Characterization of sound enamel and natural white spot lesions / Caracterização de esmalte hígido e lesões de mancha branca naturais

Objective: To compare optical, morphological, chemical, and physical aspects of the sound enamel and white spot lesions (WSL) classified as ICDAS 2. Material and Methods: Seventeen human molars with one surface presenting WSL and a sound surface (2 x 2 mm window) were characterized by Quantitative light-induced fluorescence (QLF ®), Optical coherence tomography (OCT), microhardness, and Raman spectroscopy. The ANOVA and Tukey's test were used at 5% significance level. Results: The QLF comparison between distinct substrates yielded decreased ∆Q (integrated fluorescence loss) of -15,37%mm2 and -11,68% ∆F (fluorescence loss) for WSL. The OCT detected mean lesion depth of 174,43 µm. ANOVA could not detect differences in the optical attenuation coefficient between the substrates (p>0.05). Lower microhardness measures were observed in WSL than on sound enamel (p<0.05). The Raman spectra showed four vibrational phosphate bands (v1, v2, v3, v4), where the highest peak was at 960.3 cm-1(v1) for both substrates. However, a 40% decrease in phosphate (v1) was detected in WSL. The peak at 1071 cm-1 was higher for sound enamel, indicating the presence of a phosphate band instead of the B-type carbonate. The spectra showed higher intensity of the organic composition at 1295 cm-1 and 1450 cm -1 for WSL. Conclusion: Non-invasive QLF, OCT and Raman spectroscopy were able to distinguish differences in fluorescence, optical properties, and organic/inorganic components, respectively, between sound enamel and WSL, validated by the destructive microhardness analysis. (AU)

Objetivo: Comparar os aspectos ópticos, morfológicos, químicos e físicos do esmalte sadio e das lesões de mancha branca naturais, classificada como ICDAS 2. Material e métodos: Dezessete molares humanos com uma face apresentando uma lesão de mancha branca natural e outra face o esmalte hígido (2 x 2 mm) foram caracterizados utilizando a Fluorescência quantitativa induzida pela luz (QLF ®), Tomografia de coerência óptica (OCT), Microdureza e Espectroscopia Raman. A ANOVA e o teste de Tukey foram utilizados ao nível de significância de 5%. Resultados: A comparação entre os substratos distintos, utilizando o QLF ® demonstrou uma diminuição no ∆Q (perda de fluorescência integrada) de -15,37%mm2 e -11,68% de ∆F (Perda de fluorescência) para a lesão de mancha branca. O OCT detectou uma profundidade média de lesão de 174,43µm. A ANOVA não detectou diferenças no coeficiente de atenuação óptica entre os substratos (>0,05). Microdureza significantemente menor foi detectada nas lesões de mancha branca do que no esmalte sadio (p<0,05). Os espectros Raman mostraram quatro bandas vibracionais do fosfato (v1,v2,v3,v4), onde o maior pico foi em 960,3cm-1para ambos os substratos. No entanto, uma diminuição de 40% no fosfato (v1) foi detectada na lesão. O pico em 1071cm-1foi maior para o esmalte hígido, demonstrando tratar-se da banda do fosfato, ao invés do carbonato tipo B. Os espectros apresentaram maior intensidade da composição orgânica em 1295cm-1e 1450 cm-1para a lesão de mancha branca. Conclusão:Os métodos não invasivos QLF, OCT e espectroscopia Raman foram capazes dediferenciar a fluorescência, propriedades ópticas e conteúdo orgânico/inorgânico do esmalte sadio comparado com esmalte com lesões de mancha branca, sendo validado pela análise de microdureza. (AU)

Hydroxy acids for adhesion to enamel and dentin: Long-term bonding performance and effect on dentin biostability.

