Genetic/Protein Association of Atopic Dermatitis and Tooth Agenesis.

Atopic dermatitis and abnormalities in tooth development (including hypomineralization, hypodontia and microdontia) have been observed to co-occur in some patients. A common pathogenesis pathway that involves genes and protein interactions has been hypothesized. This review aims to first provide a description of the key gene mutations and signaling pathways associated with atopic dermatitis and tooth agenesis (i.e., the absence of teeth due to developmental failure) and identify the possible association between the two diseases. Second, utilizing a list of genes most commonly associated with the two diseases, we conducted a protein-protein network interaction analysis using the STRING database and identified a novel association between the Wnt/ß-catenin signaling pathway (major pathway responsible for TA) and desmosomal proteins (component of skin barrier that affect the pathogenesis of AD). Further investigation into the mechanisms that may drive their co-occurrence and underlie the development of the two diseases is warranted.

Salivary biomarkers for dental caries.

As a highly prevalent multifactorial disease, dental caries afflicts a large proportion of the world's population. As teeth are constantly bathed in saliva, the constituents and properties of this oral fluid play an essential role in the occurrence and progression of dental caries. Various inorganic (water and electrolytes) and organic (proteins and peptides) components may protect teeth from dental caries. This occurs via several functions, such as clearance of food debris and sugar, aggregation and elimination of microorganisms, buffering actions to neutralize acid, maintaining supersaturation with respect to tooth mineral, participation in formation of the acquired pellicle and antimicrobial defense. Modest evidence is available on the associations between dental caries and several salivary parameters, including flow rate, buffering capacity and abundance of mutans streptococci. Despite some controversial findings, the main body of the literature supports an elevated caries prevalence and/or incidence among people with a pathologically low saliva flow rate, compromised buffering capacity and early colonization or high titer of mutans streptococci in saliva. The evidence remains weak and/or inconsistent on the association between dental caries and other saliva parameters, such as other possible cariogenic species (Lactobacillus spp., Streptococcus sanguis group, Streptococcus salivarius, Actinomyces spp. and Candida albicans), diversity of saliva microbiomes, inorganic and organic constituents (electrolytes, immunoglobulins, other proteins and peptides) and some functional properties (sugar clearance rate, etc.). The complex interactions between salivary components and functions suggest that saliva has to be considered in its entirety to account for its total effects on teeth.

Early-life factors affect risk of pain and fever in infants during teething periods.

AIM: This longitudinal study aimed to investigate the prevalence of teething-related pain and fever and the early-life factors that may affect the risk of experiencing these disturbances within the first 1.5 years of life. MATERIALS AND METHODS: Participants were recruited (n = 1033) through the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort (n = 1237). Interviews were performed tri-monthly regarding the prevalence of teething pain and fever in children from 6 to 18 months of age. Crude and multivariable analyses were conducted using Poisson-log regression models. RESULTS: Prevalence rates for teething pain and fever were 35.5 and 49.9 % respectively. Multivariable Poisson regression analysis showed maternal second-hand tobacco smoke (SHS) exposure to increase the risk of both pain (mean ratio = 1.35; p = 0.006) and fever (mean ratio = 1.22; p = 0.025), whereas SHS exposure plus active smoking further increased risk of teething pain in the children (mean ratio = 1.89; p = 0.029). Delivery via Caesarean section increased risk of teething pain (mean ratio = 1.27; p = 0.033), while prenatal plasma vitamin D insufficiency lowered such a risk (mean ratio = 0.62; p = 0.012). Compared to Chinese infants, Indian babies exhibited lower risk of teething pain and fever (both p ≤ 0.001). CONCLUSIONS: Early-life factors such as tobacco smoke exposure and vitamin insufficiency during pregnancy, ethnicity and childbirth via Caesarean section may significantly affect the child's susceptibility to teething-related pain and fever. CLINICAL RELEVANCE: Knowledge of prevalence and risk factors of teething disturbances may better equip primary caregivers and healthcare professionals to accurately detect teething-related local and/or systemic signs/symptoms and effectively facilitate tobacco cessation among pregnant women.

Influence of metabolic-linked early life factors on the eruption timing of the first primary tooth.

