A method to measure clinical erosion: the effect of orange juice consumption on erosion of enamel

Assessment of Erosive Effect of Various Beverages on Esthetic Restorative Materials Used in Primary Teeth: An In Vitro Study

AIM

The purpose of the current study was to evaluate the erosive impact of various beverages on the esthetic restorative materials utilized in primary teeth.

MATERIALS AND METHODS

One hundred and twenty primary molars indicated for serial extraction or over-retention reason with sound buccal surfaces were collected. One millimeter above the cemento-enamel junction, standard Class V cavities were prepared. Following cavity preparation, all teeth were randomly assigned (20 samples per group for each beverage) to one of the three experimental groups based on the type of filling materials: group I: resin-modified glass ionomer cement (GC), group II: nanocomposite resin and group III nanohybrid ormocer-based composite. The samples were kept suspended in various containers containing 250 mL of each orange juice and cola at a temperature of 37°C for three hours per day and rest of day in distilled water. This procedure was repeated for 15 days. Using a 3D optical profilometer, a profilometric reading was recorded for each specimen.

RESULTS

The minimum surface roughness was found in nanohybrid ormocer‑based composite (1.816 ± 0.16 and 1.302 ± 0.08) followed by resin-modified glass ionomer cement (3.101 ± 0.12 and 2.946 ± 0.09) and nanocomposite resin (5.242 ± 0.20 and 4.488 ± 0.16) after immersed in the cola and orange juice, respectively. And there was a statistically significant difference found between the different esthetic restorative materials in both media.

CONCLUSION

On conclusion, the current investigation demonstrates that when exposed to both beverages, the erosive effect was much lesser in nanohybrid ormocer-based composite, followed by resin-modified glass ionomer cement and nanocomposite resin.

CLINICAL SIGNIFICANCE

Consuming high-calorie, low pH acidic foods and beverages such as carbonated beverages and fruit juices can lead to erosion, a frequent condition that results in irreparable damage to dental hard tissues and early deterioration of dental restorations.

Assessment of demineralized tooth lesions using optical coherence tomography and other state-of-the-art technologies: a review

Tooth demineralization is one of the most common intraoral diseases, encompassing (1) caries caused by acid-producing bacteria and (2) erosion induced by acid of non-bacterial origin from intrinsic sources (e.g. stomach acid reflux) and extrinsic sources (e.g. carbonated drinks). Current clinical assessment based on visual-tactile examination and standardized scoring systems is insufficient for early detection. A combination of clinical examination and technology is therefore increasingly adapted. This paper reviews various procedures and technologies that have been invented to diagnose and assess the severity of tooth demineralization, with focus on optical coherence tomography (OCT). As a micron-resolution non-invasive 3D imaging modality, variants of OCT are now available, offering many advantages under different working principles for detailed analytical assessment of tooth demineralization. The roles, capabilities and impact of OCT against other state-of-the-art technologies in both clinical and research settings are described. (139 words).

Quantitative Analysis and Effect of SDF, APF, NaF on Demineralized Human Primary Enamel Using SEM, XRD, and FTIR

Introduction

Topical fluoride therapy has proven benefits in the prevention of demineralization. Tooth enamel has shown a great potential for remineralization with an application of topical fluorides if administered at an appropriate time. In an effort to find an effective remineralizing agent, a novel fluoride agent silver diamine fluoride (SDF) has emerged as a potent caries arresting as well as caries preventing agent.

Aim and objective

The present study was aimed at determining the primary tooth enamel resistance to demineralization after topical application of three fluoride agents SDF, APF, and NaF.

Materials and methods

Enamel specimens were prepared from 40 caries-free primary molars. These specimens were randomly allocated into three groups of 10 specimens each and they were treated by different topical fluorides namely: Group I-SDF, group II-Acidulated phosphate fluoride (APF), group III-Sodium fluoride. Three enamel specimens from each group were placed on custom-made acrylic blocks with 5 × 5 mm of an exposed window for scanning electron microscope (SEM) evaluation and rest of the specimens were ground into a fine powder for X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. The tooth blocks and treated samples were subjected to the demineralization process for 168 hours. They were then qualitatively assessed to evaluate their resistance to demineralization using SEM, XRD, and FTIR.

Results and conclusion

Morphologically, the enamel of all groups specimens was mostly smooth with some groves and microporosities. Chemically, the Ca/P molar ratios of all groups were similar with slight variations. Structurally, the crystalline phases found in enamel by powder XRD were hydroxyapatite and carbonate apatite; and there was a higher amount of incorporated type B carbonate than type A carbonate as evidenced by FTIR. The study concludes that topical application of a 38% SDF solution can inhibit demineralization of enamel.

How to cite this article

Jabin Z, Nasim I, Vishnu Priya V, et al. Quantitative Analysis and Effect of SDF, APF, NaF on Demineralized Human Primary Enamel Using SEM, XRD, and FTIR. Int J Clin Pediatr Dent 2021;14(4):537-541.

