Reproducibility and accuracy of measuring unerupted teeth using limited cone beam X-ray CT

Mesiodistal Measurements for Dental Implant Planning: A Prospective Clinical Study of Linear Measurements on Cone-Beam Computed Tomography Images in Comparison with Caliper-Based Measurements on Plaster Casts

Althouh cone beam computed tomography (CBCT) is popular for dental implant planning, the horizontal mesiodistal space of the edentulous ridge is still conventionally measured with a handheld sliding caliper in the oral cavity or on a plaster cast. For clinical application in implant planning, our aim was to evaluate the accuracy of CBCT horizontal mesiodistal linear measurements in comparison with conventionally obtained direct measurements on plaster casts. Postoperative CBCT acquisitions and plaster casts of 27 patients with adjacent posterior mandibular implants were analyzed in a prospective clinical study. On CBCT images, two observers assessed the inter-implant distances on axial and sagittal views. On plaster casts, the inter-implant distances were measured with a digital caliper. CBCT measurements on axial and sagittal views were, on average, 0.2 mm larger than measurements on plaster casts. Correlation was perfect between measurements of the same inter-implant distance performed by the observers on CBCT images and on plaster casts. When compared with conventionally obtained direct measurements on plaster casts, CBCT views slightly overestimated (mean 0.2 mm) the horizontal mesiodistal measurements between two implants as reference points. CBCT imaging is sufficiently accurate to evaluate mesiodistal distances on axial and sagittal views for dental implant planning in clinical practice.

Comparative evaluation of the precision of cone-beam computed tomography and surgical intervention in the determination of periodontal bone defects: A clinicoradiographic study

Context

Major limitations of conventional radiography are overlapping and lack of 3D information. Surgical exposure, though being able to provide accurate information, provides very little time to plan-out the type of periodontal regeneration required during surgery. Cone Beam Computed Tomography (CBCT) has emerged as a feasible tool and found to be accurate. Unfortunately, in-vivo studies are still scarce.

Aim

Aim of the present study was to assess the efficacy of CBCT in the detection of periodontal bony defects while determining its quantitative precision in the measurement of alveolar bone height as against the open flap debridement (OFD) procedure which is set as the gold standard.

Setting and Design

Present study is a cross-sectional study.

Materials and Methods

The present study includes patients with Chronic Periodontitis indicated for periodontal surgeries. Bone defects were measured with the help of CBCT and with William's periodontal probe during surgical intervention and compared.

Statistical Analysis

Measurements were compared with Student's t-test; unpaired t-test & correlation were tested with Pearson's correlation coefficient test. P < 0.05 was considered statistically significant.

Results

The mean CBCT & surgical value of palatal/lingual & distal sites of anterior teeth showed statistically significant difference (P = 0.001). All the values for posterior teeth were statistically non-significant.

Conclusion

Statistically CBCT & clinical measurement with OFD have similar potential of accuracy to access the bony topography but CBCT provides good accessibility to visualize the sites which are difficult to access during surgical interventions like palatal sites & the distal sites of the posterior teeth.

A comparative study of cone beam computed tomography and conventional radiography in diagnosing the extent of root resorptions

Background

Root resorptions are assessed and diagnosed using different radiographical techniques. A comparison of the ability to assess resorptions on two-dimensional (2D) and three-dimensional (3D) radiographs is, hitherto, lacking. The aims of this study were to evaluate the accuracy of 2D (periapical radiographs, PA and panoramic radiograph, PAN) and 3D (cone beam computed tomography, CBCT) radiographic techniques in measuring slanted root resorptions compared to the true resorptions, a histological gold standard, in addition to a comparison of all the radiographic techniques to each other.

Methods

Radiographs (CBCT, PA, and PAN), in addition to histological sections, of extracted deciduous canines from thirty-four patients were analyzed. Linear measurements of the most and least resorbed side of the root, i.e., “slanted” resorptions, were measured using an analyzing software (Facad ®). For classification of slanted root resorptions, a modified Malmgren index was used.

