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PubMed2001

Prognosis of facial growth in patients with unilateral complete clefts of the lip, alveolus and palate.

AIM: Unfavourable facial growth in patients with cleft lip, alveolus, and palate may occur during puberty. Usually this development is not predictable in a young patient. The aim of the present study was to find an individual growth prediction at an early age that would allow us to decide whether later orthognathic surgery should be included in the treatment plan. MATERIAL AND METHODS: Lateral cephalograms of 41 patients with unilateral clefts of lip, alveolus and palate (uCLAP) with observation intervals of 4 years were computerized, correlations between the variables of the first and second radiograph were calculated and regression equations were established. RESULTS: The skeletal change of the intermaxillary relationship can be explained purely by the lack of midfacial growth. An individual prediction of the angle SNA over a period of 4 years is possible with a correlation coefficient of 0.95. Additional predictions for SNB, Holdaway angle and the index of anterior facial height proportions are demonstrated. CONCLUSION: The prediction procedure elaborated in this paper facilitates the decision at the age of 12 years already, whether or not orthodontic occlusal treatment has been successfully completed at an early age. The alternative is to limit orthodontic treatment to the simple alignment of the two dental arches independently of their intermaxillary relation, and then to correct the facial skeleton and the dental occlusion simultaneously by combining surgical and orthodontic treatment after the completion of growth.

Adolescent↗
PubMed1999

[The architectural balance of the face: a 3D cephalometric concept].

The use of the c2000 software led us to develop a new 3D cephalometric construction, based on the selection on the axial CT Scans of 8 anatomical landmarks and of teeth, all of which were situated along the trigeminal neuro matriciel facial growth axes. The analysis of this construction is based on the use of an original mathematical tool in biology: the axes of inertia. Using the selection of both mental foramen, both infra and supra orbital foramen and the head of both malleus, the C 2000 software creates a geometrical construction called: "the maxillo-facial frame", as well as, a 3D cephalometric analysis: angles, distances, areas, volumes center of gravity and axes of inertia. Using the selection of teeth, the C 2000 software calculates the axes of inertia of each tooth or of groups of teeth. The use of the axes of inertia allow us to create of a hierarchy of anatomical levels the teeth, the half arches, the arches, both arches and the maxillo-facial frame. In addition, for each of these anatomical levels, the axes of inertia create a 3D landmark which allows the calculation of the orientation of each of these elements in relation to the others. The study of 28 orthomorphic people using this analysis revealed the existence of a maxillo-facial balance that is unique for each individual.

Adolescent↗
PubMed1975

Orthodontic and bone grafting procedures in a cleft lip and palate series: an interim cephalometric evaluation.

An attempt is being made to observe the facial and dental development of a cleft lip and palate sample. The study is continuing and, hopefully, offers insight into what happens to these children who have undergone the placement of a dentofacial maxillary orthopedic appliance early at the time of lip closure and an additional surgical procedure and autogenous osteoplasty. Though the final answers to the two previously posed questions are not yet available, we are able to make some value judgments by observing the lateral cephalometric films of these children, and observing their occusion intraorally. Thus far, we are able to state that in our sample, using our treatment procedures in the sequence advocated, we have seen no growth attenuation in the posterior/anterior dimension. The maxilla, at least to the ages observed, does not appear to have been attenuated by our procedures. Further, it would seem that after a limited first phase of orthodontic treatment to align dental units, the degree of crossbite is considerably smaller from that reported in the literature by those using more conventional approaches; thus it is possible that we are doing some good. We are still using these procedures on our newborn and continue to feel that we have a real opportunity to be able to do more orthodontically for these children when they possess a full, permanent dentition and are ready for comprehensive treatment.

Bone Transplantation↗
PubMed1999

Shifts in tooth maturation patterns in non-French Canadian boys.

