Potential of Digital Approaches in Evaluating Rodent Caries

Abstract

Introduction:

This study aimed to assess the sensitivity, specificity, and accuracy of a digital-based method for caries assessment in a rodent model, compared to a conventional modified-Keyes method.

Methods:

108 mandible molars of Sprague Dawley rats were collected from a cariogenic caries rodent model, including both caries-free and carious teeth. Smooth surfaces were evaluated using digital photography, whereas sulcal lesions and volumetric quantification were assessed with micro-CT and the Amira software. In the conventional assessment, smooth surfaces were examined under a stereomicroscope with tactile probing, and sulcal surfaces were evaluated on stained, sectioned teeth. Sensitivity, specificity, and accuracy of the digital approaches were calculated, with the conventional method serving as the gold standard. Spearman correlation analysis was conducted between conventional enamel caries scores, combined digital (photography and micro-CT) enamel caries scores, and micro-CT quantified remaining enamel volume.

Results:

A total of 107 molars were available for smooth surfaces evaluation, and 98 molars were included for sulcal surfaces, tooth-level caries detection and enamel lesion assessments. For smooth surfaces, the digital photographic method demonstrated an accuracy of 88.0%, with a sensitivity of 88.8% and a specificity of 85.7%. In the evaluation of sulcal caries, Micro-CT analysis achieved an accuracy of 96.9%, with 100% sensitivity and 87.0% specificity. For tooth-level caries detection, the combined digital approaches of smooth surface photography and sulcal micro-CT slicing achieved 96.9% accuracy, 97.6% sensitivity, and 92.9% specificity.

Conclusions:

This study demonstrates the efficacy of digital photography and micro-CT in the caries assessment of rodent models. The findings support the establishment of a standardized, non-destructive imaging protocol to enhance consistency in caries research.

Introduction

Dental caries remains a prevalent chronic disease affecting populations worldwide, leading to significant health burdens and economic costs(1). The rodent model of dental caries has been instrumental in understanding the disease’s etiology, pathogenesis, and prevention(2). Traditionally, dental caries evaluation of rodent models has relied on time-consuming visual and tactile assessments. Among these, Larson’s modified Keyes method is widely regarded as the gold standard. Although well established and effective, this approach is inherently invasive, labor-intensive, and time-consuming, as it requires tooth sectioning, staining, and tactile examination(3).

With the advancement of digital technologies, alternative approaches for dental caries assessment have emerged that may address several limitations of the conventional methods. In particular, high-resolution digital photography and micro-computed tomography (micro-CT) are increasingly applied in dental research(4). Digital photography can provide detailed visual documentation of tooth surfaces, facilitating the identification of carious lesions(5). Micro-CT, on the other hand, provides three-dimensional visualization of dental tissues, allowing precise assessment of lesion depth and volume while preserving the integrity of the tooth structure(6). As a result, these techniques could offer non-destructive, high-resolution imaging capabilities that can enhance the detection and analysis of dental caries in rodent models. Moreover, digital workflows eliminate the need for strict time scheduling, sample sectioning, and staining, thereby improving overall efficiency and flexibility (Fig. 1).

Fig. 1.

Illustration of the conventional and digital workflows (as designed in this study) for caries evaluation in rodent models.

Diagram compares two rodent caries evaluation workflows. On the left, the Conventional workflow has five steps: (1) Sample preparation; (2) Evaluating smooth surfaces under a stereomicroscope with a strict time/evaluator schedule; (3) Sample section with risk of sample loss or damage; (4) Teeth staining; and (5) Evaluating sulcal surfaces under a stereomicroscope. On the right, the Digital workflow streamlines this into four steps: (1) Sample preparation; (2) Smooth surface digital record using DSLR photos; (3) Micro-CT scanning; and (4) Evaluating all surfaces using digital records on a flexible schedule, including DSLR photos for smooth surfaces, Micro-CT slicing for sulcal surfaces, and Micro-CT volume analysis.

Despite the potential advantages, there is limited evidence regarding the diagnostic performance of digitally based methods in rodent dental caries models, and no standardized digital workflow has been established. Therefore, this study aimed to assess the diagnostic performance of two digital imaging based approaches: 1) Digital single-lens reflex (DSLR) photography for evaluating smooth surface lesions, and 2) micro-CT, including sulcal surface evaluation through slicing and volumetric analysis with three-dimensional (3D) reconstruction and segmentation. In addition, the study sought to develop a standardized, non-invasive digital workflow to improve the consistency and reliability of caries assessment in rodent models.

