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An analysis was made of the association between the endoscopic findings of the sectioned root end surface and healing of the lesion 1 year after periapical surgery, although no studies appear to have analyzed them in relation to healing after periapical surgery.A retrospective cohort study was made of patients subjected to periapical surgery between 2011 and 2019. After apicoectomy, the root end surface was examined, evaluating the number of canals, isthmuses, dentin cracks and craze lines, opaque dentin, and gaps between the filling material and the root canal wall. An analysis (using Generalized Estimating Equation models) was made of the association between the endoscopic findings and healing evaluated by von Arx and Kurt criteria and the modified PENN 3D criteria. The possible influence of patient age and gender and the type of tooth involved on healing was evaluated.A total of 108 patients (114 teeth and 128 roots) were subjected to periapical surgery. Two or more canals were detected in 27.3% of the roots (8.6% not subjected to orthograde filing), and isthmuses were identified in 18%, craze lines in 7%, cracks in 3.1%, opaque dentin in 69.5%, and gaps in 53.1% of the roots. The healing rate at 1 year according to the criteria of von Arx and Kurt was 95.4% versus 82.2% according to the modified PENN 3D criteria. Failure was more common in roots with cracks, although statistical significance was not reached (odds ratio [95% confidence interval]: 0.20 [0.01 to 4.04]; P = .200). The rest of the endoscopic findings as well as patient age and gender and the type of tooth did not influence healing (P .05).In the present sample, no statistically significant associations were observed between the endoscopic and healing at 1 year after periapical surgery. Failure was more common in roots with cracks, however.

Edentulism produces resorption of alveolar bone processes, which can complicate placement of dental implants. Guided bone regeneration techniques aim to recover the volume of bone. These treatments are susceptible to the surgical technique employed, the design of the autologous block or the tension of the suture. These factors can relate to major complications as the lack of primary closure and dehiscence. The present study, using finite element analysis, aimed to determine differences in terms of displacement of the oral mucosa, transferred stress according to Von Mises and deformation of soft tissue when two block graft designs (right-angled and rounded) and two levels of suture tension (0.05 and 0.2 N) were combined. The results showed that all the variables analyzed were greater with 0.2 N. Regarding the design of the block, no difference was found in the transferred stress and deformation of the soft tissue. However, displacement was related to a tendency to dehiscence (25% greater in the right-angled/chamfer design). In conclusion different biomechanical behavior was observed in the block graft depending on the design and suture tension, so it is recommended to use low suture tension and rounded design. A novel finite element analysis model is presented for future investigations.

A study was performed of the healing rate of teeth subjected to endodontic microsurgery after a minimum follow-up of 5 years with an analysis of the influence of different pre- and postoperative factors on the outcome.This was a retrospective study of patients subjected to endodontic microsurgery with the use of mineral trioxide aggregate (MTA) for retrograde filling between January 2011 and December 2015. In patients with multiple treated teeth, only 1 random tooth was selected for the statistical analysis. Clinical and radiographic parameters were used to assess healing. Simple binary logistic regression models were used to analyze the influence of patient age and sex, the type of tooth, prior radiographic lesion size, the presence of a post, the type of restoration, and the apical extent of prior filling of the root canal on the endodontic microsurgery success rate. Two calibrated observers evaluated the periapical radiographs on an independent basis.A total of 111 patients (63.1% women and 36.9% men) were included in the study. Of the 111 teeth analyzed, 90 were classified as healed (mean healing rate = 81.1%). Patient age and sex, the presence of a post, the type of tooth, the type of restoration, and the apical extent of prior filling of the root canal had no significant impact on the outcome. Large lesions (5 mm) were associated with a lower healing rate than smaller lesions, although the difference was not significant. Anterior teeth had a significantly higher healing rate (93.8% maxillary and 100% mandibular) than molars (70.8% maxillary and 57.1% mandibular) (P.05). The differences between the anterior teeth and the molars were statistically significant.The mean healing rate of teeth subjected to endodontic microsurgery was 81% after 5-9 years of follow-up. The success rate was lower for upper and lower molars than for teeth in the anterior zone, although the sample was small and further studies are needed to establish whether the type of tooth influences the treatment outcome.

