Gutta-percha Points Research Articles

Healing Assessment of Osseous Defects after Surgical Removal of Periapical Lesions in the Presence of Hydroxyapatite, Nanohydroxyapatite, and a Combination of Nanohydroxyapatite and Platelet-rich Fibrin: A Clinical Study

Abstract: Aim: to evaluate the bone healing in failed endodontically treated teeth after surgical removal of periapical lesions and placement of hydroxyapatite (HA), nanohydroxyapatite (nHA) and a combination of nanohydroxyapatite with platelet rich fibrin (PRF) periapically. Subjects and methods: the study was conducted on twenty-four patients having periapical radiolucency in single rooted teeth. The selected teeth were divided into three groups: Group A, Group B, and Group C; of 8 teeth each. All the teeth were retreated in two visits. In the first visit the old filling was removed using Protaper retreatment files (Dentsply Sirona®) then irrigation with sodium hypochlorite 2.5% was done. All canals were dried and filled with Di-antibiotic paste (metronidazole and ciprofloxacin). In the second visit the canals were obturated with Pro Taper gutta-percha points and root canal sealer (Adseal resin sealer) followed by surgical intervention in the same day. A periapical curettage along with apicoectomy were established. In all the groups, root end cavity was prepared and filled with MTA (ProRoot MTA; DENTSPLY Tulsa Dental Specialties). In Group A, hydroxyapatite powder was packed in the curetted periapical defect. In Group B, nanohydroxyapatite powder was packed in the curetted periapical defect. In Group C, nanohydroxyapatite with PRF were mixed and packed in the curetted periapical defect. In all groups, patients recall visits were scheduled at 1, 3, and 6 months’ time intervals for clinical and radiological evaluation. Results: after one month; there was a statistically significant difference between the median percentage changes in lesions size in the three groups. Pair-wise comparisons between groups revealed that there was no statistically significant difference between group B (nHA) and group C (PRF and nHA) groups. Both showed statistically significantly higher median percentage reduction in lesions size than group A (HA group). After three as well as six months; there was no statistically significant difference between the median percentage decreases in lesions size in the three groups. Conclusion: It was concluded that nHA combination with PRF produced faster periapical healing (bone regeneration) in the first three months than nHA alone. However, HA produce periapical healing (bone regeneration) after six months.

Comparative Evaluation of Fracture Resistance of Endodontically Treated Bicuspids Instrumented With Hand Files, TruNatomy, ProTaper Next, ProTaper Gold, and WaveOne - An In vitro Study.

Aim:The study aims to compare and evaluate the fracture resistance of endodontically treated bicuspids instrumented with Hand Files, TruNatomy (TRN), ProTaper Next (PTN), ProTaper Gold (PTG), and WaveOne (WO).Materials and Methods:In total, 45 extracted single-rooted human premolar teeth were selected and sectioned at or below the cementoenamel junction to obtain roots 15 mm long. The samples were divided into four experimental groups and one control group (n = 9): instrumentation with nickel–titanium (NiTi) Hand Files (control group), instrumentation with TRN files, instrumentation with PTN files, instrumentation with PTG files, and instrumentation with WO files. The samples were obturated by lateral compaction technique using gutta-percha points and AH Plus sealer. A vertical load was applied to the tooth using the universal testing machine (Tecsol-TSI-BDS-2Kn-Sr No. 170710) for the fracture resistance test. Statistical analysis was performed.Results:The study reported that teeth instrumented with NiTi hand files exhibited the highest fracture resistance when compared to all the rotary and reciprocating file systems. Among rotary and reciprocating instruments, root prepared with TRN files showed the most significant resistance to fracture compared with PTN, PTG, and WO files.Conclusion:Within the limitations of this study, it can be concluded that minimally invasive instrumentation of the system preserves more pericervical dentin, which may increase the resistance to fracture. Results of this study and other studies support the use of minimally tapered instruments to improve the fracture resistance of endodontically treated teeth.

