Resin Composite Build-ups Research Articles

Experimental use of an acrolein-based primer as collagen cross-linker for dentine bonding

ObjectivesThe objective of the present study was to investigate the long-term effect of 0.01% acrolein (ACR) aqueous solution, employed as an additional primer, on the mechanical durability and enzymatic activity of resin-dentine interfaces created with a simplified etch-and-rinse adhesive. MethodsDentine surfaces were etched with 35% phosphoric acid for 15s, rinsed and blot-dried. Specimens were then assigned to: Group 1: dentine pre-treated with 0.01% ACR aqueous solution for 1min and bonded with Adper Scotchbond 1 XT (SB1XT), a 2-step etch-and-rinse adhesive; Group 2: SB1XT was applied on untreated acid-etched dentine (control). Resin composite build-ups were made using Filtek Z250. Microtensile bond strength was tested by stressing sectioned specimens to failure immediately or after 1year of storage in artificial saliva at 37°C. Zymography and in-situ zymography assays were performed for examining dentine matrix metalloproteinase (MMP) activities. ResultsThe use of 0.01% ACR as conditioning primer appeared to have contributed better to preservation of bond strength over time without affecting immediate bond strength. Zymography and in-situ zymography showed reduction in MMP activities after the application of ACR. ConclusionDentine collagen cross-linking produced by an ACR-based primer increases the longevity of resin-dentine bonds by reinforcement of the adhesive interface and reduction of dentine MMP activities. Further studies are required to evaluate the potential in vivo and in vivo cytotoxicity of ACR. Clinical significanceThe acrolein-based primer is a potentially useful clinical bonding tool because it demonstrates good collagen cross-linking ability within a clinically-acceptable working time. Although a low ACR concentration was employed in the present study, the cytotoxicity of ACR should be tested prior to clinical use.

Comparative microtensile bond strength of universal adhesives in primary teeth

IntroductionAlmost 50 % of carious lesions in primary teeth remain untreated either due to limited compliance, or due to technique sensitivity of multi-step bonding systems or due to doubts about durability of resin composite restorations in primary teeth. Universal self-etch adhesives have been introduced in order to overcome the material- and technique-related problems because of their easy handling and their functional monomers, which have been reported to enhance bonding performance. Objective of the study was to compare 3 universal adhesives to a self-etch adhesive used as control.Material and methodsMid-coronal dentin was exposed in 20 primary molars, adhesives were applied followed by composite resin build-up: 1. Prime & Bond NT [PBNT] (control); 2. One Coat 7 Universal [OC7U]; 3. Futurabond U [FU]; 4. Prime & Bond active [PBA]. Beams were cut from specimen slabs and subjected to µ-tensile bond strength and mode of failure evaluation.ResultsFollowing bond strength values were re — corded (in MPa [SD]): PBNT (48.2 [14.3]), OC7U (69.7 [17]), FU (71.3 [17.7]), PBA (77.9 [23.5]). Sta — tistically significant differences were computed for all test groups compared to PBNT (p < 0.001, Bonferroni). PBA exhibited significantly higher values than OC7U (p < 0.05, Bonferroni). OC7U showed the lowest percentage of adhesive failures.ConclusionAll tested universal adhesives exhibited higher bond strength values in primary tooth dentin, in comparison to the traditional self-etch approach and can therefore be suggested as an alternative option in adhesive restorations in paediatric dentistry.

