Catgut Sutures

• Composition: Processed animal intestine (usually sheep)
• Degradation mechanism: Enzymatic degradation by tissue enzymes
• Types:
  • Plain catgut: Resorbs in 7-10 days
  • Chromic catgut: Cross-linked with chromium, resorbs in 2-3 weeks
• Advantages: Natural, good handling
• Disadvantages: Variable absorption, inflammatory response, potential allergic reactions

Vicryl (Polyglactin 910)

• Composition: Synthetic copolymer of glycolic and lactic acid
• Degradation mechanism: Hydrolysis (broken down by water)
• Absorption time: 2-3 weeks (loses tensile strength in 2-3 weeks, completely absorbed in 60-90 days)
• Variants:
  • Vicryl: Standard braided suture
  • Vicryl Rapide: Faster absorption (7-10 days)
  • Vicryl Plus: Contains triclosan for antibacterial properties
• Advantages: Predictable absorption, minimal tissue reaction, good knot security
• Clinical uses: Soft tissue closure, periodontal surgery, buried sutures

Polydiaxone (PDS-II)

• Composition: Synthetic polymer (polydioxanone)
• Structure: Monofilament
• Degradation mechanism: Hydrolysis
• Absorption time: ~6 months with minimal tissue reaction
• Tensile strength: Retains 70% at 2 weeks, 50% at 4 weeks
• Advantages:
  • Longest absorption time among synthetic absorbables
  • Excellent biocompatibility
  • Minimal inflammatory response
  • Good for wounds requiring extended support
• Clinical uses: Deep tissue layers, slow-healing wounds, pediatric surgery

Other Synthetic Absorbable Sutures

Monocryl (Poliglecaprone 25)

• Absorption: 3-4 months
• Advantages: Low tissue reaction, good cosmetic results
• Uses: Subcuticular closure, soft tissue approximation

Biosyn (Glycomer 631)

• Absorption: 3-4 months
• Advantages: Braided with monofilament properties
• Uses: General soft tissue approximation

 Gate Control Theory (Melzack & Wall, 1965)

• Suggests pain modulation occurs in the spinal dorsal horn before reaching the brain.
• Small fibers (A-delta & C) transmit nociceptive (pain) signals.
• Large fibers (A-beta) inhibit pain by activating inhibitory interneurons.
• The “gate” can be closed by:
  • Non-painful stimuli (e.g. touch, vibration)
  • Descending pathways from brain
  • Pharmacologic methods (opioids, local anesthetics)

Clinical Applications

• Explains effect of rubbing injured site
• Basis of TENS therapy and physiotherapy techniques
• Encourages multimodal analgesia
• Supports cognitive-behavioral strategies (distraction, relaxation)

Approaches to the Oral Cavity in Oral Cancer Treatment

In the management of oral cancer, surgical approaches are tailored to the location and extent of the lesions. The choice of surgical technique is crucial for achieving adequate tumor resection while preserving surrounding structures and function. Below are the primary surgical approaches used in the treatment of oral cancer:

1. Peroral Approach

• Indication: This approach is primarily used for small, anteriorly placed lesions within the oral cavity.
• Technique: The surgeon accesses the lesion directly through the mouth without external incisions. This method is less invasive and is suitable for superficial lesions that do not require extensive resection.
• Advantages:
  • Minimal morbidity and scarring.
  • Shorter recovery time.
• Limitations: Not suitable for larger or posterior lesions due to limited visibility and access.

2. Lip Split Approach

• Indication: This approach is utilized for posteriorly based lesions in the gingivobuccal complex and for performing marginal mandibulectomy.
• Technique: A vertical incision is made through the lip, allowing for the elevation of a cheek flap. This provides better access to the posterior aspects of the oral cavity and the mandible.
• Advantages:
  • Improved access to the posterior oral cavity.
  • Facilitates the removal of larger lesions and allows for better visualization of the surgical field.
• Limitations: Potential for cosmetic concerns and longer recovery time compared to peroral approaches.

3. Pull-Through Approach

• Indication: This technique is particularly useful for lesions of the tongue and floor of the mouth, especially when the posterior margin is a concern for peroral excision.
• Technique: The lesion is accessed by pulling the tongue or floor of the mouth forward, allowing for better exposure and resection of the tumor while ensuring adequate margins.
• Advantages:
  • Enhanced visibility and access to the posterior margins of the lesion.
  • Allows for more precise excision of tumors located in challenging areas.
• Limitations: May require additional incisions or manipulation of surrounding tissues, which can increase recovery time.

4. Mandibulotomy (Median or Paramedian)

• Indication: This approach is indicated for tongue and floor of mouth lesions that are close to the mandible, particularly when achieving a lateral margin of clearance is critical.
• Technique: A mandibulotomy involves making an incision through the mandible, either in the midline (median) or slightly off-center (paramedian), to gain access to the oral cavity and the lesion.
• Advantages:
  • Provides excellent access to deep-seated lesions and allows for adequate resection with clear margins.
  • Facilitates reconstruction if needed.
• Limitations: Higher morbidity associated with mandibular manipulation, including potential complications such as nonunion or malocclusion.

