Adhesive Restorations Research Articles

Barriers in Rubber Dam Isolation Behaviour of Dental Students During Adhesive Restorative Treatments: A Cross-Sectional Study.

There are unfavorable opinions connected with rubber dam isolation amongst dental students during adhesive restorative treatments. The aim of this study was to investigate the various barriers to practicing rubber dam isolation during dental procedures and provide necessary insight towards implementation of rubber dam among undergraduate dental students in Jazan. A pre-validated questionnaire in English entitled Rubber Dam Isolation Survey (E-RDIS) based on the Capability Opportunity Motivation-Behaviour (COM-B) model of behavioral change wheel was responded by 226 university dental students. The satisfaction of training was highest among sixth year students (Mean=3.57, p<0.001). Fourth year dental students scored higher in the capability (Mean=3.18) and were more highly motivated to use rubber dams (Mean=4.21). Third year students were more likely to use rubber dams in anterior teeth (Mean=3.52) whereas fourth year students use rubber dam in posterior teeth (Mean=3.74). Lack of motivation was found to be the significant barrier influencing rubber dam usage (odds ratio (OR)=12.1; 3.74, p<0.05). The satisfaction with training differed among the students of different years. The rubber dam technique might be used more frequently if it were made clear to students that mastering it would be necessary for them to receive good grades.

Comparative evaluation and patient satisfaction with an electrical impedance-based device versus digital radiography in the estimation of remaining dentin thickness in carious posterior permanent teeth: (Diagnostic accuracy study)

BackgroundAccurate assessment of remaining dentin thickness (RDT) is paramount for restorative decisions and treatment planning of vital teeth to avoid any pulpal injury. This diagnostic accuracy study compared the validity and patient satisfaction of an electrical impedance based device Prepometer™ (Hager & Werken, Duisburg, Germany) versus intraoral digital radiography for the estimation of remaining dentin thickness in carious posterior permanent teeth.MethodsSeventy patients aged 12–25 years with carious occlusal or proximal permanent vital posterior teeth were recruited. Tooth preparation was performed to receive an adhesive restoration. Pre- and post-excavation RDT were measured radiographically by two calibrated raters using the paralleling periapical technique. Prepometer™ measurements were performed by the operator. Patients rated their satisfaction level with each tool on a 4-point Likert scale and 100 mm visual analog scale (VAS). Inter and intragroup comparisons were analyzed using signed rank test, while agreement between devices and observations was tested using weight kappa (WK) coefficient.Resultsthe intergroup comparisons showed that, before and after excavation, there was a significant difference between measurements made by both techniques (p < 0.001). After excavation, there was a weak agreement between measurements (WK = 0.2, p < 0.001), whereas before excavation, the agreement was not statistically significant (p = 0.407). Patients were significantly more satisfied with Prepometer™ based on scales and VAS (p < 0.001).ConclusionPrepometer™ could be a viable clinical tool for determining RDT with high patient satisfaction, while radiographs tended to overestimate RDT in relation to the Prepometer™.

Comparative evaluation of bond strength of diode and neodymium-doped:Yttrium aluminum garnet-assisted bleached enamel with nanofilled composite: An in vitro study.

The world of esthetic dentistry is constantly making efforts toward the management of tooth staining. Laser-assisted bleaching is needed before adhesive restorations and has become common and advantageous as it accelerates bleaching action, reduces postoperative sensitivity, and promotes recrystallization of enamel. The study aimed to evaluate and compare the bond strength of diode (Biolace: EpicX) and neodymium-doped:yttrium aluminum garnet (Nd:YAG) (LightWalker, Fotona, Slovenia) assisted bleached (Pola Office, SDI) enamel with nanofilled composite (GC Solare Sculpt). The samples were divided into three groups (n = 11): Group A - Conventionally bleached enamel, Group B - Diode laser-assisted bleached enamel, Group C - Nd:YAG laser-assisted bleached enamel. After storing samples in Artificial Saliva for 2 weeks, bonding was performed, and nanofilled composite resin was applied through an incremental method. Samples were subjected to shear bond strength (SBS) analysis. The use of Nd:YAG laser on bleached enamel significantly increases the bond strength with nanofilled composite resin.

