Talk to us?

Periodontics - NEETMDS- courses
NEET MDS Lessons
General Medicine

Classification of Cementum According to Schroeder

Cementum is a specialized calcified tissue that covers the roots of teeth and plays a crucial role in periodontal health. According to Schroeder, cementum can be classified into several distinct types based on its cellular composition and structural characteristics. Understanding these classifications is essential for dental professionals in diagnosing and treating periodontal conditions.

Classification of Cementum

  1. Acellular Afibrillar Cementum:

    • Characteristics:
      • Contains neither cells nor collagen fibers.
      • Present in the coronal region of the tooth.
      • Thickness ranges from 1 µm to 15 µm.
    • Function:
      • This type of cementum is thought to play a role in the attachment of the gingiva to the tooth surface.

  2. Acellular Extrinsic Fiber Cementum:

    • Characteristics:
      • Lacks cells but contains closely packed bundles of Sharpey’s fibers, which are collagen fibers that anchor the cementum to the periodontal ligament.
      • Typically found in the cervical third of the roots.
      • Thickness ranges from 30 µm to 230 µm.
    • Function:
      • Provides strong attachment of the periodontal ligament to the tooth, contributing to the stability of the tooth in its socket.

  3. Cellular Mixed Stratified Cementum:

    • Characteristics:
      • Contains both extrinsic and intrinsic fibers and may contain cells.
      • Found in the apical third of the roots, at the apices, and in furcation areas.
      • Thickness ranges from 100 µm to 1000 µm.
    • Function:
      • This type of cementum is involved in the repair and adaptation of the tooth root, especially in response to functional demands and periodontal disease.

  4. Cellular Intrinsic Fiber Cementum:

    • Characteristics:
      • Contains cells but no extrinsic collagen fibers.
      • Primarily fills resorption lacunae, which are areas where cementum has been resorbed.
    • Function:
      • Plays a role in the repair of cementum and may be involved in the response to periodontal disease.

  5. Intermediate Cementum:

    • Characteristics:
      • A poorly defined zone located near the cementoenamel junction (CEJ) of certain teeth.
      • Appears to contain cellular remnants of the Hertwig's epithelial root sheath (HERS) embedded in a calcified ground substance.
    • Function:
      • Its exact role is not fully understood, but it may be involved in the transition between enamel and cementum.

Clinical Significance

  • Importance of Cementum:

    • Understanding the different types of cementum is crucial for diagnosing periodontal diseases and planning treatment strategies.
    • The presence of various types of cementum can influence the response of periodontal tissues to disease and trauma.

  • Cementum in Periodontal Disease:

    • Changes in the thickness and composition of cementum can occur in response to periodontal disease, affecting tooth stability and attachment.

Dental Plaque

Dental plaque is a biofilm that forms on the surfaces of teeth and is composed of a diverse community of microorganisms. The development of dental plaque occurs in stages, beginning with primary colonizers and progressing to secondary colonization and plaque maturation.

Primary Colonizers

  • Timeframe:
    • Acquired within a few hours after tooth cleaning or exposure.
  • Characteristics:
    • Predominantly gram-positive facultative microbes.
  • Key Species:
    • Actinomyces viscosus
    • Streptococcus sanguis
  • Adhesion Mechanism:
    • Primary colonizers adhere to the tooth surface through specific adhesins.
    • For example, A. viscosus possesses fimbriae that bind to proline-rich proteins in the dental pellicle, facilitating initial attachment.

Secondary Colonization and Plaque Maturation

  • Microbial Composition:
    • As plaque matures, it becomes predominantly populated by gram-negative anaerobic microorganisms.
  • Key Species:
    • Prevotella intermedia
    • Prevotella loescheii
    • Capnocytophaga spp.
    • Fusobacterium nucleatum
    • Porphyromonas gingivalis
  • Coaggregation:
    • Coaggregation refers to the ability of different species and genera of plaque microorganisms to adhere to one another.
    • This process occurs primarily through highly specific stereochemical interactions of protein and carbohydrate molecules on cell surfaces, along with hydrophobic, electrostatic, and van der Waals forces.

