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Post Space Debridement in Oval-shaped Canals: The Use of a New Ultrasonic Tip with Oval Section
Abstract
This study evaluates the effect on post space debridement in oval-shaped canals of an experimental ultrasonic tip with oval section (Satelec) compared with a circular ultrasonic tip (KaVo). Thirty teeth with an oval-shaped canal were endodontically treated and obturated and then randomly divided into 3 groups (n = 10) according to the procedure used for post space debridement: Satelec tip, Largo #2 drill + KaVo file, and Largo #2 drill + water. Debris and dentin tubules were evaluated by assigning scores to scanning electron microscope post spaces images; lower scores corresponded to fewer debris and higher number of open tubules. The Satelec group showed significantly lower debris and open tubules scores than KaVo group (p < .05) and control group (p < .05), which differed significantly between each other (p < .05). Also the debris and open tubules scores in different post space regions differed significantly among the experimental groups (p < .001). The oval ultrasonic tip resulted in a better post space debridement than a circular ultrasonic tip in oval-shaped canals.
... Los resultados obtenidos en este estudio muestran diferencias en la resistencia a la tracción entre los dos grupos, presentando los mayores valores el grupo desobturado ultrasónicamente y siendo estadísticamente significativas entre ambos grupos en el tercio cervical. La preparación rotatoria del espacio protésico utiliza fresas de sección transversal circular, actuando solamente en las paredes del conducto donde se posicionará el poste (Coniglio et al., 2008). El uso de estas fresas en conductos ovales, deja paredes intactas con materiales de obturación endodóntico y debris residual (Keles et al, 2014;Rivera-Peña et al., 2019), lo que se traduce en una menor superficie disponible para la cementación adhesiva de postes de fibroresina aumentando el riesgo de desalojo (Maroulakos et al., 2018). ...
... Por otro lado, los resultados obtenidos al utilizar el ultrasonido como complemento a la preparación del espacio protésico rotatoria, demostraron la efectividad de este método al permitir eliminar el material de obturación endodóntico en paredes no tocadas por las fresas (Coniglio et al, 2008; traduciéndose en mayores valores de resistencia (Uzun et al., 2016), los cuales son estadísticamente significativos respecto al grupo desobturado rotatoriamente, incluso superando los valores del grupo control en el tercio cervical y medio. Estos resultados coinciden con los encontrados por Coniglio et al. (2008) quienes también aseguran que el ultrasonido es capaz de mantener de mejor forma la anatomía original del conducto sin generar grandes deformaciones como lo que ocurre con el instrumental rotatorio (Rivera-Peña et al.). ...
... Por otro lado, los resultados obtenidos al utilizar el ultrasonido como complemento a la preparación del espacio protésico rotatoria, demostraron la efectividad de este método al permitir eliminar el material de obturación endodóntico en paredes no tocadas por las fresas (Coniglio et al, 2008; traduciéndose en mayores valores de resistencia (Uzun et al., 2016), los cuales son estadísticamente significativos respecto al grupo desobturado rotatoriamente, incluso superando los valores del grupo control en el tercio cervical y medio. Estos resultados coinciden con los encontrados por Coniglio et al. (2008) quienes también aseguran que el ultrasonido es capaz de mantener de mejor forma la anatomía original del conducto sin generar grandes deformaciones como lo que ocurre con el instrumental rotatorio (Rivera-Peña et al.). ...
Untouched canal walls with residual filling materials can increase the probability of adhesive failure of fiber posts. The drills used for desobturation and conformation of the prosthetic space, has a circular cross section, which does not allow a proper preparation and cleaning of oval-shaped canal walls. The objective of the study was to evaluate the ultrasonic cleaning of the prosthetic space and how this influences the adhesive strength of fiber posts in oval-shaped canals. Thirty (30) oval-shaped canal premolars were randomly divided into 3 groups (n = 10): Group A: rotary desobturation with ultrasonic complement, group B: rotary desobturation without ultrasonic complement and group C: control group. Fiberglass posts were cemented; after 7 days, one-millimeter slices were performed, one of the cervical and another from the middle third of the root. The slices were analyzed under an optical microscope to evaluate remaining gutta percha and effective adhesion area. Samples were subjected to a push-out test to evaluate bond strength of the fiber resin posts. Finally, samples were evaluated microscopically to analyze the type of failure. The results were analyzed using ANOVA, Bonferroni, KruskalWallis and Mann Whitney test (p < 0.05), recording statistically significant differences in bond strength, remaining gutta-percha area and clean walls for adhesion; In addition, to a direct relationship between remaining gutta percha and lower adhesive strength, the ultrasonic preparation of the prosthetic space increases bond strength of fiber posts in oval canals.
... 1,2,3,4,5 The presence of these anatomical features has been associated with complications during instrumentation with hand and engine-driven instruments, hindering the cleanliness of the root canal system. 6,7,8,9,10,11,12,13 Nickel-titanium (NiTi) instrumentation tends to maintain a self-centered position during rotation, creating a circular bulge and producing a smear layer in the prepared portions of Declaration of Interests: The authors certify that they have no commercial or associative interest that represents a conflict of interest in connection with the manuscript. the root canal walls, whereas pulp remnants and infected dentin remain in the areas untouched by endodontic files. ...
... the root canal walls, whereas pulp remnants and infected dentin remain in the areas untouched by endodontic files. 11 Microcomputed tomography (µCT) studies have revealed that more than half of the root canal walls (ranging from 59.6% to 79.9%) remain unprepared in oval-shaped canals, irrespective of the instrumentation technique. 14 Microcomputed tomography imaging technology allows detailed visualization of the morphological characteristics of teeth. ...
... 33 The shaping and cleaning of ovalshaped canals represent a challenge because these root canals tend to have a greater buccolingual dimension and endodontic instruments tend to remain at the center of the canal. 11,19,34 This leads to non-instrumented areas that could influence the outcome of the treatment. 11,13,19 However, it has been observed that the efficacy of instrumentation is closely associated with the canal anatomy and pathosis than with the use of any mechanical devices. ...
To evaluate the influence of novel ultrasonic tips as an auxiliary method for the rotary preparation of flattened/oval-shaped canals. Forty-five mandibular incisors were selected and divided into one of three experimental groups (n = 15): Group PFCP – ProDesign Logic 25/.05 + Flatsonic + Clearsonic + Prodesign Logic 40/.01; Group FCP – Flatsonic + Clearsonic + ProDesign Logic 40/.01; and Group PP – Prodesign Logic 25/.05 + Prodesign Logic 40/.05. The teeth were scanned preoperatively and postoperatively using microcomputed tomography. The percentage values for increase in volume, non-instrumented surface area, dentin removal, degree of canal transportation, and centering ratio between the experimental groups were examined. Data were analyzed using the non-parametric Kruskal-Wallis and Dunn’s tests (p < 0.05). Group PFCP showed the greatest volume increase in the total portion of the root canal and the lowest percentage of non-instrumented surface area. Regarding the degree of transportation in the buccolingual direction, statistically significant differences between groups PFCP and PP were observed at the coronal third of the canal. In the mesiodistal direction, no statistically significant differences were observed at the coronal, middle, and apical thirds. As for the centering ratio, statistically significant differences were found in the buccolingual direction. In the mesiodistal direction, no statistically significant differences were observed at the coronal, middle, and apical thirds. The use of novel ultrasonic tips combined with rotary instruments in group PFCP provided a significant increase in volume and reduced the percentage of non-instrumented areas during the preparation of flattened/oval-shaped canals.
... Post boşluğu hazırlamada kullanılan geleneksel driller de bu kurala uyarak, oval kanallarda temas etmedikleri dentin duvarlarında rezidüel kanal dolgu materyali kalmasına, debrisin birikmesine ve "smear" tabakasının meydana gelmesine neden olmaktadır. 15 Bununla beraber, drill kullanımı sağ lam dentin dokusunun kaybına ve kök kırığı riskinin artmasına neden olmaktadır. 3 Oval kök kanallarının restorasyonunda ve sonrasında meydana gelen problemlerin önlenmesi için farklı post sistemleri dizayn edilmiştir. ...
... Ellipson oval ultrasonik uçların kanal anatomisini koruyarak daha koruyucu preparasyonlar yaptığı ve geleneksel drill ile preparasyona göre daha iyi debridman sağladığı belirtilmiştir. 15 Bu çalışmanın amacı, çekilmiş mandibüler premolar dişlerin oval kök kanallarına self-adeziv rezin siman ile yapıştırılmış prefabrik oval fiber ve yuvarlak fiber postların "push-out" bağlanma dayanımlarını karşılaştırmak ve değerlendirmektir. ...
... 9 Ancak, Ellipson oval ultrasonik uç kullanımının post boşluğunun debridmanını artırdığı ve "smear" tabakasını kaldırmada etkili olduğu da rapor edilmiştir. 15 Bu çalışmada Ellipson oval ultrasonik uç ile hazırlanan post boşluklarına oval fiber post uygulanması, geleneksel drilllerle hazırlanmış post boşluklarına uygulanan yuvarlak fiber postlara göre "push-out" bağlantı dayanımını artırmıştır. "Smear" tabakasının uzaklaştırılmış olması ve etkili debridman daha yüksek bağlanma dayanımı değerlerinin elde edilmesinde etkili olabilir. ...
Objective: To compare and evaluate push-out bond strength of prefabricated oval and circular fiber posts luted with self-adhesive resin cement in oval root canals in vitro. Material and Methods: Fifty extracted mandibular premolar teeth were used. Ovality of root canals were confirmed by radiographic examination. Teeth were decoronized. Mean length of roots were 13 mm. 48 h after completion of root canal treatments teeth were randomly divided into two groups: oval fiber post and circular fiber post groups. 8 mm of post spaces were prepared leaving 5 mm root canal filling material apically. For post space preparation, Ellipson oval ultrasonic tip was used in oval fiber post group whereas; conventional drill was used in circular fiber post group. All posts were luted using RelyX Unicem self-adhesive luting cement. Data were statistically analyzed using t-test. Results: Push-out bond strength of oval fiber and circular fiber posts showed statistically significant difference (p<0.05). Conclusion: Oval fiber posts showed higher push-out bond strength in oval canals than circular fiber posts did. In coronal region, oval fiber posts showed higher push-out bond strength values than circular fiber posts. In apical region post type did not effect bond strength.
Keywords: Endodontics; dental restoration, permanen
... Recently, posts with oval cross sections have been introduced in an effort to achieve better adaptation to the post space in oval canals. Drills are usually employed for post space preparation in oval canals, but this procedure alters canal anatomy and sacrifices dentine (Coniglio et al. 2008). The primary goal is to achieve the best possible adaption of the fibre post to the canal walls, thereby minimizing the thickness of the cement layer (Coniglio et al. 2009). ...
... Many root canals are not circular (Peters 2004). The difficulties of completely eliminating gutta-percha remnants , endodontic sealer and the smear layer from post space walls are enhanced in oval canals (Coniglio et al. 2008), affecting the adaptation and bond strength of fibre posts. The results of this laboratory study led to the partial rejection of the null hypothesis, as only bond strength was related significantly to both fibre post shape and post space preparation technique. ...
