Investigation of the efficacy of different Ni-Ti systems on acrylic blocks for correcting ledge formation.

BACKGROUND: The aim of this study was to compare the efficacy of K-type stainless steel hand instruments (Mani Inc. ), Fanta AF™ Ledge Correction (LC) (Fanta Dental), and Hyflex EDM (Coltene-Whaledent) for ledge correction, canal transport, centric ability, and shaping (preparation) time after an artificial ledge has been bypassed manually in highly curved canals using acrylic blocks. METHODS: Forty-two resin blocks, each with a radius of 5 mm (Endo Trainer Block, VDW) and an apical inclination of 55°, were used. Under stereomicroscope magnification, standard artificial ledges were created on acrylic blocks, and attempts were then made to eliminate them using hand instruments, FantaAF™ LC, and Hyflex EDM. Before and after images were obtained using a stereomicroscope and compared using Photoshop. RESULTS: Fanta AF™ LC and Hyflex EDM were found to be more effective for correcting ledges than hand instruments. The use of hand instruments resulted in the greatest transportation away from the canal curvature in the apical area. The canal shaping was completed in the shortest amount of time using Fanta AF™ LC, followed by HyFlex EDM and then the hand instruments. CONCLUSION: In terms of centric ability, the order from best to worst is as follows: Fanta AF™ LC, Hyflex EDM, and hand instruments. After the ledge was manually bypassed with hand instruments in the root canals, Hyflex EDM and Fanta AF™ LC were found to be more effective than hand instruments in reshaping the previously unreachable region between the ledge and the foramen apical.

Comparison of mechanical resistance and standardisation between original brand and replica-like endodontic systems.

This study compared the original (ProTaper Next and Reciproc) endodontic systems with their replica-like brands (X File and Only One File) in terms of standardisation, design, phase-transformation behaviour, composition and mechanical behaviour. X File showed greater taper values than ProTaper Next, while Only One File had the greatest tip diameter. Both replica-like files had an active tip and greater dimensions than their reports. There were also significant differences between the original and replica-like systems in terms of their phase-transformation behaviour and the precision of the measurement lines. Only One File showed significantly lower cyclic fatigue and torsional resistance than Reciproc (p < 0.05). There were no significant differences in the cyclic fatigue, torsional resistance and composition of NiTi between X File and ProTaper Next (p > 0.05). Although replica systems show mechanical properties that can be acceptable, they are not consistent in terms of standardisation and design.

Scanning electron microscopy analysis of conventional and controlled-memory nickel titanium files before and after multi-uses in root canals.

The current study aimed to examine changes in the physical properties of conventional and CM nickel-titanium instruments after repeated clinical use, disinfection-sterilization processes, using scanning electron microscopy (SEM). Sixty extracted mandibular molar mesial roots were used in this ex vivo study. The 60 teeth underwent final apical shaping (#25/.06) by the Revo-S SU (Revo-S Group: #25/.06; Micromega; n = 10) and Hyflex CM (Hyflex CM group: #25/.06; Coltene-Whaledent; n = 10) groups. One instrument of each group was used to shape six different teeth (Revo-S SU in 3 MB and 3 ML canals, and Hyflex CM in 3 MB and 3 ML canals), sequentially. The physical changes evident on the surfaces of the files after sequential use and sterilization processes were analyzed by SEM after the first, third, and sixth use. The first SEM examination was performed immediately after removal from the packages. Following first SEM examination, the files were sterilized before the first use as would be customary in practice. Qualitative evaluations were made by two evaluators, according to the following criteria: tip deformation, cutting edge deformation, debris, and microfracture. Revo-S showed a significant difference in cutting edge deformation, tip deformation, and microcrack formation, as compared to Hyflex CM. There was no significant difference between the groups in debris with the increasing number of uses. In this study, Hyflex CM (CM nickel-titanium) files showed better performance in terms of deformation and microcrack formation as the number of uses increased than did Revo-S (conventional nickel-titanium) files.

