Influence of Er:YAG and ND:YAG laser irradiation and fluoride application on surface roughness and dentin surface wear after erosive challenge - An in vitro study.

Background: To evaluate the effectiveness of Er:YAG and Nd:YAG laser on dentin hypersensitivity prevention, associated or not to acidulated phosphate fluoride (APF) after erosive challenge. Material and Methods: 104 specimens were obtained from bovine dentine and divided into groups (n=13): G1: Er:YAG; G2: Er:YAG followed by application of APF; G3: application of APF followed by Er:YAG, simultaneously; G4: Nd:YAG; G5: Nd:YAG followed by application of APF; G6: application of APF followed by Nd:YAG, simultaneously; G7:application of APF; G8: untreated. The parameters for Er:YAG were:10s, distance of 4mm, water cooling flow of 2mL/min, 2Hz, 3.92J/cm2. For the Nd:YAG: 10s, distance of 1mm, without cooling, 10Hz, 70.7J/cm2. The erosive drink was a cola at 4°C, 3×/day for 1 minute, for 5 days. Roughness and wear analysis were done in confocal laser microscope. Data were statistically analyzed (α=0.05). Results: As regards roughness, there was no statistically difference among the groups. The groups irradiated with Er:YAG had a volume loss lower. G6 showed higher values than the groups irradiated with Er:YAG and lower than the other groups. The other groups irradiated with Nd:YAG showed similar wear results to the control. Conclusions: The Er:YAG laser showed the lowest volume loss from wear analysis, suggesting the increased the acid resistance of dentin. Key words:Dentine sensitivity, Lasers, Sodium fluoride.

Influence of preventive remineralizing techniques on surface roughness and volume loss of dentin submitted to erosive and/or abrasive challenges.

Background: The objective this study was to evaluate the influence of preventive remineralizing techniques on surface roughness and volume loss of dentin submitted to erosive and/or abrasive challenges. Material and Methods: One hundred and eighty specimens of bovine root dentin were made; half of each was isolated (without treatment - WT) and half was subjected to the following remineralizing techniques: fluoride varnish (FV); Regenerate Boosting Serum® (RBS); Er,Cr:YSGG laser (L); fluoride varnish+laser (FV+L); Regenerate Boosting Serum®+laser (RBS+L). The specimens were submitted to erosive, abrasive and erosive followed by abrasive challenge. Erosion was carried out for 5 minutes, twice a day for 10 days. Abrasion was performed with an electric toothbrush and slurry solution for 60 seconds. The evaluation was performed by confocal laser scanning microscopy. Analysis of variance and Tukey tests were used for surface roughness; volume loss comparison was performed using the Kruskal-Wallis test and Dunn's post-hoc (p<0.05). Results: There was no statistically significant difference in the surface roughness of the reference area in relation to the areas submitted to different types of treatment and challenges (p>0.05). Regarding volume loss, the untreated group submitted to erosive/abrasive challenges showed greater percentage of volume loss compared to the other groups (p<0.05). Conclusions: It is concluded that preventive remineralizing techniques are effective in maintaining dentin volume after erosive/abrasive challenges. Key words:YSGG lasers, Dentin, Erosion, Tooth Abrasion.

The effects of re-irradiation on the chemical and morphological properties of permanent teeth.

This study aimed to assess the in vitro effects of re-irradiation on enamel and dentin properties, simulating head and neck cancer radiotherapy retreatment. Forty-five human permanent molars were classified into five groups: non-irradiated; irradiated 60 Gy, and re-irradiated with doses of 30, 40, and 50 Gy. Raman spectroscopy, scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS) were employed for analysis. Raman spectroscopy assessed intensity, spectral area, and specific peaks comparatively. Statistical analysis involved Kolmogorov-Smirnov and One-Way ANOVA tests, with Tukey's post-test (significance level set at 5%). Significant changes in irradiated, non-irradiated, and re-irradiated enamel peaks were observed, including phosphate (438 nm), hydroxyapatite (582 nm), phosphate (960 nm), and carbonate (1070 nm) (p < 0.05). Re-irradiation affected the entire tooth (p > 0.05), leading to interprismatic region degradation, enamel prism destruction, and hydroxyapatite crystal damage. Dentin exhibited tubule obliteration, crack formation, and progressive collagen fiber fragmentation. EDX revealed increased oxygen percentage and decreased phosphorus and calcium post-reirradiation. It is concluded that chemical and morphological changes in irradiated permanent teeth were dose-dependent, exacerbated by re-irradiation, causing substantial damage in enamel and dentin.

Efficacy of ClinproTMXT Varnish surrounding brackets on the enamel surface of white spot lesion.

