Enamel Surface Research Articles

Influence of bottled salad dressings on the development of enamel erosion in the presence or absence of salivary pellicle – An in vitro study

BackgroundAcidic beverages are believed to elevate the risk of enamel surface erosion. In addition to the intake of soft drinks, the increased consumption of salad dressings has been linked to a higher prevalence of dental erosion. Therefore, the current study aimed to investigate the influence of bottled salad dressings on the development of enamel erosion in the presence or absence of pellicle through in vitro experiment. MethodsPreliminary pH and calcium analyses of solutions were performed. Highest pH and calcium content was found for sandwich spread i.e., 4.69 and 55.4 mg/100 g grams, respectively. Eighty tooth specimens (measuring 4 × 4 × 3 mm) were prepared from extracted human premolars and randomly assigned to four groups (group 1: orange juice; group 2: eggless plain mayonnaise; group 3: sandwich spread; and group 4: thousand island dressing) with 20 samples in each group. Ten tooth specimens from each group were immersed in 20 ml of the respective solutions for 5 min (control group). The remaining ten tooth specimens from each group were submerged in 5 mL saliva vials for 3 min to facilitate salivary pellicle formation before being immersed in their respective solutions for 5 min (saliva-covered group). Pre and post-experimental assessments of enamel roughness and hardness were conducted using a surface roughness tester and Knoop Hardness indenter, respectively. ResultsOverall, enamel roughness was notably elevated in the control group, with the eggless plain mayonnaise (0.52 ± 0.38) and thousand island dressing groups (0.57 ± 0.29) showing a significant increase in surface roughness post-test (p = 0.05). Nevertheless, there was no significant difference in the enamel roughness between the groups. On the other hand, regardless of the presence/absence of the salivary pellicle, a marked decrease in enamel hardness was observed among all groups except for group 3 (sandwich spread) with a mean score of 311.5 ± 82.6 (p < 0.05). ConclusionA significant increase in surface roughness and reduction in enamel hardness was observed with salad dressings. However, in vitro formed salivary pellicle showed a protective effect against tooth erosion.

Gastroesophageal reflux disease as a risk factor of dental hard tissues erosions

Gastroesophageal reflux disease (GERD) is a common chronic disease leading to a spontaneous and regular retrograde flow of gastric and/or duodenal contents into the esophagus. Reflux of the gastric contents into the oral cavity refers to the extraesophageal presentation of the disease, which, in the absence of timely treatment, can result in erosion of dental hard tissue (EDHT) through repeated exposure of the dental tissue to acidic contents. EDHT are non-carious lesions of the dental hard tissues (mainly enamel, and in some cases dentin), induced by a chemical reaction involving acids, which results in demineralization processes. The incidence rates of EDHT in adult patients with GERD are 32.5–51.5%. The EDHT in GERD develops in stages. Initially, the gradual degradation of tooth pelicula happens when it gradually becomes decayed by repeated acidic attacks. The loss of the pelicula results in direct contact of hydrochloric acid refluxate with the enamel surface and initiation of its demineralization at pH &lt; 5.5 with dissolution of hydroxyapatite crystals. Given the high prevalence of GERD in the population, it seems important to update an integrated approach to the treatment of such patients, which involves pharmacotherapy provided by the gastroenterologist, as well as prevention and minimally invasive treatment of presentations in the oral cavity by the dentist. Patients with EDHT due to GERD need to maintain individual oral hygiene (use mouth washes with a neutral pH level, avoid abrasive toothpastes), use remineralization therapy at home applying remogels (Tooth Mousse), and also be observed by a dentist as part of the follow-up care. Minimally invasive treatment by the dentist involves restorations using composite tooth filling materials and ceramic veneers. It is reasonable to empirically use proton pump inhibitors twice a day for 3 months for the direct treatment of GERD in patients with EDHT.

Bleaching effect on bonding performance of composite to enamel.

