Journal of Indian Society of Periodontology

: 2014  |  Volume : 18  |  Issue : 4  |  Page : 482--487

Correlation of the interdental and the interradicular bone loss: A radiovisuographic analysis

Vishakha Grover1, Ranjan Malhotra1, Anoop Kapoor2, Chahat Singh Mankotia1, Rupika Bither3,  
1 Department of Periodontics and Oral Implantology, National Dental College and Hospital, Gulabgarh, Derabassi, Punjab, India
2 Department of Periodontics and Oral Implantology, M.N.D.A.V Dental college and Hospital, Solan, Himachal Pradesh, India
3 Department of Periodontics and Oral Implantology, Laxmi Bai Dental College, Patiala, Punjab, India

Correspondence Address:
Vishakha Grover
3192, Ground Floor, Sector 37 D, Chandigarh


Background: Presence of furcation involvement indicates advanced periodontitis, and a potentially less-favorable prognosis, for the affected tooth and its diagnosis has always been an enigma. The present study was carried out to measure and correlate the interdental and interradicular bone loss in patients suffering from periodontitis using radiovisuography (RVG) for the purpose of early furcation diagnosis. Materials and Methods: A total of 50 patients suffering from chronic generalized periodontitis and with furcation involvement in mandibular molars were selected. Under standardized conditions, RVGs were taken and the morphologic measurements defining the furcation areas were recorded and analyzed. Result: Interradicular bone loss of about 0.8 mm or more, was observed in the study subjects only when the bone loss at the interdental area was minimal of 3.7 mm. The correlation between the interradicular and the interdental bone loss was statistically highly significant (T-test, P < 0.001). A stronger correlation was observed in subjects above 40 years of age as compared with the younger subjects. There was not much difference in the degree of correlation between the interradicular and the interdental bone loss when compared in the context of gender. Conclusion: The very first millimeter of interradicular bone loss was seen when the interdental bone loss was around 4 mm. Therefore, to detect the earliest lesions of furcations, the interdental bone loss can be kept as an approximate guide for the comprehensive diagnosis and management of such sites/patients. The current investigation paves the path for future longitudinal studies with larger samples to ascertain these findings.

How to cite this article:
Grover V, Malhotra R, Kapoor A, Mankotia CS, Bither R. Correlation of the interdental and the interradicular bone loss: A radiovisuographic analysis.J Indian Soc Periodontol 2014;18:482-487

How to cite this URL:
Grover V, Malhotra R, Kapoor A, Mankotia CS, Bither R. Correlation of the interdental and the interradicular bone loss: A radiovisuographic analysis. J Indian Soc Periodontol [serial online] 2014 [cited 2022 May 28 ];18:482-487
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Periodontal disease is one of the most prevalent afflictions worldwide. [1] It is a chronic inflammatory disease that is triggered by host immune responses to colonization with pathogenic periodontal microorganisms organized in biofilms and often modified by exogenous factors such as smoking. If left untreated, the disease continues with progressive alveolar bone destruction, leading to increased tooth mobility and subsequent tooth loss.

The term "furcation involvement" refers to the invasion of the bifurcation and trifurcation areas of multi-rooted teeth by periodontal disease. [2] The presence of furcation involvement or interradicular bone loss is one clinical finding that can lead to a diagnosis of advanced periodontitis and potentially to a less-favorable prognosis for the affected tooth or teeth. [3] Higher mortality and compromised prognosis for molars with furcal involvement have been reported in several retrospective studies of tooth loss. [4],[5]

Several morphological factors such as furcation entrance width, root trunk length and the presence of root concavities, cervical enamel projections, bifurcation ridges and enamel pearls contribute to the etiology and compromised prognosis of furcation-involved teeth. [6] Moreover, the responsiveness to therapy may be complicated by the presence of a greater radicular surface potentially offered to bacterial toxins and calculus buildup as compared with defects surrounding single-rooted teeth. [7] Finally, the distal location in the arch and the difficult access may conceivably impair both self-performed and professional plaque control procedures in the furcation area, limiting their effectiveness. [7] Therefore, furcation defects represent a formidable problem in the treatment of periodontal disease [7] thus necessitating an early diagnosis and treatment, which are critical to the long-term success.