Erosion of CAD/CAM restorative materials and human enamel: An in vitro study

This in vitro study used the same frequency and duration of acid contact as a previous in situ/in vivo study to evaluate the effect of erosion on CAD/CAM restorative materials and human enamel and to compare the effects of in vitro and in situ/in vivo acid challenges on CAD/CAM restorative materials and human enamel. The CAD/CAM restorative materials (IPS e.max CAD, Lava Ultimate, and PMMA block) and human enamel were eroded by immersion in 150 ml of cola drink for 14 days (4 × 5 min/day). The surface microhardness and surface roughness of the specimens were measured at baseline (T1), day 7 (T2), and day 14 (T3). The substance losses were measured at T2 and T3. The data were statistically analyzed using repeated measures ANOVA and Bonferroni's test (α = 0.05). Erosion significantly decreased the surface microhardness of the CAD/CAM restorative materials and human enamel (all P < 0.001). The overall percentage of surface microhardness loss (%SMH_l) of the PMMA block and enamel due to in vitro erosion was significantly higher than that due to in situ/in vivo erosion (P = 0.02 and P < 0.001, respectively). Consistent with in situ/in vivo erosion, the surface roughness and profile of the tested restorative materials remained unchanged after in vitro erosion. A significant increase in the surface roughness and substance loss was observed for enamel after in vitro erosion (all P < 0.001). The overall substance loss of enamel due to in vitro erosion was significantly higher than that due to in situ/in vivo erosion (P < 0.001). In conclusion, erosion decreased the surface microhardness of the CAD/CAM restorative materials and human enamel. Moreover, erosion negatively influenced the substance loss and surface roughness of human enamel. For the substance loss of enamel and %SMH_l of PMMA block and enamel, the in vitro erosive effects were approximately 1-2 times greater than the in situ/in vivo effects. However, for the surface roughness and profile of the CAD/CAM restorative materials, no significant difference was found between in vitro and in situ/in vivo erosion.

Effect of dentifrice slurry abrasivity and erosive challenge on simulated non-carious cervical lesions development in vitro

PURPOSE

To investigate the effect of slurry abrasive levels and acidic challenges on the development of non-carious cervical lesions.

METHODS

Ninety-six extracted upper premolars were affixed in pairs to acrylic blocks and had their root surfaces covered by acrylic resin except for 2 mm from the cemento-enamel junction. The specimens were distributed into six groups (n = 8 pairs) based on two experimental factors: (1) slurry abrasivity level [low/medium/high] and (2) citric acid challenge [yes/no]. Specimens were brushed for 5,000, 15,000, 35,000, and 65,000 strokes. Volume loss (VL) was determined based on optical profilometry scans of specimens impressions at the baseline and at subsequent brushing levels. Data were analyzed using repeated measures analysis of variance and Bonferroni pairwise comparison (α = 0.05).

RESULTS

Higher VL values were associated with high-abrasivity slurries relative to low- and medium-abrasivity slurries (P < 0.001). Increasing the slurry abrasivity level increased the VL regardless of the acidic challenge, which did not have a significant effect (P = 0.184). After 65,000 strokes, significant VL was recorded in all groups relative to preceding brushing levels (P < 0.001).

CONCLUSION

Higher values of time-dependent surface loss were associated with increased dentifrice slurry abrasivity, regardless of the citric acid challenge.

Nanoscale effects of beverages on enamel surface of human teeth: An atomic force microscopy study

Dental erosion has become a prevalence disease and attracted increasing attention worldwide. In this research, we quantitatively evaluate the mechanical and morphological changes in the very early stages of softening and weakening of human enamel surfaces induced by soft drinks using atomic force microscopy (AFM). With an increase of the immersion time in soft drinks, we found a significant increase of surface roughness (R_q) of the enamel surface. The prismatic structure of enamel was clearly observed after a 1-h immersion in Coca-Cola®, which shows its strong erosion effect. According to the elastic modulus mapping images obtained by AFM, a considerable decrease of elastic modulus (E) of enamel surface has been found as the enamel surface structures are etched away by soft drinks. A high surface roughness of enamel will result in a high chance of cavities due to easier bacterial adhesion on rougher surface, while a drastic deterioration of the mechanical properties of the enamel will weaken its protection property. Our findings show the serious influence of acidic drinks on enamel surface at the very beginning stage of etching process, which is quite meaningful for people to prevent dental erosion and keep dental health.

Eroded enamel rehardening using two intraoral appliances designs in different times of salivary exposure

BACKGROUND

The aim of this study was evaluated the eroded enamel rehardening potential using upper palatal and lower buccal removable appliances in different times of salivary exposure (30 min, 1h, 2h, 12h) after a single erosive challenge event.

MATERIAL AND METHODS

After initial surface hardness evaluation, bovine enamel blocks were eroded in vitro (0.01 M hydrochloric acid, pH 2.3, 30 seconds), selected (n = 160) and randomly assigned to the two appliance designs and twenty volunteers. Four enamel blocks were inserted in each removable appliance. On the in situ phase, the volunteers were instructed to use the upper palatal and lower buccal appliances simultaneously for 12 nonconsecutive hours. After each predetermined period of time of salivary exposure, the enamel blocks were removed from the appliances for immediate evaluation of surface hardness, enabling percentage of surface hardness recovery calculation (%SHR). The data were analyzed using two-way ANOVA and Tukey's test (α=5%).

RESULTS

The results showed no difference in the degree of enamel rehardening by the upper palatal or lower buccal appliances (p >0.0001). Regarding the time of use of the appliances, it was demonstrated that 30 minutes (upper = 21.12%, lower = 19.84%) and 1 hour (upper = 35.69%, lower = 30.50%) promoted lower hardness recovery than two hours (upper = 44.65%, lower 40.80%) of salivary exposure (p<0.0001). The use of 12 hours (upper = 49.33%, lower = 49.00%), including the sleeping time of the volunteers did not increase the %SHR.

