شهین امامی میبدی

Class II and Class III malocclusions have been reported to have a high incidence among the antero-posterior jaw anomalies. This study is aimed to evaluate the relation between the antero-posterior discrepancies and morphology of the cervical vertebra. This case control study evaluated 89 patients(aged 17 to 30 years old). The samples were matched based on vertical dimension indices such as SN-MP, MM, and Jarabak index. ANB index was used to divide the samples into 2groups as follows 1- Control group consisting of 39 subjects with normal growth pattern(ANB2+2 2- Case group with 20 Class II (ANB>4) subjects and 30 Class III (ANB<0) subjects.. Cervical vertebra morphology was assessed on lateral cephalograms and anomalies such as posterior arch deficiency and fusion were detected. Data were analyses by Binary logistic Regression, T test and Independent sample test. The prevalence of fusion was 35.9% in control group (normal growth pattern), 55% in Class II, and 73.3 % in Class III. The difference was statistically significant between control group and Class II malocclusion as well as Class III malocclusion. (p<0.003) (p<0.01). There was no significant difference in prevalence of fusion between Class II and Class III malocclusion groups. The prevalence of posterior arch deficiency was 5.5%, 15%, and 16.7 % in normal growth pattern, Class II, and Class III groups respectively. The difference.(p<0.8. p<0.9. p<0.5) There was a significant relation between anteroposterior discrepancies and cervical vertebra anomalies, especially for C2 and C3.

Timing is an important factor in orthodontic treatment planning. Skeletal age is a standard indicator for determining optimum time for treatment. On the other hand, in clinic the phases of the dentition (deciduous, early and late mixed, permanent) have often been used for treatment timing, investigations of the different outcomes of treatment protocols at earlier vs later stages of development. Considering the importance of this issue and to evaluate it in the Iranian adolescents, the purpose of this study was to evaluate the relation between clinical phases of dental eruption and the skeletal maturity stages by cervical vertebrae method (CVM). Panoramic radiographs and lateral cephalograms of 100 boys and 100 girls were used. For determination of the Phases of dentition, Vander Linden method and for the skeletal maturity, CVM were used. The relationship between the skeletal maturity (stages in CVM) and the phases of the dentition was evaluated statistically by means of indicators of diagnostic tests and spearman’s rho analysis. Spearman’s rho analysis indicated a relatively strong correlation of 0.775 (P<0.001); The early mixed dentition phase was a valid indicator of prepubertal stage (CS1), but the late mixed and early permanent dentitions were not valid indicators for the diagnosis of the onset of the pubertal growth spurt (CS3). In comparison with a reliable indicator of skeletal maturity (CVM), the dentition phases perform poorly in the detection of the onset of the pubertal spurt in skeletal growth. Key words: Phases of dental eruption, skeletal maturity, CVM.

Considering the prevalence of skeletal open bite and existing controversies around the relation between pharyngeal dimensions and dentofacial as well as craniofacial structures, the aim of this study was to investigate the pharyngeal dimensions in CLII division I subjects with and without skeletal open bite malocclusion. This case control, double blind study was based on paraclinical data obtained through close analysis of files, cepholograms and study models. A total of 40 subjects, including 19 male and 21 females (mean age: 65.14± 1.53 yrs) were selected based on the maxillary-mandibular plan angle, SN-Mandibular plan angle, Y-Axis and Tarabak Index. The study group was divided into two groups. The case group included 20 subjects with skeletal open bite and the control group consisted of 20 subjects without skeletal open bite. The pharyngeal dimensions including nasopharyngeal, oropharyngeal and Hypopharyngel, depths were measured. The length of the airway and the distance between the hyoid bone and the mandibular plane were also recorded. Data was analyzed by T-test. There was no significant difference between the two groups in terms of Nasopharyngeal, Oropharyngeal and Hypopharyngeal dimensions. Significant statistical difference was found between the length of the airway in the case group (62.4± 3.78) and the control group (15.75± 3.76) (p<0.03). There was also statistically significant difference between the distance of Hyoid bone to mandibular plane in the case group (15.75± 3.76) and the control group (12.1± 3.64) (p<0.003). There was an increase in both variables in the case group. The Nosopharyngeal, Oropharyngeal and Hypopharyngeal depths are not associated with skeletal open bite The length of the airway and the Hyoidbone- Mandibular plane distance could affect the growth pattern. Pharyngeal dimensions or respiration patterns have no effect on the growth pattern.

