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PubMed1998

Morphologic changes in the upper airway structure following surgical correction of mandibular prognathism.

The purpose of this study was to investigate morphologic changes in oropharyngeal structures in mandibular prognathic patients after orthognathic surgery. The study consisted of 25 patients (12 males and 13 females) with mandibular prognathism who underwent surgical and orthodontic treatment. A set of 4 standardized lateral cephalograms were obtained from each subject preoperatively and at 3 months, 6 months, and 1 year postoperatively. Morphologic changes in upper airway structures were evaluated longitudinally by gender. Parameters of the anteroposterior width of the pharynx significantly decreased at 3 and 6 months in both genders, and these parameters tended to rebound to the preoperative values 1 year postoperatively in females, but not in males. The hyoid bone significantly descended inferiorly 1 year postoperatively in males, while there were no significant changes in females. The distance between the hyoid bone and the third vertebra gradually decreased in males postoperatively; however, there were no significant changes in females. The cross-sectional area of the hypopharynx significantly decreased 1 year postoperatively in males, but not in females. These results indicate that the upper airway morphology changed differently in males and females following surgery. To compensate for skeletal changes following surgery, it appears that males and females responded in different ways to preserve a functional upper airway.

Adult↗
PubMed1976

Early condylectomy to prevent prognathism: a preliminary report.

The effect of bilateral condylectomy in the child with prognathism is described. Reference is made to the anteroposterior growth component of the mandible as measured by peroperative and postoperative cephalometric radiographs. The interruption in the growth of the mandible, coupled with the retropositioning that occurs immediately after the operation, reduces absolute or relative prognathism. Preliminary observation indicates that this prophylaxis does not prevent reformation of the condyle, nor does it result in any clinically discernible change in mandibular movements. Should the condyle reform before body growth is complete, a recommencement of anteroposterior growth in the mandible occurs.

Adolescent↗
PubMed2000

Familial choanal atresia with maxillary hypoplasia, prognathism, and hypodontia.

We report on two sibs and a cousin with bilateral choanal atresia. At 2 months, one sib died of complications following surgical correction of her defects. We evaluated her brother and cousin at age 7 and 9 years, respectively. Both had a tall forehead, maxillary hypoplasia, prognathism, and absence of certain deciduous and permanent teeth. Psychomotor development was appropriate for age. Roentgenocephalometric analyses of several relatives showed that one grandfather of these children and two of the five uncles and aunts also had maxillary hypoplasia and/or prognathism. To our knowledge, this condition has not been described previously and may represent a newly recognized autosomal dominant condition with incomplete penetrance and variable expressivity caused by a defect of neural crest development.

Adult↗
PubMed2002

Thin-plate spline graphical analysis of the mandible in mandibular prognathism.

The chin cup has been used to treat skeletal mandibular prognathism in growing patients for 200 years. The pull on the orthopedic-force chin cup is oriented along a line from the mandibular symphysis to the mandibular condyle. Various levels of success have been reported with this restraining device. The vertical chin cup produces strong vertical compression stress on the maxillary molar regions when the direction of traction is 20 degrees more vertical than the chin-condyle line. This treatment strategy may prevent relapse due to counter-clockwise rotation of the mandible. In this report, we describe a new strategy for using chin-cup therapy involving thin-plate spline (TPS) analysis of lateral cephalometric roentgenograms to visualize transformation of the mandible. The actual sites of mandibular skeletal change are not detectable with conventional cephalometric analysis. A case of mandibular prognathism treated with a chin cup and a case of dental Class III malocclusion without orthodontic treatment are described. The case analysis illustrates that specific patterns of mandibular transformation are associated with Class III malocclusion with or without orthopedic therapy, and that visualization of these deformations is feasible using TPS graphical analysis.

Cephalometry↗
PubMed2004

Vertical ramus osteotomy for treatment of mandibular prognathism.

Following a brief literature review of treatment modalities for mandibular prognathism the authors propose a simplified method for vertical ramus osteotomy. The method was successfully used in 24 patients with mandibular prognathism (alone or in combination with open bite). Postoperative complications (suppuration of the operative wound) were found in 2 patients (8%), and postoperative recurrences--in 5 patients (20.8%). No complications, usually associated with sagittal and vertical intraoral osteotomies (hypoesthesia of the trigeminal nerve, Frey's syndrome, dissecting aneurysm of the internal carotid artery) were found to be consequential to the proposed method.