Antibacterial Efficacy of Herbal Solutions in Disinfecting Gutta Percha Cones Against Enterococcus Faecalis.

Objective:Even when endodontic procedures are performed with the utmost care, reinfection can occur. One possible explanation is that contaminated gutta-percha cones were used in the root canals. The study's goal is to assess the antimicrobial activity and efficacy of Neem, Turmeric, and Calotropis Procera in disinfecting gutta percha cones prior to obturation.Materials and Methods:80 Gutta percha (GP) cones were contaminated with 0.5ml Ferlands standard Enterococcus Faecalis for 10 minutes.20 cones each were treated up to 5 minutes in their prepared neem, turmeric, calotropis and sodium hypochlorite solutions. Then, they placed in BHI broth and vertex is done for 1 minute. One loopful of broth was stroked on 20 blood agar plates of 5 each neem, turmeric, calotropis and sodium hypochlorite. The plates were then incubated for 24 hours aerobically at 37°C and the colony forming units were counted with a digital colony counter.Results:Mean colony forming units were compared in all the groups and there was a statistically significant difference present among the groups (p<0.01). Sodium Hypochlorite (NaOCL)as control group showed average of 5 colony forming units(CFU). Turmeric had the least average of 55 CFU and was the most effective of the experimental groups. Neem and Calotropis had the higher average of 130 CFU and 200 CFU respectively, making it the least effective of the solutions tested.Conclusion :All of the herbal solutions tested positive for disinfection of GP points. When compared to Neem and Calotropis, Turmeric was the most effective and has superior antibacterial activity.

Effect of photosensitizers on modulating bond strength of different luting cements used for cementation of resin modified composite fiber posts.

The aim of the study was to evaluate the tensile BS of FPs luted with conventional and self-adhesive resin modified GIC cement on disinfection of post-space radicular dentin with various photo-activated photosensitizer (chitosan, TB and Clp6). Sixty-six orthodontically extracted mandibular pre-molars were selected on specific exclusion/inclusion criteria, trailed by thorough debridement of plaque/calculus and disinfected by immersion in Chloramine T trihydrate solution for 48 hrs. The selected teeth were sectioned from the cement-enamel junction removing the crown. The radicular region of the samples was entrenched perpendicularly in heat cure resin modified acrylic. The pulpal tissue was detached using K-files trailed by canal shaping with ProTaper Next rotary NiTi (Dentsply Sirona, Gloucestershire, UK) files under continuous irrigation with NaOCl. The canals were dried using paper points trailed by obturation by Pro Taper Next Obturators gutta-percha points (Dentsply, UK) coated with ADSEAL (Meta Biomed, Chungcheongbuk-do, South Korea). After incubation for seven days in an environment mimicking oral cavity, post space was created using peso reamers. The space was disinfected by G1: chitosan 3 mg/mL; G2: 13-15 mg/mL TB and G3: Clp6. After photo-irridation the FPs were luted with conventional (n=11) and resin modified self-adhesive cement (n=11) for each group respectively. The specimens were incubated for 48 hrs prior to tensile BS testing. The type of bond fracture/failure was evaluated under 30x magnification. The tensile BS was statistically analyzed using ANOVA trailed by Tukey's test to respective groups. FPs luted using self-adhesive resin modified cement with prior to disinfection by TBs displayed highest tensile BS 291.47 N ± 5.36. On the contrary, post-space disinfected by Clp6 displayed statistically significant (p ≤ 0.05) lowest bond strength (276.62 N ± 4.31). Intra-group analysis displayed statistically significant difference in bond strength of the luting dental materials (p ≤ 0.05). The self-adhesive resin modified cement revealed utmost bond strength on pre-treatment of post-space with respective photo-activated photosensitizer (chitosan, TB & Clp6) in contrast to conventional GIC.

