Pulp biopsies from the teeth associated with periapical radiolucency

Efficacy of imaging techniques for the diagnosis of apical periodontitis: A systematic review

BACKGROUND

Apical periodontitis (AP) is a chronic inflammatory response of microbial aetiology. Pathological changes associated with AP may not be visible on radiographic images and may linger without causing any symptoms. Clinicians rely mostly on clinical examination and imaging techniques to establish a diagnosis.

OBJECTIVES

The aim of this review was to answer the following question using the PICO format: In the adult human permanent dentition (P), what is the efficacy of diagnostic imaging of the periapical tissues (I) using histopathology as a reference standard (C) in the diagnosis of apical periodontitis, in terms of diagnostic accuracy (O).

METHODS

MEDLINE, EMBASE, Scopus and Cochrane Library were searched for English articles published through October 2021. At least two independent reviewers evaluated the study design, imaging modality used, histopathological assessment, outcome measures, results and conclusions for each article. The risk of bias was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies-2.

RESULTS

The initial search strategy identified 544 articles. Seven articles were included for analysis in the final review, all of which involved tissue samples obtained from cadavers. No clinical studies were identified that met the eligibility criteria. A consistently low sensitivity score and negative predictive value were reported for periapical radiography, especially in comparison to CBCT, which scored highly. Both modalities achieved high scores for specificity and positive predictive value. Diagnostic accuracy of CBCT was lower for root-filled teeth in comparison to non-root-filled teeth.

DISCUSSION

Assessment of the periapical tissues using periapical radiographs was shown to have a low to moderate agreement with the histopathological assessment. CBCT was reported to be more accurate than PR and demonstrated a good agreement with histopathology, especially for non-root-filled teeth.

CONCLUSIONS

This review identified a need for greater standardization in methodology and reporting, and as the findings are based on cadaver studies, their clinical relevance must be interpreted with caution.

REGISTRATION

PROSPERO (CRD42021272147).

Vital pulp therapy for permanent teeth with diagnosis of irreversible pulpitis: biological basis and outcome

Root canal treatment (RCT) has been considered the conventional standard for the management of teeth with carious pulp exposure, particularly in mature teeth presenting with symptoms. Following a better understanding of the histopathology of deep carious lesions, the histology of the cariously exposed pulp and the healing potential of the inflamed pulp, vital pulp therapy (VPT) is increasingly adopted around the world for the management of permanent teeth with clinical signs and symptoms indicative of irreversible pulpitis. Furthermore, VPT became a recognized treatment modality by the European Society of Endodontology (ESE) and the American Association of Endodontists (AAE) by virtue of its high success rates reported in outcome studies using contemporary hydraulic calcium silicate-based cements. However, proper case selection, strict asepsis, capping materials and good coronal seal are mandatory for success. The aim of this paper is to review the biological basis for VPT in symptomatic teeth with carious pulp exposure and to report on the outcome of pulpotomy in teeth with clinical diagnosis of irreversible pulpitis.

Histologic and Electron Microscopic Characterization of a Human Immature Permanent Premolar with Chronic Apical Abscess 16 years after Regenerative Endodontic Procedures

Previous studies have reported successful clinical outcomes after regenerative endodontic procedures (REPs) for immature permanent teeth with pulpal infection. However, it remains unclear whether the procedures promote true regeneration or repair. This case report describes the histologic and electron microscopic characteristics of a human immature permanent premolar with a chronic apical abscess that was treated with an REP. Tooth #20 of a 9-year-old girl underwent an REP. At the 6-year follow-up, the patient was asymptomatic, and closure of the apex and thickening of the dentinal walls were observed. However, 16 years after the procedure, apical periodontitis recurred, necessitating apical surgery. The resected root fragments were obtained during the surgery and analyzed using micro-computed tomography, light microscopy, and scanning electron microscopy. Distinct dentinal tubules and interglobular dentin were observed in the regenerated hard tissue. Cementum-like tissue and a root canal were also observed in the apical fragment. The regenerated root tissue in this case exhibited a structure similar to the native root structure. Therefore, we believe that cell-free REPs possess regenerative potential for teeth diagnosed with pulp necrosis and chronic apical abscess.

