Showing 8 results for III
H. Ravanmehr , D. Abdollahi ,
Volume 13, Issue 3 (10-2000)
Abstract
In this investigation, the position of hyoid bone was compared in three skeletal groups of class I, II and III. The study was based on evaluating 77 lateral cephalometric radiographs, 40 girls and 37 boys, which were divided into 3 groups. Group 1, 2, and 3 consist of 26, 25, and 26 radiographs. 19 cephalometric landmarks and 10 planes were used in order to tracing the radiographs. In all patients, 9 skeletal and 4 cervical vertebrae parameters were measured to determine the hyoid bone. These parameters were compared between three skeletal groups regardless of sex and then, in another statistical analysis, parameters were compared based on patients sex. Statistical analysis showed that in class III patients, the hyoid bone was positioned more anteriorly than two other groups. Also in this group, the hyoid bone had less inclination and it was more horizontal in relation to mandibular plane. In skeletal class II patients this bone was positioned more superiorly than two other groups. Due to these findings it can be concluded that perimandibular muscles and bones could affect the growth of mandible. In addition, comparison of the parameters between two sexes revealed that the hyoid bone was positioned more anteriorly and inferiorly in boys. Also it was shown that in the girls, the position of hyoid bone was closer to the position of this bone in skeletal class I patients.
A. Khavari , T. Hossein-Zadeh-Nik ,
Volume 14, Issue 4 (1-2002)
Abstract
Electromyographic (EMG) investigations about the activities of the muscles have been the focus of attention for many years. In the field of orthodontics, investigators, among other things, tried to evaluate correlation between EMG activity, occlusal relationships and craniofacial morphology to analyze the effect of muscular activity, as an etiological factor in malocclusion. The purpose of the present investigation is to analyze the effect of EMG activity of temporal and masseter muscles quantitatively in skeletal class III malocclusion. 26 patients (9 to If years old), with class III malocclusion were selected and their EMG activity of temporal and masseter muscles in rest position, centric occlusion, clenching, mastication and swallowing were compared with 20 normal children at the same age range. Then the statistical correlation between 13 cephalometric parameters and EMG activities were analyzed and then the regression analysis was performed and the results were as follows:
1- The mean amplitude of masseter and temporal muscles activity in rest position, centric occlusion, mastication, and clenching in class III samples were greater than normal group (PO.05).
2- The mean duration of masseter and temporal muscles activity in rest position and centric occlusion in class III samples were more than normal group (PO.05).
3- According to regression analysis, a linear correlation was observed between ANB angle and temporal muscle activity in rest and centric occlusion that was not observed in other cases.
The findings of this study showed that difference in temporal muscle activity in class III malocclusion, in comparison with the normal group, is correlated with skeletal morphology of the face, but according to other investigations it is not ture for the masseter muscle.
T. Hoseinzadeh-Nik , A. Malakooti,
Volume 17, Issue 4 (1-2005)
Abstract
Statement of Problem: Craniocervical Posture is a factor in the development and function of Craniofacial Structure. Previous studies of different samples have demonstrated associations between craniocervical posture and craniofacial morphology.
Purpose: This study aimed lo examine whether any significant association is evident or not between craniocervical posture and the occurrence of Class il & Class III skeletal malocclusions.
Materials and Methods: A sample of 76 subjects with Class II & Class III skeletal malocclusion aged 9-i 1 and>18 years were selected. None of them had received orthodontic treatment. Lateral cephalometric radiographs were taken in natural head position (NHP), and craniocervical and craniohorizental angels were traced and determined for analysis of craniocervical posture.
