Restoration of Carious Primary Teeth

Dental caries in primary (deciduous) teeth is one of the most common oral health problems among children worldwide. The main goal of restorative treatment in these teeth is not just to remove decay but also to restore function, aesthetics, and comfort while maintaining the tooth in the dental arch until its natural exfoliation. The process of restoring primary teeth requires careful consideration of the anatomy of these teeth, the behavior of young patients, and the appropriate choice of materials and techniques.

Importance of Accurate Pre-Operative Assessment

Before any restorative treatment begins, a thorough pre-operative assessment is essential. This includes a complete history, visual and tactile examination, and appropriate radiographs to evaluate the extent of the lesion and the proximity to the pulp.

An accurate treatment plan (often abbreviated as Rx plan) is developed based on these findings. The treatment plan should take into account:

• The child’s age and cooperation level
• The extent of caries and pulpal involvement
• The tooth’s strategic importance (for space maintenance and function)
• The stage of root resorption and time to exfoliation
• The presence of other carious or infected teeth

A well-formulated plan enables treatment to be completed efficiently and with minimal stress to the child.

Local Anaesthesia and Pain Management

Local anaesthesia (LA) is crucial for ensuring comfort during restorative procedures. The success of the treatment often depends on the effectiveness of anaesthesia and the child’s cooperation. The choice of LA technique depends on the tooth being treated:

• Infiltration is effective for most maxillary teeth and mandibular primary incisors.
• Nerve block may be required for mandibular molars due to denser bone.

Topical anaesthetic should always be applied before injection to minimize discomfort. Communication plays a key role — avoid words like “needle” or “injection,” and use child-friendly terms such as “sleepy juice” or “magic water.”

Isolation Techniques

Effective isolation is a vital part of restorative dentistry, especially in children. It ensures a clean and dry field, improves visibility, and enhances the quality and longevity of the restoration.

Rubber Dam

The rubber dam is considered the gold standard for isolation in restorative procedures. Its benefits include:

• Protection of the airway
• Improved visibility and moisture control
• Prevention of contamination
• Better child management (less debris and water spray in the mouth)

While rubber dams can be challenging to use in uncooperative children, practicing gradual desensitization and using smaller frames can make the process easier. If a rubber dam cannot be used, alternatives like cotton rolls and saliva ejectors should be applied.

Alternatives to Rubber Dam

When rubber dam placement is not possible:

• Use saliva ejectors (whistle-tip or tubular type)
• Place cotton wool rolls in the buccal and lingual sulci
• Use a high-volume evacuator for moisture control

For anxious or very young children, a combination of cotton rolls, a saliva ejector, and a cooperative assistant may be adequate for shorter procedures.

Instrumentation

Restorative instruments for paediatric dentistry are chosen to accommodate smaller mouths and delicate teeth.

Burs

• High-speed burs: Pear-shaped (Nos. 330, 525) and short fissure burs (No. 557) are commonly used for cavity preparation.
• Slow-speed burs: A range of round and pear-shaped burs are used for caries removal. A small round bur is useful for access, while larger ones help in excavating the bulk of caries.

Handpieces

The miniature-head handpiece is especially useful in paediatric dentistry. It allows better visibility, reduced weight, and easier access to posterior teeth in small mouths. Some children may be frightened by the sound of the aspirator or high-speed handpiece, so “Tell-Show-Do” techniques should be used to familiarize them with the instruments.

Principles of Cavity Preparation

The design of a cavity in a primary tooth must take into account the thinner enamel, broader contact areas, and larger pulp chambers of these teeth compared to permanent teeth. Over-extension or deep cavity preparation may easily lead to pulp exposure.

Outline Form

The outline form should:

• Include all carious areas and undermined enamel
• Be limited to affected fissures — unnecessary extension for prevention is no longer recommended
• Allow adequate access for caries removal and placement of restorative material

Caries Removal

• Start with the amalgam-dentin junction (ADJ), removing all carious dentin from the walls and floor.
• Remove caries progressively, ensuring that no infected dentin remains.
• If caries is deep, proceed carefully to avoid pulp exposure.

Retention and Resistance Form

While adhesive materials (like glass ionomer cement) bond chemically to tooth structure, some mechanical retention is still desirable. The cavity should have a slight occlusal convergence — that is, the base of the cavity is wider than the occlusal opening to prevent dislodgement.

