Showing 14 results for Ii
F. Aghahoseini , M. Shanbadi ,
Volume 13, Issue 2 (5-2000)
Abstract
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.
L. Eslamian ,
Volume 15, Issue 1 (3-2002)
Abstract
Various comparative studies have been conducted to investigate the effect of functional and fixed appliances in treatment of class II skeletal disorders. The aim of this study was to compare Bionator and Edgewise appliances associated with class II elastics in the treatment of class II skeletal patients, without extraction. Lateral cephalograms of 30 patients (16 girls, 14 boys), 10-13 years old, with class II div I maolocclusion, treated with Bionater and Edgewise appliances were investigated before and after treatment. SNA, SNB, ANB, " to SN, IMP A, mandibular and maxillary lengths, upper anterior facial height to lower anterior facial height, overjet and overbite were measured in each group before and after treatment. The results were analyzed by paired t- test. The magnification of linear measurements were calculated. The differences between variables in 2 groups were compared by t-test. There was no significant difference, regarding age and sex. In both groups, increase in SNB, mandibular length, and IMPA and decrease in " to SN, overjet and overbite and upper anterior face height to lower anterior face height after treatment were statistically significant. Comparing 2 groups before and after treatment showed that increase in SNB and decrease of ANB, overjet and overbite were more in Bionator group than fixed group, which were significant. Decrease in upper anterior face height to lower anterior face height, and increase in IMPA and mandibular length were more in Bionater group but the differences were not statistically significant.
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.
S. Yassaei , Mm. Soroush ,
Volume 19, Issue 4 (1-2007)
Abstract
Background and Aim: Unlike other bones of the head and neck, hyoid bone has no bony articulations. It is connected to mandible, cranium and pharynx through muscles and ligaments. During treatment with functional appliance in patients with class II div1 malocclusion, mandible is positioned in inferior and anterior direction. Regarding the relation between hyoid and mandibular bone, alterations of hyoid bone position can be a result of functional appliance therapy. The aim of this study was to evaluate the changes of hyoid bone position following treatment with Farmand functional appliance in patients with class II div 1 malocclusion.
Materials and Methods: In this before-after clinical trial, 28 patients with class II div 1 malocclusion which were under treatment with Farmand functional appliance for 11 months were selected. Facial growth in vertical, normal or horizontal direction was determined by cephalometric measurement. Data were analyzed with Paired-t test to compare the differences of mean values pre and post treatment. Variance analysis was used to compare the three growth patterns. P<0.05 was considered as the limit of significance.
Results: Hyoid bone shifted significantly forward in horizontal dimension (P<0.01) and non-significantly upward in vertical dimension. There was no significant difference among the three studied groups with respect to hyoid bone position alterations in horizontal dimension but significant difference was observed between horizontal and vertical growth pattern in vertical dimension (P<0.05). There was significant correlation between decrease of ANB angle and forward movement of hyoid bone.
Conclusion: Based on the results of this study, treatment with Farmand functional appliance (Fa II) leads to significant alterations in the position and anterior displacement of the hyoid bone.
S. Yassaei , H. Aghili , D. Razeghi ,
Volume 20, Issue 3 (6-2007)
Abstract
Background and Aim: Functional appliances refer to a variety of removable or fixed appliances designed to alter the mandibular position both sagitally and vertically, resulting in orthodontic and orthopedic changes. Despite the long history of functional appliances, there is still much controversy related to their effectiveness and mode of action. The aim of this study was to evaluate dental and skeletal effects of Fa II in patients with class II malocclusion due to mandibular deficiency.
Materials and Methods: In this before-after clinical trial, 35 patients with class II div I malocclusion were selected. These samples were under treatment with Fa II appliance for 11 months. The range of age of females was 10-13 years and males 11-14 years. Combination analysis was used to determine skeletal and dental effects. Paired t-test was used to compare the differences of mean value pre and post treatment. P<0.05 was considered as the level of significance.
Results: There was significant difference between pre and post treatment in respect to posterior and anterior facial height, eruption of upper and lower posterior teeth, eruption of upper anterior teeth, mandibular body length, ANB angle, IMPA and 1 to SN. No significant difference was observed between pre and post treatment regarding facial growth.
Conclusion: Treatment with Fa II functional appliance leads to significant alterations in dental and skeletal elements of craniofacial complex and improvement of dental and jaws relationship.
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.
J. Chalipa, Mh. Hosseini, Mk . Hosseinian Serajelou, A. Khorshidian,
Volume 23, Issue 1 (6-2010)
Abstract
Background and Aims: One of the common human evolutionary anomalies is dental Missing. Evolution of dental system is toward deduction of teeth number. The Missing of third molar is interesting subject for dentists and genetic researches because of its variety in different races. Consideration of bilateral effect of third molar Missing with jaw relation is an important subject. The aim of this study was to evaluate the third molar missing in Cl I and Cl II skeletal (without rotation) and comparison of them together.
