Titanium as implant material has already been used in dentistry for several decades. However, its use for dental restorations has been limited due to several reasons, but primarily due to difficulties related to its fabrication. 3D printing combined with anodization opens up new prospects for the application of titanium restorations.

Traditionally, titanium restorations were produced by casting. However, proper fabrication of titanium restorations by casting requires a higher level of technical competence, as well as more expensive equipment and supplies compared to the ones made from CoCr (Cobal-Chrome). Lack of appropriate competence, equipment, and supplies might result to quality problems. Such problems could be overcome by producing restorations by CNC milling instead of casting, which increases cost.

In parallel, expectations of patients have also continuously increased, especially in the field of esthetics. Nowadays, patients prefer whiter and more natural-looking teeth, therefore the use of gray-colored metal structures (like that of Ti and CoCr) is no longer ideal by everyone. These led to limited use of titanium restorations vis-à-vis CoCr ones (with the exemption of implants and abutments which are not produced from CoCr) and from esthetic reasons vis-à-vis the even more expensive zirconia.

In the last decade, there have been substantial developments in dentistry, led by 3D printing.  3D printing generated a revolution and – among others – made possible reliable mass production of titanium restorations. Application of the technology results in higher quality compared to casting, and lower price compared to milling.

These advantageous features of titanium and 3D printing make titanium a ‘competitive’ alternative to restorations made of CoCr, as well as prosthodontic restorations made by casting and milling technologies.

In addition, the increasing esthetic issues associated with titanium may be relatively easily overcome by a technology called anodization.

The anodization of titanium is a well-known and well-established technology in dentistry and in the medical world. It has been used extensively for color-coding helping visual identification.

Titanium anodization is an electrolytic passivation process that increases the oxide layer on the surface of the titanium. The generated oxide layer gives the perception of color due to an interference phenomenon, similar to a prism. The final perceived color depends on the thickness of the oxide layer. Since anodizing does not require the use of dyes, the oxide layer is biocompatible.

The results of different publications and our experiments demonstrate that anodization can be used successfully in order to improve esthetics by reducing greyness. Furthermore, recent studies show that anodization can be effectively applied to increase osseointegration and therefore functionality of titanium restorations.

In the following part, a few examples are presented, covering both color esthetics and functionality.

Titanium implant bar

Implant bars make part of removable bridges. Such a bridge is regularly removed by the patient in order to clean it. After removal of the bridge, the bar becomes visible for the patient (and eventually even for others). If the bar is anodized (e.g. to rose gold hue) it is in better harmony with the color of the interior of the mouths than a non-colored grey one. In this way, the bar better fits its environment and therefore result to an increased esthetic for the patient.

Titanium framework of removable partial denture

Metal framework removable partial dentures are the most common type of partials. They consist of a metal framework (generally CoCr) that contains artificial teeth set in an acrylic resin. Patients can remove and reinsert them when required without professional help. During these operations, patients are faced with the grey color of the metal framework. In addition, in the case of an upper partial, the grey colored framework might be visible by others. Application of 3D printed titanium frameworks anodized to the color of the palate might decrease esthetic concerns. As a result, the framework gets hidden in the mouth, in addition, it gives a more esthetic view when the partial is removed.

Abutment

Abutments are made of titanium and delivered generally in the natural grey color. However, the grey color of the titanium abutment can be seen through the soft tissue or translucent restorative material. It has been demonstrated by several authors that anodization can be used optimizing the final esthetics. The colored abutment is more easily masked than the non-colored one making it an advantageous option for anterior cases and for patients with thin-tissue biotypes.  

Patient-Specific Implants

In the case of patient-specific implants – contrary to the previous examples – anodization can be applied for functional rather than for esthetic reasons. Anodization of dental implants was the subject of several studies. Some interesting conclusions were as follows: The amount of bone-to-implant contact (BIC) is an important determinant in osseointegration, and therefore in the long-term success of dental implants. The osseointegration rate of titanium dental implants is related to their composition and surface roughness. Titanium anodized surface significantly increases blood clot retention, significantly increases nano-roughness, and favors osseointegration. These conclusions highlight the functionality of the anodized titanium surfaces, as well as the potential of anodization of dental implants, including supraosteal implants.

