Egyptian Orthodontic Society
Egyptian Orthodontic Journal
1110-435X
2812-5258
55
June 2019
2019
06
01
Effect Of changing various parameters on stress distribution in mini-screws and surrounding alveolar bone: a three dimensional finite element analysis
7
24
EN
Ayman
Sadek
Assistant Research Lecturer of Orthodontics, National Research Center. Egypt
Ibrahim
Negm
Assistant Professor of Orthodontics, Faculty of Dentistry, Ain Shams University, Egypt
Khaled
Aboulazm
Assistant Professor, Department of Orthodontics, School of Dentistry, Pharos University, Alexandria, Egypt
10.21608/eos.2019.76617
Aim: The purpose of the study was to clarify and evaluate the effects of various force magnitudes and mini-screw length, diameter and insertion angle on the stress distribution of the mini-screw and the surrounding bone utilizing a three dimensional finite element analysis. Methods: We created a three dimensional finite element model simulating various clinical situations where mini-screws with different diameters (1.5 and 2 mm), lengths (9, 11 and 13 mm) and insertion angles (45o and 90o) were utilized under various force magnitudes (200 and 250gm). The resultant deformations and stresses from the applied loading were analyzed with a 3D FEM according to maximum values of total deformations and Von Mises stress. Results: The Von Mises stresses in both the mini-screw and the cortical bone in obliquely inserted 1.5 mm diameter screws with 200 gm and 250gm force were higher than those with 2 mm diameter screws. The Von Mises stresses in the spongy bone in both the vertically and obliquely inserted 1.5 and 2 mm diameter screws with 200gm and 250gm force were higher with the 2 mm diameter screws. The maximum compressive stress and equivalent micro-strain in cortical bone was evident with screw dimensions 13mm length and 2mm diameter under an oblique force magnitude of 250 gm. The Von Mises stresses in the spongy bone in obliquely inserted 1.5 and 2 mm diameter screws with 200gm and 250gm force were higher with the 2 mm diameter screws The maximum stress (Von Mises) generated in the miniscrew and cortical bone in all the simulated finite element models was 72.77 and 13.52 MPa respectively. Conclusion: Increase in the mini-screw diameter with both vertical and oblique insertion reduced the deformations and stresses within the mini-screw and cortical bone but increased the deformations and stresses within the spongy bone. Increase in the mini-screw length with vertical insertion had negligible effect. The deformation and stress values within the cortical bone were higher in oblique insertion than vertical insertion with both (200 and 250 gm) force
Stress,Mini-screws,Finite Element Analysis
https://eos.journals.ekb.eg/article_76617.html
https://eos.journals.ekb.eg/article_76617_b8f9738efb89a26c846e5389369689c9.pdf
Egyptian Orthodontic Society
Egyptian Orthodontic Journal
1110-435X
2812-5258
55
June 2019
2019
06
01
Cephalometric features of Angle class III malocclusion with different dentoalveolar compensation (retrospective study)
25
38
EN
Dina
Elfouly
Department of Orthodontics, Faculty of Dentistry, Alexandria University, Egypt
Eiman
Marzouk
Department of Orthodontics, Faculty of Dentistry, Alexandria University, Egypt
Hanan
Ismail
0000 0002 2685 7075
Department of Orthodontics, Faculty of Dentistry, Alexandria University, Egypt
hananaminismail@gmail.com
10.21608/eos.2019.77125
