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Accuracy of three dimensional imaging in assessing maxillary molar furcation involvement


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  • 1. J Clin Periodontol 2010; 37: 436–441 doi: 10.1111/j.1600-051X.2010.01556.xAccuracy of three-dimensional Clemens Walter, Roland Weiger and Nicola U. Zitzmann Department of Periodontology,imaging in assessing maxillary Endodontology and Cariology, University of Basel, Basel, Switzerlandmolar furcation involvementWalter C, Weiger R, Zitzmann NU. Accuracy of three-dimensional imaging inassessing maxillary molar furcation involvement. J Clin Periodontol 2010; 37:436–441. doi: 10.1111/j.1600-051X.2010.01556.x.AbstractAim: To assess the accuracy of cone beam computed tomography (CBCT) indetecting furcation involvement (FI) in maxillary molars.Material and Methods: Fourteen patients with generalized advanced chronicperiodontitis were consecutively recruited and treated non-surgically. In maxillarymolars considered for furcation surgery due to increased FI and/or increased probingpocket depths during re-evaluation, CBCT was performed and the degree of FI wasevaluated from the CBCT images. Furcation surgery was performed in 25 maxillarymolars. Intra-surgical FI assessments were compared with data derived from CBCTimages.Results: Overall, 84% of the CBCT data were confirmed by the intra-surgical findings(weighted k 5 0.926, 95% confidence interval: 0.681–1.0). While 14.7% (11 sites)were underestimated (CBCT less than intra-surgical value), in only 1.3% (one site) didthe CBCT data lead to an overestimation compared with the intra-surgical analysis. Key words: cone beam computedThe agreement between both assessments was the highest in distopalatal furcation tomography; 3D imaging; furcationentrances, followed by buccal and mesiopalatal. involvement; maxillary furcation surgeryConclusions: CBCT images demonstrate a high accuracy in assessing the loss ofperiodontal tissue and classifying the degree of FI in maxillary molars. Accepted for publication 30 January 2010Conventional clinical diagnoses of the surgery. Any discrepancies between pre- roots, have also been found to be relevantfurcation involvement (FI) of maxillary and intra-surgical findings may lead to for the decision-making process aboutmolars using a curved periodontal probe an alteration of the surgical treatment whether to surgically treat a suspectedand two-dimensional (2D) radiographic ¨ plan (Muller & Eger 1999). maxillary molar. Discrepancies betweenimaging do not, in many instances, Three-dimensional diagnostic app- conventional and CBCT-based treatmentprovide sufficient information about roaches, including cone beam computed approaches were found in the majority ofthe molars’ periodontal tissue support tomography (CBCT) with reduced radia- the teeth (Walter et al. 2009). Given theand the inter-radicular bone (Hempton tion exposure, have been introduced potential of 3D imaging for the diagnosis ¨& Leone 1997, Muller & Eger 1999, Al- recently in periodontology (Misch et al. and treatment planning of FI maxillaryShammari et al. 2001). Detailed infor- 2006, Mol & Balasundaram 2008, Barri- molars, these radiographic data should bemation about the furcation morphology viera et al. 2009, Grimard et al. 2009, validated with intra-surgical, however, required for molar teeth Liang et al. 2009). CBCT has been The aim of this study was to comparebefore they are subjected to periodontal applied in vivo for the assessment of the intra-surgical assessment of FI of furcation invasion and treatment planning maxillary molars with data generated by in maxillary molars (Walter et al. 2009). CBCT.Conflict of interest and source of Almost half of the assessments based onfunding statement clinical measures and periapical radio-The authors declare that they have no graphs revealed an underestimation ofconflict of interests. the FI when compared with the CBCT Material and MethodsSource of funding: The study was self- analysis. Several additional radiographic The study group comprised 14 patients,funded by the authors and their institution. findings, such as fusion or proximity of five women and nine men, with a mean436 r 2010 John Wiley & Sons A/S
