Composite Strip Crowns

Composite strip crowns are composite filled celluloid crowns forms. They have become a popular method of restoring primary anterior teeth because they provide superior aesthetics as compared to other forms of anterior tooth coverage. Composite strip crowns rely on dentin and enamel adhesion for retention. Therefore the lack of tooth structure, the presence of moisture or hemorrhage contributes to compromised retention. They are less resistant to wear and fracture more readily than other anterior full coverage restorations. A 2002 study by Tate, et al., found that composite strip crowns had a failure rate of 51%, compared to an 8% failure rate of stainless steel crowns.4

With a cooperative patient, the time required for placement is comparable to that of a stainless steel crown and less than veneered and zirconia crowns.

Advantages

  • It provides superior aesthetics.
  • The cost of materials are reasonable (approximately $6/crown).
  • The time for placement is reasonable.

Disadvantages

  • It is extremely technique sensitive.
  • It is not as durable or retentive as stainless steel/open faced crowns, pre-veneered crowns or zirconia crowns and is not recommended on patients with a bruxism habit or a deep bite.
  • Adequate moisture control might be difficult on an uncooperative patient.

Composite Strip Crowns Technique

  • Select a primary celluloid crown form (Unitek Strip Crown, 3M, St. Paul, MN, Nowak Crowns, Nowak Dental Supplies Inc., Carriere, MS) with a mesio-distal incisal width equal to the tooth to be restored by placing the incisal edge of the crown against the incisal edge of the tooth.
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  • Remove decay with a medium to large round bur on a slow speed handpiece.
  • If pulp therapy is required do it at this time.
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  • Reduce the interproximal surfaces by 0.5 to 1.0mm.
  • The interproximal walls should be parallel and the gingival margin should have a feather edge.
  • Reduce the facial surface by 1mm and the lingual surface by 0.5mm.
  • Create a feather-edge gingival margin.
  • Round all line angles.


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  • Trim the selected crown by removing the collar and the gingival excess material with crown and bridge shears.
  • Place a small vent hole on the lingual surface with a bur or explorer to allow escape of trapped air when the composite filled crown is seated.


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  • Fit the crown on the prepared tooth.
  • The crown should extend 1mm below the gingival margin.
  • Maxillary lateral incisors are usually 0.5 to 1.0mm shorter than central incisors.


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  • Select the appropriate shade of composite (extra light).
  • Fill the crown with resin material approximately two thirds full.


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  • Etch the tooth with acid gel for 15 seconds, wash and dry the tooth, and apply bonding agent.
OR
  • Use a self-etching bonding agent.
  • Polymerize.


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  • Seat the filled crown form on the tooth.
  • Remove the excess material from the vent hole and the gingiva.
  • Repeat the procedure with the adjacent teeth.
  • Polymerize the material from both the facial and lingual directions.


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  • Remove the celluloid form by cutting the material on the lingual with either a composite finishing bur or scalpel.
  • Pry the celluloid form off the tooth.
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  • Very little finishing is required except for adjusting the occlusion and smoothing gingival margins.
  • Use flame shaped and rounded composite finishing burs for finishing.


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  • Repeat the procedure for adjacent teeth.
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