Content Of Enamel Research Articles

Knadungan Unsur Fluor pada Email Gigi TetaP Muda dengan Tumpatan Semen Ionomer Kaca Viskositas Tinggi

The purpose of this study was to determine the fluoride content differences in enamel of immature teeth with Glass Ionomer Cement Fuji IX and Ketac Molar filling.The subject for this study was 21 immature premolars teeth, and each tooth divided into 2 parts. The first part filled with Fuji IX (Fuji IX ART, GC) and the second part filled with Ketac Molar (KetacMolar ART, MI, 3M ESPE), so the samples were 21 Energy Dispersive X-Ray Spectrophotometry analysis of Fuji IX and 21 Energy Dispersive X-Ray Spectrophotometry analysis of Ketac molar. The measurement was done to the fluoride content in enamel of immature teeth using Energy Dispersive X-Ray Spectrophotometry in percentage.This study using t-test, exhibited differences but no significant from the percentage of delta the fluoride content in enamel of immature teeth with Fuji IX and Ketac Molar filling (t=1,953 p > 0.05). DOI: 10.14693/jdi.v15i2.74

Elemental content of enamel and dentin after bleaching of teeth (a comparative study between laser-induced breakdown spectroscopy and x-ray photoelectron spectroscopy)

The elemental content of the superficial and inner enamel as well as that of dentin was analyzed using laser-induced breakdown spectroscopy (LIBS) and x-ray photoelectron spectroscopy (XPS) of bleached and unbleached tooth specimens. It is thus clear from the spectral analysis using both the LIBS and XPS technique that elemental changes (though insignificant within the scopes of this study) of variable intensities do occur on the surface of the enamel and extend deeper to reach dentin. The results of the LIBS revealed a slight reduction in the calcium levels in the bleached compared to the control specimens in all the different bleaching groups and in both enamel and dentin. The good correlation found between the LIBS and XPS results demonstrates the possibility of LIBS technique for detection of minor loss in calcium and phosphorus in enamel and dentin.

Characterisation of developmentally hypomineralised human enamel

ObjectivesTo investigate and clarify physical and chemical properties of enamel affected by molar incisor hypomineralisation (MIH). MethodsA series of in vitro studies were performed on extracted molars affected by MIH and sound teeth for controls. Tooth sections underwent Vickers microhardness testing before lapping and subsequent transverse microradiographic analysis and examination under polarised light microscopy. Carbonate content was determined by CO2 release from acid digestion. Unprepared and fractured surfaces were examined under scanning electron microscopy. ResultsMIH-affected molars demonstrated a severe degree of hypomineralisation with an average mineral content of only 58.8%vol% mineral. Vickers microhardness was significantly reduced in MIH compared with controls (1.8±1.1 v 4.4±1.0GPa, p<0.05) and polarised light microscopy revealed the bulk of MIH lesions had a porosity of ≤5% but also substantial areas of ≥10% and smaller areas exceeding 25% porosity. A surface layer was frequently observed on both intact and broken-down lesions and cervical regions of MIH teeth were typically spared. Carbonate content of MIH enamel was higher than control samples (6.6±2.1 v 4.4±1.1wt%, p<0.05). Scanning electron microscopy showed that both the enamel rod and surface ultrastructure were defective. Clinical characteristics did not consistently correlate with all properties. ConclusionsThe properties of MIH-affected enamel significantly differ from those of normal enamel and were highly variable, however some common characteristics were observed. Implications for aetiology and clinical management are discussed.

