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 Table of Contents  
Year : 2019  |  Volume : 5  |  Issue : 2  |  Page : 56-61

Accuracy of smartphone based photography in screening for potentially malignant lesions among a rural population in Tamil Nadu: A cross-sectional study

1 Department of Public Health Dentistry, Ragas Dental College and Hospital, Chennai, Tamil Nadu, India
2 Department of Public Health Dentistry, Sree Moogambigai Dental College and Hospital, Kanniyakumari, Tamil Nadu, India

Date of Web Publication23-Sep-2019

Correspondence Address:
Ravi Karthikayan
Department of Public Health Dentistry, Ragas Dental College and Hospital, Uthandi, ECR, Chennai, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/digm.digm_29_18

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Background and Objective: Oral cancer is a major public health problem which carries significant morbidity and mortality. A shift from treatment to prevention by screening is the key to reduce oral cancer lesion among population. Searching for an affordable and viable alternative to face-to-face screening that can expedite diagnosis of oral diseases among rural population with good accuracy is mandatory. One of the most realistic solutions to acknowledge this hurdle and the unavailability of dental professionals, is mobile teledentistry. Materials and Methods: Secondary data analysis was conducted, in which the data were derived from the project of “Oral Cancer Screening Program in Rural population” conducted by Thirumalai Mission Hospital, Ranipet. Ninety-six biopsies were taken for the patients who had visible oral lesions which had been provisionally diagnosed on clinical examination. Oral screening was carried out by unaided face-to-face screening method by a trained and calibrated dentist. In a separate subsequent visit, a trained teledental assistant took photographs of each participant's mouth by using a smartphone camera; the charting of the photographs was conducted independently by two dentists. Results: Intra-examiner reliability of Examiner 1 and Examiner 2 was 0.943 and 0.921, respectively. Inter examiner reliability score of 0.879 was obtained between both the examiners by the photographic method of diagnosis. Intraclass correlation coefficient between two methods of examination was 0.812. Agreement between the photographic examination (Examiner 1, Examiner 2) with the gold standard biopsy report was 0.791 and 0.855, respectively. Conclusion: Smartphone camera use offers a valid and reliable means of remote screening for oral lesions. Photographs of the oral lesions taken from the smart-phone camera with an acceptable diagnostic validity and reliability.

Keywords: Oral malignant lesions, smartphone photographs, teledentistry

How to cite this article:
Karthikayan R, Sukumaran A, Diwakar MP, Raj V B. Accuracy of smartphone based photography in screening for potentially malignant lesions among a rural population in Tamil Nadu: A cross-sectional study. Digit Med 2019;5:56-61

How to cite this URL:
Karthikayan R, Sukumaran A, Diwakar MP, Raj V B. Accuracy of smartphone based photography in screening for potentially malignant lesions among a rural population in Tamil Nadu: A cross-sectional study. Digit Med [serial online] 2019 [cited 2023 Mar 29];5:56-61. Available from: http://www.digitmedicine.com/text.asp?2019/5/2/56/267609

  Introduction Top

Oral potentially malignant disorders (OPMDs) include a variety of lesions and conditions in which there is an increased risk of malignant transformation (MT) into oral squamous cell carcinoma.[1] Leukoplakia, erythroplakia, melanoplakia, oral submucous fibrosis, and indolent ulcers are the most common OPMDs. The estimated annual frequency of MT of these oral precancerous lesions ranges from 0.13% to 2.2%.[2] It is currently accepted that the histopathological features of a given lesion are the most useful risk indicators of MT. Low- and middle-income countries have limited health-care resources (including manpower) available for screening cancers.[3] Therefore, costs and benefits are assessed and the most cost-effective approach is identified.[4] The oral cancer is a significant public health problem which carries significant morbidity and mortality.[5] Thereby, screening is the key to reduce or prevent the oral cancerous lesion among population and screening of oral lesions in most earlier stage, leading to significant reduction in mortality and morbidity rate rather than treating cancers.[6]

