Enamel Surface Changes Research Articles

Er: YAG Laser Assisted Bleaching Procedures Effect on Enamel Topography

The aim of this study was to evaluate the effect of using Er: YAG laser during in-office tooth bleaching on enamel surface. Method: Thirty enamel discs specimens of human anterior teeth and divided into three groups, Group 1: (control) specimens received no bleaching treatment; Group 2: specimens received conventional in-office bleaching treatment using Opalescence Boost PF tooth whitening systems; Group 3: specimens received laser assisted bleaching procedure using low energy Er: YAG laser to assist tested bleaching gels. After bleaching, Specimens were stored for 15 days in artificial saliva. Digital microscope and images analysis used to evaluate surface roughness. Scanning electron micrographs were captured to evaluate enamel surface changes. Data were statistically analyzed using Aasistat 7.6 statistics software with Student t-test. Results Conventional in-office bleached enamel showed statistically significant higher enamel surface roughness than unbleached enamel surface with changes in enamel surface morphology were observed. While ER: YAG laser assisted bleached enamel, surfaces showed non-statistically significant higher enamel surface roughness than unbleached enamel surface with minor changes in enamel surface morphology were observed. Conclusions: Tested laser assisted bleaching procedures showed safely enamel surface treatment than conventional in-office bleaching procedures.

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.

CHEMICAL AND MORPHOLOGICAL ANALYSIS OF HUMAN DEMINERALIZED ENAMEL SURFACE BY ACID AND LASER ETCHING FOLLOWING REMINERALIZATION BY MI PASTE PLUS

Objectives: The aim of the present study was to evaluate the effects of remineralizing agent (MI Paste Plus) on the surface topography and chemical analysis of sound human enamel following acid-etching and laser etching, using Environmental scanning electron microscopic (ESEM) techniques.Materials and Methods: Fifty human upper premolars extracted for orthodontic reason were used. The teeth were mounted vertically in a self-cure acrylic cylinder. One clinician prepared all the teeth, in each tooth; a 4x4 mm area was treated in middle third of the buccal surface. The teeth were divided into three groups, Group I : Control group no treatment ; Group II: enamel etched with 37% phosphoric acid; Group III: enamel was irradiated with Er,Cr:YSGG laser. Group II and III were subdivided into subgroup according to remineralizing agent (GC MI Paste Plus), (n=10). Remineralizing paste was used as manufacturer’s instructions, a single application of approximately 0.5 mm layer for 3 minutes; twice daily. Synthetic saliva was rinsing between remineralizing paste application, followed by synthetic saliva rinsing for 15 days with fresh replenished on a daily basis. Teeth were examined for morphological and chemical characterization using an Environmental Scanning Electron Microscope. All of the data were analyzed by two-way analysis of variance (ANOVA) and Tukey’s post hoc test. Results: Morphological changes of enamel surfaces of acid-etching group showed type 1 etching pattern and laser etching group showed the normal appearance of the enamel prisms (honeycomb-like structure). Comparison of all groups and control group P & Ca weight%, the greatest mean value was recorded in acid etch group before and after remineralization with GC MI Paste Plus. Conclusion: Within the limits of this in vitro study, Since Ca and P constitute the major part of tooth structure, while other element represent trace element; results emphasize the effect of GC MI Paste Plus on tooth remineralization. Comparison of all groups and control group, acid etch group before and after remineralization recorded the greatest mean value for P & Ca weight%. Laser etching didn’t have a significant effect on tooth composition and mineral content.

Effect of 10% Strontium Chloride and 5% Potassium Nitrate with Fluoride on Bleached Bovine Enamel.

