Evaluation of quality of root canal therapy performed by predoctoral students on endodontic outcome and quality of life of patients.

This study evaluated the technical quality (TQ) of root canal therapy (RCT) performed by predoctoral students and its impact on endodontic outcome (EO) and patients' quality of life (QoL). The TQ of RCT done by predoctoral students was evaluated and follow-up visits were conducted to determine the clinical, radiographic outcome of RCT and patients' QoL. Frequency distribution, multiple regression, independent-samples t test and one-way anova were performed. A total of 226 teeth of 164 patients were clinically and radiographically examined. A satisfactory TQ was observed in 130 (57.5%), successful clinical outcomes in 155 (68.6%), successful radiographical outcomes in 206 (91%) and overall successful EO in 150 teeth (66.4%) with 80% of patients reporting a favourable QoL. A significant positive correlation was noted between EO and QoL (p = 0.002) with no significant correlation in between TQ-RCT and EO (p = 0.07) and TQ-RCT and QoL (p = 0.316). Successful EO had a positive impact on patients' QoL.

Prevalence of apical periodontitis and quality of root canal treatment in an adult Kuwaiti sub-population: a cross-sectional study.

Objectives: This cross-sectional study evaluated the prevalence of apical periodontitis (AP) and the technical quality of root canal fillings in an adult Kuwaiti subpopulation using cone-beam computed tomography (CBCT) images. Materials and Methods: Two experienced examiners analyzed 250 CBCT images obtained from Kuwaiti patients aged 15-65 years who attended government dental specialist clinics between January 2019 and September 2020. The assessment followed the radiographic scoring criteria proposed by De Moor for periapical status and the technical quality of root canal filling. Chi-square and Fisher's exact tests were used for statistical analysis, with significance level set at p < 0.05. Results: Among the 2,762 examined teeth, 191 (6.91%) exhibited radiographic signs of AP, and 176 (6.37%) had undergone root canal filling. AP prevalence in root canal-treated teeth was 32.38%, with a significant difference between males and females. Most of the endodontically treated teeth exhibited adequate root canal filling (71.5%). Conclusions: The study demonstrated a comparable prevalence of AP and satisfactory execution of root canal treatment compared to similar studies in different countries.

The role of systemic statins in the inception and healing of apical periodontitis: a systematic review.

OBJECTIVES: Statins are a category of medications widely used to reduce plasma LDL-cholesterol levels, that also possess antibacterial, anti-inflammatory, and immunomodulatory action. The aim of this systematic review was to explore the effects of systemic statins therapy on the development and treatment of apical periodontitis (AP) on humans and animals. MATERIAL AND METHODS: Three electronic databases (PubMed, Web of Science, and Scopus) and grey literature were searched from their inception until February, 20 2023 (PROSPERO CRD42021246231). For the quality assessment and risk of bias, different guidelines were used according to the typology of the studies considered (Animal Research Reporting of In Vivo Experiments, Newcastle-Ottawa Quality Assessment Form for Cohort Studies, Systematic Review Centre for Laboratory animal Experimentation Risk of Bias tool and Tool to assess risk of bias in cohort studies of CLARITY Group). RESULTS: Seven hundred eleven records were screened, and six articles were included for this qualitative review. The eligible studies showed a moderate overall quality and risk of bias. Human patients in treatment with statins exhibited a higher healing rate of AP following root canal treatment. In experimental animal models, statins had a beneficial effect on the development of AP. CONCLUSIONS: Despite the limited number of studies and considering that most of them are on animals, our findings suggest that systemically administered statins make a positive contribution to prevent the development and help healing of AP. CLINICAL RELEVANCE: There is an increased evidence that a pharmacologic adjunct to endodontic treatment may be considered to enhance healing of AP. Among other medications, statins seem to have a positive impact on the disease.

Long-term follow-up of equine incisor endodontic treatments using an orthograde technique.

