Trauma from Occlusion

Trauma from occlusion refers to the injury sustained by periodontal tissues when occlusal forces exceed their adaptive capacity.

1. Trauma from Occlusion

• This term describes the injury that occurs to periodontal tissues when the forces exerted during occlusion (the contact between opposing teeth) exceed the ability of those tissues to adapt.
• Traumatic Occlusion: An occlusion that produces such injury is referred to as a traumatic occlusion. This can result from various factors, including malocclusion, excessive occlusal forces, or parafunctional habits (e.g., bruxism).

2. Clinical Signs of Trauma to the Periodontium

The most common clinical sign of trauma to the periodontium is:

• Increased Tooth Mobility: As the periodontal tissues are subjected to excessive forces, they may become compromised, leading to increased mobility of the affected teeth. This is often one of the first observable signs of trauma from occlusion.

3. Radiographic Signs of Trauma from Occlusion

Radiographic examination can reveal several signs indicative of trauma from occlusion:

1. Increased Width of Periodontal Space:

   • The periodontal ligament space may appear wider on radiographs due to the increased forces acting on the tooth, leading to a loss of attachment and bone support.

2. Vertical Destruction of Inter-Dental Septum:

   • Trauma from occlusion can lead to vertical bone loss in the inter-dental septa, which may be visible on radiographs as a reduction in bone height between adjacent teeth.

3. Radiolucency and Condensation of the Alveolar Bone:

   • Areas of radiolucency may indicate bone loss, while areas of increased radiopacity (condensation) can suggest reactive changes in the bone due to the stress of occlusal forces.

4. Root Resorption:

   • In severe cases, trauma from occlusion can lead to root resorption, which may be observed as a loss of root structure on radiographs.

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.

Dark Field Microscopy in Periodontal Microbiology

Dark field microscopy and phase contrast microscopy are valuable techniques in microbiological studies, particularly in the field of periodontal research. These methods allow for the direct observation of bacteria in plaque samples, providing insights into their morphology and motility. This lecture will discuss the principles of dark field microscopy, its applications in periodontal disease assessment, and its limitations.

Dark Field Microscopy

• Definition: Dark field microscopy is a technique that enhances the contrast of unstained, transparent specimens, allowing for the visualization of live microorganisms in their natural state.
• Principle: The method uses a special condenser that directs light at an angle, creating a dark background against which the specimen appears bright. This allows for the observation of motility and morphology without the need for staining.

Applications in Periodontal Microbiology

1. Alternative to Culture Methods:

   • Dark field microscopy has been suggested as a rapid alternative to traditional culture methods for assessing bacterial populations in periodontal plaque samples. It allows for immediate observation of bacteria without the time-consuming process of culturing.

2. Assessment of Morphology and Motility:

   • The technique enables direct and rapid assessment of the morphology (shape and structure) and motility (movement) of bacteria present in plaque samples. This information can be crucial for understanding the dynamics of periodontal disease.

3. Indication of Periodontal Disease Status:

   • Dark field microscopy has been used to indicate the status of periodontal disease and the effectiveness of maintenance programs. By observing the presence and activity of specific bacteria, clinicians can gain insights into the health of periodontal tissues.

Limitations of Dark Field Microscopy

1. Analysis of Major Periodontal Pathogens:

   • While dark field microscopy can visualize motile bacteria, it is important to note that many major periodontal pathogens, such as Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Eikenella corrodens, and Eubacterium species, are motile. However, the technique may not provide detailed information about their specific characteristics or pathogenic potential.

2. Differentiation of Treponema Species:

   • Dark field microscopy cannot differentiate between species of Treponema, which is a limitation when identifying specific pathogens associated with periodontal disease. This lack of specificity can hinder the ability to tailor treatment based on the exact microbial profile.

3. Limited Quantitative Analysis:

   • While dark field microscopy allows for qualitative observations, it may not provide quantitative data on bacterial populations, which can be important for assessing disease severity and treatment outcomes.

