Is prolonged bleaching more harmful to dental enamel than daily dietary and hygienic oral habits?

The ultrastructural and mechanical properties of enamel surface were evaluated after prolonged bleaching treatments with 10% carbamide peroxide in the presence or absence of orange juice (erosive challenge) and toothbrushing (abrasive challenge). In total, 145 incisor bovine teeth were used in this study. Twenty-five samples were prepared for the ultrastructural evaluations, and 120 samples were prepared for microhardness and roughness tests. These 120 samples were divided into eight experimental groups (n = 15): G1- artificial saliva; G2- abrasion; G3- erosion; G4- dental bleaching; G5- erosion + abrasion; G6- bleaching + abrasion; G7- bleaching + erosion; and G8- bleaching + erosion + abrasion. All groups were tested at T0 (before treatment), T1 (14 days), T2 (21 days), and T3 (28 days). Two-way analysis of variance for repeated measures and the post hoc Sidak tests (p ≤ 0.05) were used. The roughness evaluation demonstrated an increase in damage for all experimental groups with an increase in the time period. For microhardness, the groups exposed to artificial saliva (AS) and abrasive challenge did not show any differences at any time points, while the other groups showed a decrease in microhardness from T0 to T3. Ultrastructural evaluation showed different surface alterations in response to the treatments. Despite prolonged bleaching periods, the procedure caused lesser enamel surface alterations than exposure to orange juice alone or in combination with brushing.

Charcoal-based dentifrices: Effect on color stability and surface wear of resin composites.

OBJECTIVE: To evaluate the effect of charcoal-based dentifrices on the color change (CC) and surface wear (SW) of resin composites. MATERIALS AND METHODS: Five dentifrices, including three toothpastes: Colgate total-12 (C12), Black is the new White (CPX), and Natural (NAT); and two powders: Carvvo (CVV) and Whitemax (WMX), were evaluated. Composite blocks (5x5x2mm- Z350 3 M/ESPE, shade A2) were subjected to 417 and 5004 brushing cycles. The CC (n = 7, CIEDE2000; ΔE00 ) was evaluated using a spectrophotometer. SW (n = 5) was assessed using profilometry. The dentifrice particles were characterized by scanning electron microscopy (SEM). RESULTS: In 417 brushing cycles, resin composite exhibited higher color change upon being exposed to NAT, CVV and WMC than to C12 (p ≤ 0.05). In 5004 brushing cycles, resin composite showed higher color change values when exposed to all dentifrices, except C12 (p ≤ 0.05). The powders promoted higher SW on resin composite than C12 in both evaluation times (p ≤ 0.05). In 417 cycles, WMX caused higher SW on composite than C12, CPX, and NAT (p ≤ 0.05). No significant different SW was found between powders and charcoal-based toothpastes after 5004 brushing cycles (p > 0.05). SEM showed larger particles for powder than for toothpaste dentifrices. CONCLUSION: Within the limitations of this study, both null hypotheses have been rejected. Resin composites exposed to charcoal-based dentifrices exhibited significantly (p ≤ 0.05) higher color change and surface wear than conventional toothpastes. CLINICAL SIGNIFICANCE: Color change and surface wear shown by charcoal dentifrices may compromise the longevity of restorations.

In situ evaluation of desensitizing toothpastes for protecting against erosive tooth wear and its characterization.

