Healing of Apical Periodontitis after Nonsurgical Treatment in Patients with Type 2 Diabetes

INTRODUCTION

The purpose of this prospective study was to compare the success of primary root canal treatment between type 2 diabetic and nondiabetic patients and to investigate the effect of periapical healing on glycated hemoglobin (HbA1c) in type 2 diabetic patients with apical periodontitis.

METHODS

Sixty mandibular molars with necrotic pulps and apical radiolucency (size ≥ 2 mm × 2 mm) were included in the study. Based on the HbA1c levels, patients were divided into 2 groups: type 2 diabetic (HbA1c ≥6.5%) and nondiabetic (HbA1c <6.5%). Forty-six teeth were evaluated at the 12-month follow-up time period. The primary outcome measure was the change in apical bone density as determined by the periapical index.

RESULTS

Both the diabetic and nondiabetic group depicted a significant reduction in the periapical score after endodontic treatment at the 12-month follow-up (P < .05). Significantly less periapical healing was observed in the diabetic group (43%) compared with the nondiabetic group (80%) at the 12-month follow-up (P < .05). HbA1c levels in the diabetic group increased at each follow-up after endodontic treatment.

CONCLUSIONS

Diabetes mellitus may have a negative impact on the outcome of endodontic treatment in terms of periapical healing. Nonsurgical endodontic treatment did not improve HbA1c levels in patients with type 2 diabetes.

Periapical microsurgery: the effect of root dentinal defects on short- and long-term outcome

INTRODUCTION

The purpose of this prospective clinical study was to evaluate the clinical outcome of endodontic microsurgery on roots exhibiting the presence or absence of dentinal defects at 1-year and 3-year follow-up period.

METHODS

One hundred fifty-five teeth were treated with periapical microsurgery using a modern microsurgical protocol in a private practice setting. The root apices were resected and inspected for dentinal defects with a surgical operating microscope and a 0.8-mm head diameter light-emitting diode microscope diagnostic probe light. After inspection, root-end preparations were performed using ultrasonic tips, and root-end fillings were placed. Follow-up visits occurred at 1 year and 3 years postoperatively. The primary outcome measure used was the change in the radiographic apical bone density, and the secondary outcome measure used was the absence of clinical symptoms.

RESULTS

Of the 155 treated teeth, a total of 134 teeth were assessed at the 1-year follow-up and 127 teeth at the 3-year evaluation. In the "intact" group, 94.8% healed at 1 year, and 97.3% healed at 3 years. In the "dentinal defect" group, 29.8% healed at 1 year, and 31.5% healed at 3 years. The baseline root condition of either "dentinal defect" or "intact" showed a statistical difference in the healing outcome at both 1 and 3 years.

CONCLUSIONS

This prospective periapical microsurgery study showed a significant superior clinical outcome for intact roots when compared with roots with dentinal defects at both 1 year and at 3 years postoperatively.

Analysis of multiple cytokine polymorphisms in individuals with untreated deep carious lesions reveals IL1B (rs1143643) as a susceptibility factor for periapical lesion development

INTRODUCTION

It has been proposed that individual genetic predisposition may contribute to persistent apical periodontitis. Cytokines are associated with levels of inflammation and are involved in caries, pulpal, and periapical tissue destruction. We hypothesized that polymorphisms in cytokine genes may contribute to an individual's increased susceptibility to apical tissue destruction in response to deep carious lesions.

METHODS

Subjects with deep carious lesions with or without periapical lesions (≥3 mm) were recruited at the University of Pittsburgh, Pittsburgh, PA, and the University of Texas at Houston, Houston, TX. Genomic DNA samples of 316 patients were sorted into 2 groups: 136 cases with deep carious lesions and periapical lesions (cases) and 180 cases with deep carious lesions but no periapical lesions (controls). Nine single-nucleotide polymorphisms in IL1B, IL6, TNF, RANK, RANKL, and OPG genes were selected for genotyping. Genotypes were generated by end point analysis using TaqMan chemistry (Invitrogen, Carlsbad, CA) in a real-time polymerase chain reaction instrument. Allele and genotype frequencies were compared among cases and controls using the PLINK program (http://pngu.mgh.harvard.edu/purcell/plink/). Ninety-three human periapical granulomas and 24 healthy periodontal ligament tissues collected postoperatively were used for messenger RNA expression analyses of IL1B.

