Enamel Surface Microhardness Research Articles

The Abrasive and Remineralising Efficacy of Coturnix Eggshell

The objective of this research was to determine the abrasive and remineralising efficacy of quail eggshell (Coturnix coturnix) incorporated into a new experimental toothpaste. An experimental study was designed to compare the surface microhardness of the dental enamel of bovine lateral incisors exposed to different toothpastes. In relation to microroughness (abrasive efficiency), the unit of analysis was each specimen with 16 polymethylmethacrylate (PMMA) blocks. For the remineralisation variable, the unit of analysis was each bovine lateral incisor tooth. A sample size of 16 was determined for each group. The unpolished PMMA specimens presented the highest mean surface microroughness with a mean of 4.60 ± 1.47 µm, whilst the quail paste, universal polishing paste, control paste, and Diamond Excel Paste showed a mean of 1.16 ± 0.40 µm, 0.63 ± 024 µm, 0.45 ± 0.22 µm, and 0.43 ± 0.17 µm, respectively, presenting significant differences (P < .001). When comparing the surface microhardness of bovine lateral incisor dental enamel exposed to different toothpastes, the universal polishing paste presented the lowest microhardness, with 192.43 ± 56.21 kg/mm2, whilst the quail paste presented the greatest remineralising effect, with the highest average of 272 ± 21.18 kg/mm2, followed by the control paste with 244 ± 41.43 kg/mm2 and the Diamond Excel Paste with 228.72 ± 43.72 kg/mm2. These differences were statistically significant (P < .001). Significant differences were found in the surface abrasive efficiency (microroughness) of PMMA subjected to different toothpastes. The quail toothpaste presented statistically significant results compared to the control pastes, the Diamond Excel Paste, and the universal polishing paste.

Effects of black tea tooth staining previously to 35% hydrogen peroxide bleaching

Aim: To determine if the artificial staining with black tea (BT) influences the enamel microhardness before in-office bleaching and if BT staining is necessary to evaluate the efficacy of bleaching with 35% hydrogen peroxide Methods: Enamel/dentin blocks were randomized into groups according to the staining protocol (n=5/group): (CO) control – maintained in artificial saliva solution (AS); (BT4) immersed in black tea solution for 4 h; (BT24) immersed in black tea solution for 24 h. After the staining protocols, all specimens were kept in AS for one week, followed by bleaching (three sessions of HP application for 40 min). Knoop surface microhardness (kgF/mm2) was determined at baseline (T0), after staining (T1), after 7 days of storage in AS (T2), and after bleaching (T3). The color (ΔE00) and coordinate changes (ΔL, Δa, Δb) were measured using a digital spectrophotometer at T0 and T3. Data were submitted to one-way (ΔE00, ΔL, Δa, Δb) or two-way ANOVA repeated measures (kgF/mm2) and Tukey’s test (a=5%). Results: The staining protocols (BT4 and BT24) promoted significantly lower microhardness (T1 and T2, p&lt;0.05) than CO, whereas CO was the only group to maintain microhardness values over time. Bleaching promoted perceptible ΔE00 without a significant difference among the groups regardless of the staining protocol (p=0.122). CO and BT4 showed no differences in terms of ΔL and Δa (p&gt;0.05), but BT4 displayed a higher Δb than CO. Conclusion: The artificial staining with BT negatively affected the enamel surface microhardness and was not essential to evaluate the efficacy of 35% hydrogen peroxide bleaching.

Effect of Three Treatment Modalities for White Spot Enamel Lesions on Enamel Surface Roughness and Micro-Hardness

Effect of Three Treatment Modalities for White Spot Enamel Lesions on Enamel Surface Roughness and Micro-Hardness

Effect of conventional and power office bleaching with diode laser and led light on enamel microhardness