Mechanical and microbiological properties and drug release modeling of an etch-and-rinse adhesive containing copper nanoparticles

ObjectivesTo evaluate the effect of addition of copper nanoparticles (CN) at different concentrations into a two-step etch-and-rinse (2-ER) adhesive on antimicrobial activity (AMA), copper release (CR), ultimate tensile strength (UTS), degree of conversion (DC), water sorption (WS), solubility (SO), as well as the immediate (IM) and 1-year resin–dentin bond strength (μTBS) and nanoleakage (NL). MethodsSeven adhesives were formulated according to the addition of CN (0, 0.0075, 0.015, 0.06, 0.1, 0.5 and 1wt%) in adhesive. The AMA was evaluated against Streptococcus mutans using agar diffusion assay. For CR, WS and SO, specimens were constructed and tested for 28 days. For UTS, specimens were tested after 24h and 28 days. For DC, specimens were constructed and tested after 24h by FTIR. After enamel removal, the ER was applied to dentin. After composite resin build-ups, specimens were sectioned to obtain resin–dentin sticks. For μTBS and NL, specimens were tested after 24h and 1-year periods. All data were submitted to statistical analysis (α=0.05). ResultsThe addition of CN provided AMA to the adhesives at all concentrations. Higher CR was observed in adhesives with higher concentration of CN. UTS, DC, WS and SO were not influenced. For μTBS an increase was observed in 0.1 and 0.5% copper group. For NL, a significant decrease was observed in all groups in comparison with control group. After 1-year, no significant reductions of μTBS and no significant increases of NL were observed for copper containing adhesives compared to the control group. SignificanceThe addition of CN in concentrations up to 1wt% in the 2-ER adhesive may be an alternative to provide AMA and preserve the bonding to dentin, without reducing adhesives’ mechanical properties evaluated.

Effect of post-restoration on stresses in premolars with endodontic–periodontal lesion: an FEA study

Aim: This finite elemental stress analysis (FEA) study was aimed to test the effect of fiber and metal posts on stress distribution in premolar teeth with endodontic–periodontal (EP) lesion. Methodology: Three FEA models representing different EP lesions (primary endodontic disease (PED), PED with periodontal involvement and true-combined) were created. Tooth-model without EP lesion was used as control. The root-canals were assumed as root-filled, restored using glass-fiber or metal posts, resin composite build-up, and ceramic crown. A 300 N load was applied from the palatal surface of the crown with a 135° angle. The SolidWorks/Cosmosworks structural analysis program was used for FEA analysis. Results were presented by considering von Mises criteria. Results: Maximum stress values for PED, PED with periodontal-involvement and true-combined lesions were 2.26, 1.25, 0.74 MPa for glass-fiber post; 2.08, 1.51, 1.18 MPa for metal post, respectively. If there is PED, fiber-post gave an advantage to the tooth at core structure and coronal third of the root. Metal post kept the stress inside its body however caused small, high stress concentrated areas at cervical. When there is PED with periodontal-involvement, metal post forwarded less stress toward the apical while fiber-post saved the coronal structure. In true-combined lesion model, metal post kept the stresses within its body and forwarded less stress toward the remaining root structure and periodontium. Conclusion: EP lesions have an effect on stress distribution therefore the post material selection should be done based on the severity of the lesion. Metal posts might be preferrable since it forwards less stress toward the surrounding periodontal tissues during wound healing.

Effect of Non-Thermal Argon Plasma on Bond Strength of a Self-Etch Adhesive System to NaOCl-Treated Dentin.

Studies have been showing a decrease of bond strength in dentin treated with sodium hypochlorite (NaOCl). The aim of this study was to evaluate the effect of non-thermal argon plasma on the bond strength of a self-etch adhesive system to dentin exposed to NaOCl. Thirty-two flat dentin surfaces of bovine incisors were immersed in 2.5% NaOCl for 30 min to simulate the irrigation step during endodontic treatment. The specimens were divided into four groups (n=8), according to the surface treatment: Control (without plasma treatment), AR15 (argon plasma for 15 s), AR30 (argon plasma for 30 s) and AR45 (argon plasma for 45 s). For microtensile bond strength test, 5 specimens were used per group. In each group, the specimens were hybridized with a self-etch adhesive system (Clearfil SE Bond) and resin composite buildups were constructed. After 48 h of water storage, specimens were sectioned into sticks (5 per tooth, 25 per group) and subjected to microtensile bond strength test (μTBS) until failure, evaluating failure mode. Three specimens per group were analyzed under FTIR spectroscopy to verify the chemical modifications produced in dentin. μTBS data were analyzed using ANOVA and Tamhane tests (p<0.05). AR30 showed the highest μTBS (20.86±9.0). AR15 (13.81±6.4) and AR45 (11.51±6.8) were statistically similar to control (13.67±8.1). FTIR spectroscopy showed that argon plasma treatment produced chemical modifications in dentin. In conclusion, non-thermal argon plasma treatment for 30 s produced chemical changes in dentin and improved the μTBs of Clearfil SE Bond to NaOCl-treated dentin.

