Healing of apical periodontitis after endodontic treatment: a comparison between a silicone-based and a zinc oxide-eugenol-based sealer

Biological properties versus solubility of endodontic sealers and cements

Endodontic sealers and cements used in root canal treatment have different compositions and properties. Common to all materials is that their primary goal is to fill gaps and voids, making a permanent seal of the root canal system. Furthermore, aspects such as antibacterial properties, cytotoxicity, setting time, solubility and biocompatibility are also crucial and ought to be considered. Over the years, a shift in the view on the importance of these aspects has ocurred. Whereas the antibacterial properties were considered important when the technical factors in endodontics were less developed, the sealing ability and biocompatibility have later been considered the most critical factors. The introduction of tricalcium silicate cements and sealers has led to a renewed interest in material properties, as these cements seem to have good sealing ability and at the same time combine favourable antimicrobial effects with excellent biocompatibility. This review discusses how the various properties of root canal sealers and cements may conflict with the primary aim of providing a permanent seal of the root canal system.

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.

Influence of sealer type on treatment outcome of teeth with apical periodontitis: a systematic review

BACKGROUND

The purpose of this article was to Evaluate the influence of sealer on the outcome of non-surgical endodontic treatment or retreatment of permanent teeth with apical periodontitis (PROSPERO registration: CRD42020205951).

METHODOLOGY

A systematic review of original clinical studies was carried out following PRISMA guidelines to answer whether the type of sealer used in endodontic treatment or retreatment influences the repair of apical periodontitis determined by clinical and radiographic parameters. Electronic searches were performed in PubMed, Embase, Web of Science, Scopus, and the Cochrane Library database, until May 2023. Gray literature and a hand search of reference lists were also performed. The risk of bias was assessed using Cochrane RoB2 for randomized trials and the Newcastle-Ottawa Scale (NOS) for prospective and retrospective cohort and case-control studies.

RESULTS

Among 1046 studies, a total of 819 were selected by title and abstract, resulting in 23 for full-text review. In total, 11 studies met the inclusion criteria (1467 patients/teeth with apical periodontitis). The quality assessment using RoB2 included five randomized control trials, of which four had medium risk and one had a low risk of bias. According to the NOS scale, five studies were classified as low risk and one study was considered as medium risk of bias. The sealer type and obturation techniques varied, and the mean follow-up time was 3.7 years. Most studies used two-dimensional radiographic criteria to assess the treatment outcome sealers and not cements. Eight studies did not find significant differences when comparing cements. The healing rates ranged from 56.7% to 90%.

CONCLUSIONS

The results of this review support that the current endodontic sealers do not seem to influence the treatment outcome of permanent teeth with apical periodontitis. Although the studies had medium and low risk of bias, the results should be interpreted with caution. More randomized studies of long-term outcomes comparing filling materials are needed to strengthen this claim and allow for a meta-analysis.

Factors that affect the outcomes of root canal treatment and retreatment-A reframing of the principles

This paper undertakes a broad and comprehensive synthesis of relevant clinical, biological, biomechanical, technical and healthcare services data to understand the factors affecting outcomes of periapical healing after root canal (re)treatment. The medical and dental evidence-based era (1980-present) is contextualized with the earlier evidence drive in endodontics (1911-1940) triggered by the focal infection era. The current evidence-based approach has a sharper focus on evidence quality and derivation of practice guidelines. Contrary views question whether guideline-driven, or expertise-development-driven endeavours would best serve outcome improvement in society. The endodontic discipline functions in a broad healthcare framework and sustains industrial, economic and trend pressures that may be deemed to influence outcomes. The nature of root canal treatment and the challenges in determining the factors that affect its outcomes is discussed. The factors potentially affecting periapical healing after root canal treatment are classified into pre-operative, intra-operative and postoperative groups. These categories subsume multiple elements with interactive influences, creating a complex picture, further confounded by some apparently surprising, counter-intuitive and contradictory findings. The technical versus biological conundrum in root canal treatment continues to cause cognitive dissonance. However, due reflection and cross-discipline-synthesis resolve the apparent data conflicts into a very simple, consistent and plausible picture of how root canal treatment works and the key factors that affect periapical healing. Root canal retreatment is considered mainly in the context of its differences from primary treatment as the majority of factors influencing outcomes are common to both. The exceptional difference is that retreatments have a proportionately reduced probability of healing by virtue of compromised apical root canal ramification access or modified host/infection interactions. Root canal (re)treatment outcomes are dominantly influenced by the nature of prior dynamic host/infection interaction (pre-operative patient factors) and how the direction of this dynamic is influenced by two factors: (1) the active efficacy of the operators' root canal treatment protocol to sustain a microbial ecological shift (intra-operative treatment factors) and dampen periapical inflammation; and (2) the passive ability of the functional tooth (and its restoration margin) to maintain its integrity to resist infection reversal (postoperative restorative factors).

