Relationship between laser fluorescence and enamel hypomineralisation

Non-Invasive Strategies for Remineralization and Hypersensitivity Management in Molar-Incisor Hypomineralization-A Systematic Review and Meta-Analysis

Background: Molar-incisor hypomineralization (MIH) is an enamel defect affecting molars and incisors, often leading to hypersensitivity, enamel breakdown, and increased caries risk. Non-invasive treatments, such as casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride varnish, show potential in remineralizing affected enamel and reducing sensitivity, but their efficacy is still debated. This study systematically reviews and analyzes the effectiveness of CPP-ACP and other non-invasive agents in improving remineralization and reducing hypersensitivity in MIH-affected teeth. Methods: A systematic search was conducted on PubMed, Embase, and Central in July 2024, including interventional and observational studies on remineralization and hypersensitivity in pediatric MIH patients (<18 years). A total of 1566 studies were found, with 15 included in the meta-analysis. A random-effects model was applied, including subgroup analysis by lesion severity. Results: CPP-ACP showed no statistically significant advantage over fluoride in remineralization (MD -3.80, 95% CI: -8.57; 0.98), but it significantly reduced hypersensitivity compared to fluoride varnish (MD -2.36, 95% CI: -3.83; -0.89). Although this reduction in hypersensitivity may be clinically relevant, the high heterogeneity (I² = 83%) and wide confidence intervals limit the reliability of these findings. Conclusions: CPP-ACP has a moderate effect in reducing hypersensitivity but does not outperform fluoride in remineralization. Other agents, such as calcium glycerophosphate and silver diamine fluoride, showed mild benefits. The current evidence base is limited and heterogeneous, highlighting the need for high-quality, long-term studies to confirm these findings and guide MIH management.

Effectiveness of resin infiltration in the management of anterior teeth affected by molar incisor hypomineralisation (MIH): A systematic review and meta-analysis

OBJECTIVES

To evaluate the effectiveness of resin infiltration in improving the aesthetic appearance of anterior teeth affected by molar-incisor hypomineralisation (MIH).

DATA SOURCES

PubMed, Scopus, EMBASE, Web of Science, ScienceDirect, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched from 2009 to 2024. The protocol was registered in the International Prospective Database of Systematic Reviews (PROSPERO CRD42023461909).

STUDY SELECTION

Interventional or comparative studies comparing resin infiltration and other treatments in MIH-affected anterior teeth were included. The risk of bias was evaluated using the Risk Of Bias In Non-randomised Studies of Interventions (ROBINS-I tool) and the Risk of Bias 2 (RoB 2.0) tool. Meta-analysis utilized a random-effects model.

DATA

Eighteen studies met the inclusion criteria, and twelve were included in the meta-analysis. Resin infiltration showed a higher color difference (ΔE) before and after treatment (mean difference 2.21, 95 % confidence interval [CI] 0.04-4.38, p < 0.001, I2 = 98.61 %, p < 0.001) and better optical improvement (standardised mean difference [SMD] 2.68; 95 %CI 0.30-5.06; p = 0.027, I2 = 97.8 %, p < 0.001) compared to controls. The estimated success rate based on dentist assessment was 92 % (95 %CI 88-95 %, I2 = 17.92 %, p = 0.06). Non-randomised trials showed high (8/14) or moderate (6/14) risk of bias, mainly from confounding and selection issues. Randomised trials had high risk (1/3) or some concerns (2/3) due to missing data.

CONCLUSIONS

The findings suggest that resin infiltration significantly improves aesthetic outcomes in MIH-affected anterior teeth, as evidenced by higher colour difference and optical improvement compared to controls.

CLINICAL SIGNIFICANCE

While our study shows promising results for resin infiltration, including high success rates and aesthetic improvements, larger-scale studies with longer follow-up periods are necessary to confirm these findings and assess its long-term efficacy.

Diagnostic validity of ICDAS clinical criteria on digital 3D models

OBJECTIVE

To assess the diagnostic validity of ICDAS clinical criteria on 3D dental models from intraoral scanning.