RESULTS

A single-nucleotide polymorphism in IL1B (rs1143643) showed allelic (P = .02) and genotypic (P = .004) association with cases of deep caries and periapical lesions. We also observed altered transmission of IL1B marker haplotypes (P = .02) in these individuals. IL1B was highly expressed in granulomas (P < .001).

CONCLUSIONS

Variations in IL1B may be associated with periapical lesion formation in individuals with untreated deep carious lesions. Future studies could help predict host susceptibility to developing periapical lesions.

Pulpal and periradicular response to caries: current management and regenerative options

The pulp-dentin complex is a strategic and dynamic barrier to various insults that plague the dentition. Researchers have yet to understand the complete potential of this shifting junction and its components. The most common cause of injury to the pulp-dentin complex is carious breakdown of enamel and dentin. In recent years, there has been a change in restorative management of caries. The emphasis is on strategies to preserve dentin and protect the pulp. This article provides a brief review of the effect of caries on the pulp, of subsequent events on the periradicular tissues, and of current understanding of treatment modalities.

Masticatory tensile developed in upper anterior teeth with chronic apical periodontitis. A finite-element analysis study

Commonly is accepted that a non-vital tooth has a higher risk of root fracture but there is a relatively little knowledge about the specific biomechanical behavior of non-vital frontal teeth with chronic apical periodontitis. The aim of our study was to evaluate the deformation and tensile generated in these teeth while vertically loading them because it is crucial to assess the moment when the absorbed occlusal forces exceed the elasticity of root dentine. Using the method of finite-element analysis, we highlighted the distribution patterns of the compressive and tension tensile, as well as their concentration areas. The vertical forces of 100 N generate deformations of no clinical risk in teeth with chronic apical periodontitis. The tensile developed in these teeth are higher than those in the vital teeth are but do not exceed the value of the elastic modulus of the radicular dentin. By increasing the force to 300 N occur elastic deformations, which cannot be neglected anymore. Even so, the 300 N forces do not generate deformations of the alveolar bone. The highest tensile at loading with 300 N was generated in vertical direction but in the cervical area of the tooth also developed tensile in lingual and mesiodistal direction that must be taken into consideration because they are near the risk limit of the elasticity modulus. The crack lines or fractures can appear both in case of excessive or even usual but accumulative occlusal forces that gradually alter the mechanical resistance of the tooth.

Teaching dental pain with and without underlying oral physiology: learning implications

This study investigated whether teaching undergraduate dental students the diagnosis and management of acute dental pain alongside the underpinning oral physiology helped them to understand the topic better than teaching them acute dental pain as a separate entity. Each of three clinical years of dental students at the same dental school was taught in two groups. Each group was taught the signs/symptoms of five acute dental pain conditions by the same member of the staff. However, the teaching for one group of students in each year reminded the students about the physiology that underpinned the clinical symptoms. One week later, the students completed an open-ended questionnaire that required them to list signs/symptoms of the five dental pain conditions. For each year of dental students that was examined, the mean student marks were significantly higher (p<0.05) for those who were taught dental pain and the underlying physiology compared with students who were only taught dental pain as a stand-alone subject. This suggests that integrating biomedical science and clinical teaching is beneficial.

[The effect of age on the process of healing of chronic periapical inflammation]

INTRODUCTION

The aim of this study was to determine the effect of age on the process of healing of chronic periapical inflammation.

MATERIAL AND METHODS

The study was carried out in 59 patients with accidentally disclosed chronic periapical inflammation and no other pathology. The patients were allocated to two age groups: group I--from 17 to 44 years of age; group II--from 45 to 78 years of age. All teeth with periapical inflammation were endodontically treated. Control radiographs were taken 6 and 12 months later.

RESULTS

Radiographs taken after 6 months disclosed partial or complete restoration of periapical tissues in 79.5% of patients in group I and 65.0% of patients in group II. Radiographs after 12 months showed partial or complete healing in 94.8% of patients in group I and 90.0% of patients in group II.

CONCLUSIONS

The process of healing of chronic periapical inflammation lasted longer in patients aged 45-78 years than in patients aged 17-44 years. The outcome of treatment was similar in both groups.

Detection of Treponema denticola in root canal systems in primary and secondary endodontic infections. A correlation with clinical symptoms

AIM

The aim of the study was to investigate the presence of Treponema denticola in primary and secondary root-infected canal systems with periapical pathology and correlations with clinical signs and symptoms.

METHODOLOGY

Endodontic samples were obtained from canals of 102 teeth: 79 had primary endodontic disease and 23 secondary endodontic disease. For each tooth, clinical data including symptoms and X-ray appearance were examined. The presence of T. denticola biological samples from the root canal space was detected by a PCR assay.

