Complicated crown fractures of maxillary anterior teeth caused by trauma in adolescence can cause functional and aesthetic problems. For crown fractures with pulp exposure, various restorative methods can be considered depending on the amount of remaining tooth structure. Direct resin restorations are the most traditional and effective method, but they are likely to discolor and break over time. Fixed prosthesis have a high possibility of re-restoration due to marginal disharmony due to tooth movement during the growth period, and restorations using post which are mainly performed for extensive crown fractures increase the risk of root perforation and root fracture. However, endocrown is an integrated structure that gains retention force from the pulp space, enabling effective reconstruction from a biomechanical perspective and providing advantages in restoring function and aesthetics.Therefore, endocrown can be considered as a restoration method for complicated crown fractures caused by trauma in adolescence.

Omnichroma (OMN) is a recently introduced structurally colored resin composite that expresses color based on the tooth structure surrounding the cavity. This study aims to investigate the effects of varying the cavity depth on the color blending of OMN.Conventional resin composite (Filtek Z250 in the A2, A3, and A4 shades) and structurally colored resin (Omnichroma) were used. Two types of specimens were prepared using custom silicone molds (diameter: 8 mm, thickness: 2, 3, 4 mm). Single specimens (diameter: 8 mm) comprised only Z250 in the A2, A3, A4 or OMN (n=10 each). Dual specimens comprised an outer ring (diameter : 8 mm) of Z250 in the A2, A3, or A4 and an inner hole (diameter: 4 mm) filled with OMN to different depths (1, 2, 3, or 4 mm, n=10 per shade per thickness). The colors were measuredusing the Commission Internationale d’Eclairage (CIE) L*a*b* system. Color differences (ΔE) according to the cavity depth and translucency parameter were measured.The ΔE values of dual specimens with the A2, A3, and A4 shades of Z250 were 1.66–5.07, 0.50–2.57, and 1.26– 3.48, respectively. At the same specimen thickness, ΔE increased with increasing cavity depth. At the same cavity depth, ΔE increased with decreasing thickness of the bottom of the restoration. The highest translucency parameterwas observed for 2 mm-thick OMN. The color blending of OMN increased with decreasing cavity depth in specimens of the same thickness, and with increasing bottom thickness of the restoration at the same cavity depth.

Universal adhesives that simplify bonding procedures and be used in multi-etch mode have been developed. In this study, the effects of agitation and solvent evaporation time of a universal adhesive on microtensile bond strength (µTBS) were evaluated by varying the times of these two procedures. Eighteen human molars were used to fabricate specimens, and the teeth were randomly divided into six experimental groups. Each group had different agitation time (5 s, 10 s, 20 s) and evaporation time (10 s, 20 s). The specimens were cut into a rod-shape with a cross-sectional area of 1 mm2 , and their µTBS was measured. The data were analyzed using an ANOVA and Tukey’s post hoc test. After this, the debonded surface was observed using scanning electron microscopy (SEM). In the groups with a solvent evaporation time of 20 s, µTBS was statistically higher, even with a short agitation time (p<0.05). Furthermore, for the groups with the shorter evaporation time, bonding strength decreased statistically as the agitation time shortened (p<0.05). The results of this experiment suggest that if the solvent was adequately evaporated, sufficient bonding strength could be obtained even when the adhesive was agitated for a short time. This is supported by the results of SEM image analysis, which revealed a uniform adhesive layer with well-infiltrated tags in the groups with the prolonged evaporation time. It may be crucial to secure an adequate evaporation time in order to obtain optimal bonding strength.

Universal adhesives that simplify bonding procedures and be used in multi-etch mode have been developed. In this study, the effects of agitation and solvent evaporation time of a universal adhesive on microtensile bond strength (µTBS) were evaluated by varying the times of these two procedures. Eighteen human molars were used to fabricate specimens, and the teeth were randomly divided into six experimental groups. Each group had different agitation time (5 s, 10 s, 20 s) and evaporation time (10 s, 20 s). The specimens were cut into a rod-shape with a cross-sectional area of 1 mm2 , and their µTBS was measured. The data were analyzed using an ANOVA and Tukey’s post hoc test. After this, the debonded surface was observed using scanning electron microscopy (SEM). In the groups with a solvent evaporation time of 20 s, µTBS was statistically higher, even with a short agitation time (p<0.05). Furthermore, for the groups with the shorter evaporation time, bonding strength decreased statistically as the agitation time shortened (p<0.05). The results of this experiment suggest that if the solvent was adequately evaporated, sufficient bonding strength could be obtained even when the adhesive was agitated for a short time. This is supported by the results of SEM image analysis, which revealed a uniform adhesive layer with well-infiltrated tags in the groups with the prolonged evaporation time. It may be crucial to secure an adequate evaporation time in order to obtain optimal bonding strength.

Dental trauma is very common in children and relatively young people, with the line of treatment depending on the time elapsed, age of the child, and tooth maturity. If the fractured segment is available and there is close approximation of the segment to the remaining tooth, reattachment of the fractured segment is a feasible option. This treatment offers several advantages, including the reestablishment of function, aesthetics, shape, shine and surface texture, in addition to the original contour and alignment of the teeth. The following cases present two different complex crown fracture cases that were treated using tooth fragment reattachment with fiber-reinforced composite post.