Factors that influence the outcome of pulpotomy in permanent teeth

The promotion of minimally invasive treatments focussed on the maintenance of pulp vitality has become a priority area in Endodontics. These vital pulp treatments (VPT) include partial and full pulpotomy, during which diseased coronal pulp tissue is removed prior to placement of a capping biomaterial and restoration. Traditionally, pulpotomies were confined to the treatment of carious primary and traumatized permanent teeth. However, these treatments have now been proposed as definitive solutions for cariously exposed permanent teeth with mild symptoms or even symptoms indicative of irreversible disease. Until recently, it was recommended that carious exposure of mature permanent teeth be managed by root canal treatment. The promotion of pulpotomy as an alternative treatment has opened up a wave of laboratory and clinical research aimed at improving therapies or evaluating clinical outcomes. In modern evidence-based endodontics, it is imperative that the outcomes of both partial and full pulpotomy are considered and important prognostic factors identified, so that improvements can be made to aid clinical decision-making and to direct new research. In this narrative review, the outcomes of partial and full pulpotomy are discussed, before analysis of patient, intraoperative and postoperative factors that influence the outcome of the pulpotomy procedure. The review highlights that although partial and full pulpotomy for the treatment of even pulpal disease are highly successful procedures, this is based on low-quality evidence with a lack of prospective, comparative trials investigating potential prognostic factors. Based on current evidence, it appears that age, gender, tooth type, root development and intraoperative pulpal haemorrhage do not impact significantly on pulpotomy outcome, whilst others such as caries depth, inflammatory status of the pulp, capping material, level of inflammatory pulpal-biomarkers and the final restoration integrity do. Other factors, including the influence of exposure type, periodontal condition, pulpal lavage, magnification, operator experience, isolation of the operating field and type of pulpotomy, require further experimental investigation before definitive conclusions can be made relating to the success of the pulpotomy procedure. Finally, there is not only a need for future well-designed prospective research addressing these issues but also a widening of our understanding of outcome to include patient-reported as well as clinician-reported outcomes.

Modified pulpotomy procedure in immature permanent teeth with apical periodontitis: a randomised controlled trial

OBJECTIVES

The objective of this study was to evaluate the effectiveness of a modified pulpotomy (MP) procedure in immature permanent teeth with apical periodontitis (AP).

DESIGN

Randomised controlled trial.

SETTING

One public hospital in Shanghai, China PARTICIPANTS: A total of 33 teeth (31 patients) with a definitive diagnosis of AP with radiographic periapical radiolucency were recruited in this study. All the patients (teeth) completed the study accordingly.

METHODS AND INTERVENTION

Patients were randomly assigned to either MP or apexification treatment groups and were followed up for 12 months. Clinical symptoms and complications were recorded, and parallel periapical radiographic images were used to measure changes in root length and apical diameter. Wilcoxon's rank sum test and Fisher's exact test were used to compare the clinical and radiographic outcomes between MP and apexification, and analysed with analysis of variance.

MAIN OUTCOME MEASURE

The primary outcome was increase in root length at 12 months. The secondary outcomes included tooth survival, clinical success and decrease in apical diameter.

RESULTS

MP group showed a significant increase in root length (10.05%±2.14% vs 1.16%±0.79%, p<0.05) at 12 months and a decrease in apical diameter (48.88%±10.42% vs 15.90%±8.88%, p<0.05) as compared with the apexification group. The tooth survival rate was 100%, and 90.91% (30/33) of teeth were asymptomatic with apical healing in both treatment groups (p>0.05).

CONCLUSIONS

MP can be an option for treating immature permanent teeth with AP. MP showed better performance in terms of continued root maturation than apexification. MP and apexification achieved comparable outcomes with regard to the resolution of clinical symptoms and apical healing.

TRIAL REGISTRATION NUMBER

ChiCTR-INR-17012169.

Investigating the residual effect of silver nanoparticles gel as an intra-canal medicament on dental pulp stromal cells

BACKGROUND

The aim of this study was to evaluate the indirect effects of residual silver nanoparticles (AgNPs) gel on human dental pulp stromal cells (DPSCs).

METHODS

Ninety-five dentin discs (4x4x1 mm) were prepared from freshly extracted human single-rooted teeth following institutional ethical approval and informed consent. Samples were cleaned, autoclaved, and treated with: 1.5%NaOCl, Saline and 17% EDTA then randomly assigned to 5 groups that received 50 μl of one of the following treatments: 0.01%AgNPs, 0.015%AgNPs, 0.02%AgNPs, Calcium hydroxide (Ca (OH)₂) or no treatment for 1 week. Discs were washed with Saline and 17%EDTA then seeded with DPSCs and incubated for 3 and 7 days. At 24 hours unattached cells were collected and counted. At each time point cytotoxicity (LDH assay), cell viability (live/dead staining and confocal microscopy) and cell proliferation (WST1 assay) were assessed. All experiments were repeated a minimum of 3 times using DPSCs isolated from 3 different donors for each time point assessed (n = 9/group). Statistical analysis was done using One-Way ANOVA followed by Tukey's test and Kruskal Wallis followed by post-hoc comparisons with significance set at p ≤ 0.05.

RESULTS

After 24 hours, the percentage of DPSCs attachment ranged between 92.66% ±4.54 and 95.08% ±1.44 with no significant difference between groups (P = 0.126). Cell viability was ≥92% at 24 hours for all groups. However this percentage dropped to less than 60% at 3 days then started to rise again at 7 days. There was no significant difference in cytotoxicity between different groups at all time points except for 0.01%AgNPs group which had the highest cytotoxicity. DPSCs proliferation increased significantly from 3 to 7 days in all groups except for Ca (OH)₂ which showed lower proliferation rates at both 3 (45.89%) and 7 days (79.25%).