... As previously mentioned, this problem is enhanced in root canals with irregular morphology, where the use of a dedicated drill or ultrasonic tip is not significantly effective in dentinal wall debridement . In oval canals, it has been showed (Coniglio et al. 2008) that round-shaped instruments are not able to perform effective post space debridement, leaving debris on dentinal walls particularly in buccal and lingual extensions or recesses. Other clinical factors may be related to this result, such as the distance from the curing light (GoracciTable 1 Mean proportion of post space occupied by the post [ Post adhesion in oval-shaped canals Scotti et al. et al. 2008 ), the less dense dentinal tubule configuration in the apical region of the root canal system (Shemesh et al. 2006), apical sclerosis (Paque et al. 2006), the cavity configuration factor (Tay et al. 2005), and/or restrictions in the flow of cement to this part of the root canal (de Dur^ ao Mauricio et al. 2007). ...
To evaluate ex vivo the bond strength and adaptation of fibre posts with oval and circular cross sections luted in oval canals with post spaces prepared using dedicated drills or ultrasonic tips.
Forty extracted premolars with oval canals were root filled, then randomly divided into four groups according to the post space preparation device and the shape of the luted fibre post: dedicated drill + round post, dedicated drill + oval post, ultrasonic tip + round post and ultrasonic tip + oval post. Posts were cemented with a self-adhesive cement (RelyX Unicem 2; 3M ESPE). Samples were sectioned in 1-mm-thick slices and observed under a microscope, and the area occupied by the post within the post space area was calculated. Bond strength was then measured using a push-out test, and the failure modes were evaluated with a stereomicroscope at 40× magnification. Fibre post adaptation and push-out test results were evaluated by analysis of variance (P < 0.05).
Fibre posts, both round and oval, were better adapted to the apical region of the post space (P = 0.001). In oval canals, the bond strength was significantly higher in coronal regions, when the post space was prepared with a dedicated drill and an oval post was luted (P < 0.0001). Adhesive failures between cement and post were the most frequent type of failure in all groups.
Circular and oval posts achieved similar adaptation to oval canals, but the use of ultrasonic tips and round posts resulted in reduced bond strength values.
... In oval-shaped canals, 10 circular posts do not present a good post fitting due to the discrepancy between the post's circular shape and canal's anatomy. Thus, to fit the post, preformed drills used for post-space preparation alter the anatomy of oval canals, 11 sacrificing dentin tissue. To reduce this alteration, a more conservative drill a suitable for all canals 12 and a medium grit ultrasonic oval tip (Ellipson tip b ) designed for oval-shaped canals were investigated and proposed. ...
... To reduce this alteration, a more conservative drill a suitable for all canals 12 and a medium grit ultrasonic oval tip (Ellipson tip b ) designed for oval-shaped canals were investigated and proposed. 11,12 The latter respected the canal shape but appeared quite aggressive on dentin walls; therefore a fine grit tip was advocated. 11 Recently, preformed posts with oval section (Ellipson posts b ) have been proposed for oval-shaped post-spaces, aiming to achieve a better fiber post adaptation to the post space walls, as they reproduce the oval form of this type of canals. ...
... 11,12 The latter respected the canal shape but appeared quite aggressive on dentin walls; therefore a fine grit tip was advocated. 11 Recently, preformed posts with oval section (Ellipson posts b ) have been proposed for oval-shaped post-spaces, aiming to achieve a better fiber post adaptation to the post space walls, as they reproduce the oval form of this type of canals. ...
To evaluate the cement thickness around oval and circular posts luted in oval post spaces prepared with different drills/tips.
Extracted premolars were endodontically treated and obturated, then randomly divided into three groups (n = 5) according to the tips/drills used for post-space preparation and to the type of fiber post luted: medium grit oval tip + oval posts, fine grit oval tip + oval posts, Mtwo Post File drill + circular posts. The specimens were sectioned in horizontal slices; one slice per canal third was chosen for each post-space, resulting in three slices for each specimen. The distances between the canal wall and the post perimeter were measured on SEM images of each slice.
The fine grit tip + oval post group obtained statistically significant lower cement thicknesses than the other groups (P < 0.05), in particular in the apical third. The MtwoPF + circular post group showed the highest cement thickness, comparable to that of the medium tip + oval post group. A good post fitting in oval-shaped canals can be obtained using a fine grit oval tip combined with oval posts.
... The difficulty to completely remove root canal filling will result in material remnants on root dentin walls, and the presence of such residues impairs the adhesion of glass fiber post. Thus, several methods have been tested aiming to completely remove filling material, for adequate luting of intraradicular post (Coniglio et al., 2008a(Coniglio et al., , 2008bZhang et al., 2008;Bitter et al., 2012). ...
... Some previous studies evaluated the cleaning of post space using different irrigants and materials, by optical and scanning electronic microscope (SEM) analyses (Coniglio et al., 2008a(Coniglio et al., , 2008bBitter et al.;Serafino et al., 2004Serafino et al., , 2006. However, those methods are qualitative, while energy dispersive spectroscopy (EDS) analysis of root dentin walls allows quantifying and identifying the chemical remaining components, and differentiating constituents of filling material and tooth. ...
This study evaluated the cleanliness of post space after different irrigation protocols, associated or not to the use of ultrasound. Thirty-six single-rooted bovine roots were instrumented with rotary system, irrigated with 1 % hypochlorite and filled with Ah Plus sealer and gutta-percha cones. After seven days in stove at 37 °C, two-thirds of canal filling was removed by drilling and the post space preparation was irrigated with 2.5 % NaOCl (group NaOCl); 0.2 % chlorhexidine (group CLX); distilled water (group Water); 2.5 % NaOCl + ultrasound (group NaOCl-US); 0.2 % chlorhexidine + US (Group CLX-US); or water + US (Group Water-US). Roots were cleaved in mesiodistal direction, prepared for scanning electron microscope (SEM) to evaluate the smear layer and debris presence and for energy dispersive spectroscopy (EDS) analyses, to evaluate chemical components of dentin after treatment. The data were subjected to statistical analysis (two-way Anova and Tukey's test 5 %). EDS analysis showed the presence of chemical components of filling material in the samples from all groups. SEM images showed large amount of obliterated dentinal tubules. The use of ultrasound influenced the removal of some components of filling material (p
... This procedure also decreases root strength (Schwartz 2006). Incomplete canal wall instrumentation and residual debris may also occur during the post space preparation (Coniglio et al. 2008). Recently, an experimental ultrasonic tip (Ellipson tip; Satelec, Acteon group, Merignac, France) with an oval shape was developed for post space preparation in oval canals that does not alter their configuration. ...
... Recently, an experimental ultrasonic tip (Ellipson tip; Satelec, Acteon group, Merignac, France) with an oval shape was developed for post space preparation in oval canals that does not alter their configuration. A previous study reported that oval ultrasonic tips achieved significantly superior post space dentinal wall debridement than did circular drills (Coniglio et al. 2008). ...
Aim:
To evaluate the percentage volume of voids within cement layers, to determine the push-out bond strength of circular and oval fibre posts luted with different commercial resin cements in oval cross-sectional root canals, and to correlate push-out bond strength values and volume of voids of circular and oval fibre posts.
Methodology:
Seventy-two mandibular premolars with oval-shaped root canals were selected. The specimens were divided into two main groups according to the post type (oval and circular). Groups were further divided into three subgroups (n = 24) according to resin cement type: Maxcem Elite, Rely-X Unicem, and Duo-Link. The volumes of voids within the cements were analysed by micro-computed tomography (micro-CT). The bond strength was then measured using a push-out test with an Instron universal testing machine. The failure modes were evaluated. Statistical analyses were performed using a three-way ANOVA, Tukey's post-hoc, Pearson's correlation and chi-square test (P=0.05).
Results:
The push-out bond strength values were significantly affected by root canal region, post type, and cement type (P<.001). Root canal region, post type, and cement type also significantly affected void volume (P<.001). There was a significant interaction between post type and cement type (P<.001). The most frequent failure type was adhesive failure in all the groups. There was no significant correlation between the push-out bond strength and void volume (P>.05).
Conclusions:
Void volume did not affect push-out bond strength of oval and circular post luted in oval canals. This article is protected by copyright. All rights reserved.
... Some studies have suggested that EDTA is effective in removing the smear layer both from the tubules and from the dentinal surface along the entire post-space [12,[19][20][21], but in deeper areas of post-space, it is more difficult to obtain a clean dentinal surface. Some studies reported that the use of EDTA combined with sodium hypochlorite [22,23] has been shown to cleanse the canal walls of the post-space, but NaOCl causes the release of oxygen, which can inhibit the polymerization of resinous materials [24,25]; therefore, the acid etching of dentine is still an essential step for obtaining clean canal walls and a greater adhesion force of the post-bond strength, which can be further obtained with the use of ultrasonic tools during the cleansing of the post-space, as shown in this study, and this appears to produce a better dentine substrate for adhesive post cementation. ...
Citation: Marchese, M.; Denise, P.I.K.; Ferrari Cagidiaco, E.; Iandolo, A.; Grandini, S.; Ferrari, M. Endodontic Irrigants and Their Activation Efficacy on Cleansing Post-Space Root Canal Walls. Prosthesis 2021, 3, 406-414.
... This could be due to less visibility in deeper areas of the post space resulting in a less predictable post space cleaning and therefore higher amounts of rough debris that occlude dentin tubules which are not available for adhesion. [24,25] Distribution and density of dentinal tubules, the difference in sclerosis between the middle portion and coronal third also may play a role. [26] The cavity configuration factor of the post space, degree of conversion of dual-cure resin at the coronal and middle region also has a role to play. ...
... 8 Several lines of evidence implicate TNF-α in the perpetuation of chemotaxis in inflammatory cells and fibroblasts. 9,10,11 More importantly, Graves 12 provided evidence of the involvement of TNF-α in periodontitis. Our previous experiments showed that 50 ng/ml TNF-α stimulation increased hDPSC migration in vitro through integrin α-6 subunit upregulation. ...
We recently demonstrated that a co-culture system of human umbilical vein endothelial cells (HUVECs) and human dental pulp stem cells (hDPSCs) could enhance angiogenesis ability in vitro. However, whether tumor necrosis factor α (TNF-α) could promote blood vessel formation during pulp regeneration remained unknown. The aim of this study was to investigate the effects of TNF-α on the formation of endothelial tubules and vascular networks in a co-culture system of hDPSCs and HUVECs. hDPSCs were co-cultured with HUVECs at a ratio of 1:5. The Matrigel assay was performed to detect the total tubule branching lengths and numbers of branches, and the Cell-Counting Kit 8 assay was performed to examine the effect of TNF-α on cell proliferation. Real-time polymerase chain reactions and western blot were used to detect vascular endothelial growth factor (VEGF) mRNA and protein expression. The Matrigel assay showed significantly greater total branching lengths and numbers of branches formed in the experimental groups treated with different concentrations of TNF-α compared with the control group. The decomposition times of the tubule structures were also significantly prolonged (P < 0.05). Treatment with 50 ng/ml TNF-α did not significantly change the proliferation of co-cultured cells, but it significantly increased the VEGF mRNA and protein expression levels (p < 0.05). In addition, the migration abilities of HUVECs and hDPSCs increased after co-culture with TNF-α (p < 0.05). TNF-α enhanced angiogenic ability in vitro in the co-culture system of hDPSCs and HUVECs.
