Periapical lesion development in rats inhibited by dexamethasone

Resolution of a periapical lesion in an autoimmune pancreatitis patient treated with long-term low-dose glucocorticoids: a case report

BACKGROUND

Patients diagnosed with an autoimmune disease are often systemically medicated with glucocorticoids. Autoimmune pancreatitis (AIP) Type 1 is considered a rare autoimmune disease, which is very well responsive to glucocorticoids and hence can be treated optionally on a long-term basis using low dose of the drug. Apical lesions of root canal-treated teeth can be solved by retreatment of the preexisting root canal obturation or via surgical approaches.

CASE PRESENTATION

This case report relates to a 76-year-old male patient, whose symptomatic acute apical periodontitis was treated nonsurgically by root canal treatment. However, overtime both roots of tooth 46 were associated with asymptomatic apical lesions. Despite progression of the lesions, due to a painless situation, the patient refrained from proceeding with any further treatment options after explaining the pathological pathway with all its consequences. A few years later the patient was prescribed 2.5 mg glucocorticoid prednisone daily for long-term therapy due to an AIP Type 1. Six years later under strict glucocorticoid therapy the apical lesions healed nearly completely and the patient remained free of symptoms without any further interventions.

CONCLUSIONS

These observations suggest that prospective clinical studies are required to further elucidate the potential healing effect of systemic long-term low-dose glucocorticoid medication on lesions of endodontic origin.

Periapical lesions in two inbred strains of rats differing in immunological reactivity

AIM

To investigate the influence of strain differences in immune responses on the pathogenesis of experimental periapical lesions in Dark Agouti (DA) and Albino Oxford (AO) inbred strains of rats.

METHODOLOGY

Periapical lesions were induced in male DA and AO rats by pulp exposure of the first mandibular right molars to the oral environment. Animals were killed 21 days after pulp exposure. The mandibular jaws were retrieved and prepared for radiographic, pathohistological, immunohistochemical analysis, real-time PCR and flow cytometry. Blood samples and the supernatant of periapical lesions were collected for measurement of cytokines and oxidative stress marker levels. Statistical analysis was performed using the Kruskal-Wallis H and Mann-Whitney U non-parametric tests or parametric One-Way anova and Independent Samples T-test to determine the differences between groups depending on the normality of the data. A significant difference was considered when p values were <.05.

RESULTS

DA rats developed significantly larger (p < .05) periapical lesions compared to AO rats as confirmed by radiographic and pathohistological analysis. The immunohistochemical staining intensity for CD3 was significantly greater in periapical lesions of DA rats compared to AO rats (p < .05). In DA rats, periapical lesions had a significantly higher (p < .05) percentage of CD3+ cells compared to AO rats. Also, the percentage of INF-γ, IL-17 and IL-10 CD3+CD4+ cells was significantly higher in DA rats (p < .05). DA rats had a significantly higher Th17/Th10 ratio. RT-PCR expression of IL-1β, INF-γ and IL-17 genes was significantly higher in periapical lesions of DA compared to AO rats (p < .05). The receptor activator of nuclear factor kappa-Β ligand/osteoprotegerin ratio was higher in DA compared to AO rats with periapical lesions (p < .05). Systemic levels of TNF-α and IL-6 were significantly higher in DA compared to AO rats (p < .05). Levels of lipid peroxidation measured as thiobarbituric acid reactive substances and reduced glutathione were significantly higher (p < .05) in the supernatant in the periapical lesions of DA rats.

CONCLUSION

After pulp exposure, DA rats developed much larger periapical lesions compared to AO rats. Genetically determined differences in immunopathology have been demonstrated to be a significant element defining the severity of periapical lesions.

Celecoxib treatment dampens LPS-induced periapical bone resorption in a mouse model

AIM

To evaluate the efficacy of selective and nonselective inhibitors of cyclooxygenase-2 enzymes in the treatment of experimental apical periodontitis induced by bacterial lipopolysaccharide (LPS) in vivo in a mouse model.

