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Teeth with altered size and shape, incisal wear, and inadequate position affect the smile and dentofacial harmony. The aim of this article was to describe a simple and safe protocol for an additive technique with composite resin and cosmetic enameloplasty to improve a patient's smile. A 24-year-old man complained about the appearance of his smile regarding color, shape, and position of the maxillary anterior teeth. Relevant dental history included previous orthodontic treatment with inadequate completion. The clinical examination revealed a disharmony of the smile caused by size and shape alterations of the incisors, a white spot on the right central incisor, incisal wear of the canines, and uneven incisal edges between the maxillary anterior teeth. Treatment with direct composite restoration and enameloplasty was performed in line with the current conservative approach in dentistry. The patient was recalled for 54 months. The use of appropriate techniques in enameloplasty allowed the desired outcome to be observed over the 54 months of follow-up. With this method, it is possible to perform future repair and/or modification, and it may increase the longevity of the restoration. Esthetic and functional results were achieved by careful planning and execution as well as periodic recalls. This conservative approach is a useful alternative to conventional restorations, reducing invasive treatments, chairside time, and costs. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the chemomechanical properties, antibacterial activity, and cytotoxicity of an experimental adhesive resin containing halloysite nanotubes (HNT), doped with alkyl trimethyl ammonium bromide (ATAB). Materials and Methods: A filler of HNT doped with ATAB was obtained (ATAB:HNT) and incorporated (5 wt%) into a resin blend made of bisphenol A glycerolate dimethacrylate, 2-hydroxyethyl methacrylate and a photoinitiator/co-initiator system (GATAB:HNT). The same resin blend without ATAB:HNT was used as control (Ctrl). The ATAB:HNT filler was assessed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The two tested adhesives were evaluated for degree of conversion (DC) in vitro and in situ, softening in alcohol, dentin microtensile bond strength (µTBS), antibacterial activity, and cytotoxicity (n = 5). Results: SEM showed that the nanotubes had a characteristic tubular-needle morphology, while the TEM analysis confirmed the presence of ATAB inside the lumens of HNT. The incorporation of ATAB:HNT induced no reduction (p > 0.05) of the DC either in situ or in vitro. No difference was encountered after the softening challenge test (p > 0.05) and no difference was found in µTBS between the two adhesives, both at 24 h (p > 0.05) and after 6 months of storage in distilled water (p > 0.05). However, ATAB:HNT reduced Streptococcus mutans viability (p < 0.05) without a cytotoxic effect on pulp cells (p > 0.05). Conclusions: GATAB:HNT adhesive demonstrated appropriate polymerization without significant differences in softening after solvent immersion, while concomitantly maintaining reliable bond strength after 6 months of water aging. Moreover, the ATAB:HNT filler can provide antibacterial activity to the adhesive resin without affecting pulp cell viability. [ABSTRACT FROM AUTHOR]

Purpose: To synthesize tantalum oxide quantum dots (Ta2O5QDs) using an imidazolium ionic liquid as a precursor and evaluate the effect of its addition to an experimental adhesive resin on the degree of conversion (DC) and antibacterial activity. Materials and Methods: Ta2O5QDs was synthesized from the hydrolysis of an imidazolium ionic liquid (1-n-decyl-3-methylimidazolium hexachlorotantalate [DMI.TaCl6]) and evaluated by transmission electron microscopy (TEM). The adhesive was formulated with 66.7 wt% bisphenol A-glycidyl methacrylate (bis-GMA), 33.3 wt% 2-hydroxyethyl methacrylate (HEMA) with a photoinitiator/co-initiator system. In one group, Ta2O5QDS was added to the adhesive at 1 wt% Ta2O5QDs) and one group remained without Ta2O5QDS as control (CTRL). The adhesives were evaluated for DC by Fourier Transform Infrared spectroscopy. Direct contact inhibition assay was used to evaluate the antibacterial activity of the experimental adhesive resins against biofilm formation and planktonic bacteria. Results: Ta2O5QDs had a particle size distribution of 1.52 ± 0.73 nm. DC was 50.91 ± 4.94% for CTRL and 55.4 ± 4.58% for Ta2O5QDs (p = 0.310). Ta2O5QDs showed less Streptococcus mutans biofilm formation on adhesive surfaces (p = 0.013). There was no statistically significant difference in terms of antibacterial activity against planktonic bacteria (p = 0.079). Conclusion: Non-agglomerated Ta2O5QDs synthesized from an imidazolium ionic liquid provided antibacterial activity to the experimental adhesive resin against biofilm formation of Streptococcus mutans. [ABSTRACT FROM AUTHOR]