저농도의 불화나트륨을 함유한 불소제제가 치질의 강도와 화학적 성분에 미치는 영향

본 연구는 시판되는 불소양치용액과 불소치약을 4주간 적용한 다음 법랑질 재광화 효과와 화학적 성분에 미치는 영향을 표면미세경도계와 전자현미분석 (EPMA)를 이용하여 비교분석하였다. 경도측정한 결과, 0.23% 불화나트륨이 함유된 불소치약만 적용한 그룹과 0.02% 불소양치용액과 0.23% 불소치약을 병용한 그룹에서는 3주 후부터 그룹 간의 뚜렷하게 유의한 차이를 보였다 (p<0.05). 전자현미분석을 통한 치아의 주요성분인 Ca, P의 정량적인 성분분석을 시행한 결과, 불화나트륨이 함유된 불소치약만 적용한 그룹과 불소양치용액과 불소치약을 병용한 그룹에서는 유의한 차이를 보였다 (p<0.05). P 수치 변화는 모든 그룹에서 통계적으로 유의한 차이를 보이지 않았다 (p>0.05). 그러므로, 본 연구의 결과 저농도의 불소가 함유되어 있는 불소양치용액과 불소치약을 병용 처리한 경우에 칼슘 수치의 증가와 뚜렷한 표면경도의 증가를 보였음을 확인하였으며, 이는 법랑질의 재광화 효과가 있음을 확인하였다. The purpose of this study was to evaluate the efficacy of gargle and toothpaste containing low concentration with sodium fluoride on the remineralization through the surface microhardness and mineral content in enamel. After 4 weeks-application, the enamel surface was measured using microhardness tester and the calcium (Ca) and phosphorous (P) concentration of mineral content by electron probe microanalyzer (EPMA) analysis. By combining fluoridated gargle with toothpaste, a remineralized enamel resulted in significantly significant differences among the four groups (p<0.05). The Ca change treated with 0.23% fluoridated toothpaste and 0.02% fluoridated gargle with 0.23% toothpaste demonstrated the highest among the other groups. In conclusion. the fluoridated gargle with toothpaste by low concentration showed a significantly greatest synergistic effect on remineralization of the enamel than the other groups.

The Intramembrane Protease SPPL2A Is Critical for Tooth Enamel Formation

Intramembrane proteases are critically involved in signal transduction and membrane protein turnover. Signal-peptide-peptidase-like 2a (SPPL2A), a presenilin-homologue residing in lysosomes/late endosomes, cleaves type II-oriented transmembrane proteins. We recently identified SPPL2A as the enzyme controlling turnover and functions of the invariant chain (CD74) of the major histocompatibility complex II (MHCII) and demonstrated critical importance of this process for B cell development. Surprisingly, we found that SPPL2A is critical for formation of dental enamel. In Sppl2a knockout mice, enamel of the erupted incisors was chalky white and rapidly eroded after eruption. SPPL2A was found to be expressed in enamel epithelium during secretory and maturation stage amelogenesis. Mineral content of enamel in Sppl2a⁻/⁻ incisors was inhomogeneous and reduced by ∼20% compared to wild-type mice with the most pronounced reduction at the mesial side. Frequently, disruption of the enamel layer and localized detachment of the most superficial enamel layer was observed in the knockout incisors leading to an uneven enamel surface. In Sppl2a null mice, morphology and function of secretory stage ameloblasts were not noticeably different from that of wild-type mice. However, maturation stage ameloblasts showed reduced height and a characteristic undulation of the ameloblast layer with localized adherence of the cells to the outer enamel. This was reflected in a delayed and incomplete resorption of the proteinaceous enamel matrix. Thus, we conclude that intramembrane proteolysis by SPPL2A is essential for maintaining cellular homeostasis of ameloblasts. Because modulation of SPPL2A activity appears to be an attractive therapeutic target to deplete B cells and treat autoimmunity, interference with tooth enamel formation should be investigated as a possible adverse effect of pharmacological SPPL2A inhibitors in humans.

The Effect of Storage Solutions on Mineral Content of Enamel

Purpose: This study evaluated the influence of different storage times and storage solutions on the mineral content of enamel. Methods: Ninety enamel slabs were randomly divided into 2 groups of 45: a 45-day group and a 90-day group. Each of these main groups was further subdivided into 9 experimental groups of 5 slabs, and each subgroup was stored in a different storage solution. The mean percentage weights of 5 elements (calcium, potassium, sodium, phosphorus, and magnesium) presented in each enamel slab was measured after storage using inductively coupled plasmaatomic emission spectrometry. Two-way analysis of variance (ANOVA) and Turkey’s honestly significant difference tests were used to analyze differences between the groups. Results: Storage conditions significantly affected the levels of calcium, potassium, sodium, and phosphorus (p 0.05). Storage procedures can significantly affect the calcium, potassium, sodium, and phosphorus contents of enamel.

