Apical Base Relationship Research Articles

Mount Vernon Index vs Yen Angle for Assessment of Anteroposterior Apical Jaw Base Relationship.

Aims and objectivesThis research aimed to determine the predictability and variability of the Yen angle and Mount Vernon Index (MVI) in relation to the other four sagittal discrepancy parameters, as well as to evaluate and explain any correlations that exist. The Lateral Cephalograms of 100 Class I Indian participants aged 17–24 years were recorded. The lateral cephalograms were traced for six distinct AP characteristics, including ANB, Wits appraisal, facial convexity, and beta angle, Yen angle, and MVI. The gathered data were evaluated statistically using S.P.S.S. version 10. To determine the difference between males and females, an independent “t” test was used. The coefficient of variability and correlation methods were used to determine the correctness of the Yen angle and MVI, as well as the association between the variables.ResultsThe results of this study indicate that the most predictable and highly dependable parameter was the Yen angle (CV = 5.63), followed by the beta angle (5.63), the MVI (CV = 13.6), the ANB, Rickett's analysis, and Wit's analysis. Throughout all five analyses, the most statistically significant positive association between the MVI and the BETA angle was determined.ConclusionThe derived inferences from the study included the high reliability of the yen angle for assessing the AP skeletal patterns of a patient, followed by the beta angle and MVI.How to cite this articleDoshi JR, Jain P, Jain M, et al. Mount Vernon Index vs Yen Angle for Assessment of Anteroposterior Apical Jaw Base Relationship. Int J Clin Pediatr Dent 2021;14(S-1):S35–S38.

Growth Pattern in Skeletal Class I Malocclusion: A Cephalometric Study

Introduction: Great emphasis has been given to the evaluation of sagittal apical base relationship in orthodontic diagnosis and treatment planning. The prediction of magnitude and direction of facial growth based on sagittal relationship will help in orthodontic treatment with growth modification. The objective of the study is to assess the growth pattern in skeletal Class I malocclusion. Materials and Method: 104 subjects (52 male and 52 female) with the age between 18-30 years with Class I skeletal relation was selected from lateral cephalograms of patients visiting the Department of Orthodontics, Kantipur Dental College. The ANB angle was measured to assess the sagittal jaw relationship and the Jarabak’s ratio to access the growth pattern. Descriptive statistics were calculated for each parameter. Pearson’s test was done to evaluate the correlation between the parameters. Independent t-test was done to compare Anterior Facial height (AFH), Posterior Facial Height (PFH) and Jarabak’s ratio between male and female subjects. Result: Among the total subjects with skeletal Class I malocclusion; hyperdivergent growth pattern was least (10.57%), followed by normodivergent (18.26%) and hypodivergent growth pattern (71.15%). Mean Jarabak’s ratio for hyperdivergent, normodivergent and hypodivergent growth pattern were 58.65±1.94, 63.98±0.85 and 69.98±4.13 respectively. Very strong correlation was found between AFH and PFH in hyperdivergent (r = 0.821) and normodivergent group (r =0.978). Strong correlation was found in hypodivergent group between AFH and PFH (r =0.743). Also, strong correlation was found in hypodivergent group between PFH and Jarabak’s ratio (r =0.643). Conclusion: Hypodivergent growth pattern was the dominant growth pattern in skeletal Class I malocclusion. PFH influenced the determination of Jarabak’s ratio more than the AFH in hypodivergent growth pattern. Hypodivergent growth pattern is correlated with large SNB angle.

Cephalometric Comparison of Wits Appraisal and APP-BPP to the ANB Angle

Introduction: Great emphasis has been given to the evaluation of sagittal apical base relationship in orthodontic diagnosis and treatment planning. Supposedly, the most commonly used parameter is “ANB angle”; however its accuracy and reliability have been questioned. Many authors have alternatively introduced linear parameters like Wits appraisal and APP-BPP. The objective of the study was to compare Wits appraisal and APP-BPP with the ANB angle.
 Materials & Method: This study was conducted on patients visiting the Department of Orthodontics, Kantipur Dental College, Kathmandu. The sample included 100 lateral cephalograms of subjects of the age group 18–30 years with skeletal Class I relation. Parameters like ANB angle, Wits appraisal and APP-BPP were measured to assess the sagittal jaw relationship. Descriptive statistics were calculated for each parameter. Spearman’s test was done to evaluate the correlation between the parameters. Mann-Whitney U test was done to compare the parameters between male and female subjects.
 Result: Descriptive statistics showed that the mean values of ANB, Wits appraisal and APP-BPP were 2.26±1.19°, 0.38±0.87mm and 3.25±1.20mm respectively. Mann-Whitney U test showed no significant difference among the parameters between the gender groups (p>0.05). Spearman’s test showed significant correlation among the parameters ANB angle, Wits appraisal and APP-BPP. The parameters had strong positive correlation as r value was greater than 0.7.
 Conclusion: The strong positive correlation between ANB angle, Wits appraisal and APP-BPP indicates that these parameters can be used as better adjunct to ANB angle in orthodontic diagnosis and treatment planning.