AIMS: This study was designed to evaluate the predictability of dental maturation patterns in non-French Canadian boys using the maturation curves developed by Demirjian & Goldstein [1]. SAMPLE: Archival cephalometric radiographs taken during a longitudinal study (1930-1960) of Caucasian Americans were re-evaluated. METHODS: Maturation of the permanent teeth on the left side of the mandible was determined according to the methods described by Demirjian & Goldstein. RESULTS: Of the 79 boys studied, 12 (15.2%) started below Demirjian's median and continued as such during the maturation process. Seven (8.9%) started within the second standard deviation above Demirjian's median and continued as such during the maturation process. The remaining 60 boys (75.9%) started below the median of Demirjian's curves at an early age. They matured at a rate that placed them above the median value at the end of the study period. The shift took place before the age of 6 years in 46 (76.6%) cases and between the ages of 6 and 8 years in another nine (15%) cases. In five of the cases which started below Demirjian's median (8.3%) the shift only took place after the age of 9 years. CONCLUSION: The shift from below median to above median value was considered an important factor in treatment planning. The data indicate that there is considerable risk for treatment planning prior to the age of 8 years. The risk is highest when the children are less than 6 years of age due to growth prediction uncertainties.

Canada↗
PubMed1994

Ethanol effects on embryonic craniofacial growth and development: implications for study of the fetal alcohol syndrome.

Fetal alcohol syndrome (FAS), which is brought about by maternal consumption of ethanol during pregnancy, is a major public health problem. To gain understanding of the etiology of this condition, a number of teratological studies have been performed in different animal systems to develop an animal model for FAS. The C57BL/6J mouse strain has been described as susceptible to the teratogenic effects of ethanol, whereas the ICR (CD-1) strain is considered relatively insensitive. We have compared the effects of ethanol on DNA and protein synthesis in cultured embryonic palate mesenchymal cells from both strains to determine if the reported differential sensitivity to ethanol is reflected in differences in ethanol's effects on cell behavior. Chronic exposure to 200 mM ethanol for 48 hr had a strong inhibitory effect on DNA synthesis in palate cells derived from both the C57BL/6J and ICR strains and a significant effect on protein synthesis in C57BL/6J palate cells. When we attempted to verify strain differences in susceptibility to ethanol teratogenesis, we were not able to observe an increased incidence of birth defects due to ethanol in either strain. High doses of ethanol (5.8 g/kg, administered by intraperitoneal injection on gestational day 8) resulted in death in both C57BL/6J and ICR mice. A lower dose (4.8 g/kg) caused decreased fetal weight and increased resorption in both strains, but did not bring about FAS-like craniofacial dysmorphology in either strain. It appears, therefore, that whereas ethanol can significantly affect the behavior of cells derived from craniofacial tissue, these effects cannot be correlated with sensitivity to ethanol teratogenesis in the mouse system.

Animals↗
PubMed1991

A review of the literature on the prevalence of Class III malocclusion and the mandibular prognathic growth hypotheses.

From this review of the literature it appears that we may draw the following conclusions. The incidence of Class III malocclusions is at most 4.2% (Goose et al. 1957, Ast et al. 1965; Knowles 1966, Thylander and Myrberg 1973). The development of various condyle growth hypotheses have lead us to believe that the condyle behaves in a rather unique manner. The condyle does not appear to be an epiphysis, neither does it behave the same as the cranium. It is a unique cartilaginous structure that cannot grow against intermittent or continuous forces (Copray 1985). The cybernetic model as proposed by Petrovic and co workers (1977) that eloquently describes the condyle to be stimulated by a cybernetic switch that connects to the periodontal ligament also does not seem to have much validity. It appears that the lateral pterygoid muscle and the temporo-mandibular condylar frenum have been ascribed capabilities that do not comply to the results of condylotomy studies. Gorette-Nicaise, Awn, and Dhem (1983) as well as the study by Whetten, and Johnston (1985) have shown that neither the absence of the lateral pterygoid muscle nor the physical volumetric expansion of the airway increases condylar growth. It appears that increase in the pressure applied to the condyle could decrease condyle cell proliferation (Armstrong 1961; Thilander 1963; 1965: Janzen and Bluher 1965; Graber 1969; Petrovic 1972; Graber and Muller 1974; Graber 1975;) with resulting growth attenuation. Accordingly, condylar growth is controlled by physical restraint, the absence which leads to incremental growht. The presence of mechanical pressure of adequate duration and magnitude, thus, should limit growth of the young actively growing condyle.

Humans↗
PubMed1998

Effect of X-rays on selenium content in rat jaws.