  • 2. Accuracy of 3D imaging 437age of 57.0 years (range 42–81 years) use. Tooth extractions, provisional assessments in part of the current studyand a diagnosis of generalized chronic restorations, splinting of teeth and endo- population was published in Walterperiodontitis. A total of 14 first and 11 dontic (re-) treatment were conducted if et al. (2009). Patients with at leastsecond maxillary molars with 75 furca- indicated. Non-surgical periodontal one maxillary molar with persistingtion entrances were included (Table 1). treatment, i.e. scaling and root planing increased PPD (X6 mm) and advancedPatients were consecutively recruited with hand instruments and ultrasonic FI, defined as horizontal inter-radicularduring September 2006 and October devices, was performed at least 6 loss of periodontal tissues of degree 2 or2009 from the pool of patients at the months before inclusion in the study 3 (Hamp et al. 1975), were consideredDepartment of Periodontology, Endo- on all teeth with periodontal probing for possible inclusion in the currentdontology and Cariology, University of depths of X4 mm. Local anaesthesia investigation.Basel, Switzerland. The study was was administered if indicated. Allapproved by the Ethics Research Com- patients were included in a supportive Analyses of dental CBCTmittee of the University of Basel, Swit- periodontal treatment programme at 3–zerland (EK: 279/09). Patients were 4-month intervals. Re-evaluations of the CBCT were performed in the posteriorthoroughly informed about the rationale periodontal conditions were regularly maxillary area using the high-resolutionfor the study and the methods applied performed and revealed ‘‘closed perio- imaging system 3D Accuitomo 60, XYZand gave their informed consent. ¨ dontal pockets’’ ( Wennstrom et al. Slice View Tomograph (J. Morita, The detailed clinical and radiographic 2005), i.e. with probing pocket depths Kyoto, Japan). Cylindrical volumes ofperiodontal examinations are described (PPD) of 44 mm and no bleeding on 4 Â 4–6 Â 6 cm, settings in the range ofin Walter et al. (2009). In brief, com- probing of most of the periodontia 74–90 kV, 5–8 mA and voxel sizes inplete clinical and radiographic examina- involved. Periodontal surgery was con- the range of 0.08–0.25 mm (2 lp/mm)tions were performed by two trained sidered for sites with PPDX6 mm or were used depending on the region ofperiodontists (N. U. Z. and C. W.), increased FI. Individuals subjected to interest. CBCT was performed 3–6whose measurements were calibrated periodontal surgery in the maxillary months before surgery. The CBCT(Cohen’s k 5 0.619). Instructions for molar area were further evaluated using images of each tooth included weresupragingival plaque control were given CBCT. A comparison of the data from analysed in the horizontal, sagittal andand, if necessary, for stopping tobacco CBCT analysis and non-surgical FI transversal sections by two of the authors (C. W. and N. U. Z.). All images were analysed on the same monitorTable 1. Data about furcation involvement (FI) obtained from CBCT analyses, performed (48 cm, 191, Viewmedic 19C, Totoku,treatments and FI obtained from intra-surgical findings Japan) under standard conditions. TheSubject no. Tooth region PPD (mb-mp) FI CBCT (b, mp, dp) Periodontal surgery software i-Dixel-3DX (J. Morita), with a linear measurement tool and a digital Treatmentn FI (b, mp, dp) magnification lens, was used. It facil-1 26 3/3/3/8/5/6 III/III/III 5 III/III/III itates a continuous motion with the 16 2/3/4/6/6/6 III/III/III 1b III/III/III cursor in the 3D area visualized in the 17 5/4/5/6/2/7 III/III/III 1b III/III/III three planes on the computer screen2 27 4/5/8/8/2/7 III/III/III 1b III/III/III (Fig. 1).3 16 3/2/3/5/2/2 III/III/III 5 III/III/III FI was calculated in the horizontal4 26 2/3/9/8/2/3 III/0/III 3a III/0/III plane by measuring the distance 27 6/2/4/8/4/5 0/I/II 1a 0/I/II between the outer root surface and the5 26 4/3/5/6/2/3 I/0/I 1a I/I/I inter-radicular bone to the nearest milli- 27 5/3/6/6/3/5 0/0/0 1a I/I/I6 27 2/2/3/3/2/3 III/III/III 1b III/III/III metre. The degree of FI was graded7 26 3/2/6/5/2/8 0/III/III 3b I/III/III according to Hamp et al.’s (1975) clas- 27 5/2/8/8/3/5 0/III/III 3b I/III/III sification system. 