CONCLUSIONS

The location of the appliance does not influence the re-hardening ability of saliva and the use of intraoral appliances for 2 hours seems to be appropriate for partial rehardening of the softened enamel surface. Key words:Tooth erosion, in situ, saliva, tooth remineralization.

100% Fruit Juice and Dental Health: A Systematic Review of the Literature

Background: The objective of this systematic review was to assess the scope and breadth of publicly available prospective cohort and randomized controlled trial (RCT) literature on 100% fruit juice and dental caries or tooth erosion in humans.

Methods: We performed a systematic search in MEDLINE/PubMed, EMBASE, and Web of Science for studies published from inception through May 2018, and the Cochrane Library databases for reports published through January 2018. Prospective cohort studies or RCTs conducted on dental health and 100% fruit juice, and published in English were selected. No restrictions were set for age, sex, geographic location, or socioeconomic status.

Results: Eight publications representing five independent prospective cohort studies and nine publications on nine RCTs were included. All prospective cohort studies were in children or adolescents, and all RCTs were in adults. Prospective cohort studies on tooth erosion found no association between juice intake and tooth erosion, while those on dental caries incidence reported either no association or an inverse association between 100% fruit juice intakes and dental caries incidence. RCTs on tooth erosion showed decreased microhardness, increased surface enamel loss, increased erosion depth, greater enamel softening, and/or increased pellicle layer with 100% fruit juice, and those on dental caries showed increased demineralization of enamel slabs with 100% fruit juice.

Conclusions: The existing evidence on 100% fruit juice intake and caries and tooth erosion are not conclusive. Overall, prospective cohort studies in children and adolescents found no association between 100% fruit juice intake and tooth erosion or dental caries, but, RCT data in adults suggests that 100% fruit juice could contribute to tooth erosion and dental caries. The RCT data, however, were from small, short-term studies that utilized intra-oral devices generally devoid of normal plaque or saliva action, and generally employed conditions that are not reflective of normal juice consumption.

Flexural Properties and Elastic Modulus of Different Esthetic Restorative Materials: Evaluation after Exposure to Acidic Drink

Background

Acidic beverages, such as soft drinks, can produce erosion of resin composites. The purpose of the present study was to investigate mechanical properties of different esthetic restorative materials after exposure to acidic drink.

Methods

Nine different composites were tested: nanofilled (Filtek Supreme XTE, 3M ESPE), microfilled hybrid (G-ænial, GC Corporation), nanohybrid Ormocer (Admira Fusion, Voco), microfilled (Gradia Direct, GC Corporation), microfilled hybrid (Essentia, GC Corporation), nanoceramic (Ceram.X Universal, Dentsply De Trey), supranano spherical hybrid (Estelite Asteria, Tokuyama Dental Corporation), flowable microfilled hybrid (Gradia Direct Flo, GC Corporation), and bulk fill flowable (SureFil SDR flow, Dentsply De Trey). Thirty specimens of each esthetic restorative material were divided into 3 subgroups (n=10): specimens of subgroup 1 were used as control, specimens of subgroup 2 were immersed in 50 ml of Coca Cola for 1 week, and specimens of subgroup 3 were immersed in 50 ml of Coca Cola for 1 month. Flexural strength and elastic modulus were measured for each material with an Instron Universal Testing Machine. Data were submitted to statistical analysis.

Results

After distilled water immersion, nanofilled composite showed the highest value of both flexural strength and elastic modulus, but its flexural values decreased after acidic drink immersion. No significant differences were reported between distilled water and acidic drink immersion for all other materials tested both for flexural and for elastic modulus values.

Conclusions

Even if nanofilled composite showed highest results, acidic drink immersion significantly reduced flexural values.

Factores de riesgo de la atrición dental severa: un estudio de casos y controles

Objetivo: identificar los factores de riesgo de la atrición dental severa en pacientes que acudieron a instituciones de atención odontológica, públicas y privadas, de la ciudad de Cuenca, Ecuador. Materiales y métodos: fueron analizados 237 pacientes adultos, 79 casos con atrición dental grados 2, 3 y 4, según el índice de Smith y Knight, y 158 controles con atrición grados 0 y 1. Se realizó un examen clínico y fotográfico para determinar la relación entre la atrición dental y factores como edad, sexo, procedencia, número de dientes residuales, pH salival y bruxismo. Resultados: los pacientes mayores de 25 años (OR= 2,47 IC= 1,41 – 4,35 X2= 10,21 p= 0,001), con menos de 20 dientes en boca (OR= 4,95 IC= 1,47 – 16,62 X2= 7,97 p= 0,004) y con bruxismo (OR= 2,64 IC= 1,45 – 4,81 X2= 10,49 p= 0,001) tienen más probabilidades de presentar atrición dental severa. Luego de una regresión logística binaria se confirmó dicha relación: pacientes mayores de 25 años (OR= 2,03 IC= 1,08 – 3,818) con menos de 20 dientes en boca (OR= 3,90 IC= 1,07 – 14,19) y con bruxismo (OR= 3,22 IC= 1,70 – 6,10); sin embargo, se observó una capacidad predictora muy baja de la variables ajustadas según el R–cuadrado de Cox y Snell (0,123) y el R–cuadrado de Nagelkerke (0,172). Conclusiones: edad avanzada, menor cantidad de dientes en boca y bruxismo aumentaron la posibilidad de presentar atrición dental severa en los pacientes analizados. Mientras que el sexo masculino, la procedencia rural y el pH salival crítico (menor a 6) no se comportaron como factores de riesgo

In situ effect of Tooth Mousse containing CPP-ACP on human enamel subjected to in vivo acid attacks

OBJECTIVE

This in situ study aimed to evaluate the protective effect of Tooth Mousse (GC) containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on human enamel erosion and to compare the difference in erosion between the anteriorly and posteriorly positioned human enamel.

