Enamel Of Permanent Teeth Research Articles

Lead contents in the surface enamel of primary and permanent teeth, whole blood, serum, and saliva of 6- to 8-year-old children

This study aimed to evaluate associations of Pb-enamel values determined in two successive enamel microbiopsies taken from a primary and a permanent tooth, and to assess how Pb-enamel correlates with Pb-blood and Pb-serum as well as whole (Pb-whole-saliva), submandibular/sublingual (Pb-sub-saliva) and parotid saliva (Pb-parotid-saliva). The study population included 444 children aged 6 to 8 years attending 4 government schools in the district of Campos Eliseos, in Ribeirao Preto, Sao Paulo State, Brazil. Whole blood, serum, parotid, submandibular/sublingual (“sub-saliva”), and whole saliva were collected in trace element-free tubes. Two successive microbiopsies were taken from the surface of a primary and a permanent tooth of each child. Lead concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS). There was a significant correlation between primary and permanent teeth in terms of Pb-enamel, for both the first and the second microbiopsies. When the median Pb-enamel values were compared between the two genders using only the highest 10th percentile Pb-enamel, there was a significant difference between girls and boys for both primary (474.2 vs 910.0 μg/g, respectively; p = 0.02) and permanent teeth (739.5 vs 1325 μg/g, respectively; p = 0.04). There were no significant correlations between Pb-enamel and Pb-blood or between Pb-enamel and lead in the 3 different salivas. However, there was a statistically significant correlation between Pb-enamel and Pb-serum when only the highest 10th percentile Pb-enamel was analyzed (r = 0.57 and p = 0.0002 for primary teeth; r = 0.56 and p < 0.0001, for permanent teeth). In conclusion, our findings have demonstrated a significant correlation between Pb-enamel found in primary and permanent teeth, as well as a significant correlation between Pb-serum and lead in primary and permanent tooth enamel. Boys presented higher Pb-enamel than girls. Our study also suggests that Pb-enamel has no correlation with Pb-blood or with lead in the 3 different salivas.

Childhood lead exposure and uptake in teeth in the Cleveland area during the era of leaded gasoline

Childhood uptake of lead from exposure to atmospheric leaded gasoline in the United States has been studied using mainly blood lead levels. Since reliable blood lead techniques were used only after the peak use of leaded gasoline, the prior exposure history is unclear. The well-documented decline in blood lead levels after the mid-1970s could represent the continuation of a historic steady decline in exposure from many sources. Alternatively, the post-1970s decline might represent the declining phase of a unimodal rise and fall corresponding closely to usage of leaded gasoline. To assess these possibilities, lead concentration and 207Pb/206Pb isotope ratios were measured in the enamel of permanent molar teeth formed between 1936 and 1993 in mainly African-American donors who grew up in the Cleveland area. Tooth enamel preserves the lead concentration and isotope ratio that prevails during tooth formation. Historical trends in enamel lead concentration were significantly correlated with surrogates of atmospheric lead exposure: lead in sediments of two dated Lake Erie cores, and lead consumed in gasoline. About two-thirds of the total lead uptake into enamel in this period was attributable to leaded gasoline, and the remainder to other sources (e.g. paint). Enamel 207Pb/206Pb isotope ratios were similar to those of one lake sediment. Multivariate analysis revealed significant correlation in neighborhoods with higher levels of traffic, and including lake sediment data, accounted for 53% of the variation in enamel lead levels. Enamel lead concentration was highly correlated with reported African-American childhood blood levels. The extrapolated peak level of 48 μg/dL (range 40 to 63) is associated with clinical and behavioral impairments, which may have implications for adults who were children during the peak gasoline lead exposure. In sum, leaded gasoline emission was the predominant source of lead exposure of African-American Cleveland children during the latter two-thirds of the 20th century.

