Detection of Early Smooth Surface Caries in Primary Molars using Conventional Methods in a Low-Resource Setting: A Cross-sectional Study

1. Postgraduate Trainee, Department of Pedodontics, Dr. R. Ahmed Dental College and Hospital, Kolkata, West Bengal, India. 2. Associate Professor, Department of Pedodontics, Dr. R. Ahmed Dental College and Hospital, Kolkata, West Bengal, India. 3. Assistant Professor, Department of Oral Medicine and Radiology, North Bengal Dental College and Hospital, Siliguri, West Bengal, India. (Orcid- 0000-0003-2131-1126) 4. Associate Professor, Department of Dentistry, Burdwan Medical College and Hospital, Burdwan, West Bengal, India.

Abstract

Introduction: Dental caries is a widespread chronic disease that affects nearly 100% of adults in developing countries. Detecting caries early is crucial for effective remineralisation and improved prognosis. However, identifying smooth surface caries in its early stages remains challenging for many healthcare professionals globally due to the subjective nature of visual inspection.

Aim: To determine the most effective method for detecting early smooth surface caries in limited resource settings.

Materials and Methods:The present cross-sectional study was conducted in the Department of Pedodontics, Dr. R. Ahmed Dental College and Hospital (tertiary care centre), Kolkata, West Bengal, India, from March 2021 to August 2022. Study was conducted involving 120 primary molars from Bengali children aged 5 years and above. The teeth were randomly selected while adhering to specific inclusion and exclusion criteria. The occlusal and proximal surfaces of the teeth were assessed using three methods: unaided Visual Examination (VE), Magnifying Loupe (ML)-assisted VE, and the fluorescence-based DIAGNOdent pen (considered the gold standard). Two assessments were performed for each method, one before air-drying and another after air-drying. Caries detection followed the International Caries Detection and Assessment System (ICDAS) II clinical scoring system, and data analysis was conducted using the Chi-square test for proportions.

Results: In the present study, there were 76 male children and 44 female children and the mean age of the children was 7±2.5 years. Unaided VE exhibited a diagnostic accuracy of 87.5% and 77.5% for air-dried and non air-dried tooth surfaces, respectively. ML-aided VE yielded a diagnostic accuracy of 88.34% and 85% for air-dried and non air-dried tooth surfaces, respectively.

Conclusion: The present study concluded that even without the assistance of an ML, drying the tooth surface can achieve a level of caries detection accuracy comparable to that of ML-aided VE.

DIAGNOdent, Diagnostic accuracy, Magnifying loupes, Smooth surface caries

Dental caries is a prevalent issue affecting a significant portion of school-aged children in most developed nations, with rates ranging from 60-90%. Among adults, the prevalence is even higher, affecting nearly the entire population in many countries. This disease involves a continuous process of demineralisation and remineralisation. However, interventions can be implemented to halt or reverse its progression (1).

Over the last three decades, there have been notable changes in the way this disease manifests. Enamel caries now progresses more slowly, allowing for preventive measures before irreversible damage occurs (2). In its early stages, the caries process is reversible, and non invasive interventions can transition an active lesion to an inactive state (3),(4).

Detecting caries early is crucial for preventing and treating lesions (5). Occlusal surfaces are particularly susceptible to caries in both children and adults due to the unique morphology of pits and fissures, making plaque removal challenging. Therefore, the significance of early caries detection has grown considerably in recent years (6),(7).

To achieve early caries detection, effective diagnostic techniques are essential. Implementing strategies to arrest or reverse the disease process can alleviate the economic burden, pain and suffering associated with the placement and replacement of restorations (8). Augmenting traditional diagnostic methods with more sensitive and advanced techniques can enhance caries diagnostic procedures and improve dental care and patient treatment. Such complementary methods should provide objective information about lesion presence and severity, supplementing the clinician’s subjective assessment and promoting evidence-based clinical caries diagnosis (9),(10).