Results: According to the craniocervical posture, most class II skeletal patients have flexed heads and class MI skeletal patients have extended heads, as a result malocclusion in these patients seems to become more severe.With increase in age. class II skeletal patients have more flexed their heads and malocclusion become more severe, while with increase in age in class ill skeletal patients, their heads become extended and once again malocclusion thought lo be more severe. In class II skeletal patients, craniocervical posture has a significant correlation with the vertical growth pattern, but shows little correlation with the horizontal growth pattern. In class 111 skeletal patients, craniocervical posture shows no correlation to any of the vertical & horizontal growth patterns, of course the mean of vertical angles is less in these patients and probably in order to make these relation significant in Class III skeletal patients there is need for more samples, in class II & class III skeletal patients, the amount of Na.prep-point A and pog-Na.prep with craniocervical posture shows a significant correlation.
Conclusion: Consideration of craniocervical posture (in addition to cephalometric angles) lead to making better treatment planning.
T. Hosseinzadeh Nik , M. Habibi , B. Golestan , Hr. Barikani ,
Volume 20, Issue 4 (1-2008)
Abstract
Background and Aim: Chin cup is an orthopedic appliance for treating growing skeletally Cl III patients. The amount of chin forward movement in addition to morphologic changes in bony structure, determines the final profile of treated patients. The aim of this study was to evaluate the amount of morphologic changes of symphysis after chin cup therapy in skeletally Cl III patients.
Materials and Methods: In this clinical trial, twenty eight cephalometries before and after chin cup therapy of 14 skeletally Cl III patients were analyzed. Landmarks introduced by Ricketts were determined to evaluate the symphysis and describe its relation to mandible. َAlso four additional measurements regarding the symphysis individually were evaluated and analyzed. Data were analyzed by paired t and pearson tests with P<0.05 as the level of significance.
Results: The results showed that the height of symphysis increased after treatment (P=0.02), but its depth decreased (P=0.04). The sysmphysis turned down and back.
Conclusion: These findings suggest that in Cl III malocclusions with a prognathic mandible, chin cup therapy creates changes in the horizontal dimension of symphysis morphology, which improves the Cl III profile. If the patient isn't a vertical grower, vertical changes of symphysis would be desirable. In addition, changes in the vertical dimension of the mandible (body and ramus) could be observed as a backward and downward rotation.
Ms. Ahmad Akhondi, A. Khorshidian, J. Chalipa,
Volume 21, Issue 2 (11-2008)
Abstract
Background and Aim: Among different treatments of patients with Class III malocclusion , orthopedic protraction of maxilla has been known as an effective method in mixed dentition period. The aim of this study was to evaluate the cephalometric changes of Cl III patients in mixed dentition period following face mask therapy and slow maxillary expansion.
Materials and Methods: This was a before-after study which was conducted on 10 children in mixed dentition period, who had class III malocclusion and maxillary deficiency according to the Stiener and Mc Namara's analysis. The patients were all treated by protraction face mask and slow maxillary expansion. The cephalometric changes of maxilla , mandible and dental relations during the treatment were analyzed by Paired sample T Test. P<0.05 was considered as the level of significant.
Results: The overjet increasement was 1.7mm. Co. ANS distance improvement was 5.6mm, Ptm.ANS distance increasing was 3mm, and ultimately improvement of Gf.s distance was 1.5mm which were all statistically significant (p<0.05).
Conclusion: Based on the results of this study, face mask therapy with slow maxillary expansion is able to improve the horizotal position of maxilla, in patients with Cl III malocclusion , in mixed dentition period.
Sahar Ghodsi Bushehri, Farzaneh Khajeh, Somayeh Heidari, Shahla Momeni Danaei,
Volume 26, Issue 2 (5-2013)
Abstract
Background and Aims: Skeletal class III malocclusions are considered as one of the most complex and difficult orthodontic problems to diagnose and treat. Facial appearance and occlusion problems make the patients to seek treatment as soon as possible. The purpose of this study was to evaluate the outcomes of early treatment with facemask compared to the patients who had no treatment.
Materials and Methods: For this retrospective study, 38 growing patients (mean age, 8.5 years old) with class III dentoskeletal malocclusion were divided into 2 groups. 23 patients were treated with facemask and 15 patients who did not receive any treatment were assigned as control group. Lateral cephalograms were taken before and after treatment and dentoskeletal changes were estimated. Data were analyzed using Wilcoxon signed ranks test.