Orthodontics patients usual develop demineralization and present cavity caries lesions after six months. Minimally invasive procedures have been the goal in modern dental practice. The aim of this study was to evaluate the effect of ClinproTMXT Varnish, on the enamel surface roughness and severity of white spot lesions. Twenty premolars were submitted to bond brackets and experimental induction of demineralization and randomly divided into 2 groups: GI - fluoride varnish (Colgate Duraphat®); GII - Ionomeric Sealant (ClinproTMXT Varnish). The treatment was applied around the brackets. The surface roughness of specimens was analyzed, before treatment and 12 weeks after treatment by laser confocal microscopy, and the severity of the white spot lesion was by laser fluorescence device. The data were analyzed by non-parametric Wilcoxon and Mann-Whitney Test, at 5% significance, roughness percentage reduction was performed. The severity of demineralization decreased in both, GI (p = 0.005) and GII (p = 0.019). Enamel superficial roughness levels decreased in GI and GII. As well as the roughness percentage, being more expressive in the ClinproTMXT Varnish group (85,09%). Colgate Duraphat® or Clinpro™ XT Varnish reduced the severity of the demineralization and decreased the superficial roughness on the enamel. The Clinpro™ XT Varnish was superior to superficial roughness on enamel.

Efficacy of ClinproTMXT Varnish surrounding brackets on the enamel surface of white spot lesion

Abstract Orthodontics patients usual develop demineralization and present cavity caries lesions after six months. Minimally invasive procedures have been the goal in modern dental practice. The aim of this study was to evaluate the effect of ClinproTMXT Varnish, on the enamel surface roughness and severity of white spot lesions. Twenty premolars were submitted to bond brackets and experimental induction of demineralization and randomly divided into 2 groups: GI - fluoride varnish (Colgate Duraphat®); GII - Ionomeric Sealant (ClinproTMXT Varnish). The treatment was applied around the brackets. The surface roughness of specimens was analyzed, before treatment and 12 weeks after treatment by laser confocal microscopy, and the severity of the white spot lesion was by laser fluorescence device. The data were analyzed by non-parametric Wilcoxon and Mann-Whitney Test, at 5% significance, roughness percentage reduction was performed. The severity of demineralization decreased in both, GI (p = 0.005) and GII (p = 0.019). Enamel superficial roughness levels decreased in GI and GII. As well as the roughness percentage, being more expressive in the ClinproTMXT Varnish group (85,09%). Colgate Duraphat® or Clinpro™ XT Varnish reduced the severity of the demineralization and decreased the superficial roughness on the enamel. The Clinpro™ XT Varnish was superior to superficial roughness on enamel.

Resumo Pacientes ortodônticos geralmente desenvolvem desmineralização e apresentam lesões de cárie após seis meses de tratamento. Procedimentos minimamente invasivos têm sido o objetivo na prática odontológica moderna. O objetivo deste estudo foi avaliar o efeito do ClinproTM XT selante ionomérico, ao redor do bráquete, com relação a rugosidade superficial do esmalte e a severidade da lesão induzida. Vinte pré-molares foram submetidos a colagem de bráquetes e indução experimental de desmineralização e divididos aleatoriamente em 2 grupos: GI - verniz fluoretado (Colgate Duraphat®); GII - Selante Ionomérico (ClinproTM XT). O tratamento foi aplicado ao redor dos bráquetes. A rugosidade da superfície dos espécimes foi analisada, antes do tratamento e 12 semanas após o tratamento por microscopia confocal a laser e severidade da lesão de mancha branca por dispositivo de fluorescência a laser. Os dados foram analisados pelo teste não paramétrico de Wilcoxon e Mann-Whitney, a 5% de significância. A taxa de redução da lesão foi calculada. A severidade da desmineralização diminuiu tanto no GI (p = 0,005) quanto no GII (p = 0,019). Os níveis de rugosidade superficial do esmalte diminuíram no GI e GII, assim como o percentual de rugosidade, sendo mais expressivo no grupo ClinproTMXT (85,09%). Colgate Duraphat® e Clinpro™ XT reduziram a severidade da desmineralização e diminuíram a rugosidade superficial do esmalte. O selante ionomérico Clinpro™ XT foi superior na redução percentual de rugosidade.

Treatment outcome for dentin hypersensitivity with laser therapy: Systematic review and meta-analysis.

