Frankel appliance is a functional orthodontic device designed to guide facial growth and correct malocclusions. There are four main types: Frankel I (for Class I and Class II Division 1 malocclusions), Frankel II (for Class II Division 2), Frankel III (for Class III malocclusions), and Frankel IV (for specific cases requiring unique adjustments). Each type addresses different dental and skeletal relationships.

The Frankel appliance is a removable orthodontic device that plays a crucial role in the treatment of various malocclusions. It is designed to influence the growth of the jaw and dental arches by modifying muscle function and promoting proper alignment of teeth.

Types of Frankel Appliances

1. Frankel I:

   • Indications: Primarily used for Class I and Class II Division 1 malocclusions.
   • Function: Helps in correcting overjet and improving dental alignment.

2. Frankel II:

   • Indications: Specifically designed for Class II Division 2 malocclusions.
   • Function: Aims to reposition the maxilla and improve the relationship between the upper and lower teeth.

3. Frankel III:

   • Indications: Used for Class III malocclusions.
   • Function: Encourages forward positioning of the maxilla and helps in correcting the skeletal relationship.

4. Frankel IV:

   • Indications: Suitable for open bites and bimaxillary protrusions.
   • Function: Focuses on creating space and improving the occlusion by addressing specific dental and skeletal issues.

Key Features of Frankel Appliances

• Myofunctional Design: The appliance is designed to utilize the forces generated by muscle function to guide the growth of the dental arches.

• Removable: Patients can take the appliance out for cleaning and during meals, which enhances comfort and hygiene.

• Custom Fit: Each appliance is tailored to the individual patient's dental anatomy, ensuring effective treatment.

Treatment Goals

• Facial Balance: The primary goal of using a Frankel appliance is to achieve facial harmony and balance by correcting malocclusions.

• Functional Improvement: It promotes the establishment of normal muscle function, which is essential for long-term dental health.

• Arch Development: The appliance aids in the development of the dental arches, providing adequate space for the eruption of permanent teeth.

SEQUENCE OF ERUPTION OF DECIDUOUS TEETH

Upper/Lower   A B D C E 

SEQUENCE OF ERUPTION OF PERMAMENT TEETH 

Upper:   6 1 2 4 3 5 7           Lower:    6 1 2 3 4 5 7   
      
or       6 1 2 4 5 3 7              or  6 1 2 4 3 5 7 
 

ANTHROPOID SPACE / PRIMATE SPACE / SIMIEN’S SPACE  

The space mesial to upper deciduous canine and distal to lower deciduous  canine is characteristically found in primates and hence it is called primate space.  

INCISOR LIABILITY 

When the permanent central incisor erupt, these teeth use up specially all the spaces found in the normal dentition. With the eruption of permanent lateral incisor the space situation becomes tight. In the maxillary arch it is just enough to accommodate but in mandibular arch there is an average 1.6 mm less space available. This difference between the space present and space required is known as incisor liability. 
These conditions overcome by;  

      1. This is a transient condition and extra space comes from slight increase in arch width.   
      2. Slight labial positioning of central and lateral incisor. 
      3. Distal shift of permanent canine.        

      
LEE WAY SPACE (OF NANCE)  

The combined mesiodistal width of the permanent canines and pre molars is usually less that of the deciduous canines and molars. This space is 
called leeway space of Nance.     

Measurement of lee way space: 
 
Is greater in the mandibular arch than in the maxillary arch  It is about 1.8mm [0.9mm on each side of the arch] in the maxillary arch. 
And about 3.4mm [1.7 mm on side of the arch] in the mandibular arch. 
 
Importance:  

 This lee way space allows the mesial movement of lower molar there by correcting flush terminal plane.     
 LWS can be measure with the help of cephalometry.    

FLUSH TERMINAL PLANE (TERMINAL PLANE RELATIONSHIP) 

Mandibular 2nd deciduous molar is usually wider mesio-distally then the maxillary 2nd deciduous molar. This leads to the development of flush terminal plane which falls along the distal surface of upper and lower 2nd deciduous molar. This develops into class I molar relationship. 

