Shaping ability of a pediatric motor-driven instrumentation system in primary molar root canal prototypes

Abstract Evaluate the shaping ability and preparation time using a pediatric motor-driven rotary instrumentation compared to other systems in resin prototypes of primary molars. Methods: Thirty specimens were scanned in micro-CT and divided into three groups according to the instrumentation type: pediatric motor-driven Sequence baby File (SBF); conventional motor-driven (Sequence Rotary File - SRF); manual K file. Instrumentation time was timed. After preparation, the specimens were scanned again. The pre- and post-instrumentation images were superimposed to measure the amount of root canal deviation and the resin remnant thickness. ANOVA followed by the Tukey test analyzed the comparisons between groups (p<0.05). Results: No statistically significant differences occurred in root canal deviation among groups (p>0.05). There were statistically significant differences in the comparison among root thirds (p<0.001) but without significant differences in the interaction group vs. root third (p>0.05). Both motor-driven instrumentations showed statistically greater weariness than manual instrumentation (p<0.001), without significant significant differences between SBF and SRF. Motor-driven instrumentation had a shorter working time than manual instrumentation (p<0.001). Conclusion: Pediatric motor-driven instrumentation demonstrated good outcomes in relation to root canal deviation and amount of remnant structure, with shorter instrumentation time. SBF can be a suitable alternative for endodontic instrumentation in primary molars.

Resumo Objetivo: Avaliar os resultados da instrumentação endodôntica e o tempo de preparo de lima odontopediátrica ativada por motor (Sequence Baby File- SBF) em canais de molares decíduos prototipados. Métodos: Trinta espécimes foram escaneados em micro-CT e divididos em três grupos de acordo com o tipo de instrumentação: mecanizada odontopediátrica (SBF); mecanizada convencional; lima K manual. O tempo de instrumentação foi cronometrado. Após o preparo, os espécimes foram escaneados novamente. As imagens pré e pós-instrumentação foram sobrepostas e a quantidade de desvio do canal radicular e a espessura de resina remanescente foram mensurados. Para as análises de comparações entre os grupos foram realizados teste ANOVA seguido do teste de Tukey (p<0,05). Resultados: Não ocorreram diferenças estatisticamente significativas entre os grupos no desvio do canal radicular (p>0,05). Houve diferenças estatisticamente significativas na comparação entre terços radiculares (p<0,001), mas sem diferenças significativas na interação grupo vs. terço radicular (p>0,05). A instrumentação mecanizada apresentou desgaste estatisticamente maior do que a instrumentação manual (p<0,001), sem diferenças estatísticas entre a SBF e a lima mecanizada convencional. A instrumentação mecanizada teve menor tempo de trabalho quando comparado a instrumentação manual (p<0,001). Conclusão: A instrumentação mecanizada odontopediátrica demonstrou bons resultados em relação ao desvio do canal radicular e quantidade de estrutura remanescente, com menor tempo de instrumentação. A SBF pode ser uma alternativa adequada para a instrumentação endodôntica em molares decíduos.

Apical extrusion of debris when using OneCurve, ProTaper Next and TruNatomy in curved canals.

BACKGROUND: The extrusion of apical debris is related to various factors, and may be affected by variations in technique or instrumentation system. Although the extrusion cannot be completely prevented, it is crucial to minimize the amount of extruded material. OBJECTIVES: The present study aimed to compare apical debris extrusion by the novel TruNatomy (TRN), OneCurve (OC) and ProTaper Next (PTN) instruments in curved root canals. MATERIAL AND METHODS: A total of 60 multi-rooted human mandibular molar teeth with moderate and severe curvature were selected and randomly divided into 3 groups. The root canals were prepared with the OC, TRN and PTN files. For collecting the debris extruded through the apical foramen, Eppendorf tubes were used. After the vaporizing period, the tubes were re-weighed, and the amount of the extruded debris was calculated by subtracting the initial weight from the final weight. Statistical analysis was performed with the Shapiro-Wilk and Kruskal-Wallis tests. The statistical significance level was set at p < 0.05. RESULTS: The least amount of debris was extruded with TRN and the greatest with PTN, but the difference between the groups was not significant (p = 0.257). CONCLUSIONS: All instrumentation systems were associated with debris extrusion. The tested file systems presented similar results in terms of apical debris extrusion in curved canals. The novel TRN system demonstrated promising results, comparable to OC and PTN.