High risk potentially malignant lesions can be easily detected by periodic examination of the oral cavity. Numerous method of oral screening have been tried over the past 3–4 decades varying success rates.[7] Visual screening of the oral cavity has been widely attempted for its feasibility, safety, acceptability, and accuracy to detect oral lesions. A mass screening for oral cancer is the key way for reducing or preventing the incidence of oral cancer among the population.[8]

Healthcare professionals reaching rural/remote areas to assess their oral health has been challenging due to very long travel time, and financial problem. Although unaided face-to-face screening has remained the gold standard approach for the oral screening. This method is inadequate for large epidemiological surveys as it requires much economic and human resources. Searching for an affordable and viable alternative that can expedite the diagnosis of oral diseases among the rural population while maintaining a good level of diagnostic accuracy is mandatory. Hence, a realistic solution to acknowledge this hurdle is mobile teledentistry.[9] Teledentistry is a combination of telecommunication and dental care.[10] The term was first used by Cook in 1997 he defined teledentistry as the practice of using video- conferencing technologies to advice the treatment based on diagnosis over a distance.[11] Mobile teledentistry is a subset of telemedicine that incorporates cellular phone technology and store-and-forward telemedicine into oral care services. The origin of teledentistry may be accredited to the US Army's Total Dental Access Project, a military assignment of the United States Army (1994) that aimed to impart dental education and improve patient care.[12] It is an effective method for partial or complete management for the people who are located far away from the reach of health centers or dental professionals.[13] Teleconsultation through teledentistry can take place in either of the following way-“Real Time Consultation” and “Store and Forward Method.”[14] Few other techniques explored in the literature were “Remote Monitoring Method” or “Near Real Time consultation” (Birnbach, 2000). Real-time consultation uses video conferencing where dental professionals and patients communicate from a distinct locations. Store-and-Forward Method involves the exchange of clinical information, static images for consultation and treatment planning.[15]

Mobile teledentistry is a proportion of telemedicine that includes mobile phone technology and store-and-forward telemedicine which can be incorporated into oral health-care services.[16] All mobile smartphones have built-in camera, mobile connectivity and are readily attainable at even low cost.[17] These technologies can be combined to create an effective teledentistry screening alternative.[18] Eventhough dental photography becoming an integral part of daily dental practice, its rarely been used for diagnosis, consultation or referral in routine practice.[19] Recent documentation denotes that the diagnostic effect of photographic methods in the detection of oral diseases is commensurate to the traditional face-to-face approach.[20]

Camera-equipped smartphones are easily available, affordable, portable, easy to handle, and can produce good-quality images.[21] The power of cellular technology enables their usage in various assignment such as processing, storing, and subsequent sharing of images. Their introduction into other health disciplines, in particular, teleaudiology and teledermatology shown to be beneficial.[22] Numerous studies related to teledentistry have been conducted using DSLR or intraoral cameras to evaluate the accuracy and reliability of photographic methods in oral health screening; however, evidence on the use of smartphone cameras in epidemiological dental research is rare.[23] In the view of limitated face-to-face screening approach toward the finding of well-grounded and affordable screening solution, the purpose of this study to assess the accuracy of smartphone-based photography in screening for potentially malignant lesions among a rural population in Tamil Nadu.