RESULTS

T. denticola was detected in 24 out of the 79 teeth with primary infection and in 8 out of the 23 teeth with secondary infection. Teeth with specific clinical symptoms were frequently associated with T. denticola presence inside the root canal system.

CONCLUSIONS

The presence of T. denticola in root canal system in association with specific clinical signs and symptoms of endodontic disease strongly suggests that this spirochete might play a critical role in the pathogenesis of the acute infection and rapid bone tissue alterations in both primary and secondary endodontic infections.

The influence of chronic apical periodontitis on oral and general health

In healthy condition, the periodontal space between the root surface and the alveolar bone is relatively poor in cells. In case of root canal infection however, large number of immune-inflammatory cells infiltrate the periapical region of the affected teeth. A major issue is if and to what extent microbial and host cells contribute to lesion formation and whether the local inflammation may impair general health. The question is important as it may fundamentally influence the therapeutic strategy in patients with apical periodontitis. The aim of this paper is to review the results of recent experimental and clinical observations that investigate the importance of cellular interactions in exerting protective and destructive effects in periapical inflammatory lesions. The majority of studies indicate that the lesion would not develop in the absence of permanent release of bacteria and their by-products from the infected root canal. On the other hand, the formation of the classical granulation tissue is dependent on the presence and proper function of host cells and regulatory molecules. The dynamic encounter of root canal microbiota and the local immune system prevents overwhelming bacterial infiltration of the periradicular space but it is also connected with degenerative changes, most importantly bone resorption, resulting ultimately in tooth loss. However, by the use of proper endodontic methods, the lesion can be successfully treated in the majority of cases. Remineralization of the lost hard tissue will occur or the lesion will transform into an inert periapical scar.

Measurement of Mechanical Allodynia and Local Anesthetic Efficacy in Patients With Irreversible Pulpitis and Acute Periradicular Periodontitis

An essential feature of symptomatic periradicular inflammation is mechanical allodynia, defined as reduced mechanical pain thresholds. A previous study evaluating a new digital force transducer showed that it reliably measures mechanical pain thresholds of teeth with normal periradicular tissues. In this study, we tested the hypothesis that the force transducer quantitatively measures mechanical allodynia in teeth with acute periradicular periodontitis (APP) and detects the effects of local anesthetic injection. Mechanical pain thresholds were measured in patients (n = 30) with irreversible pulpitis (IP) and APP and compared with their contralateral teeth. The results show that the mechanical pain thresholds of teeth with IP and APP were reduced by 77% compared with contralateral control teeth. The administration of local anesthesia reversed the mechanical allodynia by 62%, and significant sex-specific effects were observed. In addition, the normal teeth contralateral to the symptomatic teeth had lower mechanical thresholds than those observed in healthy volunteers, suggesting that central sensitization occurs during this type of odontalgia. Thus, we show that the mechanical pain thresholds are significantly reduced in teeth with IP and APP and that the force transducer has potential application as a diagnostic aid in measuring mechanical allodynia and as an outcome measure in endodontic clinical trials such as pharmacologic studies and mechanistic research.

Pulp Revascularization of Immature Dog Teeth With Apical Periodontitis

This study examined the ability of a collagen solution to aid revascularization of necrotic-infected root canals in immature dog teeth. Sixty immature teeth from 6 dogs were infected, disinfected, and randomized into experimental groups: 1: no further treatment; 2: blood in canal; 3: collagen solution in canal, 4: collagen solution + blood, and 5: negative controls (left for natural development). Uncorrected chi-square analysis of radiographic results showed no statistical differences (p >or= 0.05) between experimental groups regarding healing of radiolucencies but a borderline statistical difference (p = 0.058) for group 1 versus group 4 for radicular thickening. Group 2 showed significantly more apical closure than group 1 (p = 0.03) and a borderline statistical difference (p = 0.051) for group 3 versus group 1. Uncorrected chi-square analysis revealed that there were no statistical differences between experimental groups for histological results. However, some roots in each of groups 1 to 4 (previously infected) showed positive histologic outcomes (thickened walls in 43.9%, apical closure in 54.9%, and new luminal tissue in 29.3%). Revascularization of disinfected immature dog root canal systems is possible.