Plaque Hypotheses

  1. Specific Plaque Hypothesis:

    • This hypothesis posits that only certain types of plaque are pathogenic.
    • The pathogenicity of plaque depends on the presence or increase of specific microorganisms.
    • It predicts that plaque harboring specific bacterial pathogens leads to periodontal disease due to the production of substances that mediate the destruction of host tissues.

  2. Nonspecific Plaque Hypothesis:

    • This hypothesis maintains that periodontal disease results from the overall activity of the entire plaque microflora.
    • It suggests that the elaboration of noxious products by the entire microbial community contributes to periodontal disease, rather than specific pathogens alone.

Disorder Feature
Diabetes + HTN Avoid thiazides
ACE inhibitors Risk of hyperkalemia
SIADH Hyponatremia; often in small cell lung cancer
Hypothyroidism ↓ Alk Phosphatase
Acromegaly ↑ GH; check IGF-1 levels
Addison’s Hypotension, hyperpigmentation

🔁 Pulse Patterns

Pulse Type Condition
Slow rising pulse Aortic stenosis (AS)
Pulsus alternans CHF
Pulsus bigeminus Digoxin therapy
Pulsus paradoxus Tamponade, pericarditis, asthma
Water hammer pulse Aortic regurgitation
Pulsus bisferiens Best felt in radial artery

🔊 Heart Sounds

  • Loud S1: Short PR interval, tachycardia, mitral stenosis
  • Fourth Heart Sound (S4): Heard during ventricular filling
  • Opening snap: High-pitched, diastolic sound

  • Blood transfusion: Always consider FNHTR first for fever during transfusion
  • G6PD deficiency: Heinz bodies are pathognomonic; estrogen is safe
  • BMT infections: HSV earliest, interstitial pneumonitis at 7 weeks
  • Prevention: Patient education and prophylaxis are crucial in all three conditions

Feature Details
First valvular lesion Mitral regurgitation
Commonest valve Mitral (especially in children)
Minor criteria Fever (Modified Jones Criteria)
Subcutaneous nodules Non-tender, extensor surfaces
Erythema marginatum Associated with carditis
Diagnostic marker Aschoff's nodule
McCallum's patch Rheumatic endocarditis indicator

Blade Angulation Protocols

Scaling & Root Planing

  • Angulation: 45-90 degrees to tooth surface
  • Purpose: Effective calculus removal and root surface debridement

Gingival Curettage

  • Angulation: >90 degrees
  • Technique: Removal of infected soft tissue from pocket wall

Curette Sharpening

  • Optimal Angle: 100-110 degrees
  • Maintenance: Critical for effective instrumentation

Curette Design

Gracey Curettes

  • Offset Angle: 60 degrees
  • Specificity: Area-specific design for different tooth surfaces

Universal Curettes

  • Angle: 90 degrees
  • Application: Suitable for all tooth surfaces

After-Five Curettes

  • Modification: Terminal shank extended by 3mm
  • Purpose: Access to deep pockets (>5mm)

Probing Systems

CPITN Probe

  • Tip Diameter: 0.5mm
  • Markings: 3.5, 5.5, 8.5, 11.5mm
  • Use: Community periodontal index assessment

Florida Probe

  • Tip Diameter: 0.4mm (more precise)
  • Technology: Computerized probing system

Implant Probing

  • Maximum Force: 25N
  • Probe Type: Plastic probes recommended to prevent implant surface damage
MDS SUBJECTS

Explore by Exams

INI CET
AIIMS , PGIMER
INBDE
United States
NDEB
Canada
ADC
Australia
PSC
State Dental Jobs
SDLE
Saudi Dental
ADC
Army Dental Corps
ORE
UK Dentist