Severity of Post-Operative Pain after Instrumentation of Root Canals by XP-Endo and SAF Full Sequences Compared to Manual Instrumentation: A Randomized Clinical Trial.

This investigation aimed to examine the post-operative pain experienced following single-visit root canal treatment using the XP-endo shaper sequence (XPS), full-sequence self-adjusting file (SAF), and manual K-files (HKF). A randomized equivalence parallel design, double-blinded clinical study was conducted on 120 patients with symptomatic irreversible pulpitis, with or without clinical signs of apical periodontitis. Only teeth with fully formed roots and no periapical lesions were incorporated in the study. Patients were apportioned to one of three groups (n = 40) randomly: Group 1-XPS, Group 2-SAF, and Group 3-HKF. Pre- and post-instrumentation pain was rated utilizing Visual Analog Scale (VAS) with a spectrum of 0-100 mm. The descriptive statistics and one-way ANOVA with 95% confidence intervals were used for statistical analysis. The mean VAS scores before instrumentation were consistent in all three groups. At 6, 24, 48, and 72 h, patients with root canals instrumented by SAF had the lowest post-instrumentation mean VAS score, followed by XPS. For all time intervals, the patients in the HKF group had the highest VAS score. The full-sequence SAF instrumentation resulted in less post-operative pain than the XP-endo plus protocol, while manual instrumentation with K-files resulted in the highest post-operative pain.

Tempo e resultados biomecânicos da instrumentação endodôntica rotatória comparada a manual em protótipos de molares decíduos: estudo in vitro / Time and biomechanical results of rotary endodontic instrumentation compared to manual in deciduous molar prototypes: in vitro study

Objetivou-se elaborar um e-book aos cirurgiões-dentistas sobre as opções de sistema de instrumentação endodôntica para dentes decíduos e comparar os resultados biomecânicos de diferentes sistemas e seu tempo de preparo em protótipos de dentes decíduos por meio de uma análise em micro-CT. Para isso, foram realizados dois estudos. No primeiro, realizou-se uma busca bibliográfica em seis bases de dados por estudos laboratoriais e clínicos sobre protocolos de pulpectomia utilizando pelo menos uma técnica de instrumentação. Dados a respeito das características, cinemática, benefícios e orientações à cerca da utilização de acordo com as instruções dos fabricantes foram extraídos para elaboração do conteúdo teórico e diagramação do layout do e-book, confeccionado no programa Canva. Após finalizado, o mesmo foi avaliado por três pós-graduandos da Disciplina de Odontopediatria da FOUFRJ e as sugestões foram incorporadas. Elaborou-se o material intitulado ''Guia ilustrado de instrumentação endodôntica para dentes decíduos'' contendo 43 páginas, abordando 13 sistemas de instrumentação, com sequências ilustradas de protocolos para utilização. Para o segundo estudo foram utilizados 60 protótipos padronizados de segundos molares decíduos inferiores confeccionados em polímero transparente para avaliar os resultados biomecânicos da instrumentação com diferentes sistemas de limas. Foram utilizados os sistemas manual k-file e mecanizados ProTaper Nextâ (PTN), XP- Endoâ Shaper (XPS), XP- Endoâ Finisher (XPF), XP­Clean (XPC) e Sequence Baby file (SBF) (n= 10/cada). A instrumentação foi realizada por um único operador treinado e o tempo de utilização de cada sistema foi cronometrado. Realizouse a irrigação com um total de 16mL de soro fisiológico à 0,9% para cada canal instrumentado, associada a aspiração simultânea. Os protótipos foram escaneados antes e após da instrumentação através do micro-CT. A reconstrução foi padronizada os conjuntos de imagens iniciais e instrumentados foram registrados entre si. Alterações no volume do canal radicular, área não instrumentada, debris acumulados, volume de dentina removido e transporte do canal foram quantificados. Os dados foram tabulados no programa JAMOVI versão 1.6 e analisados através do teste Shapiro-Wilk para verificar a distribuição dos dados. Para distribuição normal foram realizados testes paramétricos e para aqueles que não seguiram a normalidade, testes não paramétricos foram utilizados, todos com um nível de significância de 5% (p<0,05). A instrumentação com sistemas mecanizados resultou em menos tempo de instrumentação (p< 0,001) do que com a k-file. A porcentagem de áreas não instrumentadas foi semelhante para todos os sistemas. O acúmulo de debris foi maior para K-file e XPS ao longo de todo o canal (p<0,05). Todos os grupos apresentaram aumento do volume do canal radicular após a instrumentação (p= 0,003) com valores mais elevados na lima K-file (p<0,05). A análise 3D revelou maior transporte da lima K-file. SBF e K-file apresentaram, respectivamente, o menor (0,01 ± 0,01 e 0,03 ± 0,04) e o maior (0,04 ± 0,05 e 0,32 ± 0,94) valor de transporte do canal nos protótipos. Diante das metodologias utilizadas, conclui-se que um material relevante e prático ficará disponível nas plataformas digitais da Disciplina de Odontopediatria da UFRJ, para livre acesso e ampla divulgação aos cirurgiões-dentistas. Além disso, com relação aos resultados de instrumentação mecânica, o SBF e o XPC resultaram em uma abordagem mais conservadora. A instrumentação mecânica pode levar à algum grau de transporte do canal e deixar partes das paredes do canal infectadas sem preparo mecânico. (AU)