Adult↗
PubMedDate not supplied

Cranial base angulation and prognathism related to cranial and general skeletal maturation in human fetuses.

The purpose of the present study was to describe normal midsagittal craniofacial morphology in second trimester human fetuses. Measurements of the cranial base angle and the prognathism of the maxilla and the mandible were performed on radiographs of cranial midsagittal tissue blocks of 52 fetuses with a gestational age from 13 to 27 weeks. Special procedures were developed for the definitions of the nasion and sella reference points on the radiographs in the early stages of fetal development. Mean data were reported for stages of crown rump length (CRL) and maturation of the fetal cranial base (MSS), usable as reference in assessment of pathological fetal crania in reports and autopsy procedures. Regression equations were determined for the regression of the angular values on CRL, MSS, and general skeletal maturation (TNO). The cranial base angle was found to decrease significantly, and the angles of prognathism to increase significantly with increasing CRL, TNO, and MSS values. It was suggested that these simultaneous and similar changes in the three angles could be accounted for by the upwards movement of the sella point produced by a cranial displacement of the pituitary fossa caused by local cartilagenous growth and bony remodelling during the period of study. The study thus reflects the influence of cranial skeletal maturation on the early development in shape of the craniofacial complex.

Cephalometry↗
PubMed1991

[The morphology of the base of the cranium in prognathism. A cephalometric study of adult patients].

The cranial base of 60 adults affected by mandibular prognathism was studied with the aid of a computerized cephalometric analysis. The means and standard deviations of the values measured on the sample where compared with the cephalometric standards of the University of Michigan. The studied sample showed a significant reduction in length of the floor of the anterior cranial fossa, the cranial base angle showed no deviation from the control but the whole cranial base was backward and upward rotated in relation to the Frankfurt plane. The cranial base morphology was similar in patients with or without maxillary retrusion. The data in our possession may indicate that mid-facial sagittal growth in patients affected by mandibular prognathism is somehow impaired by altered cranial base growth. In any case the sagittal projection of the frontal and nasal bones appears to be reduced in our patients and this data must be kept in mind when studying these patients with the aid of cephalometry.

Adult↗
PubMed1990

[The study of the relationships between the masticatory muscles activity and the craniofacial morphology in mandibular prognathism].

Facial asymmetry is usually manifested in mandibular prognathism. This is probably because of the intervention of masticatory muscles in some way or another. Functional factors of masticatory muscles are also believed to be responsible for the relapse of facial disharmony even after surgical orthodontic treatment. In the present study, cephalometric analysis was made on a total of 43 patients with mandibular prognathism. The functional activity of their masticatory muscles was measured quantitatively by using electromyography. The data thus obtained were analyzed with respect to their bearings on the morphological points of reference given on posteroanterior cephalogram. Our findings are as follows: 1) At the time of maximal clenching with a bite splint, differences in the activity of left and right masseter muscles had a significantly positive correlation with the deviations from the point Menton on the frontal image, and a significantly negative correlation with the angles of the mandibular ramus to the median line on the frontal view. However, no relation was established between the activity of the masseter muscles and that of the temporal muscles on either side. 2) At the time of maximal clenching in central occlusion, differences in the activities of the masseter muscles on both sides were significantly and positively correlated with the deviations from the point Menton on the frontal image, and significantly and negatively correlated with the angles of the mandibular ramus to the median line. Also a negative correlation was noted between the differences in the activity of temporal muscles on both sides and the deviations from the point Menton. 3) These results suggest that the larger the deflection of the mandible, the larger the activity of the masseter muscle on the deflective side.

Cephalometry↗
PubMed1990

[Two case reports of maxillary prognathism. Some considerations of treatment for different facial type cases].