METHODOLOGY

Thirty-six C57BL/6 mice were used. After access cavity preparation, a solution containing E. coli LPS (1.0 µg µL^-1 ) was inoculated into the root canals of the mandibular and maxillary right first molars (n = 72) After 30 days, apical periodontitis was established and the animals were systemically treated with celecoxib, a selective COX-2 inhibitor (15 mg kg^-1 ), or indomethacin, a nonselective COX-2 inhibitor (5 mg kg^-1 ), for 7 and 14 days. Blocks containing teeth and bone were removed for histopathological and histometric analyses (haematoxylin and eosin), evaluation of osteoclasts numbers (tartrate-resistant acid phosphatase enzyme - TRAP) and immunohistochemistry for RANK, RANKL and OPG. Gene expression was performed using reverse transcription and real-time polymerase chain reaction (qRT-PCR) for RANK, RANKL, OPG, TRAP, MMP-9, cathepsin K and calcitonin receptor. Histopathological, histometric, TRAP, immunohistochemistry and qRT-PCR data were evaluated using Kruskal-Wallis followed by Dunn's test (α = 0.05).

RESULTS

Systemic administration of celecoxib for 7 and 14 days prevented periapical bone resorption (P < 0.0001), differently from indomethacin that exacerbated bone resorption at 7 days (P < 0.0001) or exerted no effect at 14 days (P = 0.8488). Celecoxib treatment reduced osteoclast formation in apical periodontitis, regardless of the period of treatment (P < 0.0001 for 7 days and P = 0.026 for 14 days). Administration of celecoxib or indomethacin differentially modulated the expression of genes involved in bone resorption. At 7 days, celecoxib and indomethacin treatment significantly inhibited expression of mRNA for cathepsin K (P = 0.0005 and P = 0.016, respectively) without changing TRAP, MMP-9 and calcitonin receptor gene expression. At 14 days, celecoxib significantly inhibited expression of mRNA for MMP-9 (P < 0.0001) and calcitonin receptor (P = 0.004), whilst indomethacin exerted no effect on MMP-9 (P = 0.216) and calcitonin receptor (P = 0.971) but significantly augmented cathepsin K gene expression (P = 0.001).

CONCLUSIONS

The selective COX-2 inhibitor celecoxib reduced osteoclastogenic signalling and activity that dampened bone resorption in LPS-induced apical periodontitis in mice, with greater efficacy than the nonselective inhibitor indomethacin.

Influence of immunosuppression on the progression of experimental periodontitis and on healthy periodontal tissue: A rat in vivo study

Background. The potent anti-inflammatory and immunosuppressive properties of glucocorticoids (GCs) might influence the progression of some disorders, such as periodontitis. Hence, this study aimed to investigate the influence of dexamethasone (DEX) on the alveolar bone loss (ABL) of healthy and periodontally compromised molars in rats.

Methods. Thirty male rats were randomly assigned to two groups: physiological saline solution (PSS) and DEX. The animals received subcutaneous injections of either 0.5 mL of PSS) (group PSS) or 2 mg/kg of DEX (group DEX) from one day before experimental periodontitis (EP) induction until euthanasia. EP was induced through ligature placement around the mandibular lower first molars at day 0. Contralateral molars remained unligated. Ten animals per period were euthanized on days 3, 7, and 14. Morphometric analysis was performed to access the ABL. Data were statistically analyzed with ANOVA followed by post hoc Tukey tests (P ≤ 0.05).

Results. Higher ABL was observed in both groups on days 7 and 14 than on day 3 (P ≤ 0.05). Concerning periodontitis, higher ABL was observed in group DEX on days 3, 7, and 14 days than group PSS at the same time intervals (P ≤ 0.05). Also, even in the contralateral unligated molars, group DEX exhibited higher ABL on days 3, 7, and 14 days than group PSS at the same time intervals (P ≤ 0.05).

Conclusions. Collectively, it can be concluded that DEX aggravates EP and induces spontaneous ABL in the healthy periodontium.