Chemical, mechanical and morphological properties of hypomineralized enamel of permanent first molars

Objective. The microstructure of hypomineralized enamel in permanent teeth has been described in several studies as less distinct prism sheaths and disorganized enamel with lack of organization of the enamel crystals. The mechanical properties, hardness and modulus of elasticity of the hypomineralized enamel have lower values compared with normal. The aim of this study was to examine normal and hypomineralized enamel using scanning electron microscopy (SEM), hardness measurements and X-ray microanalysis (XRMA). Material and methods. Four extracted hypomineralized permanent first molars, sectioned and cut in half, were analyzed with SEM, XRMA and hardness measurements. Results. An inverse relation was found between the micro hardness and the Ca:C ratio in hypomineralized and normal enamel. The acid-etched hypomineralized enamel appeared on SEM to be covered with a structureless layer and the prisms appeared disorganized, with thick prism sheaths and loosely packed crystallites. Furthermore, bacteria were found deep in porous hypomineralized enamel close to the enamel–dentin junction. Conclusions. Teeth diagnosed with molar incisor hypomineralization have significantly lower hardness values in the hypomineralized enamel compared with normal enamel. The hardness values vary according to the morphological and chemical properties.

Microstructure and mineral composition of dental enamel of permanent and deciduous teeth

This study evaluated and compared in vitro the microstructure and mineral composition of permanent and deciduous teeth's dental enamel. Sound third molars (n = 12) and second primary molars (n = 12) were selected and randomly assigned to the following groups, according to the analysis method performed (n = 4): Scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Energy dispersive X-ray spectrometer (EDS). Qualitative and quantitative comparisons of the dental enamel were done. The microscopic findings were analyzed statistically by a nonparametric test (Kruskal-Wallis). The measurements of the prisms number and thickness were done in SEM photomicrographs. The relative amounts of calcium (Ca) and phosphorus (P) were determined by EDS investigation. Chemical phases present in both types of teeth were observed by the XRD analysis. The mean thickness measurements observed in the deciduous teeth enamel was 1.14 mm and in the permanent teeth enamel was 2.58 mm. The mean rod head diameter in deciduous teeth was statistically similar to that of permanent teeth enamel, and a slightly decrease from the outer enamel surface to the region next to the enamel-dentine junction was assessed. The numerical density of enamel rods was higher in the deciduous teeth, mainly near EDJ, that showed statistically significant difference. The percentage of Ca and P was higher in the permanent teeth enamel. The primary enamel structure showed a lower level of Ca and P, thinner thickness and higher numerical density of rods.

Scanning electron microscopy evaluation of the bonding mechanism of a self-etching primer on enamel.

The aim of this study was to analyze the effect of a self-etching primer (Transbond Plus SEP, 3M Unitek, Monrovia, Calif), developed for orthodontic use, in the regularity and depth of adhesive infiltration in the enamel of human permanent teeth and to compare it with phosphoric acid using scanning electron microscopy (SEM). Thirty premolars were divided in two groups of 15 each: group 1(control)-phosphoric acid + Transbond XT Primer (3M Unitek) and group 2- Transbond Plus SEP. Transbond XT Adhesive Paste (3M Unitek) was used in both groups for bracket bonding. All products were used according to the manufacturer's instructions. Dental fragments were decalcified, and for micromorphologic observation of the adhesive penetration in enamel, the resin replicas, remnant at the base of the brackets, were covered with a thin gold layer and examined by SEM. Three calibrated examiners evaluated the photomicrographs and gave scores from 0 = without penetration to 2 = deep penetration. The Mann Whitney U-test (P < .0001) showed a statistical difference between the two groups. The results demonstrated that the SEP was more conservative and produced a smaller amount of demineralization and less penetration of adhesive in the enamel surfaces when compared with the conventional phosphoric acid system.

Remineralization of initial carious lesions in deciduous enamel after application of dentifrices of different fluoride concentrations

The aim of the present study was to evaluate the remineralization potential of five dentifrices with different fluoride concentrations. Initial caries lesions were created in 72 cylindrical enamel blocks from deciduous teeth. The specimens were randomly distributed among six experimental groups corresponding to six experimental periods. Each of the six volunteers carried two deciduous enamel specimens fixed in an intraoral appliance for a period of 4 weeks. They brushed their teeth and the enamel blocks at least two times a day with dentifrices containing 0 ppm (period 1), 250 ppm (period 2), and 500 ppm fluoride (period 3), respectively. A second group of volunteers (n = 6) used dentifrices with a fluoride content of 0 ppm (period 4), 1,000 ppm (period 5), or 1,500 ppm (period 6). At the end of the respective period, the mineral content was determined by transversal microradiography (TMR). The use of dentifrices containing 500 ppm fluoride (38% MR), 1,000 ppm fluoride (42% MR), and 1,500 ppm fluoride (42% MR) resulted in a statistically significant higher mineral recovery compared to the control group (0 ppm fluoride). Mineral recovery was similar after use of dentifrices containing 0 and 250 ppm fluoride (24%; 25%). It is concluded that it is possible to remineralize initial carious lesions in deciduous enamel in a similar way as it has been described for enamel of permanent teeth.

