Changes In Enamel Research Articles

Precision of 655 nm Confocal Laser Profilometry for 3D surface texture characterisation of natural human enamel undergoing dietary acid mediated erosive wear

ObjectivesTo assess the precision of optical profilometry for characterising the 3D surface roughness of natural and polished human enamel in order to reliably quantify acid mediated surface roughness changes in human enamel. MethodsForty-two enamel samples were prepared from extracted human molars and either polished flat or left unmodified. To investigate precision, the variability of thirty repeated measurements of five areas of one polished and one natural enamel sample was assessed using 655nm Confocal Laser Profilometry. Remaining samples were subjected to forty-five minutes orange juice erosion and microstructural changes were analysed using Sa roughness change (μm) and qualitatively using surface/subsurface confocal microscopy. ResultsEnamel surface profilometry from the selected areas revealed maximal precision of 5nm for polished enamel and 23nm for natural enamel. After erosion, the polished enamel revealed a 48% increase in mean (SD) Sa roughness of 0.10 (0.07)μm (P<0.05), whereas in contrast the natural enamel revealed a 45% decrease in mean (SD) roughness of −0.32 (0.42)μm (P<0.05). These data were supported by qualitative confocal images of the surface/subsurface enamel. SignificanceThis study demonstrates a method for precise surface texture measurement of natural human enamel. Measurement precision was superior for polished flat enamel in contrast to natural enamel however, natural enamel responds very differently to polished enamel when exposed to erosion challenges. Therefore, thus future studies characterising enamel surface changes following erosion on natural enamel may provide more clinically relevant responses in comparison to polished enamel.

Effects of repeated bracket bonding on enamel color changes.

The objective of the study is to evaluate the effects of repeated bracket bonding on the color changes of tooth enamel after in vitro coloration. Eighty-one premolars were equally divided into three groups. Samples in Group 1 (G1) represented nonorthodontic treatment patients, and the enamel surfaces were left intact. Samples in Group 2 (G2) and Group 3 (G3) represented orthodontic treatment patients with no repeated bonding and brackets bonded 3 times, respectively. After the brackets were bonded in G2 and G3, samples in all groups were kept in four different staining solutions for 96 h and received 24 h of photoaging. This cycle was repeated 3 times. Brackets were debonded and rebonded in G3 samples after each cycle, whereas brackets were only debonded once in G2 samples after the third cycle. The color changes were assessed using a spectrophotometer at baseline (T1) and after removing the brackets and cleaning the enamel surface (T2). Data (ΔE) were analyzed statistically with analysis of variance between groups, and with Paired t-test within groups. Although the color changes for G1, G2, and G3 were significant (P < 0.05) within groups; the difference was similar between groups (P > 0.05). Repeated bracket bonding does not have a negative influence on the enamel color change after in vitro coloration when compared with intact enamel surface and single bonding.

Hypercementosis Associated with ENPP1 Mutations and GACI

Mineralization of bones and teeth is tightly regulated by levels of extracellular inorganic phosphate (Pi) and pyrophosphate (PPi). Three regulators that control pericellular concentrations of Pi and PPi include tissue-nonspecific alkaline phosphatase (TNAP), progressive ankylosis protein (ANK), and ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1). Inactivation of these factors results in mineralization disorders affecting teeth and their supporting structures. This study for the first time analyzed the effect of decreased PPi on dental development in individuals with generalized arterial calcification of infancy (GACI) due to loss-of-function mutations in the ENPP1 gene. Four of the 5 subjects reported a history of infraocclusion, overretained primary teeth, ankylosis, and/or slow orthodontic tooth movement, suggesting altered mineral metabolism contributing to disrupted tooth movement and exfoliation. All subjects had radiographic evidence of unusually protruding cervical root morphology in primary and/or secondary dentitions. High-resolution micro–computed tomography (micro-CT) analyses of extracted primary teeth from 3 GACI subjects revealed 4-fold increased cervical cementum thickness (P = 0.00007) and a 23% increase in cementum density (P = 0.009) compared to age-matched healthy control teeth. There were no differences in enamel and dentin densities between GACI and control teeth. Histology revealed dramatically expanded cervical cementum in GACI teeth, including cementocyte-like cells and unusual patterns of cementum resorption and repair. Micro-CT analysis of Enpp1 mutant mouse molars revealed 4-fold increased acellular cementum thickness (P = 0.002) and 5-fold increased cementum volume (P = 0.002), with no changes in enamel or dentin. Immunohistochemistry identified elevated ENPP1 expression in cementoblasts of human and mouse control teeth. Collectively, these findings reveal a novel dental phenotype in GACI and identify ENPP1 genetic mutations associated with hypercementosis. The sensitivity of cementum to reduced PPi levels in both human and mouse teeth establishes this as a well-conserved and fundamental biological process directing cementogenesis across species (ClinicalTrials.gov NCT00369421).

