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Periapical and Endodontic Status Scale Based on Periapical Bone Lesions and Endodontic Treatment Quality Evaluation Using Cone-beam Computed Tomography
Clinical Research
Periapical and Endodontic Status Scale Based on Periapical Bone Lesions and Endodontic Treatment Quality Evaluation Using Cone-beam Computed Tomography Tadas Venskutonis, DDS, PhD,* Gianluca Plotino, DDS, PhD,† Luigi Tocci, DDS,† Gianluca Gambarini, MD, DDS,† Julius Maminskas, DDS,‡ and Gintaras Juodzbalys, DDS, PhD§ Abstract Introduction: The purpose of this study was to present a new periapical and endodontic status scale (PESS) that is based on the complex periapical index (COPI), which was designed for the identification and classification of periapical bone lesions in cases of apical periodontitis, and the endodontically treated tooth index, which was designed for endodontic treatment quality evaluation by means of cone-beam computed tomographic (CBCT) analysis. Methods: Periapical and endodontic status parameters were selected from the already known indexes and scientific literature for radiologic evaluation. Radiographic images (CBCT imaging, digital orthopantomography [DOR], and digital periapical radiography) from 55 patients were analyzed. All parameters were evaluated on CBCT, DOR, and digital periapical radiographic images by 2 external observers. The statistical analysis was performed with software SPSS version 19.0 (SPSS Inc, Chicago, IL). Chi-square tests were used to compare frequencies of qualitative variables. The level of significance was set at P # .05. Results: Overall intraobserver and interobserver agreements were very good and good, respectively. CBCT analysis found more lesions and lesions of bigger dimension (P < .001). CBCT imaging was also superior in locating lesions in the apical part on the side compared with DOR and in the diagnosis of cortical bone destruction compared with both methods (P < .001). Through CBCT analysis, more root canals and more canals associated with lesions were found. The most informative and reproducible periapical and endodontic status parameters were selected, and a new PESS was proposed. Conclusions: The classification proposed in the present study seems to be reproducible and objective and adds helpful information with respect to the existing indexes. Future studies need to be conducted to validate PESS. (J Endod 2015;41:190–196)
Key Words Cone-beam computed tomography, dental radiography, diagnosis, periapical index, treatment quality assessment, x-ray
T
he aim of endodontic epidemiology is primarily to evaluate the distribution and prevalence of apical periodontitis (AP) and its determinants, including treatment outcome in different populations (1). Various diagnostic indexes for periapical tissue evaluation were proposed using radiographic examination. Orstavik et al (2) developed the most popular periapical index (PAI); periapical lesions were classified into 5 scores based on the use of reference radiographs of teeth with a confirmed histologic diagnosis. Unfortunately, PAI is based on 2-dimensional periapical radiographs that attempt to analyze a 3-dimensional structure. Estrela et al (3) developed a periapical index (cone-beam computed tomographic [CBCT] PAI) based on criteria established from measurements corresponding to periapical radiolucency interpreted on CBCT scans. In both indexes, only image sizes and bone expansion or destruction (CBCTPAI) are evaluated. Such important information including the number of roots affected by AP, bone destruction related to anatomic structures such as the sinus floor, nerve canals, and the position of the lesion (apical, on the side, or furcation) are not evaluated. Endodontic status and technical quality of the root canal filling scale were developed by Eckerbom and Magnusson (4). The main criteria of the technical quality of the root canal filling are determined by the length and homogeneity of the root canal filling of visible tooth roots. All of the previously mentioned scales analyze separate nonsystematized parameters of the patient’s periapical and endodontic status. Furthermore, some parameters are expressed as morphologic changes of bone tissue but do not indicate the size of the lesion (2) or, on the other hand, give only the periapical bone lesion size in millimeters (3), which has only limited diagnostic and prognostic value. Previous studies showed that preoperative factors such as the presence of a lesion, its size, topography, and relationship to anatomic landmarks play an important role in the outcome of endodontic treatment (5, 6). Intraoperative factors such as coronal restoration quality, length, and homogeneity of the root canal filling and endodontic treatment complications might also influence the outcome of root canal treatment (5, 6). Furthermore, taking into account that CBCT imaging has better diagnostic characteristics, there are likely to be more cases of AP found compared with conventional radiographic systems (7). Therefore, there is still a need for new complex diagnostic periapical and endodontic status scale (PESS) development that is based on periapical lesion and intraoperative factor identification and assessment using
From the Departments of *Dental and Oral Diseases, ‡Prosthodontics, and §Maxillofacial Surgery, Lithuanian University of Health Sciences, Kaunas, Lithuania; and Department of Endodontics, Sapienza University of Rome, Rome, Italy. Address requests for reprints to Dr Tadas Venskutonis, Sauletekio 20, Domeikava 54350, Lithuania. E-mail address: [email protected] 0099-2399/$ - see front matter Copyright ª 2015 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2014.10.017
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Clinical Research diagnostic methods like CBCT imaging, which have introduced many potential benefits to clinical dentistry (8). The aim of this study was to present a new PESS that is based on the complex periapical index (COPI), which was designed for the identification and classification of periapical bone lesions in cases of AP, and the endodontically treated tooth index (ETTI), which was designed for endodontic treatment quality evaluation by means of CBCT analysis.
Materials and Methods To create a complex periapical and endodontic index, the radiologic diagnostic parameters, which might influence the prognosis of endodontic treatment outcome, were selected from the already known indexes and scientific literature. A pilot study was performed that sought to identify CBCT diagnostic possibilities in the assessment of the selected parameters. Digital orthopantomography (DOR) and digital periapical radiography (DPR) were used as conventional radiologic control methods. After data analyses and the final selection of optimal parameters, the PESS was proposed.
Patient Selection Radiographic images (CBCT, DOR, and DPR) from 185 patients were retrieved from the databases of the Department of Oral Diseases, Lithuanian University of Health Sciences, Kaunas, Lithuania. Examinations were performed between September 2008 and July 2013. In this retrospective cohort study, patients were selected according to the following inclusion criteria: (1) 2 radiologic diagnostic methods (CBCT and DOR [group 1] or CBCT and DPR [group 2]) performed within 1 month, (2) the quality of radiographic images sufficient for patient endodontic status assessment, and (3) at least 1 endodontically treated tooth present. Images from 55 patients (group 1: n = 35, group 2: n = 20) met those criteria and were selected for further evaluation. The local ethics committee in Kaunas approved the study. PESS Creation Strategy PESS should be based on 2 indexes: COPI, which was designed for radiologic identification and classification of periapical bone lesions in cases of AP, and ETTI, which was designed for endodontic treatment quality radiologic evaluation. All parameters were evaluated on CBCT and DOR or DPR images. DPR and DOR were used as conventional radiologic control methods to compare examination results with CBCT examination. CBCT and DOR images were taken using an i-CAT CBCT device (Imaging Sciences International, Inc, Hatfield, PA; 120 kVp, 3–8 mA); DPR images were taken using a digital radiographic system (Kodak RVG 6100; Carestream Health, Rochester, NY; 70 kV, 4 mA, exposure time of 0.11–0.19 seconds).