  Materials and Methods Top

Study sample

This study was conducted by the data which was collected from the project conducted by Thirumalai Mission Hospital, Ranipet. The Original study was conducted to estimate the prevalence of tobacco users among the rural population and identify the patients with potentially malignant lesions via oral screening. From the people examined, 456 were tobacco users and 938 were Non users identified and 96 biopsies were taken for the patients who had visible oral lesions which has been provisionally diagnosed on clinical examination. Oral screening was carried out through unaided face to face screening method by a trained and calibrated dentist. The face-to-face assessment details were recorded on an oral screening form. In a separate subsequent visit, a trained teledental assistant either dentist or dental assistant took photographs of each participant's mouth by using a smartphone camera. The teledental assistants were provided with a photography protocol and received hands-on training on how to capture good quality images. Only the room lighting and built-in flash of the smartphone camera were used during the photography. Neither cheek retractors nor intraoral mirrors were used during photography. Then, photographs of the oral lesions were standardized using a Samsung J5 smartphone with 8-megapixel camera, resolution of 960 × 1280 pixels and LED flashlight. Photographs were taken in a examination room of Thirumalai mission hospital. Only the room lighting and built-in flash of the smartphone camera were used during the photography [Figure 1]. Photographs were saved in jpg image format. The files were transferred immediately to the computer and a backup file was created on a hard disk at the end of every day's screening to secure recorded photos. A minimum of three images per patient were taken, i.e. - the front, right lateral and left lateral views [Figure 2]. Respective biopsy specimens were transferred from Thirumalai Mission hospital to the Department of Oral and Maxillofacial Pathology, Ragas Dental College for further investigation. From that archived data, we extracted a sample of 51 participants (n = 51) data as our target population for the original study. Before commencement of the study, prior permission was obtained from Thirumalai mission hospital for using archived records of their patients.
Figure 1: Illustration showing dental photography of oral mucosal lesions taken by dental assistant

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Figure 2: Intraoral photograph shots taken by smartphone

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Screening procedures (photographic method)

Dentists were trained and calibrated for photographic assessment of oral lesions. The charting of the photographs was conducted independently by two dentists, Dental photographs were charted without any knowledge from the results of the benchmark standard. Both the dentists received instructions, reviewed photographs, thereby inserting findings and submitted their reports into the system [Figure 3]. These independent assessment by dentists were compared to the benchmark face to face assessments. Both the visual and photographic method of screening were compared with the gold standard biopsy method.
Figure 3: Examiners (charters) charting the diagnosis of photographic images of the lesions

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Statistical analysis

The data collected was compiled using MS office Excel, and it was subjected to Statistical analysis using IBM corp Statistical Package for social sciences, version 20.0. NY, USA. Descriptive statistics was used to analyze the data. Intra- and inter-examiner reliability scores were calculated. Correlation between different methods of diagnosis was analyzed. Reliability analysis using intra class correlation coefficient (ICC) for the two diagnostic techniques was obtained.

  Results Top

This study evaluated 51 biopsy reports of the suspected lesions of the patients, and no technical problems were detected in the store-and-forward system during the study.

Intraexaminer reliability shown by the Examiner 1 was the value of 0.921 and examiner 2 was 0.943.

Interexaminer reliability score of 0.882 was obtained between both the examiners by the photographic method of diagnosis. The high kappa scores illustrated good reliability between the two examiners [Table 1].
Table 1: Intra. and inter-examiner reliability of the two examiners by photographic method of assessment

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ICC was calculated between the two methods of examination (Face to Face examination and photographic methods). The value of 0.812 was obtained between the same [Table 2].
Table 2: Intra class correlation value between face-to-face examination and photographic method of examination

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[Table 3] and [Table 4] show agreement between the photographic examination (Examiner 1, Examiner 2) with the gold standard biopsy report. When the first photographic diagnosis made by the examiners for each case was considered exclusively, Examiner 1 made a correct diagnosis in 38 cases (75%), and the agreement between the examiner 1 diagnoses and the gold standard was good (κ = 0.791). Examiner 2 made the correct diagnosis in 39 cases (76%), and the agreement between the examiner 2 diagnosis and the gold standard was also considered good (κ = 0.855). When the second diagnosis for each case was considered, there was an increase in the number of correct diagnosis for both Examiners. Examiner 1 made 41 correct diagnosis (81%), and the agreement between the examiner 1 diagnosis and the gold standard was now considered substantial (κ = 0.808). Meanwhile, examiner 2 made 43 correct diagnosis (85%), and the coefficient of agreement increased to κ = 0.883.
Table 3: Agreement between the examiner 1 and the gold standard biopsy report

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Table 4: Agreement between the examiner 2 and the gold standard biopsy report

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[Table 5] shows agreement between the clinical examination with gold standard biopsy report. Clinical examination was made by a single examiner. Clinical examiner made the correct diagnosis in 44 cases (86%), and the agreement between the clinical examiner and the gold standard was also considered good (κ = 0.919)
Table 5: Agreement between the clinical examination and the gold standard biopsy report

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  Discussion Top

Although the use of telemedicine has been studied in many medical specialties, there is a lack of consistent evidence for its advantages in dentistry. This study was conducted to evaluate the applicability of teledentistry in oral diseases by transmitting digital images through photographic methods.

