Facial Height Ratio Research Articles

Soft Tissue Esthetic Changes Following a Modified Twin Block Appliance Therapy: A Prospective Study.

ABSTRACTAimAchieving a satisfactory facial esthetics is of utmost importance in the practice of orthodontics. Cl II div 1 patients often suffer from numerous adverse facial characteristics which may impair their social well-being. The objective of the current study was to evaluate the esthetic changes in such patients by using a modified twin block appliance.Materials and methodsSeventy adolescent patients with mandibular deficiency consecutively underwent treatment with a modified twin block appliance for a mean period of 13 months. Soft tissue analyzes of Burstone and Mcnamara were applied to evaluate the changes before and after the treatment. The esthetic changes before and after the therapy were compared using parametric paired t tests analysis. p values less than 0.05 were considered significant.ResultsFacial convexity, lip incompetence, upper lip protrusion, and columellar inclination significantly decreased (p < 0.05) while Merrifield's Z-angle nasolabial angle, lower lip length, and mentolabial angle significantly increased (p < 0.05). Vertical facial height ratio, lower lip protrusion, upper lip length as well as nasal projection and inclination, did not change significantly (p > 0.05)ConclusionOur findings indicated that a modified form of the twin block appliance can be substantially effective in the improvement of several aspects of patients’ facial balance with minimum untoward effects.Clinical significanceAdolescents suffering from mandibular deficiency can gain substantial facial balance with the twin block appliance. The whole face attractiveness, however, is another subject and should not be conflicted with the facial balance.How to cite this articleShahamfar M, Atashi MHA, Azima N. Soft Tissue Esthetic Changes Following a Modified Twin Block Appliance Therapy: A Prospective Study. Int J Clin Pediatr Dent 2020;13(3):255–260.

Assessment of Craniofacial Morphology in Mouth Breathing Children. A retrospective case-control study

The aim of this retrospective case-control study is to determine a possible correlation between breathing mode and craniofacial morphology. The study was carried out in the Department of Pedodontics,Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania. The sample comprised 80 patients, age between 6 and 13 years, which were divided in two groups based on respiratory pattern: control group composed of 38 nasal breathing children and case group composed of 42 oral breathing children. Three quantitative craniofacial parameters were measured from the frontal and lateral photos: facial index, lower facial height ratio and upper lip ratio. The statistical analysis showed a significant higher facial index (p=0.006*) and an increase lower facial height (p=0.033*) for the oral breathers group. No differences in facial morphology were found between genders and age groups, when comparing the data between the same type of respiratory pattern children. Spearman�s rho Correlation show a significant positive correlation (p=0.002*) between facial index and lower facial height and a significant negative correlation between facial index and upper lip (p=0,005*). Long faces children are more likely to develop oral breathing in certain conditions, which subsequently have a negative effect on increasing the lower facial height by altering the postural behavior of mandible and tongue.

Assessment of Craniofacial Morphology in Mouth Breathing Children. A retrospective case-control study

The aim of this retrospective case-control study is to determine a possible correlation between breathing mode and craniofacial morphology. The study was carried out in the Department of Pedodontics,Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania. The sample comprised 80 patients, age between 6 and 13 years, which were divided in two groups based on respiratory pattern: control group composed of 38 nasal breathing children and case group composed of 42 oral breathing children. Three quantitative craniofacial parameters were measured from the frontal and lateral photos: facial index, lower facial height ratio and upper lip ratio. The statistical analysis showed a significant higher facial index (p=0.006*) and an increase lower facial height (p=0.033*) for the oral breathers group. No differences in facial morphology were found between genders and age groups, when comparing the data between the same type of respiratory pattern children. Spearman’s rho Correlation show a significant positive correlation (p=0.002*) between facial index and lower facial height and a significant negative correlation between facial index and upper lip (p=0,005*). Long faces children are more likely to develop oral breathing in certain conditions, which subsequently have a negative effect on increasing the lower facial height by altering the postural behavior of mandible and tongue. Keywords: craniofacial morphology, facial growth, facial index, long face, oral breathing

Evaluation of condyle-fossa relationships in adolescents with various skeletal patterns using cone-beam computed tomography.