COPI Parameter Selection The principle of the selection of COPI parameters was based on available data concerning prognostic factors of periapical radiolucency characteristics in the endodontic therapy of teeth with AP. The planned periapical index will be composed of 3 parameters that are related to the characteristics of the periapical lesion: (1) the size of the lesion (S), which may be directly related to endodontic treatment outcome results (6, 9); (2) the relationship between the root and the lesion (R), which is an important pretreatment factor because the outcome of endodontic lesion treatment on multirooted teeth is worse (10, 11); and (3) the location of bone destruction (D), which can be related to more complicated endodontic or surgical treatment because of the contact of radiolucency with important anatomic structures or the destruction of cortical bone (12, 13). S, depending on the size, comprises 3 parameters (6, 9, 14): S0: widening of the periodontal JOE — Volume 41, Number 2, February 2015
ligament not to exceed 2 times the width of the lateral periodontal ligament; S1: small, well-defined radiolucency up to 3 mm in diameter; and S2: large well-defined radiolucency >3 mm in diameter. R, meanwhile, will be composed of 6 parameters (10, 11, 15): R0: no radiolucency, when widening of the periodontal ligament does not exceed 2 times the width of the lateral periodontal ligament; R1: a radiolucent lesion appears on 1 root; R2: radiolucent lesions appear on 2 roots; R3: radiolucent lesions appear on more than 2 roots; R4: 2 or more radiolucent lesions are connected; and R5: a radiolucent lesion with involvement of furcation. D, depending on the extension of the lesion, will be composed of 6 parameters (12, 13): D0: no radiolucency, when widening of the periodontal ligament does not exceed 2 times the width of the lateral periodontal ligament; D1: radiolucency surrounds the apical part of the root; D2: radiolucency on the side or deviates to the side of the root; D3: radiolucency in contact with important anatomic structures; D4: expansion of the cortical bone; and D5: a radiolucent lesion with involvement of furcation.
ETTI Parameter Selection ETTI will be derived from 4 endodontic treatment assessment explanatory parameters, which are important to the prediction of treatment outcome: 1. Length of the root canal filling (L), which is measured in terms of the distance between the apical end of the visible filling material until the radiographic terminus of the root; it will be composed of 5 parameters (4, 16, 17): L1: 0–2 mm, L2: $2 mm, L3: overfilling (extrusion of material through the apex), L4: filling material visible only in pulp chamber, and L5: filled canal of a surgically treated root. 2. Homogeneity of the root canal fillings (H), which is an important factor in judging filling condensation. It also takes into consideration the presence of posts because it may play an important role in treatment outcome (4, 17). H consists of 4 parameters: H1: complete obturation (homogenous appearance of the root canal filling), H2: incomplete obturation (voids and porous appearance of the root canal filling), H3: post in the root canal with adequate filling (homogenous appearance of the root canal filling), and H4: post in the root canal with inadequate filling (voids and porous appearance of the root canal filling). 3. Coronal seal (CS), which may play a role in improving treatment outcome (5, 6, 17). CS consists of 3 parameters: CS1: adequate (coronal restoration appears intact radiographically), CS2: inadequate (detectable radiographic signs of overhangs, open margins, recurrent caries, or loss of coronal restoration), and CS3: undetermined (impossible to evaluate because of artifacts). 4. Presence of complications/failures (CF) can significantly influence the prognosis (5, 6, 17). For this reason, the evaluation of different complications was included. CF consists of 10 parameters: CF0: no complications, CF1: root perforation, CF2: root canal not treated/missed, CF3: internal resorption without perforation, CF4: internal resorption with perforation, CF5: apical resorption, CF6: root/tooth fracture, CF7: canal obstruction (ledge, broken instrument, and denticle), CF8: surgically treated root with bone radiolucency, and CF9: endodontically treated root with radiolucency.
Evaluation of the Results of Radiographic Examination CBCT, DOR, and DPR images were analyzed with i-CAT viewing software (Imaging Sciences International, Inc) and Kodak dental Periapical and Endodontic Status Scale
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Clinical Research imaging software version 6.12.11.0 (Carestream Dental LLC). Crosssectional CBCT images were analyzed in 3 planes (sagittal, coronal, and axial). The filters were set to normal, and only brightness and contrast were adjusted. Images were analyzed on a 27-inch flat-panel display screen with a pixel resolution of 2560 1440 in a dimly lit room without time restrictions. Two external observers (both endodontists) were calibrated and examined the images separately. They were instructed to examine CBCT, DOR, and DPR images and grade their observations using PESS index parameters. The first evaluation was performed on CBCT scans; then, 2 weeks later, either DOR or DPR images were examined. One month later, the evaluation was repeated. The overall kappa index for interobserver and intraobserver agreement was calculated by using a weighted kappa. In case of disagreement, the case was discussed, and a consensus was reached. During their evaluation, observers were looking for teeth that were endodontically treated or had periapical lesions. One COPI score was written for each tooth. The measurement of the lesions was performed in 3 planes (axial, frontal, and sagittal), and the widest distance was registered. If more than 1 root had a lesion, the biggest was considered, and the S component score was determined. For the ETTI part, all canals of the tooth were graded separately, except for the CS for which only 1 score per tooth was assigned. For untreated teeth with periapical radiolucency, only the COPI part of the index was evaluated. If the treatment on the tooth was performed between taking the images, the tooth was excluded.
Statistical Analysis The statistical analysis was performed with SPSS software version 19.0 (SPSS, Inc, Chicago, IL). Significance was set at a P value of .05 or less. All parametric data were expressed as the mean and standard deviation (SD) or the mean and 95% confidence interval. Chi-square tests were used to compare frequencies of qualitative variables. The level of significance was set at P # .05. Agreement between the measurements was evaluated by weighted kappa.
Results In group 1 (mean age = 48.6 [SD = 11.8] years, 31% men and 69% women), a total of 817 teeth (mean = 23.34 [SD = 6.08]), 187 of them endodontically treated (mean = 5.34 [SD = 3.93])
(101 in the upper jaw and 81 in the lower jaw), were analyzed. The distribution of the teeth (66 anterior, 57 premolar, and 64 molar teeth) is equal (by goodness-of-fit test, c22 = 1.08, P = .58). The power of the study is 0.78. In group 2 (mean age = 42.4 [SD = 12.1] years, 65% men and 35% women), a total of 35 endodontically treated teeth (1.75 [SD = 0.91], 27 in the maxilla and 8 in the mandible) were evaluated. The distribution of the teeth (11 anterior, 11 premolar, and 13 molar teeth) was equal (P > .05). The calculated power of the sample was 0.86.