It is known that X-radiation of the growing jaws results in impaired dental development. We investigated the role of selenium (Se) in radiation-induced dental growth retardation. The heads of 8-day-old female rats were irradiated with a single dose of 9.6 Gy of X-rays. Another group of animals was irradiated under the same conditions but, for radioprotective purposes, were also in deep hypothermia during radiation exposure. Nonirradiated animals served as controls. The Se content in the upper and lower jaws was analyzed by hydride generation atomic absorption spectrophotometry. In the upper jaws of the animals exposed to irradiation, the Se concentration was significantly lower than in those irradiated under conditions of hypothermia (p < 0.05), although both groups showed no significant difference in Se concentration when compared to nonirradiated controls. In the lower jaws, the concentration of Se was significantly reduced in the irradiated group when compared with controls and the rats irradiated under conditions of hypothermia (p < 0.05). There was no significant difference in Se concentration between rats irradiated under conditions of hypothermia and nonirradiated controls. There was no significant change in Se concentration in the jaws of the rats protected by hypothermia during radiation exposure compared with nonirradiated controls. Although Se loss in the irradiated bone could be prevented by hypothermia, we could not prove that Se loss per se is the cause of growth retardation nor that its retention has a radioprotective effect.

Analysis of Variance↗
PubMed2006

Genes, forces, and forms: mechanical aspects of prenatal craniofacial development.

Current knowledge of molecular signaling during craniofacial development is advancing rapidly. We know that cells can respond to mechanical stimuli by biochemical signaling. Thus, the link between mechanical stimuli and gene expression has become a new and important area of the morphological sciences. This field of research seems to be a revival of the old approach of developmental mechanics, which goes back to the embryologists His (1874), Carey (1920), and Blechschmidt (1948). These researchers argued that forces play a fundamental role in tissue differentiation and morphogenesis. They understood morphogenesis as a closed system with living cells as the active part and biological, chemical, and physical laws as the rules. This review reports on linking mechanical aspects of developmental biology with the contemporary knowledge of tissue differentiation. We focus on the formation of cartilage (in relation to pressure), bone (in relation to shearing forces), and muscles (in relation to dilation forces). The cascade of molecules may be triggered by forces, which arise during physical cell and tissue interaction. Detailed morphological knowledge is mandatory to elucidate the exact location and timing of the regions where forces are exerted. Because this finding also holds true for the exact timing and location of signals, more 3D images of the developmental processes are required. Further research is also required to create methods for measuring forces within a tissue. The molecules whose presence and indispensability we are investigating appear to be mediators rather than creators of form.

Animals↗
PubMed1979

Correlation between mandibular retrognathia and induction of cleft palate with 6-aminonicotinamide in the rat.

A single injection of the niacin antimetabolite 6-aminonicotinamide (6-AN) late in gestation produces cleft palate in the rat. In order to achieve an understanding of the mechanism of induction of cleft palate, craniofacial growth and palate development were studied in Sprague-Dawley rats after treatment with 6-AN on day 15 of gestation. The rats were maintained on a high niacin diet (95 ppm) and subjected to three different teratogenic levels of 6-AN. The first group was injected with 8 mg/kg, the second was fasted and injected with 8 mg/kg and the third was treated with 16 mg/kg. The lowest teratogenic dose, 8 mg/kg, produced mild mandibular retrognathia on day 16, delayed shelf elevation a few hours and resulted in small rostral and small caudal clefts of the secondary palate. The moderate dose, 8 mg/kg with fasting, produced more severe mandibular retrognathia, delayed shelf elevation about 24 hours and resulted in 37% full clefts and 63% partial clefts of the palate. The highest teratogenic dose, 16 mg/kg, produced severe mandibular retrognathia, delayed shelf elevation by more than 24 hours and resulted in 100% full clefts of the palate. In each 6-AN group, the most severe mandibular retrognathia was present between days 16 and 17, the critical time for palate closure in the rat. Treatment with 6-AN also produced abnormality of the epithelial cells of the palate, the toothbuds and the nasal septum. Molar and incisor toothbuds were small and malformed, and the epithelial surfaces of the palate and the soft tissue nasal septum did not fuse.

6-Aminonicotinamide↗
PubMed2004

[Therapeutic approach to cleft lip-maxilla-palate: for normal facial growth. A protocol and various technics to restore nasal respiration].

