The maxillary rotation: Its relation to the cranial base and the mandibular corpus An implant study

A material of 22 patients with metallic implants was used in a longitudinal study, based on lateral head-plates, of the relationship between: 1) the maxillary rotation and the cranial base 2) the maxillary rotation and the different mandibular rotations. No connection has been found between the variation of the maxillary rotation and the growth of the cranial base. The correlation between the maxillary and the mandibular rotations is the highest when the rotation of the corpus is considered. A strong correlation is found between the variation of the condylar growth direction and the variation of the maxillary rotation.     

Evaluation of Class II treatment by cephalometric regional superpositions versus conventional measurements.

INTRODUCTION: The aims of this study were (1) to evaluate cephalometric changes in subjects with Class II Division 1 malocclusion who were treated with headgear (HG) or Fr?nkel function regulator (FR) and (2) to compare findings from regional superpositions of cephalometric structures with those from conventional cephalometric measurements. METHODS: Cephalographs were taken at baseline, after 1 year, and after 2 years of 65 children enrolled in a prospective randomized clinical trial. The spatial location of the landmarks derived from regional superpositions was evaluated in a coordinate system oriented on natural head position. The superpositions included the best anatomic fit of the anterior cranial base, maxillary base, and mandibular structures. RESULTS: Both the HG and the FR were effective in correcting the distoclusion, and they generated enhanced differential growth between the jaws. Differences between cranial and maxillary superpositions regarding mandibular displacement (Point B, pogonion, gnathion, menton) were noted: the HG had a more horizontal vector on maxillary superposition that was also greater (.0001 < P < .05) than the horizontal displacement observed with the FR. This discrepancy appeared to be related to (1) the clockwise (backward) rotation of the palatal and mandibular planes observed with the HG; the palatal plane's rotation, which was transferred through the occlusion to the mandibular plane, was factored out on maxillary superposition; and (2) the interaction between the inclination of the maxillary incisors and the forward movement of the mandible during growth. CONCLUSIONS: Findings from superpositions agreed with conventional angular and linear measurements regarding the basic conclusions for the primary effects of HG and FR. However, the results suggest that inferences of mandibular displacement are more reliable from maxillary than cranial superposition when evaluating occlusal changes during treatment.     

Evaluation of differential growth and orthodontic treatment outcome by regional cephalometric superpositions.

Cephalometric superimposition on cranial base is the accepted method for evaluating mandibular displacement during orthodontic treatment and/or growth. However, assessing mandibular position relative to the maxillary base may yield different information. The aim of this study was to evaluate the effects of regional superpositions (cranial versus maxillary) on interpreting mandibular displacement. Both methods were applied to pre- and posttreatment cephalograms of 22 growing children (12 female, 10 male) treated for Class II Division 1 malocclusion. Differences in linear and angular measurements of three mandibular landmarks (pogonion, gnathion, menton) between cranial and maxillary superpositions were statistically significant (p = 0.0001). Vertical displacement of these landmarks contributed significantly to the differences (p = 0.0001). The contribution of horizontal displacement was not statistically significant. The results support the proposition that, in growing children, posttreatment displacement of mandibular skeletal and dental components should be assessed by both maxillary and cranial base superimpositions. The maxilla is subject to rotational and translational changes during growth that may affect the position of the mandible relative to the maxilla in a way inconsistent with the mandibular displacement perceived upon cranial superposition. Since occlusion is directly associated with the positions of the maxillary and mandibular basal bones, the positions of these bones relative to each other is critical in assessing occlusal changes in individual patients.     

Operational definitions of mandibular morphogenetic and positional rotations.

A material of 30 patients with metallic implants was used in a longitudinal study, based on lateral headplates, of the mandibular rotational pattern. The complexity of the rotational phenomenon in the mandibular rotation has necessitated the proposal of some operational definitions: morphogenetic and positional rotations of the mandible. A relationship has been established between the variation of the gonial angle and the variation of both morphogenetic and positional rotations of the mandible. A relationship has been established between the variation of the condylar growth direction and the variation of both morphogenetc and positional rotations of the mandible: this relationship is the strongest when the morphogenetic rotation of the corpus is considered.     

Maxillary rotation during human growth: annual variation and correlations with mandibular rotation. A metal implant study.

For a longitudinal study of the maxillary rotation, based on lateral headplates, a material of 22 patients with metallic implants in both jaws has been used. It has been established that the degree of maxillary rotation shows variations in direction and in intensity each year. It is smaller, in absolute value, than the degree of mandibular rotation. Due to the fact the direction of the maxillary and mandibular rotations are not always the same, it appears that the interaction between the maxillary and mandibular rotations plays an important role in the vertical and sagittal relationships of both jaws.     

