Assessing tooth wear progression in non-human primates: a longitudinal study using intraoral scanning technology.

Intraoral scanners are widely used in a clinical setting for orthodontic treatments and tooth restorations, and are also useful for assessing dental wear and pathology progression. In this study, we assess the utility of using an intraoral scanner and associated software for quantifying dental tissue loss in non-human primates. An upper and lower second molar for 31 captive hamadryas baboons (Papio hamadryas) were assessed for dental tissue loss progression, giving a total sample of 62 teeth. The animals are part of the Southwest National Primate Research Center and were all fed the same monkey-chow diet over their lifetimes. Two molds of each dentition were taken at either two- or three-year intervals, and the associated casts scanned using an intraoral scanner (Medit i700). Tissue loss was calculated in WearCompare by superimposition of the two scans followed by subtraction analysis. Four individuals had dental caries, and were assessed separately. The results demonstrate the reliability of these techniques in capturing tissue loss data, evidenced by the alignment consistency between scans, lack of erroneous tissue gain between scans, and uniformity of tissue loss patterns among individuals (e.g., functional cusps showing the highest degree of wear). The average loss per mm2 per year for all samples combined was 0.05 mm3 (0.04 mm3 for females and 0.08 mm3 for males). There was no significant difference in wear progression between upper and lower molars. Substantial variation in the amount of tissue loss among individuals was found, despite their uniform diet. These findings foster multiple avenues for future research, including the exploration of wear progression across dental crowns and arcades, correlation between different types of tissue loss (e.g., attrition, erosion, fractures, caries), interplay between tissue loss and microwear/topographic analysis, and the genetic underpinnings of tissue loss variation.

Diagnosis of dental caries based on attenuation coefficients analysis of optical coherence tomography images.

Quantitative analysis of optical attenuation based on optical coherence tomography images will offer an effective method to enhance diagnostic capabilities. In this paper, the optical attenuation in demineralized caries specimens was calculated to distinguish between normal teeth and carious teeth and further to differentiate the severity of caries, and thus come to the half-automated diagnosis of dental caries. Results show that the attenuation coefficient in carious regions is approximately 4.97 mm - 1 ± 0.206 , while that of normal teeth is about 3.69 mm - 1 ± 0.231 . Attenuation coefficient of carious regions is 35% higher than that of normal teeth. Moreover, five classes of caries were qualified and classified based on the optical attenuation coefficient. Compared with the healthy teeth, there is a noticeable disparity in the attenuation coefficients of carious teeth, both on the surface and at the dentinoenamel junction. This study provides a method for accurate caries diagnosis, particularly in detection of early lesions and subtle structural changes.

Fungi and bacteria occupy distinct spatial niches within carious dentin.

The role of bacteria in the etiology of dental caries is long established, while the role of fungi has only recently gained more attention. The microbial invasion of dentin in advanced caries especially merits additional research. We evaluated the fungal and bacterial community composition and spatial distribution within carious dentin. Amplicon 16S rRNA gene sequencing together with quantitative PCR was used to profile bacterial and fungal species in caries-free children (n = 43) and 4 stages of caries progression from children with severe early childhood caries (n = 32). Additionally, healthy (n = 10) and carious (n = 10) primary teeth were decalcified, sectioned, and stained with Grocott's methenamine silver, periodic acid Schiff (PAS) and calcofluor white (CW) for fungi. Immunolocalization was also performed using antibodies against fungal ß-D-glucan, gram-positive bacterial lipoteichoic acid, gram-negative endotoxin, Streptococcus mutans, and Candida albicans. We also performed field emission scanning electron microscopy (FESEM) to visualize fungi and bacteria within carious dentinal tubules. Bacterial communities observed included a high abundance of S. mutans and the Veillonella parvula group, as expected. There was a higher ratio of fungi to bacteria in dentin-involved lesions compared to less severe lesions with frequent preponderance of C. albicans, C. dubliniensis, and in one case C. tropicalis. Grocott's silver, PAS, CW and immunohistochemistry (IHC) demonstrated the presence of fungi within carious dentinal tubules. Multiplex IHC revealed that fungi, gram-negative, and gram-positive bacteria primarily occupied separate dentinal tubules, with rare instances of colocalization. Similar findings were observed with multiplex immunofluorescence using anti-S. mutans and anti-C. albicans antibodies. Electron microscopy showed monomorphic bacterial and fungal biofilms within distinct dentin tubules. We demonstrate a previously unrecognized phenomenon in which fungi and bacteria occupy distinct spatial niches within carious dentin and seldom co-colonize. The potential significance of this phenomenon in caries progression warrants further exploration.

