Microplastics in Dentistry—A Review
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action in the contents of landfill which causes its decomposition. The physical parameters like pH, temperature, and oxygen content of the landfill leachate varies over a
period of time which affects its reactivity. Often a heterogenous mixture of commercial, mixed industrial, and municipal waste are dumped into a landfill site giving
rise to leachate comprising of organic and inorganic matter, xenobiotic compounds,
and heavy metal ions. This reactive leachate interacts with RBC which releases
its constituent monomers, oligomers, and BPA. The United States Environmental
Pollution Agency (USEPA) Office through computer simulations proposed that an
accidental release of dental composites while transportation of dental waste or any
malfunction of the landfill liners are the only potential causes of environmental
contamination by dental composites [39].
Another reason for concern is when RBCs are discarded in coastal landfill sites and
areas that may be subjected to coastal erosion. If such sites are subjected to natural
disasters like floods, or lost to sea due to coastal erosion, RBCs can cause environmental pollution. In view of this, if RBCs are subjected to incineration, the risk can be
mitigated. In clinical practice, the finishing and polishing of composite restorations
while placement as well as while removing a damaged composite restoration, there
is release of particulate as well as microparticles consisting of monomers which are
released into the waste water [8].
Onlays, inlays, and crowns are made of highly polymerized RBC through
CADCAM milling. This process releases fine microparticles which are released
into municipal waste water systems. These microparticles which are <5 mm act as
direct pollutants and can also attach to biotoxins or Persistent Organic Pollutants
(POPs) like polychlorinated biphenyl (PCB). These microplastics after adsorbing
POPs can gain access to food chain by bioaccumulation. They are ingested by
plankton, fish, mussels, barnacles, and seabirds. The harmful effects in aquatic life
caused by consumption of microparticles can be due to accumulation of such particles
in the organism and toxicity arising from them, contaminants leaching from them and
ingestion of other attracted pollutants which are bound to these particles. Additives
released from these microplastics like BPA can disrupt the endocrine function of
aquatic organisms affecting their development, reproduction, and motility [39]. BPA
even at small concentrations of ng/L to mg/L is seen to affect the endocrine function
of crustaceans and fishes and also causes molecular as well as whole body effects.
5 Impact on Human
Studies have shown that the release of free monomer continues for months after a
restoration is placed. They are detected in saliva and urine of the individuals. This
free monomer reaches the environment through human excreta. When individuals
with RBCs are cremated or interred, the RBC monomers from the oral cavity reach
the environment through crematoria waste and emissions or by exposure to ground
water. An RBC restoration that has been inside the oral cavity of an individual for
169
action in the contents of landfill which causes its decomposition. The physical parameters like pH, temperature, and oxygen content of the landfill leachate varies over a
period of time which affects its reactivity. Often a heterogenous mixture of commercial, mixed industrial, and municipal waste are dumped into a landfill site giving
rise to leachate comprising of organic and inorganic matter, xenobiotic compounds,
and heavy metal ions. This reactive leachate interacts with RBC which releases
its constituent monomers, oligomers, and BPA. The United States Environmental
Pollution Agency (USEPA) Office through computer simulations proposed that an
accidental release of dental composites while transportation of dental waste or any
malfunction of the landfill liners are the only potential causes of environmental
contamination by dental composites [39].
Another reason for concern is when RBCs are discarded in coastal landfill sites and
areas that may be subjected to coastal erosion. If such sites are subjected to natural
disasters like floods, or lost to sea due to coastal erosion, RBCs can cause environmental pollution. In view of this, if RBCs are subjected to incineration, the risk can be
mitigated. In clinical practice, the finishing and polishing of composite restorations
while placement as well as while removing a damaged composite restoration, there
is release of particulate as well as microparticles consisting of monomers which are
released into the waste water [8].
Onlays, inlays, and crowns are made of highly polymerized RBC through
CADCAM milling. This process releases fine microparticles which are released
into municipal waste water systems. These microparticles which are <5 mm act as
direct pollutants and can also attach to biotoxins or Persistent Organic Pollutants
(POPs) like polychlorinated biphenyl (PCB). These microplastics after adsorbing
POPs can gain access to food chain by bioaccumulation. They are ingested by
plankton, fish, mussels, barnacles, and seabirds. The harmful effects in aquatic life
caused by consumption of microparticles can be due to accumulation of such particles
in the organism and toxicity arising from them, contaminants leaching from them and
ingestion of other attracted pollutants which are bound to these particles. Additives
released from these microplastics like BPA can disrupt the endocrine function of
aquatic organisms affecting their development, reproduction, and motility [39]. BPA
even at small concentrations of ng/L to mg/L is seen to affect the endocrine function
of crustaceans and fishes and also causes molecular as well as whole body effects.
5 Impact on Human
Studies have shown that the release of free monomer continues for months after a
restoration is placed. They are detected in saliva and urine of the individuals. This
free monomer reaches the environment through human excreta. When individuals
with RBCs are cremated or interred, the RBC monomers from the oral cavity reach
the environment through crematoria waste and emissions or by exposure to ground
water. An RBC restoration that has been inside the oral cavity of an individual for