BACKGROUND: Laser protocols for the treatment of dentin hypersensitivity (DH) have not yet been studied systematically. OBJECTIVES: The present study aimed to review clinical trials on the treatment of DH with laser therapy through a systematic review and meta-analysis. MATERIAL AND METHODS: The search of electronic databases resulted in 562 publications up to April 2020. The inclusion criteria were studies carried out on humans and reporting on the treatment of DH with laser therapy. Case reports, literature reviews and systematic reviews were excluded. Selected by abstract, potentially eligible papers were read in full (n = 160). Independent examiners performed data extraction and the assessment of the risk of bias. RESULTS: A total of 34 studies were included in the analysis, and 11 in the quantitative analysis. It was observed that most studies followed up patients for a maximum of 6 months (55%). Through the meta-analysis, we observed statistically significant differences between the average pain before and after 3 months of treatment with highand low-power lasers. However, through indirect comparisons, it was observed that the high-power laser showed a greater tendency to reduce the pain levels after 3 months of treatment as compared to the low-power laser, but without a statistically significant difference. CONCLUSIONS: It was possible to conclude that regardless of the type of laser used in the treatment of DH, this treatment is an effective option for the control of pain symptoms. However, it was not possible to establish a defined treatment protocol, since the evaluation methods are very different from each other. Text for Rewiew and clinical cases.

In vitro study of structural and mechanical properties of latex and non-latex intermaxillary orthodontic elastics.

PURPOSE: We evaluated bacterial endotoxin adhesion, superficial micromorphology and mechanical properties of latex and non-latex intermaxillary orthodontic elastics. METHODS: To quantify the adhered bacterial endotoxin, elastics were divided into 5 groups: experimental (n = 12) latex and non-latex elastics, previously contaminated by an endotoxin solution, negative control (n = 6) latex and non-latex elastics without contamination, and positive control (n = 6) stainless steel specimens (metallic replicas), contaminated by an endotoxin solution. In parallel, the structural micromorphology (n = 6) and surface roughness of latex and non-latex intermaxillary orthodontic elastics were assessed using confocal laser microscopy. Force degradation (g) and deformation of the internal diameter change (mm) were also evaluated. Structural micromorphology, surface roughness (µm), force degradation (g) and internal diameter (mm) change were evaluated at time 0 and after 24 and 72 h in a deformation test. Data were analyzed by the Shapiro-Wilk, Kruskal-Wallis, Dunn, ANOVA and Bonferroni tests (α = 5%). RESULTS: Endotoxin adhered similarly to both types of elastics with scores of 3 (> 1.0 EU/mL). The surface microstructure of both types of elastics showed irregularities and porosities at all times. Initially, the latex elastics had a higher surface roughness (p < 0.001) than the non-latex ones. After 24 h loading, surface roughness of the latex elastics was significantly reduced (p < 0.001), while after 72 h, the values were similar for both types (p > 0.05). The non-latex elastics had significantly higher force generation values (p < 0.05) at 0, 24 and 72 h compared with the latex elastics, although there was a significant reduction (p < 0.001) in force over time for both elastics. Despite similar initial values, non-latex elastics had a significantly larger internal diameter (p < 0.001) after the loading periods of 24 and 72 h compared with the latex elastics. CONCLUSION: Both elastics showed high affinity with endotoxin and microstructural irregularities of their surface. The non-latex elastics generated higher force values but demonstrated greater deformation of the internal diameter after loading.

Effect of an experimental chitosan/casein gel on demineralized enamel under a cariogenic challenge.

BACKGROUND: Dental caries is considered one of the most common oral health diseases. OBJECTIVES: The aim of the study was to evaluate the effects of an experimental chitosan/casein gel on enamel demineralization/remineralization in an environment with a high cariogenic challenge. MATERIAL AND METHODS: Thirty-six specimens of bovine enamel (4 mm × 3 mm × 2 mm) were ground flat and polished. Then, the specimens were immersed in acetate buffer for 43 h with half of the surface protected (serving as control) and the other half exposed. All demineralized surfaces were randomly assigned into 3 groups (n = 12 per group) according to the type of treatment (G1 - control, G2 - 1.5% chitosan gel with 1.5% casein, and G3 - 1.5% chitosan gel without casein), and the corresponding treatment was applied once a week for 3 weeks. The specimens were also subjected to pH cycles of demineralization/ remineralization and the treatments were performed 3 times at 7-day intervals for a total of 21 days. Surface images were obtained for the analysis of initial roughness and, after the cariogenic challenge, new images were obtained to evaluate the final roughness, volume loss and wear profile using laser confocal microscopy. After the analyses, the specimens were cut and the depth of demineralization was measured. The data were analyzed using the Kruskal-Wallis analysis of variance (ANOVA) and the Tukey's test. RESULTS: While the chitosan gel with casein showed a similar loss to the control group (p > 0.05), both gels resulted in similar volume loss (p > 0.05). There were no statistical differences regarding the wear profile, surface roughness and depth of demineralization between the groups (p > 0.05). CONCLUSIONS: The chitosan gel reduced volume loss of the demineralized enamel without significantly impacting the surface smoothness.