Warm Air Delivery in Adhesive Application: Effect on Bonding Performance and Morphological Outcomes.

Solvent evaporation within an adhesive layer is a crucial step during a bonding process. The aim of this current research was to test whether the use of different air temperatures (20 °C, 40 °C, and 60 °C) for solvent evaporation improves the performance of four adhesive systems to dentin. Sixty non-carious human molar teeth were randomly prepared for micro-tensile bond strength (μTBS) tests. Four different adhesive systems, Prime&Bond Universal (PBU), OptiBond Universal (OBU), OptiBond FL (OBFL), and Clearfil SE (CSE), were applied following the manufacturer's instructions. Three groups based on the air-drying temperature were used: solvent evaporation was performed with either of warm (40 °C), (60 °C), and cold air as control group (20 °C) for 10 s at a distance of 5 cm. In all bonded surfaces, three resin composite (Reflectys, Itena Clinical, Paris, France) layers of 2 mm thickness were built up. The resin-dentin samples were kept in distilled water at 37 °C for 24 h and 6 months, respectively, before μTBS testing. Failure analysis, scanning electron microscopy of resin-dentin bonded interface, and solvent evaporation rate were tested as secondary variables. All analyses were conducted using a significance level of α = 0.05. Bond strength (BS) values were similar among all the adhesive systems used (p > 0.05). Also, the aging factor did not affect the BS (p > 0.05). Only the factor of temperature used for solvent evaporation resulted in a statistically significant effect (p < 0.05), with the temperature of 60 °C being the highest value (p < 0.05). A failure mode evaluation revealed mostly adhesive or mixed modes of failures in all the different temperatures of air used for the solvent evaporation of each adhesive system. The thickness of the adhesive layer and the creation of resin tags varied amongst the temperatures evaluated. For all adhesive systems tested, the use of 40 °C or 60 °C air for solvent evaporation led to an increased mass loss. Warmer temperatures for solvent evaporation contributed positively to bonding performance, enhancing both the quality of the adhesive layer and its interaction with the dentin tissue. Optimizing solvent evaporation with warmer air temperatures (40 °C and 60 °C) significantly improved µTBS, offering a practical means to enhance the quality and longevity of adhesive restorations in esthetic dentistry.

Promoting bond durability by a novel fabricated bioactive dentin adhesive

ObjectiveTo prepare a bioactive dentin adhesive and investigate its effect on promoting bonding durability of dentin. MethodsThe mineralization of the bioactive glass with high phosphorus (10.8 mol% P2O5–54.2 mol% SiO2–35 mol% CaO, named PSC) and its ability to induce type I collagen mineralization were observed by SEM and TEM. The Control-Bond and the bioactive dentin adhesive containing 20 wt% PSC particles (PSC-Bond) were prepared, and their degree of conversion (DC), microtensile bond strength (μTBS), film thickness and mineralization performance were evaluated. To evaluate the bonding durability, dentin bonding samples were prepared by Control-Bond and PSC-Bond, and mineralizated in simulated body fluid for 24 h, 3 months, and 6 months. Then, the long-term bond strength and microleakage at the adhesive interface of dentin bonding samples were evaluated by microtensile testing and semiquantitative ELIASA respectively. ResultsThe PSC showed superior mineralization at 24 h and induced type I collagen mineralization to some extent under weakly alkaline conditions. For PSC-Bond, DC was 62.65 ± 1.20%, μTBS was 39.25 ± 4.24 MPa and film thickness was 17.00 ± 2.61 μm. PSC-Bond also formed hydroxyapatite and maintained good mineralization at the bonding interface. At 24 h, no significant differences in μTBS and interface microleakage were observed between the Control-Bond and PSC-Bond groups. After 6 months of aging, the μTBS was significantly higher and the interface microleakage was significantly lower of PSC-Bond group than those of Control-Bond group. SignificancePSC-Bond maintained bond strength stability and reduced interface microleakage to some extent, possibly reducing the occurrence of secondary caries, while maintaining long-term effectiveness of adhesive restorations.

