SBA bank of questions 3

SBA questions (single best answers)

Purpose of keratinised epithelium

Allows to withstand friction from mastication

4 types of gingival fibres

Circular fibres

Dentogingival fibres

Alveolar crest fibres

Transseptal fibres

Epithelial collar which surrounds the tooth. It extends from region of CEJ to base of gingival sulcus

Junctional epithelium

The junctional epithelium has two basal laminas

1. Internal which faces the tooth

2. External which faces the connective tissue of the gingiva

Gingival sulcus contains what which acts as a protective mechanism via a flushing effect.

Gingival crevicular fluid

Membrane found around the root of the tooth and attaches the root to the alveolar bone

Periodontal ligament

Fibres of the periodontal ligament (2)

Interstitial

Principal

Fibres that are randomly arranged throughout the PDL supporting the blood vessels and nerves

Interstitial

Fibres within the PDL that are dense and arranged in bundles running from cementum to bone i.e. holding the tooth in the socket

Principal

5 principal PDL fibres

1. Dento-alveolar crest

2. Horizontal

3. Oblique

4. Apical

5. Interradicular

Individual sockets are separated by what?

Interdental septum

Coronal rim of alveolar bone that follows the contour of cemento-enamel junction and is scalloped in outline.

Alveolar crest

Three features of healthy gingival tissue

Pink

Firm

Stippled

Gingival sulcus 1-3mm deep

What is a reduced periodontium?

When interdental papilla is lost from gingival health

Demarcation between prisms within the enamel is called what?

Rod sheath

Incremental growth lines seen in enamel and are results of enamel's development. When viewed microscopically in cross-section they appear as concentric rings.

Striae of Retzius

Low-molecular-weight protein found in developing tooth enamel and it belongs to a family of extracellular matrix proteins. Function is to organise enamel rods during tooth development.

Amelogenin

Short linear defects found at the dentinoenamel junction formed by entrapment of odontoblast processes between ameloblasts during amelogenesis.

Enamel spindles

Type of linear hypomineralised enamel defect

Enamel lamellae

Small, branching defects found only at the ADJ protruding into the enamel

Enamel tufts

Critical pH for enamel in saliva

5.5

Critical pH for dentine in saliva

6.7

The bulk of the dentine is said to be

Intertubular

Hypermineralised dentine layer within each tubule

Intratubular dentine

Permeability of coronal dentine is __________ than root dentine

Higher

Pulpal innervation

Branches of trigeminal

Odontoblasts produce dentine in response to damage

Tertiary dentine

Odontoblast survives insult and produces tertiary dentine

Reactive

For cementogenesis to begin something must fragment.

Hertwigs epithelial root sheath

A proliferation of epithelial cells located at the cervical loop of the enamel organ in a developing tooth.

Hertwigs epithelial root sheath

4 signs of irreversible pulpitis

Dull throbbing ache

Lasts hours

Starts on it own

Interferes with sleep

4 signs of reversible pulpitis

Short sharp pain

Lasts seconds

Triggered by stimulus

Does not interfere with sleep

Exposed cervical dentine, recession and tooth surface loss could characterise

Dentine hypersensitivity

This theory states that different types of stimuli act on exposed dentine, causing increased fluid flow through the dentinal tubules. In response to this movement, mechanoreceptors on the pulp nerves trigger the acute, temporary pain of dentine hypersensitivity.

Hydrodynamic theory of pain

Desensitising agent that blocks tubules, promotes remineralisation and is an antibacterial agent

Silver diamine fluoride

Inflammation of the gingiva with no underlying bone loss

Gingivitis

Stage I periodontitis

Interproximal bone loss<15% or <2mm from CEJ

Early

Stage II periodontitis

Interproximal bone loss up to coronal third of root

Moderate

Stage III periodontitis

Interproximal bone loss up to mid third of root

Severe

Stage IV periodontitis

Interproximal bone loss up to apical third of root

Very severe

Grade A periodontitis

Slow rate of progression

<0.5

Grade B periodontitis

Moderate rate of progression

0.5-1

Grade C periodontitis

Rapid rate of progression

>1.0

How to calculate the grade of periodontitis

% bone loss / patient age

Histamine's role in the host response

Vasodilation

Increased vascular permeability

What are prostaglandins produced from and what do they cause?

Produced from arachidonic acid in cell membranes of inflammatory cells.

They cause capillary dilation.

What 3 pathological events are involved in the advanced stage of a periodontal lesion? What host cell mediates this?

