Contribution of the craniofacial structures to facial heights and depth in malocclusions: untraditional cephalometric analysis

The contribution of the craniofacial structures and their correlations to the malocclusions were investigated in 94 cases with different malocclusions, and compared to 29 subjects with normal occlusion [16 females and 13 males] as control group collected from Tanta secondary school. The malocclusion cases were collected from Orthodontic Department, Faculty of Dentistry, Tanta University. It includes 32 cases with class I [18 females and 14 males], 22 cases with class II, division [14 females and 8 males], 12 cases with class II, division 2 [7 females and 5 males], 17 cases with class III [6 females and 11 males], and II cases with class III have surgically repaired clefts [6 females and 5 males]. All the cases enrolled in this study have ages above 15 years and had not received any type of prosthetic work or any type of orthodontic treatment. A cephalometric x-ray was done for each case and analyzed with untraditional measurements including S-Gn-AB, A-SN perpendicular, Pog-SN perpendicular, upper incisor to SN-perpendicular at A point, and effective length of the maxilla and the mandible. Statistical analysis with t test for unequal variance was used for comparison between cephalometric measurements of females and males in normal subjects and malocclusion cases. While, coefficient correlation were done for some parameters to investigate the contribution and relation of these parameters to malocclusions. The results of this investigation indicate the following; a-In class II, division 1, there are, increase of the effective length of the maxilla, while the mandible within normal, increased lower anterior facial height. increased anterior cranial base length, increased maxillary depth, increased A-SN perpendicular, increased S-Gn-AB and increase of the mandibular ramus height. There are a decrease in, facial depth, cranial deflection angle, and upper anterior facial height. B-In class II, division 2, there is a decrease of lower anterior facial height, however the mandibular length within normal c-In class III malocclusion there are increase in effective mandibular length, Pog-SN perpendicular, facial depth, cranial deflection angle and decrease in all other measurements. D-In class II, division 1 and class III malocclusion [both sexes]; there are negative correlation in S-Gn-AB/Pog-SN perpendicular, effective maxillary length/upper anterior facial height, and effective mandibular length/lower anterior facial height. While, positive correlations were observed in S-GN-AB/A-SN perpendicular and anteriol cranial base length/ A-SN perpendicular [both sexes]. f-In class II, division 2 malocclusion, no correlations were found in S-GN-AB/Pog.-SN perpendicular and effective mandibular length/lower anterior facial height, In conclusion, a-Reliability of S-GN-AB angle for discrimination between classes especially in cases with large variability of nasion position except in class II, division 2 where the retroclination of upper central incisors must be considered. b-The most probable cause of class II malocclusion is the increase of the maxillary length or more anterior position of the maxilla in relation to the anterior cranial c-The most probable causes of class III malocclusion are the increase of the effective mandibular length and decrease of the maxillary effective length. d-In cleft cases with class III malocclusion, the underdeveloped maxilla in vertical and anteroposterior length are the proposal cause of class III while, all the cleft cases displayed normal mandibular length

Persistent thumb sucking habit and associated dental and skeletal abnormalities in class I and class II, division 1 malocclusions in mixed dentition