Estimation of the Enamel and Dentin Mineral Content from the Refractive Index

Recent advances in the field of optics have enabled accurate and localized measurement of optical properties of biological substrates. This work aimed to elucidate the relationship between the local refractive index (n) and mineral content (MC) of enamel and dentin. De- and remineralized lesions in bovine enamel and dentin blocks were sectioned into 300- to 400-µm-thick slices, and placed on a metal plate to capture images of sound, de- and remineralized regions transversely by optical coherence tomography. Mean n at each depth level of the lesion (20- or 40-µm steps for enamel or dentin) was measured by the optical path length-matching method and used to plot n through lesion depth. The specimens were further polished and processed for transverse microradiography for analysis of MC. The n and MC ranged from 1.52 to 1.63 and 50 to 87 (vol.%) in enamel, and from 1.43 to 1.57 and 11 to 48 (vol.%) in dentin, respectively. Strong, positive linear correlations were found between n and MC (Pearson’s r = 0.95 and 0.91 for de- and remineralized enamel, and r = 0.94 and 0.91 for dentin, respectively, p < 0.001). Experimental data were validated with a theoretical calculation of n from MC. De- and remineralization of enamel and dentin resulted in measurable changes of n, and, in turn, MC changes of the tissue could be estimated with good accuracy from this long-known optical property by the new analytical approach. Compositional changes of enamel crystallites after remineralization affect n.

A Comparative Study of Carbonate Determination in Human Teeth Using Raman Spectroscopy

Carbonate determination in dental apatites such as dentine and enamel is important for studying the dynamics of dental caries and developmental defects of these tissues. Traditionally, these determinations have been performed by acidic digestion with the subsequent measurement of released carbon dioxide gas. As an alternative, Raman spectroscopy has been used for the determination of carbonate in synthetic carbonated apatites with at least four analytical methods published thus far. However, these methods have not been applied to biological apatites. The aim of this comparative study was to test the suitability of these four methods for the determination of B-type carbonate in human enamel and dentine. A method for determining the A-type carbonate content of enamel using the Raman technique is also presented. Raman spectra were obtained from 10 human enamel and dentine samples and analysed with each of the four methods using either a single or multiple ν₁(PO₄^3–) band spectral fitting model. Each of the methods resulted in a different determination for the carbonate content when using the same measurement data. The method that used the full-width-at-half-maximum of the ν₁(PO₄^3–) band to determine the B-type carbonate concentration was found to be in best agreement with (i) the results (using the acid digestion method) of teeth collected from the same sample population and (ii) previously reported values for both enamel and dentine. The use of a multiple-band spectral fitting model produced the highest determination precision (particularly in the case of dentine).

Does soy-based infant formula cause ADHD? Update and public policy considerations

An earlier article hypothesized a relationship between soy-based infant formulas, manganese (Mn) neurotoxicity and symptoms of ADHD. In this update, more recent literature on ADHD, Mn and Mn neurotoxicity is reviewed, as well as the risks of Mn toxicity that may accompany ingestion of soy-based infant formula. The results of several critical studies are described, including rodent and primate models that demonstrate an association between ingestion of relatively high levels of Mn and: overactivity, disinhibition and inattention; stereotypes and disturbances of social relatedness; and alterations of dopamine D1 and D2 receptors and dopamine transporter in critical brain regions. Similar deficits have been shown in children with ADHD. In addition, ADHD-like symptoms of behavioral disinhibition were found to be correlated with Mn content in tooth enamel, apparently deposited at or before the fifth gestational month. The results are discussed in terms of their weight as a risk factor in ADHD, vis-à-vis compelling evidence of genetic, epigenetic and other environmental risk factors associated with the disorder, as well as the appropriateness of additional public policy decisions regarding the safety of soy formula.