3D intraoral scanning techniques support the effects of crown morphology on dental caries.

BACKGROUND: With the development and utilization of three-dimensional (3D) intraoral scanning (IOS) technology, the morphological characteristics of teeth were quantitatively assessed. In this research, we aimed to explore the prevalence of dental caries in relation to each measurable morphological indicator of the tooth body via 3D intraoral scanning techniques. METHODS: A hospital-based single-centre study was conducted at our hospital from Dec. 2021 to Apr. 2023. A total of 53 patients were involved in the study, providing complete morphological data for 79 teeth. Each patient completed an oral hygiene routine questionnaire and underwent examination by an experienced dentist to evaluate caries conditions before undergoing 3D intraoral scanning to obtain a digital dental model. Geomagic Studio 2014 was used to extract oral morphological data from the models. The acquired data were entered, cleaned and edited using Excel 2016 and subsequently exported to SPSS version 25.0 for analysis. Chi-square analysis and logistic regression analyses were employed to test the associations. RESULTS: Among the participants, 33 (61.1%) were female, with a mean age of 26.52 ± 10.83 years. Significant associations were found between dental caries and the vertical distance between the distal tip and the gum (OR 14.02; 95% CI 1.80-109.07; P = 0.012), the distal lateral horizontal distance of occlusion (OR 0.40; 95% CI 0.18-0.90; P = 0.026), and the mesial horizontal distance of occlusion (OR 2.20; 95% CI 1.12-4.31; P = 0.021). The Hosmer-Lemeshow test indicated a P value of 0.33. CONCLUSIONS: The vertical distance between the distal tip and the gum, the distal lateral horizontal distance of the occlusion and the mesial horizontal distance of the occlusion were the influencing factors for dental caries (identified as independent risk factors). We hypothesize that these factors may be associated with the physiological curvature of teeth and the role of chewing grooves in plaque formation over time. However, further studies involving larger population samples and more detailed age stratification are still needed.

Temporal pattern of dental caries at the western flank of the Central Plateau of Iran, c. 2700 BCE - 1600 CE.

OBJECTIVE: To analyze the overall frequency and inter-tooth patterns of caries in three populations from ancient cemeteries located along the western border of the Central Iranian Plateau as a means to explore whether the populations of Iran had greater access to fermentable sugars after the establishment of the great empires. MATERIALS: Dental collections from Kafarved-Varzaneh (Early Bronze Age, MNI=66), Estark-Joshaqan (Iron Age, MNI=57), Tappeh Poustchi (Timurid and Safavid Period, MNI=34), together with comparative data from NE Syria. METHODS: Frequencies of dental caries per tooth categories, location and size of carious lesions are analyzed using Smith's Mean Measure of Divergence, Correspondence Analysis, χ2 and Kruskal-Wallis tests. RESULTS: There are minimal differences in overall frequencies of carious lesions at Iranian sites, regardless of the chronology, but notable differences at Syrian sites. The inter-tooth pattern at the Iron Age cemetery in Estark appears distinctly different than the other Iranian sites and the comparative samples from Syria. CONCLUSIONS: Divergent subsistence strategies may be linked with different inter-tooth patterns since people buried at Estark were mobile herders, while the other cemeteries were used by settled farmers. SIGNIFICANCE: This comprehensive research on dental caries in three chronologically diverse populations in Iran sheds light on the association between dental caries and subsistence strategies, and introduces the Smith's Mean Measure of Divergence to explore inter-tooth carious patterns, which may prove useful to other researchers seeking to understand the relationships between subsistence, diet, and the presence of carious lesions. LIMITATIONS: The studied sample size is relatively small and therefore its temporal/regional distribution produces low-resolution results. SUGGESTIONS FOR FURTHER RESEARCH: More systematic research on the patterns of dental caries is necessary to produce more fine-grained reconstructions of diet and subsistence in Iran and around the globe.

