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.
With a cooperative patient, the time required for placement is comparable to that of a stainless steel crown or polycarbonate crown.
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 crown or polycarbonate crown 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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Reduce the interproximal surfaces by 0.5 to 1.0 mm. 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 1.0 mm shorter than central incisors.
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OR
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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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