RCC 1001 Final

In the closed sandwich technique, at what thickness is the liner applied?

0.5 mm
- In the open sandwich, applies as >1.0 mm base

In the open sandwich technique, the GI/RMGI must form the contact with the adjacent teeth. (T/F)

False
- Must NOT form the contact (must be below)

Conventional GI provides a significant increase in dentine hardness at the cervical margins, while RMGI does not. (T/F)

True, creates highest amount of calcium -> decreases caries risk

GIC/RMGI are useful in a restoration because they provide:

A better seal at dental margins (stabilize adhesive interface) and release fluoride
- Requires composite lamination to improve resistance to forces

All of the following are advantages of deep marginal elevation, except:
A. Supragingival elevation of margins
B. Seals dentin
C. Creates undercuts to stabilize restoration
D. Geometry for inlay/onlay restorations

C, fills undercuts and reinforces undermined cusps

Overall, DME is a successful long-term solution

Surefill SDR is a bulkfill flowable with less shrinkage, but it should not be placed on what surfaces?

Occlusal and proximal, due to its low filler content

Enamel is avascular, while the dentin-pulp complex is vital and responds to injuries. (T/F)

True

The dentin-pulp complex has a cellular-driven defense against:

pH fluctuations in the biofilm
- Tubular/peritubular mineralization, tertiary dentin

Deep dentin has less tubules with smaller diameters. (T/F)

False, more tubules (38,000-45,000) with larger diameter (1.6-2.5 micrometers)

Adhesive binds better at the superficial dentin. Why?

Less water content, and the adhesive is hydrophobic
- Deep dentin has more peritubular dentin (greater SA), however its high water content makes adhesion more difficult

When does the DPC react to caries?

Early, before demineralization reaches DEJ or enamel breakdown
- Pre-dentin reduction, pulp cells in cell-free-zone, and dentin hypermineralization (tubular sclerosis)

Tubular sclerosis forms a ___________ zone.

Translucent (minerals in tubules gives homogenous appearance)

In the progressive stages of lesion formation, what is the first zone to form?

Translucent (sclerotic) zone, followed by zone of demineralization
- Reactive dentin is next, and the zone of bacterial invasion forms last

Tertiary dentin is not as hard as primary dentin. (T/F)

True, less mineralized and irregular tubules

Histology of primary dentin

- Smooth odontoblastic processes
- No intratubular crystals
- Intertubular dentin cross-banded collagen and dense-apatite crystals

Hard, only cut by bur or sharp cutting intstrument

Secondary dentin has the same histology and clinical appearance

How does sclerotic dentin differ from primary dentin?

Dark and harder
- Can be seen before demineralization reaches dentin

Sclerotic vs tertiary dentin

Sclerotic
- Translucent zone
- Responds to aging, mild irritation
- Seal dentinal tubules to wall of lesion
- Crystalline material precipitates
- Harder than normal dentin

Tertiary
- Reaction = reparative
- Responds to caries, attrition, and operative
- Localized dentin deposit
- Not as hard as primary

Affected dentin contains less bacteria than infected dentin. (T/F)

True

Firm dentin is infected dentin. (T/F)

False, it is affected
- Infected dentin is soft dentin

Histologically, firm dentin may be referred to as:

Demineralized intertubular dentin
- Collagen cross-linking remains
- Remineralizable as long as pulp stays vital
- Formation of intratubular fine crystals
- Transparent appearance

All of the following is a characteristic of soft dentin, except:
A. Denatured collagen
B. Bacteria
C. High mineral content
D. No self-repair

C, low mineral content

The transition between soft and firm dentin has a ____________ texture.

Leathery

The difference between the zones becomes less distinct with rapidly progressing lesions. (T/F)

True

Infected dentin is remineralizable. (T/F)

False

What is considered hard dentin?

Tertiary dentin, sclerotic dentin, and normal (or sound) dentin

In slow progressing lesions, what occurs with the tubules?

Sealing of tubules and occlusion
- In rapid lesion odontoblast processes are destroyed with open tubule pathway

Diagnosis of reversible pulpitis includes:

- Presence of pain
- Color
- Periapical lesions

Diagnosis of irreversible pulpitis includes:

- Controlled bleeding
- Infection/trauma?
- Cold test response

If bacterial invasion penetrates the tertiary dentin,

A severely inflamed pulp occurs, followed by necrosis

Cavitated lesions cannot be arrested in their progression. (T/F)

False, cavitated or intact can be arrested by plaque control

When reducing cusps for a complex restoration, how much should functional cusps be reduced?

2-2.5 mm
- Non-functional cusps should be reduced 1.5-2 mm

Functional cusps are 2x more likely to fracture than non-functional cusps. (T/F)

False, less likely
- Buccal cusps fracture more for maxillary arch and lingual cusps fracture more for the mandibular arch

Retention grooves should be placed ______ mm (inside/outside) the DEJ.

0.2 mm, inside the DEJ
- With depth of 0.3-0.5 mm (1/4 round bur or 169L)

What bur is used for a horizontal slot?