AIM: Early eruption of permanent teeth has been associated with childhood obesity and diabetes mellitus, suggesting links between tooth eruption and metabolic conditions. This longitudinal study aimed to identify pre-, peri- and postnatal factors with metabolic consequences during infancy that may affect the eruption timing of the first primary tooth (ETFT) in children from an ethnically heterogeneous population residing within the same community. MATERIAL AND METHODS: Participants were recruited (n = 1033) through the GUSTO (Growing Up in Singapore Towards healthy Outcomes) birth cohort (n = 1237). Oral examinations were performed at 3-month intervals from 6 to 18 months of age. Crude and adjusted analyses, with generalized linear modelling, were conducted to link ETFT to potential determinants occurring during pregnancy, delivery/birth and early infancy. RESULTS: Overall mean eruption age of the first primary tooth was 8.5 (SD 2.6) months. Earlier tooth eruption was significantly associated with infant's rate of weight gain during the first 3 months of life and increased maternal childbearing age. Compared to their Chinese counterparts, Malay and Indian children experienced significantly delayed tooth eruption by 1.2 and 1.7 months, respectively. CONCLUSIONS: Infant weight gain from birth to 3 months, ethnicity and maternal childbearing age were significant determinants of first tooth eruption timing. Early life influences can affect primary tooth development, possibly via metabolic pathways. CLINICAL RELEVANCE: Timing of tooth eruption is linked to general growth and metabolic function. Therefore, it has potential in forecasting oral and systemic conditions such as caries and obesity.

pH-Responsive Hybrid Nanoparticles for Imaging Spatiotemporal pH Changes in Biofilm-Dentin Microenvironments.

Engineering highly sensitive nanomaterials to monitor spatiotemporal pH changes has rather broad applications in studying various biological systems. Intraoral/biofilm-tooth pH is the single parameter that has demonstrated accurate assessment of dental caries risk, reflecting the summative integrated outcome of the complicated interactions between three etiological factors, namely, microorganisms/biofilm, diet/carbohydrates, and tooth/saliva/host. However, there is little to no technology/system capable of accurately probing simultaneously both the micro-pH profiles in dentin tissues and acidogenic oral biofilms and examining the pathophysiologic acid attacks with high spatial/temporal resolution. Therefore, a highly sensitive pH-responsive hybrid nanoparticle (pH-NP) is developed and coupled with an ex vivo tooth-biofilm caries model to simulate and study the key cariogenic determinants/steps. The pH-NP emits two distinct fluorescences with mutually inversely proportional intensities that vary accordingly to the proximity pH and with a ratiometric output sensitivity of 13.4-fold across a broad clinically relevant pH range of 3.0-8.0. Using [H+], in addition to pH, to calculate the "area-under-curve" corroborates the "minimum-pH" in semiquantifying the demineralizing potential in each biofilm-dentin zones/depth. The data mechanistically elucidates a two-pronged cariogenic effect of a popular-acidic-sweet-drink, in inundating the biofilm/tooth-system with H+ ions from both the drink and the metabolic byproducts of the biofilm.

Internalizing problems are associated with oral health-related quality of life in early childhood: Outcomes from an Asian multi-ethnic prospective birth cohort.

Oral health status ideally warrants for a holistic biopsychosocial approach to health and wellness. Little is known about the impact of behavioral problems on oral health-related quality of life (OHRQoL) in children due to the paucity of studies in early childhood, particularly in Asian multi-ethnic populations. This study evaluated the relationship between early child's socioemotional factors and OHRQoL, as well as its association with orofacial pain (OFP) and early childhood caries (ECC) in the Asian GUSTO birth cohort. Mother-child dyads were postnatally assessed at 3 time points. The Child Behavior Checklist (CBCL) was used to assess the child's socioemotional and behavioral problems at age 4-4.5 years together with other validated questionnaires to evaluate maternal anxiety and depression. ECC detection was performed at age 5, and OHRQoL (primary) and OFP (secondary) outcomes were assessed at age 6 from a total of 555 mother-child dyads. After a univariate regression analysis was performed to identify potential predictors and confounders, a multivariate regression model was run with predisposing factors (CBCL internalization and externalization problems, OFP, ECC) and adjusted for confounders (maternal psychosocial states, maternal education) to determine associations with OHRQoL. Results showed an association between CBCL internalization scores and poorer OHRQoL (RR = 1.03, p = 0.033, 95% CI 1.01 to 1.05), although the limited risk ratio may not have a practical applicability in psychosocially healthy children, alike the majority of those evaluated in this cohort. The average OHRQoL overall score among children with OFP was 2.39 times more than those without OFP (OR = 2.39, p < 0.001, 95% CI 2.00 to 2.86). Thus, in early childhood, OFP, and to lesser extent internalizing behaviors, may negatively impact OHRQoL. This study therefore highlights the complex relationship between OHRQoL and its predisposing socioemotional and somatic pain factors, and demands further investigations in clinically relevant populations.