This study was designed to investigate the associated dental and skeletal abnormalities in mixed dentition period for boys and girls with age ranged from 9 to 11 years old and exhibited persistent thumb sucking habit until the time of investigation. The investigation was performed on 39 cases with malocclusion, constitute 18 cases with class I malocclusion [10 girls and 8 boys] and 21 cases with class II, division 1 malocclusion [10 girls and 11 boys]. They were collected from the Orthodontic clinic, Faculty of Dentistry, Tanta University and some private orthodontic clinics. Another 22 children with normal occlusion at the same age range [12 girls and 10 boys] were selected from the Pedodontic clinic, Faculty of Dentistry, Tanta University from those seeking simple conservative treatment. On investigation, all dental abnormalities including spacing, lower arch crowding, posterior cross-bite, anterior open-bite and rotation of teeth were recorded in table 1 for class I malocclusion and table 2 for class II, division 1 malocclusion. Cephalometric x-ray and study model analysis for each subject enrolled in this study were done including variables that denote the most expected areas affected by the persistence of the thumb sucking habit. Examples, sagittal position of the maxilla, effective maxillary length, and effective mandibular length, lower inter canine width and palatal depth. The results of this investigation indicate that, in both genders with class I malocclusion, 30% of the cases have class II canine relationship which is dominant in boys and more than 90% of the cases displayed spacing in anterior area with less frequently involve canine's area. It also displayed more than 30% of the cases have anterior open bite, rotation [more in girls] in lower anterior and posterior cross-bite. While, impaction of the lateral incisor as the result of lower imbrications and congenital missing teeth constituted 10% of the investigated cases. In class II, division 1 malocclusion, more than 40% of the investigated cases have lower anterior crowding and rotation and more than 50% have posterior cross-bite. Upper spaces are also present in nearly all the cases including the canine's area with anterior open-bite, which constituted nearly 50% of the cases [both genders]. The cephalometric and study model analysis displayed the following: No statistically significant differences were recorded between genders, While, in comparison of class I to normal children, the palatal depth only displayed significant difference on study model analysis in both genders and all the recorded cephalometric variables except the effective mandibular length displayed statistically significant differences. In class II, division 1 malocclusion, the results displayed statistically significant differences of all cephalometric variables except lower incisor to mandibular plane angle and lower inter-molar width in model analysis. The following can be concluded from this investigation; 1-Spaces in upper anterior area and rotation of lower anterior teeth are the most common associated anomalies in class I and class II, division 1 malocclusion. 2-Posterior cross-bite and lower anterior crowding are more prominent in class II, division 1 malocclusion than class I malocclusion. 3-The premaxilla is the most affected part in middle face as the result of the persistent thumb sucking in vertical and sagittal heights. 4-Increase LAFH and decrease of UAFH, UADH, and LADH are the dental and skeletal effects of the persistent thumb sucking habit in class I malocclusion. 5- In class II, division 1 malocclusion, there are increase of LAFH, LADH and decrease of UAFH and UADH

The relationship of the glenoid fossa position and functional occlusal plane in skeletal class III malocclusion with anterior open bite

The correlation of the glenoid fossa position to the occlusal planes in twenty-three skeletal class III malocclusion cases with anterior open-bite were investigated. The sample was collected from the Orthodontic patients in Orthodontic Department, Tanta University. They were selected with the ANB angle less than zero angles. Another twenty-one subjects with normal occlusion were collected from the secondary school students used as control group. All the subjects enrolled in this investigation have an age above seventeen years old. The geometric center of the glenoid fossa was first identified by using a transparent template containing a series of circles whose diameter increased in one-millimeter increments with demarcated centers. The largest circle that nearly fit and tangent to the superior, anterior, and posterior surfaces of the glenoid fossa, was determined. The distance from sella turcica to this center and the perpendicular heights from this center to the lower and upper occlusal planes were measured. The heights that affect the cant of the occlusal plane were measured which are the upper and lower anterior and posterior dental heights. The relationship of the glenoid fossa position represented by S-GC-F1 and S-GC- F2 angles [F1 and F2 are the intersection of the perpendicular from GC on the lower and upper occlusal plane respectively] to the cant of the upper and lower occlusal planes which represented by the length of GC-F1 and GC-F2 were correlated by coefficient correlation test. The results of this study indicate increases of theses angle in both genders of class III with anterior open-bite than in normal subjects. While, the distance from the geometric center to the lower occlusal plane were decreased and increased to the upper occlusal plane in the malocclusion cases than normal. The results also indicate positive correlation between the glenoid fossa position represented by S-GC-F1 angle and the cant of the lower occlusal plane [represented by GC-F1 height] while, no correlation exist between its position represented by S-GCF2 angle and the cant of upper occlusal plane [represented by GC-F2 heigh]. It also indicates decreases in upper anterior and posterior dental height that may attributed most probably to the character of the skeletal, class III cases represented in maxillary deficiency or underdeveloped maxilla

In conclusion: 1- There is a positive correlation between the glenoid fossa position and the cant of the lower occlusal plane. 2- Very weak negative correlation between the glenoid fossa position and the cant of upper occlusal plane. 3- Drawing one colossal plane in midway between incisors to the medial cusp of the first molar teeth is adequate in diagnosis of class III malocclusion with anterior open-bite. 4- Growth problems [underdeveloped or overdeveloped] of the middle cranial fosse has direct effect on the globoid fosse position and consequently on the mandibular position and the cant of lower occlusal plane. 5-There are increase in lower anterior and posterior dentoalveolar heights and decrease of upper anterior and posterior dentoalveolar heights in class III malocclusion with anterior open-bite cases than normal occlusion

Aim of the study: The purpose of this study was to investigate the position of the glenoid fossa in untreated adult skeletal class III malocclusions with anterior open-bite to the functional occlusal plane in males and females to reach through diagnosis and treatment planning particularly in orthognathic cases