OBJECTIVES: To test the demineralization potential, bonding performance, and dentin biostability when using hydroxy acids for etching enamel and dentin. METHODS: Surface microhardness, roughness and depth of demineralization were investigated after etching enamel and dentin with 35 % glycolic acid (Gly), tartaric acid (Ta), gluconic acid (Glu), gluconolactone (Gln), or phosphoric acid (Pa) (n = 5/group). Dentin microtensile bond strength (µTBS) after 24 h or 1 year of bonding (n = 8 teeth/group) and enamel shear bond strength (SBS) after 24 h (n = 10 teeth/group) were obtained. In dentin, failure mode was classified as adhesive, cohesive in dentin/resin, or mixed. Dentin biostability was assessed by loss of dry weight and collagen degradation after 30-day incubation (n = 10 beams/group). Statistical analysis consisted of ANOVA with post-hoc Tukey's HSD, Tukey-Kramer test, Bonferroni correction, and Fisher's exact tests (α = 0.05). RESULTS: Gly showed better or similar results than Pa for enamel microhardness and dentin roughness, while no significant differences were observed among Ta, Glu, and Gln (p > .05). Hydroxy acids produced significantly shallower demineralization than Pa (p < .05). Gln resulted in the lowest SBS and µTBS, while Gly, Glu, Ta, and Pa showed no significant difference. There was no significant difference in µTBS between 24 h and 1 year of storage. The association between failure mode and etchant was statistically significant after 24 h only (p < .001). Hydroxy acids resulted in higher dentin biostability than Pa (p < .05). CONCLUSIONS: Gly, Glu and Ta resulted in adequate bonding performance and reduced dentin degradation and are potential alternative etchants to improve long-term stability of adhesive restorations. CLINICAL SIGNIFICANCE: This study supports the potential use of hydroxy acids as alternative etchants when bonding to enamel and dentin and demonstrates that specific acids are more suitable to be used in adhesion since they result in appropriate bond strength and less dentin degradation.

Profile of a 10-MDP-based universal adhesive system associated with chlorhexidine: Dentin bond strength and in situ zymography performance.

The incorporation of functional monomers and proteolytic inhibitors into adhesive systems have shown to be promising strategies to improve the longevity of adhesive restorations. The aim of this study was to evaluate the long-term bonding performance and anti-gelatinolytic effect of a 10-MDP-based universal adhesive system applied in combination with 2% chlorhexidine digluconate (CHX). For that, this study assessed the resin-dentin bond strength and the in situ gelatinolytic activity profile at the adhesive interface at initial and after 6 month of storage. One hundred and two sound human third molars were prepared and randomly divided into 3 groups according to the adhesive strategy: SB (two-step etch-and-rinse adhesive, Adper Single Bond 2, 10-MDP-free control group); SU-ER (Adper Single Bond Universal, 10-MDP containing universal adhesive applied on etch-and-rinse mode); and SU-SE (SU applied on self-etching mode). The groups were subdivided into two according to the dentin pretreatment: W - water or CHX- 2% chlorhexidine digluconate aqueous solution (SB-W; SB-CHX; SU-ER-W; SU-ER-CHX; SU-SE-W; SU-SE-CHX) and subsequently restored according to the manufacturer's instructions. Bond strength (n = 12) was assessed by a microtensile test (µTBS) (500N/0.5 mm/min) after 24h or after 6 months of storage. In situ zymography was performed to evaluate anti-gelatinolytic activity (n = 5). Resin-dentin samples were incubated with fluorescein-conjugated gelatin for 24 h at 37 °C and analyzed by confocal laser scanning microscopy. Fluorescence indicating gelatinolytic activity at hybrid layer zone and adjacencies was quantified using Image J. Data was analyzed by three-way ANOVA and Tukey post-hoc tests (p < 0.05). Results: SU-SE showed the highest bond strength values, while similar results were observed for SU-ER and SB. No statistical significant differences were observed between pretreatment (CHX vs. W) or storage time (initial vs. 6 months of aging). For in situ zymography, fluorescence was detected in all groups and CHX pre-treatment was able to inhibit the gelatinolytic activity in all conditions. The 10-MDP-based universal adhesive system in self-etching mode was the strategy that showed the best bonding performance irrespective of its combination with chlorhexidine. Pre-treatment with CHX did not impair the bond strength when used in combination with 10-MDP and it may promote collagen stability overtime.