A Mouse Model for Studying the Development of Apical Periodontitis with Age

Older age is associated with reduced immune function. Our aim was to study how age affects the development of apical periodontitis (AP). AP was induced in two age groups of mice (young vs. adult). Histological samples were stained by Hematoxylin Eosin, Brown and Brenn, and Tartrate-Resistant Acid Phosphatase. In addition, the samples were scanned by Micro-Computerized-Tomography (micro-CT) to evaluate apical constriction and periapical lesion size. Cell density in the periapical region was computationally assessed. Moreover, lesion immune cell populations were characterized by flow cytometry and immunofluorescence. The young group presented more canals with necrotic radicular pulp compared to the adults. There was no difference in bacteria location in the canals between the groups. Apical constriction size was larger in the young mice compared to the adults. The periapical cell density was higher in the young group, while the dominant immune cells in the lesions were neutrophils, which also exhibited the highest young/adult ratio. Immunofluorescence demonstrated neutrophils in the lesion. More osteoclasts were present in the lesions of the young mice, in correlation to the higher volume of bone resorption in this group. Overall, we conclude that the immune reaction to AP stimuli was attenuated in the adult mice compared to the young.

Effect of Periapical Diseases in Development of MRONJ in Immunocompromised Mouse Model

Objectives

This study aimed to assess the effect of zoledronic acid on an immunocompromised mice model with periapical disease.

Materials and Methods

Thirty C57BL/6N mice were randomly divided into three groups (N = 10). All animals were subjected to bilateral ovariectomy (OVX) and then treated with saline (Veh), zoledronic acid (ZA), or concomitant zoledronic acid and dexamethasone (ZA/Dx) for 12 weeks. Eight weeks after starting drug administration, pulpal exposure was conducted on the lower left first molar. Four weeks after pulpal exposure, all mice were sacrificed and the mandibles were collected for radiological and histological examinations.

Results

Microcomputed tomography (μ-CT) examination showed significantly reduced periapical bone resorption in the ZA/Dx group and decreased periodontal bone resorption in both ZA and ZA/Dx groups. Higher bone mineral density (BMD) and strengthened microstructure were found in ZA and ZA/Dx groups. More empty lacunae were found in ZA and ZA/Dx groups.

Conclusions

Apical periodontitis aggravates MRONJ under immunocompromised circumstances. Concurrent use of ZA and steroids inhibits alveolar bone resorption but increases the risk of developing MRONJ.

Prevalence of Apical Periodontitis in Patients with Inflammatory Bowel Diseases: A Retrospective Clinical Study

AIM

We evaluated the prevalence of apical periodontitis (AP) and the oral health status in patients with inflammatory bowel diseases (IBDs) treated with immunomodulators, with particular attention to biologic medications (BMs).

METHODS

One hundred ten patients, 49 men and 61 women (average age, 46 ± 13.8 years), from the Gastroenterology Unit of the University Hospital with IBDs who were treated with BMs or corticosteroids were included in the study. One hundred ten patients who registered for a dental check-up at the Dental Clinic were matched for age, sex, and physical characteristics with the study group without systemic diseases and not taking medications who were the control. Patients underwent a complete oral, dental, and radiographic examination. Decayed, missing, and filled teeth and periapical index score indexes were recorded. Student t test, χ², and Mann-Whitney U test were used as appropriate.

RESULTS

The prevalence of AP was 64% in IBD patients and 59% in the control; according to the gender-stratified analysis, the difference was not significant among the male groups, whereas the number of teeth with AP was significantly higher in female patients with IBDs than in the controls (P ≤ .05). The prevalence of AP in patients treated with BMs was 65%; women showed 69% higher risk for AP and presented a significantly higher number of teeth with AP (P ≤ .05). Decayed, missing, and filled teeth index was similar in both groups, whereas patients with IBDs had a higher periapical index score than the controls.