OBJECTIVE: This five-phase, single-blind, crossover in situ trial evaluated the effects of desensitizing or anti-erosive toothpastes on dentin erosive wear and tubule occlusion. MATERIALS AND METHODS: Some characteristics such as relative dentin abrasivity (RDA), viscosity (V), cytotoxicity, and fluoride and calcium (Ca) availability of the toothpastes were also tested. Samples were positioned on removable intraoral appliances from 15 volunteers (n=4), according to the groups, C-control (0 ppm fluoride), F-sodium monofluorophosphate (MFP), A-MFP and arginine+calcium carbonate, CSP-calcium sodium phosphosilicate, and CS-MFP and calcium silicate+sodium phosphate. Erosion-abrasion cycling was performed (1% citric acid, 2min, 6×/day; toothbrushing, 5s, 2×/day). Surface loss (SL) was evaluated by optical profilometry. Environmental scanning electron microscopy images (ESEM) counted the number of open dentin tubules (ODTs). Data were statistically analyzed (α=0.05). RESULTS: There were no significant differences in SL among groups (p=0.468). The ODT for CSP, CS, and A groups were significantly lower than the control. CSP and CS presented significantly less ODT than F, but they did not significantly differ from A. F and CS were more abrasive than all the other toothpastes; CSP was more abrasive than A, and C was the least abrasive. CSP presented higher V (p<0.05). All toothpastes presented lower cell viability than the control without toothpaste exposure. F and A presented significantly higher values of F- (p<0.05). All fluoride toothpastes had similar amount of Ca, differing from the control (p<0.05). CONCLUSION: Although the toothpastes caused similar degree of erosive wear, CSP and CS were able to occlude the dentin tubules. CLINICAL RELEVANCE: Desensitizing toothpastes containing calcium, sodium, phosphate, and silicate could be a suitable option for treating dentin hypersensitivity.

Association of Nd:YAG laser and calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion.

OBJECTIVE: To evaluate the efficacy of Nd:YAG laser associated with calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion after erosive/abrasive challenges. METHODOLOGY: Dentin specimens were exposed to 17% ethylene diamine tetra-acetic acid (EDTA) solution for 5 min and randomly allocated into five groups: G1, control (no treatment); G2, Nd:YAG laser (1 W, 10 Hz, 100 mJ, 85 J/cm2); G3, Laser + TeethmateTM Desensitizer; G4, Laser + Desensibilize Nano P; and G5, Laser+Nupro®. Specimens underwent a 5-day erosion-abrasion cycling. Hydraulic conductance was measured post-EDTA, post-treatment, and post-cycling. Post-treatment and post-cycling permeability (%Lp) was calculated based on post-EDTA measurements, considered 100%. Open dentin tubules (ODT) were calculated at the abovementioned experimental moments using scanning electron microscopy and ImageJ software (n=10). Data were analyzed using two-way repeated measures ANOVA and Tukey's test (α=0.05). RESULTS: G1 presented the highest %Lp post-treatment of all groups (p<0.05), without significantly differences among them. At post-cycling, %Lp significantly decreased in G1, showed no significant differences from post-treatment in G3 and G4, and increased in G2 and G5, without significant differences from G1 (p>0.05). We found no significant differences in ODT among groups (p>0.05) post-EDTA. At post-treatment, treated groups did not differ from each other, but presented lower ODT than G1 (p<0.001). As for post-cycling, we verified no differences among groups (p>0.05), although ODT was significantly lower for all groups when compared to post-EDTA values (p<0.001). CONCLUSION: All treatments effectively reduced dentin permeability and promoted tubule occlusion after application. COMBINING ND: YAG laser with calcium-phosphate pastes did not improve the laser effect. After erosive-abrasive challenges, treatments presented no differences when compared to the control.

Association of Nd: YAG laser and calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion

Abstract Objective To evaluate the efficacy of Nd:YAG laser associated with calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion after erosive/abrasive challenges. Methodology Dentin specimens were exposed to 17% ethylene diamine tetra-acetic acid (EDTA) solution for 5 min and randomly allocated into five groups: G1, control (no treatment); G2, Nd:YAG laser (1 W, 10 Hz, 100 mJ, 85 J/cm2); G3, Laser + TeethmateTM Desensitizer; G4, Laser + Desensibilize Nano P; and G5, Laser+Nupro®. Specimens underwent a 5-day erosion-abrasion cycling. Hydraulic conductance was measured post-EDTA, post-treatment, and post-cycling. Post-treatment and post-cycling permeability (%Lp) was calculated based on post-EDTA measurements, considered 100%. Open dentin tubules (ODT) were calculated at the abovementioned experimental moments using scanning electron microscopy and ImageJ software (n=10). Data were analyzed using two-way repeated measures ANOVA and Tukey's test (α=0.05). Results G1 presented the highest %Lp post-treatment of all groups (p<0.05), without significantly differences among them. At post-cycling, %Lp significantly decreased in G1, showed no significant differences from post-treatment in G3 and G4, and increased in G2 and G5, without significant differences from G1 (p>0.05). We found no significant differences in ODT among groups (p>0.05) post-EDTA. At post-treatment, treated groups did not differ from each other, but presented lower ODT than G1 (p<0.001). As for post-cycling, we verified no differences among groups (p>0.05), although ODT was significantly lower for all groups when compared to post-EDTA values (p<0.001). Conclusion All treatments effectively reduced dentin permeability and promoted tubule occlusion after application. Combining Nd YAG laser with calcium-phosphate pastes did not improve the laser effect. After erosive-abrasive challenges, treatments presented no differences when compared to the control.