Clinical and microstructural aberrations of enamel of deciduous and permanent teeth in patients with autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy

Objective Autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy (APECED) causes multiple endocrine deficiencies, oral candidiasis and different forms of ectodermal dystrophy including enamel hypoplasia, documented in permanent teeth. Our purpose was to examine dental aberrations associated with APECED, including possible manifestations in primary teeth. Design We studied clinically, radiographically, and by scanning electron microscopy (SEM) teeth of children belonging to two APECED families with different mutations in the AIRE gene. Results In addition to enamel defects in the permanent teeth we observed hypoplastic pits and hypomaturated patches in the deciduous teeth with underlying changes in the prismatic ultrastructure. The enamel of the permanent molars exhibited a layered arrangement with included whirl-like formations. Conclusions Our findings confirm that APECED causes enamel defects that are individually but chronologically distributed, and can alter enamel development early enough to affect deciduous teeth.

Kandungan Unsur Fluorida pada Email Gigi Tetap Muda yang Di Tumpat Semen Ionomer Kaca dan Kompomer

The purpose of this study was to determine the fluoride uptake in enamel of young permanent teeth between Glass Ionomer Cement and Compomer filling. The subject for this study was 21 premolar, and each tooth divided into 2 parts. The first part filled with Glass Ionomer Cement (Fuji IX ART,GC), and the second part filled with Compomer (Dyract, Denstsply), so the samples were 21 Energy Dispersive X-Ray Spectrophotometry analysis of Glass Ionomer Cement and 21 Energy Dispersive XRay Spectrophotometry analysis of Compomer. Using t-test the fluoride uptake in the enamel of young permanent teeth with Glass Ionomer Cement and Compomer filling was significantly increased(t=3,705 p=0.001). The increasing of fluoride uptake in the enamel of young permanent teeth with Glass Ionomer Cement filling is more high than Compomer. This study also showed fluoride uptake from Glass Ionomer Cement and Compomer which exhibited in enamel of young permanent teeth was significantly different (t=3,705 p=0.001). Fluoride uptake of Glass Ionomer Cement filling in enamel of immature teeth was much more compare to Compomer. DOI: 10.14693/jdi.v15i3.28

Pengaruh Durasi Aplikasi Asam Fosfat 37% terhadap Kekuatan Geser Restorasi Resin Komposit pada Email Gigi Tetap

Phosphoric acid etching has been widely used to achieve a strong and long lasting mechanical bonding between composite resin restoration and tooth structure. The aim of this study was to evaluate the bond strength between the enamel of permanent teeth and the composite resin restoration by measuring the shear bond strength after different durations of etching. In total 27 premolar teeth were divided into 3 groups where the enamel of the buccal surface was etched with 37% phosphoric acid for 5″, 15″, and 25″ before placing the composite resin restoration. After keeping the teeth inside an incubator for 24 hours, the shear bond strength was measured using a universal testing machine Shimazu AG-5000 at a crosshead speed of 0.5 mm/min. ANOVA was used for statistical analysis of the results, with p 0.05). Conclusion: Shear bond strength of the composite resin on the permanent teeth enamel increased with increasing etching time. Significant difference was showed between 5″ and 25″ of etching time. DOI: 10.14693/jdi.v15i2.65

A clinical and histological study of dental defects in a 10‐year‐old girl with pseudoxanthoma elasticum and amelogenesis imperfecta