Results

PAN underestimated the root length on both the least and most resorbed side. Small resorptions, i.e., low modified Malmgren scores, were more difficult to record and were only assessed accurately using CBCT. The root resorption scores were underestimated using PA and PAN. In assessment of linear measures, PAN differed significantly from both CBCT and PA.

Conclusions

CBCT is the most accurate technique when measuring and scoring slanted root resorptions.

Evaluation of the accuracy of cone beam computed tomography on measuring impacted supernumerary teeth

Supernumerary teeth may affect the tooth eruption negatively if they occur on the eruption way, and the treatment choice is usually the extraction to prevent the impaction of adjacent permanent teeth. CBCT enables clear and three dimensional images, and it may be helpful to determine the exact location and to measure the dimensions of the supernumerary tooth to avoid any complication during the extraction process. The aim of the present study was to evaluate the accuracy of CBCT on measuring the tooth length and crown width of impacted supernumerary teeth. Twenty-five impacted supernumerary teeth were evaluated using CBCT, and each sample's tooth length and crown width were measured prior to the extraction. After all the extractions were completed, the actual measurements were performed on the same samples. The differences between CBCT and actual measurements were evaluated statistically. Measurements on CBCT images were significantly larger than the actual measurements on tooth length and crown width. For tooth length and crown width, p value was found as 0.045, and <0.001, respectively. The results of the present study should be considered as important by clinicians during the treatment planning to decrease any complication risk under certain conditions such as being so close to an important anatomical structure or the root of an adjacent tooth. SCANNING 38:579-584, 2016. © 2016 Wiley Periodicals, Inc.

Asymmetric Dental Development Investigated by Cone-Beam Computed Tomography in Patients With Unilateral Cleft Lip and Alveolus

OBJECTIVE

To investigate a possible delay in dental development of cleft-side teeth compared with the contralateral teeth in patients with unilateral cleft lip and alveolus with or without cleft palate (UCLA ± CP) and to correlate this delay to developmental stages of the corresponding teeth.

DESIGN

Cross-sectional study.

SETTING

Cleft Lip and Palate Care Center of Shanghai Ninth People's Hospital, Shanghai, China.

PATIENTS

Forty Chinese patients with UCLA ± CP.

MAIN OUTCOME MEASURE

Crown height (CH), root length (RL), and full length (FL) of permanent incisors, canines, premolars, and first molars were measured using cone-beam computed tomography and compared between cleft and noncleft sides. Discrepancies in tooth length between sides during different developmental stages of delayed teeth were also compared.

RESULTS

There were no statistically significant differences in tooth length between sides in the mandible, except for RL of lateral incisors and RL and FL of the second premolars. In the maxilla, CH, RL and FL of cleft-side incisors, as well as RL and FL of cleft-side canines and first premolars, were all significantly shorter than those on the noncleft side (P < .05). The lateral incisors showed the highest reductions in RL and FL (47% and 29%). Moreover, reduction of RL of cleft-side maxillary central incisors was most evident in the early developmental stage (23%) and decreased with dental maturation (5%).

CONCLUSIONS

Asymmetric dental development was presented in both jaws but mainly in maxillary anterior region. The RL deficiency of cleft-side central incisors differed at different developmental stages.

How do dentists use CBCT in dental clinics? A Norwegian nationwide survey

OBJECTIVES

Cone beam computed tomography (CBCT) was introduced to Norwegian dental clinics in 2007. The aim of the study was to investigate how dental clinics use this imaging modality, including factors related to workflow and image quality, and to evaluate dentists' opinions on and experiences of using it.

MATERIALS AND METHODS

A web-based 59-item questionnaire regarding the clinical use of CBCT was sent to all 39 CBCT clinics in Norway.