Introduction: This study was to investigate dentoalveolar compensation in untreated skeletal Class III patients. Methods:This retrospective study was conducted on 102 untreated Class III malocclusion patients. They were divided into group 1 (overjet<0mm, n=51) and group 2 (overjet ≥ 0mm, n=51). Twenty-six cephlometric readings were compared between the two groups. Correlation analysis was performed between the overjet with skeletal and dental measurements and Regression analysis was performed to determine the overjet. Results: The results showed a significantly higher SNB, S-N-Pg, gonial angle and L1-NB mm in the negative overjet group. While, the ANB angle, angle of convexity, Wits appraisal, bony chin and U1- A-Pg mm were significantly higher in the positive overjet group. However, no statistically significant difference was found in the rest of the readings. Correlational analyses showed that the overjet has significant negative correlation with SNB, S-N-Pg, L1-Frankfort, gonialangles. On the other hand, it had significant positivecorrelation with ANB angle, angle of convexity, Wits appraisal, bony chin, L1-MP angle and U1-A-Pg mm. Nine regression equations for the overjet were calculated with the highest coeffcient of determination of 0.33. Conclusion: Dentoalveolar compensation was seen in Class III cases with less skeletal discrepancy, lower mandibular prominence, larger bony chin, greater angle of convexity and smaller gonial angle. Moreover, the position of the maxillary and mandibular incisors on the basal bone, rather than their inclination, contributed in dentoalveolar compensation
Class III malocclusion,Dentoalveolar compensation,Overjet
https://eos.journals.ekb.eg/article_77125.html
https://eos.journals.ekb.eg/article_77125_7aa13329e81b500f2cfb809531bdc90f.pdf
Egyptian Orthodontic Society
Egyptian Orthodontic Journal
1110-435X
2812-5258
55
June 2019
2019
06
01
Different types of malocclusion and oral habits in Sharja and Ajman Emirates
39
52
EN
Hanaa
Elattar
Department of Orthodontics, Faculty of Dentistry, Suez Canal University, Egypt -
Faculty of Dentistry, Umm Al-Qura University, Saudi Arabia
Omnia
Elhiny
Department of Orthodontics and Pediatric Dentistry, National Research Centre, Egypt
May
El Janahi
Faculty of Dentistry, Gulf Medical University, Ajman, UAE
10.21608/eos.2019.77126
Aim: to determine the prevalence of malocclusion among adults attending Dental Centers in Ajman and Sharjah, as well as the association of gender, ethnicity, and prevalent oral habits with the types of malocclusion. Material and Methods: The study was conducted on 300 patients with age range 18-30 years. Intraoral dental and Orthodontic classification was performed alongside a questionnaire. Patients’ occlusions were classified based on Angle’s Classification. Results: Among the sample group, it was found that Class I malocclusion was the most prevalent malocclusion with 74% , Class II division 1 was 12% and Class II division 2 was 11% and the least was Class III with 3% with significant difference between males and females. For different ethnic groups included in the study the same pattern of prevalence applied (Class I followed by Class II, Class III came last) except for Caucasians and Far Eastern, where Class II division 2 surpassed division 1 with a significant difference between all Classes of malocclusion except for Class I. As for oral habits, nail biting was the most prevalent oral habit showing 20.7%, followed by teeth grinding 11%, thumb sucking 10%. Tongue Thrust was the least prevalent habit with a significantly higher prevalence in Class II malocclusion of the studied sample. CONCLUSION: Class I malocclusion was the most prevalent malocclusion, followed by Class II division 1, Class II division 2, and the least was Class III. All ethnic groups showed the same pattern of distribution except for Caucasians, Far Eastern, and South Asian. The pattern of distribution was the same for both males and females; however, a difference in the percentage existed between genders. The most prevalent oral habit was nail biting. All oral habits were not related to different types of malocclusions except for tongue thrust (higher prevalence in Class II Malocclusion). This study is a base for further Arab and Middle Eastern studies.
