Incidence of Cholesterol in Periapical Biopsies among Adolescent and Elderly Patients

Introduction

Cholesterol clefts are common histologic findings in periapical biopsies; they have a reported incidence in periapical periodontitis of up to 44%. Cholesterol crystals are also recognized in advanced atherosclerotic plaques in humans. Male sex, genetic abnormalities, and age have been associated with advanced atherosclerotic lesions. Among these nonmodifiable risk factors, age is the most dominant. The aim of the study was to evaluate if age is also linked to cholesterol deposition in periapical periodontitis.

Methods

The database of biopsy reports obtained between 2006 and 2009 was searched for specimens diagnosed as radicular cysts or periapical granulomas. Only data relating to biopsies obtained from adolescent (13–21 years old) and elderly (over 60 years old) patients were selected. The biopsies were examined by a pathologist under a light microscope (Zeiss, Jena, Germany) at magnifications of 40×–200×. The available material was scanned for the presence of cholesterol clefts and foamy cells in radicular cysts and granulomas.

Results

A total of 41 specimens were collected in the adolescent group and 48 specimens in the elderly group over a 4-year period. A higher incidence of cholesterol was found in the elderly group compared with that in the adolescent group (odds ratio = 6.857).

Conclusions

The highly significant incidence of cholesterol deposits in periapical biopsies among elderly patients may be a possible cause for the lack of repair. The mechanism for cholesterol accumulation is probably similar to the process leading to atherosclerosis and coronary artery disease. Statin administration may be advantageous for the treatment of persistent lesions. A clinician should be aware of the risk for persistent lesions after endodontic treatment in elderly patients.     

Distribution of Mast Cells and Macrophages and Expression of Interleukin-6 in Periapical Cysts

Introduction

Mast cells and macrophages are important components of the inflammatory infiltrate found in inflammatory periapical diseases. Several cytokines participate in the mechanisms of inflammation, tissue repair, and bone resorption associated with periapical cysts. The aim of the present study was to evaluate the distribution of mast cells and macrophages and the expression of interleukin-6 (IL-6) in periapical cysts.

Methods

Thirty periapical cysts were selected for the study, and clinical, demographic, and gross information from the cases was obtained from the laboratory records. Five-micrometer sections stained with hematoxylin-eosin were reviewed for analysis of the microscopic features of the cysts, and 3-μm sections on silanized slides were used for immunohistochemical reactions with anti-tryptase, anti-CD68, and anti–IL-6.

Results

There was no statistically significant difference in the mean number of mast cells and macrophages when comparing superficial and deep regions of the fibrous capsule of the cysts. Mean number of mast cells on the superficial region of the fibrous capsule was higher in cysts showing intense superficial inflammation and exocytosis. Macrophages were more commonly found in areas showing IL-6 expression, and IL-6 was less expressed in deep regions of the fibrous capsule in cysts showing greater gross volume.

Conclusions

The results reinforced the participation of mast cells and macrophages in the pathogenesis of periapical cysts and suggested that IL-6 is not the major bone resorption mediator in larger periapical cysts.     

Orthokeratinized Odontogenic Cysts Presenting as a Periapical Lesion: Report of a Case and Literature Review

Introduction

Inflammatory cysts, granulomas, abscesses, and fibrous scars represent most periapical radiolucencies. However, other less common lesions, such as orthokeratinized odontogenic cysts (OOCs), can be found at this region, and they deserve to be discussed because the prognosis for an OOC is different from that expected for the ordinary inflammatory periapical diseases.

Methods

An interesting case of OOC associated with a nonvital tooth in a 40-year-old woman is described. After a previous clinical diagnosis of a radicular cyst, the tooth was extracted, and the lesion was enucleated and submitted to microscopy examination.

Results

Because of the detection of an orthokeratinized epithelium lining, a diagnosis of OOC was concluded. After 2 years of periodic follow-up, no signs of recurrence were detected.