The majority of studies in dental literature were developed using store-and-forward methodologies, perhaps because these methods are the cheaper and demand fewer resources than video conferencing. This study was also conducted using the store-and-forward method.

This study revealed that two distant examiners, examined the oral lesions by photographic examination method and gave two different diagnoses. The intraexaminer reliability for two examiners was 0.921 and 0.943, respectively. A similar study done by Mariño et al. also foundthat the intra-examiner agreements for dental examination by photographic methods determined by the Kappa index reflected an “Excellent” agreement (κ = 0.83).[24]

The level of inter-examiner agreement between examiner 1 and examiner 2 was 0.882 (Strong).

Agreement between the diagnosis made by the clinical examination and photographic methods was calculated. Intraclass correlation value between this method was 0.812. Similar studies done by Haron et al.,[25] Kopycka-Kedzierawski et al.,[19] Mariño et al.[26] found that the concordance between diagnoses based on clinical examination and teledentistry was moderate-to-strong (0.500–0.875).

This study revealed that both the examiners made the correct diagnosis in 41 (81%) cases and 43 (84%) cases, respectively. The possibility of giving two different diagnosis for each case increased the possibility of correct diagnosis, as expected. A similar study done by Torres-Pereira et al.[17] in the year of 2008 stated that 88% of total cases, at least one consultant provided the correct diagnosis. Also, Massone et al.[22] in the year of 2007 reported correct diagnoses of 74% of cases, compared with the telemedicine diagnosis and to the histopathological diagnosis in dermatology.

A key advantage of using the intra-oral photographic method is the capability to archive the images generated. This capability can give rise to some benefits, using information and communication technologies, archived intra-oral photographs can be used to provide remote training and calibration for individual or groups of examiners. Archiving would also allow remote assessment and scoring of intra-oral photographs in epidemiological studies that may require blinding. Improvement in intra-examiner reliability of remote examiner(s) and the sensitivity of the method could be explored by including random “pop up” test intra-oral photographs, which allows comparison with reference standard set of scores in which the examiner must achieve a set kappa level to be allowed to carry on with the assessment.

However, practicality issues regarding obtaining the intra-oral photographs that should be considered. Maintaining moisture control in the intraoral photograph was obtained to be difficult. This contributed to the increase in the time taken to obtain the intraoral photographs. The additional time, the costs versus the benefits of intra-oral photograph method needs to be assessed.

  Conclusion Top

Based on this study results, the smartphone camera use offers a valid and reliable means of remote screening for oral lesions. Despite limited research evidence on the use of a smartphone camera in the dental screening of oral lesions, the present study findings strengthened our previous reports that the mobile teledentistry approach has the potential to screen the oral lesions through the photograph taken by a smartphone with acceptable diagnostic validity and reliability.

Further based on this study results, it would be possible to state that there were no clinically significant differences between the photographic scores and the face-to-face assessments. The photographic approach was, therefore, equivalent in diagnostic utility to the visual system of diagnosis and confers considerable advantages in terms of remote scoring and archiving. These advantages must be weighed against the (modest) costs of the cameras but not the increased time required to acquire the images.


  1. Dental professionals should be motivated to take clinical photographs of pathological oral lesions routinely (with the patient's consent) as this will enhances both the quality of referrals and patient clinical records alike
  2. Research aimed at examining the potential of using clinical photography communicated by a teledentistry system as an alternative to the face-to-face examination should be undertaken.


The authors convey their sincere regards to the staffs and management of Thirumalai mission hospital for helping in the successful completion of the study. Furthermore, we would like to thank the Department of Oral and Maxillofacial pathology of Ragas dental college and Hospital for their contribution through timely rendering and biopsy reports.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]

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