Effect of HEMA Phosphate as an Alternative to Phosphoric Acid for Dentin Treatment Prior to Hybridization with Etch-and-Rinse Adhesive Systems.

To evaluate the effect of dentin treatment using HEMA phosphate (HEMA-P) on the microtensile bond strength (μTBS) and nanoleakage of an etch-and-rinse adhesive system. The occlusal surfaces of human molars were wet ground until superficial dentin was exposed. The specimens were then assigned to two groups according to dentin treatment: PA: 37% H₃PO₄ for 15 s; or HP: HEMA-P for 15 s. Adper Single Bond 2 was applied to the treated dentin surfaces and resin composite buildups were incrementally constructed over them. After 24-h storage in artificial saliva at 37°C, the bonded teeth were cut into resin-dentin sticks with a cross-sectional area of 1 mm², which were submitted to μTBS testing immediately or after 3 months of storage in artificial saliva at 37°C. Nanoleakage was assessed using SEM/EDS, and the interaction between dentin and H₃PO₄ or HEMA-P was evaluated by combining micro-Raman and FT-IR spectroscopy. The data were analyzed using two-way ANOVA and Tukey's HSD post-hoc test (α = 0.05). HP presented significantly higher μTBS than PA at both times (p < 0.05). Both treatments maintained μTBS stability after 3 months of artificial saliva storage (p > 0.005). At both times, PA presented higher nanoleakage than HP (p < 0.05). Both dentin treatments maintained μTBS stability after 3 months of artificial saliva storage. The use of HEMA-P was associated with less nanoleakage than was traditional phosphoric-acid etching.

Resin-dentin Bond Stability of Experimental 4-META-based Etch-and-rinse Adhesives Solvated by Ethanol or Acetone.

To investigate the influence of 4-META concentration and type of solvent on the degree of conversion (DC%) and resin-dentin bond stability of experimental etch-and-rinse adhesives. Four different concentrations of 4-META (12 wt%, 20 wt%, 30 wt%, 40 wt%) were added to a model adhesive system consisting of TEG-DMA (25 wt%), UDMA (20 wt%), HEMA (30 wt%), water (4 wt%), camphorquinone (0.5 wt%), and tertiary amine (0.5 wt%) dissolved in 20% acetone (A12, A20, A30 and A40) or 20% ethanol (E12, E20, E30 and E40). DC% was evaluated by FT-IR spectroscopy. Human molars were wet ground until the occlusal dentin was exposed, the adhesive systems were applied after 37% phosphoric acid etching, and resin composite buildups were incrementally constructed. After storage in distilled water at 37°C for 24 h, the teeth were cut into resin-dentin beams (cross-sectional area 1 mm2). Microtensile bond strength (μTBS) was evaluated after 24 h, 6 months, and 1 year of water storage at 37°C. The failure mode was categorized as adhesive, mixed, or cohesive. Data were analyzed using ANOVA and Tukey's HSD test (α = 0.05). A12 presented the lowest DC% (p < 0.05). All the other adhesive systems showed statistically similar DC% (p > 0.05). All adhesive systems maintained resin-dentin bond stability after 6 months of water storage, while only A40 and E40 maintained it after 1 year. Irrespective of the type of organic solvent, the incorporation of high concentrations of 4-META (40 wt%) improved the resin-dentin bond stability of the experimental etch-and-rinse adhesive systems over a period of 1 year.

