Indian Journal of Dental ResearchIndian Journal of Dental ResearchIndian Journal of Dental Research
HOME | ABOUT US | EDITORIAL BOARD | AHEAD OF PRINT | CURRENT ISSUE | ARCHIVES | INSTRUCTIONS | SUBSCRIBE | ADVERTISE | CONTACT
Indian Journal of Dental Research   Login   |  Users online: 1628

Home Bookmark this page Print this page Email this page Small font sizeDefault font size Increase font size         

 


 
Table of Contents   
ORIGINAL RESEARCH  
Year : 2014  |  Volume : 25  |  Issue : 6  |  Page : 758-761
Scanning electron microscopic observations of fibrous structure of cemento-dentinal junction in healthy teeth


1 Department of Periodontics, , Karpaga Vinayaga Institute of Dental Sciences, Chinna Kolambakkam, Palayanoor PO, Madhurantakam Taluk, Kanchipuram, Tamil Nadu, India
2 Saveetha Dental College, Chennai, Tamil Nadu, India
3 Department of Oral and Maxillofacial Pathology, Karpaga Vinayaga Institute of Dental Sciences, Chinna Kolambakkam, Palayanoor PO, Madhurantakam Taluk, Kanchipuram, Tamil Nadu, India

Click here for correspondence address and email

Date of Submission24-Feb-2012
Date of Decision19-Apr-2013
Date of Acceptance13-Jun-2013
Date of Web Publication02-Mar-2015
 

   Abstract 

Introduction: The cemento-dentinal junction (CDJ) is a structural and biologic link between cementum and dentin present in the roots of teeth. Conflicting reports about the origin, structure and composition of this layer are present in literature. The width of this junctional tissue is reported to be about 2-4 μm with adhesion of cementum and dentin by proteoglycans and by collagen fiber intermingling.
Aim and Objective: The objective of this study is to observe and report the fibrous architecture of the CDJ of healthy tooth roots.
Materials and Methods: A total of 15 healthy teeth samples were collected, sectioned into halves, demineralized in 5% ethylenediaminetetraacetic acid, processed using NaOH maceration technique and observed under a scanning electron microscope.
Results: The CDJ appeared to be a fibril poor groove with a width of 2-4 µm. Few areas of collagen fiber intermingling could be appreciated. A detailed observation of these tissues has been presented.

Keywords: Cemento-dentinal junction, healthy teeth, ultra structure

How to cite this article:
Pratebha B, Jaikumar N D, Sudhakar R. Scanning electron microscopic observations of fibrous structure of cemento-dentinal junction in healthy teeth. Indian J Dent Res 2014;25:758-61

How to cite this URL:
Pratebha B, Jaikumar N D, Sudhakar R. Scanning electron microscopic observations of fibrous structure of cemento-dentinal junction in healthy teeth. Indian J Dent Res [serial online] 2014 [cited 2019 Oct 19];25:758-61. Available from: http://www.ijdr.in/text.asp?2014/25/6/758/152196
In the past, intermediate cementum (IC) and Hopewell-Smith's hyaline layer was considered synonymous with cemento-dentinal junction (CDJ). [1],[2] However, at present it is clear that, though they are continuous, they are not one and the same, but different entities. IC and Hopewell-Smith's hyaline layer can be distinguished from the cementum by the presence of CDJ. [3],[4]

Compositionally, the CDJ constitutes of proteoglycans, non-collagenous bone related and enamel-related proteins and collagen fibers originating from dentin and cementum that intermingle at CDJ. [5] The adhesion of dentin and cementum is said to be primarily by proteoglycans and secondarily by fiber intermingling. [4] The width of CDJ is said to be 2-3 μm wide. [6]

Many studies regarding CDJ have used transmission electron microscopy (TEM) and comparatively few have used a scanning electron microscope (SEM). When extended sections of the tooth have to be examined, SEM is superior to TEM because with TEM, one can view a sample not as a whole but at one point only.

The objective of this study was to observe and report the fibrous architecture and nature of fiber intermingling and cemento-dentinal attachment at the CDJ as examined under SEM using the NaOH maceration technique.