By contrast with the poor maxillary growth following primary surgery in infancy, unoperated adult cleft lip and palate subjects are known to have good facial growth. There is a strong consensus to consider that scarring from primary surgery is the main cause of this problem, particularly scarring from secondary epithelialization of denuded palatal bone, or of closure of the cleft in one layer. In an attempt to improve the outcome of facial growth, a lot of protocols have developed but, currently, none of them appears more valid and the differences between them are more in favor of the personal influence of each surgeon and his team. We are not in agreement with the widely spread opinion attributing the poor results to a severe hypoplasia which could explain the cleft itself. Actually, these patients have a normal potential of growth, but they need normal functions to show it. We think that oral breathing, so frequent among these patients, is enough to explain their poor growth. Over the past 22 years, we have tried to restore, with encouraging results, a nasal breathing mode, as early as 6 years of age, through precise secondary surgery of the nostril and the septum. But with experience, we have concluded that changing the first habit of oral breathing into a nasal one is particularly difficult in cleft patients, and that a nasal mode of breathing should be established once the primary surgery, in order to avoid compensation mechanisms and their consequences. For the last 6 years, our current protocol has allowed to achieve consistently this objective, with an evident influence on the outcome of the growth of the maxilla in complete unilateral and bilateral clefts. A longer follow-up is necessary to confirm it, but henceforth, all those who know the essential role of nasal breathing for a normal facial growth should endorse this process.

Cleft Lip↗
PubMed2004

Developmental fate of the mandibular mesoderm in the lamprey, Lethenteron japonicum: Comparative morphology and development of the gnathostome jaw with special reference to the nature of the trabecula cranii.

The vertebrate jaw is a mandibular-arch derivative, and is regarded as the synapomorphy that defines the gnathostomes. Previous studies (Kuratani et al., Phil. Trans. Roy. Soc. 356:15, 2001; Shigetani et al., Science 296:1319, 2002) have suggested that the oral apparatus of the lamprey is derived from both the mandibular and premandibular regions, and that the jaw has arisen as a secondary narrowing of the oral patterning mechanism into the mandibular-arch domain. The heterotopy theory of jaw evolution states that the lamprey upper lip is a premandibular element, leaving further questions unanswered as to the homology of the trabecula in the lamprey and gnathostomes, and to the morphological nature of the muscles in the upper lip. Using focal injection of vital dyes into the cheek process core of lamprey embryos, we found that the upper lip muscle and trabecula are both derived from mandibular mesoderm. Secondary movement of the muscle primordium is also evident when the expression of the early muscle marker gene, LjMA2, is visualized. A nerve-fiber labeling study revealed that the upper lip muscle-innervating neurons are located in the rostral part of the brain stem, where the trigeminal motor nuclei are not found in gnathostomes. We conclude that the lamprey upper lip is composed of premandibular ectomesenchyme and a lamprey-specific muscle component derived from the mandibular mesoderm innervated by lamprey-specific motoneurons. Furthermore, the lamprey trabecula is most likely equivalent to a mesodermally derived neurocranial element, similar to the parachordal element in gnathostomes, rather than to the neural-crest-derived prechordal element.

Animals↗
PubMed1998

The effect of unilateral partial facial paralysis and muscle ablation on craniofacial growth and development: an experimental study in the rabbit.

The effect of unilateral partial facial nerve ablation and unilateral partial midface muscle ablation on craniofacial growth and development was investigated. New Zealand White rabbits (12 days old) were randomly assigned to three experimental groups: control group, to study normal craniofacial growth and development (n = 15); nerve ablation group, surgically induced unilateral paralysis of the buccal branches of the facial nerve (n = 15); and muscle ablation group, surgical unilateral ablation of the facial muscles innervated by the buccal branches of the facial nerve (n = 12). All animals were operated on at the age of 12 days; follow-up evaluations were performed at the ages of 2 months and 6 months. The age of 2 months represents the endpoint of the prepubertal craniofacial growth and development. At the age of 6 months, the animals are fully grown; therefore, the time period between 2 and 6 months is regarded as the pubertal growth period. Computerized dorsoventral roentgencephalometric (measurement of distances and angles) and computer tomographic (three-dimensional volumetric measurements) investigations were performed at both ages. Additional dry skull measurements were performed to determine more precisely the bone segments involved in the craniofacial growth alterations studied. The obtained results indicated the following. Unilateral partial facial paralysis involving the midface resulted in growth alterations analogous to those seen after unilateral total facial paralysis. The growth alterations were not to be seen as a growth restriction (reduction in bony volume) but as growth misdirections (alterations in shape). Major growth alterations were present in those regions closely related to the facial musculature, namely the nasal, maxillary, and premaxillary regions, resulting in a snout deviation toward the operated side. The growth alterations occurred during prepuberty and remained rather stable during puberty. Morphologic signs of muscle denervation were related to the craniofacial growth disturbances. The growth alterations after unilateral partial facial paralysis were mainly biomechanically induced, as they were analogous to those observed after unilateral midfacial muscle ablation. The fact that after unilateral midfacial muscle ablation at the age of 6 months the severity of the alterations had increased was attributed to the scar formation inherent to the surgical procedure.