Outcomes of root canal treatment of first permanent molars among children in Jeddah, Saudi Arabia: A retrospective cohort study

Objectives

The first permanent molar (FPM) is considered the tooth most susceptible to caries, as it is the first permanent tooth to erupt in the oral cavity, making it susceptible to environmental conditions that may appear as caries, hypoplasia, or hypomineralization. Several treatment options are available for managing deep caries, including root canal treatment (RCT). However, there is a lack of data on the success and failure rates of RCT in FPM among children. This study aimed to determine the success and failure rates of RCT in FPM among children and related factors.

Methods

This retrospective cohort study was conducted at three major centers in Jeddah, Saudi Arabia. Children aged 9–18 years who underwent an RCT between 2010 and 2019 were included. Clinical and radiographic examinations were also performed.

Results

Based on the loose criteria, most of the evaluated teeth (79.6%) were successfully treated. The treatment failed in only 20.4% of participants. Older patients and teeth with acceptable restoration quality had an increased success rate compared to younger patients and teeth with unacceptable restoration quality. A shorter time lapse between treatment and assessment resulted in a lower success rate compared to a longer time lapse. Based on strict criteria, 72.9% of the patients were successfully treated. The use of a microscope and teeth with acceptable restoration quality resulted in an increased success rate compared to teeth treated without the microscope and with unacceptable restoration quality.

Conclusions

The success rate of this procedure was high. Several factors, including older age, acceptable restoration quality, and the use of a microscope, increase the probability of success.

Periapical Healing following Root Canal Treatment Using Different Endodontic Sealers: A Systematic Review

The healing of the periapical tissues is crucial to the success of root canal treatment. The review studies effectively examine various endodontic root canal sealants in terms of periapical healing. This systematic review was formulated following the PRISMA 2020 guidelines and registered in the international prospective register of systematic reviews (PROSPERO) number-CRD42021239192. To find relevant articles, PubMed Central and Medline databases (until February 2022) were searched. Studies that evaluated healing following the application of different endodontic sealers were analysed. A primary outcome measure was the resolution of periapical lesions following the endodontic treatment. In vivo studies comparing radiographic treatment outcomes and articles with a minimum of 6-month follow-up were included. A total of 9 clinical trial studies that met all the inclusion criteria were included in the analysis. The overall risk of bias was high in four studies out of nine studies. Periapical lesions showed significant healing after endodontic treatment regardless of sealer type, although bioceramic and bioactive sealers had shown better results.

Outcomes of Primary Root Canal Therapy: An updated Systematic Review of Longitudinal Clinical Studies Published between 2003 and 2020

Background

A comprehensive effort to evaluate outcomes of primary root canal therapy (RCT) between 1966 and 2002 was published by Ng et al. (2007, International Endodontic Journal, 40, 921; 2008, International Endodontic Journal, 41, 6). Changes in endodontic materials and treatment methods warrant an updated analysis of outcomes.

Objectives

This study aimed to (1) quantify the success rates of primary RCT published between 2003 and 2020; and (2) investigate the influence of some characteristics known/suspected to be associated with treatment outcomes.

Methods

An electronic search was performed in the following databases (01‐01‐2003 to 12‐31‐2020): Pubmed, Embase, CINHAL, Cochrane and Web of Science. Included study designs were longitudinal clinical studies (randomized control trials, cohort studies, retrospective observational studies). Studies with at least twelve‐months of post‐operative review and success rates based on clinical and radiographic criteria were analysed. The terms ‘strict’ (complete resolution of periapical lesion) or ‘loose’ (reduction in size of existing periapical lesion) were used to describe the outcome criteria. Weighted, pooled success rates were calculated. Random effects meta‐regression models were used to investigate potential sources of statistical heterogeneity. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to evaluate for quality assessment of the included studies.

Results

Forty‐two studies were included in the review. Meta‐analyses showed that the weighted pooled success rates were estimated to be 92.6% (95% CI: 90.5%–94.8%) under ‘loose criteria’ and 82.0% (95% CI: 79.3%–84.8%) under ‘strict’ criteria. The most significant areas of study heterogeneity were year of publication and qualification of operator. The majority (64.29%) of studies were considered to be of low quality of evidence.

Discussion

Biological factors continue to have the most significant impact on RCT outcomes. The technological method of instrumentation had no significant effect. The quality of evidence was based primarily on study design and only randomized control trials were considered to be ‘high’ quality of evidence.

Conclusions

The reported success rates show improvement over time. Weighted success rates for studies with a minimum of four‐years follow‐up had better outcomes, compared to those with less than four years, when ‘strict criteria’ were used.

Registration

PROSPERO database (CRD42021226311).