   Materials and methods Top


A total of 15 healthy teeth extracted for orthodontic reasons and preserved in neutral 10% formalin were used for this study. We followed the methodology that was suggested by Yamamoto et al. [5],[6] in their studies. The teeth were buccolingually sectioned into two halves. Only one half of the samples were used. The samples were demineralized with 5% ethylenediaminetetraacetic acid for a period of 2-3 months and fixed in 2.5% gluteraldehyde in 0.06 M cacodylate buffer (pH 7.4) for a week. They were then immersed in 10% NaOH solution at room temperature for 2-3 days and rinsed in distilled water. NaOH maceration is said to remove interfibrillar substances without damaging collagen. The samples were then treated with 2% tannic acid (to enhance electron density of elastin and collagen apart from being a fixative and mordant [7] ) and 1% osmium tetroxide (to stabilize proteins and prevent coagulation of proteins during alcohol dehydration [8] ) both for an hour, dehydrated in a graded series of alcohol and finally samples were coated with palladium for examining under a scanning electron microscope.


   Results Top


In the 2-3 days macerated samples the CDJ appeared to be a fibril poor groove and the width measured on an average 3-4 μm.

Dentin

The identification of dentin was made easy by the presence of tubule openings [Figure 1]. Few fibers from dentin crossed the CDJ and traversed toward cementum. The contact of fibers from the dentin and cementum at CDJ were mostly point like and the intermingling was not complicated [Figure 2]. In few samples, the inner surface of dentin and cementum could be seen and there are numerous projections formed by fibers visible [Figure 3].
Figure 1: Dentinal tubules are visible. Cemento-dentinal junction appears like a groove due to demineralization exposing the fibrous architecture only. NaOH Maceration further has removed interfibrillar substance, though incompletely, in this sample. Fiber intermingling with point like contact of the fibers can be appreciated at the groove of CDJ. Intrinsic and extrinsic fibers of cementum can be appreciated along with dentin and cemental fiber orientation

Click here to view
Figure 2: Width measured at the cemento-dentinal junction is 4.5 µm at that point in the sample. The inner surface of cementum and dentin is visible. Fiber intermingling also can be seen

Click here to view
Figure 3: At higher magnification, the fibers are better appreciated; the width measured is 2.5 µm at an area of close dentin and cementum approximation

Click here to view


Cementum

The fibers, both extrinsic and intrinsic and the surface of cementum appear coarser than that of dentin [Figure 1] and [Figure 2]. In most of the specimens [Figure 1] [Figure 2] [Figure 3] [Figure 4], the dentinal fibers largely appear to be arranged parallel to CDJ, whereas the cemental fibers appear to be randomly oriented to the CDJ. Deeper layers of cementum are mostly constituted by intrinsic fibers [Figure 3] and [Figure 4]. More fibers from cementum cross over to dentin than vice versa [Figure 2]. In higher magnifications, the point like nature of fiber intermingling is clearly visible. An extended section of the CDJ flanked by dentin and cementum is clear in lower magnifications. The coarse nature of cemental fibers and the relatively smooth and organized fibers of dentin can be well appreciated [Figure 5]. The CDJ width, measured at three different points in one sample [Figure 6] had a mean of 4.1 μm. Maceration was allowed to progress for 5-6 days in two of the samples and in such samples complete detachment of dentin and cementum could be observed [Figure 7]. CDJ width measurement is not possible in such specimens as there is no approximation of the two tissues.
Figure 4: High magnification view of cemento-dentinal junction showing few areas of fiber intermingling. Width measured in this sample is 1.2 ƒÊm

Click here to view
Figure 5: Lower magnification of a longer stretch of the root surface can be appreciated. The dentin, cementum and the junctional tissue can be clearly seen. Random fiber orientation of cementum and parallel
organized fiber orientation of dentin is observed


Click here to view
Figure 6: Width has been measured at 3 points in this a sample as 4.6 ƒÊm, 4.35 ƒÊm and 3.26 ƒÊm. Very few areas of fiber intermingling are seen. Inner cementum can be observed consisting predominantly of intrinsic fibers

Click here to view
Figure 7: Prolonged maceration causing detachment of dentin and cementum. Width cannot be measured. Absence of fiber intermingling is observed

Click here to view



   Discussion Top


In previous studies, [5],[6] the CDJ was reported to be a fibril-poor groove and the width measured at the CDJ was found to be about 2-3 μm. In our study, the CDJ was observed to be a fibril-poor groove with fibers from dentin reaching cementum and vice versa, which is in accordance with other studies and the width measured at the CDJ was about 2-4 μm.