However, the diagnosis of furcation involvements itself has always been an enigma, with different incidence estimates. [8],[9],[10],[11] With the current conventional diagnostic procedures, the recognition of a large clearly defined radiolucency in the furcation area presents no problem, but less clearly defined radiographic changes produced by initial or early lesions are often overlooked. [12] The inherent limitations associated with current diagnostic procedures further limit the sensitivity and reliability of furcation diagnosis. [13],[14],[15],[16],[17],[18],[19],[20] Clinical probing is dependent on a multitude of technical factors, e.g., the probing force, angulation, reference for measurement, etc., while radiographs may over- or underestimate the amount of bone loss due to projection errors and lack of three-dimensional (3D) information. [21]

Ross and Thompson (1980) reported that clinical examination alone detected furcation involvement in only 3% of maxillary and 9% of mandibular molars. The combination of radiographic and clinical examinations improved detection to 65% in maxillary molars but only 23% in mandibular molars. [11]

Further, although transgingival probing or sounding under anesthesia confirms the extent and configuration of the furcation defects, [22] it must be remembered that the information is still blind, even though it is better than probing alone. [23]

Recent techniques such as 3D computed tomography (CT) and cone-beam computed tomography (CBCT) offer high resolution and are equivalent to macroscopic evaluation of furcations; however, high exposure to radiation of high-risk organs in the skull as well as the technical difficulties and the costs involved are still a concern for the routine clinical diagnosis.

The need of the hour is to look out for some a simple, less-elaborate, time- and cost-efficient diagnostic tool or guide to screen and select such patients and/or sites that need careful comprehensive examination, diagnosis and timely intervention of furcation lesions at their earliest, so that the best clinic outcomes can be reached out. The present cross-sectional investigation aims to correlate the interdental and interradicular bone loss in chronic periodontitis patients so as to explore the potential of interdental bone loss as a rough approximate screening tool for early furcation diagnosis.


Fifty patients suffering from chronic generalized moderate to advanced periodontitis were selected from those visiting the outpatient department of Periodontology and Oral Implantology of our institute. Periodontitis was diagnosed according to the 1999 American Academy of Periodontology classification by measuring pocket probing depth, attachment loss and bleeding on probing (BOP) and by examining radiographs. [24] Patients were diagnosed as moderate and advanced cases of periodontitis on having an attachment loss of 4-6 mm and ≥6 mm, respectively.

The study protocol was approved by the institutional ethical committee. The complete history of the patients was taken followed by a detailed clinical examination. The purpose and procedure of the study was explained to patients and an informed consent was obtained for voluntary participation in the study.

For subject selection, the criteria were:

Inclusion criteria

Patients suffering from moderate to advanced periodontitis were selected, based upon the American Academy of Periodontogy (AAP) criteria of clinical attachment level (CAL) >3 mm in 30% or more sitesWell-aligned mandibular molars with no spacing, no crowding, no rotation and no intrusion or extrusion were includedPatients between the age group of 20 and 75 yearsPatients who were willing to consent for the study.

Exclusion criteria

Patients suffering from gingivitisPatients on any medication known to cause a risk for gingival hyperplasiaAny systemic disease/condition that can cause gingival enlargement, e.g., leukemia, etcPatients who had undergone surgery in the last 6 monthsMolars with fused rootsOpen contacts with respect to mandibular molarsCrowding with respect to mandibular molarsPatients with limited mouth openingSubjects with intraoral conditions present that interfere with clinical/radiographic evaluation such as orthodontic wire, extensive restorative work, shallow palatal vault, excessive calculus, no identifiable cementoenamel junction (CEJ)Pregnant women.

An initial diagnosis of periodontitis was made based on the clinical findings. Mandibular molars with furcation involvement were included in this study.

