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Biomedical subjects

I Brin

Publications and source records attributed to I Brin.

45 records · Page 3Linked to original sources
PubMed1982

Molar occlusion and mandibular rotation: a longitudinal study.

The human dentition undergoes a process of complex development. Growth of the skeleton, morphology and function of the soft tissues (muscles in particular and airway), space considerations, and other factors influence the development of the dentition. The present study considered two of the factors involved: molar relationship in the sagittal plane and mandibular rotation. Forty-two persons from the Burlington sample were studied to determine whether changes in molar relation between the mean of ages 7 to 12 years were correlated with the rotational growth pattern of the mandible. The sample was divided into forward rotators (FR) and backward rotators (BR), based on the changes in the SN-corpus axis angle over time. The statistically significant difference of 4.04 degrees in change of the SN-CA angle over time, between the FRs and BRs, indicates that this method of characterizing the two different types of growers is useful. It is interesting to note, however, that the FRs and BRs, on an average, initially had the same SN-corpus axis angles. The molar relationship was determined on the basis of the cusp-fossa relationship in the sagittal plane. In the twenty-eight forward rotators and fourteen backward rotators the molar relationship did not change in a predictable fashion. Statistically significant correlations were not found between molar occlusion and growth direction patterns. Also, the SN-corpus-axis angle, at a single point in time, is not a good predictor of whether an individual is going to exhibit a forward or backward mandibular rotational growth pattern. The change in molar occlusion during the process of growth and development is a multifactorial phenomenon and cannot be predicted on the basis of the direction of mandibular growth rotation between the ages of 7 and 12 years.

Cephalometry↗
PubMed1981

Rapid palatal expansion in cats: effect of age on sutural cyclic nucleotides.

Previous experiments indicate that bone cells respond to externally applied stimuli with fluctuations of cyclic nucleotide levels. The objective of this experiment was to study the response of bone at the midpalatal suture to the application of tensile forces in young and old animals, through an examination of the osteoblastic staining pattern for cAMP and cGMP. The midpalatal suture was rapidly expanded for 0, 10, and 15 days, respectively, in three young and three old cats. Fresh, frozen, unfixed, undecalcified maxillae were sectioned transversely and stained immunohistochemically for cAMP and cGMP. The staining intensity for both nucleotides was increased in the osteoblasts of the young treated animals, while in the old animals the osteoblasts were only faintly stained for cAMP and cGMP. These results demonstrate that bone cells of old animals are less responsive to tensile forces than the corresponding cells in young animals.

Age Factors↗
PubMed1981

The influence of premature extractions of primary molars on the ultimate root length of their permanent successors.

Final root length of lower premolars which succeed prematurely--extracted primary molars is shortened. The proposed explanation focuses on a possible accelerated movement of the permanent tooth bud and undue environmental stress following the premature extraction of its deciduous predecessor. The degree of shortening is different in both sexes and depends on the age at which the premature extraction is performed. Girls are more affected than boys, especially in cases in which the premature extractions are performed before the age of eight yr.

Age Factors↗
PubMedDate not supplied

Premature extractions of primary molars and the crown/root ratio of their permanent successors.

The effect of premature extractions of primary molars on further development of their successors was studied. A group of forty-six children with fifty-three unilaterally extracted mandibular primary molars was examined when the successors completed their root development. Radiographs of the successors to the extracted molars and their antimeres, which served as internal controls, were taken using the long-cone technique. Crown and root length and area in cross-section, were measured from tracings of the studied teeth and crown/root ratios were calculated. Significantly (p less than 0.05) larger area ratio in the extraction group was found suggesting a smaller root area. In addition, root foreshortening for the first premolars and diminished root area for the second premolars, both successors to teeth extracted after the age of eight years, were found. Although statistically significant, all of the differences were of no clinical importance.

Bicuspid↗
PubMedDate not supplied

Occlusal disturbances resulting from neglected submerged primary molars.

Several studies indicated that submerged teeth have no long-term effect on occlusal development. Individual cases, however, may present extreme complications. Lack of close supervision, in such instances, may lead to serious consequences. Two cases of negligence (one on the parents' part and the other a consequence of the dentist's carelessness) are presented. The need for a close follow-up of submerged teeth is emphasized, and a rigid periodical recall schedule is suggested.

Ankylosis↗
PubMedDate not supplied

Effects of trauma to the primary incisors on their permanent successors: multidisciplinary treatment.

Dental trauma can often be a factor in developing a malocclusion. Although the prevalence of severely affected permanent teeth following trauma to their predecessors is relatively low, each case may present a variety of sequelae. The purpose of the following report was to present the problems confronting the dentist when treating children after serious injury to their primary incisors. A brief summary of the sequelae of trauma to the primary dentition as found in a longitudinally followed sample, as well as in the representative case of a ten-year-old girl, are presented. The need for prolonged follow-up, originality in the solution, and a multidisciplinary treatment approach are stressed.

Child↗