Methods

Rodent caries model

A total of 36 mandibular jaws (18 left and 18 right) from 18 Sprague Dawley rats, comprising 108 molars (36 first, 36 second, and 36 third molars) were selected from previously conducted caries studies by a team member who was not involved in either the conventional or the digital evaluation approaches. Details of the cariogenic model have been described previously(7). Briefly, 12-day-old Sprague-Dawley rats were obtained with their dams from Charles River Laboratory. Pups were weaned at 19 days of age and provided ad libitum access to the National Institutes of Health cariogenic diet 2000 (TestDiet) and 5% sucrose water. Dental caries with various severities were induced with different inoculation protocols tested for the team’s previous studies, including blank control (no inoculation), Lactiplantibacillus plantarum (L. plantarum) colonization group, Streptococcus mutans (S. mutans) colonization group, Candida albicans (C. albicans) colonization group, S. mutans and C. albicans colonization group, L. plantarum precolonization before S. mutans and C. albicans colonization group, L. plantarum precolonization before S. mutans and C. albicans colonization group, and L. plantarum colonization before and after S. mutans and C. albicans colonization group. Inoculation procedure and timeline was detailed in supplementary material (Fig. S1). On day 47, the animals were euthanized using carbon dioxide asphyxiation. Teeth were cleaned of soft tissue debris and stored in phosphate-buffered saline at 4°C until analysis. Caries conditions were evaluated with Larson’s modified-Keyes method by a calibrated examiner.

Caries scoring with conventional approach

In the conventional assessment, the detection and scoring of lesions was recorded according to Larson’s modified Keyes method(8). Briefly, caries on smooth surfaces (the sum of buccal, lingual, and proximal surfaces) were visually assessed under stereomicroscope by counting the linear extension units of the lesion on each tooth. Lesions were graded into four categories based on depth: 1) E, enamel lesion (white, opaque enamel); 2)Ds, slight dentinal lesion (surface enamel is dry and crumbly in appearance); 3) Dm, moderate dentinal lesion (the dentine is exposed); 4) Dx, extensive dentinal lesion (The dentin is soft or missing and may be dark in color). Tactile probing was conducted using a blunt dental explorer to detect surface discontinuities and softening of the enamel or dentin. The molars were then sectioned sagittally in the mesiodistal direction through the central fissures and stained with a caries-indicating dye 0.4% ammonium purpurate to visualize lesion penetration. The sulcal areas were scored based on depth: 1) E, enamel lesion (dye penetration within enamel); 2) Ds, slight dentinal lesion (dye reaches dento-enamel junction, penetrating up to 1/3 of dentin depth); 3) Dm, moderate dentinal lesion (dye extends beyond 1/3 of dentin depth); 4) Dx, extensive dentinal lesion (dye penetrates through the entire dentin layer, which may be soft or missing). In the analysis process, the conventional approach served as the gold standard for evaluating diagnostic performance of the digital approaches (photography and micro-CT).

DSLR photography for smooth surface caries assessment

To ensure comparability, the scoring of carious lesions via digital approaches was standardized against the criteria of the conventional method. The calibrated examiner evaluating the digital data was blinded to the results of the conventional approach.

Prior to sectioning, each tooth was photographed using a Nikon D7500 DSLR camera equipped with a macro lens and ring flash to minimize shadowing and ensure uniform lighting. Mandibles were stabilized in plasticine to hold them securely and standardize exposure angles. Photographs were taken with the camera lens positioned perpendicular to the smooth surfaces, and caries scoring was performed by a calibrated examiner following the rules of Larson’s modified Keyes as mentioned in the conventional method. However, the scoring in the digital approach was based on visual examinations with digital pictures only.

Micro-CT for sulcal surface caries assessment and volumetric analysis

Digital evaluation of sulcal surface caries and whole-tooth 3D reconstruction were performed on mandibular teeth via micro-CT using a Scanco vivaCT 40 scanner with a 70-kVp source (Scanco). Jaws were scanned at a resolution of 10.5 μm isotropic voxels, with 300ms integration time. Images were reconstructed at identical thresholds (2,500 Hounsfield units [HU]) to allow a 3D structural rendering of each jaw. Caries evaluation was then performed using Amira software (v2022.2, Thermo Fisher Scientific), allowing 3D segmentation and visualization of lesion depth and volume.