This study aimed to assess the effects of dental bleaching on the immediate shear bond strength (SBS) of composite to enamel. Different bleaching methods and time intervals between bleaching and composite restoration were examined. A total of 45 enamel specimens were divided into three groups (n = 15) based on the applied bleaching protocol: in-office (A), at-home (B), and unbleached control (C). Groups A and B were then subdivided into three time intervals until bonding: 1, 3, and 7 days. The composite was bonded to enamel using self-etch adhesive technique and submitted to SBS testing. The enamel surface and adhesive interface were observed under scanning electron microscope (SEM). The highest average SBS was measured in the control (unbleached) group (31.1 ± 3.4). A significant difference in SBS was found between the control and in-office bleaching (p < .001), as well as between control and at-home bleaching (p = .034), while the difference between in-office and at-home bleaching methods was insignificant. In relation to the waiting period, a significant reduction in SBS (p < .001) was found 1 day post-bleaching. The weakest marginal sealing to enamel under SEM was observed also 1 day after bleaching. Both bleaching methods significantly reduced the SBS of composite to enamel, especially immediately after the bleaching procedure. Reduction in SBS is temporary and 3-day waiting period seems to be sufficient to reverse the adverse effects of bleaching. RESEARCH HIGHLIGHTS: SBS of composite to enamel is significantly reduced by bleaching procedures, especially immediately after bleaching. The reduction in SBS is temporary and reversible by delaying the restoration for a minimum of 3 days.

Cementum and enamel surface mimicry influences soft tissue cell behavior.

To test whether titanium surface roughness disparity might be used to specifically guide the behavior of gingiva fibroblasts and keratinocytes, thereby improving the quality of soft tissue (ST) integration around abutments. Titanium discs resembling the roughness of enamel (M) or cementum (MA) were created with normal or increased hydrophilicity and used as substrates for human fibroblasts and keratinocytes. Adhesion and proliferation assays were performed to assess cell-type specific responses upon encountering the different surfaces. Additionally, immunofluorescence and qPCR analyses were performed to study more in depth the behavior of fibroblasts and keratinocytes on MA and M surfaces, respectively. While enamel-like M surfaces supported adhesion, growth and a normal differentiation potential of keratinocytes, cementum-emulating MA surfaces specifically impaired the growth of keratinocytes. Vice versa, MA surfaces sustained regular adhesion and proliferation of fibroblasts. Yet, a more intimate adhesion between fibroblasts and titanium was achieved by an increased hydrophilicity of MA surfaces, which was associated with an increased expression of elastin. The optimal titanium implant abutment might be achieved by a bimodal roughness design, mimicking the roughness of enamel (M) and cementum with increased hydrophilicity (hMA), respectively. These surfaces can selectively elicit cell responses favoring proper ST barrier by impairing epithelial downgrowth and promoting firm adhesion of fibroblasts.

In Vitro Effect of Streptococcus mutans Biofilm Produced in Sugar-Free Coca-Cola on Enamel

ObjectiveSugary drinks such as Coca-Cola may expedite dental caries. For this reason, sugar-free drinks like Coca-Cola Zero Sugar (CZ) may be considered advantageous. This research aims to evaluate in vitro the CZ effect in the presence of Streptococcus mutans (S. mutans) biofilm on enamel demineralization. MethodsNinety-six human enamel slabs (4 × 4 mm) were used. S. mutans UA-159 72-hour biofilm was created over enamel surfaces. The specimens were soaked in CZ, HCl, or 10% sucrose in PBS solution, 3 times a day for 15 minutes over the course of 4 days. Viable counts (CFU/mL) and biofilm biomass (Crystal Violet staining) were evaluated. pH was measured after each exposure. After 4 days, Demineralization was evaluated clinically and by Vickers microhardness tests. Slabs were photographed using a stereomicroscope before and after exposure to caries-promoting conditions. ResultsSlabs that were soaked in CZ showed an increase in viable counts compared to control and almost similar counts with 10% sucrose in PBS solution exposures (1010and109CFUmL, respectivly). Biofilm biomass tests showed a 25% higher bacterial growth in the CZ group. CZ pH measures were the lowest and the only group to show a decrease in pH over time (pH ∼3). Enamel slabs that were evaluated clinically in the stereomicroscope postexposures had a chalky and matt appearance as opposed to their shiny appearance in the baseline evaluation. ConclusionsCZ creates a favourable environment for the growth of S. mutans. It may be suggested that even though CZ is sugar free it has a cariogenic effect on enamel. Clinical significanceClinicians need to educate patients that sugar-free carbonated drinks may be just as harmful as regular carbonated drinks, and hence avoided. This research emphasizes the harmful effect sugar-free carbonated drinks on teeth and sheds new light on their cariogenic potential.

