Table 1. Numbers of tested teeth for each animal.
Figure 1. (A-K) LM observations by silver staining. (A and B) At 3 days post capping. B is a higher magnification of the rectangular area in'A'. There is no evidence of a zone of necrotic tissue. As light inflammatory cell infiltrate is observed just below the Ca(OH)2 agent (arrow in'A'). Classic von Korff fibres (arrows in B) are observed. (C and D) At14 days after capping. D is a higher magnification of the rectangular area in C. Interodontoblastic VKFs (arrows in D) extend from the original dentine and connect to central pulpal fibres (CPF). (E and F) At 21 days after capping. F is a higher magnification of the rectangular area in E. The distinct expansion of predentine is observed from the periphery of the exposed area (arrow in E). VKFs (arrow in F) extend from the expanded predentine (PD) and connect to the central pulp fibres. (G-K)At 30 days post capping .H-Kare higher magnifications of the rectangular area h-k in G, respectively. The exposure site is almost completely occluded with a thin layer of a new dentine bridge (arrow in G). At the distant site from the exposure area, VKFs are observed within the newly formed dentine bridge, and reach up to its surface (arrow in H). Although classical von Korff fibres (arrowhead in H) are observed, no VKFs are seen in the pulp. At the periphery of the exposed area, VKFs are observed within the dentine bridge (arrow in I). New tubular dentine (_) without VKF was formed following the initially formed dentine bridge. VKFs extend perpendicularly from the remaining dentine chips (_in J) at the surface of the exposed area (arrow in J), whilst VKFs are randomly arranged beneath the chip-free surface (arrow in K). In this area, some defects were also observed (arrowheads in K). A, C, E, G: _40. B, D, F, H-K: x400.
Figure 2. Immunostaining for type I collagen is detected in the VKF and the central pulp fibres (arrows in A). Immunostaining for type III collagen is hardly detected in the VKF, but slightly detected in the central pulp fibres (arrow in B). Immunostaining for fibronectin is detected in the VKF and the central pulp fibres (arrow in C). No positive reaction was observed in negative control sections reacted with normal rabbit IgG (D). x400.
Figure 3. (A-C) TEM of the periphery of the exposure area at 14 days post capping.
(A) AVKF passing through odontoblastoid cells (OB) consists of two portions: the thick fibrillar portion (Tc) and the thin fibrillar portion (Tn). Both portions are connected to each other at an angle (arrow).
(B) Higher magnification of the thick fibrillar portion. These fibrils are ~240 nm in diameter.
(C) Higher magnification of the thinner fibrillar portion. These fibrils are ~80 nm in diameter.
A: x3000. B and C: x20000.
Figure 4. TEM of the periphery of the exposure area.
(A) At 14 days post capping. Inset shows LM of the corresponding area and VKFs (arrows in inset) are found to pass through odontoblastoid cells (OB) and reach up to the central pulp. VKFs consist of thick fibrillar (Tc) and thin fibrillar (Tn) portions and show a close relationship with central pulp fibroblasts (F) (see arrow).
(B) At 21 days post capping. Inset shows LM of the corresponding area and VKFs (arrows in inset) are embedded in the expanded predentine. AVKF is embedded in the predentine (PD), passing through the odontoblastoid cells (OB), and shows a close relationship with the central pulp fibroblasts (F).
A-B: x2800. All insets x400.
Figure 5. (A) TEM of a site distant from the exposure area at 30 days after capping. Inset shows LM of the corresponding area. Odontoblastoid cells (OB) have well-organized cell processes (_and arrowheads in inset) and begin attaching to each other. VKFs (VKF and arrow in inset) reach up to the cell process of the odontoblastoid cells but do not continue to the central pulp.
(B) TEM of the periphery of the exposure area at 30 days after capping. Inset shows LM of the corresponding area and VKFs (arrows in inset) do not reach up to the odontoblastoid cells (OB). Although matrix fibres of predentine are observed (arrowheads), VKFs are no longer observed near the odontoblastoid cells (OB), A-B: Decalcified sections, x2800.All insets x400.
Figure 6. Composite drawing of the sequence of VKF during early dentine bridge formation. This figure is made from (A) 14-, (B) 21-,(C) 30-day section, at some distance from the exposure area and (D) 30-day section, at the periphery of the exposure area.
(A) The VKF consisting of a thick and a thin fibril portion extends from the original dentine, passes through the odontoblastoid cells, and has a close relationship with the central pulp.
(B) As the predentine expands, the VKF becomes embedded in it.
(C) As odontoblastoid cells differentiate, they begin displaying well-organized cell processes and attaching to each other, and hence the VKF loses its close relationship with the central pulp.
(D) As the formation of dentine bridge advances, the VKF is embedded in the calcified dentine bridge and no longer observed near the odontoblastoid cells.
Birk DE, Trelstad RL (1984) Extracellular compartments in matrix morphogesis: collagen fibril, bundle and lamellar formation by corneal broblasts. Journal of Cell Biology 99, 2024-33.
Bishop MN, Malhotra M, Yoshida S (1991) Interodontoblastic collagen (von Korff fibres) and circumpulpal dentin formation: an ultrathin section study in the cat. American Journal of Anatomy191, 67-73.
