|Year : 2020 | Volume
| Issue : 3 | Page : 222-228
Evaluation of condyle- fossa position and articular eminence angulation in dentate and edentate patients – A cephalometric pilot study
Pradhuman Verma1, Princy Mahajan1, Samar Ali Faraz2, Konkati Srikanth3, B Ravichandra4, Natasha Bathla5
1 Department of Oral Medicine and Radiology, Surendera Dental College and Research Institute, Sriganganagar, Rajasthan, India
2 Consultant Oral Physician, Patna, Bihar, India
3 Consultant Orthodontist, Panineeya Mahavidyalaya Institute of Dental Sciences and Research Center, Hyderabad, India
4 Department of Orthodontics, Panineeya Mahavidyalaya Institute of Dental Sciences and Research Center, Hyderabad, India
5 Department of Prosthodontics, Himachal Dental College, Sundernagar, Himachal Pradesh, India
|Date of Submission||24-Apr-2020|
|Date of Decision||29-May-2020|
|Date of Acceptance||01-Jul-2020|
|Date of Web Publication||29-Sep-2020|
Dr. Pradhuman Verma
Department of Oral Medicine & Radiology, Surendera Dental College & Research Institute, H.H Gardens, Power House Road, Srigangangar - 335 001, Rajasthan
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Temporomandibular joint is a mobile synovial joint where articulated bones are separated by a joint cavity. Its functional harmony is disrupted by a long standing period of edentulousness which could be analyzed using lateral Cephalograph. Aim and Objectives: To evaluate the condyle–fossa position and articular eminence angulation in dentate and edentate patients using a lateral cephalogram along a different axis. Materials and Methods: Cross-sectional study consisted of randomly selected 40 patients with 20 dentulous patients (Group I), and age- matched 20 completely edentulous patients (Group II), within an age group 45–65 years. Lateral cephalograms were performed for all selected patients using single Kodak 8000C digital OPG/Ceph machine, (Rochester, New York, United States). All the radiographs were digitally traced and evaluated twice for condyle- fossa position along X and Y axis and articular eminence angulation by an Oral & maxillofacial radiologist at an interval of two days. The collected data was tabulated and analyzed using SPSS Software version 20 using unpaired t-test and tests of normality. Results: Significant difference in condyle - fossa distances along the X and Y axis in two study groups was suggestive of more upwards and forwardly placed condyles and more anteriorly placed glenoid fossae in Group II patients. Also, articular eminence angulation was noted more in edentulous patients but the difference was statistically insignificant. Conclusion: A great variation in condylar–fossa position was observed in the edentulous patient when compared to the dentulous patient due to remodeling or degenerative changes that occur during the period of edentulousness.
Keywords: Edentulousness, harmony, lateral cephalograph, synovial joint
|How to cite this article:|
Verma P, Mahajan P, Faraz SA, Srikanth K, Ravichandra B, Bathla N. Evaluation of condyle- fossa position and articular eminence angulation in dentate and edentate patients – A cephalometric pilot study. J Indian Acad Oral Med Radiol 2020;32:222-8
|How to cite this URL:|
Verma P, Mahajan P, Faraz SA, Srikanth K, Ravichandra B, Bathla N. Evaluation of condyle- fossa position and articular eminence angulation in dentate and edentate patients – A cephalometric pilot study. J Indian Acad Oral Med Radiol [serial online] 2020 [cited 2020 Dec 3];32:222-8. Available from: https://www.jiaomr.in/text.asp?2020/32/3/222/296592
| Introduction|| |
Temporomandibular joint (TMJ) components represent a three–dimensional position relationship between condyle, glenoid fossa, and articular eminence. It is an articular triad with two points of contact provided by TMJ and third contact by the dentition. The TMJ is formed by mandibular condyle fitting into the mandibular fossa of temporal bone which is separated by third non-ossified bone that is the articular disc. It is a known fact that skeletal components have the potential to undergo remodeling throughout life, which is a significant view point to generate direct relationship between a patient who is dentulous and edentulous.
The loss of teeth, abrasion, unstable denture bases and occlusion are certain pathologies that would trigger an occlusal disharmony leading to skeletal and functional changes in TMJ. With the loss of teeth, the adaptive mechanisms become active to compensate for disharmony but if adaptive capability of the joint exceeded, it results in degenerative joint disease. If these changes occur, the morphology of the disc can be irreversibly altered producing biomechanical changes during function followed by alteration in the morphology of glenoid fossa that varies with change in the pattern of dentition. The temporal part of TMJ is greatly under the influence of remodeling/degenerative changes throughout life. The lateral cephalogram is the radiographic modality chosen to view the condyle–fossa relationship in dentulous and edentulous patients as it is a routine procedure to be performed in dental offices and institute. It is easy to perform and known to be an easily reproducible imaging technique for determining the growth changes of individuals. With this background, this study was conducted with the purpose to evaluate the condyle–fossa position and articular eminence inclination in dentate and edentate patients using a lateral cephalogram along a different axis.