Enophthalmos

Enophthalmos is a condition characterized by the inward sinking of the eye into the orbit (the bony socket that holds the eye). It is often a troublesome consequence of fractures involving the zygomatic complex (the cheekbone area).

Causes of Enophthalmos

Enophthalmos can occur due to several factors following an injury:

1. Loss of Orbital Volume:

   • There may be a decrease in the volume of the contents within the orbit, which can happen if soft tissues herniate into the maxillary sinus or through the medial wall of the orbit.

2. Fractures of the Orbital Walls:

   • Fractures in the walls of the orbit can increase the volume of the bony orbit. This can occur with lateral and inferior displacement of the zygoma or disruption of the inferior and lateral orbital walls. A quantitative CT scan can help visualize these changes.

3. Loss of Ligament Support:

   • The ligaments that support the eye may be damaged, contributing to the sinking of the eye.

4. Post-Traumatic Changes:

   • After an injury, fibrosis (the formation of excess fibrous connective tissue), scar contraction, and fat atrophy (loss of fat in the orbit) can occur, leading to enophthalmos.

5. Combination of Factors:

   • Often, enophthalmos results from a combination of the above factors.

Diagnosis

• Acute Cases: In the early stages after an injury, diagnosing enophthalmos can be challenging. This is because swelling (edema) of the surrounding soft tissues can create a false appearance of enophthalmos, making it seem like the eye is more sunken than it actually is.

Periodontal Surgery

• Preferred: Vicryl, PDS-II for buried sutures
• Surface: Silk or nylon for easy removal
• Size: 4-0 to 6-0

Extraction Sites

• Simple extractions: Often no sutures needed
• Surgical extractions: 3-0 or 4-0 silk or Vicryl
• Alveolar bone contouring: Resorbable sutures preferred

Implant Surgery

• Flap closure: Non-absorbable for precise control
• Healing abutment placement: Absorbable around healing caps
• Size: 4-0 to 5-0

Oral Pathology/Biopsy

• Deep tissues: PDS-II for extended support
• Surface: Fine silk or nylon (5-0, 6-0)
• Cosmetic areas: Monocryl for subcuticular closure

Trauma/Laceration Repair

• Layered closure: Absorbable for deep layers, non-absorbable for surface
• Muscle: Vicryl or PDS-II
• Mucosa: Silk or Vicryl
• Skin: Nylon or polypropylene

Unicystic Ameloblastoma

Unicystic ameloblastoma is a specific type of ameloblastoma characterized by a single cystic cavity that exhibits ameloblastomatous differentiation in its lining. This type of ameloblastoma is distinct from other forms due to its unique clinical, radiographic features, and behavior.

Characteristics of Unicystic Ameloblastoma

1. Definition:

   • Unicystic ameloblastoma is defined as a single cystic cavity that shows ameloblastomatous differentiation in the lining.

2. Clinical Features:

   • More than 90% of unicystic ameloblastomas are found in the posterior mandible.
   • They typically surround the crown of an unerupted mandibular third molar and may resemble a dentigerous cyst.

3. Radiographic Features:

   • Appears as a well-defined radiolucent lesion, often associated with the crown of an impacted tooth.

4. Histopathology:

   • There are three types of unicystic ameloblastomas:
     • Luminal: The cystic lining shows ameloblastomatous changes without infiltration into the wall.
     • Intraluminal: The tumor is located within the cystic cavity but does not infiltrate the wall.
     • Mural: The wall of the lesion is infiltrated by typical follicular or plexiform ameloblastoma. This type behaves similarly to conventional ameloblastoma and requires more aggressive treatment.

5. Recurrence Rate:

   • Unicystic ameloblastomas, particularly those without mural extension, have a low recurrence rate following conservative treatment.

Treatment of Ameloblastomas

1. Conventional (Follicular) Ameloblastoma:

   • Surgical Resection: Recommended with 1.0 to 1.5 cm margins and removal of one uninvolved anatomic barrier.
   • Enucleation and Curettage: If used, this method has a high recurrence rate (70-85%).

2. Unicystic Ameloblastoma (Without Mural Extension):

   • Conservative Treatment: Enucleation and curettage are typically successful due to the intraluminal location of the tumor.

3. Unicystic Ameloblastoma (With Mural Extension):

   • Aggressive Treatment: Managed similarly to conventional ameloblastomas due to the infiltrative nature of the mural component.

4. Intraosseous Solid and Multicystic Ameloblastomas:

   • Mandibular Excision: Block resection is performed, either with or without continuity defect, removing up to 1.5 cm of clinically normal bone around the margin.

5. Peripheral Ameloblastoma:

   • Simple Excision: These tumors are less aggressive and can be treated with simple excision, ensuring a rim of soft tissue tumor-free margins (1-1.5 cm).
   • If bone involvement is indicated by biopsy, block resection with continuity defect is preferred.

6. Recurrent Ameloblastoma:

   • Recurrences can occur 5-10 years after initial treatment and are best managed by resection with 1.5 cm margins.
   • Resection should be based on initial radiographs rather than those showing recurrence.