Endodontic procedures for retreatment of periapical lesions

BACKGROUND

When primary root canal therapy fails, periapical lesions can be retreated with or without surgery. Root canal retreatment is a non-surgical procedure that involves removal of root canal filling materials from the tooth, followed by cleaning, shaping and obturating of the canals. Root-end resection is a surgical procedure that involves exposure of the periapical lesion through an osteotomy, surgical removal of the lesion, removal of part of the root-end tip, disinfection and, commonly, retrograde sealing or filling of the apical portion of the remaining root canal. This review updates one published in 2008.

OBJECTIVES

To assess effects of surgical and non-surgical therapy for retreatment of teeth with apical periodontitis.To assess effects of surgical root-end resection under various conditions, for example, when different materials, devices or techniques are used.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Trials Register (to 10 February 2016), the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1), MEDLINE Ovid (1946 to 10 February 2016) and Embase Ovid (1980 to 10 February 2016). We searched the US National Registry of Clinical Trials (ClinicalTrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform for ongoing trials (to 10 February 2016). We placed no restrictions regarding language and publication date. We handsearched the reference lists of the studies retrieved and key journals in the field of endodontics.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) involving people with periapical pathosis. Studies could compare surgery versus non-surgical treatment or could compare different types of surgery. Outcome measures were healing of the periapical lesion assessed after one-year follow-up or longer; postoperative pain and discomfort; and adverse effects such as tooth loss, mobility, soft tissue recession, abscess, infection, neurological damage or loss of root sealing material evaluated through radiographs.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from included studies and assessed their risk of bias. We contacted study authors to obtain missing information. We combined results of trials assessing comparable outcomes using the fixed-effect model, with risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, and 95% confidence intervals (CIs). We used generic inverse variance for split-mouth studies.

MAIN RESULTS

We included 20 RCTs. Two trials at high risk of bias assessed surgery versus a non-surgical approach: root-end resection with root-end filling versus root canal retreatment. The other 18 trials evaluated different surgical protocols: cone beam computed tomography (CBCT) versus periapical radiography for preoperative assessment (one study at high risk of bias); antibiotic prophylaxis versus placebo (one study at unclear risk); different magnification devices (loupes, surgical microscope, endoscope) (two studies at high risk); types of incision (papilla base incision, sulcular incision) (one study at high risk and one at unclear risk); ultrasonic devices versus handpiece burs (one study at high risk); types of root-end filling material (glass ionomer cement, amalgam, intermediate restorative material (IRM), mineral trioxide aggregate (MTA), gutta-percha (GP), super-ethoxy benzoic acid (EBA)) (five studies at high risk of bias, one at unclear risk and one at low risk); grafting versus no grafting (three studies at high risk and one at unclear risk); and low energy level laser therapy versus placebo (irradiation without laser activation) versus control (no use of the laser device) (one study at high risk).There was no clear evidence of superiority of the surgical or non-surgical approach for healing at one-year follow-up (RR 1.15, 95% CI 0.97 to 1.35; two RCTs, 126 participants) or at four- or 10-year follow-up (one RCT, 82 to 95 participants), although the evidence is very low quality. More participants in the surgically treated group reported pain in the first week after treatment (RR 3.34, 95% CI 2.05 to 5.43; one RCT, 87 participants; low quality evidence).In terms of surgical protocols, there was some inconclusive evidence that ultrasonic devices for root-end preparation may improve healing one year after retreatment, when compared with the traditional bur (RR 1.14, 95% CI 1.00 to 1.30; one RCT, 290 participants; low quality evidence).There was evidence of better healing when root-ends were filled with MTA than when they were treated by smoothing of orthograde GP root filling, after one-year follow-up (RR 1.60, 95% CI 1.14 to 2.24; one RCT, 46 participants; low quality evidence).There was no evidence that using CBCT rather than radiography for preoperative evaluation was advantageous for healing (RR 1.02, 95% CI 0.70 to 1.47; one RCT, 39 participants; very low quality evidence), nor that any magnification device affected healing more than any other (loupes versus endoscope at one year: RR 1.05, 95% CI 0.92 to 1.20; microscope versus endoscope at two years: RR 1.01, 95% CI 0.89 to 1.15; one RCT, 70 participants, low quality evidence).There was no evidence that antibiotic prophylaxis reduced incidence of postoperative infection (RR 0.49, 95% CI 0.09 to 2.64; one RCT, 250 participants; low quality evidence).There was some evidence that using a papilla base incision (PBI) may be beneficial for preservation of the interdental papilla compared with complete papilla mobilisation (one RCT (split-mouth), 12 participants/24 sites; very low quality evidence). There was no evidence of less pain in the PBI group at day 1 post surgery (one RCT, 38 participants; very low quality evidence).There was evidence that adjunctive use of a gel of plasma rich in growth factors reduced postoperative pain compared with no grafting (measured on visual analogue scale: one day postoperative MD -51.60 mm, 95% CI -63.43 to -39.77; one RCT, 36 participants; low quality evidence).There was no evidence that use of low energy level laser therapy (LLLT) prevented postoperative pain (very low quality evidence).