Kinetic Study of Immunohistochemical Colocalization of Antigen-presenting Cells and Nerve Fibers in Rat Periapical Lesions

Immune and nervous systems play key roles in periapical pathosis; however, their spatial associations, which may be a prerequisite for paracrine interactions in the progression of periapical lesions, remain to be examined. In this study we examined the distribution and frequency of spatial associations between major histocompatibility complex class II molecule-expressing antigen-presenting cells (APCs) and protein gene product 9.5-immunoreactive nerve fibers in experimentally induced rat periapical lesions using double-immunofluorescence staining and confocal laser scanning microscopy. When active lesion expansion started, macrophage-like APCs frequently associated with nerve fibers around the apex. When the lesions were starting to stabilize, however, close associations between APCs with dendritic morphology and nerve fibers were found mostly in the periphery of lesions. CD86+ mature dendritic cells were also observed in this area. These findings suggest that functional interactions between APCs and nerve fibers may play some roles in the development of self-defense reactions in periapical lesions.

Immature teeth with periradicular periodontitis or abscess undergoing apexogenesis: a paradigm shift

Four clinical cases of immature teeth that developed periradicular periodontitis or abscess underwent a conservative treatment approach, i.e. without canal instrumentation. Instead, only copious 2.5% NaOCl irrigation was performed. All cases presented herein developed mature apices after 7 months to 5 years after the initial treatment without complications, although narrowing canal space was observed. Our clinical observations support a shifting paradigm toward a conservative approach by providing a favorable environment for tissue regeneration. The mechanism of this continued development and formation of the root end is discussed.

Influence of residual bacteria on periapical tissue healing after chemomechanical treatment and root filling of experimentally infected monkey teeth

The purpose of this study was twofold: first, to determine the influence on the healing of the periapical tissues when selected bacterial strains and combinations thereof remain after root canal treatment; and, second, the relationship to healing of the quality of the root filling. In eight monkeys, 175 root canals, previously infected with combinations of four or five bacterial strains and with radiographically verified apical periodontitis, were endodontically treated, bacteriologically controlled, and permanently obturated. After 2-2.5 yr, the periapical regions were radiographically and histologically examined. Of these teeth, 48 root canals were also examined for bacteria remaining after removal of the root fillings. When bacteria remained after the endodontic treatment, 79% of the root canals showed non-healed periapical lesions, compared with 28% where no bacteria were found. Combinations of residual bacterial species were more frequently related to non-healed lesions than were single strains. When no bacteria remained, healing occurred independently of the quality of the root filling. In contrast, when bacteria remained, there was a greater correlation with non-healing in poor-quality root fillings than in technically well-performed fillings. In root canals where bacteria were found after removal of the root filling, 97% had not healed, compared with 18% for those root canals with no bacteria detected. The present study demonstrates the importance of obtaining a bacteria-free root canal system before permanent root filling in order to achieve optimal healing conditions for the periapical tissues.

Influence of Orthodontic Dental Movement on the Healing Process of Teeth With Periapical Lesions

The purpose of this study was to histomorphologically evaluate (in dog's teeth) the influence of tooth movement in the healing of chronic periapical lesions. Thirty roots of incisors and premolars of two dogs (1-year-old) were used in this research. After pulpectomy, the root canals remained exposed to the oral environment for 6 months for achievement of periapical lesions. Twenty root canals were biomechanically prepared and received a calcium hydroxide dressing for 14 days before being filled with gutta-percha points and Sealapex sealer. After root canal treatment, some incisors were submitted to orthodontic movement, whereas the other roots remained without orthodontic movement. The orthodontic appliance was removed at 5 months and 15 days after treatment, the dogs were killed 15 days later and the specimens were prepared for histomorphological analysis. The results showed that the orthodontic movement delayed, but did not hinder, the periapical healing process.

[Magnetic laser therapy in the treatment of apical periodontitis]

A new method for the treatment of apical periodontitis, making use of Optodan laser, differs from the known method by more rapid periapical tissue regeneration, which is paralleled by high antiinflammatory effect of magnetic laser therapy at early stages of treatment.

IL-1 alpha and TNF-alpha expression in rat periapical lesions and dental pulp after unilateral sympathectomy

OBJECTIVES

Apical periodontitis is an inflammatory disease characterized by bone resorption, and sympathetic nerves are known to modulate bone resorption and bone remodeling. Higher numbers of osteoclasts and larger periapical lesions have been observed after sympathectomy in rats, but the mechanisms underlying the inhibitory effect of sympathetic nerves on osteoclasts are unknown. This study aimed to test the hypothesis that sympathetic nerves inhibit the production of the bone-resorbing pro-inflammatory cytokines IL-1 alpha and TNF-alpha in rat periapical lesions.

