Finger Rests in Dental Instrumentation

Use of finger rests is essential for providing stability and control during procedures. A proper finger rest allows for more precise movements and reduces the risk of hand fatigue.

Importance of Finger Rests

• Stabilization: Finger rests serve to stabilize the hand and the instrument, providing a firm fulcrum that enhances control during procedures.
• Precision: A stable finger rest allows for more accurate instrumentation, which is crucial for effective treatment and patient safety.
• Reduced Fatigue: By providing support, finger rests help reduce hand and wrist fatigue, allowing the clinician to work more comfortably for extended periods.

Types of Finger Rests

1. Conventional Finger Rest:

   • Description: The finger rest is established on the tooth surfaces immediately adjacent to the working area.
   • Application: This is the most common type of finger rest, providing direct support for the hand while working on a specific tooth. It allows for precise movements and control during instrumentation.

2. Cross Arch Finger Rest:

   • Description: The finger rest is established on the tooth surfaces on the other side of the same arch.
   • Application: This technique is useful when working on teeth that are not directly adjacent to the finger rest. It provides stability while allowing access to the working area from a different angle.

3. Opposite Arch Finger Rest:

   • Description: The finger rest is established on the tooth surfaces of the opposite arch (e.g., using a mandibular arch finger rest for instrumentation on the maxillary arch).
   • Application: This type of finger rest is particularly beneficial when accessing the maxillary teeth from the mandibular arch, providing a stable fulcrum while maintaining visibility and access.

4. Finger on Finger Rest:

   • Description: The finger rest is established on the index finger or thumb of the non-operating hand.
   • Application: This technique is often used in areas where traditional finger rests are difficult to establish, such as in the posterior regions of the mouth. It allows for flexibility and adaptability in positioning.

Aggressive Periodontitis (formerly Juvenile Periodontitis)

• Historical Names: Previously referred to as periodontosis, deep cementopathia, diseases of eruption, Gottleib’s diseases, and periodontitis marginalis progressive.
• Risk Factors:
  • High frequency of Actinobacillus actinomycetemcomitans.
  • Immune defects (functional defects of PMNs and monocytes).
  • Autoimmunity and genetic factors.
  • Environmental factors, including smoking.
• Clinical Features:
  • Vertical loss of alveolar bone around the first molars and incisors, typically beginning around puberty.
  • Bone loss patterns often described as "target" or "bull" shaped lesions.

Dimensions of Toothbrushes

Toothbrushes play a crucial role in maintaining oral hygiene, and their design can significantly impact their effectiveness. The American Dental Association (ADA) has established guidelines for the dimensions and characteristics of acceptable toothbrushes. This lecture will outline these specifications and discuss their implications for dental health.

Acceptable Dimensions of Toothbrushes

1. Brushing Surface Dimensions:

   • Length:
     • Acceptable brushing surfaces should measure between 1 to 1.25 inches (25.4 to 31.8 mm) long.
   • Width:
     • The width of the brushing surface should range from 5/16 to 3/8 inch (7.9 to 9.5 mm).
   • Rows of Bristles:
     • Toothbrushes should have 2 to 4 rows of bristles to effectively clean the teeth and gums.
   • Tufts per Row:
     • Each row should contain 5 to 12 tufts of bristles, allowing for adequate coverage and cleaning ability.

2. Filament Diameter:

   • The diameter of the bristles can vary, affecting the stiffness and cleaning effectiveness:
     • Soft Filaments:
       • Diameter of 0.2 mm (0.007 inches). Ideal for sensitive gums and children.
     • Medium Filaments:
       • Diameter of 0.3 mm (0.012 inches). Suitable for most adults.
     • Hard Filaments:
       • Diameter of 0.4 mm (0.014 inches). Generally not recommended for daily use as they can be abrasive to the gums and enamel.

3. Filament Stiffness:

   • The stiffness of the bristles is determined by the diameter relative to the length of the filament. Thicker filaments tend to be stiffer, which can affect the brushing technique and comfort.

Special Considerations for Children's Toothbrushes

• Size:
  • Children's toothbrushes are designed to be smaller to accommodate their smaller mouths and teeth.
• Bristle Thickness:
  • The bristles are thinner, measuring 0.005 inches (0.1 mm) in diameter, making them gentler on sensitive gums.
• Bristle Length:
  • The bristles are shorter, typically around 0.344 inches (8.7 mm), to ensure effective cleaning without causing discomfort.

Clinical Implications

1. Choosing the Right Toothbrush:

   • Dental professionals should guide patients in selecting toothbrushes that meet ADA specifications to ensure effective plaque removal and gum protection.
   • Emphasizing the importance of using soft or medium bristles can help prevent gum recession and enamel wear.

2. Education on Brushing Technique:

   • Proper brushing technique is as important as the toothbrush itself. Patients should be educated on how to use their toothbrush effectively, regardless of the type they choose.

3. Regular Replacement:

   • Patients should be advised to replace their toothbrush every 3 to 4 months or sooner if the bristles become frayed. This ensures optimal cleaning effectiveness.

4. Special Considerations for Children:

   • Parents should be encouraged to choose appropriately sized toothbrushes for their children and to supervise brushing to ensure proper technique and effectiveness.

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.

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.

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.