Assessment of dental students' knowledge and performance of master gutta-percha cone selection and fitting during root canal treatment: a pilot study.

BACKGROUND: Misconceptions should be detected early in dental students' training to improve their clinical performance. Accordingly, this study aimed to assess undergraduate dental students' knowledge and performance of master gutta-percha (GP) cone selection and fitting during clinical endodontic courses at the College of Dentistry, King Saud University. METHODS: Ninety-nine undergraduate dental students completed an online survey about their knowledge of master GP cone selection. Forty-five of these students were observed by faculty members in clinical endodontic courses while they fitted master GP cones during root canal treatments. The observers recorded the details of each student's cone-fitting techniques. The data were analysed using t-tests, one-way analysis of variance, and chi-square tests (p < 0.05). Inter- and intra-observer reliability were tested using Fliess' Kappa. RESULTS SURVEY: All participants had good knowledge of over-extended cone management, while 80.8% knew how to properly manage a short cone. The proper flaring assessment method was selected by 86.9% of the female and 34.2% of the male students, and this difference was statistically significant (p = 0.0001). OBSERVATION: The students labelled the working length on the master GP cone with an indentation in 64.4% of the cases and by bending the cone 35.6% of the time. Of all students, 84.4% encountered an apical stop, and this rate correlated significantly with the length of the cone on the master apical cone radiograph (p = 0.001). Improper shaping of the canal was the most common cause of ill-fitting cones (83.3%), while 16.7% of the students chose the wrong cone size. The final obturation length was adequate in 80% of the cases; 57.8% of the students were helped by instructors. CONCLUSIONS: Most students had the basic knowledge required to solve problems related to the selection of master GP cones. However, in the clinical setting, more than half of the students required the assistance of an instructor to adjust their cone's fit. The presence of an apical stop had the most significant effect on the length of the fitted master GP cone on radiography. The most common cause of ill-fitting master cones was improper shaping of the canal.

Impact of low-fusion gutta-percha cones used in variations of the continuous wave condensation technique with filling sealers based on bioceramic compounds on the quality of root canal filling.

To evaluate the impact on the quality of filling with of low-fusion and conventional gutta-percha cones. Thirty-six maxillary canines were prepared and divided into three groups: I-conventional cone with Downpack at 200 °C at 4 mm from the WL; II-low-fusion cone with Downpack at 100 °C up to 4 mm from the WL; III-low-fusion cone with Downpack at 100 °C up to 7 mm from the WL. Temperature variations were measured in thirds on the external surface of the root. The bond strength was evaluated using the push-out test. The adhesive interface was analyzed by scanning electron microscopy. The bond strength and the temperature variation data were analyzed using analysis of variance and the failure type using the chi-square test. The low-fusion cone group with 7 mm Downpack showed higher bond strength (4.2 ± 2.7) compared with conventional cones (2.8 ± 1.6) and low-fusion cones with 4 mm Downpack (2.9 ± 1.6) (p < 0.05), with occurrence of a higher number of adhesive failures to the filling material and mixed failures. Relative to temperature variation, there was less temperature change in the apical third, in the low-fusion cone with Downpack 7 mm (1.0 ± 1.0) (p < 0.05). The use of low-fusion cones allowed the continuous wave condensation technique to be performed at a lower depth of Downpack at 100 °C at 7 mm, with less heating in the apical third, without compromising the quality of filling. Using gutta-percha cones with low fusion, which permits a lower condensation temperature and reduced Downpack depth, maintains the quality of filling, in order to minimize possible damage to the periapical tissues.

Degree of Contamination of Gutta-Percha Points by Staphylococcus aureus (MRSA/MSSA) Strains.

