Nanos and dental care

Nanos and dental care

By the AVICENN team – Last added July 2022

What nanomaterials can be found in dental products?

In the field of dentistry as in other fields, it is difficult to distinguish today between “promises” still in the research & development stage and nano applications that are actually commercialized. Nanoparticles have been used in dental composites for decades.

In France, the 2017 R-Nano report card counts three “entities” (companies) that reported nano for “manufacture of instruments and supplies for medical and dental use.”
It allows the identification of several substances declared in nanoparticulate form as being used in the manufacture of “dental products” (or “for dental use”): aluminum oxide, iron oxide, silica (without however providing further details on the manufacturers or the type of products, properties or quantity of the registered nano substances).

According to Gardon-Mollard, Ph.D., a doctor of Dental Surgery, nanoparticlesWho‘s¹Afraid of Dental Material Toxicity, The Dentalist, October 2019:

• in sealing cements (zinc oxyphosphates, CVIMAR…)
• in calcium silicates (Biodentine)
• in impression materials (elastomers)
• in composites and adhesives, dispersed mainly during polishing operations if these are carried out without spray or vacuum.
  
  

What is known about the associated risks?

Routes of exposure and risks

Few “general public” resources on the risks specifically related to nanoparticles in dental products are available online.

According to the professionals, the nanoparticles are confined in a resin that, once hardened, prevents the nanoparticles from coming off. Only a very small number of nanoparticles would be likely to be ingested as a result of wear or abrasion of products – but in much smaller proportions than those fromfood or toothpaste, lipsticks and lip balms, etc.

But what is true for the consumer is less true for professionals: as the European Agency for Safety and Health at Work points out, ” Milling, drilling, grinding and polishing of applied medical materials containing nanomaterials during dental and surgical procedures represent possible exposure situations. This is the case, for example, in the treatment of caries in dental care, where fillings containing nanomaterials (e.g., nanoceramic fillings) are usually placed and adjusted to the anatomical shape by grinding the surface with high-speed tools. During this procedure, there is a risk that nanoparticles will disperse into the air and be inhaled by the patient and medical personnel.”²Nanomaterials in healthcare: occupational hazards and their prevention, EU OSHA, E-facts 73, 2013.

These situations of exposure to nanomaterials exist throughout the life cycle of the material. The prosthetist, during the elaboration of the material, can be exposed to it by inhalation. In the case of polishing or removal of a material, it is the patient and the practitioner who may be exposed, by inhalation – and to a lesser extent by swallowing for the patient³Cf. presentation by Prof. Elisabeth Dursun,“Nanoparticles and dental biomaterials” at the 21st Public Health Day, organized by ASPBD on November 4, 2021, 0:45′..

However, it is still too rare to see real benefit/risk approaches and prevention seems to be very weak to date.

What precautionary measures?

Some precautionary operating measures can be adopted during milling, polishing, etc. operations to limit, in fine, the exposure to nanomaterials. Élisabeth Dursun cites some of them in her intervention of November 2021Cf.⁴intervention of Prof. Élisabeth Dursun, “Nanoparticles and dental biomaterials” organized by the ASPBD on November 4, 2021 during the 21st day of public health, based on recommendations of the French-speaking Society of Dental Biomaterials (SFBD) :

• Carve out the restoration in detail before setting, to reduce the amount of material milled for finishing and polishing
• use water to cool and vacuum more efficiently during polishing
• ventilate the premises frequently
• protect staff:
  • Wear a FFP3 mask when polishing, as well as glasses
  • ask the assistants to move away during the polishing
• prefer powder/liquid capsule systems
• use the dam for finishing when the occlusion is not involved
• pay particular attention to vulnerable patients (asthma, chronic bronchial obstruction, etc.)