Cephalometric norms of Nigerian children.

INTRODUCTION: The purpose of this study was to develop cephalometric standards for Nigerian children. METHODS: The average values of 7 dentoskeletal angles were determined from standardized lateral head radiographs of 100 schoolchildren (aged 11 to 13 years; mean, 12.6 years) in Enugu, a city in southeastern Nigeria. The children, born to Nigerian parents of Igbo ancestry (Igbo is 1 of the 3 major ethnic groups in Nigeria), were selected on the basis of a well-balanced face and acceptable profile, Class I occlusion with normal overjet and overbite, minor or no crowding or spacing, and no history of orthodontic treatment. RESULTS: There were no statistically significant differences in cephalometric measurements between boys and girls; thus, the data were combined for analysis. The mean values and standard deviations obtained for the measured variables were: SNA, 85.5 degrees (+/- 4.3 degrees); SNB, 81.2 degrees (+/- 4.0 degrees); ANB, 4.3 degrees (+/- 2.5 degrees); UI-FP, 122.8 degrees (+/- 7.5 degrees); Ll-MP, 98.8 degrees (+/- 5.8 degrees); Ul-LI, 109.1 degrees (+/- 8.0 degrees); and FMA, 26.1 degrees (+/- 5.0 degrees). CONCLUSIONS: Compared with the norms for other ethnic groups, Igbo children have a prognathic relationship of the maxilla and the mandible to the anterior cranial base with a tendency toward a protrusive skeletal pattern. The children also exhibited prominent bimaxillary proclination with procumbent and protrusive maxillary and mandibular incisors and a steep Frankfort-mandibular plane angle. The findings emphasize the need for group-specific norms for orthodontic diagnosis and treatment planning, and provide cephalometric standards for Igbo children.     

Craniofacial growth in untreated skeletal Class I subjects with low, average, and high MP-SN angles: A longitudinal study

Sixty-eight (36 male and 32 female) untreated skeletal Class I subjects with low (< or = 27 degrees ), average (>27 degrees - <37 degrees ), and high (> or = 37 degrees ) mandibular plane (MP-SN) angles were selected from the Bolton-Brush and Burlington Growth Studies. Cephalograms of each subject at ages 9 and 18 were traced, and 28 parameters were measured. The difference in each parameter from ages 9 to 18 was calculated, and comparisons were made between the groups with low, average, and high angles. Results showed that, for boys and girls at age 9, the low-angle groups exhibited significantly larger SNA angle, SNB angle, facial taper, PFH, PFH:AFH, and ramus height, and the high-angle groups showed significantly larger ANS-Me and gonial angle. From ages 9 to 18, all the male and female low-, average-, and high-angle groups showed an increase in SNA and SNB angles, and PFH:AFH, and a decrease in ANB angle, convexity (more flattened face), MP-SN angle, and gonial angle (mandibular forward rotation). The dental measurements showed few changes with growth in all groups. In terms of skeletal measurements from ages 9 to 18, similar growth changes were found between the sexes in most angular measurements, but males had larger values in linear measurements than females.     

Cervical Headgear Treatment and Growth Patterns: Analysis by Lateral Cephalometry

OBJECTIVE: Retrospective cephalometric study of changes in vertical and sagittal relations after headgear treatment depending on preexisting growth patterns. MATERIALS AND METHODS: Lateral cephalograms obtained from 119 patients before and after headgear treatment were analyzed. All patients were treated with headgears exclusively. Only cases were included that showed bilateral improvement of least 4 mm in Class II occlusion after headgear treatment lasting at least 6 months. Patients were assigned to six groups based on y-axis values obtained at baseline. RESULTS: Almost all groups revealed substantial improvements in skeletal Class II relations, including 1.38 degrees-1.72 degrees reductions in ANB angles and 0.62-0.81 mm reductions in Wits values. SNA values fell by 0.51-1.25 degrees. SNB angle values increased by 0.21 degrees-0.95 degrees. SN-MeGo angles and mandibular angles were reduced, while y-axis values remained essentially unchanged during headgear treatment. Different results were only obtained in the group with the most pronounced horizontal growth pattern. Those patients revealed lower SNB angle values (-0.93 degrees ) and increased vertical relations (y-axis: +1.39 degrees ; SN-MeGo angle: +1.22 degrees; mandibular angle: +0.01 degrees) after headgear treatment. All groups showed a reduction in basal plane angles and maxillary retroinclination after treatment. CONCLUSION: Our results do not support the conventional recommendation that cervical headgears should not be used in the presence of vertical growth patterns.     

