Tooth enamel and dentine

Stuart-Williams, H.L.Q. and Schwarcz, HP. 1997 Oxygen isotopic determination of climatic variation using phosphate from beaver bone, tooth enamel, and dentine. Geochimica et Cosmochimica Acta (iV. 2539-2550. 

The invention and development of the zinc polycarboxylate and glass-ionomer cements was brought about by a change in basic attitudes in materials science in dentistry. This largely revolved around the necessity of inventing materials which would adhere to tooth enamel and dentine. 

Wright, L.E. and Schwarcz, H.P. (1999). Correspondence between stable carbon, oxygen and nitrogen isotopes in human tooth enamel and dentine infant diets at Kaminaljuyu. Journal of Archaeological Science 26 1159-1170. 

Buoso, M. C., Fazinic, S., Haque, A. M. I., el al. (1992). Heavy element distribution profiles in archaeological samples of human tooth enamel and dentin using the proton-induced X-ray-emission technique. Nuclear Instruments and Methods in Physics Research B 68 269-272. 

Crosslinked polymers are widely used as dental materials (1-31. Perhaps the most challenging application is in the restoration of teeth (4). The monomers must be non-toxic and capable of rapid polymerization in the presence of oxygen and water. The products should have properties comparable to tooth enamel and dentin and a service life of more than a few years. In current restorative materials such properties are sought using so-called "dental composites" which contain high volume fractions of particulate Inorganic fillers (5-71. However in the present article attention is concentrated on one commonly used crosslinked polymeric component, and on the way in which some of its properties are influenced by low volume fractions of fillers. 

Fig. 11.2. Representative Raman spectra in the fingerprint region of human tooth enamel and dentin. Peak assignments are marked...

Kang, Daniel, D. Amarasiriwardena, and Alan H. Goodman. 2004. Application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to investigate trace metal spatial distributions in human tooth enamel and dentine growth layers and pulp. Analytical and Bioanalytical Chemistry 378 1608-1615. 

Despite these limitations, useful seasonal isotope changes have been identified using tooth enamel and dentin (Koch et al. 1989, 1998 Cerling and Sharp 1996 Fricke and O Neil 1996 Sharp and Cerling 1996 Fricke et al. 1998a,b Kohn et al. 1998, 2003 ... 

The Er YAG laser, emitting at 2.94 p,m near the major water absorption peak (OH stretch), is currently being investigated for ablation of tooth enamel and dentin (Li et al., 1992). 

The corrosive effects of sulfuric acid on teeth with chronic exposure are well established." The damage, etching of dental enamel followed by erosion of enamel and dentine with loss of tooth substance, is limited to tbe parts of the teeth that are exposed to direct impingement of acid mist upon the surface. Although etching typically occurs after years of occupational exposure, in one case exposure to an average of 0.23mg/m for 4 months was sufficient to initiate erosion. ... 

Fluorine is an essential element involved in several enzymatic reactions in various organs, it is present as a trace element in bone mineral, dentine and tooth enamel and is considered as one of the most efficient elements for the prophylaxis and treatment of dental caries. In addition to their direct effect on cell biology, fluoride ions can also modify the physico-chemical properties of materials (solubility, structure and microstructure, surface properties), resulting in indirect biological effects. The biological and physico-chemical roles of fluoride ions are the main reasons for their incorporation in biomaterials, with a pre-eminence for the biological role and often both in conjunction. This chapter focuses on fluoridated bioceramics and related materials, including cements. The specific role of fluorinated polymers and molecules will not be reviewed here. 

As there is no remodelling for enamel and dentine mineral, the incorporation process of fluoride appears in these cases rather different. Two processes have been considered the fluoride uptake during tooth formation and the uptake resulting from saliva and/or topical applications. The fluoridation process of... 

The most common oral condition and dental emergency is dental caries, which is a destructive disease of the hard tissues of the teeth due to bacterial infection with Streptococcus mutans and other bacteria. It is characterized by destruction of enamel and dentine. Dental decay presents as opaque white areas of enamel with grey undertones and in more advanced cases, brownish discoloured cavitations. Dental caries is initially asymptomatic and pain does not occur until the decay impinges on the pulp, and an inflammation develops. Treatment of caries involves removal of the softened and infected hard tissues, sealing of exposed dentines and restoration of the lost tooth structure with porcelain, silver, amalgam, composite plastic, gold etc. 

Those who engage in tooth whitening should be aware that it has a weakening effect on the enamel. This was reported at a meeting of the US Materials Research Society in Boston in November 2005 by Michelle Dickinson who works for Hysitron, an instrument maker based in Minneapolis. This company has developed a piece of equipment capable of measuring the hardness profile of teeth across the enamel and dentine... 

Racemization has recently been found to be an in vivo as well as a diagenetic reaction. We have demonstrated that D-aspartyl residues are accumulating in stable proteins during the human lifetime because of the high mammalian body temperature. Nonturned-over proteins which undergo racemization are tooth enamel (10), dentine (11), and proteins from the nucleus of the lens (12). The extent of aspartic acid racemization in these proteins could be used to calculate the age of the individual. 

Of particular note is the importance of erosion in accelerating tooth wear. The softening of enamel and dentine surfaces by erosive attacks from acid renders the surface extremely susceptible to mechanical attacks [9]. Abfraction is also an example of interaction between wear mechanisms, where abrasion and erosion may act in combination with cyclic loading and unloading to produce an overall wear effect. 

Whilst the use of enamel and dentine as test substrates is widespread, they are complex materials to work with due to the natural variability both within and between specimens. A number of authors have examined alternative materials, which have similar mechanical properties to enamel and dentine, to use as test substrates. Acrylic [19, 20] and synthetic hydroxyapatite [21] have been proposed as suitable materials for abrasion testing, where mechanical effects dominate. These materials have several advantages since they are available as relatively large, smooth samples and exhibit better intra- and inter-sample reproducibility than their natural counterparts. This may, therefore, give better discrimination between test products for formulation development. However, the use of natural enamel and dentine is preferred, particularly for studies that aim to understand interactions between toothpaste products and tooth hard tissues. Other methods for assessing toothpaste abrasivity to hard tissues include gravimetry [22], scanning electron microscopy [23] and laser reflection [24]. 

It should also be recognised that brushing with a toothbrush and toothpaste has significant beneficial effects. In particular, several authors have reported that the presence of a fluoride-rich layer close to the surface of the tooth enamel or dentine has a significant protective effect against erosive and abrasive challenges [60-62],... 

---