In Situ Models,Physico-Chemical Aspects

Abstract

In situ (intra-oral) caries models are used for two purposes. First, they provide information about oral physiological processes. Such information helps to detail our knowledge of the oral ecosystem and to verify conclusions from in vitro experiments. Second, in situ models are utilized to test preventive agents in the phase between laboratory testing and clinical trials. Most investigations involving enamel inserts have been aimed at testing new dentifrices. The experimental designs of such studies usually do not allow one to draw conclusions on physico-chemical processes, e.g., because of single point measurements. Studies of model parameters (lesion type, lesion severity, and de/remineralization in time) constitute only a minority of the research reports. The most striking observation obtained with in situ models has been the significant differences in de/remineralization observed among individuals and, more importantly, within one individual during different time periods and between different sites in the same mouth (for review, see ten Cate et al., 1992).

Regardless of this, some general findings can be inferred: During in situ demineralization, up to 62 vol%μm/day may be removed from enamel. For dentin specimens, this value may be as high as 89 vol%μm/day.

For remineralization, during fluoride dentifrice treatment, a median deposition rate of 0.7%/day (for lesions with integrated mineral loss values between 2000 and 4000 vol%μm) is found. The rate of deposition seems to be correlated with the extent of the pre-formedlesion. This suggests that the number of sites (crystallite surface) available for calcium phosphate precipitation is an important parameter. However, the rate at which mineral ions are supplied (by saliva) could also be a limiting factor, as is shown in a theoretical analysis of mass-balance of enamel constituents. The few studies that have monitored caries development in time reveal that mineral loss (and also lesion progression in depth) from enamel in situ is linear in time. This is in contrast to results from laboratory findings.

Get full access to this article

View all access options for this article.

References

American Dental Association (1992). Proceedings, workshop on technological advances in intra-oral model systems used to assess cariogenicity. J Dent Res 71(SpecIss):804-956.

Arends J. , Christoffersen J. (1986). The nature of early caries lesions in enamel. J Dent Res 65:2-11.

Arends J. , Dijkman T. , Christoffersen J. (1987). Average mineral loss in dental enamel during demineralization . Caries Res 21:249-254.

Arends J. , Christoffersen J. , Christoffersen MR , gaard B. , Dijkman AG , Jongebloed WL (1992). Rate and mechanism of enamel demineralization in situ. Caries Res 26:18-21.

Collins Lmc , Dawes C. (1987). The surface area of the adult human mouth and thickness of the salivary film covering the teeth and oral mucosa. J Dent Res 66:1300-1302.

Creanor SL , Strang R. , Telfer S. , MacDonald I. , Smith MJ , Stephen KW (1986). In situ appliance for the investigation of enamel de- and remineralisation. A pilot study. Caries Res 20:385-391.

Damato FA , Stirrups DR , Stephen KW , Cummings A. , Strang R. (1992). Importance of experimental time during in situ de-/remineralisation studies (abstract). Caries Res 26:214.

Dawes C. , Watanabe S. , Biglow-Lecomte P. , Dibdin GH (1989). Estimation of the velocity of the salivary film at some different locations in the mouth. J Dent Res 68:1479-1482.

De Josselin de Jong E. , ten Bosch JJ (1985). Error analysis of the microradiographic determination of mineral content in mineralised tissue slices. Phys Med Biol 30:1067-1075.

10.

Dibdin GH (1990). Effect on a cariogenic challenge of saliva/ plaque exchange via a thin salivary film studied by mathematical modelling. Caries Res 24:231-238.

11.

Dijkman AG , Schuthof J. , Arends J. (1986). In vivo remineralization of plaque-induced initial enamel lesions-a microradiographic investigation. Caries Res 20 :202-208.

12.

Driessens Fcm (1982). Mineral aspects of dentistry. Basel: S. Karger.

13.

Driessens Fcm , Theuns HM , Borggreven Jmpm , van Dijk Jwe (1986). Solubility behaviour of whole human enamel. Caries Res 20:103-110.

14.

Exterkate Ram , Damen Jjm , ten Cate JM (1993). Remineralization of lesions in single sections of bovine enamel by solutions with varying calcium-to-phosphate ratios (abstract) . Caries Res 27:217.

15.

Feagin FF , Jeansonne BG (1973). Effective fluoride concentrations to promote apatite mineralization at the enamel surface. AL J Med Sci 10:107-114.

16.

Featherstone Jdb , Zero DT ( 1992). An in situ model for simultaneous assessment of inhibition of demineralization and enhancement of remineralization. J Dent Res 71 (Spec Iss):804-810.

17.

Featherstone Jdb , Duncan JF , Cutress TW (1979). A mechanism for dental caries based on chemical processes and diffusion phenomena during in-vitro caries simulation on human tooth enamel. Arch Oral Biol 24:101-112.

18.

Gelhard Tbfm , Arends J. (1984a). In vivo remineralization of artificial subsurface lesions in human enamel. I. J Biol Buccale 12:49-57.

19.

Gelhard Tbfm , Arends J. (1984b). Microradiography of in vivo remineralized lesions in human enamel. II. J Biol Buccale 12:59-65.

20.

Hoppenbrouwers Pmm , Driessens Fcm , Borggreven Jmpm (1987). The mineral solubility of human tooth roots. Arch Oral Biol 32:319-322.

21.

Lagerlof F. , Dawes C. (1984). The volume of saliva in the mouth before and after swallowing. J Dent Res 63:618-621.

22.

Larsen MJ , Pearce Eif (1992). Some notes on the diffusion of acidic and alkaline agents into natural human caries lesions in vitro. Arch Oral Biol 37:411-416.