METHODS

This study used a 2-treatment (7 days each) crossover design with 12 healthy volunteers wearing intraoral appliances. Each appliance contained 4 human enamel specimens positioned on the buccal surfaces of the volunteers' maxillary central incisors and first molars. The specimens were intraorally treated withTooth Mousse (CPP-ACP group) or deionized water (control group) for 3 min and then exposed to in vivo acid attacks by rinsing with 150 ml of a cola drink (4 × 5 min/day). The surface microhardness (SMH) of the specimens was measured and used to calculate the percentage of SMH loss (%SMH_l). Erosion effect on enamel was also investigated by scanning electron microscopy (n = 4) at the end of study. The data were statistically analysed using two-way analysis of variance (ANOVA) and Tukey's test at a level of P < 0.05.

RESULTS

A significant decrease in %SMH_l was observed for the specimens of CPP-ACP group compared to that for the controls (P = 0.007). The specimens positioned posteriorly exhibited a significantly lower %SMH_l than those positioned anteriorly (P = 0.033). Samples of CPP-ACP group showed fewer etching patterns than those of the control group.

CONCLUSIONS

In this in situ model, application of Tooth Mousse containing CPP-ACP before erosion reduced the %SMH_l of human enamel. Enamel located in different positions showed different patterns of erosion.

CLINICAL SIGNIFICANCE

Application of Tooth Mousse containing CPP-ACP could be considered as a suitable preventive strategy against enamel erosion. ClinicalTrials.gov Identifier: NCT03426150.

Susceptibility of partially desalivated rats to erosive tooth wear by calcium-supplemented beverages

OBJECTIVES

To investigate the susceptibility of partially desalivated rats to erosive tooth wear (ETW); the anti-erosive effect of a calcium-supplemented beverage; and the quantification of ETW by microcomputed tomography (micro-CT).

METHODS

The study population consisted of thirty-eight rats, divided into partially desalivated (n = 19) and normal salivary flow (n = 19). They were randomly allocated into three subgroups (n = 6-7): A-diet soda, B-diet soda + calcium, C-water (control). Solutions were provided ad libitum for 28 days, and the rats were euthanized afterwards. Each left hemi-mandible was scanned using micro-CT for enamel volume (three molars) calculation. Visual analysis of photographs of the lingual surface of first molars was performed independently by three blinded examiners. Data were statistically analysed (α = .05).

RESULTS

Micro-CT revealed no significant differences between partially desalivated or normal groups. Rats consuming A had more enamel loss than those consuming B or C, which did not differ from each other. For visual analysis, desalivation did not affect ETW. Rats consuming C showed the lowest ETW, followed by B and then A, for both partially desalivated and normal rats. Spearman correlation between the two ETW quantification methods was -.65.

CONCLUSIONS

Partial desalivation did not increase ETW. Ca-containing beverage prevented ETW. Micro-CT quantified ETW, although it was not as sensitive as visual analysis.

Quantitative Swept-Source Optical Coherence Tomography of Early Enamel Erosion in vivo

Swept-source optical coherence tomography (SS-OCT) shows potential for the in vivo quantitative evaluation of micro-structural enamel surface phenomena occurring during early erosive demineralization. This randomized controlled single-blind cross-over clinical study aimed to evaluate the use of SS-OCT for detecting optical changes in the enamel of 30 healthy volunteers subjected to orange juice rinsing (erosive challenge) in comparison to mineral water rinsing (control), according to wiped and non-wiped enamel surface states. Participants were randomly allocated to 60 min of orange juice rinsing (pH 3.8) followed by 60 min of water rinsing (pH 6.7) and vice versa, with a 2-week wash-out period. In addition, the labial surfaces of the right or left maxillary incisors were wiped prior to SS-OCT imaging. An automated ImageJ algorithm was designed to analyse the back-scattered OCT signal intensity (D) after orange juice rinsing compared to after water rinsing. D was quantified as the OCT signal scattering from the 33 µm sub-surface enamel, normalised by the total OCT signal intensity entering the enamel. The back-scattered OCT signal intensity increased by 3.1% (95% CI 1.1-5.1%) in the wiped incisors and by 3.5% (95% CI 1.5-5.5%) in the unwiped incisors (p < 0.0001). Wiping reduced the back-scattered OCT signal intensity by 1.7% (95% CI -3.2 to -0.3%; p = 0.02) in comparison to the unwiped enamel surfaces for both rinsing solutions (p = 0.2). SS-OCT detected OCT signal changes in the superficial sub-surface enamel of maxillary central incisor teeth of healthy volunteers after orange juice rinsing.

Rinsing with antacid suspension reduces hydrochloric acid-induced erosion

OBJECTIVE

Mouthrinsing with antacids, following erosive episodes, have been suggested as a preventative strategy to minimize tooth surface loss due to their neutralizing effect. The purpose of this in situ study was to evaluate the effect of an antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate in controlling simulated erosion of enamel of intrinsic origin.

