The reproducibility and repeatability of the Wits analysis

Observer agreement of imaging measurements used for evaluation of dentofacial deformity in juvenile idiopathic arthritis

OBJECTIVES

To examine the precision of imaging measures commonly used to assess mandibular morphology in children and adolescents with juvenile idiopathic arthritis (JIA). Secondly, to compare cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) in the measurement of condylar height.

METHODS

Those included were children diagnosed with JIA during 2015-18 who had had an MRI, a CBCT of the temporomandibular joints (TMJs) and a lateral cephalogram (ceph) of the head within one month of each other. Agreement within and between observers and methods was examined using Bland-Altman mean-difference plots and 95% limits of agreement (LOA). A 95% LOA within 15% of the sample mean was considered acceptable. Minimal detectable change (MDC) within and between observers was estimated.

RESULTS

90 patients (33 males) were included, with a mean age of 12.8 years. For MRI, intra- and interobserver 95% LOA were relatively narrow for total mandibular length: 9.6% of the sample mean. For CBCT, condylar height, both intra- and interobserver 95% LOA were wide: 16.0 and 28.4% of the sample mean, respectively. For ceph, both intra- and interobserver 95% LOA were narrow for the SNA-angle and gonion angle: 5.9 and 8% of the sample mean, and 6.2 and 6.8%, respectively.

CONCLUSIONS

We have identified a set of precise measurements for facial morphology assessments in JIA, including one MRI-based (total mandibular length), one CBCT-based (condylar height), and three ceph-based. Condylar height was higher for MRI than for CBCT; however, the measurement was too imprecise for clinical use. MDC was also determined for a series of measurements.

To check the reliability of various cephalometric parameters used for predicting the type of malocclusions and growth patterns

Background:

There are many different types of malocclusions that may result from the sagittal, vertical, or transverse deviations in normal craniofacial development. When it comes to orthodontic problems, malocclusions in the sagittal plane may have a considerable impact on a person's self-esteem as well as their ability to speak and eat properly. Sagittal anomalies in the skeletal, dental, and soft tissue systems may now be accurately diagnosed using a universally accepted standard lateral cephalogram (SLCE).

Methods and Materials:

The principal investigator manually traced the cephalograms, identified skeletal landmarks, and measured the following data. The ANB angle (normal range: 0° to 4°) is the angle framed by the point A, Nasion, and B. Estimated oppositely from point A and B on the functional occlusal plane, with Wits evaluation: AO-to-BO direct distance. AB plane angle : the angle formed by the AB and the Npog plane (normal range = -9° to 0°). Beta angle: the angle framed by the A-CB and AB lines, with a typical range of 27° to 35°. W angle: this is the angle created by the opposite line from M to the S-G line and the M-G line, with a typical range of 51 to 55 degrees. The angle of convexity: the angle between N-point A and A-Pog. (Normal range: -8.5 to 10 degree)

Results:

We utilised Pearson correlation to see how well the different skeletal studies correlated with one another. Wits and the ANB angle of convexity exhibited an excellent relationship with each other, with r = 0.831 and Downs angle of convexity (both r = 0.823 and P = 0.01) being statistically significant. This study used Kappa statistics to assess the degree of agreement between several cephalometric diagnostic criteria. The agreement between the ANB and final groups was strong (k = 0.802, P = 0.01).

Conclusion:

There was a strong link between all of the cephalometric measures. The cephalometric landmark and valid indication was determined to be the most dependable in evaluating malocclusion and development pattern.

[Use of skeletal-related diagnostic methods in articles published from 2018 to 2020 in four major orthodontics journals]

Objective

To determine the skeletal-related diagnostic methods most commonly used according to the four most important orthodontics journals in the period from 2018 to 2020.

Methods

A review of the data available regarding the diagnostic procedures most frequently used to determine skeletal relationships in the four most important orthodontics journals from 2018 to 2020. Article review was performed using SCIMAGO 2018, which provides a series of parameters ranking the importance of the impact of publications and journals. We made a synopsis of the information analyzed to establish a correlation and compare sources, and critically examined the articles collected on the subject of interest. An online bibliographic search of databases including mainly Medline was carried out, followed by evaluation and selection of the bibliography, organized according to the significance and nature of the study.