Mechanical preparation and the formation of space for adequate obturation are included in root canal shaping, but the complex root canal anatomy may be affect it. Manufacturers have created different alloys like M-Wire, Blue-Wire, Gold-Wire or R-phase. Objective: This investigation was performed to verify the null hypothesis that there were not significant differences between size 25 instruments ESP Files Thermoflex, Protaper Ultimate, Protaper Next, Blueshaper, One Curve and 2Shape about cyclic fatigue and length of broken fragments.180 new size 25 files of the systems investigated were selected (n=30). Files were used with Endo Mate DT endo motor with speed and torque recommended by manufacturers, holding the instruments with clamping mechanism, with passive adjustment, glycerine and without pressure in a stainless-steel block. The time was calculated in seconds until fracture. Number of fatigue cycles was determined as (Resistance (s) x Speed)/60. Separated fragment lengths were calculated with digital Vernier caliper. Statistical analysis was carried out with the SPSS 18 programme at a 95% confidence level, using Levene´s Test to compare variances, Welch's Test to compare means, and Games-Howell´s Test to reveal differences between groups.Levene's Test determined no equal variances (ESP Files Thermoflex was superior in cyclic fatigue. About separated fragment lengths, ESP Files Thermoflex, Protaper Ultimate and Blueshaper obtained longer lengths.

The aim of this paper was to evaluate the intratubular penetration area of a bioceramic sealer, using continuous wave (CW), vertical condensation (VC) with two different types of gutta-percha (conventional (NG) and bioceramic-coated (BG)) and single cone (SC) technique with BG gutta-percha, in different root thirds.A total of 150 mature single-root human teeth (including incisors, canines and premolars) were prepared and randomly divided into five groups (n = 30). Teeth were filled using a bioceramic sealer (TotalFill BC Sealer HiFlow ®) and two different types of gutta-percha, with CW and VC techniques, the teeth in the control group were filled with SC technique and BG gutta-percha. The teeth were sectioned and evaluated as one-third portions in each case under a confocal laser microscope. The penetration area measurements were carried out with the Autocad ® programme. Data was analyzed using the one-factor ANOVA test (p0.05) and Post Hoc Test (p0.05).The ANOVA Test showed significant differences in the penetration areas of the five obturation techniques (P0.05). The Post Hoc Test exhibited significant differences in multiple comparisons (P0.05). There was more dentinal tubule penetration in the coronal third than in the apical third in all techniques.The intratubular penetration of the bioceramic sealer was influenced by the obturation techniques tested, but not by the different gutta-percha tested. There was more penetration of sealer in the warm obturation techniques than the SC, regardless of the type of gutta-percha used.

An apicomarginal defect can be explained as a total loss of buccal alveolus extending from the original crestal bone to the apex of the tooth. This study presents a case of an apicomarginal defect in a first left molar subjected to periapical surgery with vestibular cortex block replacement and A-PRF + membrane coating approximately one year ago. One-year clinical follow-up was performed, with no evidence of recurrence. This case report discusses periapical surgical treatment and the importance of an interdisciplinary approach to the management of teeth with apicomarginal defects. Key words:Periapical surgery, apicomarginal defect, A-PRF+, bone graft.

Although many studies have related smoking to peri-implantitis and marginal bone loss, little is known of its potential impact on dental implant osseointegration. The present clinical study explores the influence of smoking on secondary stabilization based in radiofrequency analysis. A total of 194 implants in 114 patients were included. Implant stability was evaluated on the day of surgery and at a minimum of 90 days after implantation, when osseointegration is considered to have been completed. The evolution of implant stability was compared between 2 groups: smokers and nonsmokers. The following variables were also analyzed: implant brand and model, length, diameter, insertion torque, bone density according to the Misch classification, location of the implant, and patient age and gender. The results showed that smoking did not affect the primary stability of the implant, although it was associated with a marked decrease in secondary stability. The nonsmokers showed a gain of 2.69 points (95% confidence interval [CI]: 1.529–3.865; P < .001) in the osseointegration process. However, in the smokers group, implant stability was seen to decrease 0.91 points (95% CI: −3.424 to 1.600; P < .004), generating a difference of 3.61 points between smokers and nonsmokers. Smoking is thus concluded to be an important factor that must be taken into account when seeking good implant osseointegration outcomes.

