Cementum Clinical Correlation Quiz

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Questions and Answers

What is the primary role of the cemento-dentinal junction?

To facilitate the movement of nerves into the tooth

To separate dentin from enamel

To regulate blood supply to the tooth

To serve as a medium for collagen fiber attachment (correct)

How does the width of the cemento-dentinal junction change with age?

It decreases over time

It fluctuates with dental health

It increases significantly

It remains relatively stable (correct)

What is a key feature of intermediate cementum?

It contains characteristic features of dentin

It contains cellular remnants of Hertwig’s epithelial root sheath (correct)

It is predominantly found in incisors

It is a well-defined zone at the cemento-dentinal junction

What function does cementum provide at the surface of sensitive root dentin?

Sealing the surface Signup and view all the answers

What aspect does continuous deposition of cementum facilitate?

Adjusting to tooth movement Signup and view all the answers

Which type of cementum is primarily responsible for the repair of the root surface?

Secondary cementum Signup and view all the answers

What characterizes anatomic repair of cementum?

Former outline is re-established Signup and view all the answers

What type of cemental resorption is characterized by its origin from within the tooth structure?

Internal cemental resorption Signup and view all the answers

Cementum is more resistant to resorption than which of the following?

Bone Signup and view all the answers

Which of the following is a local factor that can lead to cementum resorption?

Excessive orthodontic force Signup and view all the answers

What happens to the periodontal ligament (PDL) space during functional repair?

It is restored to normal width. Signup and view all the answers

Which of the following systemic factors is associated with cementum resorption?

Hypophosphatasia Signup and view all the answers

What is a key reason for cementum's resistance to resorption compared to bone?

Cementum is avascular and has slow metabolism. Signup and view all the answers

What is the primary role of the enzyme associated with the ALPL gene?

Ensuring bone and dental mineralization Signup and view all the answers

Which of the following is a common oral sign of hypophosphatasia?

Premature tooth loss Signup and view all the answers

Which treatment is NOT typically used for managing hypophosphatasia?

High-dose chemotherapy Signup and view all the answers

What is the hallmark radiographic finding in Paget disease?

Cotton wool appearance of paget’s bone Signup and view all the answers

Which of the following conditions is characterized by overgrowth of body parts in children?

Hyperpituitarism Signup and view all the answers

What type of bone involvement is primarily associated with Paget disease?

Enhanced bone resorption Signup and view all the answers

Which clinical feature is typically associated with acromegaly?

Prognathic mandible Signup and view all the answers

Which of the following statements about hypercementosis is correct?

It is an excessive deposition of cementum on tooth roots Signup and view all the answers

Which benign neoplasm is characterized by a large mass of cementum or cementum-like tissue on the tooth root?

Cementoblastoma Signup and view all the answers

At what age is Cementoblastoma most commonly diagnosed?

Under 25 years Signup and view all the answers

Which site is most commonly affected by Cementifying fibroma?

Mandibular premolar and molar area Signup and view all the answers

What is the primary treatment for a well-defined Cementoblastoma?

Enucleation of the tumor Signup and view all the answers

How can excessive removal of healthy cementum during root planning affect periodontal health?

Leads to tooth mobility or loss Signup and view all the answers

What characterizes the radiographic finding of Cementoblastoma?

Dense radio-opaque mass with a thin radiolucent line Signup and view all the answers

Cementifying fibroma is primarily composed of which types of tissue?

A mixture of fibrous tissue and bony trabeculae Signup and view all the answers

In which population is Cementifying fibroma most frequently diagnosed?

Adults in their 30s and 40s Signup and view all the answers

What is the primary function of cementum?

Anchoring teeth to the bone via periodontal ligament Signup and view all the answers

What describes the cellular composition of acellular cementum?

Contains no cells Signup and view all the answers

Which type of cementum forms after a tooth reaches the occlusal plane?

Cellular cementum Signup and view all the answers

What is the thickness range of the thinnest part of cementum?

20-50 µm Signup and view all the answers

What is the primary inorganic component of cementum?

Hydroxyapatite crystals Signup and view all the answers

How does the permeability of cellular cementum compare to acellular cementum?

Cellular cementum is more permeable Signup and view all the answers

What distinguishes acellular afibrillar cementum from other types?

Lack of cells and fibers Signup and view all the answers

What type of fibers does cellular mixed stratified cementum predominantly contain?