OBJECTIVE: This retrospective clinical study was performed to determine the suitability and success rate of endodontic treatment of equine incisors presenting with apical and periapical disease. ANIMALS: All horses presented to a referral equine dental clinic between March 2013 and December 2019 specifically selected as candidates suitable for endodontic treatment were included in this study. METHODS: Initial clinical and radiographic presentation of incisor disorder cases suitable for endodontic treatment were recorded (88 incisors) and follow-up examination for long-term viability (8 months to 5 years) was performed in cases involving 32 incisors in total. RESULTS: A total of 68 horses with 88 incisors were included in this study for endodontic restorative treatment. Different dental materials were used, with a temporary 3-layered technique using calcium hydroxide apically and temporary cement and resin composite occlusally most commonly used at the first treatment. Complete obturation with resin composite was performed in 48% of the cases requiring second treatments (50 incisors). Follow-up examination involving 32 incisors showed that successful endodontic treatment was achieved in 75% of the teeth treated. CLINICAL RELEVANCE: Endodontic treatment of diseased incisors is a viable option in equid patients with a success rate comparable to humans in practice. The use of flowable resin composite as an obturation material has been shown to be successful at either the second treatment or in carefully selected patients at the first treatment.

Endodontic Outcome of Root Canal Treatment Using Different Obturation Techniques: A Clinical Study.

OBJECTIVE: To evaluate the clinical outcome of root canal treatment by obturation technique, root canal filling quality, and tooth- and patient-related variables. METHODS: This clinical study investigated the endodontic outcome of 114 teeth treated between the years 2009 and 2012. Three different obturation methods were used: (1) adhesive obturation using the continuous wave of condensation technique with Resilon® (CWR), (2) matching-taper single-cone technique with gutta-percha and AH Plus® (SCGP), and (3) matching-taper single-cone technique with gutta-percha and GuttaFlow® (SCGF). Pre- and postoperative periapical radiographs were performed to detect the presence of endodontic lesions (PAI classification) and to assess the quality of both the obturation and the restoration. Tooth- and patient-related data were collected. RESULTS: The overall endodontic success rate was 75.4% after a mean observation period of 6.3 years. There were no significant correlations between the type or overall quality of obturation and the treatment outcome. Teeth with preoperative lesions had the highest odds ratio (factor of 4.98) for endodontic failure. Tooth- and patient-related variables had no significant effect on endodontic outcome. CONCLUSIONS: The preoperative periapical status of teeth requiring endodontic treatment was a substantial prognostic factor for endodontic outcome, whereas the type of obturation material or technique did not affect it.

The Effect of Unintentional AH-Plus Sealer Extrusion on Resolution of Apical Periodontitis After Root Canal Treatment and Retreatment-A Retrospective Case-control Study.

INTRODUCTION: This study aimed to investigate the effect of unintentional AH Plus sealer extrusion on the outcome of nonsurgical root canal treatment and retreatment in teeth with apical periodontitis (AP) compared to teeth with AP and no sealer extrusion at the 1-year follow-up. METHODS: In a retrospective case-control study conducted from September 2016 to September 2021, teeth presenting clinical and radiographic signs of AP prior to treatment were included. The study comprised 2 groups: AH Plus sealer extrusion group (n = 60): initial root canal treatment or nonsurgical retreatment with unintentional apical extrusion of AH Plus sealer; and no AH Plus sealer extrusion group (n = 60): underwent the same treatment types without sealer extrusion. Additional factors, including sex, age, tooth type, tooth location, and treatment type, were recorded as potential outcome predictors. At 1-year follow-up, teeth were evaluated clinically and radiographically, and outcomes were classified as favorable (healed/healing) or unfavorable (uncertain/non-healing). Statistical analyses, such as the χ2 test, logistic regression, and Mann-Whitney U test, were employed for data analysis. RESULTS: A favorable outcome was observed in 88.4% and 85% of the cases of the AH Plus sealer extrusion and no AH Plus sealer extrusion groups, respectively. There was no statistically significant difference between the groups in terms of outcomes (P > .05) when analyzed categorically or ordinally. Of independent variables, nonsurgical retreatment showed lower healing of AP in both groups. CONCLUSIONS: Unintentional AH Plus sealer extrusion did not affect the healing of AP. However, initial root canal treatment showed better healing of AP than nonsurgical retreatment in the presence of AH Plus sealer extrusion. The analyzed outcome predictors had no effect on treatment outcome.

An Endodontic Forecasting Model Based on the Analysis of Preoperative Dental Radiographs: A Pilot Study on an Endodontic Predictive Deep Neural Network.

