Craniofacial adaptations induced by chincup therapy in Class III patients

The purpose of the present study is to examine the effects of an orthopedic force produced by chincup treatment in patients with Class III malocclusion. Anteroposterior maxillary and mandibular changes were examined as were changes in the vertical dimension. Further, the possibility of posterior displacement of temporomandibular joints in treated Class III subjects was evaluated. Serial lateral headfilms of 22 young females (average age, 9 years), who had received chincup therapy were compared with those of 20 skeletal Class III subjects of similar age who received no treatment during the interval studied. A computerized x-y coordinate program was applied to analyze the cephalometric landmarks and measurements. The treated group showed improvement of the skeletal Class III pattern associated with a slight increase (0.8 degrees per year) in SNA and a slight decrease (-0.7 degrees per year) in SNB and also a decreased gonial angle. The distance from the condyle to the chin (Co-Gn or effective mandibular length) increased significantly less in the treated group in comparison with controls. Increases in lower anterior facial height were not different between the treated and untreated groups. In addition, the cranial base angles N-S-Ba and N-S-Ar showed no statistical difference between groups, but these angles tended to increase with time in both groups. Basion and Articulare showed almost the same amount of backward and downward movement in both groups. The results of this study indicate that the primary effect of chincup therapy was in producing a reduction in mandibular growth increments during the period studied. Maxillary growth was not affected during treatment. Further, the results of this study fail to support the hypothesis that chincup appliance significantly induces the posterior displacement of the glenoid fossa.     

Variability and stability in cognitive abilities are largely genetic later in life

Radiographic cephalometry has been used for the assessment of the effects of mandibular rotation and of posterior growth displacement of the temporomandibular joint on the development of the face and on overjet in 43 patients with complete unilateral cleft lip and palate between the ages of 10 and 15 years. Rotation acted mainly on vertical facial measurements and on the position of the lower jaw. The degree of posterior displacement of the temporomandibular joint exerted an influence on the position of the mandible, on the difference between the functional length of the upper and lower jaw, and on the occlusion of incisors. The direction of growth of the mandible as a whole represented the result of a combination of changes produced by the rotation of the jaw and by the degree of posterior displacement of the temporomandibular joint. The most favourable conditions for development were a combination of the neutral type of rotation with a more pronounced posterior displacement of the temporomandibular joint.     

Assessment of symphysis morphology as a predictor of the direction of mandibular growth

The purpose of this study was to determine whether symphysis morphology could be used as a predictor of the direction of mandibular growth and to assess growth changes of the symphysis. Cross-sectional data included lateral cephalometric radiographs of 115 adults (58 women, 57 men) with the longitudinal sample a subset of 62 subjects (30 females, 32 males) at four age groups. The direction of mandibular growth was evaluated with seven cephalometric measurements that included Y-axis, SN to mandibular plane, palatal plane to mandibular plane, gonial angle, sum of saddle, articulare and gonial angles, percentage lower facial height, and posterior/anterior face height. The mandibular symphyseal dimensions studied were height, depth, ratio (height/depth), and angle. Symphysis morphology was found to be associated with the direction of mandibular growth, especially in male subjects with symphysis ratio having the strongest relationship. A mandible with an anterior growth direction was associated with a small height, large depth, small ratio, and large angle of the symphysis. Conversely, a posterior growth direction was associated with a large height, small depth, large ratio, and small angle of the symphysis. Symphysis dimensions continued to change until adulthood with male subjects having a greater and later occurring change compared with female subjects.     

Computerized cephalometric evaluation of orthognathic surgical precision and stability in relation to maxillary superior repositioning combined with mandibular advancement or setback

