Retrospective Assessment of Endodontically Treated Teeth Replaced by Dental Implants.

INTRODUCTION: This study investigated endodontically treated teeth that were replaced by dental implants at the University of North Carolina (UNC) at Chapel Hill School of Dentistry. The primary objective of this study was to determine the reasons leading to the extraction of endodontically treated teeth and their subsequent replacement with dental implants. The secondary objective was to evaluate the proportion of these teeth that, according to experienced endodontists, could have been preserved. METHODS: The UNC-Chapel Hill's dental electronic health records between 2004 and 2019 were probed for implant placement that replaced root canal-treated teeth. Preextraction radiographs and clinical charts were examined to ascertain the primary reason related to the extraction and to compile a profile for each case. In cases in which endodontic failure was the primary reason for extraction, radiographs and clinical findings were evaluated by 2experienced endodontists to assess potential treatment options. RESULTS: Between 2004 and 2019, 29.3% (1564 of 5229) of teeth replaced by dental implants at UNC School of Dentistry had undergone root canal treatment, with the mandibular first molar being the most commonly replaced tooth. The leading reasons for extraction were recurrent caries associated with defective restoration (26.6%), fracture of coronal structure (21.5%), vertical root fracture (20.9%), compromised periodontal condition (13.8%), and endodontic failure (2.4%). Two experienced endodontists evaluated extractions due to endodontic failure and concluded that 61.7% of them could have been candidates for endodontic retreatment. CONCLUSION: Substantial loss of tooth structure was the leading cause of extraction of root canal-treated teeth, followed by vertical root fracture and periodontal disease. Although endodontic failure constituted a minor portion of the reasons for extraction, a considerable number of teeth were extracted due to vertical root fractures following root canal treatment. A significant proportion of the extracted teeth due to endodontic failure could have been considered as potential candidates for endodontic retreatment.

The effect of a deep-learning tool on dentists' performances in detecting apical radiolucencies on periapical radiographs.

OBJECTIVES: To determine the efficacy of a deep-learning (DL) tool in assisting dentists in detecting apical radiolucencies on periapical radiographs. METHODS: Sixty-eight intraoral periapical radiographs with CBCT-proven presence or absence of apical radiolucencies were selected to serve as the testing subset. Eight readers examined the subset, denoted the positions of apical radiolucencies, and used a 5-point confidence scale to score each radiolucency. The same subset was assessed by readers under two conditions: with and without Denti.AI DL tool predictions. For the two sessions, the performance of the readers was compared. The comparison was performed with the alternate free response receiver operating characteristic (AFROC) methodology. RESULTS: Localization of lesion accuracy (AFROC-AUC), specificity and sensitivity (by lesion) detection demonstrated improvements in the DL aided session in comparison with the unaided reading session. Subgroup performance analysis revealed an increase in sensitivity for small radiolucencies and in radiolucencies located apical to endodontically treated teeth.. CONCLUSION: The study revealed that the DL technology (Denti.AI) enhances dental professionals' abilities to detect apical radiolucencies on intraoral radiographs. ADVANCES IN KNOWLEDGE: DL tools have the potential to improve diagnostic efficacy of dentists in identifying apical radiolucencies on periapical radiographs.

Effect of Photodynamic Therapy on Postoperative Pain in Posterior Teeth with Symptomatic Apical Periodontitis.

This study aimed to evaluate the impact of photodynamic therapy (PDT) after root canal preparation on pain relief in posterior teeth presenting with symptomatic apical periodontitis (SAP). A visual analog scale (VAS) was completed by the patients which registered their pain perception as none (0), mild (1-3), moderate (4-7), or severe (8-10). Only patients who registered moderate or severe pain were included. Seventy patients were allocated to two groups (n=35): a control group (CG) without the PDT application and an intervention group with PDT application (PG). The same chemo-mechanical preparation was achieved in both groups. In the PG, 150 µM methylene blue (MB)Please remove the underline was placed inside the canal for 2 minutes and a 660 nm wavelength laser was applied through a fiber for 3 minutes (100 mW, 600 J/cm², total 18J). The patients were asked to register their pain perception in the VAS document after 24-h, 72-h, and 1-week intervals. The number of tablets taken for pain relief was also recorded. The Mann-Whitney, Students T-test and Fisher´s exact tests were used for statistical analysis (P < .05). After 1 week, 32 patients in the CG and 33 in the PG returned their VAS cards. The PG resulted in lower pain levels after the 24-hour interval (median 0) than the CG (median 2); there was no difference between both groups at 72-h and 1-week intervals. The decrease in pain was higher in the PG at all time-intervals when compared to the CG. There was no difference in the mean number of tablets taken for pain relief (P > .05). Within the limitations of this study, it can be concluded that PDT was efficient in decreasing pain in teeth presenting with SAP. There was no difference observed after 72 hours and there was no impact on the intake of pain relief medication.