... Coniglio et al 24 propõe o uso de uma ponta ultrassônica oval diamantada (Ellipson Tip, Satelec, Acteon group, France) para preparo de retentor após tratamento endodôntico. Pinos de fibra de vidro ovais são compatíveis para este tipo de preparo, indicado em canais ovais. ...
Ao longo das duas últimas décadas os pinos em fibra de vidro, ganharam um destaque especial, tanto
pelas suas propriedades mecânicas similares a da dentina, como pela estética quando associados a materiais
restauradores contemporâneos. Nos sistemas de pinos pré-fabricados em fibra recomenda-se a utilização
de fresas específicas para preparar o espaço para retentor e desta forma tentar adaptar o pino às paredes do
canal radicular. Esta circunstancia pode levar o clínico a realizar desgastes intra-radiculares além dos limites
aceitáveis, desta forma fragilizando e removendo excessivamente dentina sadia, além de poder causar acidentes
como perfurações ou desvios da trajetória original do canal. Por outro lado, pinos pré-fabricados em
fibra de vidro por apresentar formas padronizadas não permitem uma boa adaptação na grande maioria
dos canais. Perante a divergência em termos de adaptação do pino com o preparo do canal radicular, esta
falta de adaptação dos pinos reflete no seu deslocamento. Neste contexto, o objetivo deste artigo é propor
parâmetros clínicos atuais que vão desde o diagnóstico endo-restaurador à blindagem corono-radicular
simultânea, apresentação de técnicas atuais para o preparo, condicionamento e cimentação de retentores
intra-radiculares em fibra de vidro. Pode-se concluir que o preparo do canal para pino de fibra de vidro com
a técnica proposta e os dispositivos apresentados neste artigo permitem desgastes dentinários planejados
e específicos favorecendo a retenção mecânica destes pinos no espaço para retentor. O uso de materiais
adesivos e resinosos atuais permitem simplificação da técnica de blindagem corono-radicular simultânea.
Descritores: Técnica de preparo para retentor intra-radicular, Pinos de fibra de vidro, Blindagem
Corono-radicular Simultânea, Endodontia.
... Because the percentage of oval canals in the dentition is high (10), oval fiber posts have been recently introduced to provide better adaptation to the dentin walls and help avoid the use of circular fiber posts in oval canals (9). Using these posts results in reduced resin cement thickness (11,12), higher open dentin tubule scores (13), and improved post adhesion and retention strength (11,12). ...
The study aimed to evaluate the effects of different post morphologies and placement lengths on the fracture resistance of teeth with oval canal morphology that had been restored with crowns. Extracted mandibular premolars with similar dimensions were decoronated. After the root canal treatment, the teeth were mounted on acrylic blocks. Samples were randomly divided into four groups (n = 10 each). In groups C-10 and C-5, 10-mm- and 5-mmlong circular post spaces were created. In groups O-10 and O-5, 10-mm- and 5-mm-long oval post spaces were ultrasonically created. After post cementation, all specimens were restored with composite cores and prepared at height of 6 mm. Thereafter, all teeth were restored with crowns. After thermocycling, all specimens underwent fracture resistance testing. Oval posts and placement at 10-mm depth showed higher fracture resistance than circular posts and placement at 5-mm depth (P < 0.001). Increased post length and use of oval posts enhanced the fracture strength of teeth with oval canal morphology. Based on the results of this study, although the fracture resistance of teeth restored with crowns was enhanced by deep fiber post placement, the use of oval fiber post is recommended in cases where deep placement is impossible.
... Vários protocolos já foram propostos com o intuito de potencializar o desbridamento durante o PQM, como, por exemplo, o uso de soluções irrigadoras aquecidas 17 e técnicas de irrigações ultrassônicas [18][19][20] ; no entanto, esses estudos mostraram que o total desbridamento é um procedimento incerto. ...
Objetivo
Avaliar a eficácia das manobras de desbridamento no preparo químico-mecânico (PQM) quanto a limpeza e desinfecção no terço apical em molares humanos.
Material e método
Cinquenta raízes mesiais de molares inferiores humanos com dois canais radiculares foram inoculadas com E. faecalis e distribuídas aleatoriamente em cinco grupos (n=10). O PQM foi realizado com o sistema Protaper associado ao desbridamento com as limas Kerr #10 (G1 e G3) e as limas Kerr #15 (G2 e G4). O G5 representou o controle positivo, o qual foi submetido apenas ao PQM, sem receber o desbridamento. Outra variável foi o uso da medicação intracanal (MIC) à base de hidróxido de cálcio (Calen), que foi aplicada aos grupos G3 e G4. A irrigação foi feita com hipoclorito de sódio 2,5% e EDTA 17%. A análise da ação antimicrobiana se deu através da contagem das unidades formadoras de colônias (UFC).
Resultado
Foram aplicados o Teste Kruskal-Wallis (nas análises imediatas) e o Teste Mann-Whitney (nas análises mediatas), ambos com p=0,01. A análise imediata ao PQM apresentou-se sem diferença estatística entre os grupos (p=0,11). No G4 (#15 + MIC), os resultados das coletas mediatas foram estatisticamente significantes (p=0,01).
Conclusão
O desbridamento com as limas Kerr #10 e #15 não apresentou diferença significativa quanto à redução das colônias de E. faecalis quando comparado ao grupo em que não se realizou o desbridamento. Nos espécimes em que se aplicou a MIC, o desbridamento com a lima Kerr #15 (G4) foi mais eficiente do que a lima Kerr #10 (G3) em reduzir as UFC.
... [1] Thus, laboratory studies evaluated different parameters in order to obtain a reliable adhesion between resin cement and dentin through which the lifespan of reconstructions on endodontically treated teeth restored FRC and core could be prolonged. [1] The effect of canal preparation, [4] hybridization methods of root canal dentin, [5] resin cement, [5][6][7][8][9][10][11][12][13][14][15][16][17] polymerization methods for the resin cement, [18] and post configuration [6,19] have been studied and deemed to show effect on the bond strength of FRC posts. In fact, according to the clinical workflow, immediately after post cementation, the core is built up and it is prepared with rotating hand-pieces, which may cause torque forces to the newly cemented post until final polymerization reached. ...
This study assessed the effect of timing of core preparation and luting cement on adhesion of fiber-reinforced composite (FRC) posts on different levels of intraradicular dentin when cemented with either conventional dual-polymerized or self-adhesive resin cement. Single-rooted human teeth (N = 80) were endodontically treated and randomly divided into 2 groups (n = 40) according to resin cement: (a) Conventional dual resin cement (Variolink II, V) or (b) Self-adhesive resin cement (RelyX U200, R). They were further divided into two subgroups according to timing of core preparation (n = 20): (a) immediate (i) or (b) delayed (d). FRC posts (Cytec Blanco) were cemented and the roots were sliced into discs at the coronal, middle, and apical levels. Push-out tests were then performed in a Universal Testing Machine (1 mm/min). Data (MPa) were analyzed using three-way ANOVA and Tukey’s tests considering the factors ‘core preparation time’, ‘luting cement’, and ‘root level’ (α = 0.05). Type of luting cement (p < 0.001), time of core preparation (p < 0.001), and root level (p < 0.001) significantly affected the bond strength results. R cement was more significantly affected by core preparation time (Ri: 2.91 ± 1.1; Rd: 4.83 ± 1.68) compared to V cement (Vi: 2.92 ± 1.63; Vd: 2.65 ± 1.6) (p < 0.05). Coronal region demonstrated significantly higher bond strength values than those of middle and apical third in all groups (coronal: 4 ± 1.9; middle: 3.1 ± 1.4; apical: 2.4 ± 1.1) (p < 0.05). Adhesive failure between cement and dentin was the most frequent (64%) followed by adhesive failure between cement and post (18%). Delayed core preparation can improve bond strength of FRC posts to intraradicular dentin when cemented with self-adhesive cement compared to conventional dual-polymerized resin cement.
... Per questo motivo, l'approccio total-etch è ancora considerato il migliore nell'adesione dei perni in fibra per l'efficacia della mordenzatura con acido ortofosforico nel rimuovere il fango dentinale dalle pareti del canale radicolare [21]. Diversi studi hanno dimostrato che l'EDTA rimuove efficacemente il fango dentinale e i detriti sia dalla superficie dentinale sia dai tubuli dentinali lungo tutto il post-space [12,[22][23][24]. Tuttavia, nelle aree più profonde del post-space è difficile ottenere una superficie dentinale pulita e tutti i tubuli dentinali aperti, come mostrato dalle foto al SEM di questo studio in vitro ( fig. 1). ...
Valutare l’efficacia nella rimozione del fango dentinale dalle pareti dentinali intracanalari (dopo preparazione per l’alloggiamento del perno) utilizzando acido ortofosforico liquido al 37% rispetto alla formulazione in gel.Materiali e metodiPreparato l’alloggiamento del perno e deterso con EDTA al 10% per 60 secondi, i denti sono stati assegnati a quattro gruppi in base al tipo di trattamento impiegato: (A) acido ortofosforico (H3PO4) in gel al 36%; (B) H3PO4 liquido al 37% applicato con EndoVac; (C) H3PO4 liquido al 37% applicato con ago endodontico; (D) gruppo di controllo. È stata valutata al SEM la presenza di smear layer, detriti, residui di cemento e guttaperca e i tubuli dentinali aperti.RisultatiI risultati migliori per il trattamento effettuato sono stati ottenuti nel gruppo B, seguito dai gruppi A, C e di controllo.ConclusioniIl trattamento intracanalare con H3PO4 liquido al 37% applicato con un ago endodontico sembra produrre un substrato migliore per l’adesione della ricostruzione post-endodontica.
... A combination of chemical agents and ultrasonic instruments via acoustic streaming could significantly improve smear layer removal after endodontic instrumentation. However, the use of EDTA alone may result in incomplete debris removal; similarly, the use of ultrasonics without the aid of chemical agents produces packing of debris into the dentin tubules (299). There is general agreement that the removal of smear layers generated during root canal instrumentation is more efficient in the coronal and middle thirds than in the apical part of the root (300,301). ...
Dentin comprises the largest dental structure available for bonding. Because of its inherent morphological and physiological characteristics, reliable and durable resin–dentin bonding remains a challenging accomplishment that is subjected to multi‐factorial interferences. Adhesive technology has evolved significantly over the past decade, resulting in improved predictability of resin–dentin bonds. This article reviews the present knowledge regarding resin–dentin bonding from the perspective of the dentin substrate. Since another article in the previous issue of Endodontic Topics already covers dentin structure and composition, the intention is not to fully review these aspects. Instead, basic principles of current bonding strategies used by adhesive agents are presented. Specific attention is given to describing how the morphology and physiology of dentin affect existing bonding mechanisms, how some chemical treatments of dentin can affect its properties and bonding, and finally how bonding to root canal dentin is currently viewed and understood.
