Distal Shoe Space Maintainer

The distal shoe space maintainer is a fixed appliance used in pediatric dentistry to maintain space in the dental arch following the early loss or removal of a primary molar, particularly the second primary molar, before the eruption of the first permanent molar. This appliance helps to guide the eruption of the permanent molar into the correct position.

Indications

• Early Loss of Second Primary Molar:
  • The primary indication for a distal shoe space maintainer is the early loss or removal of the second primary molar prior to the eruption of the first permanent molar.
  • It is particularly useful in the maxillary arch, where bilateral space loss may necessitate the use of two appliances to maintain proper arch form and space.

Contraindications

1. Inadequate Abutments:

   • The presence of multiple tooth losses may result in inadequate abutments for the appliance, compromising its effectiveness.

2. Poor Patient/Parent Cooperation:

   • Lack of cooperation from the patient or parent can hinder the successful use and maintenance of the appliance.

3. Congenitally Missing First Molar:

   • If the first permanent molar is congenitally missing, the distal shoe may not be effective in maintaining space.

4. Medical Conditions:

   • Certain medical conditions, such as blood dyscrasias, congenital heart disease (CHD), rheumatic fever, diabetes, or generalized debilitation, may contraindicate the use of a distal shoe due to increased risk of complications.

Limitations/Disadvantages

1. Overextension Risks:

   • If the distal shoe is overextended, it can cause injury to the permanent tooth bud of the second premolar, potentially leading to developmental issues.

2. Underextension Risks:

   • If the appliance is underextended, it may allow the molar to tip into the space or over the band, compromising the intended space maintenance.

3. Epithelialization Prevention:

   • The presence of the distal shoe may prevent complete epithelialization of the extraction socket, which can affect healing.

4. Eruption Path Considerations:

   • Ronnermann and Thilander (1979) discussed the path of eruption, noting that drifting of teeth occurs only after eruption through the bone covering. The lower first molar typically erupts occlusally to contact the distal crown surface of the primary molar, using that contact for uprighting. Isolated cases of ectopic eruption should be considered when evaluating the eruption path.

The American Academy of Pediatric Dentistry (AAPD) Caries Risk Assessment Tool is designed to evaluate a child's risk of developing dental caries (cavities). The tool considers various factors to categorize a child's risk level as low, moderate, or high.

Low Risk:
- No carious (cavitated) teeth in the past 24 months
- No enamel white spot lesions (initial stages of tooth decay)
- No visible dental plaque
- Low incidence of gingivitis (mild gum inflammation)
- Optimal exposure to fluoride (both systemic and topical)
- Limited consumption of simple sugars (at meal times only)

Moderate Risk:
- Carious teeth in the past 12 to 24 months
- One area of white spot lesion
- Gingivitis present
- Suboptimal systemic fluoride exposure (e.g., not receiving fluoride supplements or living in a non-fluoridated water area)
- One or two between-meal exposures to simple sugars

High Risk:
- Carious teeth in the past 12 months
- More than one area of white spot lesion
- Visible dental plaque
- Suboptimal topical fluoride exposure (not using fluoridated toothpaste or receiving professional fluoride applications)
- Presence of enamel hypoplasia (developmental defect of enamel)
- Wearing orthodontic or dental appliances that may increase caries risk
- Active caries in the mother, which can increase the child's risk due to oral bacteria transmission
- Three or more between-meal exposures to simple sugars

Photostimulable Phosphors (PSPs) in Digital Imaging

• Photostimulable phosphors (PSPs), also known as storage phosphors, are materials used in digital imaging for the acquisition of radiographic images. They serve as an alternative to traditional film-based radiography.

Characteristics of PSPs

• Storage Mechanism: Unlike conventional screen materials used in panoramic or cephalometric imaging, PSPs do not fluoresce immediately upon exposure to x-ray photons. Instead, they capture and store the incoming x-ray photon information as a latent image.

• Latent Image: The latent image is similar to that found in traditional film radiography, where the image is not visible until processed.

Image Acquisition Process

1. Exposure:

   • The PSP plate is exposed to x-rays, which causes the phosphor material to absorb and store the energy from the x-ray photons.

2. Scanning:

   • After exposure, the PSP plate is scanned by a laser beam in a drum scanner. This process is crucial for retrieving the stored image information.

3. Energy Release:

   • The laser scanning excites the phosphor, causing it to release the stored energy as an electronic signal. This signal represents the latent image captured during the x-ray exposure.

4. Digitalization:

   • The electronic signal is then digitized, with various gray levels assigned to different points on the curve. This process creates the final image information that can be viewed and analyzed.

Advantages of PSP Systems

• Image Quality: PSPs can produce high-quality images with a wide dynamic range, allowing for better visualization of anatomical structures.

