3 - Cementum and GCF

Question 1

What is the average thickness of cementum? Is it thicker coronal or apical? Thicker or thinner with age?

Answer 1

Zander

Cementum is deposited continuously and is thickest at apex, thinner at CEJ. The thickness may triple over a lifetime. The average thickness can vary from 0.07-0.2mm

Question 2

What is the arrangement of fibers in acellular and cellular cementum?

Answer 2

Selvig

Acellular cementum is arranged with principal fibers oriented radially with Sharpey’s fibers closely packed and calcified

Cellular cementum Sharpey’s fibers are an irregularly shaped central core surrounded by a calcified peripheral part. Fibers are oriented parallel to the cementum surface and contain lacunae from cementocytes and accessory canals. It resembles alveolar bone and is quickly formed

Question 3

Where is cellular and acellular cementum found?

Answer 3

Stahl

Acellular - coronal, slow formation
Cellular - apically

Question 4

What are the differences in fibroblasts and cementoblasts?

Answer 4

Yamasaki

Cementoblasts - less functionally active, more glycogen, less organelles

Fibroblasts - active collagen producing cells

Question 5

What is the microstructure of the CEJ?

Answer 5

Schroeder

Microundulated, 9-17% longer than the straight perimeter at the same level

Question 6

Do bacteria penetrate cementum and dentin?

Answer 6

DALY - YES. Up to 12um at sites of overlying plaque

ADRIAENS - In remnants of Sharpey’s fibers and into outer 300um of dental tubules

Question 7

Who described cemental tears?

Answer 7

Leknes

Question 8

Should cementum be removed during NST/surgery?

Answer 8

Nyman - NO, similar results when cementum was removed w/ diamond burs and when the root was scaled and polished

Question 9

Can new cementum form over diseased surfaces?

Answer 9

Middleton and Bowers

YES - cellular cementum forms over periodontally exposed root surfaces and on old cementum/dentin. Results are enhanced when grafted w/ DFDBA

Question 10

Who first suggested endotoxin (LPS) as being harmful to periodontal cells

Answer 10

Hatfield

Normal and diseased roots incubated w/ epithelial cells. Diseased roots induce degenerative processes

Question 11

Do gingival fibroblasts attach to diseased roots?

Answer 11

Aleo

NO - BUT attach normally to controls and SRP teeth

Clinical success depends on endotoxin removal

Question 12

Does LPS adhere strongly to roots?

Answer 12

Nakib - NO. Removed w/ 1 minute of brushing

Moore - NO. Washing removed 40%, brushing removed remaining 60%

Hughes - NO. No remaining LPS after SRP

Question 13

Describe histologic healing of cementum after GTR

Answer 13

Laurell

Monkey study, 6 months w/ 50% extrinsic fiber density w/ AEFC/CMFC

2 years w/ 85% normal cementum thickness + AEFC/CMFC

Question 14

Are GCF scores predictive for gingival health?

Answer 14

Orban - NO. Plaque scores but NOT GCF are representative of inflammatory status of gingiva

Hancock - Maybe. GCF is a clinical indicator of presence but not the severity of inflammation

Question 15

What could we look for in GCF as indicators of disease/health?

Answer 15

Offenbacher - PGE2. 2SD above healthy, 47X CAL

Lamster - B-glucuronidase (granule release from PMNs). Reduced IgA

Giannopoulou - IL-1B, IL-6, IL-8

Question 16

What is different about DM1 GCF?

Answer 16

Safkan-Seppala

Higher collagenase

Question 17

What is the function of the cementum? Does it continually form?

Answer 17

Attachment of PDL fibers to the tooth surface

Intermittent deposition w/ resting lines

Question 18

What is the make-up of cementum?

Answer 18

50% inorganic, 50% organic

61% mineral HA
27% organic matrix
12% water

Question 19

What collagen makes up cementum?

Answer 19

90% type 1

5% type 3

Trace type 7

Question 20

What are the cementum associated cells?

Answer 20

Cementoblast - from dental follicle.
Cementocytes - in lacunae, vital cells
Cementoclasts - from bone marrow
PDL fibroblast - make Sharpey’s fibers

Question 21

What cementum classification do we use?

Answer 21

Schroeder

AAC - enamel and dentin. Unknown function
AEFC - coronal/middle. 40-70% surface. Perpendicular to root.
CMSC - Apical 1/3. Intrinsic fibers.

Question 22

Describe the anatomy of the CEJ

Answer 22

Thorsen

60-65% cementum overlaps enamel
30% - cementum meets enamel
5-10% - gap

Question 23

Can cementum form over CEPs?

Answer 23

Blanchard

Mandibular grade 3 CEPs, 45% covered w/ cementum

May form cementum pouches - BACTERIAL NIDUS

Question 24

What is the prevalence of enamel pearls?

Answer 24

Moskow & Canut

2.69%

MAX 2M/3M

Mean diameter 1.7mm

Question 25

Describe periapical cemental dysplasia

Answer 25

AKA cementoma

Apices of mandibular anterior/PM
Asymptomatic
Begins as radiolucency and then calcifies w/ a thin radiolucent line

Question 26

Describe florid osseous dysplasia

Answer 26

Idiopathic in periapical region. Extensive, bilateral in mandible. Middle age black females.

Multiple quadrants

Question 27

Describe Paget’s disease symptom

Answer 27

Dysregulated bone remodeling. Frontal bossing

Hypercementosis generalized

Question 28

Describe hypophosphatasia symptom

Answer 28

Absence of cementum

Question 29

Describe Papillon-Lefevre symptom

Answer 29

Thin cementum

Palmar/plantar hyperkeratosis

Question 30

Describe Gardner’s syndrome symptoms

Answer 30

Hypercementosis 
Osteomas
Supernumerary
Polyposis of large intestine
Epidermoid cyst
Sebaceous cysts