AUTHORS' CONCLUSIONS

Available evidence does not provide clinicians with reliable guidelines for treating periapical lesions. Further research is necessary to understand the effects of surgical versus non-surgical approaches, and to determine which surgical procedures provide the best results for periapical lesion healing and postoperative quality of life. Future studies should use standardised techniques and success criteria, precisely defined outcomes and the participant as the unit of analysis.

Apically Extruded Sealers: Fate and Influence on Treatment Outcome

INTRODUCTION

This retrospective study evaluated cases of unintentional overfillings for the fate of the extruded sealers and their influence on treatment outcome.

METHODS

One hundred five teeth treated by a single operator and exhibiting overfillings in the postobturation radiograph were included in the study. Seventy-five teeth exhibited apical periodontitis lesions at the time of treatment. Sealers included Pulp Canal Sealer (Sybron Dental, Orange, CA), PCS Extended Working Time-EWT (Sybron Dental), Tubli-Seal (Sybron Endo), Endomethasone (Septodont, Saint-Maur-des-Fossés, France), AH Plus (DeTrey GmbH, Konstanz, Germany), and Apexit (Ivoclar Vivadent, Schaan, Lichtenstein). Recall radiographs were compared with immediate postobturation films for removal of the extruded material and status of the periradicular tissues. Data were grouped as 1-, 2- and >4-year recall and statistically analyzed using the chi-square and Fisher exact tests.

RESULTS

As for the sealers' fate, the only statistically significant differences at the 1-year recall were observed when comparing Tubli-Seal with AH Plus, Apexit, and Endomethasone (P < .05). At both the 2- and 4-year recalls, frequency of complete removal of AH Plus and Apexit was significantly lower when compared with all the other sealers (P < .05). No other significant differences were observed between groups. As for the influence on treatment outcome, there were no statistically significant differences between sealers at all follow-up periods (P > .05). Data from the >4-year recall revealed that 79% of the teeth with apical periodontitis lesions at the time of treatment had healed in comparison with 100% of the teeth with no apical periodontitis (P < .01).

CONCLUSIONS

Not all extruded sealers were predictably removed from the periradicular tissues. Treatment outcome was not significantly affected by the type of extruded sealer. A significantly better outcome was observed for teeth with no lesion in comparison with teeth with apical periodontitis.

Clinical and radiographic evaluation of a resin-based root canal sealer: an eight-year update

INTRODUCTION

This retrospective clinical and radiographic study evaluated the 8-year outcome of one-visit endodontic treatment of root canals filled with gutta-percha and a methacrylate resin-based sealer (EndoREZ).

METHODS

From an initial sample size of 180 patients, subsequently 145 and 120 patients were evaluated after 14-18 months and 5 years, respectively. Of the remaining patient pool of 120 patients evaluated after 5 years, 112 patients with 212 root canals responded to the 8-year recall. The outcome of treatments was assessed on the basis of clinical and radiographic criteria. Endodontic success was rated on the basis of absence of clinical symptoms, the presence of a normal or slightly widened periodontal ligament space, and absence or substantial reduction in size of preexisting periradicular radiolucencies. Teeth that did not meet these criteria were considered endodontic failures.

RESULTS

The root canals had been adequately filled to the working length in 90 teeth (80.35%) and were short in 19 instances (16.96%). None of the roots showing apical extrusion of the sealer immediately postoperatively had radiographic evidence of the sealer in the periradicular tissues after 8 years. At recall, all patients were comfortable and free of clinical symptoms. A life table analysis showed a cumulative probability of success of 86.5% after 8 years, with a 95% confidence interval of 79.0-92.0.

CONCLUSIONS

The results of this retrospective clinical and radiographic study suggest that the tested methacrylate resin-based sealer used in conjunction with gutta-percha cones performed similarly to conventional endodontic sealers during a period of up to 8 years.

Resin materials for root canal obturation

With the appearance of more in vivo and ex vivo publications, methacrylate based resin sealers are becoming more popular in endodontics. Their ease of use and favorable clinical performance offer an attractive alternative to conventional endodontics. This article reviews the development of resin-based sealers and biocompatibility tests. The many, mostly opposing views are analyzed to put what has been published thus far in perspective. A critical analysis of the facts leads to the consensus that methacrylate based resin sealers are here to stay and offer a suitable alternative to conventional endodontic treatment.