DESIGN

The experimental units were 48 slabs (3×3×2mm) of bovine enamel, randomly divided among 12 volunteers who wore palatal appliances with two enamel slabs. One of them was exposed extra-orally twice a day to 25mL of a hydrochloric acid (HCl) solution (0.01M, pH 2) for 2min. There were two independent phases, lasting 5 days each. In the first phase, according to a random scheme, half of the participants rinsed with 10mL of antacid suspension (Gaviscon(®), Reckitt Benckiser Healthcare Ltd.), while the remainder was rinsed with deionized water, for 1min. For the second phase, new slabs were inserted and participants switched to the treatment not received in the first stage. Therefore, the groups were as follows: (a) erosive challenge with HCl+antacid suspension; (b) erosive challenge with HCl+deionized water (DIW); (c) no erosive challenge+antacid suspension; (d) no erosive challenge+DIW. Specimens were assessed in terms of surface loss using optical profilometry and Knoop microhardness. The data were analyzed using repeated measures two-way analysis of variance and Tukey's tests.

RESULTS

Compared to DIW rinses, surface loss of enamel was significantly lower when using an antacid rinse following erosive challenges (p=0.015). The Knoop microhardness of the enamel was significantly higher when the antacid rinse was used (p=0.026).

CONCLUSIONS

The antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate, rinsed after erosive challenges of intrinsic origin, reduced enamel surface loss.

Supplementation of an orange juice with dietary proteins to prevent enamel and dentin erosion

Protein supplementation may be an alternative to reduce the erosive potential of acidic drinks. The aim of this in vitro study was to evaluate the erosive potential of an orange juice modified by dietary proteins. A commercially available orange juice was added 0.2 g/L casein, 2.0 g/L ovalbumin and their combination. The juice with no additives and a commercially available calcium-modified juice were used as negative and positive controls, respectively. Human enamel and dentin specimens (n=11) were tested in an erosion-remineralization cycling model. Enamel was analyzed by surface microhardness and profilometry, whilst dentin by profilometry only. Statistical analyses were performed using one-way ANOVA followed by Tukey's test (p<0.05). Calcium-modified juice showed the lowest erosive potential for both analyses (p<0.05). For enamel, the protein-added groups did not differ from each other (p>0.05) and showed significantly lower enamel loss compared to negative control (p<0.05). Regarding surface microhardness, casein showed the highest values compared to negative control (p<0.05). For dentin, none of the protein-added groups showed lower values of surface loss compared to negative control (p>0.05). In conclusion, for enamel the protein-modified orange juices presented reduced erosion of enamel, with casein showing a trend for better protection. For dentin, no reduction in the erosive potential was observed for the tested protein-modified orange juices.

In vitro effect of low-fluoride toothpastes containing sodium trimetaphosphate on enamel erosion

OBJECTIVE

To evaluate the effect of a low-fluoride dentifrice (LFD) containing sodium trimetaphosphate (TMP) on enamel erosion in vitro.

DESIGN

Bovine enamel blocks (n=144) were selected by surface hardness (SH) and subjected to erosive challenges, in two sets of experiments for 2 and 5 days. Blocks were randomly assigned to groups treated with slurries (5mL/block, for 15s) of following dentifrices: Placebo (no fluoride or TMP); LFD (250ppm F); LFD plus 0.25, 0.5, or 1.0% TMP; and a commercial positive control (1,425ppm F). The erosive challenge was produced by immersion in a soft drink (pH 2.8) for 5min, four times/day, interspersed by immersion in artificial saliva for 1h. SH and surface wear were analyzed as response variables. Data were submitted to 2-way ANOVA, followed by Student-Newman-Keuls test (p<0.05).

RESULTS

All groups treated with LFDs containing TMP had significantly lower enamel wear when compared with the other groups tested (p<0.001). Also, the LFDs containing TPM at lower concentrations promoted SH similar to the commercial positive control, both being significantly higher than the LFD without TMP and Placebo (p<0.001).

CONCLUSION

The supplementation of LFDs with TMP is able to significantly increase the anti-erosive potential of these formulations in vitro.

Dentifrice fluoride and abrasivity interplay on artificial caries lesions

Incipient caries lesions on smooth surfaces may be subjected to toothbrushing, potentially leading to remineralization and/or abrasive wear. The interplay of dentifrice abrasivity and fluoride on this process is largely unknown and was investigated on three artificially created lesions with different mineral content/distribution. 120 bovine enamel specimens were randomly allocated to 12 groups (n = 10), resulting from the association of (1) lesion type [methylcellulose acid gel (MeC); carboxymethylcellulose solution (CMC); hydroxyethylcellulose gel (HEC)], (2) slurry abrasive level [low (REA 4/ RDA 69); high (REA 7/RDA 208)], and (3) fluoride concentration [0/275 ppm (14.5 mM) F as NaF]. After lesion creation, specimens were brushed in an automated brushing machine with the test slurries (50 strokes 2×/day). Specimens were kept in artificial saliva in between brushings and overnight. Enamel surface loss (SL) was determined by optical profilometry after lesion creation, 1, 3 and 5 days. Two enamel sections (from baseline and post-brushing areas) were obtained and analyzed microradiographically. Data were analyzed by analysis of variance and Tukey's tests (α = 5%). Brushing with high-abrasive slurry caused more SL than brushing with low-abrasive slurry. For MeC and CMC lesions, fluoride had a protective effect on SL from day 3 on. Furthermore, for MeC and CMC, there was a significant mineral gain in the remaining lesions except when brushed with high-abrasive slurries and 0 ppm F. For HEC, a significant mineral gain took place when low-abrasive slurry was used with fluoride. The tested lesions responded differently to the toothbrushing procedures. Both slurry fluoride content and abrasivity directly impacted SL and mineral gain of enamel caries lesions.