PURPOSE: A computerized, cephalometric, orthognathic surgical program (TIOPS) was applied in orthognathic surgical simulation, treatment planning, and postoperatively to assess precision and stability of bimaxillary orthognathic surgery. PATIENTS AND METHODS: Forty consecutive patients with dentofacial deformities requiring bimaxillary orthognathic surgery with maxillary superior repositioning combined with mandibular advancement or setback were included. All patients were managed with rigid internal fixation (RIF) of the maxilla and mandible and without maxillomandibular fixation (MMF). Preoperative cephalograms were analyzed and treatment plans produced by computerized surgical simulation. Planned, 5-week postoperative and 1-year postoperative maxillary and mandibular cephalometric-positions were compared. RESULTS: In the mandibular advancement group, the anterior maxilla was placed too far superiorly, with an inaccuracy of 0.4 mm. The posterior maxilla and the anterior mandible were placed in the planned positions. The lower posterior part of the mandibular ramus was placed too far anteriorly, with an inaccuracy of 2.0 mm. However, the mandibular condyles were accurately placed. In the setback group, the anterior maxilla was placed too far superiorly and posteriorly, with a vertical and sagittal inaccuracy of 1.0 mm and 0.7 mm, respectively. The posterior part of the maxilla was placed in a posterior position with an inaccuracy of 1.9 mm. The anterior mandible was placed too far anteriorly with an inaccuracy of 0.9 mm. The lower posterior part of the mandibular ramus was placed in a posterior position with an inaccuracy of 0.9 mm. However, the mandibular condyles were accurately placed. The statistical analysis of the 1-year stability data showed that the maxilla had moved 0.3 mm posteriorly in the advancement group and the lower incisors had moved 0.8 mm superiorly. No other significant positional maxillary or mandibular changes were found. In the setback group, the maxilla had moved 0.5 mm posteriorly, the anterior mandible 0.5 mm anteriorly, and the lower incisors 0.7 mm superiorly. No significant positional changes were seen in the mandibular ramus. CONCLUSION: The TIOPS computerized, cephalometric, orthognathic program is useful in orthognathic surgical simulation, planning, and prediction, and in postoperative evaluation of surgical precision and stability. The simulated treatment plan can be transferred to model surgery and finally to the orthognathic surgical procedures. The results show that this technique yields acceptable postoperative precision and stability.     

Craniofacial and dental characteristics of Silver-Russell syndrome

We found significant differences in a craniometric, cephalometric, and dental study of 19 Silver-Russell syndrome patients (13 without growth hormone treatment) with appropriate controls. Although head circumference was normal for age, head length was increased, while cranial and facial widths and facial heights were reduced. Posterior facial height, posterior cranial base length, cranial base height, and mandibular body size were significantly smaller than in healthy children of the same height. Articulatory speech disorders were common. Enamel defects pointed to an early prenatal insult. Delayed dental age and small mandibular and cranial base dimensions support the possibility of physiological growth hormone deficiency in many Silver-Russell syndrome children; however, facial soft tissue structures were strikingly different from those observed in classical growth hormone deficiency.     

British and West African facial form in ideal occlusion

True lateral cephalometric radiographs of 20 adult male British subjects and 20 Nigerian adult males were collected. All subjects showed an ideal occlusion of the teeth. These radiographs were analysed using a facial polygon joining the points Nasion, Sella, Articulare, Gonion and Menton. Additionally, measurements were made of the axial inclination of the incisor teeth and the distances from the incisal edges and apices of the teeth to the facial plane. Statistical examination of the results using "t" tests revealed that the average British mandible had a longer ramus but shorter body joined at a wider angle than the Negro, that the nasal part of the face was longer on average in the British group and that the incisor teeth, on average, projected further and were inclined further forward in the Nigerian group. A linear discriminant function in only three variables predicted with 100 per cent accuracy membership of the two groups. The three variables were the mandibular body length, the height of the nasal part of the face, and the amount by which the incisal edges of the lower incisor teeth projected beyond the facial plane.     

Comparative study of craniofacial morphology in Japanese and Australian aboriginal populations

A metric study of 71 Japanese and 106 Australian aboriginal precontemporary crania was undertaken using direct measurements and cephalograms. Compared with Australian aboriginals, the Japanese are characterized by smaller cranial length, cranial base length, nasal floor length, palatal length, mandibular dimensions (except symphysis height), facial depth, posterior face height, and facial profile angle and larger cranial breadth and height, maxillary breadth, palatal breadth, anterior face height, and occlusal and mandibular plane angles. These differences confirm the previously described brachycephalic tendency in aboriginals and the dolichocephalic form in the Japanese. The differences are also consistent with the expected functional differences between the Australian aboriginal hunter-gatherer group masticating more resistant food with larger, more anteriorly located, more powerful masseter muscles and the Japanese group masticating less resistant food with correspondingly less robust masticatory musculature. The results highlight the differences in craniofacial morphology between groups with different genetic backgrounds subjected to significantly different environmental influences.     