Conclusions

The presence of keratin in radicular lesions must be carefully evaluated to eliminate the diagnosis of lesions with more aggressive behavior, such as an OOC or even a keratocystic odontogenic tumor. Hence, histopathologic examination is mandatory to confirm the type of lesion and to differentiate other pathologic conditions, therefore establishing patients' prognoses precisely.     

Expression of Heat Shock Proteins in Periapical Granulomas

Introduction

Cells from virtually all organisms respond to a variety of stresses by the rapid synthesis of a highly conserved set of polypeptides termed heat shock proteins (HSPs). HSPs protect cells under adverse conditions such as infection, inflammation, and disease. We hypothesize that endodontic infection might result in an imbalance in the expression of heat shock genes, accounting for different clinical outcomes in periapical lesions.

Methods

We analyzed the expression of 44 HSPs genes using a pathway-specific real-time polymerase chain reaction array in 93 human periapical granulomas and 24 healthy periodontal ligament tissues collected postoperatively. Observed variations in the expression of HSP genes were also analyzed based on the classification of periapical granulomas as active or inactive. In addition, U937 cells were differentiated into macrophages, infected with different concentrations of purified Escherichia coli lipopolysaccharide (LPS), and used as templates for the HSP gene array. Protein expression was assessed by immunohistochemistry.

Results

The expression of HSP genes was significantly increased in granulomas compared with healthy periodontal ligament (P < .00001). Among the 44 HSP genes, DNAJC3, HSPA4, HSPA6, and HSPB1 showed the highest expression levels in both granulomas and LPS-treated macrophages. DNAJC3, HSPA6, and HSPB1 were highly expressed in active lesions, whereas HSPA4 expression was higher in inactive lesions (P < .005). Higher concentrations of LPS led to increased HSP expression in macrophages (P < .0001). Immunocytochemistry confirmed the expression and colocalization of HSPB1 and HSPA6 proteins in the cytoplasm of LPS-infected macrophages.

Conclusions

The observed differential expression patterns of HSPs in periapical granulomas and LPS-infected macrophages suggest that HSP genes and proteins are involved in periapical lesion development and may account for different clinical outcomes. Understanding the role of the heat shock response might provide additional insights into the process of periapical lesion development.     

Mesenchymal Stem Cells as Active Prohealing and Immunosuppressive Agents in Periapical Environment: Evidence from Human and Experimental Periapical Lesions

Introduction

Previous studies describe contrasting molecular profiles of active and inactive periapical granulomas characterized by distinct expression of cytokines, osteoclastogenic factors, and wound healing markers. Although the molecular mechanisms underlying such a dichotomy remain unknown, in this study we investigated the potential involvement of mesenchymal stem cells (MSCs) in determining human and murine periapical lesion activity and outcomes.

Methods

Periapical granulomas (n = 83) and control samples (n = 24) were comparatively assessed for the expression levels of 11 mesenchymal stem cell (MSC) markers using real-time polymerase chain reaction. Experimental periapical lesions induced in mice were evaluated for MSC marker expression and the effects of AMD3100 treatment on lesion outcomes.

Results

MCS marker expression was prevalent in periapical granulomas compared with that in controls, whereas CD29, CD73, CD90, CD146, CD166, NANOG, Stro-1, and CXCR4 expressions were higher in inactive than in active lesions. Experimental periapical lesion inactivity was also associated with an increased expression of MSC markers. The inhibition of MSC mobilization to the periapex by AMD3100 resulted in increased lesion sizes; decreased expression of MSCs and wound healing markers; and increased expression of interleukin 1 beta (IL-17β), interleukin 17 (IL-17), tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and nuclear factor kappa-B ligand (RANKL).

Conclusions

Our results show that MSC markers are overexpressed in inactive human and experimental periapical lesions and that MSC mobilization results in the attenuation of experimental lesion progression associated with immunosuppressive and prohealing mechanisms.     