Influence of root canal filling techniques on sealer penetration and gutta percha/sealer ratio: a confocal laser scanning microscopy analysis / Influência das técnicas de obturação do canal radicular na penetração do cimento e na relação guta-percha / cimento: uma análise por microscopia de varredura confocal a laser

Objective: The influence of four root canal filling techniques on the penetration of an endodontic sealer into dentinal tubules and the gutta percha/ sealer ratio (GP/SR) in root canals was evaluated using confocal laser scanning microscopy (CLSM). Material and Methods: Roots of the maxillary central incisors (n=40) were prepared with ProTaper Universal files up to file F5 and assigned to five groups: continuous wave condensation, lateral condensation, single cone, Thermafill®, and negative control group. After root canal filling with gutta-percha and AH26, along with the addition of 0.01% fluorescein, the roots were cut into 2-mm slices. Using CLSM, the specimens were transversely sectioned at 3, 6, and 10 mm from the apex. Results: Sealer penetration was deeper and more frequent at 10 mm than at the 6mm and 3mm for all obturation technique. Penetration was not significantly affected by obturation techniques except single master cone tecnique. Single cone technique demonstrated the lowest sealer penetration at all levels. However, sealer thickness was strongly dependent on obturation technique. Termafill® demostrated superior GP ratio followed by continuous wave condensation, lateral condensation and single cone. Conclusion: In conclusion, the single cone technique resulted in lower sealer penetration than the other techniques, which did not differ significantly from each other. However, sealer thickness was strongly dependent on obturation technique. Termafill® demostrated superior GP ratio followed by continuous wave condensation, lateral condensation and single cone. (AU)

Objetivo: A influência de quatro técnicas de obturação do canal radicular na penetração de um cimento endodôntico nos túbulos dentinários e a relação gutapercha / cimento (GP / CIM) em canais radiculares foram avaliadas por microscopia de varredura confocal a laser (MVCL). Material e Métodos: As raízes de incisivos centrais superiores (n = 40) foram preparadas com limas ProTaper Universal até a lima F5 e distribuídas em cinco grupos: condensação de onda contínua, condensação lateral, cone único, Thermafill® e grupo de controle negativo. Após o preenchimento do canal radicular com guta-percha e AH26, juntamente com a adição de 0,01% de fluoresceína, as raízes foram cortadas em fatias de 2 mm. Usando MVCL, as amostras foram seccionadas transversalmente a 3, 6 e 10 mm do ápice. Resultados: A penetração do cimento foi mais profunda e mais frequente em 10 mm do que nos 6 mm e 3 mm para todas as técnicas de obturação. A penetração não foi significativamente afetada pelas técnicas de obturação, exceto pela técnica de cone mestre único. A técnica de cone único demonstrou a menor penetração do cimento em todos os níveis. No entanto, a espessura do cimento foi fortemente dependente da técnica de obturação. O Termafill® demonstrou uma relação superior de GP, seguida por condensação de onda contínua, condensação lateral e cone único. Conclusão: Em conclusão, a técnica de cone único resultou em menor penetração do cimento do que as outras técnicas, que não diferiram significativamente uma da outra. No entanto, a espessura do cimento foi fortemente dependente da técnica de obturação. O Termafill® demonstrou uma relação superior de GP, seguida por condensação contínua das ondas, condensação lateral e cone único. (AU)

Influence of Post Space Preparation on the Apical Leakage of Calamus, Single-Cone and Cold Lateral Condensation Obturation Techniques: A Computerized Fluid Filtration Study.