The patient was seated in an upright position in the dental chair and shielded with a lead apron, with proper adherence to radiation safety standards. Under aseptic conditions, radiographic assessment was carried out with the help of radiosvisiography (RVG) on the mandibular first molars. Radiovisuographs were taken by the paralleling (or long cone) technique using holders.

The sensor covered with a disposable plastic sheet was placed into the patient's mouth using a plastic holding device with an attached ring that projects out of the mouth. The patient was asked to bite firmly on to the film-holding device to keep the film positioned properly and ensure that it remains stable. Once the sensor was positioned, the cone of the X-ray unit was directed toward the sensor using the ring holder to help guide its position.

Then, the sensor was exposed to radiation to obtain the radiovisuograph RVG keeping the following guidelines in mind: [25]

The radiograph should show the tips of the molar cusps with little or none of the occlusal surface shownEnamel caps and pulp chambers should be distinctInterproximal spaces should be openProxial contacts should not overlap unless teeth are out of line anatomically.

All RVGs were evaluated and radiographs that did not fulfill the above criteria were repeated.

The following measurements were recorded [Figure 1]:{Figure 1}

CEJ-AC →Cementoenamel junction line - alveolar crest (in horizontal bone loss)CEJ-BD →Cementoenamel junction line - apical extension of the bony defect (in angular bone loss)CEJ (Rest)-AC →Cementoenamel junction (restoration) - alveolar crest - interdental bone loss/bone defectFx-BL →Furcation fornix - bone level - the distance from the furcation fornix to the intact interradicular bone (interradicular bone loss). [26],[27]

If the CEJ was destroyed by a restoration, its margin was taken as reference. BD was defined as the most coronal point where the periodontal ligament space showed a continuous width. If no periodontal ligament space was identified, the point where the projection of the AC crossed the root surface was taken as the landmark. If both structures could be identified at one defect, the point defined by the periodontal ligament was used as BD. If several bony contours could be identified, the most apical that crossed the root was defined as the BD. [28],[29],[30]

These were measured by a single examiner to avoid error due to interobserver variation using the digital software, the "Kodak dental imaging software," installed within the RVG.

The statistical analyses were as follows:

The mean values for the mesial interdental bone loss, the distal interdental bone loss and the interradicular bone loss were calculated. Differences among means were compared using the two-tailed t test. The correlations for the mesial and the distal interdental bone loss to the interradicular bone loss were analyzed using the Pearson correlation coefficient, which was considered significant at the 0.01 level.


The study population consisted of a total of 50 patients, with a male: female ratio of 2.12:1. The age range was from 20 years to 75 years.

The mean values of mesial and distal interdental bone loss and interradicular bone loss are shown in [Table 1] [Figure 2].{Figure 2}{Table 1}

Correlation between interdental and interradicular bone loss was highly significant, and is shown in [Table 2] [Figure 3] and [FIgure 4].{Figure 3}{Figure 4}

Correlation between interdental and interradicular bone loss based on age and gender is summarized in [Table 3].{Table 2}{Table 3}


The prevalence of involvement in the furcation area in the maxillary and mandibular molars ranges from 25% to 52% and from 16% to 35%, respectively [31],[32],[33],[34] Teeth with furcation involvement are 2.5-times more likely to lose attachment as compared with teeth without furcation involvement. [35] Proper diagnosis of the furcation lesion and knowledge of furcal anatomy are the cornerstones for optimal therapy, for which the clinician has relied on data from clinical examinations and radiographs. However, as a general rule, bone loss is always greater than it appears in the radiograph. [3] Therefore, it is possible for furcation involvement to be present without radiographic changes. [3] Variations in the radiographic technique may obscure the presence and extent of furcation involvement. [3] A tooth may present marked bifurcation involvement in one film but appear to be uninvolved in another. [3]

The aim of our study was to correlate the interdental and interradicular bone loss in chronic periodontitis patients to explore the potential of interdental bone loss as a rough approximate screening tool for early furcation diagnosis.