Svrha: U ovom istraživanju analizirali smo rezno područje, vrijeme instrumentacije, održavanje anatomije korijenskog kanala i neinstrumentirana područja dobivena korištenjem instrumenata F360®, Mtwo®, RaCe® i Hyflex® u ISO veličini 35. Materijali i metode: Odabrano je 120 zuba s jednim ravnim kanalom i podijeljeni su u četiri grupe. Radna duljina određena je radiološki. Zubi su rezani dijamantnim diskom, a presjeci su promatrani stereoskopskim mikroskopom Nikon SMZ-2T pod svjetiljkom Intralux 4000-1. Grupe su oblikovane predoperativnom analizom AutoCAD. Zubi su rekonstruirani s pomoću K-proširivača #10 i epoksi ljepila. Svaka grupa instrumentirana je jednim od četiriju sustava. Vrijeme instrumentacije mjereno je kronometrom s točnošću od 1/100. Područja u trećinama analizirana su za očuvanje anatomije korijena AutoCAD-om 2013., neinstrumentirana područja AutoCAD-om 2013. i stereomikroskopom SMZ-2T. Statistička analiza obavljena je Lavenovim i Bonferronijevim testom, ANOVA-om i Pearsonovim hi-kvadrat testom. Rezultati: Ista varijanca dobivena je Lavenovim testom (P > 0,05). ANOVA (P > 0,05) nije zabilježila značajne razlike. Značajna razlika bila je u vremenu instrumentacije (p < 0,05). U očuvanju anatomije korijenskog kanala i u neinstrumentiranim područjima nije bilo značajne razlike među sustavima (P > 0,05). Zaključci: Uporabom svih četiriju različitih rotacijskih sustava dobivena su slična rezna područja, a sačuvana je bila i anatomija korijenskih kanala i neinstrumentiranih područja. U određivanju vremena instrumentacije statistički je bio najbrži sustav F360® ., Purpose: This study compared the cutting area, instrumentation time, root canal anatomy preservation and non-instrumented areas obtained by F360®, Mtwo®, RaCe® and Hyflex® files with ISO size 35. Material and Methods: 120 teeth with a single straight root and root canal were divided into 4 groups. Working length was calculated by using X-rays. The teeth were sectioned with a handpiece and a diamond disc, and the sections were observed with Nikon SMZ-2T stereoscopic microscope and an Intralux 4000-1 light source. The groups were adjusted with a preoperative analysis with AutoCAD. The teeth were reconstructed by a #10 K-File and epoxy glue. Each group was instrumented with one of the four file systems. The instrumentation time was calculated with a 1/100 second chronometer. The area of the thirds and root canal anatomy preservation were analyzed with AutoCAD 2013 and the non-instrumented areas with AutoCAD 2013 and SMZ-2T stereoscopic microscope. The statistical analysis was made with Levene’s Test, ANOVA, Bonferroni Test and Pearson´s Chi-square. Results: Equal variances were shown by Levene’s Test (P > 0.05). ANOVA (P > 0.05) showed the absence of significant differences. There were significant ifferences in the instrumentation time (P < 0.05). For root canal anatomy preservation and non-instrumented areas, there were no significant differences between all systems (P > 0.05). Conclusions: The 4 different rotary systems produced similar cutting area, root canal anatomy preservation and non-instrumented areas. Regarding instrumentation time, F360® was the fastest system statistically.

9 páginas, 1 tabla, 13 esquemas., 5-Methylenehydantoin, as well as the N-mono- and N,N-di-protected derivatives, can be obtained by different synthetic routes. These compounds can undergo a large variety of reactions, such as Diels–Alder, epoxidation, methanol addition and conjugate addition reactions of different types of nucleophiles, including carbon (cyanide), nitrogen (piperidine) and sulfur (thiols, thioacetate) nucleophiles. The reactivity with electrophilic reagents, such as m-CPBA or methanol in acidic medium, and the need for Lewis acids to promote the conjugate addition reactions indicate that hydantoin is a poor electron-withdrawing group., This work was made possible by the generous financial support of Deretil, and the Spanish ‘Ministerio de Ciencia e Innovaci on’ (CTQ2008-05138 and Consolider Ingenio 2010 INTECAT CSD2006- 0003).