Dental plaque pH in predicting caries relapse after general anaesthesia - an exploratory study.

OBJECTIVES: Numerous caries risk assessment tools have been proposed in the literature, with few validated in preschool children especially those receiving oral rehabilitation under general anaesthesia (GA). Past caries experience, the best predictor thus far, may not be a reliable indicator after effective clinical intervention. Hence, this longitudinal study was aimed to explore the potential role of plaque pH in predicting future caries incidence after GA among preschool children. METHODS: Oral examination, plaque pH measurements and questionnaire survey were performed, among pre-schoolers indicated for GA, at baseline (n = 92), 6-month (6M; n = 83), 12-month (12M; n = 79) and 24-month (24M; n = 66) recall visits after GA. Multivariable logistic regression and receiver-operating characteristic analysis were performed to evaluate the predictive value of models with plaque pH and past caries experience. RESULTS: Individuals with low resting plaque pH at 6M and 12M were shown to be at high risk of 1-year caries incidence at 12M [relative risk (RR) 1.41, 95% confidence interval (CI) 1.09-1.48] and 24M (RR 1.61, 95% CI 1.22-1.73) recall visit, respectively. Moreover, plaque pH demonstrated a statistically significant predictive value in the 12M and 24M models (12M/24M: 85%/77%) compared with past caries experience, which was not a significant predictor in both models (both P > 0.05). CONCLUSIONS: Plaque pH may be a promising prognostic and predictive marker for early identification of high-risk children undergoing oral rehabilitation under GA.

Identifying Positive Adaptive Pathways in Low-Income Families in Singapore: Protocol for Sequential, Longitudinal Mixed-Methods Design.

BACKGROUND: This study aims to examine the adaptive process of children and mothers from multistressed low-income families in Singapore. It aims to bridge the knowledge gap left by existing poverty studies, which are predominately risk focused. Through a sequential longitudinal mixed-methods design, we will differentiate children and mothers who demonstrate varied social, developmental, and mental health trajectories of outcomes. Through utilizing the Latent Growth Curve Model (LGCM), we aim to detect the development and changes of the positive Family Agency and adaptive capacities of these families over time. The construct of Family Agency is underpinned by the theoretical guidance from the Social Relational Theory, which examines child agency, parent agency, relational agency, and the interactions among these members. It is hypothesized that positive Family Agency within low-income families may lead to better outcomes. The key research questions include whether the extent of positive Family Agency mediates the relationship among financial stress, resource utilization, home environment, and parental stress. OBJECTIVE: The study elucidates the Family Agency construct through interviews with mother-child dyads. It also aims to understand how financial stress and resources are differentially related to home environment, parent stress, and parent and child outcomes. METHODS: In phase 1, 60 mother-child dyads from families receiving government financial assistance and with children aged between 7 and 12 years will be recruited. In-depth interviews will be conducted separately with mothers and children. On the basis of 120 interviews, a measurement for the construct of Family Agency will be developed and will be pilot tested. In phase 2a, a longitudinal survey will be conducted over 3 time points from 800 mother-child dyads. The 3 waves of survey results will be analyzed by LGCM to identify the trajectories of adaptation pathways of these low-income families. In addition, 10 focus groups with up to 15 participants in each will be conducted to validate the LGCM results. RESULTS: This project is funded by the Social Science Research Thematic Grant (Singapore). The recruitment of 60 mother-child dyads has been achieved. Data collection will commence once the amendment to the protocol has been approved by the Institutional Review Board. Analysis of phase 1 data will be completed by the end of the first quarter of 2019, and the first set of results is expected to be submitted for publication by the second quarter of 2019. Phase 2 implementation will commence in the second quarter of 2019, and the project end date is in May 2021. CONCLUSIONS: Findings from this study can potentially inform social policy and programs as it refines the understanding of low-income families by distinguishing trajectories of adaptive capacities so that policies and interventions can be targeted in enhancing the adaptive pathways of low-income families with children. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/11629.