Periodontal Bone Grafts

Bone grafting is a critical procedure in periodontal surgery, aimed at restoring lost bone and supporting the regeneration of periodontal tissues.

1. Bone Blend

 Bone blend is a mixture of cortical or cancellous bone that is procured using a trephine or rongeurs, placed in an amalgam capsule, and triturated to achieve a slushy osseous mass. This technique allows for the creation of smaller particle sizes, which enhances resorption and replacement with host bone.

Particle Size: The ideal particle size for bone blend is approximately 210 x 105 micrometers.

Rationale: Smaller particle sizes improve the chances of resorption and integration with the host bone, making the graft more effective.

2. Types of Periodontal Bone Grafts

A. Autogenous Grafts

Autogenous grafts are harvested from the patient’s own body, providing the best compatibility and healing potential.

1. Cortical Bone Chips

   • History: First used by Nabers and O'Leary in 1965.
   • Characteristics: Composed of shavings of cortical bone removed during osteoplasty and ostectomy from intraoral sites.
   • Challenges: Larger particle sizes can complicate placement and handling, and there is a potential for sequestration. This method has largely been replaced by autogenous osseous coagulum and bone blend.

2. Osseous Coagulum and Bone Blend

   • Technique: Intraoral bone is obtained using high- or low-speed round burs and mixed with blood to form an osseous coagulum (Robinson, 1969).
   • Advantages: Overcomes disadvantages of cortical bone chips, such as inability to aspirate during collection and variability in quality and quantity of collected bone.
   • Applications: Used in various periodontal procedures to enhance healing and regeneration.

3. Intraoral Cancellous Bone and Marrow

   • Sources: Healing bony wounds, extraction sockets, edentulous ridges, mandibular retromolar areas, and maxillary tuberosity.
   • Applications: Provides a rich source of osteogenic cells and growth factors for bone regeneration.

4. Extraoral Cancellous Bone and Marrow

   • Sources: Obtained from the anterior or posterior iliac crest.
   • Advantages: Generally offers the greatest potential for new bone growth due to the abundance of cancellous bone and marrow.

B. Bone Allografts

Bone allografts are harvested from donors and can be classified into three main types:

1. Undermineralized Freeze-Dried Bone Allograft (FDBA)

   • Introduction: Introduced in 1976 by Mellonig et al.
   • Process: Freeze drying removes approximately 95% of the water from bone, preserving morphology, solubility, and chemical integrity while reducing antigenicity.
   • Efficacy: FDBA combined with autogenous bone is more effective than FDBA alone, particularly in treating furcation involvements.

2. Demineralized (Decalcified) FDBA

   • Mechanism: Demineralization enhances osteogenic potential by exposing bone morphogenetic proteins (BMPs) in the bone matrix.
   • Osteoinduction vs. Osteoconduction: Demineralized grafts induce new bone formation (osteoinduction), while undermineralized allografts facilitate bone growth by providing a scaffold (osteoconduction).

3. Frozen Iliac Cancellous Bone and Marrow

   • Usage: Used sparingly due to variability in outcomes and potential complications.

Comparison of Allografts and Alloplasts

• Clinical Outcomes: Both FDBA and DFDBA have been compared to porous particulate hydroxyapatite, showing little difference in post-treatment clinical parameters.
• Histological Healing: Grafts of DFDBA typically heal with regeneration of the periodontium, while synthetic bone grafts (alloplasts) heal by repair, which may not restore the original periodontal architecture.

Microbes in Periodontics

Bacteria Associated with Periodontal Health

• Primary Species:

  • Gram-Positive Facultative Bacteria:
    • Streptococcus:
      • S. sanguis
      • S. mitis
      • A. viscosus
      • A. naeslundii
    • Actinomyces:
      • Beneficial for maintaining periodontal health.