Knowledge and precautions of light-curing composite resin restorations by dental students

Composite resin is versatile material for performing several dental procedures in dentistry, and its use has already been consolidated in this field. The clinical success of adhesive restorations is directly related to the knowledge of restorative material properties and light-curing unit factors, among others. The aim of the study was to assess the knowledge about the technical characteristics of light-curing devices and the forms of use and maintenance employed by undergraduate dental students. A total of 230 students answered a questionnaire containing six questions on technical data, use, and maintenance of light-curing units. Of the total number of participants, the majority were students from private educational institutions attending the last two years. With 59.1% of them unaware of the ideal irradiance of a light-curing unit, 73.0% were careful to position the light-curing unit as close as possible to the restoration, and 42.6% followed the light-curing time recommended by textbooks and theoretical texts. As for use and maintenance, 50.4% used the protector attached to the light-curing unit, 57.4% used safety barriers, and 63.0% sanitized the light tip after use. The evaluation suggests that student’s knowledge of “light-curing resin materials” is incomplete. Therefore, it can be inferred that the students have a good understanding of biosafety precautions when using light-curing units, but more knowledge is needed about the technical and clinical aspects of the devices.

Post-endodontic restoration: a direct or indirect restoration?

When restoring an endodontically treated tooth, it is important to preserve the pericervical dentin so it is resistant especially to lateral forces occurring during mastication. When little pericervical dentin is seen to be present, an adhesive restoration is indicated. Tooth survival of endodontically treated teeth restored with adhesive direct and indirect restorations varies between 90.5% and 95.0% after 5 years. Deciding between a direct or an indirect restoration depends above all on the possibility to predictably restore the anatomy and on gloss retention. Because endodontically treated teeth are vulnerable to lateral forces, control of these forces after direct or indirect restoration is important. This can be achieved by a reduction in the steepness of the cuspal slope and/or by covering the cusps with the restorative material.

Effect of the use of bromelain associated with bioactive glass-ceramic on dentin/adhesive interface.

To evaluate the effect of bromelain associated with Biosilicate on the bond strength (BS) of a universal adhesive system to sound (SD) and caries-affected dentin (CAD), and on the proteolytic activity. Cavities were prepared in 360 molars, half submitted to cariogenic challenge. Teeth were separated into groups (n=20): Control-No treatment; CHX-0.12% chlorhexidine; NaOCl-5% sodium hypochlorite; Br5%-5% bromelain; Br10%-10% bromelain; Bio-10% Biosilicate; NaOClBio-NaOCl+Bio; Br5%Bio-Br5%+Bio; Br10%Bio-Br10%+Bio. Following treatments, the adhesive system was applied, and cavities were restored. Samples were sectioned into sticks and stored at 37 °C for 24 h, 6 months, and 1 year. Microtensile BS (2-way ANOVA, Bonferroni's test, α=0.05), fracture patterns (SEM), and adhesive interfaces (TEM) were evaluated. Bacterial collagenase assay and in situ zymography were performed. In CAD, Br10% presented higher BS (p=0.0208) than Br5%Bio. Br5% presented higher BS (p=0.0033) after 6 months than after 24 h; and association of treatments, higher BS (p<0.05) after aging than after 24 h. Mixed fractures were the most prevalent. Association of treatments promoted a more uniform hybrid layer with embedded Bio particles. Experimental groups presented lower (p<0.0001) relative fluorescence units than Control. Bromelain, associated or not with Bio, showed collagenolytic degradation. Bromelain associated with Biosilicate did not affect the BS to SD. In CAD, Br5%Bio decreased immediate BS but had no long-term influence. This association decreased the proteolytic activity. Bromelain and Biosilicatemay enhance the longevity of adhesive restorations by inhibiting endogenous proteases.

Dentin adhesion of bulk-fill composites and universal adhesives in class I-cavities with high C-factor