Both intrinsic and extrinsic fibers Signup and view all the answers

What significant role does the cemento-enamel junction play in dental health?

It serves as a reference point for attachment levels Signup and view all the answers

Which type of cementum is characterized by regular formation and high calcification?

Acellular cementum Signup and view all the answers

What happens to the permeability of cementum with age?

It decreases over time Signup and view all the answers

Which cementum type forms primarily in the cervical third thickness of the tooth?

Acellular extrinsic fiber cementum Signup and view all the answers

How does the rate of formation differ between acellular and cellular cementum?

Cellular cementum forms faster Signup and view all the answers

What is the primary purpose of Guided Tissue Regeneration (GTR)?

To stimulate new formation of cementum, periodontal ligament, and bone. Signup and view all the answers

Which factor primarily contributes to tooth sensitivity related to cementum?

Exposed cementum due to gingival recession. Signup and view all the answers

What is a common method to reduce tooth sensitivity caused by exposed cementum?

Covering with protective composite resin or glass ionomer restorations. Signup and view all the answers

Which of the following agents is not known to block the dentinal tubule to reduce sensitivity?

Baking Soda Signup and view all the answers

Which statement accurately describes the role of cementum in dental health?

Cementum aids in the attachment and stability of teeth. Signup and view all the answers

What happens when gingiva recedes and cementum is exposed?

Sensitivity increases and the risk of root caries heightens. Signup and view all the answers

What surgical option may be performed for severe cases of gum recession?

Connective tissue or free gingival grafting. Signup and view all the answers

Which of the following issues can arise due to irreversible damage to cementum?

Permanent loss of tooth support and increased dental decay. Signup and view all the answers

Study Notes

Cementum is the calcified avascular mesenchymal tissue forming the outer layer of root surfaces.
It begins at the cemento-enamel junction (CEJ) and continues to the apex.
Cementum is part of the periodontium apparatus.
It plays a key role in anchoring teeth to the bone via the periodontal ligament.

Introduction
Structures of cementum
Function
Developmental anomalies
Systemic conditions that influence cementum
Clinical application

What is Cementum?

Hardness is less than dentin.
Color: light yellow, distinguishable from enamel (darker hue) and dentin (lighter).
Thinnest at the cemento-enamel junction (20-50 µm), thickest towards the apex (150-200 µm).
Cellular cementum permeability is greater than acellular cementum (more permeable from dentin and PDL side).
With age, this permeability decreases.

Composition

Primarily composed of organic and inorganic materials (50-55% organic, 45-50% inorganic).
Inorganic component: calcium phosphate in the form of hydroxyapatite crystals.
Organic component: collagen protein and polysaccharides (mainly collagen type I & III).
Main collagen sources: Sharpey's fibers (extrinsic), and intrinsic fibers in the cementum matrix, both produced by fibroblasts.

Classification of Cementum

Based on location: coronal or radicular.
Based on cellularity: cellular or acellular.
Based on fibers: extrinsic or intrinsic.

Acellular and Cellular Cementum

Feature	Acellular Cementum (Primary)	Cellular Cementum (Secondary)
Formation	Before tooth reaches occlusal plane	Forms after tooth reaches occlusal plane
Cells	No cells	Contains cementocytes
Location	Cervical or half of root	Apical portion
Rate of formation	Slow	Faster
Calcification	More calcified	Less calcified
Fibers	Sharpey's fibers	Less fibers
Regularity	Regular	Irregular
Thickness	30-50 µm	1 to several µm
Function	Anchorage and attachment to PDL	Contribute to root length during growth, repair, and regeneration

Presence or Absence of Fibers

Fibrillar cementum: contains densely packed collagen fibrils.
Afibrillar cementum: lacks dense collagen fibers.
Categorized further as acellular afibrillar, acellular intrinsic fiber cementum, acellular extrinsic fibers, cellular mixed stratified cementum, and cellular intrinsic fiber cementum.

Structures in Cementum

Cemento-enamel junction (CEJ): the junction between enamel and cementum.
- Types: overlapping, edge-to-edge, and gap.
Clinical significance of CEJ: reference point for healthy individuals, calculate clinical attachment loss, & determine progression of periodontal disease.
Cemento-dentinal junction (CDJ): the terminal apical area where cementum joins internal root canal dentin.
- Clinical significance: attachment medium for collagen fibers to alveolar bone, major source of repair for root surfaces.