malocclusion,Oral habits,Ethnic groups,Prevalence of malocclusion
https://eos.journals.ekb.eg/article_77126.html
https://eos.journals.ekb.eg/article_77126_d1da7505f3c98164ad02d33c3183432f.pdf
Egyptian Orthodontic Society
Egyptian Orthodontic Journal
1110-435X
2812-5258
55
June 2019
2019
06
01
Morphological features of dentition associated with unilateral palatally impacted canine using cone beam computed tomograpahy: an etiological study
53
65
EN
Omar
Okasha
Department of Orthodontics, Faculty of Dentistry, Alexandria University, Egypt
Essam
Abdallah
Department of Orthodontics, Faculty of Dentistry, Alexandria University, Egypt
Tarek
Yousry
Department of Orthodontics, Faculty of Dentistry, Alexandria University, Egypt
10.21608/eos.2019.77127
Introduction: the aim of this study is to determine the morphological features of dentition associated with unilateral palatally impacted maxillary canine and to predict of the possible local risk factors causing palatal impaction of the maxillary canine. Materials and Methods: 45 cone beam computer tomography were collected of patients diagnosed with unilateral palatally impacted canines 11 males and 34 females the mean age was 20.38 ± 4.37. The maxilla was divided into two for a split mouth design.The following parameters were obtained: The mesiodistal width of each tooth, the crown /root ratio of each tooth, and the volume of the impacted canine compared to the contralateral normally erupting canine, angulation and morphology of the root, Interpremolar and intermolar width of the upper arch and the arch perimeter.The measures were compared between the 2 sides. The data obtained in this study was subjected to Kolmogorov-Smirnov test, McNemar test and Paired t-test at P ≤0.05. Results: The results showed larger canine volume, narrower interpremolar width and increased crown root ratio of the laterals and canines on the impacted side. There was no statistically significant difference between two sides in the rest of the measurements. Conclusion: Narrower interpremolar width, increased canine volume, shorter root of lateral incisor and increased length of canine crown are contributing factors for impaction of the canine.
Impacted canines,cone beam,Canine volume,Maxillary dentition morphology
https://eos.journals.ekb.eg/article_77127.html
https://eos.journals.ekb.eg/article_77127_9c8a70d2f0d395b6488cbb0d7c299f97.pdf
Egyptian Orthodontic Society
Egyptian Orthodontic Journal
1110-435X
2812-5258
55
June 2019
2019
06
01
Comparison between the effectiveness of two sealants in prevention of enamel white spot lesions: in vitro study
67
88
EN
Isis
Afifi
Department of Orthodontics, Faculty of Dentistry, Alexandria University, Egypt
Mohamed
Mowafy
Department of Orthodontics, Faculty of Dentistry, Alexandria University, Egypt
mo_mowafy@hotmail.com
Nazla
Tamish
Department of Orthodontics, Faculty of Dentistry, Alexandria University, Egypt
10.21608/eos.2019.77128
Objectives: This study was done to compare between the effectiveness of using highly filled and lightly filled sealants in preventing demineralization and resisting acid and abrasion through assessing enamel color change differences and sealant retention after induced challenges. Methods: 100 human premolars were collected and allocated into 2 groups. The buccal surfaces of the 1st group were sealed with a 38% filled sealant (Opal®SealTM) and the 2nd group with an 18 % filled one (PRO SEAL®). Both groups were exposed to acidic and abrasive challenges. Enamel color changes were recorded spectrophotometrically at baseline (T0), after sealant application (T1), after first exposure to acidic challenge (T2), and after second exposure to acidic challenge and simulated toothbrushing (T3). Standardized photographs were taken for each tooth under ultraviolet light at baseline and at (T3). Teeth images were analyzed using computer software to estimate sealant coverage and fluorescence loss. Results: The best protection was seen in the Opal seal group after the 1st acidic challenge (p=0.000) when compared with PRO SEAL. Greater sealant material loss (68.78% ± 15.54) and fluorescence loss (82.46% ± 11.04) were seen in the PRO SEAL group (p=0.000). Both sealants changed the original enamel color similarly and exceeded the clinically detectable threshold (ΔE=3.7). Conclusion: Based on the results of this study; increasing the filler content strengthens the sealant, therefore, offering more protection against white spot lesions. Both sealants degrade with increasing the challenges. Both sealants change the initial enamel color similarly.
White spot lesions,Orthodontic sealants,Filled sealants,Color change,demineralization,Spectrophotometer
https://eos.journals.ekb.eg/article_77128.html
https://eos.journals.ekb.eg/article_77128_b9da0f648596221545b0829be0426cfc.pdf