|Year : 2005 | Volume
| Issue : 1 | Page : 6-11
A preliminary study on human interdental alveolar bone using scanning electron microscopy and energy dispersive X-ray spectroscopy
S Ranjith1, Madhavan R Nirmal2, Radha S Ramanathan1, CR Ramachandran2
1 Department of Anatomy, Rajah Muthiah Dental College and Hospital, Annamalai University, Annamalai Nagar, Tamilnadu, India
2 Department of Oral and Maxillo Facial Pathology, Rajah Muthiah Dental College and Hospital, Annamalai University, Annamalai Nagar, Tamilnadu, India
Madhavan R Nirmal
Dept of Oral and Maxillo Facial Pathology, Rajah Muthiah Dental College and Hospital, Annamalai University, Annamalai Nagar-608 002, Tamilnadu
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aim: To determine the morphology and mineralization of Sharpey's fibers in bundle bone of humans with reference to interdental area
Method: Human interdental alveolar bone between mandibular 1st and 2nd molar teeth was taken and observed under scanning electron microscope (SEM) and the constituent elements were analyzed using energy dispersive X- ray spectroscopy (EDS).
Result: Under scanning electron microscope, the Sharpey's fibers were fully mineralized and appeared as dome shaped projections in the crestal region where as in the apical region, they remained unmineralized at the centre and appeared as depressions- The results of the energy dispersive spectroscopy supported the above findings
Conclusion: The degree of mineralization decreases from crestal to apical region, indicating that, the periodontal ligament which supports the teeth matures from apical to crestal and It is fully developed in the crestal region
Keywords: Human interdental alveolar bone, Sharpey′s fibers, Mineralized tissue
|How to cite this article:|
Ranjith S, Nirmal MR, Ramanathan RS, Ramachandran C R. A preliminary study on human interdental alveolar bone using scanning electron microscopy and energy dispersive X-ray spectroscopy. J Oral Maxillofac Pathol 2005;9:6-11
|How to cite this URL:|
Ranjith S, Nirmal MR, Ramanathan RS, Ramachandran C R. A preliminary study on human interdental alveolar bone using scanning electron microscopy and energy dispersive X-ray spectroscopy. J Oral Maxillofac Pathol [serial online] 2005 [cited 2020 Jan 20];9:6-11. Available from: http://www.jomfp.in/text.asp?2005/9/1/6/39051
| Introduction|| |
The attachment of teeth to alveolar bone is by a specialised fibrous joint (gomphosis) which is made up of cementum on one side and alveolar hone on the other, connected in between, by periodontal ligament. Bundle bone is that part of the alveolar bone where the fibers of the periodontal ligament (Sharpey's fibers) are inserted and the origin of which is attributed to the dental follicle  .
Most of the scanning electron microscopic studies on bundle hone and Sharpey's fibers of the periodontium have been carried out in lower animals such as rodents , . Those few studies in humans were concerned with cemental part of tapers than the alveolar part  . The aim of this study was to observe the morphology of periodontium associated with mineralization especially, the interdental hone by scanning electron microscopy (SEM) and to determine the distribution of inorganic elements in bundle home with the help of energy dispersive x - ray spectroscopy (EDS).
| Method|| |
Human interdental septum between mandibular 1 st and 2 nd molar teeth of either side was chosen for the study.
A total of five samples were taken from the department of Oral and Maxillofacial Pathology, Rajah Muthiah Dental College and Hospital. All the samples were taken front male patients of age group of 40 to 50 years- The normal interdental bone was obtained From edges of postoperative biopsy specimen of patients who underwent hemi-mandibulectomy for various reasons. The specimens with any lesions on the molar region were not included for the study.