... Neither the post shape (with its respective cement thickness) nor the luting cement material had a significant effect on bond strength (push-out) (15). The use of oval points rather than round points to fill oval canals has the advantage of providing a cleaner space for the post, whereas instrumenting with rotary nickel-titanium instruments tends to create a central hole that sacrifices healthy tissue and weakens the root more (10,15,18). Luting thickness is not a factor that influences bond strength, according to another study which assessed luting thickness with cylindrical fibre posts of two different sizes. ...
The advantages of fibre posts over stainless steel posts have been demonstrated in numerous studies. For clinical success, various factors need to be taken into account in post-retained restorations.
A review was made of literature on fibre posts published from 2000 to February 2011, identified through searches of the PubMed/Medline databases.
The position of the tooth in the arch, ferrule size, proximal contact, periodontal support and restoration type are survival prediction factors that should be considered when performing post-endodontic restoration. Since fibre posts present good biomechanical behaviour as a result of their elastic modulus, which is similar to that of dentine, treatment failure occurs through decementation rather than because of root fracture, as occurs with metal posts. The shape of the post and, consequently, the thickness of the luting, can modify the retention capacity. Consequently, more anatomically-shaped posts have been developed, as have new techniques to reduce the volume of the dentine/cement interface: lateral condensation, surface remodelling or custom designs.
Different aspects of the preparation process can be modified to assist in improving fibre post retention, but further investigation, mainly clinical, is needed to acquire a better understanding of how different factors influence the long-term clinical behaviour of the posts. Key words:Fiber post, post shape, post adaptation, post retention, endodontics.
... 7 Several potential advantages of oval fiber posts over circular fiber posts have been reported, including reduced resin cement thickness, 8 better open dentin tubule scores, and increased adhesion. 9 Instead of using a rotary instrument to prepare the post space, a minimally invasive diamond-coated ultrasonic tip is used for the Ellipson oval fiber post (Ellipson tip; RTD/Satelec, Merigcac, France). 7 Although studies have demonstrated that oval fiber posts are more successful in oval root canals, 7,10 no study has compared the stress distribution of oval and circular fiber post systems. ...
The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs).
A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of 45° to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts.
FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups.
Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the post-dentin interface.
... Luting a post into an oval root canal can be problematic because proper cleaning of the canal is prevented and a greater amount of sound tooth tissue may be sacrificed during post space preparation in order to adapt the canal shape for achieving a good post fitting. The opportunity to use a dedicated ultrasonic tip for post space preparation for oval posts represents a possible advantage and has been suggested for a more conservative preparation [39]. Results from the present study clearly confirmed this, since the volume of the post space and the volume of the post itself were found to be lower for oval compared to circular posts. ...
Objectives
The purpose of the study was to evaluate by micro-computerized tomography (microCT) areas and volumes of post, cement, and voids/bubbles in the post space of oval-shaped premolars restored either with oval or circular posts.
Materials and methods
Twelve extracted premolars were divided into two groups according to the drill-fiber post system used: (1) GC Fiber Post Drill + circular post GC Fiber Post; (2) Ellipson tipTM + oval post Ellipson postTM. Each tooth was scanned using microCT, and areas and volumes of canal, post space, post, cement, and voids at coronal, medium, and apical level were calculated by using a three-dimensional visualization software. Two-way analyses of variance and Tukey tests were used for statistical analysis (p < 0.05).
Results
The area of voids was significantly greater at apical level of oval posts, but no difference was found between the levels among the groups. Regardless of post shape, the volume of voids and of cement was significantly higher at the coronal level. With oval posts, the total volume of cement was twice as much as with circular posts, and the difference was statistically significant.
Conclusions
Our results indicate that the volume of voids does not depend on post shape. Moreover, the microCT analysis demonstrated that the volume of cement was greater with oval posts compared to circular posts.
Clinical relevance
The microCT analysis provided interesting information on voids distribution and on the ratio between post shape and cement thickness. These results might address the clinician in the reconstruction of teeth with fiber posts.
... As reported in the literature, oval fiber dowels may have some advantages compared with circular fiber dowels, such as a reduced resin cement thickness, 20 better open dentin tubule scores, and increased adhesion. 21 Instead of using a rotary instrument to prepare the dowel channel, a minimally invasive diamond-coated ultrasonic tip is used to precisely prepare the dowel space for the Ellipson fiber post. 13 Although studies have demonstrated that oval fiber dowels are more successful in oval root canals, 13,16 no study has compared temperature changes during dowel space preparation between oval and circular fiber dowel systems. ...
Purpose:
The purpose was to evaluate temperature increases during dowel space preparations with oval and circular fiber dowel systems.
Materials and methods:
This study included 42 single-rooted human mandibular premolars. Roots were scanned with cone-beam computerized tomography (CBCT) to determine the ovoid root canal morphology. Root canals were treated with Ni-Ti rotary instruments and obturated. A second CBCT was taken to determine the thinnest dentin thickness of each root. Roots were randomly divided into two groups (n = 21) according to the fiber dowel system used: group 1, circular fiber dowel system (D.T. Light-Post); group 2, oval fiber dowel system (Ellipson Post). Dowel spaces were prepared using a circular fiber dowel drill and a diamond-coated ultrasonic tip with an oval section under water cooling until 9 mm dowel spaces were obtained. Temperature changes were recorded from the thinnest root surfaces using a FLIR E60 thermal imaging camera.
Results:
Temperature increases were significantly greater with the circular fiber dowel system than with the oval fiber dowel system (p < 0.05).
Conclusions:
Although both dowel systems generated high temperature increases on root surfaces, the relatively lower temperature increase associated with the use of oval fiber dowels in ovoid canals makes it preferable to the use of circular fiber dowels.
... The posts used in our study, like other fiber posts, have a good biomechanical behavior, which leads to reduce root fractures (19,20). In the Ellipson posts the cross-section shape is slightly rectangular with rounded corners; nevertheless, they are called by the manufacturer and known in the current literature as oval posts (6,7,18). The ratio between the larger and smaller diameters in a cross section is 1.4 in these posts. ...
Oval fiber posts attempt to provide better adaptation to root canals. The hypothesis of this study was that there are no differences in adaptation of oval and circular fiber posts to canal walls.
Posts were inserted in 20 canals; 10 were oval, and 10 were circular. The posts were cemented with composite cement. Coronal, middle, and apical sections were observed through a microscope. The space occupied by the post and the maximum distance between it and the canal wall were calculated. The 2 groups were compared with analysis of variance. In all the analyses the level of significance was set at P < .05.
The proportion of space occupied by the post showed no significant differences (P > .05). The cement layer was thinner in the apical region in oval posts (P < .05).
Oval posts do not adapt better than circular posts to the morphology of oval canals.
... 23,24 For ovoid-shaped canals, the use of an ultrasonic oval-shaped tip has been suggested for a more conservative post space preparation ( Fig 3A). 25 ...
This literature review summarizes the most recent and reliable evidence on post systems. A search was limited to review articles published over the last 10 years in dental journals with an impact factor. Papers cited in the initially retrieved review articles were also included if significant. Preservation of tooth tissue, presence of a ferrule effect, and adhesion are regarded as the most effective conditions for long-term success of post-endodontic restorations. Adhesively luted fibre-reinforced composite post restorations have demonstrated satisfactory survival rates over relatively long follow-up periods. The clinical effectiveness of such restorations has been mainly ascribed to the more biomimetic behaviour of fibre-reinforced composite posts that reduces the risk of vertical root fractures. The most common type of failure when using fibre posts is post debonding and it is generally agreed that achieving stable adhesion to intraradicular dentine is more challenging than to coronal dentine. Several factors related to endodontic treatment, root canal shape, post space preparation, post translucency, adhesive cement handling and curing may have an influence on the outcome of the luting procedure. The most reliable results in fibre post cementation are obtained by etch-and-rinse adhesives in combination with dual-cure resin cements. The use of self-adhesive resin cements has also been proposed. Simplification is an obvious advantage of these new materials. However, the durability of their bond still needs to be verified with long-term clinical studies. Several techniques for pre-treating the fibre-reinforced composite post surface have been tested with the aim of improving the bond strength at the post-core and post-cement interfaces. Silicoating followed by silanization currently appears to be the most effective and convenient method for this purpose. In conclusion, the available evidence validates the use of fibre posts as an alternative to metal posts and preferably to other tooth-coloured posts, such as zirconia dowels, in the restoration of endodontically treated teeth. Longer term clinical trials are expected to further strengthen this evidence.
Introduction
Preparation of flattened root canals using reciprocating or rotary nickel-titanium (NiTi) instruments associated with the Flatsonic ultrasonic tip was evaluated by micro-computed tomographic (micro-CT).
Methods
Twenty-four flattened distal canals of mandibular molars with a buccolingual diameter 4 or more times larger than the mesiodistal diameter were selected. The root canals were randomly divided into two experimental groups for preparation: Reciproc Blue (RB) 40/.06 file in reciprocating motion or ProDesign Logic (PDL) 40/.01 and 40/.05 files in rotary motion (n = 12). A complementary preparation was performed with the Flatsonic ultrasonic tip for both preparations. Micro-CT scanning at a resolution of 8.74 μm was performed before and after preparation with the NiTi instruments and after use of the Flatsonic tip. The percentages of increase in volume, debris and uninstrumented surface were analyzed. The data obtained were submitted to paired and unpaired t-test, ANOVA and Tukey (α = 5%).
Results
The percentage increase in volume, debris and uninstrumented surface was similar between RB and PDL, in entire root canal (P > .05). PDL promoted a lower percentage of debris in the cervical third, and lower percentage of increase in volume in the apical third in comparison with RB (P < .05). Flatsonic decreased debris and uninstrumented surface after PDL preparation in all thirds (P < .05). After preparation with RB, the Flatsonic decreases the debris in cervical third and uninstrumented surface in the cervical and middle thirds (P < .05).
Conclusions
Preparation of flattened root canals using Reciproc Blue or ProDesign Logic produced high percentage of debris and uninstrumented surface. Flatsonic ultrasonic tip significantly improved the cleaning of flattened root canals.
Statement of problem
Whether the amount of the endodontic obturation material remnants in a root canal prepared for a post is related to variations in the anatomic shape of the canal or whether it varies in different parts of the post space is unclear.
Purpose
The purpose of this in vitro study was to estimate the extent of root canal contamination with remnants of the obturation material after post space preparation in relation to the anatomic shape of the root canals by means of microcomputed tomography.
Material and methods
Fifty freshly extracted teeth were divided into 5 test groups with respect to the root anatomy of different tooth types. The root canals were shaped and obturated with gutta percha. The space for the glass fiber post was prepared with standardized drills, and all specimens were scanned by microcomputed tomography. The areas of residual obturation material on the root canal walls in the coronal and apical parts of the prepared post space were estimated by using 3D visualization software. Parametric and nonparametric dispersive analysis (analysis of variance and Kruskal-Wallis) and Wilcoxon tests were used for statistical data evaluation (α=.05).