To evaluate the condyle-fossa relationship in adolescents with various skeletal patterns using cone-beam computed tomography (CBCT). CBCT images obtained in 120 adolescent patients were used for this study. The patients were divided into 3 groups according to 3 criteria: (1) age (early, middle, and late adolescence); (2) facial height ratio or Jarabak quotient (hyperdivergent, normodivergent, and hypodivergent); and (3) ANB classification (Class I, Class II, and Class III). Temporomandibular joint space (TMJS: AS, anterior space; SS, superior space; PS, posterior space; MS, medial space; LS, lateral space), width and depth of the condyle (MLT, mediolateral thickness; APT, anteroposterior thickness), articular slope (ArS) and vertical height of the fossa (VHF) were measured and compared using CBCT. Differences in condyle-fossa relationships were not significantly different between male and female adolescents, but were significantly different (P < .05) between left and right sides. The mean values showed no statistical differences according to age and skeletal pattern. Most measurements in the sagittal view showed that SS was the greatest, and the mean ratio of AS to SS to PS was 1.00 to 1.27 to 1.19, respectively. The mean values of coronal MS and LS were not significantly different. There were almost no statistical differences in the TMJS in adolescents across various factors except between left and right sides.

The study of facial morphology in patients with vertical growth pattern (hyperdivergent) lacking or showing temporomandibular disorders symptoms

AimAccording to the large number of studies, there seems to be a significant relation between hyperdivergence growth pattern and temporomandibular disorders. However, it is not clearly scrutinized which morphological factors can contribute to the development of temporomandibular disorders. The aim of this study was to investigate the relation between some skeletal and facial morphologic features of hyperdivergent facial growth pattern patients and temporomandibular disorders. Materials and MethodsThis case-control study was performed on a population of 50 patients including 25 patients with temporomandibular disorder and 25 non- temporomandibular disorder individuals aged between 15–30 years with hyperdivergent growth pattern (Frankfurt Mandibualr plane angle between 28 and 35 degree). Two groups of symptomatic and asymptomatic patients (case and control) were matched for age and gender. In order to evaluate the skeletal and dental variables, lateral cephalometries was taken and traced after obtaining written consent from the patients. The measured variables were A point to Nasion to B point, Frankfurt plane to Nasion to Pogonion, Nasion to A point to Pogonion, Sella to Gnathion to Frankfurt plan, Articular point to Gonion-Menton, Sella to Articular point to Gonion, Palatal plane to Mandibular plane, and Articular point to Gonion angles. The intervals of Basion to Nasion, Sella to Basion, Gonion to Menton, and amounts of Anterior facial height meas, Upper Anterior facial height ratio to Lower Anterior facial height, posterior facial height, overjet, and overbite Data were analyzed by Chi2 test, t-test, and multivariate test. ResultsAccording to the descriptive statistics, the age of the control and case groups averaged 21.12±1.99 and 21.63±1.58 years respectively. Among the people referred to the dental school, the frequency of males and females in the control and case groups were 6, 7 and 19, 18 respectively. The results of t-test and multivariate tests indicated significant differences between the two variables of overbite and mandibular length. ConclusionThe present study revealed increased overbite (dental feature) and mandibular length (skeletal feature) is more likely to be associated with a higher risk of temporomandibular disorders joint disease in patients with hyperdivergent facial growth pattern. Clinical significanceTreatment of the deep bite condition can be helpful in improving temporomandibular disorder.

3D Facial morphology in children affected by spinal muscular atrophy type 2 (SMAII).

The main objective of this study was to assess the three-dimensional facial characteristics of children affected by spinal muscular atrophy (SMA), a severe muscular disorder characterized by hypotonia, areflexia, weakness, and respiratory impairment. Stereophotogrammetric facial scans from 22 SMA type II patients aged 2-7 years were obtained. Data were analysed using both inter-landmark distances and principal component analysis and compared with data collected from matched control subjects. Patients had wider transverse facial diameters, but smaller biocular width. Middle and lower anterior face heights were increased, whereas the mandibular ramus was shorter, with a reduced posterior-to-anterior face height ratio. Facial width-to-length ratio was reduced. In the sagittal plane, mandibular body length, and facial divergence were increased, whereas the gonial angles were decreased. In the horizontal plane, lower facial convexity was greater in patients, whereas mandibular convexity was smaller. Patients had smaller and down-slanted eye fissures, with a larger and more vertically developed nose. This study assessed a relatively small number of patients, due to the rare frequency of SMA type II. SMA type II children possess peculiar facial alterations that may be due to the altered muscular activity. As feeding problems may derive also by malocclusion and masticatory muscular alterations, a detailed assessment of the craniofacial individual alterations should be considered in the standards of care of these patients.