Intermediate Cementum

Thin layer of hard tissue between cementum and dentin.
Contains cellular remnants of Hertwig's epithelial root sheath.
Predominantly seen in the apical two-thirds of molars and premolars.
Does not exhibit the characteristics of dentin or cementum.
Function: seals the surface of sensitive root dentin, attachment of cementum to dentin.

Function of Cementum

Anchorage: Provides a medium for collagen fiber attachment, binding the tooth to the alveolar bone.
Adaptation: Continuous cementum deposition adapts to tooth movement, maintaining vertical dimensions.
Repair: Secondary (cellular) cementum responsible for repair and maintaining root surface integrity.
- Two types of repair: anatomic and functional.

Cementum Resorption

Local Factors: Cysts, tumors, embedded teeth, trauma from occlusion, excessive orthodontic force, periapical or periodontal disease.
Systemic Factors: Paget's disease, hypophosphatasia, calcium deficiency.

Cementum Resorption & Orthodontic Tooth Movement

Cementum is more resistant to resorption than bone.
Differences in vascularization & metabolism between cementum and bone affect resistance to pressure.
Surface layers of cementum have higher fluoride content, leading to greater resistance to acidic dissolution.
Bone resorption occurs on the pressure side and bone formation on the tension side during tooth movement.

Age Changes

Cementum deposition is continuous throughout life, but slower in older age, particularly in the apical areas.
Permeability decreases with age.
Surface becomes irregular due to calcification.

Developmental Anomalies

Hypercementosis: Thickening of cementum, potentially localized or generalized.
- Causes: teeth without antagonists, pulpal or periodontal infections.
- Clinical features: vital teeth insensitive to percussion, generalized thickening with nodular enlargement, large apical third roots, potential spikes.
- Radiographic appearance: thickened and dulled roots, apex rounding.
- Management: hypercementosis itself does not require treatment. Focus on the primary etiology, consider extraction / sectioning if needed.
Cemental Tear: Detachment of cementum fragment.
- Etiology: acute trauma from occlusion.
- Clinical significance: a contributing factor to adult periodontitis.
Cementicles: Globular mass of cellular cementum, less than 0.05mm.
- Types: free, sessile/attached, interstitial/embedded.
Ankylosis: Fusion of cementum and alveolar bone.
- Etiology: chronic periapical infection, tooth reimplantation, and occlusal trauma.
- Clinical presentation: lack of physiological mobility, metallic sound upon percussion, infraocclusion, and radiographic appearance of bone filling the PDL space. No specific treatment.
Concrescence: Fusion of teeth by cementum fusion.
- Etiology: traumatic injury, crowding of teeth during maturation.

Systemic Conditions Influencing Cementum

Hypophosphatasia: Rare inherited metabolic disorder causing mutations in the ALPL gene, leading to deficient TNSALP activity, interfering with hydroxyapatite crystal formation.
- Oral signs (premature tooth loss, dental hypoplasia, alveolar bone deficiency) often precede skeletal symptoms.
- Treatment: enzyme replacement therapy, pain relief (NSAIDs), physical therapy, dental care (fluoride treatment, sealants), and prosthetics/implants, vitamin D & calcium supplements, and lifestyle modifications,
Paget's Disease: Characterized by enhanced bone resorption.
- Clinical features: predominantly affecting middle-aged adults, involvement of facial bones (maxilla and mandible), widening of alveolar ridge, and loosening of teeth.
- Characteristic radiographic appearance: cotton-wool appearance of bone, generalized hypercementosis of teeth.
- Histologic appearance: jigsaw or mosaic pattern.

Clinical Importance and Applications

Cementum and Periodontal Health: Root planning and scaling to remove calculus and infected or roughened cementum. Guided tissue regeneration uses barriers/growth factors to stimulate new cementum and periodontal ligament.
Cementum and Tooth Sensitivity: Gingival recession, exposing cementum, can lead to tooth sensitivity. Desensitizing agents (potassium nitrate, fluoride compounds) can address this.
Restorative Procedures: Covering exposed cementum with composite resin can protect the root surface.
Soft Tissue Grafting: May be needed for severe gingival recession to cover exposed cementum.

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Description

Test your knowledge on cementum, the calcified tissue forming the outer layer of tooth roots. This quiz covers its structures, functions, developmental anomalies, and the clinical implications of cementum in dental practice. Dive into the essential aspects of cementum and its role in the periodontium.