16 2/2/7/8/2/3 0/0/II 1a I/I/II 17 3/2/4/4/2/4 0/0/0 1a I/I/I Degree 0: no horizontal loss of perio-8 16 4/5/9/7/6/5 III/III/III 5 III/III/III dontal tissue support, i.e. no radiolu- 17 7/3/6/8/3/9 III/III/III 1b III/III/III cency in the furcation area.9 16 3/3/5/6/5/8 III/III/III 1b III/III/III10 26 4/6/9/5/9/8 III/III/III 5 III/III/III Degree I: horizontal loss of perio- 27 3/2/4/7/6/3 I/I/I 1a I/I/I dontal tissue support up to 3 mm.11 26 3/2/9/9/2/3 0/I/II 3a 0/I/II Degree II: horizontal loss of support12 16 3/2/2/3/3/4 III/III/III 3a III/III/III exceeding 3 mm, but no ‘‘through and13 26 3/2/3/4/3/9 III/III/III 1b III/III/III through’’ destruction. 27 4/5/4/6/3/3 III/III/III 1b III/I/III Degree III: horizontal ‘‘through and14 16 3/2/3/3/8/4 I/II/I 3b I/II/I through’’ – destruction of the perio- 17 3/2/3/8/7/3 0/0/II 1a 0/0/II dontal tissue in the furcation.n Treatment according to invasiveness: 1. open flap debridement with apically repositioned flap(ARF), without (a)/with tunnelling (b); 2. root separation; 3. (a–c) amputation/trisection of thedistobuccal, palatal or mesiobuccal root (with or without root separation or tunnel preparation); Intra-surgical examination of FI4. (a–c) trisection and removal of two roots (palatal and the distobuccal, distobuccal and themesiobuccal, mesiobuccal and the palatal root); 5. extraction of the entire tooth. CBCT, cone beam When resective therapy was plannedcomputed tomography; PPD, probing pocket depth. and/or periapical lesions were presentr 2010 John Wiley & Sons A/S
  • 3. 438 Walter et al. scheduled for supportive periodontal treatment at 3–4-month intervals. The treated molars were restored with fixed dental prosthesis, if indicated. Comparison of intra-surgical and CBCT- based assessments The degree of FI recorded during perio- dontal surgery was compared with the degree estimated previously from CBCT imaging. The CBCT diagnosis was either confirmed or a radiographic over- or underestimation was revealed according to the intra-surgical data. Statistical analysis The null hypothesis was that no differ- ence exists between the CBCT-based estimation and the following intra-sur- gical assessment. The rate of agreement was analysed using Cohen’s k and weighted k with 95% confidence inter- vals (CI) and an approximate standard error (Cohen 1960, Fleiss et al. 1969). Weighted k were used in order to assign different weights to subjects where the assessments differed by categories (FI), which meant that the amount of dis-Fig. 1. Cone beam computed tomography with horizontal, sagittal and transversal sections of agreement could be taken into account.the first and the second left maxillary molars (subject no. 4). For explorative statistics, cross tables and mosaic plots were created. All cal- culations were performed using the sta-in the respective maxillary molar, root Furcation surgery was performed tistical package R (the R Foundation forcanal treatment was performed before according to a recently introduced clas- Statistical Computing Version 2.9.2,the surgical intervention. The CBCT- sification of invasiveness (Table 1 and Vienna, Austria).generated data were available to the Fig. 2; Walter et al. 2009):surgeon before the periodontal surgery.During surgery, patients first rinsed with 1. open flap debridement with an api-chlorhexidine (0.2%), and then local Results cally repositioned flap (ARF), with-anaesthesia was administered labially out (a)/with tunnelling (b); The measurements of PPD obtainedand palatally, and paramarginal or sul- 2. root separation; during re-evaluation are presented incular incisions were performed, depend- 3. (a–c) amputation/trisection of the Table 1, as are the FIs from the CBCTing on the amount of keratinized tissue distobuccal, palatal or mesiobuccal analyses and FI recorded during surgery.present. The surgical area affected all root (with or without root separation The analysis from CBCT revealed an FIteeth with PPDX6 mm of a maxillary or tunnel preparation); in 59 out of 75 furcation entrances.quadrant. A distal wedge was prepared 4. (a–c) trisection and removal of two While an FI degree I was assessed inif indicated. Vertical releasing incisions roots (palatal and the distobuccal, nine and degree II in five entrances, thewere made palatally and labially. After distobuccal and the mesiobuccal, majority of sites (45) revealed a throughthorough debridement using hand mesiobuccal and the palatal root); and through involvement (degree III).instruments and ultrasonics, the furca- 5. extraction