Efficiency of the new reciprocating and rotary systems with or without ultrasonics in removing root-canals filling with calcium silicate-based sealer (MTA).

BACKGROUND: To compare the efficiency of endodontic rotary and reciprocating systems in removing calcium silicate-sealer based fillings and to investigate the impact of passive ultrasonic irrigation (PUI) on their efficiency. MATERIALS AND METHODS: 160 root-canals were instrumented, filled with gutta-percha and calcium silicate based-sealer and divided into 10 equal groups. Five groups in which the reciprocating systems (WaveOne-Gold, Reciproc-Blue and R-Motion) and rotary systems (Fanta-AF-One and Tango-Endo) were used to remove root-canals' fillings. In the other five groups the fillings were removed by the same systems then additionally with PUI. The times to complete retreatments procedures were recorded. Micro-computed tomography's analysis of the root-canals fillings' volume before and after retreatments was used to determine the remaining filling materials (RFMs) volumes. RESULTS: The RFMs after using rotary systems (10.1%) was greater than after using reciprocating systems (3.8%) (P < 0.001). The RFMs after using WOG (2%) and RB systems (2.6%) were less than those in the RM (6.8%), TE (9.5%) and FAFO (10.7%) systems [P < 0.05]. The times required to remove the filling materials using the TE (3.7 min), FAFO (4.1 min) and RM (4.1 min) systems were shorter than those required by the RB (5.4 min) and WOG (4.9 min) systems [P < 0.05]. Using PUI resulted in less RFMs (1.44%) when compared to using only rotary or reciprocating systems (6.27%) [P < 0.001]. CONCLUSIONS: Endodontic reciprocation systems were more effective, but needed longer times than rotary systems in removing calcium silicate based- sealers fillings. The PUI significantly improved removal of the root-canals' filling materials. CLINICAL RELEVANCE: Reciprocating systems and PUI are recommended whenever root-canals retreatment is considered regardless of using calcium silicate-based sealers.

Efficiency of reciprocating systems reciprocated at different angles in removing root-canals fillings with an MTA-type sealer: an Ex-vivo study.

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.

Management of an over-extruded fragment in a C-shaped root canal configuration: A case report and literature review.

Separation of root canal instruments is a common incident during root canal treatments' procedures. The complex configuration of root canal systems is one of the most influencing factors, not only during the occurrence of instrument separation but also during the management of such unpleasant incidents. There are few reports on the management of fractured instruments located in the apical third of the root canals apical, especially those extruded beyond the apex. A 37-year-old woman was referred to an endodontic specialist to complete a root canal treatment after the separation of an endodontic file in the middle-third of the C-shaped root canal configuration (Vertucci type II) of the mandibular second molar. A failed attempt at managing the fragment by the dentist resulted in the backward placement of the fragment, which was more apically, and partial extrusion beyond the root apex. The fractured instrument was successfully and safely retrieved using different procedures and techniques including bypassing the fragment, loosening the fragment using ultrasonics and then removing it by the crab-claw shaped tweezers (Zumax broken instruments removal kit). This case report demonstrates the importance of high magnification provided by the dental operating microscopes and sound clinical skills and judgment, especially in assessing the difficulty of cases that is necessary for various treatment approaches. In addition, the availability of different armamentaria to manage separated instruments is essential. Finally, this case report proposes and advocates the idea of removing fractured instruments extruding beyond the apex without surgery.

Implementation of Digital Radiography during Root Canal Treatments in Saudi Endodontic and General Dental Practice.

Objective: To report usage of full-digital-radiography (FDR) during root-canal-treatments (RCTs) in Saudi dental-practice and to explore factors and measures that obstacle/contribute to better implementation. Methods: Following a pilot study, questions on demography, types of radiographic systems used during RCTs, advantages and disadvantages of FDR, reasons of not using it and measures that increase its implementation were included. The sample size was calculated considering the total number of general dentists (GDs) in Saudi Arabia and a 50-60% expected response rate. The questionnaire was emailed to 550 GDs and all endodontists in Saudi Arabia (185). A solo a reminder was emailed two months later. Data were analyzed by the Chi-square test at P=0.05. Results: Most participants (64.9%) used FDR for RCTs (P<0.001); with all endodontists (100%) and 52% of GDs (P<0.001). While all who were working in governmental-academia (100%) used FDR, 69.2% in private-academia did so (P<0.001); with no difference between private and governmental-clinics (60.6 and 69.2%). As the weekly-performed RCTs increased and participants' experience decreased, FDR usage increased (P<0.05). While high-cost was the main FDR disadvantage, faster-workflow, better image-quality and less-radiation were the main advantages (P<0.001). The majority (76.1%) of FDR none-users were doing so because of unavailability. Participants reported lower-cost and better undergraduate-education as most effective measures that increase FDR implementation in dental-practice. Conclusion: FDR was adopted to good extent in Saudi dental-practice. Financial aspects were the main concern that should be addressed to increase FDR implementation in private practice. Endodontists showed better perception towards FDR and suggested more attention to educational aspects.