Hydrated Calcium Silicate in Resin Composites for Prevention of Secondary Caries

Introduction and aimsThe gaps at the margins of restorative composite resin can increase as the carious process occurs underneath the materials, causing further demineralization along the tooth cavity wall. The aim of this study was to evaluate the effects of restorative resin composite containing hydrated calcium silicate (hCS) filler on enamel protection against demineralization by simulating microleakage between the test material and teeth in a cariogenic environment. MethodsThe experimental resin composites were composed of 70 wt.% filler, which was mixed with a glass filler and hCS in a weight ratio of 70.0% glass (hCS 0), 17.5% hCS + 52.5% glass (hCS 17.5), 35.0% hCS + 35.0% glass (hCS 35.0), and 52.5% hCS + 17.5% glass (hCS 52.5). A light-cured experimental resin composite disk was positioned over a polished bovine enamel disk, separated by a 30-µm gap, and immersed in artificial saliva with pH 4.0 for 15, 30, and 60 days. After the immersion period, the enamel disk was separated from the resin composite disk and evaluated using a microhardness tester, atomic force microscopy, and polarized light microscopy. The opposing sides of the enamel and resin composite disks were observed using scanning electron microscopy/energy dispersive X-ray spectrometry. ResultsThe enamel surface showed a significant increase in microhardness, decreased roughness, and remineralization layer as the proportion of hCS increased (P < .05). In the scanning electron microscopy image, the enamel surface with hCS 35.0 and 52.5 after all experimental immersion periods, showed a pattern similar to that of a sound tooth. ConclusionsThe results demonstrated that increasing the hCS filler level of restorative resin composites significantly decreased enamel demineralization. Clinical relevanceHydrated calcium silicate laced restorative resin composites may be a promising dental biomaterial for protecting teeth against demineralization and preventing secondary caries around restorations.

Effect of the calcium silicate and sodium phosphate remineralizing products on bleached enamel.

This study evaluated the effect of calcium silicate and sodium phosphate (CSSP) dentifrice and serum on the surface of enamel bleached with hydrogen peroxide (H2O2). A total of 160 bovine enamel slabs were bleached with 35% H2O2 and treated with sodium fluoride (NaF) dentifrice-GI, CSSP dentifrice-GII; CSSP dentifrice + CSSP serum-GIII, or NaF dentifrice + NaF gel-GIV. The dentifrices were applied using a brushing machine three times daily for 7 days. After brushing, sodium phosphate gel and CSSP serum were applied. The microhardness (KNH, n = 14), surface roughness (Ra, n = 14), energy dispersive spectroscopy (n = 6), and scanning electron microscopy (n = 6) were assessed at t0 (before bleaching), t1 (after bleaching), and t2 (after postbleaching treatments). The data were subjected to a two-way analysis of variance and Bonferroni's test. The KNH decreased at t1 (P < 0.001) but recovered at t2 for all treatments, although only GII showed restored baseline values (P = 0.0109). The surface roughness increased at t1 (P < 0.001) and reduced at t2 (P < 0.001) for all groups, with no significant differences among groups. Enamel composition and morphology did not differ after the treatments, except for silicon accumulation in GIII. Postbleaching treatment with CSSP dentifrice and serum yielded superior remineralizing effects on bleached enamel.

Qualitative and quantitative evaluation of enamel surface roughness and remineralization after interproximal reduction: An in vivo study

