The healing of bone defect in eight adult rabbits was studied. The age range of animals was 5-23 months. The bone defects were made symmetrically in the inferior surface of the mandibles. At the defect site the root surface of continuously erupting mandibular incisors was exposed. On the left side, the bone defect was covered with a local periosteal flap (control side) and on the right side the defect was covered with a free periosteal graft from the tibia (test side). The healing of bone defects and the amount of new bone were studied. The quality of the bone formed was investigated histologically. The findings of this investigation led to the following conclusions: (1) The bone defects healed on both sides. The amount of bone on the control side was identical to that in the anatomical region. On the test side the amount of bone formed was in seven cases two to threefold that formed on the control side. (2) The histological study proved that the bone formed was lamellar bone, being identical on both the control and the test side. (3) The ages of the animals or the length of follow-up time did not affect the amount of new bone, the healing of the defect or the quality of new bone. (4) The eruption of the incisors was symmetrical. In this study the free periosteal graft from the tibia led to better bone formation than the local periosteal flap in the induced bone defects of the tooth-bearing region in the mandible of the adult rabbit.

Age Factors↗

PubMed1980

Oblique facial clefts: case report.

In a material of about 3,600 facial clefts eleven oblique clefts were observed (3.1%). The most frequent types were the medial oro-ocular and naso-ocular clefts and their combinations. There were two atypical cases and one lateral oro-ocular variety. The oblique clefts were frequently associated with other types of clefts and/or more distant anomalies. No genetic chromosomal or environmental factors were found to explain their etiology. Amniotic bands could possibly be thought to be responsible for the severe malformations in two instances. The lacrimal apparatus was always involved to some degree with the exception of a few incomplete forms. In the alveolar arch the cleft seemed to be situated between the medial incisor and the canine.

Adult↗

PubMed1978

Midface deviation due to mandibular fractures. (An experimental study with clinical comparison).

An experimental study was undertaken into the effect of fractures produced in the body of the mandible, the base of the condylar process and the mandibular condyles, on the bones of the middle third of the face using rabbit sucklings. The rabbits were sacrificed when fully grown, when it was found that in all cases the bones of the middle face had deviated to the traumatized side in comparison with the neurocranium. The greatest asymmetry occurred after injuries to the condyles and least following injuries to the body of the mandible. A comparative study on patients past growing age who had had an injury to the condyle before the age of 10 years suggested a similar disturbance of development. The present material, however, was so limited that reliable conclusions could not be drawn.

Animals↗

PubMed1978

A comparative study of gonial angle and growth of the lower third molar in cleft lip and palate. An orthopantomographical study.

In children and young adults with cleft lip and palate, the gonial angle, the angle between the lower second molar and the mandibular plane, the angle between the longitudinal axes of the second and third molars as well as the timing of the development of the third molar were investigated on the right and left side from orthopantomograms. The results were compared with the corresponding results in a noncleft Finnish material. The series consisted of 100 randomly selected subjects aged from 10 to 24 years, 57 males and 43 females. One to three orthopantomograms were available for each subject, totalling 201. The results were examined in a cross-sectional and longitudinal material. The right and left gonial angles were not found to differ in the different cleft groups. Among subjects with cleft lip and palate the gonial angle was found to be larger in the different age groups than the corresponding values in the comparison material. In both materials, the gonial angle was found to decrease between the ages of 10 and 15 years. In males with cleft lip and palate the decrease in this angle, however, continued up to the age of 19. The anterior angle between the longitudinal axis of the lower second molar and the mandibular base line was about 10 degrees larger than in the comparison material, being slightly larger than that in the Angle's Class III occlusion type in the comparison material. When examined by degrees of development the development of the lower third molar was delayed approx. 0.9 years in males and 1.6 years in females compared with the corresponding times in the comparison material.

Adolescent↗

PubMed1977

Bone formation with free periosteum around the root of rabbit tooth.

Explore the source record for details and available documents.

Animals↗

PubMed1975

Effects of topical glucocorticoid medication on collagen biosynthesis in the dental pulp.

The aim of the study was to observe pulpal collagen synthesis in response to trauma and to glucocorticoid medication. The material consisted of 290 rabbit pulps and 76 human premolar pulps. Collagen synthesis was determined by incubating whole pulps in a medium containing [14C]proline, and measuring the formation of [14C]hydroxyproline. The effect of glucocorticoids was studied in vitro using rabbit pulps. Hydrocortisone and dexamethasone inhibited collagen synthesis, whereas prednisolone had no marked effect. Hydrocortisone was found to inhibit the synthesis of [14C]hydroxyproline in neutral salt soluble and insoluble non-dialyzable collagen fractions. [14C]hydroxyproline in the dialyzable fraction was increased, suggesting that hydrocortisone increased collagen degradation. In the human material, premolar pulps were experimentally exposed and then medicated with capping agents. The contralateral teeth were exposed and capped with other capping materials, in some cases they were left as intact controls. The exposure led to an increase in the collagen synthesis as indicated by increased [14C]hydroxyproline formation and elevated protocollagen proline hydroxylase activity in the pulp. This enzyme activity was suppressed in pulps capped with a glucocorticoid paste. In addition, the collagen synthesis rate was lower in pulps treated with another glucocorticoid containing compound, when compared to pulps capped with a calcium hydroxide preparation.

Administration, Topical↗

PubMed1974