The prominent dental feature of a 10-year-old girl was severely hypoplastic enamel in permanent teeth. Severe dental defects were detected in a 10-year-old female patient affected by pseudoxanthoma elasticum and amelogenesis imperfecta. An orthopantomographic examination revealed a reduction of enamel thickness on the crown of all erupted and unerupted teeth, agenesis of the maxillary right second premolar, delayed eruption of mandibular first premolars, and the presence of large calcifications in all tooth pulp chambers. A detailed histological analysis of permanent mandibular first molars showed that pulp calcifications presented a concentric laminate organization and merged to almost completely obliterate the pulp chamber. Osteodentine was visible all along the pulpal surface of the radicular dentine. Broad resorption areas were present in the outermost dentine at both coronal and radicular levels. Radicular resorption areas presented a typical rectangular form and were filled with acellular cementum. Cementum thickness was highly increased on the root surface. Apposition of cellular cementum-like tissue was also observed on the coronal dentine surface. Before treating patients affected by amelogenesis imperfecta and/or pseudoxanthoma elasticum, paediatric dentists should be aware of the presence of pulp calcifications that add to the complexity of endodontic procedures.

Estimation of trace elements in sound and carious enamel of primary and permanent teeth by atomic absorption spectrophotometry: An in vitro study

The influence of trace elements on the prevalence of caries is a complex subject. However, the demonstration of an inverse relationship between caries prevalence and fluoride (F) intake indicates the potential effect of trace elements on caries. This in vitro study sought to estimate and compare the trace element concentrations in sound and carious enamel of primary and permanent teeth. Forty sound and carious primary and permanent teeth, extracted from children and adolescents of Davangere city, were collected. The teeth were divided into four groups (of ten each) and enamel samples were prepared by mechanical grinding. The trace elements were estimated using atomic absorption spectrophotometer. The results of our study showed the presence of 18 trace elements (F, Sr, K, Al, Si, Ni, B, Fe, Cu, Mn, Co, Cr, Zn, Mg, Se, Pb, Mo, and V) in the enamel of sound and carious primary and permanent teeth. The mean, standard deviation, and range (at 95% confidence level) were calculated for each element. The concentrations of F, Sr, and K were significantly ( P <0.05) higher in sound enamel of permanent teeth than in sound enamel of primary teeth. The concentrations of F, Sr, K, Al, and Fe were significantly ( P <0.05) higher in sound enamel of permanent teeth than in carious enamel of permanent teeth. The concentrations of F, K, and Si were significantly ( P <0.05) higher in sound enamel of primary teeth than in carious enamel of primary teeth.

Quantitative analysis of the calcium and phosphorus content of developing and permanent human teeth

It was the aim of this study to investigate the distribution of Ca, P and C in predentin, dentin and enamel in human tooth buds and permanent teeth by EDX element analysis. The mandible of a 16-week-old human fetus containing eight mineralizing tooth buds and three human permanent molars were fixed in formaldehyde and embedded in Technovit 9100. Serial sections of 80 microm thickness of the mandible were cut in the frontal-dorsal direction, and polarized light micrographs were taken of these sections. The permanent teeth were cut in mesio-distal direction. The sections were investigated with scanning electron microscopy and EDX element analysis with a Philips XL 30 FEG scanning microscope and an EDAX energy-dispersive X-ray system using spot measurements, EDX line-scans and element mapping. Quantitative measurements were made in predentin, mineralizing dentin adjacent to predentin, mature dentin, mineralizing enamel and young enamel of developing teeth and mature enamel of permanent teeth. In developing teeth the Ca and P content increased rapidly from outer predentin towards mineralizing dentin. In enamel prisms of developing teeth the Ca and P content increased linearly from the surface towards the enamel-dentin junction. In permanent teeth only a small layer of predentin was found. The Ca and P content in enamel and circumpulpal dentin of permanent teeth was higher than in developing teeth. The Ca/P ratio differed between predentin and dentin areas reflecting different calcium phosphate compositions, but it was the same in mineralizing and young enamel. The differences in the distribution of Ca and P reflect different mineralizing patterns of the enamel and dentin matrices.