Results: The results revealed statistically significant forward displacement of maxillary bone and upper incisors (P<0.001), and downward-backward rotation of mandible in facemask group (P<0.001). Increased lower facial height was seen in both treatment and untreated groups. However, in untreated group some measurements revealed forward displacement of maxillary complex as well.
Conclusion: It seems that in class III patients treating with facemask is a better choice than ChinCap and decision making for early treatment in class III patients should be considered seriously. Moreover, specific attention to the type of patient’s skeletal discrepancy is necessary. In class III patients, facemask might be a better option than other appliances.
Mohsen Shirazi, Armina Mellat, Behzad Salari,
Volume 29, Issue 3 (10-2016)
Abstract
Background and Aims: In the field of orthodontics, gaining comprehensive information around dento-skeletal complex is necessary to choose the best treatment plan for each patient. The aim of this study was to investigate the linear and angular parameters in panoramic radiographs to find a path to correlate transvers to sagittal dimensions.
Materials and Methods: Total number of sixty two, 8-14 years old children who sought for orthodontic therapy were selected (32 skeletal Class III and 30 skeletal Class I). They were exposed to x-ray to obtain the panoramic and lateral views in a controlled condition. Various linear and angular parameters were measured after tracing the landmarks on the panoramic radiograph. Data were obtained and analyzed using T-test. The level of significance was set at 0.05 (P<0.05).
Results: Linear parameters of Co-Co, Go-Go and PTM-PTM were significantly lower in class III patients than class I ones (P=0.04, 0.04, 0.02, respectively). The ramus width value was also lower in class III patients. Angular parameters of Me˄ and N˄ also showed the same results (P<0.001). Go˄ angle was significantly lower in the class I than class III patients (P=0.002, 0.007).
Conclusion: Some traceable linear and angular parameters were found in the panoramic radiographs which had the potential to correlate the transverse with sagittal dimension.
Komeil Rezazadeh, Reza Faraji, Manouchehr Rahmati Kamel,
Volume 37, Issue 0 (3-2024)
Abstract
Background and Aims: Considering the extensive connections of anatomical components in the head and neck region, it is expected that a change in one of the components of this functional unit will have effects on other parts. The aim of this study was to investigate the effect of correction of class III skeletal relationship with orthognathic surgery on the angles between cervical vertebrae.
Materials and Methods: This descriptive-analytical retrospective study was conducted in 1403 at the orthodontic department of Babol Dental School. 30 patients with class III skeletal malformations in the age group of 18 to 48 years who underwent orthognathic surgery (single jaw or double jaw) and had a good quality lateral cephalometric radiography were randomly selected and available based on entry and exit criteria. Dependent variables including 13 parameters in the cranial (angles of SNA, SNB, ANB and Wits App), cervical (the angle between the OPT and CVT lines with each other and with the true perpendicular line) and craniocervical area (the angle of the OPT and CVT lines with the horizontal planes of the head, including the mandibular and palatal plane) of the head and neck were used to evaluate the angles between the cervical vertebrae. The data were analyzed using SPSS22 software and independent t-test, and in case of non-normality, Will-Coxon test was used.
Results: In this study, a total of 30 samples were examined. None of the measured parameters of the cervical area before and after surgery showed a statistically significant change (P<0.05). By comparing the angles between the cervical vertebrae, the PP/CVT angle in the craniocervical region showed statistically significant changes (P=0.024). The values of PP/OPT, MP/OPT, SN/CVT, and MP/CVT angles increased slightly after surgery, but they were not statistically significant (P≥0.05), which showed a relative increase in the tension of the head on the upper part of the cervical spine.
Conclusion: Changing the position of the jaw following orthognathic surgery could cause head extension, but it had no effect on the position of the first 4 cervical vertebrae.
