2 - Connective Tissue, PDL, and Bone

Question 1

What can you tell me about the buccal plate thickness?

Answer 1

Cook 2011 - Based on CBCT data, the labia plate thickness in this phenotype patients (based on probe visibility) is 1/2 that of the thick/average phenotype

Ghassemian 2012 - Based on CBCT data, overall mean thickness of central incisors is 1.05mm. Greatest thickness is over lateral incisors

Huynh- Ba 2010 - Based on clinical data, 87% of anterior teeth with buccal plate <1mm

Temple 2017 - Based on CBCT data, the thickness in the mandible increases from anterior to posterior. The thinnest sites were MAN 1PM and MAX 1M mesial root

Question 2

What is the relationship between the alveolar crest and CEJ?

Answer 2

Ritchey and Orban

In health, the alveolar interdental crests are parallel to the CEJ.

Flat IP = narrow interdental crest
Convex IP = wide interdental crest

Question 3

Describe cortical and lamellar bone in the MAX/MAN

Answer 3

Lindhe 2013

Mandible with a thick cortical cap (1.8mm) and greater amounts of lamellar bone (60-70%)

Maxilla with a 0.8mm cortical cap and more bone marrow

Question 4

What are some quick facts about collagen

Answer 4

Amino acid sequence = Gly-X-Y. 10% are Gly-Pro-HydroxyPro
Alpha chain assembled into procollagen triple helix on RER. Transported to Golgi where it is processed by cleaving ends to form Tropocollagen and then secreted in vesicle. Arranged in sheets to make fibrils and then fibers
1 - most abundant
4 - Basement membrane
7 - Anchoring fibrils

Question 5

Where are fenestrations and dehiscences most common?

Answer 5

Elliot and Bowers

US skulls

MAX 3X fenestrations (MAX 1M)

MAN 2X dehiscence (PM)

Question 6

What are Epithelial Rests of Malassez?

Answer 6

HERS touches the tooth and induces the dental papilla cells to differentiate into odontoblasts

Mantle dentin is laid down. HERS breaks down and becomes the only epithelial cells present in the PDL as the ERM

Question 7

What is the prevalence of palatal exostoses and tori?

Answer 7

Nery - 40% skulls European
Larato - 30% Mexican skulls
Sonnier - 56% tubercles, 81% bilateral. 11mm from GPF

Sonnier - 20% tori. Females

Question 8

What is the prevalence of mandibular tori?

Answer 8

Sonnier - 27% skulls. 74% bilateral

Question 9

What is the prevalence of buccal exostosis and lipping?

Answer 9

Horning - African American skull study

Exostosis 7% teeth, 77% patients

Lipping 17% of teeth, 73% patients

NO CORRELATION w/ occlusal attrition and widened PDL. Goes against buttressing bone theory

Question 10

Discuss the crestal lamina dura

Answer 10

Greenstein

• The composition is the same as the bone surrounding it and does not have a higher mineral content
• The presence or absence of crestal lamina dura was not related to the presence or absence of inflammation/BOP/PD/LOA There is much higher agreement on the absence of LD (89%) compared to the presence of LD (24%)

Question 11

What is the most common bony defect in periodontitis patients?

Answer 11

Manson

Interdental crater, which makes up 1/3 of all defects and 2/3 of all mandibular defects
The maxilla has a greater diversity of defects than the mandible

Question 12

Which wall is higher in craters? Lingual or buccal?

Answer 12

Tal - Lingual 84%

Question 13

Were are periodontal defects most common? What type of defect?

Answer 13

Vrotsos

Posterior > anterior. More craters posterior b/c greater B/L width

Posterior mandible > posterior maxilla

Crater 59%
3-wall 17%

Question 14

How does interproximal distance of roots affect intrabony pockets?

Answer 14

Tal

<2.6mm - horizontal
2.6-3.1mm - 1 vertical
>3.1mm - 2 vertical

Question 15

What is the range of Waerhaug’s sphere of influence?

Answer 15

0.5-2.7mm

Average 1.6mm

Question 16

What are the two fibroblast lineages? How are they different?

Answer 16

Mariotti

PDL and gingival FB

Gingival covers a wound faster, greater non-collagen synthesis and DNA

PDL fibroblasts greater collagen synthesis.

Important for GTR. Exclude gingival FB.

Question 17

What is the width of the PDL? How was it studied? Differences between groups?

Answer 17

Coolidge 1937

Human cadaver block sections

Thickness 0.15-0.2mm

Young - more cellular and wider
Older - decreased collagen turnover

Question 18

What affects the PDL space radiographically?

Answer 18

Van der Linden

INCREASED - increased root radius, exposure time, and dark X-RAY

DECREASED - Increased kVP, horizontal angulation

Question 19

What are fibroblast origins in the PDL?

Answer 19

McCulloch

Tooth side : ectomesenchyme of dental papilla/follicle

Bone side: Perivascular mesenchyme

Question 20

What tissue types are between roots, depending on the width?

Answer 20

Heins & Weider

<0.3 - PDL
0.3-0.5 - PDL + cortical
>0.5 - Cancellous + cortical

Question 21

Who had a counterargument to Greenstein regarding crestal lamina dura?

Answer 21

Rams 2018

In a 2 year retrospective follow-up of treated ChP patients, a crestal lamina dura in angular or horizontal defects was associated w/ clinical periodontal stability up to 24 months.

Rams was retrospective and treated periodontitis patients.

Question 22

Is the maxillary tuberosity a good site to harvest autogenous bone?

Answer 22

Gapski

NO. Sparse cancellous bone. 24% vital bone. Surface bone thin and lamellar

Question 23

Are facial overlay grafts effective?

Answer 23

Poulias

YES - with ridge preservation + Bio-Oss facial overlay graft, lose only 0.3mm width and maintain a flat to convex contour of bone

Question 24

How much of a ridge is lost without ridge preservation?

Answer 24

Van der Weijden

3. 87mm width
4. 67mm buccal
5. 03mm lingual

Schropp

50% ridge width, 2/3 in first 3 months (molars and premolars)

Question 25

Describe the human histologic sequence of healing extraction sockets?

Answer 25

Amler

0: Clot
2-3: Fibrin organization
4: Epithelialization 
7: Replace clot w/ granulation tissue. Osteoid at base of socket
12: Downgrowth of epithelium into socket
20: Replace granulation tissue w/ CT. Osteoid calcifies
21: Bone development begins
24-35: Fusion of epithelium
40: 2/3 socket filled

Cardaropoli did DOGS

Question 26

Describe the different cell types during healing

Answer 26

Trombelli

First 8 weeks: Vascular
Osteoblasts peak at 6-8 weeks and remain constant
Macrophages 2-4 weeks
Minimal osteoclasts