Craniofacial growth in untreated skeletal Class II subjects: A longitudinal study

Eighty-five (45 male and 40 female) skeletal Class II untreated subjects with low (< 27 degrees ), average (27 degrees - 36 degrees ), and high (> 36 degrees ) mandibular plane angles (MP-SN) were selected from the Bolton-Brush and the Burlington Growth Studies. Cephalograms of each subject at ages 9 and 18 were traced, and 28 parameters were measured. The difference in each parameter from ages 9 to 18 was calculated, and comparisons were made between the groups with low, average, and high angles. Results showed that for children at age 9, the high-angle group showed greater convexity, larger Y-axis and gonial angles, and greater anterior facial height, and the low-angle group had larger SNA and SNB angles, and greater posterior cranial base, mandibular body, ramus height, and posterior facial height. From ages 9 to 18, all the low-, average-, and high-angle groups showed a decrease of convexity (more flattened face) and a mandibular forward rotation (decreased MP-SN). The low-angle group displayed significantly more facial flattening and more mandibular forward rotation than did the high-angle group. Moreover, the mandibular incisors became more retroclined in the low-angle group and more proclined in the high-angle group with age. Comparisons between males and females showed similar skeletal growth patterns in angular measurements. However, a significant sex difference was noted in some linear measurements.     

Segment stability in bimaxillary orthognathic surgery after resorbable Poly(L-lactide-co-glycolide) versus titanium osteosyntheses

This study compared segment stability after bimaxillary orthognathic surgery, comparing poly(L-lactide-co-glycolide) with titanium osteofixation at 12 months follow up. Fifteen patients were osteofixated with poly(L-lactide-co-glycolide) copolymer, 30 with 2.0-mm titanium miniplates. Preoperative, postoperative, and 1-year follow-up lateral cephalograms were analyzed. Maxillary average advancement in resorbable plate osteosyntheses (+/- standard deviation) was (case numbers/titanium controls) 2.5 (+/- 1.0) mm; n = 7/5.4 (+/- 3.5)mm; n = 21, setback 2.2 (+/- 2.4) mm; n = 7/1.9 (+/- 1.8) mm; n = 8, elongation 6.5 (+/- 3.4) mm; n = 9/3.7 (+/- 5.2) mm; n = 14, intrusion 1.0 (+/- 0.7) mm; n = 5/3.3 (+/- 2.7)mm; n = 13, mandibular average advancement was 5.5 (+/- 3.7) mm; n = 4/6.3 (+/- 8.8) mm; n = 18, setback 11.2 (+/- 7.7) mm; n = 7/7.2 (+/- 3.2) mm; n = 12, mandibular angle enlargement 7.9 (+/- 2.4) degrees ; n = 9/7.9 (+/- 6.6) degrees ; n = 21, reduction 6.9 (+/- 2.6) degrees ; n = 4/6.3 (+/- 6.6) degrees ; n = 9. Changes in landmark position within the study and control groups differed significantly in paired t testing (P =.01); operative movements were comparable in between study and control groups (P = 0.5, two-sided t test), only maxillary advancement was significantly smaller (P = 0.04) within study cases. Absolute instability at advanced A-point was (study group/controls) 1.2 (+/- 0.8)/2.4 (+/- 2) mm; setback 1.8 (+/- 1.9) mm/2.5 (+/- 1.7) mm; elongation at anterior nasal spine (ANS) 2.0 (+/- 1.4) mm/3.1 (+/- 3.6) mm, intrusion 1.1 (+/- 1.1) mm/2.2 (+/- 1.5) mm; advancement instability at B-point was 2.6 (+/- 2.7) mm/5.1 (+/- 8.2) mm, setback 2.7 (+/- 2.6) mm/1.7 (+/- 2) mm; mandibular angle enlargement instability 2.4 (+/- 2.7) degrees /8.2 (+/- 9.6) degrees , angle narrowing 7.0 (+/- 5.4) degrees /4.2 (+/- 5.9) degrees . Absolute postoperative instability was not significantly different in between study and control groups (P = 0.3). Tested resorbable poly(L-lactide-co-glycolide) osteofixation proved to be as reliable in segment fixation as titanium; however, study and control groups were not matched; the study group was small and therefore the results (especially advancement) have to be interpreted as preliminary until larger prospective cohorts become evaluated.     