Background:Dental whitening has been increasingly sought out to improve dental aesthetics, but may cause chemical and morphological changes in dental enamel surfaces.Objective:This study evaluated in vitro the effect of 10% strontium chloride and 5% potassium nitrate with fluoride on bovine enamel, through tristimulus colorimetry, Knoop microhardness (KHN), and roughness after bleaching with 35% hydrogen peroxide (HP).Methods:The specimens were divided into three groups (n=15): GControl received bleaching treatment with 35% HP; GNitrate received bleaching with 35% HP followed by the application of 5% potassium nitrate with 2% sodium fluoride; and GStrontium received bleaching with 35% HP followed by the application of 10% strontium chloride on the enamel. Next, five specimens of each experimental group were subjected to KHN and tristimulus colorimetry tests, and 10 specimens were subjected to surface roughness (SR) tests. The values obtained for the different groups were compared through analysis of variance (ANOVA) followed by a post-hoc Tukey-Kramer test in addition to Student’s T-test for paired data.Results:In the intergroup comparison, KHN final differed statistically (p<0.05). The mean SR final of the experimental groups differed statistically from the GControl group (p<0.05). In addition, the groups did not differ in color variation (p>0.05).Conclusion:10% strontium chloride and 5% potassium nitrate combined with 2% fluoride downplayed morphological changes to the enamel, without interfering with the effectiveness of the bleaching process.

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.

Chemical Composition and Microhardness of Human Enamel Treated with Fluoridated Whintening Agents. A Study in Situ.

Background:Dental whitening has been increasingly sought out to improve dental aesthetics, but may cause chemical and morphological changes in dental enamel surfaces.Objective:Assess in situ the effects of high-concentration hydrogen peroxide with and without fluoride on human dental enamel using the ion chromatography test (IC) and the Knoop hardness test (KHN).Material and Methods:Nineteen enamel specimens were prepared using third human molars. These specimens were fixed on molars of volunteers and were divided into groups: OP38-Opalescence Boost PF38%, PO37-Pola Office 37.5% and CO-Control group. For chemical analysis (n= 3), the dentin layer was removed, keeping only the enamel, which was subjected to acidic digestion by microwave radiation. It was necessary to perform sample dilutions for the elements fluorine (F), calcium (Ca) and phosphorus (P) for quantification using the IC test. The KHN (n= 5) was performed before and after the treatments. Five indentations were made, separated by 100 µm, for each specimen using a load of 25 gf for 5 seconds in the microdurometer. The data were analyzed using ANOVA with a 5% significance level.Results:The OP38 group had the largest concentrations of F, Ca and P ions. The PO37 group showed the lowest concentrations of F and Ca ions. The average KHN was not significantly different between the OP38 and PO37 groups.Conclusion:Enamel whitened with hydrogen peroxide containing fluoride had greater concentrations of F, Ca and P ions. The presence of fluoride in the whitening agent did not influence the enamel microhardness.

The effects of fractional CO2 laser, Nano-hydroxyapatite and MI paste on mechanical properties of bovine enamel after bleaching.

BackgroundThis study investigated the effect of post bleaching treatments to the change of enamel elastic modulus and microhardness after dental bleaching in- vitro.Material and MethodsFifty bovine incisor slab were randomly assigned into five groups (n=10). The samples were bleached for three times; 20 minutes each time, by 40% hydrogen peroxide. Next it was applied fractional CO2 laser for two minutes, Nano- hydroxy apatite (N-HA) and MI-paste for 7 days and 2 minutes per day. The sound enamel and bleached teeth without post treatment remained as control groups. The elastic modulus and microhardness were measured at three times; 24 hours, 1 and 2 months. Data were statistically analyzed by two-way analysis of variance with 95% confidence level.ResultsDifferent methods of enamel treatment caused a significant increase in elastic modulus compared to bleached group (P<0.05). Modulus was significantly increased in 1 and 2 months (P<0/001: bleach, P= 0/015: laser, P= 0/008: NHA, P=0/010: MI paste) but there were no significantly difference between 1 and 2 months (P>0.05). There was any significance difference for hardness among treated and control groups, but hardness increased significantly by increasing storage time (P<0.05).ConclusionsThe use of the protective tested agents can be useful in clinical practice to reduce negative changes of enamel surface after whitening procedures. Key words:Bleaching enamel, CO2 laser, MI pastes, Nano-hydroxy apatite, Microhardness, Elastic modulus.