Craniofacial photography and association with sleep-disordered breathing severity in children.

Sleep-disordered breathing (SDB) in children has been associated with craniofacial characteristics. Facial photography provides a radiation-free means of estimating facial morphology through facial landmark analysis. Our objective was to determine whether facial analysis provides information about SDB severity. Specifically, we aimed to determine whether facial photographic measurements differ with SDB status, or were associated with SDB severity. Single-center cohort of children undergoing overnight polysomnography for assessment of SDB; non-snoring controls were recruited from the community to undergo polysomnography. Standardized front and lateral facial photographs were analyzed according to previously published protocols. Multivariate analysis of variance was used to determine if facial measurements differed between SDB groups and controls. Linear regression was performed to determine if facial measurements were associated with SDB severity. Seventy-eight children (9 controls, 17 primary snoring, 23 mild SDB, 27 moderate-severe SDB) were included. Facial angles and upper-to-lower face height ratio showed variation between SDB groups (p = 0.038). Facial measurements related to SDB severity, specifically an increased cervicomental angle (p = 0.001), and increased lower-to-upper face height (p = 0.006). Evaluation of craniofacial features using clinical photography is feasible. Preliminary investigation shows some relationship with SBD severity. Further work is needed to determine if craniofacial photography is useful for stratifying SDB risk in children.

Indian Board of Orthodontics Case Report: Management of a Skeletal Cl II Malocclusion Using Two-phase Treatment with a Standard Twin Block Appliance

NK, a 12-year-old male patient, presented with a Class II division 1 incisor relation on a Class II skeletal base with a decreased maxillomandibular plane angle and decreased face-height ratio. He had a convex profile, incompetent lips, lip trap, deep mentolabial sulcus, everted lower lip and a positive VTO (Visual Treatment Objective). Intraorally, he presented with bilaterally Angle’s Class II molar relation and canine relation, scissor bite in the region of first premolars bilaterally, a closed bite and a 13 mm overjet. He presented with mild spacing in the upper arch and mild crowding in the lower arch with a pronounced curve of Spee. This was further complicated as the LR6 was endodontically treated and temporarily restored; also, enamel hypoplasia was seen in all permanent first molar region. The treatment was carried out in two phases, Phase I involved growth modulation done with a twin block appliance, and Phase II was the postfunctional orthodontic phase for dental corrections and finishing and detailing of occlusion, which was done with a preadjusted edgewise appliance (0.022 × 0.028˝ slot) with MBT (McLaughlin, Bennett, Trevisi) prescription. The posttreatment results were highly satisfactory, showing improvement in facial esthetics and occlusal traits as well as good long-term stability as was evident in the 3-year retention records.

Moebius syndrome: The challenge of dental management.

Moebius syndrome (MBS) is a rare disorder which involves unilateral or bilateral paralysis or lack of the VI and VII cranial nerves. This is accompanied by abnormalities affecting the head, mouth, upper and lower limbs, and chest. A distinguishing feature of this syndrome is the so-called mask-like face. A small number of publications relating to occlusal and dental bnormalities and documenting the progress of orthodontic treatment has led the authors to present the case of a patient with Moebius syndrome. A patient with Moebius syndrome was initially treated by means of removable appliances and later by means of a fixed appliance after permanent tooth extractions. As a result of the treatment, there was an improvement in the ratio of the posterior facial height to the anterior facial height: Sgo/NGn increased from 55.8% to 59.1%, which is closer to the Caucasian population norm. The aesthetic result was satisfactory both for the patient and for her parents.

Three-dimensional cephalometry for orthognathic planning: Normative data and analyses

The objective of this study was to create a normative database of 3D cephalometric measurements for adult Chinese in Taiwan to understand the specific features, as well as to provide information for 3-dimensional (3D) orthognathic surgery planning for patients with maxillofacial deformity. A cross-sectional study was conducted on 30 male and 30 female adults with normal and balanced facial appearance, skeletal Class I pattern, and proper interincisal relationship with normal occlusion. Cone-beam computed tomography was performed. After standard orientation of the 3D image models, 51 landmarks were digitized and 3D cephalometric measurements of overall facial features, midface, maxilla, mandible, dentoalveolus, and soft tissue were performed and analyzed. Reliability and reproducibility of the 3D measurement were achieved. The data showed significant differences between males and females in facial height ratio, midface prominence, midface and maxilla width, mandible width and length for the skeleton, lower incisal inclination and interincisal angle for the dentoalveolus, and lip height, facial height and chin throat angle for the soft tissue. These dataset presented specific facial characteristics of the Chinese face as compared with other populations. The normative data helps to serve as a guide for maxillofacial treatment for globally ethnic Chinese, particularly useful for orthodontic treatment, 3D planning of orthognathic surgery and outcome assessment. Gender and ethnic differences need to be taken into consideration.