Comparative Expression of CD34, Intercellular Adhesion Molecule-1, and Podoplanin and the Presence of Mast Cells in Periapical Granulomas,Cysts, and Residual Cysts

Introduction

The aim of the present study was to compare the immunoexpression of CD34, intercellular adhesion molecule-1 (ICAM-1), and podoplanin and the presence of mast cells with clinical, demographic, radiologic, and histologic features from periapical granulomas, periapical cysts, and residual cysts.

Immunoexpression of Interleukin 17 in Apical Periodontitis Lesions

Introduction

Interleukin (IL)-17 expression has been detected in apical periodontitis lesions, but its role in the disease process remains unclear. The present study compared the expression of IL-17 in periradicular cysts and granulomas and evaluated the association of this cytokine with clinical and radiographic findings.

Methods

Apical periodontitis lesions (18 cysts and 20 granulomas) were obtained from 38 patients subjected to periradicular surgery. Some clinical, radiographic, and cone-beam computed tomographic features were recorded. Silanized slides containing paraffin sections were used for the immunohistochemical reactions using anti–IL-17 antibody. Image analysis was performed using an optical microscope, and each sample was divided into 5 high-power fields, which were evaluated for the expression of IL-17 in the epithelium and connective tissues. Results were evaluated for correlations with the lesion size and the occurrence of symptoms and sinus tract.

Results

Expression of IL-17 was significantly higher in cysts than in granulomas (P = .02). Among the periradicular cysts, a thin epithelium showed significantly increased labeling for IL-17 when compared with a hyperplastic epithelium (P = .003). IL-17 expression was usually associated with focal accumulations of polymorphonuclear leukocytes. No association of IL-17 expression with symptoms, sinus tract, or lesion size was observed (P > .05).

Conclusions

The present study reinforces the notion that IL-17 may take part in the pathogenesis of apical periodontitis lesions. A role in the exacerbation of chronic inflammation and cyst formation is suspected. Further studies are required to shed light on the specific functions of IL-17 in periradicular inflammatory processes.     

Evaluation of the Reliability and Accuracy of Using Cone-beam Computed Tomography for Diagnosing Periapical Cysts from Granulomas

Introduction

The purpose of this study was to evaluate the reliability and accuracy of cone-beam computed tomographic (CBCT) imaging against the histopathologic diagnosis for the differential diagnosis of periapical cysts (cavitated lesions) from (solid) granulomas.

Methods

Thirty-six periapical lesions were imaged using CBCT scans. Apicoectomy surgeries were conducted for histopathological examination. Evaluator 1 examined each CBCT scan for the presence of 6 radiologic characteristics of a cyst (ie, location, periphery, shape, internal structure, effects on surrounding structure, and perforation of the cortical plate). Not every cyst showed all radiologic features (eg, not all cysts perforate the cortical plate). For the purpose of finding the minimum number of diagnostic criteria present in a scan to diagnose a lesion as a cyst, we conducted 6 receiver operating characteristic curve analyses comparing CBCT diagnoses with the histopathologic diagnosis. Two other independent evaluators examined the CBCT lesions. Statistical tests were conducted to examine the accuracy, inter-rater reliability, and intrarater reliability of CBCT images.

Results

Findings showed that a score of ≥4 positive findings was the optimal scoring system. The accuracies of differential diagnoses of 3 evaluators were moderate (area under the curve = 0.76, 0.70, and 0.69 for evaluators 1, 2, and 3, respectively). The inter-rater agreement of the 3 evaluators was excellent (α = 0.87). The intrarater agreement was good to excellent (κ = 0.71, 0.76, and 0.77).

Conclusions

CBCT images can provide a moderately accurate diagnosis between cysts and granulomas.     

Outcomes of Hospitalizations Attributed to Periapical Abscess from 2000 to 2008: A Longitudinal Trend Analysis

Introduction

Root canal therapy is a highly successful in-office treatment and preventive measure against periapical abscesses. Left untreated, periapical abscesses can have serious consequences that can lead to hospitalization. This study observes the trends of hospitalizations attributed to periapical abscesses.