Cox CF, Bergenholtz G, FitzgeraldM, Heys DR, Heys RJ, Avery JK (1982) Capping of the dental pulp mechanically exposed to the oral microflora - a 5-week observation of wound healing in the monkey. Journal of Oral Pathology 11, 327-39.
Cox CF, Keall CL, Keall HJ, Ostro E, Bergenholtz G (1987) Biocompatibility of surface-sealed dental materials against exposed pulps. Journal of Prosthetic Dentistry 57,1-8.
Fitzgerald M (1979) Cellular mechanics of dentinal bridge repair using 3H-Thymidine. Journal of Dental Research 58,2198-206.
Furseth R (1971) The fine structure of the odontoblast predentin area in the root. Scandinavian Journal of Dental Research 79, 141-50.
Gomori G (1937) Silver impregnation of reticulum in parafin sections. American Journal of Pathology 13,993-1002.
Hayward AF, Webb BW(1984) Interodontoblastic collagen fibres in the roots of molar teeth of rats. Journal of Anatomy 138, 581-2 (abstract).
Higashi T, Okamoto H (1996) Electron microscopic study on interodontoblastic collagen fibrils in amputated canine dental pulp. Journal of Endodontics 22,116-9.
Kitasako Y, Shibata S, Arakawa M, Cox CF, Tagami J (2000a) A light and transmission microscopic study of mechanically exposed monkey pulps: dynamics of fibre elements during early dentin bridge formation. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontics 89,945-53.
Kitasako Y, Shibata S, Pereira PNR, Tagami J (2000b) Short-term dentin bridging of mechanically exposed pulps capped with adhesive resin systems. Operative Dentistry 25,155-62.
von Korff K (1906) Die entwicklung der zahnbeingrundsubstanz der saugetiere. Archiv Fur Mikroskopischen Anatomie 67,1-17.
Lechner JH, Kalnitsky G (1981) The presence of large amounts of type III collagen in bovine dental pulp and its significance with regard to the mechanism of dentinogenesis. Archives of Oral Biology 26, 265-73.
Lester KS, Boyde A (1968) The question of von Korff fibres in mammalian dentine. Calcified Tissue Research1, 273-87.
Reith EJ (1968) Collagen formation in developing molar teeth of rats. Journal of Ultrastructure Research 21, 383-414.
Salmon JP, Septier D, Goldberg M (1991) Ultrastructure of interodontoblastic fibres in the rat molar. Archives of Oral Biology 36,171-6.
Seux D, Couble ML, Hartmann DJ, Gauthier JP, Magoloire H (1991) Odontoblast-like cytodifferentiation of human dental pulp cells in vitro in the presence of a calcium hydroxide-containing cement. Archives of Oral Biology 36,117-28.
Shibata S, Fukuda K, Suzuki S, Yamashita Y (1997) Immunohistochemistry of collagen types II and X, and enzyme-histochemistry of alkaline phosphatase in the developing condylar cartilage of the fetal mouse mandible. Journal of Anatomy191,561-70.
Shroff B, Thomas HF (1992) Investigation of the role of von Korff fibres during murine dentinogenesis. Journal de Biologie Buccale 20,139-44.
Silva DG, Kalis DG (1972) Ultrastructural studies on the cervical loop and the development of the amelodentinal junction in the cat. Archive of Oral Biology17, 279-89.
Sogaard-Pedersen B, Boye H, Matthiessen ME (1990) Scanning electron microscope observations on collagen fibres in human dentin and pulp. Scandinavian Journal of Dental Research 98,89-95.
Takita K, OhsakiY, Nakata M, Kurisu K (1987) Immunofluorescence localization of type I and type III collagen and fibronectin in mouse dental tissue in late development and during molar eruption. Archives of Oral Biology 32, 273-9.
Tsuzaki M, Yamauchi M, Mechanic GL (1990) Bovine dental pulp collagens: characterization of type III and V collagen. Archives of Oral Biology 35,195-200.
Tziafas D, Alvanou A, Kaidoglou K (1992a) Dentinogenic activity of allogenic plasma fibronectin on dog dental pulp. Journal of Dental Research 71,1189-95.
Tziafas D, Kolokuris I, Alvanou A, Kaidoglou K (1992b) Shortterm dentinogenic response of dog dental pulp tissue after its induction by demineralized or native dentine, or predentine. Archives of Oral Biology 37,119-28.
Veis A (1985) The role of dental pulp - thoughts on the session on pulp repair processes. Journal of Dental Research 64,552-4.
Yoshiba N, Yoshiba K, Iwaku M, Nakamura H, Ozawa H (1994) A confocal laser scanning microscopic study of the immunofluorescent localization of fibronectinin the odontoblast layer of human teeth. Archives of Oral Biology 39,395-400.
Yoshiba K, Yoshiba N, Nakamura H, Iwaku M, Ozawa H (1996) Immunolocalization of fibronectin during reparative dentinogenesis in human teeth after pulp capping with Ca(OH)2. Journal of Dental Research 75,1590-7.