Assessment of Sagittal Skeletal Base Relationship of Maxilla and Mandible by Horizontal Appraisal Method—A Comparative and Reliability Study

Introduction: The evaluation of antero-posterior apical base relationship is crucial before orthodontic diagnosis and treatment planning. Aim and Objectives: The present study is aimed to compare the credibility of five cephalometric measurements in assessing the antero-posterior jaw relationship and to assess the correlation between various measurements used for antero-posterior discrepancy, including ANB, Yen angle, Beta angle, Wits appraisal, and horizontal appraisal. Materials and Methods: A total of 99 patients aged 16 years and above patients were subdivided into skeletal Classes I, II, and III groups of 33, each based upon the ANB angle derived from the pretreatment cephalogram. Results: The results showed that AH/BH and ANB had very high sensitivity and specificity to discriminate a Class II from Class I and Class III from Class I. Wits, YEN, and Beta showed lower specificity to differentiate Class II from Class I and Wits and Yen to differentiate Class III from Class I except Beta which had 100% sensitivity to differentiate Class III from Class I. Conclusion: The horizontal appraisal method enriches the current cephalometric tools available for the clinician to assess the antero-posterior jaw relationship accurately and reproducibly.

Long-term stability of Class II treatment with the Jasper jumper appliance.

Treatment of Class II Division 1 malocclusion with orthopedic devices combined with fixed orthodontic appliances has shown excellent results when used in growing patients. We aimed to evaluate the long-term stability of the cephalometric changes obtained during Class II malocclusion correction with the Jasper jumper associated with fixed appliances. The treatment group comprised 24 patients who were evaluated at 3 stages: pretreatment, posttreatment, and long-term posttreatment. The control group comprised 15 subjects with normal occlusion. Intratreatment group comparisons among the 3 stages were performed with repeated measures analysis of variance, followed by Tukey tests. Intergroup comparisons of posttreatment changes and normal growth changes of the treatment group were performed with t tests. Apical base relationship, maxillary incisor anteroposterior position, and overjet demonstrated significant relapses in relation to the control group. Most dentoalveolar changes obtained with the Jasper jumper followed by fixed appliances during treatment remained stable in the long term. However, apical base relationship, maxillary incisor anteroposterior position, and overjet demonstrated significant relapses in relation to the control group. Therefore, active retention time should be increased in the posttreatment period.

Long-term stability of Class III malocclusion nonextraction treatment

BackgroundThe aim of this study was to evaluate the long-term stability of successful therapy of patients with Class III malocclusion at the end of facial growth. Materials and methodsThe experimental group comprised 18 patients with Class III malocclusion treated without extractions with a mean age of 11.8 years (SD 2.8) at pretreatment, 15.7 years (SD 1.8) at posttreatment, and 24.1 years (SD 5.4) at follow-up. The control group comprised 22 subjects with normal occlusion observed during a comparable period. Intragroup treatment changes were analyzed with paired t tests, and intergroup posttreatment changes were compared with t tests. A multiple regression analysis was used to evaluate the influence of all variables in the amount of overjet relapse. ResultsIn the long-term, the experimental group demonstrated no significant change in apical base relationship. A significant decrease in overjet and overbite was observed but both remained positive. The primary factor that contributed to the overjet decrease was the mandibular growth in the posttreatment period. There were no significant intergroup differences regarding skeletal changes during the posttreatment period; however, the maxillary and mandibular incisors had significantly different behavior in the experimental as compared with the control group. ConclusionsIn the long-term, nonextraction Class III malocclusion treatment demonstrated clinical stability in 88.9% of the patients. The dentoskeletal improvements obtained with treatment remained stable during the posttreatment period. The greater amount of mandibular growth after active treatment was the major variable that determined instability of Class III malocclusion treatment.

Comparative assessment of sagittal skeletal discrepancy: a cephalometric study.