ObjectivesThe aim of this study was to compare the dentin adhesion of bulk-fill composites in high C-factor class I-cavities before and after thermocycling to a control group using incremental layering technique. MethodsA standardized class I-cavity was prepared into 195 human molars, then different universal adhesives were applied either in self-etch or etch & rinse mode, and the cavity was filled according to each materials application protocol. The material combinations used were a conventional layered composite as control, the respective bulk-fill product, two other bulk-fill composites made by different manufacturers, with one of them being tested using two different polymerization times. Furthermore, one thermoviscous bulk-fill composite and one self-adhesive restorative were examined of which the latter can only be applied in self-etch mode. In each group the dentin adhesion to the cavity bottom was measured using microtensile bond strength test initially (24 h water storage) and after thermocycling. All results were statistically analyzed using STATA 17.0. ResultsThe statistical analysis showed significant differences between the control and the experimental groups (p < 0.001). The highest mean bond strength before (14.8 ± 10.7 MPa) and after aging (14.2 ± 11.5 MPa) was measured for the etch & rinse-control group. Among the bulk-fill groups, the etch & rinse technique consistently showed higher bond strengths. Bond strength of groups with shortened polymerization did not exceed 2.1 MPa. The bond strength of the self-adhesive restoration material was low before and after thermocycling (2.7 MPa/ 0.0 MPa). Groups with low bond strength values showed a high number of pre-testing-failures. ConclusionsBulk-fill materials used in high C-factor class I-cavities showed lower bond strength during self-etch application. The same applies for a shortened polymerization regime, which cannot be recommended for high C-factor cavities. Clinical significanceToday, a large variety of materials and application techniques can be used when placing an adhesive restoration. Whether new instead of established procedures should be applied in high C-factor cavities has to be critically assessed, as they are a demanding scenario for adhesive restorations.

Deep Margin Elevation - A Retrospective Clinical Study.

The aim of this retrospective study was to assess the short- to mid-term restorative and periodontal outcome of deep margin elevation (DME) performed using resin composite. Twenty-eight teeth treated with DME and indirect adhesive restorations were followed-up for a mean of 25.4 months (minimum: 12 months). Clinical and radiographic examination assessed the adaptation of the DME material and indirect restorations, presence of recurrent caries or discoloration, periodontal health at DME and non-DME sites, and periapical health. The overall success rate was 96.6%. One tooth showed signs and symptoms of apical pathology after 34 months following DME. No caries, discoloration, or periodontal pockets were detected in any of the treated teeth. DME had no detrimental effect on the gingival/periodontal health or plaque accumulation. There was no correlation between the distance from the DME material to the marginal bone level and pocket depth, gingival inflammation, and plaque accumulation (p > 0.05). Deep margin elevation might be considered a safe procedure for teeth with deep subgingival proximal caries in the short- and mid-term.

Comparative Evaluation of the Microleakage of Self-etch Adhesives on the Pulp Chamber Dentin after Proanthocyanidin Application: An In vitro Study

ABSTRACT Background: The long-term success of adhesive restorations is contingent on minimizing microleakage, which can lead to postoperative sensitivity and secondary caries. Sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) irrigation are commonly employed during adhesive restorative procedures, but their impact on microleakage remains a concern. Proanthocyanidin (PA), a naturally derived agent, has shown potential in enhancing bond strength. Aim: This study aimed to compare and evaluate the effect of treatment with or without 30% PA of the pulp chamber dentin after 1% NaOCl and 17% EDTA irrigation on the microleakage of adhesive restorations. Materials and Methods: Forty caries-free, freshly extracted permanent human molars were used. The pulp chamber roof was removed, and the roots were resected. Canal orifices were enlarged and sealed. Specimens were divided into four groups based on adhesives (OptiBond All-In-One and Adper Easy One) and irrigation regimens. After irrigation, pulp chambers were restored with Filtek Bulk-Fill composite resin. Microleakage was assessed using methylene blue dye penetration. Results: Microleakage was observed in all groups, irrespective of irrigation protocol and adhesives. PA application showed reduced dye penetration compared to without PA, although not statistically significant. Statistical analysis was performed using Kruskal–Wallis and Mann–Whitney tests at P &lt; 0.05. Conclusion: Irrigation protocols and the use of PA had no significant effect on the microleakage of self-etch adhesives to pulp chamber dentin. A 1-min application of 30% PA solution after NaOCl and EDTA irrigation did not improve the bonding of self-etch adhesives to pulp chamber dentin.

