3 - Cementum and GCF Flashcards
What is the average thickness of cementum? Is it thicker coronal or apical? Thicker or thinner with age?
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
What is the arrangement of fibers in acellular and cellular cementum?
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
Where is cellular and acellular cementum found?
Stahl
Acellular - coronal, slow formation
Cellular - apically
What are the differences in fibroblasts and cementoblasts?
Yamasaki
Cementoblasts - less functionally active, more glycogen, less organelles
Fibroblasts - active collagen producing cells
What is the microstructure of the CEJ?
Schroeder
Microundulated, 9-17% longer than the straight perimeter at the same level
Do bacteria penetrate cementum and dentin?
DALY - YES. Up to 12um at sites of overlying plaque
ADRIAENS - In remnants of Sharpey’s fibers and into outer 300um of dental tubules
Who described cemental tears?
Leknes
Should cementum be removed during NST/surgery?
Nyman - NO, similar results when cementum was removed w/ diamond burs and when the root was scaled and polished
Can new cementum form over diseased surfaces?
Middleton and Bowers
YES - cellular cementum forms over periodontally exposed root surfaces and on old cementum/dentin. Results are enhanced when grafted w/ DFDBA
Who first suggested endotoxin (LPS) as being harmful to periodontal cells
Hatfield
Normal and diseased roots incubated w/ epithelial cells. Diseased roots induce degenerative processes
Do gingival fibroblasts attach to diseased roots?
Aleo
NO - BUT attach normally to controls and SRP teeth
Clinical success depends on endotoxin removal
Does LPS adhere strongly to roots?
Nakib - NO. Removed w/ 1 minute of brushing
Moore - NO. Washing removed 40%, brushing removed remaining 60%
Hughes - NO. No remaining LPS after SRP
Describe histologic healing of cementum after GTR
Laurell
Monkey study, 6 months w/ 50% extrinsic fiber density w/ AEFC/CMFC
2 years w/ 85% normal cementum thickness + AEFC/CMFC
Are GCF scores predictive for gingival health?
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
What could we look for in GCF as indicators of disease/health?
Offenbacher - PGE2. 2SD above healthy, 47X CAL
Lamster - B-glucuronidase (granule release from PMNs). Reduced IgA
Giannopoulou - IL-1B, IL-6, IL-8
What is different about DM1 GCF?
Safkan-Seppala
Higher collagenase
What is the function of the cementum? Does it continually form?
Attachment of PDL fibers to the tooth surface
Intermittent deposition w/ resting lines
What is the make-up of cementum?
50% inorganic, 50% organic
61% mineral HA
27% organic matrix
12% water
What collagen makes up cementum?
90% type 1
5% type 3
Trace type 7
What are the cementum associated cells?
Cementoblast - from dental follicle.
Cementocytes - in lacunae, vital cells
Cementoclasts - from bone marrow
PDL fibroblast - make Sharpey’s fibers
What cementum classification do we use?
Schroeder
AAC - enamel and dentin. Unknown function
AEFC - coronal/middle. 40-70% surface. Perpendicular to root.
CMSC - Apical 1/3. Intrinsic fibers.
Describe the anatomy of the CEJ
Thorsen
60-65% cementum overlaps enamel
30% - cementum meets enamel
5-10% - gap
Can cementum form over CEPs?
Blanchard
Mandibular grade 3 CEPs, 45% covered w/ cementum
May form cementum pouches - BACTERIAL NIDUS
What is the prevalence of enamel pearls?
Moskow & Canut
2.69%
MAX 2M/3M
Mean diameter 1.7mm
Describe periapical cemental dysplasia
AKA cementoma
Apices of mandibular anterior/PM
Asymptomatic
Begins as radiolucency and then calcifies w/ a thin radiolucent line
Describe florid osseous dysplasia
Idiopathic in periapical region. Extensive, bilateral in mandible. Middle age black females.
Multiple quadrants
Describe Paget’s disease symptom
Dysregulated bone remodeling. Frontal bossing
Hypercementosis generalized
Describe hypophosphatasia symptom
Absence of cementum
Describe Papillon-Lefevre symptom
Thin cementum
Palmar/plantar hyperkeratosis
Describe Gardner’s syndrome symptoms
Hypercementosis Osteomas Supernumerary Polyposis of large intestine Epidermoid cyst Sebaceous cysts