Conflicts were present regarding the cause of cemento-dentinal attachment. Bosshardt and Schroeder reported from their studies [9] that firm cemento-dentinal attachment is due to collagen fiber intermingling reinforced by mineralization. However, Paynter and Pudy [10] and Yamamoto et al. [4] reported that the attachment at CDJ was primarily due to adhesive proteoglycans and that fiber intermingling is only of secondary importance.

In our study, in all samples, CDJ appears as a fibril poor groove and this is due to dissolution of minerals and ground substance during demineralization. NaOH maceration further removed interfibrillar substance without any damage to collagen fibers. The skeletal fibrous architecture, that remains after processing suggests, that it is indeed, the adhesive proteoglycans and ground substance that primarily cause firm cemento-dentinal attachment. This observation was in accordance with the study by Yamamoto et al. [4] Moreover, the fiber intermingling along the length of roots are point like in contact with each other and there does not appear to be any complicated entanglement during intermingling. This observation of our study also lends support to Paynter and Yamvamoto's theory of the cause of cemento-dentinal attachment. A few studies observe acellular and cellular cementum in their samples and also report the fibrillar architecture of these types of cementum. But in our study, only extrinsic and intrinsic fibers of cementum could be observed to extent and the clear cut difference between acelllar and cellular cementum could not be appreciated. The reason we attribute to this is inadequate NaOH maceration of our samples. We experienced complete detachment of cementum and partial dissolution of some samples on prolonged maceration and therefore in order to be able to measure CDJ width, a 2-3 days maceration was opted for as compared with 10 days maceration technique followed in a few studies. [6],[10]


   Conclusion Top


The shear strength of this junction needs to be determined so that the impact of root planing on this junctional tissue in healthy and periodontitis affected tooth roots can be further understood.

 
   References Top

1.
Harrison JW, Roda RS. Intermediate cementum. Development, structure, composition, and potential functions. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1995;79:624-33.  Back to cited text no. 1
    
2.
Lindskog S. Formation of intermediate cementum. II: A scanning electron microscopic study of the epithelial root sheath of Hertwig in monkey. J Craniofac Genet Dev Biol 1982;2:161-9.  Back to cited text no. 2
[PUBMED]    
3.
Bosshardt DD, Schroeder HE. Establishment of acellular extrinsic fiber cementum on human teeth. A light- and electron-microscopic study. Cell Tissue Res 1991;263:325-36.  Back to cited text no. 3
    
4.
Yamamoto T, Domon T, Takahashi S, Islam N, Suzuki R, Wakita M. The structure and function of the cemento-dentinal junction in human teeth. J Periodontal Res 1999;34:261-8.  Back to cited text no. 4
    
5.
Yamamoto T, Domon T, Takahashi S, Islam MN, Suzuki R. The fibrous structure of the cemento-dentinal junction in human molars shown by scanning electron microscopy combined with NaOH-maceration. J Periodontal Res 2000;35:59-64.  Back to cited text no. 5
    
6.
Yamamoto T, Domon T, Takahashi S, Islam MN, Suzuki R. The fibrillar structure of the cemento-dentinal junction in different kinds of human teeth. J Periodontal Res 2001;36:317-21.  Back to cited text no. 6
    
7.
Hayat MA. Principles and Techniques of Electron Microscopy: Biologic Applications. 4 th ed. United Kingdom: Cambridge University Press; 2000. p. 336.  Back to cited text no. 7
    
8.
Hayat MA. Principles and Techniques of Electron Microscopy: Biologic Applications. 4 th ed. United Kingdom: Cambridge University Press; 2000. p. 45-61.  Back to cited text no. 8
    
9.
Bosshardt DD, Schroeder HE. Cementogenesis reviewed: A comparison between human premolars and rodent molars. Anat Rec 1996;245:267-92.  Back to cited text no. 9
    
10.
Paynter KJ, Pudy G. A study of the structure, chemical nature, and development of cementum in the rat. Anat Rec 1958;131:233-51.  Back to cited text no. 10
[PUBMED]    

Top
Correspondence Address:
R Sudhakar
Department of Oral and Maxillofacial Pathology, Karpaga Vinayaga Institute of Dental Sciences, Chinna Kolambakkam, Palayanoor PO, Madhurantakam Taluk, Kanchipuram, Tamil Nadu
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9290.152196

Rights and Permissions


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]



 

Top
 
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  
 


    Abstract
    Materials and me...
   Results
   Discussion
   Conclusion
    References
    Article Figures

 Article Access Statistics
    Viewed1547    
    Printed29    
    Emailed0    
    PDF Downloaded94    
    Comments [Add]    

Recommend this journal