Treatment of condylar hyperplasia of the mandible using unilateral ramus osteotomies

PURPOSE: The long-term outcome of bilateral and unilateral ramus osteotomies used for the treatment of unilateral condylar hyperplasia of the mandible are evaluated and compared. MATERIALS AND METHODS: Thirteen cases of unilateral condylar hyperplasia of the mandible were surgically treated during a 10-year period from 1985 to 1995. Seven of the patients were treated by bilateral ramus osteotomies alone; six were treated by unilateral ramus osteotomies of the affected side. Unilateral ramus osteotomy was combined with a maxillary Le Fort I procedure in two of the six cases. Preoperative analysis of patients, indications for case selection, and postoperative results relating to facial symmetry, temporomandibular joint (TMJ) pain, occlusion, and stability were compared in the two groups. RESULTS: The postoperative findings and long-term results in both groups of patients were favorable. Symmetry, arch coordination, and occlusion remained stable. TMJ pain and dysfunction were invariably cured postoperatively. Unilateral ramus osteotomies alone, or in combination with maxillary surgery when deemed feasible and applicable by preoperative clinical analysis, was sufficient to restore symmetry and occlusion in dentally compensated cases. CONCLUSIONS: This study shows that patients with unilateral condylar hyperplasia of the mandible and deviation can be treated favorably by unilateral ramus osteotomy of the affected side; bilateral ramus osteotomy did not have any advantage in such cases. In addition, this procedure, combined with a Le Fort I osteotomy of the maxilla, was also effective in restoring occlusal canting and facial symmetry in dentally compensated cases. However, bilateral ramus osteotomy was required in prognathic cases and in cases in which a unilateral procedure would cause excessive rotation of the contralateral condyle.     

Mutation analysis and expression of the mottled gene in the macular mouse model of Menkes disease

OBJECTIVES: The purpose of this study was to evaluate the ability of two different panoramic imaging systems to produce cross-sectional images with accurate vertical dimensions of the posterior mandible. STUDY DESIGN: Three partially edentulous human cadaver mandibles were used for this study. On each mandible, three potential implant sites were arbitrarily identified in an area between the mental foramen and the ascending ramus. Each site was imaged using two different panoramic machines. Using each image, the mandible's outline, cortical thickness, and position of the mandibular canal were traced on clear acetate film. The mandibles were then sectioned at each site to serve as a gold standard. The cadaver sections and tracings (corrected for magnification) were measured, recording the overall mandibular height, distance from the crest of the ridge to the superior aspect of the mandibular canal, and the thickness of the cortical bone at the most inferior aspect of the mandible. RESULTS: There were no significant differences between either of the system's image measures and the gold standard when considering the distance between the crest and the mandibular canal. Differences were noted between the systems measures and the gold standard in the assessment of the cortical bone thickness and the overall mandibular height. CONCLUSIONS: Both imaging systems can be useful for vertical measurements of a potential implant site in the posterior mandible.     

Comparison of morphine and morphine with ketamine for postoperative analgesia

In addition to the patient's history and a thorough clinical investigation, magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) has been introduced to complete the findings for the diagnosis of internal derangement of the TMJ. However, 'dynamic information' is desirable to help us to understand the mechanism of internal derangement. This information is given for example by electronic axiography recording systems. The lack of any ability to assess joint function dynamically in MRI is a point of criticism. Using a computer-driven pseudodynamic MRI system (CINE mode) 'dynamic information' should be now available. In this investigation 21 patients with TMJ disorders were examined using both conventional static MRI and CINE mode. For the diagnosis of an anterior displaced disc with or without reduction in 18 cases (86%) it was only necessary to consider two static MRIs: a closed mouth position and a maximal open mouth position. Comparison showed there was no advantage in using CINE mode. Contrast and resolution of the static MRIs were shown to be better and so additional findings such as joint effusion and disc deformation could be diagnosed on static MRIs with greater certainty. Only in three (14%) cases was the dynamic information from CINE mode useful for the diagnosis of the displacement of the disc.     

Surgical management of temporomandibular joint ankylosis type III by retaining the displaced condyle and disc

PURPOSE: This article proposes a hypothesis regarding the value of saving the fractured condyle and disc in their displaced position in ankylosis type III for optimal temporomandibular joint (TMJ) function and growth, and describes four cases treated in this manner. PATIENTS AND METHODS: Four patients (three females and one male, 9 to 48 years old) with TMJ ankylosis type III of 3 to 8 years' duration, a maximal mouth opening of 15 to 19 mm, and severely limited lateral and protrusive movements were treated. The ankylosed sites were resected, leaving the displaced condyle and disc in their medial position. RESULTS: Fifteen to 60 months after surgery, the patients had a maximal mouth opening of 44 to 50 mm, as well as better contralateral and protrusive movements. In addition, two young patients (9 and 11 years old) showed an improved facial symmetry. CONCLUSIONS: Treatment of patients with type III TMJ ankylosis should involve retention rather than removal of the displaced condyle and disc. The condyle and disc are left untouched in their precarious medial position so as to provide normal function and growth.     