Outcome Assessment of Teeth with Necrotic Pulps and Apical Periodontitis Treated with Long-term Calcium Hydroxide.

INTRODUCTION: The aim of this retrospective, cohort case series was 2-fold: (1) to evaluate the outcomes of teeth with necrotic pulps and apical periodontitis using long-term calcium hydroxide (Ca[OH]2) (healing was assessed via the periapical index [PAI] system) and (2) to explore the possible association of fractures in relation to long term Ca(OH)2 exposure. METHODS: A total of 242 cases, diagnosed with pulpal necrosis and apical periodontitis, were treated with long-term Ca(OH)2 using a standardized protocol. Injectable and powdered Ca(OH)2 were placed sequentially in the root canal system. All cases were re-evaluated within a 3-month period until radiographic healing was observed. Clinical and radiographic evaluations were performed annually. Pre- and postoperative periapical radiographs were evaluated using the PAI system. RESULTS: Of the 242 cases, 219 participants completed their treatment with annual follow-up. The average Ca(OH)2 time was 5.4 months with a range of 1-12 months. Overall, by the latest follow-up visit, 90.0% (197/219) were classified as "healed." The overall mean preoperative and postoperative PAI scores were 4.07 (±0.80) and 1.76 (±0.70), respectively. Kappa statistics showed an almost perfect agreement for inter-rater (κ = 0.91) and intrarater (κ = 0.95) reproducibility for both examiners. CONCLUSIONS: Within the limitations of this study, the use of long-term Ca(OH)2 in the treatment of teeth with necrotic pulps and apical periodontitis resulted in a predictable high outcome. There was no association observed between long-term Ca(OH)2 use and the incidence of fractures during this study. Ca(OH)2 is a suitable material of choice as an interappointment dressing for teeth diagnosed with pulpal necrosis and apical periodontitis.

Periapical Microsurgery: Assessment of Different Types of Light-emitting Diode Transilluminators in Detection of Dentinal Defects.

INTRODUCTION: This study evaluated 4 different light-emitting diode (LED) transilluminators and the impact of operator experience in the detection of dentinal defects through an ex vivo TRUEJAW surgical model (Dental Engineering Laboratories, Santa Barbara, CA). METHODS: Forty-four extracted and endodontically treated mandibular premolar teeth were evaluated. Teeth were mounted in the models followed by surgical flaps and osteotomies to expose the apical third of the roots. After apical resection, the root-end surfaces were randomly inspected for the presence or absence of dentinal defects using a dental operating microscope (DOM) at ×19.4 magnification by experienced and novice LED evaluators. The assessment was made with the DOM light and 4 masked LED transilluminators of different diameters and luminous flux. The teeth were examined outside the models to establish the ground truth. The sensitivity, specificity, and kappa and McNemar test values of each light source by examiner were calculated. RESULTS: The use of LED transilluminators improved the diagnostic sensitivity of dentinal defects when compared with the DOM light alone for both examiners. For the LED-experienced evaluator, the medium-low transilluminator had statistically significant higher sensitivity than the DOM light and the small-low and small-high transilluminators (P < .05). For the novice LED evaluator, the medium-high transilluminator had the highest sensitivity. There was a statistically significant difference between the sensitivities of the medium-low transilluminator between the examiners (P < .05). CONCLUSIONS: Within the limitations of this ex vivo surgical study, dentinal defects were more often detected with the LED transilluminators with a larger diameter and increased lumens. The operator's LED transilluminator experience was found to have a positive effect on the detection of dentinal defects using transillumination.

The effects of photodynamic therapy on postoperative pain in teeth with necrotic pulps.