The craniofacial complex in 47, XXX females

A study of the craniofacial complex in four 47, XXX Finnish females, or females with an extra X chromosome, was carried out using cephalometric analysis comprising linear and angular measurements. The lengths of the anterior and posterior cranial bases, the calvarium, mandibular ramus and posterior and upper anterior face heights were found to be significantly shorter than in female controls, while the angles between the foraminal and clival planes, the mandibular plane and cranial base, the maxillary and occlusal planes, the maxillary and mandibular planes and the foraminal and mandibular planes, and also the gonial angle, were significantly enlarged.The present findings of reduced linear measurements, together with the results of studies on the craniofacial complex of 47, XXY and 47, XYY males, suggest dimensional variation between these groups from the promoting effect of an extra Y chromosome and the retarding effect of an extra X chromosome on craniofacial growth.     

Differential growth of the female face in the anteroposterior dimension.

This study contrasts the growth rates of the craniomaxillary and mandibular dimensions. Longitudinal data from lateral head cephalograms of 18 female subjects, between 3 and 18 years old, were used. All of the subjects had yearly cephalograms available and none had received orthodontic treatment. Four linear distances included anterior cranial base, maxillary length and mandibular length and four angular measurements included ANS-S-N, ANS-N-S, Gn-S-N and Gn-N-S. The mandible lagged in size by 4 years relative to anterior cranial base length and by 2 years relative to maxillary length at 5 years of age. There was an incremental gradient of growth from S-N downward to Ar-Pog such that dimensions successively showed a greater relative amount of growth during the entire period of development. The proportional displacement of nasion and anterior nasal spine maintained a constant S-N-ANS angle. The increase in angle S-N-Gn was due to proportionally greater increase in mandibular length relative to anterior displacement of nasion. The different rates of dimensional increments from anterior cranial base to mandible result in differential growth affecting the spatial relationship of maxilla and mandible in the sagittal plane. Skeletal discrepancies in maxillomandibular relationships between 4 and 10 years of age is a normal transient developmental characteristic.     

Operational definitions of mandibular morphogenetic and positional rotations

abstract – A material of 30 patients with metallic implants was used in a longitudinal study, based on lateral headplates, of the mandibular rotational pattern. The complexity of the rotational phenomenon in the mandibular rotation has necessitated the proposal of some operational definitions: morphogenetic and positional rotations of the mandible. A relation-ship has been established between the variation of the gonial angle and the variation of both morphogenetic and positional rotations of the mandible. A relationship has been established between the variation of the condylar growth direction and the variation of both morphogenetic and positional rotations of the mandible: this relationship is the strongest when the morphogenetic rotation of the corpus is considered.     

Maxillary rotation during human growth: Annual variation and correlations with mandibular rotation A metal implant study

For a longitudinal study of the maxillary rotation, based on lateral headplates, a material of 22 patients with metallic implants in both jaws has been used.

It has been established that the degree of maxillary rotation shows variations in direction and in intensity each year. It is smaller, in absolute value, than the degree of mandibular rotation. Due to the fact that the direction of the maxillary and mandibular rotations are not always the same, it appears that the interaction between the maxillary and mandibular rotations plays an important role in the vertical and sagittal relationships of both jaws.     

Balanced facial growth: a schematic interpretation

Balanced facial growth is a complex process that involves maxillary, mandibular, dental, and cranial growth. Growth of the maxilla is due to special movements of translation, rotation, and elongation as well as to growth of its skeletal units and skeletal structures. Growth of the mandible is the sum of growth of all of its skeletal units. Cranial growth influences both maxillary and mandibular positions, which themselves can vary interdependently, in part because of the mutual influences of the maxillary and mandibular dentitions.     

Morphometric investigation in the skulls of young adults. A comparative study between 19th century and modern Italian samples

OBJECTIVE: To test the hypothesis that there are no differences in the shape of the cranial complex between two samples from the same restricted geographical area and separated by almost 150 years. MATERIALS AND METHODS: A group of 35 skulls from the 19th century were selected and compared with a modern sample composed of 43 young adult subjects by means of lateral cephalograms and using a morphometric analysis. The peculiarity of this work is the uniformity of the two samples involving adults coming from the same restricted birthplace and with homogeneity for the orthodontic classification. RESULTS: Although the time spans are short, significant differences were found between the two samples. Shape changes included maxillary elongation toward the posterior region and a marked change in shape configuration in the mandible's points that shows a posterior rotation of the mandibular body. The global result of this cranial base point's movements symbolizes a tiny tendency toward closure of the cranial base angle. CONCLUSIONS: The hypothesis is rejected. Changes were evident, and environmental influences can be responsible for these changes.     

