FMA Angle Research Articles

Cephalometric variation of vertical dimension in patients treated with hyrax-type and McNamara-type rapid palatal expander. Study on latero-lateral teleradiography

To analyze changes in the vertical dimension of the lower third of the face studied on teleradiograph in L-L following rapid palatal expansion achieved by four-band Hyrax-type rapid palatal expander (RPE) and by acrylic-bonded McNamara RPE to identify the most appropriate therapeutic choice based on the patient's facial growth pattern. 30 patients were selected, of whom 20 (9 males and 11 females with a mean age of 8.285 ± 1.216) were treated using McNamara RPE (Group D), and 10 (6 males and 4 females with a mean age of 8.562 ± 1.152) were treated with Hyrax RPE (Group B), for an average treatment time T0-T1 of 0.96 ± 0.501 years. According to Tweed and Ricketts, Cephalometric tracings obtained from lateral cephalograms at T0 and T1 were analyzed to study changes in the vertical dimension of the lower third of the face. For this purpose, 6 cephalometric landmarks were considered: convexity (distance of point A to the NPg plane), Ricketts’ total face height (angle between the NBa plane and Xi-Pm plane), lower face height (angle between the ANS and Xi-Pm planes), facial axis (angle between the NaBa plane and PtGn plane), ANB angle, and FMA angle. No statistically significant differences were found between the measurements at T0 and T1 for any of the 6 cephalometric measurements considered, neither within the single groups nor when comparing the two. However, a greater increasing trend was found for some variables between the two groups, such as Ricketts' total facial height, lower facial height, and FMA angle, although not statistically significant. Hyrax and McNamara's RPEs have provided minimal changes in the vertical component during palatal expansion treatment, thus demonstrating their ability to preserve the vertical dimension of the face. Therefore, there are no contraindications for using either appliance for patients with dolichofacial growth patterns.

Comparative evaluation of facial divine proportions in males and females with average growth pattern

Facial beauty of an individual depends on proportion and its relationship to various facial parts which varies in each individual. The values of measured proportion in beautiful faces are likely to approximate divine proportion and may show variation with ethinicity, sex, growth pattern. Hence, aim of the study was to evaluate and compare vertical and horizontal parameters of facial divine proportions in male and female subjects with average growth pattern. 30 subjects (18-30 yrs age) with average growth pattern (based on cephalometric measurements FMA, Yaxis, GoGn-SN and facial axis angle) were divided into two groups as Group I (Male subjects, n=15) ; Group II (female subjects, n=15). Standardized frontal facial photographs of all the subjects were obtained. Nine vertical and four horizontal parameters were measured on all the facial photographs using IC Measure software and were used to evaluate horizontal and vertical facial proportions and then compared to divine proportions considering 1.618 as 100%. Horizontal and Vertical facial proportion in males were higher than females. Group I showed that three of seven vertical facial proportions were close to divine proportion (1.618) whereas only one vertical facial proportion in Group II were close to divine proportions. Horizontal facial proportions in both the groups deviated more from divine proportion (1.618).There was difference between males and females for the vertical and horizontal facial proportions with values being larger in males. This should be considered as an accessory guideline in planning orthodontic or orthognathic treatment.

A Comparison of Smartphone-assisted and Computer Software Assisted Tracing with the Conventional Manual Method

Introduction In view of the increased use of computers and mobile technologies in orthodontics, there is a need for evaluating the accuracy of commercially available cephalometric software. Aim This study compares the accuracies of computer-assisted tracing, smartphone tracing with the manual method of tracing in the pre-treatment lateral cephalograms of the orthodontic patients. Materials and Methods A total of 100 cephalograms, both digital and hard copies, were collected from the records available in the department archives. Hard and soft copies were used for obtaining values of 17 parameters for comparison between different groups. i.e (Manual, NemoCeph®, AutoCeph®, CephNinja®, OneCeph®) Results No statistical significance between groups for SNA, SNB, ANB, FMA, SN-GoGn, U1-NA Angular,linear, L1-NB Angular, linear, IMPA and interincisal angle (p=0.798, 0.583, 0.895, 0.059, 0.140, 0.680, 0.161, 0.327, 0.906, 0.940, 0.789). A significant difference was seen for parameters Eff-Mx,Mn lengths and differential, L1-Occlusal plane, WITS, NLA.(p=0.000, 0.004, 0.018, 0.004, 0.025). Suggesting the possibility of use of software for tracing instead of manual method. Conclusions All the software (NemoCeph®, AutoCeph®, CephNinja®, OneCeph®)as well as applications performed satisfactorily and these can be used instead of manual tracing.