Material Selection for Intracoronal Restorations

Choosing the right restorative material is one of the most important decisions in paediatric dentistry. The main options are glass ionomer cement (GIC), resin-modified GIC (RMGIC), compomer, composite resin, and in some cases, stainless steel crowns (SSCs) for extensive lesions.

Glass Ionomer Cement (GIC)

Advantages:

• Chemical adhesion to enamel and dentin
• Fluoride release (anticariogenic)
• Biocompatibility and ease of use

Disadvantages:

• Low wear resistance
• Susceptibility to moisture during setting
• Less suitable for stress-bearing areas

GIC is ideal for:

• Temporary restorations
• Class I and V cavities in low-stress areas
• Caries control in partially cooperative children

Resin-Modified Glass Ionomer Cement (RMGIC)

RMGIC combines the properties of glass ionomer and resin, offering:

• Better strength and wear resistance
• Faster setting (light-cured)
• Fluoride release and good adhesion

RMGIC performs excellently in primary teeth and is widely used for Class I and II restorations when isolation is adequate.

Compomer

A compomer is a hybrid of composite resin and GIC, designed to provide both fluoride release and good aesthetics.

• More moisture-sensitive than GIC but more durable.
• Used in small to moderate restorations.
• Commonly selected for aesthetic areas in anterior primary teeth.

Composite Resin

Composite resins provide excellent aesthetics but are more technique-sensitive.
They require:

• Excellent isolation (preferably with a rubber dam)
• Acid etching and bonding systems

While earlier studies reported poor performance in primary teeth, modern materials and bonding agents have improved outcomes significantly. Composites are best for small Class I or II restorations and aesthetic anterior fillings.

Amalgam (Less Frequently Used)

Dental amalgam was once the gold standard for posterior restorations due to its durability and ease of use. However, its use has greatly declined due to environmental concerns over mercury and the Minamata Treaty (2013).

As of July 2018, amalgam use in children under 15 and pregnant or breastfeeding women is restricted to cases where no suitable alternative exists. Many countries have moved toward mercury-free dentistry.

Stainless Steel Crowns (SSCs)

When caries are extensive, or the tooth has had pulp therapy, stainless steel crowns provide the most durable and reliable restoration. They offer:

• Complete coverage and protection from recurrent decay
• Excellent longevity
• Minimal sensitivity to moisture during placement

They are particularly recommended for multi-surface lesions, Class II cavities, and after pulpotomy or pulpectomy.

Common Reasons for Restoration Failure

Despite careful planning, restorations in primary teeth can fail for several reasons:

1. Recurrent Caries:
   Often due to incomplete caries removal or inadequate sealing of margins.
2. Poor Moisture Control:
   Particularly affects adhesive materials like composites and GICs.
3. Inadequate Mechanical Design:
   Failure to create proper retention and resistance form can lead to dislodgement.
4. Improper Finishing or Polishing:
   Rough surfaces retain plaque, increasing the risk of secondary caries.
5. High Occlusal Contacts:
   Can lead to fracture or dislodgement of the restoration.

Preventive strategies include thorough caries excavation, proper isolation, correct material selection, and checking occlusion at the end of the procedure.

Managing Child Behavior and Communication

Child cooperation is a cornerstone of successful paediatric dentistry. Each child’s emotional state, anxiety level, and understanding are unique. Using effective communication techniques can significantly improve cooperation.

Tell-Show-Do Technique

• Tell: Explain what will happen in simple, reassuring words.
• Show: Demonstrate the procedure using instruments in a non-threatening way.
• Do: Proceed with the treatment once the child understands and is comfortable.

Use of Child-Friendly Terms

Avoid intimidating words like “needle,” “drill,” or “injection.” Use “childrenese” — child-friendly analogies.
For example:

Such language reduces fear and builds trust.