Impact of endodontic access cavity design and thermo-cycling on fracture strength of root canal treated mandibular molar teeth

Aim: Aim of study is to evaluate the fracture resistance of the root canal treated Mandibular 1st and 2nd molar teeth with Conventional(TEC) access design and Truss(TREC) access design restored with composite resin and subjected to thermocycling. Method: 60 human 1st and 2nd molar (mandibular) teeth were randomly categorised into six (6) groups: CON (GroupI), TEC (GroupIII), TREC(GroupV) not subjected to thermocycling whereas CONTC (GroupII),TECTC(GroupIV) and TRECTC(GroupVI) subjected to thermocycling. Biomechanical preparation of the canals were done upto #F3 of Protaper gold rotary files (Dentsply) and obturated using gutta-percha points and restored using SDR bulk-fill composite(Dentsply). All samples were then subjected to thermo-cycling for 5000cycles between 15°C and 45°C for different time intervals and their fracture toughness tested under an Universal Tester with steel ball of diameter 5mm at a constant 1mm/min speed. Two-way and one-way ANOVA test employed for statistical analysis. Result: The fracture strength of teeth in TREC group had no notable variation with the control group (P&gt;0.05) without thermocycling. Both TEC and TREC designs notably reduced the fracture toughness after thermocycling (P&lt;0.05). The least fracture resistance was noted in TECTC group. Conclusion: TREC ought to increase the fracture resistance of root canal treated teeth after thermocycling.

The outcome of endodontic treatment using an enhanced infection protocol in specialist practice.

Objectives This study aims to determine the outcome of primary root canal treatment with specific enhanced infection control protocol. The secondary aim was to compare percentages of successful outcomes in this study with a previous study undertaken by the same operator using both periapical radiograph (PR) and cone beam computed tomography (CBCT).Materials and methods Root canal treatment of 110 teeth in 95 patients carried out by a single operator using an enhanced infection control procedure (disinfection of gutta percha before obturation, changing of gloves after each intraoperative radiograph and also before the start of the root canal obturation). PR and CBCT scans of 94 teeth in 87 patients were assessed 12 months after completion of primary root canal treatment and compared with their respective pre-treatment (diagnostic) PR and CBCT scans. Healing was assessed by a consensus panel consisting of two calibrated examiners. Comparison of the PR and CBCT images for 'healed' and/or 'healing' outcomes was performed using McNemar's test.Results The 'healed' rate (absence of periapical radiolucency) was 89.4% using PR and 78.7% for CBCT (p <0.046). This rate increased to 95.7% for PR and 92.6% for CBCT when the 'healing' group (reduced size of periapical radiolucency) was included (p <0.046).Conclusion The frequent changing of gloves during the course of endodontic treatment and disinfection of gutta percha points before obturation, together with the use of contemporary rotary files, resulted in a high success rate of primary root canal treatment compared to similar clinical studies conducted previously.

Micro-CT assessment of gap-containing areas along the gutta-percha-sealer interface in oval-shaped canals.

To assess the interfacial adaptation (gap-containing areas) of two root canal sealers (EndoSequence BC Sealer and AH Plus) to a conventional gutta-percha (GP) cone (GP-sealer interface) in oval-shaped canals filled using the single cone technique. Sixteen teeth with oval-shaped canals were selected, scanned in a micro-computed tomographic device, and pair-matched according to the volume, aspect ratio and configuration of root canals. Root canals were then sequentially prepared with WaveOne Gold Primary and Large instruments, followed by filling with WaveOne Large GP points associated with either the premixed calcium-silicate EndoSequence BC Sealer or the epoxy resin-based AH Plus sealer (n=8 per group) using the single cone technique. After 7days stored in phosphate-buffered saline solution at 37°C, the specimens were rescanned and the reconstructed images segmented in order to differentiate the filling materials (sealer and GP cone) to the dentine. A total of 453 cross-sectional slices were assessed and categorized according to the presence or absence of gaps at the GP-sealer interface. Mann-Whitney U-test verified the differences between groups and were considered significant at alpha=5%. Gaps were non-homogenously distributed in two-dimensional axial cross-section images and none of the specimens showed completely gap-free areas along the entire GP-sealer interface. Root canals filled with EndoSequence BC Sealer and AH Plus displayed 171 (37.75%) and 136 (30.02%) slices with gaps in the GP-sealer interface and these frequencies were statistically significant (p=.000). Although none of the specimens had a gap-free area along the entire GP-sealer interface, oval canals filled with AH Plus showed less gaps than the ones filled with EndoSequence BC Sealer.