RESULTS

Twenty-nine clinics (74%) responded. Most respondents (93%) were from clinics with more than one dentist and 83% had at least one specialist. All clinics had digital intraoral x-ray receptors and all but one had panoramic imaging. The most common indications for CBCT were implant treatment planning (34% of all clinics) and localization of impacted teeth (43% of specialist clinics). Seventy-two per cent of clinics reported an average of four or fewer CBCT examinations each week and 83% of respondents were subjectively satisfied with the image quality. The most commonly used enhancement functions were contrast (97%), brightness (90%) and zoom (86%).

CONCLUSIONS

The Norwegian CBCT clinics surveyed were fully digitized and had multiple dentists. Periodontists and oral and maxillofacial surgeons were the most frequent specialties represented in the clinics. Clinics with only dental specialists performed more CBCT examinations/week than clinics with general practitioners or both general practitioners and specialists. The most common indications for CBCT examinations were related to treatment planning. This study found some challenges related to image quality and communication within the radiological team.

A comparative study of accuracy of linear measurements using cone beam and multi-slice computed tomographies for evaluation of mandibular canal location in dry mandibles

Background:

Cross- sectional tomograms have been used for optimal pre-operative planning of dental implant placement. The aim of the present study was to assess the accuracy of Cone Beam Computed Tomography (CBCT) measurements of specific distances around the mandibular canal by comparing them to those obtained from Multi-Slice Computed Tomography (MSCT) images.

Materials and Methods:

Ten hemi-mandible specimens were examined using CBCT and MSCT. Before imaging, wires were placed at 7 locations between the anterior margin of the third molar and the anterior margin of the second premolar as reference points. Following distances were measured by two observers on each cross-sectional CBCT and MSCT image: Mandibular Width (W), Length (L), Upper Distance (UD), Lower Distance (LD), Buccal Distance (BD), and Lingual Distance (LID). The obtained data were evaluated using SPSS software, applying paired t-test and intra-class correlation coefficient (ICC).

Results:

There was a significant difference between the values obtained by MSCT and CBCT measurement for all areas such as H, W, UD, LD, BD, and LID, (P < 0.001), with a difference less than 1 mm. The ICC for all distances by both techniques, measured by a single observer with a one week interval and between 2 observers was 99% and 98%, respectively. Comparing the obtained data of both techniques indicates that the difference between two techniques is 2.17% relative to MSCT.

Conclusion:

The results of this study showed that there is significant difference between measurements obtained by CBCT and MSCT. However, the difference is not clinically significant.

Tooth lengths of the permanent upper incisors in patients with cleft lip and palate determined with cone beam computed tomography

Objective : To measure the tooth lengths of fully developed permanent upper incisors and to qualitatively evaluate the root shapes of the incisors in patients with cleft lip and palate (CLP). Design : Cross-sectional, noninterventional, case-control imaging study. Setting : Hospital and Stomatology Unit of Peking University, Beijing, China (institutional tertiary care). Participants : Sixty consecutive nonsyndromic CLP patients (including 40 unilateral [UCLP] and 20 bilateral [BCLP]), and 53 age- and sex-matched controls were selected for this study. Main Outcome Measure : Crown heights and root lengths of permanent upper incisors were measured from cone beam computed tomography scans, and the root shapes of upper incisors were evaluated. Results : Compared with controls, the crown heights of upper incisors in CLP patients were reduced by 9.7% to 22.5% (p < .05), and the root lengths were reduced by 15.8% to 31.7% (p < .05). BCLP patients had greater reductions than the UCLP cases (p < .05). There were no significant differences between incisors and their antimeres in controls and BCLP patients. However, measurements on the cleft side in UCLP patients were lower than those of the noncleft side (p < .05). The prevalence of atypical root shape was higher in CLP than in the control group (p  =  .002); of these, 83.3% (30/36) occurred in central incisors near the cleft. Conclusion : The permanent upper incisors in nonsyndromic CLP patients are underdeveloped. Incisor developmental deficiency was greater in teeth adjacent to the cleft.