Methods

A retrospective analysis of the Nationwide Inpatient Sample (years 2000–2008) was used; we selected cases with a primary diagnosis of a periapical abscess with/without sinus involvement. The demographic characteristics and outcomes were examined. Each individual hospitalization was the unit of analysis.

Results

During the 9-year study period, a total of 61,439 hospitalizations were primarily attributed to periapical abscesses in the United States. The average age was 37 years, and 89% of all hospitalizations occurred on an emergency/urgent basis. The mean length of stay was 2.96 days, and a total of 66 patients died in hospitals. Medicare, Medicaid, and private insurance plans paid for 18.7%, 25.2%, and 33.4% of hospitalizations, respectively. Uninsured patients accounted for 18.5% of hospitalizations. Significant predictors that influenced both hospital charges and length of stay included age, race, insurance status, a periapical abscess with sinus involvement, geographic region of country, the Charlson comorbidity index, and the year of study (P < .05).

Conclusions

The current study highlights the increasing burden of hospitalization of patients with periapical abscesses over a 9-year study period from 2000 to 2008. The high-risk groups likely to seek a hospital setting for the treatment of periapical abscesses were identified as were groups associated with higher hospital charges and a longer length of stay.     

Immunohistochemical Analysis of Galectins-1, -3, and -7 in Periapical Granulomas,Radicular Cysts,and Residual Radicular Cysts

Introduction

Galectins play important roles in immunoinflammatory responses, but their participation in the development of periapical lesions remains unclear. This study aimed to evaluate the expressions of galectins-1, -3, and -7 in periapical lesions, correlating them with the intensity of the inflammatory infiltrate and the pattern of the cystic epithelium.

Histochemical Localization of Dickkopf-1 in Induced Rat Periapical Lesions

Introduction

The purpose of this study was to evaluate the expression of Dickkopf-1 (DKK-1), a secreted antagonist of the Wnt (wingless)/beta-catenin signaling pathway, during the development of periapical lesions in rats.

Methods

Periapical lesions were induced in Wistar rats by occlusal exposure of the pulp of their mandibular first molars. The animals were sacrificed randomly at 0, 7, 14, 21, and 28 day after pulpal exposure. Jaws containing the first molar were obtained and routinely prepared for histologic, immunohistochemical, and enzyme histochemical double immunofluorescence analyses. Data were analyzed using 1-way analysis of variance and Pearson correlation test.

Results

The expansion of the area of periapical lesions was visible from days 7–21 and slowed down thereafter. A few DKK-1- and receptor activator of nuclear factor kappa B ligand (RANKL)-positive cells and osteoclasts were observed on day 7. All positive samples peaked in number on day 14. The expression levels of DKK-1 and RANKL and the number of osteoclasts decreased on days 21 and 28. DKK-1 expression was positively correlated with RANKL expression and osteoclast number from days 7–28.

Conclusions

DKK-1 expression was up-regulated during periapical lesion development. DKK-1 may be associated with the inflammatory response and bone resorption in periapical lesions.     

10-Year Follow-up of Calcifying Odontogenic Cyst in the Periapical Region of Vital Maxillary Central Incisor

Introduction

Radiographic images may lead to misinterpretations of lesions of endodontic and nonendodontic origin. This report describes a case of a 10-year follow-up of a calcifying odontogenic cyst (COC) in the periapical region of a vital maxillary central incisor in a 9-year-old boy.

Methods

The patient revealed a history of a swelling in the periapical area of tooth #9. The patient denied any dental trauma or history of pain. Clinical examination revealed no mobility, but there was discrete discomfort when horizontal pressure was applied. Pulp vitality was present in all maxillary anterior teeth. Radiographs revealed an oval radiolucent lesion in the periapical region of maxillary central incisor. The therapeutic option was enucleation of the periapical lesion and histologic examination of the specimen. Microscopic findings suggested the diagnosis of a COC.

Results

At a follow-up visit 10 years after surgery, panoramic and periapical radiographs showed new bone formation; the patient did not have any pain, and pulp vitality was maintained in all teeth in this area.