Efficiency Evaluation of Various Solvents in Retreatment of Endodontic Filling in Extracted Teeth.

ObjectivesThe aim of this study was to evaluate the retreatment duration and efficacy of eucalyptol and tea tree oil in engine driven and manual retreatment of epoxy resin based endodontic filling in extracted human teeth.Methods and materialsSixty human single rooted teeth were randomly divided into two groups. The first group was prepared using hand files, and the second one using Reciproc system. Root canals were filled with gutta-percha points and AH Plus sealer. Retreatment was performed using K-reamers and Hedström files for the first group, and Reciproc instruments for the second group. Each group was divided into two subgroups (n=15) according to the retreatment solvent used (eucalyptol or tea tree oil). Root canals were longitudinaly split and analized with stereomicroscope (15x magnification). The surface of the remaining filling material was measured using an image processing software.ResultsThere were no statistically significant differences in the area of residual filling material among used solvents, nor in applied technique. Retreatment with Reciproc instruments was significantly faster compared to retreatment using hand files. The manual retreatment technique was faster when tea tree essential oil was used as a solvent compared to eucalyptol.ConclusionsAustralian tea tree oil and eucalyptus oil were equally effective in removing endodontic filling material, but none of canals were completely free of the residual filling material. Retreatment with Reciproc instruments was faster compared to retreatment using hand files. The manual retreatment technique is faster when tea tree essential oil is used as a solvent compared to eucalyptol.

Apical Sealing Ability of Experimental Apatite Calcium Phosphate based Coated Gutta-percha Points

Aims: This study aimed to assess the apical sealing ability of experimental apatite-coated gutta-percha points compared to various coated gutta-percha root filling materials.&#x0D; Study Design: Experimental in-vitro study.&#x0D; Place and Duration of Study: Department of Restorative Dentistry, University of Malaya, June 2014 and November 2014.&#x0D; Methodology: Ninety-six extracted permanent maxillary central incisors were standardized and prepared by ProTaper universal rotary files. The specimens were allocated into six groups (n=15) and filled using matching single cone technique as follows; EndoREZ points with EndoREZ sealer, Bioceramic coated points (BCGP), Active GP (ActiV GP), Conventional gutta-percha (GP), apatite coated GP (HAGP) all in combination with Endosequence BC sealer. The sixth group was filled using cold lateral compaction of Conventional GP and Endosequence BC sealer. The specimens were subjected to a dye leakage test. The remaining six teeth were divided equally to be used as a negative and positive control. One-way analysis of variance (ANOVA) followed by the post hoc Dunnett T3 test was performed for data analysis, and the significance value was set at P =.05.&#x0D; Results: ActiV GP had the least leakage followed by BCGP, HAGP, cold lateral compaction, conventional GP, and EndoRez.&#x0D; Conclusion: HAGP as root canal filling showed favourable sealing ability comparable to ActiV GP, BCGP, and conventional GP and it was superior to EndoREZ.