Assessment of dental pulp response to carries via MR T2mapping and histological analysis.

OBJECTIVES: The aim of our study was to assess the correlation between T2 relaxation times and their variability with the histopathological results of the same teeth in relation to caries progression. MATERIALS AND METHODS: 52 extracted permanent premolars were included in the study. Prior to extractions, patients underwent magnetic resonance imaging (MRI) scanning and teeth were evaluated using ICDAS classification. Pulps of extracted teeth were histologically analysed. RESULTS: MRI T2 relaxation times (ms) were 111,9 ± 11.2 for ICDAS 0, 132.3 ± 18.5* for ICDAS 1, 124.6 ± 14.8 for ICDAS 2 and 112. 6 ± 18.2 for ICDAS 3 group (p = 0,013). A positive correlation was observed between MRI T2 relaxation times and macrophage and T lymphocyte density in healthy teeth. There was a positive correlation between vascular density and T2 relaxation times of dental pulp in teeth with ICDAS score 1. A negative correlation was found between T2 relaxation times and macrophage density. There was a positive correlation between T2 relaxation time variability and macrophage and T lymphocyte density in teeth with ICDAS score 2. In teeth with ICDAS score 3, a positive correlation between T2 relaxation times and T2 relaxation time variability and lymphocyte B density was found. CONCLUSION: The results of our study confirm the applicability of MRI in evaluation of the true condition of the pulp tissue. CLINICAL RELEVANCE: With the high correlation to histological validation, MRI method serves as a promising imaging implement in the field of general dentistry and endodontics.

Comparing the effectiveness of caries arrest by micro-operative treatment to operative treatment: A 2-year randomized controlled clinical trial.

OBJECTIVES: To compare the effectiveness of caries arrest by micro-operative treatment (sealing) to operative treatment (flowable resin composite restoration) through a 2-year randomized controlled clinical trial. MATERIALS AND METHODS: A prospective randomized controlled trial was conducted among 7-9-year-old children. At baseline, 630 subjects were screened and 92 children who had at least one carious lesion classified as ICDAS 3 on the pit and fissure of first permanent molar were included. Then they were randomly assigned to the sealant group (73 lesions) and the flowable resin composite group (76 lesions) to receive the corresponding intervention. Lesions status in each group was evaluated every 6 months up to 24 months. Clinical progression of dental caries and materials retention were the outcomes used for group comparisons at p-value < 0.05. RESULTS: After 24 months, three lesions (4.1%) in the sealant group clinically progressed to dentin caries. No lesion in the flowable composite group was observed a progression. The results of Life-table survival analysis show that the cumulative caries arrest rate had no statistically significant difference between the two groups (p = 0.075). However, the cumulative retention rate was 57.5% in the sealant group and 92.1% in the flowable composite group, with significant differences (p < 0.001). The multilevel mixed model showed the sealant had higher risk of retention failure than the flowable composite (OR = 8.66, p < 0.001), while tooth position did not influence material retention (p = 0.083). In addition, the results of Fisher Exact test show that dentin lesions had more retention failure than enamel lesions in the sealant group (p = 0.026). CONCLUSION: Although sealing microcavitated carious lesions of the first permanent molar achieved lower retention rate than resin composite restoration, both sealing and restoration effectively arrested caries progression for two years. CLINICAL RELEVANCE: To preserving dental structure and delaying or eliminating the need for operative procedures, microcavitated carious lesion can be arrested by sealing. TRIAL REGISTRATION: Registered at http://www.chictr.org.cn ; Feb 15th, 2020; No. ChiCTR2000029862.

AI-Dentify: deep learning for proximal caries detection on bitewing x-ray - HUNT4 Oral Health Study.