In vitro study to evaluate laser fluorescence device for monitoring the effect of aluminum gallium arsenide laser on noncavitated enamel lesions

Objective: The objective of this study was to evaluate the efficacy of laser fluorescence (LF)-based diagnostic device for monitoring the effect of aluminum gallium arsenide (Al Ga As) laser on noncavitated enamel lesions. Background: Dental caries is a reversible disease, and scope of reversing the carious lesion is increased if it is diagnosed before there is surface cavitation. Variegated remineralization strategies including remineralizing pastes and different lasers have been explored. The efficacy of this surface treatment requires a valid and a reliable assessment tool. LF is one such adjunct to traditional methods of caries detection. Materials and Methods: Twenty-five intact freshly extracted molars were sectioned mesiodistally so as to obtain fifty samples which were coated with nail varnish so that 3 mm × 3 mm of windows are created to maintain uniformity. All sample surfaces were evaluated with LF device so as to obtain the baseline values, these values served as control. All the samples were then acid etched by 30% phosphoric acid for 20 s to simulate surface demineralization. The LF device was used to record the values of demineralized samples. The surfaces of the teeth were then irradiated with Al Ga As laser of 3.5 W for 30 s. The LF device was then used to record the reading. Statistical Analysis Used: Statistical analysis was done using paired t-test to compare control and test groups and calculation of the mean. Results: The demineralized surfaces have recorded statistically significant LF values greater than the untreated control sample values. Post laser irradiation, there is fall of the LF values and these values are closer to that of control. Conclusion: Laser fluorescence can be used as a tool to detect demineralization in situ and monitor changes in enamel surface during demineralization and remineralization phases. Surface treatment with laser irradiation gave values closer to that of control and this does indicate that laser irradiation brings about surface alteration as evaluated by laser fluorescence.

ESEM ANALYSIS OF ENAMEL SURFACE MORPHOLOGY ETCHED WITH ER,CR:YSGG LASER AND PHOSPHORIC ACID: IN VITRO STUDY

Objectives: The aim of the present study was to evaluate the etching pattern of Er,Cr:YSGG and conventional etching on prepared samples of human enamel by environmental scanning electron microscope (ESEM). Materials and Methods: Forty five freshly extracted human upper premolars were used; the teeth had been extracted for orthodontic reasons and were collected and stored in a solution of 0.1% (wt/vol) thymol. The teeth were mounted vertically in a self-cure acrylic cylinder. One clinician prepared all the teeth, in each tooth, a 4x4 mm area was treated in middle third of the buccal surface. The teeth were divided into three groups according to type of etching techniques (n=15).Group(A): enamel etched with 37% phosphoric acid for 30 s, thoroughly rinsed with distilled water for 60 s and gently air dried.; Group (B): enamel was irradiated with Er,Cr:YSGG laser ablated with an energy output of 4.5 watt/30hz and Group (C):enamel was irradiated with Er,Cr:YSGG laser ablated with an energy output of 4.5 watt/20hz. In group b & c Er,Cr:YSGG laser (2.78 μm wavelength) used for 15 sec at 45degree angulations working distance 5mm on a square size 4x4mm on buccal surface. Micro-morphological changes of enamel surface were evaluated using an environmental scanning electron microscope at X250 & X1500 magnification. Results: In this study, laser with 30 Hz reveals a definite change in the surface of the enamel, most of the enamel prisms are interrupted showing an irregular outline. However laser with 20 Hz showed the ultra-structural appearance of enamel nearly similar to that of conventionally etched enamel with 37 percent phosphoric acid. Conclusion: Within the limits of this in vitro study, both conventional acid etching & laser 20 Hz etching showed nearly similar effect on enamel surface, so the laser-etching can be successfully used as an alternative to the conventional acid-etch. On the other hand laser 30 Hz etching failed to induce an effect on enamel surface comparable to that of acid etching and therefore can’t be used as substitute for the conventional acid –etch.

