Ultrastructural and Immunocytochemical Studies of Enamel Tufts in Human Permanent Teeth.

Abstract

Summary. Enamel tufts were exposed after decalcification of the enamel matrix and their fine structures and immunocytochemical characteristics were examined. Under the binocular microscope and the scanning electron microscope (SEM), enamel tufts appeared as corrugated ribbon-like structures located on the dentine parallel to the tooth axis. SEM observation disclosed enamel tufts as bundles of well extended tubular structures with cross striations attributable to hypocalcified enamel sheaths. Plate-like structures were observed at the center of enamel tufts, where they ran parallel to the enamel tufts. Under the transmission electron microscope (TEM), the plates of tufts revealed their origin in the superficial layer of the dentine, penetrating the hypercalcified zone adjacent to the dentineenamel (D-E) junction, and then reaching the tuft region. The plates of tufts ran mainly along the enamel sheaths and partially across the prisms in the tuft region. The protein-A-gold technique revealed an intense immunoreactivity for amelogenin over the superficial layer of the dentine, but over the enamel prisms in the tufts nor over the plates of tufts. The immunoreactivity for 13-17kd protein was detected over the filamentous structures closely associated with the enamel sheaths in the enamel tuft. Thus our study disclosed that enamel tufts consist of both well extended hypocalcified enamel prisms and plates of tufts. The major organic component of the enamel tufts is suggested to be 13-17kd protein rather than amelogenin.

Possible role of DMP1 in dentin mineralization

“…At the same time, some of the structures found at this interface, such as enamel tufts and spindles are poorly understood. These structures are less mineralized and contain more protein than does the surrounding enamel (Amizuka et al , 1992; Palamara et al , 1989). The mineral crystals associated with these structures are much smaller than enamel crystals and similar to those found in dentin (Amizuka et al , 1992; Palamara et al , 1989), at the same time no collagen has been found in these structures.…”

“…These structures are less mineralized and contain more protein than does the surrounding enamel (Amizuka et al , 1992; Palamara et al , 1989). The mineral crystals associated with these structures are much smaller than enamel crystals and similar to those found in dentin (Amizuka et al , 1992; Palamara et al , 1989), at the same time no collagen has been found in these structures. Our in vitro mineralization experiments and earlier reports (Tartaix et al , 2004) demonstrate that DMP1 controls the size of the crystals.…”

The Wear and Tear of Teeth

“…Although such lamellae were long thought to start at the enamel surface and progress as ‘outside-in' cracks [73], experimental evidence now suggests that instead they grow from inside to outside as extensions of enamel tufts [57,58]. There is a forest of tufts all around the enamel-dentine junction ready to pick this strain energy up [74,75]. These cracks grow slowly, requiring a sharply increasing force to extend [57,58].…”

Histomorphometric Evaluation of Organic Enamel Elements in Erupted Bovine Teeth. Part I. Enamel Tufts

“…Both components differ in structure and physical properties. However, no significant evidence has been found so far (1,8).…”