BACKGROUND: Dental caries diagnosis requires the manual inspection of diagnostic bitewing images of the patient, followed by a visual inspection and probing of the identified dental pieces with potential lesions. Yet the use of artificial intelligence, and in particular deep-learning, has the potential to aid in the diagnosis by providing a quick and informative analysis of the bitewing images. METHODS: A dataset of 13,887 bitewings from the HUNT4 Oral Health Study were annotated individually by six different experts, and used to train three different object detection deep-learning architectures: RetinaNet (ResNet50), YOLOv5 (M size), and EfficientDet (D0 and D1 sizes). A consensus dataset of 197 images, annotated jointly by the same six dental clinicians, was used for evaluation. A five-fold cross validation scheme was used to evaluate the performance of the AI models. RESULTS: The trained models show an increase in average precision and F1-score, and decrease of false negative rate, with respect to the dental clinicians. When compared against the dental clinicians, the YOLOv5 model shows the largest improvement, reporting 0.647 mean average precision, 0.548 mean F1-score, and 0.149 mean false negative rate. Whereas the best annotators on each of these metrics reported 0.299, 0.495, and 0.164 respectively. CONCLUSION: Deep-learning models have shown the potential to assist dental professionals in the diagnosis of caries. Yet, the task remains challenging due to the artifacts natural to the bitewing images.

The effect of combined use of resin infiltration with different bioactive calcium phosphate-based approaches on enamel white spot lesions: An in vitro study.

OBJECTIVES: This in vitro study aimed to evaluate the effect of resin infiltration combined with casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF) or bioactive glass (BAG) on the stability of enamel white spot lesions (WSLs) treatment. MATERIALS AND METHODS: Eighty-four enamel blocks were prepared from the buccal surfaces of sound human premolars. All enamel blocks were placed in a demineralisation solution for 3 days to establish the artificial enamel WSLs. Enamel blocks with WSLs were randomly divided into three groups (n = 28 each group): RI/B: one-off resin infiltration followed by twice daily BAG treatment; RI/C: one-off resin infiltration followed by twice daily CPP-ACPF treatment; RI: one-off resin infiltration treatment only (as control) and subjected to pH cycling for 7 days. Surface morphology, elemental analysis, crystal characteristics, surface roughness and microhardness of enamel surfaces were investigated by scanning electron microscopy and energy-dispersive spectrometry observation, X-ray diffraction (XRD), atomic force microscope and Vickers' hardness testing, respectively. RESULTS: Mean values of the surface roughness (mean±standard deviation (nm)) were 24.52±5.07, 27.39±5.87 and 34.36±4.55 for groups RI/B, RI/C and RI respectively (p = 0.003). The calcium to phosphate ratios were 1.32±0.16, 1.22±0.26 and 0.69±0.24 for groups RI/B, RI/C and RI respectively (p < 0.001). XRD revealed apatite formation in all three groups. The mean enamel surface microhardness (kg/mm2) of the groups were 353.93±28.49, 339.00±27.32 and 330.38±22.55 for groups RI/B, RI/C and RI respectively (p = 0.216). CONCLUSIONS: Resin infiltration combined with CPP-ACPF or BAG remineralisation appears to improve the surface properties of WSLs. CLINICAL SIGNIFICANCE: The combination of resin infiltration and CPP-ACPF/BAG remineralisation may be a potential treatment for the management of the WSLs.

Sixty-month comperative evaluation of a glass hybrid restorative and a composite resin in non-carious cervical lesions of bruxist individuals.

OBJECTIVE: To compare the clinical performance of a glass hybrid (GH) restorative and a nano-ceramic composite resin (CR) in the restoration of non-carious cervical lesions (NCCLs) of bruxist individuals in a 60-month randomized clinical trial. MATERIALS AND METHODS: Twenty-five bruxist candidates having NCCLs were recruited in this clinical study. The depth, height (cervico-incisal), width (mesio-distal), internal angles of the NCCLs, degree of tooth wear (TWI) and gingival index (GI) were measured. One hundred-and-forty-eight NCCLs were restored either with a GH restorative (Equia Forte Fil) or a CR (Ceram.X One Universal). Modified USPHS criteria was used to evaluate restorations after 1 week and 12, 24, 36 and 60 months. Pearson's Chi-Square, Fisher's Exact and Cochran Q tests were run for analysis. Survival rates of the restorations were compared with Kaplan-Meier analysis (p < 0.05). RESULTS: After 60 months, 97 restorations in 15 patients were examined. The recall rate was 60.0%. Retention rates were 73.5% for CR and 66.7% for GH. A total of 29 restorations were lost (13CR (26.5%), 16GH (33.3%)). There was not a significant difference between tested restoratives in retention (p = 0.464), marginal adaptation (p = 0.856) and marginal discoloration (p = 0.273). There was no relationship between internal angle, depth, height or width and retention of the GH or CR restorations (p > 0.05). The increase in retention loss and marginal discoloration of both restorations over time were significant (p < 0.001). Sensitivity or secondary caries were not detected after 60 months. CONCLUSION: GH and nano-ceramic CR showed similar clinical performances in NCCLs after 60 months in patients with bruxism. CLINICAL SIGNIFICANCE: After 60 months, CR and GH materials showed clinically acceptable performances in restoration of NCCLs in patients with bruxism.