Generally, prognathism has been just identified as a large overjet. However, for the purposes of treatment, it should be noticed that different facial types are included in this malocclution. Facial pattern is classified into 2 groups; dolico and brachio facial types. The dolico facial type is generally a high angle case. It has a weaker natural anchorage than the brachio facial type. Consequently, it has a downward component in its mandibular growth. The classification of the two different facial types of maxillary prognathism would influence orthodontic treatment. When deciding on the treatment, the differences between the two facial types--in type of anchorage, growth direction, and control of toothaxis--should be taken into account.

Cephalometry↗
PubMedDate not supplied

[The results of using extraoral traction in children with a prognathic bite].

Primary and repeated lateral teleroentgenograms of the head of 37 children aged 4-8 with prognathic occlusion were analyzed, recorded on an average in 2 years after employment of a chin sling with extraoral traction. Analysis has shown normalization of the jaws and occlusion in the sagittal plane, resultant from limitation of mesial transposition of the mandible in the skull in the course of facial skeleton growth. This has been achieved at the expense of inhibition of longitudinal growth of the mandibular body and ascending branches more than twofold as against the reference values and was also a result of mandibular shift due to traction and of enhanced vertical transposition of the mandible in the skull due to distal rotation. The principal indications for the employment of chin sling in the management of prognathic occlusion are intensive growth of the mandible or a tendency to such growth, mesial position of the mandible in the skull, and a combination of these disorders, that may be the principal or additional factors contributing to the pathogenesis of this abnormality.

Cephalometry↗
PubMed1990

Positioning and mobility of the mandibular condyle after surgical correction of the asymmetric, prognathic mandible.

Following the extraoral vertical subcondylar osteotomy in the correction of the highly asymmetric and prognathic mandible, only insignificant radiographic changes were observed in the temporomandibular joint 12 months postoperatively. Slight morphologic alterations of the condylar seating were demonstrated at occlusion, but there was no significant difference in condylar position between the two sides of the surgically corrected asymmetric mandible. The condylar axis did not deviate from the preoperative situation, and condylar axis did not deviate from the preoperative situation, and condylar mobility was fully resumed 12 months postoperatively. The extraoral vertical subcondylar osteotomy procedure is applicable in the treatment of combined mandibular asymmetry and prognathism and does not create morphologic changes that differ in the two temporomandibular joints.

Adolescent↗
PubMed1989

[Correction of mandibular prognathism by intraoral vertical ramus osteotomy and improvement of the technic].

A new procedure, intraoral vertical ramus osteotomy (IVRO) becomes more and more popular in correction of mandibular prognathism recently. Simplified operation, decreased bleeding and mild reaction after operation are the advantages of this procedure. 32 cases of mandibular prognathism corrected by intraoral vertical ramus osteotomy were reported in this paper. Modifications for avoiding fracture and displacement of proximal segment, the main complication and indications of IVRO were discussed.

Adult↗
PubMedDate not supplied

[Facial prognathism and its relation to the cranial base in Brazilian children with Class I malocclusion].

The objective of this work was to study the degree of the facial prognathism, considering the relationships between the SNA and SNB angles with the saddle angle (NSAr and NSBa). The sample consisted of eighty cephalometric roentgenograms, taken in lateral norm, of Brazilian white children, forty boys and forty girls, with both dental and skeletal, class I malocclusions, with ages between 9 years and 2 months old and 13 years and 7 months old. Data were statistically analysed and the sample was divided in three groups considering the mean value and the standard deviation of the NSAr angle. Sixteen subjects (seven boys and nine girls, 20 percent of the sample) presented an NSAr angle that was smaller than 119.5 degrees (x - 1s); twenty subjects (forteen boys and six girls, 25 percent of the sample), showed an NSAr angle more than 127.5 degrees (x + 1s) and forty-four subjects (nineteen boys and twenty-five girls, 55 percent of the sample) had an NSAr angle value between 119.5 and 127.5 degrees (x +/- 1s). The results led to the following conclusions: 1. There is a negative correlation, statistically significant between the saddle angle (NSAr and NSBa) with the SNA angle in subjects with class I malocclusions. An NSAr or NSBa angle higher than the mean value plus one standard deviation, it is associated with of the maxilla retrognathism and contrariwise. 2. There is a negative correlation, statistically significant between the sadle angle (NSAr and NSBa) with the SNB angle in subjects with malocclusions. An NSAr or NSBa angle higher than the mean value plus one standard deviation, it is associated with the mandible retrognathism and contrariwise. 3. The normal values of the SNA and SNB angles for an individual and the degree of the facial prognathism should be determined individually, since that the values of these angles might be affected for cranial base morphology.