Is prolonged bleaching more harmful to dental enamel than daily dietary and hygienic oral habits?

Abstract The ultrastructural and mechanical properties of enamel surface were evaluated after prolonged bleaching treatments with 10% carbamide peroxide in the presence or absence of orange juice (erosive challenge) and toothbrushing (abrasive challenge). In total, 145 incisor bovine teeth were used in this study. Twenty-five samples were prepared for the ultrastructural evaluations, and 120 samples were prepared for microhardness and roughness tests. These 120 samples were divided into eight experimental groups (n = 15): G1- artificial saliva; G2- abrasion; G3- erosion; G4- dental bleaching; G5- erosion + abrasion; G6- bleaching + abrasion; G7- bleaching + erosion; and G8- bleaching + erosion + abrasion. All groups were tested at T0 (before treatment), T1 (14 days), T2 (21 days), and T3 (28 days). Two-way analysis of variance for repeated measures and the post hoc Sidak tests (p ≤ 0.05) were used. The roughness evaluation demonstrated an increase in damage for all experimental groups with an increase in the time period. For microhardness, the groups exposed to artificial saliva (AS) and abrasive challenge did not show any differences at any time points, while the other groups showed a decrease in microhardness from T0 to T3. Ultrastructural evaluation showed different surface alterations in response to the treatments. Despite prolonged bleaching periods, the procedure caused lesser enamel surface alterations than exposure to orange juice alone or in combination with brushing.

Enamel surface loss after erosive and abrasive cycling with different periods of immersion in human saliva.

OBJECTIVE: This in vitro study aimed to evaluate different periods of exposure to clarified human saliva for the ability to protect enamel against erosive tooth wear. METHODS: For this purpose, sixty specimens (4 × 4 × 1.5 mm) were prepared from third human molars. For all groups, the period before abrasion was performed by remineralisation with human saliva (except in G1). The specimens were randomly divided into six groups (n = 10) according to the different remineralisation times of exposure to clarified human saliva: no exposure to saliva (G1) and 30 min (G2), 60 min (G3), 90 min (G4), 120 min (G5), and 240 min (G6) of exposure to human saliva. A 5-day cycling was performed with 5 min of erosion (1% citric acid; pH 2.3), 4x/day. After the first and last erosive episodes, the abrasion challenge was performed with slurry of fluoride toothpaste (1450 ppm F-, as sodium monofluorophosphate) plus human saliva (1:3), with an electric toothbrush (15 s, with a total of 120 s of slurry immersion). Surface loss (SL) was determined using an optical profilometer (n = 10) and for qualitative analysis, environmental scanning electron microscopy (ESEM) was performed (n = 3). The SL data were statistically analysed by one-way analysis of variance (α = 0.05). RESULTS: No significant differences were detected among the groups for SL (p > 0.05), and ESEM showed similar aspects of eroded enamel. CONCLUSIONS: The period of in vitro exposure to clarified human saliva was not able to protect against enamel erosion.

Novel fluoride and stannous -functionalized ß-tricalcium phosphate nanoparticles for the management of dental erosion.

