PERIAPICAL PATHOLOGY: COMPARISON OF CLINICAL DIAGNOSIS AND HISTOPATHOLOGICAL FINDINGS

Abstract

Background

Periapical lesions are often diagnosed on clinical and radiological basis that may be different from the histological finding. The purpose of this study was to compare clinical and radiographic features with histological diagnosis of periapical pathology.

Methodology:

A 22 year retrospective analysis of records of teeth diagnosed with periapical lesions that had periradicular surgery and the specimen sent for histopathological examination. Cases with incomplete records were excluded. Age, gender, site of lesion, clinical diagnosis, radiographic report and histopathological diagnosis etc were extracted from the records. The data were analyzed using SPSS version 20.0. Chi square test was used to test association between clinical and histological diagnosis at 95% level of confidence (i.e. p=0.05).

Results:

Nineteen cases were analyzed in patients within age range of 17 to 57years with a mean age of 32.2±11.7 years and male to female ratio of 1.1:1. All the affected teeth were upper incisors. Majority (n= 13; 68.4%) of the cases were clinically diagnosed to be periapical cyst. While on histological analysis, majority (n=16; 84.2%) of the total cases were diagnosed as periapical granuloma. Ten cases (76.9%) out of 13 diagnosed clinically to be periapical cyst had sclerotic border (p=0.003).

Conclusion:

This study showed sensitivity and specificity of radiographs in detecting periapical lesions were reduced when compared with histology. The insufficiency of conventional radiography in diagnosing periapical lesions could lead to unnecessary surgery for the patient, thus the need for advanced imaging to provide improved quality of diagnosis, treatment planning and prognosis.

Introduction

In the early signs of periapical disease and remnants of disease, certain morphological features in bone are difficult to distinguish1 and endodontists, like other clinicians, are repeatedly faced with such problems. Traditionally, periapical radiographs have been used clinically to diagnose periapical pathology2. Larger radiolucency along with perpendicular insertion can lead to a diagnosis of a cyst while an oblique insertion may indicate a diagnosis of periapical granuloma; however, these methods are not conclusive3. Attempts to diagnose these lesions pre-operatively, with periapical radiographs, contrast media, Papanicolou smears, and albumin tests4have proven to be inaccurate.

Other factors that may hinder the clinical and radiographic diagnosis of these osteolytic lesions include the structural and evolutionary variations of a periapical granuloma and the radiographic features observed in radicular cysts that are often undefined3. Also, associated periradicular lesions cannot always be truly assessed with conventional radiographs 5,6 and the roots area may be difficult to assess due to the fact that they are two dimensional, but the diagnostic information in this missing ‘third dimension’ is of particular relevance in surgical planning7,8. Thus, clinical diagnosis which is often based on radiographic presentation of periapical lesions could be different from the histological diagnosis9^-11.

Consequently, a histological study of the biopsied periapical lesion can be used to evaluate the clinical symptoms and the radiographic findings against the type of periradicular pathology and confirm the diagnosis12. The purpose of the study was thus to compare the clinical/radiographic diagnosis of periapical pathology with the histopathological diagnosis and to evaluate the accuracy of clinical/radiographic diagnosis of periapical cyst.

Patients & Methods

This was a retrospective analysis of records of teeth diagnosed with periapical lesion in the Conservation clinic of Restorative Department of University College Hospital Ibadan over a 22 year period (January 1990 to December 2012). Cases of periapical lesion that had periradicular surgery done and had the periapical biopsied specimen sent for histopathology from this clinic were recorded and analyzed.

Data were extracted from patients’ case notes, the clinical day book and the histopathological records. Demographic and clinical data such as age, gender, site of lesion, tooth or teeth involved, clinical diagnoses, radiographic report and histopathological diagnoses were extracted from the records.

Inclusion criteria included cases that had adequate clinical and radiographic findings documented and also had histopathology report documented. The clinical/radiographic diagnoses were recorded as verified by Consultant Endodontists in Conservation Clinic while the histopathology results were verified by Oral Pathologists. Cases with incomplete records were excluded.

The clinical diagnoses recorded include chronic periapical abscess, chronic apical periodontitis, apical periodontitis, perioendo lesion, infected periapical cyst, periapical cyst, and radicular cyst. Radiographic reports included well circumscribed radiolucency with sclerotic border and diffuse radioluscency with ill defined border, while histology reports recorded include periapical granuloma, and periapical cyst. The periapical lesions were then further radiographically classified into two groups: periapical granuloma and periapical cysts, with cases of well defined/circumscribed radioluscency with sclerotic border on radiograph classified as periapical cyst13while other cases were classified as periapical granuloma.

