Dental implants: Titanium vs. zirconia – Mr. Matthieu DupuiFeatured Products Promotional Features
Posted by: The Probe 10th November 2018
Practitioners rely on dental implant materials that are mechanically strong and biocompatible, as well as being resistant to both corrosion and fracturing. Commercially pure titanium (cp-Ti) and titanium alloys are often regarded as “gold standard” materials for fabricating dental implants.
Commercially pure titanium typically contains trace elements of iron, nitrogen, oxygen and carbon, which improve the implant’s mechanical qualities.[i]Similarly, the most common titanium alloy consists of 6% aluminium and 4% vanadium (Ti-6Al-4V), which is then heat treated to improve its strength – resulting in a low-density material that is highly resistant to corrosion and fatigue. With a low modulus of elasticity that is similar to that of bone, titanium offers favourable stress distribution at the bone-implant interface, enabling it to withstand the pressures of occlusal forces.[ii],[iii]
The vast majority of dental implants are made of titanium, as it is a reliable material with a proven long-term survival rate of 99.7% in many cases.[iv]In recent years, however, there have been some concerns over potentially immunologic and aesthetic issues surrounding titanium implants. For instance, it has been observed that an allergy to titanium is more likely in patients who are sensitive to other metals – it is estimated that up to 17% of women and 3% of men are allergic to nickel, as well as cobalt and chromium.[v]
While allergies to titanium are rare, they are not beyond the realm of possibility. Any allergic reaction to titanium is a result of the presence of ions in the human body following ingestion, as well as skin or mucosal contact with the metal. When these ions bind with native proteins, they act as allergens to cause hypersensitivity and can become concentrated within human tissues and regional lymph nodes.[vi]Titanium ions or micro-particles released in the area of periodontal tissues adjacent to an implant can cause an inflammatory reaction, which ultimately jeopardises the success of the implant.[vii]
Besides the risk of hypersensitivity to titanium and its alloys, there are also aesthetic challenges to contend with. The dark, greyish colour of titanium implant components can become visible through the gingiva, especially for patients with a thin gingival biotype. This issue is exacerbated further in cases where the gingiva recedes, or there are unfavourable soft tissue conditions that can compromise the overall desired aesthetic.[viii]
Some patients are now seeking metal-free implant solutions, in order to avoid the issues associated with titanium. As a result, zirconia is becoming a popular material of choice in implant fabrication. With close similarities to diamond, zirconia offers almost the same biocompatibility and mechanical strength as titanium. Results from one study demonstrate that zirconia generates effective adhesion and proliferation of fibroblast and osteoblast cells, which encourages osseointegration and epithelial healing post-implant placement.[ix]Due to its tooth-like colour, zirconia is a material that can provide superior aesthetics, especially when placed in the anterior region where aesthetic outcomes are of particular concern. Zirconia also has a low affinity to bacterial plaque, which, as practitioners are aware, can cause diseases such as peri-implantitis.[x]
Although it has its advantages, zirconia does have its limitations as a dental implant material. Often manufactured as a one-piece component, for example, zirconia leaves little room for errors, as the prosthesis can only be fitted with cement – any leakage increases the risk of a bacterial infection. Moreover, implants should be surgically placed within ideal bone volume and density, at the correct location and angle. Where bone is less than optimal, however, practitioners might prefer to place a titanium implant and carry out a bone graft at the same time – a procedure that carries more risk with a zirconia implant. While it is a strong material against compressive forces, zirconia is also not as “flexible” as titanium and can be prone to fracture.[xi]Additional research is still needed in order to determine the long-term predictability of zirconia, which has only been used in implantology for a relatively short period of time.