Methicillin-resistant Staphylococcus aureus (MRSA) is considered one of the most harmful bacteria to human health. Dentistry, like all healthcare disciplines, places great emphasis on preventing scenarios that may result in cross-infection. Although various tested and already used materials are suitable for filling the root canal system, Gutta-Percha (GP) remains the preferred and widely accepted gold standard. OBJECTIVE: We performed an in vitro analysis of the contamination of GP points, regarding the strains of Methicillin-resistant (MRSA) and Methicillin-sensitive (MSSA) Staphylococcus aureus, using classical microbiology methods and molecular biology techniques. METHODS: Gutta-Percha points of two different brands from opened packages (already in use for 1 month) were collected for analysis. The assessment involved incubating the GP points in Brain Heart Infusion (BHI) medium to detect microbial growth. Growing microorganisms were plated on a selective and differential chromogenic medium for MRSA/MSSA strains, and the identification of isolates was confirmed by Polymerase Chain Reaction (PCR). In the case of microbial growth, the GP point was submitted to a disinfection protocol. RESULTS: From the 315 collected GP points, only 6 (1.9%) resulted in being positive for microbial growth. After confirmation by PCR, only one sample of the six GP points was contaminated by MRSA, and the remaining five were MSSA-contaminated. The disinfection protocol was effective in all contaminated GP points. CONCLUSIONS: The Gutta-Percha points from opened pre-sterilized packages showed a very low degree of contamination by MRSA/MSSA. However, the detection of MSSA and MRSA strains raises concerns about potential contamination in dental clinic environments, and this risk cannot be considered negligible.

Nanostructured ZnO thin film to enhance gutta-percha's adhesion to endodontic sealers.

BACKGROUND: Gutta-percha (GP) combined with an endodontic sealer is still the core material most widely used for tridimensional obturation. The sealer acts as a bonding agent between the GP and the root dentinal walls. However, one of the main drawbacks of GP core material is the lack of adhesiveness to the sealer. ZnO thin films have many remarkable features due to their considerable bond strength, good optical quality, and excellent piezoelectric, antibacterial, and antifungal properties, offering many potential applications in various fields. This study aimed to explore the influence of GP surface's functionalization with a nanostructured ZnO thin film on its adhesiveness to endodontic sealers. METHODS: Conventional GP samples were divided randomly into three groups: (a) Untreated GP (control); (b) GP treated with argon plasma (PT); (c) Functionalized GP (PT followed by ZnO thin film deposition). GP's surface functionalization encompassed a multi-step process. First, a low-pressure argon PT was applied to modify the GP surface, followed by a ZnO thin film deposition via magnetron sputtering. The surface morphology was assessed using SEM and water contact angle analysis. Further comprehensive testing included tensile bond strength assessment evaluating Endoresin and AH Plus Bioceramic sealers' adhesion to GP. ANOVA procedures were used for data statistical analysis. RESULTS: The ZnO thin film reproduced the underlying surface topography produced by PT. ZnO thin film deposition decreased the water contact angle compared to the control (p < 0.001). Endoresin showed a statistically higher mean bond strength value than AH Plus Bioceramic (p < 0.001). There was a statistically significant difference between the control and the ZnO-functionalized GP (p = 0.006), with the latter presenting the highest mean bond strength value. CONCLUSIONS: The deposition of a nanostructured ZnO thin film on GP surface induced a shift towards hydrophilicity and an increased GP's adhesion to Endoresin and AH Bioceramic sealers.

Marginal adaptation of customized gutta percha cone with calcium silicate based sealer versus MTA and biodentine apical plugs in simulated immature permanent teeth (an in vitro study).

BACKGROUND: This study aimed to compare the marginal adaptation of a single customized gutta percha cone with calcium silicate-based sealer versus mineral trioxide aggregate (MTA) and Biodentine apical plugs in simulated immature permanent teeth. METHODS: Thirty-nine extracted human maxillary anterior teeth were selected, prepared to simulate immature permanent teeth with an apical diameter 1.1 mm, placed in moist foam and divided into three groups. Group 1: Obturation with a single customized gutta percha cone and calcium silicate sealer. Group 2: MTA apical plug. Group 3: Biodentine apical plug. After incubation, teeth were horizontally sectioned at 1 mm and 3 mm from the apex and marginal adaptation was evaluated using scanning electron microscope (SEM). RESULTS: Biodentine showed the least mean gap size at both 1 and 3 mm from the apex with no statistically significant differences compared to MTA (p > 0.05). The single customized cone with calcium silicate based sealer showed the greatest mean gap size at both 1 and 3 mm from the apex with a statistically significant difference compared to the other groups (p < 0.001). CONCLUSION: Biodentine and MTA apical plugs provide a significantly better marginal adaptation to the dentinal walls than a single customized gutta percha cone with calcium silicate based sealer in simulated immature permanent teeth.

Effectiveness of root canal filling materials and techniques for treatment of apical periodontitis: A systematic review.