The objective was to elaborate an e-book to dentists about the options of endodontic instrumentation system for primary teeth and to compare the biomechanical outcomes of the different systems and their instrumentation time in prototypes of primary teeth through micro-CT analysis. To this end, two studies were carried out. In developing the first, a bibliographic search was carried out in six databases. Laboratory and clinical studies with a pulpectomy protocol using at least one instrumentation technique were included. Data about features, kinematics, benefits, and guidelines on use according to the manufacturer's instructions were extracted to prepare the theoretical content and layout diagramming of the e-book using Canva software. Afterwards, it was evaluated by 3 postgraduate students of the Pediatric Dentistry Discipline-FOUFRJ and the suggestions for changes were incorporated. The product entitled 'Guia ilustrado de instrumentação endodôntica para dentes decíduos' contains 43 pages covering 13 instrumentation systems and illustrated sequence of protocols use for each. The second consists of 60 standardized prototype teeth of mandibular second primary molars made with transparent polymer to evaluate the outcomes of biomechanical instrumentation of different systems. Manual k-file, ProTaper Nextâ (PTN), XP-Endoâ Shaper (XPS), XP-Endoâ Finisher (XPF), XP ­ Clean (XPC) and Sequence Baby file (SBF) (n= 10/each) were used. The specimen instrumentation was performed by a single trained and the time spend was recorded. Irrigation was performed with a total of 16mL of 0.9% saline solution for each instrumented canal and simultaneous aspiration. The prototypes were scanned before and after the instrumentation using micro-CT. In addition, the reconstruction was standardized and initial and instrumented image sets were registered with each other. Next, changes in root canal volume, noninstrumented areas, accumulated debris, removed dentin volume and canal transportation were quantified. Data were tabulated in the JAMOVI program version 1.6 and analyzed using the Shapiro-Wilk test to verify the data distribution. For normal distribution, parametric tests were performed and that did not follow normality, nonnormal tests were used, all with a significance level of 5% (p<0.05). Instrumentation with rotary files resulted in less time-consuming (p <0.001) than manual k-file. The percentage of non-instrument areas were similar for all systems. Accumulated debris was higher for K-file and XPS along the entire canal. All groups showed an increase in root canal volume after instrumentation (p= 0.003) with higher values in K-file (p <0.05). 3D analysis revealed greater transportation in K-file. SBF and K-file showed, respectively, the lowest (0.01± 0.01 and 0.03 ± 0.04) and highest (0.04 ± 0.05 and 0.32 ± 0.94) canal transportation value in the prototypes. Given the methodology applied, it was concluded that: the didactic material will be available on the digital platforms of Pediatric Dentistry at UFRJ for free access and widespread. From the overall mechanical instrumentation outcomes, the SBF and XPC resulted in a more conservative approach. Mechanical instrumentation may lead transportation and leave preparation. (AU)