Traditional caries examination relies heavily on subjective interpretation during VE. Clinicians make dichotomous decisions based on their subjective assessment of colour, texture, and location using relatively basic instruments like dental mirrors, explorers and bitewing radiographs (11). Visual aids, such as low-powered magnification (dental loupes), have gained popularity among dentists to enhance VE precision and ergonomics. However, detecting non cavitated lesions and microcavities in enamel remains challenging, and inconsistencies in diagnosis can lead to treatment variations (12). While this method offers high specificity, its sensitivity is relatively low (13).

To overcome these limitations, a fluorescence-based approach utilising a diode laser fluorescence device, known as DIAGNOdent (KaVo, Charlotte, NC), was introduced. DIAGNOdent employs a diode laser emitting red light (655 nm), which is absorbed by bacterial by-products like porphyrins. This light is partially re-emitted as near-infrared fluorescence. The device captures and translates this fluorescence into a numerical scale ranging from 0 to 99, where higher values indicate deeper caries lesions (14),(15).

Initially, DIAGNOdent was designed to detect caries on occlusal and smooth surfaces only and did not cater to proximal caries detection, requiring radiographs for assessment (16). To address this limitation, a new version, the DIAGNOdent pen, was developed, enabling assessment of both occlusal and proximal surfaces (17). The device operates on the same principles as the previous version but features a tip that can rotate around its axis, facilitating the evaluation of proximal surfaces from both buccal and lingual perspectives.

In resource-limited settings, the detection of early caries in primary molars primarily relies on VE and ML, considered conventional methods. In the present study, the authors explored the detection of early smooth surface carious lesions in primary molars using three different methods: VE, ML (conventional), and DIAGNOdent (gold standard). The present study aimed to compare these methods to determine the most effective conventional approach for early caries detection and also evaluated the efficacy of each method both before and after air-drying the tooth surfaces.

Material and Methods

The present cross-sectional study was conducted in the Department of Pedodontics, Dr. R. Ahmed Dental College and Hospital (tertiary care centre), Kolkata, West Bengal, India, from March 2021 to August 2022. The study received clearance from the Institutional Ethical Committee (DCH/2021/38).

Inclusion criteria: Children who had completed their full immunisation schedule, children aged 5 years and above with non cavitated, visually intact primary molars that exhibited no evidence of developmental defects or hypoplasia were included in the study.

Exclusion criteria: Primary molars with cavities, restorations, pulpal involvement, or dental anomalies were excluded from the study.

Sample size calculation: To determine the required sample size, G*Power software was employed using the following parameters:

1. Analysis type: A priori.
2. Test family: F tests.
3. Statistical test: Analysis of Variance (ANOVA): Repeated measures, between factors.
4. Input:

• Effect size: 0.25 (18).
• α error probability: 0.05.
• Power (1-β) error probability: 0.8.
• Number of groups: 3.
• Number of measurements: 2.
• Correlation among repeated measures: 0.5.

The output yielded a total sample size of 120, to achieve 80.4% power at a 95% confidence level. No control group was necessary for the present study. The 120 primary molars were randomly selected based on the inclusion and exclusion criteria from the five years and above age group.

Study Procedure

After obtaining informed consent from the guardians, a comprehensive examination was conducted, and the children’s ages were recorded. Thorough oral prophylaxis was performed before readings were taken.

The occlusal surfaces (n=103) and proximal surfaces (n=39) of all primary molars were assessed using the naked eye for VE, ML-aided VE (Endo-King Dental loupes with frame 2.5x-3.5x), and DIAGNOdent pen (DIAGNOdentTM pen 2190). Each test was conducted twice on the same tooth, both before and after air-drying (Table/Fig 1),(Table/Fig 2),(Table/Fig 3).

Unaided VE and ML-aided VE were carried out with the child seated in the dental chair, observing the suspect tooth from a standardised operating distance. The DIAGNOdent pen was recalibrated with the selected tip, and suspicious sites on the primary molars were examined with the handpiece’s tip lightly contacting the tooth surface, moved in a pendulum-like manner. Three readings were obtained, and the highest one was considered. DIAGNOdent fluorescence readings were between 0-99, with sound teeth and non cavitated initial enamel lesions being scored as 1 and 2/3, respectively. DIAGNOdent categorical scores were as follows:

Score 1: 0-4 (healthy tooth structure).
Score 2: 5-10 (outer half enamel caries).