Facial growth pattern is one of the important factors in orthodontic treatment planning. The aim of this study was to compare the inclination of the posterior teeth in subjects with a normal and vertical growth pattern. Fifty 16 to 20 year old individuals having no history of orthodontic treatment, dental extraction, spacing and crowding in posterior teeth were selected for this case – control study. These individuals were divided into two groups of vertical and normal growth patterns based on SN-MP and Jarabak Index. Study casts provided for these patients were trimmed from anterior to the second premolar and from posterior to the first molar. Lateral surfaces of casts were trimmed perpendicular to the occlusal surface tangential to the most prominent cusps of these 4 or at least 3 (two molars and one premolar) teeth. The angle between lateral surface of the cast and the occlusal surface of each tooth was considered as axial inclination. The results were statistically analyzed using Mann Whitney U and t tests. The mean age of the studied group was 18.3±1.6. The mean axial inclination of maxillary first permanent molar with normal growth pattern was 27.5±16.8 (right side) and 26.2±14.7 (left side). The amount of this variable with vertical growth pattern was 23.4±11.9 (right side) and 24.8±14.7 (left side). The mean axial inclination of mandibular first permanent molar with normal growth pattern was 27.24±15.2 (right side) and 27.44±14.8 (left side) and with vertical growth pattern was 23.8±13.9 (right side) and 23.5±14.3 (left side). Buccolingual inclination of the teeth has no effect on orthodontic treatment planning.

The prevalence of Cl II malocclusion is high in the population. The functional appliances are used in the patient who has mandibular deficiency. The present study was aimed to compare the dentoskeletal changes of CLII/I Malocclusion who used inclined anterior bite plan and modified FRII. The material consisted of 30 patients, with Cl II/I malocclusion, ANB > 4º in late mixed dentition. Half of the patients (9 girls and 6 boys) were treated by inclined anterior bite plane and reminder (8 girls and 7 boys) by modified FRII appliance. Lateral cephalogroms were obtained and traced before and after treatment and certain angular and linear variables were measured. The pretreatment and post-treatment measurements were compared using Mann-whitney U test and Wilcoxon Test to evaluate the significancy of the results. Significant changes mainly caused by mandibular growth, were observed after treatment by modified FRII and inclined anterior bite plane. This study indicated no statistical significant differences between two groups except Ar-B and AR-Pog. Considering the less bulky anterior inclined bite plane and its easier construction we can use this appliance instead of modified FRII.

Recently, interest has been focused on pharyngeal dimensions because of a potential relationship between size and structure of upper airway and sleep-induced breathing disturbances Significant relationships between the pharyngeal structures and both dentofacial and craniofacial structures have been reported The aim of this study was to investigate the pharyngeal space dimensions in subjects with different malocclusion on the private clinic in Tehran in 2004-2008 Cephalometric radiograph of 90 subjects (45 females and 45 males, aged 12–18 years) were included with the following criteria: no history of orthodontic treatment; breathing comfortably through the nose; normal vertical occlusal relationship (Max/Man planes angle 25.5° ± 5) and divided into three groups according to the ANB angle, group 1, skeletal ClassⅠ(ANB angle 1–5); group 2, skeletal Class Ⅱ (ANB angle >5); and group 3, skeletal Class Ⅲ (ANB angle <1). In addition, each group was divided into two subgroups according to sex. Statistical analysis was undertaken using analysis of 2-way ANOVA and least significant difference test. Lateral skull radiographs were traced on acetate paper and 12 hard and soft tissue cephalometric points were registered yielding 12 linear measurements Sex differences were found in Class Ⅰ and Ⅱ and Ⅲ subjects. The female has bigger SPAS/MIS and SPAS/IAS than male and the HRGN/C3H has increase in female than male. The distance between hyoid bone and C3 is longer in class Ⅲ than class Ⅱ.The height of airway space was reduced in Class Ⅱ male subject compared with class ⅠandⅢ.We found relationship between ANB and position of hyoid bone to C3H and tongue length and tongue height.VAL was significantly reduced in class Ⅱ subjects compared with classⅢ& Ⅰ in male The results showed that malocclusion can change the position of hyoid bone to mandibular plan and C3H and the vertical air way space in male. We found the relation sip between ANB angle and tongue and hyoid bone. we found Sex differences were detected in superior airway and the position of hyoid bone.