Variation of the range of movement of the mandible in relation to facial morphology in young adults

abstract – Three variables of the range of movement of the mandible, maximal opening capacity, maximal protrusion, and maximal lateral movements were correlated with the morphology of the face as seen in profile radiographs. The material consisted of 101 women with a mean age of 20 years, 8 months. Opening capacity was found to be correlated with the length of the cranial base and the mandible, the sagittal jaw relation, and the inclination of the mandibular ramus and the mandibular base. Protrusion was correlated with the cranial base length, the overjet and overbite, and the inclination of the mandibular ramus. Lateral movement was correlated with the cranial base length, the maxillary protrusion, and the overjet and overbite. Twenty-five to forty per cent of the interindividual variation in range of movement could be explained by interindividual variation in facial morphology. This was less than in a previous investigation of 10-year-old children.     

Studies on Oral Enzymes: VI. Hydrolysis of Periodontal Collagen by Plaque Enzyme Extract

The mandibular line (ML) seems to show stability with both the anterior cranial base (NSI,) and with the Nasal Line (NL) during foetal lifr. The jaw angle, gn—go—co also shows angular stability during the same period. These findings suggest that the lower jaw follows the angular changes found in the cranial base, nasal septum and the upper jaw, the primary factor being possibly the cranial base. There is a reduction in the prognathic development of the lower jaw in the period investigated. Increased lower face prognathism seems to be associated with an anterior rotation of the lower jaw. Lower anterior facial height increases more than upper anterior facial height whereas horizontal growth of the lower face shows less increase than the anterior cranial base, nasal septum and upper jaw. Increased lower face height is followed by a long lower jaw, a large jaw angle and an increased distance between the condyle and NSL. Increase in the sm-NSP distance seems to be associated with a relative anterior position of the condyle, increased length of the mandibular body and inrreased height of the mandibular ramus.     

Surgical mandibular advancement in adolescents: postsurgical growth related to stability.

Ten of 12 adolescents treated with surgical mandibular advancement showed postsurgical mandibular growth, as indicated by an increase in the distance from condylion to pogonion. In all cases, the growth was expressed vertically relative to the cranial base, so that the chin did not come forward. None of the patients had significant increments of anterior maxillary growth postsurgically. Several patients had vertical maxillary growth, which was compensated by vertical mandibular growth, so that the anteroposterior position of the chin was maintained. Forward growth of the maxilla is minimal after the peak of the adolescent growth spurt, and results of mandibular advancement surgery can be acceptably stable after that time.     

Midfacial morphology in adult unoperated complete unilateral cleft lip and palate patients

OBJECTIVE: To examine lateral cephalometric radiographs of adult unoperated cleft lip and palate patients for the purpose of clarifying whether maxillary deficiencies observed in treated cleft patients result from intrinsic defects or surgical intervention early in life. MATERIALS AND METHODS: This retrospective study examined lateral cephalograms of 30 adult patients with nonsyndromic complete unilateral cleft lip and palate (CUCLP). The lateral cephalograms were traced and evaluated for size and position of the cranial base, maxilla, maxillary dentition, mandible, and mandibular dentition as well as for vertical relationships. Comparisons with 30 adult noncleft individuals were made. RESULTS: In unoperated adult cleft lip and palate patients, the cranial base angle was increased with the anterior cranial base reduced in length. The maxilla was found to be normal in size and somewhat prognathic in position. Both the maxillary and mandibular incisors were relatively upright. The mandible was smaller in size and posteriorly positioned. CONCLUSIONS: The potential for normal growth of the maxilla exists in patients with CUCLP. It is likely that disturbances of maxillary growth in surgically operated cleft patients are related primarily to the surgical intervention.     

Craniofacial complex specificities in five men with sex reversal syndrome

In order to clarify the role of sex chromosome constitution in craniofacial growth control, we compared craniofacial morphology of men with sex reversal syndrome (46, XX) with the morphology of normal men, Klinefelter's syndrome and normal women, using cephalometric measurements. Due to physical resemblance between men with 46, XX karyotype and men with 47, XXY karyotype, cephalometric analysis comprised parametres which had already been found to be specific for Klinefelter's syndrome, i.e. cranial base length and flexion, maxillary and mandibular base length, jaw position in relation to cranial base and sagittal jaw relationship. Linear measurements showed reduction of about 10% in maxillary base length in 46, XX men in relation to normal men. Mandibular base in men with sex reversal syndrome was also shortened for about 10% in relation to both normal men and Klinefelter's syndrome. Cranial base flexion in men with Klinefelter's syndrome and in men with sex reversal syndrome showed similarity. The basal angle was found to be more acute, for about 4 degrees , in comparison to individuals with normal karyotype. Unlike in men with Klinefelter's syndrome, mandibular and maxillary prognathism were not registered in men with sex reversal syndrome.     