INTRODUCTION: This study aimed to evaluate the use of deep convolutional neural network (DCNN) algorithms to detect clinical features and predict the three-year outcome of endodontic treatment on preoperative periapical radiographs. METHODS: A database of single-root premolars that received endodontic treatment or retreatment by endodontists with presence of three-year outcome was prepared (n = 598). We constructed a 17-layered DCNN with a self-attention layer (Periapical Radiograph Explanatory System with Self-Attention Network [PRESSAN-17]), and the model was trained, validated, and tested to 1) detect 7 clinical features, that is, full coverage restoration, presence of proximal teeth, coronal defect, root rest, canal visibility, previous root filling, and periapical radiolucency and 2) predict the three-year endodontic prognosis by analyzing preoperative periapical radiographs as an input. During the prognostication test, a conventional DCNN without a self-attention layer (residual neural network [RESNET]-18) was tested for comparison. Accuracy and area under the receiver-operating-characteristic curve were mainly evaluated for performance comparison. Gradient-weighted class activation mapping was used to visualize weighted heatmaps. RESULTS: PRESSAN-17 detected full coverage restoration (area under the receiver-operating-characteristic curve = 0.975), presence of proximal teeth (0.866), coronal defect (0.672), root rest (0.989), previous root filling (0.879), and periapical radiolucency (0.690) significantly, compared to the no-information rate (P < .05). Comparing the mean accuracy of 5-fold validation of 2 models, PRESSAN-17 (67.0%) showed a significant difference to RESNET-18 (63.4%, P < .05). Also, the area under average receiver-operating-characteristic of PRESSAN-17 was 0.638, which was significantly different compared to the no-information rate. Gradient-weighted class activation mapping demonstrated that PRESSAN-17 correctly identified clinical features. CONCLUSIONS: Deep convolutional neural networks can detect several clinical features in periapical radiographs accurately. Based on our findings, well-developed artificial intelligence can support clinical decisions related to endodontic treatments in dentists.

Outcome of selective root canal retreatment-A retrospective study.

AIM: Selective root canal retreatment is when the treatment is limited to root(s) with radiographic evidence of periapical pathosis. The goals of this retrospective study were as follows: (i) evaluate the clinical and radiographic (periapical radiographs [PR] or cone-beam computerized tomographs [CBCT]) outcome of selective root canal retreatment after ≥12 months follow-up; (ii) evaluate the periapical status of the unretreated roots; and (iii) assess tooth survival. METHODOLOGY: A retrospective study (January 2018 to April 2021) was conducted to identify permanent multirooted teeth that underwent selective root canal retreatment. Clinical records, PR and CBCT were examined to ascertain variables of interest. Outcomes (per root and per tooth) were classified into 'favourable' or 'unfavourable' using well-established clinical and radiographic healing criteria. Treatment outcomes for the whole tooth and per root were compared as well as bivariate associations between the treatment outcome of the retreated roots and the treatment-related parameters (quality of root filling, sealer extrusion, iatrogenic mishaps and type of restoration) were analysed using Fisher's exact test (α = .05). Survival was recorded in months. RESULTS: A total of 75 teeth (195 roots) in 75 subjects were available for outcome analysis. The favourable outcome per tooth was 86.7%. At follow-up, 92.6% of the retreated roots had a favourable outcome. From the unretreated roots, 3.5% showed radiographic signs of an emerging periapical lesion. No statistical difference was shown between the outcomes per root and per tooth between both groups. None of the treatment-related parameters had a direct influence on the outcome of the retreated roots. The survival rate at 12-48 months after retreatment was 91.5%. CONCLUSIONS: Selective root canal retreatment is associated with a favourable outcome in a majority of cases. Unretreated roots rarely developed radiographic signs of a new periapical lesion at follow-up. Future high-quality clinical trials with larger sample sizes and longer follow-up periods are required to confirm these findings.

A 12-month follow-up of primary and secondary root canal treatment in teeth obturated with a hydraulic sealer.