Etiology and Prevention of an Endodontic Iatrogenic Event: Instrument Fracture.

Although benefiting from an unprecedented technological evolution, contemporary endodontics is still characterized by the recurrence of retreatments, due to the need to solve quite frequent incidents, accidents, or even failures of primary endodontic treatment. This survey aims to assess both the etiology and the prevention methods of one of the most troublesome endodontic iatrogenies: instrument separation during root canal shaping. The multifactorial nature of this occurrence entails identifying and taking into account all the causal and contributing factors. Their significant number and the possible involvement of any of them, starting with the complexity and variability of the root canals and ending with the technical specifications concerning the nickel-titanium rotary instrumentation system being used, highlight the necessity to develop valid guidelines to avert the occurring of such an upsetting situation.

Relationship between Canal Enlargement and Fracture Load of Root Dentin Sections.

OBJECTIVE: To investigate the effect of endodontic instrumentation on fracture susceptibility of root dentin using experiments and stress analysis. METHODS: Root canals of lower premolars were enlarged with different tapers. After, teeth were cut into 2-mm sections. A metal rod of the same taper was pushed through the center of the sections using a universal test system to fracture them. The fracture load was determined from the peak load on the load-displacement curve. To determine fracture-causing stress, an axisymmetric FE model was created. An analytical solution was developed to understand the relationship between fracture load, geometrical and material parameters. RESULTS: For the same taper, increased root canal diameter did not lead to reduced fracture load. Both analytical and FE solutions showed positive linear relationship between fracture load and enlarged root canal diameter. The hoop stress was maximum at inner surface of enlarged root canal and reduced with increasing radial distance from the center. Bending of sections introduced further nonuniform stresses along the depth. Predictions for the fracture load based on the maximum hoop stress were closest to experimental values; however, account must be taken of the variation in fracture stress of dentin along the root length. Significance Our results rejected the hypothesis that fracture load of root dentin sections reduced with endodontic instrumentation size. However, the stress distributions in whole endodontically treated teeth are more complicated. Thus, caution is necessary when using thin root sections to investigate the effect of endodontic instruments on vertical root fracture.

A microcomputed tomography evaluation of the shaping ability of three thermally-treated nickel-titanium rotary file systems in curved canals.

OBJECTIVE: To evaluate the shaping ability of three thermally-treated rotary nickel-titanium (NiTi) systems including ProTaper Next (PTN), HyFlex™ CM (HFCM) and HyFlex™ EDM (HFEDM) during root canal preparation in simulated root canals. METHODS: A total of 45 simulated root canals were divided into three groups ( n = 15) and prepared with PTN, HFCM or HFEDM files up to size 25. Microcomputed tomography (microCT) was used to scan the specimens before and after instrumentation. Volume and diameter changes, transportations and centring ratios at 11 levels of the simulated root canals were measured and compared. RESULTS: HFEDM caused significantly greater volume increases than HFCM and PTN in the entire root canal and in the apical and middle thirds. HFCM removed the least amount of resin in the coronal third compared with HFEDM and PTN. Overall, HFCM caused significantly less transportation in the apical 2 mm and was better centred than PTN in the apical 3 mm. CONCLUSION: Under the conditions of this study, all systems prepared curved canals without significant shaping errors and instrument fracture. PTN and HFCM cut less resin than HFEDM. HFCM stayed centred apically and cut the least material coronally.

