Assessment of different gutta-percha brands during the filling of simulated lateral canals

AIM: To compare the ability of five different commercially available gutta-percha points to fill simulated lateral canals when subjected to warm vertical compaction. METHODOLOGY: Fifty clear plastic teeth with a lateral canal in each third of the root were used. All teeth were filled using warm vertical compaction. Backfilling was completed with a sealer and the same gutta-percha point used during the apical condensation. After this, they were horizontally sectioned using a diamond disc adapted to a low-speed saw. The resulting sections were embedded in epoxy resin. The extent of gutta-percha and sealer filling were measured in each lateral canal using an IMAGE-PRO 4.0 software system. The voids in each canal were measured using the same system. Data were ranked and analysed using the Kruskal-Wallis statistical test. RESULTS: The mean percentage of the three lateral canals filled with gutta-percha and sealer were respectively: Konne (68.23% and 24.50%), Analytic (67.90% and 25.28%), Obtura (63.80% and 29.60%), Tanari (49.42% and 45.86%) and Dentsply (44.60% and 47.05%). There was significantly (P < 0.05) more gutta-percha in the lateral canal filled with Analytic, Obtura and Konne points than with Tanari and Dentsply points. CONCLUSIONS: The brand of gutta-percha cone had an influence on the length of filling within lateral canals. This may be a reflection of the chemical formulation of the gutta-percha points.     

Chemical and X-ray analyses of five brands of dental gutta-percha cone

AIM: To determine the chemical composition of five commercially available nonstandardized gutta-percha points. METHODOLOGY: The organic fraction (gutta-percha polymer and wax/resin) of nonstandardized gutta-percha points (Dentsply, Tanari, Konne, Obtura Spartan and Analytic Endodontics) was separated from the inorganic fraction (ZnO and BaSO4) by dissolution in chloroform. Gutta-percha polymer was precipitated with acetone. Zinc oxide was partially separated from barium sulphate by reaction with HCl. Energy-dispersive X-ray microanalysis and X-ray diffraction were employed to identify the chemical elements and compounds (barium sulphate and zinc oxide). The barium sulphate content was calculated by percentage of sulphur from elemental microanalysis. All analyses were repeated three times. RESULTS: The means and standard deviations of the percentage by weight of gutta-percha in the points were: Dentsply (14.5 +/- 0.70%), Tanari (15.6 +/- 0.66%), Obtura (17.7 +/- 0.35%), Konne (18.9 +/- 0.32%) and Analytic (20.4 +/- 0.40%). The mean and SD of the zinc oxide content were: Dentsply (84.3 +/- 0.50%), Tanari (82.0 +/- 0.72%), Obtura (69.5 +/- 0.21%), Konne (78.0 +/- 0.05%) and Analytic (66.5 +/- 0.50%). CONCLUSIONS: The method was appropriate to quantify gutta-percha and resin/wax components of gutta-percha points, but not barium sulphate and zinc oxide. An alternative procedure to determine barium sulphate and zinc oxide contents has been proposed based on elemental microanalysis of sulphur. Some brands of gutta-percha did not contain barium sulphate.     

Efficacy of three rotary NiTi instruments in removing gutta-percha from root canals

Aim To investigate the ability of three rotary nickel–titanium instruments and hand instrumentation to remove gutta‐percha and sealer. Methodology Sixty freshly extracted human single‐rooted teeth, each with one root canal, were instrumented with K‐files and filled using cold lateral compaction of gutta‐percha and AH Plus (Dentsply Detrey, Konstanz, Germany) sealer. The teeth were randomly divided into four groups of 15 specimens each. Removal of gutta‐percha was performed with the following devices and techniques: ProTaper, R‐Endo, Mtwo and Hedström files. The specimens were rendered transparent and the area of remaining filling material on the root canal wall was measured using a computer image analysis program. Statistical analysis was accomplished by Kruskal–Wallis and Mann–Whitney U‐tests with Bonferroni correction for the analysis of residual root filling material and working time. Results The ProTaper group had less filling material inside the root canals than the other groups, but a significant difference was found between only the ProTaper and Mtwo groups (P < 0.05). The retreatment time for Mtwo and ProTaper was significantly shorter compared with R‐Endo and manual instrumentation with Hedström files (P < 0.001). R‐Endo was significantly faster than manual instrumentation (P < 0.001). Conclusions Under the experimental conditions, ProTaper left significantly less gutta‐percha and sealer than Mtwo instruments. Complete removal of materials did not occur with any of the instrument systems investigated.     