Periapical repair after root canal filling with different root canal sealers

The aim of this study was to evaluate periapical repair after root canal filling with different endodontic sealers. Sixty-four root canals from dog´s teeth were filled, divided into 4 groups (n=16). Root canals were instrumented with K-type files and irrigated with 1% sodium hypochlorite solution. Root canals were filled in the same session by active lateral condensation of the cones and sealers: Intrafill, AH Plus, Roeko Seal and Resilon/Epiphany System. After 90 days, the animals were euthanized and the tissues to be evaluated were processed and stained with hematoxylin and eosin. For histopathological analysis, the following parameters were evaluated: inflammatory process, mineralized tissue resorption, and apical mineralized tissue deposition. Histopathological analysis demonstrated that Intrafill had less favorable results in terms of apical and periapical repair, compared to the other sealers (p<0.05). AH Plus, Roeko Seal, and Epiphany sealers had similar and satisfactory results (p>0.05). In conclusion, AH Plus and the materials Roeko Seal and Epiphany are good options for clinical use in Endodontics.

Treatment outcome in endodontics: the Toronto study--phase 4: initial treatment

Outcome 4-6 years after initial treatment was assessed for Phase 4 (2000-2001) of the Toronto Study. Of 582 teeth treated, 430 were lost to follow-up (99 discontinuers, 331 dropouts), 15 were extracted, and 137 (32% recall minus 15 extracted teeth) were examined for outcome: healed (no apical periodontitis, signs, symptoms) or diseased. When pooled with Phases 1-3, 439 of 510 teeth (86%) were healed. Logistic regression identified 2 significant (P < or = .05) preoperative outcome predictors: radiolucency (odds ratio [OR], 2.86; confidence interval [CI], 1.56-5.24; healed: absent, 93%; present, 82%) and number of roots (OR, 2.53; CI, 1.25-5.13; healed: single, 93%; multiple, 84%). In teeth with radiolucency, intraoperative complications (OR, 2.27; CI, 1.05-4.89; healed: absent, 84%; present, 69%) and root-filling technique (OR, 1.89; CI, 1.01-3.53; healed: lateral, 77%; vertical, 87%) were additional outcome predictors. A better outcome was suggested for teeth without radiolucency, with single roots, and without mid-treatment complications. The predictive value of root-filling technique in teeth with radiolucency requires validation from randomized controlled trials.

The sealing ability of GuttaFlow in oval-shaped canals: an ex vivo study using a polymicrobial leakage model

AIM

To compare systematically the sealing ability provided by four endodontic cements: AH Plus, Pulp Canal Sealer EWT, RoekoSeal and GuttaFlow.

METHODOLOGY

A sample of 100 human mandibular incisors with oval-shaped canals was selected from an initial sampling of two hundred teeth. The root canals in 80 teeth were prepared and filled by the same operator using the cold lateral compaction technique with one of the following four cements (n = 20): G1: AH Plus; G2: Pulp Canal Sealer EWT; G3: RoekoSeal and G4: GuttaFlow. Ten teeth with intact crowns served as negative controls and 10 teeth that were not root filled served as positive controls. All teeth were mounted in a two chamber apparatus and then exposed to human saliva. The number of days over a 9-weeks-period was recorded for the appearance of turbidity in the BHI broth. A Log-rank test was used to analyse the leakage data.

RESULTS

Overall, 30% of the samples of the AH Plus group (G1) and 35% of the Pulp Canal Sealer EWT group (G2) were fully contaminated after 9 weeks, whereas 15% of RoekoSeal (G3) and GuttaFlow (G4) groups were fully contaminated. There was a significant difference between (G1/G2) and (G3/G4) (P < 0.05). There was no significant difference between G1 and G2 or between G3 and G4 (P > 0.05).

CONCLUSION

The silicone-based sealers revealed the best results throughout the experimental period. Leakage patterns of AH plus and Pulp Canal Sealer were statistically similar.

Clinical and Radiographical Evaluation of a Resin-based Root Canal Sealer: A 5-Year Follow-up

A retrospective clinical and radiographical analysis of 5-year postendodontic treatment with a resin-based sealer (EndoRez; Ultradent Products Inc, South Jordan, UT) and gutta-percha was conducted. The results after 14 to 24 months were reported previously. Of 180 patients, 120 responded to the 5-year recall. Success of root canal treatments was based on absence of clinical symptoms, a normal or slightly widened periodontal ligament, and absence or reduction of periapical radiolucencies in patients who had preexisting lesions. Root canals had been adequately filled to the working length in 92 teeth (76.66%) and short in 13 (10.83%). Fifteen cases (12.50%), filled flush at the initiation of the experiment, showed slight resorption of the filling material at the apex within the lumen of the root canal. Of the 10 roots with extrusion, none had radiographic evidence of sealer in the periradicular tissues after 5 years. All patients were free of clinical symptoms. Four cases (3.3%) showed partial healing, whereas 8 cases (6.66%) were judged failures. A life table analysis revealed a cumulative probability of success of 86.3% at the 5-year recall with a 95% confidence interval of 79.7 to 91.0. The clinical and radiographical data suggest that the tested resin-based sealer used in conjunction with gutta-percha performed very well as a root canal sealer over a period of up to 5 years.