Usage of Image-Enhancement Tools When Reading Radiographs Taken During Root-Canals Treatments' Procedures.

Objective: This study aimed at exploring the usage of radiographic image-enhancement tools in Saudi dental practice when interpreting radiographs taken for root-canal-treatments' (RCTs) procedures and the influencing factors. Methods: An online survey including questions related mainly to the usage of images enhancement tools and the reasons for no or low frequently usage was constructed. The survey was sent to 550 general dentists (GDs), randomly selected from the Saudi Dental Register, and all endodontists (185) in Saudi Arabia using the Google-Drive tool. A reminder email was sent two months later to encourage none-respondents to complete the survey. Data were analyzed using the Chi-square and Linear-by-Linear Association tests at p=0.05. Results: While the highest percentage of GDs (48.3%) never used the colour-coded tool, the highest percentage of endodontists (46.1%) used it sometimes (P<0.001). The majority (84.2%) used the contrast tool either generally (67.8%) or sometimes (16.4%) (P<0.001); with more endodontists (77.55%) than GDs (63.1%) (P=0.011). As participants experience decreased and the weekly performed cases increased, the trend of using this tool increased (P<0.05). While most GDs (67.6%) either never (46%) or few-times (21.6%) used the highlight tool, most endodontists (56.9%) either used it generally (34.4%) or sometimes (22.5%) (P<0.001). The majority (82.3%) were using the magnification tool either generally (55.1%) or sometimes (27.2%). The highest percentage (36.1%) was generally using the negative-view tool (P=0.045); with more endodontists (63.7%) than GDs (20.8%) (P<0.001). While "I don't know how to use it" was the dominant reason reported by GDs for not using most of the tools, lack of time was the dominant reason reported by endodontists (P≤0.001). Conclusion: The contrast and magnification were the most common used image-enhancement tools in Saudi dental practice. Endodontists reported greater preferences on using all images-enhancement tools than GDs. Unawareness and lack of time were the dominant reasons for not using the tools reported by GDs and endodontists, respectively. Further studies are required to determine the exact application for each tool and to investigate the impact of all image-enhancement tools on their diagnostic accuracy.

Factors influencing incidents of complications while using nickel-titanium rotary instruments for root canal treatment.

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' fracture at 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.

A Comparative ex-vivo Study of Effects of Different Irrigation Protocols with/without Laser Activation on the Root Dentine's Micro-Hardness.

OBJECTIVE: To compare the effects of different irrigation protocols, with/without laser activation, on the radicular dentine's micro-hardness. METHODS: Eighty-two human extracted premolars were decoronated and divided into 7 groups. Roots were longitudinally split into two halves. The micro-hardness was measured for one half before and after irrigation protocols. The groups were; G1: MTAD without laser-activation, G2: MTAD with laser-activation, G3: sodium-hypochlorite (SH) with laser-activation, G4: SH then EDTA with laser-activation, G5: SH then MTAD with laser-activation, G6: SH without laser-activation. G7: distilled water (control). In the two-irrigants groups G4 and G5), samples were irrigated first with SH then with MTAD or EDTA irrigants, which were activated by the laser. The difference between the before- and after-irrigation micro-hardness was calculated to obtain the micro-hardness difference. Data were analyzed using the Paired Sample-t and Two-ways ANOVA tests at P=0.05. RESULTS: Overall, the mean dentine's micro-hardness after-irrigation (103.1) was lower than before-irrigation (116.1) (P<0.001); except for the distilled-water group, (116.6 and 112.9, respectively) (P=0.075). The micro-hardness reduction of SH without laser-activation group (32.5) was the greatest (P<0.001). The single-irrigant or laser-activation irrigation protocols caused significantly less micro-hardness reduction compared to the two-irrigants or no laser-activation protocols. The mean micro-hardness reduction of SH and MTAD groups (both with laser-activation) (5.8 and 9.3, respectively) were significantly lower than other groups, but not from that of the control group (3.7). CONCLUSION: Using irrigants significantly reduced the root-dentine's micro-hardness. Although irrigants agitation by an Er: Yag laser significantly minimized micro-hardness reduction, it did not suppress the adverse effects on dentine micro-hardness when two-irrigants were used.

Modalities of using endodontic nickel-titanium rotary instruments and factors influencing their implementation in dental practice.

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.

Preferences of dentists and endodontists, in Saudi Arabia, on management of necrotic pulp with acute apical abscess.