Stability of class II correction with the Austro Repositioner associated with multi-brackets fixed appliances in dolichofacial patients

BackgroundThe purposes of the present study were to evaluate the changes produced by the Austro Repositioner, and to assess the stability of Class II malocclusion treatment with the Austro Repositioner associated with fixed appliances and its capacity to control the vertical dimension in dolichofacial patients.MethodsA group of patients with Class II malocclusion due to mandibular retrognathism and a dolichofacial growth pattern treated with the Austro Repositioner combined with fixed appliances were compared to a matched untreated control group of subjects with Class II malocclusion. Evaluations were made on the basis of lateral cephalograms taken at T1 (initial records), T2 (end of treatment), and T3 (1 year after treatment). Statistical comparisons were performed with paired- and two-sample t tests.ResultsThe experimental (treated) group comprised 30 patients, 14 boys and 16 girls, and the control group comprised 30 subjects (15 boys and 15 girls) with similar ages at T1, T2 and T3.In the treated group, a significant decrease in the ANB angle was found (− 3.79 ± 1.46; p < 0.001). No significant differences were found in the maxillary skeletal measurements. In contrast, the SNB angle showed a significant increase of 3.77 ± 1.49 in the treated group compared with a nonsignificant increase of 0.77 ± 1.55 in the control group (p = 0.002). Vertical changes showed a significant decrease in the FMA angle (− 3.36 ± 1.62), while the lower anterior facial height distance and the overbite increased significantly in the treated group, reflecting a change in vertical dimensions after treatment. No significant changes were observed in either the treated or control group during the one-year posttreatment period; thus, the treatment results remained stable.ConclusionsThe Austro Repositioner combined with fixed appliances could be considered an optimal treatment modality in Class II dolichofacial patients.

Evaluation of Cervico-vertebral Dimensions and Cranio-cervical Angulations in Adults with Different Vertical Growth Patterns: A Cross-sectional Cephalometric Study

Introduction: The measurement of cervical vertebrae is a valuable diagnostic aid since it provides data on skeletal maturity and potential for growth. Research suggests the existence of a relationship between dentofacial characteristics and craniocervical morphology and posture. This relationship can provide insights into the development and treatment of malocclusions, particularly malocclusions in the vertical dimension. Aim: To compare cervico-vertebral dimensions, morphology, and cranio-cervical postures in subjects with different skeletal growth patterns such as average, horizontal and vertical. Materials and Methods: The study was cross-sectional in design and was conducted for a period of two years between January 2014 and December 2016 at KLE Society’s Institute of Dental Science and Research, Bengaluru, Karnataka, India. A total of 102 lateral cephalograms were taken for the study and classified into three groups according to Frankfurt Mandibular Plane Angle (FMA angle) and Jarabak ratio as Horizontal (HR), Vertical (VR), and Average (AV) groups. Each group comprised 34 subjects (17 males, 17 females). A total of 28 morphological parameters of C3, C4, and C5 in the lateral cephalogram were measured and analysed. Each lateral cephalogram was scanned with a Konica Minolta Bighub Laser printer, and the area measurement was made with IMAGE J software to measure the area of cervical vertebrae. Oneway Analysis of Variance (ANOVA) was used to compare the various parameters between the three groups, and pair-wise comparisons were done using the Least Significant Difference (LSD) test. Student's t-test was done to assess the differences between males and females. A p-value less than 0.05 was considered statistically significant. Results: The mean chronological age of subjects was 21.2±3.14 years for the HR group, 21.3±3.78 years for the VR group, and 21±3.76 years for the AV group. There was a statistically significant difference between the three groups in the measurements of the anterior body height of C3 (ABHC3) (p=0.023), posterior Body Height of C3 (PBHC3) (p=0.007), vertical measurements of C3 (H3) (p=0.010) and (W3) (p=0.013), anterior body height of C4 (ABHC4) (p=0.010), Posterior Body Height of C4 (PBHC4) (p=0.005); H4 (p=0.002); Ratio of H4 and W4 (H4/W4) (p=0.048); area of the third cervical vertebrae (C3) (p=0.039) and area C4 (p=0.024). For cranio-cervical angulation, there were statistically significant differences found for the angle between the Nasion Sella Line (NSL) and the tangent to the Odontoid Process (NSL/OPT) (p&lt;0.001), where the VR group had significantly larger values than the HR and AV groups. There was no significant difference found in fusion anomalies of cervical vertebrae among all three (HR, VR, and AV) groups. Conclusion: The study found that individuals with a horizontal growth pattern tend to have larger cervical vertebral dimensions compared to average and vertical growers. Individuals with a vertical growth pattern exhibited a large cranio-cervical angulation. Overall, males had larger cervical vertebral dimensions compared to females. The studied population did not exhibit any fusion anomalies.