Effect of dentifrice containing fTCP, CPP-ACP and fluoride in the prevention of enamel demineralization

Objective: To evaluate the effect of different fluoride- and calcium- and/or phosphate-containing products on their ability to prevent enamel demineralization under pH cycling conditions.Material and methods: Enamel bovine specimens were assigned to the following groups: G1-MPP (MI Paste Plus, 0.2% NaF, Recaldent™, GC Corporation Tokyo, Japan); G2-FD (Crest™ Cavity Protection, 0.243% NaF, Procter & Gamble, USA); G3-CLP (Clinpro™ 5000, 1.1% NaF, 3M ESPE, USA); and G4-CO (Control without fluoride, Silica-based dentifrice; Daudt Ltda, Brazil). The specimens were soaked in demineralizing solution for 6 h and remineralizing solution for 18 h alternatively for 10 days. The toothpaste was prepared with deionized water in a 1:3 ratio (w/v) for three minutes daily. The solutions were renewed every 48 h. After cycling, enamel changes were analysed by percentage change of SMH (%SMH) and energy-dispersive X-ray spectroscopy (EDS). The %SMH value observed for G3-CLP (2.9 ± 39.2) was higher than that found in G4-CO (−13.0 ± 20.7), G1-MPP (−8.9 ± 20.9) and G2-FD (−3.9 ± 27.1). The %SMH was similar for all treatment groups (one-way ANOVA and Tukey’s HSD; p < .05). The pH, Ca2+ and Ptotal in the remineralization solutions were not different among all groups (Kruskal–Wallis; p < .05). At 24 h, the Ca2+ concentration in the demineralization solution was significantly lower in G1-MPP. Ca2+ concentration increased in all groups after 48 h, except for G3-CLP. The EDX quantitative analysis showed that the atomic % of elements is lower level at G4-CO.Conclusions: The Clinpro™ 5000 demonstrated having the most protective effect against demineralization; however, the % SMH was similar for all groups.

Oral cancer radiotherapy affects enamel microhardness and associated indentation pattern morphology.

The aim of this study is to determine the effects of in vitro and in vivo high-dose radiotherapy on microhardness and associated indentation pattern morphology of enamel. The inner, middle, and outer microhardness of enamel was evaluated using three experimental groups: control (non-radiated); in vitro irradiated; in vivo irradiated. In vitro specimens were exposed to simulated radiotherapy, and in vivo specimens were extracted teeth from oral cancer patients previously treated with radiotherapy. Indentations were measured via SEM images to calculate microhardness values and to assess the mechanomorphological properties of enamel before and after radiotherapy. Middle and outer regions of enamel demonstrated a significant decrease in microhardness after in vitro and in vivo irradiation compared to the control group (p < 0.05). Two indentation patterns were observed: pattern A-presence of microcracks around indent periphery, which represents local dissipation of deformation energy; pattern B-clean, sharp indents. The percentage of clean microindentation patterns, compared to controls, was significantly higher following in vitro and in vivo irradiation in all enamel regions. The highest percentage of clean microindentations (65%) was observed in the in vivo irradiated group in the inner region of enamel near the dentin-enamel junction. For the first time, this study shows that in vitro and in vivo irradiation alters enamel microhardness. Likewise, the indentation pattern differences suggest that enamel may become more brittle following in vitro and in vivo irradiation. The mechanomorphological property changes of enamel following radiation may be a contributory component of pathologic enamel delamination following oral cancer radiotherapy.