Resin bond strength to water versus ethanol-saturated human dentin pretreated with three different cross-linking agents.

Context:Resin-dentin bonds are unstable owing to hydrolytic and enzymatic degradation. Several approaches such as collagen cross-linking and ethanol-wet bonding (EWB) have been developed to overcome this problem. Collagen cross-linking improves the intrinsic properties of the collagen matrix. However, it leaves a water-rich collagen matrix with incomplete resin infiltration making it susceptible to fatigue degradation. Since EWB is expected to overcome the drawbacks of water-wet bonding (WWB), a combination of collagen cross-linking with EWB was tested.Aim:The aim of this study was to compare the effect of pretreatment with different cross-linking agents such as ultraviolet A (UVA)-activated 0.1% riboflavin, 1 M carbodiimide, and 6.5 wt% proanthocyanidin on the immediate and long-term bond strengths of an etch and rinse adhesive system to water- versus ethanol-saturated dentin within clinically relevant application time periods.Settings and Design:Long-term in vitro study evaluating the microtensile bond strength of adhesive-dentin interface after different surface pretreatments.Subjects and Methods:Eighty freshly extracted human molars were prepared to expose dentin, etched with 37% phosphoric acid for 15 s rinsed, and grouped randomly. They were blot-dried and pretreated with different cross-linkers: 0.1% riboflavin for 2 min followed by UVA activation for 2 min; 1 M carbodiimide for 2 min; 6.5 wt% proanthocyanidin for 2 min and rinsed. They were then bonded with Adper Single Bond Adhesive (3M ESPE), by either WWB or EWB, followed by resin composite build-ups (Filtek Z350, 3M ESPE). Bonded specimens in each group were then sectioned and divided into two halves. Microtensile bond strength was tested in one half after 24 h and the other after 6 months storage in artificial saliva.Statistical Analysis Used:Analysis was done using SPSS version 18 software (SPSS Inc., Chicago, IL, USA). Intergroup comparison of bond strength was done using ANOVA with post hoc Tukey's test, and intragroup comparison was done using paired t-test.Results:The microtensile bond strength of cross-linked groups was higher compared to control group (P < 0.001). EWB showed much higher bond strength values on cross-linked dentin compared to noncross-linked dentin. UVA-activated riboflavin group exhibited highest bond strengths followed by carbodiimide and proanthocyanidin groups, respectively, on both water- as well as ethanol-saturated dentin. Even after 6 months storage, cross-linked groups showed significantly higher values compared to initial bond strength values of control group (P < 0.001).Conclusions:0.1% riboflavin pretreatment of dentin followed by UVA activation for 2 min exhibited highest increase in bond strength values at 24 h and least reduction in bond strength values after 6 months storage compared to other groups. Biomodification of dentin using collagen cross-linking followed by EWB exhibited a synergistic effect in improving the resin-dentin bond durability.

Aesthetic closure of maxillary and mandibular anterior spaces using direct composite resin build-ups: A case report

The presence of multiple spaces in the anterior aesthetic zone can produce discomfort for patients and its treatment can be difficult for dental professionals. A variety of treatment options are available and these include orthodontic movement, prosthetic indirect restorations or direct composite resin build-ups. Among these, the closure of interdental spaces using composite build-ups combined with orthodontic treatment is considered to be most conservative. This type of treatment has several advantages like the maximum preservation of tooth substance (no tooth preparation), no need for anesthesia, no multiple time-consuming visits, no provisional restorations and also comparably low costs. Clinical Consideration: This case report describes the clinical restorative procedure of direct composite resin build-ups for the closure of multiple anterior spaces.