of the entire tooth. The furcation surgery comprised antion defects were visualized and evalu- open flap debridement with ARF in 15ated by a trained periodontist (C. W. or The wound was sutured using 5 Â 0 molars (seven without, eight with tun-N. U. Z.) and the assisting dentist, who or 6 Â 0 monofil polyethylene sutures nelling). Root amputation was per-was blind to the CBCT data. FI was (Prolene, Ethicon, Johnson and Johnson, formed on six teeth (three timesclassified at three sites (buccal, mesio- Somerville, NJ, USA). Patients were distobuccal and three times palatal rootpalatal and distopalatal) of the suspected advised to rinse twice a day with chlor- resection), and four teeth were extractedmaxillary molars according to measure- hexidine (0.2%). Sutures were removed after intra-surgical analyses. Thesements with a curved scaled Nabers 6 or 7 days post-surgery. Patients were intra-surgical measurements showedprobe (PQ2N, HU-Friedy, Chicago, IL, shown how to apply fluorid and chlor- that the furcation was not involvedUSA), marked at 3 mm intervals (Hamp hexidine gel in the furcation area and/or (degree 0) in five entrances, FI degreeet al. 1975). between the (remaining) roots, and I was found in 21, FI degree II in five r 2010 John Wiley & Sons A/S
  • 4. Accuracy of 3D imaging 439and FI degree III in 44 entrances. All ‘‘overestimation’’ were based on the FIointra-surgical FI). Hence, for themolars had an FI degree I–III in at least assumption that the method with higher comparison of clinical FI data withtwo of the three entrances, in both the accuracy serves as a reference (accuracy CBCT data in Walter et al. (2009), theCBCT and the intra-surgical analysis. of FI diagnosis: clinical FIoCBCT estimation of FI in CBCT was supposedComparison of FI in CBCT and intra-surgical assessmentOverall, 84% of the CBCT data wereconfirmed by the intra-surgical findings,with a weighted k 5 0.926 (95% CI:0.681–1.0). This indicates a high degreeof accuracy and verifies the null hypoth-esis (Fig. 3a). According to the six-levelnomenclature (Landis & Koch 1977), kvalues between 0.81 and 0.92 are con-sidered as an almost perfect agreement.Among the sites that did not reveal an FIin the CBCT, five were verified as FIdegree 0 following debridement, while11 showed indeed an FI degree I intra-surgically. All entrances with FI degreeI or II in CBCT were verified intra-surgically. Among the sites with FI Fig. 2. Intra-surgical clinical photographs of the left maxillary molars of subject no. 4. (a)degree III, all except one were indeed Pre-surgical view, (b) tri-section of the distobuccal root in the first maxillary molar, (c) the flap is fixed with monofil synthetic sutures 5 Â 0, (d) 4 months p.o., the wound healing wasthrough and through furcations. Thus, uneventful, (e) a crown with an extended metal margin is placed and the patient is instructedwhile 14.7% (11 sites) were underesti- in meticulous oral hygiene.mated (CBCT less than intra-surgicalvalue), only 1.3% (one site) revealed FI surgery FI surgeryan overestimation in the CBCT as com-pared with the intra-surgical analysis. 0 1 23 0 1 23 A separate analysis of the three furca- 0 0tion locations showed that there seemedto be the greatest degree of agreement 1 FI CBCT FI CBCT 2 1between CBCT and intra-surgical mea- 2surements for the distal (k 5 0.95, 95%CI:0.603–1.0) and buccal (k 5 0.94, 3 395% CI:0.465–1.0) entrances, whilethe agreement for the mesial measure-ments amounted to k 5 0.89 (95% CI: a b0.449–1.0) (Fig. 2b–d). The lower valuefor the mesial entrances was caused bythe underestimation (CBCT less thanintra-surgical) in four entrances, which FI surgery FI surgerywere assessed as FI degree 0 in CBCT, 0 1 23 0 1 23and one overestimation as FI degree III 0in the CBCT, which was shown to be an 0 1FI degree I intra-surgically. 1 2 FI CBCT FI CBCT 2Discussion 3 3The present study has demonstrated thatestimates from a 3D CBCT of the FI ofmaxillary molars have a high degree ofagreement with those from intra-surgi- c dcal assessments. While data derived from CBCTproved to be very accurate in maxillary Fig. 3. Degree of furcation involvement (FI, n 5 75) obtained by cone beam computedmolars with FI, discrepancies exist tomography imaging compared with intra-surgical findings. The level of agreement betweenbetween the pre-surgical clinical assess- both assessments was calculated by means of Cohen’s unweighted and weighted k statisticments and the CBCT. The definitions (approximate standard error, 95% CI) for: (a) all FI, (b) buccal FI, (c) mesiopalatal FI and (d)of the terms ‘‘underestimation’’ and distopalatal FI.r 2010 John Wiley & Sons A/S
