Giorgos N. Tzanetakis

Regenerative Endodontic Therapy: A Data Analysis of Clinical Protocols

INTRODUCTION The aim of the present study was to systematically analyze the protocols that have been used in regenerative endodontic therapy and to detect any variations in clinical procedures. METHODS An electronic search was executed in PubMed using appropriate Medical Subject Heading terms covering the period from January 1993 to May 2014. Additional publications from hand searching and the reference section of each relevant article enriched the article list. The relevance of each article was initially evaluated by scanning all titles and corresponding abstracts. The definite inclusion of each article in the study was determined by using specific criteria applied independently by 3 reviewers. RESULTS Sixty relevant publications were finally included. The canal walls were not mechanically instrumented in 68% of the clinical articles. Sodium hypochlorite was included in 97% of the clinical studies either as the only irrigant or in combination with other irrigants. Antibiotic combination paste was used as the intracanal medicament in 80% of the clinical articles. Sodium hypochlorite, chlorhexidine, and EDTA were used in the final irrigation protocol in 75%, 4%, and 13% of the clinical studies, respectively. Neither the creation of a blood clot nor the use of platelet-rich plasma/platelet-rich fibrin was described in 13% of the clinical articles. Mineral trioxide aggregate was used as an intracanal coronal barrier in 85% of the relevant clinical studies. CONCLUSIONS The variability of the clinical protocols applied during regenerative enododontic procedures is considerably high. A thorough analysis of regenerative protocols may constitute an additional source to provide useful clinical considerations for REPs.

Prevalence and Management of Instrument Fracture in the Postgraduate Endodontic Program at the Dental School of Athens: A Five-year Retrospective Clinical Study

The aim of the present clinical research was to investigate the prevalence and management of instrument fracture during root canal preparation by postgraduate students (Department of Endodontics, Dental School of Athens) and to determine the percentage of referred cases with fractured instruments managed by the same students of the program. A retrospective study was conducted by reviewing the dental notes of 1367 patients (2180 endodontic cases, 4897 root canals) treated between October 2001 and June 2006 by endodontic postgraduate students at the Dental School of Athens. Type of tooth and canal, type and length of fractured segments, level of instrument fracture, and management that followed were recorded. The overall prevalence of instrument fracture during root canal preparation by postgraduate students was 1.83%. The prevalence of endodontic cases with fractured instruments referred to the endodontic postgraduates was 7.41%. The prevalence of stainless steel hand and rotary nickel-titanium instrument fracture by postgraduate students were 0.55% and 1.33%, respectively. The prevalence of instruments fractured in the apical third (52.5%) was significantly higher when compared with coronal (12.5%) and middle (27.5%) thirds of the canals. The retrieval or bypass of fractured instruments was most successful in the coronal (100%) and middle (45.4%) thirds when compared with the apical third (37.5%) of the canals. The fracture frequency was higher in retreatment cases in relation to the respective rate of initial therapies. On the basis of the results of this study, the prevalence of endodontic instrument fracture by the postgraduate students was relatively low. The prevalence of fracture of nickel-titanium rotary instruments was more frequent than that of hand instruments. Retrieval or bypass of the fractured instruments in the apical third was less successful.

A Comparative Study of the Effects of Three Root-end Filling Materials on Proliferation and Adherence of Human Periodontal Ligament Fibroblasts