OBJECTIVES: This randomized, controlled, pilot study assessed the outcome of non-surgical primary/secondary root canal treatments either with a novel bioactive sealer and the single-cone technique or with gutta-percha, zinc oxide-eugenol sealer (ZOE), and warm vertical compaction. MATERIALS AND METHODS: Sixty-nine patients were randomly divided into two groups that were treated using the single-cone technique with BioRootTM RCS (Septodont) (BIO group) or warm vertical compaction with gutta-percha and ZOE sealer (PCS group). Two subsamples (BIOAP and PCSAP) comprised the cases with apical periodontitis. Treatment was undertaken by four residents using a standardized instrumentation and disinfection protocol. The periapical index (PAI) was recorded, and clinical and radiographic follow-up performed at 1, 3, 6, and 12 months. Treatment success was assessed according to "periapical healing" and "tooth survival". The test for the equality of proportions, t tests for the equality of means, and non-parametric K-sample tests for the equality of medians were applied when appropriate. RESULTS: The survival rate was similar in the BIO and PCS (p = 0.4074) and the BIOAP and PCSAP groups (p = 0.9114). The success rate was higher in the BIO groups, but not statistically significant (p = 0.0735). In both BIOAP and PCSAP groups, a progressive decrease in the PAI was observed. CONCLUSION: At 12 months, both techniques showed reliable results. Further studies and longer follow-ups are needed. CLINICAL RELEVANCE: This study documents the feasibility of using a bioactive sealer in conjunction with the single-cone technique to obturate the root canal and obtaining a predictable outcome. TRIAL REGISTRATION: ClinicalTrials.gov Identifie: NCT04249206.

The impact of cardiovascular disease and endodontic outcome: a systematic review of longitudinal studies.

OBJECTIVES: To date, the relationship between cardiovascular disease (CVD) and endodontic treatment outcomes remains elusive with mixed reports. Thus, the purpose of this systematic review of longitudinal cohort studies was to evaluate whether CVD was a risk factor for endodontic outcome. MATERIALS AND METHODS: Two reviewers independently conducted a comprehensive electronic database search to July 2020. The bibliographies of all relevant articles, textbooks, and gray literature were manually searched. The methodological quality of evidence was appraised by the Newcastle-Ottawa Scale and GRADE. The authors considered any publication on CVD and endodontic outcome. Endodontic outcome referred to either healing or survival of endodontically treated tooth. Risk ratio (RR) with 95% confidence interval (CI) was used. RESULTS: Three articles met the inclusion criteria with a low risk of bias. Patients with CVD demonstrated a 67% higher risk for negative endodontic outcomes compared with patients who were healthy (RR = 1.67, P = 0.001, 95% confidence interval 1.53-1.81). CONCLUSION: With the limitations of this systematic review, the overall confidence by GRADE was moderate suggesting that CVD might be a risk factor for endodontic outcomes. CLINICAL RELEVANCE: The results support an association between CVD and endodontic outcomes.

Diabetes mellitus and the healing of periapical lesions in root filled teeth: a systematic review and meta-analysis.

BACKGROUND: Diabetes mellitus (DM) may affect the healing and survival of root filled teeth with periapical lesions. AIM: To systematically analyse the available clinical literature to evaluate the association between DM and the prevalence of radiolucent periapical lesions in root filled teeth. The review question was 'Is there a difference between the root canal treatment healing outcome (in terms of presence or absence of radiolucent periapical lesions) in diabetic and non-diabetic patients?'. DATA SOURCES: A systematic review of cross-sectional studies and prospective clinical trials was conducted according to the PRISMA checklist. The review involved a search of the electronic databases of PubMed, Scopus and EBSCO host. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS: The research protocol was previously registered in the International Prospective Register of Ongoing Systematic Reviews (CRD42019130954) and included defined inclusion/exclusion criteria. The included studies were related to the root canal treatment outcome in diabetic patients in terms of periapical radiolucent lesions associated with root filled teeth. STUDY APPRAISAL AND SYNTHESIS: The selected studies were critically analysed by two evaluators using the Joanna Briggs Institute Critical Appraisal tool. The pooled odds ratio (OR) was recognized as the primary outcome variable and measure of the effect for the occurrence of periapical lesions associated with root filled teeth of control and diabetic patients. The random-effects Mantel-Haenszel method was used, at a 95% confidence interval, to calculate the pooled OR. A funnel plot was created to evaluate possible sources of heterogeneity. RESULTS: Ten studies published between 1989 and March 2019 were selected after thorough analysis and exclusion according to the strict criteria. Seven cross-sectional studies, 1 longitudinal and 2 prospective clinical studies were included. The pooled OR was calculated by comparing 773 diabetic subjects and 1133 control subjects. The pooled OR for the observational studies and clinical studies were 1.42 and 6.36, respectively. This value signified a high prevalence of periapical lesions in root filled teeth in diabetic subjects. LIMITATIONS: There are limited prospective clinical trials on this topic. The majority of the included studies are observational. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: The data suggest a strong connection between the presence of periapical radiolucency on root filled teeth amongst diabetics as determined by the pooled OR.