COPI All intra- and interobserver COPI index kappa coefficient scores for all radiologic examination methods were good or very good, except the interobserver agreement scores for CBCT and DPR, which were moderate in the D4 group, and for DOR in the D2, D3, and D4 groups. Table 1 presents an overview of the results of the COPI index. CBCT analysis found more, and larger, lesions (S1 and S2) (P # .05). The relationship between the root and the lesion was more complicated in group 1 (R1–R5) (c25 = 28.36, P < .001) but not significantly different in group 2. In group 1, CBCT imaging was superior in locating lesions in the apical part (D1) (P < .001) and on the side (D2) (P < .001) and in diagnosing cortical bone expansion (D4) (P = .029) and cortical bone destruction (D5) (P < .001). In group 2, CBCT imaging was superior in the diagnosis of a lesion near anatomic landmarks (D3) (P < .05) and cortical bone expansion (D5) (P < .001). ETTI All intra- and interobserver ETTI index kappa coefficient scores for all radiologic examination methods were good or very good, except the interobserver agreement scores, which were moderate for CBCT in the H and CS groups, for DPR in the CS group, and for DOR in the CS, CF1, CF7, and CF9 groups. Table 2 presents an overview of the results of the ETTI index. There were no differences between all methods of investigation regarding the length of the root canal filling, H, and CS. Furthermore, there was no correlation between the quality of the CS and the presence of an endodontic lesion (S1 and S2) (P = .12). Only a few cases of root resorption and surgically treated teeth were registered in group 2 (Table 2). Through CBCT analysis, more root canals (363) were found compared with DOR analysis (303) (P < .001), but no significant
TABLE 1. Results of the Complex Periapical Diagnostic Index of Using Cone-beam Computed Tomographic, Digital Orthopantomography, and Digital Periapical Radiography
Parameter S0 S1 S2 R0 R1 R2 R3 R4 R5 D0 D1 D2 D3 D4 D5
Examination method
Examination method
n = 187 teeth
n = 35 teeth
CBCT
DOR
c2 test and P value
CBCT
DPR
c2 test and P value
77 67 43 77 79 12 3 10 6 77 103 32 11 11 17
126 44 17 126 44 9 3 4 1 126 60 10 6 3 0
c22 = 27.86, P < .001
10 10 15 10 12 2 1 9 1 10 24 15 13 7 12
19 4 12 19 7 3 0 5 1 19 16 10 3 3 0
c22 = 5.70, P = .05
c25 = 28.36, P < .001
P < .001 P < .001 P < .001 P > .05 P = .029 P < .001
c25 = 6.45, P > .05
P < .05 P > .05 P > .05 P < .05 P > .05 P < .001
CBCT, cone-beam computed tomography; COPI, complex periapical index; DOR, digital orthopantomography; DPR, digital periapical radiography.
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Clinical Research TABLE 2. Results of the Endodontically Treated Tooth Diagnostic Index: CBCT, DOR, and DPR Examination method
Examination method Parameter L1 L2 L3 L4 L5 H1 H2 H3 H4 CS1 CS2 CS3 CF1 CF2 CF3 CF4 CF5 CF6 CF7 CF8 CF9
CBCT
DOR
c test and P value
CBCT
DPR
c2 test and P value
197 89 14 46 0 129 101 90 26 38 24 116 4 44 0 0 0 2 82 0 188
175 75 12 27 0 100 87 66 36 52 31 95 2 23 0 0 0 1 71 0 78
c23 = 2.50, df-3, P > .05
49 10 7 2 2 44 14 8 3 16 5 14 2 2 0 1 — — 10 2 42
48 10 5 1 2 42 16 7 1 14 8 11 2 1 1 0 — — 9 2 23
c24 = 0.56, P > .05
2
c23 = 4.94, P > .05
c22 = 5.45, P > .05 P > .05 P = .05 — — — P > .05 P > .05 — P < .001
c23 = 1.18, P > .05
c22 = 1.13, P > .05 P > .05 P > .05 P > .05 P > .05 — — P > .05 P > .05 P < .05
CBCT, cone-beam computed tomography; DOR, digital orthopantomography; DPR, digital periapical radiography.
differences were found in group 2 (CBCT = 74, DPR = 68). In group 1, CBCT imaging found significantly more missed canals (CF2) and more canals associated with lesions (CF9). CBCT imaging enhanced the frequency of diagnosis for some factors (CF1, CF6, and CF7) but without a statistically significant difference. In group 2, because of a low number of teeth, CBCT scanning was only superior in the detection of canals associated with lesions (CF9).
When groups H1 with H2, and H3 with H4 were compared, a post inside the canal did not make any difference (P > .05). A positive correlation was detected between the length of the root canal filling and the presence of an endodontic lesion for all methods of evaluation (P < .05). When analyzing homogeneity of the root canal filling, only CBCT imaging detected a positive correlation with the presence of an endodontic lesion (P = .042). Perforations (CF1), missed canals
Figure 1. The new Complex Periapical Index (COPI) designed for identification and classification of periapical bone lesions in case of apical periodontitis: S, R, and D evaluation scale.
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Clinical Research (CF2), and canal obstruction (CF7) were positively associated with the presence of endodontic lesions (P < .05).
Discussion AP is a disease; its main symptom is bone destruction. AP may be detected with conventional radiography only 15 to 30 days after the development of the disease (18, 19). However, with new technologies like CBCT imaging, it is possible to detect AP as soon as 7 days after it develops (18). AP detection and characterization represent an important preoperative factor that may influence the outcome of root canal treatment; thus, early diagnosis is essential (5, 6, 10). Orstavik et al (2) developed the most popular PAI in which periapical lesions were classified into 5 scores. It is based on a 2-dimensional (2D) radiologic method and cannot be applied to 3-dimensional imaging; furthermore, the original study was done only on upper front teeth and is not based on clinical outcomes, and thus the prognostic value is unknown. Tooth type, number of roots, size and number of lesions, and their location are known to influence treatment prognosis (6, 9–12, 14, 15), but these parameters cannot be assessed using PAI. The other index, called CBCTPAI and developed by Estrela, is based on 3dimensional image interpretation, but only lesion size, plus 2 additional variables of cortical bone expansion and destruction, are analyzed (3); some previously mentioned important parameters are not assessed. There is no such index that implements the all-important aspect of periapical pathosis; moreover, there is a lack of a complex index in which radiologic treatment results can be accessed. It is known from previous studies that length of root canal filling, homogeneity, CS, and existing complications all influence endodontic treatment outcome (4–6, 16, 17), and the parameters proposed by Eckerbom and Magnusson for endodontic treatment evaluation are not complete (4). Most importantly, preoperative, intraoperative, and postoperative parameters included in this study were gathered from previous scientific studies. A pilot study was conducted to evaluate which parameters are possible to evaluate using CBCT imaging, and the results were compared with the control methods (DOR and DPR). The results of the pilot study revealed that the analysis conducted for group 1 and group 2 showed very good overall intraobserver agreement and good interobserver agreement. CBCT image analysis resulted in a higher detection rate for AP than conventional radiography. AP was detected in 32.6%, 45.7%, and 58.8%–71.4% of the teeth by using DOR, DPR, and CBCT imaging, respectively. CBCT imaging also detected larger lesions (S2) than conventional radiography (CBCT = 23%, DOR = 9%, P = .001; CBCT = 43%, DPR = 34%, P = .05). Prevalence of AP might be higher in terms of what could be obtained from 2D radiographic images. Even when lesions are small or are not in an advanced stage, CBCT imaging showed better diagnostic results (20–23). The results obtained in the present study are similar to those from other clinical studies, which suggested that radiologic findings obtained from CBCT imaging may represent the ‘‘true’’ status of the periapical tissues (16, 24). CBCT imaging may also give some false-positive results, but even in a study that used histopathological findings as the ‘‘gold standard,’’ CBCT scans were more sensitive in detecting AP compared with 2D radiography, which was more likely to miss AP when it was still present (25). A limitation of the present study may be that the dynamics of AP cannot be judged. In fact, some of the AP lesions registered might be healing from a previous, bigger, lesion; repeating the analysis in different periods of time may reveal this. If AP is present on several roots in a multirooted tooth, the outcome might be different (11). The present study showed that CBCT imaging revealed a more complicated rootlesion relationship. In group 2, the difference was not significant because of the low number of teeth. Using the conventional indexes, 194
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this information was not analyzed at all. The location and severity of the lesions, such as expansion or destruction of cortical bone, as well as contact with the sinus or the mandibular canal are also more easily missed using conventional radiology (12, 13). The present study revealed similar results; CBCT imaging was superior in detecting lesions in the apical (D1) and lateral areas (D2), expansion (D4) and destruction of cortical bone (D5) in group 1, and diagnosing the contact of the lesion with important anatomic structures (D3) and destruction of cortical bone (D5) in group 2. Analyzing the results of the present study, it was decided to make the COPI index easier and more informative as well as to group each parameter (S, R, and D) into 3 different treatment risks: mild (green color), moderate (yellow color), and high (red color) (Fig. 1). Several studies suggested that lesions more than 5 mm in size may strongly influence prognosis of the treatment (6, 17), so it was decided to include a third score for the S parameter (S3: diameter of large well-defined radiolucency >5 mm) (Fig. 1). For the R evaluation, parameter variations R2, R3, and R4 were joined to only 1 parameter R2 (radiolucent lesion appears on more than 1 root) to better reflect the outcome of multirooted teeth (Fig. 1). For the D evaluation, it was decided to join D1 and D2 into 1 new category, D1 (radiolucency around the root), and to eliminate D4 because intraobserver kappa was moderate (Fig. 1). Each component of the index (S, R, and D) is described independently. D can be described by several components at the same time (eg, COPI S1R1D1 [Fig. 2] or S2R2D1,2 [Fig. 3]). In the present study, the lack of clinical information and scatter and beam hardening caused by high-density neighboring structures and materials were the reasons for the moderate interobserver kappa coefficient for CS and homogeneity through CBCT evaluation. These artifacts did not allow us to fully evaluate the adaptation of the crown and root filling material (26, 27). In the present study, when analyzing canal
Figure 2. An example of the PESS diagnostic index using CBCT imaging of the sagittal plane of the upper cuspid with a radiolucent lesion.
