Incidence of periradicular pathoses in endodontic treatment failures

Association between Clinical/Radiographic Characteristics and Histopathological Diagnoses of Periapical Granuloma and Cyst

OBJECTIVE

 The aim of this study was to determine the association between clinical/radiographic characteristics and histopathological diagnoses of periapical granuloma and cyst obtained from the teeth treated with endodontic microsurgery.

MATERIALS AND METHODS

 The clinical, radiographic (periapical and cone-beam computed tomography), and histopathological data were collected from patients' dental records of endodontic microsurgery on the teeth with periapical lesions. These lesions were histopathologically diagnosed as either granuloma or cyst, at the Endodontic Clinic, Faculty of Dentistry, Mahidol University, Bangkok, Thailand, from 2016 to 2021 according to inclusion and exclusion criteria. The data were analyzed using bivariate analysis and a multinomial logistic regression at a significance level of p-value less than 0.05.

RESULTS

 A total of 83 patients (58 females and 25 males) with an average age of 45 to 49.5 years old met the criteria including 68 periapical granulomas (81.9%) and 15 periapical cysts (18.1%). A periapical lesion involving multiple teeth in a periapical radiograph was significantly associated with the histopathological diagnosis of periapical cyst (p < 0.05). Such periapical lesion was six times more likely to be periapical cyst than periapical granuloma.

CONCLUSIONS

 A significant factor for predicting periapical cyst from periapical granuloma was the presence of a periapical lesion with multiple-teeth involvement in a dental radiograph.

Prevalence of Nonendodontic Diagnoses in Periapical Biopsies: A 6-year Institutional Experience

INTRODUCTION

The purpose of this study was to identify non-endodontic periapical lesions (NPLs) mimicking endodontic pathosis most frequently encountered by clinicians.

METHODS

A retrospective study was conducted on biopsies obtained from 2015-2020 at Texas A&M College of Dentistry oral pathology laboratory. The online database was screened for cases submitted as suspected endodontic pathology using specific keywords. Histological diagnoses were collected to determine prevalence of NPLs that were originally thought to be of endodontic origin. The frequency and percentage of endodontic pathology and NPLs were documented.

RESULTS

Among 6,704 biopsies clinically diagnosed as endodontic lesions, 190 (2.8%) were histopathologically diagnosed as NPLs. The most frequent NPLs were odontogenic keratocyst (n=70, 36.8%), cemento-osseous dysplasia (n=27; 14.2%), and dentigerous cyst (n=22; 11.6%). Of all NPLs, 3.7% were malignant neoplasms, with the most common diagnosis being squamous cell carcinoma. Of 6,514 endodontic histological diagnoses, the prevalence of periapical granulomas and cysts was 60.2% (n=3,924) and 39.1% (n=2,549), respectively.

CONCLUSIONS

While most endodontic submissions are likely to be histologically diagnosed as periapical granuloma or cyst, the clinician should be aware that a small portion of these lesions may be non-endodontic in origin and possibly neoplastic in nature. Histopathological evaluation of biopsied specimens is critical to achieve a proper diagnosis to ensure appropriate management of patients.

Evaluation of ultrasonography as a diagnostic tool in the management of periapical cysts and granulomas: A clinical study

Purpose

The aim of this study was, firstly, to determine the concordance of ultrasonographic and histopathological diagnoses in patients in whom apical resection was already indicated. Secondly, this study aimed to determine whether lesions were periapical granulomas or cysts, and to compare them after root canal treatment using ultrasonography and periapical radiographs.

Materials and Methods

In the first stage of the study, ultrasonographic and histopathologic diagnoses of 10 lesions were compared. Secondly, the periapical radiographs and ultrasonographic images of 44 lesions were measured. The presence of internal vascularity was determined by ultrasonographic color and power Doppler modes. Follow-up examinations of healing after root canal treatment were performed using ultrasonography and periapical radiographs, and these modalities were compared.

Results

In the periapical granuloma and cyst groups, the measurement values decreased for all variables. There was no significant difference in the dimensional changes of lesions between the 2 groups, and ultrasonography and periapical radiographs were compatible. The pre-diagnoses were compared with histopathological diagnoses and were found to be compatible.

Conclusion

The ultrasonographic color and power Doppler techniques could be an effective method for diagnosing periapical lesions as cysts or granulomas. After root canal treatment of granulomas and cysts, the dimensional shrinkage and healing patterns appear to be similar. Ultrasonography and periapical radiographs were consistent in terms of dimensional comparisons, and ultrasonography may be an alternative method for follow-up of the healing of periapical lesions.

Nonendodontic periapical lesions: a retrospective descriptive study in a Brazilian population

Background

Several nonendodontic diseases can occur in the periapical region, resembling endodontic inflammatory conditions. Therefore, the aim of the present study was to determine the frequency of nonendodontic periapical lesions diagnosed in a Brazilian population.

Material and Methods

The files of two Oral Pathology laboratories were reviewed and all cases including at least one clinical diagnosis of endodontic periapical lesions were selected for the study. After initial selection, demographic and clinical data, clinical diagnosis and final diagnosis were reviewed and tabulated. Final diagnosis included endodontic periapical lesions, and benign and malignant nonendodontic periapical lesions. Data were descriptively and comparatively analyzed among the three groups, with a significance level of 5% (p<0.05).