Cephalometric Determination of the Vertical Dimension of Occlusion: Clinical Study

The following is a retrospective descriptive cross-sectional stud aimed at determining the vertical cephalometric standards of a Moroccan population. The values found will be used to orient the choice of the VDO during complex prosthetic rehabilitations where all dental references are absent. The study was conducted on 80 teleradiographies of subjects consulting the ODF department of the CCTD Casablanca with a skeletal class 1 dental occlusion in the absence of any previous or current orthodontic treatment. After performing the cephalometric tracings, we correlated the VDO with 7 angular measurements: ENA-Xi-Pm, GoGn/SN, Occ/SN, Occ/Fr, SGn/Fr, FMA, GoGn/GoENA. Our study led us to the following results: • For the ENA-Xi-Pm angle, we found a mean value of 47.9. • The GoGn/SN angle averaged 38.3°, it varied in 37.29.° • For the Occ/SN angle, it was found that the average value was 21.2° for the whole sample. • The Occ/Fr angle was on average 9.9.° • The SGn/Fr angle averaged 60° in the Moroccan population. • The measurement of the FMA angle showed an average of 27. • Finally, for the GoGn/GoENA angle, we found a mean value of 50. The comparison of our results with those of studies conducted on different populations showed significant differences. This can be explained by the tendency to hyperdivergence in the Moroccan population, hence the interest in using the mean values specific to each population. The comparison of the global means with the means of each group showed that the angular values in hyperdivergent cases are significantly higher than the global values and the angular values in hypodivergent cases are significantly lower than the global values, and for the normodivergent cases, we found a significant difference only for the values of the FMA angle which is lower than the global value of the sample. And thus, the determination of the VDO using cephalometric analysis represents one of the best methods to correctly restore the occlusal environment in a complex prosthetic project, given that the restauration is based on cephalometric standards of the corresponding population.

Accuracy and clinical validity of automated cephalometric analysis using convolutional neural networks.

This study aimed to assess the error range of cephalometric measurements based on the landmarks detected using cascaded CNNs and determine how horizontal and vertical positional errors of individual landmarks affect lateral cephalometric measurements. In total, 120 lateral cephalograms were obtained consecutively from patients (mean age, 32.5 ± 11.6) who visited the Asan Medical Center, Seoul, Korea, for orthodontic treatment between 2019 and 2021. An automated lateral cephalometric analysis model previously developed from a nationwide multi-centre database was used to digitize the lateral cephalograms. The horizontal and vertical landmark position error attributable to the AI model was defined as the distance between the landmark identified by the human and that identified by the AI model on the x- and y-axes. The differences between the cephalometric measurements based on the landmarks identified by the AI model vs those identified by the human examiner were assessed. The association between the lateral cephalometric measurements and the positioning errors in the landmarks comprising the cephalometric measurement was assessed. The mean difference in the angular and linear measurements based on AI vs human landmark localization was .99 ± 1.05°, and .80 ± .82 mm, respectively. Significant differences between the measurements derived from AI-based and human localization were observed for all cephalometric variables except SNA, pog-Nperp, facial angle, SN-GoGn, FMA, Bjork sum, U1-SN, U1-FH, IMPA, L1-NB (angular) and interincisal angle. The errors in landmark positions, especially those that define reference planes, may significantly affect cephalometric measurements. The possibility of errors generated by automated lateral cephalometric analysis systems should be considered when using such systems for orthodontic diagnoses.

Comparative Evaluation of Cranial Base Length and Flexure on Facial Parameters in Hypodivergent, Normodivergent and Hyperdivergent Patients: A Retrospective Cephalometric Study.