The effect of magnesium hydroxide-containing dentifrice using an extrinsic and intrinsic erosion cycling model

ObjectiveTo evaluate, in vitro, the effect of Mg(OH)2 dentifrice, and the influence of the number of experimental days, on the extrinsic (citric acid –CA) and intrinsic (hydrochloric acid –HCl) enamel erosion models. DesignHuman enamel slabs were selected according to surface hardness and randomly assigned to 3 groups (n=9) as follows: non-fluoridated (negative control), NaF (1450ppm F- positive control) and Mg(OH)2 (2%) dentifrices. The slabs were daily submitted to a 2-h period of pellicle formation and, over a period of 5days, submitted to cycles (3×/day) of erosive challenge (CA 0.05M, pH=3.75 or HCl 0.01M, pH=2 for 30s), treatment (1min −1:3w/w of dentifrice/distilled water) and remineralization (artificial saliva/120min). Enamel changes were determined by surface hardness loss (SHL) for each day and mechanical profilometry analysis. Data were analyzed by two-way ANOVA followed by Tukey’s test to % SHL and one-way ANOVA to profilometry (p<0.05). ResultsThe number of experimental days influenced the erosion process for the two types of erosion models (p<0.001). Mg(OH)2-containing dentifrices were effective in reducing enamel extrinsic acid erosion as determined by % SHL (p<0.001) when compared to the control group, being better than positive control (p<0.001); however, the dentifrices were not effective for the intrinsic model (p=0.295). With regards to surface wear, no statistically significant differences were found among the groups for CA (p=0.225) and HCl (p=0.526). ConclusionThe findings suggest that Mg(OH)2 dentifrices might protect enamel against slight erosion, but protection was not effective for stronger acid erosion.

Comparison of Enamel Color Alterations Associated with Different Staining Agents around Orthodontic Brackets: An In vitro Study

Objective: Color of natural teeth changes after orthodontic treatment. The aim of the study was to evaluate color changes of enamel before and after fixed mechanotherapy and compare the effects of different staining agents on enamel discoloration. Materials and Methods: Hundred freshly extracted premolars were divided into four groups of n = 25 each. Baseline color measurements were taken before bonding through reflectance spectrophotometer (X-Rite i1Pro). Postbonding samples were suspended in test solutions; Group 1 (control group) samples stored in distilled water and Group 2, 3, and 4 in tea, coffee, and turmeric solutions, respectively for a week. The samples were then debonded and cleaned with eight fluted tungsten carbide bur followed by pumicing. Color evaluations were made in accordance with Commission Internationale de l'Eclairage L* a* b color system. ΔE values were compared for samples before and after debonding. Results: Mean ΔE difference value was found maximum for Group 3 (mean 12.4560, standard deviation [SD] 4.7207) and minimum for Group 1 (mean 9.7120 SD 4.2009). One-way ANOVA was used for intergroup comparison with P Conclusion: Orthodontic bonding and debonding procedures have an effect on enamel discoloration clinically, although various stains used in the study had no statistical significant difference among themselves.

Measurement of surface roughness changes of unpolished and polished enamel following erosion

ObjectivesTo determine if Sa roughness data from measuring one central location of unpolished and polished enamel were representative of the overall surfaces before and after erosion.MethodsTwenty human enamel sections (4x4 mm) were embedded in bis-acryl composite and randomised to either a native or polishing enamel preparation protocol. Enamel samples were subjected to an acid challenge (15 minutes 100 mL orange juice, pH 3.2, titratable acidity 41.3mmol OH/L, 62.5 rpm agitation, repeated for three cycles). Median (IQR) surface roughness [Sa] was measured at baseline and after erosion from both a centralised cluster and four peripheral clusters. Within each cluster, five smaller areas (0.04 mm2) provided the Sa roughness data.ResultsFor both unpolished and polished enamel samples there were no significant differences between measuring one central cluster or four peripheral clusters, before and after erosion. For unpolished enamel the single central cluster had a median (IQR) Sa roughness of 1.45 (2.58) μm and the four peripheral clusters had a median (IQR) of 1.32 (4.86) μm before erosion; after erosion there were statistically significant reductions to 0.38 (0.35) μm and 0.34 (0.49) μm respectively (p<0.0001). Polished enamel had a median (IQR) Sa roughness 0.04 (0.17) μm for the single central cluster and 0.05 (0.15) μm for the four peripheral clusters which statistically significantly increased after erosion to 0.27 (0.08) μm for both (p<0.0001).ConclusionMeasuring one central cluster of unpolished and polished enamel was representative of the overall enamel surface roughness, before and after erosion.