Conclusions

A COC should be part of the differential diagnosis of other jaw lesions, such as apical periodontitis. The definitive diagnosis of a COC can only be made after microscopic evaluation of the specimen. The follow-up is a helpful reference because it confirms the survival of pulp tissue and no recurrence of the COC.     

Periapical Status Related to the Quality of Coronal Restorations and Root Fillings in a Korean Population

Introduction

The purpose of this study was to assess the prevalence of apical periodontitis in root canal–treated teeth from the Korean population and to evaluate the relationship between the quality of root canal fillings and coronal restorations and the periapical status of these teeth.

Methods

Full-mouth periapical radiographs at the Dental Hospital of Yonsei University, Seoul, South Korea, were examined. A total of 1030 endodontically treated teeth restored with full veneer crown–type restorations were evaluated by 2 independent examiners. Teeth were classified as healthy or diseased according to the periapical status. The quality of endodontic treatment and coronal restorations were also classified via radiographic and clinical evaluation. The data were analyzed using the chi-square test and logistic regression.

Results

Forty-one percent of all endodontically treated teeth were classified as diseased. Approximately 35.6% of the teeth had endodontic treatments that were rated as adequate. The diseased teeth rate for cases with adequate endodontic treatment was 24.5%, which was significantly lower when compared with teeth with inadequate endodontic treatment (49.9%). The number of teeth with adequate coronal restorations was 706 (68.5%). Teeth with adequate coronal restorations had a significantly decreased prevalence of diseased teeth (34.7%) compared with teeth with inadequate coronal restorations (54.3%). Teeth with both adequate root fillings and restorations showed a significantly better outcome (82.3%) than the others, and teeth with both inadequate root fillings and restorations showed a significantly worse outcome (41.2%) than the others.

Conclusions

Data from this Korean population showed a relatively high prevalence of apical periodontitis. The quality of endodontic treatment and coronal restorations were of equal importance and were strong independent predictors of the periapical status.     

Expression and immunohistochemical localization of leptin in human periapical granulomas

Background

Leptin, initially described as an adipocyte-derived hormone to regulate weight control, is expressed in normal and inflamed human dental pulp, being up-regulated during pulp experimental inflammation. Leptin receptor (LER) has been identified in human periapical granulomas. The aim of this study was to analyze and characterize the expression of leptin in human periapical granulomas.

Material and Methods

Fifteen periapical inflammatory lesions were obtained from extracted human teeth and teeth which underwent periapical surgery. After their morphological categorization as periapical granulomas and gradation of the inflammatory infiltrate, they were examined by immunohistochemistry using human leptin policlonal antibodies. Leptin mRNA expression was also determined by quantitative real-time PCR (qRT-PCR) and the amount of leptin protein was analyzed by immunoblot.

Results

All periapical lesions exhibited the characteristic of chronic granulomatous inflammatory process with inflammatory infiltrate grade III. Leptin+ cells were detected in 13 periapical granulomas (86.6%). The median number of Leptin+ cells in periapical granulomas was 1.70 (0.00-7.4). Amongst the inflammatory cells in the periapical granulomas, only macrophages were reactive to leptin antibodies. Western blot analysis revealed the presence in all samples of a protein with apparent molecular weight of approximately 16 kDa, corresponding to the estimated molecular weights of leptin. The expression of leptin mRNA was confirmed by qRT-PCR analysis and the size of the amplified fragment (296 bp for leptin and 194 bp for cyclophilin) was assessed by agarose gel electrophoresis.

Conclusions

For the first time, it has been demonstrated that human periapical granuloma expresses the adipokine leptin. Key words: Apical granuloma, dental pulp, endodontics, leptin, leptin receptor, immune system, immunohistochemistry, periapical inflammatory response.     