Detection of dental root fractures by using cone-beam computed tomography

OBJECTIVES

The purpose of this study was to compare the diagnostic accuracy of cone beam CT (CBCT) with that of conventional dental radiography in the detection of root fractures and to evaluate the influence of root canal fillings on root fracture detection.

METHODS

We investigated 128 patients with clinically suspected root fractures in 135 teeth. These patients underwent conventional dental radiography, CBCT and eventually surgical exploration. Among the 135 teeth, 86 were non-endodontically treated teeth and 49 were endodontically treated teeth. Two oral radiologists independently analysed the dental radiographs and CBCT images of each patient and reached a consensus. The CBCT findings of root fractures were set as the detection of a separation of the adjacent root segments on at least two contiguous sections and on at least two of the three-dimensional (3D) planes.

RESULTS

Root fracture was intraoperatively detected in 95 of the 135 teeth. The sensitivity and specificity of root fractures diagnosed on the basis of the consensus between the 2 evaluators were 26.3% and 100%, respectively, for dental radiography and 89.5% and 97.5%, respectively, for CBCT. CBCT was significantly more accurate than dental radiography in detecting root fractures (P < 0.001). The sensitivity of CBCT was reduced in the presence of root canal fillings but its specificity remained unaffected. Both the sensitivity and specificity of dental radiography were not influenced by the presence of root canal fillings.

CONCLUSIONS

CBCT appears to be more accurate than conventional dental radiography in the detection of root fractures.

Measuring mesiodistal width of impacted maxillary canines: CT-assisted determination

AIM

Precise, three-dimensional localization of impacted maxillary canines is central to their clinical management. Predicting precisely the crown's mesiodistal width is paramount in planning orthodontic treatment. The aim of this study was to verify the exact mesiodistal width of impacted canines via MSCT (multislice spiral computed tomography) examinations.

PATIENTS AND METHODS

3D MSCT images from 17 patients with a total of 24 impacted maxillary canines were taken to obtain the largest mesiodistal diameter using mesial and distal contact points. All existing maxillary canines were included in this study. Mesiodistal tooth width was also determined using callipers on a plaster model after canine eruption. Each measurement was taken twice by 3 observers after a 10-day interval. Statistical analysis entailed calculating and comparing the systematic error, intrarater and interrater standard deviations (Deming regression and ANOVA with random effects).

RESULTS

Comparison of the different methods revealed good agreement between the pre-eruption and post-eruption values regarding the canine's mesiodistal width. Total standard deviation was 0.16 mm for values obtained from MSCT measurements and 0.12 mm for those taken with callipers. For both methods intrarater measurement error differed by a factor of 2 (repeatability; model versus MSCT: 0.07 mm versus 0.12 mm), while interrater deviation did not differ significantly (reproducibility; model versus MSCT: 0.10 mm versus 0.10 mm). The reproducibility of our measurements whether taken on the model or with CT was below biological variability.

CONCLUSIONS

The volumetric data from an MSCT system gives highly accurate information on the mesiodistal width of displaced canines.

Three-dimensional volume tomographic study of the imaging accuracy of impacted teeth: MSCT and CBCT comparison--an in vitro study