Results

The four journals included in the bibliographic search were: AJODO, AO, EJO and KJO. The A point-Nasion-B point (ANB) method was used in 92.2% of the articles published in AJODO, and 7.8% did not describe the method used. Twenty-three articles in the AO journal were evaluated, all of which referred to the use of ANB as the method used. Finally, 16 and 11 articles from the EJO and KJO journals, respectively, were evaluated, with 93.8% and 95%, respectively of the articles using ANB as the method of choice for determining skeletal relationships.

Conclusion

The method of choice for skeletal-related diagnostics is ANB, although this widely known method presents a risk of geometric effect.

MKG Angle: A True Marker for Maxillomandibular Discrepancy

Aim: To evolve a new cephalometric estimation called the MKG angle using three skeletal landmarks—point key ridge (KR), point M, and point G to evaluate the sagittal relationship between the maxilla and mandible.

Materials and methods: A total of 60 pretreatment lateral cephalograms were selected and segregated into classes I, II, and III groups on the basis of ANB angle, Wits appraisal, and W angle. The MKG angle was constructed between the lines drawn from point M to point KR and point KR to point G. The MKG angle was measured to calculate the mean and the standard deviation.

Results: After using the one-way analysis of variance and the Newman–Keuls test and running ROC curves, the results showed that an MKG angle in the range 51º–59º can be considered to have a class I skeletal pattern. The MKG angle more than 59º indicates a class II skeletal pattern and less than 51º indicates class III skeletal pattern.

Conclusion: The MKG angle can be used as a dependable marker to assess sagittal jaw discrepancy.

3D cephalometry on reduced FOV CBCT: skeletal class assessment through AF-BF on Frankfurt plane-validity and reliability through comparison with 2D measurements

OBJECTIVES

To test the validity of a novel protocol for 3D sagittal jaw discrepancy assessment (skeletal class determination) through comparison with common 2D indexes by the use of reduced FOV (10 × 10) CBCT which shows at least from the Frankfurt plane to the B point vertically, and from the most anterior between A and B point to Po point horizontally.

METHODS

A sample of CBCT scans of 109 adult patients (46 females; 63 males; mean age 30 years ± 11.6) equally distributed between I, II and III class was selected. Skeletal class was evaluated with specific software using the distance of A and B point's projection (AF-BF) on FHp (Frankfurt horizontal plane) and compared to 2D common indexes (ANB and Witts appraisal). The validity and reliability of the aforementioned analyses were determined using intra-class correlation coefficients, quadratic weighted Cohen's K and sensitivity.

RESULT

A selected range of values of 2.5 ± 2.5 AF-BF showed a solid correlation with the ANB angle (r = 0.846, K = 0.838, p < 0.001) and moderate with Wits appraisal (r = 0.723, K = 0.720, p < 0.001).

CONCLUSIONS

AF-BF showed high reliability in skeletal class determination on reduced FOV CBCT without the use of S and N cephalometric landmarks.

KEY POINTS

• Reduced FOV CT allows skeletal class determination for orthodontic purposes. • A new 3D-reduced FOV cephalometry is proposed. • AF-BF is a reliable alternative to ANB.

Newfangled Procedures Using X-ray to Determine the Cobb Angle in Patients with Scoliosis: An Updated Systematic Review

BACKGROUND

Scoliosis is a three-dimensional deformity of the spine. It is usually assessed by measuring Cobb angle. Nowadays, due to increasing effectiveness of image processing and machine vision, willingness to apply these methods has improved considerably in determining scoliosis of Cobb angle.

METHODS

In accordance with the PRISMA guideline, a broad electronic search of all English language literature was conducted on the topic through four databases, including MEDLINE, Web of Science, Scopus, and the Cochrane Library from 2012 (last search date from earlier review) to 30 March 2017.

