Apical root canal microbiome associated with primary and posttreatment apical periodontitis: A systematic review.

BACKGROUND: Microorganisms colonizing the apical root canal system are conceivably the ones directly involved with the causation and maintenance of apical periodontitis. OBJECTIVES: This article systematically reviews the reports on the microbiome occurring exclusively at the apical root canal of teeth with primary and posttreatment apical periodontitis. METHODS: The electronic databases PubMed, Embase, Web of Science, Science Direct, and Proquest were searched up to August 2023. Clinical studies using culture and molecular microbiology methods to identify the microbial taxa present exclusively in the apical root canal segment of infected teeth with apical periodontitis were included. Studies were critically assessed using the Joanna Briggs Institute Critical Prevalence Assessment Checklist. RESULTS: From 2277 articles initially detected, 52 were selected for full reading and 21 were eventually included in this review. Of these, molecular methods were used in 19 and culture in 2 studies. Ten studies evaluated primary infections, 8 evaluated posttreatment infections, and 3 included both. Cryopulverization of the apical root specimens was conducted in 11 studies. All studies evaluated the prevalence and diversity of bacteria, and only one also reported on fungi. Overall, the most frequent/abundant bacterial taxa found in the apical canal of primary infections were Pseudoramibacter alactolyticus, Olsenella uli, Fusobacterium species, Streptococcus species, Porphyromonas endodontalis, Prevotella species, Actinomyces species, Parvimonas micra, Treponema denticola, Synergistetes species, and an as-yet uncharacterized taxon. In posttreatment infections, the most prevalent/abundant bacterial taxa included species of Streptococcus, Enterococcus, Fusobacterium, Actinomyces, Pseudoramibacter, Pseudomonas, and Propionibacterium. At the phylum level, Firmicutes was the most represented. The average apical bacterial load ranged from 105 to 106 in primary infections and from 103 to 104 in posttreatment infections. DISCUSSION: Microbial diversity in the apical part of the root canal system was examined encompassing data from both primary and posttreatment infections. Heterogeneity amongst the studies, especially in sample collection and microbial identification methods, is an important limitation that prevented a meta-analysis. CONCLUSIONS: There is a pronounced bacterial diversity in the infected apical canal, with a high interindividual variability. Different microbiome compositions at the species/genus level are observed according to the infection type. REGISTRATION: PROSPERO CRD42021275886.

Impact of root canal preparation using two single-file systems on the intra-radicular microbiome of teeth with primary apical periodontitis.

OBJECTIVES: This study aimed to describe the effects of two single-file systems on the diversity of the endodontic microbiome of teeth with primary asymptomatic apical periodontitis. MATERIALS AND METHODS: The root canals from single-rooted teeth with apical periodontitis were prepared using either the Reciproc Blue (RB) or the XP-endo Shaper (XPS) instrument system. The latter was followed by a supplementary step with the XP-endo Finisher (XPF) instrument. For irrigation, 5.25% sodium hypochlorite was used. Root canal samples were taken at the baseline (S1), after preparation (S2), and after the supplementary step (S3). DNA was extracted and subjected to high-throughput sequencing using the MiSeq Illumina platform. RESULTS: Samples from 10 teeth from the RB and 7 from the XPS group were subjected to DNA sequencing. Initial samples differed significantly from post-preparation samples in bacterial diversity, with no significant difference when comparing the two instrument systems. The most dominant phyla in S2 were Bacteroidetes, Proteobacteria, Firmicutes, Fusobacteria, and Actinobacteria. The same phyla were found to dominate baseline samples and samples taken after using XPF, but with differences in the ranking of the most dominant ones. At the genus level, the most dominant genera identified after RB instrumentation were Bacteroidaceae [G-1], Fusobacterium, and Staphylococcus, while the most dominant genera after XPS instrumentation were Fusobacterium and Porphyromonas. These genera were also dominant in the initial samples. CONCLUSIONS: Both treatment protocols had measurable effects on the root canal microbial diversity, with no significant differences between them. Most of the dominant taxa involved in the primary infection and probably in the aetiology of apical periodontitis were eliminated or substantially reduced. CLINICAL RELEVANCE: The most dominant taxa that persisted after instrumentation were Fusobacterium, Porphyromonas, Staphylococcus, and Bacteroidaceae [G-1].