Surface changes of enamel after brushing with charcoal toothpaste

The aim of this study was to determine the surface roughness changes of tooth enamel after brushing with charcoal toothpaste. Thirty specimens were brushed using distilled water (the first group), Strong® Formula toothpaste (the second group), and Charcoal® Formula toothpaste for four minutes and 40 seconds (equivalent to one month) and for 14 minutes (equivalent to three months) using a soft fleece toothbrush with a mass of 150 gr. The roughness was measured using a surface roughness tester, and the results were tested with repeated ANOVA test and one-way ANOVA. The value of the surface roughness of tooth enamel was significantly different (p<0.05) after brushing for an equivalent of one month and an equivalent of three months. Using toothpaste containing charcoal can increase the surface roughness of tooth enamel.

Quantitative Swept-Source Optical Coherence Tomography of Early Enamel Erosion in vivo

Swept-source optical coherence tomography (SS-OCT) shows potential for the in vivo quantitative evaluation of micro-structural enamel surface phenomena occurring during early erosive demineralization. This randomized controlled single-blind cross-over clinical study aimed to evaluate the use of SS-OCT for detecting optical changes in the enamel of 30 healthy volunteers subjected to orange juice rinsing (erosive challenge) in comparison to mineral water rinsing (control), according to wiped and non-wiped enamel surface states. Participants were randomly allocated to 60 min of orange juice rinsing (pH 3.8) followed by 60 min of water rinsing (pH 6.7) and vice versa, with a 2-week wash-out period. In addition, the labial surfaces of the right or left maxillary incisors were wiped prior to SS-OCT imaging. An automated ImageJ algorithm was designed to analyse the back-scattered OCT signal intensity (D) after orange juice rinsing compared to after water rinsing. D was quantified as the OCT signal scattering from the 33 µm sub-surface enamel, normalised by the total OCT signal intensity entering the enamel. The back-scattered OCT signal intensity increased by 3.1% (95% CI 1.1-5.1%) in the wiped incisors and by 3.5% (95% CI 1.5-5.5%) in the unwiped incisors (p < 0.0001). Wiping reduced the back-scattered OCT signal intensity by 1.7% (95% CI -3.2 to -0.3%; p = 0.02) in comparison to the unwiped enamel surfaces for both rinsing solutions (p = 0.2). SS-OCT detected OCT signal changes in the superficial sub-surface enamel of maxillary central incisor teeth of healthy volunteers after orange juice rinsing.

Measurement uncertainty associated with chromatic confocal profilometry for 3D surface texture characterization of natural human enamel