Results

Nonendodontic periapical lesions were identified in 208 (19%) out of the 1.125 registries included in the final sample. Benign nonendodontic periapical lesions (200 cases, 18%) were mostly odontogenic keratocysts, ameloblastomas, nasopalatine cysts, dentigerous cysts, glandular odontogenic cysts, and benign fibroosseous lesions. Malignant nonendodontic periapical lesions (8 cases, 1%) included carcinomas, adenocarcinomas, and melanoma. In general, nonendodontic periapical lesions were more common in males and in the posterior mandible (p>0.05).

Conclusions

The frequency of nonendodontic periapical lesions was high and, although the general distribution was similar to the results from other populations, some features were probably associated with the profile of the studied populations and to the methods applied in the present study. Knowledge on differential diagnosis of endodontic and nonendodontic periapical lesions is essential to avoid unnecessary treatments and diagnostic delay in routine dental practice.

Key words:Differential diagnosis, nonendodontic, periapical lesion, pulp necrosis.

Non-endodontic periapical lesions clinically diagnosed as endodontic periapical lesions: A retrospective study over 15 years

Background

This study aimed to provide the frequency and demographic data of non-endodontic periapical lesions clinically misdiagnosed as endodontic periapical lesions from a Southeast Asian population over a 15-year period.

Material and Methods

A retrospective study was conducted from departmental archives between 2005 and 2019. Cases clinically diagnosed as endodontic periapical lesions were retrieved. Then, cases with a histopathological diagnosis of non-endodontic periapical lesion were selected. Demographic data of non-endodontic periapical lesions were recorded. Radiographic features of cases with available radiographs were analyzed.

Results

Of 1,566 cases clinically diagnosed as endodontic periapical lesion, 157 cases received a histopathological diagnosis of non-endodontic origin. Eighteen different histopathological diagnoses were identified. The most frequent lesion was dentigerous cyst (n= 51, 32.48%) followed by odontogenic keratocyst (n=31, 19.75%), nasopalatine duct cyst (n=18, 11.46%) and ameloblastoma (n=15, 9.56%). Three cases of malignant tumors, including adenoid cystic carcinoma, mucoepidermoid carcinoma, and metastatic papillary thyroid carcinoma were observed.

Conclusions

Non-endodontic periapical lesions constituted 10.03% of cases clinically diagnosed as endodontic periapical lesions. Histopathological examinations of non-endodontic periapical lesions revealed a variety of lesions ranging from foreign body reaction, cysts, fibro-osseous lesions, benign tumors and primary or metastatic malignant tumors. Of clinical significance is that some non-endodontic periapical lesions had different treatment modalities and prognoses compared with endodontic lesions. Therefore, dentists must be aware that periapical radiolucent lesions are not always a consequence of pulpal necrosis.

Key words:Ameloblastoma, dentigerous cyst, endodontic periapical lesions, non-endodontic periapical lesions, odontogenic keratocyst.

A Retrospective Brazilian Multicenter Study of Biopsies at the Periapical Area: Identification of Cases of Nonendodontic Periapical Lesions

INTRODUCTION

The purpose of this study was to analyze the features of lesions obtained from biopsies at the periapical area of teeth with a radiographic or clinical initial diagnosis of apical periodontitis.

METHODS

A retrospective study was conducted on biopsies obtained from 1953-2018 at 3 Brazilian oral and maxillofacial pathology centers. Cases of endodontic and nonendodontic periapical lesions (NPLs) with a clinical diagnosis of endodontic pathoses were retrieved. Data regarding patient age, sex, and anatomic location were obtained from patients' records. The frequency and percentage of cases with clinical diagnoses of a periapical cyst, periapical granuloma, or dentoalveolar abscess were recorded, and the final histopathologic diagnosis was documented.

RESULTS

Among 66,179 oral biopsies, 7246 (10.94%) were clinically diagnosed as periapical disease, 306 (4.22%) of which were histopathologically diagnosed as NPLs. The most frequent NPLs were odontogenic keratocysts (n = 107, 34.96%) followed by dentigerous cysts (n = 48, 15.68%). The mean age at diagnosis was 39.68 years with a range of 6-80 years. A total of 159 (51.96%) cases occurred in females and 147 (48.03%) in males (female to male ratio = 1.08:1). Most lesions (137, 44.77%) were located in the posterior mandible.

CONCLUSIONS

A wide variety of histopathologic diagnoses, including benign odontogenic and nonodontogenic cystic and tumorous lesions, infectious diseases, and malignant neoplasms, was reported in the present survey. The features presented in this study were consistent with previous findings reported in the literature.

