Strip crowns Flashcards
What are the indications for restoration of anterior teeth?
Carious lesions (multiple surfaces or involving incised edges)
Cervical decalcification / demineralization
Developmental defects of enamel
Following pulp therapy
High caries risk patients
What are some contra-indications of restoring anterior teeth?
Close to exfoliation
More than 1/3rd root resorbed
Irreversible pulpitis (would require pulpectomy and strip crown)
Inadequate tooth structure
What are the advantages of composite resin strip crowns?
Aesthetics
Easy to repair
What are the disadvantages of composite resin strip crowns?
Technique sensitive (Contamination with blood or saliva will result in poor bonding and discolouration of the crown)
Local anaesthetic is required
What are the features of the primary maxillary central incisor?
Wider mesio-distally than inciso-cerivally
No mamelons
Cingulum and marginal ridges more prominant than on the permanent successor
Lingual fossa is deeper
How is the maxillary lateral incisor different to the maxillary central incisor?
Crown is similar to that of the central incisor but much smaller in all dimensions.
Incisal angles are more rounded than on the central incisor
What does the primary mandibular central incisor look like?
Resembles primary mandibular lateral incisor more than its permanent central incisor
Extremely symmetric
Not as constricted at the CEJ as the primary maxillary incisor
Lingual surface appears to be smooth
Tapers towards prominent cingulum.
How does the primary lateral mandibular incisor differ from the primary central mandibular incisor?
Similar in form to the mandibular central incisor but wider and longer
Incisal edge slopes distally
Disto-incisal angle is more rounded
How does the primary maxillary canine differ from the permanent maxillary canine?
Relatively longer crown and sharper cusp than its permanent successor when first erupted
Mesial and distal outlines are rounder
What are the features of the primary mandibular canine?
Resembles the primary maxillary canine with some differing dimensions
Tooth is much smaller labiolingually
Distal cusp slope is longer than mesial cusp slope
Lingual surface is marked by a shallow lingual fossa
How is a strip crown prepared?
Caries are removed
Incisal edge is reduced (~1.5mm)
Inter proximal reduction (parallel to interproximal walls and 0.5 to 1mm)
Facial reduction 1mm
Lingual reduction is 0.5mm if there is a deep overbite
Knife edge gingival margin (round off all line angles)
How are strip crowns placed onto the preparation?
Strip crown is selected (Proper mesiodistal width comparable to the tooth to be restored)
Strip crown form trimming using curved scissors
Trial fittign the crown below the gingival crest comparing crown height with adjacent teeth.
Use GIC lining if necessary. Acid etch the tooth, dentine bonding application and light cure.
Fill the crown form with composite resin.
Seat the crown firmly onto the tooth
Remove excess resin material
Light cure the composite crown
Remove the strip crown using an excavator or probe and insert instrument beneath the edge of the celluloid strip to strip off the crown form.
Check occlusion
Polishing
Clinical tips for strip crowns:
Restore all 4 incisors at the same time
Restore 2 central incisors on one visit then the laterals at the next
If more than one incisor is restored the crowns should be seated together.
