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Int Poster J Dent Oral Med 3 (2001), No. 1     15. Mar. 2001

Int Poster J Dent Oral Med 2001, Vol 3 No 1, Poster 61

Reliability of assessing interproximal bone loss

Language: English

Author(s): Eric von Bethlenfalvy, Britta Wolf, Stefan Haßfeld, Hans Jörg Staehle, Peter Eickholz
Dept. of Operative Dentistry & Periodontology, Dept. of Maxillofacial Surgery, University of Heidelberg, Germany

Date/Event/Venue: 
24.08.2000-27.08.2000
The 4th Joint Meeting of the IADR CED/NOF
Warsaw, Poland

Introduction

Objective
The aim of this study was to assess the reliability of linear measurements of interproximal bone loss on digitized radiographic images after the use of different filters.

Material and Methods

Material and Methods I
Patients

  • 50 patients (29 female) 22-65 years of age.
  • untreated advanced periodontal disease.
  • each exhibiting one interproximal intrabony defect.

Radiographic examinations

  • standardized bitewing radio-graphs of teeth with intrabony defects using modified film holders (VIP 2 Film Positioning, UpRad Corp., Fort Lauderdale, FL, USA) (Fig. 1, 2). Two orthodontic wires were placed on the mandibular side of the filmholder at a specified position. Shadows of these wires were cast onto the radiographs (Fig. 1). From the distances between the images of these wires on a radiograph, the vertical and horizontal angulation difference between the central beam and the orthoradial projection could be calculated.
  • intraoral dental films (Ultraspeed, Eastman Kodak Co., Rochester, NY, USA) size 2.
  • x-ray source (Heliodent 70, 70 kV, 7 mA, Siemens, Bensheim, Germany).
  • development unit (Periomat, Dürr Dental GmbH, Bietigheim-Bissingen, Germany).

Material and Methods II
Clinical examinations
At 6 sites per tooth:

  • Gingival Index (GI) and Plaque Index (PlI).
  • PD and PAL-V to the nearest 0.5 mm (PCPUNC 15).

After reflection of a full thickness flap:

  • distance cemento-enamel junction (CEJ) to the most apical extension of the bony defect (BD).
  • the height of the 3-wall as well as the 2- and 3-wall component of each interproximal lesion.
  • all clinical measurements were performed by one examiner (PE) to the nearest 0.5 mm (PCPUNC 15).

Radiographic evaluation
Measurements using a loupe of 10 fold magnification and a 0.1 mm grid (Scale loupe 10, Peak,Tohkai Sangyo, Tokyo, Japan):

  • distances between the projections of the orthodontic wires that had been fixed to the filmholders vertically (dv) and horizontally (dh) on every radiograph (Fig. 1).
  • capturing of each radiograph with a flat bed scanner (Linotype Saphir, Friadent, Mannheim, Germany) with 600x1200 dpi resolution.
  • all radiographs were analysed (CEJ-AC/ -BD) by 2 examiners blinded to the clinical and intrasurgical measurements: EvB, BW (Fig. 1).
  • enlargement:  7x, 14x
  • the length of the cast shadow of the wire placed on the maxillary side of the filmholder was marked (Fig. 1) and the length of the wire was entered into the program (Friacom, Friadent). All further measurements were adjusted according to the enlargement of each individual radiograph automatically.

Statistical analysis

  • Kolmogorov-Smirnov/Lilliefors-Test for normal distribution.
  • comparison of intrasurgical / radiographic measurements by paired t test.
  • stepwise multiple linear regression analysis:
  • dependent variable:  intrasurgical / radio-graphic measurements
  • explanatory variables: patient, angulation differences, analysing method, intrasurgical parameters

Results

Results I

  • For the distance CEJ-AC the dentist had a lower measurement variability than the final year dental student (Tab. 2).
  • For the distance CEJ-BD filters had significant influence on reproducibility in correlation with vertical angulation difference (Tab. 3).
  • For the distance CEJ-AC "structure" resulted in less valid measurements than the other imaging modes (Tab. 5).

Results II

 

clinical parameters

angulation difference/°

 

GI

PlI

PPD/mm

PAL/mm

vertical

horizontal

mean ± SD

1.88 ± 0.44

0.32 ± 0.68

7.96 ± 1.73

8.82 ± 1.78

1.79 ± 1.41

0.99 ± 1.25

range

0.0 - 2.0

0.0 - 2.0

4.0 - 12.0

5.0 - 13.0

0.0 - 6.3

0.0 - 6.6

Table 1: Clinical parameters of 50 interproximal lesions and vertical as well as horizontal angulation difference of the central beam from the orthoradial projection of 50 radiographs (mean ± standard deviation [SD]; range [minimum - maximum]; Gingiva Index: GI; Plaque Index: PlI; probing depth: PPD; attachment level: PAL).

 

source

SSQ

DF

MSQ

F-ratio

P

G-G

H-F

between subjects

examiner

6.85

1

6.85

6.83

0.010

 

 

height of 2wall component

4.00

1

4.00

4.00

0.047

 

 

error

197.57

197

1.00

       

within subjects

filter

4.03

2

2.02

2.67

0.071

0.090

0.089

filter x examiner

1.06

2

0.53

0.70

0.497

0.450

0.452

filter x height of 2wall comp.