Disturbed bone remodelling activity varies in different stages of experimental, gradually progressive apical periodontitis in rats

Bone remodelling keeps going through the lifespan of human by bone formation and bone resorption. In the craniofacial region, mandibles act as the main force for biting and chewing, and also become susceptible to a common bone-loss disease, namely, apical periodontitis, once infected dental pulp is not treated timely, during which bone resorption occurs from the apical foramen to the apical bone area. Although conventional root canal treatment (RCT) can remove the most of the infection, chronical apical periodontitis due to incomplete removal of dental pulp and subsequent microleakage will become refractory and more challenging, and this process has scarcely been specifically studied as a bone remodelling issue in rat models. Therefore, to study chronical and refractory apical periodontitis owing to incomplete cleaning of infected dental pulp and microleackage in vivo, we establish a modified rat model of gradually progressive apical periodontitis by sealing residual necrotic dental pulp and introducing limited saliva, which simulates gradually progressive apical periodontitis, as observed in the clinical treatment of chronical and refractory apical periodontitis. We show that bone-loss is inevitable and progressive in this case of apical periodontitis, which confirms again that complete and sound root canal treatment is crucial to halt the progression of chronical and refractory apical periodontitis and promote bone formation. Interestingly, bone remodelling was enhanced at the initial stage of apical periodontitis in this model while reduced with a high osteoblast number afterwards, as shown by the time course study of the modified model. Suggesting that the pathological apical microenvironment reserve its hard tissue formation ability to some degree but in a disturbed manner. Hopefully, our findings can provide insights for future bone regenerative treatment for apical periodontitis-associated bone loss.

Tratamento cirúrgico e conservador de cisto periapical de grande proporção: relato de caso

O objetivo deste estudo foi descrever uma técnica de tratamento conservadora, cuja conduta preconizada foi a realização da descompressão seguida pela enucleação cística através do relato de um caso de cisto periapical de grande extensão. Paciente de 50 anos de idade, melanoderma, apresentando cisto periapical com aproximadamente 4,5 cm em seu maior diâmetro associado ao incisivo central inferior esquerdo. Na primeira etapa do tratamento foi realizada descompressão cística e biopsia incisional, cujo exame histopatológico confirmou o diagnóstico clínico. Após 25 semanas de acompanhamento, houve uma considerável regressão do tamanho da lesão e a mesma foi enucleada sem comprometimento dos elementos dentários envolvidos e dos tecidos adjacentes. O relato de caso evidenciou que o tratamento cirúrgico e conservador pode ser um recurso em cistos periapicais de maior dimensão, sendo importante a cooperação do paciente no acompanhamento pós-operatório.

Clinical and radiological analysis of a series of periapical cysts and periapical granulomas diagnosed in a Brazilian population

BACKGROUND

Periapical cysts (PC) and periapical granulomas (PG) are the two most common chronic inflammatory periapical diseases, but their clinicoradiological characteristics can vary depending on the methods employed in each study. The aim of the present work was to analyze the clinical and radiological profile of a series of PC and PG diagnosed in a Brazilian population.

MATERIAL AND METHODS

The files of two Oral Pathology laboratories were reviewed and all cases diagnosed as PG and PC were selected for the study. Clinical and radiological information were retrieved and data were tabulated and descriptively and comparatively analyzed.

RESULTS

Final sample was composed by 647 inflammatory periapical lesions, including 244 PG (38%) and 403 PC (62%). The number of women affected by PG was significantly higher than the number of women affected by PC (p=0.037). Anterior region of the maxilla was the most common affected area for both entities (39% of the cases), but the most common anatomical location of PG (anterior maxilla and posterior maxilla) was different from PC (anterior maxilla and posterior mandible) (p<0.0001). Upper lateral incisor was the most affected tooth. The mean radiological size of the PC was larger than the mean radiological size of the PG (p<0.0001) and PC showed well-defined radiological images more frequently than PG (p<0.0001).

CONCLUSIONS

PC were more common than PG, both showed predilection for adult females, most lesions affected predominantly the anterior maxilla and PC presented larger mean radiological diameter and well-defined images when compared with PG. Key words:Periapical granuloma, periapical cyst, radicular cyst, diagnosis, Oral Pathology.

Retrospective analysis of nonendodontic periapical lesions misdiagnosed as endodontic apical periodontitis lesions in a population of Taiwanese patients

OBJECTIVE

We aimed to evaluate nonendodontic periapical lesions clinically misdiagnosed as endodontic periapical pathoses in a population of Taiwanese patients.

MATERIALS AND METHODS

Cases (2000-2014) of histopathological diagnoses of nonendodontic periapical lesions were retrieved from all cases with a clinical diagnosis of radicular cyst, apical granuloma, or apical periodontitis in the institution. These cases were regarded as misdiagnosed nonendodontic periapical lesions, of which the types and frequencies, in addition to the demographic data, were determined.

RESULTS

Four thousand and four specimens were clinically diagnosed as endodontically associated pathoses, of which 118 cases (2.95%) received a histopathological diagnosis of a nonendodontic pathologic entity, the most frequent lesion being keratocystic odontogenic tumor (KCOT, n = 38, 32.20%), followed by fibro-osseous lesion (n = 18, 15.25%), and dentigerous cyst (n = 13, 11.02%). Nine malignant lesions in the periapical area [squamous cell carcinoma (n = 7, 5.93%), adenoid cystic carcinoma (n = 1, 0.85%), and Langerhans cell histiocytosis (n = 1, 0.85%)] were also noted.

