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Oral and Maxillofacial Surgery - NEETMDS- courses
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.

Distoangular Impaction

Distoangular impaction refers to the position of a tooth, typically a third molar (wisdom tooth), that is angled towards the back of the mouth and the distal aspect of the mandible. This type of impaction is often considered one of the most challenging to manage surgically due to its orientation and the anatomical considerations involved in its removal.

Characteristics of Distoangular Impaction

  1. Pathway of Delivery:

    • The distoangular position of the tooth means that it is situated in a way that complicates its removal. The pathway for extraction often requires significant manipulation and access through the ascending ramus of the mandible.
  2. Bone Removal:

    • A substantial amount of distal bone removal is necessary to access the tooth adequately. This may involve the use of surgical instruments to contour the bone and create sufficient space for extraction.
  3. Crown Sectioning:

    • Once adequate bone removal has been achieved, the crown of the tooth is typically sectioned from the roots just above the cervical line. This step is crucial for improving visibility and access to the roots, which can be difficult to see and manipulate in their impacted position.
  4. Removal of the Crown:

    • The entire crown is removed to facilitate better access to the roots. This step is essential for ensuring that the roots can be addressed without obstruction from the crown.
  5. Root Management:

    • Divergent Roots: If the roots of the tooth are divergent (spreading apart), they may need to be further sectioned into two pieces. This allows for easier removal of each root individually, reducing the risk of fracture or complications during extraction.
    • Convergent Roots: If the roots are convergent (closer together), a straight elevator can often be used to remove the roots without the need for additional sectioning. The elevator is inserted between the roots to gently lift and dislodge them from the surrounding bone.

Surgical Technique Overview

  1. Anesthesia: Local anesthesia is administered to ensure patient comfort during the procedure.

  2. Incision and Flap Reflection: An incision is made in the mucosa, and a flap is reflected to expose the underlying bone and the impacted tooth.

  3. Bone Removal: Using a surgical bur or chisel, the distal bone is carefully removed to create access to the tooth.

  4. Crown Sectioning: The crown is sectioned from the roots using a surgical handpiece or bur, allowing for improved visibility.

  5. Root Extraction:

    • For divergent roots, each root is sectioned and removed individually.
    • For convergent roots, a straight elevator is used to extract the roots.
  6. Closure: After the tooth is removed, the surgical site is irrigated, and the flap is repositioned and sutured to promote healing.

Considerations and Complications

  • Complications: Distoangular impactions can lead to complications such as nerve injury (especially to the inferior alveolar nerve), infection, and prolonged recovery time.
  • Postoperative Care: Patients should be advised on postoperative care, including pain management, oral hygiene, and signs of complications such as swelling or infection.

Submasseteric Space Infection

Submasseteric space infection refers to an infection that occurs in the submasseteric space, which is located beneath the masseter muscle. This space is clinically significant in the context of dental infections, particularly those arising from the lower third molars (wisdom teeth) or other odontogenic sources. Understanding the anatomy and potential spread of infections in this area is crucial for effective diagnosis and management.

Anatomy of the Submasseteric Space

  1. Location:

    • The submasseteric space is situated beneath the masseter muscle, which is a major muscle involved in mastication (chewing).
    • This space is bordered superiorly by the masseter muscle and inferiorly by the lower border of the ramus of the mandible.
  2. Boundaries:

    • Inferior Boundary: The extension of an abscess or infection inferiorly is limited by the firm attachment of the masseter muscle to the lower border of the ramus of the mandible. This attachment creates a barrier that can restrict the spread of infection downward.
    • Anterior Boundary: The forward spread of infection beyond the anterior border of the ramus is restricted by the anterior tail of the tendon of the temporalis muscle, which inserts into the anterior border of the ramus. This anatomical feature helps to contain infections within the submasseteric space.
  3. Posterior Boundary: The posterior limit of the submasseteric space is generally defined by the posterior border of the ramus of the mandible.

Clinical Implications

  1. Sources of Infection:

    • Infections in the submasseteric space often arise from odontogenic sources, such as:
      • Pericoronitis associated with impacted lower third molars.
      • Dental abscesses from other teeth in the mandible.
      • Periodontal infections.
  2. Symptoms:

    • Patients with submasseteric space infections may present with:
      • Swelling and tenderness in the area of the masseter muscle.
      • Limited mouth opening (trismus) due to muscle spasm or swelling.
      • Pain that may radiate to the ear or temporomandibular joint (TMJ).
      • Fever and systemic signs of infection in more severe cases.
  3. Diagnosis:

    • Diagnosis is typically made through clinical examination and imaging studies, such as panoramic radiographs or CT scans, to assess the extent of the infection and its relationship to surrounding structures.
  4. Management:

    • Treatment of submasseteric space infections usually involves:
      • Antibiotic Therapy: Broad-spectrum antibiotics are often initiated to control the infection.
      • Surgical Intervention: Drainage of the abscess may be necessary, especially if there is significant swelling or if the patient is not responding to conservative management. Incision and drainage can be performed intraorally or extraorally, depending on the extent of the infection.
      • Management of the Source: Addressing the underlying dental issue, such as extraction of an impacted tooth or treatment of a dental abscess, is essential to prevent recurrence.

Basic Principles of Treatment of a Fracture

The treatment of fractures involves a systematic approach to restore the normal anatomy and function of the affected bone. The basic principles of fracture treatment can be summarized in three key steps: reduction, fixation, and immobilization.