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Clinical Research
Figure 3. An example of the PESS diagnostic index: CBCT imaging of the upper first molar. (A) Frontal plane, palatal root with a radiolucent lesion; (B) frontal plane, distobuccal root; (C) frontal plane mesiobuccal, root and missed mesiobuccal second canal; (D) axial plane, missed mesiobuccal second canal; and (E) sagittal plane, mesiobuccal second canal with radiolucency.
filling length, homogeneity, or CS, all methods of radiologic evaluation registered the same good results without any statistical difference. The presence of a root canal post did not influence the detection of AP, as reported in previously published research (17, 28). Several studies were conducted on the ability of CBCT scanning to detect root canal treatment complications, such as resorptions, perforations, and vertical and horizontal root fractures (29–31). In the present study, the superiority of CBCT imaging to detect missed canals (CF2) and bone lesions (CF9) has been confirmed, even if no
cases of resorption (CF3–CF5) and few cases of root canal perforations (CF1), root fractures (CF6), and roots that underwent endodontic surgery (CF8) were registered (Table 2). Upon analyzing the results of the present study, it was decided to also make the ETTI index easier and to select its final parameters. Because the presence of a post inside the canal did not make any difference, grades H3 and H4 were removed from the final index (Table 3). The CS3 (undetermined) parameter was removed in the final index because there were no clinical data available, which is essential
TABLE 3. The New Endodontically Treated Tooth Index: L, H, CS, and CF Evaluation Scale L (length of the root canal filling) L1 0–2 mm from radiographic apex L2 >2 mm from radiographic apex L3 Overfilling (extrusion of material through the apex) L4 Filling material visible only in pulp chamber L5 Filled canal of a surgically treated root. H (homogeneity of the root canal fillings) H1 Complete obturation (homogenous appearance of the root canal filling) H2 Incomplete obturation (voids and porous appearance of the root canal filling) CS (coronal seal) CS1 Adequate (coronal restoration appears intact radiographically) CS2 Inadequate (detectable radiographic signs of overhangs, open margins, recurrent caries, or lost coronal restoration) CF (complications/failures) CF0 No complications CF3 Root resorption CF1 Root perforation CF4 Root/tooth fracture CF2 Root canal not treated/missed CF5 Endodontically treated root with radiolucency
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Clinical Research for judging CS. For the complication/failure parameters, it was decided to join all resorption parameters (CF3, CF4, and CF5) into 1 final parameter, CF3 (root resorption), and remove CF7 (canal obstruction) and CF8 (surgically treated root with bone radiolucency) because it is possible to get this data from the other parameter grades (Table 3). Each component of ETTI is described independently. For example, ETTI of a 1-rooted tooth is expressed as L1H1CS2CF5 (Fig. 2), whereas the ETTI of a multirooted tooth (ie, the palatal canal) is expressed as L1H1CS2CF5 (Fig. 3). CF can also be described by several parameters at the same time (ie, L2H2CS2CF1,5 and L1H1CS1CF4,5). The newly developed PESS index described in the present study is complex and different from all other indexes already present in the literature. It allows the evaluation of not only the status of periapical tissues but also endodontic treatment quality. Furthermore, the COPI periapical index has prognostic value because of its suggested AP treatment risk degrees. PESS can be used in epidemiological studies and clinical practice. Future research must validate it in large multicenter clinical studies, with a higher number of examiners and patients. Patients should be followed up for at least 2 years to validate the significance of parameter variations. Finally, if universally adopted, this system of evaluation might allow groups worldwide to calibrate and build powerful combined data.
Conclusion The classification proposed in the present study for the evaluation of periapical status and endodontic treatment quality seems to be reproducible and objective and adds helpful information to the existing indexes. Future studies need to be conducted to validate PESS.
Acknowledgments The authors deny any conflicts of interest related to this study.
