Nanos and dental care

Nanos and dental care

By the AVICENN team – Last updated July 2022

Nanomaterials found in dental products

In the field of dentistry as in others, it is difficult today to distinguish 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 lists three “entities” (companies) that reported nano for “the manufacture of instruments and supplies for medical and dental use”.
This report identifies 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, nanoparticles could be found in dental practices¹Who’s afraid 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 suction.
  
  

What are the known risks?

Routes of exposure and risks

Few “public” resources on the specific risks of nanoparticles in dental products are available online.

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

However, the European Agency for Safety and Health at Work points out that “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 tooth decay 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 can be exposed to it by inhalation during the elaboration of the material. The patient and the practitioner can be exposed, during polishing or material removal, 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′..

Unfortunately, actual benefit/risk assessments are few and far between and prevention currently limited.

Possible precautionary measures

Some precautionary operating measures can be adopted during milling, polishing, etc. to limit, in fine, the exposure to nanomaterials. Élisabeth Dursun mentions some of them during a conference in November 2021⁴Cf. intervention 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 it sets, to reduce the amount of material milled for finishing and polishing
• use water to cool and more efficient suction during polishing
• ventilate the premises frequently
• protect staff:
  • wear FFP3 masks and glasses when polishing
  • keep the assistants at a safe distance during polishing
• prefer powder/liquid capsule systems
• use a rubber dam for finishing when occlusion is not a concern
• pay particular attention to vulnerable patients (asthma, chronic bronchial obstruction, etc.)