CONCLUSIONS

A wide variety of histopathological diagnoses, including benign odontogenic and non-odontogenic cystic and tumorous lesions and infectious diseases, as well as malignant lesions, was noted in these 118 cases of nonendodontic periapical lesions. Squamous cell carcinoma was the most predominant malignancy of nonendodontic periapical lesions misdiagnosed as apical periodontitis lesions from imaging examination overlooking the clinical findings.

CLINICAL RELEVANCE

The current data form a useful basis for clinicopathological investigation and educational teaching regarding nonendodontic periapical lesions misdiagnosed as endodontic apical periodontitis lesions.

Surgical Endodontics in Dogs: A Review

Surgical endodontic therapy (apical surgery) is a treatment alternative aimed at removing periapical inflammatory tissue followed by apical resection and retro-filling of the root canal. These procedures are performed through a trans-osseous approach. Terminology pertinent to this article include: apical (periapical) curettage – a surgical procedure to remove diseased tissue from the alveolar bone in the apical region of a pulpless tooth; apical cyst – a cyst in bone at the apex of a pulpless tooth. It is believed that such cysts arise after the death of the pulp from noxious physical, chemical, or bacterial stimulation of epithelial rests of Malassez; apicoectomy (apical resection) – amputation of the apical portion of the root and removal of soft tissue in the bone; epithelial rests of Malassez – cords, strands, or clusters of ectodermal cells in the periodontal ligament (or sometimes alveolar bone) derived from remnants of Hertwig's epithelial root sheath. These cells frequently begin proliferating when inflammation occurs in the periodontal ligament and are believed to be responsible for the genesis of the epithelial lining of apical cysts.

Radiographic and histological evaluation of persistent periapical lesions associated with endodontic failures after apical microsurgery

AIM

To determine the histology of persistent periapical lesions associated with nonsurgical endodontic treatment failures and to compare radiographically the sizes of periapical lesions and the presence or absence of the radiopaque lamina with the histological findings.

METHODOLOGY

Ninety-three anterior teeth designated for apical microsurgery were included in the study. After taking standard radiographs of all cases using the parallel technique, the films were scanned and evaluated for the size of periapical radiolucent lesions and the presence or absence of radiopaque lamina by two calibrated observers. Biopsy specimens were obtained during apical microsurgery and examined under light microscopy by oral pathologists. Histological analysis established diagnoses of granuloma, cyst, abscess and scar tissue. Interobserver agreement was evaluated by the kappa test, and the relationship between histological diagnosis and lesion size was analysed by the Pearson's chi-square test.

RESULTS

The 93 specimens consisted of 72% periradicular granulomas; 21.5% radicular cysts, including two keratocysts; 4.3% abscesses; and 2.2% scar tissue. Cystic prevalence increased as the size of the periapical lesion increased; however, there was no correlation between the presence of a radiopaque lamina and histological diagnosis of cyst.

CONCLUSIONS

Neither radiographic size nor presence of an associated radiopaque line alone was sufficient to determine the type of lesion. Histological examination is required in order to reach to a definitive diagnosis.

Comparative evaluation of immunohistochemistry, histopathology and conventional radiography in differentiating periapical lesions

Background and Aim:

Periapical lesions often present differently on the radiograph resulting in a dilemma in the mind of the dentist to arrive at a final diagnosis. Although, histopathologic diagnosis has been used for confirmation of the true nature of periapical lesion, the concept of transformation of periapical granulomas containing epithelium without cystification into cyst remains controversial. The aim of this in vivo study was to evaluate the efficacy of conventional radiography and histopathology in differentiating periapical lesions in adjunct with immunohistochemical analysis.

Aim:

Periapical lesions often present differently on the radiograph resulting in a dilemma in the mind of the dentist to arrive at a final diagnosis. Although, histopathologic diagnosis has been used for confirmation of the true nature of periapical lesion, the concept of transformation of periapical granulomas containing epithelium without cystification into cyst remains controversial. The aim of this in vivo study was to evaluate the efficacy of conventional radiography and histopathology in differentiating periapical lesions in adjunct with immunohistochemical analysis.

Materials and Method:

Thirty patients having large periapical radiolucency that do not heal successfully with routine endodontic therapy in relation to either maxillary or mandibular anterior teeth were selected for the study. Intraoral periapical radiographs were obtained and provisional diagnosis of the apical areas were made. Endodontic surgery was performed to enable histopathogical investigation. The histopathological interpretation was done to arrive at a final diagnosis and selected questionable granulomas were subjected for cytokeratin (CK-14) stain.

Results:

The histopathological profile of lesions consisted of 66.66% periapical granulomas, 10% cysts, 6.67% abscess and 16.67% granulomas with cystic potential. The radiographic and histopathologic correlation was found in only 30% of these cases. Strong CK-14 expression was observed in all five cases of periapical granuloma with cystic potential.

Conclusion:

The radiographic diagnosis of periapical lesions remains inconclusive. Although histopathologic examination of periapical lesions gives true nature, the precise nature of subsets of periapical granulomas may be achieved with adjunct use of immunohistochemical markers.