A retrospective assessment of different endodontic treatment protocols.

BACKGROUND: The aim of this study was to assess the clinical impact of non-surgical root canal treatments (NSRCT) performed with different treatment protocols on the probability of tooth survival without untoward events and to identify predictors influencing the outcome. METHODS: During the period from July 1999 to October 2016, 5,858 patients were identified in which 9,967 NSRCTs were performed. The treatments were followed up and divided into three groups. In Group 1 root canal treatment was performed with hand instruments, in Group 2 with multiple file rotary instruments and passive ultrasonic irrigation (PUI), and Group 3 was treated with Reciproc instruments and PUI. Untoward events were defined as orthograde retreatment, apicoectomy or extraction of the tooth after initial treatment. Weibull regression was used to analyse the data. RESULTS: A total of 9,938 cases could be included into the analyses. The results showed 5-years predicted survival rates without untoward events of 73.9% (95% CI [71.7%-76.1%]), 75.1% (95% CI [71.7%-78.0%]) and 78.4% (95% CI [75.1%-81.4%]) for study group 1 (N = 5,580), 2 (N = 1,700) and 3 (N = 2,658), respectively. The differences between Group 1 and 3 were statistically significant (p < 0.006). Higher age of the patient (per year increase) and number of earlier NSRCTs (per unit increase) reduce the survival without untoward events statistically significant (both p < 0.02), while treatment of premolars had a statistically significant lower hazard ratio [0.89 (95% CI [0.79-0.99]; p = 0.030)] compared to treatment of molars and anterior teeth. A higher number of supportive periodontal treatments (per unit increase) improved tooth survival without untoward events highly significant (p < 0.0001). DISCUSSION: More recent endodontic treatment protocols involving reciprocating instruments and PUI appear to be associated with higher tooth survival rates without untoward events compared to hand instruments.

Relationship between unintentional canal overfilling and the long-term outcome of primary root canal treatments and nonsurgical retreatments: a retrospective radiographic assessment.

AIM: To determine retrospectively the long-term radiographic outcome of root canal treatments and root canal retreatments with unintentional root canal overfilling. METHODOLOGY: A total of 220 root canal treatments (143 primary/77 retreatments) with postoperative unintentional canal overfilling and performed by two endodontists during their 45 years of private practice were included in the study. Lateral condensation techniques and nine different sealers were used. Overfilling was confirmed with a postoperative periapical radiograph and patients were scheduled regularly for recall visits. Average recall time was 4.86 years (maximum = 30 years). Two calibrated observers evaluated the radiographs and determined the long-term outcome using the PAI score pooled in a 3-category scale. The persistence or resorption of the extruded material was registered. The Kappa coefficient (K) was calculated and a logistic regression was used for further analysis. Odds ratios and their 95% CI were estimated. RESULTS: The level of inter-observer agreement was 66.1%. Primary root canal treatments had a significantly (P = 0.015) greater rate of success (91.6%) than retreatments (81.8%). Tooth location (P = 0.019) was the only other factor that significantly affected the outcome. The type of extruded material, and its resorption or persistence did not relate to the outcome. Persistence of extruded material was significantly affected by tooth location and recall time after treatment. CONCLUSION: The outcome of root canal treatment with unintentional canal overfilling was not associated with the type of extruded material or its resorption or persistence. The persistence of extruded material did not relate to a favourable or unfavourable outcome.

Cone-beam Computed Tomography Compared with Intraoral Radiographic Lesions in Endodontic Outcome Studies: A Systematic Review.