Agreement Among Dental Students, Peer Assessors, and Tutor in Assessing Students’ Competence in Preclinical Skills

The aim of this study was to determine the level of agreement regarding assessments of competence among dental students, their student peers, and their clinical skills tutors in a preclinical skills program. In 2012-13 at the University of Edinburgh, second-year dental students learned to perform the following seven cavity preparations/restorations on primary and permanent Frasaco teeth: single-surface adhesive occlusal cavity; single-surface adhesive interproximal cavity; single-surface adhesive labial cavity; multi-surface adhesive cavity; multi-surface amalgam cavity; pre-formed metal crown preparation; and composite resin buildup of a fractured maxillary central incisor tooth. Each student, a randomly allocated student peer, and the clinical skills tutor used standardized descriptors to assign a competency grade to all the students' preparations/restorations. The grades were analyzed by chi-square analysis. Data were available for all 59 second-year students in the program. The results showed that both the students and their peers overestimated the students' competence compared to the tutor at the following levels: single-surface adhesive occlusal cavity (χ(2)=10.63, p=0.005); single-surface adhesive interproximal cavity (χ(2)=11.40, p=0.003); single-surface labial cavity (χ(2)=23.70, p=0.001); multi-surface adhesive cavity (χ(2)=12.56, p=0.002); multi-surface amalgam cavity (χ(2)=38.85, p=0.001); pre-formed metal crown preparation (χ(2)=40.41, p=0.001); and composite resin buildup (χ(2)=57.31, p=0.001). As expected, the lowest levels of agreement occurred on the most complicated procedures. These findings support the need for additional ways to help students better self-assess their work.

Experimental etch-and-rinse adhesive systems containing MMP-inhibitors: Physicochemical characterization and resin-dentin bonding stability

ObjectivesTo evaluate the degree of conversion (DC%), water sorption (WS), solubility (SO) and the resin–dentin bonding stability (μTBS) of experimental (EXP) etch-and-rinse adhesive systems containing MMP-inhibitors: Galardin-GAL, Batimastat-BAT, GM1489-GM1 and chlorhexidine diacetate-CHX. MethodsDC% was measured using FT-IR spectroscopy, while WS and SO were calculated based on ISO4049. Thirty-six human molars were wet ground until the occlusal dentin was exposed. The adhesive systems were applied and resin composite buildups were incrementally constructed. After 24h immersion in distilled water at 37°C, the specimens were cut into resin-dentin beams with a cross-sectional area of 1mm2. The μTBS was evaluated after 24h, 6 months and 12 months of water storage at 37°C. Adper Single Bond 2 (SB2) was used as a commercial control. The data were analyzed using ANOVA and Tukey’s HSD test. ResultsSB2 presented the highest DC% (p<0.05). CHX presented the lowest WS (p<0.05). GM1, GAL and BAT presented similar WS when compared with SB2 (p>0.05). SO was found to be not significant (p>0.05). All adhesive systems maintained μTBS stability after 6 months of water storage. Only BAT, GM1 and CHX maintained μTBs stability after 12 months of water storage. ConclusionsThe experimental adhesive systems with GM1489 and chlorhexidine diacetate presented the best physicochemical properties and preserved resin–dentin bonding stability after 12 months of water storage. Clinical significanceGM1489 could be suitable for inclusion as an MMP-inhibitor in etch-and-rinse adhesive systems to maintain resin-dentin bonding stability over time.

CAD/CAM Polymer vs Direct Composite Resin Core Buildups for Endodontically Treated Molars Without Ferrule.

