Gerald N. Glickman

Cyclic Fatigue Analysis of a New Generation of Nickel Titanium Rotary Instruments

Recently, a new generation of nickel-titanium (NiTi) rotary instruments including the Twisted File (TF; Sybron Dental Specialties, Orange, CA) and ProFile GT Series X (GTX; Denstply, Tulsa Dental Specialties, Tulsa, OK) was introduced to the market. The purpose of this study was to determine if these new NiTi instruments were more resistant to cyclic fatigue compared with traditionally ground NiTi rotary instruments such as EndoSequence (ES; Brasseler, Savannah, GA) and ProFile (PF; Dentsply, Tulsa Dental Specialties). Size #25 TF, ES, and PF and size #20 GTX with .04 and .06 tapers were tested in a simulated canal with 60 degrees angle of curvature and a 3-mm radius. The number of rotations until fracture was recorded for each instrument. Among both .04 and .06 tapered files, #20 GTX files performed significantly better than all other files tested with tip sizes of #25 (p < 0.001); this may be because of the increased flexibility in the #20 files compared with #25 files. TF was significantly more resistant to cyclic fatigue than ES (p < 0.05) but not different from PF (p > 0.05) with the same tip size. The new manufacturing processes appeared to offer greater resistance to cyclic fatigue in a simulated canal model.

Evaluation of Photodynamic Therapy Using a Light- emitting Diode Lamp against Enterococcus faecalis in Extracted Human Teeth

INTRODUCTION Photodynamic therapy (PDT) with high-power lasers as the light source has been proven to be effective in disinfecting root canals. The aim of this study was to evaluate the antimicrobial effect of PDT using toluidine blue O (TBO) and a low-energy light-emitting diode (LED) lamp after the conventional disinfection protocol of 6% NaOCl. METHODS Single-rooted extracted teeth were cleaned, shaped, and sealed at the apex before incubation with Enterococcus faecalis for 2 weeks. Roots were randomly assigned to five experimental groups and three control groups. Dentin shavings were collected from the root canals of all groups with a #50/.06 rotary file, colony-forming units were determined, and the bacterial survival rate was calculated for each treatment. RESULTS The bacterial survival rate of the NaOCl/TBO/light group (0.1%) was significantly lower (P < .005) than the NaOCl (0.66%) and TBO/light groups (2.9%). CONCLUSIONS PDT using TBO and a LED lamp has the potential to be used as an adjunctive antimicrobial procedure in conventional endodontic therapy.

Comparative Assessment of ActiV GP/Glass Ionomer Sealer, Resilon/Epiphany, and Gutta-Percha/AH Plus Obturation: A Bacterial Leakage Study

The objective of this study was to compare the sealing ability of ActiV GP/glass ionomer (GI) sealer (Brasseler USA, Savannah, GA), Resilon/Epiphany (Pentron Clinical Technologies, Wallingford, CT), and gutta-percha (GP)/AH Plus (Dentsply Maillefer, Tulsa, OK). Seventy-three human single-rooted teeth were randomly divided into three test groups (20 canals each) and two control groups (5 positive and 8 negative). Using Enterococcus faecalis, a split-chamber bacterial leakage model was developed to evaluate the sealing ability of the three obturation systems. Samples were monitored every 24 hours for 65 days. Thirteen teeth leaked in both the Resilon/Epiphany and GP/AH Plus groups, whereas 17 teeth leaked in the ActiV GP/GI group at the end of the observation period. There were no statistically significant differences in the resistance to leakage between the three obturation systems (p > 0.05).

Comparison of Vibringe, EndoActivator, and Needle Irrigation on Sealer Penetration in Extracted Human Teeth

INTRODUCTION Vibringe is a new device that allows continuous sonic irrigation of the canal system during endodontic treatment. The aim of this study was to compare the effect of different irrigation systems on sealer penetration into dentinal tubules of extracted single-rooted teeth. METHODS Fifty single-rooted human teeth were instrumented and randomly divided into 4 groups: group 1 (control), saline; group 2 (conventional irrigation), 17% EDTA followed by 6% NaOCl; group 3 (EndoActivator), same irrigants as group 2; group 4 (Vibringe), same irrigants as group 2. Obturation of all teeth was done with gutta-percha and SimpliSeal labeled with fluorescent dye. Transverse sections at 1 mm and 5 mm from the root apex were examined by using confocal laser scanning microscopy. Percentage and maximum depth of sealer penetration were measured by using NIS-Elements Br 3.0 imaging software. RESULTS Groups 3 and 4 had a significantly greater percentage of the canal wall penetrated by sealer at the 5-mm level than group 1 (P < .0125), but not group 2. No other differences were found between the groups at either section level for both the percentage of sealer penetration and maximum depth. The 5-mm sections in each experimental group had a significantly higher percentage and maximum depth of sealer penetration than did the 1-mm sections (P < .0125). CONCLUSIONS The use of sonic activation with either the EndoActivator or Vibringe did not significantly improve the sealer penetration when compared with conventional irrigation.