SEM Evaluation of Enamel Surface Changes and Enamel Microhardness around Orthodontic Brackets after Application of CO2 Laser, Er,Cr:YSGG Laser and Fluoride Varnish: An In vivo Study.

One of the most undesirable consequences of orthodontic treatment is occurrence of enamel demineralization around orthodontic brackets. Numerous in vitro studies have reported the prevention of enamel demineralization by surface treatment with lasers and fluoride varnish. To evaluate the changes on the enamel surface and microhardness around orthodontic brackets after surface treatment by CO2 laser, Er, Cr:YSGG laser and fluoride varnish in vivo. A double blind interventional study was carried out on 100 premolars which were equally divided into five groups, out of which one was the control group (Group 0). The intervention groups (Group I to IV) comprised of patients requiring fixed orthodontic treatment with all 4 first premolars extraction. Brackets were bonded on all 80 premolars which were to be extracted. Enamel surface treatment of Groups I, II and III was done by CO2 laser, Er, Cr:YSGG laser and 5% sodium fluoride varnish respectively and Group IV did not receive any surface treatment. A modified T-loop was ligated to the bracket and after two months, the premolars were extracted. Surface changes were evaluated by Scanning Electron Microscopic (SEM) and microhardness testing. Comparison of mean microhardness between all the groups was assessed using post-hoc test with Bonferroni correction. Group I showed a melted enamel appearance with fine cracks and fissures while Group II showed a glossy, homogenous enamel surface with well coalesced enamel rods. Group III showed slight areas of erosions and Group IV presented areas of stripped enamel. Significant difference was observed between the mean microhardness (VHN) of Group I, Group II, Group III, Group IV and Group 0 with p<0.001. A significant difference of p<0.001 was observed while comparing Group I vs II,III,IV,0 and Group II vs III,IV,0. However, difference while comparing Group III vs IV was p=0.005 and difference between the mean microhardness of Group 0 vs Group III was non significant. Surface treatment with Er,Cr:YSGG laser causes a positive alteration of the enamel surface increasing its ability to resist demineralization with optimum microhardness as compared to CO2 laser and sodium fluoride varnish.

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.

Characterization and Preparation of Calcium Phosphate Model Toothpaste for Tooth Enamel Remineralization

Calcium phosphates are excellent biomaterial for hard tissue regeneration and replacement. Recently, nanohydroxylapatite (HAp) has been intensively studied as remineralization agent for tooth enamel protection and remineralization. In this research, we developed model toothpaste composition, determined viscosity and investigated weather different processed – spray-dried (spCDHAp), lyophilized (lyoCDHAp), wet precipitated (paste-like consistence, pCDHAp) – calcium deficient hydroxyapatite (CDHAp) affect bovine tooth enamel remineralization. Model toothpastes components were CDHAp, 2-hydroxyethylcelluloce, glycerol and water. Viscosity varied from 2.5 to 40 Pa∙s. Model toothpastes with 20 wt% CDHAp showed thixotropic behaviour, thereby we examined them as potential tooth remineralization pastes. After in vitro remineralization enamel surface changes were detected, the texture of demineralized surface and bundles of HAp crystals were not observed. It was suggested, that new calcium phosphate layer was formed on the enamel. In conclusion, CDHAp is very promising material for enamel regeneration, but different pretreatment of CDHAp (resulting as different morphology of agglomerates) did not give distinctive remineralization results.