The interdental septum between 1 st and 2 nd molar along with the periodontal ligament and the teeth was resected from each mandible with the help of an osteotome. The teeth were removed carefully under dissection microscope- The samples were fixed in 10% neutral buffered formalin for 24 hours, rendered inorganic by immersing in 5.25%, sodium hypochlorite solution, rinsed in cacodilate buffer (0.05 M, pH 7.2), and post fixed with osmium tetroxide (1% in cacodilate butler 0.05 M, pH 7-2) for 1 hour. After the specimens were dehydrated with graded acetone, they were 'critical point dried', mounted on stubs, and sputter coated with platinum (platinum to torgate, Jeol JFC 1600, Japan). The specimens were observed tinder scanning electron microscope (Jeol-JSM-5610 LV, Japan) and photographed at 100X and 400X magnifications.
The constituent elements were analyzed using energy dispersive x - ray spectroscopy (Oxford, England), which provided data on the distribution of inorganic elements (x-ray emission from surface). The observation of samples was done at two different levels, crestal and apical, for each specimen- Data were analyzed statistically.
| Results: SEM observation|| |
In the apical region, the arrangement of Sharpey's fibers became interrupted forming islets of gradually smaller size and number. Sharpey's fibers remained unmineralized at the center. In an anorganic specimen, these fibers were removed and the area appeared as depressions. Within the depression, the Sharpey's fibers were partly mineralized, showing fascicles of calcified fibers running from the periphery to the center of the depression separated by grooves of unmineralized material [Figure - 1],[Figure - 2].
In the coronal most part, most of the Sharpey's fibers were fully mineralized and arranged in compact longitudinal rows. In hone rendered inorganic, the fully mineralized Sharpey's fibers appeared as dome shaped elevations [Figure - 3],[Figure - 4]
| RESULTS: EDS observation|| |
In the apical part. of the interdental alveolar bone, the values of weight % for silica, phosphorus, calcium. aluminium, and iron were 6.54, 2152, 53.71 7.91, and 9.45 respectively- The atomic % for silica, phosphorus, calcium, aluminium, and iron were 842, 2644, 48.89, 9.97, and 6.27 respectively. (Illustration 1, 2)
In the crestal part of the interdental alveolar bone, the values of weight % for silica, phosphorus, calcium, aluminium, and iron were 8.95, 26.92, 57.88, 6.06, and 0.19 respectively. The atomic % for the same were 11. 12, 31.00,50.82, 7.32. and 0.23 respectively. (Illustration l, 2)
All the values along with mean values, standard deviation, and the level of significance for both apical and crestal interdental hones were plotted (Illustration 2, 3).
| Discussion|| |
Alveolar process is one of the three supporting structures of the teeth and along with the other two, namely, cementum and periodontal ligament, constitutes the periodontium. It may be defined as that part of the mandible and maxilla that. surrounds and supports the teeth  . The alveolar process consists of a thin wall of compact hone that lines the tooth socket namely, cribriform plate (lamina dura, true alveolar hone, alveolar bone proper), surrounded by cancellous bone and facial and lingual plates.
Bundle bone is that par of the alveolar bone where the fibers of the periodontal ligament (Sharpey's fibers) are inserted. In our previous study, it was observed that the course of the Sharpey's fibres traverse the alveolar process, particularly towards the apical region, and continue to mingle buccally with the fibres of the periosteum covering the alveolar process  .
Studies on bundle bone and Sharpey's fibers of the periodontium using scanning electron microscope have been carried out in lower animals such as rodents , . The cemental part of the Sharpey's fibers have been subjected to study in humans rather than the alveolar part  . Sloan (1981) observed the distribution and form of alveolar Sharpey's fibers in rat, rabbit, macaque, and humans  . Though rodent teeth have been used in innumerable studies, there still exist differences from humans such as the absence of periodontal ligaments in the anterior aspect of rat central incisors  . Hence this study has been aimed to broaden the knowledge about the surface characteristics of bundle boric, Sharpey's fibers, and their maturation pattern in humans. The study is restricted to the interdental septum between the mandibular 1 st and 2 nd molar teeth of either side due to the limited availability of samples.
