ArticlePDF Available

Exposure Time of Enamel and Dentine to Saliva for Protection against Erosion: A Study in vitro

Authors:

Abstract and Figures

Previous research, mainly on enamel, supports a protective role for salivary pellicle against erosion. Pretreatments have tended to be lengthy (24 h or more) and of questionable relevance to the regular intake of acidic food and drink by many individuals. The aim of this study in vitro was to determine the protective effect of salivary pellicle formed on enamel and dentine over time periods up to 4 h. Flattened, polished human enamel and dentine specimens were pretreated with unstimulated human saliva from a single donor for 2 min, 30 min (enamel only), 1, 2, or 4 h. Controls were exposed to water for the same times. Specimens were then exposed to 0.3% citric acid, pH 3.2 for 10 min with stirring. This cycle was carried out 12 times. Tissue loss was measured by profilometry after 3, 6, 9 and 12 cycles. For enamel, statistically significant protection was found at >or=1 h. For dentine, significant protection was achieved at 2 min. Salivary pellicle offered proportionately greater protection to enamel than dentine. Cautiously extrapolating these in vitro data suggests that pellicle should offer erosion protection to individuals who imbibe acidic drinks at frequencies of 1 h or less.
Content may be subject to copyright.
Fax +41 61 306 12 34
E-Mail karger@karger.ch
www.karger.com
Original Paper
Caries Res 2006;40:213–217
DOI: 10.1159/000092228
Exposure Time of Enamel and Dentine to
Saliva for Protection against Erosion:
A Study in vitro
S. Wetton J. Hughes N. West M. Addy
Division of Restorative Dentistry, University of Bristol, Dental School, Bristol , UK
vitro data suggests that pellicle should offer erosion pro-
tection to individuals who imbibe acidic drinks at fre-
quencies of 1 h or less.
Copyright © 2006 S. Karger AG, Basel
Tooth wear, as a potential threat to the longevity of the
human deciduous and permanent dentitions, has attract-
ed increasing research interest in recent years [for reviews
see Mair, 2000; Bartlett and Smith, 2000; Addy and
Hunter, 2003]. Of the processes involved in tooth wear,
arguably erosion or, perhaps more correctly, chemico-
physical wear, has been most studied [for reviews see Im-
feld, 1996; Nunn, 1996, 2000; Zero and Lussi, 2000]. A
number of acidic substances, from intrinsic and extrinsic
sources, have been implicated in dental erosion [Zero and
Lussi, 2000]. Notable amongst these aetiological factors
have been soft drinks, which is perhaps not surprising
given their increasing intake over recent decades by de-
veloped nations [British Soft Drinks Association, 1991;
O’Brien, 1993, Dugmore and Rock, 2004]. As with other
diseases and conditions, which affect the teeth, erosion
appears to show considerable individual and site-specifi c
variation [Hall et al., 1999; Nunn, 2000]. A whole host of
factors, contributing to this variation, have been suggest-
Key Words
Enamel Dentine Tooth wear Dental erosion
Saliva Salivary pellicle
Abstract
Previous research, mainly on enamel, supports a protec-
tive role for salivary pellicle against erosion. Pretreat-
ments have tended to be lengthy (24 h or more) and of
questionable relevance to the regular intake of acidic
food and drink by many individuals. The aim of this study
in vitro was to determine the protective effect of salivary
pellicle formed on enamel and dentine over time periods
up to 4 h. Flattened, polished human enamel and dentine
specimens were pretreated with unstimulated human
saliva from a single donor for 2 min, 30 min (enamel
only), 1, 2, or 4 h. Controls were exposed to water for the
same times. Specimens were then exposed to 0.3% citric
acid, pH 3.2 for 10 min with stirring. This cycle was car-
ried out 12 times. Tissue loss was measured by profi lom-
etry after 3, 6, 9 and 12 cycles. For enamel, statistically
signifi cant protection was found at 6 1 h. For dentine,
signifi cant protection was achieved at 2 min. Salivary
pellicle offered proportionately greater protection to
enamel than dentine. Cautiously extrapolating these in
Received: November 16, 2004
Accepted after revision: July 19, 2005
Martin Addy
Division of Restorative Dentistry, Dental School
Lower Maudlin Street
Bristol BS1 2LY (UK)
Tel. +44 1179 284 506, Fax +44 1179 284 100, E- Mail Martin.Addy@bristol.ac.uk
© 2006 S. Karger AG, Basel
0008–6568/06/0403–0213$23.50/0
Accessible online at:
www.karger.com/cre
Wetton/Hughes/West/Addy
Caries Res 2006;40:213–217
214
ed. One such factor, which has featured in debates on
variability of erosion, is the salivary pellicle [Sonju Clasen
et al., 2000]. There is much evidence that salivary pellicle
inhibits demineralisation of enamel and dentine, drawn
from studies in situ and in vitro [Moreno and Zahradnik,
1979; Meurman and Frank, 1991; Hannig, 1998, 1999;
Amaechi et al., 1999; Hall et al., 1999; Hannig and Balz,
1999, 2001; Sonju Clasen et al., 2000; Young et al., 2000].
