• Broad-spectrum, long-term antibiofilm features of metallic nanoparticles and antibacterial monomers on dental adhesive and resin composite surfaces

      Melo, Mary Anne; Weir, Michael D.; Cheng, Lei; Zhang, Ke; Xu, Hockin H. K. (2016-10)
      Concerns about the development of caries at the margins of restorations have been taken into consideration since the main reason for composite restoration failure in the long term is secondary caries. Restorative dental materials such as resin composite and adhesive systems are in contact with tooth and can be the ideal vehicle for delivering anticaries agents. Based on nanotechnology, silver nanoparticles (NAg) were developed and incorporated into dental resin-based materials. These nano-sized particles in the resin-based dental materials increased the ion release due to the higher surface area of the nanoparticles. Recent studies have demonstrated the capability of these materials for reduce bacterial load without detriment of their mechanical properties.
    • Implications of underperforming light energy delivery for posterior composite: insights into delivered radiant exposure, degradation characteristics, and biofilm formation.

      Maktabi, Haifa; Melo, Mary Anne (2018)
      Poor curing of composites due to incorrect position of a curing unit may trigger a negative pathway of events related to the bacterial growth-stimulating effect of released methacrylate monomers. An increased bacterial adhesion and biofilm formation as a result of incomplete polymerization may contribute to premature failure of posterior composite via secondary caries formation. The objectives of each chapter are: 1) to review the literature concerning the light curing process and implications for failures on posterior composites (chapter 1), 2) to investigate in vitro how the variations on light curing tip placement and irradiance exposure can impact the degree of conversion of conventional 2mm-increment composite and S. mutans biofilm formation (chapter 2). In summary, this set of studies support the importance of proper light curing for an acceptable clinical performance of posterior composites.
    • Prevalence of Atypical Radiographic Findings in Bitewings of Class II Composite Restorations: Detection and Assessment of Radiolucent Areas

      Bazerbashi, Jood; Melo, Mary Anne (2020)
      This retrospective study aimed to describe the prevalence of radiographic abnormalities in bitewing radiographs of proximal class II composite restorations. Bitewing radiographs of proximal composite restorations of adult patients who underwent restorative care at predoctoral clinics at the University of Maryland School of Dentistry from August 2014 to July 2016 were identified. Atypical radiographic features were categorized by type of material and location. The information recorded for patients included age, sex, tooth, and restored surface. Out of the 669 examined restorations, 16.5% radiographs showed no atypical radiographic findings and 83.5% restorations had unusual radiographic signs. The types of atypical radiographic findings were distributed as 16.5% internal voids, 3% overhang, 7.8% interlayer lines, 12.6% secondary caries, 20.7% interfacial gaps and 23.1% had multiple atypical findings. There is high prevalence of atypical radiographic findings in class II composite restorations, particularly in the body of the composite, premolars, and disto-occlusal restorations.