• Reusability: PSP plates can be reused multiple times, making them a cost-effective option for dental practices.

• Compatibility: PSP systems can be integrated into existing digital imaging workflows, providing flexibility for dental professionals.

Available PSP Imaging Systems

• Soredex: OpTime
• AirTechniques: Scan X
• Gendex: Denoptix

These systems offer various features and capabilities, allowing dental practices to choose the best option for their imaging needs.

Classification of Cerebral Palsy

Cerebral palsy (CP) is a group of neurological disorders that affect movement, muscle tone, and motor skills. The classification of cerebral palsy is primarily based on the type of neuromuscular dysfunction observed in affected individuals. Below is an outline of the main types of cerebral palsy, along with their basic characteristics.

1. Spastic Cerebral Palsy (Approximately 70% of Cases)

• Definition: Characterized by hypertonicity (increased muscle tone) and exaggerated reflexes.
• Characteristics:
  • A. Hyperirritability of Muscles: Involved muscles exhibit exaggerated contractions when stimulated.
  • B. Tense, Contracted Muscles:
    • Example: Spastic Hemiplegia affects one side of the body, with the affected hand and arm flexed against the trunk. The leg may be flexed and internally rotated, leading to a limping gait with circumduction of the affected leg.
  • C. Limited Neck Control: Difficulty controlling neck muscles results in head rolling.
  • D. Trunk Muscle Control: Lack of control in trunk muscles leads to difficulties in maintaining an upright posture.
  • E. Coordination Issues: Impaired coordination of intraoral, perioral, and masticatory muscles can result in:
    • Impaired chewing and swallowing
    • Excessive drooling
    • Persistent spastic tongue thrust
    • Speech impairments

2. Dyskinetic Cerebral Palsy (Athetosis and Choreoathetosis) (Approximately 15% of Cases)

• Definition: Characterized by constant and uncontrolled movements.
• Characteristics:
  • A. Uncontrolled Motion: Involved muscles exhibit constant, uncontrolled movements.
  • B. Athetoid Movements: Slow, twisting, or writhing involuntary movements (athetosis) or quick, jerky movements (choreoathetosis).
  • C. Neck Muscle Involvement: Excessive head movement due to hypertonicity of neck muscles, which may cause the head to be held back, with the mouth open and tongue protruded.
  • D. Jaw Involvement: Frequent uncontrolled jaw movements or severe bruxism (teeth grinding).
  • E. Hypotonicity of Perioral Musculature:
    • Symptoms include mouth breathing, tongue protrusion, and excessive drooling.
  • F. Facial Grimacing: Involuntary facial expressions may occur.
  • G. Chewing and Swallowing Difficulties: Challenges in these areas are common.
  • H. Speech Problems: Communication difficulties may arise.

3. Ataxic Cerebral Palsy (Approximately 5% of Cases)

• Definition: Characterized by poor coordination and balance.
• Characteristics:
  • A. Incomplete Muscle Contraction: Involved muscles do not contract completely, leading to partial voluntary movements.
  • B. Poor Balance and Coordination: Individuals may exhibit a staggering or stumbling gait and difficulty grasping objects.
  • C. Tremors: Possible tremors or uncontrollable trembling when attempting voluntary tasks.

4. Mixed Cerebral Palsy (Approximately 10% of Cases)

• Definition: A combination of characteristics from more than one type of cerebral palsy.
• Example: Mixed spastic-athetoid quadriplegia, where features of both spastic and dyskinetic types are present.

Space Maintainers: A fixed or removable appliance designed to maintain the space left by a prematurely lost tooth, ensuring proper alignment and positioning of the permanent dentition.

Importance of Primary Teeth

• Primary teeth serve as the best space maintainers for the permanent dentition. Their presence is crucial for guiding the eruption of permanent teeth and maintaining arch integrity.

Consequences of Space Loss

When a tooth is lost prematurely, the space can change significantly within a six-month period, leading to several complications:

• Loss of Arch Length: This can result in crowding of the permanent dentition.
• Impaction of Permanent Teeth: Teeth may become impacted if there is insufficient space for their eruption.
• Esthetic Problems: Loss of space can lead to visible gaps or misalignment, affecting a child's smile.
• Malocclusion: Improper alignment of teeth can lead to functional issues and bite problems.

Indications for Space Maintainers

Space maintainers are indicated in the following situations:

1. If the space shows signs of closing.
2. If using a space maintainer will simplify future orthodontic treatment.
3. If treatment for malocclusion is not indicated at a later date.
4. When the space needs to be maintained for two years or more.
5. To prevent supra-eruption of opposing teeth.
6. To improve the masticatory system and restore dental health.