An in vitro assessment of the residual dentin after using three minimally invasive caries removal techniques.

To evaluate the efficiency and effectiveness of three minimally invasive (MI) techniques in removing deep dentin carious lesions. Forty extracted carious molars were treated by conventional rotary excavation (control), chemomechanical caries removal agent (Brix 3000), ultrasonic abrasion (WOODPECKER, GUILIN, China); and Er, Cr: YSGG laser ablation (BIOLASE San Clemente, CA, USA). The assessments include; the excavation time, DIAGNOdent pen, Raman spectroscopy, Vickers microhardness, and scanning electron microscope combined with energy dispersive X-ray spectroscopy (SEM-EDX). The rotary method recorded the shortest excavation time (p < 0.001), Brix 3000 gel was the slowest. DIAGNOdent pen values ranged between 14 and 18 in the remaining dentin and laser-ablated surfaces recorded the lowest reading (p < 0.001). The Ca:P ratios of the remaining dentin were close to sound dentin after all excavation methods; however, it was higher in the ultrasonic technique (p < 0.05). The bur-excavated dentin showed higher phosphate and lower matrix contents with higher tissue hardness that was comparable to sound dentin indicating the non-selectiveness of this technique in removing the potentially repairable dentin tissue. In contrast, the MI techniques exhibited lower phosphate and higher organic contents associated with lower microhardness in the deeper dentin layers. This was associated with smooth residual dentin without smearing and patent dentinal tubules. This study supports the efficiency of using MI methods in caries removal as conservative alternatives to rotary excavation, providing a promising strategy for the clinical dental practice.

Investigation of the presence of Non-carious cervical lesions (NCCLs) in ancient adult skulls: analyzing data from prehistoric and historical samples through a systematic review and meta-analysis.

OBJECTIVES: Historically, the prevalence of caries has undergone significant changes, particularly increasing with the industrialization of sugar consumption. When examining ancient populations, lower caries rates are discovered, attributed in part to dietary factors. These populations consumed abrasive foods, leading to occlusal wear and reduced non-axial occlusal forces, potentially influencing Non-Carious Cervical Lesions (NCCLs). Although some attribute NCCLs to abfraction, the mechanism remains debated. This systematic review aims to evaluate the presence of NCCLs in ancient populations, shedding light on the factors contributing to their occurrence. MATERIALS AND METHODS: The present systematic review was registered on PROSPERO, and the manuscript was prepared following PRISMA guidelines. RESULTS: After the literature search and article screening, data from 6 studies were included in the meta-analysis, with only 2 reporting NCCLs in ancient skulls, encopassing 17 subjects in 805 examined skulls, suggesting their presence even before the widespread use of toothbrushes. This finding indicates a potential etiopathogenic mechanism linked to abfraction, but the cause is complex and involves abrasive and erosive factors closely tied to dietary habits. CONCLUSIONS: In summary, NCCLs were present in ancient populations, albeit with a much lower prevalence. Their occurrence cannot be solely attributed to wear mechanisms but must be connected to abrasive factors related to diet or practices with religious and cultural significance, such as the use of labrets. CLINICAL RELEVANCE: Th the knowledge of NCCLs presence in acient sculls is crucial today for better understand the associated risk factors. In this context, the analysis of ancient skulls allows us to discern the role that tooth brushing and diet played in the formation of NCCLs, over the past century.

Volumetric analysis after caries excavation with caries detecting dyes and chemomechanical caries removal agents using 3D scanner-a randomised clinical trial.