Round bur #1, 0.5 mm inside the dentin

What burs are used for placing an amalgam pin and at what depth?

#330 or #245 at a depth of 1-1.5 mm
- The #4 round bur is used to contra-bevel on the junction of the pulpal floor

As a rule, one metal pin per missing line angle should be used. (T/F)

True

The preparation prior to placement of a metal pin should be _______ in depth.

4 mm
- 2 mm for amalgam, 2 mm for metal pin

Metal pins can only be placed vertically. (T/F)

False, vertically and horizontally

What should the position of the metal pinhole be?

No closer than 0.5-1 mm from DEJ or 1-1.5 mm from external tooth surface
- Should be placed parallel to external surface of tooth

Complex amalgam restorations have proven longevity. (T/F)

True

What is the resistance form for complex amalgam?

90 degree CSM, rounded internal angles, and a depth of at least 1.5 mm

What is the retention form for complex amalgam?

Convergent, dove tails, retention features (slots, coves, box, pin)

What are the indications for a complex RBC restoration?

- Provisional restoration for teeth with questionable prognosis
- Interim restorations during disease control process
- Financial cost

How can you prevent errors in axial contour during a RBC complex restoration?

Use the appropriate band and wedge

How does vital pulp therapy preserve pulpal health?

Formation of tertiary reparative dentin or calcific bridge

Electric pulp test stimulates a ______________ sensation. A reading between _________ represents vital pulp.

Tingling, 1-79 (necrotic = 80)

In reversible pulpitis, the response to cold is grossly exaggerated. (T/F)

False, slightly exaggerated (hyperresponsive)
- Requires stimulus for painful response of short duration

How is asymptomatic irreversible pulpitis diagnosed?

Clinic and radiographic observation of caries extending to pulp

Symptomatic irreversible pulpitis' EPT is WNL. (T/F)

True, only hyper-responsive (grossly exaggerated) + prolonged (>10 s) response to cold
- Spontaneous severe pain can occur

________________ is a prerequisite for reparative bridge formation.

Moderate inflammation, for tissue repair following pulp capping

Indirect pulp therapy has a better prognosis than direct. (T/F)

True (90% vs. 80%)
- Best prognosis overall: shallow pulpotomy and root canal (96%)

Components of indirect pulp caps

From most deep to shallow:
1. Demineralized (affected) dentin
2. Bactericidal liner (seals dentin) -> calcium hydroxide and RMGI sealing liner
3. Restorative material (placed 8-12 weeks later)

All of the following are contraindications for indirect pulp capping except:
A. Periradicular lesion
B. Pain lingers following thermal test, after return to mouth temperature
C. Pulpal response to tests is WNL or slightly exaggerated
D. Spontaneous pain
E. Percussion sensitivity

C

A mechanical exposure in what region would not be suitable for direct pulp capping?

Cervical level (class IV)
- Pulp coronal to exposure may have compromised blood supply

A vital pulp is not required for direct pulp capping. (T/F)

False, required and should be asymptomatic + WNL (same requirements as indirect)
- Exposure should also be small w/ minimal pulp trauma

What needs to be controlled prior to direct pulp capping procedure?

Bleeding (hemostasis using 3% sodium hypochlorite solution)
- If bleeding is not easily controlled, perform endo treatment instead

What is the coding for direct pulp capping?

3110 (3120 for indirect)

Factors that have a poor prognosis for pulp capping

- Large, lateral pulp exposure
- Prior symptoms of spontaneous, percussion, + heat
- Older patient
- Contamination
- Poor patient health
- Calcifications (decrease blood supply)
- Hyperocclusion

What is involved in caries diagnosis?

Determine caries activity by detection + patient factor
- Detection: extend of bacterial destruction
- Patient factors: salivary flow, social factors, diet, etc.

What instruments can be used for tactile caries detection?

Probe and blunt explorer
- Use gentle pressure

Caries progression through enamel is slow, and can take _________ (months/years)

6-8 years

Occlusion lesions are difficult to see radiographically. Why?

Superimposition of dense B and L cusps
- Can only see on a radiograph when lesion has passed the DEJ

Proximal lesions are better diagnosed radiographically or visual-tactile?

Radiographically, as difficult to perform visual tactile exploration
- Usually "kissing lesions" at/apical to the contact point

D1 lesions are indications for use of ortho bands. (T/F)

True, if no cavitation is present visually (need to perform tactile exam)

How does the DIAGNOdent work?

Infrared laser light -> fluoresce enamel -> determines extent of demineralization -> numeric score 0-99 (30+ = caries)
- Caries can also be heard (prior to visual detection)
- Tip must be rotated around vertical axis for proper reading

Caries increase tooth fluorescence. (T/F)

False, decrease due to increased scattering

The electrical conductance measurement shows how caries conduct electricity better than sound tooth structure. (T/F)

True, due to much lower electrical impedence

How does an inactive lesion appear with visual tactile examination?