  • 5. 440 Walter et be more accurate. In contrast, in the conventional radiological imaging tech- of high-risk organs in the skull, such aspresent investigation analysing CBCT- niques. the eye lens and thyroid gland. One ofgenerated data in comparison with intra- Little work has been carried out to the advantages of the CBCT is that itsurgical assessments, the latter was assess the advantages of 3D computed requires less radiation exposure with asupposed to be the ‘‘gold standard’’ and tomographies for periodontal diagnosis. smaller volume that can be restricted totaken as a reference. The CBCT data Vandenberghe et al. (2008) compared examine only the area of interest. How-were compared with this gold standard the detection of periapical radiographs ever, the fundamental principle for diag-and were therefore either confirmed or and CBCT with the intra-oral situation nostic radiology abbreviated ALARArated as over- or underestimated. following flap surgery in two human (as low as reasonably achievable) has According to Walter et al. (2009), the skulls containing multiple periodontal to be followed, and additional CBCTestimated degree of FI based on clinical defects (FIs and intra-bony defects). On procedures should be reserved for spe-findings was confirmed in the CBCT in the periapical radiographs, the detection cial cases (Farmann 2005). No matteronly 27% of the sites, while 29% were of FI failed in 44% of the cases, and only how low the dose, it is excessive if it isoverestimated and 44% revealed an 20% of the FIs were correctly classified. unlikely to improve the outcomes of theunderestimation according to CBCT In contrast, 100% detectability and cor- treatment provided. The study describedanalyses. The overall agreement was rect classification were observed with in this paper shows that the FI in max-‘‘moderate,’’ with a Cohen’s weighted CBCT. Misch et al. (2006) obtained illary molars can be classified withk 5 0.518 (95% CI:0.269–0.767). similar results, with 100% detection of CBCT to a high degree of accuracy.Among degree I FI, 25% were under- the artificially created intra-bony defects According to Walter et al. (2009),estimated, among degree II and II–III with CBCT and only 67% on periapi- CBCT facilitates a more detailed surgi-(i.e. X6 mm, but not ‘‘through and cals. Fuhrmann et al. (1997) found that cal treatment planning with a clearthrough’’), the underestimation was as only 21% of the artificial FIs were decision about resective interventionshigh as 75%, while all sites with degree identified on periapicals and 100% in the maxillary molar region. In con-III FI were confirmed in the CBCT. The through high-resolution CT. Mengel trast, clinical data and periapical radio-largest discrepancies were observed in et al. (2005) compared the periapical graphs led to two or even more differentdistal furcation entrances (k 5 0.319, radiographs, panoramics, CT and CBCT treatment options. Ideally, complete95% CI: À 0.059–0.697), while the measurements of different experimental preoperative endodontic treatment isagreement in buccal entrances was periodontal defects (furcations, dehis- performed only in those roots that arek 5 0.584 (95% CI:0.135–1.0) and cences, fenestrations) with their corre- intended to be retained. Avoiding unne-k 5 0.528 (95% CI:0.085–0.971) in sponding histologic specimens. Intra-oral cessary treatment interventions gener-mesial sites. It was further demonstrated radiography was limited by visibility in ally enables a reduction in patientthat CBCT can provide substantial addi- the buccolingual direction, while image discomfort, treatment time and costs,tional information about the root mor- quality (such as contrast, brightness, and thus probably leads to greater treat-phology and the residual attachment of distortion and clarity of bone structures) ment effectiveness. Based on the find-maxillary molar teeth (Walter et al. was superior using CBCT. In the present ings of this study, CBCT imaging in the2009). in vivo investigation, the assessment posterior maxillary