The aim of the study was to assess the influence of cranial base length (CBL) and Flexure on facial parameters in Hypodivergent, Normodivergent, and Hyperdivergent patients. Around 60 standardized cephalograms were divided into Hypodivergent, Normodivergent, and Hyperdivergent groups (20 each) based on the FMA angle. The CBL, cranial flexure (CF), and various facial parameters were measured for each case. The results were analyzed for the correlation between Cranial and facial parameters in each of the three study groups. Comparison and Pairwise Comparison of variables between study groups were done using ANOVA and Tukey's post hoc Test. Cranial base length, mandibular body length, LAFH, N-Me-Go angle (p-value <0.001), and Jarabak's ratio were found to be significantly different between the groups. Pearson's Correlation showed that most of the facial parameters had a significant correlation with CBL in Hypodivergent groups. The CBL is more closely related to facial parameters in vertical dysplasia individuals than CF. The CBL is positively correlated to facial variables, especially in Hypodivergent individuals. The N-Me-Go Angle introduced in the study was significantly different in all three vertical facial types studied; hence, it cannot be used as a valuable diagnostic tool. Changes in the length and flexure of the cranial base influence the anteroposterior position of jaw bases. The influence of the cranial base on the development of vertical dysplasias is not studied much, hence the present study aims at resolving this lacuna in literature.

Vertical effects of distalization protocol with Clear aligners in Class II patients: a prospective study.

The aim of the present prospective study was to detect the effects on vertical dentoskeletal dimension produced by molar distalization with Clear Aligners in a group of subjects with Class II malocclusion. The Clear Aligners Group (CAG) comprised 20 patients (13 females, seven males) with a mean age of 17.2±3.2 years. The same standardized protocol of sequential distalization was applied in all subjects. For each patient lateral cephalograms have been analyzed before treatment (T1) and at the end of the therapy (T2). At the end of treatment, clear aligners were effective in the correction of Class II dental relationship with the correction of the overjet (-1.3 mm). The treated group showed statistically significant reduction in FMA angle (-1.3°) associated with a counterclockwise rotation of the occlusal plane (POccl^PF -3.1°; SN^POccl -4.2°) and a slight intrusion of maxillary first molars to palatal plane (-0.9 mm). Finally, statistically significant differences were detected in anterior facial height (N-Me) and in the ArGo^GoMe angle (-1.2 mm and -3.4°, respectively). Upper molar distalization with clear aligners represents a valid alternative to non-extraction treatment of Class II malocclusion, reducing the extrusion of maxillary first molars and improving the control of the occlusal plane and of the vertical dimension.

Distal Femoral Valgus Resection Angle in Conventional Total Knee Arthroplasty - a CT Scanogram Study.

In conventional total knee arthroplasty (TKA), the distal femur valgus resection angle (DFVA) is decided either by measuring the specific resection angle for each patient on preoperative anteroposterior hip-knee-ankle (HKA) weight-bearing radiograph or using a fixed resection angle of five to seven degrees, when such facilities are not available. This study aims to measure the DVFA in TKA patients using preoperative HKA non-weight-bearing computerized tomography (CT) scanogram scout films and determine its relation with preoperative coronal plane lower-limb deformities. In this retrospective radiological study, various measurements were performed on bilateral, preoperative hip-knee-ankle CT scanograms of 73 knee osteoarthritis patients who had presented for total knee replacement surgery using a standard protocol. The angle between the femoral anatomical axis and femoral mechanical axis was measured as the femoral mechanical anatomical angle (FMAA), which corresponds to the surgical DFVA. The angle between the femoral and tibial mechanical axes was measured as mechanical femorotibial angle (MFTA). The correlation between FMAA and MFTA was studied. The mean FMAA for the study group was 6.45° (range 3° to 11°, SD 1.17°). The MFTA for the study group ranged from 24° varus to 14° valgus. The alignment was valgus in 14.4% (n=21), varus in 84.2% (n=123), and "0 degrees" in 1.3% (n=2). With valgus coronal alignment taken as positive and varus as negative, the Pearson's correlation coefficient for MFTA with FMAA was r = -0.5183 (p<0.001), indicating that valgus knees tended to have a smaller FMA angle and varus knees tended to have a larger FMA angle. In the non-availability of individualized measurements, in primary TKA, we recommend setting DFVA as five degrees for valgus deformities, six degrees for mild/moderate varus deformities (MFTA <15°) and seven degrees for severe varus deformities (MFTA > 15°).

The Interaction of Craniofacial Morphology and Body Mass Index in Obstructive Sleep Apnea.

