|Year : 2022 | Volume
| Issue : 3 | Page : 206-210
Prospect of Zirconium as a Dental Implant: A Comprehensive Review
Sarfaraj Ansary1, Sajed Ali Molla2, Ziyauddin Seikh1, Shamim Haidar1
1 Department of Mechanical Engineering, Aliah University, Kolkata, West Bengal, India
2 Department of Oral and Maxillofacial Surgery, Dr. R Ahmed Dental College and Hospital, Kolkata, West Bengal, India
|Date of Submission||17-Apr-2022|
|Date of Decision||27-Jun-2022|
|Date of Acceptance||13-Jul-2022|
|Date of Web Publication||14-Nov-2022|
Department of Mechanical Engineering, Aliah University, Kolkata - 700 156, West Bengal
Source of Support: None, Conflict of Interest: None
Titanium and its alloys are satisfying the demand of dental implant industry for a long. Due to the problems of titanium implants, such as corrosion, ion radiation to the human body, cytotoxicity, and possible esthetic limitations, researchers are always looking for novel implant materials. Recently, zirconia implants as a substitute of titanium implants are becoming popular in the implant sector because of its improved biocompatibility, low plaque affinity, and desirable mechanical properties. However, there are very few clinical studies available for its long-term success rate. The purpose of the study is to summarize and analyze the current data accessible for zirconia implants with respect to its different mechanical properties and clinical survival rates. The available information suggests that a zirconia implant might be considered as a good alternative of titanium in the dentistry industry. It also shows good biocompatibility, better mechanical property, and esthetically a better choice of the implant compared to titanium implants.
Keywords: Dental implant, esthetics, implant materials, osseointegration, zirconia implant
|How to cite this article:|
Ansary S, Molla SA, Seikh Z, Haidar S. Prospect of Zirconium as a Dental Implant: A Comprehensive Review. J Dent Res Rev 2022;9:206-10
|How to cite this URL:|
Ansary S, Molla SA, Seikh Z, Haidar S. Prospect of Zirconium as a Dental Implant: A Comprehensive Review. J Dent Res Rev [serial online] 2022 [cited 2023 Jan 30];9:206-10. Available from: https://www.jdrr.org/text.asp?2022/9/3/206/361138
| Introduction|| |
Due to its outstanding biocompatibility and mechanical characteristics, commercially pure titanium (Ti) has long been the preferred material for dental implants., In addition, the metallic hue of Ti can give rise to esthetic issues., As a response, implant research has centered on developing implant material that is tooth colored and improves the cosmetic appearance of dental implants while also being extremely biocompatible and capable of withstanding the stresses present in the oral cavity. Aluminum oxide is a ceramic substance that has been utilized for dental implants.,,, It osseointegrated successfully; however, due to its dismal survival rate, it was taken off the market.,,, Electrizing side effects are also noticed in the case of the metallic implant (Ti-alloys) as it reacts with the aqueous fluid of the oral cavity. Metal ions are regularly released into the oral cavity by titanium implants. These ions have the potential to interact with other biomolecules, causing hypersensitivity and autoimmune disease. As a result, increasing the rate of corrosion raises the risk of causing immunologic or toxic responses.,, Due to these limitations, new ceramic implant technologies are being developed. Ceramics, on the other hand, are vulnerable to tensile and shear strain, and surface defects can lead to premature cracking. Such circumstances imply a greater probability of fracture. Ceramics made with Zr having high strength have recently gained popularity as novel dental implant materials. In comparison to metallic implants, Zr-ceramics relatively release a very little amount of ion. Due to their superior flexural strength and fracture resilience, yttrium-stabilized tetragonal zirconia polycrystals seem to outperform aluminum oxide for dental implants.,,
The surface morphology and material properties of a biomaterial are important in osseointegration. Implant surface morphology is one important characteristic that impacts in wound recovery at the implantation site; according to AlBrektson et al., many physical and chemical surface changes have been devised to aid osseous healing. Application of bioactive coatings and micro-roughness optimization are two significant ways for enhancing surface characteristics. Clinical application of zirconia dental implants is limited as surface modifications are difficult to fabricate, and flawless surfaces of implanted parts are not suitable for osseointegration as it creates weak tissue contact.