Effects of a magnetic appliance in functional Class III patients

The aim of this study was to determine the effects of a magnetic appliance in functional Class III patients. Standardized lateral head cephalograms and hand-wrist films of 10 subjects (mean age nine years seven months) were taken. These records were repeated after a period of one year, and the serial films were compared to determine the direction of facial growth as the control group. After this observation period, the magnetic appliance was placed in the 10 patients for approximately 9.4 months. The significant findings showed a posterior rotation of the mandible (x = 2.1 +/- 0.7 degrees), increased overjet (x = 4.8 +/- 0.3 mm), decreased overbite (x = -3.7 +/- 0.7 mm), protrusion of the upper incisors (x = 6.2 +/- 1.2 degrees), retrusion in the lower incisors (x = -0.6 +/- 0.3 degrees), reduced SNB angle (x = -1.8 +/- 0.8 degrees), increased ANB angle (x = 1.9 +/- 0.3 degrees), and an increased mandibular plane angle (x = 2.1 +/- 0.7 degrees). The results of this study indicate that the primary effect of magnetic appliance was the increase in the posterior rotation of the mandible.     

Prediction of mandibular growth in Japanese children age 4 to 9 years

PURPOSE: The purpose of this study was to propose mathematical models for predicting mandibular growth direction and amount in children with normal skeletal relationship from 4 to 9 years of age using the craniofacial characteristics found on the head films. METHODS: Lateral cephalograms of 27 Japanese children with normal occlusion at 4 (T1) and 9 (T2) years of age were traced and measured. Fifteen linear and angular measurements were performed. The angle NSGn and the distance S-Gn were used to represent the growth direction of the mandible and its growth amount, respectively. The data were analyzed by multiple linear regression analysis. RESULTS: The multiple regression analysis revealed 2 models for the mandibular growth prediction. The equation (model) for the mandibular growth direction is YD=-39.844+1.206 X1 +0.333 X2, where YD is the predicted value of the angle NSGn at T2. X1 is the value of the angle NSGn at T1 and X2 is the value of the angle SNB at T1 (R2=0.719, P<0.05). The equation for the mandibular growth amount is YA=99.052+0.782 X3-0.517 X4, where YA is the predicted value of the distance S-Gn at T2. X3 is the distance S-Gn at T1 andX4is the angle NSAr at T1 (R2=0.610, P< 0.05). CONCLUSIONS: The direction of the mandibular growth at 9 years of age can be predicted by 72% with the regression equation using the angles NSGn and SNB at 4 years of age. The amount of growth of the mandible can be predicted by 62% by using the distance S-Gn and the angle NSAr at 4 years old. The model for the growth amount provides a relatively lower predictive value than that of the growth direction.     

快速生长期骨性安氏Ⅱ类下颌后缩患者使用无托槽隐形矫治器前导下颌的临床效果分析

目的 评价无托槽隐形矫治技术MA(mandibular advance)矫治安氏Ⅱ类骨性下颌后缩畸形的临床效果。方法 收集符合条件的2018年1月至2021年5月至常熟市中医院口腔科就诊的处于生长发育高峰期的安氏Ⅱ类骨性下颌后缩19例患者资料，平均年龄(12.32±1.51)岁。10例患者经MA导下颌向前治疗。9例未治疗患者作为对照组。矫治前后或观察前后拍摄头颅定位侧位片。对X片测量并进行统计学分析。结果 与对照组相比，治疗组SNB、L1-NB、L1-NB距、L6-MP距、Z角治疗后明显增加(P<0.05);Co-Go、Co-Gn、SL增加量明显大于对照组(P<0.05);ANB、U1-SN、U1-NA、U1-NA距、L1-MP、FCA治疗后明显减小(P<0.05);治疗组SE无明显变化，而对照组明显增加(P<0.05)。结论 MA可以促进下颌发育，矫治下颌后缩畸形，改善骨性畸形和侧貌；且可以维持下前牙唇倾度及下颌平面角。     