Prenatally administered HMB modifies the enamel surface roughness in spiny mice offspring: An atomic force microscopy study

ObjectiveThe aim of this research was to check the effect of the prenatally administered β-hydroxy β-methylbutyrate (HMB) on the development of enamel surface of the spiny mice offspring. DesignThe spiny mice dams were randomly assigned into three groups: control group (not supplemented with HMB) and two experimental groups in which powdered HMB was given at the daily dosage of 0.2g/kg of body weight (group I) and 0.02g/kg of body weight (group II) during the last period of gestation. Newborn pups were euthanized by CO2 inhalation. The morphology of incisor teeth was analysed using atomic force microscopy (AFM) in semi-contact mode in the height, magnitude and phase domains. Height images became a basis for determination of surface roughness parameters. ResultsConducted study indicated that maternal HMB administration markedly influences enamel development. Enamel of offspring’s teeth in both experimental groups was characterized by significantly smaller values of indices describing surface roughness and profile. HMB supplementation influenced the calculated parameters regardless of the diet type and offspring sex, however higher dose of HMB caused stronger changes in enamel surface’s physical properties and could be observed in higher intensity in the male group. ConclusionsHMB administration caused reduction in the irregularities of enamel surface, thereby possibly reducing the probability of bacteria adhesion and caries development. These observations may serve to improve nutrition and supplementation of animals and could be a lead for further research.

Effect of Single and Two Step Application of Antioxidant Incorporated Bleaching Agents on Bond Strength of Resin Composite and Surface Changes in Enamel

Objective: The aim of this in vitro study was to incorporate two antioxidants namely sweet potato and grape seed extracts with 30% hydrogen peroxide and to evaluate its effect on the enamel surface and the bond strength of resin composite to enamel. Materials and Methods: Labial enamel surfaces of 90 extracted human maxillary central incisors were randomly divided into 6 groups of 15 each based on different bleaching protocols. Groups I and II were allotted to negative (no bleaching) and positive (bleaching with 30% hydrogen peroxide only) controls. The rest were the experimental groups; bleaching with 30% hydrogen peroxide incorporated with 2% sweet potato and 5% grape seed extracts (Groups III and IV respectively) and bleaching followed by application of sweet potato and grape seed extracts (Groups V and VI respectively). Following bleaching procedure, 5 specimens were evaluated for surface changes under SEM and the remaining 10 specimens were immediately restored with resin composite and were subjected to shear bond strength evaluation under universal testing machine. Results: Significantly higher shear bond strength values were observed in teeth treated with the experimental bleaching solution containing 2% sweet potato extract (Group III) as compared to the other groups. Comparatively lesser morphological changes in enamel were also observed under SEM for Group III. 5% grape seed extract showed better results when used as a separate step rather than when incorporated in the bleaching agent. Conclusion: Addition of 2% sweet potato extract in bleaching agent reduces deleterious effects on enamel, enhances bonding of resin composites to bleached enamel significantly and does not require additional clinical steps.

Differential diagnosis of dental fluorosis made by undergraduate dental students.

ABSTRACTObjective To check knowledge of undergraduate dental students to make diagnosis of dental fluorosis with varying degrees of severity and choose its appropriate treatment.Methods Data were collected using a semi-structured questionnaire addressing knowledge of undergraduates based on ten images of mouths presenting enamel changes.Results Only three images were correctly diagnosed by most undergraduates; the major difficulty was in establishing dental fluorosis severity degree.Conclusion Despite much information about fluorosis conveyed during the Dentistry training, as defined in the course syllabus, a significant part of the students was not able to differentiate it from other lesions; they did not demonstrate expertise as to defining severity of fluorosis and indications for treatment, and could not make the correct diagnosis of enamel surface changes.

Enamel Surface Changes After Exposure to Bleaching Gels Containing Carbamide Peroxide or Hydrogen Peroxide.