Aim: The present study aimed to asses enamel microhardness after office bleaching with diode laser and LED light compared to the conventional bleaching procedure. Methods: Thirty-nine human premolar teeth were collected and randomly divided into three groups regarding of the bleaching technique. Group 1: Snow O bleaching gel with LED light-curing unit; Group 2: Snow L bleaching gel with diode laser irradiation; and Group 3: Opalescence Boost bleaching gel with no light source in group 3. Enamel surface changes were evaluated in one tooth in each study group and one intact tooth as a reference under a scanning electron microscope (SEM). In the remaining samples (n=12), enamel microhardness was determined by Vickers microhardness test before and after bleaching. Data were analyzed with repeated-measures ANOVA to compare microhardness changes, followed by post hoc Tukey tests at the 0.05 significance level. Results: Enamel microhardness decreased in all the groups after bleaching, with the maximum decrease in microhardness in the Snow O bleaching group with LED light, which was significantly higher than the other groups (P=0.002). The two other groups did not exhibit any significant difference in microhardness decrease (P&gt;0.05). Conclusion: Based on the limitations of this study, it can be concluded power bleaching with 980nm diode laser was less time-consuming compare to conventional bleaching procedure and yielded better outcomes in terms of enamel surface microhardness compared to the use of an LED light-curing unit.

Impact of Fluoride Varnishes on Enamel Surface Microhardness of Primary Teeth: An In Vitro Study

Impact of Fluoride Varnishes on Enamel Surface Microhardness of Primary Teeth: An In Vitro Study

Effect of Over-The-Counter Tooth-Whitening Products on Enamel Surface Roughness and Microhardness

Background: To evaluate the efficacy of new over-the-counter tooth-whitening products on enamel surface roughness and microhardness. Methods: A total of 120 enamel specimens were prepared and randomly allocated into six groups. Group A was treated with 10% carbamide peroxide; Group B was immersed in distilled water; Group C was treated with hydrated silica, sodium hexametaphosphate toothpaste; Group D was treated with sodium bicarbonate; Group E was treated with 0.25% citric acid; and Group F was treated with hydrated silica, charcoal powder. Results: A, B, and D demonstrated decreased Ra, whereas Groups C, E, and F showed an increased Ra after whitening. The changes in Ra from T0 to T1 in each group was statistically significant (p &lt; 0.001) except for Group B (p = 0.85). The groups showed decreased KHN after whitening, except for specimens in Group B (distilled water). The KHN from T0 to T1 decreased significantly for groups A, C, E, and F (p = 0.001). Significant difference was observed at T1 (p &lt; 0.0001). Conclusion: Within the limitations of this study, it could be demonstrated that surface roughness and enamel microhardness changes were influenced by the type, composition, and exposure time of the whitening product.

Comparative evaluation of Elsenz and GC tooth mousse in remineralization of enamel – a clinical study

Aim: To evaluate the surface micro hardness of enamel following use of ElsenzTM and GC tooth mousse. Methods: Twenty extracted anterior teeth were included for the study. Teeth were decoronated and mounted mesiodistally. Baseline values of the samples were recorded and teeth were randomly divided into 2 groups. Group A: ElsenzTM; Group B: GC tooth mousse. Samples were demineralized with Mc Innes solution (2 cycles, 5 minutes daily with 24-hour gap each) following which remineralization was done for 2 weeks (2 cycles, 5 minutes daily with 7 days gap) and the samples were subjected to micro hardness testing using Vickers hardness tester. The results obtained were subjected to statistical analysis using one way ANOVA and paired t test. Results: GC tooth mousse and ElsenzTM both showed remineralization of enamel, although when statistically compared, there was no significant difference in the micro hardness values in both the groups. Conclusion: Periodic application of ElsenzTM increases micro hardness of enamel and it can be effectively used as remineralizing agent.

Violet led dental whitening: Effectiveness and biological safety: An in vitro study

IntroductionThe light-emitting diode (Led) in the violet spectrum associated or not with hydrogen peroxide (HP) has been suggested as a promising technique for dental bleaching. Violet led has a wavelength of 405–410 nm, which is very close to that of ultraviolet (UV) radiation, and this has raised biological safety concerns. AimTo investigate the effectiveness of the violet led dental bleaching technique by evaluating color parameters, enamel surface microhardness, and biological safety analysis. MethodsOne hundred bovine dental blocks were divided into groups according to the bleaching technique (G1 – only HP; G2 - HP associated with blue led; G3 – only blue led; G4 - HP associated with a violet led; and G5 – only violet led). The color analysis (ΔE, ΔL, and WID) and enamel surface microhardness were assessed before and after bleaching (immediately, 5, 14, and 30 days). The biological safety of the violet led irradiation was assessed by measuring the number of micronuclei formed in human cells in culture in response to irradiation. Data analysis included Kruskal-Wallis test, Friedman test, and Mann-Whitney test. ResultsIn groups G4 and G5 there was the formation of precipitates on the enamel surface. At the time of 14 days, it was observed that the G2 group had lower values of microhardness than G5. ΔL and ΔE showed differences between groups in experimental times. Mean percentages of micronuclei occurrence were similar in the control group and the violet led group. ConclusionThe violet led irradiation can be applied for dental bleaching because this approach produces significant color changes preserving tooth enamel integrity and causes no genotoxic effects on vital cells.