Effect of erosive challenge with HCl on restorative materials.

OBJECTIVE: Investigate the effect of erosive challenge with hydrochloric acid (HCl) on the surface of five different restorative materials. MATERIAL AND METHODS: Ten plates of five restorative materials (Admira Fusion, Activa BioActive-Restorative, Charisma, Equia Forte HT Fil/EF, Filtek Universal Restorative/FU) were obtained. Half of the plate surfaces was covered with an adhesive tape, creating a control area, and the other side was submitted to the HCl (0.06 M HCl; pH 1.2; at 37 °C; for 30 h). Plates with control and HCl-treated areas were analyzed regarding the surface roughness (Sa), roughness profile (Rv), surface loss (SL), microhardness (MI), and gloss (GL) (n = 10). Surface morphology was analyzed by SEM and chemical elements were identified by EDX (n = 5). Data were evaluated by ANOVA and Tukey's test (α = 0.05). RESULTS: Most materials were not affected by HCl. FU showed the lowest Sa and Rv, and the highest GL after HCl. On the other hand, EF presented the highest Sa, Rv, and SL, and the lowest GL. The MI of materials was not changed after HCl. Topographical and chemical alterations were observed after HCl only for EF. CONCLUSIONS: The composites showed minor surface changes after HCl, which was not observed for the glass ionomer cement (EF). FU presented the best performance regarding the parameters evaluated. CLINICAL RELEVANCE: The effects of erosive challenge with HCl on composites were minimal, while the glass ionomer cements might not be indicated as restorative material for patients with gastroesophageal reflux disease.

Influence of diode laser treatment and casein phosphopeptide-amorphous calcium phosphate paste on eroded root dentin.

Introduction: It is still unclear whether the pretreatment for dentin hypersensitivity can interfere with the adhesive-dentin bonding strength. This study aimed to evaluate in vitro the effect of pretreatment with a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste and diode laser on the shear bond strength of the etch-and-rinse adhesive system in the adhesive-dentin interface. Materials and Methods: Seventy-five bovine root specimens were randomly divided into five experimental groups (n = 15). Samples were eroded by six cycles of immersion in hydrochloric acid solution (0.01M; pH = 1.2) for 20 s each, at 45 min intervals, and treated with: G2 - no treatment, G3 - CPP-ACP, G4 - diode laser (970 nm), and G5 - CPP-ACP + Diode laser. After treatments, the morphology of the specimens was analyzed. Results: The fracture mode of each group was evaluated after restoration with composite resins in the treated area. Data were analyzed by the one-way ANOVA and Tukey's test (P < 0.05). G3 showed the highest values for shear bond strength; there was no significant difference among G1, G3, and G5 (P > 0.05). The adhesive fracture was predominant for all groups. Conclusion: The use of desensitizers containing CPP-ACP, associated or not with a diode laser, increased the bond strength of the etch-and-rinse adhesive system on eroded root dentin.

Microhardness homogeneity of RBCs light-cured with a multiple-peak LED and surface characterization after wear.

This in vitro study evaluated the effect of the beam homogeneity of a multiple-peak light-curing unit on the surface microhardness and the effect of toothbrushing wear on the microhardness, surface roughness, roughness profile, volume loss, and gloss retention of incremental and bulk-fill resin-based composites (RBCs). A LED light-curing unit (VALO) with four LEDs at the tip end (405, 445, 465A, and 465B nm emission peak) was used according to each manufacturer-recommended time to obtain disks (n=10) of six RBCs: Estelite Sigma Quick, Charisma Classic, Tetric EvoCeram Bulk Fill, Filtek Z250, Filtek Supreme Ultra, and Filtek Bulk Fill. Microhardness values were obtained according to each LED positioning of the light-curing unit on the top surface of the RBCs and were analyzed before and after toothbrushing regarding microhardness, surface roughness, roughness profile, volume loss, and gloss retention. Microhardness was considered homogeneous on the top surface regardless of the type of RBC or wavelength tested (p>0.05). Overall, toothbrushing did not reduce the microhardness of the RBCs but influenced the gloss values for most RBCs (p<0.001). Charisma Classic presented the greatest surface roughness and roughness profile after toothbrushing (p<0.05). Volume loss did not differ among RBCs (p>0.05). In conclusion, different wavelengths of the LED did not affect the top surface microhardness, regardless of the RBCs tested; and bulk-fill composites presented similar surface changes (microhardness, surface roughness, roughness profile, volume loss, and gloss retention) when compared to conventional composites after toothbrushing.