The prevalence of Cl II malocclusion with tongue thrust and open bite is high. The pressure of the tongue during swallowing and its physiological activity could be transferred to the maxillary complex by the tongue crib and might advance the maxilla to an unfavorable position. This study aimed to evaluate the dentoskeletal change in the Cl II division 1 patients with anterior tongue thrust and mandibular deficiency treated by mandibular tongue guard, from a private office and orthodontic department of Azad University in Tehran. Methods & Materials: The sample consisted of 23 patients, (14 females aged 8 years and 9 months and 9 males aged 10 years and 6 months), with Cl II div 1 malocclusion in late mixed dentition with anterior tongue thrust. The patients were treated by mandibular tongue guard. Lateral Cephalograms were obtained and traced before and after treatment and certain angular and linear variables were measured. The pretreatment and post treatment measurements were compared using Paired t test to evaluate the significance of the results. The findings indicated that SNB, facial angle, the distance between B and Pogonion to the reference line and Interincisal angle were significantly increased (P<0.05). The changes were mainly caused by mandibular growth, were observed after treatment by mandibular tongue guard. Decrease of IMPA, 1-SN, ANB, Wits were significant (P<0.05). The changes of Jarabak index, SN-MP, SNA, Y-axis were not significant. In Cl II div 1 patients with mandibular deficiency combined with tongue thrust, mandibular tongue guard caused slight increase in mandibular growth.

While planning for orthodontic/orthopedic treatment, using maturation indices to measure the skeletal maturity level is inevitable in evalating the patient’s growth. A new method is based on morphologic changes of cervical vertebrae which can be readily seen on lateral cephalogram. In this diagnostic study we aimed to compare this new method determining skeletal maturity level with conventional method (Hand-Wrist). 80 subjects (19 males and 61 females) contributed in the study. Each subject had a lateral Cephalogram and Hand-wrist radiogram taken simultaneously. Maturation level was diagnosed based on atlas vertebras, represented by both methods and in following, data were analyzed. Correlation coefficient between two methods was calculated by Spearman’s analysis and reliability of this new method of diagnosis the skeletal maturity was measured by McNemar’s statistical test. The sensivity and specificity of lateral cephalogram were 98.2% and 88%, respectively. Also, the positive and negative predictive values were 94.7% and 95.6% for this modality. Correlation coefficient between both methods was 93%. The reliability and reproducibility of the new method in determining the skeletal maturity was 95%. High correlation and reliability obtained between both methods suggesting the applicability of the new methods to determine skeletal maturity.

With regard to the vertical problem of skeletal open bite malocclusion and using posterior bite plane this study was undertaken to evaluate the effect of upper posterior bite plane on the dentoskeletal changes in patients with skeletal open bite The material consisted of 19 patients, with skeletal open bite in mixed dentition period. The patients were treated by upper removable posterior bite plane appliance. Lateral Cephalogrom before and after treatment was obtained and traced. Certain angular and linear variables were measured. The pre treatment and post treatment measurements were compared using Paired t-test to evaluate the significance of the results. . There were significant changes in vertical incisor overlap following treatment with upper posterior bite plane.. Increase of PFH, Jaraback index UAFH/LAFH ratio were significant. There was decrease of SN-MP angle The dentoalveolar heights of the upper and lower anterior segment were increased as well as the distance of the lower molars to vertical and sagital lines only the maxillary first molar height and its distance to the vertical reference line did not change. The use of upper removable posterior bite plane during mixed dentition period in skeletal open bite patients causes counter clockwise rotation of mandible and an increase in the posterior facial height.