Uncommon Restoration on Nonvital Premolar with Porcelain Inlay: A Case Report with Five-year Follow-up

Introduction: In fixed prosthodontics, the old paradigm on endodontically treated teeth leads to more fragilization due to the architectural preparation needed for a full coverage crown. Endodontically treated premolars with class II defects are common in daily practice. When only one proximal surface is affected, direct adhesive restorations are the most used. The use of porcelain inlay is quite uncommon in this situation despite its advantages. Case Presentation: This article illustrates a clinical case of a 31-year-old female with healthy teeth except for the non-vital first maxillary premolar, presenting a class II mesio-occlusal cavity. The occlusion exam revealed functional anterior guidance and canine guidance on both sides during lateral mandibular translation. Based on mini-invasive dentistry principles, the decision was to restore the nonvital bicuspid with a porcelain inlay. Although scientific literature did not report restoration of the premolars with a ceramic inlay in clinical practice, this option was retained. The realization of a porcelain inlay was described step by step. A follow-up up to 5 years was done. Results: The iatrogenic tooth fragilization was avoided by a mini-invasive approach. At the end of this follow-up period, there was no complication or complaint. The patient was satisfied with the final result. Conclusion: Porcelain inlay seems to be a good option to restore the occluso-proximal cavity on nonvital premolars in a context of a favourable occlusion. Porcelain inlay is respectful of the principles of minimally invasive dentistry and allows to achieve the objectives of function, aesthetics and biocompatibility. However, clinical studies should be conducted to investigate the longevity of porcelain inlay on ETPs.

Performance of self-etching adhesives on caries-affected primary dentin treated with glutaraldehyde or silver diamine fluoride

Objectivesto evaluate the quality and stability of adhesive interfaces established by self-etching adhesives on caries-affected primary dentin (CAD) treated with glutaraldehyde (GA) or silver diamine fluoride (SDF). Methods42 primary molars were exposed to a microbiological caries-inducing protocol and divided into 6 groups according to the adhesive system (Clearfil SE - CL or FL Bond II - FL) and pretreatment (water, GA or SDF) applied on CAD. One tooth from each group was analyzed for surface modification using infrared spectroscopy. Crowns were restored with resin composite (n = 36) and cut into beams and slices. The beams were subjected to microtensile testing, Raman spectroscopy and SEM after 24 h and 6 months of storage. The slices were analyzed using Micro-Raman spectroscopy to determine the diffusion zone thickness (DZ) in each period. Data were analyzed by ANOVA and Tukey or Kruskal-Wallis and Dunn tests (α = 0.05%). ResultsSDF reduced the immediate bond strength for both adhesives. The control groups showed a decrease in BS after 6 months in artificial saliva. GA increased immediate DZ for FL, while SDF had the opposite effect on CL. GA decreased the DZ for FL at 6 months. There was a predominance of adhesive failures with areas of cohesive dentin fractures within control groups. SignificanceModifications caused by dentin surface treatments may directly affect the performance of adhesive systems and the quality and stability of adhesive restorations.

Enhancing dentin bonding quality through Acetone wet-bonding technique: a promising approach.

Objective: This paper aimed to assess the impact of the acetone wet-bonding (AWB) technique on dentin bonding and to investigate its potential underlying mechanisms. Materials and Methods: Caries-free third molars were sliced, ground, etched, water-rinsed. Then the specimens were randomly allocated to four groups according to the following pretreatments: 1. water wet-bonding (WWB); 2. ethanol wet-bonding (EWB); 3. 50% (v/v) acetone aqueous solution (50%AWB); 4. 100% acetone solution (AWB). Singlebond universal adhesive was then applied and composite buildups were constructed. The microtensile bond strength (MTBS), failure modes and interface nanoleakage were respectively evaluated after 24h of water storage, 10,000 times of thermocycling or 1-month collagenase ageing. In situ zymography and contact angle were also investigated. Results: Acetone pretreatment preserved MTBS after thermocycling or collagenase ageing (p < 0.05) without affecting the immediate MTBS (p > 0.05). Furthermore, AWB group manifested fewer nanoleakage than WWB group. More importantly, the contact angle of the dentin surfaces decreased significantly and collagenolytic activities within the hybrid layer were suppressed in AWB group. Conclusion: This study suggested that the AWB technique was effective in enhancing the dentin bond durability by increasing the wettability of dentin surface to dental adhesives, removing residual water in the hybrid layer, improving the penetration of adhesive monomer, and inhibiting the collagenolytic activities. Clinical significance: The lifespan of adhesive restorations would be increased by utilization of acetone wet-bonding technique.