Interproximal reduction (IPR) damages the caries protective superficial layer of the enamel, making the enamel surface prone to caries because of the increase in surface roughness. Remineralizing solutions can help in preventing these undesirable side effects. Therefore, this study aimed to compare the effect of nanohydroxyapatite (nHAp) and sodium fluoride (NaF) application on enamel remineralization after IPR and to evaluate changes in surface roughness, composition, and microhardness of the treated enamel. A total of 25 patients with Angle's Class I malocclusion, requiring 4 premolar extractions, were selected and randomly divided into 5 groups (n= 5). Group 1 served as the control. In group 2, the extraction of premolars was done immediately after IPR, and in group 3, the extraction of premolars was done 3 months after IPR. In group 4, the extraction of premolars was performed 3 months after IPR with weekly application of nHAp serum. In group 5, the extraction of premolars was performed 3 months after IPR, along with once-a-month application of NaF varnish. The proximal reduction of premolars in all the groups was done using Strauss IPR burs (Strauss Diamond Instruments, Palm Coast, Fla). The extracted teeth were sectioned, and the enamel surfaces were subjected to energy-dispersive x-ray spectroscopy to evaluate elemental composition. Vicker's microhardness test was used to evaluate enamel hardness and atomic force microscopy for enamel surface roughness. Descriptive statistics were calculated for the 5 groups using a 1-way analysis of variance, and Tukey's multiple post-hoc test was used for intergroup comparison. Calcium-to-phosphorous ratio, enamel microhardness, and surface roughness were found to be closest to untouched enamel in patients treated with nHAp, followed by patients who were treated with NaF. A lower calcium-to-phosphorous ratio and weakened and roughest enamel surface was seen in teeth, which were extracted immediately after IPR. Among the remineralizing agents tested, nHAp serum can be recommended for better remineralization of enamel surfaces after IPR.

Formulation and Evaluation of Characteristics, Remineralization Potential, and Antimicrobial Properties of Toothpaste Containing Nanohydroxyapatite and Nanosilver Particles: An In Vitro Study.

The current study is aimed to evaluate the antimicrobial and remineralizing properties of toothpaste containing nanosilver and nanohydroxyapatite (NH-NS TP). The toothpaste was prepared by incorporating NH-NS TP into a toothpaste base. Following this, a physicochemical analysis of the prepared toothpaste was carried out. The toxicity against human gingival fibroblast (HGF-1) cells was assessed. The antimicrobial activity of the toothpaste was evaluated against Streptococcus mutans and Escherichia coli using the disk diffusion method. Subsequently, 15 selected human premolar teeth extracted for orthodontic purposes were used to measure the remineralization potential. The surfaces of the selected teeth were demineralized using a prepared demineralizing solution [323.4 mg of calcium chloride (CaCl2), M450 µL of calcium acetate (CH3COO)2Ca, 300 mg of potassium dihydrogen phosphate (KH2PO4) at pH 4.4-4.7] for 72 hours and were subjected to a toothbrush simulator applying the prepared toothpaste. The remineralization potential was evaluated by measuring the microhardness of the enamel surface before and after treatment with the toothpaste. Further, the remineralization potential was assessed based on scanning electron microscopy (SEM) imaging accompanied by energy-dispersive X-ray spectroscopy. The results showed that the NH-NS TP had significantly greater antimicrobial activity compared to the control toothpaste and no toxicity against HGF-1 up to 40 µg. Approximately, 7-9 mm inhibition zone against S. mutans and 4-6 mm inhibition against E. coli was achieved. Additionally, the toothpaste significantly increased (31.4%) the microhardness of the enamel surface, indicating its potential for remineralization. The SEM images revealed the presence of regular deposits, mostly pertaining to the demineralized spots, resulting in a regained smooth surface. Following this, physicochemical analysis of the prepared toothpaste was carried out, resulting in a pH of 7.38 and showing good extrusion, frothing, and organoleptic properties. Additionally, the toothpaste significantly increased the microhardness of the enamel surface, further indicating its potential for remineralization. NH-NS TP may provide a promising approach for improving oral health by enhancing antimicrobial efficacy and promoting enamel remineralization, while exhibiting reduced toxicity. Sevagaperumal A, Joel JR Periyasamy S. Formulation and Evaluation of Characteristics, Remineralization Potential, and Antimicrobial Properties of Toothpaste Containing Nanohydroxyapatite and Nanosilver Particles: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(6):630-636.