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.

The efficacy of retreatment and new reciprocating systems in removing a gutta-percha-based filling material.

OBJECTIVES: To investigate the efficacy of retreatment and reciprocating rotary systems in removing gutta-percha filling material from root-canal systems. METHODS: A total of 90 single-canal human teeth were instrumented using a F3 ProTaper file and obturated with gutta-percha and the Tubliseal sealer using the lateral-compaction technique. They were divided into five groups according to the rotary system used to remove the filling material: Reciproc, which used the Reciproc-R25 file; WaveOne, which used the WaveOne-Primary file; S1, which used the S1 (25/.06) file; ProTaper-R, which used the ProTaper-Retreatment system; and Mtwo-R, which used the Mtwo®-Retreatment system. The time required to remove the filling material (min) and the associated instrument separation, if any, were recorded. Teeth were cleaved longitudinally and photographed with a high-resolution camera. Images were imported to the AutoCAD application to measure the remaining filling material and the root-canal space. Data were analysed using the one-way analysis of variance and Chi-squared tests. RESULTS: The Mtwo-R group showed the highest mean remaining filling material (51%) (p < 0.001), with no significant differences among the other groups. The ProTaper group required the least time for filling-material removal (4.95 min), with significant differences compared to the other groups (p < 0.05), except the WaveOne group (5.83 min; p = 1.000). Overall, 13 instruments (15.9%) were used for filling-material removal, with a significantly greater proportion in the Mtwo-R group (33.3%) compared to the other groups (p = 0.009). CONCLUSIONS: Within the limitations of this in vitro study, reciprocating rotary systems were as effective as retreatment rotary systems in removing root-canal filling material. The Mtwo-R system showed the poorest performance with respect to removal effectiveness and instrument separation.

Preference and usage of intracanal medications during endodontic treatment.

OBJECTIVES: To investigate the preferences of general dental practitioners (GDPs) and endodontists in using endodontic intra-canal medications (ICMs). METHODS: This observational and descriptive study was conducted in 2014 in the western province of Saudi Arabia. Following ethical clearance and 2 pilot studies, a web-based questionnaire was electronically sent to 375 randomly and systematically selected GDPs and all endodontists in the western province (n=49). An accompanying e-mail explained the study's aims and confirmed that the data yielded would remain confidential. The responses were collected, and the data was analyzed using the Chi-square test at p=0.05. RESULTS: Significantly, the highest proportion of respondents (53.7%) reported disinfection of the root canals as the main function of ICMs. Calcium hydroxide (CH) was the preferred material of the majority of those who used the same ICM in all cases (85.7%). While the vast majority of all endodontists (87.5%) used CH after pulp extirpation, 48.5% of GDPs used formocresol (p less than 0.001). Almost 30% of those who used ICMs after pulp extirpation did not do so after cleaning and shaping of vital cases. Most endodontists used CH (62.5%) and antibiotics (37.5%) in necrotic pulp cases without apical lesions, which were significantly greater than those of GDPs who did the same (43.8% and 17.2%). CONCLUSIONS: Participants were aware that the main function of ICMs is disinfection of the root canal system. However, it is clear that GDPs should reduce their reliance on phenol- and formaldehyde-based medications. There was a distinct trend toward the use of ICMs, especially CH, in necrotic pulp cases.

Multidisciplinary management of concomitant pulpal and periodontal lesion: A case report.

In this case report, the management of a concomitant endodontic-periodontal lesion case is described. A 31-year-old patient presented with symptomatic apical periodontitis of tooth #36 due to failed endodontic treatment and a generalized aggressive periodontitis. Following full-mouth scaling and root-planing, a root-canal retreatment (tooth #36) was initiated. While the distal and mesio-buccal canals were successfully treated, a transportation perforation of the mesio-lingual canal occurred and was repaired by the MTA. An apical microsurgery of the mesial root combined with surgical periodontal debridement for the lower left quadrant was performed. Three weeks later, resective and regenerative periodontal surgeries of the other 3 quadrants were accomplished. Because of the 6-month post-operative healing, the regenerative periodontal surgery for the lower-left quadrant was performed. The 6-month post-operative recall showed complete healing of the mesial root lesion and reduction of the distal root lesion. The multidisciplinary approach and advanced armamentarium contributed to favourable outcome.

Why dentists don't use rubber dam during endodontics and how to promote its usage?