Application of BMP-2/FGF-2 gene-activated scaffolds for dental pulp capping.

OBJECTIVES: To evaluate the effect of non-viral gene therapy on human dental pulp stem cells (DPSCs) in an in vitro and an ex vivo model. MATERIALS AND METHODS: Nanoplexes comprising polyethyleneimine (PEI) and plasmid DNA (pDNA) encoding for fibroblast growth factor-2 (pFGF-2) and bone morphogenic protein-2 (pBMP-2) were cultured with DPSCs to evaluate cytotoxicity, protein expression, and mineralization activity. Collagen scaffolds loaded with these nanoplexes or mineral trioxide aggregate (MTA) were utilized in an ex vivo tooth culture model to assess pulp response, over a period of 14 days. All nanoplex formulations were characterized for size and zeta potential by measuring dynamic light scattering and electrophoretic mobility, respectively. RESULTS: DPSCs treated with the nanoplexes showed increased cell proliferation and enhanced expression of BMP-2 and FGF-2 proteins. Collagen scaffolds containing PEI-pBMP-2 and/or pFGF-2 nanoplexes significantly increased cell proliferation, BMP-2 and FGF-2 expression, and mineralization when compared to MTA. Ex vivo histology showed a well-preserved pulp and healthy tissue in both the MTA and scaffold groups. Connective tissue in contact with the scaffold was dense and homogeneous, with some cells present in contact and within the scaffold. CONCLUSION: Transfection of DPSCs with pBMP-2/pFGF-2 nanoplexes resulted in increased expression of BMP-2 and FGF-2, enhanced proliferation, and mineralization properties compared to MTA. These findings were supported by the ex vivo observations. CLINICAL RELEVANCE: This biological approach in pulp capping brings new insights into the effective management of engineered pulp tissues, mainly those generated by the transplantation of DPSCs in empty root canals.

Antibacterial Efficacy of Synthetic and Natural-Derived Novel Endodontic Irrigant Solutions.

The aim of this study was to compare the efficacy of grape seed extract (GSE), calcium hypochlorite [Ca(ClO)2], and sodium hypochlorite (NaOCl) irrigant solutions with rotary or reciprocating instrumentation for disinfection of root canals inoculated with Enterococcus faecalis. The mesiobuccal root canals of mandibular molars were prepared and inoculated with Enterococcus faecalis for 21 days. The roots were then randomly divided into the following eight experimental groups (n=11) according to the instrumentation technique and disinfection protocol: ProTaper Next or Reciproc R25 with sodium chloride (control group), 6% NaOCl, 6% Ca(ClO)2, or 50% GSE used for irrigation during instrumentation. The antimicrobial activity was determined on the basis of a reduction in colony-forming units (CFUs) counted on bacterial samples collected before and after root canal instrumentation and expressed as a percentage of reduction. Data were evaluated by two-way ANOVA followed by Tukey HSD post-hoc tests (p<0.05). No significant differences were observed in bacterial reduction between the ProTaper Next and Reciproc R25 systems (p>0.05), regardless of the irrigant solution used. Furthermore, all active solutions (6% NaOCl, 50% GSE, and 6% Ca(ClO)2) showed similar potential to reduce bacterial counts (p>0.05) and were significantly more effective than sodium chloride (control) (p<0.05). The results suggest that the GSE and Ca(ClO)2 have potential clinical application as irrigant solutions in endodontic therapy since they present bactericidal efficacy against Enterococcus faecalis.

