy image of blood components adhered and reacted to the TiUnite implant surface. Blood cells and proteins immediately attach to the surface and initiate the coagulation process leading to the formation of fibers mainly composed of a blood plasma protein – fibrin – and platelets. These fibers grow into a dense network which is the provisional tissue that will support bone healing around the implant.

Though these treatment methods vary, their intended outcome remains the same: To provide a strong biological and mechanical connection to the alveolar bone in a short time period and, ultimately, reduce the likelihood of implant failure. 9 Despite the range of implant surfaces being developed over many years, their relative rates of long-term success are only just starting to be compared.

Confocal microscopy, 3D reconstruction of the early blood-implant surface interface

Figure 4 Confocal microscopy, 3D reconstruction of the early blood-implant surface interface. The blood components adhere immediately and over the whole implant surface. Fibrin fibers, early sign of the formation of a blood coagulum span between threads of the implant.

Comparing implant surfaces: A new study

A new study, led by Professor Ann Wennerberg, has sought to correct this gap in the literature through a systematic review of the long-term clinical outcomes of implant treatment with different surfaces.

The study showed that implants with the anodized surface, Nobel Biocare’s TiUnite, showed the best survival rate (98.5%) with at least 10 years’ follow-up. 10

Comparing the performance of implants with anodized, blasted, turned, titanium plasma-sprayed, and sandblasted and acid-etched surfaces, Wennerberg found that there was a mean marginal bone loss for all implant surface types in the study of less than 2 mm, even for implants with older designs and surfaces, and well within what is considered to be an acceptable level. 11

Largest ever meta-analysis of a single implant brand

In their 2017 study, Profs. Mattias Karl and Tomas Albrektsson analyzed outcomes from 4,694 clinically evaluated patients treated with 12,803 TiUnite implants reported in 106 studies. 12

Their results confirm that implants with the TiUnite surface have a remarkably low early failure rate and very good long-term survival; at implant level, the projected survival rate was over 99% after one year, and 95.1% after 10 years.* As one of the most clinically researched implant surfaces on the market 13, TiUnite has been proven to enhance osseointegration 14 and maintain implant stability during the critical healing phase. 15 As a result, it is able to play a vital role in assisting clinicians to meet patient demands for shorter time-to-teeth.

*Results of regression analysis. Details can be found in full publication.

More to explore

Key visual caption: Confocal microscopy z-stack projection shows fluorescent staining of fibrin (green), nuclei of white blood cells (blue) and platelets (red) on a TiUnite surface implant (NobelParallel CC).

References

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    Ivanoff, C. J., et al. (2003). Histologic evaluation of bone response to oxidized and turned titanium micro-implants in human jawbone. Int J Oral Maxillofac Implants 18(3): 341-348. Read on PubMed

  8. Barfeie A, Wilson J, Rees J. Implant surface characteristics and their effect on osseointegration. British Dent J 2015;218:1-9. Read on PubMed
  9. Wennerberg A, Albrektsson T, Chrcanovic B. Long-term clinical outcome of implants with different surface modifications. Eur J Oral Implantol 2018;11(supp1): S123–S136. Read on PubMed
  10. Wennerberg A, Albrektsson T, Chrcanovic B. Long-term clinical outcome of implants with different surface modifications. Eur J Oral Implantol 2018;11(supp1): S123–S136. Read on PubMed
  11. Misch CE, et al. Implant success, survival, and failure: the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference. Implant Dent 2008;17(1):5–15. Read on PubMed
  12. Karl M, Albrektsson T. Clinical performance of dental implants with a moderately rough (TiUnite) surface: a meta-analysis of prospective clinical studies. Int J Oral Maxillofac Implants 2017;32(4):717–734. Read on PubMed
  13. TiUnite literature search. Nobel Biocare Services AG. September, 2018.
  14. Ivanoff CJ, Widmark G, Johansson C, et al. Histologic evaluation of bone response to oxidized and turned titanium micro-implants in human jawbone. Int J Oral Maxillofac Implants 2003;18:341-348. Read on PubMed
  15. Glauser R, Portmann M, Ruhstaller P, et al. Stability measurements of immediately loaded machined and oxidized implants in the posterior maxilla. A comparative clinical study using resonance frequency analysis. Appl Osseointegration Res 2001;2:27-29. Access on ResearchGate

Posted by Chris Kendall