CONCLUSION

Dentin discs treated for 7 days with concentrations of AgNPs gel (0.01-0.02%) allowed more than 90% DPSCs cell attachment after 24 hours. The cytotoxicity and proliferation of DPSCs in response to AgNPs gel were comparable to those with calcium hydroxide. This suggests that AgNPs gel may represent a promising future candidate for clinical use in regenerative endodontics. However, its effects may be concentration-dependent warranting further investigation.

Reparative Endodontic Treatment of a Perforating Internal Inflammatory Root Resorption: A Case Report

The aim of this case report was to present a reparative treatment approach of an extensive internal inflammatory resorption with a lateral perforation and apical and lateral inflammatory lesions. Only the necrotic coronal part of the pulp was removed, and the vital pulp tissue within the resorption cavity and the apical part of the root canal was left uninstrumented. Bleeding was induced, and the blood clot was covered with mineral trioxide aggregate. Hard tissue repair and healing of the apical lesion could be observed in the 3-year recall.

Orthodontic Movement after Regenerative Endodontic Procedure: Case Report and Long-term Observations

INTRODUCTION

Although regenerative treatment approaches in teeth with incomplete root formation and pulp necrosis have become part of the suggested therapeutic endodontic spectrum, little is known about the effect of orthodontic movement in the tissue that has been regenerated. Furthermore, as the number of adults undergoing orthodontic treatment increases, there is an increasing need to investigate the changes that these tissues may undergo during orthodontic movement. Here we describe the alterations observed after the application of orthodontic forces in a case of an apically root-fractured necrotic immature root that had been managed with regenerative endodontic procedures in the past.

METHODS

A 9-year-old male patient was referred after suffering the third incidence of trauma in the anterior maxilla. Radiographic evaluation revealed a periapical rarefaction associated with an apically root-fractured immature central incisor. Clinical evaluation revealed a buccal abscess and grade 3 tooth mobility. Periodontal probing was within normal limits. The tooth was accessed and disinfected by using apical negative pressure irrigation of 6% NaOCl. Intracanal dentin conditioning was achieved by using 17% EDTA for 5 minutes. A blood clot was induced from the periapical area, and calcium silicate-based cement was placed in direct contact with the blood clot at the same visit. The composite resin restoration was accomplished in the same appointment.

RESULTS AND CONCLUSIONS

Recall radiographic examination after 24 months revealed healing of the periapical lesion and signs of continuous root development despite the apical root fracture. Clinical evaluation revealed normal tooth development, normal mobility, and a resolving buccal infection. The tooth was subjected to orthodontic treatment because of Class II division 1 malocclusion with an overjet of 11 mm. After completion of the orthodontic treatment, 5.5 years after the initial intervention, the radiographic image revealed marked remodeling of the periapical tissues and repair of the apical fractures, and the buccal infection had resolved completely.

Paradigm Shift from Stem Cells to Cell-Free Regenerative Endodontic Procedures: A Critical Review

Regenerative endodontic procedures of immature teeth with necrotic pulp have become a part of therapeutic endodontic spectrum and are considered as an alternative to calcium hydroxide or mineral trioxide aggregate apexification. In last decade, numerous case reports and series with usage of cell-free approaches known as revascularization, revitalization, or maturogenesis have been published. This cell-free approach prevails in clinical regenerative endodontics because of its relative ease of performance, lower financial demands, and absence of complications such as tumorigenesis of used stem cells. In this article, the integral steps of cell-free treatment approaches such as source of stem cells, possible endogenous scaffolds, sources of growth factors, and width of apical foramen in the context of sufficient disinfection of root canal system and outcome of treatment are discussed. Despite not being a fully established treatment protocol, the achieved outcomes are promising regardless of it having a reparative character than a regenerative one.

Retreatment of failed regenerative endodontic of orthodontically treated immature permanent maxillary central incisor: a case report

A revascularization procedure was shown to be the best alternative therapy for immature teeth with necrotic pulp and apical infection. A 12 year old female with a history of trauma to her upper central incisor and a sinus tract was referred for endodontic treatment. She was an active orthodontic patient and had undergone regenerative endodontic treatment for the past 2 years. Clinical examination revealed no response to sensibility, percussion, and palpation tests. The preoperative radiograph showed an open apex and apical rarefaction. The case was diagnosed as previously treated tooth with asymptomatic apical periodontitis. Regenerative endodontic retreatment was performed, and the case was followed for 3 years. Clinical, radiographic, and cone-beam computed tomography follow-up examination revealed an asymptomatic tooth, with evidence of periapical healing and root maturation.