Rapid Intrafibrillar Mineralization Strategy Enhances Adhesive–Dentin Interface

Biomimetic mineralization of dentin collagen appears to be a promising strategy to optimize dentin bonding durability. However, traditional postbonding mineralization strategies based on Ca/P ion release still have some drawbacks, such as being time-consuming, having a spatiotemporal mismatch, and having limited intrafibrillar minerals. To tackle these problems, a prebonding rapid intrafibrillar mineralization strategy was developed in the present study. Specifically, polyacrylic acid–stabilized amorphous calcium fluoride (PAA-ACF) was found to induce rapid intrafibrillar mineralization of the single-layer collagen model and dentin collagen at just 1 min and 10 min, as identified by transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. This strategy has also been identified to strengthen the mechanical properties of demineralized dentin within a clinically acceptable timeframe. Significantly, the bonding strength of the PAA-ACF–treated groups outperformed the control group irrespective of aging modes. In addition, the endogenous matrix metalloproteinases as well as exogenous bacterial erosion were inhibited, thus reducing the degradation of dentin collagen. High-quality integration of the hybrid layer and the underlying dentin was also demonstrated. On the basis of the present results, the concept of “prebonding rapid intrafibrillar mineralization” was proposed. This user-friendly scheme introduced PAA-ACF–based intrafibrillar mineralization into dentin bonding for the first time. As multifunctional primers, PAA-ACF precursors have the potential to shed new light on prolonging the service life of adhesive restorations, with promising significance.

Novel biomimetic peptide-loaded chitosan nanoparticles improve dentin bonding via promoting dentin remineralization and inhibiting endogenous matrix metalloproteinases

ObjectiveThis study aims to synthesize novel chitosan nanoparticles loaded with an amelogenin-derived peptide QP5 (TMC-QP5/NPs), investigate their remineralization capability and inhibitory effects on endogenous matrix metalloproteinases (MMPs), and evaluate the dentin bonding properties of remineralized dentin regulated by TMC-QP5/NPs. MethodsTMC-QP5/NPs were prepared by ionic crosslinking method and characterized by dynamic light scattering method, scanning electron microscopy, transmission electron microscope, atomic force microscope, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The encapsulation and loading efficiency of TMC-QP5/NPs and the release of QP5 were examined. To evaluate the remineralization capability of TMC-QP5/NPs, the mechanical properties, and the changes in structure and composition of differently conditioned dentin were characterized. The MMPs inhibitory effects of TMC-QP5/NPs were explored by MMP Activity Assay and in-situ zymography. The dentin bonding performance was detected by interfacial microleakage and microshear bond strength (μSBS). ResultsTMC-QP5/NPs were successfully synthesized, with uniform size, good stability and biosafety. The encapsulation and loading efficiency of TMC-QP5/NPs was respectively 69.63 ± 2.22% and 13.21 ± 0.73%, with a sustained release of QP5. TMC-QP5/NPs could induce mineral deposits on demineralized collagen fibers and partial occlusion of dentin tubules, and recover the surface microhardness of dentin, showing better remineralization effects than QP5. Besides, TMC-QP5/NPs significantly inhibited the endogenous MMPs activity. The remineralized dentin induced by TMC-QP5/NPs exhibited less interfacial microleakage and higher μSBS, greatly improved dentin bonding. SignificanceThis novel peptide-loaded chitosan nanoparticles improved resin-dentin bonding by promoting dentin remineralization and inactivating MMPs, suggesting a promising strategy for optimizing dentin adhesive restorations.

Effect of Sodium Ascorbate, Grape Seed Extract, and Aloe Vera Application after In-Office Bleaching on the Bond Strength of Enamel: A 3-Year Evaluation