Aim: This study sets out to explore the relationship between craniofacial morphology and obstructive sleep apnea (OSA) severity, assessing the relative contribution of obesity, calculated using BMI. Methods: A sample of 30 adult patients (20 males; 10 females), mean age = 54(±76) years, with a polysomnography-confirmed diagnosis of OSA, i.e., with an apnea-hypopnea index (AHI) of over 5 events/h, was recruited and underwent cephalometric evaluation. Sleep parameters, namely AHI, AHI supine, oxygen desaturation index (ODI), and mean oxygen saturation [Mean SaO2%], were assessed. Correlation analysis between 13 cephalometric features and AHI was performed using a Pearson test. The sample was split into three groups based on AHI score (mild = 10 < AHI < 15; moderate = 15 < AHI < 30; severe = AHI > 30), and ANOVA was performed to compare the means of cephalometric features. In addition, the sample was split into two groups according to BMI (normal weight = BMI < 25; overweight = BMI > 25). Correlation analysis between cephalometric features and AHI was performed for each group using a Pearson test. Results: The average polysomnographic values were AHI = 29.08(±16); AHI supine = 43.45(±21); ODI = 23.98(±21); mean SaO2(%) = 93.12(±2). Posterior facial height (PFH) was significantly lower in the severe OSA group than in patients with moderate OSA (p = 0.05). In the normal-weight group, negative correlations of the PFH and SNA angle with AHI (r = −0.36; r = −0.25, respectively), and positive correlations of the FMA angle and MP-H distance with AHI (r = 0.29; r = 0.20, respectively), were found. In the overweight group, negative correlations of AO-BO distance, SPAS (upper posterior airway space) and PAS (posterior airway space) with AHI (r = −0.30; r = −0.28; r = −0.24, respectively), and positive correlations of AFH (anterior facial height) and the FMA angle with AHI (r = 0.32; r = 0.25, respectively), emerged. Conclusions: PFH seems to be related to the aggravation of OSA. In normal-weight subjects, hard tissue-related factors have a greater impact on OSA severity, whereas in overweight subjects, the impact of fat tissue is greater.

Stability of Class II Malocclusion Treatment with the Austro Repositioner Followed by Fixed Appliances in Brachyfacial Patients.

One of the goals of functional-appliance devices is to modify the vertical growth pattern, solving several kinds of malocclusion. This study aimed to evaluate Class II malocclusion treatment’s stability with Austro Repositioner, followed by fixed appliances, and assess its capacity to modify vertical dimensions in brachyfacial patients. A test group of 30 patients (16 boys and 14 girls, mean 11.9 years old) with Class II malocclusion due to mandibular retrognathism and brachyfacial pattern treated with Austro Repositioner and fixed appliance were compared to a matched untreated Class II control group of 30 patients (17 boys and 13 girls, mean age 11.7 years old). Lateral cephalograms were taken at T1 (initial records), T2 (end of treatment), and T3 (one year after treatment). Statistical comparisons were performed with a paired-sample t-test and two-sample t-tests. Significant improvements in the skeletal Class II relationship were observed in the treated group. The ANB angle decreased (4.75°), the SNB angle increased (3.92°), and the total mandibular length (Co-Pg) increased (8.18 mm) (p < 0.001). Vertical dimensions were also significantly modified, the FMA angle increased (3.94°), LAFH-distance increased (3.15 mm), and overbite decreased (3.35 mm). These changes remained stable one year after treatment. The Austro Repositioner was adequate for treating the skeletal Class II malocclusion resulting from the mandible retrusion in brachyfacial patients.

CBCT Evaluation of Condylar Changes in Class II Hyperdivergent Adult Patients Following Posterior Maxillary Intrusion Using Miniscrews/Miniplates—A Prospective Study