Evaluation of in vitro experimental model for analysis of bioceramic sealers

This study aimed to evaluate physicochemical properties of three ready-to-use calcium silicate-based endodontic sealers: Endosequence BC Sealer, Bio C Sealer, and Sealer Plus BC. Radiopacity was evaluated using specimens of 10 mm in diameter and 1 mm in height, along with an aluminum step wedge. For the flow test, 0.5 mL of each sealer was deposited between glass plates and the mean of the measurement of two diameters was considered the cement flow value. For pH and calcium release, root canals of 30 prototypes of upper incisor acrylic resin teeth were filled with sealer and gutta percha point and then immersed in containers with 13 mL of ultrapure water. Both pH and release of calcium ions (atomic absorption spectrophotometer) were measured at 3, 24, 72, and 168 h. Acrylic resin teeth were scanned by Micro-CT 1174 at the time of pH and calcium ion readings for volumetric change analysis. The data were analyzed by ANOVA, Tukey’s, Kruskal-Wallis, and Dunn’s tests. Endosequence BC Sealer presented the lowest, and Bio C Sealer the highest volumetric change after 72 h and 168 h (p < 0.05). Endosequence BC Sealer presented higher radiopacity (p < 0.05). All materials showed alkalinization capacity. All of them presented calcium ion release, with a higher value for Sealer Plus BC. All materials presented alkalinization, calcium release capacity, radiopacity, and flow above the minimum values required by the ISO standard. The highest volumetric loss was experienced by Bio C Sealer and the lowest one by Endosequence BC Sealer.

Endodontic treatment during pregnancy: case series and literature review

ABSTRACT The aim of this paper is to provide a scientific basis for conducting safe root canal treatment in pregnant women, illustrating with case reports treated in the extension project Maternal-Child Dental Care at the Federal University of Pelotas. The scientific bases address the main doubts of professionals when performing prenatal dental care: use of radiographic examination, local anesthetics, prescription of medications, among other essential factors in the care of pregnant women. The assisted pregnant women sought care with dental pain. In two cases symptomatic irreversible pulpitis was diagnosed, while a third was experiencing acute apical periodontitis. Endodontic procedures were performed under controlled and standardized conditions. The root canals were prepared in a single session, using mechanical instrumentation with reciprocating kinematics (Wave One® Gold Primary - Dentsply Sirona), and the root canal length was determined by an electronic apex locator FinePex (Schuster). Root canal filling was performed by the single cone technique with Wave One® gutta-percha points. After endodontic treatment, coronal sealing was performed with composite resin A2 Z350 XT (3M ESPE). The care related to the gestational condition is highlighted, and the patients remain under monitoring. It is concluded that the use of apical locators and mechanical instrumentation, using reciprocating files associated with the single cone obturation technique with a standardized cone for each system, represents advances for the accomplishment of endodontic treatment in pregnant patients due to the shorter clinical time and greater comfort of the procedure.

XP Endo Finisher-R and PUI as supplementary methods to remove root filling materials from curved canals.

This study assessed the ability of XP-endo Finisher R (FKG, La Chaux-de-Fonds, Switzerland) to remove filling remnants from curved mesiobuccal canals of maxillary molars, using the passive ultrasonic irrigation (PUI) technique as a comparison. Twenty-four curved main mesiobuccal canals (MB1) of maxillary molars were instrumented with Wave One (#25/07) and filled with gutta-percha points and AH Plus Sealer. Samples were then re-treated with a standardized protocol with Wave One (#35/06) as the master apical file. Micro-CT scans measured baseline volume of remaining filling material (in mm3). Samples were divided into two groups (n = 12) according to the supplementary cleaning approach: (PUI) or XP-endo Finisher R. Statistics compared baseline and final volume of filling material (within-group); and the percentage of filling material reduction (between-group). Mean baseline volumes, final volumes, and percentages of reduction (%) of filling material for XP-endo Finisher R and PUI were respectively: 0.060 mm3, 0.042 mm3, and 31.28%; and 0.064 mm3, 0.054 mm3, and 16.57%. Both tested protocols reduced the amount of filling material (p < 0.05). XP-endo Finisher R had higher percentage of reduction as compared to PUI (p < 0.05). XP-endo Finisher R and PUI used as supplementary cleaning protocols during re-treatment improved the removal of root filling material in curved canals; but XP-endo Finisher R was approximately twice more efficient. The complete filling material removal during re-treatment procedures is still a challenge. Supplementary cleaning protocols may help to remove the remaining material after the complete mechanical preparation of curved canals. XP-endo Finisher R was approximately twice more efficient than PUI.