METHODS

This is a retrospective analysis on part of the baseline sample collected in a cohort study and included 73 participants (12-19 years) from Denmark and Greece. The assessment was made by visual inspection, and then by visual inspection associated with radiographs. All participants were scanned with TRIOS 4 which uses white light to obtain the 3D models with tooth color, as well as blue light source (415 nm) for fluorescence. The 3D models' evaluation was conducted using tooth-color texture and subsequently fluorescence. Two scores were obtained for the 3D model examination: i) ICDAS based on tooth-color information; ii) ICDAS based on tooth-color information supplemented with fluorescence. For the analysis, weighted kappa, sensitivity (SE), specificity (SP) and accuracy (ACC) were calculated.

RESULTS

Regarding all lesions the values for SE, SP, and ACC were respectively 0.804, 0.801, and 0.802 for tooth-color, and 0.819, 0.808, and 0.810 for tooth-color supplemented with fluorescence. In terms of accuracy parameters for moderate-extensive lesions, the values for SE, SP, and ACC for tooth color were 0.709, 0.948, and 0.944, while for fluorescence they were 0.815, 0.937, and 0.934.

CONCLUSION

Caries assessment with ICDAS criteria on 3D dental models produces reliable scores. Visual caries analysis using 3D models demonstrates commendable diagnostic accuracy and reasonable consistency with traditional methods. The use of intraoral scanners may be beneficial in evaluating occlusal caries.

CLINICAL SIGNIFICANCE

The importance of this study is to prove the diagnostic accuracy of caries lesions diagnosis made using and intraoral scanner and to offer greater confidence to professionals who use this diagnosis tool in their daily clinical practice. Intraoral scanners demonstrate to be an accurate tool for diagnosing occlusal caries.

Assessment of diagnostic accuracy and reliability of reveal fluorescence dental loupes in detecting molar incisor hypomineralization in children

BACKGROUND

Molar-Incisor Hypomineralization (MIH) poses challenges to accurate diagnosis, impacting children's oral health. Traditional methods exhibit limitations, necessitating innovative approaches. This study aimed to evaluate the reliability and diagnostic accuracy Reveal Fluorescence Dental Loupes (RFDLs) for the detection of MIH METHODS: This cross-sectional study, adhering to STRAD guidelines, involved 38 healthy children (age 7-9) with MIH. Ethical approval and informed consent were obtained. Microscope images and Reveal loupes were employed for examinations. Validity was assessed against microscope results, and inter- and intra-examiner reliability were measured using ICC and Kappa coefficients. Sensitivity, specificity, and overall accuracy were calculated, with an AUC-ROC analysis for discriminatory ability.

RESULTS

Intra-examiner reliability scores were excellent (Examiner 1: ICC 0.92, Examiner 2: ICC 0.94). Inter-examiner reliability (Kappa 0.92) indicated almost perfect agreement. Reveal demonstrated high sensitivity (82.61 %) and specificity (92.59 %), with an overall accuracy of 88.70 %. AUC-ROC analysis supported its robust discriminatory ability (AUC: 0.871).

CONCLUSIONS

Reveal Fluorescence Dental Loupes emerged as a promising diagnostic tool for accurate MIH detection, particularly in outreach settings. The study highlights the transformative impact of accessible and reliable diagnostic tools on pediatric oral health outcomes. While acknowledging limitations and the absence of a gold standard, the findings contribute to advancing MIH diagnostic capabilities. Further research in diverse populations is warranted for comprehensive validation.

Clinical evaluation of resin infiltration treatment masking effect on hypomineralised enamel surfaces

BACKGROUND

Resin infiltration is a micro-invasive treatment for molar incisor hypomineralisation (MIH). In this study it was aimed to evaluate the masking effect of resin infiltration treatment (ICON) on hypomineralised enamel surface of permanent anterior teeth by using laser fluorescence, spectrophotometer, and cross-polarisation photography.

