Straumann Presents 'Roxolid™' A New Material Designed To Enhance The Strength And Healing Properties Of Dental Implants

Main Category: Dentistry
Article Date: 23 Sep 2008 - 2:00 PDT

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At the17th Annual Scientific Meeting of the European Association for Osseointegration (EAO) in Warsaw, Poland, Straumann presented a new material that could make dental implants smaller and stronger. The new material, which is called Roxolid™, is an alloy of titanium and zirconium and is the first material to be designed specifically for dental implants.

Roxolid™ is 50% stronger than pure titanium[1], the current material of choice for implants. Exciting preclinical study results presented in Warsaw showed that Roxolid integrated with bone better than pure titanium[2]. The combination of enhanced strength and osseointegration could open the door for a new generation of smaller, safer implants, which would be particularly advantageous in situations where there is limited space between teeth. A further potential advantage could be the use in thin bone (narrow bone ridge), where wider implants would necessitate bone augmentation/grafting procedures.

Engineered and developed by Straumann, Roxolid is currently undergoing clinical trials in 6 countries. Preliminary (6-12 month) observations from the first clinical trial were also presented at the EAO[3] showing very promising survival rates.

Pending regulatory approvals and further positive findings from the broad clinical program, Roxolid implants are expected to become available in initial markets in the course of 2009.

The quest for high performance materials

Pure titanium is well known for its biological compatibility with the human body and its resistance to corrosion. The discovery that bone integrates with titanium (osseointegration) opened the way for its use in orthopaedic surgery and subsequently in implant dentistry, where its physical properties were also important in order to bear the very strong forces of chewing. However, the mechanical properties are limited in the case of small diameter implants or parts, which are needed for narrow spaces (e.g. to replace the lower front teeth). This prompted the use of alternative materials, such as titanium alloys (e.g. Ti-6Al-4V, 'TAV'). However, additional strength came at the price of osseointegration due to inferior biocompatibility and surface characteristics[4],[5].

According to published research[4], titanium and zirconium are the only two metals commonly used in implantology that do not inhibit the growth of osteoblasts, the bone forming cells that are essential for osseointegration. In addition to this attribute, Roxolid can be combined with Straumann's third-generation SLActive surface technology, unlike other alloys such as TAV, which cannot accommodate the sophisticated mircostructuring processes required.

SLActive outperforms main competitor

In addition to material, surface is a key factor in successful implant therapy. In 2005, Straumann introduced its third generation implant surface technology SLActive, which cut implant healing times in half from 6-8 to 3-4 weeks[6].

In a preclinical head-to-head study presented at the EAO, the osseointegration of titanium-SLActive was compared to a leading competitor surface (TiUnite®[7]) at three time points (10 days, 3 and 6 weeks) after implant placement[2]. At each time, SLActive demonstrated higher mean shear strength values (indicative of surface osseointegration), which were statistically significant at both 3 and 6 weeks. The investigators concluded that SLActive was more effective in enhancing interfacial shear strength. This adds to the large body of data and experience supporting SLActive on titanium implants as the benchmark.

A new level of osseointegration indicated

One of the most remarkable findings presented at the EAO was the observation that Roxolid enhanced osseointegration beyond the current SLActive gold standard. In a preclinical study, titanium-SLActive implants were compared with Roxolid-SLActive equivalents at 4 weeks after placement. Histomorphometry revealed significantly more bone growth around the Roxolid implant. The removal torque values for the new material were significantly higher, leading to the conclusion that Roxolid improved osseointegration performance[2].

Initial results from large clinical program

In a prospective pilot clinical trial, which is still ongoing, small diameter (3.3mm) Roxolid implants were placed in 22 patients. Preliminary data (6-12 months) were presented at the EAO showing very promising survival rates. This is the first of a number of clinical studies evaluating the new material. A multicenter double-blind randomized study is underway in 8 European centers with 88 patients and the planning phase of a non-interventional study involving more than 300 patients in Europe and North America has been completed.

In the future, safe, high strength, small diameter implants with enhanced osseointegration properties are expected to offer a number of advantages to dental professionals and patients. These include: enhanced esthetics, shorter healing times and the possibility of avoiding bone graft/augmentation procedures in patients with narrow bone ridges, which in turn will translate into simpler and less traumatic treatments and reduced chair time.

References

[1] Based on internal specifications and ASTM F67
[2] Gottlow J et al. Preclinical data presented at the 23rd Annual meeting of the Academy of Osseointegration (AO), Boston, February 2008, and at the 17th Annual Scientific Meeting of the European Association for Osseointegration (EAO), Warsaw, September 2008
[3] Barter S et al. Clinical data presented at the 17th Annual Scientific Meeting of the European Association for Osseointegration (EAO), Warsaw, September 2008
[4] Steinemann S. Peridontol 2000 1998;17:7-21
[5] Wong M. et al. J. Biomed Mater Res 1995;29:1567-1575
[6] Oates TW et al. Int J Oral Maxillofax Implants 2007;22:755-760
[7] Registered trademark of Nobel Biocare

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