Effects of quaternary ammonium-methacrylates on the mechanical properties of unfilled resins

Tomohiro Hoshika, Yoshihiro Nishitani, Masahiro Yoshiyama, William O. Key, William Brantley, Kelli A. Agee, Lorenzo Breschi, Milena Cadenaro, Franklin R. Tay, Frederick Rueggeberg, David H. Pashley

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Objective. Adding antimicrobial/anti-MMP quaternary ammonium methacrylates (QAMs) tocomonomer blends should not weaken the mechanical properties of dental resins. This workevaluated the degree conversion and mechanical properties of BisGMA/TEGDMA/HEMA(60:30:10) containing 0-15 mass% QAMs A-E (A: 2-acryloxyethyltrimethyl ammo-nium chloride; B: [3-(methacryloylamino)propyl]trimethylammonium chloride; C: [2-(methacryloxy)ethyl] trimethyl ammonium chloride; D: diallyldimethyl ammoniumchloride; E: 2-(methacryloyloxy) ethyltrimethyl ammonium methyl sulfate.

Methods. Unfilled resins with and without QAM were placed on ATR-FTIR and light-polymerized for 20 s in a thin film at 30°C. Unfilled resin beams were casted from squarehollow glass tubings. Half of the beams were tested after 3 days of drying (control); the otherhalf were tested wet after 3 days of water storage.

Results. Addition of QAMs in control resins significantly increased conversion 600 s afterlight termination, with the exception of 5% MAPTAC (p < 0.05). Increase of QAM contentwithin a formulation significantly increased conversion. Control beams gave dry Young'smoduli of ∼700 MPa. Addition of 5, 10 or 15 mass% QAMs produced significant reductionsin dry Young's moduli except for 5% B or C. 15 mass% A, B and C lowered the wet Young'smoduli of the resin beams by more than 30%. The ultimate tensile stress (UTS) of controldry resin was 89 ± 11 MPa. Addition of 5-10 mass% QAMs had no adverse effect on the dryUTS. After water storage, the UTS of all resin blends fell significantly (p < 0.05), especiallywhen 15 wt% QAMs was added. Control dry beams gave fracture toughness (KIC) values of0.88 ± 0.1 MPa m1/2. Wet values were significantly higher at 1.02 ± 0.06 (p < 0.05). KIC of dry beams varied from 0.85 ± 0.08 at 5% QAMs to 0.49 ± 0.05 at 15% QAMs. Wet beams gave KIC values of 1.02 ± 0.06 MPa m1/2 that fell to 0.23 ± 0.01 at 15% QAMs.

Significance. Addition of 10% QAMs increased the degree of conversion of unfilled resins, but lowered wet toughness and UTS; addition of 15% QAMs lowered the mechanical properties of wet resins below acceptable levels.

Original languageEnglish (US)
Pages (from-to)1213-1223
Number of pages11
JournalDental Materials
Issue number11
StatePublished - Nov 1 2014


  • Dry-testing
  • Fracture toughness
  • Percent-conversion
  • Quaternary ammonium
  • TPO
  • Ultimate tensile strength
  • Wet-testing
  • Young's modulus
  • methacrylates

ASJC Scopus subject areas

  • Materials Science(all)
  • Dentistry(all)
  • Mechanics of Materials


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