Antibacterial efficacy of synthetic and natural-derived novel endodontic irrigant solutions

Abstract The aim of this study was to compare the efficacy of grape seed extract (GSE), calcium hypochlorite [Ca(ClO)2], and sodium hypochlorite (NaOCl) irrigant solutions with rotary or reciprocating instrumentation for disinfection of root canals inoculated with Enterococcus faecalis. The mesiobuccal root canals of mandibular molars were prepared and inoculated with Enterococcus faecalis for 21 days. The roots were then randomly divided into the following eight experimental groups (n=11) according to the instrumentation technique and disinfection protocol: ProTaper Next or Reciproc R25 with sodium chloride (control group), 6% NaOCl, 6% Ca(ClO)2, or 50% GSE used for irrigation during instrumentation. The antimicrobial activity was determined on the basis of a reduction in colony-forming units (CFUs) counted on bacterial samples collected before and after root canal instrumentation and expressed as a percentage of reduction. Data were evaluated by two-way ANOVA followed by Tukey HSD post-hoc tests (p<0.05). No significant differences were observed in bacterial reduction between the ProTaper Next and Reciproc R25 systems (p>0.05), regardless of the irrigant solution used. Furthermore, all active solutions (6% NaOCl, 50% GSE, and 6% Ca(ClO)2) showed similar potential to reduce bacterial counts (p>0.05) and were significantly more effective than sodium chloride (control) (p<0.05). The results suggest that the GSE and Ca(ClO)2 have potential clinical application as irrigant solutions in endodontic therapy since they present bactericidal efficacy against Enterococcus faecalis.

Resumo O objetivo deste estudo foi comparar a eficácia do extrato de semente de uva (ESU), hipoclorito de cálcio [Ca(ClO)2] e hipoclorito de sódio (NaOCl) como soluções irrigadores quando utilizadas com instrumentos reciprocantes e rotatórios para desinfecção de canais radiculares infectados com Enterococcus faecalis. Raízes mesio-vestibulares de molares inferiores foram preparados e inoculados com E. faecalis por 21 dias. As raízes foram aleatoriamente divididas em 8 grupos (n=11) de acordo com a técnica de instrumentação e protocolo de irrigação: ProTaper Next ou Reciproc R25 associados com soro fisiológico (grupo controle), Ca(ClO)2 6%, NaOCl 6% ou ESU 50%. A atividade antimicrobiana foi determinada pela redução do número de Unidades Formadoras de Colonias (UFCs) coletadas antes e após a instrumentação e expressas em porcentagens de redução. Os dados foram analisados estatisticamente pelos testes ANOVA seguido pelo teste complementar de Tukey HSD (p<0,05). Não foi encontrado diferença estatisticamente significante na redução bacteriana entre os sistemas ProTaper Next e Reciproc R25 (p>0.05), independente da solução irrigadora usada. Além disso, todas as soluções ativas (NaOCl, ESU e Ca(ClO)2) mostraram similar potencial em reduzir a quantidade de bactérias (p>0.05) e foram significativamente mais efetivas que o soro fisiológico (p<0.05). Pode-se concluir que o ESU e o Ca(ClO)2 apresentam potencial para aplicação clínica como irrigantes endodônticos uma vez que apresentaram efetividade antimicrobiana contra o E. faecalis.

Sodium Trimetaphosphate as a Novel Strategy for Matrix Metalloproteinase Inhibition and Dentin Remineralization.

The effect of sodium trimetaphosphate (STMP) as an antiproteolytic and remineralizing agent on demineralized dentin was evaluated in vitro. The inhibitory potential of STMP at 0.5, 1.5, 3.5, and 5% against recombinant matrix metalloproteinases (MMPs) MMPs-2 and -9 was assessed by zymography. To investigate its remineralization potential, 40 bovine root specimens were obtained and subjected to a demineralization protocol to produce caries-like dentin lesions. After that, dentin surfaces were divided into 3 areas: (1) mineralized (no treatment); (2) demineralized; and (3) demineralized/treated with STMP and submitted to a pH-cycling associated or not with STMP (1.5, 3.5, or 5% STMP, 10 min of treatment). After that, superficial hardness (SH) and cross-sectional hardness (CSH) were determined. Polarized light microscopy (PLM) was used to qualitatively evaluate mineralization within the caries-like lesions. The zymographic analysis showed that STMP solution is a potent inhibitor of the gelatinolytic activity of MMPs-2 and -9 depending on the dose, since the lowest concentration (0.5%) partially inhibited the enzyme activity, while the higher concentrations completely inhibited enzyme activity. Regarding remineralization effect, only 1.5% STMP solution enhanced both the SH and CSH. PLM showed that the area treated with 1.5% STMP presented similar birefringence as mineralized sound dentin. In conclusion, 1.5% STMP solution is effective as an antiproteolytic agent against MMPs and promotes dentin remineralization.