Effectiveness of different gutta-percha techniques when filling experimental internal resorptive cavities

Aim To determine the quality of root fillings in teeth with artificial internal resorptive cavities filled with Thermafil, JS Quick‐Fill, Soft Core, System B and Microseal, and by cold lateral compaction (LC) technique. Methodology Sixty maxillary incisor teeth were selected. After access cavity preparation and root canal instrumentation, the roots were sectioned horizontally and artificial internal resorption cavities were prepared on the canal walls. The tooth sections were cemented together and the root canals were filled using one of six different techniques: Thermafil, JS Quick‐Fill, Soft Core, System B and Microseal, and by LC. The roots were then divided at the level of the previous section and each root surface was photographed. Image analysis program was used to calculate the percentage of sealer, gutta‐percha and void in the internal resorptive cavities. All measurements were analysed statistically using One‐way anova and Newman–Keuls tests. Results The Microseal technique filled 99% of the artificial resorptive area followed by LC (92%), SystemB (89%), Quick‐Fill (88%), Thermafil (74%) and Soft‐Core (73%). Warm gutta‐percha compaction techniques filled the resorption areas with more gutta‐percha than sealer (Microseal 68%, System B 62%) compared to the other techniques (LC 48%, Quick Fill 41%, Soft Core 34%, Thermafil 35%). In addition, core techniques left a considerable volume of voids in the resorptive areas (Quick‐Fill 12%, Thermafil 26%, Soft Core 27%). Conclusions Warm gutta techniques filled artificial resorption cavities significantly better than the other gutta‐percha techniques.     

In vitro evaluation of apical microleakage following canal filling with a coated carrier system compared with lateral and thermomechanical Gutta-Percha condensation techniques

Aim The apical sealing ability of a coated carrier system was evaluated in extracted human teeth and compared with lateral and thermomechanical condensation techniques using dye penetration. Methodology Sixty‐four extracted single‐rooted teeth were instrumented to an apical size 30 using 4% taper Hero 642? instruments (Micromega, Besançon, France). The sample was divided into three experimental groups. Twenty teeth were randomly obturated with lateral condensation, 20 with thermomechanical compaction and 20 teeth with the Herofill? Soft‐Core system. Four teeth were used as positive and negative controls. The teeth were covered with nail varnish up to 2 mm from the apical foramen and immersed in a 2% aqueous methylene blue dye solution for 1 week and then washed, dehydrated and embedded in resin. The apical 1 mm of each tooth was removed to reveal the apical limit of the preparation. Transverse sections of the teeth were taken at 500, 1000 and 1500 µm from this point and evaluated for apical leakage. Significant differences between the preparations were analysed with a semiautomatic analyser and the ratio of the dye‐penetrated surface to the total dentinal surface was calculated. Results Statistical analysis of the results demonstrated significantly less leakage for the Herofill? Soft‐Core system compared to lateral condensation in terms of total mean dentinal surface and at the 500 µm level. No other differences were noted between Herofill? Soft‐Core and thermomechanical or lateral condensation, either for the total mean value or at each level. Conclusions The Herofill? Soft‐Core system was a reliable obturation system in the apical portion and compared favourably with other gutta‐percha filling techniques.     