This study evaluated the differences in enamel color change, surface hardness, elastic modulus, and surface roughness between treatments with four bleaching gels containing carbamide peroxide (two at 10% and one each at 35%, and 45%) and two bleaching gels containing hydrogen peroxide (two at 40%). Enamel specimens were bleached and color changes were measured. Color change was calculated using either ΔE or the Bleaching Index (BI). Then, surface hardness, elastic modulus, and surface roughness of the enamel specimens were evaluated. All measurements were performed at baseline and directly after the first bleaching treatment for all carbamide peroxide- and hydrogen peroxide-containing bleaching gels. In addition, final measurements were made 24 hours after each of a total of 10 bleaching treatments for carbamide peroxide bleaching gels, and 1 week after each of a total of three bleaching treatments for hydrogen peroxide bleaching gels. After the last bleaching treatment, respective ΔE scores were 17.6 and 8.2 for the two 10% carbamide peroxide gels, 12.9 and 5.6 for the 45% and 35% carbamide peroxide gels, and 9.6 and 13.9 for the two 40% hydrogen peroxide gels. The respective BI scores were -2.0 and -2.0 for the two 10% carbamide peroxide gels, -3.5 and -1.5 for the 45% and 35% carbamide peroxide gels, and -2.0 and -3.0 for the two 40% hydrogen peroxide gels. Each bleaching gel treatment resulted in significant whitening; however, no significant difference was found among the gels after the last bleaching. Whitening occurred within the first bleaching treatments and did not increase significantly during the remaining treatments. Surface hardness significantly decreased after the last bleaching treatment, when 10% carbamide peroxide was used. Furthermore, significant changes in the elastic modulus or surface roughness occurred only after treatment with 10% carbamide peroxide. All six bleaching gels effectively bleached the enamel specimens independent of their concentration of peroxide. Gels with low peroxide concentration and longer contact time negatively affected the enamel surface.

Effects of Bleaching Agents Combined with Regular and Whitening Toothpastes on Surface Roughness and Mineral Content of Enamel.

The purpose of this study was to evaluate surface roughness and changes in the composition of enamel submitted to different bleaching protocols and toothbrushing with regular and whitening toothpastes. Bleaching treatment could promote morphological and chemical changes in enamel surface. Enamel blocks were randomized into nine groups (n=10) according to the bleaching treatment (no bleaching, control group; 6% hydrogen peroxide, HP; or 10% carbamide peroxide, CP) and toothpaste used (placebo, PL; regular, R; or whitening dentifrice, W). Bleaching was performed according to manufacturers' instructions and all groups were submitted to 30,000 cycles of simulated toothbrushing with toothpaste (PL, R, or W). Mineral content evaluation and enamel roughness were evaluated initially (T1), after bleaching (T2), and after toothbrushing (T3), using an energy-dispersive micro X-ray fluorescence spectrometer and profilometry, respectively. Data were statistically analyzed with two way ANOVA, Tukey, and Dunnett tests (5%). Enamel surface roughness was influenced by bleaching and toothbrushing. Surface roughness increased for the groups that brushed with the placebo dentifrice (CP+PL, HP+PL, C+PL) and for the control group that brushed with whitening dentifrice (C+W). Enamel Ca/P ratio decreased after bleaching, but toothbrushing, regardless of the dentifrice used, did not reduce the enamel mineral content. The bleaching treatment resulted in a decrease of enamel mineral content, but the studied dentifrices did not contribute to surface mineral loss.