This study aimed to determine the effects of photodynamic therapy (PDT) on postoperative pain after treatments of teeth with necrotic pulps. This randomized clinical trial consisted of 60 patients who presented for treatment of asymptomatic teeth. The patients were randomly assigned into the Control Group (CG) or the PDT Group (PG). The canals were instrumented with a reciprocating instrument (50.05) under 2.5% NaOCL irrigation. After instrumentation was completed, the canals were flooded with 1.56 µM/mL of methylene blue (MB), the optical fiber was inserted to the working length and applied for 3 min (P =100 mW, t =3 min, E = 18 J). The device emitted PDT only for the PG. The operator and the patient were both masked to the treatment protocol. After PDT, the root canal treatment was completed and the canals were filled. A card was given to the patients to document their pain perception through the 0-10 visual analogue scale (VAS) at 24 h, 72 h, and 1-week intervals. The Mann-Whitney and Fisher´s exact tests were used for statistical analysis (P < .05). The average pain level for the CG was 1.33 at 24 -hs and 0.50 at 72 -hs; for the PG, the average pain level was 0.37 at 24 -h and 0 at 72 -h (P < .05). After 1-week there was no report of pain. PDT had a significant effect in decreasing postoperative pain at 24- and 72 -h intervals in treatment of single-rooted teeth with necrotic pulps performed in one visit.

Resilon: Assessment of Degraded Filling Material in Nonhealed Cases.

INTRODUCTION: The Resilon obturation system (Pentron Clinical Technologies, Wallingford, CT) was discontinued a few years after its introduction as an alternative to traditional gutta-percha and sealer. Ex vivo models support anecdotal reports of degraded Resilon filling material; however, there is no previous clinical report of this degradation. This may represent a significant health concern for the patient and contribute to a higher clinical failure rate of Resilon-obturated root canals. The aim of this study was to determine the proportion of Resilon degradation in nonhealed endodontic cases compared with gutta-percha and sealer. METHODS: Patients previously treated with Resilon or gutta-percha who had a nonhealed root canal that needed retreatment were enrolled. Upon access, the previous filling material was classified as either degraded or intact. If there was a lack of solid, dense material remaining within the canal confirmed by passively placing a size 15 K-file to the working length, the filling material was considered to be degraded. RESULTS: The proportion of degradation between the 2 materials was statistically significant, with Resilon having a higher likelihood of degradation than gutta-percha in the bivariate analysis (P = .0003). CONCLUSIONS: This clinical observational study indicates that Resilon has a higher rate of degradation when compared with gutta-percha in nonhealed cases.

Long-term Outcomes of Endodontic Treatment Performed with Resilon/Epiphany.

INTRODUCTION: Resilon (Resilon Research LLC, Madison, CT) with Epiphany Sealer (Pentron Clinical Technologies, Wallingford, CT) was introduced into the market in 2004 as a new method of root canal obturation. This material as well as the traditionally used gutta-percha with AH Plus sealer (Dentsply Maillefer, Tulsa, OK) were in use over a 9-year span in the University of North Carolina endodontic clinics. Although Resilon was initially thought to create a "monoblock" seal between the material and the canal, in vitro studies later suggested this concept not to be true. The long-term outcome of Resilon using a validated radiographic index and a systematic approach has not been reported. The purpose of this retrospective cohort study was to radiographically evaluate the outcome of Resilon/Epiphany-treated root canals compared with traditional gutta-percha/AH Plus. METHODS: One hundred twenty-five teeth were radiographically evaluated using the periapical index; 80 were treated with Resilon and 45 with gutta-percha. Age, sex, tooth position, and number of months to follow-up were documented, and a multivariate analysis with odds ratio was performed. RESULTS: Resilon-treated teeth were 5.3 times more likely to have a periapical index of 3 to 5 at follow-up compared with gutta-percha (P = .009). Teeth presenting with preoperative lesions, regardless of the material used, were also more likely to present with a lesion at follow-up (P = .04). CONCLUSIONS: Teeth obturated with Resilon were more likely to present with a lesion at follow-up compared with gutta-percha obturated teeth after controlling for the presence of a preoperative lesion and the length to follow-up.

Periapical Microsurgery: A 4-dimensional Analysis of Healing Patterns.

