Journal of Experimental and Integrative Medicine
Original Article
www.jeim.org
DOI: 10.5455/jeim.270415.or.128
Stafne bone cavity: A retrospective
panoramic evaluation on prevalence in
Turkish subpopulation
Hakan Avsever1, Hakan Kurt2, Tolga Berkay Suer3,
Hatice Seda Ozgedik1
1
Department of
Dentomaxillofacial
Radiology, Dentistry
Center, Gulhane Military
Medical Academy, Ankara,
Turkey, 2Department
of Dentomaxillofacial
Radiology, Faculty
of Dentistry, Ankara
University, Ankara,
Turkey, 3Department of
Dentomaxillofacial Surgery,
Haydarpasa Military
Hospital, Istanbul, Turkey
Address for correspondence:
Hakan Kurt,
Department of
Dentomaxillofacial Radiology,
Ankara, Turkey.
E-mail: mhakankurt@yahoo.
com
Received: April 01, 2015
Accepted: April 27, 2015
Published: September 20, 2015
ABSTRACT
Objective: Stafne’s bone cavity was first described by Stafne, who reported 35 cases of unilateral,
asymptomatic radiolucencies in 1942. The bone cavities are located on the posterior mandible and below the
mandibular canal, above the mandibular base. They usually include an ectopic salivary gland and their incidence
was reported as between 0.1% and 0.48%. The aim of this study is to investigate the frequency of Stafne bone
cavity (SBC) in a Turkish subpopulation. Materials and Methods: A retrospective, observational study was
designed with panoramic radiographies. A total of 14,250 panoramic radiographies were inspected. 192 of
panoramic radiographs were considered as unfit for the study due to various reasons (e.g., low image quality
and big artefact) and were excluded from the study. The localizations of the defects on the mandible were
noted. Results: Among the 14,058 patients, only 13 (0.09%) had SBC, of whom 4 were female (30.7%),
and 9 were male (69.3%). The age range of patients with SBC was 21-75 years (mean age: 49.2). All the
cavities were detected in the posterior region of the mandible. Conclusion: SBC is a rare developmental
anomaly and has a typical radiologic appearance. Panoramic radiography seems to be a sufficient diagnostic
tool for detecting SBC.
KEY WORDS: Bone defects, panoramic radiography, salivary gland, Stafne bone cavity
INTRODUCTION
Edward Stafne, who reported 35 radiolucent lesions in the
mandibular angle, noticed utilizing intraoral dental films, first
discovered Stafne bone cavity (SBC) in 1942. The bone cavities
were located lingually on the posterior mandible and below the
mandibular canal, above the mandibular base [1]. Since then many
different terms have been used to describe this entity including;
static bone cyst, lingual mandibular bone defect, SBC, idiopathic
bone cavity, or lingual mandibular bone depression [2-4]. Although
the “cyst” term has traditionally been used to identify this lesion,
fluid content in the cavity has never been reported. They usually
include an ectopic salivary gland [1,5]. Although the posterior
lingual type has an incidence between 0.1% and 0.48%, some
cadaver studies show that the incidence could be as high as
6.06% [2,4]. Usually, 50-70 years old males are affected [2,6].
The anterior variant was reported first by Richard and
Ziskind [7] in 1957 as a lingual bone concavity in the
J Exp Integr Med ● 2015 ● Vol 5 ● Issue 2
anterior region of the mandible. Since then, only few cases
have been reported in the literature [8]. The frequency of
the anterior type of SBCs are seen seven times less than
posterior type and usually located between the incisor and
the premolar areas, above the insertion of the mylohyoid
muscle [2,9]. Although posterior type of SBCs can usually
be diagnosed clearly on panoramic radiographs because
of their unique location, anterior bone defects may be
misdiagnosed or misleaded with several different pathologic
entities of the jaw such as traumatic bone cyst, periapical
cyst, keratocyst, non-ossifying fibroma, ameloblastoma, or
focal osteoporotic bone marrow defect. In these situations,
therefore, further confirmatory testing is warranted for
differential diagnosis [10].
The aim of this study is to describe the radiological characteristics
of SBC and to reveal its frequency in Turkish subpopulation for
the purpose of avoiding misdiagnosis.
89
Avsever, et al.: The prevalence of Stafne’s bone cavity
MATERIALS AND METHODS
This is a retrospective study of panoramic radiographs collected
from patients’ files that consisted of patients who applied to the
Department of Dentomaxillofacial Radiology, Gulhane Military
Medical Academy, Ankara, Turkey, between years of 2010 and
2014. A total of 14,250 panoramic radiographies were evaluated,
and 192 images were excluded due to poor image quality and
technical reasons. As a result, 14,058 panoramic radiographies
were included in this study.
All panoramic radiographs were taken by Kodak 8000C Digital
Panoramic System at setting of 78 kV and 12 mA exposure.