The protection could be physical, chemical or both.
A majority of studies reporting that pellicle is protec-
tive against erosion have been concerned with enamel,
usually bovine, although some studies have used human
enamel. These studies also used pellicle formation times
of many hours, often 24 h, or many days [Hall et al., 1999;
Hannig and Balz, 1999, 2001; Hara et al., 2003]. How-
ever, one study [Hannig et al., 2003] failed to show ad-
ditional protection beyond 2 h of pellicle formation, even
though pellicle thickness and amino acid composition are
known to increase as a function of time [Lie, 1977; Skjör-
land et al., 1995; Sonju Clasen et al., 1997; Hannig, 1999].
Since acid exposure thins or even removes pellicle rela-
tively quickly [Hannig and Balz, 2001; Hannig et al.,
2003], lengthy formation times are not relevant to per-
sons most at risk from erosion, namely individuals who
imbibe acid fl uids frequently throughout the day. The
aim of the present study in vitro was to determine the
shortest time of exposure to saliva, which would result in
a reduction in erosion of enamel and dentine compared
to water-pretreated controls. The null hypothesis was that
erosion protection afforded by saliva to enamel and den-
tine would not be infl uenced by the time of exposure to
saliva, between 2 min and 4 h.
Materials and Methods
Preparation of Specimens
The detailed methods for the preparation of the enamel and
dentine specimens have been described previously [West et al.,
1998]. Pieces of enamel and dentine were cut from human third
molars, which had been extracted from individuals aged 18–35
years. The dentine pieces were placed into moulds measuring 30 !
30 ! 5 mm with the root surface downwards. Enamel pieces were
placed into moulds measuring 8 ! 6 ! 2 mm with the outer enam-
el surface downwards. The moulds were then fi lled with epoxy res-
in, which was allowed to set for at least 24 h. Specimens were then
removed from the moulds and polished using 1,200 grit abrasive
discs in a lapping and polishing machine, with water lubrication,
to expose a window of enamel or dentine with an acceptance profi le
of 8 0.3
m, measured by contact profi lometry. The profi lometer
(Surfometer, Planar Products Ltd., Sunbury on Thames, UK) had
a diamond stylus with a tip radius of 20
m and a head velocity of
10 mm min
–1
. The force of the stylus varied linearly with defl ection
at a rate of 8 mg
m
–1
up to a maximum of 1 g at 100
m. Speci-
mens were then taped with parallel strips of PVC tape to leave a
window of enamel or dentine 2 mm wide. Groups of six specimens
were allocated to each treatment.
Treatments
Unstimulated saliva was obtained from the same 28-year-old
male (S.W.) throughout the day on experimental days by allowing
saliva to dribble into screw cap 30-ml polystyrene universal con-
tainers at room temperature. Collection was always at least 1 h af-
ter any intake of food or drink and collected saliva was used im-
mediately. Groups of specimens were soaked in 20 ml saliva or
water for 2 min, 1, 2 and 4 h, removed and rinsed in running tap
water for 30 s and then placed in 200 ml of 0.3% citric acid, ad-
justed to pH 3.2 with NaOH at 35 ° C, with constant, overhead
stirring at 270 rpm [for details see Eisenburger et al., 2000]. After
10 min, to simulate a sipped drink, specimens were removed and
washed in water as before. The cycle of exposure to water or saliva,
then acid was repeated a total of 12 times. After 3, 6, 9 and 12 cycles
the tape was removed and tissue loss measured across two zones of
the window using the contacting profi lometer. Following measure-
ment, specimens were re-taped to expose the same window and the
cycles continued. As negative controls, two groups of enamel and
dentine were cycled through water or saliva and then soaked in
water for 10 min: a total of 12 cycles being performed. In a supple-
mentary experiment a group of enamel specimens was assessed for
erosion protection after 30 min exposure to saliva. Measurements
were only taken after the 12th cycle.
Statistical Methods
T
he sample size of 6 specimens per group was chosen to pro-
vide 80% power to demonstrate a minimum 10% difference be-
tween saliva- and water-treated groups at the 95% probability
level. Descriptive statistics (mean and standard deviation) are
given for erosion by cycles and between enamel and dentine. The
erosion of saliva-treated enamel and dentine after the 12th cycle
was compared with that in the water-treated controls by unpaired
t tests.
Results
Erosion of enamel for the saliva- and water-pretreated
specimens is shown in table 1 and for dentine in table 2 .
The control enamel and dentine specimens exposed to
water or saliva and then ‘eroded’ in water showed no mea-
surable change and specimens all remained at their base-
line measurements. For all enamel and dentine groups,
the fi rst mean increment of loss at cycle 3 was the great-
est, except enamel treated for 2 min with water. Thereaf-
ter the pattern was, in most cases, approximately linear.