CONCLUSIONS

Women with IBDs and taking immunomodulators had a higher prevalence of AP. All patients with IBDs had larger lesions than healthy subjects. These data emphasize the influence of the status of the immune system in the onset of AP and the need for further studies to confirm these findings.

Role of Periapical Diseases in Medication-Related Osteonecrosis of the Jaws

Objective

The present study aimed to investigate the role of periapical diseases in inducing medication-related osteonecrosis of the jaws (MRONJ) using an ovariectomized (OVX) mice model.

Materials and Methods

Twenty C57BL/6N female mice were randomly assigned to two groups. All mice were subjected to bilateral ovariectomy and then treated with oncologic dose of zoledronic acid (ZA) or vehicle for twelve weeks. Eight weeks after commence of drug administration, a pulpal exposure (PE) operation was performed on the first right lower molar to induce periapical periodontitis; the contralateral non-PE tooth was used as control. All animals were sacrificed four weeks after pulpal exposure, and the mandibles were harvested for radiological and histomorphometrical analysis.

Results

Micro computed tomography (μ-CT) examination demonstrated that periapical diseases significantly increased alveolar bone resorption, and the resorption was greatly attenuated by ZA treatment. Concurrent ZA therapy significantly increased bone density and histological osteocyte necrosis in the presence of periapical lesions.

Conclusion

ZA treatment reduced bone absorption resulting from periapical disease but increased the risk of developing MRONJ in the ovariectomized mouse model.

Expression of a cytokine, interleukin-23, in experimental periapical lesions

AIM

To investigate the expression of interleukin (IL)-23, a new member of the IL-12 family, in experimental periapical lesions.

METHODOLOGY

Periapical lesions were induced in Wistar rats by occlusal surface pulp exposure in mandibular first molars. The rats were randomly sacrificed 0, 7, 14, 21, 28, 35, 42 and 56 days after pulp exposure. The jaws that contained the first molars were obtained and routinely prepared for radiographic, histological, enzyme histochemical, immunohistochemical and double immunofluorescence analyses. Data were analysed by one-way analysis of variance and the Pearson correlation test.

RESULTS

The number of IL-23-positive cells increased from day 7 to day 35 and then gradually decreased. The number of osteoclasts increased and peaked on day 14 and then gradually decreased from day 21 to day 56. A significant positive correlation existed between the number of IL-23 positive cells and the size of bone resorption in periapical lesions from day 7 to day 56 (r = 0.875, P < 0.01).

CONCLUSIONS

Interleukin-23 can be observed and may be associated with inflammatory response and bone resorption in periapical lesions.

Effectiveness of the proton pump inhibitor omeprazole associated with calcium hydroxide as intracanal medication: an in vivo study

INTRODUCTION

The objective of this study was to evaluate the efficacy of the association of a proton pump inhibitor (omeprazole) with Ca(OH)(2) as intracanal medication in a rat model of periapical lesions.

METHODS

Periapical lesions were induced on the first right mandibular molar tooth of 36 male Wistar rats (6 per group). After 28 days, the distal canal of each tooth was prepared, filled with the respective dressing (negative control group, PEG 400; positive control group, Ca(OH)(2) + PEG400; test group, Ca(OH)(2) + omeprazole + PEG 400), and sealed with amalgam for 15 or 28 days. Microbiological samples were taken in 3 periods: S1, after 28 days of lesion induction; S2, after the biomechanical preparation; and S3, after the medication (15 and 28 days).

RESULTS

The radiographic and histologic analysis revealed that either Ca(OH)(2) or Ca(OH)(2) plus omeprazole dressings produced a reduction of periapical lesions at 28 days, when compared with the negative control group. The reduction of periapical lesions and inflammatory cell infiltration was visibly improved by associating omeprazole with Ca(OH)(2), with an increase of reparative bone areas. The microbiological assessment showed a significant decrease of colony-forming units count from S1 to S2 or S3 collecting times, but no differences were observed between the S2 and the S3 time-periods or among the experimental groups within the S3 period. Further bacterial characterization showed a possible selective activity of the medications.