Effect of the nano-fluorapatite ceramic particles on mechanical behavior of fluoride varnishes

Fluoride varnishes or gels have been advised by dentists for any tooth decay. Fluoride varnishes can be assessed based on various factors such as surface micro-hardness. The present study is aimed to evaluate the micro-hardness of enamel surfaces after the application of different types of fluoride varnishes. Three different fluoride varnish compositions were provided which contained different nano-fluorapatite with average particle size of 50 nm, sodium fluoride, Xanthan gum, and Xylitol. For experimental evaluation, twenty primary teeth were collected from subjects aged 3–14. The teeth were washed, cut, and then soaked in the fluoride varnishes for 1 min and then soaked in artificial saliva for 24 h. The nano-fluorapatite and sodium fluoride contents of the studied fluoride varnishes varied from 0.66 to 2.96 wt% and 1.66 to ∼5 wt%, respectively. The results were compared with a commercial fluoride varnish available in the market (Aria Dent Preventa) and two control groups of primary teeth before (Ctrl. group) and after demineralization (D-Ctrl. group). Control and varnish-treated samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectrometry, and field emission electron microscopy (FESEM). Finally, the surface micro-hardness of all specimens was analyzed to determine the enamel surface hardness before and after treatment. Statistical significance between mean values was determined by a one-way analysis of variance. The highest micro-hardness value was 623 HV obtained for the samples with 0.74 wt% nano-fluorapatite content. This value was also higher than untreated tooth sample (532 HV). Moreover, the replacement of solvent by Xanthan gum presents some other advantages such as biocompatibility and biodegradability of Xanthan gum composition. The MTT test showed that the prepared samples exhibited no toxic effect on fibroblast cells after 48 h.

Comparison of the Microhardness of Surface Enamel Exposed to Anti-asthmatic Inhalants

To determine the effect of anti-asthmatic inhalers salbutamol and budesonide on the surface microhardness of bovine tooth enamel. The study was experimental, prospective, longitudinal, and comparative. The sample consisted of permanent mandibular incisors, which were prepared in (n = 90) blocks of dental enamel of size 3 × 3 mm and 2 mm thick, separated into 6 groups of 15 specimens each in sterile bottles properly labeled and contained in artificial saliva at 37°C. Three measurements (baseline, 5 days, and 10 days) were performed after immersion to determine the microhardness using a Vickers microdurometer programmed to apply a load of 100 gm for 15 seconds. It was observed that the enamel surface microhardness decreased after 5 and 10 days, after being in contact with the anti-asthmatic inhalers based on salbutamol and budesonide. In addition, it was evidenced that there is a greater decrease in the superficial microhardness of the enamel when comparing the values at the beginning and after 10 days; likewise, the reduction in the microhardness of enamel exposed to budesonide was greater (120.8 kg/mm2) compared to salbutamol (112.3 kg/mm2) (p<0.001). The two anti-asthmatic inhalers studied decreased superficial enamel microhardness, with the budesonide-based inhaler having a greater erosive effect. This research allowed us to know the values of the microhardness of the superficial enamel after being exposed to different anti-asthmatic inhalers that are indicated in daily clinical practice. Therefore, it is important to evaluate this microhardness since the use of different inhalers is very prevalent.