In the analysis process, the central sagittal slice of each tooth obtained from the micro-CT scan, corresponding to the slice used in the conventional method, was used for direct comparison in sulcal surface caries scoring. 3D reconstruction, segmentation and volumetric quantification were conducted using established algorithms in the Amira software platform. Following automated segmentation of enamel and dentin, manual refinements were applied where necessary. The volumes of the remaining enamel and dentin were subsequently quantified. Detailed protocols for micro-CT scanning and the segmentation algorithms are provided in the supplementary material and a previously published article(7).

Statistical Analysis

All statistical tests were conducted with a two-sided significance level of 5%. Statistical analysis was performed using R, version 4.2.2 (R Foundation for Statistical Computing, Vienna, Australia). The mean average of tooth-level caries score was calculated to test the capability of digital approach evaluating different caries activities, jaws were also classified into low and high caries activity groups based on findings from a previous study by our team(7), which demonstrated distinct caries severities under different infection regimens. Mann-Whitney U test was used to compare the scores obtained between conventional and digital approaches. Based on caries lesion detection, binary data were generated and analyzed separately by surface type (smooth and sulcal surfaces), lesion severity (E, Ds, Dm, Dx), and at the tooth level following the integration of photographic and micro-CT results. The diagnostic performance of the digital approaches, including sensitivity, specificity, and accuracy, was evaluated against the conventional method as the gold standard. McNemar's Test was applied for statistical significance analysis.

For each tooth, a total enamel caries score was calculated by summing the smooth and sulcal surface scores obtained from either the conventional method or the combined digital approaches of photography (smooth surface) and micro-CT (sulcal surface). The relationships between these scores and the micro-CT quantified remaining enamel volume were evaluated using Spearman correlation analysis. However, Scoring of the dentinal lesions reflected by the modified Keyes scoring system was given based on three different severity categories (Ds, Dm, Dx), making merging the scoring difficult, thereofre, the direct comparision between the scores and 3D volume of the remianing dentin was not conducted in this study.

Results

In general, no significant differences were observed between the scores obtained using the conventional method and those derived from the digital appraoches for either smooth or sulcal surfaces (Table 1). The digital approaches of both photography (smooth surfaces) and micro-CT slicing (sulcal surafaces) performed comparably to the conventional method and effectively differentiated between low- and high-caries activity groups across multiple lesion categories. High-activity groups consistently exhibited markedly higher scores than low-activity groups.

Table 1.

Caries scores on smooth and sulcal surfaces across four lesion categories

	All			Low caries activity groups			High caries activity groups
Categories	Conventional	DSLR photo	p value	Conventional	DSLR photo	p value	Conventional	DSLR photo	p value
Smooth surface	(n=107 teeth)			(n=30 teeth)			(n= 77 teeth)
E	2.16 ± 2.01	2.68 ± 2.57	0.31	0.47 ± 0.86	0.40 ± 0.93	0.58	2.81 ± 1.95	3.55 ± 2.46	0.06
Ds	1.78 ± 1.92	1.81 ± 2.07	0.87	0.13 ± 0.57	0.17 ± 0.38	0.26	2.41 ± 1.88	2.44 ± 2.10	0.88
Dm	1.04 ± 1.48	1.09 ± 1.66	0.60	0.10 ± 0.40	0.00 ± 0.00	0.16	1.40 ± 1.59	1.51 ± 1.79	0.92
Dx	0.71 ± 1.30	0.52 ± 0.99	0.42	0.07 ± 0.25	0.00 ± 0.00	0.16	0.96 ± 1.45	0.72 ± 1.10	0.48
Categories	Conventional	Micro-CT	p value	Conventional	Micro-CT	p value	Conventional	Micro-CT	p value
Sulcal surface	(n=98 teeth)			(n= 24 teeth)			(n=74 teeth)
E	2.17 ± 1.68	2.54 ± 1.89	0.20	1.13 ± 1.20	1.46 ± 1.64	0.66	2.57 ± 1.67	2.88 ± 1.85	0.35
Ds	2.15 ± 1.68	2.49 ± 1.87	0.22	1.07 ± 1.11	1.38 ± 1.50	0.56	2.57 ± 1.67	2.85 ± 1.84	0.41
Dm	1.03 ± 1.22	0.99 ± 1.14	0.97	0.10 ± 0.31	0.21 ± 0.41	0.28	1.39 ± 1.26	1.24 ± 1.18	0.49
Dx	0.46 ± 0.80	0.28 ± 0.57	0.24	0.00 ± 0.00	0.00 ± 0.00	1.00	0.64 ± 0.89	0.37 ± 0.63	0.11

• All caries score values displayed in the format of Mean ± SD

• The classification into low and high caries activity groups was based on the findings of the previous study(8). Low caries activity group: blank control (no inoculation) and Lactiplantibacillus plantarum (L. plantarum) colonization group. High caries activity group: groups with caries induced inoculation, including Streptococcus mutans (S. mutans) colonization group, Candida albicans (C. albicans) colonization group, S. mutans and C. albicans colonization group, L. plantarum precolonization before S. mutans and C. albicans colonization group, L. plantarum precolonization before S. mutans and C. albicans colonization group, and L. plantarum colonization before and after S. mutans and C. albicans colonization group.