Results
The estimates of the root canal surface areas contaminated with residual obturation material after post space preparation were significantly larger in premolars (P≤.01), as compared with mandibular incisors and with the palatal roots of maxillary first molars. The contamination areas in different parts of the root canal (apical and coronal) reported significant differences within and between the test groups.
Conclusions
The extent of root canal contamination with remnants of endodontic obturation material after post space preparation was related to the anatomic shape of the roots and varied in the coronal and apical parts of the prepared post space.
Preparos para retentores intra-radiculares mais conservadores evitam desgaste desnecessário da estrutura dentinária, requer menos cimento e podem melhorar a retenção adesiva do pino. Assim o objetivo deste estudo foi avaliar a espessura de cimento e a resistência adesiva de pinos de fibra de vidro cônicos em preparo para retentor intra-radicular realizados com uma ponta ultrassônica desenvolvida. Trinta incisivos laterais superiores foram preparados com limas reciprocantes Wave One Gold (Dentsply Sirona, Ballaigues, Suiça) e aleatoriamente divididos em 2 grupos (n=15) de acordo com a técnica de preparo para pino: grupo US foram preparados com uma ponta ultrassônica desenvolvida, e grupo WP (controle) com a broca recomendada pelo fabricante do pino. Os pinos de fibra de vidro cônicos WhitePost DC 0.5 (FGM, Joinville, SC, Brasil) foram cimentados utilizando cimento resinoso dual nos terços cervical e médio do canal radicular. Isto posto, todos os espécimes foram seccionados transversalmente em três seções (cervical, média e apical do pino) para análise da área de cimento resinoso ao redor do pino que foi calculada através do programa AutoCAD, em seguida, para avaliar a resistência adesiva, o teste de cisalhamento por extrusão foi aplicado através de uma maquina de ensaio universal numa velocidade média de 0.5 mm/min até o deslocamento do conjunto restaurador intra-radicular e o tipo de falha avaliado por estereomicroscopia. A comparação entre grupos e entre terços da área de cimento e resistência adesiva foram analisadas pelo teste t independente e Anova com Tukey; e os tipos de falha entre os grupos por Mann-Whitney, todos com nível de significância de 5%. No grupo ultrassônico foi observado a menor quantidade de cimento (p<0.05) e a resistência adesiva nos diferentes grupos e terços se manifestou maior somente no terço apical do grupo ultrassônico (p<0.05). Falha adesiva entre cimento e dentina foi a mais prevalente do terço cervical e apical do grupo US e cervical de grupo WP. Falha adesiva entre cimento e pino foi a mais prevalente nos demais terços. Conclui-se que o preparo para retentor com a ponta ultrassônica desenvolvida requer menor quantidade de cimento e influencia na melhor resistência de união no terço apical do pino de fibra de vidro.
Palavras-chave: Pinos de fibra de vidro. Espessura de cimento. Resistência adesiva. Preparo para retentor intra-radicular.
One of the main objectives of endodontic treatment is the thorough preparation of the root canal system and proper obturation for obtaining a three-dimensional seal. To achieve this goal, clinicians must have a comprehensive knowledge of the normal anatomy of the relevant root canal system and its common variations. Cross-sectional root canal configurations have been classified as round, oval, long oval, flattened, or irregular. The oval shaped canals should have a different approach regarding management compared with normal root canal configurations. The recognition of oval configurations determines that a different approach be applied in cleaning, shaping and obturation. Because of the importance of executing a suitable treatment option for oval shaped canals, a comprehensive review of published information is vital. The aim of this study was to address the definition, prevalence, and treatment protocols for oval shaped canals.
Objetivo: Avaliar ex vivo a adaptação dos pinos de fibra de vidro cônicos WhitePost DC 0.5 em canais circulares preparados com a ponta de ultra-som PostPrep 0,5 e a broca WhitePost DC 0.5. Materiais e métodos:: 30 incisivos laterais superiores foram selecionados, instrumentados e obturados seus terços apicais. Posteriormente divididos aleatoriamente em dois grupos experimentais de acordo com o tipo de preparação do espaço para retentor intra-radicular, sendo Grupo 1 (15 raízes): preparo com ponta de ultra-som PostPrep 0,5 e Grupo 2 (15 raízes): preparados com a broca WhitePost DC 0,5. Os pinos cônicos foram cimentados com cimento resinoso em ambos grupos. Foram obtidos cortes transversais de cada raiz (terço cervical e apical do pino). As seções foram observadas em estereomicroscópio com aumento de 40x. Mensurou-se a adaptação do pino às paredes dentinárias, onde a espessura do cimento resinoso e a área do conduto ocupada pelos pinos foram avaliadas. Os testes estatísticos utilizados foram t-student e Mann-Whitney com nível de significância de 5%. Resultados: Nos terços cervicais observou -se uma fina camada de cimento resinoso dual em ambos os grupos, sem diferença (p>
0,05) e uma grande porcentagem de área ocupada pelo pino no canal radicular de 93,12% e 90,79% nos grupos respectivos. Já no terço apical do pino foram observadas menor espessura de cimento resinoso no grupo 1, com relação ao grupo 2 (p <0,05), consequentemente uma melhor adaptação do pino no conduto radicular. Além disso, os pinos do grupo 1 tiveram uma maior área ocupada de 83,14% e 69,57% no grupo 2, com diferença estatisticamente significativa entre os grupos (p <0,05). Conclusões: Em condutos circulares, nos terços apicais, a técnica preparo ultra-sônica permitiu uma melhor adaptação e uma maior área ocupada pelos pinos cônicos quando comparado com preparos rotatórios.
Palavras-chave: Endodontia; pinos de fibra de vidro; preparo para retentor intra-radicular.
Blindaje corono-radicular simultáneo en endodoncia: de la instrumentación radicular a la restauración definitiva.
Blindagem corono-radicular simultânea em Endodontia: do preparo radicular à restauração definitiva.
Resumen
La restauración de los dientes tratados endodónticamente genera hasta los días actuales discusiones y controversias entre clínicos e investigadores. En este contexto, el uso de pernos intrarradiculares de fibra de vidrio asociados a restauraciones directas en resina compuesta se presenta como una excelente alternativa de tratamiento viable, especialmente por las buenas propiedades mecánicas y estéticas de estos pernos de fibra en
asociación con estos materiales resinosos actuales. El objetivo de este trabajo es presentar por medio de casos clínicos una técnica de instrumentación y restauración simultánea del sistema de conductos radiculares, que abarca desde el diagnóstico endo-restaurador planeado, instrumentación mecanizada ideada visando la instalación de retentor intrarradicular, construcción del muñón culminando con la restauración definitiva del
diente tratado, considerando los requisitos y aspectos clínicos, mecánicos y biológicos del diente tratado endodónticamente. En los controles clínicos ambos casos presentaron restaurados, una normalidad clínica, se encontraron asintomáticos y en oclusión. Radiográficamente se pudo observar reparación ósea y ausencia de áreas raciolúcidas relacionadas al diente tratado, concluyendo con éxito clínico y radiográfico los casos y la técnica presentada.
Palabras clave: Endodoncia, perno de fibra de vidrio, ultrasonido EV-PREP, resinas bulk fill, Blindaje corono-radicular simultáneo.
Abstract
The restoration of endodontically treated teeth, generates until today, discussions and controversies between clinicians and researchers. In this context, the use of intracanal fiber posts associated with direct restorations in composite resin glass is presented as an excellent alternative of viable treatment, especially by excellent mechanical and aesthetic properties of these post fiber in association with these current resinous materials .
The aim of this paper is to present through clinical cases instrumentation technique and simultaneous restoration of root canal system, ranging from diagnosis endo-restorative planned, mechanized instrumentation designed aiming at the installation of intraradicular retentor, construction stump culminating the final restoration of the treated tooth, considering the requirements and clinical, mechanical and biological aspects of endodontically treated tooth. In clinical controls both cases had restored normal clinic, asymptomatic and normal occlusion.
Radiographically was observe absence of radiolucent areas and bone repair related to the treaty, concluding with clinical and radiographic success cases and the technique presented tooth.
Keywords: Endodontics, fiberglass post, corel resin, bulk fill resins, simultaneously shielding root-crown.
Achievement of reliable bonding and effective adhesion inside the root canal is an issue of great interest. The selection of an adequate adhesive strategy inside the root canal is still a matter of debate, and data of studies demonstrate contradictory results.
After post space preparation, the dentin walls are covered by heavy smear layer containing rough debris and remnants of sealer and gutta-percha that may hamper bonding to the root canal dentin and highlight the importance of smear layer modification inside the root canal. In this aspect, the adhesive strategy might play an important role for adhesively luted fiber posts. Therefore, scientific data that have evaluated the performance of various luting materials for bonding fiber posts will be presented and analyzed.
Moreover, methods for cleaning the root canal and irrigation protocols after post space preparation and their effects on bond strength of different adhesive strategies are important clinical issues, and these aspects will also be summarized from a scientific and a practical point of view.
Statement of problem:
Fiber posts in conjunction with resin cements are widely used to provide retention in endodontically treated teeth. The bond strength of restorative materials to root canal dentin is an important issue for the long-term success of restorative procedures. The push-out test is widely used to measure the bonding between the post and radicular dentin.
Purpose:
The purpose of this in vitro study was to evaluate the effect of erbium-doped yttrium aluminum garnet (Er-YAG) laser treatment of dentinal walls on the bond strength of circular and oval fiber posts luted in oval root canals.
Material and methods:
Forty mandibular premolar teeth were endodontically treated and restored with 2 different intracanal post systems. Push-out tests were performed and data were analyzed by using 2-way analysis of variance and post hoc Bonferroni tests.
Results:
Laser pretreatment of dentinal walls resulted in higher push-out bond strength than that of the nonlasered groups (P<.05). Oval fiber posts showed significantly higher push-out bond strength values than those of circular fiber posts in the coronal region (P<.05). In the apical region, no statistically significant difference was noted among the groups regarding push-out bond strength (P>.05).
Conclusions:
The laser pretreatment with an oval ultrasonic tip of an oval fiber post system improved bonding to root canal dentin when compared with a circular post system with conventional preparation.
Introduction:
The aim of the present study was to evaluate the effects of post space preparations with circular and oval post drills and the placement of oval and circular posts on the fracture strength of roots with oval canals.
Methods:
Seventy mandibular premolars with oval root canals were decoronated. Fourteen teeth were used as a control group (group 1), and the root canals of the remaining teeth were prepared up to size #30. The root canals were filled, and the samples were randomly divided into 4 experimental groups as follows: post space preparation with circular-shaped drills (group 2), post space preparation with oval-shaped drills (group 3), circular post placement (group 4), and oval post placement (group 5). A fracture strength test was performed on each specimen, and the data were statistically evaluated using 1-way analysis of variance and Tukey post hoc tests.
Results:
The fracture strengths of the circular posts-placed group were higher than those of the oval post-placed group (P < .001). The post space preparation using oval-shaped drills significantly decreased the fracture strength of the roots compared with the control group (P < .001).