Effect of penetrating resin on the surface structure, microhardness and color of enamel after bleaching

Objective: To investigate the effect of permeable resin on the surface structure, microhardness and color of tooth enamel after bleaching. Methods: Premolars extracted for orthodontic needs were selected (provided by the Department of Oral and Maxillofacial surgery of the first affiliated Hospital of Zhengzhou University) and randomly divided into A, B and C 3 groups. Each group was randomly divided into control subgroup, resin subgroup, bleaching subgroup and combined subgroup. Samples in the control subgroup did not receive any treatment. Those in the bleaching subgroup and combined subgroup were treated with cold light whitening. Those in the resin group and combined group were treated with permeable resin. Samples in the group A were observed by scanning electron microscope immediately after treatment and 2 weeks after treatment, and the microhardness of samples in the group B was measured before treatment, immediately after treatment and 2 weeks after treatment (the sample size of each time point was 8 in each subgroup). In group C, chromaticity was measured and chromatic aberration (ΔE value) was calculated before treatment, immediately after treatment and 1 and 2 weeks after treatment (10 samples in each subgroup). Results: Scanning electron microscope showed that the enamel surface of the resin subgroup and the combined group was smooth immediately after treatment, which was basically the same as that of the control subgroup, but covered with resin, and microporous defects and mineral deposits could be seen on the surface of the bleaching subgroup. Two weeks after treatment, the enamel surface of each subgroup was smooth, there was no obvious difference. Immediately after treatment, the microhardness of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were (354±33), (364±21), (411±30) and (350±17) HV, respectively (F=9.39,P<0.05). The microhardness of the bleaching subgroup was significantly higher than that of the other subgroups (P<0.05). There was no significant difference in microhardness among the four subgroups before treatment and 2 weeks after treatment (F=0.34, 2.75, P>0.05). Immediately after treatment, the ΔE values of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were 0.00±0.00, 2.29±1.86, 7.20±1.94 and 8.00±0.88, respectively (F=74.21,P<0.05); except that there was no significant difference between bleaching subgroup and combined subgroup (P>0.05), there were significant differences among the other subgroups (P<0.05). There was no significant difference in ΔE value among control subgroup, resin subgroup and bleaching subgroup at each time point (F=1.66, 0.30, 0.96, P>0.05). The difference in the combined subgroup immediately after treatment was significantly higher than that at 1 and 2 weeks after treatment (t=4.73, 4.23,P<0.05), but there was no significant difference between 1 and 2 weeks after treatment (t=0.75, P>0.05), and the color tended to be stable. Conclusions: When whitening healthy enamel, simple cold light whitening or cold light whitening combined with permeation resin can achieve whitening effect.

Effect of Diode Laser and Remineralizing Agents on Microstructure and Surface Microhardness of Therapeutic Gamma-Irradiated Primary Teeth Enamel

BACKGROUND: Radiation caries is a serious complication to head and neck cancer (HNC) radiotherapy, for which the primary teeth are more susceptible to be affected. Preventive protocols are recommended to enhance dental structure resistance against the direct effects of radiotherapy. AIM: The aim of the study is to evaluate the effect of diode laser and two types of remineralizing agents on the microhardness of the primary teeth enamel and examine microstructural alterations. METHODS: Twenty primary molars were sectioned into two halves in a mesiodistal direction, to obtain 40 specimens, which were then randomly allocated into five groups. Group 1 (Control Negative) n = 5 was not subjected to any treatment or radiation. Group 2 (Control positive) n = 5 was gamma irradiated with a dose of 60 Gray. For Groups 3, 4, and 5, specimens were divided into two subgroups: A and B (n = 5/subgroup). Subgroups A were gamma irradiated, then exposed to different surface treatments: 3A:10% nano-hydroxyapatite (nHA) paste, 4A: 5% sodium fluoride varnish (FV), and 5A: diode laser 980 nm. Subgroups B were exposed to surface treatments (3B: 10% nHA, 4 B: 5% FV, and 5B: diode laser 980 nm), then gamma irradiated. Surface micromorphology and microhardness were examined using environmental scanning electron microscope (ESEM), and Vickers microhardness tester, respectively. RESULTS: Group 2 (G) specimens possessed the lowest mean microhardness, while nHA-G (3B), G-Fl (4A), and L-G (5B) had significantly higher values. ESEM analysis showed an alteration in Group G and the obliteration of enamel micropores with remineralizing agents. The melting and fusion of enamel in laser subgroups were also observed. CONCLUSIONS: The findings indicated that using FV, nHA, or diode laser increased microhardness and maintained the integrity of the enamel microstructure. Therefore, applying preventive strategies should be considered in HNC radiotherapy.

