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📖 Oral and Maxillofacial Surgery

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Augmentation of the Inferior Border of the Mandible
Oral and Maxillofacial Surgery

Augmentation of the Inferior Border of the Mandible

Mandibular augmentation refers to surgical procedures aimed at increasing the height or contour of the mandible, particularly the inferior border. This type of augmentation is often performed to improve the support for dentures, enhance facial aesthetics, or correct deformities. Below is an overview of the advantages and disadvantages of augmenting the inferior border of the mandible.

Advantages of Inferior Border Augmentation

  1. Preservation of the Vestibule:

    • The procedure does not obliterate the vestibule, allowing for the immediate placement of an interim denture. This is particularly beneficial for patients who require prosthetic support soon after surgery.

  2. No Change in Vertical Dimension:

    • Augmentation of the inferior border does not alter the vertical dimension of the occlusion, which is crucial for maintaining proper bite relationships and avoiding complications associated with changes in jaw alignment.

  3. Facilitation of Secondary Vestibuloplasty:

    • The procedure makes subsequent vestibuloplasty easier. By maintaining the vestibular space, it allows for better access and manipulation during any future surgical interventions aimed at deepening the vestibule.

  4. Protection of the Graft:

    • The graft used for augmentation is not subjected to direct masticatory forces, reducing the risk of graft failure and promoting better healing. This is particularly important in ensuring the longevity and stability of the augmentation.

Disadvantages of Inferior Border Augmentation

  1. Extraoral Scar:

    • The procedure typically involves an incision that can result in an extraoral scar. This may be a cosmetic concern for some patients, especially if the scar is prominent or does not heal well.

  2. Potential Alteration of Facial Appearance:

    • If the submental and submandibular tissues are not initially loose, there is a risk of altering the facial appearance. Tight or inelastic tissues may lead to distortion or asymmetry postoperatively.

  3. Limited Change in Superior Surface Shape:

    • The augmentation primarily affects the inferior border of the mandible and may not significantly change the shape of the superior surface of the mandible. This limitation can affect the overall contour and aesthetics of the jawline.

  4. Surgical Risks:

    • As with any surgical procedure, there are inherent risks, including infection, bleeding, and complications related to anesthesia. Additionally, there may be risks associated with the grafting material used.
Surgical Approaches in Oral and Maxillofacial Surgery
Oral and Maxillofacial Surgery

Surgical Approaches in Oral and Maxillofacial Surgery

In the management of tumors and lesions in the oral and maxillofacial region, various surgical approaches are employed based on the extent of the disease, the involvement of surrounding structures, and the need for reconstruction. Below is a detailed overview of the surgical techniques mentioned, along with their indications and reconstruction options.

1. Marginal / Segmental / En Bloc Resection

Definition:

  • En Bloc Resection: This technique involves the complete removal of a tumor along with a margin of healthy tissue, without disrupting the continuity of the bone. It is often used for tumors that are well-defined and localized.

Indications:

  • No Cortical Perforation: En bloc segmental resection is indicated when there is no evidence of cortical bone perforation. This allows for the removal of the tumor while preserving the structural integrity of the surrounding bone.
  • Tumor Characteristics: This approach is suitable for benign tumors or low-grade malignancies that have not invaded surrounding tissues.

2. Partial Resection (Mandibulectomy)

Definition:

  • Mandibulectomy: This procedure involves the resection of a portion of the mandible, typically performed when a tumor is present.

Indications:

  • Cortical Perforation: Mandibulectomy is indicated when there is cortical perforation of the mandible. This means that the tumor has invaded the cortical bone, necessitating a more extensive surgical approach.
  • Clearance Margin: A margin of at least 1 cm of healthy bone is typically removed to ensure complete excision of the tumor and reduce the risk of recurrence.

3. Total Resection (Hemimandibulectomy)

Definition:

  • Hemimandibulectomy: This procedure involves the resection of one half of the mandible, including the associated soft tissues.

Indications:

  • Perforation of Bone and Soft Tissue: Hemimandibulectomy is indicated when there is both perforation of the bone and involvement of the surrounding soft tissues. This is often seen in more aggressive tumors or those that have metastasized.
  • Extensive Tumor Involvement: This approach is necessary for tumors that cannot be adequately removed with less invasive techniques due to their size or location.

