Publications

Scholarly Journals--Accepted

Scholarly Journals--Published

  • Enhancement of peripheral seal of medical face masks using a 3-dimensional-printed custom frame Abu Ahmed, Zhe Zhong, Montry Suprono, Roberto Savignano, Holli Riter, Udochukwu Oyoyo, Alisa Wilson, Rebecca Reece, Jessica Kim, Eun-Hwi Cho, Robert Handysides, Paul Richardson, Joseph Caruso, Yiming Li Background: During the COVID-19 pandemic, American Society for Testing and Materials level 3 and level 2 medical face masks (MFMs) have been used for most health care workers and even for the first responders owing to a shortage of N95 respirators. However, the MFMs lack effective peripheral seal, leading to concerns about their adequacy to block aerosol exposure for proper protection. The purpose of this study was to evaluate the peripheral seal of level 3 and level 2 MFMs with a 3-dimensional (3D-) printed custom frame. Methods: Level 3 and level 2 MFMs were tested on 10 participants with and without a 3D-printed custom frame; the efficiency of mask peripheral seal was determined by means of quantitative fit testing using a PortaCount Fit Tester based on ambient aerosol condensation nuclei counter protocol. Results: The 3D-printed custom frame significantly improved the peripheral seal of both level 3 and level 2 MFMs compared with the masks alone (P < .001). In addition, both level 3 and level 2 MFMs with the 3D-printed custom frame met the quantitative fit testing standard specified for N95 respirators. Practical implications: The 3D-printed custom frame over level 3 and level 2 MFMs can offer enhanced peripheral reduction of aerosols when using collapsible masks. With the shortage of N95 respirators, using the 3D-printed custom frame over a level 3 or level 2 MFM is considered a practical alternative to dental professionals. Keywords: ASTM; MFM; fit factor; level 2; level 3; peripheral seal (07/2021) (link)
  • Enhancement of peripheral seal of medical face masks using a 3-dimensional-printed custom frame Abu Ahmed, Zhe Zhong, Montry Suprono, Roberto Savignano, Holli Riter, Udochukwu Oyoyo, Alisa Wilson, Rebecca Reece, Jessica Kim, Eun-Hwi Cho, Robert Handysides, Paul Richardson, Joseph Caruso, Yiming Li Background: During the COVID-19 pandemic, American Society for Testing and Materials level 3 and level 2 medical face masks (MFMs) have been used for most health care workers and even for the first responders owing to a shortage of N95 respirators. However, the MFMs lack effective peripheral seal, leading to concerns about their adequacy to block aerosol exposure for proper protection. The purpose of this study was to evaluate the peripheral seal of level 3 and level 2 MFMs with a 3-dimensional (3D-) printed custom frame. Methods: Level 3 and level 2 MFMs were tested on 10 participants with and without a 3D-printed custom frame; the efficiency of mask peripheral seal was determined by means of quantitative fit testing using a PortaCount Fit Tester based on ambient aerosol condensation nuclei counter protocol. Results: The 3D-printed custom frame significantly improved the peripheral seal of both level 3 and level 2 MFMs compared with the masks alone (P < .001). In addition, both level 3 and level 2 MFMs with the 3D-printed custom frame met the quantitative fit testing standard specified for N95 respirators. Practical implications: The 3D-printed custom frame over level 3 and level 2 MFMs can offer enhanced peripheral reduction of aerosols when using collapsible masks. With the shortage of N95 respirators, using the 3D-printed custom frame over a level 3 or level 2 MFM is considered a practical alternative to dental professionals. Keywords: ASTM; MFM; fit factor; level 2; level 3; peripheral seal (07/2021) (link)
  • A clinical investigation of dental evacuation systems in reducing aerosols Montry S Suprono, John Won, Roberto Savignano, Zhe Zhong, Abu Ahmed, Gina Roque-Torres, Wu Zhang, Udochukwu Oyoyo, Paul Richardson, Joseph Caruso, Robert Handysides, Yiming Li Background: The route of transmission of severe acute respiratory syndrome coronavirus 2 has challenged dentistry to improve the safety for patients and the dental team during various treatment procedures. The purpose of this study was to evaluate and compare the effectiveness of dental evacuation systems in reducing aerosols during oral prophylactic procedures in a large clinical setting. Methods: This was a single-center, controlled clinical trial using a split-mouth design. A total of 93 student participants were recruited according to the inclusion and exclusion criteria. Aerosol samples were collected on blood agar plates that were placed around the clinic at 4 treatment periods: baseline, high-volume evacuation (HVE), combination (HVE and