Erosion protective properties of the enamel pellicle in-situ

Objectives: Previous studies on short- and long-term pellicles showed that the enamel pellicle provides partial protection against erosion. The aim of the present study was to investigate the protective properties of clinically relevant pellicles formed within 2 to 24 h. The hypothesis was that factors such as pellicle formation time, intraoral location, and acidic challenge severity would not influence the erosion-protective properties of the pellicle.Methods: Six subjects participated in the study. Bovine enamel specimens were prepared and intraorally exposed at buccal or palatal sites for 2, 6, 12, and 24 h to allow pellicle formation, followed by erosion using 0.1 % or 1 % citric acid. Calcium release and surface microhardness were measured, and specimens were analysed using scanning and transmission electron microscopy. Quantitative data were statistically analysed with three-way ANOVA and Tuckey's multiple comparison test (p = 0.05).Results: Pellicle formation time and intraoral location did not significantly influence the erosion-protective properties of the pellicle, while citric acid concentration significantly affected enamel erosion. The pellicle thickness increased with longer formation times and on buccal sites, but decreased or was entirely removed following treatment with 0.1 % or 1 % citric acid, respectively. The enamel surface exhibited a characteristic erosion pattern.Conclusions: This study underscores the importance of investigating pellicle properties within the critical 2- to 24-h timeframe and highlights the significance of pellicle thickness in acid resistance.Clinical significance: These findings provide valuable insights into the factors influencing the protective properties of enamel pellicles and could guide preventive measures in dental practice.

Comparative Assessment of the Shear Bond Strength of Ceramic Brackets Bonded to the Enamel Surface with a Self-adhesive System.

Objectives: This study aimed to evaluate the shear bond strength of ceramic brackets bonded to the enamel surface using Vertise Flow, with or without the application of phosphoric acid. Materials and Methods: Forty-five extracted human premolar teeth were randomly assigned to three groups (N=15) based on the adhesive used for bonding: 1) Transbond XT, etch, and bond; 2) Vertise Flow; 3) Etch and Vertise Flow. After a 500-round thermocycling procedure, the shear bond strength was measured using a universal testing machine. The samples were then evaluated under a stereomicroscope to determine failure modes, and the Adhesive Remnant Index (ARI) was measured for each group. The data were analyzed with one-way ANOVA and post-hoc Tamhane at a significance level of P<0.05. Results: The highest shear bond strength values were observed in the Transbond XT (13.5±5.38MPa), acid etch and Vertise Flow (11.2±2.89MPa), and Vertise Flow (6.2±3.16MPa) groups, respectively, in descending order. The Vertise Flow group exhibited a significantly lower shear bond strength value compared to the other two groups, with no significant difference between the latter two. Conclusion: While all three study groups demonstrated clinically acceptable shear bond strength values, Vertise Flow showed lower values compared to the other two adhesives. The Vertise Flow composite resin system, whether used alone or with acid etching, remains a suitable choice for bonding ceramic brackets, offering the advantage of a simplified bonding procedure.

Comparison of Bond Strength Between Two Resin Cement Types and Additive Manufacturing or Cast Cobalt-Chromium Alloys.

To compare the bond strength of two types of resin cement to that of additive manufacturing (AM) or cast cobalt-chromium (Co-Cr) alloys. Two types of resin luting cement, composite resin and methyl methacrylate (MMA), were bonded to AM or cast Co-Cr alloys, and shear bond tests were performed after seven days of storage in distilled water at 37°C. Co-Cr alloy adhesive elements AM to the enamel surface of the labial aspect of a bovine mandibular central incisor crown were bonded with two types of resin luting cement and subjected to 1,000 cycles of storage in water for one day and 28 days or thermal cycling, followed by shear bonding tests. Residual cement on the metal and enamel surfaces after the bonding tests was evaluated using an optical microscope. The normality of the results was evaluated using statistical software Statcel4, analysis of variance, or Kruskal-Wallis test, depending on normality, and multiple comparison tests were performed using the Tukey-Kramer or Steel-Dwass tests. After one day, the shear bond strength (SBS) was 25.9 MPa for Panavia V5 (PV; Kuraray Noritake Dental Corporation, Niigata, Japan) and 23.5 MPa for Super-Bond (SB; Sun Medical Corporation, Shiga, Japan), with no significant difference between the two cement types (P > 0.05). After 28 days, the SBS decreased to 4.1 MPa for PV and 6.7 MPa for SB, showing a significant difference between the two cements (P < 0.05). Following 1,000 thermal cycles, the SBS was 2.0 MPa for PV and 5.6 MPa for SB, with SB exhibiting a significantly higher value (P < 0.05). The adhesive strength was significantly lower after 28 days of storage and thermal cycling compared to after one day of storage (P < 0.05). The Co-Cr alloy exhibited more residual cement on the enamel surface due to interfacial fracture with the resin cement. The Co-Cr alloy showed more residual cement on the enamel surface due to interfacial fracture with the resin cement. MMA-based resin cement showed optimal bond strength and may be suitable for clinical use in computer-aided design (CAD)/computer-aided manufacturing (CAM) orthodontic appliances.