INTRODUCTION: Currently, the success of periapical microsurgery is determined by the restoration of the lamina dura and the elimination of symptoms. However, inadequate site preservation may prevent later implant placement. Although not possible before, the advent of cone-beam computed tomographic imaging and computer-aided registration allows for indirect and accurate 3-dimensional analysis of the surgical site over time. This study analyzed the volumetric healing pattern of the buccal plate after periapical microsurgery, with a specific focus on the buccolingual thickness of bone and the regression of the surface contour of the cortical plate. METHODS: Thirty-seven patients were scheduled for follow-up at least 1 year after periapical microsurgery (median = 25 months, total range = 12-31 months). Volumetric healing was analyzed by converting preoperative and postoperative cone-beam computed tomographic images into digital 3-dimensional models. The models were then registered to be able to analyze the changes in volume over time. Analysis was completed using Geomagic software (3D Systems, Rock Hill, SC), which allowed for registration of the volumes, calculation of volume change, and calculation of the margin of error. RESULTS: Twelve cases qualified for volumetric analysis. The median volumetric reduction of the cortical plate was -24.9 mm3 (interquartile range = -8.94 to -67 mm3), with an average linear error of 0.7 mm. This corresponded to an average loss in buccolingual dimension of 0.1-0.25 mm. Regression of the cortical plate was within the margin of error in all cases. CONCLUSIONS: After periapical microsurgery, and in the absence of grafting materials or membranes, healing occurs with little to no regression of the buccal cortical plate.

Periapical Microsurgery: Do Root Canal-retreated Teeth Have More Dentinal Defects?

INTRODUCTION: This microsurgical clinical study evaluated if teeth that have undergone endodontic retreatment are associated with more dentinal defects than primary root canal-treated teeth. METHODS: One hundred fifty-five patients who underwent periapical microsurgery treatment in a private practice setting were evaluated. The root ends were resected, and the roots were inspected for the presence of dentinal defects through the surgical operating microscope with the help of a 0.8-mm-diameter light-emitting diode probe light and methylene blue dye. The root canal treatment history (primary vs retreatment) of the teeth was documented and related to the presence or absence of dentinal defects. Bivariate analysis was performed using the chi-square test, and a multivariate analysis was performed using logistic regression to evaluate possible confounding effects of patient age, sex, and tooth location on the association between treatment and the presence of dentinal defects. RESULTS: Of the 155 treated teeth, 33 were excluded (3 fractured and 30 missing treatment history). Of the remaining 122 included teeth, 73 (59.8%) had undergone primary root canal treatment and 49 (40.2%) retreatment. Sixteen teeth (22.5%) of the primary root canal group versus 33 (64.7%) of the retreatment group had dentinal defects. The proportion of retreated teeth with dentinal defects compared with primary treatment was statistically significant (P < .001) with a higher proportion of retreated teeth having dentinal defects. In the multivariate analysis, only the type of treatment was statistically significant (P < .001). CONCLUSIONS: This clinical study showed that root canal-retreated teeth are associated with more dentinal defects than primary root canal-treated teeth.

Light-emitting diode assessment of dentinal defects: the role of presumed extraction forces.

OBJECTIVES: The evaluation of iatrogenic dentinal defects in extracted teeth may be influenced by extraction forces and prolonged dry times. The purpose of this study was to compare the presence of dentinal defects in freshly extracted, periodontally compromised teeth with those in a group of teeth with uncontrolled extraction forces and storage time. MATERIALS AND METHODS: The experimental group consisted of eighteen roots obtained from teeth extracted due to periodontal reasons with class II or III mobility. They were kept in saline and sectioned within 1 hour following extraction. The control group consisted of matched root types obtained from an anonymous tooth collection, consistent with previous dentinal defect studies. The slices were obtained at 3, 6, and 9 mm from the apex. The imaging process exposed all specimens to no more than 60 seconds of dry time. The × 12.8 magnification was used for the 9 mm slices and × 19.2 magnification for the 3 mm and 6 mm slices under light-emitting diode (LED) transillumination. The root canal spaces and periodontal tissues were masked to minimize extraneous factors that might influence the evaluators. Chi-square test was used for statistical analysis. RESULTS: Dentinal defects were detected in 17% of the experimental group teeth, compared to 61% of control teeth (p = 0.015). CONCLUSIONS: LED transillumination assessment of freshly extracted roots with class II or III mobility showed smaller number of dentinal defects than roots with uncontrolled storage time and extraction forces. The use of freshly extracted roots with mobility should be considered for future dental defect assessment studies.