The Role of Enamel Proteins in Protecting Mature Human Enamel Against Acidic Environments: A Double Layer Force Spectroscopy Study

Characterisation of the electrostatic properties of dental enamel is important for understanding the interfacial processes that occur on a tooth surface and how these relate to the natural ability of our teeth to withstand chemical attack from the acids in many soft drinks. Whereas, the role of the mineral component of the tooth enamel in providing this resistance to acid erosion has been studied extensively, the influence of proteins that are also present within the structure is not well understood. In this paper, we report for the first time the use of double-layer force spectroscopy to directly measure electrostatic forces on as received and hydrazine-treated (deproteinated) enamel surfaces in solutions with different pH to determine how the enamel proteins influence acid erosion surface potential and surface charge of human dental enamel. The deproteination of the treated samples was confirmed by the loss of the amide bands (~1,300–1,700 cm−1) in the FTIR spectrum of the sample. The force characteristics observed were found to agree with the theory of electrical double layer interaction under the assumption of constant potential and allowed the surface charge per unit area to be determined for the two enamel surfaces. The values and, importantly, the sign of these adsorbed surface charges indicates that the protein content of dental enamel contributes significantly to the electrostatic double layer formation near the tooth surface and in doing so can buffer the apatite crystals against acid attack. Moreover, the electrostatic interactions within this layer are a driving factor for the mineral transfer from the tooth surface and the initial salivary pellicle formation.

Demineralization of Enamel in Primary Second Molars Related to Properties of the Enamel

Enamel structure is of importance in demineralization. Differences in porosity in enamel effect the rate of demineralization, seen between permanent and deciduous teeth. Individual differences have been shown in the mean mineral concentration values in enamel, the role of this in demineralization is not thoroughly investigated. The aim of this study was to study variations of depths of artificial lesions of demineralization and to analyze the depth in relation to variations in the chemical and mineral composition of the enamel. A demineralized lesion was created in second primary molars from 18 individuals. Depths of lesions were then related to individual chemical content of the enamel. Enamel responded to demineralization with different lesion depths and this was correlated to the chemical composition. The carbon content in sound enamel was shown to be higher where lesions developed deeper. The lesion was deeper when the degree of porosity of the enamel was higher.

Effect of Music on the Decreased Enamel-Surface Mineral Content of Rat Teeth with Protein Deficiency

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Protein deficiency could lead to enamel hypoplasia and decreased level of Growth Hormone (GH). Cell proliferation and synthesis of enamel-matrix which affect the mineralization process of the tissue, are stimulated by GH. Music was reported to be able to increase GH. Objective: Analyzing the effect of music exposure since prenatal on the decreased Calcium (Ca) and Phosphor (P) content of the enamel-surface of rat-pups in protein-deficiency condition. Experiment: Thirty-two rats on the first day of gestation period were divided into groups with and without music. Music were given twice daily, lullabies every early morning, and classic, baroc, and romantic music every evening. At 2-days-old the rat-pups were further divided into groups with normal diet contained 19.5% protein, and groups with protein deficiency diet contained 7.5% protein. At 2- and 5-weeks-old, 6 rat pups from each group were randomly terminated, the mandibles were dissected out, cut into hemi-mandibles, cleaned, and dried. The percentage of Ca and P content of the lower-incisor enamel-surface was analyzed using Energy Dispersive X-ray (EDX), data were analyzed using One Way ANOVA with a 0.05. Results: At 2-weeks-old, the Ca (8.6%) and P (10.6%) contents of enamel-surface of pups with normal-diet and music were higher than the Ca (3.9%) and P(7.9%) contents of enamel-surface of pups with protein-deficiency with no music (P&lt;0.029). Among 5-weeks-old pups with protein-deficiency, the P content (6.1%) of enamel-surface of pups with music were higher than P content (2.8%) of enamel-surface of pups with no music (P&lt;0.034). Conclusion: Music has a potency to minimize the decreased Ca and P enamel content on the protein deficiency condition.

