for the distal fragment to become opaque or require further restorative intervention in
the form of a veneer or full coverage crown (693HFig. 12.18). If the fracture line through
dentine is not very close to the pulp then the fragment may be reattached immediately.
If, however, it runs close to the pulp then it is advisable to place a suitably protected
calcium hydroxide dressing over the exposed dentine for at least 1 month while
storing the fragment in saline, which should be renewed weekly.
Technique
- Check the fit of the fragment and the vitality of the tooth.
- Clean fragment and tooth with pumice-water slurry.
- Isolate the tooth with rubber dam.
- Attach fragment to a piece of sticky wax to facilitate handling.
- Etch enamel for 30 s on both fracture surfaces and extend for 2 mm from fracture
line on tooth and fragment. Wash for 15 s and dry for 15 s. - Apply bonding agent +/- dentine primer according to manufacturer's instructions
and light cure for 10 s. - Place appropriate shade of composite resin over both surfaces and position
fragment. Remove gross excess and cure 60 s labially and palatally. - Remove any excess composite resin with sandpaper discs.
- Remove a 1-mm gutter of enamel on each side of fracture line both labially and
palatally to a depth of 0.5 mm using a small round or pear-shaped bur. The finishing
line should be irregular in outline. - Etch the newly prepared enamel, wash, dry, apply composite, cure, and finish.
Enamel-dentine-pulp (complicated) crown fracture
The most important function of the pulp is to lay down dentine which forms the basic
structure of teeth, defines their general morphology, and provides them with
mechanical strength and toughness. Dentine deposition commences many years
before permanent tooth eruption and when a tooth erupts the pulp within still has
work to do in completing root development. Newly erupted teeth have short roots,
their apices are wide and often diverging, and the dentine walls of the entire tooth are
thin and relatively weak (694HFig. 12.19 (a)). Provided the pulp remains healthy, dentine
deposition and normal root development will continue for 2-3 years after eruption in
permanent teeth (695HFig. 12.19 (b)). Loss of pulp vitality before a tooth has reached
maturity may leave the tooth vulnerable to fracture, and with an unfavourable crown-
root ratio. In addition endodontic treatment of non-vital, immature teeth can also
present technical difficulties which may compromise the long-term prognosis of the
tooth.