Qualitative and quantitative evaluation of enamel after various stripping methods

In this study, we investigated ultramorphology, surface roughness, and microhardness of permanent and deciduous tooth enamel after various stripping methods. One hundred twenty deciduous and permanent teeth (n = 60 each) were used. Qualitative (scanning electron microscopy) and quantitative (surface roughness and microhardness tests) experiments were carried out in the following experimental groups: group 1, stripping disk; group 2, diamond-coated metal strip; group 3, stripping disk and Sof-Lex discs (3M-ESPE, Seefeld, Germany); group 4, diamond-coated metal strip and Sof-Lex discs; group 5 (chemical stripping), 37% orthophosphoric acid in conjunction with diamond-coated metal strip; group 6 (control), no stripping. Surface roughness values (Ra) for permanent and deciduous enamel were evaluated with Welch analysis of variance (ANOVA) and Tamhane tests, and Kruskal-Wallis and Mann-Whitney tests, respectively. Microhardness values were evaluated statistically with Kruskal-Wallis, 1-way ANOVA, and Duncan tests. Deciduous and permanent teeth showed similar results in terms of surface roughness and surface morphology. Groups 3 and 4 had the smoothest deciduous and permanent enamel surfaces, whereas chemical stripping (group 5) produced the roughest surfaces in both enamel types. Stripping did not lead to a significant change in the microhardness of permanent enamel. All stripping methods significantly roughened the enamel surfaces. Polishing the stripped surface with Sof-Lex discs decreased the roughness.

Comparative ablation rate from a Er: YAG laser on enamel and dentin of primary and permanent teeth

This study was conducted to analyze the ablation rate and micromorphological aspects of microcavities in enamel and dentin of primary and permanent teeth using a Er: YAG laser system. Micromorphological evaluation has been performed in terms of permanent teeth; however, little information about Er: YAG laser interaction with primary teeth can be found in the literature. Because children have been the most beneficiary patients with laser therapy in our offices, it is extremely necessary to compare the effects of this kind of laser system on the enamel and dentin of permanent and primary teeth. In this study, we used eleven intact primary anterior exfoliated teeth and six extracted permanent molar teeth. We used a commercial laser system: a Er: YAG Twin Light laser system (Fotona Medical Lasers, Slovenia) at 2940 nm, changing average energy levels per pulse (100, 200, 300, and 400 mJ) producing 48 microcavities in enamel and dentin of primary and permanent teeth. Primary teeth are more easily ablated than are permanent teeth, when related to enamel or dentin. However, while this laser system is capable of slowly revealing the enamel’s microstructure, in dentin only the lowest laser energies permit this kind of observation, more easily decomposing the original tissue aspect, when related to primary or permanent teeth. Statistically, the only different factor at the 5% level was an energy per pulse of 400 mJ, confirming the results found in SEM. Our results showed that dentin in both primary and permanent teeth is less resistant to Er: YAG laser ablation; this fact is easily observed under SEM observation and through the ablation rate evaluation.

Hardness of enamel exposed to Coca‐Cola® and artificial saliva

The purpose of this study was to determine the rate of change in indentation hardness of enamel in permanent teeth exposed to Coca-Cola. In a further experiment, the ability of a commercially available artificial saliva to remineralize enamel treated with Coca-Cola was tested. Ten enamel specimens were randomly chosen to be treated with Coca-Cola (experimental groups) and seven with water (control group). The fluids were applied for 1, 2, 3 h and overnight (15 h), washed off with a few drops of water and the moist enamel indentation hardness tested after each interval. With Coca-Cola treatment, the mean enamel hardness was 92.6% (s.d. = 7.9) of the original baseline hardness after 1 h, 93.25% (s.d. = 10.15) after 2 h, 85.7% (s.d. = 12.03) after 3 h and 80.3% after 15 h. The mean indentation hardness of control specimens treated with water was 108.7% (s.d. = 16.09) of the original hardness after 1 h, 99.09% (s.d. = 18.98) after 2 h, 98.97% (s.d. =11.24) after 3 h and 98.42% (s.d. = 22.78) after 15 h. In a separate experiment, the hardness of 9 enamel specimens was tested, as previously described, before and after treatment with Coca-Cola overnight and again after application of artificial saliva for 3 min. Coca-Cola reduced the mean indentation hardness of enamel in the teeth, but the hardness was partially restored with artificial saliva (Salivart) and increased by 18% from the demineralized enamel hardness.