Two dentomaxillofacial radiologists, who had minimum
7 years of experience, examined all images. Kodak Dental
Imaging Software Viewer (version 6.12.10.0) was used for image
evaluation on a standard personal computer with calibrated
monitor (HP Compaq LE1711 LCD Monitor, Palo Alto, CA,
USA). The level of contrast and brightness of the images was
left to examiners’ choices.
Inclusion criteria were: Round or ovoid radiolucency in the
mandible; homogeneous appearance; sharp cortical demarcation
with a clear distinction from anatomical structures [Figure 1].
Exclusion criteria were: Panoramic radiographs with poor
diagnostic quality, distortions or big artefacts. The age and sex
were recorded for all patients and for the cases of SBC, age,
sex, side, and location of the lesions were noted as well. The
complaints as pain, swelling, paresthesia or tooth migration,
and radiologic appearance of the patients who have Stafne bone
defect were also recorded after 1-year follow-up. All statistical
analyzes were performed using SPSS software (version 15.0;
SPSS Inc., Chicago, IL, USA).
RESULTS
A total of 14,058 images met the inclusion criteria and
were examined. Of these 7,009 (49.86%) were male and
7,049 (50.14%) were females. The age and sex distribution of
the study population are presented in Table 1.
13 (0.09%) of the 14,058 individuals had SBCs, of whom
4 (0.02%) were female and 9 (0.06%) were male. All of them
were found on the mandibular posterior site. The bilateral
presentation was not seen. Of the 13 unilateral cases, 9 (69.2%)
were on the left, and 4 (30.8%) were on the right side. The
frequency of SBC was found higher in individuals aged over
40 years. The ages of the patients with SBC ranged from
21 to 75 years (mean age 49.23 years). Stafne prevalence of the
right side was found to be 0.06%, whereas left side’s prevalence
was calculated as 0.02%. The distribution of gender, age and
localization is seen in Table 2. There were no pathological
changes after 1 year clinical and radiologic follow-up.
DISCUSSION
Since its first description by Stafne, many terms have been
coined to describe asymptomatic radiolucencies at the angle
of the mandible [2-4,11-13]. The bone cavity is usually found
incidentally during routine radiologic evaluation, most often
appearing as radiolucent, unilateral, ovoid defect near the angle
area below the inferior alveolar canal. Even though it is mostly
seen in the posterior of mandible near the angle, rarely it has
been found in an anterior portion of the mandible. When it
is seen in the anterior mandible region, distribution of bone
cavities’ locations are as follows; 65% between the cuspid and the
first molar, and 24% incisor area. SBCs are most often unilateral
defects however less frequently bilateral defects are seen. To
the best of our knowledge, bilateral anterior bone defects were
reported only 9 times in literature [14-22].
According to literature, SBCs are diagnosed commonly in men
and aged between 50 and 70 years [2,6,23]. Men represent most
cases with a ratio of 3:1, but Philipsen et al. [2] reported a ratio
of 6:1. In this study, there was 9:4 of ratio on behalf of men.
Although its prevalence in the published series ranges from
0.08% to 0.5%, prevalence in some cadaver reports is relative
high (1.3-6.6%) [2]. The limitations of two-dimensional imaging
modalities in the aforementioned series could be the reason
for this lower rates of prevalence when compared to cadaver
studies [2]. Anterior Stafne prevalence was found to be 0.003%,
whereas posterior Stafne prevalence was 0.081% according
to Sisman et al. [23]. In this study, the authors found 0.09%
Table 1: The age and sex distribution of the study population
n (%)
Age
range
Female
Male
Total
0-20
20-40
40-50
≥50
Total
414 (2.94)
2,262 (16.09)
1,119 (7.95)
3,254 (23.14)
7,049 (50.14)
482 (3.42)
2,165 (15.4)
1,052 (7.48)
3,310 (23.54)
7,009 (49.86)
896 (6.37)
4,427 (31.49)
2,171 (15.44)
6,564 (46.69)
14,058 (100)
Table 2: The distribution of gender, age, and location of the
patients with stafne bone cavity
Figure 1: The panoramic appearances of the ovoid Stafne bone defects
90
Age
range
Female
Right
Male
Female
Left
Male
Total
0-20
20-40
40-50
≥50
0
1
0
1
0
2
1
3
0
0
1
0
0
2
0
2
0
5
2
6
J Exp Integr Med ● 2015 ● Vol 5 ● Issue 2
Avsever, et al.: The prevalence of Stafne’s bone cavity
prevalence rate for the occurrence of the SBC, and this result
is compatible with previous reports.
Due to their asymptomatic nature, most of the cases are
incidentally discovered in the routine radiographic evaluation.
However, there are a few reports which have been represented
with pain in the region of SBC [24,25]. Turkoglu and Orhan [8]
reported a case presented with pain located in anterior mandible,
but they also emphasized that the pain was related to the
deep caries lesion in the neighboring tooth. In this presented
retrospective analysis, none of the patients had any complaints
such as pain, swelling, or infection, etc. All of the cases in this
report were incidental discoveries on a routine panoramic
radiographic evaluation.