1. Reduction

Definition: Reduction is the process of restoring the fractured bone fragments to their original anatomical position.

  • Methods of Reduction:

    • Closed Reduction: This technique involves realigning the bone fragments without direct visualization of the fracture line. It can be achieved through:
      • Reduction by Manipulation: The physician uses manual techniques to manipulate the bone fragments into alignment.
      • Reduction by Traction: Gentle pulling forces are applied to align the fragments, often used in conjunction with other methods.
  • Open Reduction: In some cases, if closed reduction is not successful or if the fracture is complex, an open reduction may be necessary. This involves surgical exposure of the fracture site to directly visualize and align the fragments.

2. Fixation

Definition: After reduction, fixation is the process of stabilizing the fractured fragments in their normal anatomical relationship to prevent displacement and ensure proper healing.

  • Types of Fixation:

    • Internal Fixation: This involves the use of devices such as plates, screws, or intramedullary nails that are placed inside the body to stabilize the fracture.
    • External Fixation: This method uses external devices, such as pins or frames, that are attached to the bone through the skin. External fixation is often used in cases of open fractures or when internal fixation is not feasible.
  • Goals of Fixation: The primary goals are to maintain the alignment of the bone fragments, prevent movement at the fracture site, and facilitate healing.

3. Immobilization

Definition: Immobilization is the phase during which the fixation device is retained to stabilize the reduced fragments until clinical bony union occurs.

  • Duration of Immobilization: The length of the immobilization period varies depending on the type of fracture and the bone involved:

    • Maxillary Fractures: Typically require 3 to 4 weeks of immobilization.
    • Mandibular Fractures: Generally require 4 to 6 weeks of immobilization.
    • Condylar Fractures: Recommended immobilization period is 2 to 3 weeks to prevent temporomandibular joint (TMJ) ankylosis.
  •  

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.

Management of Nasal Complex Fractures

Nasal complex fractures involve injuries to the nasal bones and surrounding structures, including the nasal septum, maxilla, and sometimes the orbits. Proper management is crucial to restore function and aesthetics.

Anesthesia Considerations

  • Local Anesthesia:
    • Nasal complex fractures can be reduced under local anesthesia, which may be sufficient for less complicated cases or when the patient is cooperative.
  • General Anesthesia:
    • For more complex fractures or when significant manipulation of the nasal structures is required, general anesthesia is preferred.
    • Per-oral Endotracheal Tube: This method allows for better airway management and control during the procedure.
    • Throat Pack: A throat pack is often used to minimize the risk of aspiration and to manage any potential hemorrhage, which can be profuse in these cases.

Surgical Technique

  1. Reduction of Fractures:

    • The primary goal is to realign the fractured nasal bones and restore the normal anatomy of the nasal complex.
    • Manipulation of Fragments:
      • Walsham’s Forceps: These are specialized instruments used to grasp and manipulate the nasal bone fragments during reduction.
      • Asche’s Forceps: Another type of forceps that can be used for similar purposes, allowing for precise control over the fractured segments.
  2. Post-Reduction Care:

    • After the reduction, the nasal structures may be stabilized using splints or packing to maintain alignment during the healing process.
    • Monitoring for complications such as bleeding, infection, or airway obstruction is essential.

Gow-Gates Technique for Mandibular Anesthesia

The Gow-Gates technique is a well-established method for achieving effective anesthesia of the mandibular teeth and associated soft tissues. Developed by George Albert Edwards Gow-Gates, this technique is known for its high success rate in providing sensory anesthesia to the entire distribution of the mandibular nerve (V3).

Overview

  • Challenges in Mandibular Anesthesia: Achieving successful anesthesia in the mandible is often more difficult than in the maxilla due to:
    • Greater anatomical variation in the mandible.
    • The need for deeper penetration of soft tissues.
  • Success Rate: Gow-Gates reported an astonishing success rate of approximately 99% in his experienced hands, making it a reliable choice for dental practitioners.

Anesthesia Coverage

The Gow-Gates technique provides sensory anesthesia to the following nerves:

  • Inferior Alveolar Nerve
  • Lingual Nerve
  • Mylohyoid Nerve
  • Mental Nerve
  • Incisive Nerve
  • Auriculotemporal Nerve
  • Buccal Nerve

This comprehensive coverage makes it particularly useful for procedures involving multiple mandibular teeth.

Technique

Equipment

  • Needle: A 25- or 27-gauge long needle is recommended for this technique.

Injection Site and Target Area

  1. Area of Insertion:

    • The injection is performed on the mucous membrane on the mesial aspect of the mandibular ramus.
    • The insertion point is located on a line drawn from the intertragic notch to the corner of the mouth, just distal to the maxillary second molar.
  2. Target Area:

    • The target for the injection is the lateral side of the condylar neck, just below the insertion of the lateral pterygoid muscle.

Landmarks

Extraoral Landmarks:

  • Lower Border of the Tragus: This serves as a reference point. The center of the external auditory meatus is the ideal landmark, but since it is concealed by the tragus, the lower border is used as a visual aid.
  • Corner of the Mouth: This helps in aligning the injection site.

Intraoral Landmarks:

  • Height of Injection: The needle tip should be placed just below the mesiopalatal cusp of the maxillary second molar to establish the correct height for the injection.
  • Penetration Point: The needle should penetrate the soft tissues just distal to the maxillary second molar at the height established in the previous step.

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