Scoring criteria for VE, ML-aided VE and DIAGNOdent pen followed the ICDAS II criteria (Table/Fig 4) (21). The result from the DIAGNOdent pen was considered the gold standard.

Statistical Analysis

Data collected were tabulated in Microsoft Excel 2019 software and analysed using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) Statistics for Windows, software version 26.0. Graphs, box plots, and pie diagrams were created using GraphPad Prism for Windows, software version 9.0. Normality tests revealed skewed data, prompting the use of non-parametric tests for inferential statistics. The Chi-square test was used for categorical variables. Intragroup and intergroup comparisons were performed using the Wilcoxon’s signed-rank test and Friedman’s ANOVA, followed by Dunn’s test. A significance level of 0.05 was considered statistically significant.

Results

In the present study, the children had a mean age of 7±2.5 years. Among the participants, there was a male predominance, with 76 children being males and 44 being females, resulting in a male-to-female ratio of 1.7:1.

For all three methods of caries detection (VE, ML and DIAGNOdent pen), the ability to detect smooth surface carious lesions was significantly more efficient and accurate when the tooth surface was air-dried compared to when it was not (p-value <0.001), as shown in (Table/Fig 5). In both situations, with and without air-drying, the DIAGNOdent pen exhibited the highest accuracy in smooth surface caries detection, followed by ML, and lastly VE, with a p-value of <0.05 for all three groups.

There was a significant difference between each of the three methods, namely VE, ML-aided VE, and DIAGNOdent pen, in both air-dried (p-value=0.0016) and non air-dried scenarios (p-value=0.0011) (Table/Fig 6). There were no significant differences in caries detection between VE and ML-aided VE in non air-dried primary molars (p-value=0.24). However, significant differences were observed between VE and DIAGNOdent, and between ML and DIAGNOdent in caries detection for both air-dried and non air-dried tooth surfaces (p-value <0.001) (Table/Fig 7). The ML with air-drying demonstrated the highest diagnostic accuracy of 88.34%, closely followed by VE with air-drying at 87.5%. Without air-drying, the diagnostic validity of both VE and ML decreased and was recorded at 77.5% and 85%, respectively (Table/Fig 8).

Discussion

The present study demonstrated that all three methods exhibited significantly higher efficiency and accuracy when the tooth surface was air-dried compared to non air-dried surfaces. This suggests that using air-drying as a standard procedure during examination can enhance the diagnostic accuracy of all three methods.

In both air-dried and non air-dried scenarios, the DIAGNOdent pen outperformed the other two methods, VE and ML, in terms of accuracy, establishing it as the gold standard in the present study. This reinforces the notion that fluorescence-based diagnostic tools can offer more reliable results, particularly in the detection of early carious lesions. The DIAGNOdent pen’s ability to quantify fluorescence and provide a numerical scale for caries severity enables a more objective assessment compared to the subjective judgments involved in VEs. Consequently, this can facilitate evidence based clinical decision-making (22).

Magnifying loupes have gained popularity among dentists as they improve the precision of VE and offer ergonomic advantages. However, the present study indicated that while MLs can enhance VE, they did not surpass the accuracy of the DIAGNOdent pen. The data showed that MLs had intermediate sensitivity and specificity compared to unaided VE and the DIAGNOdent pen. This suggests that while MLs provide benefits, they may not be as effective as fluorescence-based tools for early caries detection (23).

The impact of air-drying on detection accuracy is noteworthy. Both unaided VE and ML-aided VE demonstrated significantly higher accuracy when the tooth surface was air-dried. This implies that ensuring a dry tooth surface is a crucial aspect of the examination process. In resource-limited settings where advanced tools may not be readily available, this finding highlights the importance of basic techniques like air-drying to improve diagnostic accuracy (19).

When using the ICDAS II criteria with air-drying, VE exhibited a sensitivity of 93.2% and a diagnostic accuracy of 87.5%. In contrast, without air-drying, the sensitivity and diagnostic accuracy were 78.5% and 77.5%, respectively. This underscores the significant impact of air-drying in increasing both sensitivity and diagnostic accuracy. Similar studies by Braga MM et al., and Diniz MB et al., have confirmed the reliability of VE for detecting early smooth surface caries in primary molars using the ICDAS II criteria (24),(25).

