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Background: There have been no reports on the impact of different reciprocating angles on retreatment performance of reciprocating files. This ex-vivo study compared the efficiency of three reciprocating systems in removing MTA-type sealer-based filling materials and investigated the influence of different reciprocating angles on their retreatment ability. Methods: 140 root-canals were instrumented to a 35 apical size and filled with an MTA-type sealer and gutta-percha cones. Samples were scanned by micro-computed-tomography and the root-canals fillings volumes were measured. Samples were divided into 7 groups according to the reciprocating angles at which the WaveOne-Gold (WOG), Reciproc-Blue (RB) and R-Motion (RM) systems were reciprocated to remove the root-canals' fillings. The WOG-150/30, WOG-90/30, RB-150/30, RB-90/30, RM-150/30 and RM-90/30 groups in which the systems were reciprocated at 150/30 and 90/30 (counterclockwise/clockwise) angles. In the RB-270/30 group the RB system was reciprocated at 270/30 angles. Samples were re-scanned and the remaining filling materials' (RFMs) volumes were measured. The percentage of the RFMs volume and its mean value for each group were calculated and data were statistically analysed at 0.05 significance level. Results: The WOG system resulted in less RFMs (2.24%) when reciprocated at 90/30 angles compared to that resulted from the 150/30 angles (4.96%) [P = 0.002]. The RB system reciprocated at 90/30 angles resulted in less RFMs (2.67%) compared to that resulted from the 270/30 angles (6.64%) [P = 0.001]. The RFMs after using RM system reciprocated at 90/30 (6.02%) and 150/30 (7.61%) were greater than those of WOG (2.24 and 4.96%) and RB (2.67 and 4.34%) reciprocated at the same angles (P < 0.05). The longest time required to remove the filling materials was recorded with the RB-270/30 group (6.06 min) [P = 0.00]. The times required when the WOG, RB and RM files reciprocated at 90/30 angles (3.59, 3 and 3.05 mins, respectively) were shorter than those when files were reciprocated at 150/30 angles (5.25, 4.98 and 3.67 min, respectively) [P < 0.05]. Conclusions: The WOG and RB systems removed more MTA-type sealer-based root-canals fillings than the RM system. Lower counterclockwise reciprocating angles improve the retreatment ability of reciprocating systems, especially the WOG system and can reduce the time required for retreatment procedures. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: A potentially damaging temperature rise within the root canal and thus on the external root surface may be induced because of frictional contact of ultrasonic tips during the removal of separated instruments. The efficiency of a new ultrasonic unit, with air-spray function and ET40D (Satelec/Acteon, Merignac, France) and CPR5 (Obtura-Spartan, Fenton, MO) ultrasonic tips, in reducing temperature rise on the external root surface during the removal of fractured files was investigated. Methods: Four millimeters of F2 ProTaper files (Dentsply, Surrey, UK) were fractured 2.5 mm from the canal access of 60 lower incisor roots. Roots were randomly divided into six groups: groups CPR5/no air and ET40D/no air in which tips were used without air flow, groups CPR5/15 psi and ET40D/15 psi (tips used with 15-psi air pressure), and groups CPR5/10 psi and ET40D/10 psi (10-psi air pressure). The temperature rise was measured on the external proximal root surface, adjacent to the most coronal aspect of the fractured fragment, at 15 seconds and then at 30-second intervals up to 120 seconds. Results: After 120 seconds, the mean temperature rise (4.2°C) with the air flow active was significantly lower than that with nonactive air flow (11°C). At 10- and 15-psi pressures, the temperature rise after 120 seconds induced by ET40D tips was 4° and 2.4°C, respectively. These were significantly lower than with CPR5 tips (6.3° and 4.2°C, respectively). Conclusions: A new ultrasonic unit incorporating an air-flow function proved to be effective in reducing the temperature rise during removal of fractured files. ET40D ultrasonic tips were more effective than the CPR5 tip. However, both tips could be safely activated with air spray up to 120 seconds. [Copyright &y& Elsevier]

Abstract: This in vitro study aimed to investigate the effect of ultrasonic removal of endodontic fractured files on tooth structure. Fifty-three canine roots were cleaned and weighed. They were scanned by a microcomputed tomography scanner producing two-dimensional images that were reconstructed into two-dimensional slices, and, finally, the canal volume was measured. In a control group, canals were prepared to F5-size ProTaper (Dentsply Ltd, Surrey, UK). In three experimental groups, F5-fractured files were ultrasonically removed from three root canal locations: coronal, middle, and apical. All roots were reweighed and rescanned. Reconstruction and analysis were performed to remeasure the canal volume. The differences in root mass (weight) and canal volume between before and after treatment were calculated. The highest change increase in canal volume was found when fractured files were removed from the apical part followed by middle and coronal. A positive correlation existed between canal volume and root mass changes. Microcomputed tomography scanning can reliably determine changes in canal volume resulting from fractured-file removal. [Copyright &y& Elsevier]