Enamel surface roughness following debonding resin clean up using high speed air-turbine and electric handpieces. In vitro study

BackgroundHigh speed electric handpieces have recently been growing in popularity among dental professionals. Advantages include smoother surface preparation and increased cutting efficiency.AimThe primary objective was to compare enamel surface roughness following resin cleanup after bracket debonding using highspeed air turbine versus electric handpiece. The secondary objective was to record the time needed for resin-clean up.MethodForty deidentified freshly extracted human premolars were cleaned and sectioned at the cement-enamel junction. The crowns were embedded in acrylic blocks. Enamel surface roughness parameters (Ra, Rz, Rp and Rv) were measured using a stylus profilometer. Brackets were bonded using a light-cure orthodontic adhesive and stored in distilled water for 24 h. Following bracket debonding, the specimens were randomly divided into 2 groups: First group: resin clean-up was carried out using a 12-fluted carbide bur mounted on a high-speed air turbine; and second group: where an electric handpiece was used. Surface roughness parameters were measured following resin clean up and after polishing using pumice and a rubber cup. Time needed for resin clean-up was recorded. Differences in enamel surface roughness and time between groups were compared using repeated measures ANOVA and independent samples t-test, respectively at P ≤ 0.05.ResultsThe electric handpiece groups showed significantly higher values for Ra, Rz and Rp both following resin cleanup and polishing. Time taken for resin cleanup was significantly longer for the electric handpiece group.ConclusionConsidering both surface roughness and time, electric handpiece do not seem to add greater effectiveness or efficiency to resin cleanup following orthodontic bracket debonding.

In-Vitro Investigation of the Shear Bond Strength of Different Orthodontic Adhesives to Enamel.

The shear bond strength (SBS) of orthodontic adhesives to enamel is a critical factor in the success of orthodontic treatment. Various adhesives are available in the market, each with different trade names and claimed properties that could influence their bond strength. Understanding these differences is essential for clinical decision-making. In this in-vitro study, 60 freshly extracted human premolars were collected and randomly divided into four groups: Group A (Adhesive X-Trade Name: BondPlus), Group B (Adhesive Y-Trade Name: OrthoBond), Group C (Adhesive Z-Trade Name: PowerBond), and Group D (Control). The enamel surfaces were cleaned, polished, and etched following standard protocols. Orthodontic brackets were bonded to the teeth using the respective adhesives according to the manufacturer's instructions. A universal testing machine was employed to measure the SBS, and the data were analyzed using ANOVA with post-hoc tests. The mean SBS values (MPa) were as follows: Group A = 15.2, Group B = 14.8, Group C = 16.5, and Group D (Control) =10.3. Statistical analysis revealed significant differences among the groups (P < 0.05). Post-hoc tests indicated that Group C exhibited significantly higher SBS compared to the other groups. Our findings suggest that among the orthodontic adhesives tested, PowerBond demonstrated superior shear bond strength to the enamel. However, further research is warranted to explore other aspects of adhesive performance and clinical implications.

Comparative Evaluation of Dental Enamel Microhardness Following Various Methods of Interproximal Reduction: A Vickers Hardness Tester Investigation.