INTRODUCTION The present in vitro study was conducted with the aim of evaluating and comparing the cytotoxic effects of three root-end filling materials, ProRoot mineral trioxide aggregate (ProRoot MTA; Dentsply Tulsa Dental, Memphis, TN), MTA Angelus (Angelus, Londrina, Brazil), and a modified zinc oxide-eugenol cement (Super-EBA; Bosworth Co, Skokie, IL) on human periodontal ligament (PDL) fibroblasts. METHODS PDL cells were cultured in an mineral trioxide aggregate (MTA)- or a Super-EBA-conditioned medium to assess the viability as determined by the trypan blue exclusion assay. The proliferation of the cells was recorded, and the cellular morphology was observed by confocal microscopy. Moreover, PDL cell aggregates were cultured on the substrate surfaces to assess cell adhesion. RESULTS ProRoot MTA was found to be the most biocompatible material, whereas Super-EBA was found to be the most cytotoxic material because it significantly inhibited the cell growth and adherence on its. In the presence of ProRoot MTA, the PDL cell proliferation was almost unaltered. MTA Angelus was found to be more cytotoxic than ProRoot MTA, offering, however, excellent scaffold properties for the adhesion of cell aggregates. CONCLUSIONS Under the conditions of the present study, it seems that commercially available forms of MTA may behave in different ways regarding their proliferative effect on human PDL fibroblasts. ProRoot MTA appears to be the most biocompatible of the three tested materials when considering use for root-end endodontic microsurgery.

Comparison of Bacterial Community Composition of Primary and Persistent Endodontic Infections Using Pyrosequencing

INTRODUCTION Elucidating the microbial ecology of endodontic infections (EIs) is a necessary step in developing effective intracanal antimicrobials. The aim of the present study was to investigate the bacterial composition of symptomatic and asymptomatic primary and persistent infections in a Greek population using high-throughput sequencing methods. METHODS 16S amplicon pyrosequencing of 48 root canal bacterial samples was conducted, and sequencing data were analyzed using an oral microbiome-specific and a generic (Greengenes) database. Bacterial abundance and diversity were examined by EI type (primary or persistent), and statistical analysis was performed by using non-parametric and parametric tests accounting for clustered data. RESULTS Bacteroidetes was the most abundant phylum in both infection groups. Significant, albeit weak associations of bacterial diversity were found, as measured by UniFrac distances with infection type (analyses of similarity, R = 0.087, P = .005) and symptoms (analyses of similarity, R = 0.055, P = .047). Persistent infections were significantly enriched for Proteobacteria and Tenericutes compared with primary ones; at the genus level, significant differences were noted for 14 taxa, including increased enrichment of persistent infections for Lactobacillus, Streptococcus, and Sphingomonas. More but less abundant phyla were identified using the Greengenes database; among those, Cyanobacteria (0.018%) and Acidobacteria (0.007%) were significantly enriched among persistent infections. Persistent infections showed higher phylogenetic diversity (PD) (asymptomatic: PD = 9.2, standard error [SE] = 1.3; symptomatic: PD = 8.2, SE = 0.7) compared with primary infections (asymptomatic: PD = 5.9, SE = 0.8; symptomatic: PD = 7.4, SE = 1.0). CONCLUSIONS The present study revealed a high bacterial diversity of EI and suggests that persistent infections may have more diverse bacterial communities than primary infections.

Effect of 2% Chlorhexidine Gel Mixed with Calcium Hydroxide as an Intracanal Medication on Sealing Ability of Permanent Root Canal Filling: A 6-month Follow-up

The present study was conducted to determine the influence of 2 intracanal medicaments (calcium hydroxide, chlorhexidine gel 2%) when used either alone or combined on the short- and long-term sealing ability of permanent root canal fillings. Ninety human upper central incisors were divided into 4 experimental groups (n=20). All root canals were instrumented in a step-back motion and then treated as follows: group I, root canal dressing with calcium hydroxide for 2 weeks and then obturation with laterally compacted gutta-percha and AH26 sealer; group II, chlorhexidine gel 2% for 2 weeks and obturation as in group I; group III, dressing with a new paste made by mixing calcium hydroxide plus chlorhexidine gel 2% for 2 weeks and obturation as described previously; group IV, immediately obturated with laterally compacted gutta-percha and AH26 sealer. Leakage along root canal fillings was measured using the transport fluid model. Short term measurements were carried out for 3 hours after 24 hours equilibrium establishment. Leakage was measured again at 6 months after the initial measurement. At 3 hours, no significant differences were found among the 4 experimental groups. Long-term measurements showed that also at 6 months no significant differences were observed between the group IV and the other 3 experimental groups. Under the conditions of the present study, it could be supported that none of the medications used seemed to affect negatively neither the short- nor the long-term sealing ability of the tested obturation technique. On the basis of these results and because of its increased antimicrobial action as it is supported in the literature, the new paste made of calcium hydroxide plus chlorhexidine gel 2% can be proposed for use in clinical practice without affecting the sealing ability of root canal obturation.