area has some clear Clinical and conventional radio- from CBCT was correct in 84% of all benefits. However, neither long-termgraphic measures have been shown to maxillary furcations. An underestima- data on CBCT-‘‘guided’’ maxillaryhave limitations in several studies when tion was observed in 14%, all of which molar surgery nor data from a cost–compared with intra-surgical assess- were actually FI degree I, while no benefit analysis are available for thisments as the ‘‘gold standard’’. In these involvement was found in the CBCT. new vitro and in vivo studies, under- These discrepancies may be explained Thus, the indication for additionalestimations of more severely defect by the surgical protocol probably lead- CBCT imaging should be based notmorphologies, such as FI degree II and ing to a minor loss of periodontal tissues just on the clinical situation, e.g. aIII, are common irrespective of the during instrumentation involving suspected trifurcation, which is hard toradiographic measure applied. Eickholz Gracey curettes and ultrasonic devices. detect and interpret, but also on selec-and Hausmann (2000) investigated the For clarification, FI degree I is defined tion criteria derived from the overallinter-proximal bone loss from pre-surgi- as ‘‘furcation entrance – just detectable periodontal and reconstructive treatmentcal periapical radiographs and found with horizontal loss of periodontal tis- plan. Such criteria could be the need forthat the defects were on average sues up to 3 mm’’. An overestimation in retention of posterior abutment tooth1.4 mm deeper intra-surgically. Topoll the CBCT was a rare finding in this with good prognosis, and patient’s den-et al. (1988) compared the clinical and sample. In one of the second maxillary tal and/or medical history and compli-radiological findings of involved furca- molars, an expected ‘‘through and ance. Moreover patient’s desires andtions with the morphological situation through’’ – destruction of the perio- requests are also relevant, e.g. if theyduring surgical treatment. With periapi- dontal tissue in the furcation was not favour tooth retention and want to avoidcal radiographs, the degree of FI was confirmed intra-surgically. The discre- implant placement with maxillary sinuscorrectly identified and classified in pancies between both measurements surgery. The technical and financial44% of all investigated molars, with were most likely related to an over- effort involved and the additional radia-panoramic radiographs in 40%, and estimation of the degree of deminerali- tion risk of the CBCT examination canwith clinical probing alone in 54%. zation in the furcation area in the be justified in patients for whom clinicalThus, simple clinical probing appears radiographic image. measures and conventional radiographsto be more accurate in assessing the The drawback of all radiological cannot provide sufficient information.involved furcations than either of the techniques is the exposure to radiation CBCT could also be used for more r 2010 John Wiley & Sons A/S
  • 6. Accuracy of 3D imaging 441complex periodontal treatment planning, method to assess and measure palatal masti- Mengel, R., Candir, M., Shiratori, K. & Flores-such as resective furcation surgery, catory mucosa by cone-beam computerized de-Jacoby, L. (2005) Digital volume tomo-which also involves prior endodontic tomography. Journal of Clinical Perio- graphy in the diagnosis of periodontaland consecutive restorative treatment. dontology 36, 564–568. defects: an in vitro study on native pig and Cohen, J. (1960) A coefficient of agreement for human mandibles. Journal of Periodontology nominal scales. Educational and Psychologi- 76, 665–673. cal Measurement 20, 37–46. Misch, K. A., Yi, E. S. & Sarment, D. P. (2006)Conclusions Eickholz, P. & Hausmann, E. (2000) Accuracy Accuracy of cone beam computed tomogra-In the present study, CBCT and intra- of radiographic assessment of interproximal phy for periodontal defect measurements.surgical assessments of maxillary molar bone loss in intrabony defects using linear Journal of Periodontology 77, 1261–1266. measurements. European Journal of Oral Mol, A. & Balasundaram, A. (2008) In vitroFI were found to be in substantial agree- Sciences 108, 70–73. cone beam computed tomography imaging ofment. CBCT enables an exact estima- periodontal