Effective Treatment of Primary Anterior Caries

A strip crown technique for durable, esthetic results

Carla Cohn, DMD

Anterior caries in primary teeth present unique challenges for restoration for the dental practitioner. Although restorations placed in pediatric patients are technically temporary, they are often required to last for years, meaning that the need for strength and durability—as well as esthetics—should not be underestimated.

Pediatric Treatment Challenges

Age is the first and foremost of the special challenges when working with pediatric patients. Very often children with anterior caries present at the young age of 2 or 3 years, once a problem has become evident to the parent or sometimes to the primary healthcare practitioner.

Demineralization of primary teeth is significantly faster than that of permanent teeth, leading to the urgency for timely treatment.¹ Although primary incisors are among the first to exfoliate, they do have a very significant “lifespan.” On average, central incisors begin to exfoliate naturally between the ages of 7 and 8 years, and lateral incisors exfoliate between the ages of 8 and 9 years.²

Patient cooperation is another significant factor that must be taken into account. On occasion, young children have the potential to be pre-cooperative or uncooperative. Many times it is the practitioner who is the apprehensive one, however. The mastery of the clinical procedure along with some simple behavior management techniques can mean the difference between treatment success and failure.

Patient behavior after restoration is another area to consider when planning treatment. Children will not and cannot be expected to be gentle with their teeth. Anterior teeth take a lot of wear and tear, and restorations must be durable and reliable enough to be “kid tough.” In addition, up to 38% of children are bruxers.³ Bruxing leads to flexure of the tooth and the ultimate failure of an intracoronal restoration.

Intracoronal restorations of primary anterior teeth rely upon retention from bond to enamel or dentin as the case may be. Any mechanical retention incorporated into the preparation will also help with retention; however, flexure is a problem. Due to the morphology and size of primary teeth as well as the thickness of enamel, retention and adhesive strength are difficult to predict.

Signifcance of Primary Anterior Caries

Anterior caries in primary dentition is smooth surface caries and is classified as S-ECC, or severe early childhood caries.⁴ S-ECC is a disease, and often the posterior dentition is also affected. Practitioners should always address caries prevention and risk management.

Because of the challenges presented in working with children, treating anterior caries in the primary dentition is a situation unlike any other. Imagine for a moment a situation in which you personally had anterior caries. Would you even consider leaving it untreated for up to 7 or 8 years given the pain on chewing, unsightly smile, potential for infection, and subsequent damage to surrounding tissues and dentition? If that scenario seems impossible for an adult, why leave a child in that state?

Case Presentation

A 3-year-old girl presented with S-ECC; her anterior teeth were asymptomatic and deemed restorable (Figure 1). Restorative treatment options included preveneered stainless steel crowns, prefabricated zirconia crowns, or strip crowns. In this case, the treatment plan chosen was strip crown placement. Strip crowns are filled with composite, glass ionomer, resin-modified glass ionomer, or giomer. Deciding which filling material to choose requires a closer look at the properties of each material.

Material Selection

Composite resin is the most commonly used tooth-colored filling material in North America. Composite resin is very esthetic and available in a wide range of shades. It is often already available in the armamentarium of the general practitioner. Composite resin is a very technique-sensitive material, however, and any contamination will compromise the success of the treatment. Many excellent composite materials are available, including Grandio®SO (VOCO America, Inc., www.voco.com/us), Kalore™ (GC America, www.gcamerica.com), and Venus® (Heraeus Kulzer, www.heraeus-dental.com).

Glass ionomers and resin-modified glass ionomers are incredibly versatile materials that offer bioactive properties. The bioactive factor allows for fluoride release and recharge. Glass ionomers and resin-modified glass ionomers offer a chemical as well as a mechanical bond, which is particularly relevant when bonding to dentin. The material also does not require a completely dry field. On the contrary, it requires water to complete its reaction and set, and is therefore more forgiving with respect to contamination. These materials do not display strength as high as composite materials, but they can be an excellent fill material for this procedure. Glass ionomers and resin-modified glass ionomers include GC Fuji IX™ and Fuji II™ LC (GC America) and Riva SC and Riva LC (SDI, www.sdi.com.au/en-us).

Giomers are a unique category of filling materials.⁵ They consist of a resin-based composite with a filler of surface pre-reacted glass particles. Giomers have an acid-reactive fluoride-containing core, a glass ionomer phase, and a surface-modified layer. Like composite resins, the handling and esthetics are superb. It is important to have a dry field when working with giomers.

Like glass ionomers and resin-modified glass ionomers, they are bioactive in their ability to release fluoride and recharge from external sources.^6,7 In addition, giomer restorations have the unique ability to resist plaque formation due to a film that forms on the surface of the giomer when it contacts saliva. This film originates from the giomer fillers and acts to inhibit bacterial adhesion.⁸ The giomers will also neutralize and buffer acids in the mouth.⁹ Furthermore, it has been shown that remineralization occurs at surfaces adjacent to the giomers.¹⁰ To date, the Beautifil® line of products (Shofu Dental Corporation, www.shofu.com) are the only commercially available giomers.

Procedure

In this case, orthodontic separators were placed around the cervical area subgingivally to control hemorrhage after isolation.¹¹ Reduction is carried out most effortlessly if incisal and supragingival circumferential reduction are completed first. This way, the field of vision is clearest (Figure 2).

Following supragingival circumferential reduction of approximately 20%, decay was excavated; this can be accomplished either with a rotary instrument, a large round slow-speed bur, or a sharp spoon excavator (Figure 3). If necessary, pulpal therapy would be done at this time. Circumferential preparation is completed approximately 1 to 2 mm subgingivally, ensuring that a featheredge is achieved (Figure 4).

Strip crown forms were fitted and vented incisally to allow for a void-free bulk fill. Strip crown forms from Success Essentials (Success Essentials Pediatric Strip Crowns, Appliance Therapy Group, www.appliancetherapy.com) were used in this case. They are collarless and easily identifiable by sticker labels that adhere to the palatal of the crown form. It is imperative to fit these strip crowns at the same time to ensure a successful outcome (Figure 5).

Once an acceptable fit was achieved, the teeth were washed and dried. The teeth were etched with phosphoric acid for 10 to 15 seconds, then washed and dried again. Adhesive was placed on all surfaces and cured. A thin layer of Beautifil Flow Plus giomer was placed as a base on all surfaces. This layer was not cured separately as in the “modified snowplow technique.”¹² The crown forms were then filled with Beautifil II giomer and placed firmly over the prepared teeth. Excess can be removed prior to curing if possible (Figure 6 and Figure 7).

Strip crown forms and separators were then removed, and the restoration was polished and finished. Immediately postoperatively, hemorrhage was evident. Within 2 weeks of regular home care, healing was complete (Figure 8).

Conclusion

The technique described allows for effective treatment of primary anterior decay. The circumferential fill offers complete coverage of the tooth and strength of the material due to the inherent design. Any shrinkage that may occur will be advantageous, as the material will shrink inwards to the tooth surface. Compared with prefabricated restorative options, the strip crown technique offers more flexibility for customizing both shape and shade. Finally, any fractures can be repaired conservatively, by simply bonding more material. Durability makes the strip crowns an extremely good treatment choice for anterior primary caries, provided that adequate tooth structure remains after caries removal.¹³ Parental satisfaction for strip crown procedures is excellent.¹⁴ Strip crown procedures use materials and techniques familiar to all general practitioners, allowing successful treatment outcomes for primary anterior decay.

Disclosure

The author received an honorarium from Shofu for this article.

References

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About the Author

Carla Cohn, DMD

Private Practice

Winnipeg, Manitoba, Canada