Possible role of cementoblasts in the resorbant organ of human deciduous teeth during root resorption

Abstract

Human deciduous teeth undergoing physiologic root resorption were extracted and fixed with a mixture of formaldehyde and glutaraldehyde and processed for scanning (SEM) and transmission (TEM) electron microscopy, and for acid (ACPase) and alkaline phosphatase (ALPase) cytochemistry. The resorbant organ, rich in odontoclasts, cementoblasts, fibroblasts, and macrophages, formed prominent resorption lacunae in root dentin. SEM observations of resorption lacunae treated with trypsin solution showed islands of newly-formed cementum matrix in part of the resorbing dentin surfaces. Such cementum consisted of bundles of densely-arranged collagen fibrils and, in part, contained forming cementocytic lacunae and canaliculi. Active cementoblasts adjacent to odontoclasts on resorbing dentin surfaces showed cuboidal outlines and were characterized by the presence of numerous cisterns of rough endoplasmic reticulum, well-developed Golgi complexes, secretion granules, and many mitochondria. They sometimes formed a thin layer of cementoid and/or cementum matrix upon the resorbing dentin surface. These cementoblasts had ACPase-positive lysosomes in the cell bodies and exhibited intense ALPase activity along the plasma membranes of whole cell surfaces. These results suggest that, during root resorption, 1) active cementoblasts are present adjacent to active odontoclasts and 2) these cementoblasts are involved in remodeling the resorbing dentin surfaces.

Cementum‐like tissue deposition on the resorbed enamel surface of human deciduous teeth prior to shedding

“…Thus, some authors considered that these mononuclear cells might scavenge the bone surface at the end of osteoclastic resorption (Heersche, 1978; Tran Van et al, 1982;Everts et al, 2002) and that the cement line/reversal line seen on the resorbed surface might be formed by these mononuclear cells (Heersche, 1978; Tran Van et al, 1982;McKee and Nanci, 1996a;Everts et al, 2002). In the case of tooth resorption, it was also reported that similar kinds of mononuclear cell types, e.g., cementoblast-like cells (Sasaki et al, 1990), machrophage-like cells or fibroblast-like cells (Tanaka et al, 1990;Okamura et al, 1993), and a special class of mononuclear cells (Bosshardt and Schroeder, 1998) were seen lining the resorption surface. In the present study, we also found that numerous mononuclear cells was seen to populate the resorbed enamel surface after the withdrawal of the odontoclasts and prior to the onset of repair cementum-like tissue formation.…”

“…However, tooth resorption occasionally takes place under pathological conditions such as infection, trauma, or tumor development (Andreasen, 1988;Tronstad, 1988). It is well known that after cessation of tooth resorption, the area resorbed is rapidly repaired by the deposition of cementum or cementum-like tissue (Orban, 1928;Mueller, 1931; Kronfeld, 1932;Henry and Weinmann, 1951;Furseth, 1968;Schroeder, 1986;Sasaki et al, 1990;Sahara et al, 1992Sahara et al, , 1993Bosshardt and Schroeder, 1994;Kimura et al, 2003). This site-specific localization of repair seems to resemble that found in bone formation during bone remodeling.…”

“…With regard to tooth resorption and repair, a similar basophilic and electron-dense layer was always found on the resorbed surface of dental matrix as a cement line/reversal line of irregular contour, indicating where resorption had stopped and repair had begun (Furseth, 1968;Schroeder, 1986;Sahara et al, 1993;Sahara, 1998;Yamamoto et al, 2000). To date, however, there is little information available concerning the mechanism of this site-specific repair of tooth tissue that was lost due to odontoclastic resorption (Sasaki et al, 1990;Bosshardt and Schroeder, 1994;Sahara, 1998), mainly because of the infrequency of tooth resorption repair in vivo and the lack of a suitable observation model to examine.…”

Class II MHC Antigen-Expressing Cells in the Pulp Tissue of Human Deciduous Teeth Prior to Shedding.

“…Several research groups reported that the resorbed dentin surface is rapidly covered with cementum-like tissue after the cessation of tooth resorption (FUR-SETH, 1968;SOSKOLNE and BIMSTEIN, 1977;ROLLING, 1981;SASAKI et al, 1990b;SAHARA et al, 1992SAHARA et al, , 1993YAWAKA et al, 1995). SAHARA and SUZUKI (1993) reported on the cellular events during the resorption and repair processes of human deciduous teeth, and pointed out the occurrence of numerous mononuclear cells having many lysosomes and cytoplasmic vesicles reactive for TRACPase and non-specific esterase activities.…”

Preapplication of Orthodontic Forces to the Donor Teeth Affects Periodontal Healing of Transplanted Teeth

“…Thus, the extraction of those teeth with a thinner PDL may also have injured the cementoblasts, which resulted in the inhibition of repair of the root after replantation. 32 On the other hand, Herr et al 33 have reported that fibroblasts originating from both the remaining PDL and alveolar bone compartments functioned to repair the periodontium, but cells migrating to the root surface most likely originated from the PDL. This supports the concept that the PDL attached to the extracted tooth could be another key factor for periodontal healing after replantation or transplantation.…”