Distal step relationship leads to class 2 relationship.
Mesial step relationship mostly leads to class 3 relationship.  

FEATURE OF IDEAL OCCLUSION IN PRIMARY DENTITION 

1. Spacing of anterior teeth. 
2. Primate space is present. 
3. Flush terminal plane is found. 
4. Almost vertical inclination of anterior teeth. 
5. Overbite and overjet varies.  

UGLY DUCKLING STAGE  

Definition:  
Stage of a transient or self correcting malocclusion is seen sometimes is called ugly duck ling stage. 
 
Occurring site: Maxillary incisor region 

Occuring age: 8-9 years of age.  

This situation is seen during the eruption of the permanent canines. As the developing p.c. they displace the roots of lateral incisor mesially this results is transmitting of the force on to the roots of the central incisors which also gets displaced mesially. A resultant distal divergence of the crowns of the two central incisors causes midline spacing.  

This portion of teeth at this stage is compared to that of ugly walk of the duckling and hence it is called Ugly Duckling Stage. 

Described by Broad bent. In this stage children tend to look ugly. Parents are often apprehensive during this stage and consult the dentist.  

Corrects by itself, when canines erupt and the pressure is transferred from the roots to the coronal area of the incisor.  
IMPORTANCE OF 1ST MOLAR
 
1. It is the key tooth to occlusion. 
2.  Angle’s classification is based on this tooth. 
3.  It is the tooth of choice for anchorage. 
4.  Supports occlusion in a vertical direction. 
5.  Loss of this tooth leads to migration of other tooth. 
6.  Helps in opening the bite.   

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.

Types of Forces in Tooth Movement

1. Light Forces:

   •  Forces that are gentle and continuous, typically in the range of 50-100 grams.
   • Effect: Light forces are ideal for orthodontic tooth movement as they promote biological responses without causing damage to the periodontal ligament or surrounding bone.
   • Examples: Springs, elastics, and aligners.

2. Heavy Forces:

   •  Forces that exceed the threshold of light forces, often greater than 200 grams.
   • Effect: Heavy forces can lead to rapid tooth movement but may cause damage to the periodontal tissues, including root resorption and loss of anchorage.
   • Examples: Certain types of fixed appliances or excessive activation of springs.

3. Continuous Forces:

   •  Forces that are applied consistently over time.
   • Effect: Continuous forces are essential for effective tooth movement, as they maintain the pressure-tension balance in the periodontal ligament.
   • Examples: Archwires in fixed appliances or continuous elastic bands.

4. Intermittent Forces:

   •  Forces that are applied in a pulsed or periodic manner.
   • Effect: Intermittent forces can be effective in certain situations but may not provide the same level of predictability in tooth movement as continuous forces.
   • Examples: Temporary anchorage devices (TADs) that are activated periodically.

5. Directional Forces:

   •  Forces applied in specific directions to achieve desired tooth movement.
   • Effect: The direction of the force is critical in determining the type of movement (e.g., tipping, bodily movement, rotation) that occurs.
   • Examples: Using springs or elastics to move teeth mesially, distally, buccally, or lingually.

Orthopaedic appliances in dentistry are devices used to modify the growth of the jaws and align teeth by applying specific forces. These appliances utilize light orthodontic forces (50-100 grams) for tooth movement and orthopedic forces to induce skeletal changes, effectively guiding dental and facial development.

Orthopaedic appliances are designed to correct skeletal discrepancies and improve dental alignment by applying forces to the jaws and teeth. They are particularly useful in growing patients to influence jaw growth and positioning.

• Types of Orthopaedic Appliances:

  • Headgear: Used to correct overbites and underbites by applying force to the upper jaw.
  • Protraction Face Mask: Applies anterior force to the maxilla to correct retrusion.
  • Chin Cup: Restricts forward and downward growth of the mandible.
  • Functional Appliances: Such as the Herbst appliance, which helps in correcting overbites by repositioning the jaw.

Mechanisms of Action

• Force Application: Orthopaedic appliances apply heavy forces (300-500 grams) to the skeletal structures, which can alter the magnitude and direction of bone growth.
• Anchorage: These appliances often use teeth as handles to transmit forces to the underlying skeletal structures, requiring adequate anchorage from extraoral sites like the skull or neck.
• Intermittent Forces: The use of intermittent heavy forces is crucial, as it allows for skeletal changes while minimizing dental movement.