Conclusions:
Within the limitations of the present study, oval posts did not provide a higher fracture resistance to endodontically treated roots with oval canals compared with circular posts. Therefore, clinicians should be aware that oval posts are similar to circular posts in terms of enhancing the fracture resistance of roots with oval canals.
The aim of this in-vitro study was to evaluate the bond strength of fiber posts cemented in a root canal filled using various root-canal obturation techniques. A total of 33 monoradicular samples, treated endodontically, were randomly assigned to three groups according to the root-canal obturation technique: group 1, continuous-wave technique; group 2, plastic-obturator-core technique; and group 3, cross-linked gutta-percha obturator-core technique. Fiber posts were luted in each sample and each was sectioned perpendicular to the post axis. The push-out test was performed using a universal machine and the maximum failure load was recorded in MPa mm(-2) . Several samples were randomly chosen for scanning electron microscopy evaluation. The mean debris and dentinal tubule-opening scores were calculated separately in the coronal and apical portions. Bond strength was significantly higher in group 1 than in groups 2 and 3. Debris scores were significantly higher in the apical portion of groups 2 and 3 than in group 1. Within the limitations of this study it can be affirmed that thermoplasticized alpha gutta-percha seemed to worsen the cleaning of post-space walls and hence reduced fiber-post bond strength.
Aim:
To investigate the effects of various cleaning methods, luting agents and preparation procedures on fibre post retention.
Methodology:
In total, 156 human canines were allocated to twelve groups. Teeth were decoronated, instrumented and root filled using warm vertical gutta-percha compaction. Post space preparation was performed in 78 roots using the dedicated preparation drills of the DT Light Post SL system [group post drill (PD)]. Gutta-percha was removed from the other 78 roots using a round bur (RB) (group RB). Within each of these two groups, 26 root canals were rinsed with 1% NaOCl (control), 26 were cleaned using rotating brushes and pumice powder, and 26 were sandblasted with Al(2) O (3) (50 μm) using an intraoral device. Cleanliness of each root canal was investigated using an operating microscope (n = 24) and scanning electron microscope (n = 2). Fibre posts were inserted using self-adhesive resin cement (SmartCem2) or core build-up material (CoreX Flow/XP Bond). Pull-out force was measured using a universal testing machine. Statistical analyses were performed using three-way anova and Tukey's HSD post hoc tests.
Results:
Root canal cleanliness was not affected by the cleaning method (P = 0.618, chi-squared test). Pull-out force for fibre posts was significantly affected by the cleaning method (P = 0.008), the luting agent (P < 0.0005) and the preparation procedure (P < 0.0005, three-way anova). RB group demonstrated significantly higher pull-out forces [399 (88) N] compared with PD group [287 (105) N]. Posts that were inserted using CoreX Flow/XP Bond exhibited significantly higher pull-out forces [370 (62) N] compared with posts inserted using SmartCem2 [315 (141) N].
Conclusion:
The different cleaning methods did not lead to significant differences in root canal cleanliness and did not enhance fibre post retention inside the root canal. However, post space preparation using a RB might be beneficial for improving retention, especially when self-adhesive cements are used. The use of the core build-up material CoreX Flow/XP Bond instead of the self-adhesive resin cement, SmartCem 2, resulted in significantly higher pull-out force.
The aim of this study was to evaluate the bond strength of fiber posts luted with a one-step self-etching adhesive with the push-out test after phosphoric acid conditioning of the root dentin. Thirty-six single-rooted teeth were endodontically treated. Teeth were sectioned perpendicularly to the cementoenamel junction, and a 10-mm post space was prepared with a calibrated bur. Specimens were then divided into three groups according to the adhesive protocol: A, total-etch three steps; B, self-etch one step; and C, 32% phosphoric acid conditioning and self-etch one step. Fiber posts were luted with self-curing resin-based cement. Teeth were cut in 1-mm slices and pushed until failure with an Instron machine. Results were statistically analyzed with the ANOVA and Bonferroni tests (P < .05). Two additional specimens from each group were examined under the scanning electron microscope (SEM). The 32% phosphoric acid significantly influenced the push-out bond strength of fiber posts luted with self-etch adhesives (P < .05). SEM analysis showed a continuous hybrid layer with resin tags and lateral branches in groups A and C, while group B showed smear layer dissolution with poor infiltration of the tubules.
This study aimed at evaluating the post-root dentin push-out bond strength of circular and oval posts luted in oval-shaped canals with two different resin cements. Twenty extracted premolars with oval-shaped canals were selected, endodontically instrumented and obturated. The teeth were divided into two groups according to the drill used for post-space preparation and to the post shape (Ellipson oval tip + post and MTwoPF + DT Light-Post). Each group was then subdivided into two subgroups according to the cement (Gradia Core and Corecem Automix). The post-dentin bond strength was evaluated with the thin-slice push-out test. The bonded surface area was calculated for each post shape with an appropriate geometric formula in order to express the retentive strength in megapascal. Push-out strength data were analyzed with the Kruskal-Wallis ANOVA. The results showed that neither the drill-post system nor the cement significantly affected the push-out strength. The means (SD) of the push-out bond strengths in the experimental subgroups were the following: 11.79 MPa (4.77) for Gradia Core/Ellipson tip and post, 13.36 MPa (5.16) for Gradia Core/MtwoPF and DT Light-Post, 11.18 MPa (2.58) for Corecem Automix/Ellipson tip and post, and 10.91 MPa (3.89) for Corecem Automix/MtwoPF and DT Light-Post. In conclusion, circular and oval posts achieved similar retentive strengths in oval canals.
Adhesives and lining/base materials should relieve the stresses concentrated at the tooth/restoration interface. The study aimed at comparing the mechanical properties of eight adhesives and six glass-ionomer cements (GICs). The adhesives were applied on dentin disks, whereas 2 mm x 3 mm x 2 mm GICs specimens were prepared in a teflon mold. Vicker's hardness (VH), elastic modulus (E), creep (Cr) and elastic work (We/Wtot) were measured with a micro hardness indenter. One-way ANOVA and Tukey's test were used to compare the mechanical properties within each materials' type and among the materials' classes. Enamel and dentin were used as references. Significant differences were detected within each materials' type and among the materials' classes and enamel and dentin. GICs were superior to adhesives in VH and E and showed a VH similar to dentin. GICs presented mechanical properties more similar to enamel and dentin than adhesives.
To determine the fracture resistance of different sizes of standardized single fiber posts and the combinations of multiple small experimental posts.
Single posts in three different sizes (1, 2 and 3; DT Light Posts, RTD; DT), as control, and seven different combinations of experimental small posts (Abrasive Technology), reproducing the sizes of several endodontic files were cemented in endodontic resin blocks. The combinations of small posts were made combining 2-4 small posts so as to reach the sizes of standardized DT posts. The posts were loaded at an angle of 45 degrees to the long axis of the block using a crosshead speed of 1 mm/minute until specimen failure. Ten posts/combinations were tested. Statistical analysis was performed using one-way ANOVA followed by Tamhane test for the post hoc comparisons (P < 0.05).
For the single posts, fracture resistance increased when increasing the diameter of the post. The use of multiple posts resulted in fracture resistances comparable to that of the single post for two of the three diameters studied (DT1 and DT2). For the largest diameter (DT3), the use of multiple posts resulted in lower fracture resistances than did the single post.
The aim of this study was to observe the existence and assess the quality of obturation of uninstrumented recesses in oval canals.
The balanced force technique was used in two groups of oval canals in human mandibular incisors. The canals in group 1 were enlarged to conventional sizes, whereas canals in group 2 were enlarged more widely. All canals were obturated with cold laterally condensed gutta-percha. Two horizontal sections were cut in the apical portion of each filled root. Images of the cross-sections were scanned and analysed using the KS100 Imaging system.
Uninstrumented recesses appeared in 13 (65%) oval canals. The recesses in five of these 13 canals were obturated without visible voids. The recesses in the other eight canals were either obturated with visible voids or completely unfilled. The percentage of filled area was significantly higher in group 1 than in group 2 (P < 0.05).
Uninstrumented recesses may be left in many oval canals after preparation using the balanced force technique and these recesses may often not be completely obturated with cold laterally condensed gutta-percha.
To evaluate in vitro the dentin morphology in root canals in terms of tubule orientation, density and increase in surface area after etching.
Thirty anterior teeth were divided in 3 groups at random: the samples of Group 1 were used to study tubular morphology in SEM. Groups 2 and 3 samples were etched with 32% phosphoric acid. The teeth in Group 2 were examined by SEM without further treatment. The samples in Group 3 were treated with a bonding system and fiber posts were luted into the canal. These teeth were then processed for evaluation of hybrid layer formation and resin tags in dentin tubules. The observations were made according to location in the root dentin, tubule density was estimated, and the increase in area available for bonding after etching was calculated.
The observations revealed variability in tubule density and orientation within different areas of any one sample. Statistically significant differences in the density of tubules were found depending on location. The dentin surface area available for bonding increased by 202% after etching in the cervical third, 156% in the middle third, and 113% in the apical third of the root dentin. Group 3 samples showed that the thickness of the hybrid layer depended on the density of tubules. In the sectors with a low density of tubules, the hybrid layer was significantly thinner than in areas with a higher density of tubules. The increase in dentin surface area might be responsible for the enhanced bond strength after acid etching, but not all areas exhibited equal responses to etching.
Post placement in oval-shaped root canals implies the sacrifice of sound dental tissue to adapt the canal shape to fit the post, which can result in one of several significant complications. A semidirect, single-visit, chairside procedure is proposed, which permits the use of an almost anatomically shaped post, starting from a preformed fiber-reinforced composite root canal post of the largest size commercially available. The utilization of this post capitalizes on the advantages of both the fiber post and the anatomical post in oval- and ribbon-shaped canals to provide restoration of endodontically treated teeth.
During the past few decades endodontic treatment has benefited from the development of new techniques and equipment, which have improved outcome and predictability. Important attributes such as the operating microscope and ultrasonics (US) have found indispensable applications in a number of dental procedures in periodontology, to a much lesser extent in restorative dentistry, while being very prominently used in endodontics. US in endodontics has enhanced the quality of treatment and represents an important adjunct in the treatment of difficult cases. Since its introduction, US has become increasingly more useful in applications such as gaining access to canal openings, cleaning and shaping, obturation of root canals, removal of intracanal materials and obstructions, and endodontic surgery. This comprehensive review of the literature aims at presenting the numerous uses of US in clinical endodontics and emphasizes the broad applications in a modern-day endodontic practice.
The theoretical possibility of using a standardized endodontic preparation and obturation technique in premolars was investigated by measuring the widths of the roots and root canals of 80 teeth. Providing the canals were not too curved, circular-shaped preparations might be made with acceptable frequency in the apical 2 to 3 mm of maxillary second premolars and mandibular premolars. Theoretically,this technique is not generally applicable in maxillary first premolars.
The theoretical possibility of using a standardized endodontic preparation and obturation technique in molars was investigated by measuring the widths of the roots and root canals of 40 teeth. Providing the canals were not too curved, circular-shaped preparations might be made with acceptable frequency only in the apical 1 to 3 mm of the buccal roots of maxillary molars and at the 1-mm level from the apex in the distal roots of mandibular molars. Theoretically, this technique is not generally applicable in molars.