Cytotoxicity of new resin-, calcium hydroxide- and silicone-based root canal sealers on fibroblasts derived from human gingiva and L929 cell lines

AIM

To assess ex vivo the cytotoxic effects of five new root canal sealers (RC Sealer, Epiphany, EndoREZ, GuttaFlow and Acroseal) and three existing products (AH Plus, RoekoSeal and Apexit) using primary human gingival fibroblasts (HGF) and a mouse fibroblast cell line, L929.

METHODOLOGY

Eight samples of each sealer were fabricated in sterile cylindrical Teflon blocks, 4.4 mm diameter and 2 mm height and then divided into two groups, fresh and aged specimens. Extraction of fresh specimens was carried out after setting whilst aged specimens were placed in Petri dishes and kept in a humid chamber at 37 degrees C for 7 days before extraction in cell culture medium using the ratio 1.25 cm(2) mL(-1). Undiluted eluates were used for the dimethylthiazol diphenyltetrazolium bromide (MTT) assay with HGF and L-929. Morphology of HGF cells was also examined by an inverted microscope using undiluted eluates of the sealers. The results were analysed using a two-tailed t-test (alpha = 0.05) between groups.

RESULTS

Resin-based (Epiphany and EndoREZ) and calcium hydroxide-based (Apexit and Acroseal) sealers were significantly more cytotoxic than other sealers (P<0.05). However, L929 cells were more sensitive to Apexit and EndoREZ than HGF cells. RC Sealer showed mild cytotoxicity to HGF at both setting times. AH Plus did not exert any cytotoxic effect to HGF and aged specimens appeared to induce cellular proliferation. RoekoSeal and GuttaFlow also demonstrated mild cytotoxicity. GuttaFlow was slightly more cytotoxic to both cultures, especially when tested fresh.

CONCLUSIONS

Toxicity varied but RC Sealer and GuttaFlow were the least toxic new sealers.

The Influence of Root Canal Sealer on Extended Intracanal Survival of Enterococcus faecalis With and Without Gelatinase Production Ability in Obturated Root Canals

Enterococcus faecalis can survive for extended periods in obturated root canals. In this study, the hypotheses tested were that long-term survival of E. faecalis is dependent on (1) the type of endodontic sealer and (2) the capacity for microbial gelatinase activity, a potential "virulence" trait identified previously in clinical isolates. Root canals of extracted human canines (n=95) were inoculated with either E. faecalis OG1RF or its gelatinase-negative mutant E. faecalis TX5128. After 48 hours of incubation at 37 degrees C, canals were obturated with gutta-percha and either the epoxy-resin-based AH-Plus (Dentsply, De Trey, Konstanz, Germany), the silicone-based RoekoSeal (Coltène/Whaledent, Langenau, Germany), or zinc oxide eugenol-based Roth's sealer (Root Canal Cement Type 801; Roth International Ltd, Chicago, IL). Access cavities were sealed. After 8 months of incubation at 37 degrees C, viable E. faecalis was recovered from more teeth sealed with RoekoSeal (95%) compared with AH-Plus (40%) (p=0.0004, Fisher's exact test) and Roth's sealer (45%) (p=0.0012, Fisher's exact test). In the RoekoSeal groups, viable counts of E. faecalis OG1RF were higher than E. faecalis TX5128 (p=0.03, Mann-Whitney U test) suggesting that gelatinase activity plays a role in long-term survival of E. faecalis in obturated root canals.

Influence of residual bacteria on periapical tissue healing after chemomechanical treatment and root filling of experimentally infected monkey teeth

The purpose of this study was twofold: first, to determine the influence on the healing of the periapical tissues when selected bacterial strains and combinations thereof remain after root canal treatment; and, second, the relationship to healing of the quality of the root filling. In eight monkeys, 175 root canals, previously infected with combinations of four or five bacterial strains and with radiographically verified apical periodontitis, were endodontically treated, bacteriologically controlled, and permanently obturated. After 2-2.5 yr, the periapical regions were radiographically and histologically examined. Of these teeth, 48 root canals were also examined for bacteria remaining after removal of the root fillings. When bacteria remained after the endodontic treatment, 79% of the root canals showed non-healed periapical lesions, compared with 28% where no bacteria were found. Combinations of residual bacterial species were more frequently related to non-healed lesions than were single strains. When no bacteria remained, healing occurred independently of the quality of the root filling. In contrast, when bacteria remained, there was a greater correlation with non-healing in poor-quality root fillings than in technically well-performed fillings. In root canals where bacteria were found after removal of the root filling, 97% had not healed, compared with 18% for those root canals with no bacteria detected. The present study demonstrates the importance of obtaining a bacteria-free root canal system before permanent root filling in order to achieve optimal healing conditions for the periapical tissues.