AAE Consensus Conference on Diagnostic Terminology: background and perspectives.

Diagnostic terminology in endodontics has been a topic of discussion, controversy, and debate for decades. Confusion in terminology naturally arises when educators, clinicians, and researchers use a wide array of diagnostic diction and schematics; when there are distinct differences in definitions of terms; when key endodontic textbooks promulgate histologically based characterizations for clinically based diagnoses; and when there are strong proponents of specific classification systems. Reasons for these disparities are myriad and multifactorial because diagnosis is already, in its own right, a complex and challenging process. Furthermore, there is a lack of biologically based terms that can represent the true status of the pulp and periapical tissues, poor correlations exist between clinical symptomatology and pulpal histopathology, and lack of sophistication with current armamentaria endorses confusion. Moreover, questionable reliability and validity with current testing modalities are ignored, passionate and ‘‘ego-driven’’ beliefs about specific terms are rampant, and disagreement as to whether diagnostic terminology should be linked to specific treatment modalities has not been formally assessed. What further complicates this process even more is the contemporary evolution of indirect pulp capping as a viable therapeutic entity, as well as revascularization/regeneration procedures in which innovative treatments are being considered for pulpal and periapical conditions that were originally destined for pure endodontic treatment. Because a biologically and metrically based set of terminology is lacking, the Board of Directors of the American Association of Endodontists (AAE) recommended the construction and adoption of a consensus-driven, evidence-based classification system for endodontic diagnosis to arrive at conformity in terminology, enhance communication between clinicians and health care providers, and ultimately provide predictable treatment for patients on the basis of sound and reproducible diagnoses. The overall strategy of this approach was similar to that used by other medical and dental groups focused on developing standards in terminology. After nearly a year of planning, the AAE held its first ever Consensus Conference on the topic of ‘‘Standardization of Diagnostic Terms Used in Endodontics’’ on October 3, 2008 in Chicago, Illinois. Generously funded by the AAE Foundation, this conference was by invitation only. Sixty-four attendees addressed the wide variation in terms, with the intent of reaching consensus on the terminology, definitions, evaluation criteria, and treatment modalities for pulpal and periapical disease. The initial impetus for this event arose from the 2007 AAE Program Directors Workshop at which attendees unanimously expressed their concerns over the lack of standardized diagnostic terms, especially across the spectrum of predoctoral endodontics curricula at United States and Canadian dental schools, endodontic textbooks, the American Board of Endodontics, the AAE Glossary of Endodontic Terms, and materials used for construction of national dental board exams. As a result of that discussion, along with the impending impact of electronic claims codes on reimbursement, the AAE Board of Directors, under 2008– 2009 President Louis E. Rossman, ultimately approved a consensus conference to address these issues. In turn, a special committee composed of Drs Gerald N. Glickman as chair, Leif K. Bakland, Ashraf F. Fouad, Kenneth M. Hargreaves, and Scott A. Schwartz was appointed to conceptualize, design, and implement the conference. Both short-term and long-term goals were identified early in the discussions of standardizing diagnostic terminology. The 1-year, short-term goals related primarily to the development, implementation, and outcomes of the consensus conference itself. These included directives to do the following:

Contemporary perspectives on vital pulp therapy: views from the endodontists and pediatric dentists.

The purpose of this study was to determine the level of agreement between pediatric dentists and endodontists at a pulp therapy symposium conjointly sponsored by the American Association of Endodontists (AAE) and the American Academy of Pediatric Dentistry (AAPD) on November 2-3, 2007. Presymposium and postsymposium tests were administered, and respondent answers were compared between pediatric dentists and endodontists. Opinions on 3 areas were sought: pulp therapy for cariously involved primary teeth; indirect pulp treatment (IPT) for cariously involved immature permanent teeth; and innovative treatment options including pulpal revascularization and regeneration. Results were analyzed with chi2 tests. Comparisons of presymposium and postsymposium responses and between the 2 groups of attendees indicated that the pediatric dentistry and endodontic communities agree that formocresol will be replaced as a primary tooth pulpotomy agent, that mineral trioxide is the first choice to take its place, that IPT in primary teeth holds hope as a replacement for pulpotomy, and that IPT is an acceptable pulp therapy technique for cariously involved young permanent teeth. Both groups believe that pulp revascularization and regeneration will be viable treatment modalities in the future. The AAE and the AAPD are positioned to begin preparation of best practice guidelines that share common language and treatment recommendations for pulp therapies performed by both specialties.

