Periodontal Anatomy

Question 1

What are the 3 parts of evidence based dentistry

Answer 1

dentist’s expertise
scientific evidence
Patient needs and preferences

Question 2

What is PICO

Answer 2

Population to be examined
Intervention that is to be inspected
Comparison to what is currently known
Outcome to be evaluated

Question 3

What are the steps for making an evidence based decision in practice

Answer 3

Formulate a PICO question
Research the PICO question and collect evidence
Analyze the data that has been collected
Apply the data to the dental practice
Evlauate the results

Question 4

What is the ranking of scientific evidence

Answer 4

Systematic review/meta analysis
RCT
Controlled trials
Cohort studies
Case-control studies
Cross-sectional studies
Case report studies

Question 5

What is the difference between sensitivity and specificity

Answer 5

Sensitivity is the ability of a test to correctly identify diseased individuals
Specificity is the ability of a test to correctly identify a healthy individual

Question 6

Internal validity vs external validity

Answer 6

Internal validity is the soundness of the study, including bias and statistics
External validity is how much the study relates to the general population

Question 7

Where does the vascular supply of the periodontium originate

Answer 7

The external carotid artery and its main branches, lingual, facial, and maxillary arteries.

Locally the blood supply comes from the supra-periosteal vessels and the vessels from the PDL and bone

Question 8

What is the main innervation for the periodontium

Answer 8

The trigeminal nerve and its branches

Question 9

What is attached gingiva

Answer 9

The gingiva from teh base of the sulcus to the mucogingival junction
Consists of thick lamina propria and deep rete pegs
Goaslind et al reported the gingival thickness is 1.25mm+/- 0.42mm

Question 10

Where does keratinized attached gingiva extend

Answer 10

Gingival margin to the mucogingival junction

Question 11

What is alveolar mucosa

Answer 11

non-keratinized covering of the alveolar bone, from the mucogingival jumction apical

Question 12

What is Ante’s law?

Answer 12

The root surface area of the abutment teeth must be equal or greater than that of teeth being replaced with pontics, which determines the number of teeth required for a bridge.

Question 13

What are the characteristics of healthy gingiva?

Answer 13

Coral pink, firm, follows the CEJ of the teeth, may be stippled or pigmented.

Question 14

What are the 5 types of gingival fibers

Answer 14

Dentogingival group
Alveologingival group
Dentoperiosteal fibers
Circular group
Transseptal group

Question 15

What is the composition of the oral mucosa

Answer 15

masticatory mucosa (gingiva/hard palate)
Lining mucosa (alveolar mucosa, floor of mouth)
Specialized (dorsum of tongue)

Question 16

Oral (masticatory) epithelium characteristics

Answer 16

Orthokeratinized stratified squamous
surface cells lose nuclei and contain keratin
Extends to the sulcular epithelium

Question 17

Oral sulcular epithelium characteristics

Answer 17

Epithelium that lines the sulcus
No rete pets in healthy tissue
nonkeratinized

Question 18

Junctional epithelium characteristics

Answer 18

Attaches to the tooth via hemidesmosomal layer and basal lamina
nonkeratinized
permeable
most apical part lies at the CEJ in healthy tissue

Question 19

What are the 4 layers of the masticatory epithelium

Answer 19

Stratum Basale (cuboidal cells at the basement membrane)
Stratum Spinosum (spines contain Langerhans cells for immune surveillance)
Stratum granulosum (cells appear flat, keratinocytes migrating from stratum spinosum known as granular cells)
Stratum corneum (outermost layer, dead cells that are ortho and Para keratinized)

Question 20

Where is the widest and narrowest zones of gingiva?

Answer 20

Widest in the Maxillary anterior area

Narrowest facial of Mandibular premolars

Question 21

Composition of connective tissue

Answer 21

fibrous, mostly type 1 collagen, ground substances, mucopolysaccharides. Contains WBC, lymph, and nerves
average width greater than 1mm

Question 22

What determines of epithelium is keratinized or nonkeratinized

Answer 22

The underlying connective tissue.