Orthognathic surgical norms for a sample of Saudi adults: Hard tissue measurements

Objective

The aim of the study is to establish hard tissue cephalometric norms for orthognathic surgery for a sample of Saudi adults.

Materials and methods

Sixty-two lateral cephalometric radiographs for 31 females and 31 males, age range of 22–24 years, were analysed. The mean values of the hard and dental measurements were compared with those of European-American adults using Burstone analysis, as well as comparison between Saudi males and females.

Results

Saudi males had an increased cranial base length, the mandible lied more posterior to maxilla, increased mandibular plane angle and backward rotation of the mandible with less prominent chin, shorter maxillary length, and also less proclination of lower incisors compared to those of European Americans. Saudi females had similar cranial base length and shorter maxillary length than European Americans. In both gender; lower anterior and posterior dental heights were smaller when compared with the European-Americans’ values. A significant difference between Saudi males and females was found. Saudi males showed longer cranial base length, larger vertical skeletal proportion, increased dental values, longer maxillary and mandibular length than the female group.

Conclusion

This study may be useful in providing racially specific cephalometric norms for diagnosis and treatment planning for orthognathic surgery for a sample of Saudi adults.     

Indicators of mandibular dental crowding in the mixed dentition

PURPOSE: Dental crowding occurring in the anterior part of the mandible in the early mixed dentition has been a subject of increasing concern for child patients, their parents, and the pediatric dentist. The aim of this study was to evaluate indicators of crowding found at the primary dentition, which may lead to the future manifestation of crowding at the anterior part of the mandibular arch in the early mixed dentition. METHODS: Skeletal and dental morphological characteristics at the stage of primary dentition were compared between two groups, using dental casts and cephalograms of 23 subjects. These two groups had been formed by evaluating the degree of crowding at 9 years of age (12 normal and 11 crowded cases). RESULTS: The size of several teeth in the crowding group was significantly greater than that found in the normal group. For the cephalometric measurements, a statistically significant difference was found only in the cranial base dimension (S-SE). The stepwise discriminant analysis showed that the mesiodistal size of the maxillary primary canine, the maxillary and mandibular dental arch lengths, and the posterior cranial base length (S-Ba) were effective discriminators in separating the two groups. CONCLUSIONS: It is concluded that larger primary tooth size is the chief indicator in the development of dental crowding. However, the maxillary and mandibular dental arch lengths and the cranial base dimensions, especially that of the posterior cranial base length in the primary dentition, should also be considered as indicators when attempting to predict dental crowding in the early mixed dentition.     

An extra X chromosome effect on craniofacial morphogenesis in men

A comparative study of the craniofacial complex in men with an extra X chromosome, and normal male and female individuals was carried out using cephalometric radiography. The anterior cranial base, anterior and posterior facial height, maxillary base and ascending ramus were found to be significantly decreased in men with Klinefelter syndrome when compared to the male control group. Significant differences in the lengths of mandibular base and posterior cranial base were not found. When compared to the female control, all structures examined were significantly increased, except for the maxillary base.     

Functional orthopedic magnetic appliance (FOMA) III--modus operandi

An intraoral intermaxillary appliance has been developed for the treatment of Class III malocclusions that exhibit midface sagittal deficiency with or without mandibular excess. The functional orthopedic magnetic appliance (FOMA) III consists of upper and lower acrylic plates with a permanent magnet incorporated into each plate. The upper magnet is linked to a retraction screw. The upper magnet is retracted periodically (e.g., monthly) to stimulate maxillary advancement and mandibular retardation. The attractive mode neodymium magnets used in this study produced a horizontal force of 98 gm and a vertical force of 371 gm. Six female Macaca fascicularis monkeys were treated with FOMA IIIs. An additional three animals were treated with sham appliances. After 4 months of treatment, the following results were found: the growth pattern of the cranial base (saddle angle) was not altered; midfacial protraction did occur along a recumbent hyperbolic curve with a horizontal maxillary displacement and an anterosuperior premaxillary rotation; the cumulative protraction of the maxillary complex was initiated at the pterygomaxillary fissure with an additional contribution provided by other circummaxillary sutures (zygomaticomaxillary s., transverse s., premaxillary s.); and inhibition of mandibular length was minimal, but a tendency toward a vertical condylar growth pattern was observed. The interaction between sutural and condylar growth sites appeared biphasic, characterized by an immediate and rapid excitation of the circummaxillary sutures followed by a delayed and slow suppression of the condylar cartilage. Long-term animal and clinical FOMA III studies are recommended.