Comparison of Remineralization Potential of Casein Phosphopeptide: Amorphous Calcium Phosphate, Nano-hydroxyapatite and Calcium Sucrose Phosphate on Artificial Enamel Lesions: An In Vitro Study.

Aim and objectiveTo evaluate and compare the remineralization potential of CPP-ACP, nano-hydroxyapatite, and calcium sucrose phosphate toothpaste on artificial enamel caries lesions by means of microhardness testing.Materials and methodsTwenty sound human primary molars, extracted for therapeutic reasons were selected for this study. From each tooth, two enamel specimens were prepared and embedded in acrylic resin blocks, and each block contains five tooth samples. After polishing, the baseline hardness of the enamel surface (KHN) was determined by Knoop microhardness testing. Then the specimens were randomly assigned into four groups (n = 10), according to the remineralizing agent used: group I: Control, group II: GC Tooth MousseTM (CCP-ACP), group III: AcclaimTM (nano-HAP), and group IV: EnaFix (CaSP). The specimens were then immersed in a demineralizing solution and post-lesion KHN values were obtained as baseline measurements. Later remineralizing agent was applied and after 7 days of remineralization, posttreatment KHN tests were conducted.ResultsData were analyzed using paired t- test, analysis of variance, and Tukey HSD test. Mean enamel surface microhardness (KHN) values after remineralization shows that group IV (EnaFixTM) had maximum hardness number (114.71 ± 12.27) followed by group III (Acclaim) (85.14 ± 22.82) and group II (GC Tooth Mousse) (56.42 ± 19.90). The difference was statistically significant (p < 0.001). Similarly the %SMHR was also highest in group IV (EnaFix), followed by group III (Acclaim) and group II (GC Tooth Mousse).ConclusionEnaFix (calcium sucrose phosphate) shows a maximum increase in the enamel surface microhardness followed by Acclaim (nano-HAP) and GC Tooth Mousse.Clinical significanceCalcium Sucrose Phosphate in toothpaste strengthened the enamel more than nano hydroxyapatite and CPP-ACP, and can be an alternative to the use of fluoride toothpaste in children.How to cite this articleSebastian R, Paul ST, Azher U, et al. Comparison of Remineralization Potential of Casein Phosphopeptide: Amorphous Calcium Phosphate Nano-hydroxyapatite and Calcium Sucrose Phosphate on Artificial Enamel Lesions: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(1):69-73.

Effect of Different Remineralization Protocols on Demineralized Enamel Surface Microhardness - In Vitro Comparative Study

Effect of Different Remineralization Protocols on Demineralized Enamel Surface Microhardness - In Vitro Comparative Study

Evaluation of Remineralizing Potential of CPP-ACP, CPP-ACP + F and β TCP + F and Their Effect on Microhardness of Enamel Using Vickers Microhardness Test: An In Vitro Study.

ContextThe change in understanding of dental caries which is now believed to be a reversible lesion has led to the change in its management.AimTo evaluate the remineralizing potential of three remineralizing agents [casein phosphopeptide (CPP)—amorphous calcium phosphate (ACP), CPP-ACP + F, and beta-tricalcium phosphate (β TCP) + F] and their effect on microhardness of enamel using Vickers microhardness test.Materials and methodForty freshly extracted premolars, extracted for orthodontic purpose were collected and specimen prepared. The specimens were equally divided into four groups. Baseline surface microhardness measurement was taken for the specimens. Demineralization of enamel was carried out by keeping the specimens in 20 mL of demineralizing solution for 72 hours, and microhardness was evaluated. Remineralizing agents CPP-ACP, CPP-ACP + F, and β TCP + F was applied to Group A, Group B, and Group C, respectively for 28 days and microhardness was evaluated again. Group D was kept as control group. Statistical analysis was done by One-way ANOVA test. Percentage microhardness recovery was calculated to evaluate the regain in microhardness after remineralization and thus assess the remineralizing efficacy of the agents.ResultsAfter demineralization surface microhardness of enamel decreased to the range of Vickers hardness number (VHN) 155-167 but after application of remineralizing agents surface microhardness for Group B was found to be highest, in other words, VHN 240.78 followed by Group C, in other words, VHN 214.29 and Group A the least VHN 197.90.ConclusionThe result of this study concludes that surface microhardness of enamel decreased after demineralization procedure and increased after application of all the remineralizing agents. The highest increase was seen in group tested with CPP-ACP + F followed by β TCP and least for CPP-ACP. The values for all the three groups were higher than the control so we can conclude that all the agents can be used as remineralizing agent with CPP-ACP + F being the best among the three.How to cite this articleBhat DV, Awchat KL, Singh P, et al. Evaluation of Remineralizing Potential of CPP-ACP, CPP-ACP + F and β TCP + F and Their Effect on Microhardness of Enamel Using Vickers Microhardness Test: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(S-2):S221-S225.