Evaluating the sagittal apical base relationship during orthodontic diagnosis and treatment planning is an important step. This study was aimed at comparison of Beta angle, ANB angle and Wit's appraisal for assessment of sagittal skeletal discrepancy. Eighty six young adults (43 female and 43 male) were selected from the patient's reporting to Department of Orthodontics, College of Dental Sciences, Davangere, India. Family lineage was studied to know the nativity of Davangere. The standardized pre-treatment lateral cephalogram of the chosen sample was traced. The sample was divided into three skeletal pattern groups: Class I, Class II and Class III, based on the ANB angle and profile, Beta angle was assessed in each group. The data was subjected to statistical analysis student's t-test, ANOVA test and correlation and regression analysis, using the software namely SPSS Software version 13. Microsoft word and Excel were used to generate graphs and tables. In the local Davangere population, Class I skeletal pattern group exhibited Beta angle between 26°-34°, Beta angle less than 27° was found in Class II skeletal pattern, and Beta angle greater than 32° was seen Class III skeletal pattern. The coefficient of variation of Beta angle in all the three groups was significantly homogenous compared to ANB angle and Wits appraisal. The correlation and regression analysis of the total sample indicated a highly significant correlation between Beta angle and ANB angle (p<.001), and between Beta angle and Wits appraisal (p<.01). Beta angle can be used to classify subjects into different skeletal patterns. The Correlation and regression analysis for the total sample suggests a highly significant relation between Beta angle and ANB angle and, between Beta angle and Wits appraisal. It can be more reliably used to assess sagittal jaw discrepancies than ANB angle and Wits appraisal.

Stability of Class II treatment with the Bionator followed by fixed appliances

ObjectiveThis prospective study assessed the stability of Class II treatment with the Bionator, followed by fixed appliances, 10 years after treatment. Material and MethodsThe experimental group comprised 23 patients of both sexes (10 boys, 13 girls) at a mean initial age of 11.74 years (late mixed or early permanent dentitions), treated for a mean period of 3.55 years who were evaluated at three stages: initial (T1), final (T2) and long-term posttreatment (T3). A total of 69 lateral cephalograms were evaluated and 69 dental casts were measured using the PAR index. The difference between initial and final PAR indexes, the percentage of occlusal improvement obtained with therapy and the percentage of relapse were calculated, using the PAR index. The variables were compared by repeated measures analysis of variance (ANOVA) followed by Tukey tests. ResultsThe significant improvement in apical base relationship, the palatal inclination of the maxillary incisors and the labial inclination of the mandibular incisors, and the significant improvement in molar relationship and reduction of overjet and overbite, obtained with treatment, remained stable in the long-term posttreatment period. There was also significant improvement in the occlusal relationships which remained stable in the long-term posttreatment period. The percentage of occlusal improvement obtained was of 81.78% and the percentage of relapse was of 4.90%. ConclusionsTreatment of Class II division 1 malocclusions with the Bionator associated with fixed appliances showed to be stable in the long-term posttreatment period.

Long-term stability of Class II malocclusion treated with 2- and 4-premolar extraction protocols

The objective of this study was to cephalometrically compare the stability of complete Class II malocclusion treatment with 2 or 4 premolar extractions after a mean period of 9.35 years. A sample of 57 records from patients with complete Class II malocclusion was selected and divided into 2 groups. Group 1 consisted of 30 patients with an initial mean age of 12.87 years treated with extraction of 2 maxillary premolars. Group 2 consisted of 27 patients with an initial mean age of 13.72 years treated with extraction of 4 premolars. T tests were used to compare the groups' initial cephalometric characteristics and posttreatment changes. Pearson correlation coefficients were calculated to determine the correlation between treatment and posttreatment dental-relationship changes. During the posttreatment period, both groups had similar behavior, except that group 1 had a statistically greater maxillary forward displacement and a greater increase in the apical-base relationship than group 2. On the other hand, group 2 had a statistically greater molar-relationship relapse toward Class II. There were significant positive correlations between the amounts of treatment and posttreatment dentoalveolar-relationship changes. Treatment of complete Class II malocclusions with 2 maxillary premolar extractions or 4 premolar extractions had similar long-term posttreatment stability.