PURPOSE: Apical microleakage between the root canal and periapical tissues is considered a common cause of endodontic failure. The aim of this study was to evaluate the apical microleakage of various obturation techniques after immediate post space preparations with different drills. MATERIALS AND METHODS: One hundred twenty human single-rooted teeth were selected for this study. The coronal portions were removed to achieve a uniform length of 15 mm. All root canals were instrumented with ProTaper Next rotary files using crown-down technique. The 120 roots were randomly assigned to 3 experimental groups according to obturation technique (n = 40). The root canals were obturated with lateral condensation in group 1, single-cone technique in group 2, and Calamus 3D obturation system in group 3. Each group was divided into two subgroups (n = 20) according to drill types (Gates Glidden and Peeso drills) leaving 5 mm of apical gutta-percha. The apical microleakage was measured using the computerized fluid filtration meter method. The results were evaluated using Kruskal-Wallis test with Bonferroni Corrected Mann-Whitney U multiple comparison post hoc tests. RESULTS: There was no statistically significant difference between obturation techniques after post space preparation with Peeso drills (p > 0.05). In Gates Glidden drill groups, single-cone technique demonstrated higher leakage (0.0051 ± 0.0037 µl x min-1 × cmH2 O-1 ) than Calamus techniques (0.0019 ± 0.0012 µl x min-1 × cmH2 O-1 ) (p < 0.017). CONCLUSIONS: Gates Glidden drills caused the highest apical leakage in teeth obturated with single-cone technique.

Comparison of different final irrigant agitation techniques for the removal of Enterococcus faecalis biofilms from root canals: an in vitro study / Comparação de diferentes técnicas finais de agitação de irrigantes para a remoção de biofilmes de Enterococcus faecalis de canais radiculares: estudo in vitro

Objective: The aim of this in vitro study was to compare the effectiveness of different final irrigant agitation techniques in the removal of Enterococcus faecalis biofilms from root canals. Material and Methods: In total, the root canals of 85 extracted single-rooted human maxillary incisors teeth were prepared using the Revo-S system to a 40/06 size. The apical foramen of each tooth was sealed by light-cured resin composite material to obstruct bacterial leakage. The specimens were sterilized in an autoclave at 121°C for 15 min and stored until further use. All teeth except five (negative control group) were inoculated with Enterococcus faecalis and incubated in a CO2 chamber at 37°C for 7 days; the trypticase soy broth was changed every 2 days. For the determination of possible biofilm formation, five of the 80 teeth were randomly selected as a positive control group; one tooth of positive control group was analysed for biofilm development by scanning electron microscope (SEM) and these teeth received no final irrigant agitation procedure. Then, the remaining 75 teeth were randomly divided into five test groups (n=15 each) and were sequentially irrigated with 5% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid and 5% NaOCl. Following each irrigant application, different final irrigant agitation techniques were introduced for 60 s (3×20-s sessions). Group 1 received manual­ dynamic agitation, group 2 received passive ultrasonic agitation (PUI), group 3 received EndoActivator agitation, group 4 received photoninitiated photoacoustic streaming (PIPS) with the Er:YAG laser and group 5 received conventional syringe irrigation. Colony-forming units (CFUs) were counted in samples from the positive control and test groups. Data were analysed using Kruskal­ Wallis and post-hoc Mann­Whitney U multiple comparison tests. Results: E. faecalis elimination was significantly better in the experimental groups than in the positive control groups (p < 0.001). Manual­dynamic agitation and conventional syringe irrigation, with no significant differences between the two groups. Conclusion: Essentially, CFU reduction was significantly greater in the PUI, EndoActivator and PIPS groups than in the manual­dynamic agitation and conventional syringe irrigation groups (p <0.001) , with no significant differences among the former three groups. (AU)