A randomised in situ trial, measuring the anti-erosive properties of a stannous-containing sodium fluoride dentifrice compared with a sodium fluoride/potassium nitrate dentifrice

OBJECTIVES

To determine if a stabilised, stannous-containing sodium fluoride dentifrice provides greater enamel protection in situ against intraoral dietary erosive challenges compared with a sodium fluoride/potassium nitrate dentifrice.

METHODS

A single-centre, investigator blind, randomised, supervised, two-treatment, non-brushing, four-period crossover in situ study was undertaken, with each test period being 15 days. Thirty-five healthy adult subjects were recruited to participate in the study, which included four erosive acid challenges per day. Subjects were randomised to product treatment, which included either: (1) a stannous-containing sodium fluoride dentifrice (Oral-B(®) Pro-Expert Sensitive) or (2) a sodium fluoride/potassium nitrate dentifrice (Sensodyne(®) Pronamel(®) ). Each study subject wore an intraoral appliance retaining two sterilised, polished human enamel samples for 6 hours/day. Subjects swished with an allocated dentifrice slurry twice a day and with 250 ml of orange juice for 10 minutes (25 ml/minute over a 10-minute period) four times per day. The primary and secondary outcomes for this study were enamel loss measured using contact profilometry at days 15 and 5, respectively, using parametric analysis methods.

RESULTS

At day 15, a 38% lower enamel loss (P < 0.0001) was observed, with estimated medians of 2.03 μm (SE 0.247) and 3.30 μm (SE 0.379), in favour of the stannous-containing dentifrice. At day 5, specimens treated with the stannous-containing sodium fluoride dentifrice demonstrated 25% less enamel loss than those treated with the sodium fluoride/potassium nitrate dentifrice. Treatment differences at day 5 were also statistically significant (P < 0.05), with estimated medians of 1.37 μm (SE 0.177) and 1.83 μm (SE 0.223), respectively.

CONCLUSIONS

Results of this in situ study suggest the stabilised, stannous-containing sodium fluoride dentifrice could be used to provide significantly greater protection to enamel from erosive acid challenge compared with that provided by conventional fluoride-containing products.

Scaffold-free microtissues: differences from monolayer cultures and their potential in bone tissue engineering

OBJECTIVES

Cell-based therapies for bone augmentation after tooth loss and for the treatment of periodontal defects improve healing defects. Usually, osteogenic cells or stem cells are cultivated in 2D primary cultures, before they are combined with scaffold materials, even though this means a loss of the endogenous 3D microenvironment for the cells. Moreover, the use of single-cell suspensions for the inoculation of scaffolds or for the direct application into an area of interest has the disadvantages of low initial cell numbers and susceptibility to unwanted cellular distribution, respectively.

MATERIALS AND METHODS

We addressed the question whether an alternative to monolayer cultures, namely 3D microtissues, has the potential to improve osteogenic tissue engineering and its clinical outcome.

RESULTS

By contrast, to monolayer cultures, osteogenic differentiation of 3D microtissues is enhanced by mimicking in vivo conditions. It seems that the osteogenic differentiation in microtissues is enhanced by strong integrin-extracellular matrix interaction and by stronger autocrine BMP2 signaling. Moreover, microtissues are less prone to wash out by body fluids and allow the precise administration of large cell numbers.

CONCLUSION

Microtissue cultures have closer characteristics with cells in vivo and their enhanced osteogenic differentiation makes scaffold-free microtissues a promising concept in osteogenic tissue engineering.

CLINICAL RELEVANCE

Microtissues are particularly suitable for tissue engineering because they improve seeding efficiency of biomaterials by increasing the cell load of a scaffold. This results in accelerated osteogenic tissue formation and could contribute to earlier implant stability in mandibular bone augmentation.

In situ effect of dentifrices associated to CO2 laser in the permeability of eroded root dentin

OBJECTIVE

The aim of this study was to evaluate, through a crossover 2×2 in situ trial, the effect of a desensitizing dentifrice associated with CO2 laser irradiation to control the permeability of eroded root dentin.

BACKGROUND DATA

Facing the increased prevalence of erosive lesion and the need for preventive means to control painful symptoms related to them.

METHODS

Eighty slabs of bovine root dentin were subjected to initial erosive challenge (citric acid 0.3%, 2 h), followed by a remineralizing period in artificial saliva (24 h). Specimens were then divided according to dentin treatment: desensitizing dentifrice, desensitizing dentifrice+CO2 laser, fluoride anticavity dentifrice. and fluoride anticavity dentifrice+CO2 laser. After a 2-day lead-in period, 10 volunteers wore an intraoral palatal appliance containing four root dentin slabs, in two phases of 5 days each. During the intraoral phase, one side of the appliance was immersed in 0.3% citric acid, and the opposite side was immersed in deionized water, four times a day. One hour after the immersions, all specimens were brushed with dentifrice slurry provided by the researcher. After a 7-day washout period, volunteers were crossed over on the different dentifrice group. Each phase having been completed, the specimens were evaluated for permeability through an optical microscope.

RESULTS

Data were analyzed using ANOVA and no significant difference (p=0.272) was found between the surface treatments performed on bovine root dentin.

CONCLUSIONS

It can be concluded that fluoride anticavity or desensitizing dentifrice, regardless of the association with the CO2 laser irradiation, was able to control the permeability of eroded root dentin.