Combined Endodontic and Surgical Management of a Mandibular Lateral Incisor with a Rare Type of Dens Invaginatus

Dens invaginatus is a developmental malformation of teeth that most commonly affects permanent maxillary lateral incisors. Presence of dens invaginatus in mandibular permanent teeth is relatively rare. The purpose of this report is to describe the combined nonsurgical and surgical management of a mandibular lateral incisor associated with a rare type of dens invaginatus. Pulp involvement of the malformed tooth, periapical abscess, and severe periodontal destruction were observed. The signs (sinus tracts) and symptoms ceased after completion of the treatment. Satisfactory healing of the periradicular lesion was observed at the 6-month and 2-year follow-up examinations.

Impact of smear layer on sealing property of root canal obturation using 3 different techniques and sealers. Part I.

OBJECTIVE The objective of this study was to determine the influence of smear layer removal on through-and-through fluid movement along root canal fillings obturated using 3 different root canal sealers, namely AH26, Pulp Canal Sealer, and Gutta-Flow, and 3 different obturation techniques. STUDY DESIGN The fluid transport model was used for detection of through-and-through fluid movement. Root canals of 230 human extracted teeth were mechanically instrumented using the step-back technique. The canals where the smear layer was not removed were irrigated with NaOCl 2.4%, whereas canals where the smear layer was removed were irrigated with EDTA 17% plus NaOCl 2.4%. The teeth were randomly divided into 10 experimental groups (n = 20) and 3 control groups (n = 10) and treated as follows. In group A, where no attempt was made for smear layer removal, the canals were obturated with lateral compaction of gutta-percha and AH26 as a sealer. In group B, the smear layer was removed, and canals were obturated as in group A. In group C (no attempt to remove the smear layer), the canals were obturated with System B plus Obtura II technique and AH26, whereas in group D, the smear layer was removed, and canals were obturated as in group C. The other 4 experimental groups were treated and obturated in the same way as in previous groups, respectively. The sealer that was used in those groups was the Pulp Canal Sealer. Finally, the latter 2 groups were obturated with Gutta-Flow technique. Fluid movement was measured at 24 hours and 30 days and 6 months. RESULTS In lateral compaction groups (with and without the smear layer), no significant differences were found regarding the ability of the same materials (AH26 and Pulp Canal Sealer) to prevent the fluid movement (P > .05). In warm obturation technique, no significant difference was found between the 2 groups (with and without the smear layer) of AH26 (P > .05). On the contrary, in groups of Pulp Canal sealer, fluid transport values were significantly less when the smear layer was removed (P < .05). Finally, no significant difference was observed between the groups of Gutta-Flow (with and without the smear layer) (P > .05). CONCLUSIONS Under these in vitro conditions, it seems that smear layer removal improves the ability of the filling materials to prevent the fluid movement, at least after the use of warm obturation techniques. On the contrary, smear layer removal does not seem to improve the same ability after the use of cold lateral compaction technique. Further laboratory and also clinical studies are needed in the future to compose a clear view concerning the improvement of sealing ability following smear layer removal.