Anesthesia↗
PubMed1997

Craniofacial and TMJ effects after glutamate and TRH microsphere implantation in proximity to trigeminal motoneurons of growing rats.

The sequelae of sustained, in vivo delivery of two important neurotransmitter substances, glutamate and thyrotropin-releasing hormone (TRH), upon craniofacial growth and development have previously not been investigated. Our purpose was to document and compare the relative effects of glutamate and TRH microspheres stereotactically placed in proximity to trigeminal motoneurons within the trigeminal motor nucleus. The following null hypotheses were tested: (1) TRH microspheres in proximity to trigeminal motoneurons have no significant effect upon the craniofacial skeleton, and (2) there are no significant differences between the relative effects of chronic, long-term delivery of glutamate and TRH upon the neuromusculoskeletal system of growing rats. Forty male Sprague-Dawley rats were divided into 4 experimental groups (glutamate microspheres, TRH microspheres, blank microspheres, sham surgeries) and underwent stereotactic neurosurgery at 35 days; 5 rats of each group were killed at 14 and 21 days for data collection. Histology revealed that implants were clustered in the pontine reticular formation, close to the ventrolateral tegmental nucleus. Both glutamate and TRH rats had implant-side deviation of their facial skeleton and snout regions; 4 x 2 ANOVA and post hoc t-tests revealed significant (P < or = 0.05, 0.01) differences between groups and sides for motoneuron count, muscle weight, and osteometric data. TRH rats also demonstrated larger implant-side TMJ discs and mandibular fossae in comparison with the other groups. The stated null hypotheses were therefore rejected.

Analysis of Variance↗
PubMed1990

[Expression of c-myc and N-myc in mouse embryos during craniofacial development].

To analyze the role of c- and N-myc on the craniofacial development during the midgestation of mouse embryo, the temprospatial expression in the mandible and the tooth germ was examined by in situ hybridization. In the mandible, c-myc RNA was strongly expressed in the mesenchymal condensation surrounding the ossification center in which a high-level expression of osteopontin was detected with the basal-level expression of c-myc in the corresponding area. In tooth germs, the strong expression of c-myc was detected uniformly in the epithelia of bud stage and then gradually localized in the inner enamel epithelia from cap to bell stages. In contrast, the expression of N-myc was weakly detected in the undifferentiated mesenchymal cells of the dental papilla but was not detected in the regions where c-myc was highly expressed. To study the correlation of myc expression and growth activity, the incorporation of BrdU was examined immunohistochemically. The results revealed that levels of BrdU incorporation were similar between the regions where c-myc was highly expressed and the regions where basal-levels of c- and N-myc expression were detected, suggesting that levels of myc expression are not necessarily correlated to the growth activity. These results indicated that c- and N-myc genes are differentially expressed and further raise the possibility that c- and N-myc may play a major role in differentiation rather than proliferation in the early stage of these organogenesis.

Animals↗
PubMed1983

The quadrilateral analysis: an individualized skeletal assessment.

There must be a change in our approach to orthodontic diagnosis, especially in those cases involving skeletal dysplasias. The orthodontic practice of today requires a more in-depth diagnostic approach before a realistic treatment plan can be developed. An understanding of the problem that exists is emerging as the essential ingredient before appliance therapy can begin. Diagnosis should dictate the direction of treatment for both the orthodontist and the surgeon. A cephalometric analysis should be able not only to detect but to locate the area of the skeletal dysplasia. Surgery, if at all possible, should be performed where the problem exists. In many cases, it becomes rather confusing to determine whether or not surgical orthodontic treatment is indicated, because most of the cephalometric measurements that are used do not reveal whether a skeletal problem exists, its location, or its magnitude. We believe that current cephalometric analyses do not completely recognize the extent of the dysplasia or where it is located within the jaws. Because of this, surgery is performed by repositioning bones to mask the defect rather than to restore a normal balance between the bones of the face. The only recourse the surgeon has is to achieve an acceptable facial profile by relying on cephalometric norms or to make the necessary correction on what appears visually to be an acceptable profile. The quadrilateral analysis offers an individualized cephalometric diagnosis on patients with or without skeletal dysplasias. We believe that it is a reliable and accurate method of assessing whether orthodontic treatment, surgical treatment, or a combination of both is required to achieve a satisfactory result.