METHODS

A total of 116 permanent central incisors in 37 patients were included in the study. The resin infiltration treatment (Icon®) was applied to the teeth with MIH; the healthy teeth received no treatment (control). Hypomineralised enamel lesions were evaluated by ICDAS II criteria. DIAGNOdent Pen was used to assess the lesions and healthy enamel surface quantitatively. Colour changes in enamel lesions were evaluated by using a spectrophotometer (VITA EasyShare). Each enamel lesion was imaged using a cross-polarization technique before and after treatment. All photos were assessed using Image J to evaluate the changes in lesion size. Enamel lesions were evaluated before; immediately after; 1; 3; and 6 months after treatment. Statistical significance was set as p < 0.05.

RESULTS

After the resin infiltration, significant decreases were found in the mean DIAGNOdent values for the treatment group (p < 0.05). The colour differences before and after treatment significantly differed in all follow-ups (p < 0.05). In the treatment group, lesion areas decreased significantly after treatment (p < 0.05).

CONCLUSIONS

The resin infiltration treatment has a masking effect on MIH lesions without cavities, with stable outcomes after six months. The cross-polarization photography technique may be use to evaluate the lesion size instead of photography with flash.

TRIAL REGISTRATION

NCT04685889 (registered 28 December 2020).

A case-controlled investigation of risk factors associated with molar incisor hypomineralization (MIH) in 8-12 year-old children living in Chandigarh, India

PURPOSE

Despite mounting evidence in favour of various perinatal risk factors for occurrence of MIH, verification of these remains doubtful because of lack of documented proof. The present study was aimed at examining the putative risk factors for MIH based on hospital-maintained records assessment.

METHODS

A total of 3176, 8-12 year-old children were screened for MIH using EAPD criteria (2003). Of these, risk factor analysis was carried out for 104 MIH affected and 211 non-MIH affected children with complete peri-natal medical records maintained up to 3 year post-birth. Chi-square test was used for risk factor comparison, while significance was assessed using logistic regression.

RESULTS

Prevalence of MIH in study population was 11.72% (372/3176). Various pre-natal, natal and post-natal risk factors including intra-uterine growth retardation (6.7 vs. 1.4%); maternal anaemia (10.6 vs. 3.8%) and neonatal jaundice (29.8 vs. 14.2%) were significantly higher in the MIH group. Furthermore, pre-term birth (OR 3.01), low birth weight (OR 2.37), more than three pyrogenic episodes (OR 7.61) and consumption of Amoxicillin Clavulanate (OR 3.01) were significantly associated with higher risk of developing MIH.

CONCLUSIONS

Pre and post-natal risk factors showed a moderate to high association for occurrence of MIH although social and nutritional factors had a lesser association.

Effects of different remineralization agents on MIH defects: a randomized clinical study

OBJECTIVES

The aim of this study was to present a comparative evaluation of the long-term efficacy of fluoride varnish and pastes containing CPP-ACP and CPP-ACP with fluoride (CPP-ACFP) in the remineralization of creamy-white and yellow-brown defects in permanent first molars with MIH.

MATERIALS AND METHODS

The study included 120 teeth with yellow-brown or creamy-white defects in 67 children (37 girls, 30 boys) aged 6-9 years (mean, 7.2) who were newly diagnosed with MIH with no substance loss or caries or prior restorative treatment. The patients were randomly divided into the experiment groups; control (oral hygiene motivation only), fluoride varnish, and pastes containing CPP-ACP and CPP-ACPF, and followed up for 24 months. The evaluations were made based on the ICDAS criteria and the measurements which were performed using the laser fluorescence method (DIAGNOdent, KaVo, Biberach, Germany) in the follow-ups.

RESULTS

The research was completed with 49 patients (23 females, 26 males; mean age, 7.7) and 90 teeth. All remineralization agents increased remineralization rates in both creamy-white and yellow-brown colored defects without presenting any statistically significant difference at the end of the follow-up period (p > 0.05). However, the effects of fluoride varnishes were late to observe when compared to pastes containing CPP-ACP and CPP-ACPF.

CONCLUSIONS

Pastes containing calcium and phosphate may be recommended for the longer-term preservation of teeth with yellow-brown defects which showed a post-eruptive breakdown in a shorter time.