Even though numerous theories have been attempted to
explain the etiology of the SBC, its etiology still remains
controversial. Stafne [1] suggested that defects were
developmental and occurred congenitally due to hypoplasia
of the mandible. The youngest patient who had been reported
in the literature was 11-year-old [26]. This theory was not
accepted by some authors because it does not explain why the
lesions do not occur in childhood. In the present study, we have
detected the ages of patients with SBC as 21 years and above.
Another theory mentions the pressure of salivary gland to the
lingual cortex of the mandible. The local pressure of salivary
glands to the mandible delays development. According to this
theory, the submandibular gland is related with the posterior
defects while the sublingual gland is related with the anterior
defects [2-4].
Minowa et al. [12,13] claimed that acquired vascular lesions
may be the one of the possible causes of bone depression. They
have also been reported that the facial artery and its branches
can become tortuous owing to hypertension as an explanation.
And they noted that the incidence of hypertension increases
with age and also increases the incidence of SBC. In our
retrospective study, only 2 patients had hypertension in their
records. However, there was no way to know whether or not
hypertension caused SBC or defect was caused by some other
reason. According to our point of view, further studies should
be done to clarify the question marks about this topic.
Because of the SBC is thought to be a normal anatomical variant
rather than a pathological condition, surgical procedures are
not necessary for the treatment neither for anterior nor for a
posterior variant. In general, the management of SBC should
be a conservative approach by radiological follow-up. Surgical
procedures or biopsy should be performed only in atypical cases
or suspected lesions. Only if remarkable changes were seen on
routine radiographic follow-up shows then surgical intervention
could be applied [2,11]. In the present study, after 1-year clinical
and radiologic follow-up, there were no pathological changes.
Especially, anterior variant of SBC mimics odontogenic
pathology. The posterior variant of SBC has relatively specific
appearance. The differential diagnosis of SBC should be done
with several pathologies such as odontogenic cystic lesions,
fibrous dysplasia, vascular malformations, ameloblastoma,
J Exp Integr Med ● 2015 ● Vol 5 ● Issue 2
giant cell granuloma, odontogenic keratocyst, aneurysmal bone
cyst, eosinophilic granuloma, benign salivary gland tumors,
neurogenic tumors, myxoma, multiple myeloma, and metastatic
diseases [2,8,10,23,27].
In most cases, diagnosis of SBC is easier because of its specific
characteristic appearance on radiography. They are usually
diagnosed on conventional plain films such as intraoral
dental radiographs, plain films of head and neck region and
orthopantomographs. These imaging modalities are often
obtaining sufficient information for diagnosis. However when
the lesions are atypical, then the advanced diagnostic imaging
modalities such as computed tomography (CT), cone-beam
CT (CBCT), magnetic resonance imaging (MRI), and
sialography are required for differential diagnosis. Although
CT has some disadvantages such as high radiation exposure
and possible allergic reaction against contrast ingredients,
CT evaluation is useful for identifying soft tissue. Most CT
evaluations of SBC have shown salivary tissue, fat and soft
tissue [3,4].
Some authors also advocate that CT should be supported by the
other imaging methods such as MRI [27] and sialography [8].
Because of some limitations and disadvantages of CT, MRI
is suggested as the primary diagnostic method for SBC. MR
imaging provides adequate information about SBC even
without any intravenous contrast material and exposing the
patient to radiation. Its major disadvantages are the high cost
and the field distortion artifacts from dental materials; however,
it has been recommended by many authors [27]. Sialography is
also suggested as a diagnostic method, but it is also mentioned as
an uncomfortable procedure and highly difficult to be tolerated
by the patient. It obtains positive results only if glandular tissue
exists in the cavity, but there are case reports of surgically proven
SBC with negative sialogram results. Sialography exposes
the patient to ionizing radiation and also can be difficult to
perform [28]. Thus, it has been rarely used to diagnose SBC.
In the last decade, it has been created a major revolution on
imaging technology with the development of CBCT by which
the dentomaxillofacial imaging can be performed with less
radiation exposure [29]. One of the most precious advantages
of CBCT is that the level of resolution was relatively higher
than medical CT. In recent years, CBCT is recommended
as an alternative diagnostic modality to medical CT in the
maxillofacial region [30]. We believe that the diagnosis of SBC
can be confirmed with the CBCT as an alternative to medical
grade CT.
CONCLUSION
The diagnosis of SBC could be easily made by a practitioner
due to its asymptomatic nature and specific appearance on
routine plain radiographs. Improve of practitioners’ knowledge
about this lesion will prevent the potential misdiagnosis of the
defect. Only atypical or suspicious lesions should be evaluated
with advanced non-invasive radiological techniques such as CT
or magnetic resonance studies. As a result, it will be possible to
avoid unnecessary invasive surgical procedures.
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Avsever, et al.: The prevalence of Stafne’s bone cavity
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© AKAY. This is an open access article licensed under the terms of
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Source of Support: Nil, Conflict of Interest: None declared.
J Exp Integr Med ● 2015 ● Vol 5 ● Issue 2