The aim of this study was to analyze the imaging accuracy of cone beam computed tomography (CBCT) data sets compared with multislice spiral computed tomography (MSCT) data sets in determining the exact mesiodistal width of unerupted porcine tooth germs and to compare the radiologically obtained results of width measurements with the actual mesiodistal dimension of the tooth germs. In MSCT and CBCT data sets, the largest diameter of 24 tooth germs was determined with the aid of the mesial and distal contact points. The reference method used was mesiodistal width measurement using sliding callipers after the tooth germs had been osteotomized. Accuracy and precision were ascertained with difference plots and a one-way model II analysis of variance with random effects. Analysis of accuracy revealed marked differences between the measuring methods in the difference plot: slightly higher mean values were measured by MSCT and markedly lower values by CBCT than by the reference method (calliper); the mean deviation was significantly greater for CBCT. The width of the confidence interval in the comparison of CBCT versus clinical measurements is more than 4 times higher than in the comparison of MSCT versus clinical values. Precision analysis found that repeatability was twice as high with CBCT as with clinical measurement, whereas MSCT and clinical measurement differed only slightly. The mesiodistal width of displaced teeth can be determined by MSCT but also by CBCT. MSCT is superior to CBCT in determining tooth width; the difference was statistically significant (P = 0.05).

Mesiodistal width and proximal enamel thickness of maxillary first bicuspids

This study aimed at evaluating measurements relative to the mesiodistal crown width and enamel thickness of maxillary first bicuspids. The sample consisted of 40 extracted sound bicuspids (20 right and 20 left), selected from white patients (mean age: 23.7 +/- 4.2 years), who were treated orthodontically with tooth extraction at a private clinic in São Paulo, SP, Brazil. All teeth were embedded in acrylic resin and cut along their long axis through the proximal surfaces, parallel to the buccal side, to obtain 0.6-mm central sections. The mesiodistal crown width and proximal enamel thickness were measured using a stereoscopic microscope connected to a computer. Measurements for right and left teeth, as well as the mesial and distal enamel thicknesses in the total sample, were compared by the Wilcoxon test (alpha = 0.05). The mesiodistal crown width mean values found were 7.51 mm (+/- 0.54) on the right side and 7.53 mm (+/- 0.35) on the left side. The mean enamel thickness on the distal surfaces for both sides was 1.29 mm (right: s.d. = 0.12 and left: s.d. = 0.18). The mean values for the mesial surfaces were 1.08 mm (+/- 0.14) and 1.19 mm (+/- 0.25), on the right and the left sides, respectively. No significant differences were found between the crown measurements and enamel thicknesses on the left and right sides. However, enamel thickness was significantly greater on the distal surfaces. Reliable measurements of enamel thickness are useful to guide stripping, which may be an attractive alternative to tooth extraction because it allows the transverse arch dimension to be maintained.

Accuracy and precision of linear measurements in cone beam computed tomography Accuitomo tomograms obtained with different reconstruction techniques

OBJECTIVES

To assess the accuracy and precision of linear measurements, the influence of different object positions in cone beam CT (CBCT) images and the effect of different systems for reformatting and viewing the tomograms on measurement values.

METHODS

An object consisting of Plexiglas plates with metal spheres was radiographically examined in three positions using the CBCT unit Accuitomo. Tomograms were reformatted using the i-Dixel software and Sectra picture archiving and communication system (PACS) multiplanar reformatting (MPR). Two observers measured 20 linear distances in axial, frontal and sagittal planes. Physical measurements of actual distances by means of a digital caliper served as the gold standard.

RESULTS

For measurements performed on the Accuitomo and Sectra PACS workstations, the mean differences between repeated measurements were below 0.13 mm (standard deviation (SD) 0.13 mm) and 0.21 mm (SD 0.18 mm), respectively. Mean differences between the two observers were below 0.11 mm (SD 0.07 mm) and 0.15 mm (SD 0.09 mm). The mean difference between the gold standard and the basic position when using the Accuitomo workstation, was -0.08 mm (SD 0.21 mm) and for a deviated/rotated position -0.08 mm (SD 0.23 mm) and -0.09 mm (SD 0.20 mm). None was statistically significant (P > 0.05). For measurement performed on MPR tomograms using the Sectra PACS workstation, mean differences were -0.09 mm (SD 0.17 mm) for basic position, and -0.08 mm (SD 0.19 mm) and -0.13 mm (SD 0.15 mm) for deviated and rotated positions, respectively. The mean difference between gold standard and basic/rotated positions was statistically significant, with P = 0.032 and P = 0.002.