CONCLUSIONS

Our data showed that association of omeprazole with Ca(OH)(2) favored a superior repair of rat periapical lesions and seemed to display different selective activity over endodontic microbiota, in comparison with the conventional Ca(OH)(2) dressing.

Radiographic assessment of photodynamic therapy as an adjunctive treatment on induced periodontitis in immunosuppressed rats

Objective

The aim of this study was to assess radiographically the effect of photodynamic therapy (PDT) as an adjunctive treatment to scaling and root planing (SRP) on induced periodontitis in dexamethasone-induced immunosuppressed rats.

Material and Methods

The animals were divided into 2 groups: ND group (n=60): saline treatment; D group (n=60): dexamethasone treatment. In both ND and D groups, periodontal disease was induced by the placement of a ligature in the left first mandibular molar. After 7 days, ligature was removed and all animals received SRP, being divided according to the following treatments: SRP: saline and PDT: phenothiazinium dye (TBO) plus laser irradiation. Ten animals per treatment were killed at 7, 15 and 30 days. The distance between the cementoenamel junction and the height of the alveolar bone crest in the mesial surface of the mandibular left first molars was determined in millimeters in each radiograph. The radiographic values were analyzed statistically by ANOVA and Tukey's test at a p value <0.05.

Results

Intragroup radiographic assessment (ND and D groups) showed that there was statistically significant less bone loss in the animals treated with PDT in all experimental periods compared to those submitted to SRP. Intergroup radiographic analysis (ND and D groups) demonstrated that there was greater bone loss in the ND group treated with SRP compared to the D group treated with PDT at 7 and 30 days.

Conclusion

PDT was an effective adjunctive treatment to SRP on induced periodontitis in dexamethasone-induced immunosuppressed rats.

Low-dose doxycycline inhibits bone resorption associated with apical periodontitis

AIM

To test the effect of low-dose doxycycline on bone resorption associated with apical periodontitis.

METHODOLOGY

Apical periodontitis was induced by occlusal pulp exposure in the mandibular first molars of 36 rats. Animals were divided into three groups of 12: group A received doxycycline in drinking water at a dose of 5.85 mg day(-1); group B received a dose of 1.48 mg day(-1) (one-quarter of the original dose); and group C received no medicament and served as the control. A bioassay determined the doxycycline serum levels. After 21 days, the mandibles were removed, radiographed and the radiographs scanned to generate digital images. These images were analysed morphometrically and the total area of the periapical bone resorption of the mesial and distal roots of each tooth was determined and used to compare the groups. Statistical analysis was completed using anova with repeated measures.

RESULTS

The mean doxycycline serum level in group A was 0.22(+/-0.03) microg mL(-1) and in group B below the detection level of the assay (<0.062 microg mL(-1)). The mean area of the periapical bone resorption in the control group C was 2.91(+/-0.61) mm(2). In animals treated with a low-dose doxycycline, the mean size of the bone resorption was significantly smaller at 1.59(+/-0.59) mm(2) (group A) and 1.72(+/-0.85) mm(2) (group B) (P = 0.001). No significant difference was found in the area of the bone resorption between these two groups A and B.

CONCLUSIONS

Low-dose doxycycline reduced the area of bone resorption associated with apical periodontitis in the mandibular first molar teeth of rats.

Effect of an estrogen-deficient state and alendronate therapy on bone loss resulting from experimental periapical lesions in rats

The aim of the research was to evaluate the impact of an estrogen-deficient state and alendronate (ALD) therapy on bone loss resulting from experimental periapical lesions in rats. Periapical lesions were induced on ovariectomized (OVX) and sham-ovariectomized (Sham) rats. After sample preparation, histologic and radiographic examination for periapical bone loss area and an enzyme histochemical test for tartrate-resistant acid phosphatase (TRAP) were performed. The results showed that OVX significantly increased bone loss resulting from periradicular lesions. After daily subcutaneous injection of ALD, the bone loss area and the number of TRAP-positive cells (osteoclasts) were reduced. These findings suggested that alendronate may protect against increased bone loss from experimental periapical lesions in estrogen-deficient rats. Given recent recognition of adverse effects of bisphosphonates, including an increased risk for osteonecrosis, the findings from this study should not be interpreted as a new indication for ALD treatment. However, they may offer insight into understanding and predicting outcomes in female postmenopausal patients already on ALD therapy for medical indications.