Effect of different rotary instrumentation techniques and thermoplastic filling on apical sealing

The aim of this study was to evaluate apical sealing after root canal treatment using two different rotary instrumentation techniques and two thermoplastic root canal filling techniques. The study was performed in 115 human extracted mandibular premolars. After coronary access the apical foramen was opened with a # 15 K file 1 mm beyond the apex. Cleaning and shaping was subsequently carried out at the working length, 1 mm from the apex, with ProFile .04/.06 system (Dentsply/Maillefer), Quantec (Analytic Endodontics/Kerr) or by the step-back technique with 1% sodium hypochlorite solution as irrigating solution. The root canals were filled with Thermafil (Dentsply/Maillefer) or Microseal (Analytic Endodontics/Kerr) or by lateral condensation technique using AH Plus sealer (epoxy type). The teeth were immersed in 2% methylene blue under vacuum. Then, they were longitudinally sectioned. The results showed that the association of Profile and Thermafil Plus provide the best results (p<0.05). In conclusion, the association of different rotary instrumentation techniques and different filling systems influenced the apical sealing.     

Comparison of the fracture resistance of simulated immature permanent teeth using various canal filling materials and fiber posts

Abstract – Background: The purpose of this study was to compare the fracture resistances of immature teeth treated with MTA along with root canal obturation methods using AH Plus, MetaSEAL, MTA Fillapex sealers + lateral compaction technique, and Unicore quartz fiber posts. Materials and methods: Fifty single‐rooted maxillary anterior teeth were divided into five groups. The crowns were dissected and root canals were enlarged. #6 Peeso reamers were allowed to protrude 1 mm. beyond the apex to simulate immature teeth. The apical 4–5 mm of each tooth was filled using Angelus white MTA. The remaining portions of canals were obturated as follows: Group 1: No backfilling (control), Group 2: AH Plus + gutta‐percha, lateral compaction, Group 3: MetaSEAL + gutta‐percha, lateral compaction, Group 4: MTA Fillapex + gutta‐percha, lateral compaction, Group 5: UniCore Fiber posts luted using PermaFlo DC. The specimens were embedded into self‐curing acrylic poured into identical cylinders which were mounted on a jig providing a 45° angle. A compressive load increasing at 1 mm min^?1 was applied and the maximum load at which fracture occurred was recorded. Statistical analysis was performed using Kruskal–Wallis and Dunn’s multiple tests. Results: The highest fracture resistance was obtained with Group 5 (Fiber posts) whereas Group 4 (MTA Fillapex) yielded the lowest values. The mean fracture resistance value of Group 2 (AH Plus) was significantly higher than Group 4 (MTA Fillapex) (P = 0.001). The mean fracture value of Group 5 (Fiber posts) was significantly higher than Group 2 (AH Plus), Group 3 (MetaSEAL), and Group 4 (MTA Fillapex) (P = 0.02, 0.004, and 0.0001, respectively). Conclusion: Within the limitations of this study, UniCore quartz fiber posts provided the highest resistance. This methodology may specifically be advantageous for teeth with arrest of development at early stages, as these teeth are more susceptible to fracture owing to their excessively weak dentinal walls.     

Effectiveness of two nickel-titanium rotary instruments and a hand file for removing gutta-percha in severely curved root canals during retreatment: an ex vivo study

Aim To evaluate ex vivo the effectiveness of hand files, ProTaper and R‐Endo rotary instruments when removing gutta‐percha from curved root canals. Methodology Ninety severely curved teeth were divided into three groups. The root canals were accessed, prepared and filled with vertically condensed gutta‐percha and sealer. Removal of gutta‐percha was performed with the following devices and techniques: Hedström files (Vereinigte Dentalwerke, Munich, Germany), ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) and R‐Endo (Micro‐Mega, Besançon, France). All techniques were used with the solvent eucalyptol. The amount of filling material debris remaining on root canal walls was assessed radiographically from two directions: mesio‐distal and bucco‐lingual. The images were digitized and analysed with autocad 2000 software. Total canal area, area of the cervical, middle and apical thirds, and area of remaining filling material from both directions were outlined by two different operators and calculated. Statistical analysis of remaining filling material within each third of the canals was performed by the Kruskal–Wallis test. Results Comparisons of the percentages of remaining filling material in the entire canal did not reveal any significant differences between the methods of removal. However, the canal third was of relevance in all groups; the apical third had the most remaining filling material compared with the middle and cervical thirds (P = 0.0012). Conclusion All instruments left filling material inside the root canal. ProTaper and R‐Endo rotary instruments were inadequate for the complete removal of filling material from the root canal system.     

