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 Table of Contents  
Year : 2022  |  Volume : 34  |  Issue : 3  |  Page : 300-303

Evaluation of patterns of mandibular bone invasion in CBCT of patients with oral squamous cell carcinoma: A descriptive study

Department of Oral Medicine and Radiology, Yenepoya Dental College (Yenepoya Deemed To Be University), Derlakatte, Mangalore, Karnataka, India

Date of Submission23-Mar-2022
Date of Decision28-Aug-2022
Date of Acceptance04-Sep-2022
Date of Web Publication26-Sep-2022

Correspondence Address:
P Archana
Department of Oral Medicine and Radiology, Yenepoya Dental College (Yenepoya Deemed To Be University), Derlakatte, Mangalore, Karnataka-575018
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jiaomr.jiaomr_99_22

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Background: One of the crucial factors in the pretreatment analysis of patients with oral squamous cell carcinoma (OSCC) is the detection of the presence of bony invasion. This will indicate aggressiveness, and its patterns may also express the conduct of the lesion. The extent of bony invasion by the tumor will alter the treatment planning and increases the morbidity rate and quality of life. Aim: To evaluate the mandibular invasion patterns in cone beam computed tomography (CBCT) of patients with OSCC. Methodology: A total of 31 CBCT images of OSCC involving the mandible with bony invasion were included and assessed for various invasion patterns. Bony invasion is classified into three patterns: erosive, infiltrative, and mixed. Results: Descriptive analysis was carried out to assess the frequency among various bony invasion patterns. Chi-square test was carried out to find significance between the inferior alveolar nerve canal (IANC) involvement among various patterns of OSCC, which found be to be highly significant. Conclusion: Erosive pattern is the common pattern observed and the mixed pattern was the most frequently associated pattern with the IANC involvement.

Keywords: Cone beam computed tomography, erosive, infiltrative, mandibular/inferior alveolar canal, mixed
Key Message: Each bony invasion pattern in the mandible has its own behavior that can be able to assess the aggressiveness of the lesion

How to cite this article:
Shenoy P, Archana P, Chatra L, Veena K M, Prabhu RV, Shetty P. Evaluation of patterns of mandibular bone invasion in CBCT of patients with oral squamous cell carcinoma: A descriptive study. J Indian Acad Oral Med Radiol 2022;34:300-3

How to cite this URL:
Shenoy P, Archana P, Chatra L, Veena K M, Prabhu RV, Shetty P. Evaluation of patterns of mandibular bone invasion in CBCT of patients with oral squamous cell carcinoma: A descriptive study. J Indian Acad Oral Med Radiol [serial online] 2022 [cited 2022 Dec 10];34:300-3. Available from: http://www.jiaomr.in/text.asp?2022/34/3/300/356974

   Introduction Top

Oral cancer is the sixth most common cancer worldwide with the highest incidence in South Asia.[1] It has a high fatality rate; with a 5-year survival of less than 60%.[2]

Various preoperative diagnostic imaging modalities provide information regarding extension, infiltration to neighboring structures, and distant metastasis.[3],[4] Nowadays cone beam computed tomography (CBCT) is preferred and extensively used in the maxillofacial area to analyze medullary changes and to see the extension of bony infiltration.[5],[6]

Three patterns of bony invasion suggested in the literature are the erosive, infiltrative, and mixed patterns.[7] It is a matter of debate whether these patterns suggest the aggressiveness of lesions. This study is carried out to evaluate the patterns of bony invasion and to assess a possible correlation to the involvement of the mandibular canal.