bone. Dentomaxillofacial Radiol-tion and classification of the FI, as well Farmann, A. G. (2005) ALARA still applies. Oral Surgery Oral Medicine Oral Pathology ogy 37, 319– a visualization of the root morpholo- ¨ Muller, H. P. & Eger (1999) Furcation diag- Oral Radiology Endodontics 100, 395–397.gies with root proximities or root Fleiss, J. L., Cohen, J. & Everitt, B. S. (1969) nosis. Journal of Clinical Periodontology 26,fusions. These measures are essential Large sample standard errors of kappa and 485–498.for a reliable diagnosis and prognosis weighted kappa. Psychological Bulletin 72, Topoll, H. H., Streletz, E., Hucke, H. P. &of the maxillary molar and for adequate Lange, D. E. (1988) [Furcation diagnosis– 332–327.treatment planning, particularly when comparison of orthopantomography, full Fuhrmann, R. A., Bucker, A. & Diedrich, P. R. mouth X-ray series, and intraoperative find-the tooth or remaining roots are in (1997) Furcation involvement: comparison of ¨rztliche ing] (in German). Deutsche Zahnaneed of restorative treatment. dental radiographs and HR-CT-slices in Zeitschrift 43, 705–708. human specimens. Journal of Periodontal Vandenberghe, B., Jacobs, R. & Yang, J. (2008) Research 32, 409–418. Detection of periodontal bone loss using Grimard, B. A., Hoidal, M. J., Mills, M. P.,Acknowledgements digital intraoral and cone beam computed Mellonig, J.T, Nummikoski, P. V. & Mealey, tomography images: an in vitro assessmentThe authors would like to thank the B. L. (2009) Comparison of clinical, periapi- of bony and/or infrabony defects. Dentomax-members of the Department of Perio- cal radiograph, and cone-beam volume tomo- illofac Radiol 37, 252–260.dontology, Endodontology and Cariol- graphy measurement techniques for assessing Walter, C., Kaner, D., Berndt, D. C., Weiger, R.ogy for their help in the current bone level changes following regenerative & Zitzmann, N. U. (2009) Three-dimensionalinvestigation and Dr. Leonard Buttel ¨ periodontal therapy. Journal of Perio- imaging as a pre-operative tool in decisionfor performing the reconstructive ther- dontology 80, 48–55. making for furcation surgery. Journal ofapy of the case presented in Fig. 2. The Hamp, S. E., Nyman, S. & Lindhe, J. (1975) Clinical Periodontology 36, 250–257. Periodontal treatment of multirooted teeth. ¨ Wennstro m, J. L., Tomasi, C., Bertelle, A. &technical assistance of Dr. Dorothea Results after 5 years. Journal of Clinical Dellasega, E. (2005) Full-mouth ultraso-Berndt in performing the CBCT ima- Periodontology 2, 126–135. nic debridement versus quadrant scalingging is highly appreciated. The authors Hempton, T. & Leone, C. (1997) A review of and root planing as an initial approach inalso gratefully acknowledge the help of root resective therapy as a treatment option the treatment of chronic periodontitis. ¨Andy Schotzau and Urs Simmen with for maxillary molars. J Am Dent Assoc 128, Journal of Clinical Periodontology 32, 851–the statistical analysis. 449–455. 859. Landis, J. R. & Koch, G. G. (1977) An applica- tion of hierarchical kappa-type statistics in the assessment among multiple observers. Address: Biometrics 33, 363–374. Nicola U. ZitzmannReferences Liang, X., Jacobs, R., Martens, W., Hu, Y., Department of Periodontology, EndodontologyAl-Shammari, K. F., Kazor, C. E. & Wang, H. Adriaensens, P., Quirynen, M. & Lambrichts, and Cariology L. (2001) Molar root anatomy and manage- I. (2009) Macro- and micro-anatomical, his- University of Basel ment of furcation defects. Journal of Clinical tological and computed tomography scan Hebelstrasse 3 Periodontology 28, 730–740. characterization of the nasopalatine canal. 4056 Basel ´Barriviera, M., Duarte, W. R., Januario, A. L., Journal of Clinical Periodontology 36, 598– Switzerland Faber, J. & Bezerra, A. C. (2009) A new 603. E-mail: Clinical Relevance Principal findings: Assessments of pre-operative decision making. In Scientific rationale for study: Diffi- the FI of maxillary molars with den- selected cases, CBCT should be culty exists in clinically diagnosing tal CBCT were found to agree well used as an additional diagnostic tool FI in maxillary molars and selecting with the intra-surgical findings. in the maxillary posterior region. the appropriate treatment modality. Practical implications: Using 3D imaging provides relevant data forr 2010 John Wiley & Sons A/S