Comparison of Endodontic Diagnosis and Treatment Planning Decisions Using Cone-beam Volumetric Tomography Versus Periapical Radiography

Introduction

Accurate and confident treatment planning is an essential part of endodontic practice. Periapical radiographs have been used to aid in the diagnosis of pathology and to help establish an appropriate treatment strategy. Recently, a new imaging modality, cone-beam volumetric tomographic (CBVT) imaging, has been shown to be a useful tool in a number of endodontic applications. The aim of this study was to compare the relative value of preoperative periapical radiographs and CBVT scanning in the decision-making process in endodontic treatment planning.

Methods

Thirty endodontic cases completed in a private endodontic practice were randomly selected to be included in this study. Each case was required to have a preoperative digital periapical radiograph and a CBVT scan. Three board-certified endodontists reviewed the 30 preoperative periapical radiographs. Two weeks later, the CBVT volumes were reviewed in random order by the same evaluators. The evaluators were asked to select a preliminary diagnosis and treatment plan based solely on their interpretation of the periapical and CBVT images. Diagnosis and treatment planning choices were then compared to determine if there was a change from the periapical radiograph to the CBVT scan.

Results

A difference in treatment plan between the 2 imaging modalities was recorded in 19 of 30 cases (63.3%, P = .001), 17 of 30 cases (56.6%, P = .012), and 20 of 30 cases (66.7%, P = .008) for examiners 1, 2, and 3, respectively.

Conclusions

Under the conditions of this study, preoperative CBVT imaging provides additional information when compared with preoperative periapical radiographs, which may lead to treatment plan modifications in approximately 62% of the cases.     

The Dynamics of Periapical Lesions in Endodontically Treated Teeth That Are Left without Intervention: A Longitudinal Study

Introduction

The long-term dynamics of periapical lesions in endodontically treated teeth is not fully elucidated, thus presenting a clinical dilemma regarding the need for an intervention. The aim of the study was to retrospectively evaluate the long-term dynamics of periapical lesions that were left without intervention in endodontically treated teeth.

Methods

Periapical status surveys of patients treated in a public dental clinic were retrospectively evaluated for the presence of periapical lesions in endodontically treated coronally restored teeth. The dynamics of the included periapical lesions was evaluated based on the periapical index (PAI) score changes between 2 consecutive periapical surveys of at least a 4-year interval. The influence of various factors on lesion dynamics was statistically evaluated.

Results

The study cohort consisted of 74 patients with a total of 200 endodontically treated teeth having periapical lesions that fulfilled the inclusion criteria. Fifty-seven (28.5%) lesions remained unchanged, 103 (51.5%) lesions worsened (PAI score increased), and 40 (20%) lesions improved (PAI score decreased). Poor root canal filling and poor restoration were found to adversely affect the long-term dynamics of the periapical lesions (P < .05). Age, sex, and the presence of a post had no statistically significant influence on lesion dynamics (P > .05).

Conclusions

Poor root canal filling and poor restoration may adversely affect the long-term dynamics of periapical lesions that are left without intervention in endodontically treated teeth. Therefore, in cases of poor root canal filling or poor restoration, further intervention may be indicated.     

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.     

Comparative immunohistochemical identification and relative distribution of immunocompetent cells in sections of frozen or formalin-fixed tissue from human periapical inflammatory lesions

Abstract The presence of immunocompetent cells (B, Th/i and Ts/c cells and macrophages) and the ratios of these cell populations in periapical lesions (radicular granulomas, radicular cysts and apical scars) were demonstrated immunohistochemically using paraffin and cryo-sections. Thirty-four human periapical lesions were examined for the presence of immunocompetent cells by monoclonal antibodies and the biotin-avidine-horse-radish peroxidase method. The T/B cell ratio of radicular cysts was significantly higher than that of both radicular granulomas and apical scars, and the average number of Th/i cells was greater than that of Ts/c cells in the radicular granulomas. However, no significant difference was found between radicular cyst and apical scar. The number of macrophages in radicular granulomas was significantly higher than that of the other lesions. These findings suggested that periapical lesions develop as a result of both humoral and cell-mediated immunological response and indicated that the ratios of immunocompetent cells are different in the different types of periapical lesion.