Evidence Based Dental Materials Selection Flashcards
What evidence may be looked at regarding materials?
Clinical longevity/durability Aesthetics Cost effectiveness Pt acceptability Ease of use Safety
What evidence to consider?
Peer reviewed papers:
- RCT
- Systematic reviews (Cochrane)
- Scientific papers
International/national databases
Clinical/senior peers judgement/opinion
Manufacturers marketing materials
Pros of peer reviewed publications?
Peer reviewed
Methods of data must be accurate
Generally accessible to healthcare professionals
Generally include sufficient details as to be understandable/useful
Cons of peer reviewed publications?
Quality of peer review may differ between journals
Other sections may contain more opinion than fact - risk of fraud
Public/GDPs may find key papers behind a paywall
May contain extensive technical jargon
How is a peer reviewed paper produced?
Authors design and do a study
Submit findings to journal = reviewers make comment and recommendations
Manuscript published as a paper
Layout of a scientific paper?
Most highly regarded scientific publications deal with experimental materials/systems and scientific papers based on commercial material data help in lower regard
1st page = title, authors, affiliations, abstract
Intro = describes background, context and rationale for research, conclude with aim/hypothesis
Methods/experiment = describe experimental design and steps, statistics
Results - date generated by the experiments
Discussion = authors considered interpretation of the data
Conclusions = summary of findings, acknowledgements
Aims of peer-reviewed papers?
Raise quality of published research and reduce risk of fraud
Publications form an ever expanding and permanent record of non-clinical and clinical knowledge
How to classify biomaterials?
By material
By application
By tissue interaction
By risk
How to classify by material?
Metals (permucosal implants, amalgam) Polymers (denture base) Ceramics and glasses (ceramic crowns) Composites (resin composite, GI cements) Natural or biological materials
How to classify by application?
CV system
Nervous system
Skin and integument
Skeletal systems - bone, teeth
How to classify by tissue reaction?
Bioinert
Bioactive
Bioresorbable
How to classify by risk?
Important in context of medical devices regulations and safety testing, classified as class I (low),II (intermediate) and III (high) risk based on: Type of exposure - Surface/skin contact - Indwelling - Blood contacting Length of exposure - <24hrs - Days - Permanent
What risk are most dental materials?
Class IIb (intermediate) risk devices
Define biocompatibility
The ability of a material to perform in a specific application with an appropriate host response
Non-toxicity is only part of biocompatibility
Biocompatibility is a site and application specific term
How to test biocompatibility?
In vitro evaluation - Cell free models - Cell culture In vivo evaluation (animal testing) Clinical testing and trail Post market surveillance
Biocompatibility testing = CE mark
Advantages of in vitro determination of biocompatibility?
Rapid
Cost effective
Reproducible
Ethically straightforward/non-controversial
Disadvantages of in vitro determination of biocompatibility?
Poor model of complex situation
Advantages of in vivo determination of biocompatibility?
Whole complex animal model
Disadvantages of in vivo determination of biocompatibility?
Expensive
Intermediate reproducibility
Ethical debate/controversy
Not always a reliable model of human body, tissue or disease
Advantages and disadvantages of clinical trial to determine biocompatibility?
Advantage
- Real human use/clinical model
Disadvantages
- Expensive
- Some ethical issues
- Not always a good representation of real clinical practice (often performed by skilled clinicians, pt’s selected)
Features of post-market surveillance (PMS)?
May provide early warning of hazard or side effect of tx
Some adverse reactions are extremely rare - may only be detected by PMS
Strengthens evidence base for the use of a biomaterial as part of tx
Implementation may be expensive
PMS is required by law
Why are dental materials safe?
Gone through packaging, pre-market testing, post-market surveillance, regulatory environment including CE marketing, clinical vigilance
Pre-market testing features?
Required by law for new biomaterials
Tests based on ISO 10993 guidelines
Part 1 = guidelines on test selection, determined by evaluation of materials risks and clinical application
Tests include cytotoxicity, haemolysis, irrigation, systemic toxicity, genotoxicity
Additional studies not legally required but data may be submitted towards CE marking or FDA approval
Testing and reporting associated with determination of biocompatibility?
In vitro evaluation
- Cell free models (stimulated body fluid)
- Cell culture
In vivo evaluation (animal testing)
Clinical testing and trial (pre-market)
Post market surveillance (e.g. adverse reaction reporting project)
What is Branemark associated with?
Pioneering osseointegrating implant (TiO2 implants), careful surgery and pt selection
What did in vitro biocompatibility of titanium discover?
TiO2 surface biocompatible
Readily colonised by cultured osteoblasts
Rough modified surfaces were superior in terms of cell response (e.g. collagen type 1 production)
What have in vivo studies found regarding TiO2 implants?
Osseointegrating an established term in 1980s
Titanium implants still studied in animal models today
HaP was superior to a titanium alloy in terms of osseointegration
Summary of in vitro and in vivo studies?
Titanium (TiO2 surface) exhibits excellent in vitro and in vivo compatibility
Published scientific reports must be read and interpreted very carefully, especially where it is suggested you change your clinical practice
In vitro and in vivo date alone is rarely/never sufficient to change clinical practice
What did Pierre Simonis1,Thomas Dufour2and Henri Tenenbaum1. Clinical Oral Implants Research, 2010 find regarding implant survival?
Long term implant cumulative survival rate up to 16 yrs was 82.94%
Prevalence of biological complications 16.94%
Cumulative complication rate after an observation period of 10-16 yrs was 48.03%
Majority of implant losses and biological complications were concentrated in a small no of pts
= Long term survival rate but biological and technical complications were frequent
= Pts with a history of periodontitis may have lower implant survival rates than pts without a history of periodontitis (and prone to peri-implant mucositis and peri-implantitis)
Key points in material testing?
No amount of testing guarantees absolute safety
No material is risk free
Intention of testing, clinical evaluation and monitoring = reduce risks as far as possible to acceptable levels
Clinical vigilance remains a critical element in ensuring pt safety
Published biocompatibility studies are of no real value in clinical decision making
Clinical trials have value but must be read carefully