Infant dietary patterns and early childhood caries in a multi-ethnic Asian cohort.

Dental caries, although preventable, remains one of the most prevalent chronic disease worldwide. Most studies focused on the relationship between sugar intake and caries. However, examining multidimensional dietary patterns is becoming increasingly important. Here, we examined the relationship between dietary patterns from ages 6 to 12 months and early childhood caries (ECC) at age 2 to 3-years. Infant dietary data was collected from caregivers and dietary pattern trajectories from 6 to 12 months derived. Oral examinations were carried out by trained calibrated dentists at ages 2 and 3 years. Associations between dietary pattern and ECC were estimated using generalized estimating equation. We found a 3.9 fold lower prevalence of decayed surfaces among children with high Guidelines dietary pattern scores at 6-months (IRR 0.26; CI [0.12-0.53]; p-value < 0.001) and 100% reduction of decayed surfaces with increased intakes of Guidelines dietary pattern foods from 6 to 12-month (IRR 2.4 × 10-4; CI [4.2 × 10-7-0.13]; p-value = 0.01). Suggesting that following the Guideline dietary pattern, which corresponds most closely to current World Health Organization weaning guidelines, at 6 months and an increase in pattern score between 6 and 12 months were protective against ECC development compared to Predominantly breastmilk, Easy-to-prepare foods and Noodles (in soup) and seafood dietary patterns.

Risk assessment models to predict caries recurrence after oral rehabilitation under general anaesthesia: a pilot study.

OBJECTIVES: Oral rehabilitation under general anaesthesia (GA), commonly employed to treat high caries-risk children, has been associated with high economic and individual/family burden, besides high post-GA caries recurrence rates. As there is no caries prediction model available for paediatric GA patients, this study was performed to build caries risk assessment/prediction models using pre-GA data and to explore mid-term prognostic factors for early identification of high-risk children prone to caries relapse post-GA oral rehabilitation. METHODS: Ninety-two children were identified and recruited with parental consent before oral rehabilitation under GA. Biopsychosocial data collection at baseline and the 6-month follow-up were conducted using questionnaire (Q), microbiological assessment (M) and clinical examination (C). RESULTS: The prediction models constructed using data collected from Q, Q + M and Q + M + C demonstrated an accuracy of 72%, 78% and 82%, respectively. Furthermore, of the 83 (90.2%) patients recalled 6 months after GA intervention, recurrent caries was identified in 54.2%, together with reduced bacterial counts, lower plaque index and increased percentage of children toothbrushing for themselves (all P < 0.05). Additionally, meal-time and toothbrushing duration were shown, through bivariate analyses, to be significant prognostic determinants for caries recurrence (both P < 0.05). CONCLUSIONS: Risk assessment/prediction models built using pre-GA data may be promising in identifying high-risk children prone to post-GA caries recurrence, although future internal and external validation of predictive models is warranted.

Laser-induced compositional changes on enamel: a FT-Raman study.

UNLABELLED: Preventive effects of lasers on enamel caries have been documented in the past few decades. However, its specific mechanism remains uncertain. OBJECTIVES: To evaluate the laser-induced change of enamel compositions, including carbonate and organic matters using Fourier-transform Raman spectroscopy (FT-Raman). METHODS: Twelve windows (1 mm x 1 mm), created on six defect-free primary incisors, were characterized by FT-Raman microscopy (1024 nm) before and after Er:YAG laser treatment (Fidelis) with 5.1 J/cm(2)-2 Hz-5s. To assess the statistical significance of laser effects, Raman peaks assigned to nu(1) phosphate, type-A/B carbonates, and organic matters were evaluated with the paired-samples t-test. RESULTS: The standardized intensity of type B carbonate decreased significantly from 0.117 to 0.106 (p=0.029), whereas the standardized intensity of carbonate A remained unchanged (p=0.467). Related to organic matters, the standardized intensity of peaks at 2940 cm(-1) and in the ranges of 1200-1600 cm(-1) decreased significantly, with p=0.005 and p<0.001, respectively. Revealing enamel crystallinity, the bandwidth of nu(1) phosphate on lased surfaces appeared to be unaltered after laser treatment (p=0.477). CONCLUSIONS: Laser treatment may provide caries-preventive effect on enamel through reduction of carbonate and modification of organic matters.