Sealing ability of mineral trioxide aggregate, Biodentine, and EndoSequence RRM putty used as retrograde restorative material: An in vitro bacterial leakage model study

Sealing ability of mineral trioxide aggregate, Biodentine, and EndoSequence RRM putty used as retrograde restorative material: An in vitro bacterial leakage model study

Measurement Accuracy in Cone Beam Computed Tomography in the Presence of Metal Artifact.

Cone beam computed tomography (CBCT) image quality is known to be affected by artifacts produced by metal restorations, causing image deterioration via bright streaks and loss of gray values in the vicinity of the metallic structure. The aim of the study was to determine the impact of progressively increasing metal artifacts on the measurement accuracy of commonly evaluated points in implant treatment planning. Holes were drilled into porcine mandibles at known distances from the alveolar crest on the buccal and lingual surfaces and filled with gutta-percha. Repeated CBCT images were taken, with progressively increasing amalgam restorations and stainless steel crowns (up to a total of eight restorations per jaw). The imaging field of view (FOV) was of a single site (5 × 5 cm2) in two different locations in the mandible, as well as a full-arch FOV (10 × 5 cm2). Images were taken using clinical settings, and with increased kVp and exposure time, without metal artifact reduction (MAR) corrections. Measurements between the buccal and lingual gutta-percha points on the mandible were performed using a digital caliper and compared to the same measurements taken digitally on the CBCT images. Measurements were obtained with no restorations (baseline) and compared with increasing number of restorations. Comparison between caliper measurements and baseline CBCT with no metal artifact demonstrated differences ranging from 0 to 1.7 mm, with no clear detectable pattern of change related to the restorations. Compared to baseline measurements, scans with amalgam and stainless steel restorations showed a maximum difference of 0.54 ± 0.64 mm and 0.62 ± 0.64 mm, respectively, with no significant differences with increasing metal restorations. There may be a variation of up to 1.7 mm between measured anatomical points and CBCT imaging under commonly used settings. While this result may be clinically important, it does not appear to be affected by increasing metal artifact due to amalgam restorations or stainless steel crowns. The findings of this study support current clinical practices accounting for a safety margin of up to 2 mm with any CBCT image, and not limiting CBCT scans for patients with multiple metal restorations.

Use of micro-CT to examine effects of heat on coronal obturation.

The aim of this study was to categorize the effects of heat on coronal obturation with gutta-percha and sealer using X-ray micro-computed tomography (micro-CT). Ten single-rooted, extracted human teeth were shaped using ProTaper NEXT files to size X5 (#50/Taper 6%) with 2.5% NaOCl irrigation. A single ProTaper NEXT X5 gutta-percha point was then inserted with epoxy resin (AH Plus) or tricalcium silicate (EndoSequence BC) sealer (n = 5/group), and cut at the cemento-enamel junction. The teeth were scanned using micro-CT (SkyScan1272) to obtain 11 sagittal 2-D images. Three calibrated raters categorized the coronal 0.5 mm of the images into four categories: "swirled sealer and/or gutta-percha without voids" (I), "uniform voids and sealer/gutta-percha" (II), "non-uniform voids and sealer/gutta-percha" (III), and "swirled sealer and/or gutta-percha with voids" (IV). Intra-rater and inter-rater reliability were then calculated. Chi-square tests were conducted to determine the significance of differences in each category between sealers. The intra-class correlation coefficient was 0.55 (same rater/two different times) and Fleiss' kappa (different raters/same image) was 0.34. Categories I, II, III, and IV accounted for 16.4%, 4.2%, 30.3%, and 49.1% for AH Plus, and 6.7%, 4.2%, 27.3%, and 61.8% for EndoSequence BC, respectively. Category IV was most common and Category II the least common. Significant differences were evident between sealers for Category I (P < 0.01).

