ENDO, 03/2017

Periapical lesions regularly occur in untreated teeth, as well as in teeth that have already been subjected to endodontic treatment. There are various known factors that lead to effective endodontic treatment where the clinical symptoms disappear and the periapical lesion disappears or decreases in size. The risk of painful inflammation alongside a persistent periapical lesion is small, even if the periapical lesion has increased in size. The survival of a tooth with a periapical lesion that has undergone root canal treatment is 87% after 10 years. In cases where an endodontically treated tooth has to be extracted, a restorative problem is often the reason for extraction, while a persistent periapical lesion has a limited effect on tooth loss. There are insufficient data available on the effect of a periapical lesion on general health. Keywords: effectiveness, general health, pain, periapical lesion, survival

Vertical root fractures (VRF) are longitudinally orientated, complete or incomplete cracks that can occur on the tooth root at any level and usually initiate from the internal root canal wall. VRFs commonly occur in root canal-filled teeth and may result in the loss of the affected tooth. A PubMed search to April 2017 was completed using the key words "vertical root fractures", "endodontic treatment" and "root-filled teeth". Abstracts were read to identify relevant articles before retrieval. A search of reference lists identified further studies and 62 articles were selected. Diagnosis of VRFs can often be challenging. The combined use of history taking, periodontal probing and periapical radiographs is essential. The aetiology is multifaceted and includes predisposing factors such as tooth type, root canal morphology, and iatrogenic factors involving materials and devices used in root canal treatment and for post space preparation. Emerging risk factors such as implant-associated VRF have recently been identified. Prevention of VRF includes conservation of dentine during root canal instrumentation, appropriate choices of materials for preparation, irrigation and disinfection and avoiding excessive forces during lateral and vertical condensation of gutta-percha (GP). Cracks formed during root-end preparations in apical surgery may also lead to VRF, and teeth with the "butterfly effect" seem to be more at risk. Traditionally, treatment of VRFs has been tooth extraction. Alternative treatments such as bonding of separated root fragments followed by intentional replantation have gained some momentum. Keywords: cracks, root canal filling, vertical root fracture

Aim: The aim of this study was to compare the ability of two reciprocation motion file systems with a continuous rotary system for preparing simulated canals by undergraduate dental students. Methods: Following clinical demonstration and instructions, 84 undergraduate dental students prepared three endodontic training blocks; first using the continuous rotary motion file system (ProTaper Universal) then two reciprocation motion file systems (WaveOne and Reciproc), following manufacturers' instructions, in a crossover study design. Data on preparation time, user preference and procedural errors including ledges, apical zips, file separation, canal transportation and over-preparation were collected. All preparations were assessed using high magnification digital images by three observers. Data analysis was performed using logistic mixed modelling and odds ratios were calculated comparing the methods. Results: Both reciprocation systems exhibited fewer procedural errors than ProTaper Universal. The odds of an error occurring were significantly higher when using Reciproc compared with WaveOne. The odds ratio was 2.8, with a 95% confidence interval of 1.2 - 6.7 (P = 0.020). ProTaper Universal resulted in the highest incidence of ledges (22.6%), separations (10.7%) and transportations (14.3%). The Reciproc system resulted in the highest incidence of both apical zips (6.0%) and over-preparation (8.3%). No file separation occurred while using both reciprocating systems. Conclusions: Both reciprocation systems produced fewer procedural errors than the continuous rotary system. The results with WaveOne were favourable, with a low incidence of procedural errors, a higher student preference and the shortest preparation time. Keywords: outcome, procedural errors, ProTaper, Reciproc, reciprocation, WaveOne

Objective: The aim of the study was to compare microleakage and marginal adaptation of White Mineral Trioxide Aggregate (WMTA), Biodentine and chemical-cured glass ionomer cement (GIC) as root-end filling materials using the dye extraction method and scanning electron microscope (SEM). Materials and Methods: The study used 90 extracted human mandibular premolar teeth. After the instrumentation and obturation of root canals, the apical 3 mm of the roots were resected perpendicular to their long axes. Root-end cavities were prepared using diamond-coated ultrasonic retrotips. Samples were divided into three experimental groups according to the root-end filling material used (n = 30): WMTA, Biodentine, and EQUIA-Fil GIC. Each group was subdivided into two sub-groups A and B. Samples in sub-group A were evaluated for microleakage using the dye extraction method, while those in sub-group B were evaluated for marginal adaptation using SEM. The obtained results were analysed statistically using ANOVA and Tukey tests. The significance level was set at 5% (P ≤ 0.05). Results: WMTA had the lowest mean dye absorbance value and the smallest interfacial gap width followed by Biodentine and EQUIA-GIC, with no significant difference between them. Conclusion: WMTA, Biodentine and chemical-cured GIC demonstrated comparable sealing ability as root-end filling materials. Keywords: Biodentine, glass ionomer cement, Mineral Trioxide Aggregate, periapical surgery, tricalcium silicate