Cone-beam Computed Tomography Uses in Clinical Endodontics: Observer Variability in Detecting Periapical Lesions.

INTRODUCTION: The accurate interpretation of a cone-beam computed tomographic (CBCT) volume is critical in identifying the presence of disease correctly and consistently. The aim of this clinical study was to determine the effect of experience level on the detection of periapical lesions in CBCT volumes. METHODS: CBCT volumes of 22 maxillary molars were interpreted by 3 endodontic faculty, 3 endodontic residents, and 3 dental students. These groups were compared with the consensus opinion of 2 experienced oral and maxillofacial radiologists. The observers determined the presence or absence of apical radiolucencies for each root using a 5-point Likert scale. RESULTS: Compared with the radiologists, the average weighted kappa value for endodontic faculty was 0.49, for endodontic residents it was 0.35 and for dental students it was 0.32. Intrarater reliability for each group showed endodontic faculty having the highest average weighted kappa value of 0.68 followed by endodontic residents (0.48) and dental students (0.28). CONCLUSIONS: Clinicians' experience level appears to be correlated with their ability to correctly diagnose periapical disease in CBCT volumes. In addition, experience leads to better inter-rater reliability. In neither of these 2 categories was agreement found to be excellent, suggesting that more can be done to improve the CBCT interpretation skills of clinicians at various levels of experience.

Periapical Microsurgery: The Effects of Locally Injected Dexamethasone on Pain, Swelling, Bruising, and Wound Healing.

INTRODUCTION: The purpose of this prospective, double-blind, randomized clinical trial was to evaluate the postoperative healing of endodontic periapical microsurgery after local administration of dexamethasone. METHODS: Sixty patients were divided into 2 groups. The dexamethasone group received a single local submucosal injection of 4 mg dexamethasone, and the placebo group received a submucosal injection of saline solution at the conclusion of standardized periapical microsurgery. Acetaminophen and hydrocodone/acetaminophen were prescribed for pain relief. A Likert-like 6-point scale was used for self-evaluation of pain, bruising, swelling, and wound healing at 24, 48, 72, 96 hours and at 1 week. The number of tablets taken was registered. Data were analyzed using the chi-square and Fisher exact tests at a significance level of P < .05. RESULTS: No improvements in pain, bruising, and wound healing were registered at any time interval. No difference was found in the number of tablets taken for pain relief. Subjects who received the dexamethasone injection reported less swelling 24 hours after periapical microsurgery (P < .05) but showed no significant benefit for the longer follow-up periods. CONCLUSIONS: This study shows that a 4-mg dose of dexamethasone administered through a local submucosal injection after periapical microsurgery has minimal impact on pain, bruising, and apparent wound healing at any time over a 7-day interval, and the impact on swelling seems limited.

Periapical Microsurgery: Can Ultrasonic Root-end Preparations Clinically Create or Propagate Dentinal Defects?

INTRODUCTION: This clinical study evaluates the effect of ultrasonic root-end preparations on dentinal defect creation and propagation. METHODS: Eighty-four teeth were treated with periapical microsurgery using a modern microsurgical protocol in a private practice setting. The root apices were resected and inspected for dentinal defects with a surgical operating microscope and a 0.8-mm diameter light-emitting diode microscope diagnostic probe light, both before and after ultrasonic root-end preparations. A 3-grade scale (none, partial, and full dentinal defect) was used to assess the status of the roots before and after ultrasonic root-end preparation. RESULTS: Of the 84 treated teeth, 3 had a vertical root fracture, leaving a total of 81 teeth for assessment. Fifty-one teeth were intact upon resection and remained intact after root-end preparation. Twenty-six teeth had partial dentinal defects, and 14 (54%) of these propagated into full dentinal defects after root-end preparation. CONCLUSIONS: This periapical microsurgery study showed that ultrasonic root-end preparations are safe to use on intact roots. Preexisting dentinal defects can be propagated by ultrasonic root-end preparations. Through the use of light-emitting diodes, dentinal defects can be detected, special root-end management can be implemented, and more predictable outcomes may be achieved.