Correlation Between Proinflammatory Cytokine Expression and Clinical Data in Apical Granuloma.

INTRODUCTION: This study was intended to evaluate the expression of inflammatory cytokines commonly secreted by CD4+ T cells (IL-2, IL-5, IL-17, TGF-ß, TNF-α, and IFN-γ) in apical granulomas and correlate with the clinical conditions and time elapsed since root canal treatment. METHODS: Eighteen biopsy specimens obtained by periradicular surgery of teeth with post-treatment apical periodontitis and diagnosed as apical granuloma were available from the oral pathology laboratory. Silanized slides containing paraffin sections were used for immunohistochemical reactions. Images were analyzed by using an optical microscopy and each slide was subdivided into 5 fields at high magnification. RESULTS: IFN-γ and TGF-ß were the cytokines with the highest expression levels. There were statistically significant differences when comparing IL-2 and IFN-γ (P < .05), and IL-2 and TGF-ß (P < .05). Comparison between the detected cytokines and clinical data and time of treatment demonstrated significant correlation (P < .05) between lower expression of IL-2 and the presence of painful symptoms, absence of sinus tract, and treatments performed more than 4 years before. It was also possible to observe a significant correlation between lower expression of IL-5 and treatments performed less than 4 years before (P < .05). CONCLUSION: IFN-γ and TGF-ß were highly expressed in apical granulomas. However, only IL-2 and IL-5 levels were associated with clinical data and time since previous root canal treatment.

Factors influencing the outcome of nonsurgical root canal treatment and retreatment: A retrospective study.

This study assessed the influence of diverse variables on the outcome of nonsurgical root canal treatment/retreatment. In general, 304 teeth from 218 patients were treated/retreated and the outcome evaluated by the periapical index (PAI). Teeth with apical periodontitis lesions that have not completely healed were classified as success or failure based on lenient and rigid criteria, respectively. Findings were evaluated using a logistic regression analysis. The overall success rates were 74% and 82% using the PAI-rigid and lenient success criteria, respectively. Specifically for treatment, the success rates were 73% (rigid) and 82% (lenient), while for retreatment they were 78% (rigid) and 83% (lenient). The treatment outcome was negatively affected by overextension, presence of preoperative lesion, lesion size >10 mm, and higher number of treatment visits (with no intracanal medication). Regarding retreatment, the chance of success was greater for teeth with adequate coronal restorations.

Bacteriologic Conditions of the Apical Root Canal System of Teeth with and without Posttreatment Apical Periodontitis: A Correlative Multianalytical Approach.

INTRODUCTION: This study used a correlative multianalytical approach to investigate the bacteriologic conditions in the apical root canal system of treated teeth with or without apical periodontitis and their correlation with the technical quality of the previous root canal obturation and the presence and volume of apical periodontitis lesions. METHODS: Root apexes were obtained from recently extracted root canal-treated teeth with (n = 23) and without (n = 22) apical periodontitis lesions as demonstrated by cone-beam computed tomographic examination. The root apexes were sectioned and subjected to micro-computed tomographic (micro-CT) scanning. The specimens were cryopulverized, and DNA extracted from the powder was used as a template in real-time polymerase chain reaction assays to quantify total bacteria and members of the Streptococcus genus and Actinobacteria phylum. The bacteriologic findings were compared between the 2 groups and also evaluated for associations with cone-beam computed tomographic and micro-computed tomographic data. RESULTS: Bacteria were detected in all apical canal samples except 1. The mean counts of total bacteria, streptococci, and actinobacteria did not differ significantly between teeth with or without apical periodontitis (P > .05). Streptococcus levels were significantly lower by 80% in the apical canals of teeth with small lesions compared with those without lesions (P < .05). The limit of filling >2 mm short was significantly associated with more total bacterial counts compared with canals filled 0-2 mm short (P < .05). An adequate coronal restoration was significantly associated with lesser counts of Streptococcus (P < .05). CONCLUSIONS: Comparable bacterial loads were observed in the apical canal system of treated teeth with and without apical periodontitis, suggesting that factors other than only the total bacterial levels may also influence the development and progression of apical periodontitis. Bacteria were found in the apical canal in virtually all cases with a high prevalence of streptococci and actinobacteria. Streptococci counts were significantly higher in the apical canal of teeth with inadequate restorations and teeth with no lesions. Underfilled canals showed higher bacterial counts.