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10. Patel S, Wilson R, Dawood A, et al. The detection of periapical pathosis using digital periapical radiography and cone beam computed tomography—part 2: a 1-year post-treatment follow-up. Int Endod J 2012;8:711–23. 11. de Chevigny C, Dao TT, Basrani BR, et al. Treatment outcome in endodontics: the Toronto study—phase 4: initial treatment. J Endod 2008;3:258–63. 12. Shahbazian M, Vandewoude C, Wyatt J, Jacobs R. Comparative assessment of periapical radiography and CBCT imaging for radiodiagnostics in the posterior maxilla. Odontology 2013 Dec 28. [Epub ahead of print]. 13. Low KMT, Dula K, B€urgin W, Arx von T. Comparison of periapical radiography and limited cone-beam tomography in posterior maxillary teeth referred for apical surgery. J Endod 2008;5:557–62. 14. Bornstein MM, Lauber R, Sendi P, Arx von T. Comparison of periapical radiography and limited cone-beam computed tomography in mandibular molars for analysis of anatomical landmarks before apical surgery. J Endod 2011;2: 151–7. 15. Arx von T, Pe~narrocha M, Jensen S. Prognostic factors in apical surgery with rootend filling: a meta-analysis. J Endod 2010;6:957–73. 16. Moura MS, Guedes OA, de Alencar AHG, et al. Influence of length of root canal obturation on apical periodontitis detected by periapical radiography and cone beam computed tomography. J Endod 2009;6:805–9. 17. Ricucci D, Russo J, Rutberg M, et al. A prospective cohort study of endodontic treatments of 1,369 root canals: results after 5 years. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;6:825–42. 18. Jorge EG, Tanomaru-Filho M, Gonc¸alves M, Tanomaru JMG. Detection of periapical lesion development by conventional radiography or computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;1:e56–61. 19. De Rossi A, De Rossi M, Rocha LB, et al. Morphometric analysis of experimentally induced periapical lesions: radiographic vs histopathological findings. Dentomaxillofac Radiol 2007;4:211–7. 20. Sogur E, Gr€ondahl HG, Baksı BG, Mert A. Does a combination of two radiographs increase accuracy in detecting acid-induced periapical lesions and does it approach the accuracy of cone-beam computed tomography scanning? J Endod 2012;2:131–6. 21. Sogur E, Baksi BG, Gr€ondahl HG, et al. Detectability of chemically induced periapical lesions by limited cone beam computed tomography, intra-oral digital and conventional film radiography. Dentomaxillofac Radiol 2009;7:458–64. 22. Tsai P, Torabinejad M, Rice D, Azevedo B. Accuracy of cone-beam computed tomography and periapical radiography in detecting small periapical lesions. J Endod 2012;7:965–70. 23. Kamburoglu K, Kilic C, Ozen T, Horasan S. Accuracy of chemically created periapical lesion measurements using limited cone beam computed tomography. Dentomaxillofac Radiol 2010;2:95–9. 24. Abella F, Patel S, Duran Sindreu F, et al. An evaluation of the periapical status of teeth with necrotic pulps using periapical radiography and cone-beam computed tomography. Int Endod J 2014;4:387–96. 25. Paula-Silva FWG, Wu M-K, Leonardo MR, et al. Accuracy of periapical radiography and cone-beam computed tomography scans in diagnosing apical periodontitis using histopathological findings as a gold standard. J Endod 2009;7: 1009–12. 26. Ritter L, Mischkowski RA, Neugebauer J, et al. The influence of body mass index, age, implants, and dental restorations on image quality of cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;3:e108–16. 27. Liang Y-H, Li G, Wesselink PR, Wu M-K. Endodontic outcome predictors identified with periapical radiographs and cone-beam computed tomography scans. J Endod 2011;3:326–31. 28. Hommez GMG, Coppens CRM, De Moor RJG. Periapical health related to the quality of coronal restorations and root fillings. Int Endod J 2002;8:680–9. 29. Long H, Zhou Y, Ye N, et al. Diagnostic accuracy of CBCT for tooth fractures: a metaanalysis. J Dent 2014;3:240–8. 30. Venskutonis T, Juodzbalys G, Nackaerts O, Mickevicien_e L. Influence of voxel size on the diagnostic ability of cone-beam computed tomography to evaluate simulated root perforations. Oral Radiol 2013;2:151–9. 31. Bernardes RA, de Paulo RS, Pereira LO, et al. Comparative study of cone beam computed tomography and intraoral periapical radiographs in diagnosis of lingual-simulated external root resorptions. Dent Traumatol 2012;4: 268–72.
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Periapical and Endodontic Status Scale Based on Periapical Bone Lesions and Endodontic Treatment Quality Evaluation Using Cone-beam Computed Tomography Tadas Venskutonis, DDS, PhD,* Gianluca Plotino, DDS, PhD,† Luigi Tocci, DDS,† Gianluca Gambarini, MD, DDS,† Julius Maminskas, DDS,‡ and Gintaras Juodzbalys, DDS, PhD§ Abstract Introduction: The purpose of this study was to present a new periapical and endodontic status scale (PESS) that is based on the complex periapical index (COPI), which was designed for the identification and classification of periapical bone lesions in cases of apical periodontitis, and the endodontically treated tooth index, which was designed for endodontic treatment quality evaluation by means of cone-beam computed tomographic (CBCT) analysis. Methods: Periapical and endodontic status parameters were selected from the already known indexes and scientific literature for radiologic evaluation. Radiographic images (CBCT imaging, digital orthopantomography [DOR], and digital periapical radiography) from 55 patients were analyzed. All parameters were evaluated on CBCT, DOR, and digital periapical radiographic images by 2 external observers. The statistical analysis was performed with software SPSS version 19.0 (SPSS Inc, Chicago, IL). Chi-square tests were used to compare frequencies of qualitative variables. The level of significance was set at P # .05. Results: Overall intraobserver and interobserver agreements were very good and good, respectively. CBCT analysis found more lesions and lesions of bigger dimension (P < .001). CBCT imaging was also superior in locating lesions in the apical part on the side compared with DOR and in the diagnosis of cortical bone destruction compared with both methods (P < .001). Through CBCT analysis, more root canals and more canals associated with lesions were found. The most informative and reproducible periapical and endodontic status parameters were selected, and a new PESS was proposed. Conclusions: The classification proposed in the present study seems to be reproducible and objective and adds helpful information with respect to the existing indexes. Future studies need to be conducted to validate PESS. (J Endod 2015;41:190–196)
Key Words Cone-beam computed tomography, dental radiography, diagnosis, periapical index, treatment quality assessment, x-ray
T
he aim of endodontic epidemiology is primarily to evaluate the distribution and prevalence of apical periodontitis (AP) and its determinants, including treatment outcome in different populations (1). Various diagnostic indexes for periapical tissue evaluation were proposed using radiographic examination. Orstavik et al (2) developed the most popular periapical index (PAI); periapical lesions were classified into 5 scores based on the use of reference radiographs of teeth with a confirmed histologic diagnosis. Unfortunately, PAI is based on 2-dimensional periapical radiographs that attempt to analyze a 3-dimensional structure. Estrela et al (3) developed a periapical index (cone-beam computed tomographic [CBCT] PAI) based on criteria established from measurements corresponding to periapical radiolucency interpreted on CBCT scans. In both indexes, only image sizes and bone expansion or destruction (CBCTPAI) are evaluated. Such important information including the number of roots affected by AP, bone destruction related to anatomic structures such as the sinus floor, nerve canals, and the position of the lesion (apical, on the side, or furcation) are not evaluated. Endodontic status and technical quality of the root canal filling scale were developed by Eckerbom and Magnusson (4). The main criteria of the technical quality of the root canal filling are determined by the length and homogeneity of the root canal filling of visible tooth roots. All of the previously mentioned scales analyze separate nonsystematized parameters of the patient’s periapical and endodontic status. Furthermore, some parameters are expressed as morphologic changes of bone tissue but do not indicate the size of the lesion (2) or, on the other hand, give only the periapical bone lesion size in millimeters (3), which has only limited diagnostic and prognostic value. Previous studies showed that preoperative factors such as the presence of a lesion, its size, topography, and relationship to anatomic landmarks play an important role in the outcome of endodontic treatment (5, 6). Intraoperative factors such as coronal restoration quality, length, and homogeneity of the root canal filling and endodontic treatment complications might also influence the outcome of root canal treatment (5, 6). Furthermore, taking into account that CBCT imaging has better diagnostic characteristics, there are likely to be more cases of AP found compared with conventional radiographic systems (7). Therefore, there is still a need for new complex diagnostic periapical and endodontic status scale (PESS) development that is based on periapical lesion and intraoperative factor identification and assessment using
From the Departments of *Dental and Oral Diseases, ‡Prosthodontics, and §Maxillofacial Surgery, Lithuanian University of Health Sciences, Kaunas, Lithuania; and Department of Endodontics, Sapienza University of Rome, Rome, Italy. Address requests for reprints to Dr Tadas Venskutonis, Sauletekio 20, Domeikava 54350, Lithuania. E-mail address: [email protected] 0099-2399/$ - see front matter Copyright ª 2015 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2014.10.017
†
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Clinical Research diagnostic methods like CBCT imaging, which have introduced many potential benefits to clinical dentistry (8). The aim of this study was to present a new PESS that is based on the complex periapical index (COPI), which was designed for the identification and classification of periapical bone lesions in cases of AP, and the endodontically treated tooth index (ETTI), which was designed for endodontic treatment quality evaluation by means of CBCT analysis.