Clinical significance of the study: The TMJ represents a three-point articulating system, two points of contacts between condyle -fossa and third contact being dentition. Alteration in any one component of this articulating system will produce secondary morphological changes in the other two contact points. After the loss of full dentition in one or both jaws, the intercuspation and the retruded contact position disappear. Due to this, when both residual ridges approximate during the closure of jaws, the condyle–fossa position in the mandibular fossa may change. This pathological change in the condylar position is referred to as the edentulous position of the TMJ.
| Materials and Methods|| |
The pilot study comprised of randomly selected forty patients (n = 40), both male and female who visited the daily outpatient department of Oral Medicine and Radiology from July 2019 to January 2020. The patients were equally divided into two groups Group I (n = 20): dentulous patients and Group II (n = 20): completely edentulous patients with an age group ranging from 45 to 65 years. The informed written consent was obtained from all the patients before their enrollment in the study. The inclusion criteria of the study consisted of:
- Group I, patients with a full complement of teeth irrespective of third molars.
- Group II patients, with complete edentulousness duration of 1–5 years that is they are not wearing their complete dentures for the above-mentioned period.
- Asymptomatic patients.
- Lateral cephalograms of patients without TMJ bony pathologies.
- Radiographs of patients free of positional errors and image deformities.
The exclusion criteria consisted of:
- Pregnant female.
- Patients with a recent history of maxilla-facial trauma, inter-maxillary fixation, or post-surgical cases.
- Patients who were not able to communicate due to age or disease and patients who are not willing for radiographic investigation.
- Terminally ill or unconscious patients.
- Syndromic and medically compromised patients.
- Patients with endocrinal and medical disorders affecting the development of the maxillofacial complex.
- Rheumatoid arthritis, Osteoarthritis, Septic arthritis patients.
All patients were clinically evaluated by making them seated comfortably on a dental chair. The diluted 0.2% chlorhexidine gluconate mouthwash was given to rinse the oral cavity. An individual's demographic data, general and medical history, and clinical examination were carried out systematically. The examination was conducted to rule out any TMJ disorders for the selected subjects. The patients fulfilling the inclusion criteria were then subjected to digital lateral Cephalometric examination using Kodak 8000C digital OPG/Cephalometric machine (Rochester, New York, United States) following the ICRP guidelines. To standardize the procedure, all radiographs were taken by one trained radiographer. A tube potential of 82 kV, a tube current of 10 mA, and an exposure time of 500 ms were used to optimize the contrast of the digital images. The digital radiographs were processed and viewed by using Kodak dental imaging software, version 188.8.131.52 (Carestream Health Inc., Rochester, NY, USA). In Group II patients, lateral cephalograms were taken for the determination of freeway space or to determine correct occlusal vertical dimensions for prosthodontic procedures. All patients were positioned in the Cephalostat in natural head position. [Figure 1]. The Frankfort horizontal plane was standardized by a forehead positioner located at nasion. All the patients were instructed to bite in maximum intercuspation while remaining still throughout the exposure time. In Group II patients, lateral cephalograms were taken with complete dentures, which were fabricated after the screening test for TMJ disorder. All lateral cephalogram obtained were analyzed for skeletal Class I relationship of maxilla and mandible by Steiner's analysis. Then all the under mentioned linear and angular measurements were done on selected radiographs twice at an interval of two days by an Oral and maxillofacial radiologist independently using Kodak dental imaging software, version 184.108.40.206.
Following landmarks and planes used in performing the study are as follows,[Figure 2]:
- Frankfort horizontal plane (orbitale–tragion horizontal line)
- S- N plane (Sella–nasion)
- Nasion perpendicular (the vertical line drawn perpendicular to the F-H plane and extended inferiorly from nasion to form N- perpendicular).
Reference line: A line drawn parallel to the F- H plane and tangent to the most superior aspect of glenoid fossa marked as A-P [Figure 2].
Line 1: Line was drawn parallel to the reference line and tangent to the highest point of the condyle. Line 2: Line was drawn perpendicular to line 1 and tangent to the most anterior aspect of condyle. Line 3: Line was drawn parallel to line 2 and tangent to the most posterior aspect of condyle. Line 4: Line is drawn parallel to line 1, which is at a distance to Line 1 equal to that between line 2 and line 3. The center of the condyle was located by joining above four lines forming a square as suggested by Brewka, Hatjigiorgis, and Hongchen[Figure 3].
|Figure 3: Schematic representation of center of condyle & center of glenoid fossa location|
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Constructed planes used for the location of the center of glenoid fossa,,:
A line E-F was drawn parallel to the reference line and tangent to the crest of the articular eminence. X-axis: A line was drawn midway between and parallel to line E-F and reference line. Y-axis: A line was drawn perpendicular to the reference line at the point where the reference line intersected the height of fossa. The point of intersection of the X-axis and Y-axis indicated the center of the glenoid fossa.