With regard to methodology, digital radiography was used in the present study for the evaluation of bone loss, whereas earlier studies used intraoral periapical radiographs and bitewing radiographs for the analysis of bone loss. [36],[37],[38] RVG offered the advantage of speed of image capture and display, low X-ray exposure, ability to manipulate the image and maximize diagnostic efficacy, use of digital tools (such as linear, angular and density measurements), improved patient education, ease of storage, transfer and copying and seamless integration with, electronic patient record management or other software. [3]

The results of the present investigation revealed that the smallest amount of interradicular bone loss of approximately 0.80 mm and above was observed only when the bone loss at the interdental area was equal to or exceeded 3.70 mm. These findings are drawn as overall linear measurements from radiographic interpretation, whereas the effects such as root trunk length, root length, root form, interradicular dimension, anatomy of furcation, cervical enamel projections and presence of restorations could not be addressed.

The findings of the present investigation are consistent with the results of the study conducted by Papova et al., where the furcation bone loss with ranges of 1 mm and above were in correlation with interdental bone loss of above 4 mm. [38]

In the present study, it was seen that values ranging from 2.40 to 10.50 mm for the mesial and those ranging from 2.90 to 12.90 mm for the distal interdental bone loss were associated with interradicular bone loss in the range of 0.80-9.70 mm, and both were significantly correlated with each other (P < 0.001).

Greater degree of correlation between the interdental (both mesial and distal) and the interradicular bone loss was seen in subjects above 40 years of age. This is supported by the fact that the prevalence and severity of periodontitis in a population are reported to increase with age. Older people tend to have less bone support. [39],[40],[41],[42]

With regard to gender, females were seen to have a greater degree of correlation for interdental (mesial) to interradicular bone loss and males had a higher correlation for interdental (distal) to interradicular bone loss. Thus, based on gender, there was not much difference between the correlation between the interradicular to the interdental bone loss. This is supported by a longitudinal study by Rohner et al., [37] in which age, sex and professional status did not seem to affect the annual resorption rate of alveolar bone. Also, in a study of the rate of bone loss in furcation-involved molars, [43] the gender difference did not reach a significant difference in bone loss. However, contrary to our results, age was not significantly associated with bone loss in this study.

In addition to the above, the assessment of the interdental bone loss can be used as a screening tool to detect the disease in the earliest stage. Because treatment of furcation involvement in its advanced stage is complex, expensive, time-consuming and requires an interdisciplinary approach, correction in its infancy via exclusive periodontal intervention appears quite promising to upgrade the total periodontal treatment success. With an interdental bone loss of 3-4 mm, a comprehensive examination of the furcation areas is recommended and such patients should be recalled on more frequent intervals to prevent the further progression of periodontal disease thus improving the prognosis. This can be particularly of benefit while a large number of patients are to be examined, such as in mass examinations, dental camps and community surveys, may be in very busy and heavy clinical practices, for general dentists so as to select patients for specialist's referral even in medically compromised patients, where our focus is to minimally insult the tissue, so only the areas that needs comprehensive examination can be selectively probed to reduce the incidence of bacteremia.

Within the limitations of the present investigation, our finding demonstrated that interradicular bone loss associated with the progression of bone destruction in multirooted teeth of patients with chronic periodontitis has a significant correlation to the loss of bone in the interdental area. The very first millimeter of interradicular bone loss is seen when the interdental bone loss is around 4 mm. Therefore, to detect the earliest lesions of furcations, the interdental bone loss can be kept as an approximate guide for the comprehensive management of such patients. This correlation suggests that if the disease progression is halted when the interdental bone destruction has just ensued, it may lead to an improved prognosis for the interradicular areas.

Results obtained from this research can be applied clinically to improve the diagnostic, predictive value and significance of clinical evaluations of furcation-involved teeth. Further studies with larger samples should aim to confirm these results and to identify further influencing factors.


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