METHODS

Rats were unilaterally sympathectomized and apical lesions were induced by exposing the dental pulp of molar teeth to the oral microflora. We quantified the cytokines IL-1 alpha and TNF-alpha by enzyme-linked immunosorbent assay, and immunohistochemical analysis was done for qualitative localization. Pulp from intact incisor teeth was tested as a control.

RESULTS

We showed that IL-1 alpha was increased, but not TNF-alpha, in the periapical lesions on the sympathectomized side. Both IL-1 alpha and TNF-alpha were expressed in unexposed pulp. TNF-alpha was significantly decreased in the denervated incisor pulp, whereas the level of IL-1 alpha remained unchanged.

CONCLUSIONS

This study suggests that sympathetic nerves have an inhibitory effect on IL-1 alpha in periapical lesions and a stimulatory effect on TNF-alpha in the intact rat pulp.

The periapical space--a dynamic interface

The ultimate aim of endodontic treatment is to encourage the healing of apical periodontitis, or to prevent it from occurring if it was not present prior to treatment. Apical periodontitis is a general term used to describe an inflammatory response to irritation caused by the contents of a root canal system and it has several distinct forms. The most common is a granuloma but this can develop into other disease entities such as an abscess, a periapical pocket cyst or a true cyst, all of which present as radiolucencies. However, periapical radiolucencies may also be caused by extra-radicular infections, foreign body reactions and periapical scars, or they may be due to other tumours and cysts that have not originated from pulp disease. Practitioners must recognise and understand the different pathological entities and the dynamic interactions that occur in the periapical tissues in order to correctly diagnose and treat these conditions.

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.

[The healing dynamics of periapical destructive lesions in x-ray imaging]

Regeneration processes in periapical tissues were followed up after bone defect repair with hydroxyapatite-based osteoplastic preparations. The terms of regeneration depended on the size of bone defect. The data were evaluated by densitometry.

Apparent periapical repair without operative intervention: a case report and discussion

CASE REPORT

A case is described where substantial reduction of an established periapical lesion appeared to take place in the absence of operative intervention, and as the crown of the tooth was progressively destroyed by dental caries. The case raises debate on the pathogenesis, diagnosis and monitoring of endodontic lesions, and may stimulate renewed research interest in these most fundamental elements of clinical endodontology.

Apexification of an infected untreated immature tooth

A case of a traumatized permanent young tooth in which apexification occurred without the benefit of endodontic treatment is reported. It illustrates how a immature incisor that underwent pulp necrosis and periapical inflammation could progress to complete apical formation.

Cholesterol as an aetiological agent in endodontic failures--a review

Presence of cholesterol clefts in apical periodontitis lesions is a common histopathological observation. However, a potential aetiological association of cholesterol crystals to non-resolving apical periodontitis lesions after endodontic treatment has been suggested only recently. This article is an attempt to explain the biological basis for the inability of body cells to eliminate the local accumulation of cholesterol crystals, and to consolidate available clinical and experimental data in support of the view that massive accumulation of cholesterol crystals in inflamed periapical tissues can interfere with the periapical healing after conventional root canal treatment. As the irritating cholesterol crystals and certain other aetiological agents of failed endodontic treatment exist outside the root canal system, it is concluded that re-treatment alone, of such cases, is unlikely to resolve the factors that sustain the lesion. Apical surgery is indicated for successful management of such cases.

Pathophysiology of acquired dental diseases of the horse

Periodontitis, infundibular necrosis, and periapical infection are dental diseases commonly affecting adult horses. Routine dental examinations and care may help to prevent these diseases. Further investigation of the treatment of horses with these diseases using local antimicrobial therapy, restorative dentistry, and endodontic therapy is needed. An understanding of the pathogenesis of these diseases aids in diagnosis and treatment. Gingival hyperplasia and odontogenic tumors are uncommon but should remain in a list of differential diagnoses when examining a horse with pertinent clinical signs. Recognition of odontogenic tumors as early as possible may facilitate surgery. Examination of the oral cavity of foals beyond the neonatal period should allow identification of brachygnathia and timely treatment when indicated.