One hundred six human mandibular left and right first premolars, previously extracted due to nonrestorable caries, periodontal disease, or orthodontic reasons, were sectioned perpendicular to the long axis of the root starting at the cementoenamel junction. Three-millimeter sections were made with an ultrathin separating disc to the level of the anatomical apex. After 1 day in 5.25% NaOCl, each section was rinsed in phosphate-buffered saline, evaluated with a stereomicroscope, and photographed. The slides were projected and the shape of the canal, incidence of multiple canals, level of bifurcation, and any other variant anatomy were recorded. Seventy-six percent of the premolars demonstrated Type I canals and 24% contained Type IV. The shape of the canals was predominantly oval or round. An interesting finding was the number of C-shaped canals which were associated predominantly with Type IV canal systems. This occurred in 14% of the roots.
The purpose of this study was to evaluate the integrity of resected root-end surfaces of extracted human teeth after using ultrasonic tips at low or high frequencies for root-end preparation. Thirty bilaterally matched pairs of single-rooted human teeth had root-end resections using a low-speed diamond saw and were examined for root-end cracks. The matched pairs of teeth were then divided into two experimental groups, with one member of each pair being placed in each group. In group 1, root-end preparations were made with an ultrasonic tip on the lowest frequency setting. The preparations in group 2 were done on the highest power setting. Two investigators again examined the resected root-ends using a stereomicroscope at x20 to x63 and recorded the numbers, types, and location of the cracks. Three types of cracks were observed: canal cracks, intradentin cracks, and cemental cracks. There were significantly more root-ends with cracks after ultrasonic root-end preparation than after root-end resection only. In root-ends that had any cracks, significantly more canal cracks per root occurred when the ultrasonic tip was used on the high-frequency setting for root-end preparation than when the ultrasonic tip was used on the low power setting.
The aim of this study was to investigate the dentine cutting action of a CT4 and SJ4 radicular preparation inserts (Excellence in Endodontics/Analytic Technology, Orange, CA, USA) used in a Piezon Master 400 ultrasonic handpiece (Electro Medical Systems SA, Nyon, Switzerland). Calibration of the ultrasonic inserts was carried out at minimum, medium and maximum power settings using light microscopic measurement of the tip displacement amplitudes (x120 mag). Polished dentine samples were instrumented, at monitored loads, at the three chosen power settings, to produce uniform dentine cuts. The resultant dentine debris was collected for SEM analysis, and comparison with that produced by rotary instruments. The depth of dentine cut was measured at x30 magnification. Fracture of the SJ4 insert was noted at medium power setting. Results revealed a significant increase in both displacement amplitude and depth of dentine cut with power setting (ANOVA P < 0.001). Dentine chip size increased with power, and differed in structure and appearance from those produced by rotary instruments. In conclusion, ultrasonic cutting is influenced significantly by power setting, and dentine chip formation is fundamentally different to rotary instrumentation.
To investigate the root and canal morphology of 351 mandibular permanent molars collected from an indigenous Thai population.
The cleaned teeth were accessed, the pulp dissolved by sodium hypochlorite under ultrasonication and the pulp system injected with Indian ink. The teeth were rendered clear by demineralization and immersion in methyl salicylate. The following observations were made: (i) number of roots and their morphology; (ii) number of root canals per tooth; (iii) number of root canals per root; (iv) root canal configuration in each root using Vertucci's classification, with additional modifications; and (v) presence and location of lateral canals and intercanal communications.
Of 118 mandibular first molars, 13% had a third disto-lingual root. In three-rooted teeth, 80% of the main distal roots and 100% of the disto-lingual roots had type 1 canal systems. Of 60 mandibular second molars, 10% had C-shaped roots, the majority of which had type 1 (33%) or type IV (33%) canal systems. Of 173 third molars, 68% had two separate roots, 20% had fused roots and 11% had a single C-shaped root; the majority had two canals (61%).
This study suggests that Thai molars exhibit features of both Caucasian and Chinese teeth.
This study was designed to determine the efficiency of hand and rotary instruments in shaping oval root canals. Seventy-five oval canals were equally divided into three groups. The apical third was prepared with rotary LightSpeed instruments either to size 52.5 (mandibular incisors) or to size 57.5 (distal root of mandibular molars). The middle third with an oval cross-section was shaped with Hedström hand files using circumferential technique, with 6% taper rotary Hero files in a circumferential filing movement or with rotary LightSpeed instruments in a step-back technique. Instrumentation was performed under clinical conditions in a phantom head. The teeth were sectioned at two levels in the middle third of the root. An assembly technique allowed comparing the canal outline before and after instrumentation. The photographed root sections were superimposed and traced under a stereomicroscope. The ratio of prepared to unprepared canal outline was calculated for each section. The lowest values were observed in the LightSpeed group (mean: 0.42; 95% confidence interval (CI): 0.37; 0.47). Significantly higher values were recorded in the Hero group (mean: 0.58; 95% CI: 0.53; 0.64) and in the Hedström group (mean: 0.56; 95% CI: 0.49; 0.62). No instrumentation technique was capable of completely preparing dentin walls of oval root canals. Circumferential filing of the middle third of oval root canals with either 6% taper Hero files or conventional Hedström hand files gave comparable results.
The purpose of this in vitro study was to examine dentinal erosion caused by final irrigation with EDTA and NaOCl.
Twenty-five single-rooted human teeth were instrumented with rotary nickel-titanium Series 29 Profile Instruments. The teeth were divided into five groups and subjected to final irrigation as follows: group A, irrigated with 6% NaOCl (3 mL) for 2 min; group B, 15% EDTA (3 mL) for 1 min; group C, 15% EDTA (3 mL) for 1 min, followed by 6% NaOCl (3 mL) for 2 min; group D, 15% EDTA (3 mL) for 3 min and group E, 15% EDTA (3 mL) for 3 min, followed by 6% NaOCl (3 mL) for 2 min. Photomicrographs of dentinal walls were produced using a scanning electron microscope (3000 x) at 1, 3 and 6 mm from the apex. The amount of debris and dentinal tubule diameter were evaluated, and values were statistically analysed using one-way ANOVA and Fisher's PLSD test.
When the root canal was irrigated with 15% EDTA alone, the dentine had a smooth and plane appearance, and dentinal tubule orifices were regular and separated. When the root canal was irrigated with EDTA followed by NaOCL the dentine was eroded and the dentinal tubule orifices were irregular and rough. Dentinal tubule diameter increased to 3.43 +/- 0.23 microm in group C and to 3.93 +/- 0.44 microm in group E. Significant differences were observed between groups B and C, and between groups D and E (P < 0.05). However, more debris was removed by irrigation with EDTA followed by NaOCl than with EDTA alone (P < 0.05).
Final irrigation with 6% NaOCl accelerates dentinal erosion following treatment with 15% EDTA.
The aim of this study was to compare the preparation of oval distal root canals in mandibular molars using three different nickel-titanium (NiTi) instruments: Lightspeed (Lightspeed Inc., San Antonio, TX, USA). ProFile .04 (Maillefer Ballaigues. Switzerland) and Quantec SC (Tycom, Irvine, CA, USA).
Three groups of 20 extracted mandibular molars with oval distal root canals were embedded in a muffle system as described by Bramante et al. (1987) and modified by Hülsmann et al. (1999). Preparation of the root canals was performed with particular emphasis on the buccal and lingual extensions of the oval shape. The following parameters were evaluated: comparison of pre- and postoperative photographs with regard to the buccal and lingual extensions of the preparation, safety issues (file fractures, perforations, apical blockages, loss of working length), cleaning ability (SEM investigated using a 5-score system for remaining debris and smear layer) and working time.
Superimposition of pre- and postoperative cross-sections in the majority of specimens revealed uninstrumented or incompletely instrumented buccal or lingual extensions (Lightspeed and Quantec SC, 56.7%; ProFile .04, 55%) For debris removal, Quantec SC achieved the best results (54.2% scores 1 and 2), followed by ProFile .04 (52.5%) and Lightspeed (46.7%). Preparation resulted in substantial smear layer covering the canal walls for every system (ProFile .04, 38.3%; Quantec SC, 36.6%; Lightspeed, 28.3%). Differences between the three systems were not significant for any of the parameters investigated. Preparation with Lightspeed resulted in two fractured instruments; with Quantec SC. two apical blockages occurred. With ProFile .04, no complications were noticed. Mean working time was shorter for ProFile .04 (261.2 s) than for Quantec SC (272.4 s) and Lightspeed (338.9 s); the differences were not significant.
The flexibility of the NiTi instruments investigated in this study did not allow controlled preparation of the buccal and lingual extensions of oval root canals. The instruments frequently produced a circular bulge in the canal whilst the buccal and lingual extensions remained unprepared, leaving smear layer and debris.
To evaluate the capability of two hand instrumentation techniques, namely balanced force and circumferential filing, to remove the inner layer of dentine in oval canals.
Thirty mandibular incisors with a single oval canal were selected and divided into two equal groups on the basis of their radiographic bucco-lingual internal diameters measured at a level 5 mm from the apex. Two different hand instrumentation techniques, i.e. balanced force and circumferential filing, were used in each group. A modification of the Bramante muffle mould was used to examine the root canal before and after instrumentation at a level 5 mm from the apex. The two images of the root cross-section before and after instrumentation were superimposed on one another. The perimeter of the canal and the length of the arc where the inner layer of dentine had been removed by the instrumentation were measured by means of an image analysis program. The percentage of this arc was calculated.
The balanced force method removed the inner layer of dentine from 38.6% of the circumference of the canal wall, as opposed to 57.7% using circumferential filing. The difference was not statistically significant (P = 0.101).
In oval canals, both the balanced force and circumferential filing techniques left large portions of the canal wall uninstrumented.
To evaluate surface cleanliness of root canal walls along post space after endodontic treatment using 2 different irrigant regimens, obturation techniques, and post space preparation for adhesive bonding.
Forty teeth, divided into 4 groups, were instrumented, using Ni-Ti rotary files, irrigated with NaOCl or NaOCl+EDTA and obturated with cold lateral condensation (CLC) or warm vertical condensation (WVC) of gutta-percha. After post space preparation, etching, and washing procedure, canal walls were observed using a scanning electron microscope (SEM). Amount of debris, smear layer, sealer/gutta-percha remnants, and visibility of open tubules were rated.
Higher amounts of rough debris, large sealer/gutta-percha remnants, thick smear layer, and no visibility of tubule orifices were recorded in all the groups at apical level of post space. At middle and coronal levels areas of clean dentin, alternating with areas covered by thin smear layer, smaller debris, gutta-percha remnants, and orifices of tubules partially or totally occluded by plugs were frequently observed.
After endodontic treatment, obturation, and post space preparation SEM analysis of canal walls along post space shows large areas (covered by smear layer, debris, and sealer/gutta-percha remnants) not available for adhesive bonding and resin cementation of fiber posts.
To compare in vitro the cleanliness of root canal walls in oval-shaped root canals following automated or manual instrumentation.