CLINICAL RELEVANCE

There is a lack of studies investigating MIH treatments in which lesion appearance was recorded. This study evaluated creamy-white and yellow-brown MIH defects separately and reported long-term results of different remineralization agents.

Diagnodent and VistaCam may be unsuitable for the evaluation of dental caries in archeological teeth

OBJECTIVES

The aim of the study was to compare the usefulness of fluorescence-based caries detection systems (Diagnodent and VistaCam) for the assessment of carious lesions on archeological molars.

MATERIALS AND METHODS

The study material consisted of teeth from the Cemetery of St. Mary Magdalene (Cmentarz św. Marii Magdaleny) in Wrocław, Poland. A sample of 178 permanent molars from 38 skulls were examined. Five surfaces of teeth (occlusal, mesial, distal, buccal, and lingual) were assessed on either basically cleaned or sandblasted teeth. Six diagnostic methods were used to detect carious lesions: the visual classification of the International Caries Detection and Assessment System (ICDAS II), fluorescent methods (Diagnodent and VistaCam), X-ray, cone beam computed tomography and histological sections. The sensitivity and specificity of the methods were determined using receiver operating characteristic (ROC) curves and the correlation between the severity of dental caries and the readouts obtained with each method.

RESULTS

In most cases, Diagnodent and VistaCam yielded unsatisfactory specificity and sensitivity values. The area under curve (AUC) values in ROC curves for Diagnodent and Vistacam were lower than the AUC values obtained for the ICDAS II visual classification.

CONCLUSIONS

According to our results, in the case of archeological teeth, neither Diagnodent nor VistaCam can be regarded as a better diagnostic method than the ICDAS II visual classification of caries.

Detection of proximal caries using quantitative light-induced fluorescence-digital and laser fluorescence: a comparative study

PURPOSE

The purpose of this study was to evaluate the in vitro validity of quantitative light-induced fluorescence-digital (QLF-D) and laser fluorescence (DIAGNOdent) for assessing proximal caries in extracted premolars, using digital radiography as reference method.

MATERIALS AND METHODS

A total of 102 extracted premolars with similar lengths and shapes were used. A single operator conducted all the examinations using three different detection methods (bitewing radiography, QLF-D, and DIAGNOdent). The bitewing x-ray scale, QLF-D fluorescence loss (ΔF), and DIAGNOdent peak readings were compared and statistically analyzed.

RESULTS

Each method showed an excellent reliability. The correlation coefficient between bitewing radiography and QLF-D, DIAGNOdent were -0.644 and 0.448, respectively, while the value between QLF-D and DIAGNOdent was -0.382. The kappa statistics for bitewing radiography and QLF-D had a higher diagnosis consensus than those for bitewing radiography and DIAGNOdent. The QLF-D was moderately to highly accurate (AUC = 0.753 - 0.908), while DIAGNOdent was moderately to less accurate (AUC = 0.622 - 0.784). All detection methods showed statistically significant correlation and high correlation between the bitewing radiography and QLF-D.

CONCLUSION

QLF-D was found to be a valid and reliable alternative diagnostic method to digital bitewing radiography for in vitro detection of proximal caries.

New Insights into Effects of Aromatic Amino Acids on Hydroxyapatite

Biomimetics inspired by superstructures and extraordinary properties of teeth have resulted in tooth repair and the generation of novel materials. However, little attention has been paid to tooth color, whose origin remains unknown. Based on recent studies, fluorophores-mainly aromatic amino acids (AAAs) in proteins-might be responsible for tooth color. We synthesized carbonated hydroxyapatite (HA; the mineral phase of teeth) in the presence of different amino acids (AAs; the basic units of protein matrix of teeth) as a simplified model of teeth to explore the color source at the AA level. After measuring the fluorescence and color characteristics of HA-AAs before and after bleaching treatment, we found that only HA, synthesized in the presence of AAAs, exhibited remarkable fluorescence and color property. Furthermore, linearly increased fluorescence intensity and deeper color were observed with an increase in AAA content in HA-AAAs. Similarly, significantly decreased absorbance of HA-AAAs between 250 and 300 nm in ultraviolet spectra, declined fluorescence intensity, and decolored performance of HA-AAAs were observed after bleaching treatment. The results showed that AAAs contributed to the fluorescence and color properties of HA and that hydrogen peroxide might whiten HA-AAAs by oxidizing the benzene ring in AAAs. These findings are of great significance in promoting the synthesis of advanced tooth-colored materials and furthering our understanding of the possible mechanisms of hydrogen peroxide. Moreover, our study shed light on the importance of AAAs and might provide new ideas for investigations of biomineralization and biomimetics.