Intracanal removal and apical extrusion of filling material after retreatment using rotary or reciprocating instruments: A new approach using human cadavers.

AIM: This study compared intracanal removal of filling as well as the frequency and volume of extruded material after retreatment with either HyFlex or Reciproc instruments in mandibular teeth from cadavers. METHODOLOGY: The root canals of 14 pairs of contralateral single-rooted teeth in mandibles of cadavers were instrumented with Reciproc R40 and filled using lateral compaction. The mandibles were scanned in a micro-computed tomographic (micro-CT) device before and after retreatment procedures. The contralateral teeth were assigned to two groups (n = 14) according to the retreatment protocol using either HyFlex or Reciproc instrument systems. In the HyFlex group, the HyFlex Remover instrument was worked 3 mm short of the working length (WL), followed by HyFlex CM 40.04 and 50.04 at the WL. In the Reciproc group, the R50 instrument was worked up at the coronal two thirds, followed by two more cycles until the WL was reached. Pre- and post-operative micro-CT images were analysed for extrusion and intracanal removal of filling material. RESULTS: After retreatment, extrusion of filling material occurred in 11 (78%) and 14 (100%) teeth from HyFlex and Reciproc groups respectively (p > .05). A similar volume of extruded material was observed after retreatment with both systems (p > .05). A significant decrease in the intracanal filling volume was verified after retreatment with both tested systems (p < .05). However, residual filling material was found in all root canals, regardless of the system. The amount of filling material removed (HyFlex = 80.8%; Reciproc = 65.9%) and the operation time was similar between systems (p > .05). CONCLUSIONS: A high frequency of filling material extrusion was observed after retreatment with the two systems in a cadaver model, with no significant difference between them. Both protocols obtained similar efficacy in filling material removal procedures, although none completely cleaned the canals.

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.

Multipopulation evaluation of the internal morphology of mandibular first premolars from different South American countries. A micro-computed tomography study.

OBJECTIVE: To evaluate and compare several anatomical parameters of mandibular first premolars from individuals from different Latin American countries using micro-computed tomography. DESIGN: Five hundred extracted mandibular first premolars from Brazilian, Argentinian, Chilean, Colombian, and Ecuadorian individuals were scanned using micro-computed tomography (n = 100 teeth/country). Root canal configurations were classified according to established parameters. Analyses also included: canal volume and surface area, structure model index, distances from the apical foramen to the root apex or the cementoenamel junction, major/minor apical canal diameters, canal orifice shape, and prevalence of ramifications. RESULTS: A single root was the most common anatomy in all countries (range, 97%-100%). Vertucci's type-I canal was the most frequent configuration (range, 36%-66%), followed by C-shaped and type-V canals. The oval-shaped canal orifice was the most predominant in all countries (range, 34%-58%), followed by the circular shape (range, 16%-47%). C-shaped canals occurred in all subpopulations (range, 14%-26%), always associated with radicular grooves. Ranges for canal ramifications were as follows: accessory canals, 36%-73%; lateral canals, 4%-12%; and apical delta, 4%-14% of the teeth. Many anatomic parameters differed significantly between countries (P < .05). CONCLUSIONS: Vertucci's types-I and -V, and C-shaped canals were the most prevalent configurations in the subpopulations investigated. Accessory canals and several complex anatomies were found, with some significantly different frequencies between countries.

