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Streptococcus mutans is considered the primary etiologic agent of dental caries and contributes significantly to the virulence of dental plaque, especially in the presence of sucrose. To avoid the role of sucrose on the virulence factors of S. mutans, sugar substitutes are commonly consumed because they lead to lower or no production of acids and interfere with biofilm formation. This study aimed to investigate the contribution of sugar substitutes in the cariogenic potential of S. mutans biofilms. Thus, in the presence of sucrose, glucose, sucralose and sorbitol, the biofilm mass was quantified up to 96 h, the pH of the spent culture media was measured, the expression of biofilm-related genes was determined, and demineralization challenge experiments were conduct in enamel fragments. The presence of sugars or sugar substitutes profoundly affected the expression of spaP, gtfB, gtfC, gbpB, ftf, vicR and vicX in either biofilm or planktonic cells. The substitution of sucrose induced a down-regulation of most genes involved in sucrose-dependent colonization in biofilm cells. When the ratio between the expression of biofilm and planktonic cells was considered, most of those genes were down-regulated in biofilm cells in the presence of sugars and up-regulated in the presence of sugar substitutes. However, sucralose but not sorbitol fulfilled the purpose of reducing the cariogenic potential of the diet since it induced the biofilm formation with the lowest biomass, did not change the pH of the medium and led to the lowest lesion depth in the cariogenic challenge.

Dentine treatment with an Er,Cr:YSGG laser irradiation at a power of 0.5 W increased the BS of conventional GIC.

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<p><strong>Objective: </strong>Pulp calcification can compromise toothcolor and negatively affect esthetics. Definitivetreatment for discolored anterior teeth withcalcification is usually provided by endodontictreatment with the use of internal and externalbleaching agents, as necessary. This article presentsthe conservative management of a vital tooth withan obliterated pulp chamber that led to changes intooth color. The benefits and limitations of the use ofin-office and home supervised bleaching techniquesare discussed.</p><p>Keywords<br />Tooth bleaching; Dental pulp calcification.</p>

<p><strong>Objective</strong>: The aim of this study was to evaluate the adhesion of a self-etching system to caries-affected dentin (CAD) and sound dentin (SD) after different caries removal techniques by using microtensile bond strength test (μTBS). <strong>Materials</strong> <strong>and</strong> <strong>Methods</strong>: Twenty-four extracted human molars with coronal carious lesions were used. The samples were randomly divided into 5 groups, according to caries removal method: G1 - negative control (no removal); G2 abrasive disc; G3 – slow speed steel bur; G4 - Nd:YAG laser (energy density 21.2J/cm²); G5 - Er:YAG laser (energy density 80.24J/cm²). SD and  CAD/ infected dentin substrates were tested.  Self-etch system (Clearfil SE Bond) was applied and resin crowns were built up. <strong>Results</strong>: One-way ANOVA showed statistically significant difference between experimental groups (p&lt;0.001), with significantly lower results for infected dentin (G1), when compared to all other experimental groups. A statistically significant higher bond strength value was observed for SD irradiated with Er:YAG laser when compared to CAD. For bur and Nd:YAG laser specimens, SD and CAD showed the same bonding performance. <strong>Conclusion</strong>: infected dentin is not an adequate substrate for bonding; Nd:YAG laser and steel burs showed the same bonding performance for both SD and CAD; while both dentins, when irradiated by Er:YAG laser, did not adequately interact with self-etching system resulting in poor adhesion.</p><p><strong>Keywords</strong>: Er:YAG laser; Nd:YAG laser; Infected dentin; Dentin.</p>

Purpose This study investigated the long-term effect of Er:YAG laser pretreatment on the adhesion of a self-etch adhesive system to caries-affected dentin (CAD). Methods Ninety human dentin specimens were submitted to Streptococcus mutans biofilm cariogenic challenge (7 days) to obtain artificial CAD lesions (4 × 5 mm). Groups were defined by the surface pretreatment [no pretreatment; 80 mJ, 2 Hz, 50 μs, Results Three-way ANOVA and Tukey's multiple comparison tests (α = 0.05) showed that CAD had lower μSBS values than SD after 1 year despite surface pretreatments (p = 0.00). AL nanohardness test revealed that specimens' hardness decreased after 1 year (p = 0.00). The HL produced had lower nanohardness in CAD than in SD, which decreased over time for all surface pretreatments (p = 0.00). SEM analysis revealed that all adhesive interfaces, especially in CAD, degraded after 1 year. Conclusions Caries-affected dentin did not seem to be an adequate substrate for bonding. Er:YAG laser irradiation did not influence adhesion to CAD and SD.