Analysis of dental casts of 6-8- and 12-year-old Kenyan children

Dental plaster casts of 97 6-8-year-old and 173 12-year-old Maasai, Kikuyu, and Kalenjin children were studied. The Kikuyu are Bantu, while Maasai and Kalenjin are Nilo-Hamitic subjects. The variables measured were palatal depth (PD) and length (PL); maxillary and mandibular anterior arc circumferences (AC1) and (AC2), respectively; posterior arc circumferences (PC1) and (PC2), inter-canine (CC1), and (CC2); inter-molar (MM1) and (MM2) distances, and mandibular length (ML). The data were analysed using SPSS package. The mean values of all the variables were generally higher in the males compared with the females and significant sex differences in the means (P < 0.01) were found in AC1, PC1, PC2, CC1, CC2, MM1, and MM2 in the 12-year-old subjects. The means of all variables, except PL, ML, PC2, and CC2, increased from 6 to 12 years of age and significant differences in the means for age were found in ML, AC1, PC2, PD, MM1, MM2, and CC1. Mean maxillary inter-molar distance increased with age by 0.17-0.34 mm in the three groups. Mean values of mandibular variables were highest in the Kikuyu, while maxillary variables were highest in the Maasai. The Maasai casts showed a marked decrease in CC2, PC2, AC2, and ML compared with the Kikuyu and Kalenjin. Ethnic and sex differences in the dental arches may be masked by anterior tooth positions that are influenced by the dento-alveolar complex and soft tissues. Corresponding mandibular and maxillary variables were strongly correlated and anterior and posterior arc circumferences were correlated with inter-canine and intermolar distances. Details of the norms for dental arch dimensions and changes with age may allow for appropriate assessment of dental occlusion and treatment planning for Kenyan children.     

The effects of perennial allergic rhinitis on dental and skeletal development: a comparison of sibling pairs

This study analyzed the effect of perennial allergic rhinitis on dental and facial skeletal characteristics. Twenty-five allergic children who were apparent mouth breathers, their 25 siblings who did not have the disease and were apparent nose breathers, and 14 nasal breathing control subjects were examined medically, dentally, and cephalometrically. Compared with their siblings, the allergic subjects had more nasal mucosal edema, a higher proportion of eosinophils in their nasal secretions, and greater nasal power. The allergic subjects were characterized by deeper palatal height, retroclined mandibular incisors, increased total anterior facial height and lower facial height, a larger gonial angle, and greater SN, palatal, and occlusal planes to mandibular plane angles. All of these measures except gonial angle were also significantly different between the allergic children and the nonconsanguineous controls. Also, the allergic subjects compared with controls had smaller SNB and SN-pogonion angles and an increased overjet. Both allergic and nonallergic sibling groups showed larger mean adenoid size on radiographs than controls. For most variables the nonallergic siblings fell between the allergic children and the control subjects. Overall, the allergic children had longer, more retrusive faces than controls. This retrusive characteristic was present in nonallergic siblings and cannot be ascribed to the apparent breathing mode at the time of the study. These results confirm earlier reports that allergic rhinitis may be associated with altered facial growth. Controlled longitudinal studies to analyze a possible cause-and-effect relationship and the effects of medical and surgical treatments should be undertaken.     

Osteogenic distraction and orthognathic surgery to correct sequelae of ankylosis of the temporomandibular joint: a case report

A 17-year-old female patient presented with sequelae to ankylosis of the temporomandibular joint, which included vertical maxillary protrusion, anterior open bite, labial incompetence, micrognathia, undefined neck angle, facial asymmetry, Class II molar relationship, and Class III canine relationship. She presented with the following cephalometric and soft tissue data: SNA angle = 78 degrees, SNB angle = 70 degrees, incisor-nasion-point A = 11 degrees, incisor-nasion-point B = 33 degrees, Frankfort-mandibular plane angle = 43 degrees, occlusal plane = 25 degrees, subnasale-stomion = 20 mm, stomion superius-stomion inferius = 9 mm, stomion inferius-soft tissue menton = 30 mm, neck angle = 144 degrees, and chin projection = 10 mm. Orthognathic surgery and mandibular osteogenic distraction were employed, specifically Le Fort I osteotomy to decrease a vertical excess of 12 mm, augmentation genioplasty of 17 mm, and bilateral extraoral distractors of bidirectional vector for a 14-mm augmentation of the mandible. The result was satisfactory with minimal adverse complications.     