BACKGROUND: Apical periodontitis (AP) is an inflammatory disease of the apical periodontium as sequelae of pulp death. It is managed by disinfection and filling of the root canal space. OBJECTIVES: The aim of this systematic review was to investigate whether obturation techniques and materials used for root canal filling led to the management of AP. METHODS: A systematic review protocol was written following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist and registered on the international prospective register of systematic reviews (PROSPERO; CRD42021260275) including two populations, interventions, comparisons, outcomes and time (PICOT) for the research questions querying the effectiveness of obturation techniques (PICOT 1) and materials (PICOT 2) for the management of AP. Electronic searches were conducted on PubMed, ScienceDirect, Scopus and Embase search engines. Searches on International Endodontic Journal, Journal of Endodontics, Clinical Oral Investigations, Journal of Dental Research and Journal of Dentistry websites were also conducted, until May 2021. Both primary (tooth survival) and secondary outcomes were evaluated. The risk of bias was assessed by Cochrane RoB2 for the randomized and ROBINS-I for the nonrandomized trials. RESULTS: The search strategy identified 1652 studies, with 1600 excluded on the title and abstract screening, leaving 52 studies for full-text screening. In total, 10 studies met the inclusion criteria. The obturation technique and materials used did not affect the outcome of AP. Vertical compaction resulted in faster resolution of periapical lesions. The oral health-related quality of life of patients treated with lateral condensation exhibited poorer outcomes compared with single matched cone after 6 months of recall. DISCUSSION: The inclusion and exclusion criteria used for this systematic review enabled the capture of all the literature available on the effect of obturation techniques and materials on the outcome of AP. The data were heterogenous, and a number of articles investigating obturation techniques had no information on the materials and techniques used as they looked at the quality of fill. CONCLUSIONS: Included studies did not find any difference between different procedures (PICOT 1) and materials (PICOT 2). The risk of bias was high, thus the findings should be interpreted with caution. REGISTRATION: PROSPERO registration number: CRD42021260275.

Postoperative pain of single-visit endodontic treatment with gutta-percha versus MTA filling: a randomized superiority trial.

BACKGROUND: Postoperative pain has remained a challenge for clinicians. This randomized superiority trial compared the levels of postoperative pain following the use of gutta-percha (GP) and sealer or mineral trioxide aggregate (MTA) as root canal filling materials in teeth with asymptomatic apical periodontitis. METHODS: A total of 119 patients were initially evaluated in this two-arm, parallel-group, single-blind, superiority randomized trial. The inclusion criteria were participants aged 18-65 years with single-canal premolars diagnosed with asymptomatic apical periodontitis. The participants were finally divided into two groups using the permuted block randomization method. In the GP group (N = 46), the cleaned and shaped root canals were filled with gutta-percha and AH Plus sealer, while in the MTA group (N = 48), the cleaned and shaped root canals were filled with an MTA apical filling and a coronal gutta-percha and sealer. Patient pain level was measured 6, 12, 24, 48, and 72 h postoperatively using a 10-point visual analog scale (VAS). The data were analyzed by the chi-square, independent t, Friedman, and Mann-Whitney U tests. RESULTS: The mean of VAS scores decreased significantly over time in both groups (P < 0.001). The mean VAS scores were significantly lower in the MTA filling group than in the other group (P < 0.05). Female patients reported higher VAS scores at 6- and 12-hour periods in both groups (P < 0.05). CONCLUSION: MTA as a root canal filling material might be a valuable option for clinicians due to its low postoperative pain. TRIAL REGISTRATION: The trial protocol was registered at the Registry of Clinical Trials (IRCT20191104045331N1).

Biocompatibility of three different root canal sealers, experimental study.