Materials and Methods To create a complex periapical and endodontic index, the radiologic diagnostic parameters, which might influence the prognosis of endodontic treatment outcome, were selected from the already known indexes and scientific literature. A pilot study was performed that sought to identify CBCT diagnostic possibilities in the assessment of the selected parameters. Digital orthopantomography (DOR) and digital periapical radiography (DPR) were used as conventional radiologic control methods. After data analyses and the final selection of optimal parameters, the PESS was proposed.
Patient Selection Radiographic images (CBCT, DOR, and DPR) from 185 patients were retrieved from the databases of the Department of Oral Diseases, Lithuanian University of Health Sciences, Kaunas, Lithuania. Examinations were performed between September 2008 and July 2013. In this retrospective cohort study, patients were selected according to the following inclusion criteria: (1) 2 radiologic diagnostic methods (CBCT and DOR [group 1] or CBCT and DPR [group 2]) performed within 1 month, (2) the quality of radiographic images sufficient for patient endodontic status assessment, and (3) at least 1 endodontically treated tooth present. Images from 55 patients (group 1: n = 35, group 2: n = 20) met those criteria and were selected for further evaluation. The local ethics committee in Kaunas approved the study. PESS Creation Strategy PESS should be based on 2 indexes: COPI, which was designed for radiologic identification and classification of periapical bone lesions in cases of AP, and ETTI, which was designed for endodontic treatment quality radiologic evaluation. All parameters were evaluated on CBCT and DOR or DPR images. DPR and DOR were used as conventional radiologic control methods to compare examination results with CBCT examination. CBCT and DOR images were taken using an i-CAT CBCT device (Imaging Sciences International, Inc, Hatfield, PA; 120 kVp, 3–8 mA); DPR images were taken using a digital radiographic system (Kodak RVG 6100; Carestream Health, Rochester, NY; 70 kV, 4 mA, exposure time of 0.11–0.19 seconds).
COPI Parameter Selection The principle of the selection of COPI parameters was based on available data concerning prognostic factors of periapical radiolucency characteristics in the endodontic therapy of teeth with AP. The planned periapical index will be composed of 3 parameters that are related to the characteristics of the periapical lesion: (1) the size of the lesion (S), which may be directly related to endodontic treatment outcome results (6, 9); (2) the relationship between the root and the lesion (R), which is an important pretreatment factor because the outcome of endodontic lesion treatment on multirooted teeth is worse (10, 11); and (3) the location of bone destruction (D), which can be related to more complicated endodontic or surgical treatment because of the contact of radiolucency with important anatomic structures or the destruction of cortical bone (12, 13). S, depending on the size, comprises 3 parameters (6, 9, 14): S0: widening of the periodontal JOE — Volume 41, Number 2, February 2015
ligament not to exceed 2 times the width of the lateral periodontal ligament; S1: small, well-defined radiolucency up to 3 mm in diameter; and S2: large well-defined radiolucency >3 mm in diameter. R, meanwhile, will be composed of 6 parameters (10, 11, 15): R0: no radiolucency, when widening of the periodontal ligament does not exceed 2 times the width of the lateral periodontal ligament; R1: a radiolucent lesion appears on 1 root; R2: radiolucent lesions appear on 2 roots; R3: radiolucent lesions appear on more than 2 roots; R4: 2 or more radiolucent lesions are connected; and R5: a radiolucent lesion with involvement of furcation. D, depending on the extension of the lesion, will be composed of 6 parameters (12, 13): D0: no radiolucency, when widening of the periodontal ligament does not exceed 2 times the width of the lateral periodontal ligament; D1: radiolucency surrounds the apical part of the root; D2: radiolucency on the side or deviates to the side of the root; D3: radiolucency in contact with important anatomic structures; D4: expansion of the cortical bone; and D5: a radiolucent lesion with involvement of furcation.
ETTI Parameter Selection ETTI will be derived from 4 endodontic treatment assessment explanatory parameters, which are important to the prediction of treatment outcome: 1. Length of the root canal filling (L), which is measured in terms of the distance between the apical end of the visible filling material until the radiographic terminus of the root; it will be composed of 5 parameters (4, 16, 17): L1: 0–2 mm, L2: $2 mm, L3: overfilling (extrusion of material through the apex), L4: filling material visible only in pulp chamber, and L5: filled canal of a surgically treated root. 2. Homogeneity of the root canal fillings (H), which is an important factor in judging filling condensation. It also takes into consideration the presence of posts because it may play an important role in treatment outcome (4, 17). H consists of 4 parameters: H1: complete obturation (homogenous appearance of the root canal filling), H2: incomplete obturation (voids and porous appearance of the root canal filling), H3: post in the root canal with adequate filling (homogenous appearance of the root canal filling), and H4: post in the root canal with inadequate filling (voids and porous appearance of the root canal filling). 3. Coronal seal (CS), which may play a role in improving treatment outcome (5, 6, 17). CS consists of 3 parameters: CS1: adequate (coronal restoration appears intact radiographically), CS2: inadequate (detectable radiographic signs of overhangs, open margins, recurrent caries, or loss of coronal restoration), and CS3: undetermined (impossible to evaluate because of artifacts). 4. Presence of complications/failures (CF) can significantly influence the prognosis (5, 6, 17). For this reason, the evaluation of different complications was included. CF consists of 10 parameters: CF0: no complications, CF1: root perforation, CF2: root canal not treated/missed, CF3: internal resorption without perforation, CF4: internal resorption with perforation, CF5: apical resorption, CF6: root/tooth fracture, CF7: canal obstruction (ledge, broken instrument, and denticle), CF8: surgically treated root with bone radiolucency, and CF9: endodontically treated root with radiolucency.
Evaluation of the Results of Radiographic Examination CBCT, DOR, and DPR images were analyzed with i-CAT viewing software (Imaging Sciences International, Inc) and Kodak dental Periapical and Endodontic Status Scale
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Clinical Research imaging software version 6.12.11.0 (Carestream Dental LLC). Crosssectional CBCT images were analyzed in 3 planes (sagittal, coronal, and axial). The filters were set to normal, and only brightness and contrast were adjusted. Images were analyzed on a 27-inch flat-panel display screen with a pixel resolution of 2560 1440 in a dimly lit room without time restrictions. Two external observers (both endodontists) were calibrated and examined the images separately. They were instructed to examine CBCT, DOR, and DPR images and grade their observations using PESS index parameters. The first evaluation was performed on CBCT scans; then, 2 weeks later, either DOR or DPR images were examined. One month later, the evaluation was repeated. The overall kappa index for interobserver and intraobserver agreement was calculated by using a weighted kappa. In case of disagreement, the case was discussed, and a consensus was reached. During their evaluation, observers were looking for teeth that were endodontically treated or had periapical lesions. One COPI score was written for each tooth. The measurement of the lesions was performed in 3 planes (axial, frontal, and sagittal), and the widest distance was registered. If more than 1 root had a lesion, the biggest was considered, and the S component score was determined. For the ETTI part, all canals of the tooth were graded separately, except for the CS for which only 1 score per tooth was assigned. For untreated teeth with periapical radiolucency, only the COPI part of the index was evaluated. If the treatment on the tooth was performed between taking the images, the tooth was excluded.
Statistical Analysis The statistical analysis was performed with SPSS software version 19.0 (SPSS, Inc, Chicago, IL). Significance was set at a P value of .05 or less. All parametric data were expressed as the mean and standard deviation (SD) or the mean and 95% confidence interval. Chi-square tests were used to compare frequencies of qualitative variables. The level of significance was set at P # .05. Agreement between the measurements was evaluated by weighted kappa.