Scanning electron microscopy reveals severe external root resorption in the large periapical lesion

The present study was designed to investigate the relationships between clinicopathological findings and the resorptive conditions of root apices of teeth with periodontitis. The samples included 21 root apices with large periapical radiolucent lesions. The preoperative computed tomography (CT) and intraoperative findings were correlated with the presence, extension, and the progression pattern of periapical resorption using a scanning electron microscope. The subjects' age, gender, chief complaint, type of tooth, percussion test results, size of periapical lesion using CT, and intraoperative findings were recorded. All apicoectomies were performed under an operative microscope for endodontic microsurgery. A significant large size was observed in cystic lesions compared with granulomatous lesions. The cementum surface at the periphery of the lesion was covered with globular structures (2-3 μm in diameter). Cementum resorption started as small defect formations at the surface. As the defect formation progressed, a lamellar structure appeared at the resorption area, and the size of globular structures became smaller than that of globules at the surface. Further resorption produced typical lacuna formation, which was particularly observed in fracture cases. The most morphologically severe destructive pattern of dentin resorption was observed in large cystic lesions. This study is the first report to elucidate the relationships between three clinical types of undesirable periapical lesions: (1) undertreatment, (2) periapical fracture, (3) macro-level resorption, and the microstructure of external root resorption including from small defects at the cementum surface to a significant destructive pattern inside the dentin. Microsc. Res. Tech. 79:495-500, 2016. © 2016 Wiley Periodicals, Inc.

Pulp revascularization of immature maxillary first premolar

An immature maxillary first premolar in an 8-year-old female was treated using a regenerative approach. The root canal was gently irrigated with 5.25% sodium hypochlorite without instrumentation under aseptic conditions and then medicated with calcium hydroxide (Ca[OH]₂) for 3 weeks. The Ca(OH)₂ was removed, and bleeding was initiated mechanically using a hand file to form an intracanal blood clot. Mineral trioxide aggregate was placed over the blood clot, and the access cavity was sealed with a double filling. Increases in root length and width were radiographically evident, at the 6-month follow-up exam. The case was followed for 3 years. The development of 3 roots with complete apical closure was confirmed using cone beam computed tomography.

Biofilm in endodontics: A review

Endodontic disease is a biofilm-mediated infection, and primary aim in the management of endodontic disease is the elimination of bacterial biofilm from the root canal system. The most common endodontic infection is caused by the surface-associated growth of microorganisms. It is important to apply the biofilm concept to endodontic microbiology to understand the pathogenic potential of the root canal microbiota as well as to form the basis for new approaches for disinfection. It is foremost to understand how the biofilm formed by root canal bacteria resists endodontic treatment measures. Bacterial etiology has been confirmed for common oral diseases such as caries and periodontal and endodontic infections. Bacteria causing these diseases are organized in biofilm structures, which are complex microbial communities composed of a great variety of bacteria with different ecological requirements and pathogenic potential. The biofilm community not only gives bacteria effective protection against the host's defense system but also makes them more resistant to a variety of disinfecting agents used as oral hygiene products or in the treatment of infections. Successful treatment of these diseases depends on biofilm removal as well as effective killing of biofilm bacteria. So, the fundamental to maintain oral health and prevent dental caries, gingivitis, and periodontitis is to control the oral biofilms. From these aspects, the formation of biofilms carries particular clinical significance because not only host defense mechanisms but also therapeutic efforts including chemical and mechanical antimicrobial treatment measures have the most difficult task of dealing with organisms that are gathered in a biofilm. The aim of this article was to review the mechanisms of biofilms’ formation, their roles in pulpal and periapical pathosis, the different types of biofilms, the factors influencing biofilm formation, the mechanisms of their antimicrobial resistance, techniques to identify biofilms.

Considerations for regeneration procedures

When pulp tissue becomes necrotic in immature teeth, the prognosis of the teeth is compromised. Disinfection of the root(s) presents several challenges including difficulties in cleaning and shaping large canals with open apices, obturation of canals with open apices, and potential root fractures caused by thin and/or weakened root walls. Regenerative endodontic procedures may increase the prognosis of the compromised immature tooth by re-establishment of a functional pulp tissue that fosters continued root development and immune competency. This article reviews the literature related to and discuss considerations for regenerative endodontic procedures and how these procedures may increase the prognosis for immature teeth with necrotic pulp tissue.

Conservative treatment of immature teeth with apical periodontitis using triple antibiotic paste disinfection

The purpose of this report is to present conservative treatment for two immature premolars with apical periodontitis. A triple antibiotic paste was used to disinfect the root canal systems for revascularization. In both cases, residual vital pulp tissue was noted in the root canal system after the opening of each premolar. The canals in both cases were irrigated with copious sodium hypochlorite solution and medicated with a paste consisting of ciprofloxacin, metronidazole, and minocycline. The teeth were sealed with mineral trioxide aggregate and restored with composite resin. There were satisfactory outcomes after 18 months. The patients were asymptomatic, with radiographic evidence of complete resolution of radiolucency, continual thickening of dentinal walls, apical closure, and increased root length.

Conventional apexification and revascularization induced maturogenesis of two non-vital, immature teeth in same patient: 24 months follow up of a case

Various authors have demonstrated the regenerative process in immature, non vital teeth by revascularization induced maturogenesis. The aim of this case report is to compare calcium hydroxide apexification and pulp revascularization induced maturation procedures in the same patient, in two different teeth. The right maxillary central incisor in this individual was treated with conventional calcium hydroxide induced apexification procedure followed by guttaperchaobturation, and the left maxillary central incisor was treated by pulp revascularization induced maturation procedures. 24 months follow-up shows root elongation and apical closure in the tooth treated with revascularization induced maturation procedures. Revascularization induced maturogenesis, where indicated, can provide several advantages over conventional apexification procedures.