Treatment Outcome in Endodontics: The Toronto Study. Phase III: Initial Treatment

The 4- to 6-year outcome of initial endodontic treatment was assessed for phase III (1998-1999) of the Toronto Study. Of the 532 teeth treated, 248 were from discontinuers (excluded), 142 from dropouts, 10 extracted, and 132 (50% recall) examined for outcome: healed (no apical periodontitis [AP], signs, symptoms) or diseased. Phase III was analyzed alone and combined with phases I, II (n = 373 teeth). Logistic regression performed on the combined phases I-III sample identified significant (p < or = 0.05) outcome predictors: preoperative AP (OR = 3.5; CI 1.7-7.2; healed: absent, 93%; present, 80%), number of roots (OR = 2.2; CI 1.0-4.7; healed: 1 - 92%; > or =2 - 83%), and intraoperative complications (OR = 2.2; CI 1.1-4.5; healed: absent, 88%; present, 76%). Treatment technique (OR = 2.8; CI 1.3-6.1; healed: Schilder, 89%; alternative, 73%) was suggested as an outcome predictor in teeth with AP, requiring confirmation from randomized controlled trials.

Ex vivo study of the efficacy of H-files and rotary Ni-Ti instruments to remove gutta-percha and four types of sealer

AIM

To compare the efficacy of ProFile rotary Nickel-Titanium (Ni-Ti) instruments and Hedstroem-files (H-files) combined with Gates-Glidden (GG) drills during removal of gutta-percha root fillings used in combination with one of the four representative sealers.

METHODOLOGY

Forty-eight single-rooted human teeth, with fully formed apices and straight root canals were used. The root canals were accessed and instrumented using a stepback technique with H-files. They were randomly assigned to four groups and subsequently filled with a combination of lateral and vertical condensation of gutta-percha and one of the following sealers: Roth 811, AH26, Endion and Roekoseal. The root fillings were removed 1 year later, using either H-files in combination with GG drills or the ProFile Ni-Ti system. Teeth were then grooved longitudinally and split. The amount of gutta-percha and sealer remaining on the root canal walls was traced and scored visually with the aid of a stereomicroscope. The scores were analysed and statistically compared with the Kruskal-Wallis test between the ProFile and H-file groups, as well as among the four sealer subgroups. Two samples from each group were studied under the scanning electron microscope to enhance inspection of canal walls and remaining material.

RESULTS

Sealer remnants were observed with both techniques mainly in the middle and apical third of the root canal. The ProFile system and the H-files were associated with similar amounts of remaining filling material (P > 0.05). In the cervical third of the root canal all sealer remnants were removed with both techniques. In the middle and apical third AH26 was associated with a statistically significant greater quantity of remnants on the root canal walls with both removal techniques (P < 0.05). Endion, Roth 811 and Roekoseal were associated with approximately the same amount of filling material in the middle third of the root canal (P > 0.05), whereas in the apical third Endion was associated with significantly more remnants of filling material than the other two sealers with either ProFile or H-files (P < 0.05).

CONCLUSIONS

None of the methods used for the removal of root fillings was totally effective, especially in the apical third of the root canal.

Levels of Evidence for the Outcome of Nonsurgical Endodontic Treatment

The purpose of this systematic review was (a) to search for clinical articles pertaining to success and failure of nonsurgical root canal therapy, and (b) to assign levels of evidence to these studies. Electronic and manual searches were conducted to identify studies published between January 1966 and September 2004 with information on the success and failure of nonsurgical root canal therapy. Articles were reviewed and graded for strength of level of evidence (LOE) from one (highest level) to five (lowest level). This review resulted in the identification of 306 clinical studies related to this topic area. Six articles were randomized controlled trials (RCTs, LOE 1). This search also identified 12 low-quality RCTs (LOE 2), 14 cohort studies (LOE 2), five case-control and eight cross sectional studies (LOE 3), four low-quality cohort studies (LOE 4), and five low-quality case-control studies (LOE 4). The majority (73) of the often-quoted "success and failure" studies were case series (LOE 4). The rest of the articles were descriptive epidemiological studies (42), case reports (114), expert opinions (18), literature reviews (4), and one meta-analysis. Based on these findings, it appears that a few high-level studies have been published in the past four decades related to the success and failure of nonsurgical root canal therapy. The data generated by this search can be used in future studies to specifically answer questions and test hypotheses relevant to the outcome of nonsurgical root canal treatment.