Sports mouthguards: Contamination, roughness, and chlorhexidine for disinfection - A randomized clinical trial

Abstract The aim of the present in vivo study was to evaluate the bacterial contamination of sports mouthguards, surface roughness, and the efficacy of chlorhexidine gluconate spray in the disinfection of these devices. A randomized, blinded cross-over clinical trial was performed with twenty 9 to 13 years old children who practiced martial arts and participated in all phases of the study. They were instructed to wear mouthguards 3 alternated days a week for 1 hour and, after use, to spray sterile tap water or chlorhexidine 0.12%. The mouthguards were analyzed by MTT assay, Checkerboard DNA-DNA hybridization, and confocal laser microscopy prior and after use for 2 weeks. Data were analyzed by Wilcoxon and t-Student, and Pearson correlation tests, with 5% significance level. Were observed that mouthguards of the control group were more contaminated with cariogenic microorganisms than those of the chlorhexidine group (p<0.05). The mouthguards use of spray of chlorhexidine reduced significantly the bacteria contamination compared with control group (p = 0.007). The surface roughness of the mouthguards increased significantly after use, irrespective of application of chlorhexidine spray. A moderate correlation (r=0.59) was observed between surface roughness and the cariogenic microorganism's contamination only for control group. Sports mouthguards had intense microbial contamination and increased surface roughness after its use. The use of chlorhexidine spray was effective for reducing the mouthguards contamination used by children.

Resumo O objetivo do presente estudo in vivo foi avaliar a contaminação bacteriana de protetores bucais esportivos, a rugosidade da superfície e a eficácia do spray de gluconato de clorexidina na desinfecção desses dispositivos. Um ensaio clínico randomizado, cego, cruzado foi realizado com vinte crianças de 9 a 13 anos, que praticavam artes marciais, participaram de todas as fases do estudo. As crianças foram orientadas a usar o protetor bucal por 3 dias alternados durante 1 hora e, após o uso, borrifar água de torneira estéril ou clorexidina 0,12%. Os protetores foram analisados por ensaio MTT, Hibridização DNA-DNA e microscopia confocal a laser antes e após o uso por 2 semanas. Os dados foram analisados pelos teste de Wilcoxon, teste t de Student, e correlação de Pearson, com nível de significância de 5%. Observou-se que os protetores bucais do grupo controle estavam mais contaminados com microrganismos cariogênicos do que os do grupo experimental (clorexidina) (p <0,05). O uso de protetores bucais com spray de clorexidina reduziu significativamente a contaminação bacteriana em relação ao grupo controle (p = 0,007). A rugosidade da superfície dos protetores bucais aumentou significativamente após o uso, independentemente da aplicação de spray de clorexidina. Uma correlação moderada (r = 0,59) foi observada entre a rugosidade da superfície e a contaminação do micro-organismo apenas para o grupo controle. Os protetores bucais esportivos apresentam intensa contaminação microbiana e aumento da rugosidade superficial após o uso. O uso de spray de clorexidina foi eficaz para reduzir a contaminação dos protetores bucais usados por crianças.

Microhardness homogeneity of RBCs light-cured with a multiple-peak LED and surface characterization after wear

Abstract This in vitro study evaluated the effect of the beam homogeneity of a multiple-peak light-curing unit on the surface microhardness and the effect of toothbrushing wear on the microhardness, surface roughness, roughness profile, volume loss, and gloss retention of incremental and bulk-fill resin-based composites (RBCs). A LED light-curing unit (VALO) with four LEDs at the tip end (405, 445, 465A, and 465B nm emission peak) was used according to each manufacturer-recommended time to obtain disks (n=10) of six RBCs: Estelite Sigma Quick, Charisma Classic, Tetric EvoCeram Bulk Fill, Filtek Z250, Filtek Supreme Ultra, and Filtek Bulk Fill. Microhardness values were obtained according to each LED positioning of the light-curing unit on the top surface of the RBCs and were analyzed before and after toothbrushing regarding microhardness, surface roughness, roughness profile, volume loss, and gloss retention. Microhardness was considered homogeneous on the top surface regardless of the type of RBC or wavelength tested (p>0.05). Overall, toothbrushing did not reduce the microhardness of the RBCs but influenced the gloss values for most RBCs (p<0.001). Charisma Classic presented the greatest surface roughness and roughness profile after toothbrushing (p<0.05). Volume loss did not differ among RBCs (p>0.05). In conclusion, different wavelengths of the LED did not affect the top surface microhardness, regardless of the RBCs tested; and bulk-fill composites presented similar surface changes (microhardness, surface roughness, roughness profile, volume loss, and gloss retention) when compared to conventional composites after toothbrushing.