Non-surgical retreatment of a failed apicoectomy without retrofilling using white mineral trioxide aggregate as an apical barrier

Root-end resected teeth with persistent apical periodontitis are usually retreated surgically or a combination of non-surgical and surgical retreatment is employed. However, patients are sometimes unwilling to be subjected to a second surgical procedure. The apical barrier technique that is used for apical closure of immature teeth with necrotic pulps may be an alternative to non-surgically retreat a failed apicoectomy. Mineral trioxide aggregate (MTA) has become the material of choice in such cases because of its excellent biocompatibility, sealing ability and osseoinductive properties. This case report describes the non-surgical retreatment of a failed apicoectomy with no attempt at retrofilling of a maxillary central incisor. White MTA was used to induce apical closure of the wide resected apical area. Four-year follow-up examination revealed an asymptomatic, fully functional tooth with a satisfactory healing of the apical lesion. White MTA apical barrier may constitute a reliable and efficient technique to non-surgically retreat teeth with failed root-end resection. The predictability of such a treatment is of great benefit for the patient who is unwilling to be submitted to a second surgical procedure.

Comparison of isthmus detection methods in the apical third of mesial roots of maxillary and mandibular first molars: macroscopic observation versus operating microscope

The aims of this study were to assess the presence and the frequency of isthmuses in the mesial roots of the maxillary and mandibular first molars (at two resection levels from the apex), and to compare the findings obtained by macroscopic observation (MO) and operating microscope (OM). Forty maxillary and 40 mandibular mesial roots were observed at 3 and 5 mm from the apex initially macroscopically and then with the use of an OM. The presence of an isthmus and the number of root canals detected were recorded. Data were analyzed statistically by Fishers exact test for isthmus evaluation and Wilcoxon signed rank-test for number of root canals at a confidence interval of 95%. Comparison between MO and OM regarding the number of roots with isthmuses provided the following results: Mandibular group: At 3 mm level: MO 19 ?s. OM 27; at 5 mm level: MO 31 ?s. OM 32. Maxillary group: At 3 mm level: MO 9 ?s. OM 14; at 5 mm level: MO 19 ?s. OM 21. Significant differences (p<0.05) were found concerning the accuracy of the isthmus detection methods at both resection levels (3 and 5 mm) and both types of roots, as well as for the number of the canals inspected under the OM between the two resection levels of the mesial roots of the maxillary first molars. Under the tested conditions, OM increased the diagnostic accuracy of isthmus detection at both resection levels and root types.

Full-text publication rates of research abstracts presented at the European Society of Endodontology congresses in the last 20 years

AIM To evaluate the full-text publication rates of scientific research abstracts presented at the European Society of Endodontology (ESE) Congresses held between 1993 and 2013 (a total of 11 occasions) and to determine factors associated with the manuscripts. METHODOLOGY An electronic database search was conducted from January 2015 to December 2016 to identify full text English written publications of the research abstracts presented at the last 11 ESE Biennial Congresses from 1993 to 2013. For each occasion, research abstract information were retrieved from the International Endodontic Journal (IEJ) through the official website of the ESE and the following parameters for each abstract presentation were recorded: Year of presentation, first authors affiliation, geographic origin, and type of study. Following full-text article identification, additional information was recorded such as: Year and journal of publication, elapsed time until full publication and number of authors per presentation and publication. RESULTS A total of 1165 research abstracts were presented, of which 401 (34.4%) were finally published as full-length articles. Overall 235 articles (58.6%) were published either in the International Endodontic Journal (IEJ, 35.7%) or Journal of Endodontics (JOE, 22.9%). The mean time between abstract presentation and full-text publication was 18.95 months. Munich (2001) had the highest publication rate (44%) whereas Lisbon (2013) had the highest number of published articles (77). Turkey was the country with the highest number of published abstracts (56). However, the Netherlands was the country with the highest number of publications related to the number of presentations (21/26) (80.7%). Differences in authorship between presentation and full publication were found in 179 (44.6%) articles. CONCLUSIONS A substantial number of research abstracts presented at ESE congresses were not published in peer reviewed journals. Authors prefer to publish their research papers in international journals with high impact factor. This article is protected by copyright. All rights reserved.