Remineralization, dentin

RemineraUzation of such affected dentine may not necessarily restore the mechanical function of the original dentine [33]. If the architecture of the remineralized dentine is poor, the resulting tissue will not act as a reinforced structure capable of fulfilling the required biomechanical function [41,42]. There is evidence that remineralized dentine contains larger hydroxyapatite crystallites than unaffected dentine [42] and that the mineral phase crystalUtes are of a different quality from those in native dentine [41]. Achieving sound and useful remineralization in clinical dentistry is thus a difficult task. 

Eidelman, E., Finn, S. B. Koulourides, T. (1965). Remineralization of carious dentin treated with calcium hydroxide. Journal of Dentistry for Children, 32, 218-25. 

The relationship between the degradation of organic matrix and dentin lesion formation has been studied both in vitro and in situ. Several authors employed matrix destruction to assess the role of the matrix in de-and remineralization. For example, Apostolopoulos and Buonocore (1966) reported facilitated demineralization of dentin at pFl<5.5 after treatment with ethylene diamine. Inaba and coworkers (1996) found that removal of matrix from dentin lesions by hypochlorite promotes remineralization, consistent with a larger crystal surface available for mineral deposition after ashing (McCann and Fath, 1958). Flypochlorite-mediat-ed destruction also increases the permeability of mineralized dentin (Barbosa et ah, 1994). 

Modifications of the organic matrix other than degradation have been studied for their effect on dentin de- or remineralization. Glutardialdehyde cross-linking of matrix in dentin lesions inhibits progressive demineralization (Boonstra et al., 1993). Removal of soluble phosphoproteins promotes calcification of demineralized dentin (Clarkson et al., 1991). 

Fusuyama T (1992) Intratubular crystal deposition and remineralization of carious dentin. J Biol Bucc 19, 255-262. 

Inaba D, Ruben J, Takagi O and Arends J (1996) Effect of sodium hypochlorite treatment on remineralization of human root dentine in vitro. Caries Res 30, 218-224. 

Because these products offset mineralization, there has been concern over demineralization of teeth. All manufacturers have addressed this issue and have reported that this has not been a problem, probably because of the positive effect of fluoride on remineralization of dentin and enamel. 

Arends J, Ruben JL, Inaba D Major topics in quantitative microradiography of enamel and dentin R parameter, mineral distribution visualization, and hyper-remineralization. Adv Dent Res 1997 11 403-414. 

Continuing the theme of saliva function, Chapter 3 describes environmental factors that affect the mineralization of hard tissue. The author describes in vitro investigations by himself and others on the relative roles of saliva and plaque fluid, and how the presence or absence of a biofilm affects the efficacy of anticaries agents. Other work focuses on the effects of lesion composition and of lesion proximity to dentine on subsequent enamel de- and remineralization behaviour. The author also discusses the importance of how the characteristics of pre-formed artificial lesions can influence subsequent mineralization behaviour in both in vitro and in situ studies. 

Mineralization is the precipitation of calcium phosphate, but biochemical mediation of this process is not fully understood. In this chapter, the chemistry underlying mineralization (Sect. 1) and the structures ofbones and teeth (Sect. 2) are described. Osteoblasts secrete osteoid matrix and matrix vesicles that transport type I collagen and calcium phosphate, respectively, to the matrix where they will mineralize. Secreted matrix vesicles take up calcium and phosphate until they burst and release the calcium phosphate, which then redissolves and remineralizes around the type I collagen (Sect. 3). Glycoproteins involved in correctly modeling bone and dentin, and the role of osteocalcin in limiting excessive bone growth is then discussed (Sect. 4). There follows a detailed description of enamel (E) mineralization and of the major proteins involved (Sect. 5) followed by two summaries the difference between enamel and bone mineralization, and the vitamins required for mineralization (Sect. 6). 

Several different types of dental caries have been described by clinicians. Specifically these are smooth-surface caries, pit and fissure caries, enamel caries, dentinal caries, secondary caries, early childhood caries and root caries [12], All occur by the same essential mechanism, as described above, and all arise as a consequence of a disturbance to the demineralization-remineralization balance. Attack by organic acids produced by bacteria in the plaque favours demineralization, but the natural remineralization processes of the mouth can reverse this. Certain dietary and hygiene behaviours as well as clinical treatments can enhance this natural remineralization provided they occur early enough in the demineralization part of the process. For example, complexes of casein phosphopeptide with amorphous calcium phosphate have been shown in various studies to be capable of enhancing the remineralization step under certain conditions and in specific groups of individuals [16,17]. These are now available commercially as an anticaries treatment for patients. 

J.M. ten Cate, Remineralization of deep enamel dentine caries lesions, Aust. Dent. J. 53 (2008) 281-285. 

Kinetics of Demineralization and Remineralization of Dentin in Vitro, Trans. Aidr Meeting, Atlanta, GA., 197 co-author D. Boyer... 

Fig. 9.3 TEM images of reconstituted collagen (a) and mineraUzed coUagen using a dual biomimetic analog mineralization protocol (b). TEM images of dentin carious lesion (c) and lesions after 14 days of PILP-assisted remineralization (d). Reproduced with permission from [130] and [132]...

Traditionally remineralization of tooth structures have relied on well established concepts of nucleation and crystal growth. Mineral ions interact with the tooth substrate and crystallization occurs at specific thermodyuamic conditions that are appropriate for formation of an stable apatite phase in register with the preserved tooth structures. Using these approaches, researchers have been able to demonstrate that in carious dentin, the intrafibrillar mineral that is not fully dissolved upon acidic attack may function as nucleation sites for subsequent deposition of calcium and phosphate within the intrafibrillar compartments of collagen fibrils [127]. This, in turn, has been shown to lead to significant increases in the mechanical properties of partially demineralized dentin. 

A recent polymer-assisted biominerlization method that has shown great effectiveness in remineraUzing carious dentin is based on a Polymer Induced Liquid Precursor (PILP) methodology (Fig. 9.3) [132, 133]. The PILP process is based on the action of minute amounts of acidic polypeptides which are added to a remineralization solution. The anionic polymer functions be sequestering... 

Gu, L.S. et al. (2010) Changes in stiffness of resin-infiltrated demineralized dentin after remineralization by a bottom-up biomimetic approach. Acta Biomater., 6 (4), 1453—1461. 

Kawasaki, K. et al. (2000) Relationship between mineral distributions in dentine lesions and subsequent remineralization in vitro. Caries Res., 34 (5), 395-403. 

Zhang, X. et al (2012) Remineralization of partially demineralized dentine substrate based on a biomimetic strategy. /. Mater. Sci. Mater. Med., 23 (3), 733-742. 

Wang, Z. et al. (2011) The dentine remineralization activity of a desensitizing bioactive glass-containing toothpaste ... 

Wang, Z. et al (2011) Dentine remineralization induced by two bioactive glasses developed for air abrasion purposes. J. Dent, 39 (11), 746-756. 

Sauro, S., Thompson, I., and Watson, T.E (2011) Effects of common dental materials used in preventive or operative dentistry on dentin permeability and remineralization. Open Dent, 36 (2), 222-230. 

S., Grass, R.N., Zehnder, M., Imfeld, T. and Stark, W.J. (2007) Remineralization of human dentin using ultraflne bioactive... 

---