OBJECTIVE: To evaluate the anti-erosive effect of solutions containing ß-tricalcium phosphate (ß-TCP) nanoparticles functionalized with fluoride or with fluoride plus stannous on enamel and dentin. METHODS: ß-TCP nanoparticles were synthesized and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Sixty enamel and dentin specimens were randomly allocated into the groups (n = 10): Control (water); F (NaF, 225 ppm F-); F + Sn (NaF + SnCl2, 800 ppm Sn2+); F+ß-TCP (F+40 ppm ß-TCP); F + Sn+ß-TCP (F + Sn+40 ppm ß-TCP); F + Sn+100ß-TCP (F + Sn+100 ppm ß-TCP). Specimens underwent erosion-remineralization cycling (5 min immersion into 1 % citric acid solution and 60 min exposure to artificial saliva, 4×/day, 5 days). Immersion in the test solutions was performed for 2 min, 2×/day. Surface loss (SL, in µm) was determined by optical profilometry at the end of cycling. Data were analyzed using one way-ANOVA and Tukey's tests (α = 0.05). RESULTS: XRD confirmed the ß-TCP phase. TEM micrographs showed differences between the bare nanoparticle and the ß-TCP functionalized with F and Sn. All enamel groups presented lower SL than the control, with F + Sn, F + Sn+ß-TCP, and F + Sn+100ß-TCP showing the lowest values. For dentin, all the groups had lower SL than the control. F+ß-TCP presented the lowest SL, significantly differing from all the other groups. CONCLUSION: ß-TCP nanoparticles functionalized with fluoride showed improved anti-erosive effect compared to the fluoride solution on dentin. There was no significant effect of the ß-TCP nanoparticles functionalized with fluoride plus stannous in both substrates. CLINICAL RELEVANCE: ß-TCP nanoparticles are a promising agent to be added to oral health products to improve the protective effect of fluoride against dentin erosion.

Effect of in-office desensitizers containing calcium and phosphate on dentin permeability and tubule occlusion.

OBJECTIVES: To evaluate the performance of calcium/phosphate desensitizing agents when used for dentin permeability and tubule occlusion. METHODS: 1 mm-thick dentin specimens were immersed in 17% EDTA solution and allocated into 7 groups: 1. Clinpro White Varnish, 2. Clinpro XT Varnish, 3. Teethmate Desensitizer, 4. Desensibilize Nano P, 5. Nupro prophylaxis paste, 6. Duraphat (reference product), and 7. Control (no treatment). After treatment, specimens were submitted to erosion-abrasion cycling for 5 days. Dentin permeability was assessed by hydraulic conductance (n = 10) and environmental scanning electron microscopy ESEM (n = 8) post-EDTA, post- treatment and post-cycling. The percentage of permeability (%Lp) was calculated post-treatment and post-cycling. ImageJ software was used to obtain the number of open dentin tubules (ODT) in the micrographs. Data were statistically analyzed (α = 0.05). RESULTS: Post-treatment, the %Lp values of all treatments were significantly lower than the control, with Nupro presenting higher %Lp values than Duraphat. All the groups presented significantly lower %Lp values in the post-treatment in comparison with the post-cycling period, except the control. Post-treatment, all groups showed lower numbers of ODTs than the control, except Nupro. Clinpro WV, Clinpro XT, Duraphat and Nano P presented the best results. Post-cycling, there was no significant difference among groups. Clinpro WV and Duraphat presented lower numbers of ODTs post-treatment than they had post-cycling, and the control had a higher number of ODTs post-treatment than they had post-cycling. CONCLUSIONS: Most treatments were efficient in reducing both dentin permeability and number of ODTs after treatment; however, none of the products were able to resist the erosive-abrasive challenges.

Effect of Er,Cr:YSGG laser associated with fluoride on the control of enamel erosion progression.