Aim: To compare the adaptation of thermo-plasticised root canal fillings performed in oval canals instrumented with three file systems, and its potential association with debris remaining in recesses. Material and Methods: Thirty-nine mandibular incisors with oval canals were instrumented with WaveOne, ProTaper Universal files or with the self-adjusting file (SAF) system (n = 13). Root canal fillings were performed with Thermafil, with no sealer. The roots were then cut at 2.0, 3.5, 5.0, 6.5 and 8.0 mm from the apex. Morphometric measurements established the percentage of canal area containing no root canal filling material (ANFM). The presence of debris, as a potential cause for defective adaptation, was evaluated microscopically. ANOVA with repeated measures and the Chi-square test were used; significance was set at P < 0.05. Results: The apical, round part of the canal showed effective filling with no difference between the file systems. In the oval part of the canal, ≥ 3.5 mm from the apex, the WaveOne and ProTaper Universal groups presented means of 15.2 (± 12.4)% and 12.1 (± 7.5)% of ANFM, respectively, and did not differ from each other. The SAF group had a mean of 6.4 (± 7.9)% of ANFM, which differed significantly from the other two groups (P = 0.001). Deficiencies in filling were associated with the presence of debris in un-instrumented recesses. Conclusions: The adaptation of thermo-plasticised gutta-percha in oval canals was affected by debris remaining or packed into un-instrumented canal recesses. Using the SAF system was associated with less debris and with better adaptation, as compared with the rotary or reciprocating files. Keywords: debris, ProTaper Universal, oval canal, self-adjusting file, thermo-plasticised root fillings, WaveOne

Under normal circumstances, teeth are resistant to the ravages of external invasive resorption (EIR), as odontoclasts cannot attach to a root surface that is covered by a precemental organic layer. However, when that layer is missing or damaged, which may be due to multiple factors, EIR may occur and move through the cementum and dentine. When this occurs there is usually a characteristic radiographic appearance in which the resorptive process moves longitudinally in the dentine without penetrating the organic predentine that protects the pulp. When superimposed by inflammation and/or bacterial contamination, the pulpal space may also be penetrated. This type of resorptive process is more commonly seen in cases of invasive cervical resorption; however it can occur more apically, in which case it would be considered invasive radicular resorption. This case report provides an in-depth assessment of invasive radicular resorption in a mandibular premolar using magnified, high-definition, visual evaluation and µCT sections to provide the clinician with a better understanding of this malady. Keywords: external invasive resorption, micro-CT, odontoclasts, radicular resorption, radiographs

Objective: The purpose of this study was to compare the solubility, pH, calcium ion release and setting time of Biodentine, Bioactive glass, nano Biodentine and nano Bioactive glass. Materials and Methods: For solubility, pH changes and calcium ion release, the tested specimens were immersed in distilled water. The evaluation was performed after 1 h, 24 h and 7 days. The pH values were measured using a digital pH meter. The measurement of calcium ion release was completed using atomic absorption spectrophotometry. The setting time was measured using a Vicat apparatus. Data were analysed by the One Way ANOVA test followed by the Tukey post-hoc test at P ≤ 0.05. Results: Nano Biodentine showed significant highest mean pH values up to the seventh day, highest calcium ion release at all experimental periods and the shortest setting time (P ≤ 0.001). On the other hand it showed the greatest solubility, while Bioactive glass and nano Bioactive glass showed negative solubility. Conclusions: Nano Biodentine showed the highest alkalinizing action, offered a superior affinity to release calcium ions and a distinct short setting time, but with high solubility. Keywords: Bioactive glass, Biodentine, nano Bioactive glass, nano Biodentine, physicochemical properties

Aim: To compare the efficacy of XP-Endo finisher file (XP) (FKG Dentaire, La Chaux-de-Fonds, Switzerland) with that of passive ultrasonic irrigation (PUI) and conventional syringe irrigation (CSI) on the removal of triple antibiotic paste (TAP) and calcium hydroxide (Ca(OH)2) paste from root canal walls. Materials and methods: The root canals of 60 mandibular premolars with single straight oval canals were prepared using ProTaper Universal rotary instruments up to size F4 (Dentsply Maillefer, Ballaigues, Switzerland). TAP and Ca(OH)2 intracanal medications were placed inside the root canals (30 canals for each intracanal medication) and sealed with temporary filling for 3 weeks. The roots within each group were then randomly subdivided into three subgroups (n = 10) according to the irrigant activation method used to remove the intracanal medication - XP, PUI and CSI. The amount of remaining medicament was evaluated under 25× magnification using a stereomicroscope and scored in mm2 and recorded as a percentage of the overall canal surface area by using image analysis software. Statistical analysis was performed with and independent sample t-test and one-way ANOVA. The significance level was set at P ≤ 0.05. Results: None of the tested methods could completely remove either of the intracanal medications from the walls of root canals. XP and PUI removed significantly more TAP and Ca(OH)2 than CSI (P < 0.001), with no significant differences between them. Conclusions: XP and PUI were more effective in removing intracanal medications from the root canal walls than CSI. Keywords: calcium hydroxide, passive ultrasonic irrigation, regenerative endodontics, syringe irrigation, triple antibiotic paste, XP-Endo finisher files