Cases were then analysed according to age, gender, site of the lesions, clinical diagnoses and histopathological diagnoses. The data were presented using summary statistics and analysed with the SPSS version 20.0. Chi square test was used to test association between clinical and histological diagnosis at 95% level of confidence (i.e. P=0.05).

The ability of clinical/radiographic assessment to diagnose periapical cyst or granuloma correctly (sensitivity) and the ability to detect the absence of these pathologies (specificity) were calculated using true-positives (TPs), false-positives, true-negatives (TNs), and false-negatives in clinical diagnoses and histopathologic findings. Other diagnostic accuracy tests; positive predictive value (PPV), negative predictive value (NPV), of clinical/radiographic diagnosis of periapical lesions (granuloma versus periapical cyst) were calculated using histopathologic findings as gold standard.

Results

Twenty- five cases with periapical pathology that had periradicular surgery done and the biopsied tissue sent for histopathology were identified from the records of the conservation clinic over the study period. Six had incomplete records and were excluded from the study, while 19 cases with complete records were available for analysis.

The patients were within the age range of 17 to 57years with the mean age of 32.2±11.7 years. Fifty- three percent of the participants were males with male to female ratio of 1.1:1, and all the cases were seen secondary to pain and swelling in relation to the teeth.

Figure 1 shows the distribution of teeth examined for periapical lesions within the study period, where all the affected teeth were upper incisors, with upper right central being the most affected (n=15; 39%) followed by upper left central. Majority (n=13; 68.4%) of the cases were clinically diagnosed to be periapical cyst, while majority (n=16; 84.2%) of the total cases were diagnosed histologically as being periapical granuloma (Table 1). However, only three (23.1%) out of the 13 clinically diagnosed periapical cystic lesions turned out to be periapical cyst on histopathology (p=0.2), while all the cases clinically diagnosed as periapical abscess or chronic apical periodontitis also had the histological diagnosis of periapical granuloma.

Figure 1. Distribution of teeth with periapical lesions .

Table 1. Analysis of the periapical pathology.

	Periapical granuloma		Periapical Cyst		Sensitivity	Specificity
	No	%	No	%
Radiographic /Clinical Result	6	31.6	13	68.4	33.3%	61.5%
Histopathology Result	16	84.2	3	15.8	100%	100%

When presence of sclerotic border was considered, only one (33.3%) of the cases of periapical cyst diagnosed by histology had a sclerotic border on radiograph, while nine out of 16 (56.3%) cases histologically diagnosed to be periapical granuloma had sclerotic border (p=0.5) as shown in Table 2.

Table 2. Comparison of Radiographic and Histology report on presence or absence of Sclerotic margin.

	Presence of sclerotic margin
	Radiographically		Histologically
	+ve	-ve	+ve	-ve
Periapical granuloma	0	6	9	7
Periapical Cyst	10	3	1	2
Total	10	9	10	9
p-value	0.003*		0.5
*Statistically significant

Nine (47.4%) out of the 19 cases had no sclerotic border radiographically out of which two were diagnosed to be periapical cyst histologically while only one out of 10 cases with sclerotic border was diagnosed to be cystic by histology. This however was not statistically significant (p=0.6).

Comparing the clinical diagnosis and radiographic presentation of presence of sclerotic border or not in diagnosis of periapical cyst, 10 cases (76.9%) out of 13 diagnosed clinically to be periapical cyst had sclerotic border with p=0.003 (Table 2 ).

Sensitivity and Specificity of Clinical/Radiograph compared with Histology.

Sensitivity of radiographs in detecting periapical cyst when compared with histology was found to be 33.3% while the specificity was 61.5%, while histology had 100% sensitivity and specificity.(Table 1) Further analysis done using Positive Predictive Value (PPV) and Negative Predictive Value (NPV) showed PPV for radiograph to be 12.5%, while the NPV was 56.3%. Diagnostic accuracy of conventional radiography detecting periapical cyst was 54.3% showing conventional radiography to be only a little above average in detecting periapical cyst.

Discussion

Periapical lesions resulting from necrotic dental pulp are among the most common pathologic conditions within alveolar bone, the majority being periapical cysts or granulomas. Diagnosis of these lesions frequently depends on conventional radiography and this is important in determining the treatment plan. The treatment could either be by non surgical root canal therapy (RCT) in most cases, or by surgical RCT, especially when it is necessary to remove the cystic lining of the lesion14. Based on the diagnostic acumen of dentists and specificity of the investigation, accurate diagnosis of the pathology is important to avoid needless treatments and also increase the patients’ confidence in the dentist.