An investigation into the effect of a resin infiltrant on the micromechanical properties of hypomineralised enamel

BACKGROUND

Resin infiltration may alter the mechanical properties of enamel hypomineralised lesions (HL); however, variable surface layer (SL) thickness may affect resin penetration.

AIMS

To determine the thickness of the SL of HL and to investigate the effect of resin infiltration on the mechanical properties of HL.

DESIGN

The thickness of the SL over HL was determined using polarised light microscopy. Etching time using 15% HCl gel to remove the SL of 52 samples was determined. Selected HL and control areas of 21 teeth were infiltrated with Icon^® resin infiltrant, and cross-sectional Knoop microhardness (KHN) measurements were recorded before and after resin infiltration.

RESULTS

Ninety-six point five per cent of HL had a detectable SL with mean thickness of 58 ± 29 μm. Application of HCl for 120 s produced a mean MIH erosion depth of 58 ± 12 μm. Eleven of 21 samples had evidence of infiltration using visual examination. The infiltrant penetrated some of the HL leading to an increase in KHN (111 ± 75 KHN) which, when compared to adjacent non-infiltrated HL (96 ± 52 KHN), was not statistically significantly different (P = 0.56).

CONCLUSIONS

There was marked variation in the SL thickness of HL. Resin infiltration of HL did not increase microhardness significantly.

Cut off values of laser fluorescence for different storage methods at different time intervals in comparison to frozen condition: A 1 year in vitro study

Aims:

The aim of the following study is to evaluate the change in laser fluorescence (LF) values for extracted teeth stored in different solutions over 1 year period, to give cut-off values for different storage media at different time intervals to get them at par with the in vivo conditions and to see which medium gives best results with the least change in LF values and while enhancing the validity of DIAGNOdent in research.

Materials and Methods:

Ninety extracted teeth selected, from a pool of frozen teeth, were divided into nine groups of 10 each. Specimens in Groups 1-8 were stored in 1% chloramine, 10% formalin, 10% buffered formalin, 0.02% thymol, 0.12% chlorhexidine, 3% sodium hypochlorite, a commercially available saliva substitute-Wet Mouth (ICPA Pharmaceuticals) and normal saline respectively at 4°C. The last group was stored under frozen condition at −20°C without contact with any storage solution. DIAGNOdent was used to measure the change the LF values at day 30, 45, 60, 160 and 365.

Statistical Analysis Used:

The mean change in LF values in different storage mediums at different time intervals were compared using two-way ANOVA.

Results:

At the end of 1 year, significant decrease in fluorescence (P < 0.05) was observed in Groups 1-8. Maximum drop in LF values occurred between day 1 and 30. Group 9 (frozen specimens) did not significantly change their fluorescence response.

Conclusions:

An inevitable change in LF takes place due to various storage media commonly used in dental research at different time intervals. The values obtained from our study can remove the bias caused by the storage media and the values of LF thus obtained can hence be conveniently extrapolated to the in vivo condition.

Can the individual calibration be modified when laser fluorescence method is used for caries detection?

BACKGROUND

Individual calibration (IC) for caries detection methods based on fluorescence is time-consuming, especially for paediatric dentists, if the calibration has to be performed tooth-by-tooth. However, it is not clear how this calibration actually interfere in laser fluorescence (LF) readings.

AIM

This in vivo study was to verify the influence of different modes of IC on laser fluorescence (LF) readings.