Adolescent↗
PubMed1978

Inverted-L osteotomy for correction of mandibular prognathism after relapse.

As more orthognathic surgery is performed, more case of relapse can be expected. A case of re-operation of a recurrent prognathism has been reported. An alternative surgical approach was used because the planned operation could not be accomplished. However, the implications of the use of the technique are broader than the single example given in this report. The inverted-L technique, because of its similarity to the combined oblique osteotomy and coronoidectomy for correction of extreme prognathism, provides an alternative procedure that leaves a greater proportion of the masticatory musculature in its natural position. In addition, with the development of techniques and instrumentation for intraoral approaches to oblique osteotomy of the ramus, the feasibility of an intraoral inverted-L osteotomy becomes apparent and the approach merits further consideration.

Adult↗
PubMed1978

Sliding osteotomy in the mandibular body for correction of prognathism.

To overcome some of the disadvantages of the mandibular body ostectomy, a sliding osteotomy accomplished by parallel sectionings of the mandible in the regions of the first premolars was used for the treatment of mandibular prognathism in two cases. The osteotomy was performed by an intraoral approach without any damage to the contents of the mental foramen. The anterior segment could be moved back to any desirable position without losing optimum bony contact. An adequate blood supply to the anterior segment was maintained by a large area of periosteal attachment on the lingual side. The method is effective for correction of mandibular prognathism in which a good occlusion cannot be expected by a ramus osteotomy.

Adolescent↗
PubMed1979

Surgical treatment of mandibular prognathism--a review of 25 cases.

Mandibular prognathism is a common developmental jaw deformity with functional disabilities and facial disfigurement, characterised by a prominent mandible. Very satisfying cosmetic and functional results can be achieved by surgery and the literature is replete with surgical techniques for correcting this deformity. This paper discusses the surgical treatment of mandibular prognathism and reviews a series of 25 consecutive patients treated by an extra-oral technique known as Subsigmoid Oblique Osteotomy (Vertical Subcondylar Osteotomy) during a seven-year period, (1969-76).

Adolescent↗
PubMed1994

Midface prognathism in maxillonasal dysplasia (Binder's syndrome) determined by a theoretical midface ratio.

A theoretical midface ratio was determined from midface lengths and heights in straight lateral radiographs. Using regression analyses, the ratio was tested on 90 adults who did not have an aberrant anatomy of the maxilla. A linear relationship was found between the theoretical midface ratio and sella-nasion-point A (SNA), and the correlation was high (adjusted R2 = 82.7%). Limit values were determined using the theoretical midface ratio for the classifications of retrognathia, orthognathia, and prognathia. Conditional probabilities were estimated for classifications according to SNA for every classification by the theoretical midface ratio. Eighty percent of the subjects were identically classified by SNA and the theoretical midface ratio, and no subjects were placed differently in the extreme groups of retrognathia and prognathia. The theoretical midface ratio was then used to estimate the degree of prognathism in 35 adults with maxillonasal dysplasia. Less than half of the subjects had maxillary retrognathia, and the majority had an orthognathic or even prognathic maxilla. This is an indication that individualization of treatment objectives, including the consideration of mandibular setback operations to correct incisor crossbites, is equally important in maxillonasal dysplasia and in normal anatomy.

Adolescent↗
PubMed1995

[Evaluation of presurgical orthodontic correction of the mandibular prognathism].

The aim of this study was to evaluate the effects of presurgical orthodontic correction of the mandibular prognathism. The sample consisted of two groups of surgical cases. The cases of the mandibular prognathism in group I with lower anterior dental compensation received presurgical orthodontic decompensation, and the cases in group II without lower anterior dental compensation did not receive presurgical orthodontic decompensation. The results showed that before presurgical orthodontic treatment, significantly differences existed between the two groups variable ILi/OL and ANB. After presurgical orthodontic correction lower incisors position in group I was very close to that in the group II, this means that the presurgical orthodontic treatment significantly changed the position of the lower incisors.

Adolescent↗