Conclusions

Anodized 3D printed titanium restorations might be a relevant option to increase esthetics and functionality of dental restorations. Concerning esthetics first impressions and feedbacks by our dentists and their patients on the anodized titanium restorations are positive. Concerning functionality results of the published studies are promising and encourages further investigations.

I express my thanks to our strategic partner, the Dent-Art-Technik dental laboratory for their contribution to this article.

About The Author:

Zsolt Pásztor is very engaged in the application of 3D printing in the healthcare sector. He is the Managing Director of Premet (www.premet.hu), a company focusing on the production of 3D printed products, including those made of CoCr, titanium and PEEK, for the dental and medical sectors. He is the leader of a3D Printing Training Centre that delivers training on digital dentistry. Zsolt is the founder and Vice-President of the Hungarian Additive Technology Association.

He is the lead expert of a project aiming at facilitating transnational cooperation of Hungarian entities on the application of 3D printing in the health sector. He is very much interested in importing best practices to Hungary and in a broader sense to the Central and Eastern European region and export them from the Region. Zsolt is also the current 3DHEALS Budapest community manager. Dr. Pásztor will be speaking at 3DHEALS2020 CMF panel as well as updating the Hungarian 3D printing ecosystem.

Related Articles:

Metal 3D Printing in Dentistry – Restoration

Interview with Dr. Mayra Vasques, Dental 3D Printing, INNOV3D

Interview: Game Changer with 3D Printed Dental Implants (Video)

3D Printing Has Come of Age But How Safe Are the Devices Going Into Our Mouth?

What Matters When Enabling Your Dental Practice with 3D Printing and 3D Scanning

The post From Esthetic to Functionality – Perspectives of Anodized 3D Printed Titanium Dental Restorations appeared first on 3DHeals.

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Based on the trends of the last few years, it can be stated that the digital revolution in dentistry has begun and seems to be irreversible. The question is no longer whether it should be introduced, but when, at what rate and to what extent. 

3D printing, and more specifically metal 3D printing, has a key role in this process.

According to forecasts, the world of dentistry will be profoundly transformed by digital dentistry technologies. Experts agree that in the coming years, changes will be driven and impacted the most by 3D printing (additive manufacturing).

3D printing has made a spectacular entry and given a new impetus to the spreading of digital dentistry. Two areas can be mentioned, where the technology is already widely applied and its impact has been significant: 1) the manufacture of invisible orthodontic aligners and 2) metal restorations. This article gives an overview of the latter, based primarily upon the experience gained in Central-Eastern Europe.

Nowadays, typically CoCr restorations are produced by 3D printing in dentistry. At the same time, titanium restorations gain also ground, the share of which is expected to grow by a significant rate in the coming years. 3D printed titanium restorations – owing to the advantageous features of titanium and 3D printing – offer a competitive alternative to restorations made of CoCr and zirconia, as well as restorations made by casting and milling technologies.

Casting is the longest used and most widely spread technology in dentistry. Both CoCr and titanium products can be fabricated by casting. As casting of titanium requires a higher level of technical competence and is also more expensive, with the exception of special works, the prosthetic restorations are typically made of CoCr.

The advantage of casting is its low investment cost, and in line with this the low price of the final product. However, some of the restorations produced by casting (about 10 to 20%), due to the features of the technology, contains inhomogeneity and inclusions. As these products are faulty, they must (should) be fabricated again.

The alternative to casting has been CNC milling for about two decades. CNC milling opened up the way to using new materials in addition to CoCr and titanium, too. A material frequently used for such prosthodontic restorations is zirconia. Zirconia restorations, for the time being, can only be produced with this technology. Moreover milling of zirconia requires a milling machine of lower capacity than that of CoCr or titanium.

One of the great advantages of the milling technology is that it produces a homogenous structure, reducing the ratio of the structurally faulty products practically to zero. An additional important advantage of the technology is that it results in a smooth surface, which is an indispensable requirement at the parts of the restorations fitting to the implants or implant interfaces (referring to as fitting parts later). A drawback of CNC milling is the high price of the product, which is resulted from the high investment costs and the high quantity of raw material (disk) to be used that finally turns into waste to a great extent.

