Fissure Sealant Flashcards
What are the two main types of pits and fissures?
- Shallow, wide, V-shaped fissure – not as concerning
- Deep, narrow I-shaped (bottle neck) fissure – concerning as can act as a niche for biofilm accumulation, biofilm stagnation.
What is a fissure sealant?
It is a low viscosity material which is flowed into a pre-treated pit or fissure which fills the pits/fissures & physically alters the morphology.
Why are pit and fissures prone to dental caries? Why is pit and fissure caries still a problem that needs preventive management?
- fluoride has less effect on pit and fissure caries compared with smooth surface caries
- morphology of pits and fissures, with additional pits, supplemental fissures
- deep. narrow and bottle-neck type fissures are particular prone to caries as they favour plaque retention and plaque disruption is more difficult
- diagnosis of early caries in pits and fissures is difficult - may not diagnose caries until more extensive
a) Early pit and fissure caries can be difficult to diagnose. Why is this?
b) What role do pit and fissure sealants have in the management of early pit & fissure caries or when there is questionable caries?
- a description of pit and fissure morphology and why that makes it difficult to diagnose early caries
- Bitewing radiographs will not show early fissure caries (as 2D image and superimposition of B/L/occlusal tooth structure so caries will only be evident once in dentine
- Fissure sealants can be used to prevent caries but also seal over early carious lesions and if well placed/bonded create a barrier between pits/fissures and the oral environment - remove food source for bacteria in biofilm so arrest caries or at least prevent progression
- placing fissure sealant where caries is questionable can arrest the caries and prevent the need for invasive treatment / removal of tooth structure
a) What is a fissure sealant?
b) How does a fissure sealant prevent caries?
- description of a F/S including key words - low viscosity, physically alters morphology, creates mechanical barrier
- description of: barrier between tooth and oral environment, eliminates environment conducive to cariogenic bacteria
What criteria need to be assessed prior to deciding if a resin-based fissure sealant should be placed?
- need for determining a patient and the tooth are at risk of caries (include patient and tooth-related factors) as this is critical - eg a low risk patient with shallow, wide pits and fissures has no need for a fissure sealant which needs a broader risk assessment of the patient (you should provide examples) and of the tooth (provide examples)
- can a fissure sealant be placed well eg if moisture control cannot be achieved because of tooth position/partially erupted or other patient or operator related factors, then this is a contraindication to placing a resin based sealant
- tooth assessment - if there evidence of caries well into dentine or cavitation of a lesion, then this is a contraindication to applying a fissure sealant alone (may be placed in conjunction with a restoration)
What is the most common type/class of fissure sealant used in the Adelaide Dental School?
light cured resin-based sealant
What do we mean by the term “light cured”? What are the advantages of light cured sealants?
white light with a blue filter initiates the setting reaction / polymerization of the sealant
advantages: control setting, no mixing (less air bubbles), can remove some sealant before curing
disadvantages: polymerization shrinkage, need for light curing unit (but these are really standard in practice so not a real disadvantage)
Why is moisture control so important when placing a resin based sealant?
- micromechanical retention and why this is important
- how poor moisture control impacts on the micromechanical retention eg if saliva contacts etched surface, salivary glycoproteins quickly adsorb, block porosities, prevent rein from flowing into to porosities, therefore prevents micromechanical retention, possible failure of the bond and leakage - risk of caries under the sealant
- salivary contamination is most common cause of sealant failure
What is acid-etching? What type of acid is used and why?
application of acid to the enamel surface removes remaining plaque and pellicle, causes demineralization of surface enamel and creates microporosities (eg demineralizes the prism core) with the enamel
this creates increased surface area for bonding and creates porosities at different angles
Acid etching prepares the enamel for micromechanical retention of a resin based sealant as low viscosity resin flows into the micro porosities
37% phosphoric acid is used: this is the ideal concentration to maximize micro porosity creation for micromechanical retention
Lower concentration acid results in insoluble precipitates - which interfere with bonding
Higher concentration - less penetration of the acid into the enamel and shllower tags form
After etching the tooth is rinsed. Why is this step important?
- removing etch so stopping etching process
- removing etch and any products of demin - leave open pores for flow of resin
After rinsing of the etch, the tooth is dried in preparation for placement of the low viscosity resin sealant. Why is this drying step important?
How should the enamel look after drying?
- thorough drying is essential to enable good bonding/micromechanical retention of the selant
- remaining water will block the porosities created in the etching process
- resins are hydrophobic so the resin will not penetrate the microporosities when water is present
- this prevents formation of resin tags and therefore microleakage or sealant failure is likely
If the tooth is dried well and has been properly etched it should appear frosty white
What are the common reasons for failure of a fissure sealant?
Poor diagnosis/tooth selection
Saliva contamination of etched enamel (inadequate moisture control)
Insufficient etching
Insufficient drying
Too little fissure seal coating
Contamination of airline of triple syringe or oil
Air bubbles and being left in occlusion
Prior to placing acid etch when preparing a tooth for a fissure sealant, the tooth is cleaned with a prophy brush, washed and dried.
Why is washing and drying the tooth prior to placing the acid etch important?
- why a clean surface is important (wash and dry removes debris that has been disturbed through using prohy brush)
- why a dry tooth is important eg water will dilute the acid …..what effect will that have on the etching process?
Why does a fissure sealant material need to have low viscosity?
low viscosity is important for creating resin tags / micromechanical retention
if the resin is not low viscosity it will not flow into the microporosities created in the etching process
some resin materials are thixotropic, meaning they become less viscous under pressure - hence why some resins need to be applied with a special applicator brush that puts the material under pressure (eg runs through a spiral under pressure) so it is less viscous when it is dispensed onto the tooth