Editor's Summary and Q&A: Long-term stability of Class II malocclusion treated with 2- and 4-premolar extraction protocols

Introduction The objective of this study was to cephalometrically compare the stability of complete Class II malocclusion treatment with 2 or 4 premolar extractions after a mean period of 9.35 years. Methods A sample of 57 records from patients with complete Class II malocclusion was selected and divided into 2 groups. Group 1 consisted of 30 patients with an initial mean age of 12.87 years treated with extraction of 2 maxillary premolars. Group 2 consisted of 27 patients with an initial mean age of 13.72 years treated with extraction of 4 premolars. T tests were used to compare the groups' initial cephalometric characteristics and posttreatment changes. Pearson correlation coefficients were calculated to determine the correlation between treatment and posttreatment dental-relationship changes. Results During the posttreatment period, both groups had similar behavior, except that group 1 had a statistically greater maxillary forward displacement and a greater increase in the apical-base relationship than group 2. On the other hand, group 2 had a statistically greater molar-relationship relapse toward Class II. There were significant positive correlations between the amounts of treatment and posttreatment dentoalveolar-relationship changes. Conclusions Treatment of complete Class II malocclusions with 2 maxillary premolar extractions or 4 premolar extractions had similar long-term posttreatment stability.

Geometric Influence of the Sagittal and Vertical Apical Base Relationship on the ANB Angle

The objective of this study consisted in determining the variability of the ANB angle in relation to the position of the A- and B-points in the sagittal vertical plane. Using a theoretical model, we varied the position of the cephalometric points A and B in the sagittal vertical plane while its sagittal relationship was kept constant (Wits value = 0 mm). For this purpose, seven lines were erected perpendicular to the occlusal plane on a lateral cephalogram. The position of points A and B were determined on each of the vertical lines by calculating one anterior and one posterior angle in each case. In this way, the positions of all A- and B-points were clearly defined in the sagittal vertical plane. The characteristic of the ANB angle in the sagittal vertical plane was graphically represented by determining both points A and B using two angles instead of one. This revealed that the ANB angle for the same sagittal base relationship was characterized by major variations depending on the position of the A- and B-points in relation to the anterior cranial base. The larger the SNA and SNB angles were, the larger the corresponding ANB angle. At the same time, the absolute value of ANB increased with the length of the vertical distance between the points A and B. The ANB angle is strongly influenced by geometric factors. Accurate diagnosis of the sagittal base relationship should thus take the individual character of the ANB angle into account.

Orthodontic Treatment Combined with Mandibular Distraction Osteogenesis and Changes in Stomatognathic Function

We performed an orthodontic treatment combined with mandibular distraction osteogenesis in a 15-year-old patient who wanted a correction of a chin deficiency and a protruding upper lip. The patient had an Angle Class II division 1 malocclusion with mandibular retrusion, a low mandibular plane angle, and scissors bite. First, a quad-helix appliance was applied to the mandibular dentition to correct the scissors bite in the bilateral premolar region. Later, a preadjusted edgewise appliance was applied to the maxillary and mandibular teeth. After 3 days, a mandibular distraction osteogenesis was performed. During and after the distraction, the open bite between the upper and lower dental arches was corrected using up and down elastics. The total treatment time with the edgewise appliance was 14 months. A skeletal Class I apical base relationship, good facial profile, and optimum intercuspation of the teeth were achieved with the treatment. The jaw-movement pattern on the frontal view did not change during gum chewing. However, the maximum gap without pain increased. The electromyographic (EMG) activity of the masseter and anterior temporalis muscles, and maximum occlusal force increased. The present case report suggests that an orthodontic treatment combined with mandibular distraction osteogenesis in a patient with mandibular retrusion in the late growth period might be effective for improving stomatognathic function.

Biological derivation of a range of cephalometric norms for children of African American descent (after Steiner)

The purpose of this study was to report a normal range of anteroposterior apical base differences and concomitant interincisor inclinations and locations derived from a sample of American children (12 to 16 years) of African descent with normal occlusion (statistically defined). Standard cephalometric radiographs of 40 boys and 40 girls were traced and the Steiner Analysis performed. In addition to the ANB angle, 6 supplemental anteroposterior apical base separation estimators were measured, mean values established, and correlation (r ) associations performed. The range of anteroposterior apical base difference was –0.5° to 9.5° estimated by the ANB angle or a linear distance of ±6.5 mm using the Wits Appraisal. The angular and linear distance of the upper incisor to NA line (compensations) ranged from a low of 12° and 3 mm to a high of 39° and 14 mm. The angular and linear distance of the lower incisor to the NB line ranged from a low of 17° and 3 mm to a high of 47.5° and 17.5 mm. Biologically, the results suggested a wide range of equally acceptable sagittal apical base relationships and associated compensations in upper and lower incisor inclinations; normal occlusion was viewed as the reference point. Considering the usage of such descriptive terms as “ideal,” “acceptable compromises,” and “individualized treatment goals,” to describe the angulation and inclination of the incisor teeth, the need for a distinction between biologically derived reference norms and esthetic preference reference norms is apparent when analyzing normal occlusion. (Am J Orthod Dentofacial Orthop 2000;117:90-101)

A Cephalometric Study of Changes in Point A under the Influence of Upper Incisor Inclinations.