OBJECTIVE: To evaluate the effect of Er,Cr:YSGG laser associated or not with acidulated phosphate fluoride (APF) on the control of enamel erosion progression. DESIGN: Enamel slabs (4 mm × 4 mm × 2 mm) from bovine incisors were flattened, polished, and received a tape on their test surfaces, leaving a 4 mm × 1 mm area exposed. Specimens were eroded (10 min in 1% citric acid solution) and randomly assigned into 8 experimental groups (n = 10): Control (no treatment); F (APF gel, 1.23% F, pH 3.6-3.9); Er,Cr:YSGG laser irradiation (P1: 0.25 W, 20 Hz, 2.8 J/cm2, 56 W/cm2); Er,Cr:YSGG laser irradiation (P2: 0.50 W, 20 Hz, 5.7 J/cm2, 1136 W/cm2); Er,Cr:YSGG laser irradiation (P3: 0.75 W, 20 Hz, 8.5 J/cm2, 1704 W/cm2); F + Laser P1; F + Laser P2; F + Laser P3. Specimens were then subjected to erosive cycling (5 min immersion in 0.3% citric acid solution, followed by immersion in artificial saliva for 60 min; 4×/day for 5 days). At the end of cycling, surface loss (SL, in µm) was determined with optical profilometry. Selected specimens were further evaluated by environmental scanning electron microscopy (n = 3). Data were analyzed using Kruskal-Wallis and Tukey tests (α = 0.05). RESULTS: Group F + Laser P2 had the lowest SL value, differing significantly from the control; however, with no significant difference from the other groups. All groups, except F + Laser P2, showed no significant difference in SL when compared with the control. An irregular and rough surface, suggestive of a melting action of laser, was observed on enamel in Laser P2 and F + Laser P2 groups. CONCLUSIONS: Association of the Er,Cr:YSGG laser in parameter 2 with fluoride was the only treatment capable of controlling the progression of enamel erosion.

Effectiveness and acid/tooth brushing resistance of in-office desensitizing treatments-A hydraulic conductance study.

OBJECTIVE: To evaluate dentin permeability and tubule occlusion of in-office desensitizing treatments, and to analyze their resistance to erosive/abrasive challenges. DESIGN: Ninety-one 1mm-thick dentin discs were immersed in EDTA solution for 5 min. After analyzing the maximum dentin permeability, the specimens were randomly allocated into 7 experimental groups (n = 10): Control (no treatment); Er,Cr:YSGG laser; Nd:YAG laser; Gluma Desensitizer; Duraphat; Pro-Argin toothpaste; Calcium Sodium Phosphosilicate (CSP) paste. The post-treatment permeability was assessed and then the specimens were subjected to a 5-day erosion-abrasion cycling protocol: 4x/day of immersion in citric acid solution (5 min;0.3%), followed by exposure to clarified human saliva (60 min). After the first and last acid challenges, specimens were brushed for 15 s, with exposure to the toothpaste slurry for total time of 2 min. Dentin permeability was re-measured (post-cycling). Percentage of dentin permeability for each experimental time was calculated in relation to the maximum permeability (%Lp). Data were analyzed with 2-way repeated measures ANOVA and Tukey tests (α = 0.05). Surface modifications were analyzed by scanning electron microscopy. RESULTS: In both experimental time CSP paste and Gluma Desensitizer did not differ from each other (p = 0.0874), and were the only groups that presented significantly lower %Lp than the Control (p = 0.026 and p = 0.022, respectively). After treatment, they were able to reduce dentin permeability in 82% and 72%, respectively. The %Lp post-cycling was higher than post-treatment value for all groups (p = 0.008). Dentin permeability increased 21% for CSP paste and 12% for Gluma, but they remained significant different from Control. Deposits on the surface were observed for CSP paste; and for Gluma, tubule diameters were shown to be smaller. CONCLUSIONS: CSP paste and Gluma Desensitizer were the only treatments able to decrease dentin permeability post-treatment and to sustain low permeability post-cycling.

Effect of desensitizing toothpastes on dentin erosive wear and tubule occlusion. An in situ study.