Effects of Lactobacillus casei Shirota intake on caries risk in children.

BACKGROUND/PURPOSE: Yakult is a well-known probiotic beverage consisting of a single live bacterial species, Lactobacillus casei Shirota. However, the potential cariogenic/cariostatic effects of Yakult intake among children have not been studied yet. Hence, this study aimed to investigate the clinical effects of short-term Yakult intake on oral biofilm acidogenicity, cariogenic bacterial counts, and caries risk in children. MATERIALS AND METHODS: Eighteen children, 7-11 years of age, consumed standard Yakult daily for 7 days. Prior to and after intervention, functional oral biofilm acidogenicity characterized by the Stephan curve, Lactobacillus and Streptococcus mutans counts, and caries risk were determined. RESULTS: Probiotic intervention demonstrated significant increase in minimum pH from 4.88 to 5.14 (P = 0.02), 18.2% reduction in area under the Stephen curve [area under the curve (AUC)], and 29.3% decrease in pH recovery time, although these two differences were not statistically significant. No difference was observed in S. mutans and Lactobacillus counts or caries risk after intervention (all P > 0.05). However, on subgroup analysis using "reduction of AUC" to separate "responders" from the "nonresponders", the significant cariostatic effects on oral biofilm acidogenicity, among "responders", were revealed by an increase in minimum pH (P = 0.005) and a reduction in pH recovery time (P = 0.003). CONCLUSION: There may be a potential cariostatic effect of short-term Yakult intake in reducing functional biofilm acidogenicity in children with certain oral biofilm and risk profile. Further studies may be needed to validate this probiotic effect. Quality risk assessment may be critical prior to prescribing/recommending Yakult as an adjunct caries-preventive treatment for children.

Erbium Lasers for the Prevention of Enamel and Dentin Demineralization: A Literature Review.

OBJECTIVE: The aim of this article is to review the current literature concerning Erbium lasers: Er:YAG (λ=2.94µm), Er:YSGG (λ=2.79µm), and Er,Cr:YSGG (λ=2.78µm) for the prevention of enamel and dentin demineralization. METHODS: Features such as laser parameters, reported outcome, inhibition of demineralization, and mechanisms of laser action were analyzed. A total of 55 publications were found in four electronic databases and were complemented by hand searching. RESULTS: Evidence regarding the potential of laser-induced prevention of demineralization (LIPD) was demonstrated in the literature, especially when subablative parameters were applied. Although ablation parameters have shown partial positive results in LIPD, some studies have shown severe morphological alterations in enamel and dentin. Until now, there are still no reports on the long-term effects of laser treatment. Additionally, it is unclear if there is a best combination of mechanisms that leads to the optimal LIPD. Other variables that are poorly investigated in the literature and have an important role in LIPD include pulse width, water irrigation, and air flow. CONCLUSIONS: This review demonstrates the current knowledge concerning the use of erbium lasers in LIPD, and brings forth essential questions that should be further addressed.

Role of microbiological factors in predicting early childhood caries.

PURPOSE: Microbiological methods that accurately identify caries-susceptible children may enhance caries control and assist treatment planning. This study's purpose was to evaluate the usefulness of two microbiological indicators (mutans streptococci [MS] and lactobacilli [LB] levels), singly and in combination, for predicting early childhood caries (ECC) and their contributions in multifactorial modeling. METHODS: A total of 1,782 randomly selected three- to five-year-olds were recruited and underwent oral examination and microbiological tests using commercially available diagnostic kits. A questionnaire was completed by their parents. After 12 months, the caries increment in 1,576 (∼88 percent) children was assessed. RESULTS: Caries risk increased with the MS and LB levels but plateaued above the LB level of 10(5) CFU/ml saliva. MS, LB, and combined MS+LB models predicted one-year caries increment (Δdmft>0) with a sensitivity/specificity of 79 percent/67 percent, 51 percent/89 percent, and 66 percent/85 percent, respectively. Sensitivity/specificity reached 80 percent/80 percent when baseline caries experience ("past caries") was added to the MS+LB model and up to 85 percent/80 percent and 81 percent/85 percent when psychosociobehavioral factors and oral hygiene status were added to the MS+LB model, without and with "past caries," respectively. CONCLUSIONS: The combined "mutans streptococci+lactobacilli+past caries" model is useful for identifying at-risk children. Incorporating MS and LB into a biopsychosociobehavioral model slightly improved the prediction, even without "past caries".