A comparison of the efficacy of conventional and new retreatment instruments to remove gutta‐percha in curved root canals: an ex vivo study

Aim To compare the efficacy of conventional and new retreatment instruments when removing gutta‐percha root fillings in curved root canals. Methodology A total of 56 curved molar roots were instrumented with ProFile instruments and filled using system B and Obtura II. The root fillings were removed with manual K‐files and Hedström files (Dentsply Maillefer), ProFile (Dentsply Maillefer), R‐Endo (Micro–Mega) or ProTaper Universal retreatment files (Dentsply Maillefer). Eucalyptol was used as a solvent with all techniques. Bucco‐lingual and proximal radiographs of the roots were exposed and the percentage area of the remaining material was calculated by dividing the area of remaining filling material by the area of canal wall. Data were statistically analysed with Kruskal–Wallis and Mann–Whitney U tests (P = 0.05). Results None of the techniques completely removed the root filling materials. No significant differences were found amongst the coronal, middle and apical thirds in both radiographic projections (P > 0.05). In the bucco‐lingual direction, the remaining filling material was significantly less following manual instrumentation than R‐Endo and ProTaper instrumentation (P < 0.05). In the proximal view, it was significantly less following manual and ProFile instrumentation than R‐Endo (P < 0.05). Complete removal of filling material occurred only in three specimens (with manual instruments). Manual instruments were significantly faster than R‐Endo and ProFile (P < 0.05). More procedural errors (five fractured instruments and two perforation) were noted when using ProTaper (P < 0.05). Conclusions In this laboratory study in curved molar roots, ProTaper Retreatment and R‐Endo instruments were less effective in removing filling material from canal walls than manual and ProFile instruments.     

In vitro comparison of different reciprocating systems used during endodontic retreatment

The present study evaluated the effectiveness of two reciprocating systems for the removal of root‐filling material during endodontic retreatment. One hundred extracted mandibular premolars were prepared and root‐filled with gutta‐percha and sealer. Root fillings were removed with K‐files according to the following techniques: Group A – hand instrumentation; Group B – Endo‐Gripper system driven by compressed air; Group C – INTRAmatic 29CH + INTRA‐LUX 3LD driven by compressed air; Group D – Endo‐Gripper system driven by electric engine; Group E – INTRAmatic 29CH + INTRA‐LUX 3LD driven by electric engine. The amount of filling debris on root canal walls was assessed radiographically and analysed using Auto CAD 2000 software. One‐way anova and Duncan’s test revealed statistically significant differences only in the middle third (P = 0.01); the best results being reached in group D. The apical third displayed the greatest amount of filling material debris, regardless of the technique used.     

Leakage along warm gutta-percha fillings in the apical canals of curved roots

Abstract – The aim of this study was to investigate the leakage along the apical portion of warm gutta‐percha obturated curved canals. Human mandibular premolars with single, curved (21°–40°) canals were prepared using the Lightspeed technique. Two groups of prepared canals, matched according to curvature and prevalence of apical transportation, were obturated by two techniques. Coronal gutta‐percha was removed immediately after root obturation was completed to simulate the procedure for post space preparation. Leakage along the apical 3 mm of root filling was measured with a fluid transport device. Vertical condensation of warm gutta‐percha and Pulp Canal Sealer provided less leakage than Thermafil plastic obturators and AH26 sealer (P=0.002).     

Effect of customization of master gutta-percha cone on apical control of obturation using different techniques: an in vitro study