Dental stem cells for tooth regeneration and repair

Mesenchymal stem cells (MSCs) resident in bone marrow are one of the most studied and clinically important populations of adult stem cells. Cells with, similar properties to these MSCs have been described in several different tooth tissues and the potential ease with which these dental MSCs could be obtained from patients has prompted great interest in these cells as a source of MSCs for cell-based therapeutics. In this review we address the current state of knowledge regarding these cells, their properties, origins, locations, functions and potential uses in tooth tissue engineering and repair. We discuss some of the key controversies and outstanding issues, not least of which whether dental stem cells actually exist.

Pulp revascularization of immature teeth with apical periodontitis: a clinical study

INTRODUCTION

The purpose of this study was to examine the effect of a pulpal revascularization procedure for immature necrotic teeth with apical periodontitis.

METHODS

Twelve patients, each with an immature permanent tooth with chronic or acute apical periodontitis, were recruited. A triantibiotic mix (ciprofloxacin, metronidazole, and minocycline) was used to disinfect the pulp for 1 week. Then a blood clot was created in the canal, over which grey mineral trioxide aggregate was placed. Patients were recalled periodically.

RESULTS

Six patients dropped from the study (as a result of pain or failure to induce bleeding after canal disinfection) and instead received a standard apexification procedure. Another 3 patients did not attend any recall appointments. The remaining teeth (n = 3) were found to exhibit complete root development, with a positive response to pulp testing.

CONCLUSIONS

Revascularization could be effective for managing immature permanent teeth with apical periodontitis with appropriate case selection.

The hidden treasure in apical papilla: the potential role in pulp/dentin regeneration and bioroot engineering

Some clinical case reports have shown that immature permanent teeth with periradicular periodontitis or abscess can undergo apexogenesis after conservative endodontic treatment. A call for a paradigm shift and new protocol for the clinical management of these cases has been brought to attention. Concomitantly, a new population of mesenchymal stem cells residing in the apical papilla of permanent immature teeth recently has been discovered and was termed stem cells from the apical papilla (SCAP). These stem cells appear to be the source of odontoblasts that are responsible for the formation of root dentin. Conservation of these stem cells when treating immature teeth may allow continuous formation of the root to completion. This article reviews current findings on the isolation and characterization of these stem cells. The potential role of these stem cells in the following respects will be discussed: (1) their contribution in continued root maturation in endodontically treated immature teeth with periradicular periodontitis or abscess and (2) their potential utilization for pulp/dentin regeneration and bioroot engineering.

Incidence of periapical lesions and clinical symptoms after pulpectomy—A clinical and radiographic evaluation of 1- versus 2-session treatment

OBJECTIVE

Outcome of pulpectomy in 2 treatment sessions with calcium hydroxide as an intracanal dressing was compared to a procedure comprising instrumentation and root-filling in 1 session.

STUDY DESIGN

Subjects with a vital pulp condition (N = 256) were recruited to a randomized clinical trial. Outcome parameters included radiographic signs of apical periodontitis and painful symptoms at clinical follow-ups 1 week and 1-3 years after treatment.

RESULTS

Of 244 subjects available for final recall, 17 presented with periapical radiolucency. Lesions were evenly distributed among the 2 treatment groups. Postoperative pain recorded 1 week after permanent filling was significantly associated with overfilling (P = .001), with no difference between treatment groups. There was no association with presence of overfilling and radiographic lesion at end point of recall.

CONCLUSIONS

Study confirms that pulpectomy may be carried out at a high rate of success if due attention is given to aseptic operating procedures, proper instrumentation and filling. Under these conditions an interappointment dressing with calcium hydroxide does not seem to influence outcome.

Epithelium and bacteria in periapical lesions

OBJECTIVE

The purpose of this study was to evaluate 50 human periapical lesions for bacteria and epithelium in a case study in dental practice.

STUDY DESIGN

Specimens were obtained from the extraction of 50 untreated teeth that had lesions attached to their apices. The specimens were histologically evaluated using serial sections.

RESULTS

Bacteria were found in all teeth, colonizing necrotic tissue in the main canal, dentinal tubules, or apical ramifications, and in the body of the periapical lesion in 18 abscesses or cysts. Twenty-one lesions were epithelialized; 14 abscesses, 20 granulomas, and 16 cysts were distinguished. In 18 root canals inflamed tissue was found in the apical part of the canal. A single foramen was present in 13 cases while apical ramifications were found in 37 cases.

CONCLUSIONS

Granulomas were most common, and most epithelialized lesions were cysts. Bacteria were only detected periapically in abscesses or cysts. Inflamed tissue was present in the apical root canal in one third of cases.

