Adverse reactions and allergy to dental biomaterials Flashcards
What the clinician expects of their dental materials (5)
Ease-of-use.
Appropriate physical/mechanical properties.
Cost-effective biomaterials & devices
Efficacy.
Safety - for the patient & the dental team.
What do we mean by ‘safe’ materials (2)
“Biocompatible materials do not irritate the surrounding structures, do not provoke an inflammatory response, do not incite allergic reactions, and do not cause cancer”
Types of toxic and adverse reaction (3)
Toxicity.
-cytotoxicty / genotoxicity / mutagenicity/carcinogenicity / teratogenicity / neurotoxicity / metabolic toxicity.
Allergic reactions.
-immediate (type I hypersensitivity).
-delayed (type IV hypersensitivity).
Irritant (non-allergic) reactions or intolerance?
How many common allergens present in dental materials? (1)
At least 130
Adverse reaction to biosynthetic hyaluronic acid gel (4)
3% of patients experience allergic reactions to implanted bovine collagen.
HYA is believed to be non-immunogenic.
Case study patient developed allergic-type reaction after third treatment.
Not known if this is reaction to a modified HYA or a contaminant
Synthetic biomaterials: failure via chronic inflammation (3)
Many medical devices have a finite life due to aseptic inflammation
Early artificial TMJ was disastrous (Vitek®) - similar mechanism.
Foreign body response to physical presence of particulate debris (irritant).
“Phantom” risks and the myth of amalgam disease (5)
Dental amalgam contains mercury (Hg), a toxic metal.
Accumulation of higher concentrations of Hg in the body associated with specific clinical symptoms.
Human exposure to Hg is inevitable (air, water, food, and amalgam restorations).
Some believe that Hg in dental restorations has caused an amalgam illness or disease.
Will be covered in future lecture in series.
How common are real adverse reactions to biomaterials? (3)
Generally, allergy rates (e.g. hay fever) are increasing.
Innovation means that dental materials are increasing in range and complexity.
Exposure increases risk
Adverse Reaction Reporting Project results (3)
The clinician (and his/her team) has a far greater risk of developing an adverse reaction than a patient.
Exposure increases the risk associated with any one material.
Adverse reactions to dental materials are generally uncommon and not of a serious (i.e. life-threatening) nature
Why are dental materials so safe given their hazardous contents? (4)
- European regulations: Pre-market testing & the CE mark
- Responsible manufacturing by industry, e.g. improved packaging
- Non-contact operative techniques
- Post-market surveillance
Via Competent Authority (MHRA) due to European regulations.
Via research projects (e.g. Adverse Reaction Units of Bergen University and Sheffield)
Pre-Market testing (7)
Required by law for new biomaterials
Tests based on ISO 10993 guidelines
Exact tests determined by evaluation of risks associated with the material and its clinical application.
Tests include cytotoxicity, haemolysis, irritation, systemic toxicity, & genotoxicity
Manufacturers work with a Notified Body to satisfy a Competent Authority that a medical device (e.g. dental biomaterial) is safe and fit for purpose.
New devices are then awarded a CE mark for sale in Europe / EFTA
All developed nations operate a similar regulatory system (e.g. US FDA)
CE Mark (3)
The award of a CE mark enables goods to be sold throughout the EEA.
It is the result of a risk management exercise including scientific, pre-clinical and sometimes clinical testing.
However, “no amount of experimental study can guarantee the absolute safety of any substance”
Why monitor? The role of post-market surveillance (3)
It provides an “early warnings” of previously unsuspected adverse reactions.
It can be used to identify factors associated with particular adverse reactions.
It permits continued safety monitoring throughout the duration of a product’s use on the market