Objetivo: O objetivo deste estudo in vitro foi comparar a eficácia de diferentes técnicas finais de agitação de irrigantes na remoção de biofilmes de Enterococcus faecalis de canais radiculares. Material e Métodos: No total, os canais radiculares de 85 dentes incisivos superiores unirradiculares humanos extraídos foram preparados usando o sistema Revo-S para um tamanho 40/06. O forame apical de cada dente foi selado por material compósito de resina fotopolimerizável para obstruir o vazamento bacteriano. Os espécimes foram esterilizados em autoclave a 121 ° C por 15 min e armazenados até uso posterior. Todos os dentes, exceto cinco (grupo controle negativo), foram inoculados com Enterococcus faecalis e incubados em câmara de CO2 a 37 ° C por 7 dias; o caldo de soja tripticase foi trocado a cada 2 dias. Para a determinação da possível formação de biofilme, cinco dos 80 dentes foram selecionados aleatoriamente como grupo controle positivo; um dos dentes do grupo controle positivo foi analisado para o desenvolvimento do biofilme por microscopia eletrônica de varredura (MEV) e estes dentes não receberam nenhum procedimento final de agitação irrigante. Em seguida, os 75 dentes restantes foram aleatoriamente divididos em cinco gruposteste (n = 15 cada) e irrigados sequencialmente com hipoclorito de sódio a 5% (NaOCl), ácido etilenodiaminotetracético a 17% e NaOCl a 5%. Após cada aplicação de irrigantes, diferentes técnicas finais de agitação foram introduzidas por 60 s (3 x 20 s sessões). Grupo 1 recebeu agitação manual-dinâmica, grupo 2 recebeu agitação ultra-sônica passiva (PUI), grupo 3 recebeu agitação EndoActivator, grupo 4 recebeu fotoacústica iniciada por fóton (PIPS) com o laser Er: YAG e grupo 5 recebeu irrigação convencional com seringa. As unidades formadoras de colônia (CFUs) foram contadas em amostras dos grupos controle positivo e teste. Os dados foram analisados utilizando testes de comparação múltipla Kruskal-Wallis e post-hoc Mann-Whitney U. Resultados: A eliminação de E. faecalis foi significativamente melhor nos grupos experimentais do que nos grupos de controle positivo (p < 0,001). Agitação manual-dinâmica e irrigação com seringa convencional, sem diferenças significativas entre os dois grupos. Conclusão: Essencialmente, a redução de UFC foi significativamente maior nos grupos PUI, EndoActivator e PIPS do que nos grupos de agitação manual-dinâmica e de seringa convencional (p < 0,001), sem diferenças significativas entre os três grupos anteriores (AU)

Treatment approaches and antibiotic use for emergency dental treatment in Turkey.

The purpose of this study was to gather information about Turkish general dental practitioners' treatment approaches towards endodontic emergencies, antibiotic-prescribing habits, and their participation in lifelong learning programs. Questionnaires were given to dentists who attended the 16th National Congress organized by the Turkish Dental Association. From 1,400 questionnaires distributed, 589 (43%) were deemed usable in this study. This survey dealt with questions that were subdivided into two main topics: dental emergency treatment approaches, and antibiotic prescription and information on lifelong learning program participation. The statistical analysis was conducted with a χ (2) test at a significance level of P<0.05. For irreversible pulpitis cases in vital teeth, most of the dental practitioners (65.3%) preferred single-visit root canal treatments. For teeth presenting a periapical lesion, the preferred treatment approach was root canal treatment (91.5%). The rate of prescription of analgesics and antibiotics was 21.7% in untreated acute apical periodontitis cases and 41% in acute apical abscess cases. Frequently prescribed antibiotics were amoxicillin-clavulanate (61.8%) and amoxicillin (46.5%). There was a tendency for practitioners to attend congresses as their years of professional practice increased (P<0.0001). There have been discrepancies between taught and observed practice. Educational initiatives are needed to prevent inappropriate prescription of antibiotics.

The location and accessibility of the second mesiobuccal canal in maxillary first molar.

OBJECTIVES: The purpose of this study was to examine the location and accessibility of the second mesibuccal canal in maxillary first molar of a Turkish sub-population. METHODS: Presence and accessibility of the MB2 canal in 110 extracted maxillary first molars was examined with unaided vision, dental loups and the DOM. To characterize the geometrical location of MB2 canals, photographs of pulp chambers were obtained. RESULTS: With the unaided vision, 58 MB2 canal orifices and after evaluation with the dental loup, DOM an additional 28 MB2 canal orifices were detected. In 65 molars, the MB2 canal orifices was located 0.87 mm distally and 1.73 mm palatally to the main mesiobuccal canal and in the remaining 21 molars was 0.72 mm mesially and 1.86 mm palatally. CONCLUSIONS: Presence of second mesiobuccal canal was similar to the other studies but in a Turkish sub-population it originates mainly distal to the main MB canal.