Effect of chemical and natural irrigant solutions on microhardness of root dentin­ an in vitro study

Aim: Modifications in the mechanical properties of dentin may reduce the fracture resistance of tooth, especially after endodontic treatment. The aim of present study was to evaluate the effect of the irrigation with different root canal irrigants on the microhardness of root dentin. Methods: The coronal portion of 60 single-rooted bovine incisors was sectioned and the pulpal tissue removed using endodontic K-files. The roots were cut transversely to obtain 2 fragments, which were embedded in acrylic resin and randomly distributed into six groups (n=20) according to the irrigation protocol: distilled water (DW) (control); 2% chlorhexidine solution (CHX); 6% sodium hypochlorite (NaOCl); 6% calcium hypochlorite (Ca[OCl]2); QMix; and 6.5% grape seed extract solution (GSE). The solutions were kept in contact with the root dentin specimens for 30 min. After that, irrigation with 5 mL of DW was performed. The Vickers microhardness was determined by performing three indentations in all specimens, using 300-g load and 20-second dwell time. The first indentation was made 1.000 µm from the root canal entrance, and two other indentations were made at a distance of 200 µm from each other. The microhardness value for each specimen was obtained as the average of the results for the three indentations. Data were statistically analyzed using one-way ANOVA with 5% significance level. Results: All the tested irrigant solutions maintained the same microhardness level of the root dentin when compared to the control group, with no statistically significant differences between them (p<0.05) Conclusion: The tested irrigant solutions did not present ability to modify the microhardness of root dentin

Effect of synthetic and natural-derived novel endodontic irrigant solutions on mechanical properties of human dentin.

This study aimed to evaluate the effects of different synthetic and natural-derived root canal irrigants (6% sodium hypochlorite [NaOCl], 6% calcium hypochlorite [Ca(OCl)2] and 6.5% grape seed extract [GSE]) on dentin mechanical properties (flexural strength, ultimate tensile strength [UTS] and fracture resistance). Rectangular-shaped beams and hourglass-shaped sections obtained from mid-coronal and root dentin were treated with 6% NaOCl, 6% Ca(OCl)2 or 6.5% GSE for 30 min. The irrigant solutions were replaced every 5 min. Then, the dentin specimens were rinsed with distilled water (DW) followed by incubation with 17% EDTA for 1 min, and thoroughly rinsed with DW again. Specimens from the control group were tested without prior irrigation. After treatment with the irrigants, dentin beams were used to assess the flexural strength (n = 10) while UTS was evaluated using the root dentin hourglass-shaped sections (n = 10). Similarly, roots with 1 mm of dentinal wall thickness were obtained from human teeth and treated with the same irrigant solutions (n = 10). A compressive loading was applied to the coronal surfaces of roots until fracture. The values of each mechanical test were statistically analyzed individually by one-way ANOVA followed by Tukey HSD test (P < 0.05). NaOCl significantly reduced the mechanical properties of dentin in all mechanical tests (P < 0.05) and no statistical difference was found among Ca(OCl)2, GSE and control group (P > 0.05). It can be concluded that Ca(OCl)2 and GSE may be alternative irrigant solutions, since they do not negatively affect the dentin mechanical properties.

Co-distribution of cysteine cathepsins and matrix metalloproteases in human dentin.