不同垂直骨面型者的颏部形态

目的探讨不同垂直骨面型者的颏部是否存在形态差异,以及不同垂直骨面型与下颌颏部形态的关系。方法选择未经正畸治疗的80例青少年错!患者为研究对象,年龄（12.69±0.70）岁,根据下颌平面角的大小分为3组：高角组21例,低角组16例,平均角组43例。拍摄X线头颅侧位片,并进行X线头影测量,分别评价患者的矢状骨骼型、垂直骨骼型和颏部形态。采用方差分析比较3组的颏部形态,并对颅面垂直向发育与颏部形态之间进行相关分析。结果高角组的颏高度大于平均角组和低角组（P<0.05）,且高角组颏部更显细长,低角组颏部更显粗短。高角组颏部唇面较低角组更加平直而突度较小（P<0.01）,颏角小于低角组（P<0.05）。下颌平面角与颏高度、颏曲度正相关,而与颏厚度/颏高度、颏角之间存在负相关。结论不同垂直骨面型者之间存在颏部形态差异,既是各结构之间相互补偿和协调的关系,也对正畸矫治设计产生影响。     

Dentofacial growth in patients with Sotos syndrome

Sotos syndrome is an overgrowth syndrome leading to peculiar facial characteristics, large hands and feet, and mental retardation. The maxillofacial characteristics are metopic protrusion, a high and narrow palate and a tapered mandible. In this study, we evaluated changes in maxillofacial growth in 2 patients with cerebral gigantism during the peripubertal period. Patient 1 was a boy aged 8 years at the first examination. The face showed midface retraction and a tapered mandible. Maxillary median diastema with an OJ of 2.5 mm and OB of 1.0 mm was observed, and the molar region showed mandibular mesial occlusion. Radiography revealed a lack of 15, 25, 37, 47, 14, 24, 34 and 44. Cephalometrics demonstrated maxillary and mandibular retrusion with an SNA of 68 degrees and an SNB of 70 degrees , and the patient had leptoprosopia with a mandibular plane of 38.0 degrees . This plane was 45 degrees at the time of re-examination when the patient was 14 years old, showing an increase in the lower facial height and decreases in facial axis and depth. Patient 2 was a boy aged 14 years at the first examination. The face showed mandibular retrusion and tapering. The occlusion was angle class II div. 1, OJ 14 mm, and OB -1 mm. Cephalometrics demonstrated maxillary and mandibular retrusion with an SNA of 74.5 degrees and an SNB of 69.5 degrees , and the patient had leptoprosopia with a mandibular plane of 37.0 degrees . At the time of re-examination, when the patient was 16 years old, the mandibular plane was 42.5 degrees , showing an increase in lower facial height and decreases in facial axis and depth. In this syndrome, excessive facial height without mandibular forward overgrowth is observed. Since the facial height tended to increase by growth during the peripubertal period, maxillofacial vertical growth is considered important in the treatment of this syndrome.     

Bialveolar protrusion in a Zimbabwean sample.