Background: To investigate the complications associated with the use of nickel titanium rotary instruments (NiTi-RIs) for root canal treatments (RCTs), in Saudi Arabia dental practice, and to explore the influencing factors. Methods: After obtaining an ethical approval, two pilot studies were conducted to formulate the final questionnaire. The sample size was measured taking into consideration 60% expected response rates and confidence level of 99.9%. The questionnaire was emailed to 600 general dentists (GDs) randomly selected from the dental register and all of the endodontists (175). The email's introduction clarified objectives of the study and guaranteed that all of the collected information would remain confidential. A reminder was sent after 10 weeks. The data were collected and analyzed using the chi-squared test at a 0.05 significance level. Results: With a 51% overall response rate, 71.9% off the respondents used NiTi-RIs. The majority (83.1%) experienced complications while using NiTi-RIs; with the instruments' fracture being significantly the most common complication (52.7%) (p < 0.001). The majority (87.7%) experienced NiTi-RIs' fractureat least once; with more endodontists (94.3%) than GDs (83.3%) (p < 0.001). The greater the number of weekly performed RCTs and participants' experiences, the more NiTi-RIs fractures and the greater the number of fracture incidents (p < 0.001). While 60% of those who performed 1–3 RCTs per week experienced NiTi-RIs fractures, 100% of those who performed more than 12 RCTs per week did so. The highest percentage of those who experienced more than 10 fractured NiTi-RIs (60%) was within the group who performed more than 12 RCTs per week. Although fracture incidents decreased with a smaller number of reuses, there was no significant correlation between the number of fractured instruments and NiTi-RIs discard strategy (p ≥ 0.05). Conclusion: Fracture incidence was the most common complication while using NiTi-RIs, regardless of the clinicians' experiences and skills. While the single use may reduce NiTi-RIs fractures, to some extent, the greater number of RCTs performed per week was the most influential factor. [ABSTRACT FROM AUTHOR]

Background: To establish the extent of using nickel titanium rotary instruments (NiTi-RIs), to identify reasons for using / not using NiTi-RIs, to explore usage modalities and to identify factors and measures that can increase implementation of NiTi-RIs in general dental practice. Methods: Two pilot questionnaires were conducted on academic staff members at College of Dentistry, Taibah University, general dentists (GDs) and endodontists to finalise the questionnaire. A sample size was calculated considering the expected and minimum accepted response rates (60 and 48%, respectively) and a 99.9% Confidence Level. The online-questionnaire was sent to 600 GDs and all endodontists (175) working in Saudi Arabia. A reminder was emailed after 10 weeks to encourage non-respondents to complete the questionnaire. Responses, were collected and converted into numerical data which were analysed using the Chi-square test (p = 0.05). Results: Significantly most respondents (71.9%) used NiTi-RIs (p < 0.001); with more endodontists (96.9%) than GDs (60%). Most users (62.5%) had been using NiTi-RIs for More than 3 years (p < 0001). The trend of using NiTi-RIs increased as participants' experience and the number of root-canal treatments performed per week increased (p = 0.021). While most respondents (45.3%) used NiTi-RIs because of faster root-canal preparation, the majority of non-users (85.3%) didn't do so because of high cost. The highest proportion (43.3%) reported better undergraduate education as the most important factor that can significantly increase NiTi-RIs usage. The majority (91.8%) prepared glide-path before using NiTi-RIs; especially with stainless steel hand-files (63.3%). Conclusions: NiTi-RIs are relatively well adopted in Saudi dental practice. However, better education, especially during undergraduate training and lower cost can increase their usage. Overall, clinicians showed good awareness of NiTi-RIs usage aspects which reflected on usage modalities. [ABSTRACT FROM AUTHOR]

Background: This study aimed at investigating dental clinicians' preferences on management of necrotic pulp with acute apical abscess (NPAAA) cases. Methods: Following an ethical approval and two pilot studies, an electronic survey was emailed to 400 general dental practitioners (GDPs) and 56 endodontists. The email explained the study's methods and assured that participants' identities and information given would remain anonymous and confidential. A reminder email was sent after eight weeks. Responses were collected and data were analyzed using the Chi-square test at p = 0.05. Results: The majority of respondents (86.3%) would deal with NPAAA cases "differently" from vital-pulp ones (p < 0.001). More endodontists (40%) used two or three irrgants than GDPs (29.5%). Whilst the highest proportion of endodontists (29.7%) rarely prescribed antibiotics, the highest proportion of GDPs (26%) generally did so (p < 0.001). Whilst the highest proportion of GDPs (26.9%) over-instrumented the largest canal in the first visit, most endodontists (56.8%) performed complete cleaning & shaping (C&S) (p < 0.001). In cases of non-stopped exudates, whilst the highest proportions of endodontists would either let the patient wait till the exudates significantly reduce then continue their intended approach (40.5%) or insert ICMs and temporize the tooth (40.5%), the highest proportion of GDPs (30.8%) would insert only dry cotton pellet without temporizing the tooth (p = 0.002). Of those who would leave the tooth open if non-stopped exudates presents in the first visit, the majority (81.9%) would temporize the tooth if little exudates present after C&S (p < 0.001). Conclusions: Clinicians, especially GDPs, opted to treat teeth involved in NPAAA differently from those with vital-pulp, such as: were using different ICMs and irrigants, C&S to different apical size preparation. GDPs should improve their practice by implementing multi-irrigants protocol while C&S, limit prescribing antibiotics, perform complete debridement of the root canal system and not to leave the tooth open between visits. Clinicians, especially GDPs, relied on their own experiences in managing NPAA cases which necessitates scientific-based guidelines. [ABSTRACT FROM AUTHOR]