Aims (i) To compare the prevalence of root filling extrusion placed using three different obturation techniques, each with or without customization of the master gutta‐percha cone; and (ii) to investigate the effects of various factors on the prevalence of root filling extrusion. Methodology A total of 180 roots were selected and randomly allocated into three groups. Five general dental practitioners were recruited; each obturated one group of the roots using three techniques, namely cold lateral condensation (n = 20), Schilder's warm vertical condensation (n = 20) or continuous wave condensation (n = 20). Each technique was completed with (n = 10) or without (n = 10) customization of the master gutta‐percha cone using chloroform. Two groups of the roots were recycled to allow all five operators to use them. Two observers examined the preinstrumentation, working length, master apical file and postobturation radiographs, and determined the presence of root filling extrusion and voids independently; they were blinded regarding the obturation technique used. The presence of root filling extrusion was also assessed by inspecting the root apex after obturation. The data were analysed using logistic regression models. Results A total of 300 root fillings were performed and 291 were included for analysis. Most of the root fillings were placed within 0.5 mm of the working length (80%, n = 233); only 20% (n = 58) were placed >0.5 mm beyond the working length. The odds of prevalence of extrusion >0.5 mm were significantly reduced by approximately 50% when cold lateral condensation (OR = 0.50; 95% CI = 0.26, 0.99; P = 0.04) or customization of master gutta‐percha cone (OR = 0.55; 95% CI = 0.30, 0.99; P = 0.04) was used. One operator produced 2.5 times more extruded root fillings than the other operators (OR = 2.50; 95% CI = 1.31, 4.78; P = 0.006). Other factors, such as root canal curvature and length, apical size of the prepared canal, as well as the operator's preferred obturation technique, were shown to have no significant influence on the prevalence of extrusion. Conclusions The prevalence of extrusion was significantly lower when cold lateral condensation and customization of the master cone were used. The ‘operator’ emerged as a significant factor affecting the prevalence of root filling extrusion.     

An in vitro comparison of three thermal gutta percha systems

Aim The aim of this study was to compare the ability of three contemporary obturation techniques to resist microleakage, using root canals prepared in extracted single rooted teeth by a standardized method. Methodology The shaping technique involved the use of tapered nickel titanium rotary files to create a uniform 0.08‐mm/mm taper. Six groups were compared, two representing control groups, a third group being obturated with a warm vertical condensation technique, a fourth group by an injection thermoplasticized system, a fifth group with a thermomechanical compaction method and a sixth group using cold lateral condensation. A zinc oxide/eugenol sealer was used as the sealant in all the obturation procedures. Forty‐six extracted teeth were used in the study, three teeth in each control group and 10 teeth in each of the remaining four groups. Microleakage was compared using dye leakage with Indian ink. Penetration of the dye at the gutta percha/dentine interface was visualized after the root had been rendered transparent. Dye leakage was then measured from four aspects with the use of a stereomicroscope and export of a digital image to a software package, to facilitate accurate assessment of dye penetration. Two parameters were measured for each sample, the mean dye penetration and maximum dye penetration. Results The mean values for linear dye leakage in the thermomechanical compaction group was 0.53 mm, the warm vertical condensation group was 0.73 mm, the injection thermoplasticized group was 0.15 mm and the cold lateral condensation group was 0.53 mm. There was no statistical difference between the means of the different groups (P > 0.05). The mean of the maximum values for dye leakage in the thermomechanical compaction group was 0.65 mm, the warm vertical condensation group was 1.02 mm, the injection‐thermoplasticized group was 0.28 mm and the cold lateral condensation group was 0.74 mm. There was no statistical difference between the means of the different groups (P > 0.05). Conclusions Within the conditions of this study, there was no statistical difference between the different groups with respect to either mean or maximum dye leakage.     

Evaluation of fracture resistance in simulated immature teeth using resilon and ribbond as root reinforcements – An in vitro study