Immediate implants placed into infected sites: a histomorphometric study in dogs

The study the effect of chronically infected sites on the immediate placement of implants, periapical lesions were induced in the third and fourth premolars of four dogs and the contralateral teeth were used as controls. Nine months after the induction of periapical lesions, experimental and control teeth were extracted, and 28 IMZ implants were immediately placed. After a healing period of 12 weeks, the animals were sacrificed, the hemimandibles were removed, and specimens were prepared to be hard-sectioned and stained with toluidine blue. All areas healed without inflammation or exudation and all implants were clinically immobile and were radiographically determined to be surrounded by normal-appearing bone. Histologically, there were no signs of infection, and the histomorphometric analyses revealed that 28.6% and 38.7% had osseointegrated for the experimental and control implants, respectively. The difference was not statistically significant. It was concluded that chronically infected sites, such as those showing signs of periapical pathosis, may not be a contraindication for immediate implants, if certain clinical measures and preoperative and postoperative care are taken.

Immunohistochemical examination of the distribution of macrophages and CGRP-immunoreactive nerve fibers in induced rat periapical lesions

To clarify the role of calcitonin gene-related peptide (CGRP) in the development of periapical lesions, we examined the distribution of CGRP-immunoreactive (IR) nerve fibers and macrophages, and the behavior of bone tissues in experimentally induced rat periapical lesions by immunohistochemical and quantitative methods. Although no extensive changes were observed at 7 days after pulp exposure, CGRP-IR nerve fibers increased in number until 28 days with a decrease thereafter. These neural changes were closely correlated with the alteration in number of macrophages except on day 7 when macrophages were significantly increased in number as compared with control rats. Tissue repair began to take place and a decrease in number of osteoclasts was observed when the density of CGRP-IR nerve fibers reached a peak. These results suggested that there might be a close relationship between macrophages and CGRP-IR nerve fibers and that CGRP-IR nerve fibers might participate in tissue repair in experimentally induced rat periapical lesions.

Time-course and risk analyses of the development and healing of chronic apical periodontitis in man

Roots with and without preoperative chronic apical periodontitis were root canal treated and followed clinically and radiographically yearly for up to 4 years. Of 732 roots treated, 599 (82%) were available for evaluation at one or several recalls. Chronic apical periodontitis (CAP) was recorded with the periapical index scoring system. CAP developed in 29 of 473 (6%) of teeth without preoperative signs of disease, whereas 111 of 126 (88%) initially diseased roots showed signs of healing. The rate of healing CAP and the rate of emerging CAP were calculated, and analyses of event occurrence each year of observation were performed. Peak incidence of healing or emerging CAP was at 1 year in both instances. Risk assessments at 2, 3, and 4 years did not indicate an added risk of filled roots developing CAP during this period. Complete healing of preoperative CAP in some instances required 4 years for completion, while signs of initiated, but incomplete, healing were visible in at least 89% of all healing roots after 1 year. Risk analyses may provide relevant information in addition to or in substitution for success/failure analyses.

Periapical neural changes after pulpectomy

Pulpectomy and pulpal necrosis result in severance of the nerves that supply the pulp as well as loss of their target organ. Inflammatory changes commonly extend into the periapical region to involve those nerves. The neural response to pulpal loss combined with periapical inflammation is a derangement of the periodontal plexus normally located in the center of the periodontal space around the apical third of the root; the result is the formation of a disorganized group of sprouting and branching axons that have some features in common with neuromas. The inflammatory and neural responses continue for at least a year even when pulpectomy is followed by canal debridement and obturation. Then the responses are reduced but not eliminated by steroids. Root canal therapy with techniques that do not leave residual inflammation still results in increased periapical innervation; the increase seems to be an organized addition to the normal periradicular plexus.

Histopathological observations of periapical repair in teeth with radiolucent areas submitted to two different methods of root canal treatment

Dogs' teeth with induced chronic periapical periodontitis were treated endodontically by two different methods, and the results were compared. A total of 40 root canals from the upper and lower premolars of two dogs were prepared chemomechanically. In method 1, a high-concentration (5.25%) hypochlorite solution was used during the instrumentation of the root canal, and an antibacterial dressing was applied between sessions, followed by filling of the root canal. In method 2, a low-concentration (0.5%) sodium hypochlorite solution was used as an adjunct to mechanical debridement, and the root canal was filled during the same session. The histopathological results showed that method 1 led to better periapical repair than method 2.