The morphology of Sharpey's fibers in rat incisors were studied under SFM by Boyde and Jones 1968  . The surface topography of the alveolar boric shows various irregularities in different areas. Miralva AJS and Merzel J (2004), observed in inorganic inter dental hone, two different types of Sharpey's fiber insertions. They were rounded or oval depressions when the bone was unmineralized or partly mineralized and as dome shaped projections when fully mineralized  .
Accordingly, when the apical region of interdental bone was observed, in anorganic specimens, the Sharpey's fibers were removed and the area appeared as depressions indicating that the fibers remained unmineralized at the center surrounded by a rim of calcifed sheath [Figure - 2].
In the alveolar crest region, the Sharpey's fibers insertion appeared as dome shaped projections indicating that the fibers were fully mineralized [Figure - 4]. The degree of mineralization of Sharpey's fibers and their form of projections in relation to boric surface, has been related to their mechanical effectiveness. The results herein described were in line with the observations by Chiba et al in 1990  and Komatsu et al in 1998  that the mechanical properties of periodontal ligament increases in crestal direction. It was also shown in rat incisors that the molecular organization of the periodontal ligament collagen fibers increases from apical to crestal region  .
In the coronal most part of the alveolar crest region, the Sharpey's fibers were characteristically arranged in longitudinal rows. This gradient of Sharpey's fibers density is an indication that the function of the periodontal ligament increases in direction to the crestal end of the socket to provide support, being fully developed near the coronal end. Similar findings were also observed in the rodents , . There still exists considerable confusion in reasoning these surface characteristics. Many authors attributed this to the functional remodeling of bone. It is a well known fact that the highest rate of bone resorption and formation occurs in the cribriform plate of alveolar hone  . Boyde and Hobdell attributed the surface topography of mineralized boric to the metabolic activity of bone cells and suggested that the forming bond exhibited knobby projections which represent foci of mineralization, while reasoning bones were scalloped and resting surfaces were smooth  . On the other hand, Jones and Boyde (1974) suggested that the Sharpey's fibers projecting from the hone may be related to resting bone surface and depressions to bone forming surface  .
The composition of alveolar hone is similar to that of any other bone in the body. Boric derives its characteristics of firmness, rigidity, and elasticity from the unique composition and organization of its matrix. Its basic structural unit is the osteon, which consists of organized lamellae of collagen that have become embedded with crystals of inorganic salts, principally calcium and phosphate. These salts, deposited as flat crystal plates of hydroxyrpatite, constitute about 60 70% of the bone matrix. On comparing cementum and bone, Cool et al (2002) suggested that both are similar tissues comprising mainly hydroxyapatite crystals in a collagen matrix  .
The constituent elements obtained using energy dispersive x - ray spectroscopy (Oxford, England) were analyzed and significant values were obtained for the minerals calcium, phosphorus, aluminium, silica, and iron.
The values of weight % and atomic % in the apical part of interdental septum for silica (6.54 and 8.42 respectively), phosphorus (22.52 and 26.44 respectively), and calcium (53.72 and 48.89 respectively) were found to he lesser than the crestal part (8.95 and 11.12 for Si, 26.92 and 31.00 for phosphorus, and 57.88 and 50.82 for calcium respectively). However the values of weight % and atomic % in apical part of the interdental septum for aluminium (7.91 and 9.97 respectively) and iron (9.45 and 6.27 respectively) were found to be more than in the crestal part (6.06 and 7.32 for Al and 0.19 and 0.23 for Fe respectively) (Illustration 2)
The mean difference was found to be statistically significant (p<0.01 for Al, Si, P, he and p<0.05 for Ca) and supports the SEM finding that the crestal region is more calcified or mineralized than the apical region of the interdental alveolarbone.
Hence it can be concluded that there is a significant difference in mineralization between the crestal and apical part of the alveolar boric. The degree of mineralization decreased from the alveolar crest to apical region suggesting that the Sharpey's fibers mature front apical to crestal region. Whether these changes represent a state of normalcy, or age related. or, representing functional adaptation, can be proved only by further research and systematic analysis.
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7]