• E, enamel lesion; Ds, slight dentinal lesion; Dm, moderate dentinal lesion; Dx, extensive dentinal lesion

Smooth surfaces assessment with digital photography

Photographic assessment of smooth surface caries showed comparable performance with conventional method (n=107, one molar missing during the jaw dissection). Overall, the digital photographic method for detecting caries of smooth surfaces demonstrated an accuracy of 88.0%, with a sensitivity of 88.8% and a specificity of 85.7%. Regarding detecting four grades of caries, shown in Table 2, accuracy ranged from 87.0% to 89.8%. Specifically, sensitivity was generally high for detecting enamel (E), slight dentinal (Ds), and moderate dentinal (Dm) lesions, with sensitivity of 88.8%, 86.3%, and 89.6%, respectively. Although the sensitivity for detecting extensive dentinal lesions (Dx) was lower at 75.5%, this category exhibited the highest specificity at 96.6%. Overall, specificity remained consistently high across all lesion categories, ranging from 85.7% for enamel lesions (E) to 96.6% for extensive dentinal lesions (Dx).

Table 2.

Accuracy, sensitivity and specificity of photographic assessment of dental caries on smooth surfaces across four lesion categories

	Accuracy (n=107)	Sensitivity (n=107)	Specificity (n=107)	McNemar's Test (p-value)
E	88.0%	88.8%	85.7%	0.27
Ds	87.0%	86.3%	89.3%	0.06
Dm	89.8%	89.6%	90.2%	0.55
Dx	87.0%	75.5%	96.6%	0.01

E, enamel lesion; Ds, slight dentinal lesion; Dm, moderate dentinal lesion; Dx, extensive dentinal lesion

Sulcal surfaces assessment with micro-CT

9 teeth were lost during the sectioning and staining process of the conventional approach, resulting in a sample size of 98 for sulcal surface evaluation. Shown in Table 3, the micro-CT evaluation of sulcal caries demonstrated high diagnostic performance, with accuracy of 96.9%, 95.9%, 86.7%, and 90.8% for E, Ds, Dm and Dx lesions respectively. Sensitivity of 100% was achieved for enamel lesions, followed by Ds at 98.7%. Specificity of the digital approach for sulcal surface caries ranged from 84.8% (Dm) to 98.6% (Dx). Overall, micro-CT analysis achieved an accuracy of 96.9%, with a sensitivity of 100% and a specificity of 87.0% for sulcal caries detection.

Table 3.

Accuracy, sensitivity and specificity of micro-CT assessment of dental caries on sulcal surfaces across four lesion categories

	Accuracy (n=98)	Sensitivity (n=98)	Specificity (n=98)	McNemar's Test (p-value)
E	96.9%	100.0%	87.0%	0.25
Ds	95.9%	98.7%	87.0%	0.63
Dm	86.7%	88.5%	84.8%	1
Dx	90.8%	72.4%	98.6%	0.04

E, enamel lesion; Ds, slight dentinal lesion; Dm, moderate dentinal lesion; Dx, extensive dentinal lesion

Tooth-Level assessment with integrated digital approaches

At the tooth level, the combined use of digital photography (smooth surfaces) and micro-CT slicing (sulcal surfaces) for caries detection at the tooth level resulted in a sensitivity of 97.6%, specificity of 92.9%, and accuracy of 96.9%.

3D reconstruction and quantification of the teeth were conducted using the Amira software platform, enabling the visualization, segmentation, and volumetric measurement of the remaining enamel and dentin tissues (Fig. 2). Enamel caries scores from the combined digital approaches (photography and micro-CT) showed a strong positive Spearman correlation with those from the conventional method across smooth and sulcal surfaces (r=0.94, p<0.01). However, no significant correlation was found between the remaining enamel volume measured by micro-CT and the scores obtained from either the conventional or the combined digital approaches (Table 4).

Fig. 2.

