Dental Caries Important Notes
1. Types of caries
- Pit and Fissure caries
- It occurs in pits and fissures
- It is represented as a cone with a base towards DEJ and an apex towards the enamel surface
- Smooth surface caries
- It occurs in the unclean proximal surfaces
- The base of the cone is towards the enamel surface and the apex is towards the DEJ
- Residual caries
- It is caries that remains in a completed cavity preparation by the operator intentionally or unintentionally
- Forward caries
- When the caries cone in enamel is larger than that of dentin
- Backward caries
- When the spread of caries along the DEJ exceeds caries in contagious enamel and caries extends into the enamel from DEJ
- Root/senile caries
- Occurs on the tooth that has been exposed to the oral environment
- Recurrent/secondary caries
- It occurs at the borders or underneath the restorations
- Acute/rampant caries
- The lesion is light-colored and infectious
- Chronic/slow-caries
- The lesion is discolored and fairly hard
2. Composition of GIC
Powder:
- Silica 3540%
- Alumina 2030%
- Aluminum fluoride 1.52.5%
- Calcium and sodium fluorides 2025%
- Lanthanum, strontium, and barium in traces
Liquid:
- Polyacrylic acid 45%
- Water50%
- Itaconic acid, maleic acid, tricarballyic acid 5%
- Tartaric acid traces
3. Accelerators and retarders of ZOE cement
Accelerators
- Zinc acetate
- Alcohol
- Water
- Glacial acetic add
Retarders
- Cooling of glass slab
- Glycerine
- Olive oil
- Increasing liquid powder ratio
4. Hybrid or resin-modified GIC
- BISGMA and TEGDMA are added to GIC powder and HEMA to liquid
- They are usually light-cured, less technique-sensitive, and may be finished at the time of placement
- The properties are superior to GIC
- They are recommended for class V restorations and class I and II in primary teeth
5. Compomer
- It is a combination of composite and GIC
- Glass particles are partially silanated and are added as fillers in the composite resin
- There is no water in the reaction
- The properties are inferior to composites but superior to GIC and resin-modified GIC
6. Cermet
- Glass and metal powders were sintered at high temperatures and made to react with liquid
- It improves fracture toughness and wear resistance and maintains aesthetics
7. Sandwich or bilayered restorations
- It uses GIC as a liner under composite restoration
- It increases the retention form as GIC bonds to the tooth and the composite
- Fluoride content reduces secondary caries.
Dental Caries Long Essay
Question 1. Enumerate various tooth-colored restorative materials. Give manipulation, indication, and advantage of silicate.
Answer:
Various tooth-colored restorative materials:
Restorative Materials:
- Glass ionomers
- Composites
- Fused porcelain
- Acrylic resins
- Silicate cement
Manipulation:
- Powder/liquid ratio 1.6g/4ml
- Dispensed on a thick, cool, dry glass slab
- Divide it in 2/3 increments
- Mix with agate spatula in a folded manner to obtain a homogenous mass
- Mixing time 1 minute
Indications:
- For anterior restoration
Advantages:
- An anti-cariogenic property
- Tooth color matching ability
- Ease of manipulation
Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers
- The coefficient of thermal expansion is approximately similar to enamel
- Good insulator
- Its compressive strength is higher than other cement
Dental Caries Short Answers
Question 1. Buccal Object Rule/Slob/Clark’s rule.
Answer:
Buccal Object Rule:
- A standard radiograph is taken
- Shift the cone medially/distally
- Take a second radiograph
- If the object is seen on the same side, the object is placed over the lingual side
- For object localization
Question 2. Caries detecting dyes.
Answer:
1. Dyes for enamel caries:
- Procion Staining is irreversible
- Reacts with nitrogen and hydroxyl groups
- Calcein Bounds with calcium
- Zyglo ZL22 Visible by UV illumination
2. Dyes for dentin caries:
- Infected and affected dentin layers are present
- Basic Fuschia in propylene glycol stains only the infected dentin
Dental Caries Viva Voce
- Double inverted cone type of penetration of dental caries is seen in smooth surface caries
- Pit and fissure lesions are represented by the base of the cone facing each other
- The cervical to-contact area is the common site for proximal caries
- Smooth surface caries is mainly caused by streptococcus mutans
- Patients with salivary levels of streptococcus mutans above 106 CFU/ml are considered at high risk for dental caries
- Remineralization of carious lesions occurs at a pH above 5.5
- Streptococcus mutants and lactobacillus are most strongly associated with the onset of caries and active progression of cavitated lesions
- Root caries is initiated by A.viscosus
- The surface zone of enamel caries is unaffected by caries attack
- The Dentinoenamel junction is the least resistant to caries
- Increased powder in zinc phosphate cement decreases the setting time and solubility and increases strength and film thickness
- Zinc polycarboxylate is the first cement to show adhesion with tooth structure
- pH of zinc polycarboxylate liquid is 1.7
- Mechanical properties of ZOE cement can be improved by adding alumina to the powder and orthodoxy benzoic acid to the liquid
- GIC lacks toughness, and wear resistance and cannot withstand high stress
- ZOE and silicate cement have high solubility and disintegration rate
- GIC and silicophosphate have low solubility
- Resin cement is the least soluble in the oral cavity
- The working time of zinc polycarboxylate is 25 min
- The working time of zinc phosphate is 5 min.