Resumo Este estudo in vitro avaliou a homogeneidade do feixe de um fotopolimerizador de múltiplos picos na microdureza superficial e o efeito da escovação na microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e retenção do brilho de compósitos a base de resina (RBCs) incrementais ou bulk-fill. Um fotopolimerizador LED (VALO) com quatro LEDs na ponteira (405, 445, 465A e 465B nm de pico de emissão) foi usado de acordo com o tempo recomendado por cada fabricante para obtenção de discos (n=10) de seis RBCs: Estelite Sigma Quick, Charisma Classic, Tetric EvoCeram Bulk Fill, Filtek Z250, Filtek Supreme Ultra e Filtek Bulk Fill. Os valores de microdureza foram obtidos seguindo o posicionamento de cada LED na superfície superior das amostras e foram analisados antes e após a escovação quanto a microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e retenção do brilho. A microdureza foi considerada homogênea no topo da superfície, independentemente do tipo de RBCs ou comprimento de onda testados (p>0.05). No geral, a escovação não reduziu a microdureza das RBCs, mas influenciou o brilho para a maioria das RBCs (p<0.001). Charisma Classic apresentou os maiores valores de rugosidade superficial e perfil de rugosidade após a escovação (p<0.05). A perda de volume não diferiu entre as RBCs (p>0.05). Em conclusão, os diferentes comprimentos de onda do LED não alteraram a microdureza do topo da superfície, independentemente das RBCs testadas; e as resinas bulk-fill apresentaram alterações superficiais similares (microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e manutenção do brilho) quando comparadas às resinas convencionais após a escovação.

Effect of toothbrushing on the surface of enamel, direct and indirect CAD/CAM restorative materials.

PURPOSE: To determine the effects of tooth brushing on the surface roughness (Sa) and morphology, maximum relative depth (Rv), gloss (GU), and microhardness (MH) of four esthetic restorative materials and enamel. MATERIALS AND METHODS: A light-curing composite resin (Filtek Supreme Ultra [FSU], 3M ESPE), two hybrid resin/ceramic CAD/CAM materials (Lava Ultimate [LAV], 3M ESPE, and VITA Enamic [VEN], VITA Zahnfabrik), and a CAD/CAM feldspathic ceramic (VITA Blocs Mark II [VMA], VITA Zahnfabrik) were evaluated. Bovine enamel (ENA) was used as a control group. All surfaces were polished in accordance with the manufacturer's instructions. Samples were analyzed before and after brushing (30,000 cycles) regarding Sa and Rv using a 3D laser-measuring microscope. GU was evaluated every 10,000 tooth brushing cycles. MH was also measured before and after tooth brushing. The surfaces were observed using scanning electron and laser measuring microscopies to determine the wear patterns. Data were analyzed by paired t test, one-way or two-way repeated measures analysis of variance, and Tukey test (α = .05), depending on the method performed. RESULTS: The Sa increased significantly after brushing for all materials, except for VMA, which showed the opposite effect. ENA and VEN showed higher Rv than VMA. After 30,000 tooth brushing cycles, VMA showed the highest GU, while FSU showed the lowest. Also, little surface topography changes were observed for VMA. MH did not change significantly after 30,000 brushing cycles, except for LAV. CONCLUSION: Brushing caused surface alterations in all tested materials except for feldspathic ceramic. The changes were more evident in resin-based materials.

Influence of Er,Cr:YSGG laser on root dentin submitted to erosive and/or abrasive challenges.

This study evaluated how Er,Cr:YSGG laser, associated or not with 5% fluoride varnish, influences the surface roughness and volume loss of bovine root dentin submitted to erosive and/or abrasive wear. One hundred and twenty dentin specimens were divided into the groups: without preventive treatment (WPT), 5% fluoride varnish (FV); Er,Cr:YSGG laser irradiation (L), and varnish combined with laser (FV + L). The specimens (n = 10) were subdivided into: 1 = erosion (E); 2 = abrasion (A); and 3 = erosion followed by abrasion (E + A). The erosive solution used was a soft-drink (pH = 2.42 at 4ºC) applied in 5-min cycles twice a day for 10d. Abrasive wear involved brushing for 60s with an electric brush (1,600-oscillations/s) at a load of 2.0N. Surface roughness and volume loss were evaluated using a laser scanning confocal microscope. Roughness data were submitted to one-way ANOVA and Tukey post-hoc test. For volume loss, the Kruskal-Wallis and Dunn's post-hoc tests were used (α = 5%). The lowest values of roughness were found in the control areas of all subgroups (p > 0.05). In the experimental area, the [(WPT) + (E+A)] subgroup had a significantly higher roughness (5.712 ± 0.163 µm 2 ) than the other subgroups (p < 0.05). The L and (FV + L) groups had statistically similar roughness, regardless of the type of wear. The (FV + L) group had the lowest volume loss, regardless of the type of wear performed: [(FV + L) + (E)] = 7.5%, [(FV + L) + (A) = 7.3%, and [(FV + L) + (E + A)] = 8.1%. The subgroup [(WPT) + (E + A)] had the highest volume loss (52.3%). The proposed treatments were effective in controlling dentin roughness. Laser irradiation can be an effective method to increase root dentin resistance after challenges and limit problems related to non-carious lesions.