AIM: This research aimed to use an extra-oral 3D scanner for conducting volumetric analysis after caries excavation using caries-detecting dyes and chemomechanical caries removal agents in individuals with occlusal and proximal carious lesions. METHODS: Patients with occlusal (A1, A2, A3) and proximal carious lesions (B1, B2, B3) were treated with the conventional rotary technique, caries detecting dyes (CDD) and chemomechanical caries removal (CMCR) method on 90 teeth (n = 45 for each). Group A1, B1: Excavation was performed using diamond points. Group A2, B2: CDD (Sable Seek™ caries indicator, Ultradent) was applied and left for 10 s, and then the cavity was rinsed and dried. For caries removal, diamond points or excavators were used. Group A3 and B3: BRIX3000 papain gel was applied with a micro-brush for 20 s and was activated for 2 min, and then the carious tissue was removed with a sharp spoon excavator. Post-excavation cavity volume analysis was performed using a 3D scanner. The time required and the verbal pain score (VPS) for pain were scored during excavation. Post-restoration evaluation was performed at 1, 3, and 6 months FDI (Federation Dentaire Internationale) criteria. RESULTS: Comparison of age, time and volume with study groups were made using Independent Sample' t' test and one-way analysis of variance (ANOVA) for two and more than two groups, respectively. Using Cohen's Kappa Statistics, evaluators 1 and 2 agreed on caries removal status aesthetic, functional and biological properties at different follow-ups. The chi-square test revealed that the rotary groups [A1(2.5 ± 0.4 min) B1(4.0 ± 0.4 min)] had significantly less (p = 0.000) mean procedural time than CDD [A2(4.5 ± 0.4 min) B2(5.7 ± 0.4 min)] and CMCR [A3(5.4 ± 0.7 min) B3(6.2 ± 0.6 min)] groups. The CMCR group showed better patient acceptance and less pain during caries excavation than the rotary and CDD groups. CMCR group showed significantly less mean caries excavated volume(p = 0.000). Evaluation of restoration after 1-, 3-, and 6-month intervals was acceptable for all the groups. CONCLUSION: Brix3000 helps effectively remove denatured teeth with less pain or sensitivity. The time required for caries removal was lowest in the rotary method and highest in the brix3000 group, while the volume of caries removed was the lowest for brix3000 and highest for the rotary group.

Occlusal caries detection and monitoring using a 3D intraoral scanner system. An in vivo assessment.

OBJECTIVE: To assess the agreement in detecting and monitoring occlusal caries over thirty months using conventional visual and radiographic assessment and an intraoral scanner system which supports automated caries scoring. METHODS: Ninety-one young participants aged 12-19 years were included in the study. All occlusal surfaces were examined visually, radiographically (when indicated), and scanned with the TRIOS 4 intraoral scanner. TRIOS Patient Monitoring software (vers. 2.3, 3Shape TRIOS A/S, Denmark) was used for automated caries detection on the 3D digital models. RESULTS: Fifty-five of the study participants were re-examined after 30-months. Significant differences regarding caries detection were found between the conventional methods and the automated caries scoring system (p < 0.01), with moderate positive percent agreement (49-61%) and high negative percent agreement (87-98%). All methods reported significant caries progression over the follow-up period (p < 0.01). However, the automated system showed significantly more caries progression than the other methods (p < 0.01). CONCLUSIONS: The software for automated caries detection and classification showed moderate positive agreement and strong negative agreement with the conventional methods considering both the baseline and the follow-up assessments. The automated caries scoring system detected significantly fewer caries lesions and tended to underestimate the caries severity. All methods indicated significant caries progression over the follow-up period, while the automated system detected more caries progression. CLINICAL SIGNIFICANCE: The TRIOS system supporting automated occlusal caries detection and classification can assist in detecting and monitoring occlusal caries on permanent teeth as a complementary tool to the conventional methods. However, the operator should be aware that the automated system shows a tendency to underestimate the caries presence and lesion severity.

Effect of calcium-coacervate infiltration of artificial enamel caries lesions in de- and remineralizing conditions.