Evaluating the Effect of Diode Laser Irradiation on Microhardness of Bleached Enamel: An in Vitro Study

Aims: To investigate the effect of in-office dental bleaching techniques on the microhardness of enamel and the influence of post bleaching diode laser irradiation on the surface microhardness of bleached enamel. Materials and methods: Forty bovine teeth were prepared and then randomly allocated into two equal groups (n=20) according to bleaching technique as follows: CB: Conventional in-office bleaching technique and LB: Laser–assisted in-office bleaching technique. Each group was subdivided into two subgroups (n=10) according to laser irradiation setting as follows: C2: Conventionally bleached followed by diode laser irradiation at 2-Watt laser, C4: Conventionally bleached followed by diode laser irradiation at 4-Watt laser, L2: laser –assisted bleached followed by diode laser irradiation at 2-Watt laser and L4: Laser–assisted bleached followed by diode laser irradiation at 4-Watt laser. Vickers microhardness was assessed three times for all the specimens: before bleaching, 24 hours after bleaching and finally 24 hours after post bleaching diode laser irradiation. Paired samples t- test and independent samples t- test were utilized for statistical analysis. Results: Both bleached groups exhibited a significant decrease in micro harness after bleaching with no statistically significant differences between them. Post bleaching diode laser irradiation at 2Watt and 4Watt resulted in significant increase in microhardness with no significant difference was evident between them. Conclusions: Diode laser irradiation on bleached enamel had a positive influence on surface microhardness of enamel and it may represent a promising post bleaching treatment modality.

Development of a hydroxyapatite nanoparticle-based gel for enamel remineralization -A physicochemical properties and cell viability assay analysis.

Nano-hydroxyapatite (nHA) was synthesized from abalone mussel shells (Haliotis asinina) using a precipitation method, and gel HA-Abalone was developed using the carbomer materials with concentrations of 0, 10, 20, 30, and 40 wt%. The specimens used were 25 freshly extracted caries-free premolar teeth, and the treatment was done twice a day for 14 days. Gel HA-Abalone 20 wt%, with a crystallite size of 14.70±1.21 nm, was the best concentration to achieve the best remineralization (~863 VHN) of the superficial layer. Based on the results of cell viability assay on gel HA-Abalone 20 wt%, the growth of NIH/3T3 cells was inhibited beginning at a gel concentration of 1,000 µg/mL, and the half maximal inhibitory concentration (IC50) value was 1,497 µg/mL. Based on to the one-way analysis of variance (ANOVA), the result reflected statistically significant differences in the average of the cell viability and enamel surface microhardness values (p<0.05).

Effects of tooth bleaching protocols with violet LED and hydrogen peroxide on enamel properties