The effectiveness of air-drying in caries detection is attributed to the fact that saliva can obstruct the pores in both cavitated and non cavitated carious teeth. This obstruction can mask differences in light reflection between carious and healthy tooth structures, making it challenging to observe changes in enamel surface colour and brightness. In contrast, dry teeth exhibit white spots more visibly due to differences in refractive indices between enamel, water and air (2),(11).

The diagnostic validity of ML with air-drying, using the ICDAS II criteria, demonstrated a sensitivity of 97.7% and a diagnostic accuracy of 88.34%. This suggests that while ML did not show a statistically significant difference compared to unaided VE, it slightly enhanced sensitivity, which aligns with a study by Mitropoulos P et al., (26).

Teo TKY et al., also reported that low-powered magnification significantly improved sensitivity for occlusal and proximal caries compared to unenhanced VE (27). When ML was used without air-drying, the sensitivity and specificity were 94.9% and 65.9%, respectively, indicating the beneficial impact of air-drying on caries detection.

After air-drying, VE aided by ML demonstrated a slight advantage over unaided VE in caries detection, with diagnostic accuracy of 88.34% and 87.5%, respectively. Without air-drying, the accuracy was 85% and 77.5%, respectively. Air-drying significantly improved the visibility of smooth surface early carious lesions in primary molars during both unaided VE and ML-guided VE.

Gupta N et al., also supported the effectiveness of VE-aided ML with air-drying for the detection of smooth surface caries in primary molars (28). When the tooth surface was air-dried, both aided and unaided VE were almost equally efficient in caries detection. However, without air-drying, there was a notable difference in the diagnostic accuracy of smooth surface caries detection between aided and unaided VE. Similar studies have been compared in (Table/Fig 9) (24),(25),(26),(27),(28).

These findings have practical implications for dental practitioners working in limited resource settings. The study suggests that in such environments, unaided VE, when combined with air-drying, can be a viable option for detecting early smooth surface caries. Additionally, the results emphasise the utility of the DIAGNOdent pen when available, given its superior accuracy.

While the present study provides valuable insights, further research is warranted to explore additional factors that may influence the diagnostic accuracy of these methods. Factors such as operator experience, equipment calibration, and variations in tooth morphology could impact the results. However, it is worth noting that some researchers have observed that DIAGNOdent may have a tendency to over-score, which could potentially influence the study results (29). Additionally, long-term follow-up studies are needed to assess the actual clinical outcomes of different diagnostic methods in terms of treatment planning and patient management.

Limitation(s)

The present study utilised DIAGNOdent as the gold standard for caries detection, comparing with histopathological evaluation might have given more accurate results.

Conclusion

The diagnostic accuracy of ML with air-drying showed the maximum diagnostic accuracy of 88.34%, followed by VE with air-drying at 87.5%. Drying the tooth surface can bring the diagnostic accuracy of unaided VE at par with that of ML-aided VE. Therefore, it is recommended that in resource constrained settings, when detecting smooth surface early caries (both occlusal and proximal), the tooth should be dried using any mechanical or automatic device, followed by unaided VE. In cases where air-drying tools are unavailable, the reliability of unaided VE is compromised, making ML-aided VE a recommended alternative. The present study emphasises the significance of early smooth surface caries detection, particularly in resource-limited settings, and highlights the effectiveness of basic techniques in improving diagnostic accuracy when advanced tools are not accessible.

DOI and Others

DOI: 10.7860/JCDR/2024/67006.18876

Date of Submission: Aug 12, 2023
Date of Peer Review: Oct 14, 2023
Date of Acceptance: Nov 20, 2023
Date of Publishing: Jan 01, 2024

AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. Yes

PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Aug 12, 2023
• Manual Googling: Oct 28, 2023
• iThenticate Software: Nov 17, 2023 (10%)

ETYMOLOGY: Author Origin

EMENDATIONS: 7