According to a study15, 42.2% of cases in relation to periapical lesions: periapical granuloma, were misdiagnosed by endodontists while general dentist misdiagnosed 45.9% cases. This may however lead to unnecessary surgeries for the patient in a case that could have been treated with RCT.

The present study recorded a low number of cases (19) that fulfilled the inclusion criteria during the study period. This is in agreement with other studies 16,17 done in the same environment as the study center, and may be attributed to low submission of diseased periapical tissues for histology and a preference for extraction over RCT/apical surgery during the study period considered.

Majority of the teeth involved in this study were upper central teeth (Figure 1) which is in accordance with other studies18,19 that have found upper anteriors especially the central incisors being more affected and presenting more with periapical lesion. This may be due to the fact that these teeth are frequently involved in trauma both domestic and road traffic accidents, sports etc. and the slight male preponderance in this study is also in agreement with studies 18,20 that found more males with trauma to anterior teeth possibly due to their great involvement in sporting activities and other risky adventures.

The clinical/radiologic diagnosis of periapical cyst is based on the presence of a well defined cystic cavity 21,22. Majority (68.4%) of the cases studied were diagnosed as cystic lesion clinically. However on histology, majority (84.2%) of these lesions turned out to be periapical granuloma with only 15.8% of the lesions being cystic.(Table 1) This finding is in keeping with many studies18,19,23,24 that have found periapical granuloma presenting more than periapical cyst on histological examination of the lesions from periapical region. However Vier and Figueiredo25reported cystic lesion occurring more than granuloma in their study.

There was statistically significant difference (p=0.003) between clinical and radiographic diagnosis of periapical cyst when considered in view of presence or absence of sclerotic border, with majority (76.9%) of the clinically diagnosed periapical cyst having sclerotic border on radiograph. Thus for a clinical diagnosis of periapical cyst to be made, the presence of sclerotic border should be demonstrable on the radiograph. However, since only 33.3% of histologically diagnosed periapical cyst had sclerotic border on radiograph; while 56.3% of histologically diagnosed periapical granuloma had sclerotic border on radiograph, the presence of sclerotic border has only fair clinical diagnostic value, though not statistically significant with p= 0.5 (Table 2). This is to emphasize that presence of sclerotic border on radiograph is not enough to diagnose a periapical cyst because this could also affect the treatment plan for the tooth.

Furthermore, an author26 indicating a high level of confidence in the clinical diagnostic process has said that careful systematic clinical diagnosis will be adequate for treatment planning of periapical pathology, and that routine submission of endodontic surgical specimens is of no advantage to the patient. However, many studies27^-29 have shown the need to subject any periapical lesion after surgical removal to histological examination. The present study has further confirmed that histopathology is more sensitive compared to radiography in the diagnosis of periapical cysts and granulomas.

In this study, radiographs showed 33.3% sensitivity in diagnosing periapical cysts. This implies that it is a less precise form of investigation to diagnose periapical cysts but can averagely detect the periapical lesion as not being cystic with specificity of 61.5%. Also further analysis showed that conventional radiography can only predict presence of periapical cyst 12.5% of times while it will predict that a periapical lesion is not cystic in 56.3% of times, overall diagnostic accuracy of conventional radiograph was 54.3%, and this further confirms the low detecting ability of periapical cyst by conventional radiography. This result is in accordance with other studies2,27 that have found conventional radiograph a weak and relatively unreliable form of investigation in detecting periapical cyst. Thus periapical tissue after surgical removal should be submitted for histopathological review routinely to confirm the clinical diagnosis. This report is in accordance with the studies28,29 that have documented and emphasized the need to subject periapical tissues to histology for adequate diagnosis.

With advanced imaging that gives multiple field of view e.g. cone beam computed tomography (CBCT)30 giving better result by improving the visualization of the periapical region and lesion; better view of the root and the root canal in view of fractures and better view of the root morphology31, there is great improvement in diagnosis of periapical disease. Similarly, recent techniques of removing periapical lesions of pulpal origin and improving periapical healing using non surgical endodontics e.g use of apexum32 has aided the management of periapical disease through non surgical means. These recent advances in diagnostics would reduce performing unnecessary surgery following inadequate diagnosis of periapical lesions; help in resolving perplexity faced by the dentist in the assessment of the periapical region and also increases patients’ confidence in the dentist31.

Conclusions

Periapical lesions being the most frequently diagnosed apical pathology is mostly diagnosed using conventional radiography. This study showed that sensitivity and specificity of radiographs in detecting periapical lesions were reduced when compared with histology. However, considering the limitations and insufficiency of conventional radiography which may lead to misdiagnosis and unnecessary surgery for the patient, there is a need for advanced imaging to give improved quality of diagnosis, treatment planning and prognosis.