Determining condylar bone density in adolescents: An inconclusive cone-beam computed tomographic study

In an article in the September issue of the journal, Kim et al attempted to determine the condylar bone density in different age groups and various skeletal patterns. (Kim KJ, Park JH, Bay RC, Lee MY, Chang NY, Chae JM. Mandibular condyle bone density in adolescents with varying skeletal patterns evaluated using cone-beam computed tomography: A potential predictive tool. Am J Orthod Dentofacial Orthop 2018;154:382-9). We appreciate the efforts of the authors and thought it was a great attempt to explore some unknown findings about condylar bone density, but certain points need to be addressed. As mentioned in the text, “The bone density of the mandibular condyle is affected by the functional pressure generated by the occlusion and the mandibular movements that are, in turn, influenced by the properties of the masticatory muscles and age.” Also, “Skeletal pattern is thought to be closely related to occlusal force.” Thus, the authors mentioned that age, sex, and occlusion type (Class I, II, III) affects the condylar bone density. But they do not mention confounding factors, which could alter the results of the study. For example, they did not mention the number of hyperdivergent, hypodivergent, or normovergent cases when the subjects were divided into Classes I, II, and III; the number of cases of hypodivergent subjects in Classes I and II might vary. Facial height ratio (which might be the actual factor responsible for variation of condylar bone density) acts as a confounding factor and can give us biased results. Also, the numbers of boys and girls in the Class I, II, and III groups were not the same, so sex as a confounding factor affects the result. Similarly, when the authors divided the subjects into hypodivergent, normovergent, and hyperdivergent groups, the number of Class I, II, and III cases and the sex of the subjects can act as confounding factors.1Jain S. Debbarma S. Jain D. Bias in dental research/dentistry.Ann Int Med Dent Res. 2016; 2: 2395-2814Google Scholar Nor did the authors mention the different adolescent age groups in the hyperdivergent and Class II groups versus other groups. It is quite possible that the results, which showed higher condylar bone density in Class II and hyperdivergent groups, might be due to a greater number of late adolescent subjects in these groups. Another important point to be noted in the study is that the standard deviation is more than the difference between bone density in different groups.2Jain S. Sharma N. Jain D. Basic fundamentals of designing a quality research.J Adv Med Dent Sci Res. 2015; 3: 88-95Google Scholar The authors did not mention the 95% CIs. P value and CIs are common statistical measures that provide complementary information about probability and conclusions regarding the clinical significance of the study.3Gupta A. Interpreting research findings with confidence interval.J Orthod. 2015; 1: 8Google Scholar Therefore, if we calculate the CIs, the values of the bone density would overlap within different groups and make the results less clinically significant. The value of difference in bone density of the different groups are very close to each other. For example, as mentioned in Table IV, total bone density difference in Class 1 and Class II is just 13 HU; when the samples are improperly distributed in terms of sex or age, that raises questions about clinical significance. Similarly, in Table III, normovergent and hyperdivergent groups have a difference of 21 HU in total bone density. The authors described the results to be statistically significant, but clinical significance of the results is doubtful. Thus, the results can not be held as conclusive as stated in the conclusion of the article. These might be factors causing different bone densities, but again, the results can not be held as conclusive. Mandibular condyle bone density in adolescents with varying skeletal patterns evaluated using cone-beam computed tomography: A potential predictive toolAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 154Issue 3PreviewThe aim of this study was to evaluate the bone density of mandibular condyles in adolescents with varying skeletal patterns using cone-beam computed tomography. The null hypothesis was that there is no difference in the bone density of mandibular condyles in adolescents across various facial height ratios, ANB angle classifications, sexes, and age categories. Full-Text PDF Authors' responseAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 155Issue 3PreviewThank you very much for your interest in our article. We truly appreciate your insightful questions and valuable suggestions. We agree that all of the factors listed can influence condylar bone density, and that they may interact with one another in doing so. Optimally, a full factorial analysis would be conducted on these data. Unfortunately, this type of analysis requires a very large data set. When we attempted to combine predictors, the matrices contained a number of very small groups, and even some empty cells. Full-Text PDF

Growth patterns and overbite depth indicators of long and short faces in Korean adolescents: Revisited through mixed-effects analysis.