CONCLUSIONS

Our study confirms previous findings indicating that measurements in 3DX Accuitomo FPD (flat panel detector) tomograms show a high level of agreement with actual distances. Our findings suggest the possibility of minor distortion in tomograms reformatted by means of Sectra PACS MPR.

Measurements of mandibular canal region obtained by cone-beam computed tomography: a cadaveric study

OBJECTIVE

The objective of this study was to assess the accuracy and reproducibility of cone-beam CT measurements of specific distances around the mandibular canal by comparing them to direct digital caliper measurements.

METHODS

Six formalin-fixed hemimandible specimens were examined using the ILUMA cone-beam CT system. Images were obtained at 120 kVp, 3.8 mA, and a voxel size of 0.2 mm, with an exposure time of 40 seconds. Specimens were cut into sections at 7 locations using a Lindemann burr, and a digital caliper was used to measure the following distances on both the anterior and posterior sides of each section: Mandibular Width (W); Mandibular Length (L); Upper Distance (UD); Lower Distance (LD); Buccal Distance (BD); and Lingual Distance (LID). The same distances were measured on the corresponding cross-sectional cone-beam CT images using the built-in measurement software. All caliper and cone-beam CT measurements were made by 2 independent trained observers and were repeated after an interval of 1 week. The Bland/Altman method was used to calculate intra- and inter-rater reliability. Intra-class correlation coefficients (ICCs) from 2-way random effects model were calculated. Agreements between cone-beam CT and direct digital caliper were calculated by ICC for 6 distances and 2 observers.

RESULTS

Intraobserver and interobserver measurements for all distances showed high agreement. ICCs for intraobserver agreement ranged from 0.86 to 0.97 for cone-beam CT measurements and from 0.98 to 0.99 for digital caliper measurements. ICCs between observers ranged from 0.84 to 0.97 for the cone-beam CT measurements and from 0.78 to 0.97 for the digital caliper measurements. ICCs for cone-beam CT and direct digital caliper ranged from 0.61 to 0.93 for the first observer and from 0.40 to 0.95 for the second observer.

CONCLUSION

Accuracy of cone-beam CT measurements of various distances surrounding the mandibular canal was comparable to that of digital caliper measurements.

Accuracy and repeatability of cone-beam computed tomography (CBCT) measurements used in the determination of facial indices in the laboratory setup

AIM

To assess the three dimensional (3D) surface accuracy of a phantom's face acquired from a cone-beam computed tomography (CBCT) scan and to determine the reliability of selected cephalometric measurements performed with Maxilim software (Medicim N.V., Mechelen, Belgium).

MATERIAL AND METHODS

A mannequin head was imaged with a CBCT (I-CAT, Imaging Sciences International, Inc., Hatfield, USA). The data were used to produce 3D surface meshes (Maxilim and Mimics, Materialise N.V., Leuven, Belgium) which were compared with an optical surface scan of the head using Focus Inspection software (Metris N.V., Leuven, Belgium). The intra- and inter-observer reliability for the measurement of distances between facial landmarks with Maxilim 3D cephalometry were determined by calculating Pearson correlation coefficients and intraclass correlation (ICC). The Dahlberg formula was used to assess the method error (ME).

RESULTS

(1) The maximal range of the 3D mesh deviations was 1.9 mm for Maxilim, and 1.8mm for Mimics segmentation. (2) Test-retest and inter-observer reliability were high; Pearson's correlation coefficient was 1.000 and the ICC was 0.9998. The ME of the vertical measurements was a little larger than that calculated for the width measurements. Maximum ME was 1.33 mm.

CONCLUSIONS

The 3D surface accuracy of CBCT scans segmented with Maxilim and Mimics software is high. Maxilim also shows satisfactory intra- and inter-assessor reliability for measurement of distances on a rigid facial surface.