Juvenile chronic arthritis: a cephalometric analysis of the facial skeleton

A retrospective cross-sectional cephalometric investigation was undertaken to examine the facial form of a group of Finnish children with juvenile chronic arthritis (JCA). Following digitization, the radiographs were divided into three age groups, and according to whether or not 'bird-face' deformity was present. From a total of 67 cases (39 females and 28 males) 19 per cent were judged to be 'affected'. Analyses were carried out and the groups compared using t-tests. The mandible was found to be smaller both in ramal height and body length in the affected sample, with reduction in posterior face height being only partly compensated by increase in bony apposition at the angle producing antegonial notching. There was posterior rotation of the mandible with a reduction in angles S-N-B and S-N-Pog, and an increase in the gonial angle, the angle between the mandibular plane and S-N, maxillary, and occlusal planes. The changes in the maxilla were less marked. Although S-N-A was reduced in all three age groups, it was not significantly so. Maxillary length (ANS-PNS) was significantly smaller in the two younger age groups. In the vertical plane maxillary dimensions were reduced in the two younger age groups. A highly significant increase in the occlusal to maxillary planes angle was observed in all groups. There was, however, no difference in S-N to maxillary planes angle, indicating a more steeply inclined occlusal plane due to subnormally erupted maxillary molars. Although the inter-incisal angle was reduced there was no significant difference in the incisor inclinations in relation to the jaws and despite the posterior rotation of the mandible there was no significant increase in size of overjet or in the frequency of anterior open bite.     

Disk displacement of the temporomandibular joint: correlation of magnetic resonance tomography and clinical findings

PURPOSE: To evaluate the value of magnetic resonance imaging (MRI) in symptomatic patients with different degrees of internal derangement. MATERIAL AND METHODS: We prospectively investigated 117 temporomandibular joints (TMJ) of 59 symptomatic patients and 31 asymptomatic volunteers and correlated this with clinical parameters. RESULTS: There was a positive correlation between the degree of internal derangement and deformity of the disc, maximal mouth opening, signal intensity of the posterior band, thickness of the bilaminar zone, proliferative bony changes, size of the condyle and reduced translation movement of the condyle, which in addition moved upward and backward. Patients most often complained of pain which was dependent on the degree of disc displacement and condylar changes. Clinical parameters were found to be inaccurate in predicting disc displacement. CONCLUSION: Patients with internal derangement of the temporomandibular joint may be asymptomatic. Patients history may give the only pointer to the disorder.     

Management of posttraumatic malocclusion caused by condylar process fractures

PURPOSE: The aim of the study was to evaluate the results of orthognathic surgery in cases with posttraumatic malocclusion as a long-term complication of condylar process fractures. PATIENTS AND METHODS: A retrospective study on 21 patients with posttraumatic malocclusions attributable to condylar process fractures was performed. In group I, 15 patients were treated for asymmetric malocclusion with unilateral or bilateral mandibular ramus osteotomies. In group II, six patients were treated for anterior open bit with either a Le Fort I osteotomy (n=5) or a bilateral ramus osteotomy (n=1). All patients had clinical and radiographic follow-up for at least 1 year. RESULTS: Stable dental and cephalometric results were obtained in all patients except the one in group II who was treated with bilateral sagittal split osteotomies. In two cases, both in the asymmetric group, minor occlusal interferences had to be treated by equilibration in the early postoperative period. CONCLUSIONS: Orthognathic surgery is a predictable and stable method for the treatment of posttraumatic malocclusion due to condylar process fractures. Maxillary orthognathic surgery is successful in correcting symmetric anterior open bites due to bilateral condylar process fractures. Because posttraumatic malocclusion is a rare complication after closed treatment of condylar process fractures, and it can be treated satisfactorily using orthognathic surgery, routine open reduction and fixation of condylar process fractures is not indicated to prevent posttraumatic malocclusion.     

Orthognathic surgery: a hierarchy of stability

The stability and predictability of orthognathic surgical procedures varies by the direction of surgical movement, the type of fixation, and the surgical technique employed, largely in that order of importance. The most stable orthognathic procedure is superior repositioning of the maxilla, closely followed by mandibular advancement in patients in whom anterior facial height is maintained or increased. (If facial height is decreased by upward rotation of the chin, stability is compromised). The combination of moving the maxilla upward and the mandible forward is significantly more stable when rigid internal fixation is used in the mandible. Forward movement of the maxilla is reasonably stable, with or without rigid internal fixation, but mandibular setback often is not stable, and downward movement of the maxilla that creates downward rotation of the mandible is unstable. For mandibular setback, the inclination of the ramus at surgery appears to be an important influence on stability. It has been suggested that both interpositional synthetic hydroxyapatite grafting and simultaneous ramus osteotomy improve the stability of downward movement of the maxilla, but this has not been well documented. In two-jaw Class III surgery, the stability of each jaw appears to be quite similar to that of isolated maxillary advancement or mandibular setback. The least stable orthognathic procedure is transverse expansion of the maxilla. Although surgically assisted rapid palatal expansion has been suggested as a more stable alternative to segmental Le Fort I osteotomy, the patterns of movement resulting from the two procedures are different, and differences in stability have not been established.     