The effect of dexamethasone in the pathogenesis of ligature-induced periodontal disease in Wistar rats

The aim of this study was to evaluate, in rats, the role of the systemic use of dexamethasone in the pathogenesis of induced alveolar bone loss. In 26 female Wistar rats, ligatures were placed around the second upper molars, and the contralateral ones served as intra-group controls. Two groups were formed. The test group received 0.5 mg/kg of dexamethasone subcutaneously every third day during thirty days. The control group received the same amount of saline solution. After thirty days, the animals were sacrificed and their maxillae were removed. Sodium hypochlorite was used to prepare the specimens, and the cementum-enamel junction was stained with 1% methylene blue. Morphometric analysis of the alveolar bone loss was performed with standardized digital photographs, and the distance between the cementum-enamel junction and the alveolar bone crest was measured with the software ImageTool 3.0. Intra-examiner calibration revealed a Pearson correlation coefficient of 0.99. Statistical analysis was performed by paired or independent samplet tests, as appropriate (alpha = 0.05). Dexamethasone increased the mean alveolar bone loss in ligature-induced periodontitis in relation to the control group (0.77 and 0.61 buccally, and 0.65 and 0.56 palatally, respectively). No significant differences were observed intergroups in the teeth without ligatures. In the animal model used here, the use of dexamethasone increased the progression of ligature-induced alveolar bone loss.

C-Reactive Protein and Serum Amyloid A in a Canine Model of Chronic Apical Periodontitis

Increased levels of systemic inflammatory markers have been observed in patients with chronic dental diseases, such as marginal periodontitis. A canine model was used to determine if a systemic inflammatory response was evident during chronic apical periodontitis (CAP). Dental pulps in 10 dogs were exposed and infected with dental plaque to induce CAP. Blood samples were drawn preoperatively and postinfection when CAP was seen radiographically. In three of the 10 dogs, an intravenous challenge of Porphyromonas gingivalis A7436 was given subsequent to the development of CAP. An ELISA assay was used to measure the levels of C-reactive protein (CRP) and serum amyloid A (SAA) as markers of systemic inflammation. During CAP the levels of CRP and SAA were not statistically different from the preoperative values as determined by the Friedman test (p < 0.05). One dog, which had an unplanned trauma-induced laceration of the paw 2 days before blood sampling, showed a 40-fold increase in CRP. The 3 dogs challenged by intravenous P. gingivalis A7436 showed elevated levels of CRP, consistent with an acute phase response. These data demonstrate that the canine model provides a useful means for studying the systemic effects of apical periodontitis, and show that CAP is not associated with elevated CRP or SAA.

Pulp-dentine complex changes and root resorption during intrusive orthodontic tooth movement in patients prescribed nabumetone

Pulpitis, external root resorption, and pain may be experienced during orthodontic movement. The use of nonsteroidal anti-inflammatory drugs (NSAIDs) has been suggested to control these changes. The purpose of this study was to observe pulp-dentinal reactions, root resorption, tooth pain, and tooth movement after the application of a 4-ounce intrusive orthodontic force to human maxillary first premolars in patients given the NSAID nabumetone. Thirty-four maxillary first premolars were evaluated. A placebo was prescribed to 17 patients after an intrusive force was activated and reactivated for an 8-week period on the right side. The same procedure was repeated on the left side after patients were given nabumetone. Pulp-dentinal reactions and external root resorption were evaluated by histology. Pain and movement were also evaluated. Nabumetone was found to be useful in reducing pulpitis, external root resorption, and pain caused by intrusive orthodontic movement, without altering tooth movement in response to the application of orthodontic force.