PURPOSE: To evaluate the effect of desensitizing dentifrices on dentin wear and tubule occlusion using a three-phase, single blind, crossover in situ trial. METHODS: The dentifrices containing Arginine and calcium carbonate (1,450 ppmF) and Novamin, (~1,426 ppmF) were tested in two conditions: A: abrasion and B: erosion/abrasion. A dentifrice without desensitizing agents was used as control (1,450 ppmF). In each study phase, 10 volunteers used intra-oral appliances containing dentin specimens (pre-treated with EDTA, to simulate hypersensitive dentin), which were either submitted to erosion with a cola-like drink (pH 2.6), 4×/day (2 minutes), followed by toothbrushing, using electric toothbrushes, with standard pressure (2×/ day, 5 seconds), or toothbrushing only. Dentin surface loss (SL, in µm) was determined with optical profilometry at the 3rd and 5th days of cycling. Dentin surface was analyzed with environmental scanning electron microscopy (ESEM), post EDTA and post cycling, and the dentin tubules were counted using Image J software. Data were statistically analyzed (α= 0.05). RESULTS: For condition A and B, there were no significant differences in SL among toothpastes in both experimental times. There were also no significant differences between times within groups. For ESEM, in A, Toothpaste with Novamin was the only dentifrice that showed significantly less opened tubules post cycling than post EDTA. In B, Toothpaste with Novamin and control toothpaste presented less opened tubules post cycling. In conclusion, toothbrushing with the tested dentifrices promoted similar levels of dentin loss; however, for tubule occlusion, the toothpaste with Novamin was the only toothpaste effective for both conditions, abrasion and erosion/abrasion. CLINICAL SIGNIFICANCE: Ideally, desensitizing dentifrices should promote obliteration of the dentin tubules or nerve desensitization, without further contributing to the progression of dentin wear.

The effect of desensitizing dentifrices on dentin wear and tubule occlusion.

PURPOSE: To evaluate the effect of desensitizing dentifrices on dentin erosive wear, using a 5-day erosion-abrasion-remineralization cycling model. The effect of the dentifrices on dentin's tubule occlusion was also investigated. METHODS: 30 samples of root dentin were randomly divided into three groups (n = 10): (1) Colgate Total 12 Clean Mint (control, 1,450 ppm F); (2) Colgate Sensitive Pro-Relief (1,450 ppm F, Pro-Argin); and (3) Sensodyne Repair&Protect (1,450 ppm F, Novamin). Erosion was performed with a cola drink, for 5 minutes, 4x/day. Toothbrushing with the slurry dentifrices (1:2) was performed 2x/day, with electric toothbrushes, using standard pressure for 15 seconds. Surface loss (SL) was determined with optical profilometry at baseline and after the first, third and fifth days of cycling. Before treatment and in the end of the cycling, the amount of opened dentin tubules per area was evaluated in three randomly selected specimens from each group, by environmental scanning electron microscopy. The relative dentin abrasitivity (RDA) of the dentifrices was also measured. Data were statistically analyzed (α = 0.05). RESULTS: All the dentifrices showed a progressive increase in SL over time. However, no significant differences in SL among the dentifrices were observed at any time studied. Sensodyne Repair&Protect significantly reduced the number of opened dentin tubules when compared to the other groups. Colgate Total 12 Clean Mint showed the highest RDA, followed by Sensodyne Repair&Protect and then by Colgate Sensitive Pro-Relief. The desensitizing dentifrices tested produced a similar rate of erosive dentin wear to the conventional dentifrice; however, only Sensodyne Repair&Protect was able to promote tubule occlusion.

Dental Adhesion to Erbium-Lased Tooth Structure: A Review of the Literature.

OBJECTIVE: The aim of the present study was to conduct a review of the literature about adhesion on erbium laser prepared cavities, related to the specific conditions of the irradiated dentin substrate and the effects on bond strength values. BACKGROUND DATA: Advances in adhesive restorative techniques significantly influenced modern restorative dentistry. The concept of "minimally invasive dentistry" aims to perform more conservative treatment of cavities in which the removal of sound dentin is no longer necessary. This approach, which relies on the concept of adhesion of restorative materials to the mineralized dental tissues, is considered to be a contemporary outcome in dentistry. Similarly, laser technology in restorative dentistry opened new possibilities and strategies as alternatives to conventional treatment. Considering the clinical aspects of the use of erbium lasers for caries removal, cavity preparations, and substrate conditioning, treatment with lasers can be considered to be an efficient technique with wide acceptance by patients. METHODS: Computerized and manual searches were conducted for studies through 2015 that addressed the topic. RESULTS: According to the literature, there is no defined standard protocol concerning the information that articles must provide, making a definitive protocol very difficult to establish. Data varied from the type of adhesive and resin composite used, substrate, and parameters (power, energy density, pulse duration, irradiation time, distance, cooling system) to the bond strength test methodology used. CONCLUSIONS: Further studies are necessary in order to define a standard protocol with positive results and higher bond strength values when using erbium lasers. Detailed information concerning laser parameters should be implemented. Also, longitudinal clinical studies should be developed in the search for new parameters that behave favorably in the irradiated substrate.