The aim of this study was to investigate the restoration of broken-down endodontically treated molars without ferrule effect using glass ceramic crowns on different composite resin core buildups. Forty-five decoronated endodontically treated teeth (no ferrule) were restored with a semidirect buildup using an experimental computer-aided design/computer-aided manufacturing (CAD/CAM) high-performance polymer (HPP group) or with light-curing composite core buildups of Tetric EvoCeram with (TECP group) or without (TEC group) a glass-fiber-reinforced post. All teeth were prepared to receive bonded glass ceramic crowns (Empress CAD luted with Variolink II) and were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the palatal cusp at an angle of 30° and a frequency of 5 Hz, beginning with a load of 200 N (×5000 cycles) and followed by stages of 400, 600, 800, 1000, 1200, and 1400 N at a maximum of 30,000 cycles each. Specimens were loaded until failure or to a maximum of 185,000 cycles. Groups were compared using the life-table survival analysis (log rank test at p=0.05). Average fracture loads and number of survived cycles were compared with one-way analysis of variance (Scheffé post hoc at p=0.05). None of the tested specimen withstood all 185,000 load cycles. There was a significant difference in mean fracture load, survived cycles, and survival; the HPP group (fracture load 975.27N±182.74) was significantly higher than the TEC (716.87N±133.43; p=0.001) and TECP (745.67±156.34; p=0.001) groups, and the TEC and TECP groups showed no difference (p=0.884). Specimens in the TECP group were affected by an initial failure phenomenon (wide gap at the margin between the buildup/crown assembly and the root). Semidirect core buildup made from high-performance polymer enhanced the performance of all-ceramic leucite-reinforced glass ceramic crowns compared with direct light-curing composite resin buildups. The use of a fiber-reinforced post system did not influence the fatigue strength of all-ceramic crowns.

A 6.5-year clinical follow-up of direct resin composite buildups in the posterior dentition: Introduction of a new minimally invasive restorative method

ObjectivesRestorative rehabilitation of missing single teeth in the posterior dentition is achieved primarily by dental implants or fixed dental prostheses. Here we introduce an uncommon, minimally invasive treatment option in order to close single tooth gaps. MethodsThe purpose of this study was to evaluate the clinical quality and survival of 45 direct composite buildups in the posterior dentition. A detailed clinical examination was performed, and restorations were rated qualitatively using the modified USPHS/FDI criteria. ResultsThe mean extension of the direct composite buildups was 2.96 (1.12)mm per tooth. Interdental closures from both adjacent teeth had a significantly higher extension of the direct composite buildups than one-sided interdental closures (p=0.03). Patients with a history of prior tooth loss showed a significantly greater extension of direct composite buildups than patients without prior tooth loss (p=0.006). During the follow-up period, no restoration showed unfavorable events. The overall survival rate for the direct composite buildups was 100% after median follow-up of 78.96 months. The clinical quality rating indicated that most of the restorations (>94%) displayed excellent or good quality. No periodontal destruction, signs of gingival inflammation or increased plaque accumulation was observed. ConclusionsThe posterior direct composite buildups evaluated in this study showed promising clinical survival data and excellent quality parameters after a median observation time of 6.5 years. Clinical SignificanceIf a minimally or non-invasive treatment approach is indicated, posterior direct composite buildups provide a successful treatment alternative for the closure of single-tooth gaps to implant-supported or fixed dental prostheses.

Resin composite build-ups for complementing multidisciplinary esthetic and functional dental treatments: a case report

Discrepancies in tooth shape and placement of the anterior teeth represent uncomfortable esthetic scenario for many patients. Even current composite resin proximal build-up is considered to be practical and conservative, in some cases, interdisciplinary approach with orthodontics optimize functional and esthetic results. This case report describes the management of a patient who complained of lack of anterior esthetic, which compromises her quality of life. The correct diagnosis and the treatment with interdisciplinary strategy are highlighted to offer a reliable and promissory treatment.Keywords: Composite resin; Diastema closure; Orthodontics

Bond strength of etch-and-rinse adhesive systems to plasma-treated dentin

Purpose: The aim of this study was to determine the influence of atmospheric pressure plasma (APP) treatment and water storage onmicrotensile dentin bond strength (BS) of two adhesive systems. Methods and materials: Twenty-eight third human molar were sectioned to remove the enamel occlusal surface and grounded (600-grit SiC) to expose a flat dentin surface. Teeth were randomly divided into four groups (n=7), following the application or not of APP for 30 s after etchingwith phosphoric acid and two adhesives (XP Bond, Dentsply and Optibond FL, Kerr). After the composite resin build-up, teethwere sectioned perpendicular to the bonded interface to obtain beams specimens. The specimens were tested after 24h and one year of water storage until failure. Bond strength data were analyzed by three-way ANOVA and Tukey post-hoc test (a=0.05). Results: BSmeans for XP Bondwere (inMPa): Control (24h): 45.1± 4.6; Control (1 year): 42.2± 3.4, APP (24h): 59.0± 10.2; APP (1 year): 47.1± 13.2 and BS means for Optibond FL were: Control (24h): 68.3± 7.7; Control (1 year): 56.4± 6.7, APP (24h): 57.4± 13.7; APP (1 year): 53.5± 10.9. Conclusion:APP application decreased the BS for Optibond FL, while for XP Bond the BS increased. However, this increasing was not stable after one year of water storage. The effects of APP and long-term storage on dentin BS were productdependent.