Periapical lesions are not always a sequelae of pulpal necrosis: a retrospective study of 1521 biopsies

AIM

To record the incidence of lesions that were not the sequelae of pulpal necrosis (non-SPN) amongst 1521 biopsies of periapical lesions submitted with a clinical diagnosis of a sequelae of pulpal necrosis (SPN).

METHODOLOGY

A retrospective study of 1521 biopsy request forms of specimens submitted for histopathological examination with a clinical diagnosis 'periapical inflammation', 'periapical abscess', 'periapical granuloma' or 'periapical cyst' during an arbitrarily selected 14-year period was undertaken. Gender and age of the patient, site and maximum diameter of the lesion, symptoms, inclusion of the final diagnosis in the differential diagnosis and specialty of the clinician submitting the biopsy material were recorded in each case. The final diagnosis for each case was extracted from the pathology report, and two groups were formed, SPN and non-SPN lesions. Differences between the respective features of SPN and non-SPN cases were analysed with Yate's chi-square test and t-test (significance level P < 0.05) RESULTS: In 52 of the 1521 cases examined (3.42%), the histological diagnosis was not consistent with a SPN. In most non-SPN cases, the histopathological diagnosis was not included in the differential diagnosis. The keratocystic odontogenic tumour [odontogenic keratocyst (OKC)] was the most frequent non-SPN lesion (34.62%). Other, yet less frequent, non-SPN lesions included glandular odontogenic cysts, lateral periodontal cysts, central ossifying fibromas as well as malignancies (metastatic carcinomas and Langerhans cell histiocytosis).

CONCLUSIONS

Non-SPN lesions appeared in the periapical region mimicking a SPN, although rarely. Most of them were developmental cysts, in particular OKCs, but odontogenic tumours, such as ameloblastoma, or malignant lesions were also diagnosed. Histological examination of tissue harvested from periapical lesions should be performed, in particular when those lesions are large.

Relação entre presença de fendas de cristais de colesterol em lesão periapical e nível de colesterol sérico

INTRODUÇÃO: Uma infecção crônica nos tecidos periapicais pode desencadear uma lesão periapical em função da estimulação e da proliferação dos restos epiteliais de Malassez. Ao estudo microscópico, é possível detectar a presença de fendas de cristais de colesterol no interior de cistos e granulomas. De acordo com alguns estudos, a origem do colesterol no interior de lesões no periápice pode ser, parcialmente, por causa da condensação e da cristalização de colesterol dentro da parede do cisto. Outros estudos afirmam que a presença de colesterol pode ser derivada de produtos metabólicos locais ou da circulação vascular. OBJETIVO: O presente estudo teve por objetivo analisar a relação entre as fendas de cristais de colesterol encontradas nas lesões periapicais e os níveis de colesterol sérico. MATERIAL E MÉTODO: Estudo observacional de natureza descritiva, que incluiu 70 pacientes portadores de lesões periapicais, de acordo com exame radiográfico, atendidos no Departamento de Odontologia da Universidade Federal de Sergipe. Esses pacientes foram submetidos à exodontia da unidade dentária acometida e à remoção da lesão periapical, sendo esta peça encaminhada para exame anatomopatológico. Na mesma consulta, era solicitado um lipidograma para avaliação das taxas de colesterol sérico dos pacientes. RESULTADO: Fendas de cristais de colesterol estavam presentes apenas em cistos grandes (maiores que 1,5 cm de diâmetro, aproximadamente) e, portanto, mais antigos. CONCLUSÃO: A presença de cristais de colesterol é rara nas lesões periapicais. O estudo sugere uma relação entre a presença dos cristais de colesterol e o índice de colesterol sérico elevado, em lesões grandes e antigas.

Radiological diagnosis of periapical bone tissue lesions in endodontics: a systematic review

This systematic review evaluates the diagnostic accuracy of radiographic methods employed to indicate presence/absence and changes over time of periapical bone lesions. Also investigated were the leads radiographic images may give about the nature of the process and the condition of the pulp in nonendodontically treated teeth. Electronic literature search included the databases PubMed, Embase and CENTRAL from January 1950 to June 2011. All languages were accepted provided there was an abstract in English. The MeSH terms were 'Cone beam computed tomography (CBCT)', 'Radiography, panoramic', 'Periapical diseases', 'Dental pulp diseases', 'Sensitivity and specificity', 'receiver operating characteristics (ROC) curve', 'Cadaver', 'Endodontics' and 'Radiography dental'. Two reviewers independently assessed abstracts and full text articles. An article was read in full text if at least one of the two reviewers considered an abstract to be potentially relevant. Altogether, 181 articles were read in full text. The GRADE approach was used to assess the quality of evidence of each radiographic method based on studies of high or moderate quality. Twenty-six studies fulfilled criteria set for inclusion. None was of high quality; 11 were of moderate quality. There is insufficient evidence that the digital intraoral radiographic technique is diagnostically as accurate as the conventional film technique. The same applies to CBCT. No conclusions can be drawn regarding the accuracy of radiological examination in identifying various forms of periapical bone tissue changes or about the pulpal condition.