   Methods Top

This study was approved by the institutional ethics committee and issued the protocol number (190/25.1.2020/YEC2). All the procedures were in accordance with “the Helsinki Declaration” maintaining the standard ethical principles. The sample size was estimated using G* Power software with a statistical power of 90% and a significance level of 0.05. This time-bound study was carried out based on convenient sampling that includes 31 samples reported to the department of oral medicine and radiology from November 2019 to June 2021. “Descriptive statistical analysis” was done to assess the percentage distribution of various patterns of mandibular bony invasion in the sample size. The CBCT images of patients with clinically and histopathologically diagnosed as OSCC and radiologically evident mandibular bony invasion were included in this study with exposure parameters of 90 Kvp, 8 mA, and scan time of 13.6 s with exposure done with 8 × 5 cm size of feild of view in the CBCT-PLANMECA ProMax 3D Mid machine with romexis software version 3.2. In contrast, exclusion criteria include CBCT images of patients clinically and histopathologically diagnosed as OSCC in which radiologically there is no evident mandibular invasion. CBCT slices with 75 micrometers slice thickness were examined in the axial, sagittal, and coronal views. The bone invasion patterns are grouped into three categories by examining the axial section of CBCT images as the erosive pattern shows bone destruction with scalloping, smooth, and well-defined margins. A mixed pattern shows bone destruction with an irregular margin and isolated bony fragments. The infiltrative pattern shows irregular and ill-defined margins of bone destruction along with spicules or fragments of bone [Figure 1], [Figure 2], [Figure 3].
Figure 1: Erosive pattern

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Figure 2: Infiltrative pattern

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Figure 3: Mixed pattern

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Statistical analysis was done using Statistical Package for Social Sciences Software (IBM SPSS version 20.0). The Chi-square test is used to compare the involvement of inferior alveolar nerve canal (IANC) to the various bony invasion patterns. Data are expressed in terms of frequency and percentage. A P value of <0.05 was considered to be statistically significant.

   Results Top

A total of 31 samples were included in this study. The histopathological nature of the lesions has not been described as it was not the objective of this study. [Table 1] shows the distribution of various patterns of bony invasion among 31 samples. An erosive, infiltrative, and mixed patterns were observed in 14, 10, and 7 cases with a frequency of 45.1, 32, and 22.5%, respectively. [Table 2] shows the frequency of the invasion of IANC in various bony invasion patterns among 31 samples. Erosive pattern, mixed pattern, and infiltrative patterns are 21, 80, and 100%, respectively. [Table 3] shows the comparison of IANC involvement to different patterns showing 9.7% in the erosive pattern, 25.8% in the infiltrative pattern, and 22.6% in the mixed pattern.
Table 1: Distribution of various bony invasion patterns

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Table 2: Invasion of IANC in various patterns of OSCC involving the mandible

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Table 3: Comparison of the involvement of IANC in the various patterns of OSCC involving the mandible

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   Discussion Top

Oral cancer among the South Asian population, especially in the Indian subcontinent, has the highest prevalence that accounts for 90–95%.[1] The most common histological type of oral cancer is squamous cell carcinoma and includes the anatomical sub sites such as lip, buccal mucosa, lower and upper alveolus, retro molar trigone area, tongue, floor of mouth, palate, and paranasal sinus. In advanced stages, tumors from the soft tissues can invade directly into the adjacent structures, such as bone, muscle, and neurovascular tissue.[1],[2],[3] In Indian subcontinent, the incidence and prevalence of OSCC involving the mandible range from 12 to 56% and 26.67% in the maxilla.[4] In the mandible, direct infiltration occurs by seven possible routes of entry by the tumor, which include the alveolar crest, mental and mandibular foramen, secondary tumors involving the mandible, cortical bone defects in the edentulous arch, and periodontal membrane and attached gingiva in the dentulous jaw. However, the pathway of tumor entry to the mandible is mainly through the attached mucosa irrespective of the dentulous or edentulous jaw.[5] Determining the extent of bony invasion is important because it alters the Tumor (T), Nodes (N), and Metastases (M) staging that influences surgical planning.[8] Therefore, the extent of bony invasion should be assessed preoperatively through radiographic examination.[2],[4],[8]