BACKGROUND: This survey study aimed at investigating the frequency of rubber dam use during root canal treatment, identifying influencing factors for not using it by Saudi general dental practitioners (GDPs) and endodontists. It also aimed at identifying measures that increase rubber dam usage. METHODS: After obtaining an ethical approval, two pilot studies were conducted on staff members at Taibah University College of Dentistry and a group of GDPs. A final online survey was constructed comprising 17 close-ended questions divided into six categories: demographics, endodontic practice, rubber dam use, alternative isolation methods, reasons for not using rubber dam, and measures and policies that increase its usage. The survey was emailed to 375 GDPs randomly selected from the dental register and all endodontists (n = 53) working in the western province, Saudi Arabia. Data were analyzed using the Chi-square and Linear-by-Linear association tests at p ≤ 0.05. RESULTS: The proportion of endodontists who used rubber dam (84.8 %) was significantly greater than that of GDPs (21.6 %) (p < 0.001). Significantly the highest proportion (40.5 %) did not use rubber dam because of unavailability at working place. Most rubber dam none-users (69.25 %) used a combination of other isolation means. The highest proportion of those who used rubber dam were working in the governmental sector (54.3 %). Among rubber dam users, the greatest proportion graduated from Saudi Arabia (57.8 %) compared to those graduated from Egypt (34.3 %) and Syria (22.4 %). There was a significant correlation between the patterns of rubber dam use during undergraduate training and its usage after graduation (p = 0.001). The highest proportion of participants (48.1 %) reported better undergraduate education as the most important factor that would increase rubber dam use in dental practice. CONCLUSIONS: Using of rubber dam was not common in Saudi general dental practice. Dentists must follow the recommended standards of care. Place of work and patterns of using rubber dam during undergraduate study were the most influencing factors. Better undergraduate education was the most important proposed measure to increase its usage. The combination of cotton rolls and saliva high-volume ejector or gauze was the most common alternative to rubber dam isolation.

Management of intracanal separated instruments.

INTRODUCTION: Intracanal separation of endodontic instruments may hinder cleaning and shaping procedures within the root canal system, with a potential impact on the outcome of treatment. The purposes of this narrative review of separated instruments were to (1) review the literature regarding treatment options, influencing factors, and complications and (2) suggest a decision-making process for their management. METHODS: An online search was conducted in peer-review journals listed in PubMed to retrieve clinical and experimental studies, case reports, and review articles by using the following key words: instruments, files, obstructions, fractured, separated, broken, removal, retrieval, management, bypassing, and complications with or without root canal and endodontic. RESULTS: There is a lack of high-level evidence on management of separated instruments. Conventional conservative management includes removal of or bypassing the fragment or filling the root canal system to the coronal level of the fragment. A surgical intervention remains an alternative approach. These approaches are influenced by a number of factors and may be associated with complications. On the basis of current clinical evidence, a decision-making process for management is suggested. CONCLUSIONS: Guidelines for management of intracanal separated instruments have not been formulated. Decisions on management should consider the following: (1) the constraints of the root canal accommodating the fragment, (2) the stage of root canal preparation at which the instrument separated, (3) the expertise of the clinician, (4) the armamentaria available, (5) the potential complications of the treatment approach adopted, and (6) the strategic importance of the tooth involved and the presence/or absence of periapical pathosis. Clinical experience and understanding of these influencing factors as well as the ability to make a balanced decision are essential.

Efficiency of a newly designed ultrasonic unit and tips in reducing temperature rise on root surface during the removal of fractured files.

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 degrees C) with the air flow active was significantly lower than that with nonactive air flow (11 degrees C). At 10- and 15-psi pressures, the temperature rise after 120 seconds induced by ET40D tips was 4 degrees and 2.4 degrees C, respectively. These were significantly lower than with CPR5 tips (6.3 degrees and 4.2 degrees 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.

A microcomputed tomography scanning study of root canal space: changes after the ultrasonic removal of fractured files.

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.

Factors affecting temperature rise on the external root surface during ultrasonic retrieval of intracanal separated files.

Temperature rise (TR) on the external root surface during ultrasonic removal of separated files (SFs) from 50 lower incisors roots of 10-mm length was investigated. CPR ultrasonic tips (Obtura-Spartan, Fenton, MO) were used dry to retrieve F2 ProTaper (Dentsply, Surrey, UK) segments fractured 2.5 mm from the coronal access in five groups: CPR2, CPR5, and CPR6 at power setting 1 and CPR5 at power settings 2.5 and 5. Temperature changes were inspected at 30-second intervals up to 120 seconds at three different sites: two at mesiodistal and buccolingual surfaces adjacent to the most coronal aspect of the SF and the third adjacent to the most apical aspect. Overall, the highest mean TR was at the buccolingual root surface followed by that at the mesiodistal and the more apical site surfaces. At power setting 1, CPR6 produced a significantly lower TR than CPR5, and both can be used for 120 and 60 seconds, respectively. Power setting 5 is not recommended for the removal of SF because this induces a hazardous TR.