Retrograde peri-implantitis

Retrograde peri-implantitis constitutes an important cause for implant failure. Retrograde peri-implantitis may sometimes prove difficult to identify and hence institution of early treatment may not be possible. This paper presents a report of four cases of (the implant placed developing to) retrograde peri-implantitis. Three of these implants were successfully restored to their fully functional state while one was lost due to extensive damage. The paper highlights the importance of recognizing the etiopathogenic mechanisms, preoperative assessment, and a strong postoperative maintenance protocol to avoid retrograde peri-implant inflammation.

Epidemiologic evaluation of the outcomes of orthograde endodontic retreatment

INTRODUCTION

Teeth undergoing initial endodontic therapy have a very high survival rate. Some teeth that continue to show signs of pathosis after the initial therapy will require nonsurgical (orthograde) retreatment. Outcome assessment of endodontic retreatment is crucial for appropriate case selection and treatment planning. However, reports on outcomes of orthograde endodontic retreatment performed by endodontists are limited in number, and the reported data vary. In this study, outcomes of orthograde endodontic retreatment performed on 4744 teeth were assessed during a period of 5 years.

METHODS

Data were obtained from retreatments that were performed by endodontists participating in the Delta Dental Insurance plan that insures approximately 15 million individuals in the USA.

RESULTS

Overall, 89% of teeth were retained in the oral cavity 5 years after the endodontic retreatment. Four percent of all teeth underwent apical surgery that occurred mostly within 2 years from completion of orthograde retreatment. Eleven percent of teeth were extracted at the end of the 5-year observation period.

CONCLUSIONS

It appears that orthograde endodontic retreatment yields high incidence of tooth retention after 5 years.

A Twenty-year Survey of Pathologic Reports of Two Common Types of Chronic Periapical Lesions in Shiraz Dental School

Background and aims

Accurate differential diagnosis between radicular cysts and periapical granulomas cannot be made from radiographs alone. Histological prevalence studies, therefore, assume special importance and may aid the clinician in making judgments regarding therapy. The incidence of radicular cysts has ranged with wide discrepancies in data. The purpose of this study was to evaluate recorded pathologic reports of two common types of chronic periapical lesion in Shiraz Dental School.

Materials and methods

In this study, biopsy reports of 227 specimens of chronic periapical lesions were reviewed. The following information was extracted from each report: patient’s gender, age, tooth associated with the lesion and the pathological diagnosis. Probable significant differences in the occurrence of lesions between different ages and genders were analyzed using chi-square test.

Results

15.9% of the lesions were granulomas, and 84.1% were cysts. A slight difference in the occurrence of the lesions was found between males and females with no statistical significance (P > 0.005). The highest incidence of both lesions was in the third decade of life. No significant differences were found in age distribution of the lesions. The most common location for two lesions was the maxillary anterior teeth.

Conclusion

Histological differentiation between cysts and granulomas is not always accurate and serial sectioning of excisional biopsies is more valuable than randomized sectioning of curetted biopsies.

Relative frequency of teeth needing conventional and surgical endodontic treatment in patients treated at a graduate endodontic clinic--a Penn Endo database study

OBJECTIVE

The objective of this study was to identify the most commonly retreated tooth at a postgraduate endodontics program and to compare this result with teeth requiring primary root canal treatment as well as those that required further surgical endodontic treatment.

STUDY DESIGN

The study population consisted of 6,894 patients treated between 2000 and 2005 by endodontic postgraduate students at the University of Pennsylvania School of Dental Medicine. Data regarding tooth type and endodontic treatment rendered were obtained from the Penn Endo database.

RESULTS

Initial root canal treatment was most commonly done on mandibular molars. Anterior teeth were 1.411 times more likely to undergo NSRT than molars. Maxillary molars were 1.048 times more likely to undergo conventional retreatment than mandibular molars. Maxillary anterior teeth were 3.032 times more likely than mandibular molars to undergo surgical treatment.

CONCLUSIONS

Mandibular molars may most commonly receive initial root canal treatment but it is the anterior teeth that are more likely to undergo surgical and nonsurgical retreatment. Maxillary molars are more likely to receive surgical intervention than mandibular molars. These data call for further investigation into the reasons for such discrepancy.

On the causes of persistent apical periodontitis: a review

Apical periodontitis is a chronic inflammatory disorder of periradicular tissues caused by aetiological agents of endodontic origin. Persistent apical periodontitis occurs when root canal treatment of apical periodontitis has not adequately eliminated intraradicular infection. Problems that lead to persistent apical periodontitis include: inadequate aseptic control, poor access cavity design, missed canals, inadequate instrumentation, debridement and leaking temporary or permanent restorations. Even when the most stringent procedures are followed, apical periodontitis may still persist as asymptomatic radiolucencies, because of the complexity of the root canal system formed by the main and accessory canals, their ramifications and anastomoses where residual infection can persist. Further, there are extraradicular factors -- located within the inflamed periapical tissue -- that can interfere with post-treatment healing of apical periodontitis. The causes of apical periodontitis persisting after root canal treatment have not been well characterized. During the 1990s, a series of investigations have shown that there are six biological factors that lead to asymptomatic radiolucencies persisting after root canal treatment. These are: (i) intraradicular infection persisting in the complex apical root canal system; (ii) extraradicular infection, generally in the form of periapical actinomycosis; (iii) extruded root canal filling or other exogenous materials that cause a foreign body reaction; (iv) accumulation of endogenous cholesterol crystals that irritate periapical tissues; (v) true cystic lesions, and (vi) scar tissue healing of the lesion. This article provides a comprehensive overview of the causative factors of non-resolving periapical lesions that are seen as asymptomatic radiolucencies post-treatment.