Background: This study evaluated the color change, enamel surface roughness and microhardness after different tooth bleaching protocols, using hydrogen peroxide (HP) and/or violet LED.Methods: Forty bovine specimens (7 × 7 × 2 mm) were randomly distributed into 4 groups: 35% HP, 6% HP, 6% HP + violet LED and violet LED alone. First, the specimens were stained with black tea and then submitted to two bleaching sessions of 30 min with an interval of 7 days. Color change (∆L*, ∆a*, ∆b* and ∆E00) after 24 h of each session and 1 week after the last session was evaluated. Enamel roughness and microhardness were evaluated immediately before the sessions, 24 h and 1 week after the last session. Data were evaluated by ANOVA for repeated measures and Bonferroni post-test or Kruskall-Wallis and Dunn tests (α = 0.05). Representative specimens from each group were analyzed by scanning electron microscopy.Results: 6% HP + violet LED and 35% HP showed the highest color change, while violet LED alone had the lowest results. Enamel roughness analyses showed that 6% HP + violet LED and 35% HP showed changes after two bleaching sessions. No differences were observed regarding enamel microhardness.Conclusions: The use of 6% HP + violet LED showed enhanced bleaching efficacy compared to 35% HP. However, violet LED used alone exhibited the lowest color change. 6% HP + violet LED and 35% HP promoted changes on enamel roughness, while no microhardness changes was observed for any group.

The Effect of Different Milk Products on Enamel Hardness: An In Vitro Study

Objectives: An in vitro study to assess the effect of different milk products on the hardness of enamel surfaces. Materials and Methods: Extracted primary and permanent teeth incisors (15 deciduous and 15 permanent) were collected and cleaned. The extracted teeth were then divided randomly into five groups (n=6 per group): G1- distilled water (control); G2- fresh milk (cow milk); G3- chocolate flavoured milk; G4- orange flavoured cultured milk; G5 - fruit lassi milk. The 10 days immersion cycles for the test products were performed thrice daily and were interspersed with exposure of the artificial saliva. Measurement of microhardness on the enamel surface microhardness measurement were performed at baseline, 5- and 10- day of experimentation using Vickers hardness test machine. The pH of each milk products was also assessed. The data were evaluated with repeated measures ANOVA test. Results: Group 4 had significant reduction in microhardness (p&lt;0.05) compared to the control group while Group 1 showed significant reduction (p&lt;0.05) in microhardness compared to all tested samples for day 5 and day 10. While for intergroup comparison, there was no difference in group 3 and group 2. However, there were significant difference between group 4 and group 5 with all other groups on day 10 (p&lt;0.05). Conclusion: Fresh milk showed to be more effective in increasing the enamel microhardness meanwhile orange culture milk has the highest reduction of enamel surface hardness. Thus, we suggest that milk product with low pH has high tendency in enamel erosion.

EFFICACY, TOOTH SURFACE MICROHARDNESS AND ROUGHNESS AFTER TREATMENT WITH COMBINATION OF LASER AND HOME BLEACHING PROTOCOL: AN IN VITRO STUDY

Teeth whitening or bleaching has pleased people with aesthetic concerns for long. To improve the efficacy of bleaching and reduce the ill effects on the tooth surface, a combination of power bleaching (PB) and home bleaching (HB) can be used. Objective. To compare the efficacy and effects of combinations of PB/laser bleaching (LB) and HB protocol on human natural tooth structure. Materials &amp;amp; methods: Eighty-eight permanent maxillary central incisors were randomly divided into four groups (n=22). After staining, teeth were bleached using different bleaching protocols: Group 0 (control), Group 1 (Laser White 20 46% hydrogen peroxide (HP) + Opalescence PF 20% carbamide peroxide (CP) – HB sequence for 3 days), Group 2 (Laser White 20 46% HP + Opalescence PF 20% CP – HB sequence for 7 days), Group 3 (Opalescence PF 20% CP – HB sequence for 14 days). Colorimetric measurement was performed, enamel surface roughness and microhardness were measured. Scanning Electron microscope (SEM) evaluation was done to compare the surface topography. Pre and post bleaching data were analysed using paired T-test. Multiple comparison between groups was carried out using one-way ANOVA complemented by Post hoc test (Bonferroni), with significance level set at P&amp;lt;0.05. Results: All protocols demonstrated significant efficacy to whiten stained enamel. All groups demonstrated significant increase in hardness (P&amp;lt;0.05). Surface roughness reduced significantly in Group 1 and 2. SEM showed that Group 1 had a similar microscopic surface appearance as unbleached enamel, while Group 3 had accentuated irregularities. Conclusion: LB followed by HB for 3 days is the most effective in whitening stained teeth with positive effects on tooth surface hardness while maintaining surface topography of dental hard tissues.