Several radiographic imaging modalities are used to assess the extent of bony invasion but each has its own advantages. Panoramic radiograph gives a gross image of the lesion but the detailed picture of the extent with anatomical structures cannot be assessed thoroughly. Computed tomography appears to be a superior modality compared to PR because of its role in soft tissue evaluation but has a high false negative rate and also it tends to underestimate the bone involvement.[6],[7] Magnetic resonance imaging having less radiation exposure compared to the above imaging techniques is less reliable in evaluating the bony structures.[8],[9]

CBCT is also a reliable imaging modality for evaluating the depth of the tumor invasion.[10],[11] The patterns of invasion are classified into three types: erosive, infiltrative, and mixed.[8] The present study aims to evaluate various mandibular invasion patterns in OSCC. A total of 31 samples were selected for the study based on inclusion and exclusion criteria and interpreted and evaluated for various bone invasion patterns.

Out of 31 samples, the most common pattern was found to be erosive in 14 (45.1%), infiltrative in 10 (32, %), and mixed in seven (22.5%) [Table 1]. Each pattern has its own degree of conduct in the bone. Therefore, the question arises whether the pattern of bone involvement indicates the aggressiveness of the lesion.[12],[13] According to histological studies conducted by Brown et al. and Pandey et al., the size of the primary lesion is directly proportionate to aggressiveness of the pattern.[9],[14] Likewise, the depth of involvement by the primary lesion also determines its nature of the pattern. From the above statement, each pattern that is assessed will be directly related to the aggressiveness of the tumor. All these findings directly stress that the early evaluation of the bony invasion patterns should be assessed radiographically and, therefore, it acts as a prerequisite for surgical planning.[15],[11] Depending on the nature of each pattern, it appears to have distinct depth of mandibular invasion. The depth of mandibular invasion is emphasized because of an important structure, i.e, mandibular canal is passing through. The lesion involving the mandibular canal is found to be more aggressive in nature. [Table 2] depicts the frequency of the samples that shows the involvement of the canal in various patterns. In mixed pattern, all the samples (100%) are found to be involving the canal, whereas in infiltrative, 80% of the samples are involving the canal and the least involvement to the canal is noticed in the erosive (21%).[13],[16],[17] Therefore, determining the pattern as well as the depth of the tumor is the major considerations in treatment planning that can alter from segmental mandibulectomy to marginal resection or vice versa, which significantly modifies the prognosis and quality of life.[18] The current study emphasized that the assessment of bony invasion patterns on imaging tests is of fundamental significance and is a prerequisite for treatment planning that directly improves the morbidity and quality of the patient's life.

Limitations of the study

The study has certain limitations such as the primary site of the tumor and duration of the lesion should have been into consideration that could aid in determining the aggressiveness of each pattern.

Future prospect of this study

Determining the pattern of the bony invasion can have a great shift on the treatment plan that can improve the patient's quality of life.

   Conclusion Top

The present study was done to assess the evaluation of patterns of mandibular bone invasion in CBCT of patients with OSCC. A total of 31 samples were selected for the study and were evaluated for the various patterns of bony invasion. The results show the highest distribution in erosive, whereas the involvement in the mandibular canal shows the highest involvement in a mixed pattern. Therefore, further studies can be carried out to find the relationship between duration of the lesion and the involvement into the canal by each pattern that may indicate the aggressiveness of each pattern.


I would like to thank all the subjects who willingly participated in the study.