INTRODUCTION: The purpose of this systematic review was to compare and quantify endodontic outcome using cone-beam computed tomographic (CBCT) imaging with intraoral periapical radiography. METHODS: Two reviewers independently conducted a comprehensive literature search. The MEDLINE, Embase, Cochrane, and PubMed databases were searched. Additionally, bibliographies, gray literature of all relevant articles, and textbooks were manually searched. There was no disagreement between the 2 reviewers. RESULTS: Six articles met the inclusion criteria with low to moderate risk of bias (good/fair quality). The certainty of evidence was moderate, indicating that the authors are moderately confident that the true effect lies close to that of the estimate of the effect as determined by Grading of Recommendations Assessment Development and Evaluation criteria. The odds ratio of CBCT imaging versus traditional imaging to detect a periapical lesion was 2.04 (95% confidence interval, 1.52-2.73). CONCLUSIONS: Although intraoral radiographs are the imaging modality of choice, when 2-dimensional intraoral radiography is inconclusive, CBCT imaging was reported in this investigation to have twice the odds of detecting a periapical lesion than traditional periapical radiography in endodontic outcome studies.

Association between Systemic Diseases and Endodontic Outcome: A Systematic Review.

INTRODUCTION: To date, the relationships between systemic diseases and endodontic treatment outcomes remain poorly studied. Thus, the purpose of this systematic review was to evaluate the relationship between host-modifying factors and their association with endodontic outcomes. METHODS: Two reviewers independently conducted a comprehensive literature search. The MEDLINE, Embase, Cochrane, and PubMed databases were searched. In addition, the bibliographies and gray literature of all relevant articles and textbooks were manually searched. There was no disagreement between the 2 reviewers. RESULTS: Sixteen articles met the inclusion criteria with moderate to high risk of bias. There was no article with low risk of bias. Available scientific evidence remains inconclusive as to whether diabetes and/or cardiovascular disease(s) may be associated with endodontic outcomes. Human immunodeficiency virus and oral bisphosphonate did not appear to be associated with endodontic outcomes. CONCLUSIONS: Although additional well-designed longitudinal clinical studies are needed, the results of this systematic review suggest that some systemic diseases may be correlated with endodontic outcomes.

Prevalence of Apical Periodontitis in Endodontically Treated Premolars and Molars with Untreated Canal: A Cone-beam Computed Tomography Study.

INTRODUCTION: The purpose of this retrospective cohort study was to evaluate the incidence of missed canals in endodontically treated teeth in the Greater Philadelphia area patient population and to evaluate the effect of untreated canals on endodontic outcome. METHODS: A total of 1397 cone-beam computed tomography (CBCT) volumes taken from January 2013 to July 2015 were investigated. Limited view CBCT images were taken with Kodak 9000 3D System field of view at voxel size, 76 µm or Morita Veraviewpocs 3D F40 field of view at voxel size, 125 µm. All root canal-treated premolars and molars were included in the study. Unfilled canals appearing from cementoenamel junction to apex including splitting from a main canal at coronal, mid, or apical third were defined as missed-untreated canal. A periapical lesion was diagnosed when disruption of the lamina dura was detected and the low density area associated with the radiographic apex was at least twice the width of the periodontal ligament space. RESULTS: The overall incidence of missed canals was 23.04%. The incidence of missed canals per tooth was highest in tooth #14 at 46.5% and tooth #3 at 41.3%. The incidence of missed canals was highest in the upper molars at 40.1% and lowest in the upper premolars at 9.5%. There was a significant difference in lesion prevalence when a canal was missed-untreated (P < .05). Teeth with a missed canal were 4.38 times more likely to be associated with a lesion. CONCLUSIONS: Limited field-of-view CBCT should be examined before any endodontic retreatment to identify missed canals. This knowledge would not only help clinicians to locate missed canals clinically but would also help in deciding the surgical approach.

The Tennessee study: factors affecting treatment outcome and healing time following nonsurgical root canal treatment.