Forty-five oval-shaped single-rooted maxillary and mandibular premolars with straight canals were divided into three groups of 15. Automated canal preparation was performed using Anatomic Endodontic Technology (AET, group 1) and the ProFile system (group 2). Manual instrumentation (group 3) was performed with K-Flexofiles. Irrigation was performed using alternately 5.25% NaOCl and 17% EDTA, followed by rinsing with saline. The roots were split longitudinally into halves and the canals examined at x200 and x400 in a scanning electron microscope. The presence of debris and smear layer was recorded at distances of 1, 5 and 10 mm from the working length using a three-step scoring scale and a 300 mum square grid. Mean scores for debris and smear layer were calculated and statistically analysed for significance (P < 0.05) between and within groups, using the Kruskal-Wallis nonparametric anova and Dunn's tests.
At 1, 5 and 10-mm levels the root canals prepared with AET had significantly less surface debris and smear layer on the canal walls compared with canals prepared with ProFile or manual instrumentation. For all three groups significantly lower mean smear layer scores (P < 0.05) were recorded at 5 and 10-mm levels compared with the 1 mm level. Significantly lower mean debris scores (P < 0.05) were also recorded at 5 and 10-mm levels for the AET group whereas no significant differences were found between the three levels for the ProFile and manual instrumentation groups.
Although better instrumentation scores were obtained in canals prepared with AET, complete cleanliness was not achieved by any of the techniques and instruments investigated.
The objective of this in vitro study was to set up a testing protocol and utilize it to evaluate and compare the cutting efficiency of ultrasonic units. Evaluation of two ultrasonic units utilizing two different tips was done by measuring the weght of a dentin specimen before and after ultrasonic treatment for set time periods. The difference in weight was the amount of dentin removed. The ultrasonic units tested were the P5 Booster (Staelec, France) and the Spartan (Obtura-Spartan, Fenton, MO) machines. The tips tested were the CPR-2D and ETD20 types. The units were tested at maximum and medium power. All the experimental variables, ultrasonic unit type, power setting and tip type were found to have an effect on the cutting efficiency (P<0.0001). The P5 ultrasonic unit was more effective at dentin removal than the Spantan ultrasonic unit at both power settings. The ETD-20 tip was more effective at dentin removal than the CPR-2D tip on both units at both power settings.
The aim of this study was to evaluate the effect of ultrasonic treatment on occlusion of dentine tubules in root canal walls after post space preparation in endodontically treated teeth. Twenty-four premolars were instrumented and filled using warm vertical condensation; after post space preparation, they were divided into two groups. The control group was treated using the etching procedure. The experiment samples were treated with EDTA irrigation and ultrasound activation for 30 s before the etching procedure. The roots were divided and the canal walls were examined under SEM at 1000x magnification. The debris and open tubule marks were observed at 2, 6, and 10 mm levels using a three-step scale and the differences in marks among the groups were tested for statistical significance. The following were observed: (a) A decrease in debris and open tubule marks in the samples treated with ultrasounds and the control group (p < 0.05), (b) no significant differences between the three levels of post space in debris and open tubule marks in the experiment samples, and (c) significant differences between the apical and coronal levels in debris and open tubule marks in the control group.
To compare the efficacy of hand versus automated instrumentation when retreating oval-shaped root canals.
Sixty human premolars with single oval canals were instrumented and filled with gutta-percha and sealer and divided into three groups (n = 20)--group 1: ProFile .04 taper rotary instruments; group 2: Anatomic Endodontic Technology (AET), and group 3: manual instrumentation with Hedström files. The teeth were split longitudinally and gutta-percha/sealer remnants in the coronal, middle and apical thirds were assessed with light microscopy. The mean percentage of gutta-percha/sealer remnants for each group was calculated and statistically analysed for significance using an ANOVA repeated measures (P < 0.001) and Tukey's multiple comparison test. The time required for retreatment was analysed using a one-way ANOVA and Tukey's test (P < 0.001).
Overall, 10-18% of the canal walls were covered with gutta-percha/sealer remnants after preparation using any technique. Statistical analysis demonstrated that the mean values for remnants of filling material in the ProFile group were significantly higher than for the other groups (P < 0.001), except in the apical third where no significant difference occurred. In all groups, the mean values in the middle third were higher than the coronal and apical thirds. The retreatment time for ProFile and AET was significantly shorter compared to manual instrumentation with Hedström files (P < 0.001).
Under the experimental conditions, AET instruments and manual instrumentation with Hedström files resulted in cleaner canals. However, completely clean root canal walls were not produced with any of the techniques investigated.
One of the recent trends in endodontics has been the development of bonded obturating materials, in an effort to provide a more effective seal coronally and apically. Materials utilizing dentin adhesive technology have been borrowed from restorative dentistry and adapted to obturating materials. This review discusses the obstacles to effective bonding in the root canal system, the progress that has been made, and possible strategies for improved materials in the future. Much of the literature reviewed and many of the principles discussed are taken from the restorative dentistry literature and applied to the unique environment of the root canal system.
This study evaluated the time, occurrence of fracture, and quality of apical cavity preparation with three different ultrasonic diamond tips: Satelec, Trinity, and a new type, CVD (chemical vapor deposition), using scanning electron microscopy (SEM) analysis. Thirty human single-rooted premolars were selected, submitted to apicectomy, and prepared with ultrasonic tips; impressions were then obtained. The presence of fractures was evaluated on the impressions, and the quality of preparation was evaluated by SEM analysis of teeth and scoring by two examiners. The group prepared with the CVD tips exhibited the shorter preparation time and did not present fractures. There was no statistically significant difference in the quality of preparation for the three tips. The three brands of ultrasonic tips produced adequate grinding without altering the morphology of the apical foramen.
The purpose of this study was to undertake a comprehensive literature review of the root and root canal morphology of the mandibular first premolar. Published studies citing the anatomy and morphology of mandibular premolars report data for over 6,700 teeth. These studies were divided into anatomical studies reporting number of roots, number of canals, and apical morphology. Variations because of sex and ethnic background have also been reported, along with case reports of anomalies. Approximately 98% of the teeth in these studies were single-rooted. The incidence of two roots was 1.8%. Three roots when reported were found in 0.2% of the teeth studied. Four roots were rare and were found in less than 0.1% of the teeth studied. Studies of the internal canal morphology revealed that a single canal was present in 75.8% of the teeth. Two or more canals were found in 24.2% of the teeth studied. A single apical foramen was found in 78.9% of the teeth, whereas 21.1% had two or more apical foramina. The role of genetics and racial variation may result in differences of incidence of root number and canal number in human populations. The dental literature is not unique in studying ethnicity and sex variations. Higher incidences of teeth with additional canals and roots have been reported in Chinese, Australian, and sub-Sahara African populations. Physical anthropology studies seem to show the lowest incidence in Western Eurasian, Japanese and American Arctic populations. The root and root canal morphology of this tooth can be complex and requires careful evaluation prior to root canal therapy.
To comparatively evaluate the preparation of oval root canals with a rotary or an oscillating system.
The middle and coronal parts of 55 extracted permanent teeth with oval canals were prepared using FlexMaster (FM) rotary NiTi instruments and EndoEze AET (EE) stainless steel oscillating instruments. Pre- and postoperative images of cross-sections were superimposed to identify shifts in the center and to assess the percentage of untreated regions. In addition, the middle segment was investigated by scanning electron microscope (SEM) to determine debris and smear layer removal.
The systems did not significantly differ in the shifts of the canal centers in the middle part of the root. Only a few of the preparations yielded an excellent result with no uninstrumented canal wall left. The SEM investigation demonstrated poor results for both systems regarding debris and smear layer removal, but no significant differences could be observed.
Neither FM nor EE was capable of completely preparing oval root canals.
The objective was to review thoroughly the literature of the root and root canal morphology of the human mandibular second premolar and compare the results with the mandibular first premolar. Published studies cite the anatomy and morphology of the mandibular second premolar tooth for more than 7700 teeth. These studies were divided into anatomic studies reporting the number of roots, number of canals, and apical anatomy. Differences caused by gender and ethnicity have also been reported. Individual case reports of anomalies were included to demonstrate the extreme range of variation. Almost all of the teeth in the anatomic studies were single-rooted (99.6%). The incidence of 2 roots (0.3%) and 3 roots (0.1%) was extremely rare. Anatomic studies of the internal canal morphology found that a single canal was present in 91.0% of the teeth. A single apical foramen was found in 91.8% of the teeth. The incidence of more than 1 root (0.4%), more than 1 canal system (9.9%), and more than 1 foramen (8.2%) is lower than that of the mandibular first premolar tooth (2.0%, 24.2%, and 21.1%, respectively). However, the root and root canal morphology of the mandibular second premolar can be extremely complex and requires careful assessment.
To compare the sealing ability and the canal-filled area (gutta-percha + sealer) of three current filling techniques in oval-shaped canals.
A total of 50 oval-shaped root canals were prepared and root filled as follows: G1: lateral condensation (n = 10), G2: System B (n = 10) and G3: Thermafil system (n = 10). All teeth were mounted in a two-chamber apparatus and the coronal access was exposed to human saliva. The appearance of turbidity in the BHI broth over a 15-week period was observed. A cross section of each tooth was made 5 mm from the apex and the samples were prepared for microscopic analysis. Digital image measurements of the cross-sectional area and the area filled by gutta-percha and sealer were performed. Log-rank and Fisher's exact tests were used to analyse the leakage data. Student's t-test was used to analyse the filled-area data.
Overall, 30% of the specimens of G1 and G2 and 20% of G3 demonstrated leakage after 15 weeks and no significant difference was found amongst the groups (P > 0.05). The percentage of canal-filled area was 68, 70 and 78%, respectively (P > 0.05). The correlation analysis revealed no significant relation between the pattern of bacterial leakage and canal-filled area (P = 0.128).
No significant difference in apical sealing and canal-filled area in oval-shaped canals was seen between the three filling techniques. No significant correlation was found between the quality of the apical seal and the filled-area of the root canal space.
This study compared the effect of two drills and five cleaning regimens on post space debridement. One hundred extracted premolars were instrumented and obturated with warm vertical compaction of gutta percha. The teeth were divided into two groups according to the drill used to remove gutta percha/sealer and for post space preparation: a Largo drill (Largo; Dentsply, St Quentin en Yvelines, France) or a MTwo-PF drill (Sweden&Martina, Due Carrare, Padova, Italy). The following cleaning regimens were used: EDTA, ultrasonics, ultrasonics + EDTA, phosphoric acid, and distilled water. Scanning electron microscopic images of the post spaces were taken, and the presence of debris and of open dentin tubules were evaluated. The ultrasonics + EDTA, phosphoric acid, and EDTA groups were comparable in open tubules scores for both drills and in debris scores after the use of MTwo-PF (p > 0.05). The ultrasonics and control groups performed significantly worse (p < 0.05). The MTwo-PF drill resulted as effective as the Largo drill in obtaining a good post space cleaning, especially when followed by ultrasonics + EDTA irrigant regimen.
Surface debris of canal walls after post space preparation in endodontically treated teeth: a scanning electron microscopic study
- Serafino