Fissure Sealants and PRRs Flashcards by S P

What are pits?

small pinpoint depressions located at junctions or terminals of developmental grooves

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What is a fissure?

deep, narrow channel or crevice which is sometimes deep

they are formed at the depths of developmental grooves during tooth development

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What is signficant about the anatomy of pits and fissures in preventative dent?*

there is an inaccessible area (0.1mm) beyond the accesible area (0.4mm) that is not visible to the naked eye

toothbrush and probe cannot reach inaccessible area

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What is harboured in inaccessible areas of pits and fissures

harbours microorganisms
+
acts as trap for sugars/food particles

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Why do deep fissures occur so commonly?

during tooth development, enamel calcification begins at tips of cusps and proceeds downwards, when the cusps grow they fuse at completion of the crown
-> often the fusion of 2 cusps is incomplete (causing deep fissures)

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What is the type of enamel that forms at the fissures?

amorphous enamel

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What is the classification of fissures? (4) Name from most to least common*

V-type (34%)
IK-Type (26%)
U-Type (14%)
I-Type (1%)

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Why are fissures susceptible to caries?

they provide ideal environment for the development and progression of active caries

→ complex anatomy of fissure makes it difficult to clean, plaque retentive, periodic refined carbs for nutrition

the highest risk fissure is type IK where there is a bulbous widening and therefore very short route to the dentine for caries to progress

speed of penetration of fissure caries is very fast with devasting results

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How much of a the total tooth surface does occlusal surface account for? How does this compare to the prevalence of pit and fissure caries?

only 12.5% of total tooth surfaces

BUT

accounts for nearly 80% of all caries lesions (8x more likely than smooth surface caries)

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Where are you most likely to find caries in younger children with permanent teeth?

pits and fissures

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Where can you find pits and fissures other than occlusal surfaces of molars/pms?

buccal surface of lower molars
palatal surface of upper molars
palatal pits of anteriors

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What diagnostic method is essential for early detection of pit/fissure caries?

BWs

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Define fissure sealant (4)

What is key to the success of F/S? (1)

a seal in the pits and fissures of susceptible teeth, creating a physical barrier agaisnt biofilm nutrition and prevent acid-forming bacterial proliferation

adhesion to tooth

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Outline the effectiveness of F/S

caries rate w F/S = 30% whereas without is 80%

protective effect is especially important in high risk population

can arrest progression of early non-cavitated lesions (study showed caries lesions that are effectively sealed dont progress)

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Should you do F/S if BW shows caries progressed into dentine?

no, do conservative PRR

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Name the areas of tooth suitable for F/S? (rmb not just pits n fissures) (5)

buccal pits of lower molars
palatal extension of distal occlusal groove of upper molars
palatal pits of upper anteriors
erosion and attrition lesions
chipped or corroded margins of restos

Type of bonding in resin-based vs GIC based sealants?

resin - micromechanical retention (enamel MUST be clean)

GIC - chemical bond

What are the advantages (2) and disadvantages (3) of resin-based F/S?

advantages

durable
flows well into fissures compared to GIC

cons

polymerisation shrinkage = microleakage
stronger biofilm accumulation
(no antibacterial properties )

What are the advantages (3) and disadvantages (1) of GIC F/S?

advantages

chemical bond : ion exchange and true chemical adhesion
anticaries effect attributed to F release and presence of strontium - F initially released rapidly and then slow and continuous over long period of time
F content can be recharged (by applying topical F)

disadvantages

weaker than resin agaisnt occlusal forces

What are the indications of F/S? (4)

deep pits and fissures on O surfaces
suspected/initial O caries in children and young adults
children susceptible to O caries
children coming from non-F areas with increased caries experience

What are the contraindications for F/S? (4)

shallow pits and fissures
well-established caries → cavitated (esp if in dentine)
teeth with proximal caries
partially erupted or not completely erupted teeth → difficult from point of isolation

When can you put F/S on a partially erupted/not fully erupted tooth?

GIC sealants

NOT resin based

2 main aims of RESIN F/S procedure. What might you need to consider.

aim - flow the resin into depths of fissures

adhesion is key (enamel must be clean for micromechanical attachment of resin)

but will etch work on aprismatic enamel?

What are the steps taken before putting resin F/S on?

clean enamel

etch

bond

What is cleaned off the surface of tooth in preparation for F/S? (3)

plaque pellicle debris

What can be used to ensure clean tooth surface before resin F/S? (4)

* brush and pumice with water * minimal fissurotomy * air abrasion (cleans fissures with minimal tooth structure removal) AND rubber dam or equivalent moisture control

Outline the steps for resin F/S procedure. (8)

1. clean tooth (brush n pumice, minimal fissurotomy or air abrasion) 2. acid etch 3. wash and dry 4. keep immaculate moisture control 5. bond and LC 6. flow on sealant and LC 7. check for overhang & ditches 8. check occlusion

Outline the steps for GIC F/S procedure. (6)

1. clean tooth 2. cavity condition (10-20% polyacrylic acid for 10 seconds- doesnt etch but increases SA of tooth to improve wettability) 3. wash thoroughly with water and dry 4. isolate (cotton rolls) 5. place GIC into fissure (can push with lubricated gloved thumb - vaseline or cocoa butter( 6. Protect thin coat of unfilled resin using fuji coat or cocoa butter (esp for anxious child)

**_What is a challenge with placing resin-based F/S in pits and fissures? \*\*\*_**

enamel surface within fissure walls contains amorphous enamel - the layer of enamel rods lie more parallel to tooth surface rather than perpendicular as in cusps→ complicates bonding as etch may not expose ideal micromechanical retention (need to etch perpendicular to enamel rods)

What are some of the reasons for failure of resin F/S? (4)

* partial lifting of the sealant * no antibacterial properties - caries can occur if seal is leaky * resin will not flow into spaces \<200um

What should be added to tx plan if it involves resin based F/S?

must be carefully monitored for leakage and repaired/replaced

Why are GICs still favoured when they are statistically lost more often than resin-based sealants? (3 arguments)

evidence shows small amt of GIC still remains deep in the fissure even if the FS is lost caries observed less frequently after GIC sealants than resin fluoride saturation of tooth from GIC provides ongoing caries resistance

**_Outline Dr Graham Milicich;s FS protocol (5 steps) and justification made after his 15 year study. \*\*\*_**

1. air abrasion or clear enamel surface with very fine needle tip bur to remove amorphous enamel 2. ensure fissures are clean of organic debris and plaque 3. etch 15-20s w 37% phosphoric acid 4. pure GIC smoothed over with resin coated ball burnisher 5. ensure no ditches/overhangs/cacatches → GIC creates a chemically fused seal and micromechanical bond to enamel, even when GIC is lost the sealed enamel remains

What is a PRR? (3)

1. LIMITED removal of caries - remove active caries but leave affected dentine 2. Restore with CR or GIC 3. F/S over remaining sound pits and fissures

Which cases are good to use PRRs?

in some cases where only one section fo a fissure system has caries (?)

What should you do in this case?

remove active caries from occlusal pit and restore, then put sealant over as well (sandwich technique) acts as extra protection then do F/S in rest of tooth

What is the purpose of a resin coat (e.g. Fuji Coat) over GICs?

protects GIC from water absorption while it matures