While titanium and zirconia have their own merits, it might be difficult for clinicians to decide which material is best in order to guarantee superior results for implant patients. The most effective implant systems take advantage of the properties in both titanium and zirconia. TBR’s Z1 implant, for example, combines a titanium body with a zirconia collar in one seamless component. Clinical studies have proven the efficacy of this implant, which promotes supreme bone and soft tissue healing, thereby enhancing the overall visual result.ix
While dental implants are predominantly fabricated from titanium, it is evident that zirconia components offer various advantages when used in the right clinical situation. Ultimately, it is up to the practitioner to choose an implant system that ensures optimal function and aesthetics for each patient.
[i]Kirmanidou, Y., Sidira, M., Drosou, M.E., Bennani, V., Bakopoulou, A., Tsouknidas, A., Michailidis, N. and Michalakis, K. (2016) New Ti-Alloys and Surface Modifications to Improve the Mechanical Properties and the Biological Response to Orthopedic and Dental Implants: A Review. Biomed Res Int. 2908570. Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4738729/. [Last accessed: 16.04.18].
[ii]Greger, M., Widomská, M. and Snášel, V. (2012) Structure and properties of dental implants. Link: http://metal2012.tanger.cz/files/proceedings/02/reports/409.pdf. [Last accessed: 16.04.18].
[iii]Osman, R. B. and Swain, M. V. (2015) A Critical Review of Dental Implant Materials with an Emphasis on Titanium versus Zirconia. Materials. 8:932-958. Link: https://pdfs.semanticscholar.org/eeac/6a042e7f43212764effd8ac3cc2d53561a77.pdf. [Last accessed: 16.04.18].
[iv]Shin, S.-I., Yun, J.-H., Kim, S.-G., Park, B., Herr, Y. and Chung, J.-H. (2014) Survival of 352 titanium implants placed in 181 patients: a 4-year multicentre field study. Journal of Periodontal and Implant Science. 44(1):8-12. Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3945397/. [Last accessed: 16.04.18].
[v]Bocca, B. and Forte, G. (2009) The Epidemiology of Contact Allergy to Metals in the General Population: Prevalence and New Evidences. The Open Chemical and Biomedical Methods Journal. 2:26-34. Link: https://www.researchgate.net/publication/228368359_The_Epidemiology_of_Contact_Allergy_to_Metals_in_the_General_Population_Prevalence_and_New_Evidences. [Last accessed: 16.04.18].
[vi]Chaturvedi, T.P. (2013) Allergy related to dental implant and its clinical significance. Clin Cosmet Investig Dent. 5:57-61. Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3753052/#b33-ccide-5-057. [Last accessed: 16.04.18].
[vii]Peterson, R. C. (2015) Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite. Metals (Basel). 4(4):529-569. Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4307950/. [Last accessed: 16.04.18].
[viii]Gupta, S. (2016) A Recent Updates on Zirconia Implants: A Literature Review. Dent Implants Dentures. 1:113. Link: https://www.omicsonline.org/open-access/a-recent-updates-on-zirconia-implants-a-literature-review-.php?aid=82588. [Last accessed: 16.04.18].
[ix]Bianchi, A. & Bosetti, Michela & Dolci, G & T Sberna, M & Sanfilippo, S & Cannas, Mario. (2004) In vitro and in vivo follow-up of titanium transmucosal implants with a zirconia collar. Journal of applied biomaterials & biomechanics. 2:143-50. Link: https://www.researchgate.net/publication/46037726_In_vitro_and_in_vivo_follow-up_of_titanium_transmucosal_implants_with_a_zirconia_collar. [Last accessed: 16.04.18].
[x]Patil, R. (2015) Zirconia versus titanium dental implants: A systematic review. Journal of Dental Implants. 5(1):39-42. Link: http://www.jdionline.org/article.asp?issn=0974-6781;year=2015;volume=5;issue=1;spage=39;epage=42;aulast=Patil#ft6. [Last accessed: 16.04.18].
[xi]Cionca, N., Hashim, D. and Mombelli, A. (2016) Zirconia dental implants: where are we now, and where are we heading? Periodontology 2000. 73(1):241-258. Link:https://onlinelibrary.wiley.com/doi/full/10.1111/prd.12180. [Last accessed: 16.04.18].