OBJECTIVES: This study was assessed the biocompatibility of three different root canal sealers (Well-Root St, GuttaFlow Bioseal, and AH-Plus) following implantation in rat subcutaneous tissues, using histopathological immunohistochemical analysis. METHODS: Four groups of eighty-four male rats each underwent subcutaneous dorsal implantation of a polyethylene tube, either empty or filled. Tissues were collected, fixed, and processed for histological analysis after 7, 15, and 30 d. Slides were photographed and digitally processed to identify lymphocytes and macrophages using Cluster of differentiation 3 (CD3) and cluster of differentiation 68 (CD68) markers, respectively. P was set at 0.05, when lymphocyte and macrophage infiltration was compared between groups and observation times using one-way analysis of variance (ANOVA). RESULTS: Histopathological analysis of all groups revealed an inflammatory reaction followed by the emergence of a fibrous capsule after 7 days. After 30 days, the thickness of the fibrous capsule and the inflammatory response subsided. CD3 staining for immunohistochemical analysis revealed that the AH-Plus group had the highest mean percentage of lymphocyte infiltration at 7 and 15 days, followed by the Well-Root St, GuttaFlow Bioseal, and Control groups. After 30 days, no discernible difference was observed between the groups in terms of the mean percentage of lymphocyte infiltration. After 7, 15, and 30 days, there was a significant difference in the mean percentage of macrophage infiltration across the groups, as demonstrated by CD68 staining. After 7, 15, and 30 days, the AH-Plus group had the highest mean percentage of macrophage infiltration, followed by the Well-Root St. and GuttaFlow Bioseal groups, while the control group had the lowest mean percentage. CONCLUSION: All observational periods showed minimal inflammatory reactions to GuttaFlow Bioseal. After subcutaneous tissue implantation in a rat model, the initial inflammatory reactions to Well-Root St and AH-Plus had abated by day 30, and all tested sealers had outstanding biocompatibility.

Efficiency and complications in root canal retreatment using nickel titanium rotary file with continuous rotation, reciprocating, or adaptive motion in curved root canals: a laboratory investigation.

BACKGROUND: It is currently unknown whether rotary file motion affects the best outcome of root canal retreatment. This experimental study compared the efficacy, efficiency, and complications of single-use NiTi rotary files using continuous rotation, reciprocating, and adaptive motions in root canal filling removal in curved root canals. Reciproc blue R25 was used with reciprocating motion (RB), VDW.ROTATE retreatment files with continuous rotation (VR), and ProTaper NEXT X2 with continuous rotation (PTNc) or adaptive motion (PTNa). METHODS: Forty mesial root canals of extracted mandibular first and second molars with an angle of curvature between 20°-40° and a radius of curvature between 5 and 10 mm were collected. The specimens were instrumented and obturated with gutta-percha and AH Plus sealer using the continuous wave of condensation technique. The specimens were randomly divided into 4 retreatment groups (n = 10), RB, VR, PTNc, and PTNa. The percentage of root canal filling removal in each group was analyzed using Micro-Computed Tomography (µCT). The motor running time, total time, root canal complication, and instrument complication were recorded and statistically analyzed (p-value < 0.05). RESULTS: The pre-operative root canal curvature and root canal filling volume were comparable among groups. The percentage of root canal filling removal from the whole canal in the PTNc, RB, PTNa, and VR group was 98%, 96%, 95%, and 93%, respectively. A significant difference was observed between the PTNc and VR groups for the whole canal and the apical-third part. The motor running time and total time were significantly different between the groups. Instrument fracture was observed at 40% in the VR and 20% in the PTNa group, but none in the RB and PTNc groups. CONCLUSIONS: The ProTaper NEXT X2 with continuous rotation and RB files can be used with high efficacy and efficiency in curved root canal retreatment. Continuous rotation is more efficacious and efficient than adaptive motion when using the NiTi rotary file. Single file retreatment can be used in small canals with high efficacy, cost-effectiveness, and less time consumption.

Radiographic Evaluation of the Gap between Cemented Post and Remaining Gutta-Percha in Endodontically Treated Teeth Performed by Undergraduate Students: A Retrospective Cross-Sectional Study.

The coronal seal in root canal-treated teeth may be compromised depending on the accuracy of post space preparation and post cementation along with remaining gutta-percha. Root canal treatment can be compromised by endotoxins released by the coronal bacteria as a result of microleakage. The study was conducted by undergraduate students to measure the gap between the cemented post and residual gutta-percha. In total, 217 endodontically treated teeth were evaluated with intraoral peri-apical radiographs. Based on the intraoral periapical radiographic examination in the CS-R4 program, Group I had no gap, Group II had a gap of >0 to 2 mm, and Group III had a gap of more than 2 mm between the end of the cemented post and the remaining gutta-percha. In total, 40% (n = 87) of the teeth had no gap, 59% (127) had a gap of >0 to 2 mm, and 1% (n = 3) had a gap of more than 2 mm between the cemented post end and remaining gutta. Chi square test revealed a significant difference in the gap between the post and remaining gutta-percha between males and females students (p < 0.001). In terms of the gap between the cemented post end and the residual gutta-percha, the root canal treated teeth with post and core by undergraduates were clinically acceptable.