“Many have tried; few have succeeded” is a saying that certainly rings true in the case of Prof. Ervin Weiss from Israel. Several years after he graduated from den-tal school in his home country, he relocated to the US, where he worked at the National Institutes of Health for three years and trained to become a microbiologist. Back

“This is the first restorative material in dentistry that treats a disease while  restoring function, aesthetics and phonetics,”— Prof. Weiss said when  speaking about Nobio’s goals for Infi nix.

in Israel, he became a lecturer in restorative dentistry, finding his calling in teaching and mentoring the next generation of dental professionals. However, this is not Prof. Weiss’s only passion. The combination of his scientific background and sheer endless curiosity led him to reflect on the lack of efficiency of traditional restorative dental composites and their high failure rate. He sought to find an antimicrobial material with permanently integrated activity, but none had been developed, and he was continually told that such a product was an im-possibility. Driven by this unsatisfactory answer and his idea, what started as a mission to find a solution to this problem became his legacy: the world’s first antimicrobial composite—and it might change dentistry forever.

That dental composites have many shortcomings is a well-known and scientifically backed fact. Indeed, it was shown by Mjör in 2005 and Kopperud et al. in 2012 that up to two-thirds of all restorative dental treatments involve the replacement of failed restorations because they are more prone to recurrent decay (due to the microleakage that results from shrinkage on polymerisation), debonding, technique sensitivity and the degradation of resin by oral bacteria. As reported in a market analysis published by Grand View Research, in the US alone, 200 million cavities are treated every year, and that means about 133 million dental fillings that will fail.

In an interview with Dental Tribune International (DTI), Prof. Weiss stressed that preventive oral healthcare is the only answer to addressing oral disease, and restorative care cannot do so; however, restorative treatment is a necessity at times. This is where Prof. Weiss and his com-pany Nobio come in, offering a technology that “trans-forms materials, products and surfaces to antimicrobial, with its revolutionary particles, providing strong, safe and durable bio-protection, for life”.

Fig. 1: The control composite (top) shows bacterial growth after 1 hour and a thick biofilm after 24 hours. The antibacterial filler (bottom) shows broken down bacteria after 1 hour and no live bacteria on the surface after 24 hours, respectively. (All images: © Nobio)

How it works 

In essence, Nobio’s quaternary ammonium silica (QASi) particles exert concentrated electrostatic stress on bac-teria that come in direct contact with the restorative

“Now, instead of  acting as surgeons and just  cutting away the disease and  restoring what is left as  technicians, dentists can treat the disease itself, much like any other medical  treatment.”

material, causing their death, Prof. Weiss explained. “When bacteria touch the nanoparticles incorporated into the surface of the composite, the bacteria explode and die. This way, the acidity in the oral cavity is reduced and teeth cannot demineralise,” he continued. 

By killing these bacteria, which would usually promote demineralisation and subsequent carious lesions, Infinix composites reduce this mineral loss, preserving the restoration over time. Nobio’s Infinix family of compos-ite products are the first to be cleared by the U.S. Food and Drug Administration (FDA) for reducing tooth decay. In clinical trials, the antibacterial composites significantly reduced tooth demineralisation.

Laboratory studies have shown that the QASi particles are potent antibacterial agents, do not leach out, inhibit the breakdown of the composite and maintain their antibacterial activity. Infinix composites were the only composites to maintain neutral pH in the presence of oral bacteria and sugar in a comparison with three conven-tional, widely used composites.6

The range consists of four products. For an antibacterial cavity cleansing effect, Infinix Universal Bond is a general-purpose, light-polymerised, self-etching bond-ing system (prime and bond). It provides strong adhesion between enamel, dentine and all types of restorative materials. Infinix Flowable Composite is a single-step, light-polymerised, low-viscosity flowable composite. It can be used for Class III and V restorations, ideally as a base and liner in direct restorations, as well as a pit and fissure sealant. Infinix Bulk-Fill Flow Composite is a low-viscosity composite with a high depth of polymerisation. It is ideal for posterior restorations, which are more prone to recurrent caries. Infinix Universal Com-posite is a light-polymerised, high-viscosity universal restorative composite which performs across a variety of conditions.

Fig. 2: A detailed illustration of Nobio’s quaternary ammonium silica technology demonstrates how the material works in the oral cavity.

Clinical study confirms efficiency

From 2019 to 2020, the University of California, San Francisco (UCSF) in the US collaborated with Nobio in a clinical trial that tested the antibacterial composite in 25 patients who wore mandibular partial dentures with acrylic flanges on both sides of the mouth.7 The research-ers recessed a human enamel slab and a composite separated by a tiny gap into the flanges, employing Infinix in one flange and a standard composite as a control in the other. The participants were not aware of which side of the denture contained which composite. This gap model simulated a faulty tooth–restoration interface and then exposed it to cariogenic challenge.

After a four-week wearing period, samples were as-sessed in the laboratory using cross-sectional micro-hardness testing of the enamel. The UCSF researchers found that the average mineral loss for the Nobio side was significantly lower (nearly 70%) than for the control side in every patient.

Fig. 3: The in situ denture models show the enamel and composite slabs which were used in the University of California, San Francisco clinical trial.

Welcome to the future

In late summer 2020, the start-up, which Prof. Weiss founded in 2015 with Dr Julia Rothman, received FDA clearance to commercially distribute Infinix. Reporting on this achievement, local online newspaper the Times of Israel concluded that the clearance “gives Nobio access  to the [US] $1.4 billion dental materials market”.

In his interview with DTI, Prof. Weiss said that the  COVID-19 pandemic had changed the original roll-out plans for the products. Infinix was to have been made available at the end of 2020 in Israel and the US, but that was changed to spring 2021. In the meantime, free prod-uct samples have been distributed to many practising key opinion leaders around the world, and according to Prof. Weiss, the feedback has been very positive so far.

Perhaps, it is rather paradoxical to ask Prof. Weiss where he thinks the future of dental materials is heading, since it seems that he and his team have just set a new gold stan-dard, but for him, the vision is very clear: “We want every possible material to be equipped with Nobio technology so that patients can benefit from this new generation of mate-rials that can shift the balance towards remineralisation and health.” Indeed, Prof. Weiss confirmed that the company is already working on core build-up materials used in root canal  therapy. Orthodontic cements and PMMA-based resins for partial and complete dentures are next on the agenda.