Reciprocating instrumentation in a maxillary primary central incisor: A protocol tested in a 3D printed prototype.

BACKGROUND: Efficient endodontic instrumentation of primary teeth is a challenge for paediatric dentists. AIM: To evaluate biomechanical outcomes of endodontic instrumentation with a reciprocating system in a polymer-prototyped primary maxillary central incisor. DESIGN: The specimen was systematically instrumented and micro-CT scanned before and after each file. The amount of debris, percentage of non-instrumented areas, removed dentin volume, and lower dentin thickness at specific points along the root canal were analyzed. RESULTS: A 10% increase in removed dentin volume was observed when R40 was compared to R25 (14.5% vs 4.2%). When comparing R50 with R40, this increase was only 3.4% (17.9% vs 14.5%). In the root cervical third, there was substantial reduction in dentin thickness with R50 (48.8%), followed by R40 (39.5%) and R25 (18.6%). There was no difference between R25 and R40 in the removal of dentin at the apical third (15.8%), while R50 resulted in 39.8% reduction in dentin thickness. Percentage of non-instrumented areas were the same for all files. Accumulated debris with R40 and R50 was the same (0.19 mm³) while for R25 was 0.11 mm³. CONCLUSIONS: The Reciproc® system was effective for instrumentation of a prototyped primary maxillary central incisor. The most suitable file for apical preparation was R40.

Apical extrusion of debris in four different endodontic instrumentation systems: A meta-analysis.

BACKGROUND: All endodontic instrumentation systems tested so far, promote apical extrusion of debris, which is one of the main causes of postoperative pain, flare ups, and delayed healing. OBJECTIVES: Of this meta-analysis was to collect and analyze in vitro studies quantifying apically extruded debris while using Hand ProTaper (manual), ProTaper Universal (rotary), Wave One (reciprocating), and self-adjusting file (SAF; vibratory) endodontic instrumentation systems and to determine methods which produced lesser extrusion of debris apically. METHODOLOGY: An extensive electronic database search was done in PubMed, Scopus, Cochrane, LILACS, and Google Scholar from inception until February 2016 using the key terms "Apical Debris Extrusion, extruded material, and manual/rotary/reciprocating/SAF systems." A systematic search strategy was followed to extract 12 potential articles from a total of 1352 articles. The overall effect size was calculated from the raw mean difference of weight of apically extruded debris. RESULTS: Statistically significant difference was seen in the following comparisons: SAF < Wave One, SAF < Rotary ProTaper. CONCLUSIONS: Apical extrusion of debris was invariably present in all the instrumentation systems analyzed. SAF system seemed to be periapical tissue friendly as it caused reduced apical extrusion compared to Rotary ProTaper and Wave One.

The Influence of a New Clinical Motion for Endodontic Instruments on the Incidence of Postoperative Pain.

OBJECTIVES: Previous studies showed that motor motions play an important role in determining apical extrusion of debris. Therefore a new clinical motion (MIMERACI) has been proposed. The basic idea is to progress slowly (1mm advancement), and after each 1mm, to remove the instrument from the canal, clean flutes and irrigate. The aim of the study was to prove whether the clinical use of MIMERACI technique would influence or not postoperative pain. MATERIALS AND METHODS: 100 teeth requesting endodontic treatment were selected for the study and divided into two similar groups based on anatomy, pre-operative symptoms and vitality, presence or absence of periapical lesion. All teeth were shaped, cleaned and obturated by the same operator, using the same NiTi instruments. The only difference between the two groups was the instrumentation technique: tradional (group A) vs MIMERACI (group B). Assessment of postoperative pain was performed 3 days after treatment. Presence, absence and degree of pain were recorded with a visual analogue scale (VAS), validated in previous studies. Collected data statistically analyzed using one-way ANOVA post hoc Tukey test. RESULTS: For VAS pain scores MIMERACI technique showed significantly better results than group A (p=0,031). Overall, both incidence and intensity of symptoms were significantly lower. Flare ups occurred in 3 patients, but none treated with the MIMERACI Technique. CONCLUSIONS: Since extruded debris can elicit more postoperative pain, results obtained by using MIMERACI technique are probably due to many factors: better mechanical removal and less production of debris and more efficient irrigation during instrumentation.