Three dimensional micro-CT reconstructions for volumetric visualization of a rodent caries model, from an occlusal view.

(A) The remaining enamel volume of first, second and third molars (from right to left). The enamel was segmented and color-coded for each tooth to highlight morphological details. (B) The volumetric visualization of remaining dentin structure, from an occlusal view, revealing the internal configuration. (C) The combined visualization of enamel and dentin, allowing assessment of the spatial relationship between the two tissues. This integrated representation provides a comprehensive overview of structural preservation and tissue loss, serving as a useful tool in evaluating caries progression.

Table 4.

Spearman correlation of conventional scores, combined digital (photos and micro-CT) scores, and micro-CT volume analysis for enamel lesions

(n=98)	Conventional score (enamel)	Combined digital score (enamel)	Micro-CT remaining volume (enamel)
Conventional score (enamel)	1
Combined digital score (enamel)	0.94* (p<0.001)	1
Micro-CT remaining volume (enamel)	−0.08 (p=0.55)	0.03 (p=0.84)	1

^*p<0.01

Discussion

Overall, caries scores obtained using the digital approaches (photography and micro-CT), similar to those derived from the conventional method, effectively differentiated between the low- and high-caries activity groups across multiple lesion severity categories. The photographic assessment of dental caries on smooth surfaces demonstrated generally high sensitivity, specificity, and accuracy across all lesion categories from enamel to severe dentinal lesions, with the highest diagnostic performance for moderate dentinal lesions (Dm). Strong diagnostic capabilities were also noted for enamel (E) and slight dentinal (Ds) lesions, with both sensitivity and specificity reaching around 90%. However, for extensive dentinal lesion (Dx), although the specificity of the digital photographic method remained high at 96.6%, the sensitivity decreased to 75.5%. One possible explanation for the reduced sensitivity in detecting severe lesions is the inherent limitation of digital photographs, which lack the tactile feedback provided by explorers in the conventional approach (Fig. 3). This discrepancy highlights the potential limitation of digital methods, which rely exclusively on visual cues and therefore may underestimate lesion severity due to the absence of tactile input. Alternatively, iatrogenic damage to the enamel surface during probing in the conventional approach could also contribute to discrepancies in lesion classification(9). Collectively, findings from this and prior studies highlight the effectiveness of the photographic approach in evaluating early to moderate dental caries lesions. However, caution is warranted, and supplementary diagnostic tools should be considered when assessing extensive caries lesions on smooth surfaces.

Fig. 3.

Representative photograph of a rodent first molar exhibiting visible surface alterations.

The arrow highlights a site on the buccal surface of the first molar, where a severe carious lesion of score 1 (Dx, the dentin is soft or missing and may be dark in color) was identified using the conventional diagnostic method, which incorporates tactile feedback via an explorer. In contrast, digital photographic evaluation classified the same lesion as moderate of score 1 (Dm, the dentine is exposed), and score 0 was assigned to Dx. This example illustrates the diagnostic challenges inherent to smooth surface caries assessment and emphasizes the need for careful consideration of methodological differences in diagnostic approaches.

Regarding the sulcal surfaces, micro-CT slicing assessment was especially effective in detecting early enamel and slight dentinal lesions. Accuracy was highest for digitally detecting enamel (96.9%) and slight dentinal (95.9%) lesions, followed by moderate and extensive dentinal lesions, with accuracies of 86.7% and 90.8%, respectively. The digital method maintained an excellent specificity of 98.6%, however, the sensitivity was moderate at 72.4%. Similarly, a recent systematic review found that in dental caries diagnosis, micro-CT demonstrated good to excellent specificity in identifying true negatives, whereas the sensitivity values varied widely, ranging from poor to excellent(10). Compared to non-destructive micro-CT observation, conventional caries scoring usually involves tactile probing, sectioning, and staining. Artifacts may arise from the staining process. For example, dye can diffuse along micro-cracks or preparation defects, creating areas of discoloration that resemble carious lesions but do not represent true demineralization (Fig. 4). Additionally, it is technically sensitive to section the teeth along a central axis passing through the first to third molars in the conventional method. Failure to achieve precise midline sectioning may result in misestimation of lesion severity. There is also a risk of tooth loss during the sectioning process, particularly for the third molars. Previous reports have also indicated that sectioning may result in material loss ranging from 20 to 250 μm per slice(10). This mechanical loss can also artificially enlarge fissures or lesion areas, leading to overestimation of caries severity. Collectively, discrepancies between digital and conventional approaches may be attributed to the limitations of conventional method, including tissue loss during sectioning and the presence of artifacts with staining. Furthermore, a limitation of the conventional sulcal scoring approach can only be based on a single two-dimensional plane, whereas micro-CT allows for three-dimensional and multi-plane analysis.