Sports mouthguards: Contamination, roughness, and chlorhexidine for disinfection - A randomized clinical trial.

The aim of the present in vivo study was to evaluate the bacterial contamination of sports mouthguards, surface roughness, and the efficacy of chlorhexidine gluconate spray in the disinfection of these devices. A randomized, blinded cross-over clinical trial was performed with twenty 9 to 13 years old children who practiced martial arts and participated in all phases of the study. They were instructed to wear mouthguards 3 alternated days a week for 1 hour and, after use, to spray sterile tap water or chlorhexidine 0.12%. The mouthguards were analyzed by MTT assay, Checkerboard DNA-DNA hybridization, and confocal laser microscopy prior and after use for 2 weeks. Data were analyzed by Wilcoxon and t-Student, and Pearson correlation tests, with 5% significance level. Were observed that mouthguards of the control group were more contaminated with cariogenic microorganisms than those of the chlorhexidine group (p<0.05). The mouthguards use of spray of chlorhexidine reduced significantly the bacteria contamination compared with control group (p = 0.007). The surface roughness of the mouthguards increased significantly after use, irrespective of application of chlorhexidine spray. A moderate correlation (r=0.59) was observed between surface roughness and the cariogenic microorganism's contamination only for control group. Sports mouthguards had intense microbial contamination and increased surface roughness after its use. The use of chlorhexidine spray was effective for reducing the mouthguards contamination used by children.

Influence of Er, Cr: YSGG laser on root dentin submitted to erosive and/or abrasive challenges

Abstract This study evaluated how Er,Cr:YSGG laser, associated or not with 5% fluoride varnish, influences the surface roughness and volume loss of bovine root dentin submitted to erosive and/or abrasive wear. One hundred and twenty dentin specimens were divided into the groups: without preventive treatment (WPT), 5% fluoride varnish (FV); Er,Cr:YSGG laser irradiation (L), and varnish combined with laser (FV + L). The specimens (n = 10) were subdivided into: 1 = erosion (E); 2 = abrasion (A); and 3 = erosion followed by abrasion (E + A). The erosive solution used was a soft-drink (pH = 2.42 at 4ºC) applied in 5-min cycles twice a day for 10d. Abrasive wear involved brushing for 60s with an electric brush (1,600-oscillations/s) at a load of 2.0N. Surface roughness and volume loss were evaluated using a laser scanning confocal microscope. Roughness data were submitted to one-way ANOVA and Tukey post-hoc test. For volume loss, the Kruskal-Wallis and Dunn's post-hoc tests were used (α = 5%). The lowest values of roughness were found in the control areas of all subgroups (p > 0.05). In the experimental area, the [(WPT) + (E+A)] subgroup had a significantly higher roughness (5.712 ± 0.163 μm 2 ) than the other subgroups (p < 0.05). The L and (FV + L) groups had statistically similar roughness, regardless of the type of wear. The (FV + L) group had the lowest volume loss, regardless of the type of wear performed: [(FV + L) + (E)] = 7.5%, [(FV + L) + (A) = 7.3%, and [(FV + L) + (E + A)] = 8.1%. The subgroup [(WPT) + (E + A)] had the highest volume loss (52.3%). The proposed treatments were effective in controlling dentin roughness. Laser irradiation can be an effective method to increase root dentin resistance after challenges and limit problems related to non-carious lesions.

Different approaches for aesthetic rehabilitation of discolored nonvital anterior teeth / Diferentes abordagens para reabilitação estética de dentes anteriores escurecidos não-vitais

ABSTRACT An ideal aesthetic standard consists of facial and smile harmony. Discolored teeth generally cause an imbalance in facial aesthetics, leading to low self-esteem and disturbance in social relationships. Causes of teeth discoloration are classified as intrinsic or extrinsic. Bleaching is considered a safe and effective treatment for discolored nonvital teeth and can be associated with restorative treatment to properly correct the dental color and maximize the aesthetic results. This paper aims to present two case reports of single discolored nonvital anterior teeth and the protocol used to reestablish the dental harmony of these patients by bleaching and direct composite resin restoration. To exert minimally invasive dentistry is very important to preserve tooth structure and reduce the risk of fracture. Internal bleaching, although may not be sufficient to reestablish the aesthetic in some cases, it is important to minimize dental preparation to perform an indirect or direct restoration. Dentists must take into account the patients expectations, dominate the restorative technique and know the dental materials to properly be able to restore function and aesthetics and consequently improve life quality and social relationships.