RESULTS

Twelve studies were included. 90% labeled high-quality were selected for analysis. Eighty percent of the selected studies were published in the period between 2012 and 2017. Three new procedures were used to measure the Cobb angle. One study used automated procedure (7%), two studies used smartphone procedure (14%), and nine studies used the semiautomatic procedure of Cobb measurement (79%). Seven studies reported reproducibility and repeatability. Reproducibility range was 0.72 to 1 in reporting of ICC. Repeatability has a high range in three separated methods.

CONCLUSION

Computerized assessment method (Automatic and Semi-automatic) is most commonly performed in Cobb measurement. Semi-automatic is an effective measurement option for computerized assessment Cobb angle. There is no significant difference between manual, computer- based, and smartphone-based methods in described measures.

Sagittal discrepancies of the jaw in a Bangladeshi cohort: three-dimensional computed tomography analysis

Objectives

In orthodontic diagnosis and treatment planning, the assessment of skeletal jaw relationships is an essential step. This study aimed to evaluate skeletal jaw relationships in a Bangladeshi cohort by using traditional (ANB angle and Wits appraisal) and newly described (Beta angle, W angle, and Yen angle) sagittal measurements in three-dimensional (3D) computed tomography (CT).

Methods

The radiology department conducted CT scans of Bangladeshi patients. Mimics 3D imaging software (Materialise) was used to process the CT images and evaluate 3D sagittal measurements. SPSS software (IBM) was used to assess significant differences in the data at a confidence level of 5%. Independent-samples t-tests were used to evaluate sexual dimorphism for the measured values.

Results

In total, 85 men and 32 women were included in this study. All measurements were equivalent to the existing standards. There were no significant differences in the acquired values between men and women. Measurements were consistent with Class I normal classification.

Conclusions

This study established 3D CT standards for ANB, Wits appraisal, Beta angle, W angle, and Yen angle in Bangladeshi patients.

Diagnostic validity of different cephalometric analyses for assessment of the sagittal skeletal pattern

INTRODUCTION

Numerous cephalometric analyses have been proposed to diagnose the sagittal discrepancy of the craniofacial structures.

OBJECTIVE

This study aimed at evaluating the reliability and validity of different skeletal analyses for the identification of sagittal skeletal pattern.

METHODS

A total of 146 subjects (males = 77; females = 69; mean age = 23.6 ± 4.6 years) were included. The ANB angle, Wits appraisal, Beta angle, AB plane angle, Downs angle of convexity and W angle were used to assess the anteroposterior skeletal pattern on lateral cephalograms. The sample was classified into Class I, II and III groups as determined by the diagnostic results of majority of the parameters. The validity and reliability of the aforementioned analyses were determined using Kappa statistics, sensitivity and positive predictive value (PPV).

RESULTS

A substantial agreement was present between ANB angle and the diagnosis made by the final group (k = 0.802). In the Class I group, Downs angle of convexity showed the highest sensitivity (0.968), whereas ANB showed the highest PPV (0.910). In the Class II group, ANB angle showed the highest sensitivity (0.928) and PPV (0.951). In the Class III group, the ANB angle, the Wits appraisal and the Beta angle showed the highest sensitivity (0.902), whereas the Downs angle of convexity and the ANB angle showed the highest PPV (1.00).

CONCLUSION

The ANB angle was found to be the most valid and reliable indicator in all sagittal groups. Downs angle of convexity, Wits appraisal and Beta angle may be used as valid indicators to assess the Class III sagittal pattern.

A cross-sectional analysis of Wits and Riedel in adults with skeletal III malocclusion: How informative are they?

OBJECTIVES

To compare the relationship between Riedel and Wits appraisal in skeletal III malocclusions and to assess the effect of variation in the vertical skeletal measurements.

SETTING AND SAMPLE POPULATION

One-hundred and twenty consecutive subjects with Class III malocclusions attending orthognathic clinics were analysed.

MATERIALS AND METHODS

Lateral cephalograms were hand-traced under standardized conditions. Cephalometric measurements included Riedel analysis, Wits appraisal, A point/B point to Frankfurt plane (AF-BF) and vertical measurements.

