Furcation development of human mandibular first molar teeth

A study was performed to clarify the temporal sequence of bifurcation development in human mandibular first molar teeth and to investigate the development of features of bifurcation morphology previously described in extracted teeth. This report presents the histometric findings from graphically reconstructed teeth at varying stages of development.
Sixteen developing teeth were graphically reconstructed from tracings of serial sections of thirteen grossly and histologically normal human foetuses ranging in post fertilization age from 17 to 38 weeks. Accuracy of reconstruction was tested by retracing and repeated reconstruction and found to be acceptable.
Furcation development began at about 24 weeks post fertilization with the appearance of two epithelial nodes which approximately maintained their position relative to one another at a time when the rest of the developing tooth expanded. These nodes were joined to the epithelial cap by isthmuses of epithelial cells. As furcation development occurs prior to root formation, it should be considered part of crown development. In the area of the developing furcation entrance the buccal isthmus of epithelial cells was narrower mesio-distally than the lingual isthmus. The epithelial nodes and associated isthmuses were located within the ectomesenchymal tissue of the base of the dental papilla.
These findings suggest the embryologic origins of enamel projections into the furcation, the difference in diameter between the buccal and lingual furcation entrances, and the abundance of cementum in the furcation area.
An incomplete epithelial diaphragm, such as has been described in the marmoset, was not observed in any of the specimens examined.     

Furcation topography of the maxillary and mandibular first molars

The objective of the present study was to describe the topography of the furcation area of the maxillary and mandibular first molars. By using a photogrammetric method, the furcation areas of extracted teeth were plotted to obtain 3-dimensional contour maps. By comparing the individual 10 drawings of the maxillary and mandibular first molars, respectively, some morphological characteristics of the furcation areas could be described. Accordingly, the study showed the complexity of the furcation areas with presence of a number of small ridges, peaks and pits forming a mixture of convexities and concavities.     

Combined orthodontic-surgical management of a transmigrated mandibular canine

The presence of an impacted mandibular canine is one of the most difficult challenges that an orthodontist will meet. Orthodontic treatment is planned on an individual basis after thoroughly considering the patient’s overall facial and dentoskeletal characteristics; the duration, risks, and costs of treatment; patient preferences; and the orthodontist’s experience. This article reports an orthodontic treatment of a boy, age 12.9 years, with an impacted mandibular canine in the permanent dentition that was successfully managed. Radiographic analysis indicated a transmigration of the mandibular right canine. The orthodontic treatment plan included extraction of the deciduous right canine followed by surgical exposure and ligation of the permanent canine. Eruption was properly guided, and the correct position of the tooth was achieved. This challenging treatment approach is described in detail, including the mechanics used to align the impacted canine.     

Sclerotic mandibular bone lesion.

A case of a sclerotic mandibular bone lesion interpreted as a true osteoma has been described, along with the differential diagnosis and treatment. Because the radiographic appearance is not specific for any one lesion, microscopic examination is essential to establish the definitive diagnosis.     

Eruption of a permanent mandibular canine in a 5-year-old boy

The premature eruption of a mature mandibular permanent canine is described in a healthy 5-year-old boy with developmental absence of the primary predecessor. The effects of early loss or missing primary teeth on eruption timing of the permanent successors are discussed. The very early maturation of the permanent canine appears to be a unique oddity, and there are no reports in the literature of eruption of this type of secondary tooth at such an early chronological age.