OBJECTIVES: Calcium-coacervate emulsions (CC) might be considered as mineral precursors to foster remineralization of carious dental hard tissues. This study analyzed the instant effect of repeated infiltration of artificial caries lesions with a CC emulsion as well as the effects of subsequent exposure of CC-infiltrated lesions to demineralizing and remineralizing environments. METHODS: Bovine enamel specimens were partly covered with varnish to leave three exposed windows. Artificial enamel caries lesions were created (pH 4.95, 17d). Baseline controls (BL) were obtained by preparing a thin section of each specimen. Specimens were allocated to five groups. In three groups lesions were etched with 37 % phosphoric acid gel, infiltrated with dipotassium hydrogen phosphate and subsequently with a calcium coacervate emulsion, prepared by mixing CaCl2 ⋅ 2H2O with polyacrylic acid sodium salt (PAA-Na). Subsequently, the infiltration effect was either analyzed immediately (Inf.) or after exposition to either de- (Inf.+DS) or remineralizing solution (Inf.+RS) for 10 or 20 days, respectively. In two control groups specimens were exposed to either DS or RS, respectively without prior CC infiltration. Integrated mineral loss [ΔZ(vol%×µm)] was analyzed using transverse microradiography (TMR). RESULTS: Infiltration of enamel caries lesions with coacervate solution resulted in only subtle immediate mineral gain even if repeated. When exposed to demineralizing conditions, infiltrated lesions showed significantly less mineral loss compared to untreated controls (p < 0.05; Kruskal Wallis) and exhibited characteristic mineral depositions within the lesion body. CONCLUSIONS: While immediate mineral gain by infiltration was only modest, the CC-emulsion might be able to prevent demineralization in acidic conditions. CLINICAL SIGNIFICANCE: Calcium coacervates might act protective against further demineralization when infiltrated into enamel caries lesions.

Use of micro-computed tomography and scanning electron microscopy with energy-dispersive spectroscopy to distinguish natural white spot enamel lesions from sound enamel in human premolars.

PURPOSE: The aim of the present study was to develop a novel method for distinguishing white spot lesions (WSLs) from sound enamel in human premolars using micro-computed tomography (micro-CT) and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and to examine differences in surface morphology, chemical composition, and mineral density (MD) between these two areas. METHODS: Fourteen premolars with natural WSLs on the enamel surface of the crowns were examined. After sectioning the teeth, each specimen containing WSLs adjacent to intact enamel was examined for MD, surface morphology, and atomic percentages (At%) of chemical components using micro-CT and SEM/EDS, respectively. Differences between these areas of the same specimen were analyzed statistically using paired t-test. RESULTS: SEM images highlighted increased roughness and irregularity in the lesion area. EDS analysis revealed significant reductions in calcium (Ca), phosphorus (P), fluorine (F), chlorine (Cl), and sodium (Na) levels at the lesion surface in comparison to intact enamel (P < 0.05). The decreases in the MD of the lesions were statistically significant in comparison to sound enamel (P < 0.05). CONCLUSION: These findings provide standard measurements for evaluating the essential characteristics of WSLs and intact enamel, being vital for assessment of treatment outcomes and development of innovative biomaterials for management of hypo-mineralized enamel lesions.

Visualization of etching cycles efficacy at the resin infiltration into artificial enamel caries: in-vitro study on bovine teeth.

This study evaluated the effect of repeated etching cycles on resin infiltrant penetration. Enamel samples measuring 4 × 4 × 3 mm3 were obtained from the facial aspect of 50 extracted bovine teeth. Samples were immersed in a demineralization solution for 21 days to create artificial lesions and divided into five equal groups (n = 10). A 15% hydrochloric acid gel was administered to each group. The acid etching application time differed between groups: Group 1; 2 min, Group 2; 2 × 2 min, Group 3; 3 × 2 min, Group 4; 4 × 2 min, and Group 5; 5 × 2 min. Resin infiltration was visualized using a confocal laser scanning microscopy. The lesion, penetration and erosion depth (µm) were calculated, and data were statistically analyzed. The highest penetration depth (75.59 ± 9.42 µm) was seen in Group 5, followed by Groups 4, 3, 2 and 1. However, there were no statistically significant differences in the penetration depths between Groups 4 and 5 and between Groups 2, 3 and 4 (p > 0.05). In conclusion, a repeated etching cycle enhanced resin infiltrant penetration.

Endodontic Treatment of a Maxillary Incisor Tooth in a Chimpanzee (Pan troglodytes).