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.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Uribe S, Rojas LA, Rosas CF. Accuracy of imaging methods for detection of bone tissue invasion in patients with oral squamous cell carcinoma. Dentomaxillofac Radiol 2013;42:20120346.  Back to cited text no. 1
Ramarathinum D, Rao G, Kumar N, Anehosur V, Desai AK. Digital volume tomography in the assessment of mandibular invasion in patients with squamous cell carcinoma of the oral cavity - A prospective study. Saudi Dent J 2019;31:93-8.  Back to cited text no. 2
Pandey M, Rao LP, Das SR, Mathews A, Chacko EM, Naik BR, et al. Patterns of mandibular invasion in oral squamous cell carcinoma of the mandibular region. World J Surg Oncol 2007;5:1-6.  Back to cited text no. 3
Li C, Lin J, Men Y, Yang W, Mi F, Li L. Does medullary versus cortical invasion of the mandible affect prognosis in patients with oral squamous cell carcinoma?J Oral Maxillofac Surg 2017;75:403-15.  Back to cited text no. 4
Pałasz P, Adamski Ł, Górska-Chrząstek M, Starzyńska A, Studniarek M. Contemporary diagnostic imaging of oral squamous cell carcinoma - A review of literature. Pol J Radiol 2017;82:193-202.  Back to cited text no. 5
DeAngelis A, Breik O, Angel C, Goh C, Iseli T, Nastri A, et al. Can radiological examination of mandibular bone invasion accurately predict the need for mandibular resection in oral squamous cell carcinoma? Int J Oral Maxillofac Surg 2019;48:576-83.  Back to cited text no. 6
Shah PH, Venkatesh R, More CB, Vassandacoumara V. A retrospective radiographic analysis of osseous changes in oral malignancy. J Indian AcadOral Med Radiol 2016;28:236.  Back to cited text no. 7
Nakayama E. Imaging diagnosis for bone invasion by gingival carcinoma of the mandible: The value and the limitation. Jpn Dent Sci Rev 2009;45:23-30.  Back to cited text no. 8
Islam MA, Uddin MN, Ali MS, Hossain MM. Cone-beam computed tomography to assess mandibular invasion in oral squamous cell carcinoma. Update Dent Coll J 2018;8:18-22.  Back to cited text no. 9
Hendrikx AW, Maal T, Dieleman F, Van Cann EM, Merkx MA. Cone-beam CT in the assessment of mandibular invasion by oral squamous cell carcinoma: Results of the preliminary study. Int J Oral Maxillofac Surg 2010;39:436-9.  Back to cited text no. 10
Brown JS, Griffith JF, Phelps PD, Browne RM. A comparison of different imaging modalities and direct inspection after periosteal stripping in predicting the invasion of the mandible by oral squamous cell carcinoma. Br J Oral Maxillofac Surg 1994;32:347-59.  Back to cited text no. 11
Kushraj T, Chatra L, Shenai P, Rao PK. Bone invasion in oral cancer patients: A comparison between Orthopantamograph, conventional computed tomography, and single positron emission computed tomography. J Cancer Res Ther 2011;7:438-41.  Back to cited text no. 12
Patel RS, Dirven R, Clark JR, Swinson BD, Gao K, O'Brien CJ, et al.The prognostic impact of extent of bone invasion and extent of bone resection in oral carcinoma. Laryngoscope 2008;118:780-5.  Back to cited text no. 13
Trotta BM, Pease CS, Rasamny JJ, Raghavan P, Mukherjee S. Oral cavity and oropharyngeal squamous cell cancer: Key imaging findings for staging and treatment planning. Radiographics 2011;31:339-54.  Back to cited text no. 14
Müller H, Slootweg PJ. Mandibular invasion by oral squamous cell carcinoma. Clinical aspects. J Craniomaxillofac Surg 1990;18:80-4.  Back to cited text no. 15
Brown JS, Browne RM. Factors influencing the patterns of invasion of the mandible by oral squamous cell carcinoma. Int J Oral Maxillofac Surg 1995;24:417-26.  Back to cited text no. 16
Acton CH, Layt C, Gwynne R, Cooke R, Seaton D. Investigative modalities of mandibular invasion by squamous cell carcinoma. Laryngoscope 2000;110:2050-5.  Back to cited text no. 17
Brown JS, Lowe D, Kalavrezos N, D'Souza J, Magennis P, Woolgar J. Patterns of invasion and routes of tumor entry into the mandible by oral squamous cell carcinoma. Head Neck 2002;24:370-83.  Back to cited text no. 18


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2], [Table 3]


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