• Protective or Beneficial Bacteria:

  • Key Species:
    • S. sanguis
    • Veillonella parvula
    • Corynebacterium ochracea
  • Characteristics:
    • Found in higher numbers at inactive periodontal sites (no attachment loss).
    • Low numbers at sites with active periodontal destruction.
    • Prevent colonization of pathogenic microorganisms (e.g., S. sanguis produces peroxide).

• Clinical Relevance:

  • High levels of C. ochracea and S. sanguis are associated with greater attachment gain post-therapy.

Microbiology of Chronic Plaque-Induced Gingivitis

• Composition:

  • Roughly equal proportions of:
    • Gram-Positive: 56%
    • Gram-Negative: 44%
    • Facultative: 59%
    • Anaerobic: 41%

• Predominant Gram-Positive Species:

  • S. sanguis
  • S. mitis
  • S. intermedius
  • S. oralis
  • A. viscosus
  • A. naeslundii
  • Peptostreptococcus micros

• Predominant Gram-Negative Species:

  • Fusobacterium nucleatum
  • Porphyromonas intermedia
  • Veillonella parvula
  • Haemophilus spp.
  • Capnocytophaga spp.
  • Campylobacter spp.

• Pregnancy-Associated Gingivitis:

  • Increased levels of steroid hormones and P. intermedia.

Chronic Periodontitis

• Key Microbial Species:

  • High levels of:
    • Porphyromonas gingivalis
    • Bacteroides forsythus
    • Porphyromonas intermedia
    • Campylobacter rectus
    • Eikenella corrodens
    • Fusobacterium nucleatum
    • Actinobacillus actinomycetemcomitans
    • Peptostreptococcus micros
    • Treponema spp.
    • Eubacterium spp.

• Pathogenic Mechanisms:

  • P. gingivalis and A. actinomycetemcomitans can invade host tissue cells.
  • Viruses such as Epstein-Barr Virus-1 (EBV-1) and human cytomegalovirus (HCMV) may contribute to bone loss.

Localized Aggressive Periodontitis

• Microbiota Characteristics:
  • Predominantly gram-negative, capnophilic, and anaerobic rods.
  • Almost all localized juvenile periodontitis (LJP) sites harbor A. actinomycetemcomitans, which can comprise up to 90% of the total cultivable microbiota.

Flossing Technique

Flossing is an essential part of oral hygiene that helps remove plaque and food particles from between the teeth and along the gumline, areas that toothbrushes may not effectively clean. Proper flossing technique is crucial for maintaining gum health and preventing cavities.

Flossing Technique

1. Preparation:

   • Length of Floss: Take 12 to 18 inches of dental floss. This length allows for adequate maneuverability and ensures that you can use a clean section of floss for each tooth.
   • Grasping the Floss: Hold the floss taut between your hands, leaving a couple of inches of floss between your fingers. This tension helps control the floss as you maneuver it between your teeth.

2. Inserting the Floss:

   • Slip Between Teeth: Gently slide the floss between your teeth. Be careful not to snap the floss, as this can cause trauma to the gums.
   • Positioning: Insert the floss into the area between your teeth and gums as far as it will comfortably go, ensuring that you reach the gumline.

3. Flossing Motion:

   • Vertical Strokes: Use 8 to 10 vertical strokes with the floss to dislodge food particles and plaque. Move the floss up and down against the sides of each tooth, making sure to clean both the front and back surfaces.
   • C-Shaped Motion: For optimal cleaning, wrap the floss around the tooth in a C-shape and gently slide it beneath the gumline.

4. Frequency:

   • Daily Flossing: Aim to floss at least once a day. Consistency is key to maintaining good oral hygiene.
   • Best Time to Floss: The most important time to floss is before going to bed, as this helps remove debris and plaque that can accumulate throughout the day.

5. Flossing and Brushing:

   • Order of Operations: Flossing can be done either before or after brushing your teeth. Both methods are effective, so choose the one that fits best into your routine.