It has been hypothesized that cysteine cathepsins (CTs) along with matrix metalloproteases (MMPs) may work in conjunction in the proteolysis of mature dentin matrix. The aim of this study was to verify simultaneously the distribution and presence of cathepsins B (CT-B) and K (CT-K) in partially demineralized dentin; and further to evaluate the activity of CTs and MMPs in the same tissue. The distribution of CT-B and CT-K in sound human dentin was assessed by immunohistochemistry. A double-immunolabeling technique was used to identify, at once, the occurrence of those enzymes in dentin. Activities of CTs and MMPs in dentin extracts were evaluated spectrofluorometrically. In addition, in situ gelatinolytic activity of dentin was assayed by zymography. The results revealed the distribution of CT-B and CT-K along the dentin organic matrix and also indicated co-occurrence of MMPs and CTs in that tissue. The enzyme kinetics studies showed proteolytic activity in dentin extracts for both classes of proteases. Furthermore, it was observed that, at least for sound human dentin matrices, the activity of MMPs seems to be predominant over the CTs one.

Bond Strength between Fiber Posts and Root Dentin Treated with Natural Cross-linkers.

INTRODUCTION: The aim of this study was to investigate the effects of a proanthocyanidin-rich extract (grape seed extract [GSE]) on the bond strength and stability of the adhesion of fiber posts to the root dentine using 2 adhesive systems: a total-etch and a self-etch adhesive system. METHODS: Single-rooted human teeth were randomly divided into 6 groups: G1 (control), untreated + total-etch adhesive Adper Scotchbond Multi-Purpose (3M ESPE, St Paul, MN); G2, 6.5% GSE for 5 minutes + SB; G3, 10% GSE for 5 minutes + SB; and G4 to G6 groups were similar to previous ones; however, the self-etch adhesive system Clearfil SE Bond (Kuraray, Kurashiki, Japan) was used. Fiber posts were cemented with RelyX ARC (3M ESPE), and the specimens were immediately tested for push out or stored for 12 months. The bond strength means were analyzed by analysis of variance and Games-Howell post hoc tests (α = 0.05). Additionally, matrix metalloproteinase inhibition by 0.65%, 0.065%, and 0.0065% GSE was examined with gelatin zymography. RESULTS: The use of GSE did not affect immediate bond strength to dentin and contributed to preserve the bond strength after 12 months (P < .05) for both adhesives. The bond strength of SB was significantly higher than Clearfil SE Bond (P < .05). Gelatin zymography showed reduced matrix metalloproteinase activity when recombinant enzymes were incubated with both 0.65% and 0.065% GSE, with complete inhibition at the highest concentration. CONCLUSIONS: The pretreatment with GSE can be used as a natural alternative to improve bond strength stability of dentin-adhesive interfaces in root canals.

Influence of chlorhexidine application time on the bond strength between fiber posts and dentin.

INTRODUCTION: The aim of this study was to investigate the effects of chlorhexidine (CHX) application time on the bond strength and durability of the adhesion of fiber posts relined with resin composite to the root dentin. METHODS: Eighty bovine incisor roots were divided into 4 groups after root preparation: control group (irrigation with physiological solution) and experimental groups, CHX for 30 seconds, CHX for 60 seconds, and CHX for 120 seconds. Fiber posts relined with resin composite were cemented with RelyX ARC. The Scotchbond Multi-Purpose total-etching adhesive system was used in half of the samples of each group, and the Clearfil SE Bond self-etching adhesive system was used in the other half. The samples were randomly divided into 2 subgroups, 24 hours of storage and 12 months of storage. All roots were sectioned transversely, and push-out tests were performed. Bond strength means were analyzed by analysis of variance and Tukey test (α = 0.05). Failure mode was determined by examining specimen's surfaces under scanning electron microscope, and its distribution was evaluated by using χ(2) test (α = 0.05). RESULTS: CHX pretreatment resulted in homogeneous bond strength values at 24 hours and 12 months of storage, irrespective of the CHX application time and adhesive system (P < .05). A significant bond strength decrease was noticed after 12 months of storage when irrigation was performed with physiological solution in the control groups (P > .05). Significant differences were observed for fracture patterns (P < .001). CONCLUSIONS: The use of CHX pretreatment could preserve the bond strength of the fiber post relined with resin composite to root dentin for 12 months, irrespective of the CHX application time and adhesive system used.

