Tongue Thrust

Tongue thrust is characterized by the forward movement of the tongue tip between the teeth to meet the lower lip during swallowing and speech, resulting in an interdental position of the tongue (Tulley, 1969). This habit can lead to various dental and orthodontic issues, particularly malocclusions such as anterior open bite.

Etiology of Tongue Thrust

1. Retained Infantile Swallow:

   • The tongue does not drop back as it should after the eruption of incisors, continuing to thrust forward during swallowing.

2. Upper Respiratory Tract Infection:

   • Conditions such as mouth breathing and allergies can contribute to tongue thrusting behavior.

3. Neurological Disturbances:

   • Issues such as hyposensitivity of the palate or disruption of sensory control and coordination during swallowing can lead to tongue thrust.

4. Feeding Practices:

   • Bottle feeding is more likely to contribute to the development of tongue thrust compared to breastfeeding.

5. Induced by Other Oral Habits:

   • Habits like thumb sucking or finger sucking can create malocclusions (e.g., anterior open bite), leading to the tongue protruding between the anterior teeth during swallowing.

6. Hereditary Factors:

   • A family history of tongue thrusting or related oral habits may contribute to the development of the condition.

7. Tongue Size:

   • Conditions such as macroglossia (enlarged tongue) can predispose individuals to tongue thrusting.

Clinical Features

Extraoral

• Lip Posture: Increased lip separation both at rest and during function.
• Mandibular Movement: The path of mandibular movement is upward and backward, with the tongue moving forward.
• Speech: Articulation problems, particularly with sounds such as /s/, /n/, /t/, /d/, /l/, /th/, /z/, and /v/.
• Facial Form: Increased anterior facial height may be observed.

Intraoral

1. Tongue Posture: The tongue tip is lower at rest due to the presence of an anterior open bite.
2. Malocclusion:
   • Maxilla:
     • Proclination of maxillary anterior teeth.
     • Increased overjet.
     • Maxillary constriction.
     • Generalized spacing between teeth.
   • Mandible:
     • Retroclination of mandibular teeth.

Diagnosis

History

• Family History: Determine the swallow patterns of siblings and parents to check for hereditary factors.
• Medical History: Gather information regarding upper respiratory infections and sucking habits.
• Patient Motivation: Assess the patient’s overall abilities, interests, and motivation for treatment.

Examination

1. Swallowing Assessment:

   • Normal Swallowing:
     • Lips touch tightly.
     • Mandible rises as teeth come together.
     • Facial muscles show no marked contraction.
   • Abnormal Swallowing:
     • Teeth remain apart.
     • Lips do not touch.
     • Facial muscles show marked contraction.

2. Inhibition Test:

   • Lightly hold the lower lip with a thumb and finger while the patient is asked to swallow water.
   • Normal Swallowing: The patient can swallow normally.
   • Abnormal Swallowing: The swallow is inhibited, requiring strong mentalis and lip contraction for mandibular stabilization, leading to water spilling from the mouth.

Management

1. Behavioral Therapy:

   • Awareness Training: Educate the patient about the habit and its effects on oral health.
   • Positive Reinforcement: Encourage the patient to practice proper swallowing techniques and reward progress.

2. Myofunctional Therapy:

   • Involves exercises to improve tongue posture and function, helping to retrain the muscles involved in swallowing and speech.

3. Orthodontic Treatment:

   • If malocclusion is present, orthodontic intervention may be necessary to correct the dental alignment and occlusion.
   • Appliances such as a palatal crib or tongue thrusting appliances can be used to discourage the habit.

4. Speech Therapy:

   • If speech issues are present, working with a speech therapist can help address articulation problems and improve speech clarity.

5. Monitoring and Follow-Up:

   • Regular follow-up appointments to monitor progress and make necessary adjustments to the treatment plan.

Relapse

Definition: Relapse refers to the tendency of teeth to return to their original positions after orthodontic treatment. This can occur due to various factors, including the natural elasticity of the periodontal ligament, muscle forces, and the influence of oral habits.

Causes of Relapse

1. Elasticity of the Periodontal Ligament: After orthodontic treatment, the periodontal ligament may still have a tendency to revert to its original state, leading to tooth movement.
2. Muscle Forces: The forces exerted by the lips, cheeks, and tongue can influence tooth positions, especially if these forces are not balanced.
3. Growth and Development: In growing patients, changes in jaw size and shape can lead to shifts in tooth positions.
4. Non-Compliance with Retainers: Failure to wear retainers as prescribed can significantly increase the risk of relapse.

Prevention of Relapse

• Consistent Retainer Use: Adhering to the retainer regimen as prescribed by the orthodontist is crucial for maintaining tooth positions.
• Regular Follow-Up Visits: Periodic check-ups with the orthodontist can help monitor tooth positions and address any concerns early.
• Patient Education: Educating patients about the importance of retention and the potential for relapse can improve compliance with retainer wear.