Interproximal enamel reduction, also known as stripping, is a common orthodontic procedure that reduces the mesiodistal diameter of teeth, allowing for a balance of available space in dental arches. The aim of this study was to assess the enamel surface microhardness resulting from the application of currently available methods for interproximal reduction. Forty-two extracted human permanent teeth were divided into six different groups, each subjected to a therapeutic stripping procedure using various methods (i.e., diamond burs, abrasive strips of 90 μm, 60 μm, 40 μm, and 15 μm, and abrasive discs). Stripping was performed by a single individual in accordance with the manufacturers' recommendations for the various systems used. One of the proximal faces of the tooth underwent IPR, while the other side remained untreated for control. The hardness of the enamel surface was measured using a Vickers hardness tester. The control group achieved the hardest enamel surface (354.4 ± 41.02 HV1), while the lowest was observed for enamel surfaces treated with 90 µm abrasive strips (213.7 ± 118.6). The only statistically significant difference was identified in comparisons between the values measured for the control group and those obtained after stripping with diamond burs (p = 0.0159). Enamel microhardness varied depending on the stripping instrument used, but no statistically significant differences were found (p > 0.05). Optimal microhardness values, close to those of healthy enamel, were achieved after mechanical treatment with 15 µm abrasive strips and abrasive discs. Dental stripping is a safe therapeutic procedure that has a relatively minor influence on the microhardness of surface enamel.

Efficacy of the Probiotic L. brevis in Counteracting the Demineralizing Process of the Tooth Enamel Surface: Results from an In Vitro Study.

Enamel plays an essential role in protecting the underlying layers of the human tooth; therefore, preserving it is vital. This experimental study aimed to evaluate the potential ability of L. brevis to counteract the action of a demineralizing agent on dental enamel morphology and mineral composition in vitro. The sample consisted of 12 healthy human posterior teeth. The coronal portion of each tooth was subdivided into two equal parts longitudinally. The specimens were randomly divided into four groups: artificial saliva, L. brevis suspension, demineralizing agent (DA), and DA plus L. brevis. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to evaluate the surface micromorphology and the mineral content, respectively. The statistical analysis was conducted using a one-way ANOVA, followed by Tukey's post hoc test. SEM analysis did not highlight significant changes in the enamel microstructure of L. brevis-treated specimens compared to the control. DA-induced damage to the enamel structure was drastically reduced when the specimens were contextually exposed to the probiotic. The treatment with DA substantially reduced the weight % of crucial enamel minerals, i.e., Ca and P. Notably, the probiotic was able to reverse the demineralization process, bringing Ca and P weight % back to basal levels, including the Ca/P ratio. The findings indicate that L. brevis is able to efficiently protect the dental enamel surface from the damage caused by DA and increase the enamel resistance to demineralization. Overall, L. brevis confirms its efficacy in preventing or counteracting the action of carious lesions through a novel mechanism that protects the tooth surface under a chemical challenge that mimics the caries process.

The Potential of QP3VH-Chitosan Peptide as Biomimetic Remineralization in Early Dental Caries Treatment: An In Vitro Study.

The development of remineralization biomimetics using organic peptide molecules is expected to resemble the hydroxyapatite (HA) mineralization process in tooth enamel. The development of an amelogenin derivative peptide combined with antimicrobial peptide was designed, resulting in QP3VH. This combination then was mixed with chitosan as a carrier. This study aimed to evaluate the biomimetic efficacy of QP3VH as a remineralizing agent combined with chitosan. Fifty deciduous mandibular incisor enamel samples were used in this study. The artificial enamel lesions were created on a buccal surface and were randomly assigned to five groups of 10 each according to the remineralizing agent used: QP3VH, NaF, QP3VH + NaF, QP3VH + CS (QP3VH + chitosan), and saline distilled water (SDW). Each group was performed pH cycling for seven days. Enamel surface morphology and evaluation of mineral content Ca/P (calcium and phosphate) using scanning electron microscopy and energy dispersive X-ray analysis. The assessment was carried out, after demineralization, and after application with remineralization agents. Data were analyzed using a one-way analysis of variance followed by least significance difference post-hoc test. The paired t-test was utilized to compare the demineralization and remineralization results. The significance level used was 95%. The remineralized group exhibited a significant increase in calcium and phosphate content on the enamel surface (p <0.05), and QP3VH + CS produced the maximum Ca/P mass percent after remineralization. Combining QP3VH with chitosan produces greatest remineralization than QP3VH, QP3VH + NaF, Naf, and SDW; therefore, QP3VH peptide has potential as a remineralizing agent, in the future.

Assessment of changes in enamel colour following fixed orthodontic therapy using an advanced spectrophotometer: An in vivo study.