ObjectiveTo investigate the measurement performance of a chromatic confocal profilometer for quantification of surface texture of natural human enamel in vitro. MethodsContributions to the measurement uncertainty from all potential sources of measurement error using a chromatic confocal profilometer and surface metrology software were quantified using a series of surface metrology calibration artifacts and pre-worn enamel samples. The 3D surface texture analysis protocol was optimized across 0.04mm2 of natural and unpolished enamel undergoing dietary acid erosion (pH 3.2, titratable acidity 41.3mmolOH/L). ResultsFlatness deviations due to the x, y stage mechanical movement were the major contribution to the measurement uncertainty; with maximum Sz flatness errors of 0.49μm. Whereas measurement noise; non-linearity’s in x, y, z and enamel sample dimensional instability contributed minimal errors. The measurement errors were propagated into an uncertainty budget following a Type B uncertainty evaluation in order to calculate the Standard Combined Uncertainty (uc), which was ±0.28μm. Statistically significant increases in the median (IQR) roughness (Sa) of the polished samples occurred after 15 (+0.17 (0.13)μm), 30 (+0.12 (0.09)μm) and 45 (+0.18 (0.15)μm) min of erosion (P<0.001 vs. baseline). In contrast, natural unpolished enamel samples revealed a statistically significant decrease in Sa roughness of −0.14 (0.34) μm only after 45min erosion (P<0.05s vs. baseline). SignificanceThe main contribution to measurement uncertainty using chromatic confocal profilometry was from flatness deviations however by optimizing measurement protocols the profilometer successfully characterized surface texture changes in enamel from erosive wear in vitro.

Evaluation of CPP-ACP and Fluoride on Inhibition of Human Enamel demineralisation: Cross-sectional Hardness and MicroCT Studies.

To evaluate the in vitro effect of different application frequencies of dentifrices containing CPP-ACP and fluoride on enamel demineralisation inhibition using a pH cycling model. One hundred twenty blocks of human enamel were divided into 8 groups according to the treatment and number of times that the dentifrice slurry was applied (3 or 5 times). dentifrice without fluoride (CO3 and CO5); fluoride dentifrice (FD3 and FD5, commercial dentifrice 1100 ppm as NaF); MI Paste (MP3 and MP5, Recaldent) and MI Paste Plus (MPP3 and MPP5, Recaldent 900 ppm as NaF). After pH cycling, cross-sectional microhardness (CSH) measurements were taken. The demineralised enamel changes were analyzed on three blocks per group by MicroCT. Data were analyzed by ANOVA and Tukey's HSD post-hoc test (p = 0.05). Statistically significantly higher CSH values (p < 0.05) were obtained for the surface layers (25 and 50 µm) for FD3, FD5, MP3 and MP5. The MP and FD groups showed similar results and had the least mineral loss. The MP increased the mineral density in enamel and decreased the depth of the lesion. Inhibition of subsurface enamel demineralisation is possible with MP and FD, independent of the application frequencies. However, the MP and MPP groups had higher mineral density when five applications were performed.

種々のエネルギー密度でCO2レーザー (波長9.3μmおよび10.6μm) 照射したエナメル質の形態の変化

種々のエネルギー密度でCO2レーザー (波長9.3μmおよび10.6μm) 照射したエナメル質の形態の変化

Quantitative evaluation of the enamel caries which were treated with casein phosphopeptide-amorphous calcium fluoride phosphate.

The aim of this in vivo study was to quantitatively evaluate the remineralization of the enamel caries on smooth and occlusal surfaces using DIAGNOdent, after daily application of casein phosphopeptide-amorphous calcium fluoride phosphate (CPP-ACFP). Thirty volunteers, aged 18-30 years, with white spot lesions on the smooth and occlusal surfaces of the teeth were included in the study. These white spot lesions were visually examined and the degree of demineralization was quantitatively evaluated using DIAGNOdent. Volunteers with lesions scored as enamel caries on smooth surfaces (n = 109) and on occlusal surfaces (n = 176) were randomly divided into control and study groups. Both groups were instructed regarding oral hygiene and were asked to brush their teeth with the same tooth paste and tooth brush. In the study group, CPP-ACFP was applied daily for 4 min on the existing enamel caries lesions. After 4 weeks, the mineralization changes in enamel caries on the smooth and occlusal surfaces were assessed by DIAGNOdent. Recorded data were statistically analyzed by Wilcoxon signed-rank test and Mann-Whitney U-test. Comparison of DIAGNOdent values evaluated before and after the application of CPP-ACFP showed that the remineralization of enamel caries lesions on smooth and occlusal surfaces occurred in the study group (both, P < 0.001). The control group showed no quantitative changes at the end of 4 weeks (P > 0.05). At the end of the study period, the DIAGNOdent values differed significantly between the control and study groups (P < 0.001). Daily local application of CPP-ACFP for 4 min for 4 weeks results in significant remineralization of the initial caries lesions. CPP-ACFP can be used in the treatment of white spot lesions.