Changes in the stiffness of demineralized dentin following application of tooth whitening agents.

OBJECTIVE: The purpose of this study was to evaluate the effect of the bleaching agents on the elastic modulus of bovine demineralized dentin matrix (EMDM). MATERIALS AND METHODS: Eighty-five slices were obtained from 17 bovine teeth. The slices were divided randomly into five experimental groups (n = 17): unbleached control group (CG), 4% hydrogen peroxide (HP4), 4% hydrogen peroxide + 0.05% Ca (HP4 + Ca), 7.5% hydrogen peroxide + ACP (HP7.5) and 10% carbamide peroxide (CP10). The HP4, HP4 + Ca and CP10 groups were treated with the bleaching agents for 8 h/day (14 days), while the samples of HP7.5 group were exposed to bleaching agent for 30 min twice a day (14 days). The CG was kept in 100% humidity. After bleaching treatments, the enamel of the samples was removed and 85 dentin beams (0.5 × 1.7 × 7.0 mm) were prepared. Afterwards, the beams were immersed in 10% phosphoric acid solution (5 h) and rinsed with water (10 min). The beams were tested after 24 h, 7 and 14 days of storage in distilled water, using three-point bend method. Data were statistically analyzed using ANOVA and Fisher's test. RESULTS: All bleaching treatments reduced the EMDM. After 14 days post-bleaching, the EMDM increased for HP4 and HP4+Ca groups. CONCLUSIONS: The use of bleaching agents promoted a decrease in EMDM, which indicates that the bleaching treatment interacts with the dentin organic matrix. The EMDM measurement for the specimens of the 7.5% hydrogen peroxide group that were immersed in water at 14 days post-bleaching did not recover the EMDM values when compared to the control group.

Direct restorative treatment of dental erosion caused by gastroesophageal reflux disease associated with bruxism: a case report.

Gastroesophageal reflux disease (GERD) is a gastrointestinal disorder in which stomach acids are chronically regurgitated into the esophagus and oral cavity. Continual exposure of the teeth to these acids can cause severe tooth wear. Dentists are often the first healthcare professionals to diagnose dental erosion in patients with GERD. This article presents a case report of a 27-year-old male smoker with tooth wear and dentin sensitivity caused by GERD associated with bruxism. After diagnosis, a multidisciplinary treatment plan was established. The initial treatment approach consisted of medical follow-up with counseling on dietary and smoking habits, as well as management of the gastric disorders with medication. GERD management and the dental treatment performed for the eroded dentition are described, including diagnosis, treatment planning, and restorative therapy.

Efeito de diferentes técnicas restauradoras na nanoinfiltração e na resistência adesiva de restaurações classe II / Effect of different restorative techniques on nanoleakage and bond strength of class II restorations

