Talking with Patients

Cracked Tooth
Lee W. Boushell, DMD, MS*

WHAT IS IT? pulp’s response to the presence of in ongoing fracture propagation

the bacteria in the fracture. Crack deeper into the dentin with result-
The term “cracked tooth” is gener-
propagation may also extend into ant increased sensitivity. Some
ally used to describe the develop-
the root system of a tooth. cracked teeth are only painful
ment of a fracture that follows the
when chewing harder foods or
long axis of a tooth. Shallow
On occasion, sideways forces on chewing with the teeth in certain
cracks (generally referred to as
the tooth cause the vertical fracture positions. Frequently, fractures
“craze lines”) are limited to the
to propagate in a horizontal extend horizontally, and a portion
outside layer (enamel) of teeth.
fashion (Figure 1) and may eventu- of the tooth (a complete fracture)
Excessive biting forces may lead to
ally result in loss of part of the is obviously lost.
progression of a surface fracture
tooth (e.g., a complete cusp frac-
through the enamel and into the
ture). Loss of tooth structure from Dentists will use careful visual
sensitive part of the tooth called
dental decay frequently increases examination to identify the loca-
dentin. Fractures may grow in
tooth susceptibility to fracture for- tion of suspected incomplete frac-
depth and width, which allows
mation. Teeth that have therapeutic tures. Early fractures may require
staining by food molecules and
removal of diseased nerve tissue the use of a small light that is
invasion by bacteria of the oral
(“root canal treatment”) are at placed on the cheek side and
cavity. Fractures that initially do
greater risk for fracture of the tongue side of the tooth. The light
not result in loss of part of the
crown and/or the root of the tooth. passing into the tooth will abruptly
tooth are considered incomplete.
stop at the fracture, which enables
Incomplete fractures that are HOW IS IT DIAGNOSED visual detection. Long-standing
moving vertically further into the AND TREATED? fractures frequently are stained and
dentin or “propagating” may cause Your dentist may identify enamel easily seen. Incomplete fractures
pain during chewing or when the craze lines during routine examina- are rarely detected by standard
teeth are pressed firmly together tions. These craze lines do not radiographic analysis. The presence
(Figure 1). This sensitivity may cause sensitivity and do not require of bacteria in these fractures may
cease when propagation stops and any treatment. In addition to craze result in the development of decay
then return if the fracture begins to lines, cracked teeth that are not along the fracture. This decay may
extend deeper into the tooth struc- sensitive are commonly seen by be visually detected by changes in
ture. If the fracture progresses into dental health-care providers. In the color and transparency of the
the nerve center (“the pulp”) of the most cases, the initial development tooth adjacent to the fracture
tooth, then sensitivity during of these cracked teeth resulted in and/or by use of dental radio-
chewing may increase to a con- an immediate pain that rapidly dis- graphs. Selective pressure applied
tinual pain that will continue until sipated, leaving no further sensitiv- to individual cusps of a suspicious
the nerve dies or is removed. The ity for a period of time. Ongoing tooth is used to identify if a frac-
primary reason for the pain is the chewing pressures frequently result ture is active, its relative location,

*Assistant Professor, Department of Operative Dentistry,

University of North Carolina at Chapel Hill School of Dentistry, Chapel Hill, NC, USA

© 2009, COPYRIGHT THE AUTHOR

J O U R N A L C O M P I L AT I O N © 2 0 0 9 , W I L E Y P E R I O D I C A L S , I N C .
68 DOI 10.1111/j.1708-8240.2008.00233.x VOLUME 21, NUMBER 1, 2009
 TA L K I N G W I T H PAT I E N T S

procedure is the potential develop-

ment of a vertical fracture in the
root system. Fractures that extend
through the pulp and into the root
system of the tooth usually cannot
be reinforced, and the tooth
is extracted.

CONCLUSIONS
A “cracked tooth” has developed
a vertical fracture that has the
Figure 1. Teeth with incomplete vertical fractures (black potential to propagate over time.
arrows) and an incomplete horizontal fracture (white Increased fracture severity may
arrow) (courtesy of Dr. John Sturdevant, University of progressively lead to chewing
North Carolina–Chapel Hill).
sensitivity, tooth decay, loss of
part of a tooth, nerve (pulp)
and the region of the tooth that is involved the pulp of the tooth is problems, and, in extreme cases,
involved. Fractures that begin to reinforced with a restoration that tooth removal. Regular dental
extend onto the root surface may covers the biting surface, such as care and good communication
create an isolated gum defect an onlay or crown. The goals of between you and your dentist
that can be detected during a this procedure are to rigidly will allow early detection
dental evaluation. encircle the tooth structure that of fractures. Early intervention
contains the fracture, distribute increases the chances of successful
Your dentist has multiple means biting pressures over the whole reinforcement procedures. Frac-
of restoring lost portions of your tooth, and limit the potential for tures that involve the pulp will
tooth. These include fillings placed further propagation. require its removal. The nature of
directly in/on your tooth to create the tooth sensitivity and diagnos-
normal shape and function. A Fracture invasion into the pulp tic findings will help your dentist
more severe complete fracture necessitates its removal followed prescribe appropriate steps indi-
requires the use of an onlay or by reinforcement of the cracked cated to give your cracked tooth
crown. A sensitive tooth with an tooth as described above. An asso- the greatest chance of normal use
incomplete fracture that has not ciated risk of the pulp removal for a lifetime.

VOLUME 21, NUMBER 1, 2009 69