Ultrastructural changes of human dental hard tissues during orthodontic treatment with fixed appliances

The aim of the study was to evaluate ultrastructural changes of dental enamel after fixation of orthodontic appliances, initial influence of orthodontic forces and removal of braces. Five intact permanent tooth extracted for orthodontic reasons were included in the experimental study. Scanning probe microscopy was conducted in 4 random enamel points in each tooth (20 points overall) in semi-contact mode with standard 10 nm probes. The study showed ultrastructural enamel changes such as nanofractures up to 1 mm along the braces locks. The changes correlated with surface morphological features and teeth anatomy and may play an important role in dental decay and non-carious lesions occurring in the course of orthodontic treatment.

Surface changes of primary tooth enamel by commonly used pediatric liquid medicaments: A scanning electron microscope study

The present in-vitro study was conducted in primary teeth in order to evaluate the erosive potential of eight commonly used pediatric liquid medications (PLMs) using scanning electron microscope. 8 most commonly used Pediatric Liquid Medicaments and 27 extracted teeth that were near to exfoliation were collected. The endogenous pH of all the Pediatric Liquid Medications was measured using a pH electrode meter. The 27 teeth were divided into two groups, the control group (n = 3) and the study group (n = 24). Three teeth in Control group were immersed in artificial saliva for three different time intervals 1 min, 10 mins. and 8 hours. In experimental group, 24 teeth were also maintained for 1 min., 10 min. and 8 hours in 8 different pediatric liquid medicaments with 3 teeth in each medicine for three different time intervals. For all the teeth of both groups ,the primary enamel surface changes were then observed under Scanning electron microscope. When viewed under Scanning Electron Microscope, all the PLM's showed an erosive effect on the Primary Enamel Surface. Crater formation was found with most of the medications followed by etched prism pattern and sporadic rod ends. Acidic pH was seen with most of the pediatric liquid medicaments used in this study which causes dental erosion. Dental erosion eventually predisposes to dental caries, so it is important to educate professionals and parents regarding use of Pediatric Liquid Medicaments in children.

Effect of vital bleaching with solutions containing different concentrations of hydrogen peroxide and pineapple extract as an additive on human enamel using reflectance spectrophotometer: An in vitro study

Aim:This study aims to evaluate the color change in human enamel bleached with three different concentrations of hydrogen peroxide, containing pineapple extract as an additive in two different timings, using reflectance spectrophotometer.Background:The study aimed to investigate the bleaching efficacy on natural teeth using natural enzymes.Materials and Methods:Baseline color values of 10 randomly selected artificially stained incisors were obtained. The specimens were divided into three groups of 20 teeth each: Group 1 – 30% hydrogen peroxide, Group II – 20% hydrogen peroxide, and Group III – 10% hydrogen peroxide. One half of the tooth was bleached with hydrogen peroxide, and other was bleached with hydrogen peroxide and pineapple extract for 20 min (Subgroup A) and 10 min (Subgroup B).Statistical Analysis:The results were statistically analyzed using student's t-test.Results:The mean ΔE values of Group IA (31.62 ± 0.9), Group IIA (29.85 ± 1.2), and Group IIIA (28.65 ± 1.2) showed statistically significant higher values when compared to the mean Δ E values of Group 1A (25.02 ± 1.2), Group IIA (22.86 ± 1.1), and Group IIIA (16.56 ± 1.1). Identical results were obtained in Subgroup B.Conclusion:The addition of pineapple extract to hydrogen peroxide resulted in effective bleaching.

Evaluation of the Erosive Potential of Selected Isotonic Drinks: In Vitro Studies.