Periodontal healing in teeth with periapical lesions. A clinical retrospective study

The purpose of the present investigation was to compare clinical periodontal healing in periodontally involved teeth with and without pulpal pathosis. The investigation was conducted as a retrospective study on a consecutive referral population. The periapical conditions in endodontically involved single-rooted teeth from a selected patient sample were evaluated and correlated with their periodontal healing pattern. Multiple regression analysis of the registered variables showed that initial mean pocket depth and time elapsed after treatment significantly influenced change in pocket-depth. Non-surgical treatment of periodontal pockets exceeding 2.5 mm in teeth with horizontal marginal defects, over the observation period, showed significantly reduced mean pocket depth reduction in teeth with periapical pathology compared to teeth without periapical pathology. It was, furthermore, evident that proximal restorations, abutments for fixed bridges and root fillings with and without dowels did not significantly influence pocket depth reduction in the present material. It was concluded, based on the present results, that a root-canal infection, evident as a periapical radiolucency, if left untreated may in the long term perspective result in retarded or impaired periodontal healing following periodontal therapy and, consequently, should be given appropriate consideration when coordinating endodontic therapy and periodontal treatment.

[Periodontal function and oral hygiene following an operation for apicoectomy]

The author analyzes the effect of the dental root apex resection on the function of marginal periodontal tissues of the operated on tooth and oral hygiene of 103 patients with chronic periapical foci of odontogenic infection, aged 12 to 53, on the basis of the data of monitoring the changes in the content of gingival fluid, depth of the gingival grooves or pouches, and the Schiller-Pisarev test and hygiene index. The operation in question was found to essentially disorder the biologic equilibrium in the marginal periodontal tissues and to deteriorate the hygienic status of the oral cavity. The developing shifts are reversible and disappear in two weeks after surgery. The author emphasizes that such patients should be timely trained to take care of the oral cavity in order to improve its hygienic status in the postoperative period.

The relationship between clinical symptoms and anaerobic bacteria from infected root canals

The purpose of this study was to investigate the correlation between the composition of bacterial flora from infected root canals and clinical symptoms. The materials evaluated consisted of 28 teeth from 25 patients with apical periodontitis. Eubacterium were found to be significantly related to acute or chronic clinical symptoms and Peptococcus, Peptostreptococcus, and Porphyromonas gingivalis to subacute clinical symptoms. We suggested that Peptococcus, Peptostreptococcus, Eubacterium, Porphyromonas, and Bacteroides were significantly related to percussion pain; Porphyromonas and Bacteroides were significantly related to odor in the infected root canals. Many Bacteroides were isolated from most of the infected root canals.

[Endo-periodontal relations. Microbiological and clinical aspects]

Periodontics and endodontics share common objectives and common field of interest. Both disciplines treat lesions of the periodontal tissues; in their marginal aspect the first, in the periapical aspect the latter. These relationships have not been well understood for a long time. This article is a review of the literature on the topic aimed at clarifying the anatomic, microbiological, pathogenetic relationship in the periodontal and endodontic lesions.

A histochemical study of bone remodeling during experimental apical periodontitis in rats

An apical periodontitis experimental model was produced by means of opening the pulp chamber of the mandibular first molar in Wistar strain rats. In particular, the behavior of bone tissue in the vicinity of the root apex was investigated histochemically, ultrastructurally, and quantitatively. In addition, in order to demonstrate the effects of prostaglandin on the formation process of apical periodontitis, we examined the effects of indomethacin on bone remodeling during experimental apical periodontitis. These experiments suggested that prostaglandin may stimulate osteoclastic bone resorption and that the relationship between bone resorption and formation in apical periodontitis is a coupling phenomenon.

Perspectives, controversies and directives on pulpal-periodontal relationships

While established clinical, radiographic and histologic criteria exist to explain the intimate relationship of the pulp and periodontium during pathological states, the recognition, diagnosis and treatment of this perplexing interplay remains a challenge for the practitioner. This dynamic interrelationship is investigated with a focus on simplicity and succinctness to enhance diagnostic probabilities, clarify treatment modalities and provide realistic prognoses in management.

Continuing root formation following apexification treatment

A case report is presented in which continuing root formation occurred in an immature mandibular second premolar after calcium hydroxide apexification treatment. An apical hard tissue barrier was accompanied by a separate disto-apically growing root 18 months posttreatment. Histologic evaluation of the root revealed immature hard tissue mixed with calcium hydroxide, connective tissue and bone, apically in the original root canal. In the separate new formed part of the root, pulp tissue, odontoblasts, predentin, cementum and an apical foreman could be identified.

[Pathogenesis of periapical inflammatory processes]

The Authors, after a short description of the anatomy of the root canal, deal with the aetiological factors of the periapical pathology, acute and chronic. They examine the pathogenetic mechanisms of acute flogistic process of the periapical tissue and consider the principal mediators involved in the tissue lesion.