Light-emitting Diode Assessment of Dentinal Defects after Root Canal Preparation with Profile, TRUShape, and WaveOne Gold Systems.

INTRODUCTION: The objective of this study was to use light-emitting diode (LED) transillumination to assess the presence of dentinal defects in roots instrumented with 3 different root canal preparation systems: ProFile (Dentsply Tulsa Dental Specialties, Tulsa, OK), TRUShape (Dentsply Tulsa Dental Specialties), and WaveOne Gold (Dentsply Tulsa Dental Specialties). METHODS: Eighty mesial roots of mandibular molars presenting 2 canals were randomly divided into 4 different groups (n = 20) as follows: the control group, no root canal preparation was performed; the ProFile group, root canals were prepared with nickel-titanium ProFile sizes 20.06 and 25.06; the TRUShape group, root canals were prepared with nickel-titanium rotary TRUShape instrument sizes 20.06 and 25.06; and the WaveOne Gold group, root canals were prepared with the reciprocating WaveOne Gold instrument #25.07. The specimens were sliced at 3, 6, and 9 mm from the apex with a low-speed saw under water cooling. Microscopic pictures of the specimens were taken with the aid of LED; the root canal space was masked, and 2 independent evaluators assessed the images for the assessment of dentinal defects. The number of dentinal defects was recorded, and the chi-square test was used for statistical analysis (P < .05). RESULTS: The number of specimens presenting dentinal defects was as follows: the control group = 10, the ProFile group = 10, the TRUShape group = 13, and the WaveOne Gold group = 10. CONCLUSIONS: Using the novel LED method, no difference in the visualization of dentinal defects was found among the ProFile, TRUShape, and WaveOne systems and the control group. Previous studies using the traditional sectioning method lack proper control and should be evaluated with caution.

Second Mesiobuccal Canal Treatment in a Predoctoral Dental Clinic: A Retrospective Clinical Study.

The aim of this retrospective clinical study was to evaluate the location and treatment of second canals in mesiobuccal roots (MB2) of first and second maxillary molars in a predoctoral endodontic clinic by the graduating classes of 2008 to 2015. These results were compared to similar clinical studies. Included in the study were 368 root canal treatments performed by 310 third- and fourth-year dental students at one U.S. dental school. All cases were done under faculty supervision, and the students were instructed to use dental loupe magnification. Students' evaluation sheets were used to deteremine the total MB2 canals treated in first and second maxillary molars. The results showed that, overall, 72.55% of the teeth had an MB2 canal treated. The frequency was higher in first molars (75.91%) than in second molars (56.92%) (p<0.05). Third-year students were able to detect 39 MB2 canals in 57 maxillary molars (68.42%), while fourth-year students detected 228 MB2 canals in 311 teeth (73.31%) (p>0.05). Under proper supervision by experienced endodontists, these dental students were capable of treating MB2 canals in maxillary molars. The frequency of MB2 canals located and treated by dental students with the assistance of experienced professionals was higher in first than in second molars. No significant difference was found between third- and fourth-year students. The incidence of MB2 canals located and treated in this study was found to be similar to that in other clinical studies.

Visualization Enhancement of Dentinal Defects by Using Light-Emitting Diode Transillumination.

INTRODUCTION: Several recent studies have evaluated the presence of dentinal defects after root canal preparation in extracted human teeth by using the root sectioning methodology. The objective of this research was to investigate whether light-emitting diode (LED) transillumination enhances the visualization of dentinal defects by using a root sectioning methodology. METHODS: Forty mesial roots of mandibular molars were sectioned at 3, 6, and 9 mm from the apex with a low-speed saw under water cooling. Microscopic pictures of the specimens were taken by using ×19.2 magnification for the 3-mm slice and ×12.8 magnification for the 6- and 9-mm slices. The LED transillumination was done by positioning an LED probe at 4 different locations (mesial, distal, buccal, and lingual). The root canal lumen was masked, and 2 independent evaluators assessed the presence of dentinal defects on the non-LED and LED images. The number of dentinal defects was recorded, and χ(2) test was used for statistical analysis (P < .05). RESULTS: The number of slices presenting dentinal defects at 3, 6, and 9 mm were 2 (5%), 1 (2.5%), and 1 (2.5%), respectively, for the non-LED assessment and 8 (20%), 10 (25%), and 9 (22.5%), respectively, for the LED assessment. Overall, 4 of the specimens (10%) presented dentinal defects without LED evaluation, and 19 of the specimens (47.5%) presented dentinal defects with LED evaluation. This difference was statistically significant (P < .05). CONCLUSIONS: LED transillumination enhanced the visualization of dentinal defects in uninstrumented roots. The results from previous studies that used the traditional non-LED sectioning methodology should be evaluated with caution.

