title: Shear bond strength to enamel and flexural strength of different fiber-reinforced composites.
abstract: OBJECTIVE
  To assess the shear bond strength to unground human enamel (ESBS) and flexural strength (FS) of different reinforcing fibers used in combination with a flowable composite resin.
  
  
  METHODS
  For ESBS testing, 90 human molars were selected and randomly divided into 9 groups (n = 10) according to the reinforcing fiber to be tested: 1. RTD Quartz Splint additionally impregnated at chairside with Quartz Splint Resin (RTD); 2. RTD Quartz Splint without additional impregnation; 3. Ribbond-THM (Ribbond) impregnated with OptiBond FL Adhesive; 4: Ribbond Triaxial (Ribbond) impregnated with OptiBond FL Adhesive; 5. Connect (Kerr) impregnated with OptiBond FL Adhesive; 6. Construct (Kerr) impregnated with Opti- Bond FL Adhesive; 7. everStick PERIO (Stick Tech); 8. everStick C&B (Stick Tech); 9. nonreinforced composite Premise flowable (Kerr). Cylinders of flowable composite reinforced with the fibers were bonded to the intact buccal surface of the teeth. After 24 h of storage, shear loading was performed until failure occurred. FS was assessed performing three-point bending test according to ISO Standard 4049/2000. ESBS and FS data were analyzed using one-way ANOVA, followed by Tukey's HSD test for post-hoc comparisons (p < 0.05).
  
  
  RESULTS
  For each group, the ESBS and FS, respectively, in MPa were: 1. 17.07 ± 4.52 and 472.69 ± 30.49; 2. 14.98 ± 3.92 and 441.77 ± 61.43; 3. 18.59 ± 5.67 and 186.89 ± 43.89; 4. 16.74 ± 6.27 and 314.41 ± 148.52; 5. 14.38 ± 4.14 and 223.80 ± 77.35; 6. 16.00 ± 5.55 and 287.62 ± 85.91; 7. 16.42 ± 3.67 and 285.35 ± 39.68; 8. 23.24 ± 5.81 and 370.46 ± 29.26; 9. 12.58 ± 4.76 and 87.75 ± 22.87. For most fibers, no significant difference in ESBS was found compared to the control group, except for everStick C&B, which yielded higher ESBS. Nonreinforced composite exhibited the lowest FS, while all fibers positively affected the FS.
  
  
  CONCLUSIONS
  Fiber reinforcement of flowable composite does not affect its ESBS. The flexural strength of FRCs is significantly influenced by fiber composition and pattern.
authors.affiliation: Department of Dental Materials and Fixed Prosthodontics of Siena, University of Florence and Siena, Italy. jelenajuloski@gmail.com
authors.forename: Jelena
authors.initials: J
authors.lastname: Juloski
authors.forename: Milos
authors.initials: M
authors.lastname: Beloica
authors.forename: Cecilia
authors.initials: C
authors.lastname: Goracci
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Chieffi
authors.forename: Agostino
authors.initials: A
authors.lastname: Giovannetti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vichi
authors.forename: Zoran R
authors.initials: ZR
authors.lastname: Vulicevic
authors.forename: Marco
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003743:Dental Enamel; D003799:Dental Stress Analysis; D005898:Glass; D006801:Humans; D008422:Materials Testing; D008963:Molar; D018583:Pliability; D020959:Polyethylene; D011095:Polyethylenes; D011791:Quartz; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D018709:Statistics, Nonparametric
chemical_list: D003188:Composite Resins; D011095:Polyethylenes; C084063:RIBBOND; D019279:Resin Cements; C496140:everStick; C009753:fiberglass; D011791:Quartz; D020959:Polyethylene