Cleft Lip ; surgery ; Cleft Palate ; surgery ; Humans ; Maxillofacial Development ; physiology

OBJECTIVETo investigate the effect of unilateral mastication on glenoid fossae by means of animal experiment.

METHODSAn animal model of unilateral mastication was established by extracting right mandibular molars of Wistar rats. The rats were sacrificed in different period to examine the location changes of glenoid fossae through sagittal and horizontal plane.

RESULTSThe anterior points of glenoid fossae in non-masticatory side of experimental groups were more anterior than those in masticatory sides. The anterior points of the glenoid fossae of non-masticatory sides in experimental groups were more anterior than those of the same sides in the control groups after inducing unilateral mastication for two and four months. After inducing unilateral mastication for two and four months, the anterior and the posterior points of the glenoid fossae of non-masticatory sides in experimental groups became closer to the midline by comparison with masticatory sides as well as the same sides in control groups. Locations of glenoid fossae in masticatory sides showed no changes in comparison with the same side of the control groups.

CONCLUSIONThe forward and inward remodeling of the glenoid fossae can be observed after unilateral mastication was induce to the non-masticatory sides of experimental rats. It is concluded that unilateral mastication might be one of the etiologic factor of temporomandibular joint disorders.

Alveolar Process ; growth & development ; pathology ; Animals ; Facial Asymmetry ; physiopathology ; Female ; Mandible ; growth & development ; pathology ; Mandibular Condyle ; growth & development ; pathology ; Mastication ; physiology ; Maxilla ; growth & development ; Maxillofacial Development ; physiology ; Rats ; Rats, Wistar ; Temporomandibular Joint ; growth & development ; pathology ; Temporomandibular Joint Disc ; physiopathology

Aging/*physiology ; *Biocompatible Materials ; Bone Regeneration/physiology ; Bone Remodeling/physiology ; Facial Bones/physiopathology ; Facial Bones/*surgery ; Maxillofacial Development/*physiology ; *Prostheses and Implants

OBJECTIVETo observe the whole process of cranio-maxillofacial development of an animal model with bilateral premaxillary clefts, after being exerted with premaxillary retro-pressing forces.

METHODSExperimental rabbits with premaxillary clefts and without clefts were exerted with retro-pressing forces respectively. Roentgenographic cephalometric analysis and different investigations of premaxillary suture were performed during the whole craniofacial development.

RESULTSThe longitudinal cephalometric analysis showed that a temporary retarding effect of mid-facial growth existed. The hindrance of maxillary growth potentiality did not occur in spite of being exerted retro-pressing force as to this experimental extent.

CONCLUSIONS(1) Infant rabbit combined with the designed retro-pressing appliance is an ideal experimental model for quantitative study of active orthopedic treatment of protruding premaxilla. (2) Using active preoperative orthopedics to reposit the protruding premaxilla of bilateral cleft palate is a reasonable and effective approach.

Animals ; Cephalometry ; Cleft Lip ; physiopathology ; therapy ; Cleft Palate ; physiopathology ; therapy ; Female ; Maxilla ; growth & development ; Maxillofacial Development ; physiology ; Models, Animal ; Orthodontic Appliances, Removable ; Rabbits

OBJECTIVETo find the laws of vertical growth of craniofacial complex in children with mixed dentition.

METHODS19 female children were annually observed with cephalometric film in 4 successive years, of whom 10 started at 7 years while the others at age of 9. The two groups were longitudinally studied. All data were analyzed by SPSS 8.0 software.

RESULTSIn the observation period, the height of most craniofacial regions continually grew. In anterior face, the middle facial height increased most (increased 4.7 mm from 7 to 10 years old, P < 0.01; increased 3.9 mm from 10 to 12 years old, P < 0.01), while the lower facial height nearly unchanged (increased 1.3 mm from 7 to 10 years old, P > 0.05; increased 1.4 mm from 10 to 12 years old, P > 0.05). Some other regions had their own growing characters.

CONCLUSIONSOnce the occlusal relationships of permanent incisors are established, it is difficult to control the anterior lower facial height with orthodontic treatments.

Cephalometry ; Child ; Child Health Services ; Dental Care ; methods ; Dental Occlusion ; Face ; anatomy & histology ; Female ; Humans ; Longitudinal Studies ; Maxillofacial Development ; physiology ; Skull ; anatomy & histology

We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First, angulation of the upper first molar varied significantly with age and tipped most distally in cases aged <12 years and least distally in cases aged >16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability.
Adolescent ; Adult ; Age Factors ; Anatomic Landmarks ; pathology ; Cephalometry ; methods ; Child ; Cohort Studies ; Dentition, Mixed ; Female ; Humans ; Male ; Malocclusion ; classification ; pathology ; Malocclusion, Angle Class I ; pathology ; Malocclusion, Angle Class II ; pathology ; Malocclusion, Angle Class III ; pathology ; Mandible ; pathology ; Maxilla ; pathology ; Maxillofacial Development ; physiology ; Middle Aged ; Molar ; pathology ; Palate ; pathology ; Retrospective Studies ; Young Adult