The concern with the polymerization shrinkage of restorative resin composites also applies to resin cements. The aim of this study was to evaluate the influence of volume and polymerization mode on forces generated during polymerization shrinkage (FGPS) of resin cements. Two light-cured resin cements--Variolink II (VL; Ivoclar Vivadent) and Nexus 3 (NX; Kerr)--and two self-cured resin cements - Multilink (ML; Ivoclar Vivadent) and Cement Post (CP; Angelus) - were inserted between two rectangular steel bases (6x2 mm) with distance set at 0.1, 0.3 and 0.5 mm, establishing a variation of volume. These steel bases were attached to a universal test machine with 50 kg load cell and forces (N) were registered for 10 min. Values of maximum forces generated by each material were subjected to two-way ANOVA and Tukey's test for individual comparisons (α=0.05). VL, NX and CP developed increasing FGPS as the volume of material increased, while ML presented the opposite behavior. It may be concluded that higher volume increases FGPS even with a concomitant decrease of C-factor, unless the resin cements present lower force generation rates as a function of time in combination with a low C-factor, resulting in stress relief and consequently lower values of FGPS.

Introduction: The use of a protective cervical barrier (PCB) is very well established to perform a safe internal bleaching; however, there is still no consensus on which material has the best sealing ability. Objective: This in vitro study aimed to evaluate the apical and linear sealing of different PCB materials placed during internal bleaching. Material and methods: This study had two study factors: PCB positioning, divided at two levels (cement-enamel junction [CEJ] Response variables were apical and linear sealing obtained through dye penetration and analyzed with a digital microscope. Data were subjected to two-way analysis of variance followed by Tukey test (p<0.05). Results: The main factor for both apical and linear sealing was the type of material (p<0.01), regardless of their position. RC and ZPC presented the worst sealing values (p<0.05). The Spearman

Increased surface roughness and wear of resin cements may cause failure of indirect restorations. The aim of this study was to evaluate quantitatively the surface roughness change and the vertical wear of four resin cements subjected to mechanical toothbrushing abrasion. Ten rectangular specimens (15 × 5 × 4 mm) were fabricated according to manufacturer instructions for each group (n = 10): Nexus 3, Kerr (NX3); RelyX ARC, 3M ESPE (ARC); RelyX U100, 3M ESPE (U100); and Variolink II, Ivoclar/Vivadent (VL2). Initial roughness (Ra, µm) was obtained through 5 readings with a roughness meter. Specimens were then subjected to toothbrushing abrasion (100,000 cycles), and further evaluation was conducted for final roughness. Vertical wear (µm) was quantified by 3 readings of the real profile between control and brushed surfaces. Data were subjected to analysis of variance, followed by Tukey's test (p < 0.05). The Pearson correlation test was performed between the surface roughness change and wear (p < 0.05). The mean values of initial/final roughness (Ra, µm)/wear (µm) were as follows: NX3 (0.078/0.127/23.175); ARC (0.086/0.246/20.263); U100 (0.296/0.589/16.952); and VL2 (0.313/0.512/22.876). Toothbrushing abrasion increased surface roughness and wear of all resin cements tested, although no correlation was found between those variables. Vertical wear was similar among groups; however, it was considered high and may lead to gap formation in indirect restorations.

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The use of a protective cervical barrier (PCB) is very well established to perform a safe internal bleaching; however, there is still no consensus on which material has the best sealing ability. Objective: This in vitro study aimed to evaluate the apical and linear sealing of different PCB materials placed during internal bleaching. Material and methods: This study had two study factors: PCB positioning, divided at two levels (cement-enamel junction [CEJ] and 1mm above the cement enamel junction [CEJ+1]); and PCB material, divided at eight levels (resin composite [RC], glass ionomer cement [GIC], resin-modified glass ionomer cement liner [LRGIC], restorative resin-modified glass ionomer cement [RRGIC], zinc phosphate cement [ZPC], eugenol-free zinc oxide cement [ZOC], provisional filling resin [PFR] and gutta-percha as control [GUT]). Response variables were apical and linear sealing obtained through dye penetration and analyzed with a digital microscope. Data were subjected to two-way analysis of variance followed by Tukey test (p<0.05). Results: The main factor for both apical and linear sealing was the type of material (p<0.01) regardless of their position. RC and ZPC presented the worst sealing values (p<0.05). The Spearman rank correlation coefficient revealed a positive correlation between the apical and linear leakage. Conclusion: The results suggest that RC and ZPC must be avoided as a PCB during internal bleaching procedures.

Cystinosis is a rare autosomal recessive lysosomal storage disorder, which leads to abnormal accumulation of cysteine in various organs, including progressive dysfunction of kidneys. The most severe and frequent form, affecting ∼95% of patients, is termed infantile nephropathic cystinosis (NC) (OMIM 219800). We have reported oral findings in two patients with NC and described esthetic and functional rehabilitation in one of them. The first case describes a 16‐year‐old male patient, who was diagnosed with NC when he was 1‐year‐old. The patient exhibited generalized enamel hypoplasia, grade 1 drug‐induced gingival overgrowth, caries lesion in molar tooth and supernumerary tooth (ie, distomolar). The second case describes a 14‐year‐old male patient diagnosed with NC at 3 years old. Clinical examination revealed generalized enamel hypoplasia and grade 1 drug‐induced gingival overgrowth. Radiographic examination showed supernumerary tooth (mesiodens). The treatment included gingivoplasty and restoration with direct composite resin. The severity of hypoplasia highlights the importance of a dental rehabilitation treatment, as proposed here. Direct restoration with composite resin allowed harmony, function, and esthetics to be restored, in addition to being a rapid and low‐cost technique.

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