Disinfection and Shaping of Vertucci Class II Root Canals after Preparation with Two Instrument Systems and Supplementary Ultrasonic Activation of Sodium Hypochlorite.

INTRODUCTION: This study compared disinfection and shaping after root canal preparation with either XP-endo Shaper or TruNatomy instrument systems, supplemented by ultrasonic activation of sodium hypochlorite (NaOCl) with either stainless-steel (SS) or nickel-titanium (NiTi) inserts. METHODS: Mesial roots from mandibular molars with Vertucci class II configuration were divided into 2 groups (n = 24) based on anatomically paired micro-computed tomography (micro-CT) analyses. Pre and postpreparation micro-CT scans were obtained to evaluate the shaping performance. The canals were contaminated with a mixed bacterial culture for 30 days and then subjected to preparation with either XP-endo Shaper or TruNatomy instruments using NaOCl irrigation. Supplementary ultrasonic activation of NaOCl was conducted using either an SS (TruNatomy group) or NiTi (XP-endo Shaper group) insert. Bacteriological samples were taken from the canals before preparation (S1), after preparation (S2), and after the supplementary approach (S3). Bacterial reduction was evaluated using a quantitative real-time polymerase chain reaction. RESULTS: Preparation with both instrument systems significantly reduced bacterial counts (P < .01). After preparation, 36% (TruNatomy) and 35% (XP-endo Shaper) were negative for bacteria. These values increased to 59% and 65% after ultrasonic activation with the SS and NiTi inserts, respectively. The quantitative data in S2 showed that XP-endo Shaper promoted a significantly higher bacterial reduction than TruNatomy (P < .05). No significant intragroup differences were observed after ultrasonic activation (P > .05), probably because the SS insert promoted a significantly higher S2-to-S3 reduction than the NiTi insert (P < .01). Micro-CT analysis revealed no significant differences in the unprepared areas between the groups (P > .05). CONCLUSIONS: The XP-endo Shaper caused a significantly higher bacterial reduction than TruNatomy in Vertucci class II canals. Better antibacterial results after ultrasonic activation were observed for the SS ultrasonic inserts than for the NiTi inserts.

Shaping ability of BlueShaper, TruNatomy, DC Taper and HyFlex EDM in long oval canals: An ex vivo study.

AIM: This study evaluated and compared the shaping ability of four rotary instrument systems in long-oval root canals using microcomputed tomographic (micro-CT) evaluation. Currently, there is no data available on the canal shaping abilities of BlueShaper and DC Taper instruments. METHODOLOGY: Sixty-four single-rooted mandibular premolars were matched based on similar root canal morphologic features as determined by (micro-CT) and randomly assigned to 1 of 4 experimental groups (n = 16) according to the instrument system used: BlueShaper, TruNatomy, DC Taper and HyFlex EDM One File. Changes in the root canal surface and volume, remaining dentine thickness, and number of prepared areas were assessed. RESULTS: No significant differences were found amongst the four instrument systems for the parameters evaluated (p > .05). There was a significant reduction in the number of unprepared areas and the remaining dentine thickness after each increase in size of the instruments tested (p < .05). CONCLUSIONS: The four instrument systems perform similarly in long oval root canals. Although none could prepare all canal walls, larger preparations incorporated significantly more surfaces in the final shape.

Influence of brushing motions on the shaping of oval canals by rotary and reciprocating instruments.

OBJECTIVE: The effects of brushing on shaping with three different instruments were assessed in oval canals. DESIGN: Mandibular incisors were assigned to 6 groups (n = 12/group) according to the system, each one with or without brushing: Reciproc Blue, VDW.Rotate, and Race EVO. Micro-computed tomography was performed before and after preparation. RESULTS: Brushing strokes caused no increase in canal volume, surface area, and structure model index independently of the system (p > 0.05), except for RaCe EVO in the full canal surface area (p < 0.05). Brushing did not increase the prepared areas (p > 0.05), except for Reciproc in the apical canal (p < 0.05). Reciproc with no brushing exhibited less pericervical dentin than with brushing (p < 0.05), while RaCe EVO with brushing resulted in less remaining dentin (p < 0.05). CONCLUSIONS: The brushing motion had no effects on the overall shaping performance of the 3 instruments tested. An exception was the increase in prepared surface area in the apical canal segment when the Reciproc instrument was used with brushing strokes.