[Effect on the development of permanent successors due to the extraction and non-extraction of infected deciduous teeth]

The purpose of this study was to clarify the effects on the eruption and root formation of the permanent successors of deciduous teeth affected by periapical periodontitis. Materials used were forty-one healthy infant dogs about two months old. Standardized X-ray films were taken every two weeks. The period of study ran from the age of ten weeks to twenty eight weeks until the roots of the permanent successors were completed. A total of 328 mandibular teeth were used and classified as P2 and P3 with their preceding deciduous teeth being Dp2 and Dp3. The following four groups were used in this experiment. 1) Extraction group with infected deciduous teeth: The infected deciduous teeth were extracted after being left for four weeks following pulpectomy. 2) Extraction group with healthy deciduous teeth: Healthy deciduous teeth were extracted from fourteen-week olds. 3) Left-alone group with infected deciduous teeth: After pulpectomy the infected deciduous teeth were left until they were shed naturally. 4) Healthy group (control): Untreated teeth were observed which represented the opposites of all the teeth examined in the previous three groups. A study was made of the changes in location, eruption and root formation of the permanent successors of deciduous teeth in affected with periapical periodontitis and the condition of eruption and root formation of the permanent successors. The result were as follows. 1. Appearance rate of periapical periodontitis: 1) DP2: Two weeks after pulpectomy, periapical periodontitis was observed in eleven out of twenty-one teeth (52.4%), and after four weeks in seventeen out of twenty-one teeth (81.0%). 2) Dp3: Two weeks after pulpectomy, periapical periodontitis was observed in eighteen out of twenty-one teeth (85.7%), and after four weeks in all of the experimental teeth. The appearance rate of periapical periodontitis in Dp3 was higher than in Dp2. 2. Eruption of permanent successors: 1) Extraction group with infected deciduous teeth: (1) The eruption of permanent successors was accelerated more than the other experimental groups. This tendency was stronger in P3 than in P2. (2) There were changes in location in the upper and lower directions of P2 before extraction of Dp2, in the lower direction for P3 before extraction of Dp3, and in the upper direction for P2 and P3 after extraction of Dp2 and Dp3. 2) Extraction group with healthy deciduous teeth: (1) Eruption of P2 appeared to be almost the same as the control group, but the eruption of P3 was delayed slightly at the eruption from the alveolar bone.(ABSTRACT TRUNCATED AT 400 WORDS)

Image analysis of endodontic radiographs: digital subtraction and quantitative densitometry

In this study computerized image analysis procedures were applied to endodontic radiographs. Kontron IBAS 2000 is a commercially available image analysis system with processing routines applicable to radiograph digitizing and transformations. The system was evaluated for: its ability to harmonize blackening and contrast in endodontic radiographs; its ability to compensate for angulation distortion of sequential exposures of individual teeth; its potential for application of digital subtraction methods; and its use in automated gray-level analyses of diseased and healthy bone areas in endodontic radiographs. The Kontron IBAS 2000 system proved suitable for all applications. However, the specificity of the subtraction procedure was limited by some inherent problems in the harmonization of blackening and in the subtraction process itself. On the other hand, automated gray level measurements proved to be a robust method for unbiased and quantitative assessment of healing of apical periodontitis.

[Morphological features of regional lymph nodes and coagulation of the draining lymph in case of experimental apical periodontitis]

During the early stages of experimental apical periodontitis the vascular permeability of the postcapillary venule is increasing. In the lymph draining from the submandibular lymph node it develops a syndrome of disseminated intravascular coagulation. In the sinus of the lymph nodes are stated fibrin sedimentation and thrombus formation. These processes are caused by a correlation of lymph and blood clotting factors and are not existing in the later inflammatory processes.

Apical closure in the presence of pulpal necrosis: report of two cases

This article reports apical closure in two cases in which necrotic pulps were present and no endodontic treatment was performed prior to closure. Possible mechanisms for the occurrence are suggested.

Influence of the enlargement of the apical foramen in periapical repair of contaminated teeth of dog

Root canals of dogs' premolar teeth were exposed to contamination and to the development of periapical inflammation over a period of 45 days. Root canals were overinstrumented 2 mm beyond the apical foramen with file No. 60 and were underfilled by 2 to 3 mm short of the roentgenographic apex. Ninety days after endodontic treatment, healing and ingrowth of connective tissue into the root canal occurred in 67.8% of the cases. These results suggest that the diameter of the apical foramen and the intensity of the canal contamination are determining factors for periapical tissue repair in cases of pulpal necrosis.