A comparative evaluation of four restorative materials to support undermined occlusal enamel of permanent teeth

The purpose of this study was to test the support to undermined occlusal enamel provided by posterior restorative composite (FiltekTM P60, 3M Dental products USA), polyacid modified resin composite (F2000 compomer, 3M Dental products, USA.), radiopaque silver alloy-glass ionomer cement (Miracle Mix. GC Corp, Tokyo, Japan) and Glass Ionomer cement (Fuji IX GP). To test each material, 20 human permanent mandibular third molars were selected. The lingual cusps were removed and the dentin supporting the facial cusps was cut away, leaving a shell of enamel. Each group of prepared teeth was restored using the materials according to the manufacturer's instructions. All the specimens were thermocycled (250 cycles, 6 degrees C- 60 degrees C, dwell time 30 seconds) and then mounted on an acrylic base. Specimens were loaded evenly across the cusp tips at a crosshead speed of 5 mm /minute in Hounsfield universal testing machine until fracture occurred. Data obtained was analyzed using analysis of variance and Studentized- Newman- Keul's range test. No significant differences were detected in the support provided by P-60, F 2000, Miracle Mix or Fuji IX GP groups. The support provided to undermined occlusal enamel by these materials was intermediate between no support and that provided by sound dentin. Without further development in dental material technology and evidence of its efficacy, restorative materials should not be relied upon to support undermined occlusal enamel to a level comparable to that provided by sound dentin.

In vitro occlusal wear of restorative materials on primary teeth

Since primary tooth enamel wears more rapidly than permanent tooth enamel, it is important to study the mechanical wear patterns of restorative materials used in the primary dentition. It is important that an in vitro evaluation of wear resistance of different restorative materials is done in order to establish a valid in vitro test protocol for use in pediatric dentistry.

Does Caries in Primary Teeth Predict Enamel Defects in Permanent Teeth? A Longitudinal Study

The notion that caries in primary teeth causes developmental defects of enamel in permanent teeth has been recently revived. The research objective was to test this hypothesis through analysis of data from the Dunedin Multidisciplinary Health and Development Study, a longstanding prospective cohort study. The maxillary incisors of 663 children were assessed for existing restorations and dental caries at age five and for developmental defects of enamel at age nine. Where a primary tooth had been carious, the permanent successor was more likely to have a demarcated opacity after adjustment for gender, family socio-economic status, years of exposure to water fluoridation, trauma to primary teeth, and early loss of primary teeth (unadjusted OR = 2.3, 95% CI 1.3, 4.1; adjusted OR = 2.2, 95% CI 1.1, 4.3). These findings support a time-ordered association between dental caries in primary maxillary incisors and demarcated opacities in their permanent successors.

Mechanical properties across hypomineralized/hypoplastic enamel of first permanent molar teeth

The aims of the present study were to investigate the mechanical properties of first permanent molars affected with enamel hypomineralization or hypoplasia, and to describe the appearance of these lesions under scanning electron microscopy. Eight first permanent molar test teeth and two unaffected premolars (controls) were enclosed in resin, then sectioned axially and polished. The hardness and modulus of elasticity was determined from a single array of indentations made parallel to the amelo-dentinal junction using an Ultra-Micro-Indentation system. The teeth were then examined using the scanning electron microscope. The mechanical properties of the test teeth in the unaffected cervical region (hardness and modulus range, 2.03-4.99 GPa and 50.39-96.87 GPa, respectively) were similar to those of the control enamel (hardness and modulus range, 2.71-4.15 GPa and 62.06-95.77 GPa, respectively). Between the unaffected cervical enamel and the hypomineralized region there was a transitional area of 500-600 microm where the mechanical properties in the experimental teeth decreased linearly. The mechanical properties of the hypomineralized region of each experimental tooth were significantly lower than those of the control or cervical regions (hardness and modulus range, 0.07-1.74 GPa and 3.26-40.96 GPa, respectively). The scanning electron microscopy views revealed disorganized enamel with poorly demarcated prism boundaries in the affected regions. In conclusion, the hardness and modulus of elasticity of hypomineralized enamel in first permanent molars is significantly less than in unaffected areas of the same tooth. The reason for this is unclear but may be related to the lack of organization of the enamel crystals.

A resource guide for practice development through technology

A resource guide for practice development through technology