This study was undertaken to assess dentoalveolar relationships in a well-balanced sample of adult black Zimbabweans. Lateral cephalograms of 25 men and 25 women 18 to 38 years of age with Class I occlusions were obtained from the University of Zimbabwe. Twelve angular and 6 linear measurements were analyzed, and men and women were compared with the Student t test. No statistically significant difference was noted between the 2 sexes. The Zimbabwean sample had a low Frankfort-mandibular plane angle (19.6 degrees +/- 5.5 degrees ) with a receding chin as shown by the negative Pog-NB measurement (-0.7 +/- 1.5 mm). Both the maxilla (SNA = 88.5 degrees +/- 4.7 degrees ) and the mandible (SNB = 83.3 degrees +/- 4.4 degrees ) were prognathic, and the ANB difference was large (5.3 degrees +/- 2.7 degrees ). The maxillary incisors were more upright compared with those of white people as measured by the angle of the maxillary incisor to NA line (20.6 degrees +/- 7.7 degrees ), while the mandibular incisors were severely proclined (IMPA = 105.8 degrees +/- 6.0 degrees, L1-Apog = 6.9 degrees +/- 2.7 degrees, L1-NB = 37.6 degrees +/- 4.9 degrees ), and this proclination was considered to be compensatory to the prognathic maxilla.     

Cephalometric norms for saudi adults living in the western region of Saudi Arabia

European-American norms are still used in the orthodontic treatment of Saudi patients, despite the different ethnic backgrounds of Saudis. The aims of this study were to evaluate the cephalometric features of a Saudi population and to establish cephalometric norms for Saudis living in the western region of Saudi Arabia. Seventy lateral cephalometric radiographs of Saudis (32 females and 38 males; aged 18-28 years) with acceptable profiles and Class I dental relationships were traced and analyzed. The mean value, standard deviation, and range of 16 angular and linear variables were calculated. The resulting norms for Saudis were compared with European-American norms using an independent t-test. Male and female groups were also compared using the t-test. Saudis tend to have an increased ANB angle because of retrognathic mandibles and bimaxillary protrusion as compared with European-Americans. Males tend to have more prognathic mandibles than females as indicated by the statistically significant increase in facial angle (P < .05) and SNB angle (P < .05). Although the anterior lower face height was similar in males and females, males tend to have a steeper mandibular plane angle when related to the anterior cranial base than females (P < .05). Saudis have distinct cephalometric features, which should be used as a reference in treating Saudi orthodontic patients.     

A device for mandibular advancement in respiratory disorders of sleep. Clinical study

This study describes the technical steps for the making of a mandibular advancement device for sleep disordered patients (apnea index < 10). In a second part of the study, a group of 21 patients with sleep disordered breathing treated successfully with a mandibular advancement device is compared to a homologous control group. The experimental group showed cephalometric characteristics approaching those seen in patients with sleep apnea syndrome. The mandibular advancement device moved the mandibule forward (SNB angle increases by 1.7 degrees) and downward (mandibular plane angle increases by 3 degrees, which can be related to the 7.4 mm anterior vertical height increase). The hyoid bone adopted a more distant position from the cervical vertebrae. Important individual variations were seen among the patients for the optimal repositioning of the mandible.     

Altered jaw posture and occlusal disruption patterns following mandibular advancement therapy for sleep apnea: a preliminary study of cephalometric predictors

PURPOSE: Reports of irreversible alteration in jaw posture and destructive occlusal contact relationships in individuals using mandibular advancement devices for obstructive sleep apnea are beginning to appear. This study sought cephalometric means of identifying such individuals before commencing therapy. MATERIALS AND METHODS: Cephalograms of 34 obstructive sleep apnea sufferers who had worn mandibular advancement devices for 2 years were compared retrospectively with baseline films taken at commencement of therapy and analyzed for signs of morphologic changes in jaw position and occlusal relationship. In affected patients, two distinct morphologic species of mandibular reposturing became evident: (1) bilateral posterior open bite with destructive incisal attrition; and (2) less destructive intermediate open bite over the premolar and first molar regions. From the observed morphology patterns, gonial angle and maxillary-mandibular plane angle were analyzed as possible vertical cephalometric risk predictors, with newly defined pterygoid advancement proportion (PtAP) as a horizontal predictor. RESULTS: Three patients displayed the posterior open bite pattern and had gonial angles < or = 119 degrees and maxillary-mandibular plane angles < or = 16 degrees, with PtAP values > or = 0.48. Prediction intervals for the five intermediate open bite cases were 118 degrees < or = gonial angle < or = 128 degrees, and 23 degrees < or = maxillary-mandibular plane angle < or = 32 degrees. PtAP values were > or = 0.52. CONCLUSION: Cephalometric analysis can help practitioners identify which apnea patients might be likely to develop irreversible mandibular postural changes from wearing a jaw-repositioning device.     