Isotonic drinks are an important component of the diet of athletes. Sports drinks cause the body to maintain proper hydration and supplement minerals which are lost in sweat during excessive exercising. Aside from the benefits of isotonic drinks, it is important to be aware of the harmful effects of citric acid within the products, which could cause enamel erosion. The aim of the study was to evaluate the erosive potential of sports drinks using confocal scanning laser microscopy (CLSM). The studies measured the change of surface roughness of the dental enamel after etching using Isostar, Powerade and Gatorade drinks, and Fortuna orange juice. Measurements were repeated after 1, 2 and 3 h of exposure to the selected liquid. The evaluation of calcium compound contents was carried out using the complexonometric method. The surface roughness measurements of dental enamel showed that the lowest values of the parameters Ra and Rz were obtained for Isostar and orange juice. The research of the calcium content in the selected beverages showed the highest value in Isostar (320.0 mg/L) and the lowest in Powerade (40.0 mg/L) and Gatorade (21.0 mg/L). Our study confirms that Isostar is the safest sports drink, among the analyzed beverages, for athletes, because it causes the least erosive changes in dental enamel. It is recommended to supplement beverages to reduce their potential for erosion using calcium compounds.

Histochemical changes of occlusal surface enamel of permanent teeth, where dental caries is questionable vs sound enamel surfaces.

This in vitro study was to classify questionable for caries occlusal surfaces (QCOS) of permanent teeth according to ICDAS codes 1, 2, and 3 and to compare them in terms of enamel mineral composition with the areas of sound tissue of the same tooth. Partially impacted human molars (60) extracted for therapeutic reasons with QCOS were used in the study, photographed via a polarised light microscope and classified according to the ICDAS II (into codes 1, 2, or 3). The crowns were embedded in clear self-cured acrylic resin and longitudinally sectioned at the levels of the characterised lesions and studied by SEM/EDX, to assess enamel mineral composition of the QCOS. Univariate and multivariate random effect regressions were used for Ca (wt%), P (wt%), and Ca/P (wt%). The EDX analysis indicated changes in the Ca and P contents that were more prominent in ICDAS-II code 3 lesions compared to codes 1 and 2 lesions. In these lesions, Ca (wt%) and P (wt%) concentrations were significantly decreased (p=0.01) in comparison with sound areas. Ca and P (wt%) contents were significantly lower (p=0.02 and p = 0.01 respectively) for code 3 areas in comparison with codes 1 and 2 areas. Significantly higher (p=0.01) Ca (wt%) and P (wt%) contents were found on sound areas compared to the lesion areas. The enamel of occlusal surfaces of permanent teeth with ICDAS 1, 2, and 3 lesions was found to have different Ca/P compositions, necessitating further investigation on whether these altered surfaces might behave differently on etching preparation before fissure sealant placement, compared to sound surfaces.

Dental Defects as a Potential Indicator of Chronic Malnutrition in a Population of Fallow Deer (Dama dama) from Northwestern Germany

We studied enamel defects in mandibular cheek teeth of fallow deer from an enclosed population that had grown far beyond the carrying capacity of its habitat. Macroscopic inspection revealed a high frequency of pathological enamel alterations in the permanent premolars and the third molar, which form late during dental development, while earlier forming teeth (deciduous premolars and first molar) were generally not affected. Macroscopic enamel alterations comprised opacity and posteruptive discoloration, loss of occlusal enamel ridges, and presence of enamel surface lesions. Backscattered electron imaging in the SEM revealed a marked hypomineralization and related increased porosity of the outer compared to the central and inner enamel portions in the affected teeth. In contrast, the enamel of the unaffected first molars showed a homogeneous high degree of mineralization. Microindentation hardness testing demonstrated a significantly reduced and highly variable hardness of the outer enamel of the affected teeth. The recorded enamel alterations are indicative of a disturbance of enamel maturation. Based on findings of experimental studies by other authors that explored the effects of dietary deficiencies on the mineralization of dental hard tissues in different mammal species, we suggest a dietary calcium deficiency as the cause of the observed pathological enamel changes in the fallow deer. The supposed calcium deficiency only affected teeth whose crown mineralization takes place after weaning, while the deciduous premolars and the first molar, whose crown formation occurs prenatally or during the early postnatal period of intense milk feeding, were unaffected. Anat Rec, 299:1409-1423, 2016. © 2016 Wiley Periodicals, Inc.