Aim &amp; Objectives: To evaluate using CBCT, the condylar changes taking place in retrognathic, hyperdivergent Class II adult patients following maxillary intrusion using miniscrew assembly. Materials and methods: In this prospective study design, 20 class II div I high angle cases in the age group of 20-25 years with Class II molar and canine relationship; Overjet &gt; 5mm; ANB angle &gt; 4°; FMA angle &gt;25°; SNGoGn &gt; 35°; Jaraback ratio&lt; 60° and Lower Gonial angle&gt;75° were taken. Each patient had a miniscrew assembly in the maxilla through which intrusive force was applied to the maxilla. Two additional miniscrews were placed between the first mandibular molars and second premolars to prevent extrusion of lower molars. CBCT images were taken at the beginning of the treatment (T1) and at the end of 6-9 months of molar intrusion (T2). Statistical analysis was carried out using student T- test. Results: Prior to treatment, the patients showed significant mandibular retrusion associated with increased maxillary posterior heights. Following maxillary intrusion with miniscrew assembly, CBCT evaluation revealed that the distance from the centre of condyle to the posterior border of the external auditory meatus was 19.2±1.67 mm on right side and 18.1±1.54mm on left side in T1 which increased to 19.6±1.45mm on right side and 18.5±1.36mm on left side in T2. The average forward displacement of condyle was .5mm which was statistically significant. The distance from the centre of condyle to superior border of external acoustic meatus was 3.1±1.7 mm on right side and 3.5 ±1.8 mm on left side in T 1 which increased to 3.8±1.9 mm on right side and 4.1 ±1.3mm on left side in T 2. The average downward displacement was .7mm which was statistically significant. Conclusion: Significant Maxillary intrusion can be achieved using miniscrews/ miniplate in adult hyperdivergent skeletal class II patients.

Phenotyping the knee in young non-osteoarthritic knees shows a wide distribution of femoral and tibial coronal alignment.

There is a lack of knowledge about the joint line orientation of the femur and tibia in non-osteoarthritic knees. The primary purpose of the present study was to evaluate the orientation of the joint lines in native non-osteoarthritic knees using 3D-reconstructed CT scans. The secondary purpose was to identify knee phenotypes to combine the information of the femoral and tibial alignment. A total of 308 non-osteoarthritic knees of 160 patients (male to female ratio = 102:58, mean age ± standard deviation 30 ± 7years (16-44years) were retrospectively included from our registry. All patients received CT of the knee according to the Imperial Knee Protocol. The orientation of the femoral and tibial joint line was measured in relation to their mechanical axis (femoral mechanical angle, FMA, and tibial mechanical angle, TMA) using a commercially planning software (KneePLAN 3D, Symbios, Yverdon les Bains, Switzerland). The values of FMA and TMA were compared between males and females. Descriptive statistics, such as means, ranges, and measures of variance (e.g. standard deviations), were presented. Based on these results, phenotypes were introduced for the femur and tibia. These phenotypes, based on FMA and TMA values, consist of a mean value and cover a range of ±1.5° from this mean (3° increments). The distribution of femoral and tibial phenotypes, and their combinations (knee phenotypes) were calculated for the total group and for both genders. The overall mean FMA ± standard deviation (SD) was 93.4° ± 2.0° and values ranged from 87.9° varus to 100° valgus. The overall mean TMA ± SD was 87.2° ± 2.4° with a range of 81.3° varus to 94.6° valgus. FMA and TMA showed significant gender differences (p < 0.01). Females showed more valgus alignment than males. The most common femoral phenotype was neutral in both genders. The most common tibial phenotype was neutral in the male knees (62.8%) and valgus (41.6%) in the female knees. In males, the most frequent combination (knee phenotype) was a neutral phenotype in the femur and a neutral phenotype in the tibia (25.6%). In females, it was a neutral femoral phenotype and a valgus tibial phenotype (28.3%). 3D-reconstructed CT scans confirmed the great variability of the joint line orientation in non-osteoarthritic knees. The introduced femoral and tibial phenotypes enable the evaluation of the femoral and tibial alignment together (knee phenotypes). The variability of knee phenotypes found in this young non-osteoarthritic population clearly shows the need for a more individualized approach in TKA. III.

Relationship between masseter muscle thickness and maxillofacial morphology in pre-orthodontic treatment patients

This study investigated the relationship between masseter muscle thickness and cephalometric facial parameters in pre-orthodontic treatment patients. Participants were grouped according to their vertical facial patterns into low, normal, and high angle facial patterns using standardised lateral cephalometric radiograph. Associations between the masseter muscle thickness (measured using ultrasonography) and different vertical facial patterns were analysed. Masseter muscle thickness in low angle subjects were significantly higher than the normal and high angle cases during both relaxation and contraction phases (P<0.001). Masseter muscle thickness correlated positively with Jarabak ratio and ramus thickness (R1/R2) during both phases, and negatively with LAFH, FMA, MMPA and gonial angle.