Fig. 4.

Comparative evaluation of sulcal caries using conventional histological sectioning and micro-CT.

The four images from the same molar tooth. (A) The conventional approach. The first molar was sectioned from the mid-saggital plane and stained. The arrow highlights an extensive dentinal lesion (Dx, dye penetrates through the entire dentin layer) scored 2 on the buccal distal sulcus surface. (B-D) Different sagittal slices obtained from micro-CT of the same first molar, illustrating the non-destructive visualization and quantitative potential of this digital method. (B) The selected sagittal slice reflects the deepest lesion extension of the distal sulcal lesion observed among slices of the micro-CT. Indicated by the arrow, the lesion exhibits similar morphology to the conventional section, but without involvement of the pulp horn. (C) Sagittal central slice of the first molar. The arrow shows the distal sulcal lesion, score 2 of Dm (lesion extends beyond 1/3 of dentin depth, while not penetrates through the entire dentin layer) was assigned to the distal sulcus surface, and score 0 was for Dx. (D) The selected sagittal slice showing the deepest extension of the mesial sulcal carious lesion, as the arrow points. Collectively, these images underscore the capacity of micro-CT to provide high-resolution, three-dimensional insights into caries extension while preserving the integrity of the specimen.

The validity of the integrated digital (photography and micro-CT) approach for toot-level caries detection is demonstrated by its high diagnostic performance of accuracy, sensitivity, and specificity. Its efficacy is further supported by a strong Spearman correlation between conventional and integrated digital enamel caries scores. However, no significant correlation was observed between the remaining enamel volume and caries scores from either conventional or the integrated digital approach. This result indicates that the remaining volume, while useful as a visual reference, may not serve as a reliable indicator of caries severity assessment unless the baseline volume (before dental caries development) is available and the volume of structure loss can be calculated. Furthermore, dentinal lesions were classified into three distinct severity levels (Ds, Dm, Dx) rather than a single category, making it difficult to directly compare dentinal scoring with segmented dentinal volume or measured lesion depth. Nevertheless, there is no doubt that micro-CT offers significant promise for volumetric analysis while preserving the physical integrity of specimens(11, 12).

This study has several limitations. The moderate sensitivity observed in detecting extensive dentinal lesions on smooth surfaces suggests that adjunctive tactile examination may still be necessary for accurate severity assessment. In addition, future research is encouraged to explore integrating advanced technologies, such as artificial intelligence (AI), with micro-CT to improve the accuracy and efficiency of cavity detection and severity assessment. Furthermore, future studies including multiple examiners and reliability testing on the digital method are warranted. Overall, digital methods offer the potential for efficient, effective, high-resolution and three-dimensional analysis. which can facilitate the identification of subtle changes in lesion depth and progression. Such advancements could significantly enhance the utility of digital tools in dentistry, allowing for a more consistent and standardized approach in dental research and clinical diagnostics.

In conclusion, results in this study suggest that the digital approach involving DSLR imaging and micro-CT yield highly accurate outcomes and represent a non-invasive alternative for caries detection across different tooth surfaces and lesion severities. A simplified digital workflow of dental caries in rodent models was proposed in this study (Fig. 5). Integrating digital approaches into caries evaluation has the potential to enhance efficiency, reduce subjectivity, and provide more quantitative and comprehensive data for analysis. Future studies is encouraged to explore the feasibility of using digital approaches for longitudinal monitoring of caries progression in live rodent models.

Fig. 5.

Digital workflow for caries scoring and evaluation in rodent models.

Diagram shows a four-step digital workflow for rodent caries evaluation. (1) Sample preparation: collect jaws and remove soft tissues, illustrated with photos of the upper jaw, lower left jaw, and lower right jaw; (2) Smooth surface digital record (DSLR photos): photos of buccal, lingual, and occlusal tooth surfaces; (3) Micro-CT scanning: micro-CT image of a tooth cross-section with guidance to capture a screenshot of the central sagittal slice for each tooth. (4) Evaluating all surfaces with digital records: a caries scoring diagram and 3D tooth models, with notes to perform caries scoring using Larson’s modified Keyes method with digital photos and micro-CT slices, and to use 3D modeling software to detect and calculate lesion volume for quantitative analysis.

Data Availability Statement

All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.