Longitud de las piezas dentales en Costa Rica

El profesional en Endodoncia se plantea el dilema de hasta qué punto deben penetrar los instrumentos dentro del conducto. Por esta razón, la longitud real de las diferentes piezas dentales en distintas etnias y zonas geográficas de un mismo país es un dato importante y característico. Este estudio se realizó por medio de un análisis tomográfico en piezas extraídas. Se tomó una muestra representativa de las siete provincias de Costa Rica, utilizando 1470 raíces de 980 piezas dentales, 70 piezas superiores e inferiores, mostrando 210 raíces en su totalidad por provincia. Se logró determinar las longitudes reales de las diferentes piezas dentales de los costarricenses. De acuerdo con la metodología utilizada, la muestra fue probabilística de tipo estratificado, con el fin de asegurar una representación de cada una de las provincias del país; se recolectaron piezas dentales en clínicas dentales privadas y públicas. Los resultados reflejan piezas dentales con medidas que se asemejan a otros estudios realizados en otras partes del mundo.

The great dilemma for the practitioner in endodontics is how far to penetrate with the instruments within the duct. For this reason, the real longitude of the different teeth in various ethnias and geographic zones of the same country is an important and characteristic data. This research was done through a tomographic analysis of the extracted teeth. A representative sample of the seven provinces of Costa Rica was taken, using 1470 roots of 980 teeth, 70 superior teeth and inferior, giving 210 roots in total per province. It was possible to determine the real longitudes of the different teeth of the costaricans. According to the methodology used, the sample was probable of the stratified type with the objective goal of assuring a representation of each one of the provinces of the country; the dental pieces were collected through private and public dental clinics. The results reflect teeth with similar measurements to other studies done in other parts of the world.

Effect of the Nd:YAG laser on sealer penetration into root canal surfaces: a confocal microscope analysis.

OBJECTIVES: The objective of this in vitro study was to evaluate the use of the Neodymium:Yttrium-Aluminium-Garnet (Nd:YAG) laser as part of the root canal treatment on the penetration of sealer into dentinal tubules. METHODS: Eighty extracted lower premolars were randomly assigned to two groups (n=40 each): Control group (CG), subjected to a conventional protocol of endodontic instrumentation and obturation; and Laser group (LG), in which Nd:YAG laser irradiations were combined with conventional preparation and obturation. Endodonted samples were sectioned at 3 and 5 mm from the apex and observed under a confocal scanning microscope (CLSM). The penetration depth into the dentinal tubules and the extension of the intracanal perimeter infiltrated by sealer were measured. The Student-Newman-Keuls test was run for between-group comparisons (α=.05). RESULTS: The depth of sealer penetration into dentinal tubules did not differ among groups. LG samples showed the significantly highest percentage of penetrated perimeter at 3 mm from the root apex. Within each group, the greatest depth of penetration (P=.0001), and the major percentage of penetrated perimeter (P<.001), were recorded at 5 mm. CONCLUSIONS: The application of the Nd:YAG laser after instrumentation did not improve the depth of sealer penetration into the dentinal tubules. The laser enlarged the total penetrable perimeter near the apex. CLINICAL SIGNIFICANCE: The Nd:YAG laser may be an appropriate complement in root canal treatment, as it enhances the sealer adaptation to the dentinal walls in the proximity of the apex.

The effect of occlusal reduction on pain after endodontic instrumentation / 实用口腔医学杂志

0.01). Conclusion: Occlusal reduction might diminish the rate of postoperative pain following endodontic instrumentation.