Histologic Features of External Cervical Resorption Affecting Impacted Maxillary Canines: A Report of 2 Cases.

Reports on the histopathologic features of external cervical resorption (ECR) in unerupted teeth are scarce. This article reports on 2 maxillary impacted canines from different patients that showed ECR lesions and were surgically removed and histologically evaluated. Case 1 showed symptoms associated with oral communication of the dental follicle and pulpal exposure. Radiographs and cone-beam computed tomographic imaging showed that resorption affected a large part of the root and the crown. Case 2 was asymptomatic, and the resorption cavity was restricted to the tooth crown. Both teeth were extracted and subjected to histologic processing and analysis. In case number 1, the coronal pulp was necrotic and infected, showing areas of exposure to the resorption channels. The apical pulp was vital and uninflamed. The pulp space was surrounded by a continuous pericanalar resorption-resistant sheet. Part of the resorbed area of dentin was occupied by inflamed granulation tissue. More apically, a network of trabecular bone was present in the resorbed area. In case number 2, the pulp around the resorbed area was uninflamed and vital. A large fraction of the lost dentin was replaced by trabecular bone, closely adapted to the irregularly resorbed dentin surface, and no inflammatory cells. Our findings indicate that impacted teeth with ECR may remain asymptomatic until associated with infection. Histologic features of resorption in impacted teeth were similar to those in erupted teeth. In the case associated with infection, the resorbed area was occupied by inflamed tissue and newly formed bone. In the case with no infection, the resorption area was filled with bone undergoing a remodeling process.

Surgical management of a lateral lesion refractory to root canal retreatment caused by an extraradicular calculus. A case report.

This article describes the management of a root canal-treated maxillary central incisor displaying a radiographic lateral radiolucency and a sinus tract that persisted irrespective of root canal retreatment following high standards. Endodontic microsurgery was indicated and curettage of the pathologic tissue revealed a calculus-like material attached to the outer root surface around the exit of a large lateral canal. A non-conventional approach was chosen: No root-end resection was conducted. Instead, the calculus was removed and the apical surface was scaled and smoothed, conserving the apical structure. Retrocavities were prepared in both lateral and apical foramens and filled with a bioceramic material. Follow-up examination showed optimal soft tissue healing. One-year follow-up of radiographs revealed healing of the lateral lesion. The lesion was diagnosed as a cyst, with an infected lumen. An exuberant calculus-like material attached to the external root surface was the most likely cause of the recalcitrant lateral periradicular lesion.

Post-treatment apical periodontitis associated with a missed root canal in a maxillary lateral incisor with two roots: A case report.

Missed canals can be a common cause of persistent intraradicular infection and post-treatment apical periodontitis. This article reports on a rare case of a maxillary lateral incisor with two roots exhibiting symptomatic post-treatment apical periodontitis regardless of a radiographically adequate root canal treatment. The second root, which was only revealed by cone-beam computed tomography, had passed unnoticed during the first treatment, and its missed canal was the most likely cause of symptoms and treatment failure. Reintervention including the proper management of the extra root canal and retreatment of the main canal resulted in the resolution of symptoms and periradicular tissue healing. This case report reinforces the need for three-dimensional radiographic diagnosis to search for the cause of post-treatment disease and guide the decision-making process for proper management.

Effects of Calcium Hydroxide Paste in Different Vehicles on Bacterial Reduction during Treatment of Teeth with Apical Periodontitis.