intraoral suction device), and posttreatment. Student operators were randomized to perform oral prophylaxis using ultrasonic scalers on 1 side of the mouth, using only HVE suction for the HVE treatment period and then with the addition of an intraoral suction device for the combination treatment period. Agar plates were collected after each period and incubated at 37 °C for 48 hours. Colony-forming unit (CFU) counts were determined using an automatic colony counter. Results: The use of a combination of devices resulted in significant reductions in CFUs compared with the use of the intraoral suction device alone (P < .001). The highest amounts of CFUs were found in the operating zone and on patients during both HVE and combination treatment periods. Conclusions: Within limitations of this study, the authors found significant reductions in the amount of microbial aerosols when both HVE and an intraoral suction device were used. Practical implications: The combination of HVE and intraoral suction devices significantly decreases microbial aerosols during oral prophylaxis procedures. (06/2021) (link)
  • A Retrospective Comparison of Outcome in Patients Who Received Both Nonsurgical Root Canal Treatment and Single-tooth Implants Seyed Aliakbar Vahdati , Mahmoud Torabinejad , Robert Handysides , Jamie Lozada  Currently, no study has compared the outcome of nonsurgical root canal treatment (NSRCT) and single-tooth implants (STIs) provided to the same patient. The purpose of this study was to determine if the survival outcome of the 2 treatment modalities is different. Methods: The medical/dental records of 3671 patients with at least 1 STI and 1 NSRCT were reviewed. One hundred seventy patients with at least a 5-year follow-up were included. The survival outcome of NSRCT and STI and related factors were evaluated. Results: Both treatments had a 95% survival rate with a mean 7.5-year follow-up. Most preoperative and postoperative factors involved in both procedures had no significant effect on the treatment outcomes. The number of adjunct and additional treatments, the number of appointments, the elapsed time before the final restoration, the number of prescribed medications, and the cost of the treatment were significantly higher for STI in comparison with NSRCT. Conclusions: Both NSRCT and STI are highly successful treatments. Compromised teeth that could otherwise be saved by NSRCTs and deemed restorable should not routinely be treatment planned for STI (02/2020) (link)
  • Evidence-Based Practice Knowledge, Perceptions, and Behavior: A Multi-Institutional, Cross-Sectional Study of a Population of U.S. Dental Students Cheryl L Straub-Morarend, Christine R Wankiiri-Hale, Derek R Blanchette, Sharon K Lanning, Tanja Bekhuis, Becky M Smith, Abby J Brodie, Deise Cruz Oliveira, Robert A Handysides, Deborah V Dawson, Heiko Spallek  The aim of this study was to help inform faculty and curriculum leaders in academic dental institutions about the knowledge, skills, perceptions, and behavior of an institutionally diverse population of dental students with respect to evidence-based practice (EBP). A survey utilizing the validated Knowledge, Attitudes, Access, and Confidence Evaluation instrument developed by Hendricson et al. was conducted in 2012 with fourth-year dental students at seven geographically dispersed U.S. dental schools. The survey addressed elements of EBP knowledge, attitudes toward EBP, behavior in accessing evidence, and perceptions of competence in statistical analysis. A total of 138 students from the seven schools participated. A slight majority of these students correctly responded to the knowledge of critical appraisal questions. While the students demonstrated positive attitudes about EBP, they did not report high levels of confidence in their critical appraisal skills. The findings also showed that the students accessed various sources of evidence with differing frequencies. The most frequently accessed resources were colleagues, the Internet (excluding Cochrane Database of Systematic Reviews), and textbooks. The results of this study help to identify areas for improvement in EBP education in order to advance dental students' preparation to become evidence-based practitioners. KEYWORDS: dental education; evidence-based dentistry; evidence-based practice PMID: 27037451 (04/2016) (link)