A cephalometric analysis of six Twin Block patients. A study of mandibular (body and ramus) growth and development

A study of the effect of the Twin Block appliance on the underdeveloped mandible. Significant growth has been measured cephalometrically and charted on 6 patients, 4 males and 2 females, who have worn the Twin Block for approximately one year. With Pre-Twin Block cephalometric taken, the Twin Block was inserted and bite blocks were advanced approximately every 8 weeks. Progress and Post-Twin Block cephalometric (lateral) radiographs show a significant increase in ramus height and mandibular body length. The purpose of this article is to demonstrate actual mandibular bone growth. A number of the subjects still are in the process of finishing their fixed bracketing phase, and we hope to follow this article with another, demonstrating post Twin Block occlusion and other case finishing factors.     

Correlation between maximum bite force and facial morphology in children

The correlation between maximum bite force and facial morphology was studied in 54 boys, 8 to 16 years old, and 66 girls, 7 to 17 years old. Bite force was measured at the first molars with a miniature bite force recorder. Facial morphology was evaluated on profile cephalograms. In addition, the number of teeth in contact in the intercuspal position was recorded with occlusal foils. In the girls, maximum bite force was correlated with the inclination of the mandible, the size of the gonial angle, and the ratio between posterior and anterior face heights. The correlations implied a large bite force with a small mandibular inclination and gonial angle, a large posterior face height in relation to the anterior face height, and a small bite force with the opposite facial characteristics. These correlations were nonexistent or weaker in boys. In both sexes, bite force was correlated with the number of occlusal contacts. Elimination of the influence of age and occlusal contact in the group of girls by the use of partial correlations reduced the correlation between bite force and facial morphology. A significant correlation with the size of the gonial angle remained, however, and the correlation with mandibular inclination was close to significance. In addition to the correlations found with facial morphology, the study clearly demonstrated the need to take gender and occlusal contacts into consideration in future studies of masticatory muscle function and strength in relation to facial morphology.     

A therapeutic approach using dental implants in an irradiated area. The experiences of the René Huguenin Center

Data of an experimental group of bilateral cleft lip and palate patients (BCLP) who had undergone premaxillary setback at a mean age of 10.2 years were compared with a control group of standard cephalometric values for the white population, and with cephalometric data of BCLP patients from the Oslo Cleft Lip and Palate Archive who did not have premaxillary setback. Cephalometric lateral skull radiographs were taken at a mean age of 16.6 years when most facial growth is completed. Overall, the most marked difference between the two cleft samples was a slightly more concave profile in the experimental BCLP group, mainly due to clockwise rotation of the maxillary plane. Other differences were a longer face and a larger mandible in the experimental group.     

P2u purinoceptor modulation of intracellular Ca2+ in a human lung adenocarcinoma cell line: down-regulation of Ca2+ influx by protein kinase C

The aim of the present investigation was to study the functional alterations in the stomatognathic system following orthodontic-surgical management of skeletal vertical excess problems. The sample comprised 43 patients who received combined orthodontic-surgical treatment including bilateral vertical ramus osteotomy for posterior repositioning and counterclockwise rotation of the mandible (n = 26) or Le Fort I osteotomy for maxillary impaction (n = 17). All subjects were examined within 1 week before operation and 6 months postsurgery. Methods of examination included: (a) evaluation of dysfunction by means of a clinical index, (b) measurement of mandibular range of motion, (c) assessment of the number and intensity of occlusal contacts, and (d) tomographic evaluation of condyle-fossa relationships. The results of the study indicated that postoperatively (a) there was an increase of patients with dysfunction in the mandibular osteotomy group and a decrease of patients with dysfunction in the maxillary osteotomy group; (b) the maximum interincisal opening decreased significantly in the mandibular osteotomy group; (c) there was a significant increase in the number and intensity of occlusal contacts in both groups; and (d) the shortest posterior and anterior interarticular distances increased significantly in the mandibular osteotomy group.