The purpose of this study was to evaluate the effects of deproteinization and an additional primer treatment on the microtensile bond strength of a newly developed self-adhesive resin cement to dentin. The occlusal dentin of extracted human third molars was randomly divided into four groups according to the surface treatment: a control (CON) with no treatment; applying a deproteinizing agent (DPT) (5% sodium hypochlorite); using a primer (PRI) (G-CEM ONE Adhesive enhancing primer, GC); and applying a deproteinizing agent and a primer (DPT-PRI). Composite resin blocks with a disk shape (diameter, 10 mm; height, 4 mm) were bonded to the treated dentin using a self-adhesive resin cement (G-CEM ONE, GC). The specimens were sectioned into sticks with a cross-section of 1 mm² and tested to failure in tension mode at a crosshead speed of 1 mm/min. All groups showed a significantly higher microtensile bond strength compared to CON (p<0.05). PRI showed the highest microtensile bond strength followed by DPT and DPT-PRI (p<0.05). No significant differences were observed between DPT and DPT-PRI (p>0.05). Within the limitations of this study, a deproteinizing agent or specific primer can enhance the microtensile bond strength of the self-adhesive resin cement to dentin. However, it is not recommended to use a primer in combination with the deproteinizing agents.
Adhesives ; Dentin ; Humans ; Molar, Third ; Resin Cements ; Sodium ; Sodium Hypochlorite

Crown fractures are the most frequent traumatic injuries to permanent teeth and mainly involve the maxillary incisors due to their exposed position in the dental arch. One option for managing crown fractures, when the tooth fragment is present and in good condition, is reattachment of the fragment to its original position. This paper reports on three crown fracture cases in which successful esthetic and functional results were achieved by reattachment of the tooth fragment.
Crowns ; Dental Arch ; Incisor ; Tooth

The purpose of this study was to evaluate the effect of different dentin surface treatments on the bond strength of self-adhesive resin cement (G-CEM one). Human permanent molars were sectioned horizontally and standard smear layer was created. Teeth were divided into 4 groups according to the treatment methods: 1) no treatment, 2) 10% polyacrylic acid treatment, 3) exclusive primer (G-CEM one primer) treatment, 4) polyacrylic acid + exclusive primer treatment. After surface treatment, composite resin blocks were cemented with G-CEM one. After storage, specimens were cut into bars to measure the microtensile bond strength. Measured data were statistically analyzed. Confocal laser scanning microscopy was used to observe the bonding interface of cemented surface. Polyacrylic acid surface treatment group showed significantly lower µTBS than other groups (p<0.05). µTBS of exclusive primer treated groups was significantly higher than the control group (p<0.05). As a result, the exclusive primer improved dentin-cement bond strength. Polyacrylic acid treatment alone had negative effect on µTBS of G-CEM one and dentin.

The purpose of this study was to examine effects of bioactive glass on Vickers hardness of bleached enamel surface. Enamel specimens were bleached with 15% carbamide peroxide (CP) for 14days. After bleaching, Artificial saliva (AS), 45S5 bioactive glass (BAG) and fluoride varnish (FV) are applied each specimens (n=10). The Vickers hardness of the specimens was measured before and after the bleaching, after the remineralized treatment at 1 day and after 7 and 14 days. The Vickers hardness on enamel surface after bleaching decreased statistically (p < 0.05) compared to before bleached enamel surface. The Vickers hardness increased significantly in the BAG and FV groups compared to the AS group values at 1 day and 7 days after remineralization (P < 0.05). 45S5 bioactive glass rapidly increase Vickers hardness of the bleached enamel surface.
Dental Enamel ; Fluorides ; Glass ; Hardness ; Paint ; Saliva, Artificial ; Urea

The purpose of this study is to evaluate the compatibility of universal adhesives with two dual-cured resin cements. Eighty human molars were divided into eight groups. Tooth was embedded in self-curing acrylic resin and sectioned horizontally to exposure dentine surface. After polishing with 600-grit SiC paper, adhesives were applied. All-Bond Universal (Bisco), G-premio bond (GC), Scotch-bond universal (3M ESPE), Scotch-bond Multipurpose (3M ESPE) were used in this study. Calibra (Dentsply) as a conventional dual-curing resin cement and RelyX Ultimate (3M ESPE) as an amine free resin cement were used. The adhesives and the cements were applied according to the manufacturer's instructions. Final specimens were cylinder (diameter 2mm, height 3mm) shape. After storing in distilled water at 37℃ for 7 days the shear bond strength (SBS) test was performed. There was no significant difference in shear bond strength between the adhesives when RelyX Ultimate was used (p>0.05). However, when Calibra used with Scotch-bond Multipurpose and All-Bond Universal were used, statistically higher SBS was observed, as compared to the groups which Calibra cements with G-premio bond and Scotch-bond universal adhesive (p < 0.05) were used. Within the limitations of this study, RelyX Ultimate resin cement was compatible with universal adhesives of various pH. All-Bond Universal adhesive was compatible with a resin cement containing the tertiary amine.
Adhesives ; Dentin ; Humans ; Hydrogen-Ion Concentration ; Molar ; Resin Cements ; Tooth ; Water