The Simultaneous Effect of Extended Etching Time and Casein Phosphopeptide-Amorphous Calcium Phosphate containing Paste Application on Shear Bond Strength of Etch-and-rinse Adhesive to Caries-affected Dentin.

This study evaluated the simultaneous effect of extended etching time and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) containing paste application on shear bond strength (SBS) of etch-and-rinse adhesive to caries-affected-dentin (CAD). Fifty human third molars were used; 10 normal in group 1 and 40 caries-affected teeth in groups 2 to 5. In the CAD groups, teeth were randomly assigned into four groups (n = 10). In groups 2 and 4, phosphoric acid etching for 15 and 45 seconds was used and in groups 3 and 5, after 15 or 45 seconds etching respectively, CPP-ACP containing paste (MI paste) was applied for 3 minutes. After rinsing, single bond adhesive system and Z250 composite were used for resin composite build-up in all groups. After storage, SBS test was measured at cross head speed of 0.5 mm/min. Data were analyzed using one/two-way ANOVA and Tukey HSD test (α = 0.05). Normal dentin groups showed the highest SBS among different groups. There was a statistically significant difference between different etching times in CAD groups (p < 0.05), but there were no significant differences between SBS of SB adhesive to CAD with or without CPP-ACP pretreated in both etching times. Most of the failure modes were adhesive except in groups 1 and 5 which cohesive failure in composite was also observed. The results of our study indicated that extended etching time up to 45 seconds could enhance the SBS of CAD and approach nearly to SBS of normal dentin. Moreover, MI paste pretreatment had not significant effect on SBS of etch-and-rinse adhesive in CAD. Simultaneous application of extended etching time and CPP-ACP containing paste may be a suggested method in increasing the SBS of adhesive to CAD.

Diode laser irradiation increases microtensile bond strength of dentin.

Laser irradiation after the immediate application of dentin bonding systems (DBSs) and prior to their polymerization has been proposed to increase bond strength. The objective of this study was to evaluate the effect of diode laser irradiation (λ = 970 nm) on simplified DBSs through microtensile bond strength tests. Forty healthy human molars were randomly distributed among four groups (n = 10) according to DBSs used [Adper™ SingleBond 2 (SB) and Adper™ EasyOne (EO)], and the respective groups were irradiated with a diode laser (SB-L and EO-L). After bonding procedures and composite resin build-ups, teeth were stored in deionized water for 7 days and then sectioned to obtain stick-shaped specimens (1.0 mm2). The microtensile test was performed at 0.5 mm/min, yielding bond strength values in MPa, which were evaluated by two-way ANOVA followed by Tukey's test (p < 0.05) for individual comparisons. For both adhesive systems, diode laser irradiation promoted significant increases in bond strength values (SB: 33.49 ± 6.77; SB-L: 43.69 ± 8.15; EO: 19.67 ± 5.86; EO-L: 29.87 ± 6.98). These results suggest that diode laser irradiation is a promising technique for achieving better performance of adhesive systems on dentin.