Management of the perforations due to miniplate application.

Microdimensioned osteosynthesis using miniplates has been common practice in maxillofacial surgery. However, tooth injury during the application of the miniplates have been reported in few papers. In this case, a 32-yr-old female patient, whose two teeth were necrosed because of the perforation during screw insertion was presented. The reason of the perforations during the rigid internal fixation was the lack of radiographic assessment because of the pregnancy. Maxillary right first premolar and maxillary left canine were perforated and necrosed because of the screw insertion. The necrosed teeth were detected 1 yr after the rigid internal fixation. The root canals of nonvital teeth were filed using step-down approach. Cold lateral condensation of gutta-percha was used to fill the canals. Six-month recall visits were scheduled and there was no problem after 2-yr follow-up period.

Comparative evaluation of the preparation efficacies of HERO Shaper and Nitiflex root canal instruments in curved root canals.

OBJECTIVES: To comparatively evaluate the shaping efficacies of HERO Shaper rotary instruments and Nitiflex hand files. STUDY DESIGN: The mesial roots of 40 mandibular molars were used. In 20 teeth, the mesiobuccal canals were instrumented with HERO Shaper and the mesiolingual canals with Nitiflex. In the remaining 20 teeth, the mesiobuccal canals were instrumented with Nitiflex and the mesiolingual canals with HERO Shaper. Pre- and postoperative sections were obtained from the coronal, middle, and apical portions and analyzed. Statistical analysis was performed using the Student t test. RESULTS: More dentin was removed from the middle portion with HERO Shaper (P < .05). No statistically significant difference was observed in terms of transportation (P>.05). No instrument fracture or deformation was noted. CONCLUSIONS: Both HERO Shaper and Nitiflex can be recommended for clinical practice. Further studies can focus on the comparison of HERO Shaper with other rotary instruments as there is an increasing trend for the utilization of these systems.

Efficacy of various concentrations of citric acid at different pH values for smear layer removal.

OBJECTIVE: The efficacy of various concentrations of citric acid at different pH values for the removal of the superficial smear layer from dentinal surfaces was examined through the use of scanning electron microscopy. Study design Fifty extracted teeth were irrigated with sodium hypochlorite (NaOCl) during instrumentation. Citric acid solutions at 50%, 25%, 10%, and 5% (wt/vol) concentrations were prepared. In addition, similar solutions of citric acid were buffered to pH 6. Citric acid solutions with original and buffered pH values were used as final rinses. Bidistilled water and NaOCl were used as controls. The data were analyzed by using nonparametric Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Lower concentrations with lower pH values removed smear layer more efficiently than the ones with higher pH values (P <.05), whereas no significant differences for higher concentrations were detected between low and high pH values. However, more destruction of peritubular dentin was observed at higher concentrations with low pH values. CONCLUSION: Within the limits of this study, lower concentrations of citric acid with its original pH were found to be as effective as higher concentrations in the removal of superficial smear layer.

Bilateral oroantral fistulas following devitalization of teeth by arsenic trioxide: a case report.

Although it is well known that prolonged application or leakage of arsenic trioxide can cause severe damage to the periodontal tissues, the substance is still used by some dentists. This paper describes a case of arsenical necrosis of the jaws affecting the right and the left side of the maxilla. As a result of leakage into the tissues of an arsenical paste from the pulp chamber of endodontically treated teeth, bilateral oroantral fistula (OAF) occurred. It is concluded that there is no justification, whatsoever, for the use of arsenic in modern dental practice. In the following case, buccal advancement flap and submucosal palatal island flap techniques were used for to close the OAF. The submucosal palatal island flap technique resulted in successful closure of the OAF.