Direct restorations of root filled teeth

© 2014 Dr. Nessrin Ahmad TahaRoot filled teeth are weakened by loss of strategic tooth structure through restorative procedures and caries, rather than by the endodontic procedures. In this context, the importance of a restoration which provides cuspal coverage has been highlighted, which incurs further removal of tooth structure and a higher cost. Direct restorations using resin composite materials have been advocated to save time and money while utilizing the bonding ability of these materials to tooth structure. However disadvantages of resin composites including polymerization shrinkage and subsequent problems of leakage, secondary caries and tooth fracture, have limited their adoption as an alternative restorative technique. The purpose of this project was to investigate direct resin composite restoration performance as a permanent filling in root filled teeth, in terms of cuspal movement, strain, microleakage and fracture strength in extracted teeth. In addition, the effect of various test conditions to simulate the clinical environment was investigated: periodontal ligament simulation, thermocycling and mechanical cycling. We also aimed to explore fracture patterns and mechanisms of fracture propagation and approaches to optimize the performance of bonded direct resin composites, including the use of low shrink resin composites, laminate restorations (closed sandwich technique and the open sandwich technique) with conventional and resin modified glass ionomer cements, to find out whether resin composites can restore strength and marginal integrity to serve as a long term functional restoration. It was found that laminate restorations had beneficial effects in terms of reducing cuspal deflection and marginal seal, with acceptable fracture strength. Thermocycling resulted in deterioration of the sealing ability of conventional glass ionomer cements, while neither thermocycling nor periodontal ligament simulation affected the fracture strength. Fracture is a two-step process: firstly interfacial debonding at the buccal or palatal interface, and secondly cuspal fracture beginning at the buccal line angle at the floor of the cavity. Both fracture and failure occurred in a consistent manner regardless of the cavity design, restorative technique (with or without a base) or the loading pattern (cyclic vs. ramped). Failure was predominantly adhesive and biphasic; after debonding the cusp is unsupported and may fracture immediately with the weakest point being the dentine-adhesive interface. Lines of evidence for this phenomenon were derived from load displacement curves, results from staining with methylene blue, micro CT images and crack propagation gauges. Furthermore SEM study of the fractured interface provides strong evidence for propagation of the interfacial crack from gingival to occlusal; with the occlusal interface the last region to fail. Therefore modifications that can reduce or eliminate the stress concentration at the interface may increase the force required to initiate or propagate a crack through this area

Dissolution of a mineral trioxide aggregate sealer in endodontic solvents compared to conventional sealers

Abstract The aim of this study is to evaluate the solubility of a Mineral Trioxide Aggregate sealer (MTA-Fillapex) compared with five other sealers, calcium hydroxide (Sealapex), resin (Realseal), zinc oxide-eugenol (Tubli-Seal), and two epoxy resins (AH-26 and AH-Plus), in chloroform and eucalyptoil in static and ultrasonic environments. Samples of each sealer were prepared (n = 180) and then divided into 12 groups that were immersed in solvents for 5 and 10 min in static and ultrasonic environments. The mean weight loss was determined, and the values were compared using Student’s t-test, One-way ANOVA, and Tukey’s HSD post-hoc test (p 0.05). In conclusion, MTA-Fillapex was not sufficiently dissolved in either solvent. Ultrasonic activation had limited effectiveness on MTA-Fillapex dissolution, whereas it significantly increased the efficiency of solvents in dissolving a number of endodontic sealers

Root canal morphology of anterior permanent teeth in Jordanian population using two classification systems: a cone-beam computed tomography study

Abstract Background Adequate knowledge of root canal morphology and its variation is essential for success of root canal treatment and to overcome treatemnt failure. The aim of this study was to investigate the root and canal morphology of mandibular anterior teeth using 2 classification systems. Methods 3342 lower anteriors were evaluated from 557 CBCT scans. The images were examined in sagittal, axial and coronal views using a CS 3D imaging software (V3.10.4, Carestream Dental). Demographic data recorded, the number of roots and canal’s morphology were described according to Vertucci and Ahmed classifications. Results Frequency of Type I configuration was significantly the highest in incisors and canines (76%, N = 2539), followed by Type III (20.6%, N = 687). Type II (1.1%, N = 37), IV (1.1%, N = 37), and V (0.3%, N = 11) were rarely encountered. 0.9% (N = 31) of the teeth could not be classified with the Vertucci System. The frequency of 2 roots (2MA in Ahmed classification) which has no correspondence in the Vertucci classification, was 1.1% (N = 38), it was significantly higher in canines and in females (35 canines and 3 laterals). A moderate correlation in root canal morpology was found between the left and right sides (V > 0.30). 80% (N = 2538) of the teeth did not exhibit any divergence/merging. The bifurcation level occurred mostly in the middle third of the root. Conclusions One fourth of anterior teeth had variation from the simple type I canal configuration and therefore requires attention during treatment. The new classification system offers a more accurate and simplified presentation of canal morphology. Clinical relevance The prevalence and mid root bifurcation of second canal in lower anteriors requires attention to ensure adequate quality root canal treatment without compromising the integrity of teeth

Conservative Management of Mature Permanent Teeth with Carious Pulp Exposure

International audienc

Original research Dental Materials Dissolution of a mineral trioxide aggregate sealer in endodontic solvents compared to conventional sealers