Ethanol application protocols and microtensile dentin bond strength of hydrophobic adhesive

PurposeAvailable knowledge on whether complicated and time-consuming ethanol application protocols are required for effective bonds between hydrophobic resin adhesive and dentin is inconclusive. Therefore, aim of this study is to evaluate effects of different ethanol application protocols on microtensile bond strength of hydrophobic adhesive to bovine dentin. Materials and methodsBovine incisors were randomly divided into four groups (n = 3). Standardized dentin cavities were acid-etched with 37% H3PO4 and rinsed with water. Single Bond 2 applied to dentin with water-wet bonding was used as a control group. The rest groups had their dentine surface dehydrated according to different ethanol application protocols: Group 1 (Full-Chemical-Dehydration-Protocol) = 50%, 70%, 80%, 95% and 3 × 100%, 30 s for each ethanol application; Group 2 (Simplified-Chemical-Dehydration-Protocol I) = 100% ethanol applied for 60 s at one step and Group 3 (Simplified-Chemical-Dehydration-Protocol II) = 100% ethanol applied for only 20 s at one step, respectively. After ethanol applications, a primer (50% HelioBond + 50% absolute ethanol) was used, followed by the neat HelioBond application. Resin composite build-ups were then done. ResultsGroup 1 showed higher bond strength (27.46 ± 8.10). Group 1 showed bond strength statistically similar to Group 2 (22.75 ± 8.02) and Group 3 (25.16 ± 7.23) and statistically different to control group (34.06 ± 5.8). ConclusionResults indicated that different ethanol application protocols may not affect bond strength of hydrophobic adhesive to dentin. However, slight statistical difference existed between control and full chemical dehydration protocol.

English

Fracture of anterior teeth is common in childhood due to many factors including sports. Reattachment is now a routine option for dental professionals whenever patients walk in with the fractured segment. It is now considered to be the priority instead of a composite resin build-up for better aesthetics. The success of this treatment modality depends on various factors. This case report discusses a situation where the fractured maxillary lateral incisor in a 9 year old patient is reattached. The root formation was not complete and the fracture was not involving the pulp. Hence it was important to protect the pulp as well as allow the root formation to complete naturally. No evidence of pulp exposure was found on clinical examination. Reattachment of the fractured segment was done with a seventh generation bonding agent and resin composite to restore aesthetics. Patient will be under long term follow up. The primary motto is to restore aesthetics and wait for root completion.

Adjunctive application of chlorhexidine and ethanol-wet bonding on durability of bonds to sound and caries-affected dentine

ObjectivesTo examine the effect of adjunctive application of chlorhexidine (CHX) and ethanol-wet bonding (EWB) on bond durability and nanoleakage of hydrophobic adhesive to sound (SD) and caries-affected dentine (CAD). MethodsDentine surfaces of molars were etched after caries removal and randomly allocated to four groups (n=12). In Groups 1 and 2, dentine surfaces were saturated with either 2ml of 100% ethanol or 2ml of ethanol with 2% CHX for 60s. In Groups 3 and 4, dentine surfaces were saturated with either 15μL of distilled water or 15μL of distilled water with 2% CHX for 60s. Two coats of primer, followed by neat resin were applied and light-cured for 40s. Resin composite build-ups were placed and bonded specimens were sectioned for bond strength testing after 24h and 12 months’ storage in artificial saliva. Bond strength data were analyzed using 3-way ANOVA and SNK tests. Interfacial nanoleakage was evaluated after 24h and 12 months using a field-emission scanning electron microscopy and data were analyzed using Kruskal–Wallis test. ResultsSignificant differences were observed for the three factors: “substrate” (p<0.001), “rewetting agents” (p<0.001) and “time” (p<0.001) on bond strength. Incorporation of 2% CHX to EWB preserved bond strength to SD and CAD and reduced interfacial nanoleakage after 12 months. Incorporation of 2% CHX to WWB also preserved bond strength to SD after ageing. ConclusionsIncorporation of chlorhexidine to ethanol-wet bonding has an interaction effect on preservation of bond durability to sound and caries-affected dentine. Clinical significanceIncorporation of chlorhexidine to ethanol-wet bonding with hydrophobic adhesive enhances the success rate of aesthetic bonded restorations.