The top 10 most-cited articles on the management of fractured instruments: a bibliometric analysis

OBJECTIVES: The purpose of this research was to identify the top 10 most-cited articles on the management of fractured or broken instruments and to perform a bibliometric analysis thereof. MATERIALS AND METHODS: Published articles related to fractured instruments were screened from online databases, such as Web of Science, Scopus, PubMed, and ScienceDirect, and highly cited papers, with at least 50 citations since publication, were identified. The most-cited articles were selected and analysed with regard to publication title, authorship, the journal of publication, year, institution, country of origin, article type, and number of citations. RESULTS: The top 10 most-cited articles were from various journals. Most were published in the Journal of Endodontics, followed by the International Endodontic Journal, and Dental Traumatology. The leading countries were Australia, Israel, Switzerland, the USA, and Germany, and the leading institution was the University of Melbourne. The majority of articles among the top 10 articles were clinical research studies (n = 8), followed by a basic research article and a non-systematic review article. CONCLUSIONS: This bibliometric analysis revealed interesting information about scientific progress in endodontics regarding fractured instruments. Overall, clinical research studies and basic research articles published in high-impact endodontic journals had the highest citation rates.

Histological evaluation of refinement influence in the cleaning efficacy of rotary nickel-titanium ProTaper® instruments in oval-shaped root canals

Introduction and objective: The aim of this in vitro study was to evaluate the cleaning and shaping efficacy of rotary nickel-titanium ProTaper® instrumentation in oval canals and the influence of ultrasonic irrigation on the final refinement. Material and methods: Twenty mandibular molars were accessed and divided in two groups. Only distal roots with oval canals were used. Group I was instrumented using only rotary nickel-titanium ProTaper® instruments. Group II received the same preparation followed by refinement with 3 minutes of ultrasonic passive irrigation. After preparation, the distal roots were sectioned for histological processing. Coronal, middle and apical thirds were analyzed. Uninstrumented perimeter in each third was measured by the software Image tool 3.0. Results: The percentage of uninstrumented perimeter was calculated for each third of each root and average percentage was calculated for each third in both groups. Statistical analysis was performed with t-test through the software SPSS 11.0.1 for Windows. The level of significance was set at 1%. Group I showed higher percentage of uninstrumented perimeter in all thirds. Group II, which received ultrasonic irrigation showed better results in all thirds (p < 0.01). Comparing the three thirds in the same group, no statistically significant differences were found (p > 0.05). Conclusion: Under the conditions of this ex vivo study, the three minutes use of ultrasonic irrigation after rotary instrumentation resulted in significantly more instrumented walls in the distal roots of mandibular molars.

Efficacy of five rotary systems versus manual instrumentation during endodontic retreatment

The purpose of this study was to evaluate the efficiency of ProFile, GT, ProTaper, Race and K3 rotary instruments compared with hand K-files for removal of gutta-percha during retreatment. Sixty mandibular premolars were instrumented with GT rotary files and filled by thermomechanical compaction of gutta-percha and AH Plus sealer. The teeth are randomly divided into 6 groups of 10 specimens each. The roots were split longitudinally, digital images were created using a flatbed scanner, and the areas with remaining filling material were demarcated using Image Tool 1.21 software. The results indicate that GT left significantly less (p<0.05) remaining filling material (1.18 ± 1.47) than hand (3.70 ± 3.16) and Hero instruments (2.99 ± 2.58). There was no statistically significant difference (p<0.05) among the others techniques: ProFile (1.99 ± 2.66), ProTaper (2.00 ± 1.99) and K3 (2.71 ± 2.87) when compared with GT. In conclusion, GT, ProFile, ProTaper and K3 were more effective in removing gutta-percha than manual and Hero instruments.

O propósito deste estudo foi avaliar a eficiência dos instrumentos rotatórios ProFile, GT, ProTaper, Race e K3 comparados com limas K para a remoção do material obturador durante o retratamento. Sessenta pré-molares inferiores foram instrumentados com o sistema rotatório GT e obturados usando a técnica de compactação termomecânica de guta-percha com cimento AH Plus. Os dentes foram divididos aleatoriamente em seis grupos de dez espécimes cada. As raízes foram seccionadas longitudinalmente, imagens digitais foram criadas através de um scanner, e as áreas de remanescentes de material foram medidas usando o programa Image Tool 1.21. Os resultados indicaram que o GT deixou significantemente menos material remanescente (1,18 ± 1,47) do que os instrumentos manuais (3,70 ± 3,16) e os instrumentos Hero (2,99 ± 2,58) (p<0,05). Não houve diferença estatisticamente significante entre as outras técnicas ProFile (1,99 ± 2,66), ProTaper (2,00 ± 1,99) e K3 (2,71 ± 2,87) quando comparadas com o GT. Como conclusão, GT, ProFile, ProTaper e K3 foram revelados como mais efetivos em remover a guta-percha do que os instrumentos manuais e os instrumentos Hero.

Cleaning and shaping curved root canals: Mtwo® vs ProTaper® instruments, a lab comparison.