RESULTS

The mean ANB and Wits values were -3.22° and -11.39 mm, respectively. A positive correlation was found between ANB and Wits overall (r = -.49; P < .001). However, there was poor agreement between both Wits (r = .087) and Riedel (r = .089) with AF-BF (P > .05). A negative correlation existed between Wits and LAFH% (r = -.64, P-value < .001); however, no relationship was observed between ANB and LAFH% (P > .05) based on linear regression analysis.

CONCLUSIONS

There is a positive relationship between ANB and Wits; however, neither correlated well with a purer antero-posterior assessment (AF-BF). Furthermore, variations in the vertical skeletal measurements affect the strength of agreement. Caution is advised in the interpretation of antero-posterior analysis especially in the presence of vertical discrepancy.

Reliability of Beta angle in assessing true anteroposterior apical base discrepancy in different growth patterns

Introduction:

Beta angle as a skeletal anteroposterior dysplasia indicator is known to be useful in evaluating normodivergent growth patterns. Hence, we compared and verified the accuracy of Beta angle in predicting sagittal jaw discrepancy among subjects with hyperdivergent, hypodivergent and normodivergent growth patterns.

Materials and Methods:

Lateral cephalometric radiographs of 179 patients belonging to skeletal Classes I, II, and III were further divided into normodivergent, hyperdivergent, and hypodivergent groups based on their vertical growth patterns. Sagittal dysplasia indicators - angle ANB, Wits appraisal, and Beta angle values were measured and tabulated. The perpendicular point of intersection on line CB (Condylion-Point B) in Beta angle was designated as ‘X’ and linear dimension XB was evaluated.

Results:

Statistically significant increase was observed in the mean values of Beta angle and XB distance in the vertical growth pattern groups of both skeletal Class I and Class II patients thus pushing them toward Class III and Class I, respectively.

Conclusions:

Beta angle is a reliable indicator of sagittal dysplasia in normal and horizontal patterns of growth. However, vertical growth patterns significantly increased Beta angle values, thus affecting their reliability as a sagittal discrepancy assessment tool. Hence, Beta angle may not be a valid tool for assessment of sagittal jaw discrepancy in patients exhibiting vertical growth patterns with skeletal Class I and Class II malocclusions. Nevertheless, Class III malocclusions having the highest Beta angle values were unaffected.

A new approach of assessing sagittal dysplasia: the W angle

In orthodontic diagnosis and treatment planning, an accurate antero-posterior measurement of jaw relationships is critically important. Previously described angular and linear measurements can be inaccurate because of their dependency on various factors. The purpose of this study was to introduce a new cephalometric measurement, named the W angle, to assess the sagittal relationship between maxilla and mandible with accuracy and reproducibility. This angle uses three skeletal landmarks--point S, point M, and point G--to measure an angle that indicates the severity and the type of skeletal dysplasia in the sagittal dimension. One hundred and forty-two pre-treatment cephalometric radiographs of patients between the age of 15 and 25 years were selected. They were again subdivided into Classes I, II, and III groups on the basis of Beta angle, Wits appraisal, and ANB angle. The W angle was measured between the perpendicular from point M on S-G line and the M-G line. The mean and the standard deviation for the W angle were calculated. After using the one-way analysis of variance and the Newman-Keuls test, receiver operating characteristics curves were obtained. Results showed that a patient with a W angle between 51 and 56 degrees can be considered to have a Class I skeletal pattern. With an angle less than 51 degrees, patients are considered to have a skeletal Class II relationship and with an angle greater than 56 degrees, patients have a skeletal Class III relationship.

Cephalometry

With the development of x-ray technology and its application to the craniofacial skeleton, numerous landmarks have been described and studied to better diagnose and plan treatment options for anomalies related to facial architecture. The following text serves to highlight the important landmarks and illustrate how they may be used to plan successful orthognathic reconstruction.

Influence of occlusal plane inclination on ANB and Wits assessments of anteroposterior jaw relationships

INTRODUCTION

Although assessments of anteroposterior relationships are vital for orthodontic treatment planning, they cannot be precisely achieved by current cephalometric and noncephalometric resources. ANB angle and the Wits appraisal are the most popular cephalometric measurements applied in clinical orthodontics, although they have drawbacks. Facial vertical features, especially the occlusal plane angle, play an important role in their assessment, contributing to their unreliability.