Benefits of laser phototherapy on nerve repair.

Post-traumatic nerve repair represents a major challenge to health sciences. Although there have been great advances in the last few years, it is still necessary to find methods that can effectively enhance nerve regeneration. Laser therapy has been widely investigated as a potential method for nerve repair. Therefore, in this article, a review of the existing literature was undertaken with regard to the effects of low-power laser irradiation on the regeneration of traumatically/surgically injured nerves. The articles were selected using either electronic search engines or manual tracing of the references cited in key papers. In electronic searches, we used the key words as "paresthesia", "laser therapy", "low-power laser and nerve repair", and "laser therapy and nerve repair", considering case reports and clinical studies. According to the findings of the literature, laser therapy accelerates and improves the regeneration of the affected nerve tissues, but there are many conflicting results about laser therapy. This can be attributed to several variables such as wavelength, radiation dose, and type of radiation. All the early in vivo studies assessed in this research were effective in restoring sensitivity. Although these results indicate a potential benefit of the use of lasers on nerve repair, further double-blind controlled clinical trials should be conducted in order to standardize protocols for clinical application.

Análise da perda de estrutura dentinária após desafio abrasivo com diferentes cremes dentais contendo agentes dessensibilizantes / Analysis of loss of dentine structure after challenge with different abrasive toothpastes containing desensitizing agents

Este estudo in vitro teve como objetivo avaliar a quantidade de perda de tecido dental após ciclos de erosão e abrasão com diferentes cremes dentais contendo ingredientes ativos para o tratamento da hipersensibilidade dentinária. Para tanto, quarenta amostras de dentina radicular (4x4x1,5 mm) foram confeccionadas a partir de terceiros molares humanos hígidos. Estes foram divididos aleatoriamente em 4 grupos (n=10): 1-controle negativo com água destilada, 2-controle positivo com Colgate Total 12, 3-Colgate Pró-Alivio e 4-Sensodyne Repair and Protect. Para o modelo de ciclagem erosiva foi utilizado o refrigerante Coca-Cola® por 5 minutos (4x/dia) a 37?C; e para a ciclagem abrasiva os espécimes foram submetidos a ciclos diários de escovação (2x/dia) com escova elétrica com pressão padronizada (15s). Os espécimes foram avaliados em Perfilometria óptica (n=10) e Microscopia Eletrônica de Varredura Ambiental (n=3) em duas fases distintas. Os dados de ambas as fases foram submetidos à análise estatística. Para a avaliação por perfilometria, a análise de variância ANOVA dois fatores para medidas repetidas mostrou que em todos os tratamentos a superfície dentinária foi afetada com o passar do tempo, havendo progressão da perda dentinária. Porém, não houve diferença estatística para cada tratamento realizado (p<0,05). Para avaliação em MEV, análises qualitativas e quantitativas foram realizadas. Para análise quantitativa, o teste Friedman demonstrou que os examinadores estavam calibrados

A análise de variância ANOVA mostrou que o Sensodyne Repair and Protect foi o creme dental mais eficaz na obliteração dos túbulos dentinários. Conclui-se que o desafio abrasivo combinado ao efeito erosivo apresenta-se como um potencial causador de lesões não cariosas e que os cremes dentais que contém dessensibilizantes apresentam comportamentos similares em termos de perda de substrato dentinário, quando comparados aos grupos controle, entretanto, mostram-se mais favoráveis para a oclusão tubular