Objectives: The purpose of this study was to compare root canal preparation in curved canals in molar teeth with the rotary NiTi Mtwo and ProTaper systems in terms of canal shape and smear layer. Materials and Methods: Mesiobuccal canals of 60 molar teeth with angles of curvature between 25 and 35 degrees were prepared with a torque controlled low speed engine; 30 canals for each system. Each individual instrument was used to prepare four root canals and the time required for preparation was recorded. Standardized radiographs were taken before and following instrumentation and used to determine changes in canal curvature. Results: There was no significant difference in preparation time between the two systems. No instruments separated during use. The Mtwo system gave a statistically smaller change in canal curvature and thus was better for maintaining the original shape of the root canal, with less transportation (P less than 0.05). The greatest difference was seen for maxillary molar teeth. When prepared root canals were examined by SEM there was no difference between the two systems at the coronal, middle or apical thirds. Conclusion: Overall, the results of this study suggest that Mtwo instruments are preferable for situations where canals are curved, particularly for maxillary molars.

A comparative study of antimicrobial efficacy of three different instruments and mechanical preparation techniques in single infected root canals / 实用口腔医学杂志

Objective: To compare and analyze the antimicrobial efficacy of three different mechanical preparation techniques in single infected root canals. Methods; Forty-five single root canals with chronic periapical periodontitis were selected. The specimens were divided into three groups randomly, 15 root canals per group. Croup A: preparation with stainless steel K-files (step-back technique), Croup B: preparation with HERO 642 NiTi rotary files (crown-down technique) and Group C: preparation with Mtwo NiTi rotary files ( modified crown-down technique). The sterile normal saline was used as irrigation. Samples were taken before and after canal preparation. The difference of CFU was calculated as well as the bacterial species. Results; All groups were effective to reduce bacteria within the infected root canals greatly(P<0.01). Croup A and Group C were statistically better than Group B(P<0.05). Group A was more effective than Group C but there was no statistically difference between them(P>0.05). Conclusion; Mechanical preparation can greatly reduce the intracanal bacteria, but can not obtain bacteria-free canals. The mechanical preparation must be aided by chemical irrigation to improve the success of root canal therapy.

Avaliação radiográfica da eficiência dediferentes instrumentos rotatórios no retratamento endodôntico / Assessment of the effectiveness of differentrotary instruments in endodontic retreatment

Objetivo: O objetivo deste estudo foi comparar in vitro a eficiência da remoção da guta-percha dos canais radiculares por meio de diferentes instrumentos rotatórios. Material e métodos: Foram utilizados 60 prémolares inferiores humanos extraídos, os quais foram manejados com os instrumentos GT até o #30 taper .04 e obturados pela técnica híbrida de Tagger. O retratamento foi realizado de acordo com os seguintes instrumentos: ProFile (grupo I), ProTaper (grupo II), GT (grupo III), manual controle (grupo IV), K3 (grupo V) e Hero (grupo VI). Radiografias no sentido vestibulolingual foram realizadas, escaneadas a uma resolução de 480 DPI e analisadas em computador de acordo com o remanescente de material obturador após o retratamento. As raízes foram divididas em terço cervical, médio e apical, e atribuíram-se escores numa escala de: 0 (sem material remanescente), 1 (até 25%), 2 (até 50%) e 3 (mais de 50%). Os escores de remanescente de material obturador para os diferentes instrumentos testados foram analisados estatisticamente por meio do teste Kruskal- Wallis. Resultados: Existiu diferença estatística entre os instrumentos (p < 0,01). O grupo instrumentado com o sistema Hero e K3 diferiram dos demais grupos, que obtiveram os melhores resultados. O grupo controle (manual), apesar de ter baixos valores juntamente com os demais, quando avaliado por terços, apresentou a maior quantidade de remanescente de material no terço apical. Conclusão: Os grupos ProFile, ProTaper, GT e manual alcançaram os melhores resultados, porém não houve diferença estatística significante entre eles.

Objective: The purpose of this study was to compare in vitro the effectiveness of removing guta-percha from root canals using differents rotatory instruments. Material and methods: Sixty human inferior premolars have been used, which were instrumented with GT hand files up to #30 taper .04 and obturated using Tagger’s hybrid technique. The retreatment has been based in the following instruments: ProFile (group I), ProTaper (group II), GT (group III), Manual-Control (group IV), K3 (group V), and Hero (group VI). Radiographies were taken in vestibular orientation, scanned at resolution 480DPI and analyzed by computer for the observation of the remnant parts of obturation materials after retreatment. The roots have been divided in 1/3 cervical, medium and apical, and scores were attributed as per the following scale: 0 (absence of remnant materials), 1 (up to 25%), 2 (up to 50%), and 3 (over 50%). The scores of obturation remnant materials for the differents tested instruments were statistically assessed by means of the Krusckal-Wallis’ method. Results: There was statistical difference among the instruments (p < 0.01). The group instrumented using Hero and K3 differed from the remaining groups, which presented best results. The control group (manual), in spite of presenting low values, as well as the remaining groups, when appraised by thirds has shown a greater quantity of remaining material at the apical third. Conclusion: The ProFile, ProTaper, GT, and Manual groups have presented more outstanding results, notwithstanding the absence of meaningful statistical difference among them.

Morphological characteristics of damaged Hero642 Ni-Ti dental files / 实用口腔医学杂志

Objective:To analyze the morphological characteristics of damaged Hero642 Ni-Ti dental files, and explain the relationship between deformation and fracture.Methods:71 discarded files were observed under naked eyes and stereomicroscope. 5 of which were observed under S360 scanning electronic microscope (SEM), and typical photos were taken for analysis.Results:The damage of Hero642 Ni-Ti dental files was characterized by fracture, tightened or loosened spiral and some kind of deformation detected at more than 35 times magnification. Under SEM, the dimple pattern was represented in the fracture surface of the files. Conclusion:Most Hero642 Ni-Ti files fractured within 4 mm from the tip which belongs to the pattern of ductile fracture.