Comparison between Classic Twin-block and a Modified Clear Twin-block in Class II, Division 1 Malocclusions: A Randomized Clinical Trial

The aim of this study was to compare dentoskeletal effects and patient's satisfaction with a modified twin-block (clear twin-block) and classic twin-block. A total of 62 patients with skeletal class II malocclusion contributing to mandibular retrognathism with a minimum of 4 mm overjet, the FMA angle between 20 to 25 degree and being in stage 2 to 3 of cervical vertebral maturation participated in this study. Subjects were randomized in 1:1 ratio to classic and clear twin-block. Lateral cephalograms were taken at two stages-Pre- and post-treatment (when the overjet reduced to 1 to 0 mm). All the measurements were done with Dolphin software version 10.5. Four months after the start of the treatment the patients were asked to fill the questioners regarding their compliance from the appliances. Both classic and clear twin-block groups showed mandibular advancement without statistically significant difference between them. However, SNB angle increased slightly more in clear group than the classic one. "Headgear effect" is not statistically noticeable in both groups. However, SNA angle decreased slightly more in classic group. Increased in lower incisors proclination was happening in both groups, but in a clear group, this increase was significantly less. Overbite reduction could be seen in both groups with significantly more reduction in the classic group. Increase in lower incisors proclination was less in clear group than the classic one. Overbite reduction was more in the classic group than the classic one. Clear twin-block is more beneficial in skeletal class II patients with proclined lower incisors and vertical growth pattern.

Does muscular activity related to vertical facial divergence influence the time needed for orthodontic extrusion of palatally impacted maxillary canines? A retrospective study.

BackgroundThe aim of the present study was to evaluate if the different muscular activity correlated to different degrees of facial divergence has an effect on the time needed to extrude a palatally impacted maxillary canine.Material and MethodsTwenty-six patients were retrospectively selected, all treated with a specific cantilever appliance that allows extrusion of the impacted canine applying a physiologic amount of force below 0.6 N in a predictable way. For all the patients, pre-treatment cephalometric tracings were used to evaluate facial divergence through the FMA angle, the angle between the maxillary and mandibular plane, and the angles between the occlusal plane and either the maxillary and mandibular plane. Linear bivariate regression was calculated to evaluate if facial divergence can predict the time needed for canine extrusion.ResultsThe linear regression model was not able to predict extrusion time from variables explaining the facial divergence.ConclusionsPalatally impacted maxillary canines can be treated with the application of physiologic extrusion force regardless of patients’ facial divergence and muscular activity. Key words:Impacted canines, cantilever, facial divergence, muscular activity.

Study Regarding the Applications of Imaging Technology in Cranial Base Morphology in Angle Class II Division 1 and 2 Malocclusions

The aim of the research is to investigate the characteristics of cranial base morphology in class II division 1 and class II division 2 malocclusions. The study group consisted of 40 patients aged 11 years treated at the Orthodontic Department of �Carol Davila� University. Both gender and both malocclusion types were equally represented. Lateral cephalograms were traced and 22 linear and angular cephalometric parameters were calculated: four parameters for the cranial base (N-S-Ba, N-Op-Ba angles, N-S, S-Ba lengths) and 18 parameters for the maxillofacial complex Nsa-Nsp, Go-Gn, Kdl-Go, S-Nsp, N-Nsa, Nsa-Gn, N-Gn, Nsp-Go, SNA angle, ANB angle, SN � NsaNsp angle, SN-GoGn angle, N-Nsa-Gn angle, S-Nsp-Go angle, N-Nsa-Pg angle, gonial angle, FMA angle, NsaNsp � GoGn. Statistical significant differences between cranial base parameters in the two malocclusions groups were depicted, in particular for feminine gender. Regardless of gender, the sphenoidal angle values were mainly increased in both malocclusion groups, when compared to normal population values. The S-Ba lengths were decreased in both malocclusion groups, regardless of gender. More significant alterations of cranial base morphology were depicted in patients with Class II Division 2 malocclusions then in patients with Class II Division 1 malocclusion. The study�s results sustain the existence of some cranial base alterations in Class II malocclusions.

A study of the parameters that influence orthosurgical treatments

Introduction : In daily practice, the orthodontist may have some difficulties with their therapeutic decision to choose a treatment with or without orthognathic surgery, especially for borderline cases. The objective of this study is to determine the outcome of orthosurgical treatment.Patients and Methods : We undertook a retrospective analytical study of 175 randomly selected cases. The data for this study were obtained from lateral cephalograms radiographs, panoramic radiographs, both intraoral and extraoral photographs, and case sheet, and clinical examination.Results : According to the multivariate data analysis and the results of studied factors in determining the need for orthosurgical treatment were: the chin position, the FMA angle and the ratio of the lips based on this formula: 1.167 + 0.288 × the position of chin – 0254 × FMA angle −0.16 × the ratio of the lips. The critical score is equal to −5.92 in which case surgery is indicated.Conclusion : This study focused on a clinical and cephalometric approach in the decision related to orthosurgical treatment, so as to choose better treatment options and limit the damaged caused by a more complex and costly options.