Contraindications for Space Maintainers

Space maintainers should not be used in the following situations:

1. If radiographs show that the succedaneous tooth will erupt soon.
2. If one-third of the root of the succedaneous tooth is already calcified.
3. When the space left is greater than what is needed for the permanent tooth, as indicated radiographically.
4. If the space shows no signs of closing.
5. When the succedaneous tooth is absent.

Classification of Space Maintainers

Space maintainers can be classified into two main categories:

1. Fixed Space Maintainers

•  These are permanently attached to the teeth and cannot be removed by the patient. Examples include band and loop space maintainers.

  Common types include:

  • Band and Loop Space Maintainer:

    • A metal band is placed around an adjacent tooth, and a wire loop extends into the space of the missing tooth. This is commonly used for maintaining space after the loss of a primary molar.

  • Crown and Loop Space Maintainer:

    • Similar to the band and loop, but a crown is placed on the adjacent tooth instead of a band. This is used when the adjacent tooth requires a crown.

  • Distal Shoe Space Maintainer:

    • This is used when a primary second molar is lost before the eruption of the permanent first molar. It consists of a metal band on the first molar with a metal extension (shoe) that guides the eruption of the permanent molar.

  • Transpalatal Arch:

    • A fixed appliance that connects the maxillary molars across the palate. It is used to maintain space and prevent molar movement.

  • Nance Appliance:

    • Similar to the transpalatal arch, but it has a small acrylic button that rests against the anterior palate. It is used to maintain space in the upper arch.

2. Removable Space Maintainers

• These can be taken out by the patient and are typically used when more than one tooth is lost. They can also serve to replace occlusal function and improve esthetics.

  Common types include:

  • Removable Partial Denture:

    • A prosthetic device that replaces one or more missing teeth and can be removed by the patient. It can help maintain space and restore function and esthetics.

  • Acrylic Space Maintainer:

    • A simple acrylic appliance that can be used to maintain space. It is often used in cases where esthetics are a concern.

  • Functional Space Maintainers:

    • These are designed to provide occlusal function while maintaining space. They may include components that allow for chewing and speaking.

Types of Removable Space Maintainers

• Non-functional: Typically used when more than one tooth is lost.
• Functional: Designed to provide occlusal function.

Advantages of Removable Space Maintainers

1. Easy to clean and maintain proper oral hygiene.
2. Maintains vertical dimension.
3. Can be worn part-time, allowing circulation of blood to soft tissues.
4. Creates room for permanent teeth.
5. Helps prevent the development of tongue thrust habits into the extraction space.

Disadvantages of Removable Space Maintainers

1. May be lost or broken by the patient.
2. Uncooperative patients may not wear the appliance.
3. Lateral jaw growth may be restricted if clasps are incorporated.
4. May cause irritation of the underlying soft tissues.

Stainless Steel Crowns

Stainless steel crowns (SSCs) are a common restorative option for primary teeth, particularly in pediatric dentistry. They are especially useful for teeth with extensive carious lesions or structural damage, providing durability and protection for the underlying tooth structure.

Indications for Stainless Steel Crowns

• Primary Incisors or Canines:
  • SSCs are indicated for primary incisors or canines that have extensive proximal lesions, especially when the incisal portion of the tooth is involved.
  • They are particularly beneficial in cases where traditional restorative materials (like amalgam or composite) may not provide adequate strength or longevity.

Crown Selection and Preparation

1. Crown Selection:

   • An appropriate size of stainless steel crown is selected based on the dimensions of the tooth being restored.

2. Contouring:

   • The crown is contoured at the cervical margin to ensure a proper fit and to minimize the risk of gingival irritation.

3. Polishing:

   • The crown is polished to enhance its surface finish, which can help reduce plaque accumulation and improve esthetics.

4. Cementation:

   • The crown is cemented into place using a suitable dental cement, ensuring a secure fit even on teeth that have undergone significant carious structure removal.

Advantages of Stainless Steel Crowns

• Retention:
  • SSCs provide excellent retention and can remain in place even when extensive portions of carious tooth structure have been removed.
• Durability:
  • They are highly durable and can withstand the forces of mastication, making them ideal for primary teeth that are subject to wear and tear.

Esthetic Considerations

• Esthetic Limitations:

  • One of the drawbacks of stainless steel crowns is their metallic appearance, which may not meet the esthetic requirements of some children and their parents.

• Open-Face Stainless Steel Crowns:

  • To address esthetic concerns, a technique known as the open-face stainless steel crown can be employed.
  • In this technique, most of the labial metal of the crown is cut away, creating a labial "window."
  • This window is then restored with composite resin, allowing for a more natural appearance while still providing the strength and durability of the stainless steel crown.