Endodontic Treatment Outcome: Survey of Oral Health Care Professionals

This study assessed the opinion of oral health care professionals regarding the predictability of initial endodontic treatment, expected long-term outcome and the importance of placing a coronal coverage after completion of treatment. An eight-item questionnaire was distributed among oral health care professionals. There were 49% of participants who responded that the expected retention rate of teeth 5 to 10 yr after endodontic treatment was more than 90%, whereas 44% responded that such retention rate was between 70 to 80%. The majority of the participants also responded that the need for additional treatment, such as retreatment, apical surgery or extraction, was expected to occur within the first 3 yr after endodontic treatment if initial treatment has failed. About 87% of participants responded that placing coronal coverage after completion of endodontic treatment in premolars and molars was very important for long-term tooth retention and 92% responded that overall, endodontic treatment was a predictable procedure with long-term tooth retention rate. Statistically significant associations were found between years of experience and expected rate of retention for both the total group of respondents (p < 0.001) and for general practitioners when examined separately (p < 0.002). Statistically significant associations were only found for general practitioners between years of experience and their responses regarding the need for additional treatment (p < 0.05) and overall predictability of endodontic treatment (p < 0.02). A trend was found between the professionals' years of experience and their opinion regarding the importance of coronal coverage. Of the group who had more than 20 yr of experience, about 87% considered coronal coverage to be very important for long-term tooth retention. In conclusion, it appears that most clinicians participating in this study consider endodontic therapy to be a predictable procedure with long-term tooth retention rate. Their opinions also reflect the variations that currently exist in the literature regarding the reported outcome of endodontic treatment.

Periapical cyst repair after nonsurgical endodontic therapy--case report

This article presents the procedures that must be considered for periapical cyst repair after nonsurgical endodontic treatment. The case of a periapical cyst associated to the left maxillary lateral incisor is reported. Nonsurgical root canal therapy was performed and lesion healing was confirmed radiographically after 24 months. Differential diagnosis, endodontic infection control, apical foramen enlargement and filling of the cystic cavity with a calcium hydroxide paste were important procedures for case resolution.

Endodontic Treatment Outcomes in a Large Patient Population in the USA: An Epidemiological Study

Outcome assessment of endodontic treatment is critical for appropriate case selection and treatment planning. However, reports on outcomes of nonsurgical endodontic treatment vary considerably. Epidemiological studies done in a large patient population and over a long follow-up period can provide the clinician with useful tools for clinical decision-making and assessment of tooth prognosis. In this study, outcomes of initial endodontic treatment done in 1,462,936 teeth of 1,126,288 patients from 50 states across the USA was assessed over a period of 8 yr. Treatment was done by private general practitioners and endodontists participating in the Delta Dental Insurance plan that insures approximately 14 million individuals in the USA. Overall, 97% of teeth were retained in the oral cavity 8 yr after initial nonsurgical endodontic treatment. The combined incidence of untoward events such as retreatments, apical surgeries, and extractions was 3% and occurred mostly within 3 yr from completion of treatment. Analysis of the extracted teeth revealed that 85% had no full coronal coverage. A significant difference was found between covered and noncovered teeth for all tooth groups tested (p < 0.001). In conclusion, it appears that initial nonsurgical endodontic treatment is a predictable procedure with high incidence of tooth retention after 8 yr.

Internal apical resorption and its correlation with the type of apical lesion

AIM

To determine the presence of various periapical pathologies and their association with the presence and extent of internal apical inflammatory root resorption in human teeth.

METHODOLOGY

A total of 75 root apices from extracted teeth with periapical lesions were examined. Semi-serial sections of soft tissue lesions were stained with HE. The lesions were classified as non-cystic or cystic, and according to the degree of abscess severity: 0, 1, 2 or 3. The apices were reduced to 3 mm in length and longitudinally cut so that the internal aspect could be analyzed under scanning electron microscopy (SEM). Internal root resorption was also classified as 0, 1, 2 or 3 according to the extent of the resorbed area. Additionally, six vital teeth were used as a control.

RESULTS

Non-cystic lesions with severe abscesses were the most common finding (70.7%), while 20% of the lesions were cystic (4% little or no abscess; 16% severe abscesses). Non-cystic lesions with little or no abscess comprised 9.3% of the sample. Of the root canals containing periapical lesions, 48% had internal apical resorption in more than half of the area, while 25.3% of the sample had no internal resorption. Resorption degree 1 was identified in 12% of the cases, and 14.7% showed resorption degree 2. The control group displayed significantly less internal resorption than the test groups.

CONCLUSIONS

Most periapical lesions (86.7%), whether cystic (16.0%) or non-cystic (70.7%), showed large collections of acute inflammatory cells. Apical internal resorption was present in 74.7% of roots and was associated with periapical lesions. There was no correlation between internal apical resorption and the histological diagnosis of the lesions.