The purpose was to evaluate skeletal factors related to the growth of subjects with skeletal open and deep bites based on lateral cephalographs from 9years of pure longitudinal data using mixed effect analysis. Fifty-one children with extreme lower anterior facial height to total anterior facial height (LAFH/TAFH) ratio values at the age of 14 were assigned to either skeletal open bite or skeletal deep bite groups from a total of 223 subjects. The palatal plane angle (PPA), mandibular plane angle (MPA), gonial angle (GA), palatomandibular plane angle (PMA), upper gonial angle (UGA), lower gonial angle (LGA), occlusal plane angle (OPA) and overbite depth indicator (ODI) were measured and analysed. Mixed-effects regression model analysis was used for the interpretation of data with random effects. Morphological differences were evident from the beginning and became more pronounced with age in MPA, GA, PMA, ODI and LGA. The initial values of all variables were statistically significant. Annual increases with age were statistically significant in GA, OPA, ODI and UGA. The morphological differences in the annual increases in MPA, GA, PMA and UGA were also statistically significant. Morphologically different growth patterns were mainly contributed by lower anterior facial height dimensions. The extent of individual variations mandates judicious decision-making in clinical situations.

Relationships between craniofacial morphology and masticatory muscle activity during isometric contraction at different interocclusal distances

Objective: The aim was to investigate relationships amongst interocclusal distances, masticatory muscle electromyographic (EMG) activity during isometric contraction of masticatory muscles, and craniofacial morphology.Design: Twenty-eight women and 12 men (25.3 ± 3.8 years old) participated. After measuring maximal voluntary occlusal bite force (MVOBF) between the right-first premolars, the participants were asked to bite at submaximal levels of 0 (= holding the bite force transducer), 15, 22.5, and 30% MVOBF with the use of visual feedback. The thickness of a bite force transducer was set at 10, 12, 13, 14, 16, 17, 18, 19, 20, 22, and 24 mm (= interocclusal distance: IOD). Nine soft tissue craniofacial factors were assessed through digital photograph: face height, middle face height, lower face height, face width, inter-pupil distance and mandibular plane angle, lower face height / face height ratio, inter-pupil distance / facial width ratio and face width / face height ratio.Results: In the masseter muscle, EMG activity decreased with increased IODs. The participants with higher mandibular plane angle had more negative slope coefficients of IOD-EMG graphs at 0% MVOBF especially in male temporalis and female masseter and temporalis muscles, suggesting that a greater mandibular plane angle is associated with lower EMG activity at longer IOD.Conclusions: Overall the findings support the notion that craniofacial morphology is associated with differences in neuromuscular activity of the masticatory muscles, and suggest that the neuromuscular effects of oral appliances may be dependent on patients’ craniofacial morphology and the thickness of the device. (247/250 words)

Mandibular condyle bone density in adolescents with varying skeletal patterns evaluated using cone-beam computed tomography: A potential predictive tool.

The aim of this study was to evaluate the bone density of mandibular condyles in adolescents with varying skeletal patterns using cone-beam computed tomography. The null hypothesis was that there is no difference in the bone density of mandibular condyles in adolescents across various facial height ratios, ANB angle classifications, sexes, and age categories. We divided 120 adolescentpatients, 56 boys and 64 girls, into 3 groups according to 3 criteria: (1) age (early, 10 to<14years; middle, 14 to<17years; late, 17 to<20years); (2) facial height ratio or Jarabak quotient (hyperdivergent: facial height ratio,<62%; normovergent: facial height ratio, 62% to≤65%; and hypodivergent: facial height ratio,>65%); and (3) ANB angle classification (Class I, 1° to≤4°; Class II, (>4°); and Class III,<1°). The total, cortical, and cancellous bone densities were measured and compared on the axial slice with the largest mediolateral diameter of the mandibular condyle using C-mode cone-beam computed tomography. Cortical bone density increased as age increased and showed statistically significant differences between the early and middle (P=0.041) and the early and late adolescent groups (P=0.031). Condylar bone density increased as facial height ratio decreased, and cancellous bone density showed statistically significant differences between the hyperdivergent and hypodivergent groups (P=0.038). The cortical, cancellous, and total bone densities increased as ANB angle increased and showed statistically significant differences between the Class II and Class III groups (P=0.022, P=0.006, and P=0.003, respectively). The null hypothesis was rejected. Condylar bone density increased as facial height ratio decreased and ANB angle increased. These findings may be useful in predicting the vertical and horizontal skeletal growth patterns of growing adolescents.