The Nance Appliance is a fixed orthodontic device used primarily in the upper arch to maintain space and prevent the molars from drifting forward. It is particularly useful in cases where there is a need to hold the position of the maxillary molars after the premature loss of primary molars or to maintain space for the eruption of permanent teeth. Below is an overview of the Nance Appliance, its components, functions, indications, advantages, and limitations.

Components of the Nance Appliance

1. Baseplate:

   • The Nance Appliance features an acrylic baseplate that is custom-made to fit the palate. This baseplate is typically made of a pink acrylic material that is molded to the shape of the patient's palate.

2. Anterior Button:

   • A prominent feature of the Nance Appliance is the anterior button, which is positioned against the anterior teeth (usually the incisors). This button helps to stabilize the appliance and provides a point of contact to prevent the molars from moving forward.

3. Bands:

   • The appliance is anchored to the maxillary molars using bands that are cemented onto the molars. These bands provide the necessary anchorage for the appliance.

4. Wire Framework:

   • A wire framework may be incorporated into the appliance to enhance its strength and stability. This framework typically consists of a stainless steel wire that connects the bands and the anterior button.

Functions of the Nance Appliance

1. Space Maintenance:

   • The primary function of the Nance Appliance is to maintain space in the upper arch, particularly after the loss of primary molars. It prevents the adjacent teeth from drifting into the space, ensuring that there is adequate room for the eruption of permanent teeth.

2. Molar Stabilization:

   • The appliance helps stabilize the maxillary molars in their proper position, preventing them from moving forward or mesially during orthodontic treatment.

3. Arch Development:

   • In some cases, the Nance Appliance can assist in arch development by providing a stable base for other orthodontic appliances or treatments.

Indications for Use

• Premature Loss of Primary Molars: To maintain space for the eruption of permanent molars when primary molars are lost early.
• Crowding: To prevent adjacent teeth from drifting into the space created by lost teeth, which can lead to crowding.
• Molar Stabilization: To stabilize the position of the maxillary molars during orthodontic treatment.

Advantages of the Nance Appliance

1. Fixed Appliance: As a fixed appliance, the Nance Appliance does not rely on patient compliance, ensuring consistent space maintenance.
2. Effective Space Maintenance: It effectively prevents unwanted tooth movement and maintains space for the eruption of permanent teeth.
3. Minimal Discomfort: Generally, patients tolerate the Nance Appliance well, and it does not cause significant discomfort.

Limitations of the Nance Appliance

1. Oral Hygiene: Maintaining oral hygiene can be more challenging with fixed appliances, and patients must be diligent in their oral care to prevent plaque accumulation and dental issues.
2. Limited Movement: The Nance Appliance primarily affects the molars and may not be effective for moving anterior teeth.
3. Adjustment Needs: While the appliance is generally stable, it may require periodic adjustments or monitoring by the orthodontist.

Catalan's Appliance

Catalan's appliance, also known as the Catalan appliance or lower inclined bite plane, is an orthodontic device primarily used to correct anterior crossbites and manage dental arch relationships. It is particularly effective in growing children and adolescents, as it helps to guide the development of the dental arches and improve occlusion.

Indications for Use

1. Anterior Crossbite:

   • The primary indication for Catalan's appliance is to correct anterior crossbites, where the upper front teeth are positioned behind the lower front teeth when the jaws are closed.

2. Space Management:

   • It can be used to create space in the dental arch, especially when there is crowding or insufficient space for the eruption of permanent teeth.

3. Guiding Eruption:

   • The appliance helps guide the eruption of the permanent teeth into a more favorable position, promoting proper alignment.

4. Facilitating Growth:

   • It can assist in the growth of the maxilla and mandible, helping to achieve a more balanced facial profile.

Design and Features

• Components:

  • The Catalan's appliance typically consists of:
    • Acrylic Base: A custom-fitted acrylic base that covers the lower anterior teeth.
    • Inclined Plane: An inclined plane is incorporated into the appliance, which helps to reposition the anterior teeth by providing a surface for the teeth to occlude against.
    • Retention Mechanism: The appliance is retained in the mouth using clasps or other anchorage methods to ensure stability during treatment.

• Customization:

  • The appliance is custom-made for each patient based on their specific dental anatomy and treatment needs. This ensures a proper fit and effective function.

Mechanism of Action

• Correction of Crossbite:

  • The inclined plane of the Catalan's appliance exerts forces on the anterior teeth, encouraging them to move into a more favorable position. This helps to correct the crossbite by allowing the maxillary incisors to move forward relative to the mandibular incisors.

• Space Creation:

  • By repositioning the anterior teeth, the appliance can create additional space in the dental arch, facilitating the eruption of permanent teeth and improving overall alignment.