8.68

2

4.24

5.74

0.003

0.009

0.009

error

297.95

394

0.76

       
Table 2: Repeated measures analysis of variance: reproducibility of radiographic measurements;
dependent variable: amount of the difference first minus second radiographic measurement (CEJ-AC)

 

source

SSQ

DF

MSQ

F-ratio

P

G-G

H-F

between subjects

vertical angulation

0.21

1

0.28

0.19

0.664

   

error

218.57

198

1.10

       

within subjects

filter

0.19

2

0.10

0.16

0.853

0.832

0.835

filter x vertical angulation

10.27

2

5.13

8.42

0.000

0.000

0.000

error

241.46

396

0.61

       
Table 3: Repeated measures analysis of variance: reproducibility of radiographic measurements;
dependent variable: amount of the difference first minus second radiographic measurement (CEJ-DB)

 

 

CEJ-AC/mm

CEJ-BD/mm

magnification

7fold

14fold

7fold

14fold

measurements

mean± SD

mean±SD

mean±SD

mean±SD

intrasurgical

3.81 ± 1.72

 

9.05 ± 1.68

 

radiographic

       

examiner BW

       

without filter

4.55 ± 1.91

4.70 ± 1.93

9.12 ± 2.26

9.31 ± 2.25

D intra-without filter

-0.74 ± 1.67

-0.89 ± 1.65

-0.05 ± 1.65

-0.26 ± 1.71

spreading

4.81 ± 1.91

4.91 ± 1.96

9.24 ± 2.13

9.39 ± 2.21

D intra-spreading

-1.00 ± 1.76

-1.10 ± 1.71

-0.19 ± 1.59

-0.34 ± 1.64

structure

5.13 ± 1.99

5.28 ± 1.80

9.04 ± 2.28

9.26 ± 2.25

D intra-structure

-1.32 ± 1.78

-1.47 ± 1.58

0.00 ± 1.78

-0.21 ± 1.73

examiner EvB

       

without filter

4.73 ± 1.89

4.75 ± 1.87

9.01 ± 2.19

9.21 ± 1.96

D intra-without filter

-0.92 ± 1.74

-0.94 ± 1.69

0.04 ± 1.84

-0.16 ± 1.68

spreading

4.93 ± 1.84

4.83 ± 1.81

9.44 ± 2.27

9.53 ± 1.95

D intra-spreading

-1.12 ± 1.72

-1.02 ± 1.68

-0.39 ± 1.88

-0.48 ± 1.59

structure

5.23 ± 1.91

5.21 ± 1.81

9.82 ± 2.12

9.43 ± 1.91

D intra-structure

-1.91 ± 1.83

-1.40 ± 1.76

-0.77 ± 1.85

-0.38 ± 1.61

Table 4: Intrasurgical measurements and radiographic parameters (mean± standard deviation [SD]) and differences between intrasurgical and radiographic related to magnification and examiner.

 

source

SSQ

DF

MSQ

F-ratio

P

G-G

H-F

between subjects

intrasurgical CEJ-AC

178.61

1

178.61

15.30

0.000

   

error

1397.84

198

7.06

 

     

within subjects

filter

6.64

2

3.32

8.38

0.000

0.001

0.001

filter x intrasurgical CEJ-AC

0.39

2

0.19

0.49

0.613

0.575

0.577

error

156.95

396

0.40

       
Table 5: Repeated measures analysis of variance: validity of radiographic measurements (CEJ-AC);
dependent variable: Difference between intrasurgical and radiographic measurement (CEJ-AC)

 

source

SSQ

DF

MSQ

F-ratio

P

G-G

H-F

between subjects

examiner

5.09

1

5.09

0.67

0.415

   

magnification

0.89

1

0.89

0.12

0.733

   

examiner x magnification

1.90

1

1.90

0.25

0.619

   

intrasurgical CEJ-BD

73.13

1

73.13

9.57

0.002

   

horizontal angulation

51.31

1

51.31

6.72

0.010

   

error

1482.09

194

7.64

 

     

within subjects

Filter

1.13

2

0.56

1.55

0.213

0.214

0.214

filter x magnification

2.33

2

1.17

3.21

0.041

0.044

0.043

filter x examiner

8.05

2

4.02

11.09

0.000

0.000

0.000

filter x examiner x magnification

2.52

2

1.26

3.47

0.032

0.035

0.033

filter x intrasurgical CEJ-BD

1.40

2

0.70

1.93

0.147

0.150

0.148

filter x horizontal angulation

0.22

2

0.11

0.30

0.738

0.725

0.732

Error

140.82

388

0.36

       
Table 6: Repeated measures analysis of variance: validity of radiographic measurements (CEJ-BD);
dependent variable: Difference between intrasurgical and radiographic measurement (CEJ-BD)

Discussion and Conclusions

Conclusions

  • The chosen digital manipulations (filters: spreading, structure) of radiographic images failed to result in statistically significant more reproducible or valid measurements of interproximal bone loss within intrabony defects when compared to the digitized but unchanged images.
  • Radiographic assessments, except for the use of enhancement of grey level differences (structure) came close to the intrasurgical gold standard.

Abbreviations

Definition of landmarks
BD was defined as most coronal point where the periodontal ligament space showed a continuous width. If no periodontal ligament space could be identified the point where the projection of the AC crossed the root surface was taken as landmark. If both structures could be identified at one defect, the point defined by the periodontal ligament was used as BD. If several bony contours could be identified the most apical that crossed the root was defined as the BD.

This Poster was submitted on 02.02.01 by Dr. Eric von Bethlenfalvy.

Correspondence address:
Dr. Eric von Bethlenfalvy
Universität Heidelberg
Poliklinik für Zahnerhaltungskunde
Sektion Parodontologie
Im Neuenheimer Feld 400
D-69120 Heidelberg
phone: +49-6221-56 60 20
FAX: +49-6221-56 50 74