- Enamel yellowish white, dentin brown-black
- Free from plaque, dry
- Smooth, shiny, hard surface

Enamel defects during matrix formation (_________ phase) is called:

Secretion phase, called hypoplasia (external defect on thinnest portion of affected enamel)

How can fluorosis be differentiated from caries?

Fluorosis has a symmetric distribution on homologous teeth (seen on multiple teeth)

What process does fluorosis interfere with?

Enamel mineralization, reducing the deposition of mineral and withdrawal of the organic matrix and water
- Hypomineralization (increased porosity) of subsurface layer

The brown lesions of molar-Incisor hypomineralization (MIH) are caused by:

High protein content
- Subject to enamel breakdown soon after eruption -> caries

What two factors are used to determine the ICDAS score?

Visual appearance and histological depth (after sectioning)

ICDAS scores

0. Sound enamel
1. White/brown, confined to fissure (80% outer enamel, 10% dentin)
2. White/brown, beyond fissure (no loss of surface integrity, 50% inner enamel and 50% into outer 1/3 of dentin)
3. Microcavitation of enamel (lesion depth 77% in dentin)
4. Shadow of dentin (intact walls and ridges) (lesion depth 88% into dentin)
5. Distinct cavitation w/ exposed dentin (less than 1/2 tooth structure, 100% in dentin)
6. Extensive cavitation (100% in dentin, reaching inner 1/3)

In the ICDAS system, obvious decay is seen at:

Codes 4-6

In ICDAS code ____, a caries biopsy should be carried out in medium and high risk patients if the DIAGNOdent reading is _____________.

Code 2, 20-30

Five or more caries lesions in the last 3 years is indicative of a high caries risk. (T/F)

False, 3 or more
- Xerostomia, suboptimal fluoride exposure (+ other factors that increase caries risk) -> high caries risk

What is the most powerful indicator of caries risk?

Past (fillings, etc.) and current (active) caries experiences

What is the resting and stimulated SFR for a high caries risk individual?

- Resting: <0.2 ml/min
- Stimulated: <0.7 ml/min

In a moderate caries risk patient, you would recall the patient every ________ months and perform bitewings every ______ months.

Recall every 3-6 months, perform bitewings ever 12-18 months

If the patient has one tooth missing due to caries, they are placed in the _________ risk category.

High
- Other factors include frequent meal exposures, mother had caries lesion in last 6 months, special health care needs (6-14 years old), radiation therapy, xerostomia

A high caries risk patient presents with caries that have not progressed into the dentin. What is the appropriate treatment?

Seal (E1) or seal + PRR (E2)

The mechanism of action of fluoride is dependent on the ______________ of oral fluids.

Ion availability (in both saliva and biofilm fluid)

Prescription fluoride toothpaste (1.1% NaF) is contraindicated for:

Children under 6, pregnant + nursing mothers, elderly with renal impairment

Fluoride varnish (5% NaCl) is useful for:

Remineralization of non-cavitated lesions

Fluoride and chlorhexidine should be used simultaneously to reduce caries risk. (T/F)

False, cancel each other out
- Wait at least 1 hour after chlorhexidine (chemical antiseptic) use to use fluoride

To be effective, xylitol dosage should be __________ daily.

6-10 grams
- After 2 years, all plaque bacteria removed from all oral surfaces + teeth are hard, shiny, and white

Arginine increases caries development. (T/F)

False, present in saliva (50 uM) -> converted to ammonia (base to counteract acidic foods) via ADS -> caries-free mouth

Abfraction

Cervical loss of tooth structure due to flexural forces (non-carious)
- Fracture of enamel rods on facial

Abrasion lesions present as:

Smooth, U/V-shaped concave lesion on facial root surface

Abrasion alone is not damaging to teeth, it is the combination of it with acids. (T/F)

True
- Toothpaste + acid -> loss of 1 mm of enamel in 2 years

Extrinsic causes of erosion appear on the ___________ surfaces.

Occlusal and labial

Intrinsic causes of erosion appear on the __________ surfaces of maxillary teeth and the ___________ surface on mandibular teeth.

Occlusal and lingual of maxillary and facial of mandibular

Why do NCCL occur in the cervical region?

Prismatic + brittle enamel and stress concentrates there

Theory of thermal shock

Thermal shock transferred from oral cavity through restorative material to the pulp
- Suggests thermal insulating base for amalgam (max 0.75 mm thickness)

Theory of pulpal hydrodynamics

Gap between prep + restorative material -> dentinal fluid flows through -> with cold, fluid contracts + flow increases -> generates action potential in nerves -> perceived by mechanoreceptors as pain

RBC should only be used for a class V restoration if there is perfect isolation and enamel is present. (T/F)

True, and if restoration is not complex
- Otherwise, use amalgam or RMGI

Amalgam preparations for class V restorations involve ___________ for improved retention.

Four-cove retention
- Use 1/4 round bur, depth of 0.25 mm

When should lesions be restored?

Cavitated, active, noncleansable, and not amenable by fluoride

Asymptomatic, non-cavitated D2 and D3 lesions should not be restored. (T/F)

False, can be restored, depending on patient's caries risk and consent