Diagnose Anthropologique A Partir Des Caractéristiques Dento-Squelettiques Et D’épaisseurs Des Tissus Mous Du Profil Facial: Etude Comparative Entre Population Autochtone Et Diaspora Etrangère

Objective : The aim of this study was to search for the particularities in the dento-skeletal and soft tissue thickness of the facial cutaneous profile of Black Ivorians and White Lebanese. Material and methods: This cross-sectional and descriptive study, concerned with numerical radiographs extracted from medical files of 119 adolescent patients [62 Ivorians (34 females and 28 males) and 57 Lebanese (31 females and 26 males)], from 11 to 16 years old, with skeletal class I and normodivergent faces, in first orthodontic surgery. From a drawing on acetate paper (Kodatrace type) and the materialization of true vertical and true horizontal (TVL and THL), 30 landmarks (19 cephalometric and 11 facial cutaneous profile landmarks) allowed the construction of lines and plans as well as 17 dento-skeletal measurements (10 angular et 7 linear) and 12 soft tissue thickness measurements. The data reliability was verified by Dahlberg’s error method, while the t of student on independent series (signification threshold at 0,05) allowed to compare dento-skeletal characteristics and soft tissue thickness of the two groups. The Results : Compared to White Lebanese, Black Ivorians present a facial prognathism resulting in more pronounced protrusion of alveolar bases (SNA= 85,714°, SNB= 81,321°, A-NPerp= 5,768°) and vestibuloversion of central incisives (I/i= 111,679°, I/NA= 7,214mm, i/NB= 9,036mm, NA and NB (I/NA= 27,952° and i/NB= 36,266°) responsible of the obtuser facial convexity (NA-Pog= 169,338°). Indeed, this facial convexity reveals a very low prominence of the chin (Pog-NB= -0,565 mm). Also, the maxillomandibular discrepancy observed (FMA= 24,516°, greater), implies a more important facial growth kinetic in vertical direction with black Ivoirians. This is considerably reduced with females, with a less pronounced FMA angle compared to Lebanese females [FMA° (P=0,211 ns)]. The cutaneous effect of that dento-skeletal prognathism, is tangible through more protrusive lips – hence, thicker - lips (Id-Ls= 13,677 mm and id-Li= 15,919 mm). In this way, the observed substantial thickness is justified, of supporting peri-buccal soft tissue [lower lip’s base (B-Sm= 13,742 mm) and the most inferior part of the chin (Me-Me'= 7,984 mm)]. The two males groups present, however, a soft tissue thickness relatively similar on all the chin surface [Pog-Pog’ (P= 0,393 ns); Gn-Gn’ (P=0,251 ns); Me-Me’ (P=0,245 ns)]. The Black Ivorians’ nose, platyrrhines, low and diving, present a thicker back (Rhi-Rhi’= 3,741 mm) and thin supporting peripheral soft tissue thickness (ENA-Prn = 22,468 mm, Prn perp/Sn-N’=12,935 mm, A-Sn= 13,097 mm) in general. In addition to those specific characteristics of Black Ivorians, males have a thicker soft tissue on the root of the nose (N-N’= 6,769 mm). Among the two female groups, the characteristics of soft tissue thickness are much more contrasted. Thus, besides the traditional morphological features (nose more prominent - so, thicker - with Lebanese females, and thicker lips with Ivorian females), the forehead (G-G’= 6,441mm) and the chin (Pog-Pog’= 13,941mm, GnGn’= 10,471mm, Me-Me’= 8,618mm) of Ivorian females are thicker. Conclusion : The characteristics of dento-skeletal and soft tissue thickness of Black Ivorians and White Lebanese, reflect the anthropological diagnosis of their original ethnical groups. Facial prognathism and acuteness of facial convexity are observed, as well as greater soft tissue thickness of the inferior facial third (especially in females) traditionally particularizing the negroAfricans. However, a morphological proximity of the two ethnic groups is noticeable among males, concerning the soft tissue thickness of the chin, but also in females as for facial divergence. This study, because of what the results highlightened, has a forensic anthropology interest, and reveals the importance of radiological cephalometry.