• Guiding Eruption:

  • The appliance helps guide the eruption of the permanent teeth by maintaining proper arch form and preventing unwanted movements of the teeth.

Retention

Definition: Retention refers to the phase following active orthodontic treatment where appliances are used to maintain the corrected positions of the teeth. The goal of retention is to prevent relapse and ensure that the teeth remain in their new, desired positions.

Types of Retainers

1. Fixed Retainers:

   • Description: These are bonded to the lingual surfaces of the teeth, typically the anterior teeth, to maintain their positions.
   • Advantages: They provide continuous retention without requiring patient compliance.
   • Disadvantages: They can make oral hygiene more challenging and may require periodic replacement.

2. Removable Retainers:

   • Description: These are appliances that can be taken out by the patient. Common types include:
     • Hawley Retainer: A custom-made acrylic plate with a wire framework that holds the teeth in position.
     • Essix Retainer: A clear, plastic retainer that fits over the teeth, providing a more aesthetic option.
   • Advantages: Easier to clean and can be removed for eating and oral hygiene.
   • Disadvantages: Their effectiveness relies on patient compliance; if not worn as prescribed, relapse may occur.

Duration of Retention

• The duration of retention varies based on individual cases, but it is generally recommended to wear retainers full-time for a period (often several months to a year) and then transition to nighttime wear for an extended period (often several years).
• Long-term retention may be necessary for some patients, especially those with a history of dental movement or specific malocclusions.

Angle's Classification of Malocclusion

Developed by Dr. Edward Angle in the early 20th century, this classification is based on the relationship of the first molars and the canines. It is divided into three main classes:

Class I Malocclusion (Normal Occlusion)

• Description: The first molars are in a normal relationship, with the mesiobuccal cusp of the maxillary first molar fitting into the buccal groove of the mandibular first molar. The canines also have a normal relationship.
• Characteristics:
  • The dental arches are aligned.
  • There may be crowding, spacing, or other dental irregularities, but the overall molar relationship is normal.

Class II Malocclusion (Distocclusion)

• Description: The first molars are positioned such that the mesiobuccal cusp of the maxillary first molar is positioned more than one cusp width ahead of the buccal groove of the mandibular first molar.
• Subdivisions:
  • Class II Division 1: Characterized by protruded maxillary incisors and a deep overbite.
  • Class II Division 2: Characterized by retroclined maxillary incisors and a deep overbite, often with a normal or reduced overjet.
• Characteristics: This class often results in an overbite and can lead to aesthetic concerns.

Class III Malocclusion (Mesioocclusion)

• Description: The first molars are positioned such that the mesiobuccal cusp of the maxillary first molar is positioned more than one cusp width behind the buccal groove of the mandibular first molar.
• Characteristics:
  • This class is often associated with an underbite, where the lower teeth are positioned more forward than the upper teeth.
  • It can lead to functional issues and aesthetic concerns.

2. Skeletal Classification

In addition to Angle's classification, malocclusion can also be classified based on skeletal relationships, which consider the position of the maxilla and mandible in relation to each other. This classification is particularly useful in assessing the underlying skeletal discrepancies that may contribute to malocclusion.

Class I Skeletal Relationship

• Description: The maxilla and mandible are in a normal relationship, similar to Class I malocclusion in Angle's classification.
• Characteristics: The skeletal bases are well-aligned, but there may still be dental irregularities.

Class II Skeletal Relationship

• Description: The mandible is positioned further back relative to the maxilla, similar to Class II malocclusion.
• Characteristics: This can be due to a retruded mandible or an overdeveloped maxilla.

Class III Skeletal Relationship

• Description: The mandible is positioned further forward relative to the maxilla, similar to Class III malocclusion.
• Characteristics: This can be due to a protruded mandible or a retruded maxilla.

3. Other Classifications

In addition to Angle's and skeletal classifications, malocclusion can also be described based on specific characteristics:

• Overbite: The vertical overlap of the upper incisors over the lower incisors. It can be classified as:

  • Normal Overbite: Approximately 1-2 mm of overlap.
  • Deep Overbite: Excessive overlap, which can lead to impaction of the lower incisors.
  • Open Bite: Lack of vertical overlap, where the upper and lower incisors do not touch.

• Overjet: The horizontal distance between the labioincisal edge of the upper incisors and the linguoincisal edge of the lower incisors. It can be classified as:

  • Normal Overjet: Approximately 2-4 mm.
  • Increased Overjet: Greater than 4 mm, often associated with Class II malocclusion.
  • Decreased Overjet: Less than 2 mm, often associated with Class III malocclusion.

• Crossbite: A condition where one or more of the upper teeth bite on the inside of the lower teeth. It can be:

  • Anterior Crossbite: Involves the front teeth.
  • Posterior Crossbite: Involves the back teeth.