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

AIM

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

METHODOLOGY

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

RESULTS

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

CONCLUSIONS

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

Identification of GM3 as a marker of therapy-resistant periradicular lesions

The purpose of this study was to analyze the profile of glycosphingolipids (GSLs) in periradicular lesions refractory to endodontic treatment. Sixteen periapical lesions were removed surgically from patients (experimental group) and compared with 10 samples of periodontal ligament removed from extracted intact third molars (control group). After the GSLs extraction and purification procedures were performed the neutral and acidic GSL fractions were analyzed by high-performance thin-layer chromatography and quantified by densitometry. Data reported herein show that: (i) tissues in the experimental group presented about twice as much GSLs as the control group; (ii) lesion tissues express lactoneotetraosylceramide, and lactofucopentaosyl (IV) ceramide, whereas these neutral GSLs are absent in normal tissues; and (iii) normal tissues express GT1b, whereas lesions cells do not express this ganglioside. In contrast lesion tissues express GM3, which is conspicuously absent in normal tissues.

Comparison of clinical and histologic diagnoses in periapical lesions

OBJECTIVE

To determine the frequency with which histopathologic examination of periapical biopsy specimens contributed information not anticipated clinically.

STUDY DESIGN

Clinical and histopathologic information from 805 sequentially submitted periapical biopsy specimens over a 2-year period was compared. Clinical data included endodontic status, age and sex of patient, location of lesion, and submitting clinician. Histopathologic diagnoses were categorized as 1) sequelae of pulpal necrosis (SPN), 2) complicated SPN (CSPN) with infection or antral involvement, or 3) periapical lesions unrelated to pulpal necrosis (PLUPN).

RESULTS

Of the 805 cases, 788 (97.9%) were SPN, 9 (1.1%) were CSPN, and 8 (1%) were PLUPN, representing a range of locally aggressive but benign lesions and 1 malignancy. Comparison of clinical and histologic diagnoses indicated that the clinical interpretation was inaccurate in 4.1% of cases (suggesting SPN in PLUPN cases or PLUPN in SPN cases). In another 0.9% of cases, the histologic analysis (indicating CSPN) contributed additional information to the clinical diagnosis.

CONCLUSIONS

A histopathologic examination contributed clinically relevant information in 5.0% of submitted cases. General extrapolation of this figure is not possible. Theoretical considerations, which could positively or negatively bias this figure, are discussed.

Periradicular curettage

Periradicular curettage is a part of the treatment procedure of periradicular surgery. Its main purpose is to remove pathological periradicular tissues for visibility and accessibility to facilitate the treatment of the apical root canal system, or sometimes for the removal of harmful foreign materials present in the periradicular area. Inflammatory periradicular lesions (granuloma and cysts) are the responses of the periradicular tissues to irritants from the root canal and not from the periradicular area unless medicaments and/or filling materials have been forced through the apical foramina or perforations into the periodontium. Histologically, the inflammatory periradicular lesion is similar to healing granulation tissue, which is composed of cells which have natural and specific immunological defence capability and cooperate by means of cytokines to amplify the protective mechanisms of the host. Accordingly, it is not necessary to completely curette out all the inflamed periradicular tissues during surgery, since this granulation-like tissue will be incorporated into the new granulation tissue as part of the healing process. To control the source of irritants in the root canal is far more important than to remove all periradicular tissues affected by the irritants. The successful removal of all irritants from the root canal system results in resolution of pulpally induced periradicular lesions. In the case where the periradicular lesion is caused by endodontic instruments or cytotoxic filling materials placed in the periradicular tissues, removal of these foreign objects is required for resolution of the lesion.

Types and incidence of human periapical lesions obtained with extracted teeth

OBJECTIVES

To determine (1) the frequency of the incidence of abscess, granuloma, and radicular cyst among human periapical lesions obtained with extracted teeth; and (2) whether periapical cysts occur in two categories when histologically analyzed in relation to the root canals.

STUDY DESIGN

A total of 256 lesions were analyzed. The specimens were decalcified and embedded in plastic. Serial sections or step-serial sections were prepared, and the sections were evaluated on the basis of predefined histopathologic criteria.

RESULTS

The 256 specimens consisted of 35% periapical abscess, 50% granuloma, and 15% cysts. The latter occurred in two categories, the apical true cysts and the apical pocket cysts.

CONCLUSIONS

These results show (1) the low incidence of radicular cysts among periapical lesions as against the widely held view that almost half of all periapical lesions are cysts; and (2) the occurrence of two classes of radicular cysts. We are of opinion that the pocket cysts may heal after root canal therapy but the true cysts are less likely to be resolved by conventional root canal treatment.

Importance of anatomic variables in endodontic treatment outcomes: case report

Surgical endodontic treatment was performed after a large periradicular lesion failed to resolve following nonsurgical intervention. The subsequent periradicular surgery resulted in healing with scar formation. Assessment of the resected root apex revealed a complex anatomy. The ramifications of these anatomical findings and the periradicular tissue response in healing are discussed relative to prognosis and ultimate treatment outcomes.