Abstract – Background/Aim: To compare the reinforcement and strengthening ability of resilon, gutta‐percha, and ribbond in endodontically treated roots of immature teeth. Material and Methods: Sixty five freshly extracted human maxillary anterior teeth were prepared with a Peeso no. 6 to simulate immature teeth (Cvek’s stage 3 root development). After instrumentation, each root was irrigated with sodium hypochlorite and with ethylene diamino tetra acetic acid to remove the smear layer. To simulate single visit apexification technique a 4–5 mm white Pro Root mineral trioxide aggregate plug was placed apically using schilder carrier. The teeth were divided into three experimental groups and one control group. Group I – control group (root canals instrumented but not filled); Group II – backfilled with thermoplastisized gutta‐percha using AH plus sealer; Group III – reinforced with Resilon using epiphany sealer; Group IV – reinforced with Ribbond fibers using Panavia F luting cement. A Universal Testing Machine was used to apply a load, at the level of the lingual cementoenamel junction with a chisel‐shaped tip The peak load to fracture was recorded and statistical analysis was completed using student’s t‐test. Results: Values of peak load to fracture were 1320.8, 1604.88, 1620, and 1851newtons for Group I to Group IV respectively. The results of student’s t‐test, revealed no significant difference (P > 0.05,) between Group II and Group III. Comparison between Group IV and Group III and between Group IV and Group II revealed highly significant difference (P > 0.001). Conclusions: Teeth reinforced with Ribbond fibers using Panavia F luting cement showed the highest resistance to fracture. Resilon could not strengthen the roots and showed no statistically significant difference when compared with thermopasticised gutta‐percha in reinforcing immature tooth when tested with universal testing machine in an experimental model of immature tooth.     

Brazilian gutta-percha points. Part I: chemical composition and X-ray diffraction analysis

Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP and Dentsply FM) were analysed chemically and by X-ray diffraction, and their chemical compositions were compared. The organic fraction (gutta-percha polymer and wax/resin) of the gutta-percha points was separated from the inorganic fraction (ZnO and BaSO4) by dissolving them in chloroform. The gutta-percha polymer was precipitated with acetone. The inorganic fraction was analysed by elemental microanalysis. Energy-dispersive X-ray microanalysis (EDX) and X-ray diffraction were employed to identify the chemical elements and compounds (barium sulfate and zinc oxide). The barium sulfate content was calculated based on the percentage of sulfur found in the elemental microanalysis. All analyses were repeated three times. The means and standard deviations of the percentage by weight of gutta-percha in the points were: Konne (17.6 +/- 0.30), Tanari (15.2 +/- 0.30), Endopoint (16.7 +/- 0.23), Odous (18.8 +/- 0.20), Dentsply 0.04 (15.7 +/- 0.17), Dentsply 0.06 (16.6 +/- 0.17), Dentsply TP (21.6 +/- 0.15) and Dentsply FM (16.3 +/- 0.23). The means and standard deviations of the zinc oxide content were: Konne (79.9 +/- 0.10), Tanari (81.9 +/- 0.07), Endopoint (81.3 +/- 0.40), Odous (79.7 +/- 0.26), Dentsply 0.04 (77.9 +/- 0.03), Dentsply 0.06 (78.2 +/- 0.07), Dentsply TP (69.8 +/- 0.19) and Dentsply FM (72.6 +/- 0.70). The method utilized was appropriate to quantify gutta-percha, wax/resin, zinc oxide and barium sulfate. Cone brands without barium sulfate were found. An unusual high wax/resin percentage was detected in Dentsply FM (p = 0.0003). Dentsply TP showed the highest gutta-percha percentage.     

不同根管充填技术对椭圆形根管的根尖封闭效果

目的 探讨采用不同根管充填技术对椭圆形根管根尖封闭效果的影响.方法 选取近期拔除的椭圆形单根管前磨牙120颗随机分成6组,每组20颗,采用iRoot-SP和AH-Plus根管封闭剂,结合单尖充填法、连续波热牙胶垂直加压充填法、冷牙胶侧方加压充填法,即单尖iRoot组、热牙胶iRoot组、冷牙胶iRoot组、单尖AH组、热牙胶AH组、冷牙胶AH组,采用染料渗透法观察根尖的微渗漏情况.结果 热牙胶iRoot组、热牙胶AH组的根尖染料渗入深度明显小于单尖iRoot组、单尖AH组(P<0.05);热牙胶iRoot组、冷牙胶iRoot组尖染料渗入深度明显小于热牙胶AH组、冷牙胶AH组(P<0.05);其他的组间两两比较差异均无统计学意义(P>0.05).结论 热牙胶垂直加压技术可以使椭圆形根管达到更好的根尖封闭效果,且配合使用iRoot SP根管封闭剂的封闭效果较配合使用AH-Plus根管封闭剂好.     