DESIGN

Ninety six occlusal and 95 buccal surfaces of 1st permanent molars were examined using LF device after IC performed on control (no IC), the examined teeth, a permanent incisor, a 1st primary molar or a 2nd primary molar. All modes of IC were performed in the same child. Wilcoxon test and Bland-Altman analysis were used to compare the readings. Intraclass correlation coefficients (ICC) were calculated.

RESULTS

Laser fluorescence readings without prior calibration were higher than readings performed after any mode of IC and resulted in different values of ICC. After other IC modes, the LF readings were statistically similar.

CONCLUSION

The absence of IC influences LF readings and LF reproducibility, but different IC methods can be considered in clinical practice.

A novel LED-based device for occlusal caries detection

The aim of this in-vitro study was to compare the performance of laser-based (DIAGNOdent, KaVo, Biberach, Germany) and LED-based (Midwest Caries I.D., DENTSPLY Professional, New York, USA) caries detectors in the detection of occlusal caries in permanent molars. The study consisted of 129 visually sound or non-cavitated pits or fissures in 82 extracted permanent human molar teeth. Two trained examiners used the laser-based and LED-based caries detectors to examine the fissures for caries. The teeth were then sectioned at the surfaces suspected of containing occlusal caries and histologically evaluated using stereomicroscopy as a gold standard. Inter-examiner reliability of the caries detector examination was assessed using Cohen's Kappa statistics. The sensitivity, specificity, and accuracy in diagnosing occlusal caries using the two devices were calculated according to appropriate cut-off scores. Receiver operating characteristic (ROC) curves were also determined to compare the diagnostic performance of the devices in occlusal caries diagnosis. The cut-off level of significance was taken as p = 0.005. Cohen's Kappa showed substantial agreement for the laser-based caries detector (0.74), and almost perfect agreement for the LED-based (0.89) caries detector. The specificity of the laser-based device varied from 0.49 to 0.97 at T1 and T2. Its sensitivity varied from 0.33 to 0.65 at T1 and T2. The specificity of the LED-based device varied from 0.48 to 0.56 at T1 and T2. Its sensitivity varied from 0.65 to 0.84 at T1 and from 0.80 to 0.84 at T2. Taking the limitations of the current study into consideration, the DIAGNOdent laser pen was more accurate in determining when teeth were free of occlusal caries than was the Midwest Caries I.D. LED-based device, although the Midwest Caries I.D. device more often revealed the presence of occlusal caries than did the DIAGNOdent pen.

Linking the clinical presentation of molar-incisor hypomineralisation to its mineral density

BACKGROUND

The in vitro methods used for the assessment of the severity of molar-incisor hypomineralisation (MIH) are not available for clinicians faced with questions regarding the severity in clinical cases, and the best management approach.

AIM

To assess whether there is a relation between the severity of the defects in MIH enamel (represented by reduction in the mineral density) and the clinical presentation (represented by the colour of the defect and its laser fluorescence).

DESIGN

The colour of enamel was recorded (normal, white, yellow or brown) in specific areas for ten extracted first permanent molars with MIH defects and ten extracted sound teeth. Laser fluorescence (LF) and mineral density (MD) were measured for the same areas. A mixed model, using sample/tooth as a random effect, was used to estimate the relationship between the MD and the colour-coding, and between the MD and LF readings.

RESULTS

The between-samples correlation coefficient for the colour coding and the MD was 0.99 (P < 0.001), and 0.83 (P < 0.001) for the LF and MD.

CONCLUSIONS

The degree of staining of MIH enamel, as assessed visually or by LF, may be used clinically to reflect the severity of the defect.

Protein content of molar-incisor hypomineralisation enamel

OBJECTIVES

The aim of the study was to compare the relative amounts and nature of the proteinous content of sound and molar-incisor hypomineralisation (MIH) enamel.