41Ca in Tooth Enamel. Part I: A Biological Signature of Neutron Exposure in Atomic Bomb Survivors

The detection of (41)Ca atoms in tooth enamel using accelerator mass spectrometry is suggested as a method capable of reconstructing thermal neutron exposures from atomic bomb survivors in Hiroshima and Nagasaki. In general, (41)Ca atoms are produced via thermal neutron capture by stable (40)Ca. Thus any (41)Ca atoms present in the tooth enamel of the survivors would be due to neutron exposure from both natural sources and radiation from the bomb. Tooth samples from five survivors in a control group with negligible neutron exposure were used to investigate the natural (41)Ca content in tooth enamel, and 16 tooth samples from 13 survivors were used to estimate bomb-related neutron exposure. The results showed that the mean (41)Ca/Ca isotope ratio was (0.17 +/- 0.05) x 10(-14) in the control samples and increased to 2 x 10(-14) for survivors who were proximally exposed to the bomb. The (41)Ca/Ca ratios showed an inverse correlation with distance from the hypocenter at the time of the bombing, similar to values that have been derived from theoretical free-in-air thermal-neutron transport calculations. Given that gamma-ray doses were determined earlier for the same tooth samples by means of electron spin resonance (ESR, or electron paramagnetic resonance, EPR), these results can serve to validate neutron exposures that were calculated individually for the survivors but that had to incorporate a number of assumptions (e.g. shielding conditions for the survivors).

Organic and inorganic content of fluorotic rat incisors measured by FTIR spectroscopy

Details on how fluoride interferes in enamel mineralization are still controversial. Therefore, this study aimed at analyzing the organic contents of fluorosis-affected teeth using Fourier Transformation Infrared spectroscopy. To this end, 10 male Wistar rats were divided into two groups: one received 45 ppm fluoride in distilled water for 60 days; the other received distilled water only. Then, the lower incisors were removed and prepared for analysis by two FTIR techniques namely, transmission and micro-ATR. For the first technique, the enamel was powdered, whereas in the second case one fluorotic incisor was cut longitudinally for micro-ATR. Using transmission and powdered samples, FTIR showed a higher C–H content in the fluorotic enamel compared with control enamel ( p < 0.05, n = 4 in the flurotic, and n = 5 in the control group). Results from the micro-ATR-FTIR spectroscopic analysis on one longitudinally cut incisor carried out at six points reveal a higher C–H bond content at the surface of the enamel, with values decreasing toward the dentine–enamel junction, and reaching the lowest values at the subsuperficial enamel. These results agree with the morphological data, which indicate that in the rat incisor the fluorotic lesion is superficial, rather than subsuperficial, as in the case of human enamel. The results also suggest that the increased C–H bond content may extend toward the more basal enamel (intraosseous), indicating that fluorotic enamel may intrinsically contain more protein. Finally, particularly when coupled to ATR, FTIR is a suitable tool to study the rat incisor enamel, which is a largely used model of normal and abnormal amelogenesis. Further studies along this line may definitely answer some questions regarding protein content in fluorotic enamel as well as their origin.

Effect of Galla chinensis on the In Vitro Remineralization of Advanced Enamel Lesions

AimThe effect of Galla chinensis on de-/re-mineralization of advanced enamel lesions was investigated by using micro-CT in a prolonged in vitro experiment.MethodologyBaseline mineral contents of sound enamels were first analyzed. Then lesions were produced in an acidic buffer solution (2.2 mmol·L−1 Ca(NO3)2, 2.2 mmol·L−1 KH2PO4, and pH=4.5) for 21 days, with thrice daily three-minute treatments, divided into four groups: Group A, 4 000 ppm crude aqueous extract of Galla chinensis (GCE); Group B, 4 000 ppm gallic acid; Group C, 1 000 ppm F aq. (as NaF, positive control); Group D, deionized water (negative control). Next, the blocks were immersed in a remineralization solution (1.5 mmol·L−1 CaCl2, 0.9 mmol·L−1 KH2PO4, 0.1 ppm F, and pH=7.0) for 200 days. Mineral loss (ML) in each region of interest(ROI) and integrated mineral loss (IML) of the lesions were calculated (comparing with baseline mineral content of sound enamel) at different time points.ResultsAfter 21 days demineralization, fluoride treatment showed a statistically significant demineralization-inhibiting effect among the four groups, and after 200 days of remineralization, mineral content recovery was ordered (lowest to highest) as A=C<B<D.ConclusionGCE could slow down the remineralization of enamel in the surface layer and thereby facilitate ion transport into the lesion body. The mechanism of Galla chinensis in enhancing the remineralization of dental caries is different from fluoride.