A formação de uma interface de união efetiva entre dente e material restaurador é um dos fatores determinantes para o controle da infiltração e consequentemente para a longevidade dos procedimentos clínicos.restauradores. No entanto, a adesão ao tecido dentinário ainda é crítica devido às características estruturais e composição deste substrato. Além disso, o selamento das restaurações pode ser afetado por estresses mecânicos, térmicos e químicos. Para minimizar a ocorrência de falhas, tem sido proposto o uso de diferentes técnicas restauradoras. Este estudo in vitro teve como objetivos avaliar a influência das ciclagens térmica e mecânica na ocorrência de nanoinfiltração e na resistência de união de restaurações classe II com margens cervicais em dentina utilizando diferentes técnicas restauradoras: RC -resina composta Filtek Supreme Plus (3M/ESPE); RMGIC + RC -cimento de ionômero de vidro modificado por resina Vitrebond Plus (3M/ESPE) + RC; e RF + RC -resina de baixa viscosidade Filtek Supreme Plus Flowable (3M/ESPE) + RC. Para isso, foi utilizado sistema adesivo Adper Single Bond Plus (3M/ESPE) aplicado após condicionamento ácido total. Após, as restaurações foram subdivididas aleatoriamente em 2 grupos: Envelhecido -ciclagens térmica -3.000 ciclos, 20-80°C -e mecânica -500.000 ciclos, 50N; e Controle -armazenagem em água destilada a 37°C. Para a avaliação da nanoinfiltração, os dentes foram imersos por 24 horas em solução de 50% de nitrato de prata amoniacal e a seguir, foram expostos a solução foto-reveladora. Foram obtidas duas secções longitudinais as quais foram embutidas em resina epóxi e preparadas para análise em microscopia eletrônica de varredura (MEV). A infiltração de nitrato de prata foi calculada pela porcentagem total de penetração na margem cervical e pela área de deposição de partículas de prata expressa em µm2. Para a avaliação da resistência de união, as restaurações foram seccionadas longitudinalmente para obtenção de duas fatias. Estas foram desgastadas em formato de ampulheta reduzindo a interface de união para 1 mm2. Os espécimes foram testados em microtração a uma velocidade de 1mm/min e os valores de resistência expressos em Mpa. Os dados de ambas as avaliações foram analisados pelos testes ANOVA e Tukey (p<0.05). O melhor desempenho foi obtido pelo grupo restaurado somente com resina composta, enquanto a realização das ciclagens térmica e mecânica alterou o desempenho das restaurações que utilizaram a resina de baixa viscosidade associada à resina composta. As restaurações com RMGIC + RC apresentaram o pior desempenho independentemente da realização das ciclagens térmica e mecânica(AU)

The formation of an effective interface between tooth and restorative material is the major factor in preventing the occurrence of leakage and consequently determining the longevity of the restorative treatment. However, adhesion to dentin still is a concern due to its structural characteristics and composition. Hence the mechanical, thermal and chemical stresses may cause failure in restorations sealing. In order to minimize the effects of these stresses, it has been proposed the use of different restorative techniques. The objectives of this in vitro study were to evaluate the influence of mechanical and thermal cycling on nanoleakage and bond strength of class II restorations with gingival margins in dentin restored with the following techniques: RC - composite resin Filtek Supreme Plus (3M/:ESPE); RMGIC + RC -resin modified glass ionomer cement Vitrebond Plus (3M/ESPE) + RC; and RF + RC - flowable resin Filtek Supreme Plus Flowable (3M/ESPE) + RC. The adhesive system Adper Single Bond Plus (3M/ESPE) was used and placed after acid etching. Then, the restorations were randomly subdivided into two groups: Aging -thermal -3.000 cycles, 20-80°C and mechanical cycling -500.000 cycles, 50N; and Control- kept in distilled water at 37°C. Teeth were immersed in 50% w/v ammoniacal silver nitrate for 24 hours and then, were immersed in a photo-developer solution for nanoleakage evaluation. Two longitudinal sections were obtained and embedded in epoxy resin and analyzed using scanning electron microscopy (SEM). The leakage was calculated as the total percentage of silver nitrate deposition in gingival margin and also as the area of silver nitrate deposition in µm2. For the bond strength evaluation, the restorations were sectioned longitudinally to obtain 2 slabs. The slabs were trimmed in hourglass to produce cross-sectional area of 1mm2. The specimens were tested in tensile at 1mm / min and the values were expressed in Mpa. The data from both evaluations were analyzed by ANOVA and Tukey tests (p <0.05). The best results were obtained for the teeth restored with composite resin alone, while the detrimental effect of the simulated aging were significant only when the flowable resin was used in incremental technique. The groups restored with RMGIC presented the poorest performance regardless of the thermal and mechanical cycling procedures(AU)