Results In group 1 (mean age = 48.6 [SD = 11.8] years, 31% men and 69% women), a total of 817 teeth (mean = 23.34 [SD = 6.08]), 187 of them endodontically treated (mean = 5.34 [SD = 3.93])
(101 in the upper jaw and 81 in the lower jaw), were analyzed. The distribution of the teeth (66 anterior, 57 premolar, and 64 molar teeth) is equal (by goodness-of-fit test, c22 = 1.08, P = .58). The power of the study is 0.78. In group 2 (mean age = 42.4 [SD = 12.1] years, 65% men and 35% women), a total of 35 endodontically treated teeth (1.75 [SD = 0.91], 27 in the maxilla and 8 in the mandible) were evaluated. The distribution of the teeth (11 anterior, 11 premolar, and 13 molar teeth) was equal (P > .05). The calculated power of the sample was 0.86.
COPI All intra- and interobserver COPI index kappa coefficient scores for all radiologic examination methods were good or very good, except the interobserver agreement scores for CBCT and DPR, which were moderate in the D4 group, and for DOR in the D2, D3, and D4 groups. Table 1 presents an overview of the results of the COPI index. CBCT analysis found more, and larger, lesions (S1 and S2) (P # .05). The relationship between the root and the lesion was more complicated in group 1 (R1–R5) (c25 = 28.36, P < .001) but not significantly different in group 2. In group 1, CBCT imaging was superior in locating lesions in the apical part (D1) (P < .001) and on the side (D2) (P < .001) and in diagnosing cortical bone expansion (D4) (P = .029) and cortical bone destruction (D5) (P < .001). In group 2, CBCT imaging was superior in the diagnosis of a lesion near anatomic landmarks (D3) (P < .05) and cortical bone expansion (D5) (P < .001). ETTI All intra- and interobserver ETTI index kappa coefficient scores for all radiologic examination methods were good or very good, except the interobserver agreement scores, which were moderate for CBCT in the H and CS groups, for DPR in the CS group, and for DOR in the CS, CF1, CF7, and CF9 groups. Table 2 presents an overview of the results of the ETTI index. There were no differences between all methods of investigation regarding the length of the root canal filling, H, and CS. Furthermore, there was no correlation between the quality of the CS and the presence of an endodontic lesion (S1 and S2) (P = .12). Only a few cases of root resorption and surgically treated teeth were registered in group 2 (Table 2). Through CBCT analysis, more root canals (363) were found compared with DOR analysis (303) (P < .001), but no significant
TABLE 1. Results of the Complex Periapical Diagnostic Index of Using Cone-beam Computed Tomographic, Digital Orthopantomography, and Digital Periapical Radiography
Parameter S0 S1 S2 R0 R1 R2 R3 R4 R5 D0 D1 D2 D3 D4 D5
Examination method
Examination method
n = 187 teeth
n = 35 teeth
CBCT
DOR
c2 test and P value
CBCT
DPR
c2 test and P value
77 67 43 77 79 12 3 10 6 77 103 32 11 11 17
126 44 17 126 44 9 3 4 1 126 60 10 6 3 0
c22 = 27.86, P < .001
10 10 15 10 12 2 1 9 1 10 24 15 13 7 12
19 4 12 19 7 3 0 5 1 19 16 10 3 3 0
c22 = 5.70, P = .05
c25 = 28.36, P < .001
P < .001 P < .001 P < .001 P > .05 P = .029 P < .001
c25 = 6.45, P > .05
P < .05 P > .05 P > .05 P < .05 P > .05 P < .001
CBCT, cone-beam computed tomography; COPI, complex periapical index; DOR, digital orthopantomography; DPR, digital periapical radiography.
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Clinical Research TABLE 2. Results of the Endodontically Treated Tooth Diagnostic Index: CBCT, DOR, and DPR Examination method
Examination method Parameter L1 L2 L3 L4 L5 H1 H2 H3 H4 CS1 CS2 CS3 CF1 CF2 CF3 CF4 CF5 CF6 CF7 CF8 CF9
CBCT
DOR
c test and P value
CBCT
DPR
c2 test and P value
197 89 14 46 0 129 101 90 26 38 24 116 4 44 0 0 0 2 82 0 188
175 75 12 27 0 100 87 66 36 52 31 95 2 23 0 0 0 1 71 0 78
c23 = 2.50, df-3, P > .05
49 10 7 2 2 44 14 8 3 16 5 14 2 2 0 1 — — 10 2 42
48 10 5 1 2 42 16 7 1 14 8 11 2 1 1 0 — — 9 2 23
c24 = 0.56, P > .05
2
c23 = 4.94, P > .05
c22 = 5.45, P > .05 P > .05 P = .05 — — — P > .05 P > .05 — P < .001
c23 = 1.18, P > .05
c22 = 1.13, P > .05 P > .05 P > .05 P > .05 P > .05 — — P > .05 P > .05 P < .05
CBCT, cone-beam computed tomography; DOR, digital orthopantomography; DPR, digital periapical radiography.
differences were found in group 2 (CBCT = 74, DPR = 68). In group 1, CBCT imaging found significantly more missed canals (CF2) and more canals associated with lesions (CF9). CBCT imaging enhanced the frequency of diagnosis for some factors (CF1, CF6, and CF7) but without a statistically significant difference. In group 2, because of a low number of teeth, CBCT scanning was only superior in the detection of canals associated with lesions (CF9).
When groups H1 with H2, and H3 with H4 were compared, a post inside the canal did not make any difference (P > .05). A positive correlation was detected between the length of the root canal filling and the presence of an endodontic lesion for all methods of evaluation (P < .05). When analyzing homogeneity of the root canal filling, only CBCT imaging detected a positive correlation with the presence of an endodontic lesion (P = .042). Perforations (CF1), missed canals
Figure 1. The new Complex Periapical Index (COPI) designed for identification and classification of periapical bone lesions in case of apical periodontitis: S, R, and D evaluation scale.
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Clinical Research (CF2), and canal obstruction (CF7) were positively associated with the presence of endodontic lesions (P < .05).