INTRODUCTION: This clinical study evaluated the antibacterial effects of calcium hydroxide associated with different vehicles during the treatment of infected teeth with apical periodontitis. METHODS: Bacteriologic samples were taken from 90 necrotic root canals of teeth with apical periodontitis before (S1) and after preparation with a rotary nickel-titanium instrument system and 2.5% sodium hypochlorite irrigation (S2). The teeth were distributed in 3 groups according to the intracanal medication used, which consisted of a calcium hydroxide paste in glycerin, camphorated paramonochlorophenol/glycerin (CHPG), or 2% chlorhexidine for 1 week, and then another sample was taken (S3). The frequency of bacteria-positive cases and the reduction of bacterial counts were evaluated by quantitative real-time polymerase chain reaction. RESULTS: Substantial intracanal bacterial reduction was observed after preparation in the 3 groups (P < .001). After calcium hydroxide paste in glycerin medication, the number of bacteria-positive cases decreased from 20/29 (69%) to 17/29 (59%); however, the mean bacterial counts increased 8.4% from S2 to S3. Medication with CHPG reduced the number of bacteria-positive cases from 17/29 (59%) to 15/29 (52%), with a significant mean S2-S3 reduction of 71% (P < .05). In the chlorhexidine group, the number of bacteria-positive cases decreased from 21/30 (70%) to 17/30 (57%) after medication, with a mean S2-S3 reduction of 55%, which, however, was not statistically significant (P > .05). Intergroup comparisons showed no significant differences (P > .05). CONCLUSION: Comparison between the 3 calcium hydroxide pastes showed no significant differences in antibacterial effectiveness in the main root canal. However, only the CHPG paste showed a significant reduction in bacterial counts when postpreparation and postmedication samples were compared.

The Oral Microbiota in Health and Disease: An Overview of Molecular Findings.

Culture-independent nucleic acid technologies have been extensively applied to the analysis of oral bacterial communities associated with healthy and diseased conditions. These methods have confirmed and substantially expanded the findings from culture studies to reveal the oral microbial inhabitants and candidate pathogens associated with the major oral diseases. Over 1000 bacterial distinct species-level taxa have been identified in the oral cavity and studies using next-generation DNA sequencing approaches indicate that the breadth of bacterial diversity is even much larger. Nucleic acid technologies have also been helpful in profiling bacterial communities and identifying disease-related patterns. This chapter provides an overview of the diversity and taxonomy of oral bacteria associated with health and disease.

Microbial Community Profiling Using Terminal Restriction Fragment Length Polymorphism (T-RFLP) and Denaturing Gradient Gel Electrophoresis (DGGE).

In their natural environments, microorganisms usually live in organized communities. Profiling analysis of microbial communities has recently assumed special relevance as it allows a thorough understanding of the diversity of the microbiota, its behavior over time, and the establishment of patterns associated with health and disease. The application of molecular biology approaches holds the advantage of including culture-difficult and as-yet-uncultivated phylotypes in the profiles, providing a more comprehensive picture of the microbial community. This chapter focuses on two particular techniques, namely terminal restriction fragment length polymorphism (T-RFLP) and denaturing gradient gel electrophoresis (DGGE), both of which have been widely used in environmental studies and have been recently successfully used by the authors in the study of the oral microbial communities associated with conditions of health and disease.

Outcome of Direct Pulp Capping Using Calcium Hydroxide: A Long-term Retrospective Study.

INTRODUCTION: This retrospective study evaluated the long-term outcome of direct pulp capping in mature teeth using specific case selection and treatment procedures. METHODS: Teeth with pulp exposure due to advanced caries and clinical diagnosis of reversible pulpitis were treated by direct pulp capping. Treatments were conducted over a period of 15 years by a single operator. Under magnification, caries was completely removed, the exposed pulp examined, and capped with either pure calcium hydroxide or a calcium hydroxide-based cement. The cavity was restored and the long-term outcome evaluated from 1 to >35 years. Teeth that were asymptomatic, responded to sensibility pulp tests within normal limits, and showed no radiographic periapical changes were categorized as success. Teeth with no response to pulp tests and/or showing radiographic evidence of apical periodontitis were classified as failures. The effects of independent variables (sex, age, symptoms, number and size of pulp exposures, bleeding time, capping material, bases used over the capping material, and final coronal restoration) on the outcome were evaluated. RESULTS: In general, 225 teeth from 148 patients were available for follow-up examination in at least one of the evaluated periods. The success rate of the direct pulp capping procedure was 100%, 95%, 95%, 86%, and 89% at 1-, 5-, 10-, 20-, and 35-year follow-up examination, respectively. The main variable significantly affecting the treatment outcome in all follow-up periods was the quality/presence of coronal restoration (P < .001). Other isolated variables associated with the outcome included the size and number of pulp exposures at the 20-year follow-up, and the exposure size, capping material, and restoration type at the 35-year follow-up. Multiple regression analysis confirmed the results for exposure size (P < .05), and disclosed a higher proportion of failures at 5 years when varnish was used as the base. CONCLUSIONS: A very high success rate of the direct pulp capping with calcium hydroxide was observed, especially in the first 10 years following treatment. The main variable influencing the outcome was the quality of the coronal restoration.