Today the ANB angle is commonly used for defining the anteroposterior apical base relationships of the jaws. The factors that influence the ANB angle have been studied by various investigators. The axial inclination of the maxillary central teeth is one of the factors influencing the location of point A. In this study the relationship between the axial inclination of the upper central incisor and the location of point A was studied. Four criteria that define the location of the maxillary central teeth were used: I (incisal point), Ap (apical point), R (rotation point), and I-SN (angle between I and SN plane). A significant positive correlation was found between the location of points A and R. We also calculated a regression equation for this relationship.

Update on the Wits appraisal.

A review of various aspects of the application of the Wits appraisal of anteroposterior apical base relationships since its introduction in 1975.

The influence of heredity and environment on six variables describing incisor orientation.

The relationship between genetic and non-genetic factors was studied for six variables associated with incisor positioning. The aim was to determine the heritability for the anteroposterior apical base relationship, the overjet and the inclinations of upper and lower incisors. The path analysis model was used on twin material to separate genetic and cultural inheritance. No evidence was found to indicate any significant influence of cultural inheritance. Heritability quotients (role of genetic factors in the total variance) varied with the highest value for the anteroposterior apical base relationship (h2 = 0.8) followed by lower incisor inclination (h2 = 0.7) and with the lowest values for overjet and the upper incisor inclination (h2 = 0.5 and 0.4). A calculation of the quotient between genetic and environmental standard deviations showed corresponding results, indicating that genetic factors may have twice as much influence as non-genetic ones on the apical base relation, (quotient = 2.1) followed by lower (1.4) and upper (1.1) incisor inclinations and overjet (0.9).

A cephalometric evaluation of hard and soft tissue changes during class III traction.

In this retrospective cephalometric study, the lateral skull radiographs of 12 children with Class III malocclusions of skeletal origin were examined. An analysis of the changes produced during treatment revealed that whilst changes in apical base relationship were small, and were mainly limited to a reduction in angle SNB, the effects on the soft tissue profile were surprisingly effective.

Dento-alveolar compensation for antero-posterior variations between the upper and lower apical bases.

Two groups consisting of 68 adult singletons and 42 adult pairs of twins were studied with respect to antero-posterior variations in the apical base relationship and its association with the incisor overjet and upper and lower incisor inclinations. A weak correlation with the overjet was established while stronger associations were found with incisor inclinations especially regarding the lower incisors. A large positive apical base relation thus seems to be primarily compensated for by proclination of the lower incisors while negative values caused a corresponding retroclination. When associated correlation coefficients were compared with previously published value somewhat stronger associations were found. In addition when average incisor compensations for variations in the apical base relationship were compared with Steiner's model they were found to be slightly greater than that recommended by him.

Longitudinal changes in the ANB angle and Wits appraisal: Clinical implications

The changes in the ANB angle and the Wits appraisal between the ages of 5 and 25 years were evaluated in twenty male and fifteen female subjects. All subjects had clinically acceptable occlusions, and none had undergone orthodontic therapy. Descriptive statistics were calculated, and analysis of variance was performed. The conclusions derived from this investigation are as follows: (1) No significant differences were observed in the changes between male and female subjects for either ANB or Wits between age 5 and adulthood. (2) The ANB angle changes significantly with age, while the Wits appraisal indicates that the relationship between points A and B does not change significantly with age. (3) Correlation coefficients showed that the ANB angle and the Wits appraisal are significantly correlated but the r-values are relatively low. These findings explain the discrepancies that are present in some cases between the measured values of the ANB angle and the clinical judgment of the orthodontist. For a more accurate diagnosis of the anteroposterior apical base relationship, both the ANB angle and Wits appraisal should be used.

The JYD angle: A modified method of establishing sagittal apical base relationship: Seppo Jarvinen Eur. J. Orthod. 4:243–248, 1982

The JYD angle: A modified method of establishing sagittal apical base relationship: Seppo Jarvinen Eur. J. Orthod. 4:243–248, 1982