Question 23

What is periosteum and what is its function

Answer 23

Periosteum is highly vascular connective tissue covering all boney surfaces except joints and muscle attachments
Consists of an inner cambium layer (containing osteoblasts and osteoprogenitor cells) and an outer fibrous layer
Involved in bone healing and bone regeneration. Also a channel for blood supply and nutrients for bone tissue

Question 24

Where is the average width of PDL the greatest and where is it the narrowest

Answer 24

Greatest at the apex, and narrowest in the middle

Average widthe of PDL is 0.2mm, wider as you age

Question 25

What provides blood supply to the PDL

Answer 25

Superior and inferior alveolar arteries.

PDL is vascular tissue

Question 26

What are the functions of the PDL

Answer 26

protect vessels and nerves
Transmit occlusal forces
Attach the tooth to bone
Perform formative and remodeling functions

Question 27

What are the fibers of the PDL

Answer 27

alveolar crest, horizontal, oblique, interradicular, and apical
Oblique most numberous

Question 28

Describe and define Ankylosis

Answer 28

fusion of cementum and alveolar bone with obliteration of the PDL
Occurs after chronic periapical inflammation, tooth reimplantation, and occlusal trauma

Question 29

What is the composition of alveolar bone

Answer 29

Cortical bone
Calcellous trabeculae
Alveolar bone proper

Question 30

What are cellular and acellular cementum

Answer 30

acellular cementum is located on the enamel at the CEJ. No cementocytes and forms slowly
Cellular cementum is located at the apical 1/3 of the root, is more irregular and forms rapidly. It’s width increases with age

Question 31

How does cementum join the enamel

Answer 31

60% the cementum and enamel overlap
30% cementum and enamel form a butt joint
10% of the cementum and enamel are separated by a gap

Question 32

What is the difference between intrinsic and extrinsic cementum

Answer 32

intrinsic is cementum fibers produced by cementoblasts

extrinsic is made of sharpeys fibers from the PDL

Question 33

How does the junctional epithelium attach to the cementum

Answer 33

Via hemidesmosomes and replicates every 5 days

Question 34

What is the composition of the TMJ disc

Answer 34

dense connective tissue

Question 35

Describe the movement of the TMJ

Answer 35

Upper compartment has a translational movement

Lower compartment has rotational movement

Question 36

What is meniscal derangement with and without reduction

Answer 36

with reduction - the disc as well as the posterior band of the meniscus is anteriorally placed, but moves into proper position during opening
without reduction - the meniscus remains anteriorly displaced at full opening

Question 37

Describe the 4 types of collagen

Answer 37

Type I - skin, tendon, vascular ligature, organs, bone
Type II - Cartilage
Type III - reticular fibers, found alongside type I and in smooth muscle
Type IV - forms basis of cell basement membrane

Question 38

Supracrestal tissue attachment height

Answer 38

Garguilo
connective tissue 1.07mm
Junctional Epithelium 0.97mm
Sulcus 0.69mm

Question 39

What happens when the supracrestal attachment is violated

Answer 39

periodontal bone loss and inflammation may occur
The body will try to re-create the supra-crestal attachment
Gunay study found more BOP and PD interproximal when the margin was less than 1mm from the bone

Question 40

What is the most common area of recurrent pockets

Answer 40

mesial aspect of maxillary first premolars and first molars

Question 41

What is the relationship between tooth support and root morphology

Answer 41

Root curvatures and concavities increase periodontal support due to multi-directional fiber orientation
multirooted teeth have increased support and resistance to applied forces
divergent roots increase stability and allow for more bone support
Conical roots have less attachment area and are not as stable
Enamel pearls can weaken periodontal attachment
Root fractures can lead to periodontal destruction

Question 42

Which muscles elevate and depress the mandible

Answer 42

elevate - temporalis, medial pterygoid, and masseter

Depress - Lateral pterygoid, digastric, and mylopyoid