METHODS

TCA (20%) was used to dissolve the mineral phase and precipitate the proteins from enamel pieces sectioned from sound and MIH enamel. The protein content was estimated using a miniaturized version of the method of Lowry et al. Samples of the solubilised protein were separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), stained with Coomassie Blue R250 and tryptic fingerprint/mass spectrometry (MS/MS) of bands in excised gel pieces used for protein identification.

RESULTS

Compared to sound enamel, brown enamel showed a 15-21-fold higher protein content, and yellow and chalky enamel showed about 8-fold higher protein content. Tryptic fingerprint/MS performed on excised 50-70kDa areas demonstrated serum albumin, type I collagen and antitrypsin to be common to all types of enamel. Yellow and brown enamel showed more abundant serum albumin and antitrypsin, and the presence of serum antithrombin. Albumin is reported to be an inhibitor of crystal growth, and antitrypsin and antithrombin inhibit kallikrein 4 proteolytic activity.

CONCLUSIONS

The combination of the effects of serum proteins on developing enamel may result in elevated proteinous content and reduced mineral content as seen in MIH enamel.

DIAGNOdent measurements of cultures of selected oral bacteria and demineralized enamel

OBJECTIVE

Carious tissue fluoresces with a wavelength different from sound tissue when stimulated by light with a wavelength of 655 nm. This difference is thought to have a bacterial origin rather than indicating demineralization. This study aimed to measure fluorescence emitted by normal cultivable caries-associated bacterial flora and typical porphyrin-producing bacteria with DIAGNOdent, and to verify earlier findings that demineralization of the dental hard tissue does not affect DIAGNOdent readings.

MATERIAL AND METHODS

Bacterial samples were collected from five occlusal caries lesions in three subjects. From these, mixed anaerobic flora, Lactobacilli and mutans Streptococci were cultured in up to three different kinds of culture medium. Colonies of Lactobacilli and mutans Streptococci were also measured after transferring them to glass slides. Laboratory teaching strains of Prevotella spp., Porphyromonas gingivalis and Actinomyces odontolyticus were cultured anaerobically and fluorescence measured directly after an appropriate incubation period. Sound enamel surfaces of 15 extracted premolars were demineralized and changes in fluorescence measured.

RESULTS

DIAGNOdent readings > 20 were only obtained from young colonies of Prevotella and from colonies of mutans Streptococci cultured on mitis-salivarius-bacitracin agar. Higher measurements were obtained as the bacterial colonies aged. Lower measurements were obtained after transferring colonies to glass slides. Demineralization of enamel did not affect the DIAGNOdent measurements.

CONCLUSIONS

The change in fluorescence measured with DIAGNOdent has a bacterial origin rather than occurring as a result of demineralization. The measurements are presumably dependent on bacterial metabolites rather than bacteria themselves, and probably record synergistic effects during the carious process rather than the quantity or species of bacteria involved.

Mineral density of hypomineralised enamel

OBJECTIVES

To characterize molar-incisor hypomineralisation (MIH) defects of different severities quantitatively and qualitatively using X-ray microtomography (XMT) and to measure the range of reduction in mineral density (MD) of MIH enamel compared with the normal range.

METHODS

Ten sound teeth and ten MIH teeth were scanned using a commercial XMT system. Four hydroxyapatite phantoms of different densities were used as calibration standards with each scan. A calibration equation derived from the phantoms with each tooth was used for MD calibration. MD was traced from the cementum-enamel junction (CEJ) to the cusp tip and from the dentine-enamel junction (DEJ) to the outer enamel surface.

RESULTS

In sound teeth, MD increased from CEJ to cusp/incisal tip, while in MIH teeth MD dropped from the CEJ to the occlusal region, then increased again at the cusp tip. MD was highest midway between DEJ and outer enamel in sound teeth. In MIH, enamel showed normal thickness and MD was highest near the DEJ and then decreased towards the outer enamel. MD of MIH enamel was on average about 19% lower than sound enamel. The MIH defects seemed to follow the incremental lines of enamel formation.

CONCLUSIONS

MIH defects are hypomineralised defects of different severities that follow the natural incremental lines of enamel formation. Cuspal areas are usually only mildly affected and cervical enamel always appears to be sound.