The effect of chloroform,orange oil and eucalyptol on root canal transportation in endodontic retreatment

The purpose of the present study was to assess the effect of solvents on root canal transportation in endodontic retreatment. Sixty extracted human permanent mandibular first molars with curved root canals were selected. All of the root canals were prepared using Twisted File Adaptive instruments (SybronEndo, Orange, CA, USA) and filled with gutta‐percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany) using the cold lateral compaction technique. The teeth were assigned to four retreatment groups as follows (n = 15): eucalyptol, chloroform, orange oil and control. The canals were scanned using cone‐beam computed tomography scanning before and after instrumentation. The chloroform group showed a significantly higher mean transportation value than the orange oil and control groups at the 3 and 5 mm levels (P = 0.011 and P = 0.003, respectively). There was no significant difference among the orange oil, eucalyptol and control groups in terms of canal transportation (P > 0.61). The chloroform led to more canal transportation than the eucalyptol and orange oil during endodontic retreatment.     

Utilization of gutta-percha for retrograde root fillings

Abstract – Just as gutta‐percha used with a root canal sealer is a recommended material for orthograde root fillings, it could similarly be the material of choice for retrograde fillings. Unfortunately, clinical accessibility and visibility do not always facilitate such a technique. The aim of this article is to present a new technique which enables retrograde fillings to be achieved with gutta‐percha and a sealer. After the apex had been resected, a hole was drilled perpendicular to the plane of section of the apex about 1 mm coronally. The bucco‐lingual depth required to reach the main canal was calculated. The cavity was then dried, coated with the sealer, and obturated with gutta‐percha in accordance with thermo‐mechanical compaction techniques. After excess filling material had been removed, the gutta‐percha was cold burnished and the angles of the root were smoothed. Clinical cases illustrating healing of the periapical tissues are shown.     

Post space cleaning using a new nickel titanium endodontic drill combined with different cleaning regimens

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.     

Effect of dowel space preparation and composite cement thickness on retention of a prefabricated dowel

PURPOSE: This investigation examined what effect cement thickness had on retention of prefabricated endodontic dowels luted with a composite resin cement (Panavia 21 OP; J Morita, Irvine, CA) into canals previously obturated with gutta percha and a eugenol-based sealer. MATERIALS AND METHODS: Sixty-four single-rooted teeth were decoronated, filed, cleaned, and sequentially shaped with sizes 2-5 Gates Glidden drills (Dentsply/Maillefer, Tulsa, OK) and 0.12 taper rotary instrumentation. Teeth were then divided into 4 groups of 16 specimens each. All specimens were obturated with gutta percha and a eugenol-based sealer. Dowel space preparation and dowel cementation were completed 1 week after obturation. Ten-millimeter-deep dowel spaces were prepared using dowel drills with 4 different diameters: size 5 Parapost drill (Group 1; Coltene/Whaledent, Mahwah, NJ); size 5.5 Parapost drill (Group 2; Coltene/Whaledent); size 6 Gates Glidden drill (Group 3; Dentsply/Maillefer); size 6 Parapost drill (Group 4; Coltene/Whaledent). Size 5 Paraposts were then cemented with Panavia 21 OP. After 48 hours of storage, specimens were mounted in polyvinyl chloride (PVC) pipe with acrylic, and the dowels were removed in tensile mode using a universal testing machine at 1 mm/min, with data recorded in kilograms. RESULTS: (all values in kilograms) Group 1 (Parapost 5) mean = 15.07, 95% confidence interval (CI) = +/-6.11; Group 2 (Parapost 5.5) mean = 25.60, 95% CI = +/-7.39; Group 3 (Gates-Glidden 6) mean = 43.15, 95% CI = +/-7.81; Group 4 (Parapost 6) mean = 37.75, 95% CI = +/-6.35. Analysis of variance and Bonferroni tests revealed that Group 3 had significantly greater mean retention strength values than Group 1 and Group 2 (p <.05), and that Group 4 had significantly greater mean retention strength values than Group 1 (p <.05). CONCLUSIONS: Paraposts cemented with Panavia 21 OP showed significantly greater retention in oversized dowel spaces compared with dowel spaces prepared with the manufacturers' matched dowel-drill set.