The Efficacy of IntraFlow Intraosseous Injection as a Primary Anesthesia Technique

The purpose of this study was to compare the efficacy of intraosseous injection and inferior alveolar (IA) nerve block in anesthetizing mandibular posterior teeth with irreversible pulpitis. Thirty human subjects were randomly assigned to receive either intraosseous injection using the IntraFlow system (Pro-Dex Inc, Santa Ana, CA) or IA block as the primary anesthesia method. Pulpal anesthesia was evaluated via electric pulp testing at 4-minute intervals for 20 minutes. Two consecutive 80/80 readings were considered successful pulpal anesthesia. Anesthesia success or failure was recorded and groups compared. Intraosseous injection provided successful anesthesia in 13 of 15 subjects (87%). The IA block provided successful anesthesia in 9 of 15 subjects (60%). Although this difference was not statistically significant (p = 0.2148), the results of this preliminary study indicate that the IntraFlow system can be used as the primary anesthesia method in teeth with irreversible pulpitis to achieve predictable pulpal anesthesia.

A Retrospective Clinical and Radiographic Study on Healing of Periradicular Lesions in Patients Taking Oral Bisphosphonates

INTRODUCTION Bisphosphonates have been related to impaired bone remodeling. The impact of oral bisphosphonates on periradicular healing has not been studied. The purpose of this study was to evaluate the healing of periradicular lesions in patients taking oral bisphosphonates after root canal therapy. METHODS Thirty-four teeth with preoperative periradicular radiolucencies were identified in patients undergoing oral bisphosphonate therapy. These cases were examined clinically and radiographically to determine treatment outcome. Thirty-eight control teeth were selected from a pool of patients not taking bisphosphonates. Nonsurgical root canal treatment and retreatment was performed by endodontic residents and undergraduate dental students at Baylor College of Dentistry using nonstandardized protocols. RESULTS In the bisphosphonate group, 73.5% of the lesions healed, whereas the control cases had a healing rate of 81.6%. There was no statistically significant difference between the groups (p > 0.05). CONCLUSION The results of this preliminary short-term study suggest that patients taking long-term oral bisphosphonates can expect a satisfactory outcome with evidence of periradicular healing after conventional root canal treatment. Thus, root canal treatment may be considered a safe and realistic alternative to extraction in patients on bisphosphonate therapy.

Magnification's Effect on Endodontic Fine Motor Skills

INTRODUCTION The purpose of this study was to quantitatively investigate the effect of magnification on fine motor skills used in endodontics. METHODS This study used a novel manual dexterity test that was performed with and without magnification. An 8x operating microscope and 2.5x dental loupes were used for the magnification tests. Forty subjects, 20 with microscope experience and 20 without, participated in the study. Performance on the test was evaluated by using an accuracy scoring system, and the time needed to complete the test was recorded for each subject. RESULTS A significant increase in accuracy score with each level of magnification was demonstrated (P <or= .05). In addition, the use of operating microscope significantly increased the time needed to complete the test among subjects with less than 3 years of microscope experience. CONCLUSIONS The use of magnification to enhance fine motor skills was supported in all age groups and experience levels.

Evaluation of compressive strength of hydraulic silicate-based root-end filling materials.

INTRODUCTION Hydraulic silicate cements such as mineral trioxide aggregate (MTA) have many clinical advantages. Newer hydraulic silicate materials have been developed that improve on the limitations of mineral trioxide aggregate such as the long setting time and difficult handling characteristics. The purpose of this study was to examine the effect of saline and fetal bovine serum (FBS) on the setting and compressive strength of the following hydraulic silicate cements: ProRoot MTA (white WMTA; Dentsply International, Tulsa Dental Specialties, Johnson City, TN), EndoSequence Root Repair Material (Brasseler USA, Savannah, GA), MTA Plus (MTAP; Avalon Biomed Inc, Bradenton, FL), and QuickSet (QS; Avalon Biomed Inc, Bradenton, FL). METHODS Samples of root-end filling materials were compacted into polyethylene molds. Samples were exposed to FBS or saline for 7 days. A universal testing machine was used to determine the compressive strengths. RESULTS QS had significantly lower compressive strength than all other materials (P < .001). White MTA and MTAP mixed with liquid had lower compressive strengths after exposure to FBS compared with saline (P = .003). ERRM, MTAP mixed with gel, and QS were not affected by the exposure to FBS. CONCLUSIONS New silicate-based root-end filling materials, other than QS, have compressive strength similar to MTA. Within the limits of this study, premixed materials and those mixed with antiwashout gel maintain their compressive strength when exposed to biological fluids.