Scaffold-free microtissues: differences from monolayer cultures and their potential in bone tissue engineering

Objectives

The paper’s aim is to review dentin hypersensitivity (DHS), discussing pain mechanisms and aetiology.

Materials and methods

Literature was reviewed using search engines with MESH terms, DH pain mechanisms and aetiology (including abrasion, erosion and periodontal disease).

Results

The many hypotheses proposed for DHS attest to our lack of knowledge in understanding neurophysiologic mechanisms, the most widely accepted being the hydrodynamic theory. Dentin tubules must be patent from the oral environment to the pulp. Dentin exposure, usually at the cervical margin, is due to a variety of processes involving gingival recession or loss of enamel, predisposing factors being periodontal disease and treatment, limited alveolar bone, thin biotype, erosion and abrasion.

Conclusions

The current pain mechanism of DHS is thought to be the hydrodynamic theory. The initiation and progression of DHS are influenced by characteristics of the teeth and periodontium as well as the oral environment and external influences. Risk factors are numerous often acting synergistically and always influenced by individual susceptibility.

Clinical relevance

Whilst the pain mechanism of DHS is not well understood, clinicians need to be mindful of the aetiology and risk factors in order to manage patients’ pain and expectations and prevent further dentin exposure with subsequent sensitivity.

Efficacy of desensitizing dentifrices to occlude dentinal tubules

Dentine hypersensitivity occurs when patent dentinal tubules are subjected to external stimuli, with pain being reduced by products that occlude tubules. This study compared the efficacy of a recently developed arginine-containing dentifrice, two established strontium-based products, and a fluoride control to occlude tubules when subjected to acid challenge. Dentine specimens with patent tubules were divided into four groups that were treated with a slurry consisting of one of the pastes mixed with stimulated human saliva. Treated specimens were further subdivided and soaked in 0.3% citric acid for 10 s, 30 s, 2 min, 5 min or 10 min. Tubule occlusion on representative scanning electron microscopy images was scored by blind review. All three desensitizing pastes offered good tubule occlusion, which was maintained to varying degrees following acidic challenge. After immersion in acid for 10 and 30 s, the strontium acetate- and arginine-containing pastes almost fully occluded tubules, but only the strontium acetate paste retained this level of occlusion after immersion in acid for 2 min, with strong statistical evidence that this paste occluded more tubules than the other pastes after immersion in acid for 2 or 5 min. This suggests that strontium acetate pastes may be the most effective at reducing dentine hypersensitivity.

Effect of salivary factors on the susceptibility of hydroxyapatite to early erosion

OBJECTIVE

Salivary pellicle is known to reduce the erosion of enamel and differences in the level of protection exist between individual saliva sources, but which parameters or components are important is not known. The focus of this study was to investigate the relationship between saliva parameters and early erosion of hydroxyapatite (HAp) with an in situ grown saliva film.

METHODS

Twenty-eight volunteers carried two HAp and one porcelain discs in their buccal sulcus for 1.5 h. Next, the discs covered with pellicle and the attached saliva film were exposed extraorally to 50 mM (pH = 3) citric acid for 2 min and unstimulated and stimulated saliva was collected. Calcium loss from HAp after erosive challenge was measured, corrected for calcium loss from pellicle on porcelain discs and averaged. Several salivary parameters were analysed. Pearson's linear correlation and multiple regression analysis were used to study the relation between saliva parameters and HAp erosion.

RESULTS

Significant correlations were found between HAp erosion and the concentration of phosphorus in unstimulated saliva (r = 0.40, p = 0.03) and between HAp erosion and the concentration of sodium (r = -0.40, p = 0.03), chloride (r = -0.47, p = 0.01), phosphorus (r = 0.45, p = 0.01) and flow (r = -0.39, p = 0.04) of stimulated saliva. Multivariate analysis revealed a significant role in the HAp erosion for sodium, urea, total protein, albumin, pH and flow of unstimulated saliva and for sodium, potassium, urea, and phosphorus of stimulated saliva.

CONCLUSIONS

Several salivary parameters are associated with the susceptibility of HAp to erosion.

Dental erosion: understanding this pervasive condition

Dental erosion is a contemporary disease, mostly because of the change of the eating patterns that currently exist in society. It is a "silent" and multifactorial disease, and is highly influenced by habits and lifestyles. The prevalence of dental erosion has considerably increased, with this condition currently standing as a great challenge for the clinician, regarding the diagnosis, identification of the etiological factors, prevention, and execution of an adequate treatment. This article presents a dental erosion review and a case report of a restorative treatment of dental erosion lesions using a combination of bonded ceramic overlays to reestablish vertical dimension and composite resin to restore the worn palatal and incisal surfaces of the anterior upper teeth. Adequate function and esthetics can be achieved with this approach.

Erosive lesions in patients with alcoholism

BACKGROUND

The authors conducted a study to determine the occurrence of erosive tooth lesions in patients with alcoholism and to establish the influence of salivary flow rates and pH levels on their appearance.

METHODS

The authors conducted a cross-sectional study in 140 participants (70 with clinically diagnosed alcoholism who were undergoing therapy for their addiction were in the test group and 70 who did not consume alcohol were in the control group). The authors determined the participants' salivary statuses by measuring the flow rates and pH levels of both unstimulated and stimulated saliva.

RESULTS

The authors found more erosive lesions in the test group (P < .01). They detected a higher number of erosive lesions in participants in the test group who had a pH range of 5 to 6 compared with a pH range of 6 to 7 (P = .01). They found a significant correlation between alcoholism and unstimulated salivary flow rate (P < .05).