Materials and Methods: The patients of the orthodontic department of school of Dentistry (Tehran University of Medical Sciences) were analyzed. About 121 patients had Cl I and 60 patients had ClI jaw relation. This relation identified based on cephalometric lateral radiographic ANB corner angle. Patient who had rotation in maxilla or mandible based on SN-Go Gn angle were excluded. The incidence of third molars agenesis in individual dentition quadrants, upper and lower jaw and right and left side of dentition was examined from panoramic radiography. AChi-square test was used for statistical analysis of data.
Results: Missing of one or more third molar in skeletal Cl I and Cl II was 43% and 33.3%, respectively. Missing of one or more third molar in Cl II was fewer than Cl I, but no statistically significant differences were seen between them.
Conclusion: There was not a direct relationship between jaw relation and third molar Missing.
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.
Allahyar Geramy, Amir Hossein Mirhashemi, Sahar Rafiei Chokami, Ahmadreza Shamshiri,
Volume 28, Issue 3 (10-2015)
Abstract
Background and Aims: Cl II malocclusion is one of the most common abnormalities in human societies and using a simple, affordable and accessible treatment that can be provided by general practitioners or specialists, to prevent future malocclusion complications is vital
. Cl II malocclusion treatment using functional appliances such as twin block and anterior inclined bite plan have less cost, side effects and complications compared to fixed orthodontic or orthosurgery
. Until now, the dentoskeletal changes resulting from the application of twin block and anterior inclined bite plan in patients with Class II malocclusion has not been evaluated. The objective of the present study was to assess the dentoskeletal changes following the use of twin-block functional appliance and inclined anterior bite plan in the patients with class II malocclusion div 1 during mixed dentition.
Materials and Methods: In this retrospective cohort trial, 60 patients with the definitive diagnosis of Class II div. 1 malocclusion having ANB>2 and FMA angel between 20 and 30 and without any previous treatment or syndrome who were treated with twin-block or inclined anterior bite plan appliance were selected and their lateral cephalometries were traced before and after treatment. Selected distance and angular landmarks were measured on the cephalograms with the good reliability (ICC=0.953) and the changes occurred in the landmarks were statistically analyzed using Student t test.
Results: Due to the increased mandibular growth, most of the landmarks experienced significant changes following the treatment with twin-block and inclined bite plan (P<0.05). The appliances corrected Class II malocclusion through improvement of mandibular length and position, maxillary and mandibular skeletal and dental relationships (decreased ANB angle and overjet) and stability of mandibular plan inclination. No significant differences were found between the devices regarding most landmarks changes (P>0.05), however, SNA (P=0.04), overjet (P=0.007) and wits appraisal (P=0.004) changed differently after using the appliances.
Conclusion: Despite with most similarities of both twin-block and anterior inclined bite plan to correct class II div. 1 malocclusion, Due to the advantages of anterior inclined bite plan such as less size, good patient cooperation and simple laboratory preparations the appliance can be used as substitute for complex functional appliances to correct class II div. 1 malocclusion before the growth spurt.
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.
Abdolrahim Davari, Alireza Daneshkazemi, Farnaz Frahat, Fatemeh Kohestani,
Volume 32, Issue 1 (7-2019)
Abstract
Background and Aims: Despite patient’s demand increased for tooth color restorations, the stable bond between dentin and composite is a challenge in dentistry. Dentin protease activation is responsible for dentin-resin bond failure. The aim of this study was to determine the best pretreatment agent to inhibit matrix metalloproteinase and increase resin-dentin bond durability.
Materials and Methods: After collecting 24 intact third molars, the dentin surfaces were exposed immediately under DEJ. After acid etching of dentin rewetting was done with CHX 2%, EDC 0.3 M for 60 and water (control group). Then the adhesive (Single bond, 3M ESPE, USA) and composite (Filtek Z250 XT, 3M ESPE, USA) were applied. 48 sectioned dentinal specimens were prepared. The specimens were divided into 3 groups. Each group was divided into 2 sub groups (n=8). In half of each group, the micro tensile bond strength test was done immediately and another part half 6 months. Then, the specimens were evaluated by stereomicroscope and SEM. Statistical analysis was performed using SPSS23 software, two-way ANOVA and multiple Tukey and T-test comparisons. P<0.05 was considered as a significant level.
Results: There were not significant differences between immediate micro tensile bond strength of CHX, EDC and control groups (P=0.97). However, there was significant differences between CHX, EDC compared with the control group (P≤0.0001). Comparison between the immediate and 6-month bond strengths in each group, only in EDC group, there was no significant after 6 months’ difference (P=0.64).
Conclusion: EDC and CHX t did not have any effect on the immediate microtensile bond strength. After 6 months, EDC prevented bond strength deterioration, but the bond strength was decreased after CHX usage.