JE migrates apically

PDL fibres break down

Alveolar bone lost

Plasma cells

Currently periodontally stable

BoP < 10%

PPD <= 4mm

No BoP at 4mm sites

Currently in remission

BoP >= 10%

PPD <= 4mm

No BoP at 4mm sites

Currently periodontally unstable

PPD >= 5mm or

PPD >= 4mm and BoP

Normal bone levels

2mm apical to the CEJ

Gracey curette 1/2

Anterior subgingival

Gracey curette 7/8

Buccal & Lingual posterior teeth subgingival

Gracey curette 11/12

Mesial posterior teeth subgingival

Gracey curette 13/14

Distal posterior teeth subgingival

Columbia Curette 4R/4L is used for?

All surfaces of posterior teeth(UNIVERSAL)

AND Subgingival calculus (1-2mm)

Columbia curette 2R/2L is used for?

All surfaces of anterior teeth (UNIVERSAL)

AND Subgingival calculus (1-2mm)

For calculus removal the ideal angle should be between

60 and 80 degrees

When scaling below the gingival margin, angulation during insertion should be between

0 and 40 degrees

Instrument grasp

Modified pen grasp

Mild alveolar bone loss

<15%

Moderate alveolar bone loss

Coronal third of root

Severe alveolar bone loss

Mid third of root

Very severe alveolar bone loss

Apical third of root

Incipient caries

Up to half the thickness of the enamel, usually not restored and treated with fluoride

Moderate caries

More than halfway through the enamel up to the ADJ

Advanced caries

Caries enters the dentine

Severe caries

Caries more than halfway through the dentine

An apparent radiolucency found just below the CEJ on the root-artefactual phenomenon that imitates caries

Cervical burnout

Zone at the distal cervical margin directly beneath the restoration that appears radiolucent - when the restoration is blacked out the area then appears less radiolucent-there is no secondary caries, just appears that way

Mach band effect

Mobility grade 1

less than 1mm movement

Mobility grade 0

no noticeable movement

Mobility grade 2

1-2mm movement

Mobility grade 3

>2mm movement and/or vertical movement

Furcation grades

I = <3mm horizontal probing

II = >3mm but not all the way through

III = you can pass the probe all the way through

4 aims of NSPT

1. Disrupting and removing the plaque biofilm

2. Removing calculus deposits which impede oral hygiene

3. Decontaminating the root by removing noxious bacterial products i.e. endotoxins

4. Removing the bulk of subgingival calculus from the root surface.

Change in what patient is doing - Important they understand the disease and the role they play in controlling disease.

Behavioural modification

Superficial reddening

Erythema

Swelling

Oedema

Which patients should be screened?

All new patients that attend for an examination

Children and adolescents (ages 7-17)

Patient with codes 0,1,2 at previous examination

What instrument is used to conduct a BPE and why?

BPE probe - ball pointed - no damage to soft tissues

How many grams of pressure should be applied during a BPE?

20 grams

Why do we not screen 3rd molars?

Can give false reading as often partially erupted therefore can give an inaccurate BPE.

When do we screen 3rd molars?

If 1st and 2nd molars are missing.

40 year old female. new patient, MH clear, brushes twice daily and flosses in the evenings. BPE codes of 0,1s,2s. How would she be manage.

Plaque and bleeding indices

Appropriate OHI

Supragingival PMPR

Motion of BPE probe in a bleeding index

Sweeping motion

46 year old male, previous BPE codes of all 2s. Patient is smoker. BPE codes now recorded as all 3s. How would this patient be managed?

6PPC

Periapical radiographs

OHI including smoking cessation

Supra + subgingival PMPR

32 year old female, MH clear, BPE codes all 4s with *UL sextant. How will this patient be managed?

FPA

Radiographs

Plaque and bleeding indices

OHI

Supra + subgingival PMPR

Reviewed 3 monthly - FPA

Does pt need to be referred?

When screening a 10 year old for periodontal conditions which codes are used?

BPE 0-2

When screening children and adolescents, which teeth are examined?

Index teeth UR6, UR1, UL6, LL6, LL1, LR6

BPE around implants

Record pocket probing depths at six sites and any bleeding on probing around the implant

Enamel composition

96% inorganic (mineral) hydroxyapatite

4% organic protein, fat and water

Biological apatite crystals are associated into ________ and are roughly ___________ in cross-section

Rods

Hexagonal

Why is enamel so resilient?

Has a complex microstructure which is hierarchically assembled from structural components exhibiting a nanostructure.

What crystals are closely packed in prism bodies?

Apatite crystals

Enamel is a porous structure. What does this mean? Where are the larger pores found?

Protein left behind allows molecules to sneak through. Larger pores are found at prism junctions.

Arise from changes in prism orientation

Reflect the alternating direction taken by groups of enamel rods as they move away from dentino-enamel junction during formation

Enamel Hunter-Schreger bands

Are prisms curved or straight in inner enamel?

Curved

Are prisms curved or straight in outer enamel?

Straight

Darker lines in the striae of Retzius result from what?

Systemic disturbances in the human body e.g a fever