Accuracy of Paper Point Technique for Final Working Length Measurement after Canal Preparation

Objective: The aim this study was to check the accuracy of paper point technique for final working length measurement after canal preparation. Study Design: Randomized controlled trial Place and Duration: Study was performed in department of operative dentistry, Liaquat University of Medical &amp; Health Sciences, Jamshoro for one year duration from January 2017 to December 2017. Methodology: This study was performed on 78 patients divided equally into two groups. In one group working length was established by using electronic apex locator while in second group working length was established by using electronic apex locator with paper point technique. To check the working length master apical gutta percha point (GP point) was inserted into canal and radiograph were taken by paralleling angle technique. Results: There were 34 (43.6%) males while 44 (56.4%) patients were females. Mean age of patients was 30.5±8.9 years. Mean tooth number was 28.8±11.0. Group A is concerned that was treated only with Electronic Apex Locator showed lesser number of acceptable length than group B. on the other hand, group B was treated with electronic apex locator and paper point technique showed higher acceptable length of respondents with a difference of 4 frequencies or 7% in excess. A less value of chi-square test showed relationship between observed and expected data; whereas, significance value indicated no significant difference between group A and B. Conclusion: Paper point technique is as reliable as other techniques for final working length measurement. Key Words: Electronic Apex Locator, Paper Point Technique, Endodontic Working Length

The investigation of thermal behaviour and physical properties of several types of contemporary gutta-percha points.

AimTo analyse the contents and thermal behaviour of several brands of contemporary gutta‐percha points due to the variable nature of the components of gutta‐percha, and the impact they can have on the physical properties of this unique material during canal filling.MethodologySix brands of gutta‐percha were investigated: Conform Fit TM Gutta‐Percha Points for ProTaper Gold® (PTG) (Dentsply Sirona), ProTaper® Universal Gutta‐Percha Points (PTU) (Dentsply Sirona), Autofit TM Feathered Tip Gutta Percha (Kerr), Mtwo® Gutta‐Percha (VDW), Gutta Percha Root Canal Points (GC, GC Corporation) and Gutta‐Percha Points ISO Color‐Coded (ISO; Dentsply Sirona). The organic and inorganic fractions of gutta‐percha points were separated by quantitative chemical analysis. Thermal conductivity was detected using a laser flash method. In addition, the thermal behaviour of gutta‐percha in response to temperature variations was analysed using differential scanning calorimetry (DSC). Kruskal–Wallis and Dunn tests were applied for comparisons amongst groups for chemical compositions and temperature obtained from DSC. The associations between compositions and thermal conductivity were determined using simple linear regression. A p value <.05 was considered to be statistically significant.ResultsThere were significant difference in the inorganic fractions of the gutta‐percha points in percentage by weight amongst the groups (p < .05). PTG had the lowest thermal conductivity (0.42 W/m K). A positive correlation was observed between the percentage of inorganic fraction and thermal conductivity (r = 0.95). The initial phase changing temperature and peak temperature measured by DSC were significantly different when the β‐form transformed to α‐form (p < .05), whereas no significant difference was found during the α‐form to the amorphous‐phase transition (p > .05).ConclusionsChemical compositions and initial phase changing temperature by DSC varied according to the various brands of gutta‐percha points. Conform Fit TM gutta‐percha had the lowest percentage of inorganic fraction and thermal conductivity amongst these six brands of gutta‐percha. Thermal conductivity had the strongest positive correlation with the percentage of inorganic components and zinc, whilst there was a negative correlation to the amount (ratio) of gutta‐percha.

Effect of low-level laser therapy on postoperative pain after single-visit root canal retreatment of mandibular molars: A randomized controlled clinical trial.