Regenerative Endodontic Therapy for Management of an Immature Permanent Tooth with Recurrent Post-treatment Apical Periodontitis: A Case Report.

This case report describes the treatment outcome and further retreatment of an immature permanent maxillary right central incisor with necrotic pulp and chronic apical abscess using regenerative endodontic therapy (RET). The patient had a history of traumatic injury. The initial periapical radiographic and cone-beam computed tomographic (CBCT) examinations revealed tooth #8 had incomplete root formation, thin dentinal walls, and pulp necrosis associated with a large apical periodontitis lesion. RET was conducted in two visits and included a disinfection protocol with 5.25% NaOCl irrigation and medication with a double antibiotic paste (metronidazole and ciprofloxacin). At the second visit, a blood clot was induced, and the cervical third was sealed with a mineral trioxide aggregate plug and the coronal portion with light-cure composite. The tooth was asymptomatic at the 12-, 24-, and 36-month follow-ups, and radiographs showed continued root development with healed periradicular tissues. However, the 4-year radiographic follow-up revealed a recurrent apical periodontitis lesion. A second attempt of RET was conducted in one visit using 1% NaOCl irrigation and stimulation of a blood clot. A double seal with silicate-based cement and composite was placed. At the 24-month follow-up, the tooth remained asymptomatic, and both radiographic and CBCT examinations showed apical closure and complete repair of the periradicular tissues. When a tooth develops recurrent apical periodontitis, a second attempt of RET is a feasible option to control infection, helping to promote tooth retention associated with healthy periradicular conditions.

Shaping ability of new reciprocating or rotary instruments with two cross-sectional designs: An ex vivo study.

AIM: This study compared the shaping ability of four new reciprocating and rotary nickel-titanium instruments, with triangular or S-shaped cross-section, in the mesial canals of mandibular molars using micro-computed tomographic (micro-CT) evaluation. METHODOLOGY: Twenty-four extracted mandibular molars with Vertucci's class IV configuration in the mesial root were selected for this study. The teeth were matched in fours according to anatomic similarities as revealed by micro-CT and then distributed into four groups of 12 mesial canals each according to the instrumentation technique: Reciproc Blue, R-motion, VDW.Rotate and RaCe EVO. The final apical size of instrumentation was 30/0.04 for three systems and 25/08 for the Reciproc Blue instrument. Micro-CT scans were taken before and after preparation to evaluate the canal volume, area and unprepared surface areas, as well as the centring ability, and the canal: root width ratio. RESULTS: Preparation with all systems significantly increased the volume and area of the canals (p < .05). There were no significant differences between groups regarding the amount of unprepared areas in both the apical and full canal lengths (p > .05). Variation in the centre of gravity showed no significant difference between groups either (p > .05). The canal: root width ratio at levels 0 and 4 mm apically to the coronal canal opening was significantly increased by all systems (p < .01), with no significant differences between groups (p > .05). The canal width never exceeded 40% of the root width. CONCLUSIONS: Reciprocating or rotary instruments, with a triangular or an S-shaped cross-section, performed equally in shaping Vertucci's class IV mesial canals of mandibular molars.