Abstract: The aim of this study is to evaluate the solubility of a Mineral Trioxide Aggregate sealer (MTA-Fillapex) compared with five other sealers, calcium hydroxide (Sealapex), resin (Realseal), zinc oxide-eugenol (Tubli-Seal), and two epoxy resins (AH-26 and AH-Plus), in chloroform and eucalyptoil in static and ultrasonic environments. Samples of each sealer were prepared (n = 180) and then divided into 12 groups that were immersed in solvents for 5 and 10 min in static and ultrasonic environments. The mean weight loss was determined, and the values were compared using Student's t-test, One-way ANOVA, and Tukey's HSD post-hoc test (p < 0.05). In chloroform, MTA-Fillapex, AH-26, and Sealapex displayed moderate solubility with no significant difference in dissolution (p = 0.125); however, their dissolution was significantly lower than that of AH-Plus (p < 0.001), which was almost fully dissolved after 10 minutes. Realseal was significantly less soluble than all sealers (p < 0.001). In eucalyptoil, MTA-Fillapex showed low solubility, as all of the sealers did, but Tubli-Seal was significantly more soluble than other sealers (p < 0.001). Using ultrasonic activation resulted in a significantly higher dissolution rate in chloroform for all sealers except MTA-Fillapex after 10 min (p = 0.226). In eucalyptoil, ultrasonic activation significantly increased the dissolution rate of all sealers except MTA-Fillapex after 5 and 10 min, Sealapex at 10 min, and AH-Plus at 5 min (p > 0.05). In conclusion, MTA-Fillapex was not sufficiently dissolved in either solvent. Ultrasonic activation had limited effectiveness on MTA-Fillapex dissolution, whereas it significantly increased the efficiency of solvents in dissolving a number of endodontic sealers

Leveling the curve of Spee using different sized archwires: a randomized clinical trial of blood flow changes.

To compare blood flow (BF) changes of teeth subjected to orthodontic forces during curve of Spee (COS) leveling using different archwires (AW). Thirty subjects with COS > 5 mm were randomly assigned (1:1:1) into three groups based on the AW used: group 1: 0.017 × 0.025-inch stainless-steel (SS)AW, group 2: 0.019 × 0.025-inch SSAW, and group 3: 0.021 × 0.025-inch β-titanium (TMA)AW. In the 3 groups, a 5 mm-depth reverse COS was placed in the AWs. A laser Doppler flowmeter was used to measure BF at different time intervals (T0-T4). In the 3 AWs group, BF of all measured teeth was reduced 20 min after force application. Afterwards, the BF values started to increase until the baseline values were almost restored within 1 week. Differences in BF changes between the extrusion and intrusion subgroups were observed within groups 1 and 3 during the first 20 min of force application (P < 0.05). Similar BF changes were recorded using the 3 different AWs. BF changes were associated with tooth type and the amount of COS depth change. During CoS leveling, similar BF changes were recorded using the 3 different AWs. Tooth type and the amount of COS depth change were associated with BF changes within the first 20 min of force application. Greater BF reduction was found in premolars compared to incisors during the first 20 min of AW placement. It is important to select a type of applied forces that minimally affect the BF. Intrusive forces appeared to have lower negative effects on the BF of teeth during COS leveling. ClinicalTrial.gov (# NCT04549948).Open Access funding provided by the Qatar National Library. The study was supported by the Deanship of Research at the Jordan University of Science and Technology, research grant number (436/2018)

Attitude and practice of regenerative endodontic procedures among endodontists and paediatric dentists:A multinational survey from 13 countries

Background: Regenerative endodontics (RET) refers to biologically based procedures that aim to restore damaged tooth structures and reinstate the pulp–dentine complex to its normal physiological state. Aim: The purpose of this study was to examine the attitudes and practices of endodontists and paediatric dentists regarding RET. Design: A survey was conducted among endodontists and paediatric dentists from 13 countries. A number of factors were evaluated, including frequency of RET application, followed guidelines, disinfection techniques, intracanal medication type, scaffold type, preferred coronal seal material, and follow-up period. Results: Among the 1394 respondents, 853 (61.2%) and 541 (38.8%) were endodontists and paediatric dentists, respectively. Almost half (43%) of participants have not performed RET yet. The American Association of Endodontics guideline (47.3%) was selected as the primary source for the clinical protocol. The most frequently selected irrigant solution was 1.5%–3% NaOCl at the first (26.1%) and second (13.6%) sessions. A blood clot (68.7%) and MTA (61.9%) were the most frequently selected scaffold type and coronal barrier. Most participants preferred a 6-month follow-up period. Conclusion: According to this survey, deviations exist from current RET guidelines regarding all aspects evaluated. Standardizing clinical protocols and adhering to available guidelines would help to ensure more predictable outcomes.</p

Assessment of the Prevalence of Middle Mesial Canal in Mandibular First Molar: A Multinational Cross-sectional Study with Meta-analysis

Background: An additional canal found in the mandibular first molar (M1M) is the middle mesial canal (MMC), which is often missed during root canal treatment. In this study, the prevalence of MMC in M1M on cone-beam computed tomography (CBCT) images was evaluated in 15 countries, along with the effect of some demographic factors on its prevalence. Methods: Deidentified CBCT images were scanned retrospectively, and the ones including bilateral M1Ms were included in the study. A written and video instruction program explaining the protocol to be followed step-by-step was provided to all observers to calibrate them. The CBCT imaging screening procedure consisted of evaluating three planes (coronal, sagittal, and axial) after a 3-dimensional alignment of the long axis of the root(s). The presence of an MMC in M1Ms (yes/no) was identified and recorded. Results: In total, 6304 CBCTs, representing 12,608 M1Ms, were evaluated. A significant difference was found between countries (P .05) or between genders (odds ratio= 1.07, 95% CI: 0.91, 1.27; P > .05). As for the age groups, no significant differences were found (P > .05). Conclusions: The prevalence of MMC varies by ethnicity, but it is generally estimated at 7% worldwide. Physicians must pay close attention to the presence of MMC in M1M, especially for opposite M1Ms, due to the prevalence of MMC being significantly bilateral