Tooth Replantation and Avulsion Injuries

Tooth avulsion is a dental emergency that occurs when a tooth is completely displaced from its socket. The success of replantation, which involves placing the avulsed tooth back into its socket, is influenced by several factors, including the time elapsed since the avulsion and the condition of the periodontal ligament (PDL) tissue.

Key Factors Influencing Replantation Success

1. Time Elapsed Since Avulsion:

   • The length of time between the loss of the tooth and its replantation is critical. The sooner a tooth can be replanted, the better the prognosis for retention and vitality.
   • Prognosis Statistics:
     • Replantation within 30 minutes: Approximately 90% of replanted teeth show no evidence of root resorption after 2 or more years.
     • Replantation after 2 hours: About 95% of these teeth exhibit root resorption.

2. Condition of the Tooth:

   • The condition of the tooth at the time of replantation, particularly the health of the periodontal ligament tissue remaining on the root surface, significantly affects the outcome.
   • Immediate replacement of a permanent tooth can sometimes lead to vitality and indefinite retention, but this is not guaranteed.

3. Temporary Measure:

   • While replantation can be successful, it should generally be viewed as a temporary solution. Many replanted teeth may be retained for 5 to 10 years, with a few lasting a lifetime, but others may fail shortly after replantation.

Common Avulsion Injuries

• Most Commonly Avulsed Tooth: The maxillary central incisor is the tooth most frequently avulsed in both primary and permanent dentition.
• Demographics:
  • Avulsion injuries typically involve a single tooth and are three times more common in boys than in girls.
  • The highest incidence occurs in children aged 7 to 9 years, coinciding with the eruption of permanent incisors.
• Structural Factors: The loosely structured periodontal ligament surrounding erupting teeth may predispose them to complete avulsion.

Recommendations for Management of Avulsed Teeth

1. Immediate Action: If a tooth is avulsed, it should be replanted as soon as possible. If immediate replantation is not feasible, the tooth should be kept moist.

   • Storage Options: The tooth can be stored in:
     • Cold milk (preferably whole milk)
     • Saline solution
     • Patient's own saliva (by placing it in the buccal vestibule)
     • A sterile saline solution
   • Avoid: Storing the tooth in water, as this can damage the periodontal ligament cells.

2. Professional Care: Seek dental care immediately after an avulsion injury to ensure proper replantation and follow-up care.

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.

Growth Theories

Understanding the growth of craniofacial structures is crucial in pedodontics, as it directly influences dental development, occlusion, and treatment planning. Various growth theories have been proposed to explain the mechanisms behind craniofacial growth, each with its own assumptions and clinical implications.

Growth Theories Overview

1. Genetic Theory (Brodle, 1941)

• Assumption: Genes control all aspects of growth.
• Application: While genetic factors play a role, external factors significantly modify growth, reducing the sole impact of genetics. Inheritance is polygenic, influencing predispositions such as Class III malocclusion.

2. Scott’s Hypothesis (1953)

• Assumption: Cartilage has innate growth potential, which is later replaced by bone.
• Application:
  • Mandibular growth is likened to long bone growth, with the condyles acting as diaphysis.
  • Recent studies suggest that condylar growth is primarily reactive rather than innate.
  • Maxillary growth is attributed to the translation of the nasomaxillary complex.

3. Sutural Dominance Theory (Sicher, 1955)

• Assumption: Sutural connective tissue proliferation leads to appositional growth.
• Application:
  • Maxillary growth is explained by pressure from sutural growth.
  • Limitations include inability to explain:
    • Lack of growth in suture transplantation.
    • Growth in cleft palate cases.
    • Sutural responses to external influences.

4. Moss’s Functional Theory (1962)

• Assumption: Functional matrices (capsular and periosteal) control craniofacial growth, with bone responding passively.
• Application:
  • Examples include excessive cranial vault growth in hydrocephalus cases, illustrating the influence of functional matrices on bone growth.

5. Van Limborgh’s Theory (1970)

• Assumption: Skeletal morphogenesis is influenced by:
  1. Intrinsic genetic factors
  2. Local epigenetic factors
  3. General epigenetic factors
  4. Local environmental factors
  5. General environmental factors
• Application:
  • Highlights the interaction between genetic and environmental factors, emphasizing that muscle and soft tissue growth also has a genetic component.
  • Predicting facial dimensions based on parental studies is limited due to the polygenic and multifactorial nature of growth.

6. Petrovic’s Hypothesis (1974, Cybernetics)

• Assumption: Primary cartilage growth is influenced by differentiation of chondroblasts, while secondary cartilage has both direct and indirect effects on growth.
• Application:
  • Explains the action of functional appliances on the condyle.
  • The upper arch serves as a mold for the lower arch, facilitating optimal occlusion.