Is pulpitis painful?

AIM

To determine whether inflamed dental pulps progress to necrosis without pain.

METHODOLOGY

Records of 2,202 maxillary anterior teeth endodontically treated at the University of Michigan were collected. Records of teeth presenting with periapical radiolucencies but no response to vitality tests were examined further to determine, from the history, whether the patient had experienced pain or no pain from the involved tooth.

RESULTS

Approximately 40% of the teeth included gave no history of spontaneous or prolonged pain to a thermal stimulus. No statistically significant differences in the incidence of 'painless pulpitis' were related to either gender or tooth type. Patients aged >53 years experienced 'painless pulpitis' more often than patients <33 years.

CONCLUSIONS

Many teeth appear to progress to pulpal necrosis without the patient experiencing pain attributable to the pulp.

Prevalence of different periapical lesions associated with human teeth and their correlation with the presence and extension of apical external root resorption

AIM

The aim of this study was to determine the prevalence of various periapical pathologies and their association with the presence and extent of apical external inflammatory root resorption in human teeth.

METHODOLOGY

One hundred and four root apices from extracted teeth with periapical lesions were examined. Semi-serial sections of soft tissue lesions were stained with HE. The lesions were classified as noncystic or cystic, each with different degrees of acute inflammation: 0, 1, 2 and 3, increasing in severity. The root apices were analysed by SEM. External root resorption was classified according to site, as periforaminal or foraminal, and the extension of the resorbed area graded in increasing area as 0, 1, 2 or 3.

RESULTS

Cysts accounted for 24.5% of the samples, 84% of which were associated with marked inflammation. The most prevalent diagnosis was noncystic periapical abscess with varying degrees of severity (63.7%). Periapical granuloma was not a frequent finding. SEM analysis showed that 42.2% of the root apices had periforaminal resorption extending over 50% of their circumference. When the foraminal resorption was evaluated, 28.7% had resorption affecting >50% of the periphery. Only 8.9% of the samples showed no periforaminal or foraminal resorption.

CONCLUSIONS

In the sample of extracted teeth investigated, 24.5% of the periapical lesions were cysts. Most periapical lesions (84.3%) displayed acute inflammation, whether cystic or not. Periforaminal resorption was present in 87.3% of the cases, and foraminal resorption in 83.2%. Periforaminal and foraminal resorptions were independent entities. There was no association between external root resorption and the nature of the periapical lesions.

Localization and changes in superoxide dismutase immunoreactivity in rat pulp after tooth preparation

OBJECTIVE

To examine the distribution of superoxide in the uninflamed and inflamed dental pulp by characterizing the immunoreactivity of the detoxifying antioxidant enzymes, manganese and copper-zinc superoxide dismutases (MnSOD and CuZnSOD, respectively).

STUDY DESIGN

In 12 rats, mesial cavity preparations were made on the maxillary right first molar; left molars were unoperated controls. After 5 days, the rats were killed, and histologic sections were processed by using MnSOD and CuZnSOD immunoreactivity, and the extent of inflammation was evaluated on alternate sections stained with hematoxylin and eosin.

RESULTS

In the hematoxylin and eosin-stained sections, inflammation was consistent with round-cells: macrophages, lymphocytes, and plasma cells that coalesced into a distinct leukocytic "lesion", which obliterated portions of the underlying pulp. Both MnSOD and CuZnSOD immunoreactivity increased dramatically in inflammatory cells within the leukocytic lesion and in the tissue surrounding the lesion.

CONCLUSIONS

The findings suggest that the protective role of SOD increases within pulp cells that are undergoing inflammatory stimulation. SOD immunoreactivity may be an early indicator of stress in pulp.

Radiographic and microbiologic evaluation of posttreatment apical and periapical repair of root canals of dogs' teeth with experimentally induced chronic lesion

The objective of the present study was to evaluate radiographically and bacteriologically apical and periapical repair in dogs' teeth with induced chronic periapical lesions with the use of two different operative techniques (techniques 1 and 2). The study was conducted on 40 root canals of upper and lower premolars from two dogs aged approximately 12 months. Periapical lesions were induced by leaving the root canals exposed to the oral environment for 5 days and then sealing them with zinc oxide-eugenol for 45 days. After this period, radiographic examination revealed the occurrence of a radiolucent lesion and endodontic treatment was started. The two techniques did not differ in terms of chemomechanical preparation, final filling, or type of cement, but differed in terms of irrigating solution and the presence of an antibacterial dressing. Thus 4% to 6% hypochlorite and hydrogen peroxide (10 volumes) were used in technique 1 during chemomechanical preparation and an antibacterial dressing based on calcium hydroxide was applied between sessions, whereas Dakin's fluid (0.5% sodium hypochlorite solution) and a final filling with no antibacterial dressing were used in technique 2. After chemomechanical preparation, the root canals were filled with gutta-percha cones and Sealapex (Sealapex-Sybron, Kerr, Sao Paulo, Brazil), and the animals were killed 270 days after the final filling. Blocks were cut into 6-microns sections and stained by the Brown and Brenn method.(ABSTRACT TRUNCATED AT 250 WORDS)