Introduction. Dental bleaching is the first choice to improve smile esthetics, but, in some cases, it needs to be associated with resin composite restoration to obtain a satisfactory result. Unfortunately, the bonding of resin-based materials can be impaired due to residual oxygen molecules, which can decrease the durability of the restoration. Objectives. To evaluate the effect of the antioxidant application on the bond strength of bleached enamel after 24 hr and 3 years of water storage. Methods. In total, 84 bovine teeth were used in this study. Of these, 77 were bleached with 35% hydrogen peroxide in a single session for three cycles of 15 min. Then, the specimens were divided into groups (n = 7 each): control (without bleaching), without antioxidant (WA) use; application of 10% sodium ascorbate (SA) gel, grape seed (GS) extract, and aloe vera (AV). The restorative procedure was performed immediately after bleaching, 7 and 14 days after bleaching. Specimens were sectioned and evaluated using microtensile bond strength (μTBS). Half of the resin-enamel sticks were tested after 24 hr, and the remaining half after 3 years of water storage. µTBS data were analyzed using a three-way analysis of variance, Tukey’s test, and Dunnett’s test. Results. The lowest µTBS values were observed when the restoration was performed immediately after bleaching in the AV, GS, and WA groups when compared with the SA group ( p &lt; 0.005 ). However, no significant differences were observed among all groups after 3 years of water storage ( p &lt; 0.001 ). Conclusions. SA at 10% was the most effective antioxidant agent for improving the immediate bond strength. However, independent of the antioxidant agent used, the bond strength values were maintained or recovered after 3 years of water storage. SA at 10% could be used to avoid delayed bonding procedures after in-office whitening without compromising bond strength over time. Clinical Significance. The use of antioxidants after dental bleaching can be effective in improving the bonding durability of the adhesive restorations.

Effect of desensitizing agents on the resin bond strength to sound dentin.

This study aimed to evaluate the effect of dentin hypersensitivity treatments on immediate and long-term shear bond strength (SBS) of composite restorations. Ninety non-carious extracted human molars were cut to expose dentin, which was embedded in acrylic resin, and randomly divided into three groups (n = 30/group) according to surface treatment: 1) no treatment (C and C*; control); 2) silver diamine fluoride with potassium iodide (SDF/KI and SDF/KI*; Riva Star); and 3) nano-hydroxyapatite (nHAp and nHAp*; PrevDent). The specimens were etched through the etch-and-rinse technique, followed by universal adhesive application and resin composite cylinders (2.38mm in diameter × 3.5mm high). The SBS was tested immediately (24h after the restoration) and after thermocycling (*) (5000 cycles, 5°C to 55°C) at a 0.5mm/min crosshead speed using a universal testing machine. A stereomicroscope was used to evaluate the mode of failure, and representative scanning electron microscopy (SEM) images were also acquired. Data normality was verified, and two-way ANOVA and Tukey's post hoc tests were performed for multiple comparisons (α = 0.05). The control group presented the highest SBS (27.10MPa), while SDF/KI* had the lowest values (6.87MPa). nHAp-based desensitizer exhibited higher SBS than SDF/KI for both immediate (22.6MPa) and thermocycled (19.03MPa) conditions. No intragroup difference was evidenced between immediate and thermocycled samples for any group. Most specimens for the C and nHAp groups presented mixed failure, while the SDF/KI groups presented comparable adhesive and mixed failures. The SBS of adhesive restorations after the application of desensitizing agents is material dependent, where SDF/KI reduces SBS values below the acceptable minimum bond strength, while the nHAp application meets the minimally required bond strength.

Non-retentive adhesive restorations

With the advent of adhesive dentistry, tooth preparation can be minimally invasive. An optimal adhesion to the dental tissues is a requirement. Rubberdam isolation, using a gold standard adhesive and bonding to freshly prepared dentin are all factors that improve the adhesion to tooth tissue. For non-retentive restorations, indirect composite and glass-ceramic materials are suitable. To date, several studies have shown a high survival rate of indirect adhesive restorations. The adage "if you can isolate the tooth, you can preserve it" may guide the choice of starting an adhesive procedure.

Surgical extrusion, an alternative to a dental implant?

Unfortunately, accidents do happen. Dentoalveolar injury to the front teeth resulting from trauma can sometimes be so problematic that an (adhesive) restoration seems almost impossible to make, let alone saving the tooth. In this contribution the case of a 17-year-old patient whose upper incisor suffered severe dentoalveolar trauma in a traffic accident is presented. His upper incisor was fractured deeply subgingivally, at bone level, and at first glance, appeared to be lost. Surgical extrusion, however, in this patient represents a full alternative to a prosthetic solution, such as a dental implant.