This study aimed to determine if there is a correlation between bone quality in the mandibular condyle and articular eminence and temporomandibular joint hypermobility. The study retrospectively analyzed 58 patients with TMD using CBCT images. Bone quality was assessed and patients were classified as having or not having TMJ hypermobility. The results found no statistically significant difference in bone quality between the two groups, indicating no direct relationship between bone quality and TMJ hypermobility in TMD patients.

1. IS THERE ANY CORRELATION BETWEEN BONE
QUALITY AND MANDIBULAR HYPERMOBILITY IN
THE TEMPOROMANDIBULAR JOINT
DYSFUNCTION ?
Dr. Ibrahim Sevki Bayrakdar 1, Dr. Binali Cakur 2
1. Eskisehir Osmangazi University Faculty of Dentistry
Department of Oral and Maxillofacial Radiology, Eskisehir / Turkey
2. Ataturk University Faculty of Dentistry
Department of Oral and Maxillofacial Radiology, Erzurum / Turkey

2. "Joint hypermobility" is generally used to
indicate an excessively increased range of
motion of a joint and is classified into single-
joint or generalized sub-types. The etiology of
hypermobility is unclear. Joint hypermobility is
found more frequently in people with general
joint laxity (GJH). Therefore, in the literature
many studies concerning joint hypermobility
are related to GJH.

3. In addition, as regards the joint hypermobility, although
some studies reported that there was a linear or inverse
relationship between the joint hypermobility and bone
mineral density in postmenopausal women. Although in
the literature there are a few studies about the
relationship between the joint hypermobility and bone
mineral density, there is no study concerning TMJ
hypermobility related to bone quality in the TMD.

4. The objective of the present study was to
determine whether there was a
correlation between the bone quality of
the mandibular condyle and articular
eminence and temporomandibular joint
hypermobility (subluxation) in
temporomandibular joint dysfunction.

5. MATERIALS AND METHODS
 The study was approved by the ethics board of the Faculty of Dentistry,
Ataturk University (Protocol no 06/2016) and all participants signed an
informed consent agreement.
 This retrospective study was performed using tomographic images
obtained from patients with TMD with or without the
temporomandibular joint hypermobility (subluxation) who underwent
CBCT.
 Patients were examined for the presence of anamnesis and diagnosed
according to the Research Diagnostic Criteria for TMD.

6.  Study participants were classified as having TMD with (normal)
or without the temporomandibular joint hypermobility
(subluxation).
 In total, 58 patients (29-the patient with the
temporomandibular joint hypermobility and 29-the patient
without the temporomandibular joint hypermobility) with TMD
were analysed retrospectively with CBCT.
 The age range was 15 to 67 years old, with a median age of
30.2 ± 12.7
 Of the fifty-eight patients, 41 (70.7 %) were female and 17 (29.3
%) were male.

7.  The CBCT images of the TMJ were evaluated with regard to the
temporomandibular joint hypermobility and both the bone quality of
the mandibular condyle and articular eminence. The following
evaluations of the mandibular condyle and articular eminence were
made of parasagittal images obtained from axial plane:

9. 1) Temporomandibular joint hypermobility: Assessment of the condylar
position relative to the articular eminence assessed on CBCT maximal mouth
opening. In this position, the condyles found translating anterior to articular
eminence on CBCT images was taken from maximal mouth opening.

10. 2) Bone Quality Index (BQI): The bone
quality based on the amount and
proportion of the cortical and trabecular
bone.The four types are:
I. Homogenous cortical bone (A)
II. Thick cortical bone with a marrow cavity
(B)
III. Thin cortical bone with dense trabecular
bone of good strength (C)
IV. Very thin cortical bone with low-density
trabecular bone of poor strength. (D)

11. Statistical Analysis
 Statistical analysis was performed using SPSS software for
Microsoft Windows (SPSS, version 20, Chicago, IL, USA).
 Correlations among the variables (bone quality index, the
temporomandibular joint hypermobility, normal motion) were
established using Spearman’s correlation coefficient with the
significance set at p < 0.05
 Kappa statistics for agreement was used to assess the intra-
observer reliability. Kappa statistics were interpreted as <0 = poor
agreement, 0.00–0.20= slight agreement, 0.21–0.40 = fair
agreement, 0.41–0.60 = moderate agreement, 0.61–0.80 =
substantial agreement, 0.81–0.99 = almost perfect agreement, and
1.00 = perfect agreement.

12. RESULTS

13.  No statistically significant difference was found between the patient
with or without the temporomandibular joint hypermobility and the
BQI of the articular eminence and condyle (p>0.05). In other words,
there was no direct linear relationship among these variables.
 The intra-observer coefficient values showed high reliability for the
temporomandibular joint hypermobility or normal motion and BQI.
The intra-observer coefficient was 0.94 (almost perfect agreement)
for the temporomandibular joint hypermobility or normal motion
and 0.89 (almost perfect agreement) for the BQI.

14.  Because to the best of our knowledge in the literature there are
no study about the relationship between the
temporomandibular joint hypermobility and the bone quality,
this is the first study evaluating whether or not a relation exists
between the temporomandibular joint hypermobility and the
bone quality.

15. LIMITATIONS
 The small sample consisted of patients who sought treatment
for TMD. As a result, the study group might not accurately
represent the general population.
 The study participants were not evaluated for the benign joint
hypermobility syndrome.
 Radiologic interpretation of the bone quality is challenging.

16. There was no direct linear relationship between the bone
quality of the mandibular condyle and articular eminence
and the temporomandibular joint hypermobility in
temporomandibular joint dysfunction. The bone quality
types did not have a direct influence on the
temporomandibular joint hypermobility in the joint in TMD.
CONCLUSION

17. THANK YOU FOR YOUR ATTENTION…