Even though Zr may be used as implant material, its nanoparticles are employed as coating on titanium implants too. To promote osseointegration, sandblasting with circular zirconia granules may be used as a different kind of surface treatment for titanium implants.,,,, Zirconia looks to be a great material for dental implants because of its mechanical advantages and tooth-like color. Aside from that, a few mechanical and chemical difficulties have been observed. The material does not function well in lower temperature or humid conditions, which is a major drawback of zirconia dental implants. When exposed to cold temperatures over extended periods of time, the material gradually changes its shape and resilience.,,,
Mechanical damages may happen during the implant's surgical implantation or after it has been functionally loaded. All locations of significant stress concentration should be avoided due to the fragile nature of ceramics, which encompasses, but is not restricted to, thread layout variations. Keen, thick, and slender threads, also in interior line angles that are sharp, are locations of stress concentration that might increase the probability of implant failure.
| Mechanical Properties of Zirconium|| |
The hardness of commercial yttria-stabilized zirconia is 1200 HV, density is near about 6.05 g/cm3, bend strength varies from 900 to 1200 MPa, compressive strength is 2000 MPa, Young's modulus is 210GPa, fracture toughness is 7–10 MPam1/2, and thermal expansion coefficient is 11 × 10−6 1/K. There are three main organizational patterns for zirconia: monoclinic (M), tetragonal (T), and cubic ©. At room temperature, pure zirconia is monoclinic and stable up to 1170°C. Above this degree, it changes into the tetragonal phase, then into the cubic phase which lasts until the melting temperature at 2370°C. The tetragonal phase returns to monoclinic upon cooling at temperatures between 100°C and 1070°C.
| Corrosion Resistance|| |
The primary mechanism of aqueous corrosion in the case of dental implants is the ion releasing process, in which hydronium ions replace alkali ions of material from the solution. Yttria Stabilized Zirconia (Y-TZP) ceramics have a nearly complete tetragonal microstructure with very tiny grain sizes (<1 μm) and excellent chemical stability. When exposed to a corrosive environment, the alkali ions are immobilized, giving it outstanding corrosion and wear resistance. In an in vitro study by Milleding, with the presence of a solution of 4% aqueous acetic acid at 80°C temperature for 18 h and small changes on the Zr-implant surface have been recorded. It is possible that zirconia's better corrosion resistance is related to the existence of crystalline phases which are less susceptible to acid attack than the glass phase.
| Biocompatibility|| |
Zirconia ceramics are chemically inert materials that have no erythrogenic, allergic, immunological, or toxic effects in connective tissues.,,, Sterner et al. discovered Ti and alumina particles strongly induce tumor necrosis factor-α inflammatory signal whereas zirconia had no impact on the human monocytic cell line. There were no local or systemic harmful effects when yttria-stabilized zirconia was implanted in animal bones. Christel implanted zirconia (Y-TZP) and alumina pins inside rabbit femurs and found no difference in bone reactivity to the implants. Many in vitro and in vivo studies proved improved biocompatibility of pure Y-TZP, which is completely free of radioactive materials.
| Esthetic Result|| |
Dental implants constructed of zirconia are the potential substitute of titanium dental implants, according to Blaschke and Volz., Zirconia dental implants not only provide good esthetic benefits but also offer greater osseointegration and soft-tissue response than that of titanium implants. Due to its tooth-like hue, implants with zirconia have the ability to solve the cosmetic constraints associated with Ti-implants. Under thin mucosa, zirconia implants cause less color change, according to spectrophotometer analysis., Crowns made from zirconia are more popular, and they do have certain benefits such as strength, tooth-like color, durability, and good biocompatibility than other materials. As per our clinical crown therapy, we found zirconia crown fittings require less tooth reduction. [Figure 1] shows the tooth-like color of zirconia crown.
|Figure 1: Clinical image of zirconia crowning of two patients (a) before crowning of patient 1 (b) during crowning of patient 1 (c) after crowning of patient 1 (d) after crowning of patient 2|
Click here to view
| Osseointegration|| |
Several studies have been conducted comparing the osseointegration of zirconia to titanium implants. The majority of studies concluded with less significant differences in the osseointegration effect between zirconia and titanium implants.,, Depprich et al. discovered a comparable adhesion of both implants to bone, as well as very structurally similar characteristics. Although titanium implants have a stronger primary cell adhesion and attachment, there was a greater proliferation of osteoblasts surrounding zirconia implants. Zirconia has a greater bone-implant contact than titanium, according to Schultze-Mosgau et al.,48],49],, and Dubruille et al. Gahlert et al. found that submerged zirconia implants had higher peri-implant bone volume densities than Ti-implants. [Table 1].
| Conclusion|| |
Based on the literature study, this article seeks to summarize the present scientific state of zirconia dental implants. Implant systems made of zirconia are a novel addition to dental implants and they might eventually replace titanium as a viable option, with greater soft-tissue bonding, esthetic and better biocompatibility as well as equivalent osseointegration. Further long-term, randomized trials in the clinic are required to justify the use of Zr-implants in ordinary clinical practice. Zirconia implants have a promising future as novel processing technologies (Powder metallurgy) and purifying processes are being developed.
The author would like to acknowledge the support of DST, Ministry of Science and Technology (Government of India) to carry out research work in the field of metallurgy on the topics of implant materials.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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