Clinical enamel surface changes following an intra-oral acidic challenge

ObjectivesInvestigation of early enamel erosion using replica impressions to compare changes in enamel surface topography in vivo prior to and over a 24h period following acid challenge. MethodA single treatment, blinded, enamel replica clinical study was undertaken in 20 healthy subjects. Replica tooth impressions were taken at baseline, following acid challenge and 2, 4, 7 and 24h post challenge. Subjects consumed 500ml of acidic soft drink over 30min. Scanning electron microscopy of surface tomography was characterised with a descriptive 5 point scale by four judges. Duplicate impressions were taken to assess reproducibility. Results18 subjects had scorable sequences. Descriptive analyses showed erosive changes following acid consumption and reparative changes in the subsequent 24h period. Comparing baseline replica to the 24h replica, there were no significant differences (p=0.26) in tooth surface characteristics. Comparing the replica taken immediately following acidic challenge with the subsequent replicas at 2, 4, 7 and 24h, showed clear reduction of erosive effects on the enamel surface at 2h (p=0.02) and a highly significant reduction at 4, 7 and 24h (p<0.001). ConclusionThis methodology demonstrated the ability to follow the progression and recovery of early erosive enamel lesions over 24h being accurate and reproducible. This study suggests enamel repair commences within 2h following a substantial acidic challenge and is completed 4–24h later. After 24h, the tooth surface appeared visibly indistinguishable from the original tooth surface, suggestive of a recovery process occurring. Clinical significanceHealthy erosive lifestyles often culminate in tooth wear. The time taken for enamel remineralisation following acidic challenge is unknown however, this study suggests the repair process is relatively slow following a substantial acidic challenge, and at least 4–24h should elapse prior to further acidic consumption to allow for recovery.

Erosive Potential of Medicated Syrups on Primary Teeth: An In vitro Comparative Study

Aims: This in vitro study was designed to investigate the exogenous erosive potential of most commonly used pediatric syrup medicaments on primary teeth. Place and Duration of Study: Department of Pediatric Dentistry, Vishnu Dental College, Bhimavaram, India, 2012 to 2013. Methodology: The erosive potential of 17 syrups was assessed by measuring their inherent pH, titratable acidity, viscosity and ability to erode enamel. The inherent pH and titratable acidity of syrups were measured using digital pH meter and viscosity was determined using Brookfield viscometer. Enamel surface changes were evaluated using optical 3D profilometer. Original Research Article Kiran et al.; BJMMR, 5(4): 525-532, 2015; Article no.BJMMR.2015.057 526 Results: Api –up (appetizer) showed the least pH and Azee (Azithromycin) exhibited the highest pH. The titratable acidity was greater for Api-up (5.40ml) and least for Tonoferron (0.20ml). Asthalin exhibited highest viscosity and Ondem showed least viscosity. All the test syrups caused some degree of enamel loss, however, Api – up caused the greatest and Azee caused the least degree of enamel loss at three time intervals. Conclusion: The medicated syrups with low inherent pH and high viscosity showed to cause a greater dissolution of enamel. However, certain syrups with low viscosity had shown higher degree of enamel loss due to their inherent acidic pH and those with high viscosity Showed lesser degree of enamel loss due to their basic pH. Hence, these results proved that inherent pH is the most critical factor for erosion.

Enamel surface changes caused by hydrogen sulfide.

Background:Volatile sulfur compounds (VSCs) produced inside the mouth are a well-known cause of halitosis. Recent studies have suggested that VSCs modify the pathology of periodontitis by encouraging the migration of bacterial toxins associated with increased permeability of gingival epithelia, and enhancing the production of matrix metalloproteinases in gingival connective tissue. Nonetheless, the effects on the enamel of direct exposure to VSCs within the oral cavity remain unclear.In the present study, we observed the effects of VSCs in the form of hydrogen sulfide (H2S) on enamel surfaces and determined their effects on restorations.Materials and Methods:Extracted human tooth and bovine tooth samples were divided into the H2S experimental side and the control side. We observed the effects of H2S on enamel surfaces using electron microscopy and conducted a shear test.Results:We found that exposure to H2S obscured the enamel surface's crystal structure. The surface also exhibited coarseness and reticular changes. Shear testing did not reveal any differences in bond strength.Conclusions:Our findings suggested that H2S occurring inside the mouth causes changes to the crystal structure of the enamel surface that can lead to tooth wear, but that it does not diminish the effects of dental bonding in adhesive restorations.