PURPOSE. This study aimed to compare the microshear bond strength (µSBS) of dual-cure resin cement in CAD-CAM zirconia after different cleaning techniques. MATERIALS AND METHODS. Fifty discs of zirconia-based ceramic from Ivoclar Vivadent were embedded in acrylic resin. The discs were divided into five groups according to the cleaning methods used: Group 1: drying with spraying + sandblasting with Al2O3; Group 2: washed with water and dried with spraying + sandblasting with Al2O3; Group 3: washed with distilled water and dried with spraying + sandblasting with Al2O3 + zirconium oxide (Ivoclean); Group 4: washed with distilled water and dried with spraying + sandblasting with Al2O3 + potassium hydroxide (Zirclean); and Group 5: washed with distilled water and dried with spraying + sandblasting with Al2O3 + 1% NaClO. All of the groups were contaminated with artificial saliva for 1 minute and then cleaned. Statistical analyses were performed using ANOVA and Tukey's tests. RESULTS. There were statistically significant differences among all groups for µSBS (P < .05). The group treated with zirconium oxide (Group 3) showed the highest µSBS (18.75 ± 0.23 MPa). CONCLUSION. When applied to zirconia, the cleaning methods affected the bonding with resin cement differently. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the behavior of experimental dental adhesives with hydroxyapatite (HAp), alpha-tricalcium phosphate (α-TCP) or octacalcium phosphate (OCP) after storing them in three different media: dry storage, distilled water, or lactic acid. Methods: An experimental adhesive resin was formulated with bisphenol A glycol dimethacrylate, 2-hydroxyethyl methacrylate, and photoiniciator/co-initiator system. HAp (GHAp), α-TCP (Gα-TCP), or OCP (GOCP) were added to the adhesive resin at 2 wt.%, and one group remained without calcium phosphates to be used as a control (GCtrl). The adhesives were evaluated for surface roughness, scanning electron microscopy (SEM), and ultimate tensile strength (UTS) after storing in distilled water (pH=5.8), lactic acid (pH=4) or dry medium. Results: The initial surface roughness was not different among groups (p>0.05). GHAp showed increased values after immersion in water (p<0.05) or lactic acid (p<0.05). SEM analysis showed a surface variation of the filled adhesives, mainly for Gα-TCP and GHAp. GHAp showed the highest UTS in dry medium (p<0.05), and its value decreased after lactic acid storage (p<0.05). Conclusions: The findings of this study showed that HAp, OCP, and α-TCP affected the physical behavior of the experimental adhesive resins in different ways. HAp was the calcium phosphate that most adversely affected the surface roughness and the mechanical property of the material, mainly when exposed to an acid medium. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the influence of polyhexamethylene guanidine hydrochloride (PHMGH) in the physico- chemical properties and antibacterial activity of an experimental resin sealant. An experimental resin sealant was formulated with 60 wt.% of bisphenol A glycol dimethacrylate and 40 wt.% of triethylene glycol dimethacrylate with a photoinitiator/co-initiator system. PHMGH was added at 0.5 (G0.5%), 1 (G1%), and 2 (G2%) wt.% and one group remained without PHMGH, used as control (GCTRL). The resin sealants were analyzed for degree of conversion (DC), Knoop hardness (KHN), and softening in solvent (ΔKHN), ultimate tensile strength (UTS), contact angle (θ) with water or α-bromonaphthalene, surface free energy (SFE), and antibacterial activity against Streptococcus mutans for biofilm formation and planktonic bacteria. There was no significant difference for DC (p > 0.05). The initial Knoop hardness ranged from 17.30 (±0.50) to 19.50 (± 0.45), with lower value for GCTRL (p < 0.05). All groups presented lower KHN after immersion in solvent (p < 0.05). The ΔKHN ranged from 47.22 (± 4.30) to 57.22 (± 5.42)%, without significant difference (p > 0.05). The UTS ranged from 54.72 (± 11.05) MPa to 60.46 (± 6.50) MPa, with lower value for G2% (p < 0.05). PHMGH groups presented no significant difference compared to GCTRL in θ (p > 0.05). G2% showed no difference in SFE compared to GCTRL (p > 0.05). The groups with PHMGH presented antibacterial activity against biofilm and planktonic bacteria, with higher antibacterial activity for higher PHMGH incorporation (p < 0.05). PHMGH provided antibacterial activity for all resin sealant groups and the addition up to 1 wt.% showed reliable physico-chemical properties, maintaining the caries-protective effect of the resin sealant over time. [ABSTRACT FROM AUTHOR]

The process of bonding to dentin is complex and dynamic, greatly impacting the longevity of dental restorations. The tooth/dental material interface is degraded by bacterial acids, matrix metalloproteinases (MMPs), and hydrolysis. As a result, bonded dental restorations face reduced longevity due to adhesive interfacial breakdown, leading to leakage, tooth pain, recurrent caries, and costly restoration replacements. To address this issue, we synthesized and characterized a multifunctional magnetic platform, CHX@SiQuac@Fe 3 O 4 @m-SiO 2 , to provide several beneficial functions. The platform comprises Fe 3 O 4 microparticles and chlorhexidine (CHX) encapsulated within mesoporous silica, which was silanized by an antibacterial quaternary ammonium silane (SiQuac). This platform simultaneously targets bacterial inhibition, stability of the hybrid layer, and enhanced filler infiltration by magnetic motion. Comprehensive experiments include X-ray diffraction, FT-IR, VSM, EDS, N 2 adsorption-desorption (BET), transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, and UV-vis spectroscopy. Then, CHX@SiQuac@Fe 3 O 4 @m-SiO 2 was incorporated into an experimental adhesive resin for dental bonding restorations, followed by immediate and long-term antibacterial assessment, cytotoxicity evaluation, and mechanical and bonding performance. The results confirmed the multifunctional nature of CHX@SiQuac@Fe 3 O 4 @m-SiO 2 . This work outlined a roadmap for (1) designing and tuning an adhesive formulation containing the new platform CHX@SiQuac@Fe 3 O 4 @m-SiO 2 ; (2) assessing microtensile bond strength to dentin using a clinically relevant model of simulated hydrostatic pulpal pressure; and (3) investigating the antibacterial outcome performance of the particles when embedded into the formulated adhesives over time. The results showed that at 4 wt % of CHX@SiQuac@Fe 3 O 4 @m-SiO 2 -doped adhesive under the guided magnetic field, the bond strength increased by 28%. CHX@SiQuac@Fe 3 O 4 @m-SiO 2 enhanced dentin adhesion in the magnetic guide bonding process without altering adhesive properties or causing cytotoxicity. This finding presents a promising method for strengthening the tooth/dental material interface's stability and extending the bonded restorations' lifespan.