This in vitro study had the main objective to evaluate the amount of dental tissue loss after erosion and abrasion cycles with different toothpastes with active ingredients for the treatment of dentin hypersensitivity. Forty samples of root dentin (4x4x1.5 mm) were prepared from human third molars and randomly divided into 4 groups (n=10): 1-negative control- distilled water, 2- positive control - Colgate Total 12, 3- Colgate Pro-Relief and 4- Sensodyne Repair and Protect. For the erosion model it was used Coca-Cola® for 5 minutes (4x/day). For the abrasion model, specimens were subjected to daily brushing cycles (2x/day) with electric toothbrush with standard pressure (15s). Specimens were evaluated in Optical Profilometry (n=10) and Electron Microscopy Environmental Scan (n=3) in two distinct phases. Data from both phases were analyzed statistically. For evaluation by profilometer examination, analysis of variance for repeated measures ANOVA showed that all treatments were affected in the course of time, with progression of dentin loss. However, there was no statistical difference among treatments (p <0.05). For SEM evaluation, qualitative and quantitative analyzes were performed. For quantitative analysis, Friedman test showed that the examiners were calibrated

The ANOVA showed that Sensodyne Repair and Protect was more effective in tubules obliteration. It can be concluded that the abrasive challenge combined with the erosive effect is presented as a potential cause of non-carious lesions and toothpastes containing desensitizing agents have similar behavior in terms of loss of dentin when compared to control groups. However, it showed more favorable results to tubular occlusion

Conditional factors for untreated caries in 12-year-old children in the city of São Paulo.

The aim of the study was to analyze what sociodemographic and economic variables were associated with the presence of untreated caries in 12-year-old children in the city of São Paulo. This cross-sectional study had a complex sample design. It was based on secondary data generated by the Levantamento epidemiológico em saúde bucal (Epidemiological Oral Health Survey) in the city of São Paulo, conducted in 2008, whose sample comprised 4,246 12-year-old children from the public and private schools of all the administrative districts of the city. A questionnaire was applied and an epidemiological exam was performed in accordance with the World Health Organization's (WHO) recommendations. The variables of interest were categorized into a dependent variable of untreated dental caries (carious component of the DMFT index that corresponds to carious, missing and filled teeth) and independent variables related to the socioeconomic and demographic conditions of the children and their families, and to their access to dental services. The EPI-INFO 06 and STATA 10 programs were used for the analysis; the prevalence ratio and a confidence interval of 95% were applied to the population parameters. The Poisson regression model was used, adjusted for sampling of the complex type. Caries was associated with ethnicity (higher rate in black people, p=0.042), attending public school (p=0.000), lower average family income (p=0.002), overcrowded dwellings (p=0.000) and presence of pain (p=0.000). Caries is a multifactorial disease influenced by social health determinants that intensify its risk.

Conditional factors for untreated caries in 12-year-old children in the city of Sao Paulo

The aim of the study was to analyze what sociodemographic and economic variables were associated with the presence of untreated caries in 12-year-old children in the city of São Paulo. This cross-sectional study had a complex sample design. It was based on secondary data generated by the Levantamento epidemiológico em saúde bucal (Epidemiological Oral Health Survey) in the city of São Paulo, conducted in 2008, whose sample comprised 4,246 12-year-old children from the public and private schools of all the administrative districts of the city. A questionnaire was applied and an epidemiological exam was performed in accordance with the World Health Organization's (WHO) recommendations. The variables of interest were categorized into a dependent variable of untreated dental caries (carious component of the DMFT index that corresponds to carious, missing and filled teeth) and independent variables related to the socioeconomic and demographic conditions of the children and their families, and to their access to dental services. The EPI-INFO 06 and STATA 10 programs were used for the analysis; the prevalence ratio and a confidence interval of 95% were applied to the population parameters. The Poisson regression model was used, adjusted for sampling of the complex type. Caries was associated with ethnicity (higher rate in black people, p = 0.042), attending public school (p = 0.000), lower average family income (p = 0.002), overcrowded dwellings (p = 0.000) and presence of pain (p = 0.000). Caries is a multifactorial disease influenced by social health determinants that intensify its risk.