CONCLUSIONS

The salivary flow rate was similar in control and test groups. The prevalence of erosion in the test group was higher than that in the control group, which may be related to the decrease in salivary pH of both stimulated and unstimulated saliva in this group. The results of the study showed no connection between erosion prevalence and pH levels and stimulated salivary flow rates.

CLINICAL IMPLICATIONS

Patients with alcoholism may be at risk of developing erosive lesions on their teeth owing to the low pH level of their oral environment and decreased saliva levels.

Development of an orange juice surrogate for the study of dental erosion

The aim of this study was to create a synthetic juice (SJ) to be used as a surrogate for natural orange juices in erosion studies, verifying its erosive potential. The SJ was formulated based on the chemical composition of orange juices from different locations. Forty enamel and 40 root dentin specimens were randomly assigned into 4 experimental groups (n=10): SJ; 1% Citric Acid (CA); Minute Maid Original® (MM) and Florida Natural Original® (FN). The specimens were immersed in their respective solutions for 5 min, 6x/day for 5 days, in an erosion-remineralization cycling model. Enamel specimens were analyzed by surface Knoop microhardness and optical profilometry and dentin specimens only by optical profilometry. Outcomes were analyzed statistically by ANOVA followed by Tukey’s test considering a significance level of 5%. For enamel, the surface loss and microhardness changes found for MM and SJ groups were similar (p>0.05) and significantly lower (p<0.01) than those found in the CA group. For dentin, CA promoted significantly greater (p<0.01) surface loss compared with all the other groups. No significant difference (p>0.05) was observed in dentin surface loss between MM and SJ. In conclusion, CA was the most erosive solution, and SJ had a similar erosive potential to that of MM natural orange juice.

Sodium bicarbonate solution as an anti-erosive agent against simulated endogenous erosion

This study investigated whether sodium bicarbonate solution, applied on enamel previously exposed to a simulated intrinsic acid, can control dental erosion. Volunteers wore palatal devices containing enamel slabs, which were exposed twice daily extra-orally to hydrochloric acid (0.01 M, pH 2) for 2 min. Immediately afterwards, the palatal devices were re-inserted in the mouth and volunteers rinsed their oral cavity with a sodium bicarbonate solution or deionized water for 60 s. After the washout period, the palatal devices were refilled with a new set of specimens and participants were crossed over to receive the alternate rinse solution. The surface loss and surface microhardness (SMH) of specimens were assessed. The surface loss of eroded enamel rinsed with a sodium bicarbonate solution was significantly lower than the surface loss of eroded enamel rinsed with deionized water. There were no differences between treatments with sodium bicarbonate and deionized water for SMH measurements. Regardless of the solution used as an oral rinse, eroded enamel showed lower SMH than uneroded specimens. Rinsing with a sodium bicarbonate solution after simulated endogenous erosive challenge controlled enamel surface loss but did not alter the microhardness.

Synthesis of nanobioglass and formation of apatite rods to occlude exposed dentine tubules and eliminate hypersensitivity

The occlusion of patent dentine tubules may reduce or eliminate hypersensitivity by restricting dentinal fluid movement. The efficacy of a novel sol-gel nanobioglass and a melt-derived bioglass to occlude tubules and promote apatite formation was tested by mechanically brushing a slurry of bioglass powder and human saliva onto dentine possessing exposed tubules. Scanning electron microscopy, focused ion beam and energy-dispersive X-ray spectroscopy were used to characterize the powders and assess tubule occlusion. Melt-derived bioglass possessed an irregular particle morphology and had a mean size of 3.30 +/- 0.42 microm. The sol-gel bioglass particles were spherical, with a mean size of 0.65 +/- 0.19 microm. Dentine treated with melt-derived bioglass exhibited a tightly adherent continuous apatite layer. Treatment with nanobioglass resulted in particle deposition within tubules and formation of apatite rods which were tightly adherent to tubule walls and continuous to a measured depth of 270 microm.

Clinical in situ study investigating abrasive effects of two commercially available toothpastes

The aim of this study was to determine if the abrasive effect on dentine of two commercially available toothpastes, known to vary in their in vitro abrasive levels, can be differentiated in an in situ model after 10 days, assessed by contact profilometry. This was a single centre, single blind, randomized, split mouth, two treatment, in situ study, in 34 healthy subjects, evaluating the abrasive effects of two marketed desensitizing toothpastes, (Colgate Sensitive Multi Protection toothpaste - C; Sensodyne Total Protection - S). Subjects wore bi-lateral, lower buccal appliances, each fitted with four dentine sections which were power brushed three times a day with the treatment regimen. Each subject received two toothpaste treatments for 10 days during the treatment period. Samples were measured at baseline and day 10 by contact and non-contact profilometry and day 5 by contact profilometry. Thirty-four subjects were included in the efficacy analysis. Results from contact profilometry showed statistically significant (P < 0.0001) dentine loss compared to baseline at day 5 and 10 for both pastes. At each time point, C showed statistically significantly greater dentine loss than S, P < 0.0001. After 10 days treatment, the difference in dentine loss between the pastes was 1.4 microm. The non-contact profilometry data showed similar trends. After 10 days of treatment, C showed statistically significantly greater dentine loss than S, with treatment difference of 0.9 microm, P = 0.0057. The methodology used has successfully differentiated between the abrasivity of the two pastes in respect of dentine surface loss over time in an in situ environment.