AIM: To determine factors that may influence treatment outcome and healing time following root canal treatment. METHODOLOGY: Root filled and restored teeth by pre-doctoral students were included in this study. Teeth/roots were followed-up regularly, and treatment outcome was evaluated at every follow-up appointment (healed, healing, uncertain or unsatisfactory). Host (age, immune condition, pulp/periapical diagnosis, tooth/root type, location and anatomy) and treatment factors (master apical file size, apical extension, voids and density of root filling) were recorded from patient dental records. Univariate, bivariate and multivariate analyses were performed to determine the impact of the factors on treatment outcomes and healing times. RESULTS: A total of 422 roots from 291 teeth met the inclusion criteria with a mean follow-up period of 2 years. The preoperative pulp condition, procedural errors during treatment, apical extension and density of root fillings significantly affected the treatment outcome. The average time required for a periapical lesion to heal was 11.78 months. The healing time increased in patients with compromised healing, patients older than 40 years, roots with Weine type II root canal systems, root canal systems prepared to a master apical file size <35, and roots with overextended fillings (P < 0.1). CONCLUSION: Multiple host and treatment factors affected the healing time and outcome of root canal treatment. Follow-up protocols should consider these factors before concluding the treatment outcome: patient's age, immune condition, as well as roots with overextended fillings, root canal systems with smaller apical preparations (size <35) or roots with complex canal systems. Intervention may be recommended if the treatment quality was inadequate or if patients became symptomatic.

Investigation of cultivable bacteria isolated from longstanding retreatment-resistant lesions of teeth with apical periodontitis.

INTRODUCTION: The objective of this research was to investigate the presence of viable bacteria in tissue samples from persistent apical lesions and to correlate the microbiological findings with the histopathological diagnosis of the lesion. METHODS: Twenty persistent apical lesions associated with well-performed endodontic retreatment were collected. Tissue samples were processed through culture techniques including serial dilution, plating, aerobic and anaerobic incubation, and biochemical tests for microbial identification followed by histopathological diagnosis. RESULTS: Cysts were more frequently diagnosed (13/20). Strict anaerobic species predominated in both cysts (80.4% of the species detected) and granulomas (65% of the species detected). Viable gram-positive bacteria were frequently recovered from apical lesions (cysts = 70.6%, granulomas = 84.4%). Gemella morbillorum and Propionibacterium acnes were the most frequently recovered species from cysts and granulomas, respectively. At least 1 gram-positive bacterial species was present in almost every sample (cysts = 12/13, granulomas = 7/7). No significant correlation was found between histologic findings and bacterial species. CONCLUSIONS: In conclusion, although cysts were more frequent than granulomas in cases of failure of endodontic retreatment, bacteria were isolated from both types of lesions, with a predominance of gram-positive species, suggesting that these species can survive outside the root canal and might be related to the persistence of the pathological process even after accurate endodontic retreatment.

Quantitative and qualitative analysis of microorganisms in root-filled teeth with persistent infection: Monitoring of the endodontic retreatment.

OBJECTIVE: The aim of this study was to investigate in vivo microorganisms detected in root-filled teeth with post-treatment apical periodontitis and quantify colony-forming units (CFU) during endodontic retreatment. MATERIALS AND METHODS: Fifteen root-filled teeth had their previous gutta-percha removed and were randomly instrumented before being divided into three groups and medicated with either [Ca(OH)2 + 2% CHX gel], [Ca(OH)2 + 0.9% NaCl] or 2% CHX gel. Samples were taken after removal of gutta-percha (S1), after chemomechanical preparation using 2% CHX gel (S2), and after inter-appointment dressing (S3) for 7 or 14 days later. Cultivable bacteria recovered from infected root canals at the three stages were counted and identified by means of culture and PCR assay (16S rDNA). Quantitative data were statistically analyzed by using Mann-Whitney test in which pairs of groups were compared (P < 0.05). RESULTS: CFU counts decreased significantly from S1 to S2 (P < 0.05). No significant difference was found between S2 and S3 (P = 0.3093) for all three experimental groups. Chemomechanical preparation and intra-canal dressing promoted significant median reductions of 99.61% and 99.57%, respectively, in the number of bacteria compared to S1 samples. A total of 110 cultivable isolates were recovered by culture technique from 32 different species and 7 different genera. Out of the 13 target species-specific primer of bacteria analyzed, 11 were detected during endodontic retreatment. CONCLUSION: The great majority of taxa found in post-treatment samples were Gram-positive bacteria, although Gram-negative bacteria were found by molecular methods. Moreover, our results showed that gutta-percha removal and chemomechanical preparation are effective for root canal disinfection, whereas additional intra-canal dressing did not improve disinfection.