Relations between anterior disc displacement and maxillomandibular morphology in skeletal anterior open bite with changes to the mandibular condyle

In this study we investigated the relation between anterior disc displacement (ADD) and maxillomandibular morphology in skeletal anterior open bite with changes to the mandibular condyle. Thirty female patients (60 joints) with both conditions were evaluated. Magnetic resonance imaging of the temporomandibular joint (TMJ) was used to diagnose both ADD and changes to the mandibular condyle (erosion, osteophyte, and deformity). The relations among ADD, changes to the mandibular condyle, and maxillomandibular morphology were examined statistically. Changes to the mandibular condyle had a higher score than sym anterior open bite, the deviated side in asymmetric anterior open bite, and the non-deviated side. The score for disc displacement on the non-deviated side was lower than both the sym side and the deviated side. Unilateral changes to the mandibular condyle and unilateral disc displacement were not apparent in sym anterior open bite, but a unilateral non-displaced disc was seen only on the asymmetric side. Mandibular condylar changes were significantly more common on the deviated, than on the non-deviated, side. The SNB angle was significantly smaller, and the ANB, GZN, and SN-mandibular plane angles were significantly larger in sym anterior open bite. Overjet, ANB angle, GZN angle, and SN-MP angle were significantly larger, and the SNB angle was significantly smaller, in the presence of ADD without reduction and mandibular condylar deformity. We conclude that the prevalence of ADD without reduction and changes to the mandibular condyle were related to mandibular asymmetry and mandibular morphology in anterior open bite. This retrospective study suggests that ADD without reduction and mandibular condylar bone changes may be related to the progression of skeletal class II open bite and mandibular asymmetry in cases of skeletal open bite.     

Skeletal Class II patterns in the primary dentition

The aim of this longitudinal cephalometric study was to investigate early characteristics of favorable and unfavorable growth. Two groups of untreated subjects with skeletal Class II pattern were formed on the basis of an ANB angle at least 2.5 degrees above the individual norm, according to J?rvinen, at age 5. The subjects were followed longitudinally until age 12. The favorable growth group (n = 13) consisted of subjects who exhibited a decrease in the individualized ANB angle of at least 1.5 degrees during follow-up. The unfavorable growth group (n = 10) was characterized by an increase in the individualized ANB angle during the growth period from 5 to 12 years. Early characteristics of unfavorable growth included increased mandibular plane angle (measured to the sella-nasion line and the palatal plane, P <.05), increased lower gonial angle (P <.05), and a decreased ratio of posterior-to-anterior face height (P <.05) [corrected]. At the longitudinal follow-up at age 12, the 2 groups showed significant differences in SNB (P <.01) and individualized ANB (P <.01). The improved sagittal jaw relationship in the favorable growth group was the result of changed mandibular position. Morphogenetic posterior rotation seems to occur early in patients with skeletal Class II pattern and unfavorable growth and might be part of an adaptive mechanism compensating for insufficient mandibular growth.     

The influence of mandibular prominence on facial attractiveness

This study examined the attractiveness of facial profiles. One hundred and two social science students (28 males and 74 females) rated the attractiveness of a series of silhouettes with normal, Class II or Class III profiles. A random sequence of 10 images included an image with the Eastman normal SNB value of 78 degrees, and images with SNB values of 2.5, 5, 7.5 and 10 degrees above and below normal. A duplicate image in each sequence was used to assess reproducibility. The participants scored the attractiveness of each image and also indicated whether they would seek treatment if each image was their own profile.The profile with the normal SNB angle of 78 degrees was rated as the most attractive. Attractiveness scores reduced as the mandibular profile diverged from the normal SNB value. The +5 degree profile (SNB = 83 degrees) was rated as significantly more attractive than the -5 degree profile (SNB = 73 degrees; P = 0.004). No other significant differences between the scores for Class II and Class III profile pairs of equal severity were found. At 10 degrees below the normal SNB (Class II), 74 per cent of the sample would elect to have treatment, while 78 per cent would elect to have treatment at 10 degrees above the normal SNB (Class III).