Discussion AP is a disease; its main symptom is bone destruction. AP may be detected with conventional radiography only 15 to 30 days after the development of the disease (18, 19). However, with new technologies like CBCT imaging, it is possible to detect AP as soon as 7 days after it develops (18). AP detection and characterization represent an important preoperative factor that may influence the outcome of root canal treatment; thus, early diagnosis is essential (5, 6, 10). Orstavik et al (2) developed the most popular PAI in which periapical lesions were classified into 5 scores. It is based on a 2-dimensional (2D) radiologic method and cannot be applied to 3-dimensional imaging; furthermore, the original study was done only on upper front teeth and is not based on clinical outcomes, and thus the prognostic value is unknown. Tooth type, number of roots, size and number of lesions, and their location are known to influence treatment prognosis (6, 9–12, 14, 15), but these parameters cannot be assessed using PAI. The other index, called CBCTPAI and developed by Estrela, is based on 3dimensional image interpretation, but only lesion size, plus 2 additional variables of cortical bone expansion and destruction, are analyzed (3); some previously mentioned important parameters are not assessed. There is no such index that implements the all-important aspect of periapical pathosis; moreover, there is a lack of a complex index in which radiologic treatment results can be accessed. It is known from previous studies that length of root canal filling, homogeneity, CS, and existing complications all influence endodontic treatment outcome (4–6, 16, 17), and the parameters proposed by Eckerbom and Magnusson for endodontic treatment evaluation are not complete (4). Most importantly, preoperative, intraoperative, and postoperative parameters included in this study were gathered from previous scientific studies. A pilot study was conducted to evaluate which parameters are possible to evaluate using CBCT imaging, and the results were compared with the control methods (DOR and DPR). The results of the pilot study revealed that the analysis conducted for group 1 and group 2 showed very good overall intraobserver agreement and good interobserver agreement. CBCT image analysis resulted in a higher detection rate for AP than conventional radiography. AP was detected in 32.6%, 45.7%, and 58.8%–71.4% of the teeth by using DOR, DPR, and CBCT imaging, respectively. CBCT imaging also detected larger lesions (S2) than conventional radiography (CBCT = 23%, DOR = 9%, P = .001; CBCT = 43%, DPR = 34%, P = .05). Prevalence of AP might be higher in terms of what could be obtained from 2D radiographic images. Even when lesions are small or are not in an advanced stage, CBCT imaging showed better diagnostic results (20–23). The results obtained in the present study are similar to those from other clinical studies, which suggested that radiologic findings obtained from CBCT imaging may represent the ‘‘true’’ status of the periapical tissues (16, 24). CBCT imaging may also give some false-positive results, but even in a study that used histopathological findings as the ‘‘gold standard,’’ CBCT scans were more sensitive in detecting AP compared with 2D radiography, which was more likely to miss AP when it was still present (25). A limitation of the present study may be that the dynamics of AP cannot be judged. In fact, some of the AP lesions registered might be healing from a previous, bigger, lesion; repeating the analysis in different periods of time may reveal this. If AP is present on several roots in a multirooted tooth, the outcome might be different (11). The present study showed that CBCT imaging revealed a more complicated rootlesion relationship. In group 2, the difference was not significant because of the low number of teeth. Using the conventional indexes, 194
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this information was not analyzed at all. The location and severity of the lesions, such as expansion or destruction of cortical bone, as well as contact with the sinus or the mandibular canal are also more easily missed using conventional radiology (12, 13). The present study revealed similar results; CBCT imaging was superior in detecting lesions in the apical (D1) and lateral areas (D2), expansion (D4) and destruction of cortical bone (D5) in group 1, and diagnosing the contact of the lesion with important anatomic structures (D3) and destruction of cortical bone (D5) in group 2. Analyzing the results of the present study, it was decided to make the COPI index easier and more informative as well as to group each parameter (S, R, and D) into 3 different treatment risks: mild (green color), moderate (yellow color), and high (red color) (Fig. 1). Several studies suggested that lesions more than 5 mm in size may strongly influence prognosis of the treatment (6, 17), so it was decided to include a third score for the S parameter (S3: diameter of large well-defined radiolucency >5 mm) (Fig. 1). For the R evaluation, parameter variations R2, R3, and R4 were joined to only 1 parameter R2 (radiolucent lesion appears on more than 1 root) to better reflect the outcome of multirooted teeth (Fig. 1). For the D evaluation, it was decided to join D1 and D2 into 1 new category, D1 (radiolucency around the root), and to eliminate D4 because intraobserver kappa was moderate (Fig. 1). Each component of the index (S, R, and D) is described independently. D can be described by several components at the same time (eg, COPI S1R1D1 [Fig. 2] or S2R2D1,2 [Fig. 3]). In the present study, the lack of clinical information and scatter and beam hardening caused by high-density neighboring structures and materials were the reasons for the moderate interobserver kappa coefficient for CS and homogeneity through CBCT evaluation. These artifacts did not allow us to fully evaluate the adaptation of the crown and root filling material (26, 27). In the present study, when analyzing canal
Figure 2. An example of the PESS diagnostic index using CBCT imaging of the sagittal plane of the upper cuspid with a radiolucent lesion.
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Clinical Research
Figure 3. An example of the PESS diagnostic index: CBCT imaging of the upper first molar. (A) Frontal plane, palatal root with a radiolucent lesion; (B) frontal plane, distobuccal root; (C) frontal plane mesiobuccal, root and missed mesiobuccal second canal; (D) axial plane, missed mesiobuccal second canal; and (E) sagittal plane, mesiobuccal second canal with radiolucency.
filling length, homogeneity, or CS, all methods of radiologic evaluation registered the same good results without any statistical difference. The presence of a root canal post did not influence the detection of AP, as reported in previously published research (17, 28). Several studies were conducted on the ability of CBCT scanning to detect root canal treatment complications, such as resorptions, perforations, and vertical and horizontal root fractures (29–31). In the present study, the superiority of CBCT imaging to detect missed canals (CF2) and bone lesions (CF9) has been confirmed, even if no
cases of resorption (CF3–CF5) and few cases of root canal perforations (CF1), root fractures (CF6), and roots that underwent endodontic surgery (CF8) were registered (Table 2). Upon analyzing the results of the present study, it was decided to also make the ETTI index easier and to select its final parameters. Because the presence of a post inside the canal did not make any difference, grades H3 and H4 were removed from the final index (Table 3). The CS3 (undetermined) parameter was removed in the final index because there were no clinical data available, which is essential
TABLE 3. The New Endodontically Treated Tooth Index: L, H, CS, and CF Evaluation Scale L (length of the root canal filling) L1 0–2 mm from radiographic apex L2 >2 mm from radiographic apex L3 Overfilling (extrusion of material through the apex) L4 Filling material visible only in pulp chamber L5 Filled canal of a surgically treated root. H (homogeneity of the root canal fillings) H1 Complete obturation (homogenous appearance of the root canal filling) H2 Incomplete obturation (voids and porous appearance of the root canal filling) CS (coronal seal) CS1 Adequate (coronal restoration appears intact radiographically) CS2 Inadequate (detectable radiographic signs of overhangs, open margins, recurrent caries, or lost coronal restoration) CF (complications/failures) CF0 No complications CF3 Root resorption CF1 Root perforation CF4 Root/tooth fracture CF2 Root canal not treated/missed CF5 Endodontically treated root with radiolucency
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Clinical Research for judging CS. For the complication/failure parameters, it was decided to join all resorption parameters (CF3, CF4, and CF5) into 1 final parameter, CF3 (root resorption), and remove CF7 (canal obstruction) and CF8 (surgically treated root with bone radiolucency) because it is possible to get this data from the other parameter grades (Table 3). Each component of ETTI is described independently. For example, ETTI of a 1-rooted tooth is expressed as L1H1CS2CF5 (Fig. 2), whereas the ETTI of a multirooted tooth (ie, the palatal canal) is expressed as L1H1CS2CF5 (Fig. 3). CF can also be described by several parameters at the same time (ie, L2H2CS2CF1,5 and L1H1CS1CF4,5). The newly developed PESS index described in the present study is complex and different from all other indexes already present in the literature. It allows the evaluation of not only the status of periapical tissues but also endodontic treatment quality. Furthermore, the COPI periapical index has prognostic value because of its suggested AP treatment risk degrees. PESS can be used in epidemiological studies and clinical practice. Future research must validate it in large multicenter clinical studies, with a higher number of examiners and patients. Patients should be followed up for at least 2 years to validate the significance of parameter variations. Finally, if universally adopted, this system of evaluation might allow groups worldwide to calibrate and build powerful combined data.
Conclusion The classification proposed in the present study for the evaluation of periapical status and endodontic treatment quality seems to be reproducible and objective and adds helpful information to the existing indexes. Future studies need to be conducted to validate PESS.
Acknowledgments The authors deny any conflicts of interest related to this study.
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