Step-by-Step Procedure for Plastic Restoration in Primary Molars

1. Explain and reassure the child and parent.
   Describe the process simply and positively.
2. Administer local anaesthesia and wait for it to take effect.
3. Achieve isolation using rubber dam or cotton rolls.
4. Access the carious lesion with a pear-shaped or round bur.
   The cavity should follow the fissures of the tooth.
5. Remove caries completely, ensuring that all soft dentin is cleared.
6. Shape the cavity: The cavity should converge occlusally (base wider than the top). For large cavities, a stainless steel crown may be a better choice.
7. Wash and dry the cavity (avoid desiccation).
8. Place a lining such as hard-setting calcium hydroxide if using amalgam or if the cavity is deep.
9. Place and finish the restorative material according to manufacturer’s instructions.
10. Check occlusion to ensure no high points.
11. Reinforce positive behavior by praising the child and giving a sticker or badge.

Prevention of Future Caries

Restoration is only one part of caries management. Long-term prevention is essential. Parents and children should receive advice on:

• Brushing twice daily with fluoridated toothpaste
• Reducing sugary snacks and drinks
• Regular dental check-ups every six months
• Use of fluoride varnish or sealants for at-risk children

Key Clinical Tips

• Always use proper lighting and magnification if available.
• Work efficiently — children’s attention spans are short.
• When possible, complete treatment in one visit, but don’t rush.
• Begin with less challenging teeth to build the child’s confidence.
• Continuously communicate and reassure the child during treatment.

Conclusion

The restoration of carious primary teeth is a fundamental skill in paediatric dentistry. Success relies not only on technical knowledge but also on effective communication, behavior management, and clinical judgment. By understanding the principles of cavity design, mastering material selection, and maintaining a child-centered approach, practitioners can ensure durable restorations and positive dental experiences for young patients.

Ultimately, the goal is to preserve primary teeth until their natural exfoliation, maintain arch integrity, and promote a lifetime of good oral health habits.

References

1. McDonald, R. E., Avery, D. R., & Dean, J. A. (2016). McDonald and Avery’s Dentistry for the Child and Adolescent (10th ed.). St. Louis: Elsevier.
   → Comprehensive reference on cavity preparation, restorative materials, and behavior management in pediatric dentistry.
2. Mount, G. J., & Hume, W. R. (2005). Preservation and Restoration of Tooth Structure (2nd ed.). Oxford: Wright.
   → Key reference on minimally invasive cavity design and adhesive restorative materials.
3. Cameron, A. C., & Widmer, R. P. (2023). Handbook of Pediatric Dentistry (6th ed.). Elsevier.
   → Core handbook covering diagnosis, local anaesthesia, isolation, and restorative techniques in primary teeth.
4. Pinkham, J. R., Casamassimo, P. S., McTigue, D. J., Fields, H. W., & Nowak, A. J. (2014). Pediatric Dentistry: Infancy through Adolescence (5th ed.). St. Louis: Elsevier.
   → Excellent coverage of restorative procedures, treatment planning, and communication strategies with children.
5. Innes, N. P. T., et al. (2016). Management of carious lesions in primary teeth: International consensus recommendations. British Dental Journal, 221(10), 557–564.
   → International consensus on evidence-based management of caries in primary teeth.
6. Nair, M., et al. (2018). Restorative materials for primary teeth: A review of clinical trials. Journal of Clinical Pediatric Dentistry, 42(3), 177–184.
   → Evidence-based comparison of GIC, RMGIC, compomers, and composites in pediatric restorations.
7. American Academy of Pediatric Dentistry (AAPD). (2024). Guideline on Restorative Dentistry for Primary and Immature Permanent Teeth.
   Available at: www.aapd.org
   → Official clinical guidelines on cavity design, material choice, and restoration longevity in children.
8. Mjör, I. A., & Gordan, V. V. (2002). Failure, repair, and the longevity of restorations in general dental practice. Acta Odontologica Scandinavica, 60(1), 1–7.
   → Useful for understanding common causes of restoration failure.
9. World Health Organization (WHO). (2017). Minamata Convention on Mercury: Text and Annexes.
   → Reference for the global regulation restricting the use of dental amalgam in children and pregnant women.
10. Hollis, W., & Taylor, C. L. (2019). Isolation techniques in pediatric dentistry: A clinical review. International Journal of Paediatric Dentistry, 29(5), 477–484.
    → Practical review on the use of rubber dam and alternative isolation methods in children.
11. Berg, J. H., & Croll, T. P. (2015). Glass ionomer restorative materials: A status report for the American Journal of Dentistry. American Journal of Dentistry, 28(1), 11–23.
    → Source for evidence on the use of GIC and RMGIC in primary teeth.