The distance from the center of the condyle to the center of the glenoid fossa on the X-axis, and the Y-axis was measured and recorded.
Now a vertical line (N-perpendicular) was drawn perpendicular to the Frankfort horizontal plane and extended inferiorly from nasion. From the center of condyle and center of glenoid fossa horizontal lines were drawn perpendicular to N-perpendicular to determine the position of condyle position and glenoid fossa in dentulous and edentulous patients and the measurements obtained were compared [Figure 4].
|Figure 4: Constructed planes used in the study for location of center of condyle & center of glenoid fossa (a) Dentulous Patients (b) Edentulous patients|
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The articular eminence angle was recorded as the angle formed between the reference line (AP) and the line connecting the roof of condylar fossa with the highest point of eminence.
Statistical analysis used
The values obtained were tabulated and subjected to statistical evaluation using SPSS 20 software (SPSS Inc., Chicago). The intra-observer bias was calculated for all linear and angular measurements using the Wilcoxon signed- rank test. The mean values (in mm) were calculated on both the X and Y axis between Condyle- fossa for both the study groups and a t-test was done to assess the level of significance. The P < 0.05- significant, P < 0.005 - highly significant, P > 0.05 - non-significant were considered. Similarly, the mean distances between the center of condyle—N- perpendicular and the Centre of glenoid fossa—N- perpendicular were calculated and the significance level was assessed by using paired t-test. Then Kolmogorav-Smirnov & Shapiro- Wilks test of normality was done to check all the variables for the null hypothesis.
| Results|| |
The gender distribution of the total sample of randomly selected 20 dentulous and 20 edentulous patients were depicted in [Table 1]. The mean age of dentulous patients was 24.9±1.12 years years while for edentulous patients it was found to be 59.1±2.79 years. The intra-observer bias was found insignificant (p > 0.05), thus the first day obtained measurements were considered for further analysis. [Table 2] showed a comparison of mean distance on the Y-axis between the center of the condyle and center of the glenoid fossa in two study groups. The mean value was found to be 6.8 ± 0.768 mm in Group I patients while it was noted less in Group II patients i.e., 3.15±0.671 mm. The results obtained indicate that the condyles are positioned significantly (p < 0.01) more upwards in edentulous patients.
|Table 2: Distance on Y- axis between Condyle- fossa in Group I and Group II patients|
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[Table 3] showed a comparison of mean distance on the X-axis between the center of condyle and center of glenoid fossa in both the study groups and it was found that Group I patients showed a mean distance of 1.65±0.587 mm, whereas in Group II patients it was 4.0 ± 1.12 mm. The result showed that the condyles are positioned significantly (p < 0.01) more forwardly in edentulous patients.
|Table 3: Distance on X- axis between Condyle- fossa in Group I and Group II patients|
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[Table 4] showed a comparison of the mean distance between N-perpendicular and center of the condyle in both the study groups with their respective standard deviations. In Group I patients, the mean distance between N- perpendicular and the center of the condyle was found to be 84.35 ±1.31 mm in Group I patients while it was noted 69.9 ±1.77 mm in Group II patients. The results obtained indicate that the condyles are placed significantly (p < 0.01) more forward in edentulous patients.
|Table 4: Distance between center of Condyle - Nasion perpendicular in Group I and Group II patients|
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[Table 5] showed a comparison of the mean distance between N-perpendicular and center of glenoid fossa in both study groups. The results showed the mean distance was noted 82.75±1.25 mm in Group I patients while it was 72±2.13 mm in Group II patients, indicating the significantly (p < 0.01) more anteriorly placed glenoid fossae in edentulous patients.
|Table 5: Distance between Centre of glenoid fossa -Nasion perpendicular in Group I and Group II patients|
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[Table 6] showed a comparison of the mean angulation of articular eminence inclination between Group I and Group II patients, indicating slightly more angulation in edentulous patients (43.35°±3.23°) than dentulous patients (42.35°±1.42°) but the difference was found to be insignificant (p > 0.05).
|Table 6: Angulation of articular eminence in Group I and Group II patients|
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[Table 7] showed the t-test (tests of normality) comparison for various parameters studied in two study groups, indicating the normal distribution (p > 0.05) of various values along a different axis.
[Graph 1] showed the comparison of various linear studied variables among the two study groups.
| Discussion|| |
The remodeling is an accommodative response of bones to the applied forces for functional needs. It occurs consistently in the condylar and temporal parts of TMJs which leads to greater variation in their position and angulation. Both the condyle and the temporal component of the TMJs start undergoing remodeling associated changes after 22 years of age. The anterior aspect of condyle shows progressive remodeling while regressive remodeling can be seen on the posterior condylar aspect. This study was conducted on a similar basis to evaluate the effect of remodeling changes on condyle and glenoid fossa morphology of TMJs among edentulous patients with dentulous patients.