RESUMO Um padrão estético ideal consiste na harmonia facial e do sorriso. Dentes descoloridos geralmente causam um desequilíbrio na estética facial, levando a baixa auto-estima e interferência nas relações sociais. As causas da descoloração dos dentes são classificadas como intrínsecas ou extrínsecas. O clareamento é considerado um tratamento seguro e eficaz para os dentes não vitais escurecidos e pode ser associado ao tratamento restaurador para corrigir adequadamente a cor dental e maximizar os resultados estéticos. O objetivo deste trabalho é apresentar dois relatos de casos de dentes anteriores não vitais escurecidos e o protocolo utilizado para restabelecer a harmonia dentária desses pacientes por meio de clareamento e restauração direta em resina composta. Para exercer uma Odontologia minimamente invasiva é muito importante preservar a estrutura dentária e reduzir o risco de fratura. O clareamento interno, embora possa não ser suficiente para restabelecer a estética em alguns casos, é importante para minimizar o preparo dental para realizar uma restauração indireta ou direta. Os dentistas devem levar em consideração as expectativas dos pacientes, dominar a técnica restauradora e conhecer os materiais dentários para poder restaurar adequadamente a função e a estética e, consequentemente, melhorar a qualidade de vida e as relações sociais.

Effect of Duodenogastric Reflux on Dental Enamel.

PURPOSE: To evaluate the effects of stomach and duodenal fluid on enamel surfaces, simulating the action of refluxed liquid in patients with duodenogastric reflux. METHODS AND MATERIALS: Forty bovine incisors were used to obtain enamel fragments. Only half of the enamel surface was exposed to erosive challenges; the samples were then randomly divided into the following four groups (n = 10): G1: HCl; G2: HCl + pepsin; G3: HCl + ox bile + NaHCO3; and G4: HCl + pancreatin + NaHCO3. The specimens were placed in 37°C solutions, six times per day, for 20 s, over a period of 5 days and then analysed for morphology, surface roughness and the step formed on the dental enamel using confocal laser microscopy. The data were analysed using the Kruskal-Wallis and Dunn's test (p <0.05). RESULTS: Both analyses revealed a higher step and surface roughness for the G3 group (5.6 µm ± 1.69, 2.2 µm ± 1.61), which were statistically significant compared with the G1 and G2 groups (3.9 µm ± 1.5 µm; 1.0 µm ± 0.18; 3.7 µm ± 1.45; and 0.9 µm ± 0.12) (p <0.05); only the step in the G4 group (4.9 µm ± 1.8 µm) was similar to that of the G3 group (p >0.05). Morphological analysis showed greater structural loss in the G3 and G4 groups. CONCLUSIONS: Bile and pancreatin, in combination with hydrochloric acid, may promote a greater loss of structure, increased surface roughness and loss of enamel prismatic anatomy.

Radiotherapy Impairs Adhesive Bonding in Primary Teeth: An In Vitro Study.

Purpose: To evaluate the morphological alterations in enamel and dentin of primary teeth following radiotherapy (RT) and to determine the best adhesive technique and time to carry out restorative procedures.
Methods: Enamel and dentin fragments of primary teeth were randomly assigned into four groups (n=30): G1 (control)-non-irradiated, only restorative procedure; G2- restorative procedure immediately before RT; G3-restorative procedure 24 hours after RT; and G4-restorative procedure six months after RT. Each group was divided into one of two subgroups according to the adhesive system used for restoration: (1) AdperSingle Bond 2 (SB); and (2) ClearfillSE Bond (CL). The specimens were submitted to fractionated RT until they reached the final dose of 60 Gy. They were then subjected to confocal microscopy and the shear bond strength test. Data were analyzed using two-way analysis of variance followed by Tukey's tests ( α = five percent).
Results: Morphological changes were first observed in enamel and dentin after 40 Gy of irradiation. G4 bond strength values were similar to G1 in the CL and SB groups for enamel and in the CL group for dentin (P >0.05). G2 showed the lowest values for enamel and dentin (P <0.05). In G3, CL presented the highest strength values in enamel; for G4, the highest values were found in dentin (P <0.05).
Conclusions: Radiotherapy affected the morphological surface of enamel and dentin. The restorations placed immediately after RT had the weakest shear bond strength, and the restorations placed six months after RT had similar means of bond strength compared to the nonirradiated teeth in enamel, regardless of the adhesive system used. In dentin, CL showed better performance than SB.