Nominal Size and Taper Analysis of Novel Metallurgy NiTi Files.

OBJECTIVE: The aim of this investigation was to assess the nominal tip diameter, taper and true pilot tip length of three nickel-titanium (NiTi) rotary files before and after use. METHODS: Three brands of NiTi files of size 25.08 were evaluated: ProTaper Uni-versal (Dentsply Tulsa Specialties, Tulsa, USA), Channels PT (Insight Endo for Henry Schein, Melville, NY) and ProTaper Gold (Dentsply Tulsa Specialties), with ten files from each brand (total n=30). Scanning electron microscope (SEM) images of the files at 50x magnification were acquired before and after the files were used on endodontic training blocks, and the images were analysed by two independent investigators using ImageJ software. The nominal tip diameter (D0), taper and true pilot tip length (measured as the distance from the advertised diameter size of the file to the tip of the file) were recorded for each file and were analysed for statistical differences using repeated measures of analysis of variance (r-ANOVA) and Tukey's post-hoc test (P<0.05). RESULTS: The marginal means of the nominal size showed statistically significant differences between brands of the same size; statistically significant differences were also observed between the advertised sizes and the actual sizes (P<0.001). The mean taper values showed statistically significant differences from the advertised (p<0.001) sizes, except for the ProTaper Gold (P=0.023) group. The changes in the true pilot tip length before and after use were not statistically significant (P>0.05). The pilot tip lengths varied between brands. CONCLUSION: All nominal tip diameters and most taper sizes of the analysed brands show statistically significant differences from the nominal sizes advertised by the manufacturers. The differences in true pilot tip lengths between brands indicate a current lack of standardization.

Mineral trioxide aggregate (MTA): its history, composition, and clinical applications.

Mineral trioxide aggregate (MTA) has been a revolutionary material in endodontics. Since its introduction in the 1990s several studies have demonstrated its use in various clinical applications. MTA has been extensively studied and is currently used for perforation repairs, apexifications, regenerative procedures, apexogenesis, pulpotomies, and pulp capping. This article will review the history, composition, research findings, and clinical applications of this versatile endodontic material.

Periapical microsurgery: the effect of root dentinal defects on short- and long-term outcome.

INTRODUCTION: The purpose of this prospective clinical study was to evaluate the clinical outcome of endodontic microsurgery on roots exhibiting the presence or absence of dentinal defects at 1-year and 3-year follow-up period. METHODS: One hundred fifty-five teeth were treated with periapical microsurgery using a modern microsurgical protocol in a private practice setting. The root apices were resected and inspected for dentinal defects with a surgical operating microscope and a 0.8-mm head diameter light-emitting diode microscope diagnostic probe light. After inspection, root-end preparations were performed using ultrasonic tips, and root-end fillings were placed. Follow-up visits occurred at 1 year and 3 years postoperatively. The primary outcome measure used was the change in the radiographic apical bone density, and the secondary outcome measure used was the absence of clinical symptoms. RESULTS: Of the 155 treated teeth, a total of 134 teeth were assessed at the 1-year follow-up and 127 teeth at the 3-year evaluation. In the "intact" group, 94.8% healed at 1 year, and 97.3% healed at 3 years. In the "dentinal defect" group, 29.8% healed at 1 year, and 31.5% healed at 3 years. The baseline root condition of either "dentinal defect" or "intact" showed a statistical difference in the healing outcome at both 1 and 3 years. CONCLUSIONS: This prospective periapical microsurgery study showed a significant superior clinical outcome for intact roots when compared with roots with dentinal defects at both 1 year and at 3 years postoperatively.