7. Neurotropism (Behrents, 1976)

• Assumption: Nerve impulses, through axoplasmic transport, have direct growth potential and influence soft tissue growth indirectly.
• Application:
  • The effect of neurotropism on growth is reported to be negligible, suggesting limited clinical implications.

Clinical Implications

Understanding these growth theories is essential for pediatric dentists in several ways:

• Diagnosis and Treatment Planning: Knowledge of growth patterns aids in diagnosing malocclusions and planning orthodontic interventions.
• Timing of Interventions: Recognizing the stages of growth can help in timing treatments such as extractions, space maintainers, and orthodontic appliances.
• Predicting Growth Outcomes: Awareness of genetic and environmental influences can assist in predicting treatment outcomes and managing patient expectations.

Polycarbonate Crowns in Pedodontics

Polycarbonate crowns are commonly used in pediatric dentistry, particularly for managing anterior teeth affected by nursing bottle caries. These crowns serve as temporary fixed prostheses for primary teeth, providing a functional and aesthetic solution until the natural teeth exfoliate. This lecture will discuss the indications, contraindications, and advantages of polycarbonate crowns in pedodontic practice.

Nursing Bottle Caries

• Definition: Nursing bottle caries, also known as early childhood caries, is a condition characterized by the rapid demineralization of the anterior teeth, primarily affecting the labial surfaces.
• Progression: The lesions begin on the labial face of the anterior teeth and can lead to extensive demineralization, affecting the entire surface of the teeth.
• Management Goal: The primary objective is to stabilize the lesions without attempting a complete reconstruction of the coronal anatomy.

Treatment Approach

1. Preparation of the Lesion:

   • The first step involves creating a clean periphery around the carious lesion using a small round bur.
   • Care should be taken to leave the central portion of the affected dentin intact to avoid pulp exposure.
   • This preparation allows for effective ion exchange with glass ionomer materials, facilitating a good seal.

2. Use of Polycarbonate Crowns:

   • Polycarbonate crowns are indicated as temporary crowns for deciduous anterior teeth that will eventually exfoliate.
   • They provide a protective covering for the tooth while maintaining aesthetics and function.

Contraindications for Polycarbonate Crowns

Polycarbonate crowns may not be suitable in certain situations, including:

• Severe Bruxism: Excessive grinding can lead to premature failure of the crown.
• Deep Bite: A deep bite may cause undue stress on the crown, leading to potential fracture or dislodgment.
• Excessive Abrasion: High levels of wear can compromise the integrity of the crown.

Advantages of Polycarbonate Crowns

Polycarbonate crowns offer several benefits in pediatric dentistry:

• Time-Saving: The application of polycarbonate crowns is relatively quick, making them efficient for both the clinician and the patient.
• Ease of Trimming: These crowns can be easily trimmed to achieve the desired fit and contour.
• Adjustability: They can be adjusted with pliers, allowing for modifications to ensure proper seating and comfort for the patient.

Colla Cote

Colla Cote is a biocompatible, soft, white, and pliable sponge derived from bovine collagen. It is designed for various dental and surgical applications, particularly in endodontics. Here are its key features and benefits:

• Biocompatibility: Colla Cote is made from natural bovine collagen, ensuring compatibility with human tissue and minimizing the risk of adverse reactions.

• Moisture Tolerance: This absorbable collagen barrier can be effectively applied to moist or bleeding canals, making it suitable for use in challenging clinical situations.

• Extravasation Prevention: Colla Cote is specifically designed to prevent or reduce the extravasation of root canal filling materials during primary molar pulpectomies, enhancing the success of the procedure.

• Versatile Applications: Beyond endodontic therapy, Colla Cote serves as a scaffold for bone growth, making it useful in various surgical contexts, including wound management.

• Absorbable Barrier: As an absorbable material, Colla Cote gradually integrates into the body, eliminating the need for removal and promoting natural healing processes.

Classification of Early Childhood Caries (ECC)

• Type 1 ECC (Mild to Moderate)

  • Affects molars and incisors
  • Typically seen in children aged 2-5 years

• Type 2 ECC (Moderate to Severe)

  • Characterized by labiolingual caries affecting maxillary incisors, with or without molar involvement
  • Usually observed soon after the first tooth erupts
  • Mandibular incisors remain unaffected
  • Often caused by inappropriate bottle feeding

• Type 3 ECC (Severe)

  • Involves all primary teeth
  • Commonly seen in children aged 3-5 years