GEP, a Local Growth Factor, is Critical for Odontogenesis and Amelogenesis

Granulin epithelin precursor (GEP) is a new growth factor that functions in brain development, chondrogenesis, tissue regeneration, tumorigenesis, and inflammation. The goal of this study was to study whether GEP was critical for odontogenesis and amelogenesis both in vivo and in vitro. The in situ hybridization and immunohistochemistry data showed that GEP was expressed in both odontoblast and ameloblast cells postnatally. Knockdown of GEP by crossing U6-ploxPneo-GEP and Sox2-Cre transgenic mice led to a reduction of dentin thickness, an increase in predentin thickness, and a reduction in mineral content in enamel. The in vitro application of recombinant GEP up-regulated molecular markers important for odontogenesis (DMP1, DSPP, and ALP) and amelogenesis (ameloblastin, amelogenin and enamelin). In conclusion, both the in vivo and the in vivo data support an important role of GEP in tooth formation during postnatal development.

Ultrastructural Analyses of Deciduous Teeth Affected by Hypocalcified Amelogenesis Imperfecta from a Family with a Novel Y458X FAM83H Nonsense Mutation

Background: Nonsense mutations in FAM83H are a recently described underlying cause of autosomal dominant (AD) hypocalcified amelogenesis imperfecta (AI). Objective: This study aims to report a novel c.1374C>A p.Y458X nonsense mutation and describe the associated ultrastructural phenotype of deciduous teeth. Methods: A family of European origin from the Iberian Peninsula with AD-inherited AI was ascertained. Family members were assessed through clinical examination and supporting investigations. Naturally exfoliated deciduous teeth from 2 siblings were investigated by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and transverse microradiography (TMR). Results: On clinical and radiographic investigation the appearances of the affected deciduous and permanent teeth were consistent with hypocalcified AI with small focal areas of more normal looking enamel. DNA sequencing identified a novel c.1374C>A p.Y458X FAM83H nonsense mutation in affected, but not in either unaffected family members or unrelated controls. Exfoliated teeth were characterised by substantial post-eruptive enamel loss on gross examination. Irregular, poor quality enamel prisms were observed on SEM. These were coated in amorphous material. TMR and EDX confirmed reduced mineral and increased organic content in enamel, respectively. Conclusions:FAM83H nonsense mutations have recently been recognised as a cause of AD hypocalcified AI. We report a novel nonsense FAM83H mutation and describe the associated preliminary ultrastructural phenotype in deciduous teeth. This is characterised by poorly formed enamel rods with inappropriate retention of amorphous material, which is likely to represent retained organic matrix that contributes to the overall hypomineralised phenotype.

Dental enamel irradiated with infrared diode laser and photo-absorbing cream: part 2--EDX study.