Evaluation of skeletal variations and establishment of Cephalometric Norms in Saudi Sub Population using Bjork Jarabak's analysis.

Objective:To evaluate the skeletal variations amongst individuals and to compare the measurements with the standardized linear and angular values of Bjork Jarabak’s analysis.Methods:This study was conducted at POS Department, King Khalid University on 100 adult Saudi patients recruited through convenience sampling. It was conducted between April to September 2017, had inclusion criteria of patients between the age group 17 to 22 years showing normal occlusion. After history and examinations, lateral cephalographs were taken, scanned and traced using Dolphin Imaging Software and Cephalometric points were recognized. Linear and angular dimensions were calculated according to Bjork-Jarabak’s method.Results:Analysis and assessment of Saudi male and female values revealed considerable variation in the anterior and posterior cranial base lengths (p<0.05), anterior and posterior face height, ramus height, and mandibular length. Male measurements in contrast to Jarabak’s values showed noteworthy variances in articular angle, anterior and posterior cranial base, ramus height, length of mandible, anterior face height and Jarabak’s ratio. Female dimensions in relation to Jarabak’s norms showed considerable variances in articular angle, anterior cranial base, posterior facial height with less significant values in Saudi females while compared with Jarabak’s norms apart from mandibular body length which is more in Saudi females.Conclusion:Skeletal variations amongst Saudi males and females were significant and comparison with standardized linear and angular values of Bjork Jarabak’s analysis was also significant.

Effects of strong bite force on the facial vertical dimension of pembarong performers

Background: A pembarong performer is a reog dancer who bites on a piece of wood inserted into his/her mouth in order to support a 60 kg Barongan or Dadak Merak mask. The teeth supporting this large and heavy mask are directly affected, as the strong bite force exerted during a dance could affect their vertical and sagital facial dimensions. Purpose: This study aimed to examine the influence of the bite force of pembarong performers due to their vertical and sagital facial dimensions. Methods: The study reported here involved fifteen pembarong performers and thirteen individuals with normal occlusion (with specific criteria). The bite force of these subjects was measured with a dental prescale sensor during its centric occlusion. A cephalometric variation measurement was subsequently performed on all subjects with its effects on their vertical and sagital facial dimensions being measured. Results: The bite force value of the pembarong performers was 394.3816 ± 7.68787 Newtons, while the normal occlusion was 371.7784 ± 4.77791 Newtons. There was no correlation between the bite force and the facial sagital dimension of these subjects. However, a significant correlation did exist between bite force and lower facial height/total facial height (LFH/TFH) ratio (p = 0.013). Conversely, no significant correlation between bite force and posterior facial height/total facial height (PFH/TFH) ratio (p = 0.785) was detected. There was an inverse correlation between bite force and LFH/TFH ratio (r = -.464). Conclusion: Bite force is directly related to the decrease in LFH/TFH ratio. Occlusal pressure exerted by the posterior teeth on the alveolar bone may increase bone density at the endosteal surface of cortical bone.

Longitudinal cephalometric growth of untreated subjects with Class II Division 2 malocclusion

Our objective was to evaluate the craniofacial growth of subjects with untreated Class II Division 2 malocclusion. A mixed longitudinal sample of 39 white Class II Division 2 subjects was analyzed at 5 time points: T1 (6 or 7years), T2 (9 or 10years), T3 (12 or 13years), T4 (15 or 16years), and T5 (18 or 19years). They were compared with an age- and sex- matched sample of Class I controls. Seventeen measurements (12 angular, 5 proportional) were computed. Multilevel modeling procedures were used to statistically describe the growth changes and to evaluate group differences. There were no group differences in the relative sizes and anteroposterior positions of the jaws during childhood, adolescence, or early adulthood. Subjects with Class II Division 2 malocclusion demonstrated significantly (P<0.05) smaller mandibular plane angles, smaller palatal-to-mandibular plane angles, larger posterior-to-anterior facial height ratios, smaller gonial angles, smaller cranial base angles, larger interincisal angles, and more retroclined maxillary incisors than did the Class I subjects. The hypodivergent patterns were established early and became more pronounced over time. Group differences in the mandibular plane angle, palatal-to-mandibular plane angle, gonial angle, interincisal angle, and maxillary incisor-to-cranial base angle, as well as the posterior-to-anterior facial height ratio all increased over time; the difference in the cranial base angle remained unchanged over time. Retroclination of the maxillary incisors occurred primarily during the early mixed dentition. Subjects with Class II Division 2 malocclusion are more hypodivergent and have more upright maxillary incisors than do subjects with Class I occlusion. Hypodivergence establishes itself early and increases progressively through early adulthood; maxillary incisor retroclination occurs early.