Validity of caries risk assessment programmes in preschool children.

OBJECTIVES: Various programmes have been developed for caries risk assessment (CRA). Nevertheless, scientific evidence on their validity is lacking. This study aimed to compare the validity of 4 CRA programmes (CAT, CAMBRA, Cariogram, and NUS-CRA) in predicting early childhood caries. METHODS: A total of 544 children aged 3 years underwent oral examination and biological tests (saliva flow rate, salivary buffering capacity and abundance of cariogenic bacteria mutans Streptococci and Lactobacilli). Their parents completed a questionnaire. Children's caries risk was predicted using the 4 study programmes without biological tests (screening mode) and with biological tests (comprehensive mode). After 12 months, caries increment in 485 (89%) children was recorded and compared with the baseline risk predictions. RESULTS: Reasoning-based programmes (CAT and CAMBRA screening) had high sensitivity (≥ 93.8%) but low specificity (≤ 43.6%) in predicting caries in children. CAMBRA comprehensive assessment reached a better balance (sensitivity/specificity of 83.7%/62.9%). Algorithm-based programmes (Cariogram and NUS-CRA) generated better predictions. The sensitivity/specificity of NUS-CRA screening and comprehensive models were 73.6%/84.7% and 78.1%/85.3%, respectively, higher than those of the Cariogram screening (62.9%/77.9%) and comprehensive assessment (64.6%/78.5%). NUS-CRA comprehensive model met the criteria for a useful CRA tool (sensitivity+specificity ≥ 160%), while its screening model approached that target. CONCLUSIONS: Our results supported algorithm-based approach of caries risk modelling and the usefulness of NUS-CRA in identifying children susceptible to caries. CLINICAL SIGNIFICANCE: This prospective study provided evidence for practitioners to select tools for assessing children's caries risk, so that prevention measures can be tailored and treatment plan can be optimised.

Lesion progression in post-treatment persistent endodontic lesions.

INTRODUCTION: Radiographic lesions related to root-filled teeth may persist for long periods after treatment and are considered to indicate failure of initial treatment. Persistent lesions are found in a proportion of cases, but information on lesion progression is lacking. This study examined the incidence of lesion improvement, remaining unchanged, and deterioration among persistent lesions in a group of patients recruited from a university-based clinic and identified potential predictors for lesion progression. METHODS: Patients of a university clinic with persistent endodontic lesions at least 4 years since treatment and with original treatment radiographs available were recruited with informed consent. Data were obtained by interview and from dental records and clinical and radiographic examinations. Univariate and multivariate statistical analyses were carried out by using SPSS (version 19). RESULTS: One hundred fifty-one persistent lesions were identified in 114 patients. A majority of the lesions (107, 70.9%) received treatment between 4 and 5 years prior. Eighty-six lesions (57.0%) improved, 18 (11.9%) remained unchanged, and 47 (31.1%) deteriorated since treatment. Potential predictors for lesions that did not improve included recall lesion size, pain on biting at recall examination, history of a postobturation flare-up, and a non-ideal root-filling length (P < .05). Lesions that had persisted for a longer period appeared less likely to be improving (relative risk, 1.038; 95% confidence interval, 1.000-1.077). CONCLUSIONS: A specific time interval alone should not be used to conclude that a lesion will not resolve without intervention. This study identified several clinical factors that are associated with deteriorating persistent lesions, which should aid in identifying lesions that require further intervention.

Imaging carious dental tissues with multiphoton fluorescence lifetime imaging microscopy.

In this study, multiphoton excitation was utilized to image normal and carious dental tissues noninvasively. Unique structures in dental tissues were identified using the available multimodality (second harmonic, autofluorescence, and fluorescence lifetime analysis) without labeling. The collagen in dentin exhibits a strong second harmonic response. Both dentin and enamel emit strong autofluorescence that reveals in detail morphological features (such as dentinal tubules and enamel rods) and, despite their very similar spectral profiles, can be differentiated by lifetime analysis. Specifically, the carious dental tissue exhibits a greatly reduced autofluorescence lifetime, which result is consistent with the degree of demineralization, determined by micro-computed tomography. Our findings suggest that two-photon excited fluorescence lifetime imaging may be a promising tool for diagnosing and monitoring dental caries.