Objectives. To compare the effectiveness of four instrument systems for preparing oval root canals: manual instrumentation (Step-Back technique), ProTaper Universal, ProTaper Next, and Wave One.Material and Methods. For the purpose of this assessment, 60 teeth extracted for orthodontic or periodontal reasons, specifically canines and premolars with full coronal and root anatomy, were used and 15 samples were assigned to each group. The section of the canals was compared before and after instrumenting and the section of untouched canal wall was measured using AutoCAD software. The data was analysed by means of Shapiro-Wilk, ANOVA, and Kruskal-Wallis tests.Results. In the apical third, 100% of the canals were prepared with all the systems. In the middle third, apvalue of 0.5989 in the Kruskal-Wallis test was obtained, which indicates no significant difference between the groups. At the coronal third level, the results obtained revealed that Wave One had a significantly lower mean average than the rest (p<0.05).Conclusions. There are no differences between the various root canal instrument systems in the apical and middle thirds. At the coronal third level, Wave One system showed performance significantly worse than the rest, among which there were no differences.

The sulfonic acid resin Dowex ® 50W × 8 can be used to replace mineral acids in the reaction between p -hydroxymandelic acid and urea in water or NaCl solutions. The synthesis of p -hydroxymandelic acid is efficiently carried out using NaOH to promote the reaction between phenol and glyoxylic acid. Alternatively, KF/alumina can be used to obtain methyl p -hydroxymandelate by reaction of phenol with methyl 2-hydroxy-2-methoxyacetate, although, this process is carried out in an organic solvent and gives a lower yield. A comparison between the three alternative methods for the synthesis of 5-(4-hydroxyphenyl)hydantoin shows that the direct route from glyoxylic acid, urea and phenol is the most efficient method, although the p -hydroxymandelic acid route would be an interesting alternative if its heterogeneous synthesis were optimized.

Different Lewis acids are able to promote the Friedel–Crafts reaction between 5-bromohydantoin and aromatic compounds. In the case of phenol, mixtures of ortho and para isomers are always obtained, with Mg(ClO 4 ) 2 leading to the best selectivity. However, the best overall yield of 5-(hydroxyphenyl)hydantoin is obtained with YbCl 3 . This method can be extended to other aromatic systems such as anisole and thiophene. These reactions give similar yields but proceed with total selectivity to 5-(4-methoxyphenyl)hydantoin and 5-(2-thiophenyl)hydantoin, respectively. The cationic exchange of Mg II and Yb III on anionic solid supports allows the preparation of very efficient heterogeneous catalysts for this reaction (productivity up to 600 mol of hydantoin per mole of Mg). These catalysts have practical advantages in that they can be recycled and reused.

Clays, zeolites and organic polymers bearing sulfonic acid groups are used to promote the direct synthesis of dl-5-(4-hydroxyphenyl)hydantoin from urea, phenol and glyoxylic acid. Only organic polymers lead to good results, in particular a sulfonic polystyrene-divinylbenzene resin with a small particle size, whereas very poor results are obtained when clays or zeolites are used to promote this amidoalkylation reaction. A possible explanation for these rather surprising differences in behavior involves the different hydrophilic/hydrophobic character of the solids, particularly given the aqueous reaction medium. The pre-treatment of the resin and the particle size are important factors that influence the final result. Although the results are no better than those obtained with hydrochloric acid in the homogeneous phase, these resins do represent the only environmentally friendly alternative., We are indebted to DSM Deretil for financial support and providing some of the reagents and products.