Evaluation of Mandibular Condylar Changes in Patients Following Orthognathic Surgery: A Retrospective Study.

Background:Condylar resorption as a cause of relapse after orthognathic surgery is well known. Several authors have presented evidence of the relation between orthognathic surgery and condylar remodeling and resorption. This study was done to appraise the condylar changes along with the form and function following orthognathic surgery, as well as to assess what factors may have contributed to the problems.Methodology:A diagnosis of progressive condylar resorption (PCR) was made by comparison of preoperative and postoperative radiographs (cephalometric radiograms), as well as clinical evaluations. The radiographs were taken for each patient preoperatively and postoperatively, which include immediately after osteotomy, at 6 months and 24 months. Additional radiographs were taken when required. Then, preoperative and postoperative tracings were compared at 24 months postoperatively.Results and Conclusion:It can be concluded from this study that females of relative low age (<18 years) appeared to be a high-risk factor for the occurrence of condylar alteration including PCR. A steep mandibular plane angle, the low facial height ratio (post/ant), and magnitude of surgery were also significantly related to the occurrence of condylar alteration, but the multivariance regression showed that these parameters had only limited value.

Differences in bite force between dolichofacial and brachyfacial individuals: Side of mastication, gender, weight and height

PurposeDue to the bite force importance in functionality of the masticatory system, this study aimed to characterize it in dolichofacial and brachyfacial individuals. MethodsA sample comprised by 190 patients was divided into two groups: 90 severe dolichofacial, and 100 severe brachyfacial individuals classified according to the VERT index and the face height ratio (Jarabak quotient). Bite force was measured by using an adjusted digital dynamometer and proper methodology. ResultsThe sample met the parametric assumptions and presented statistical significance when right and left sides of dolichofacial and brachyfacial individuals were compared. However, within the same group, no differences between the left and right sides were found. Generally, bite force was higher for male, left masticator, age between 41–50 years, weighing over 100kg and between 1.81 and 1.90m tall. ConclusionsBased on the results of this cross-sectional study, it was possible to conclude that the bite force in severe brachyfacial individuals was significantly higher than in severe dolichofacial individuals, being influenced by gender, weight and height.

Occlusal and cephalometric characteristics of anterior open bite in 5-10 year-old Colombian school children

Objetive. The aim of this study was to determine oclussal and skeletal characteristics of anterior open bite (AOB) according to sex and socioeconomic status (SES) in school children in the municipality of Pasto, Colombia. Methodology. A cross-sectional study was carried out involving 384 children between 5 and 10 years of age. A clinical assessment was performed to evaluate AOB, and information regarding socio-demographic variables, such as sex and SES according to Colombian standards, was obtained. Standardized lateral cephalograms and cast models were taken from participating subjects. A statistical analysis was performed using frequencies, percentages, t-student, ANOVA, Mann-Whitney and Kruskal-Wallis tests. Results. Prevalence of AOB was 8.1%, showing a significant difference according to SES. The most common Angle’s classification was Class II with 70.6% in the right molars, and 58.8% in the left molars, according to occlusal characteristics. Statistically significant differences were observed in the ratio of posterior and anterior facial height (PFH:AFH) (p=0.050) according to sex. The distance between the upper first molar and palatal plane (U6-PP) (p=0.028), the Overbite (p=0.032) and Gonial° (p=0.033) values showed statistically significant differences according to SES in vertical skeletal measures. The 64.7% of AOB were of dental origin. Conclusion. Results suggest variations in some vertical skeletal measures according to sex and SES in children with AOB. Since a high percentage of AOB is caused by dental factors, preventive programs are required to control this condition.