The ultimate goal of the clinician is to use imaging either alone or in combination with clinical examination to delineate the anatomic truth. In this study lateral cephalogram is the radiographic modality chosen to view the condyle–fossa relationship and articular eminence angulation in patients as it provides a clear lateral view of the TMJs, without many superimpositions on a single film. Also, it is easy to perform and is used as a routine diagnostic modality for orthodontics in college set up with less radiation exposure. According to the International Atomic Energy Agency, radiographic dose exposure/cephalogram exposure is 2.5μSv. The radiograph can be taken in a single shot and in a fraction of seconds, thus reducing the risk of blurred images and also increasing the compliance of the patient.
The edentulous patients chosen were specified to be edentulous for a period of 1–5 years. The mandible may move forward and upward as a result of the abrasion of natural or artificial teeth. When a patient is edentulous from a long period there is a loss of tripodization which requires each cusp contacting an opposing fossa such that it produces three contacts surrounding the actual tip.
An edentulous patient who wears dentures for quite a period will show remodeling changes but not to an extent that could be justified because a proper vertical dimension of occlusion and maximum intercuspal position has been restored thereby preventing the remodeling changes to occur. This maintains the proper functioning of the condyle and its position.
The data obtained showed greater variation in the location of the condyle in edentulous patients. In dentulous patients, teeth are in centric relation that is in an orthopedically stable position with tripodization. During the period of edentulousness, there is a loss of teeth that breaks the tripodization followed by loss of occlusal stops. As a result, there is significant upward shift in the position of the condyle in relation to the y-axis, when the distance is measured on the y-axis between the center of the condyle and glenoid fossa. The results are by the study conducted by Hatjigiorgis et al.
Lateral pterygoid is the muscle of mastication attached to the condylar neck maintaining the postural position of condyles and it also depresses, protrude, and move the mandible from side to side. The continuous myotonic contraction of lateral pterygoid pulls the condyle forward which is balanced by approximation of maxillary and mandibular teeth while in edentulous patient there is the loss of teeth. There is a loss in a stretch of functional ligaments in an edentulous patient due to age changes which justifies the forward placement of condyle. This proves the cause of decreased X-axis distance between the center of condyle and center of the glenoid fossa and N-perpendicular distance from the center of the condyle in edentulous patients. The results obtained are consistent with the study conducted by Raustia et al. and Uma P et al.
The Glenoid fossa was found to be placed more anteriorly in an edentulous patients which was evidenced by the significantly decreased distance between N-perpendicular–the center of Glenoid fossa in Group II patients. This could be because the rate of remodeling of glenoid fossa directly depends upon the edentulousness duration.
It is important to study the articular eminence angulation because remodeling changes will be reflected following both parameters angulation and height of condyle. Articular eminence despite belonging to the cranium is exposed to functional load from masticatory forces and these may in turn influence its morphology. It has been observed that extensive teeth loss would result in a decrease in fossa depth and slope with increasing wear. The posterior articular eminence slope of completely edentulous patients may show significant flattening. The age- related remodeling of articular fossa brings about an increase in articular eminence angulation in the edentulous patient as compare to dentulous patients, but the difference was insignificant.
Nowadays, doing 3D CBCT based Cephalometric analysis enabled high-resolution, distortion-free, and more accurate and reliable measurements. However, CBCT is associated with significantly higher radiation exposure than traditional routine bidimensional cephalometric examinations.
The limitations of the study included a small sample size that cannot give accurate evidence to the results. Choosing lateral cephalograph as imaging modality provides a two-dimensional view of three-dimensional structures. There can be errors in the identification of landmarks and in tracing procedures. The method is not standardized as it gives view of one side of condyle the other side being overlapped by opposing condyle. According to Ahlqvistet al., projection errors due to superimposition of landmarks in lateral cephalograms are <1, while the margin of errors due to incorrect positioning is <2.7%.
| Conclusion|| |
This study concludes that condyles were placed more upwards and forwards, while glenoid fossae were situated more anteriorly in completely edentulous subjects compared to totally dentulous subjects. Moreover, the articular eminence was found to be steeper in edentulous patients than fully dentulous but the difference was found statistically insignificant. Therefore, it is suggested that whenever there is a loss of natural teeth, they should be replaced immediately with the proper vertical dimension of occlusion and maximum intercuspal position for the function and esthetic as well as for proper positioning of the condyle and glenoid fossa.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
The study was conducted in accordance with the declaration of Helsinki and was approved by the Ethical Committee of the Institute (SDCRI/IEC/2019/212) dated 16-05-2019.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]