Factors associated with endodontic treatment failures

Two hundred and thirty-six cases of endodontic treatment failures, none of which had advanced periodontal disease, postperforations, or root or crown fractures were analyzed clinically, radiographically, and histobacteriologically to determine the major factor(s) for treatment failures. It was found that there was a correlation between bacterial infection in the canal system and the presence of periradicular rarefaction in endodontic failures. This report provides evidence indicating that the major factors associated with endodontic failures are the persistence of bacterial infection in the canal space and/or the periradicular area and the presence of preoperative periradicular rarefaction. The apical extent of root canal fillings, i.e. underfilled, flush-filled, or overfilled, seems to have no correlation to treatment failures.

Tissue reaction to endodontic materials: methods, criteria, assessment, and observations

The purpose of this study was to develop methods and criteria for the testing of the biocompatibility of endodontic materials. One hundred twenty-one teeth from 12 baboons (Papio anubis) were used to test three sealers: AH26, Kerr pulp canal sealer, and Kloroperka N.O. Gutta-percha cones were used as solid core in all cases. Under disinfected conditions, access preparation was performed, and with working length approximately 1.0 mm short of the foramen, the instrumentation of the root canal was started, using sodium hypochlorite (1%) for irrigation. After the root canals were cleaned and shaped, they were obturated with gutta-percha cones and the sealer, and by lateral condensation technique. Histologic periapical reactions were evaluated at 1, 7, 30, 365, 730, and 1095 days. The methods and criteria used were adequate for ranking of the biocompatibility of the tested materials in the short and long periods. At short observation periods (1 to 7 days) AH26 caused severe reactions, and Kerr pulp canal sealer and Kloroperka N.O., moderate and mild reactions, respectively. At 2- and 3-year observation periods the ranking was AH26, mild; Kerr pulp canal sealer, moderate; and Kloropercha N.O., severe.

A comparison of erythromycin and cefadroxil in the prevention of flare-ups from asymptomatic teeth with pulpal necrosis and associated periapical pathosis

In a previous study by our group with patients having asymptomatic teeth with pulpal necrosis and an associated periapical radiolucent lesion (PN/PL), it was shown that prophylactic administration of penicillin V or erythromycin (high-dose, 1-day regimen) resulted in a low incidence of flare-up (mean = 2.2%) and a low incidence of swelling and pain not associated with flare-up. No hypersensitivity responses occurred, and gastrointestinal side effects were found primarily with the erythromycins. To ascertain whether a single-dose administration of a long-acting 1-gm tablet of the cephalosporin antibiotic cefadroxil would result in a similar outcome, the present study was undertaken with 200 patients having quiescent PN/PL. The patients were randomly given either cefadroxil or erythromycin (base or stearate). Evaluations of flare-up were done 1 day, 1 week, and 2 months after endodontic treatment. A 2.0% flare-up incidence was found, with no statistically significant differences for cefadroxil (1.0%), stearate (2.0%), or base (4.0%). No hypersensitivity responses occurred. Gastrointestinal side effects were found primarily with the erythromycins (19.0%). The results showed that a 1-gm, single-dose regimen of cefadroxil was as effective as erythromycin and penicillin in preventing flare-ups and serious sequelae. A comparative analysis of the data from our first study (no peritreatment antibiotics) and the pooled data from our last three investigations (including the current trial) showed that peritreatment antibiotic coverage significantly reduced flare-ups and serious sequelae after endodontic treatment of asymptomatic PN/PL (p less than 0.001).

Pulpal healing after luxation injuries and root fracture in the permanent dentition

Pulpal healing patterns were studied in a clinical material of 637 luxated and 95 root-fractured permanent incisors followed routinely for up to 11 years. It was found that pulpal healing patterns could generally be divided into 3 groups according to the degree of injury sustained by the pulp: little, moderate or severe. Thus after luxation injuries, pulp survival could be without radiographic change (PS), with pulp canal obliteration (PCO) or nonhealing (pulp necrosis (PN]. After root fracture, similar healing patterns could be observed: healing by hard tissue union of fragments (HT), by connective tissue union of fragments (CT) or by nonunion due to interposition of granulation tissue between fragments (GT) resulting from PN of the coronal fragment. In both trauma situations, healing or nonhealing could be determined by type of luxation injury, stage of root development and type of fixation used (forceful application of orthodontic bands vs. passively applied acid-etch fixation). Pulpal healing complications (PN or GT) were based on clinical findings (coronal discoloration, loss of pulpal sensibility) and radiographic findings (resorption processes of the lamina dura at the root apex or at the level of the root fracture). However, in both injury groups the same changes could also be seen to be intermediate steps in the pulpal healing process. Based on findings from these studies, hypotheses for the mechanics of pulpal healing are proposed as well as guidelines for acute and later treatment of dental luxations, root fractures and the diagnosis of healing complications.