The effects of laser-induced compositional changes on the enamel were investigated by energy-dispersive X-ray fluorescence spectrometry (micro-EDX). After cariogenic challenge, we administered treatment of low-level infrared diode laser and a photo-absorbing cream (used to intensify the superficial light absorption). Dental caries is considered the most prevalent oral disease. A simple and noninvasive caries preventive regimen is treating tooth enamel with a laser, either alone or in combination with fluoride, which reduces enamel solubility and dissolution rates. High power lasers are still not widely used in private practice. Low-power near-infrared lasers may be an alternative approach. Energy-dispersive micro-EDX is a versatile and nondestructive spectroscopic technique that allows for a qualitative and quantitative elemental analysis of inorganic enamel components, such as calcium and phosphorus. Twenty-four extracted or exfoliated caries-free deciduous molars were divided into six groups: 1) control group (CTR-no treatment); 2) infrared laser treatment (L) (lambda = 810 nm, 100 mW/cm(2), 90 sec, 4.47 J/cm(2), 9 J); 3) infrared laser irradiation and photo-absorbing agent (CL); 4) photo-absorbing agent alone (C); 5) infrared laser irradiation and fluoridated photo-absorbing agent (FCL); and 6) fluoridated photo-absorbing agent alone (FC). Samples were analyzed using micro-EDX after two sets of treatments and pH cycling cariogenic challenges. The CL group showed statistically significant increases in calcium and phosphorus (wt%) compared with the CTR group. The Ca/P ratio was similar in the FCL and CTR groups. There was a significant laser-induced reduction compared with the CTR group, and there was a possible modification of the organic balance content in enamel treated with laser and cream. micro-EDX may be able to detect compositional changes in mineral phases of lased enamel under cariogenic challenge. Our results suggest that with a combined laser and photo-absorbing agent (CL) treatment, there was a possible disorganization of organic content in the tooth enamel with hydroxyapatite crystal reordering and reorganization.

Physical and Compositional Changes on Demineralized Primary Enamel Induced by CO2 Laser

This in vitro study aimed to evaluate the physical and chemical changes promoted by a CO(2) laser at 10.6-microm wavelength on primary dental enamel with artificial caries-like lesions. Several previous investigations have shown that enamel can be modified by CO(2) laser to obtain a caries-preventive effect, but the specific mechanism remains uncertain. Twenty-seven primary molars were randomly assigned to three groups as follows: control, carious, and laser (n = 9). The specimens from the carious and laser groups were demineralized and treated with or without CO(2) laser, according to the group. Enamel surface changes after treatments were monitored using Fourier transform Raman spectroscopy and scanning electron microscopy (SEM). The Raman spectra showed a statistically significant reduction of mineral content in carious and laser groups when compared to control group. Additionally, carbonate content was reduced in irradiated specimens when compared to the other groups. No physical change was observed in specimens evaluated by SEM. The results suggest that CO(2) laser irradiation may reduce the carbonate content of enamel, which is likely to make this substrate more acid-resistant.

Dental enamel irradiated with infrared diode laser and photoabsorbing cream: Part 1 -- FT-Raman Study.

The aim of this FT-Raman study was to investigate laser-induced compositional changes in enamel after therapy with a low-level infrared diode laser and a photoabsorbing cream, in order to intensify the superficial light absorption before and after cariogenic challenge. Dental caries remains the most prevalent disease during childhood and adolescence. Preventive modalities include the use of fluoride, reduction of dietary cariogenic refined carbohydrates, plaque removal and oral hygiene techniques, and antimicrobial prescriptions. A relatively simple and noninvasive caries preventive regimen is treating tooth enamel with laser irradiation, either alone or in combination with topical fluoride treatment, resulting in reduced enamel solubility and dissolution rates. Due to their high cost, high-powered lasers are still not widely employed in private practice in developing countries. Thus, low-power red and near-infrared lasers appear to be an appealing alternative. Twenty-four extracted or exfoliated caries-free deciduous molars were divided into six groups: control group (no treatment; n = 8); infrared laser treatment (L; n = 8) (810 nm at 100 mW/cm(2) for 90 sec); infrared diode laser irradiation (810 nm at 100 mW/cm(2) for 90 sec) and photoabsorbing cream (IVL; n = 8); photoabsorbing cream alone (IV; n = 8); infrared diode laser irradiation (810 nm at 100 mW/cm(2) for 90 sec) and fluorinated photoabsorbing agent (IVLF; n = 8); and fluorinated photoabsorbing agent alone (IVF; n = 8). Samples were analyzed using FT-Raman spectroscopy before and after pH cycling cariogenic challenge. There was a significant laser-induced reduction and possible modification of the organic matrix content in enamel treated with the low-level diode laser (the L, IVL, and IVFL groups). The FT-Raman technique may be suitable for detecting compositional and structural changes occurring in mineral phases and organic phases of lased enamel under cariogenic challenge.