23.

Leach SA , Lee Gtr , Edgar WM (1989). Remineralization of artificial caries-like lesions in human enamel in situ by chewing sorbitol gum. J Dent Res 68:1064-1068.

24.

Lecomte P. , Dawes C. (1987). The influence of salivary flow rate on diffusion of potassium chloride from artificial plaque at different sites in the mouth . J Dent Res 66 :1614-1618.

25.

Lervik T. , Haugejorden O. , Aas C. (1990). Progression of posterior approximal carious lesions in Norwegian teenagers from 1982 to 1986. Acta Odontol Scand 48:223-227.

26.

Margolis HC (1990). An assessment of recent advances in the study of the chemistry and biochemistry of dental plaque fluid. J Dent Res 69:1337-1342.

27.

Mellberg JR (1991). Relationship of original mineral loss in caries-like lesions to mineral changes in situ. Caries Res 25:459-461.

28.

Mellberg JR , Castrovince LA , Rotsides ID (1986). In vivo remineralization by a monofluorophosphate dentifrice as determined with a thin-section sandwich method. J Dent Res 65:1078-1083.

29.

Mellberg JR , Petrou ID , Grote NE (1992a). Findings from an in situ thin-section sandwich model for evaluating cariogenic and anti-cariogenic activity. J Dent Res 71(Spec Iss) :850-855.

30.

Mellberg JR , Petrou ID , Grote NE (1992b). A study of ability of an in situ remineralization model to differentiate between the effects of two fluoride dentifrices that produced significantly different clinical caries results. J Dent Res 71:1169-1172.

31.

Moreno EC , Aoba T. , Gaffar A. (1989). Physical chemistry of calculus formation. In: ten Cate JM , editor. Recent advances in the study of dental calculus. Oxford: IRL Press, 129-142.

32.

Nyvad B. , ten Cate JM , Fejerskov O. (1989). Microradiography of experimental root surface caries in man. Caries Res 23:218-224.

33.

Ögaard B. , Rolla G. , Helgeland K. (1983). Alkali soluble and alkali insoluble fluoride retention in demineralized enamel in vivo. Scand J Dent Res 91:200-204.

34.

gaard B. , Rølla G. , Arends J. (1988). In vivo progress of enamel and root surface lesions under plaque as a function of time. Caries Res 22:302-305.

35.

Robinson C. , Hallsworth AS , Shore RC , Kirkham J. (1990). Effect of surface zone deproteinisation on the access of mineral ions into subsurface carious lesions of human enamel. Caries Res 24:226-230.

36.

Schafer F. , Raven SJ , Parr TA ( 1992). The effect of lesion characteristic on remineralization and model sensitivity. J Dent Res 71(Spec Iss):811-813.

37.

Schiipbach P. , Lutz F. , Guggenheim B. (1992). Human root caries: histopathology of arrested lesions. Caries Res 26:153-164.

38.

Shellis RP (1984). Relationship between human enamel structure and the formation of caries-like lesions in vitro. Arch Oral Biol 12:975-981.

39.

Stephen KW , Damato FA , Strang R. (1992). An in situ enamel section model for assessment of enamel re/demineralization potential. J Dent Res 71(Spec Iss):856-859.

40.

Strang R. , Damato FA , Creanor SL , Stephen KW (1987). The effect of baseline lesion mineral loss on in situ remineralization. J Dent Res 66:1644-1646.

41.

ten Bosch JJ , Angmar-Mansson B. (1991). A review of quantitative methods for studies of mineral content of intra-oral incipient caries lesions. J Dent Res 70:2-14.

42.

ten Cate JM (1986). Demineralization models: mechanistic aspects of the caries process with special emphasis on the possible role of foods. J Dent Res 65(Spec Iss):1511-1515.

43.

ten Cate JM , Rempt HE (1986). Comparison of the in vivo effect of a 0 and 1,500 ppm F MFP toothpaste on fluoride uptake, acid resistance and lesion remineralization . Caries Res 20:193-201.

44.

ten Cate JM , Timmer K. , Shariati M. , Featherstone Jdb (1988). Effect of timing of fluoride treatment on enamel de- and remineralization in vitro: a pH-cycling study. Caries Res 22:20-26.

45.

ten Cate JM , Nyvad B. , van de Plassche-Simons YM , Fejerskov O. (1991). A quantitative analysis of mineral loss and shrinkage of in vitro demineralized human root surfaces. J Dent Res 70:1371-1374.

46.

ten Cate JM , van de Plassche-Simons YM , van Strijp Ajp (1992). Importance of model parameters in the assessment of intra-oral remineralization. J Dent Res 71 (Spec Iss) :879-883.

47.

Theuns HM , van Dijk Jwe , Driessens Fcm , Groeneveld A. (1983). Effect of time and degree of saturation of buffer solutions on artificial carious lesion formation in human tooth enamel. Caries Res 17:503-512.

48.

Vernon PG , Raven SJ , Gilbert RJ , Parr TA , Dundon KA (1992). The effect of study design on in situ treatment of carious enamel lesions. J Dent Res 71(Spec Iss):814-818.

49.

Vogel GL , Carey CM , Chow LC , Gregory TM , Brown WE (1988). Micro-analysis of mineral saturation within enamel during lactic acid demineralization. J Dent Res 67 :1172-1180.

50.

Weatherell JA , Robinson C. , Ralph JP , Best JS ( 1984). Migration of fluoride in the mouth. Caries Res 18:348-353.

51.

Wefel JS , Jensen ME (1992). An intra-oral single-section demineralization/remineralization model. J Dent Res 71(Spec Iss): 860-863.