4. Reconstruction

Following resection, reconstruction of the jaw is often necessary to restore function and aesthetics. Several options are available for reconstruction:

a. Reconstruction Plate:

  • Description: A reconstruction plate is a rigid plate made of titanium or other biocompatible materials that is used to stabilize the bone after resection.
  • Indications: Used in cases where structural support is needed to maintain the shape and function of the mandible.

b. K-wire:

  • Description: K-wires are thin, flexible wires used to stabilize bone fragments during the healing process.
  • Indications: Often used in conjunction with other reconstruction methods to provide additional support.

c. Titanium Mesh:

  • Description: Titanium mesh is a flexible mesh that can be shaped to fit the contours of the jaw and provide support for soft tissue and bone.
  • Indications: Used in cases where there is significant bone loss and soft tissue coverage is required.

d. Rib Graft / Iliac Crest Graft:

  • Description: Autogenous bone grafts can be harvested from the rib or iliac crest to reconstruct the mandible.
  • Indications: These grafts are used when significant bone volume is needed for reconstruction, providing a biological scaffold for new bone formation.
Osteomyelitis
Oral and Maxillofacial Surgery

Osteomyelitis is an infection of the bone that can occur in the jaw, particularly in the mandible, and is characterized by a range of clinical features. Understanding these features is essential for effective diagnosis and management, especially in the context of preparing for the Integrated National Board Dental Examination (INBDE). Here’s a detailed overview of the clinical features, occurrence, and implications of osteomyelitis, particularly in adults and children.

Occurrence

  • Location: In adults, osteomyelitis is more common in the mandible than in the maxilla. The areas most frequently affected include:
    • Alveolar process
    • Angle of the mandible
    • Posterior part of the ramus
    • Coronoid process
  • Rarity: Osteomyelitis of the condyle is reportedly rare (Linsey, 1953).

Clinical Features

Early Symptoms

  1. Generalized Constitutional Symptoms:

    • Fever: High intermittent fever is common.
    • Malaise: Patients often feel generally unwell.
    • Gastrointestinal Symptoms: Nausea, vomiting, and anorexia may occur.

  2. Pain:

    • Nature: Patients experience deep-seated, boring, continuous, and intense pain in the affected area.
    • Location: The pain is typically localized to the mandible.

  3. Neurological Symptoms:

    • Paresthesia or Anesthesia: Intermittent paresthesia or anesthesia of the lower lip can occur, which helps differentiate osteomyelitis from an alveolar abscess.

  4. Facial Swelling:

    • Cellulitis: Patients may present with facial cellulitis or indurated swelling, which is more confined to the periosteal envelope and its contents.
    • Mechanisms:
      • Thrombosis of the inferior alveolar vasa nervorum.
      • Increased pressure from edema in the inferior alveolar canal.
    • Dental Symptoms: Affected teeth may be tender to percussion and may appear loose.

  5. Trismus:

    • Limited mouth opening due to muscle spasm or inflammation in the area.

Pediatric Considerations

  • In children, osteomyelitis can present more severely and may be characterized by:
    • Fulminating Course: Rapid onset and progression of symptoms.
    • Severe Involvement: Both maxilla and mandible can be affected.
    • Complications: The presence of unerupted developing teeth buds can complicate the condition, as they may become necrotic and act as foreign bodies, prolonging the disease process.
    • TMJ Involvement: Long-term involvement of the temporomandibular joint (TMJ) can lead to ankylosis, affecting the growth and development of facial structures.

Radiographic Changes

  • Timing of Changes: Radiographic changes typically occur only after the initiation of the osteomyelitis process.
  • Bone Loss: Significant radiographic changes are noted only after 30% to 60% of mineralized bone has been destroyed.
  • Delay in Detection: This degree of bone alteration requires a minimum of 4 to 8 days after the onset of acute osteomyelitis for changes to be visible on radiographs.
Extraction Patterns for Presurgical Orthodontics
Oral and Maxillofacial Surgery

Extraction Patterns for Presurgical Orthodontics

In orthodontics, the extraction pattern chosen can significantly influence treatment outcomes, especially in presurgical orthodontics. The extraction decisions differ based on the type of skeletal malocclusion, specifically Class II and Class III malocclusions. Here’s an overview of the extraction patterns for each type:

Skeletal Class II Malocclusion

  • General Approach:
    • In skeletal Class II malocclusion, the goal is to prepare the dental arches for surgical correction, typically involving mandibular advancement.
  • Extraction Recommendations:
    • No Maxillary Tooth Extraction: Avoid extracting maxillary teeth, particularly the upper first premolars or any maxillary teeth, to prevent over-retraction of the maxillary anterior teeth. Over-retraction can compromise the planned mandibular advancement.
    • Lower First Premolar Extraction: Extraction of the lower first premolars is recommended. This helps:
      • Level the arch.
      • Correct the proclination of the lower anterior teeth, allowing for better alignment and preparation for surgery.

Skeletal Class III Malocclusion

  • General Approach:

    • In skeletal Class III malocclusion, the extraction pattern is reversed to facilitate the surgical correction, often involving maxillary advancement or mandibular setback.

  • Extraction Recommendations:

    • Upper First Premolar Extraction: Extracting the upper first premolars is done to:
      • Correct the proclination of the upper anterior teeth, which is essential for achieving proper alignment and aesthetics.
    • Lower Second Premolar Extraction: If additional space is needed in the lower arch, the extraction of lower second premolars is recommended. This helps:
      • Prevent over-retraction of the lower anterior teeth, maintaining their position while allowing for necessary adjustments in the arch.