To compare the effect of low-level laser therapy (LLLT) on postoperative pain after single-visit root canal retreatment on mandibular molars. This randomized controlled clinical trial included 36 patients referred to the Department of Endodontics, Islamic Azad University, Tehran, Iran. Healthy patients who required root canal retreatment on symptomatic first or second mandibular molars, with a PAI index score of 2 or 3, preoperative tooth and percussion pain of <56mm on a 170-mm visual analogue scale (VAS) were included. After local anaesthesia using inferior alveolar nerve block followed by rubber dam isolation and access cavity preparation, the D RaCe retreatment system was used to remove the existing root filling material, and after canal negotiation and gaining patency, working length was determined with an apex locator. Further canal enlargement was carried out with size 35, 0.04 taper, and size 40, 0.04 taper RaCe rotary instruments and then canals were filled using laterally compacted gutta-percha points and AH Plus sealer. The patients were randomly assigned to treatment groups: In the LLLT group, a 980-nm diode laser set at 6.89W/cm2 energy density, 0.5W power, and a tip diameter of 10mm were activated from the buccal side on the mesial and distal root apices for 15s. In the sham group, the laser handpiece was placed inside the patient's mouth at the same location, but the laser was not activated. Then patients were instructed to record their postoperative pain levels at 4, 8, 12 and 24h and 2, 3 and 7days after treatment on separate VAS scales. For data analysis, the independent sample t and the Mann-Whitney U tests were used. Nominal variables were analysed by using the chi-square test. In the LLLT group, the most intense pain was reported 24 and 48h post-treatment [mean (SD)=0.22 (0.54) for both], whereas in the sham group, the most intense pain level was observed 4h post-treatment [mean (SD)=0.78 (0.80)]. At the 4-h interval, pain intensity was significantly lower in the LLLT group (p=.016). Low-level laser therapy reduced postoperative pain after single-visit root canal retreatment of mandibular molars only four hours following the procedure.

Healing Capacity of Bone Surrounding Biofilm-Infected and Non-Infected Gutta-Percha: A Study of Rat Calvaria

This paper aims to evaluate the healing capacity of bony lesions around biofilm-infected and non-infected gutta-percha (GP) points. Bony defects were created in the calvaria of 28 Wistar rats. The rats were divided into three groups: Group 1—Implantation of infected GP particles in the bony defect; Group 2—Positive control implantation of non-infected GP particles in the bony defect; and Group 3—Negative control, in which no GP particles were implanted. The biofilm consisted of three strains of bacteria: Enterococcus faecalis, Streptococcus sanguis, and Porphyromonas gingivalis. The animals were sacrificed 60 days postoperation, and histological assessments were performed. In Group 1, the biofilm-infected group, we observed a mild foreign body reaction with a few inflammatory cells adjacent to the capsule and a newly woven bone matrix surrounded by osteoblasts and mature bone. In Group 2, the non-infected GP particles group, minimal inflammatory cell reactions were observed in the adjacent tissue, and a newly woven bone matrix was surrounded by osteoblasts. This study shows that bone healing is possible around both sterile and infected GP points. This contradicts the claim that some root canal treatments fail because of non-microbial factors, including extruded root canal filling materials, which may cause foreign body reactions. The healing observed suggests that overextension should not be considered an indication for endodontic surgery.

Evaluation of the apical microleakage of three different root-end filling materials

Background: Attempts for preserving endodontically treated teeth after root canal treatment failure have directed the clinicians to surgical intervention; apicectomies with root end resection followed by placement of root-end filling material. Different techniques are used to assess the quality of the apical seal obtained by root end filling materials. Dye penetration is considered the most popular technique. Objective: this in vitro study aimed to evaluate and compare the apical microleakage of three root- end filling materials. Methods: Twenty one upper incisors were utilized, root canals instrumentation was achieved by ProTaper system. Obturation was conducted by lateral condensation technique using Protaper universal gutta percha points. Teeth were apically resected at an angle of 90° to the long axis of the root and root end cavities were prepared and filled. The samples were coated with varnish, then were immersed in 2% methylene blue solution for 24 hours. Roots were then sectioned bucco-lingually in a longitudinal direction. Extent of dye penetration was detected by the use of stereomicroscope. Results: The highest mean value was recorded in MTA group, followed by Guttaflow bioactive and Endoseal groups, where both almost recorded the same mean values. Tukey’s post hoc test revealed no statistically significant difference between the three tested groups. Conclusion: it can be concluded that; all the three groups showed microleakage and none of the three root-end filling materials was able to achieve perfect apical seal. The result also showed that guttaflow bioactive provides a similar reliable seal compared to MTA Fillapex and Endoseal MTA.