As a result, CNC milling is used primarily for the production of zirconia, and to a smaller extent of CoCr and titanium restorations.

Metal 3D printing offers a new, viable option over casting and CNC milling. 3D printing is suitable for the production of both CoCr and titanium restorations. This latter, due to the explosive nature of titanium-oxide, requires a printer with a working chamber expressly engineered for this purpose, as well as greater technological competence and discipline. (It might be a reason of the current less extensive use of titanium vis-à-vis CoCr).

The product obtained by 3D printing, similarly to milling, has a homogeneous structure, therefore, the proportion of the faulty products is practically zero, too.

The surface of the product is rougher than that of the product made by milling, at the same time – with the exception of the fitting parts – this roughness is acceptable, since in case of veneering with ceramics it can be compensated, and in case of veneering with composites it is even advantageous.

Thanks to the recently developed processes combining 3D printing and milling (e.g. sint&mill), the fitting parts can also be produced in the required quality. Owing to this process, the smoothness of the fitting parts is equivalent to that obtained by CNC milling (as it is made by CNC milling), at the same time, the overall cost of production will be lower than in case of milling.

While the initial investment cost in case of 3D printing is also high, the significantly smaller amount of raw material (powder) required and the higher productivity result in lower specific fabrication costs and, consequently, a favourable product price when compared to milling.

In case of CoCr, the price of the 3D printed products is already competitive with that of the cast items, whereas their quality is higher. Due to the competitive price, 3D printing increasingly replaces casting and CNC milling in some Central-Eastern European countries. What is more, there are several dental labs in the region which produce restorations exclusively by 3D printing.

3D printing opened up new prospects for the fabrication and application of titanium restorations. The use of technology leads to higher quality compared to casting, a lower price compared to milling and greater conformity of the digital model and product compared to both. The advantage of 3D printing over milling is manifest particularly in the case of the various implants (e.g. circular, symmetric traditional or one-off platforms resting on the cortical bone surface) and traumatic platforms, as printing allows the production of such forms, which are practically impossible to make by milling.

Using titanium improves the sense of comfort, as well as extends the lifecycle of the restoration, with the patient being the ultimate winner. The weight of the restorations made of titanium is lower than those made of zirconia and particularly of CoCr (one half of this latter), and their tensile strength and elasticity features are much closer to those of the natural bone. An additional argument in favour of using titanium is its good osseointegration property, which is an important criterion in case of implants, whereas its biocompatibility is preferred in case of sensitivity to traditional metal restorations.

The increasing reputation of 3D printing generated by the positive experience gained so far, as well as the declining prices of 3D printers and raw materials are suggesting the more and more widespread application of 3D printed metal restorations. This is particularly true for titanium restorations, which can also be applied in cases when the use of CoCr is not recommended or not possible.

Those practitioners, who have not yet done so, should try the application of 3D printed metal restorations. To do so, it is not necessary to invest in an own 3D metal printer since there are several service providers and centre on the market which can print these restorations, and naturally we are also pleased to help in respect to both CoCr and titanium restorations.

I express my thanks to my colleague, Mr. Lajos Bozsányi, for this contribution to this article.

About the Author:

Zsolt is strongly engaged in the application of 3D printing in the healthcare sector. He is the Managing Director of Premet (www.premet.hu), a company focusing on the production of 3D printed products, including those made of CoCr, titanium and PEEK, for the dental and medical sectors. He is the leader of a3D Printing Training Centre that delivers a training on digital dentistry. Zsolt is founder and Vice-President of the Hungarian Additive Technology Association. He is the lead expert of a project aiming at facilitating transnational cooperation of Hungarian entities on the application of 3D printing in the health sector. He is very much interested in importing best practices to Hungary and in a broader sense to the Central and Eastern European region and export them from the Region. Zsolt is also the current 3DHEALS Budapest community manager.

Related Articles:

Where does power lie in the 3D printing medical industry? A rundown of Porter’s Five Forces

What Matters When Enabling Your Dental Practice with 3D Printing and 3D Scanning

3D Printing in Dentistry: From a Broken Tooth to Digital Revolution

The post Metal 3D Printing in Dentistry – Restoration appeared first on 3DHeals.