Adolescent↗
PubMed1997

A new index for assessing surgical outcome in unilateral cleft lip and palate subjects aged five: reproducibility and validity.

OBJECTIVE: This study assessed the reproducibility, reliability, and predictive validity of a previously developed index by the authors for assessing surgical outcome in unilateral cleft lip and palate (UCLP) children aged 5. METHODS: Sixty randomly selected study models of 5- to 6-year-old complete UCLP subjects were obtained and the index was used to assess their surgical outcomes. RESULTS: Assessment of these study models using the new index demonstrated excellent intra-examiner agreement. The inter-examiner agreement was shown to be good. The corresponding longitudinal models at 16 to 18 years of 54 of the initial 5- to 6-year-old sample were also acquired. These subjects had undergone orthodontic treatment but not orthognathic surgery. The need for osteotomy amongst these models was assessed. Between 13% and 18% (depending on examiner) of 5-year-olds' models were scored in the groups likely to require orthognathic surgery. In the corresponding 16- to 18-year-olds' models, 9% were assessed as likely to benefit from an osteotomy. However, on an individual basis, it was not possible to predict future growth from study models at age 5. CONCLUSIONS: This study has provided a reliable and reproducible index for assessing the outcome of surgery in UCLP subjects earlier than indices already available. True validation of the index was not possible but it appears that it relies on face validity.

Adolescent↗
PubMed1998

Facial volume changes during normal human growth and development.

BACKGROUND: To describe normal soft tissue growth and development of the human face through volume changes and to assess the presence of sexual dimorphism. METHODS: Facial landmark identifications (2,023) were performed on 1,347 healthy Caucasian children and adolescents, ages 6-18 yr, and young adults, ages 19-32 yr. Three-dimensional coordinates of 22 facial landmarks were collected by automated infrared photogrammetry. Facial volumes and selected linear distances and ratios were calculated and averaged for age and sex. RESULTS: Whereas in females in the 14-15 age group, the face had almost completed its growth relative to the adult group, in males a large increase was still to occur, in general agreement with previous reports on craniofacial growth, which suggested a strong tendency in males for growth to continue for several years beyond that seen in females. The male vs. female comparison reflected the different growth patterns. On average, within each age group volumes were significantly larger in males than in females, with some exceptions in the 11-12 age group, where female growth velocity showed a spurt. Sexual dimorphism in facial volume did not appear in different parts of the face to the same extent: a large part of male facial volume preponderance occurred in the lower third of the face. CONCLUSIONS: From 6 yr of age to adulthood, facial soft tissues increased their volumes by >40%, with different growth patterns in boys and girls.

Adolescent↗
PubMed2007

Dental arch widths and mandibular-maxillary base width in Class III malocclusions with low, average and high MP-SN angles.

OBJECTIVE: To analyze the development of the dental arches and skeletal mandibular-maxillary bases in untreated Class III malocclusions with low averages and high mandibular plane angles in subjects aged 10 to 14. MATERIALS AND METHODS: The records of 50 untreated Japanese girls with Class III malocclusions at age 10 were selected from the files of patients pending orthodontic surgery. The patients included those with low (< or =27 degrees), average (27 degrees through 37 degrees) and high (>37 degrees) mandibular plane angles. The maxillary skeletal base width, biantegonial width, and maxillary and mandibular intermolar width were determined on posteroanterior cephalograms obtained at annual intervals when subjects were between 10 and 14 years of age. The difference between the maxillary and mandibular intermolar width was also calculated and reported. RESULTS: All skeletal and dental transverse widths in the high-angle group were significantly smaller than those in the low-angle group (P < .05) from ages 10 to 14. On the other hand, the maxillary to mandibular molar difference was the same for the three groups (P > .05) at each age. The deviations in molar differences did increase from age 10 to age 14 in all three groups. CONCLUSION: Mandibular plane angles might play a stronger role in the transverse skeletal growth of the maxilla and the mandible than the transverse dental growth of the maxilla and the mandible.

Age Factors↗