METHODS

To further understand the influence of occlusal plane inclination, ANB angle and the Wits appraisal were analyzed in cephalo-lateral radiographs of 122 finished orthodontic patients in 2 groups: high occlusal plane angle and low occlusal plane angle.

RESULTS

There was a tendency for inconsistency between ANB and Wits assessments in the high occlusal plane angle group and a tendency for consistency in the low occlusal plane angle group. Cranial base influences on ANB and Wits assessments were investigated by subdividing the groups. Any of the considered cranial base factors was decisive for lack or presence of consistency between ANB and Wits assessments.

CONCLUSIONS

The clinician should beware of possible misinterpretations when using ANB and Wits to assess the anteroposterior relationship of the jaws, especially in high occlusal plane angle patients.

A new approach of assessing sagittal discrepancies: the Beta angle

An accurate anteroposterior measurement of jaw relationships is critically important in orthodontic diagnosis and treatment planning. The angular and linear measurements that have been proposed can be inaccurate because they depend on various factors. The purpose of this study was to establish a new cephalometric measurement, named the Beta angle, to assess the sagittal jaw relationship with accuracy and reproducibility. This angle uses 3 skeletal landmarks-point A, point B, and the apparent axis of the condyle-to measure an angle that indicates the severity and the type of skeletal dysplasia in the sagittal dimension. Seventy-six pretreatment cephalometric radiographs of white patients were selected on the basis of 4 criteria that indicate a normal Class I skeletal pattern; the mean and the SD for the Beta angle were calculated. This group was compared with Class II and Class III skeletal pattern groups. After using the 1-way analysis of variance and the Newman-Keuls test and running receiver-operating-characteristics curves, we obtained results that showed that a patient with a Beta angle between 27 degrees and 35 degrees can be considered to have a Class I skeletal pattern. A more acute Beta angle indicates a Class II skeletal pattern, and a more obtuse Beta angle indicates a Class III skeletal pattern.

Comparative study of diagnostic measures in borderline surgical cases of unilateral cleft lip and palate and noncleft Class III malocclusions

Patients with complete unilateral cleft lip and palate present difficult growth problems. Their anteroposterior discrepancies in jaw and dentition are frequently so severe that some epidemiologic studies report the necessity of orthognathic surgery in 25% of their sample. The aims of this study were three-fold: (1) to delineate diagnostic measures in borderline surgical cases of unilateral cleft lip and palate, (2) to verify the significance of negative overjet as a measure of anteroposterior discrepancy, and (3) to compare these diagnostic measures with those of borderline surgical cases of noncleft Class III malocclusions. The sample consisted of 29 patients with unilateral cleft lip and palate and 25 noncleft Class III Korean patients (mean age, 18.69 years); all had crossbites of all four incisors. Each of their pretreatment study casts and cephalograms were analyzed. The group with unilateral cleft lip and palate was divided into two subgroups on the basis of the method of their anterior crossbite resolution; 18 subjects were treated with orthodontics alone (Cleft-NS) and 11 subjects with orthognathic surgery (Cleft-Surg). The noncleft Class III group was divided into two subgroups; 6 of the subjects were orthodontically treated (Cl III-NS), and 19 were surgically treated (Cl III-Surg). The group with unilateral cleft lip and palate showed smaller SNA and SNB angles than the noncleft Class III group, but the ANB angles and the amount of anterior crossbites showed no statistical differences. When the Cleft-NS and the Cleft-Surg groups were compared, the ANB angle and the Wits measurements were significantly different. When the Cl III-NS and Cl III-Surg groups were compared, the SNB, ANB, L1GoGn, Wits, and the crossbite showed significant differences. For borderline surgical Class III unilateral cleft lip and palate cases, ANB angle, Wits appraisal, and ABGoGn angle were critical diagnostic parameters. On the other hand, the magnitude of anterior crossbite, the negative overjet, was shown not to be a significant measure of anteroposterior discrepancy.