The synthesis of allantoin from glyoxylic acid and urea has been studied using several heterogeneous catalysts. Organic resins and nanocomposites, particularly sulfonic resins, lead to higher yields than zeolites. Polymer morphology has a significant influence on the performance of the catalyst. The possibility of using the same type of solid acid in the reaction of allantoin with phenol has also been explored. However, this route requires a larger amount of acid and leads to lower para/ortho selectivity than the direct route from glyoxylic acid and urea., We are indebted to Dr. Mark A. Harmer, from DuPont Research and Development, for the generous gift of SAC-13. The financial support of DSM Deretil and the Spanish M.C.Y.T. (project PPQ2000-0322-P4) are acknowledged.

5-Methylenehydantoin, as well as the N-mono- and N,N-di-protected derivatives, can be obtained by different synthetic routes. These compounds can undergo a large variety of reactions, such as Diels–Alder, epoxidation, methanol addition and conjugate addition reactions of different types of nucleophiles, including carbon (cyanide), nitrogen (piperidine) and sulfur (thiols, thioacetate) nucleophiles. The reactivity with electrophilic reagents, such as m-CPBA or methanol in acidic medium, and the need for Lewis acids to promote the conjugate addition reactions indicate that hydantoin is a poor electron-withdrawing group.

Two different electronic apex locators were used before extraction to determine working length in 116 root canals belonging to 34 molars. The results were then compared with postextraction working length measurements. The determinations were made before and after eliminating the canal contents and drying the interior. The results showed that 84.8% and 79.3% of the Odometer, and 89.6% and 88.7% of the Endocater readings for dry and nondry canals, respectively, occurred within the two 0.5-mm intervals closest to the apical constriction.

PURPOSE. The aim of this study was to compare the radiopacity of 6 modern resin cements with that of human enamel and dentine using the Digora digital radiography system, to verify whether they meet the requirements of ANSI/ADA specification no. 27/1993 and the ISO 4049/2000 standard and assess whether their radiopacity is influenced by the thickness of the cement employed. MATERIALS AND METHODS. Three 3-thickness samples (0.5, 1 and 1.5 mm) were fabricated for each material. The individual cement samples were radiographed on the CCD sensor next to the aluminium wedge and the tooth samples. Five radiographs were made of each sample and therefore five readings of radiographic density were taken for each thickness of the materials. The radiopacity was measured in pixels using Digora 2.6 software. The calibration curve obtained from the mean values of each step of the wedge made it possible to obtain the equivalent in mm of aluminium for each mm of the luting material. RESULTS. With the exception of Variolink Veneer Medium Value 0, all the cements studied were more radiopaque than enamel and dentin (P

Objetivo: evaluar la compatibilidad dimensional entre los conos de gutapercha y los espaciadores. Material y metodo: se seleccionaron aleatoriamente conos de gutapercha y espaciadores de diferentes tamanos y fabricantes (Dentsply-DeTrey, DEntsply-Maillefer y Boston Dental Scientific). Se conformaron 26 grupos (n: 10). Cada una de las muestras se observo con un microscopio optico (50-100x), y se midio D1 y D2. Los resultados se sometieron a un analisis estadistico descriptivo. Resultados: de acuerdo con nuestro datos, existe variabilidad dimensional entre los conos de gutapercha de un mismo tamano, los espaciadores y las puntas de gutapercha y los espaciadores entre si, aunque las diferencias entre este ultimo grupo son menores. Conclusion: existen discrepancias dimensionales entre los conos de gutapercha y los espaciadores, las cuales podrian causar inconvenientes durante la obturacion tridimensional del sistema de conductos radiculares y propiciar uns ellado apical incorrecto. Palabras clave: obturacion de conductos, espaciadores, gutapercha, instrumentos endodoncicos.

A comparison was made of the ability of two root canal obturating techniques to prevent dye microleakage: gutta-percha lateral condensation and mechanically plasticized gutta-percha (JS Quick-fill). Twenty central incisors were prepared and obturated by each technique. After rendering the teeth transparent, linear dye penetration was found to be 0.48 and 0.52 mm, respectively. The difference between the two techniques was not significant. As for the distribution of the sealing cement (AH26) in the teeth obturated with JS Quickfill, the cement was located in the most peripheral zone of the obturation alongside the dentinal walls, whereas the gutta-percha was found in the central part of the canal obturating material.