Soft Tissue Management in Endodontic Surgery

Modern endodontic surgery involves both root-end preparation and proper sealing of all apical portals of exit. Both components are requirements for mechanical and biological success, but the management of soft tissues becomes increasingly important for an esthetically successful treatment. A healthy appearance of soft tissues plays an important role in the esthetic outcome of periradicular surgery. This is true considering maintenance of attachment levels and regarding the amount of possible recession after surgical procedures. Complete, recession-free and predictable healing of gingival tissue is one important goal of endodontic surgical treatment. A critical review of currently used techniques based on clinical and scientific data reveals great potential for improvements. Possible reasons for scar formation and recession specifically in healthy periodontal conditions requiring surgical endodontic intervention are highlighted. Based on anatomical considerations various incision types are evaluated and recommendations made. Clear understanding of wound closure and tissue-healing patterns call for the use of atraumatic procedures, nonirritating suture materials and adequate suturing techniques. This article gives an overview and guidance for integrating current and new successful flap designs and wound closure methods. The methods described have the intention of maintaining the attachment level and avoiding postoperative recession after surgical endodontic therapy.

An analysis of endodontic treatment with three nickel-titanium rotary root canal preparation techniques

AIM

To investigate clinical results of root canal treatment performed with the aid of nickel-titanium (NiTi) rotary instruments.

SUMMARY

A total of 179 patients underwent root canal treatment with either (A) Lightspeed, or (B) ProFile .04 or (C) ProFile .04 and .06 or GT rotary instruments to create tapered preparations. In groups A and B, laterally condensed gutta-percha and AH Plus were used. Canals in group C were obturated with System B, Obtura II and Roth's 801 sealer. Initial and recall radiographs were assessed using the periapical index (PAI). Outcomes were analysed using chi-square tests, event-time analyses and logistic regression models. Two hundred and thirty-three teeth were radiographically assessed after a mean interval of 25.4 +/- 11.8 months. Favourable outcome of treatment, defined as PAI < 3 at recall was 86.7%. Logistic regression analysis and univariate analyses indicated that teeth with preoperative PAI scores >2 and retreated teeth had a significantly lower chance of healing compared with periapically healthy teeth and primary treatments, respectively. Preparation technique, length of fill and the type of sealer did not significantly affect healing rates.

KEY LEARNING POINTS

Root canal treatment with NiTi root canal instrumentation systems renders favourable outcomes in more than 86% of the cases. Outcome is significantly affected by preoperative diagnoses but not by the specific choice of instrumentation system.

Evaluation of Periapical Lesion Healing by Correction of Gray Values

The purpose of this study was to compare two methods for evaluating periapical healing in humans: the periapical index (PAI) and a gray value correction method. Fifty human teeth with a periapical lesion were endodontically treated. Radiographs, with a special aluminum device, were taken postoperatively, after 3 months and after 6 months. The PAI was recorded at each period of time, and a Kruskall and Wallis test was performed to compare the three groups. After scanning, the size of the lesion and its gray value were recorded. The aluminum device allowed the gray values to be equalized. An analysis of variance followed by a Duncan test was performed to compare the three groups. The teeth that showed no sign of healing according to the PAI were separately analyzed by an analysis of variance and a Duncan test. The PAI (n = 50) showed signs of periapical healing over time (p < 0.01). The analysis of variance, based on gray value evaluation (n = 50), also showed signs of periapical healing over time (p < 0.002). The analysis of variance of teeth with the same PAI over time (n = 15 at 3 months, and n = 5 at 6 months), based on gray value evaluation showed statistically significant differences among the 3 groups (p < 0.02). These results show that the gray level correction method is powerful and may reduce the risks of false negative responses during assessment of treatment results or epidemiological studies.

Cytotoxicity and sealing properties of four classes of endodontic sealers evaluated by succinic dehydrogenase activity and confocal laser scanning microscopy

The objectives of this study were to evaluate the cytotoxicity and sealing properties of four classes of endodontic sealers (PCS/Kerr, RoekoSeal/Roeko, TopSeal/Dentsply, and EndoREZ/Ultradent). For cytotoxicity testing (MTT method), the materials were either placed immediately in contact with cultured cells or 24 h after setting, then evaluated at three subsequent time points (24 h, 48 h, or 1 wk). For the leakage study, extracted human roots were obturated with acrylic cones and sealers and immersed for 48 h into rhodamine-labeled lipopolysaccharide. The roots were then observed under a confocal laser scanning microscope to estimate (semiquantitatively) the presence of the rhodamine-lipopolysaccharide (LPS) inside the canal. The results showed that cytotoxicity generally increased with time, and that most materials pose significant cytotoxic risks, particularly in the freshly mixed condition. Further, all materials showed significant leakage although there was large variation among teeth. Overall, the silicon-based material (Roeko Seal) was less cytotoxic and more effective in sealing root canals against LPS leakage than other materials.