Any manipulation of the surface of natural teeth may result in a variation of their colour. The fixed orthodontic treatment (FOT) is one such procedure which alters the enamel surface during the procedure. To clinically evaluate the colour changes in teeth associated with comprehensive FOT (to compare the changes in test and control groups) and to determine the relationship of age and gender on enamel colour due to FOT by using an advanced spectrophotometer. The selection of sixty patients for the study was done randomly and among these thirty patients who underwent the FOT as the case group, the other thirty patients who did not need FOT, were the control group. The recordings of spectrophotometric data were done in a standardized manner for all patients in the labial circular region of every anterior tooth, following debonding and cleaning operations, and before bracket bonding. The Commission Internationale de l'Eclairage's L*, a*, and b* (lightness, red/green, and blue/yellow) tooth-type characteristics were used to measure color, and the associated color differences (DE) between the groups were computed. One-way ANOVA (a < 0.05) and the paired t-test were used to evaluate any changes in these color characteristics. Fixed orthodontic treatment is associated with changes in colour parameters. L* values decreased (P< 0.001), while a* and b* values increased (P< 0.001) at the end of treatment. All measured tooth types showed significant colour change (DE); their mean differences ranged from 1.64 to 2.96 DE units. Fixed orthodontics can change the natural colour of teeth. The CIE colour parameters L*, a*, and b* of natural teeth showed statistically significant differences after debonding the orthodontic appliances. The L* values decreased making the teeth look darker. The adolescent and male patients had more tooth colour changes than the adult and female groups.

Enamel Remineralisation with a Novel Sodium Fluoride-Infused Bristle Toothbrush.

This study aims to investigate whether toothbrushes with fluoride-infused bristles have any (re)mineralisation effects on bovine enamel. Bovine incisors (N = 160) were extracted, and the buccal side of the crown was cut into dimensions of ~5 mm × 5 mm with a low-speed saw. These specimens were randomly allocated into four groups: half (80 teeth) were stored in demineralising solution (DM), and the other half were stored in deionised water (DW) for 96 h. Then, they were brushed with a force of 2.0 ± 0.1 N for five min with a manual toothbrush with either fluoride-infused (TF) or regular (TR) bristles. Microhardness (Vickers), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) were used to investigate the surfaces of the bovine enamel specimens before and after brushing. Two-way ANOVA was used to analyse the hardness data, and the pairwise comparison method was used to analyse the Ca/P ratio, for each group at α = 0.05. The results show that brushing with either of these toothbrushes increased the Vickers microhardness on DM and DW enamel (p < 0.001), whereas hydroxyapatite was revealed in all groups by XRD. The DM samples showed a significant increase (p < 0.05) in the Ca/P ratios after brushing with TR and TF. Conversely, under DW conditions, these ratios decreased significantly after brushing. In terms of the F atomic%, TF increased significantly. SEM revealed mineral deposition in the DM groups after toothbrushing. To conclude, toothbrushing effectively induces the microhardness of sound and demineralised enamel, while fluoride-infused bristles might be able to retain fluoride on the enamel surface.

The Influence of Thermocycling Testing on Enamel Microcracks following the Metal Orthodontic Brackets Debonding

Enamel microcracks (EMCs) arising during the removal of metal orthodontic brackets represent a considerable challenge in dentistry. This in vitro study aims to explore the impacts of thermocycling, the types of orthodontic bonding agent, and curing techniques on the enamel surface of the tooth structure following the debonding of orthodontic metal brackets. It also examines the incidence, number, length, and direction of EMCs on the buccal surface of the tooth. Additionally, the study compares adhesive remnant index (ARI) scores and bracket failure post-debonding. Forty extracted human maxillary canines were divided into ten groups, including intact enamel negative controls (groups 1, 2) and groups (3–8) with metal brackets bonded using two different bonding agents and curing techniques. Following bonding, half of the groups underwent thermocycling testing. EMCs, ARI scores, and bracket failure modes were evaluated. The formation, length, and direction of cracks did not significantly differ among groups, regardless of experimental conditions. Thermocycling had no significant effect on ARI scores or bracket failure modes. However, significant variations were observed among curing technique groups, with seventh-generation bonding agents demonstrating potential effectiveness in achieving complete adhesive removal. The study underscores the importance of considering bonding agent systems and curing protocols to optimize bond outcomes and minimize the risk of metal bracket failure in orthodontic treatment.