  • Effect of apex size on the leakage of gutta-percha and sealer-filled root canals Tory Silvestrin, Mahmoud Torabinejad, Robert Handysides, Shahrokh Shabahang Objectives: There are no data comparing coronal leakage of teeth prepared to different apical sizes and obturated with gutta-percha and sealer. The aim of this study was to investigate the effect of apical preparation size on the leakage of obturated root canals. Large apical openings are encountered as a result of pulp necrosis in immature teeth, apical resorption, or over-enlargement of the apical foramen. Complete cleaning, shaping, obturation, and apical seal of root canal systems are essential for the success of root canal treatment. Method and materials: One hundred twenty-five extracted human teeth were divided into groups containing 25 samples each and prepared to apical file sizes 30, 40, 50, 60, and 70. Twenty teeth served as positive and negative controls. Obturation was completed with gutta-percha and sealer via warm vertical compaction. Bacterial leakage was investigated after 112 days using Proteus vulgaris. Data were analyzed via independent-samples Kruskal-Wallis test. Results: The average time for leakage of apical preparation sizes 30, 40, 50, 60, and 70 were 57.5, 52.4, 47.2, 37.5, and 28.4 days, respectively. Significant differences in leakage were observed between apical preparation sizes 70 versus 30, 70 versus 40, 70 versus 50, as well as 60 versus 30. A trend for more leakage occurred when apical preparation sizes exceeded size 60. Conclusions: Based on these results, it appears leakage of gutta-percha and sealer as obturation materials increases when apical preparation size exceeds 60. Consideration should be given to using sealing materials other than gutta-percha and sealer when the apex size exceeds 60. (01/2016) (link)
  • Survival of Intentionally Replanted Teeth and Implant-supported Single Crowns: A Systematic Review. Mahmoud Torabinejad, Nathan A Dinsbach, Michael Turman, Robert Handysides, Khaled Bahjri, Shane N White    Introduction: Although nonsurgical initial root canal treatment and retreatment have high success rates, penapical disease can remain. The survival rates of 2 surgical procedures, intentionally replanted (IR) teeth and implant-supported single crowns (ISCs), have yet to be compared. The purpose of this systematic review and meta-analysis was to examine the literature and quantify the survival of IR teeth and compare it with that of ISCs. Methods: Systematic searches were enriched by citation mining. Weighted survival means and 95% confidence intervals (CI) were estimated using a random-effects model and compared. Results: The quality of the IR and ISC articles was only moderate. Data for ISCs were much more plentiful than for IR teeth. Meta-analysis revealed a weighted mean survival of 88% (95% CI, 81%-94%) for IR teeth. Root resorption was reported with a mean prevalence of 11%. The weighted mean survival of ISCs was 97% (95% CI, 96%-98%). The mean survival of ISCs was significantly higher than that of IR teeth (P < .001). A recent study on IR teeth indicated that orthodontic extrusion before intentional replantation improved survival rates. Conclusions: A systematic review and meta-analysis found that the mean survival of ISCs was significantly higher than IR teeth. However, treatment decisions must be based on a wide variety of treatment and patient-specific parameters. Intentional replantation may have a role when ISC is not practicable. Studies using contemporary treatment and analytic methods should be used to identify and measure intentional replant prognostic and treatment variables. (07/2015) (link)
  • Ordinola-Zapata R, Bramante C M, Aprecio R M, Handysides R, & Jaramillo D E. (2014). Biofilm removal by 6% sodium hypochlorite activated by different irrigation techniques. Int Endod J, 47(7), 659-666. Aim To compare the removal of biofilm utilizing four irrigation techniques on a bovine root canal model. Methodology Fifty dentine specimens (2 x 2 mm) were infected with biofilm. The samples were then adapted to previously created cavities in the bovine model. The root canals were irrigated twice with 2 mL of 6% sodium hypochlorite for 2 min (4 min total). Following initial irrigation, the different treatment modalities were introduced for 60 s (3 x 20 s intervals). The evaluated techniques were needle irrigation, Endoactivator (Dentsply Tulsa Dental, Tulsa, OK, USA), passive ultrasonic irrigation and laser-activated irrigation (photon-induced photoacoustic streaming). The controls were irrigated with distilled water and conventional needle irrigation. Subsequently, the dentine samples were separated from the model and analysed using a scanning electron microscope (SEM). Fifteen operative fields were scanned per block, and SEM pictures were captured. Two calibrated evaluators examined the images and collected data using a four-degree scale. Nonparametric tests were used to evaluate for statistical significance amongst the groups. Results The group undergoing laser-activated irrigation using photon-induced photoacoustic streaming exhibited the most favourable results in the removal of biofilm. Passive ultrasonic irrigation scores were significantly lower than both the Endoactivator and needle irrigation scores. Sonic and needle irrigation were not significantly different. The least favourable results were found in the control group. Conclusions Laser activation of 6% sodium hypochlorite significantly improved the cleaning of biofilm-infected dentine followed by passive ultrasonic irrigation. (07/2014) (link)