A prospective randomized trial on efficacy of antibiotic prophylaxis in asymptomatic teeth with pulpal necrosis and associated periapical pathosis

A recent study from a private endodontic practice compared "prophylactic" antibiotic (high-dose, 1-day) regimens of penicillin V and erythromycin (base or stearate) for patients who had asymptomatic teeth with pulpal necrosis and associated periapical radiolucent lesions (PN/PL). A 2.2% flare-up incidence was found, with no statistically significant differences for penicillin (0.0%), base (2.9%), and stearate (3.8%). No hypersensitivity responses occurred, and gastrointestinal side effects were found primarily with the erythromycins (12.4%). To ascertain whether or not similar results would occur with student operators in a dental school clinic population, the current study was undertaken. One-hundred ninety-five patients with quiescent PN/PL were randomly given either penicillin V or erythromycin (base or stearate). A 2.6% flare-up incidence was found, with no statistically significant differences for penicillin (3.1%), base (1.5%), and stearate (3.1%). No hypersensitivity responses occurred, and GI side effects were found primarily with the erythromycins (17.7%). As can be seen, the results were very similar to those of the recent endodontic practice study. Hence, it can be concluded that the results of the previous endodontic practice study were not unique to any one clinician or method. A comparison was also made between the "prophylactic" penicillin group of the current study and the placebo control group of our previous dental school clinic, student operator study (in which the methods, population, and regimen were almost identical to those of the current study). The results showed that the "prophylactic" penicillin group had significant fewer flare-ups and non-flare-up-associated swelling and pain than did the placebo group. In view of these findings and those from studies from the literature in which "prophylactic" antibiotics were not used, it is our opinion that the antibiotic regimens used in the current study should be a component of clinical endodontic therapy for quiescent PN/PL.

A prospective randomized trial comparing periapical instrumentation to intracanal instrumentation in cases of asymptomatic pulpal-periapical lesions

To clarify the divergent viewpoints with respect to method of instrumentation in asymptomatic teeth with pulpal necrosis and associated periapical radiolucent lesions (PN/PL), this prospective study was undertaken. The subjects were 106 patients with quiescent cases of PN/PL. Alternately, 53 had periapical instrumentation and 53 had intracanal instrumentation. Prophylactic antibiotics were not administered but the patients were told to take an antibiotic at the first sign of swelling. Flare-ups, non-flare-up-associated swelling and pain, and cases in which there were no postoperative problems were evaluated at 1-day, at 1 week, and at 2 months. A 6.6% incidence of flare-up was found with no statistically significant difference between periapical instrumentation (7.5%) and intracanal instrumentation (5.7%). A 27.4% incidence of swelling was found with no statistically significant difference between periapical instrumentation (24.5%) and intracanal instrumentation (30.2%). A 43.4% incidence of pain was found, with no statistically significant difference between periapical instrumentation (15.1%) and intracanal instrumentation (47.2%). When moderate pain and severe pain were combined, the incidence was 21.7%, with no statistically significant difference between periapical instrumentation (15.1%) and intracanal instrumentation (28.3%). An incidence of patients having no postoperative problems of 41.5% was found, with no statistically significant difference between periapical instrumentation (47.2%) and intracanal instrumentation (35.8%). When flare-ups were combined with swelling, the incidence was 34.0%, with no statistically significant difference between periapical instrumentation (32.1%) and intracanal instrumentation (35.8%). When flare-ups were combined with pain, the incidence was 50.0%, with no statistically significant difference between periapical instrumentation (47.2%) and intracanal instrumentation (52.8%).(ABSTRACT TRUNCATED AT 250 WORDS)

Infectious flare-ups and serious sequelae following endodontic treatment: a prospective randomized trial on efficacy of antibiotic prophylaxis in cases of asymptomatic pulpal-periapical lesions

Without peritreatment antibiotics, infectious flare-ups (about 15% incidence) and serious sequelae follow endodontic treatment of asymptomatic teeth with necrotic pulps and associated periapical lesions. Antibiotics administered after endodontic treatment (4-day regimen) reduce the flare-up incidence to about 2%, but hypersensitivity responses, sensitization, resistant microbes, and drug-taking compliance are potential problems. To ascertain whether a specific prophylactic antibiotic (high-dose, 1-day regimen) would preferentially maintain this low flare-up incidence while overcoming antibiotic-related problems, 315 patients with quiescent pulpal necrosis and an associated periapical lesion were randomly given either penicillin V or erythromycin (base or stearate). Evaluations of flare-up after endodontic treatment were done at 1 day, 1 week, and 2 months. A 2.2% flare-up incidence was found, with no statistically significant differences for penicillin (0.0%), base (2.9%), and stearate (3.8%). No hypersensitivity responses occurred. Gastrointestinal side effects were found primarily with the erythromycins (12.4%). A comparative analysis of the data from our first study (no peritreatment antibiotics) and the pooled data from our last two investigations (including the current trial) showed that peritreatment antibiotic coverage significantly reduced flare-ups and serious sequelae after endodontic treatment (p less than 0.001).