Indications for Use

• Skeletal Malocclusions: Effective for treating Class II and Class III malocclusions.
• Growth Modification: Used to guide the growth of the maxilla and mandible in children and adolescents.
• Space Management: Helps in creating space for proper alignment of teeth and preventing crowding.

Advantages of Orthopaedic Appliances

1. Non-Surgical Option: Provides a non-invasive alternative to surgical interventions for correcting skeletal discrepancies.
2. Guides Growth: Can effectively guide the growth of the jaws, leading to improved facial aesthetics and function.
3. Versatile Applications: Suitable for a variety of orthodontic issues, including overbites, underbites, and crossbites.

Limitations of Orthopaedic Appliances

1. Patient Compliance: The success of treatment heavily relies on patient adherence to wearing the appliance as prescribed.
2. Discomfort: Patients may experience discomfort or difficulty adjusting to the appliance initially.
3. Limited Effectiveness: May not be suitable for all cases, particularly those requiring significant tooth movement or complex surgical corrections.

Myofunctional Appliances

• Myofunctional appliances are removable or fixed devices that aim to correct dental and skeletal discrepancies by promoting proper oral and facial muscle function. They are based on the principles of myofunctional therapy, which focuses on the relationship between muscle function and dental alignment.

1. Mechanism of Action:

   • These appliances work by encouraging the correct positioning of the tongue, lips, and cheeks, which can help guide the growth of the jaws and the alignment of the teeth. They can also help in retraining oral muscle habits that may contribute to malocclusion, such as thumb sucking or mouth breathing.

Types of Myofunctional Appliances

1. Functional Appliances:

   • Bionator: A removable appliance that encourages forward positioning of the mandible and helps in correcting Class II malocclusions.
   • Frankel Appliance: A removable appliance that modifies the position of the dental arches and improves facial aesthetics by influencing muscle function.
   • Activator: A functional appliance that promotes mandibular growth and corrects dental relationships by positioning the mandible forward.

2. Tongue Retainers:

   • Devices designed to maintain the tongue in a specific position, often used to correct tongue thrusting habits that can lead to malocclusion.

3. Mouthguards:

   • While primarily used for protection during sports, certain types of mouthguards can also be designed to promote proper tongue posture and prevent harmful oral habits.

4. Myobrace:

   • A specific type of myofunctional appliance that is used to correct dental alignment and improve oral function by encouraging proper tongue posture and lip closure.

Indications for Use

• Malocclusions: Myofunctional appliances are often indicated for treating Class II and Class III malocclusions, as well as other dental alignment issues.
• Oral Habits: They can help in correcting harmful oral habits such as thumb sucking, tongue thrusting, and mouth breathing.
• Facial Growth Modification: These appliances can be used to influence the growth of the jaws in growing children, promoting a more favorable dental and facial relationship.
• Improving Oral Function: They can enhance functions such as chewing, swallowing, and speech by promoting proper muscle coordination.

Advantages of Myofunctional Appliances

1. Non-Invasive: Myofunctional appliances are generally non-invasive and can be a more comfortable option for patients compared to fixed appliances.
2. Promotes Natural Growth: They can guide the natural growth of the jaws and teeth, making them particularly effective in growing children.
3. Improves Oral Function: By retraining oral muscle function, these appliances can enhance overall oral health and function.
4. Aesthetic Appeal: Many myofunctional appliances are less noticeable than traditional braces, which can be more appealing to patients.

Limitations of Myofunctional Appliances

1. Compliance Dependent: The effectiveness of myofunctional appliances relies heavily on patient compliance. Patients must wear the appliance as prescribed for optimal results.
2. Limited Scope: While effective for certain types of malocclusions, myofunctional appliances may not be suitable for all cases, particularly those requiring significant tooth movement or surgical intervention.
3. Adjustment Period: Patients may experience discomfort or difficulty adjusting to the appliance initially, which can affect compliance.