  • Brodie A J, Crow H C, Eber R M, Handysides R, Holexa R, Kiat-amnuay S, & Spallek H. (2011). Evaluating Postdoctoral Dental Candidates: Assessing the Need and Recommendations for a National Qualifying Examination. Journal of Dental Education, 75(6), 719-725. Increasingly, U.S. dental schools report pass/fail grades and do not rank students. In addition, the Joint Commission on National Dental Examinations will report National Board Dental Examination (NBDE) scores as pass/fail after January 1, 2012. This article discusses how these changes will force postdoctoral dental program directors to modify how they assess candidates and how noncognitive evaluations might enhance those assessments. The authors propose developing a national qualifying examination for postdoctoral dental programs that will measure knowledge, decision making, and noncognitive traits including empathy, self-confidence, integrity, and emotional intelligence. Without NBDE scores, class rank, and GPA as a basis for decision making, a single national qualifying examination would assist postdoctoral programs in selecting high-quality candidates based on knowledge, critical thinking skills, and noncognitive traits. (06/2011) (link)
  • Torabinejad M, Corr R, Handysides R, & Shabahang S. (2009). Outcomes of Nonsurgical Retreatment and Endodontic Surgery: A Systematic Review. Journal of Endodontics, 35(7), 930-937. Introduction: The purpose of this systematic review was to compare the clinical and radiographic outcomes of nonsurgical retreatment with those of endodontic surgery to determine which modality offers more favorable outcomes. Methods: The study began with targeted electronic searches of MEDLINE, PubMed, and Cochrane databases, followed with exhaustive hand searching and citation mining for all articles reporting clinical and/or radiographic outcomes for at least a mean follow-up of 2 years for these procedures. Pooled and weighted success rates were determined from a meta-analysis of the data abstracted from the articles. Results: A significantly higher success rate was found for endodontic surgery at 2-4 years (77.8%) compared with nonsurgical retreatment for the same follow-up period (70.9%; P <.05). At 4-6 years, however, this relationship was reversed, with nonsurgical retreatment showing a higher success rate of 83.0% compared with 71.8% for endodontic surgery (P <.05). Insufficient numbers of articles were available to make comparisons after 6 years of follow-up period. Endodontic surgery studies showed a statistically significant decrease in success with each increasing follow-up interval (P <.05). The weighted success for 2-4 years was 77.8%, which declined at 4-6 years to 71.8% and further declined at 6+ years to 62.9% (P <.05). Conversely, the nonsurgical retreatment success rates demonstrated a statistically significant increase in weighted success from 2-4 years (70.9%) to 4-6 years (83.0%; P <.05). Conclusions: On the basis of these results it appears that endodontic surgery offers more favorable initial success, but nonsurgical retreatment offers a more favorable long-term outcome. (J Endod 2009;35:930-937) (07/2009) (link)
  • Clinical implications of the smear layer in endodontics: a review Mahmoud Torabinejad, Robert Handysides, Abbas Ali Khademi, Leif K Bakland   (12/2002) (link)

Books and Chapters

  • Terauchi Y, Parirokh M, Handysides R. Nonsurgical Retreatment.  Endodontics Principles and Practice, 6th ed., Elsevier, Inc. 2021.  Chapter 19, pp 405-427 (2021)
  • Bogen G, Handysides RA. Retreatment.  Endodontics Principles and Practice, 5th ed., Saunders, an imprint of Elsevier, Inc. 2015.  Chapter 20, pp 355-375. (03/2015 - 2015)
  • Handysides RA, Bakland LK. Contemporary Restoration of Endodontically Treated Teeth: Evidence Based Diagnosis and Treatment Planning. Quintessence, 2012 Chapter 3 Treatment Planning and Considerations for Endodontically treated teeth   (11/2012)
  • Handysides R, Jaramillo D, Ingle J. Chapter 14, Endodontic Examination. Ingle and Bakland, 6th Ed., 2008 (07/2007)

Non-Scholarly Journals

  • Advance in clinical endodontic instruments:  The ever evolving endodontic instruments.  LLU Dentistry Journal, pg 24-27. (06/2010)
  • R. Handysides"Root Canals: Facts and Fiction." San Bernardino Sun 01 01 2007: (01/2007)