Chimpanzees (Pan troglodytes) with teeth severely damaged by dental caries and/or periodontal disease are often managed with medication and/or tooth extraction. A common endodontic treatment for severely decayed teeth in a 26-year-old female chimpanzee is reported. The left maxillary central incisor tooth had lost its crown, probably due to trauma that was not recent, and it had a fistula most likely due to chronic apical periodontitis. The diagnosis was confirmed radiographically before treatment. To treat the infected root canal, endodontic treatment used in humans was adapted for a chimpanzee. After the treatment, the tooth was sealed using an adhesive resin composite. At 11-years post-treatment, there were no signs of recurrence of the lesion or of failure of the tooth seal. The results of this case report suggest that common endodontic treatments used in humans are also effective in chimpanzees.

In vitro caries-preventive effect of a mineralization-promoting peptide combined with fluoride gel on sound primary teeth.

BACKGROUND: Mineralization-promoting peptide-3 (MPP3) is a new biomimetic remineralization agent. AIM: To assess the remineralization efficiency of MPP3, either alone or in combination with fluoride gel. DESIGN: The samples were divided into four groups: control, 1.23% fluoride gel, 10% MPP3 gel, and 1.23% fluoride gel + 10% MPP3. Following the application of remineralization agents (4 min), the samples remained in a pH-cycling model (37°C, 4 weeks). Microhardness, microcomputed tomography (micro-CT), polarized light microscopy (PLM), and field emission scanning electron microscopy (FE-SEM) analysis were conducted. RM-ANOVA, one-way ANOVA, and intraclass correlation coefficient (ICC) were used for statistical analysis, and a significance level of p < .05 was employed. RESULTS: Mineralization-promoting peptide 3 and fluoride gel + MPP3 increased the microhardness of the enamel compared with initial values in each group (p < .05). Mineralization-promoting peptide 3 successfully maintained the mineral density of enamel, although the cariogenic pH-cycling and PLM results indicated that the lesion depth (µm) was significantly lower in the fluoride gel + MPP3 group (27.0336 ± 12.53650) than in the control group (37.3907 ± 12.76002, p < .05). CONCLUSION: The combined use of MPP3 with fluoride gel enhanced the caries-protective and mineralization-promoting effects of fluoride. Mineralization-promoting peptide 3 may be a potential agent that can be employed to improve the physical properties of enamel.

Impact of artificial intelligence on dentists' gaze during caries detection: A randomized controlled trial.

OBJECTIVES: We aimed to understand how artificial intelligence (AI) influences dentists by comparing their gaze behavior when using versus not using an AI software to detect primary proximal carious lesions on bitewing radiographs. METHODS: 22 dentists assessed a median of 18 bitewing images resulting in 170 datasets from dentists without AI and 179 datasets from dentists with AI, after excluding data with poor gaze recording quality. We compared time to first fixation, fixation count, average fixation duration, and fixation frequency between both trial groups. Analyses were performed for the entire image and stratified by (1) presence of carious lesions and/or restorations and (2) lesion depth (E1/2: outer/inner enamel; D1-3 outer-inner third of dentin). We also compared the transitional pattern of the dentists' gaze between the trial groups. RESULTS: Median time to first fixation was shorter in all groups of teeth for dentists with AI versus without AI, although p>0.05. Dentists with AI had more fixations (median=68, IQR=31, 116) on teeth with restorations compared to dentists without AI (median=47, IQR=19, 100), p = 0.01. In turn, average fixation duration was longer on teeth with caries for the dentists with AI than those without AI; although p>0.05. The visual search strategy employed by dentists with AI was less systematic with a lower proportion of lateral tooth-wise transitions compared to dentists without AI. CONCLUSIONS: Dentists with AI exhibited more efficient viewing behavior compared to dentists without AI, e.g., lesser time taken to notice caries and/or restorations, more fixations on teeth with restorations, and fixating for shorter durations on teeth without carious lesions and/or restorations. CLINICAL SIGNIFICANCE: Analysis of dentists' gaze patterns while using AI-generated annotations of carious lesions demonstrates how AI influences their data extraction methods for dental images. Such insights can be exploited to improve, and even customize, AI-based diagnostic tools, thus reducing the dentists' extraneous attentional processing and allowing for more thorough examination of other image areas.