At cycle 12, for water-treated groups, with the exception
of the 2-min pretreatment, the mean loss of enamel was
always greater than dentine. With saliva pretreatment,
erosion was similar in enamel and dentine at cycle 12.
Salivary Erosion Protection Caries Res 2006;40:213–217 215
For enamel, after every cycle and pre-exposure time,
with one exception (2 min saliva versus water at cycle 3),
erosion depths in samples pretreated with saliva were
lower than in water-treated controls. At cycle 12 there was
no signifi cant difference in enamel erosion between water
and saliva groups for 2-min pretreatment time, but sig-
nifi cantly less erosion depth in saliva-treated samples
than in water-treated samples at 1, 2 and 4 h. The average
percentage reduction in erosion at 1, 2 and 4 h saliva pre-
treatment was 37% (range 33–44%). In the separate 30-
min pretreatment time experiment, the erosion depth in
saliva-treated specimens was 19.5 (SD 4.05)
m, and this
was not signifi cantly different from any water controls
(p 1 0.05).
For dentine at cycle 12, erosion was always less in sa-
liva-treated samples than in water-treated samples. At
cycle 12 the differences between saliva and water pre-
treatments were signifi cantly different for all pretreat-
ment times. The actual mean protection in proportional
terms was at 1 h greater for enamel compared to dentine:
44% compared to 14%.
Discussion
The cyclical model was used to amplify the possible
protective effect of saliva and to simulate the intake of
soft drinks over a period of several days. Such a protocol
has been used in a number of studies in situ and in vitro
on the erosive potential of commercially available soft
drinks [e.g. West et al., 1998]. The method used in the
present study employed a single source of saliva. This was
Table 1. Erosion depths (
m) of enamel specimens after pretreatment for various times with saliva or water
Cycles Saliva pretreatment time
2 min 60 min 120 min 240 min
saliva water saliva water saliva water saliva water
0 0.10 (0.05) 0.11 (0.09) 0.04 (0.09) 0.10 (0.05) 0.17 (0.08) 0.08 (0.08) 0.07 (0.09) 0.12 (0.11)
3 6.14 (0.71) 4.53 (0.82) 4.60 (1.23) 6.05 (1.09) 3.49 (0.55) 5.26 (0.48) 4.18 (0.74) 5.08 (0.82)
6 9.95 (1.73) 10.12 (0.49) 7.57 (0.60) 10.35 (2.03) 6.12 (1.04) 9.41 (0.99) 7.86 (1.35) 11.47 (2.17)
9 12.48 (6.23) 15.46 (0.99) 9.64 (1.22) 15.86 (2.28) 10.08 (1.40) 13.94 (2.35) 11.03 (1.32) 16.13 (1.89)
12 18.60 (1.56) 18.99 (0.76) 12.38 (1.92) 21.92 (2.68) 11.40 (1.44) 17.18 (1.49) 13.50 (2.42) 20.1 (2.66)
p value
1
0.59 <0.001 <0.001 0.002
Values are expressed as means (SD).
1
Comparison of saliva- and water-treated enamel specimens after 12 cycles.
Table 2. Erosion depths (
m) of dentine specimens after pretreatment for various times with saliva or water
Cycles Saliva pretreatment time
2 min 60 min 120 min 240 min
saliva water saliva water saliva water saliva water
0 0.10 (0.06) 0.04 (0.11) 0.05 (0.10) 0.04 (0.07) 0.06 (0.07) 0.08 (0.12) 0.06 (0.15) 0.07 (0.15)
3 8.58 (0.76) 7.17 (1.03) 5.28 (0.72) 7.26 (1.17) 6.12 (0.56) 7.03 (0.75) 5.48 (0.82) 6.17 (0.49)
6 11.76 (1.49) 11.24 (1.27) 9.23 (1.08) 10.69 (1.73) 9.55 (0.50) 10.72 (1.73) 8.94 (1.48) 10.69 (1.12)
9 15.32 (0.82) 16.28 (1.96) 11.68 (0.35) 12.67 (1.94) 11.67 (1.02) 14.40 (1.98) 10.70 (1.46) 14.38 (1.66)
12 17.56 (0.91) 20.97 (3.45) 13.59 (0.75) 15.77 (2.17) 12.73 (1.03) 15.55 (1.97) 12.48 (1.58) 16.60 (1.92)
p value
1
0.049 0.042 0.011 0.002
Values are expressed as means (SD).
1
Comparison of saliva- and water-treated dentine specimens after 12 cycles.
Wetton/Hughes/West/Addy
Caries Res 2006;40:213–217
216
considered essential as the variable under study was sa-
liva exposure time and therefore the saliva needed to be
as standardised as possible. Pooled saliva could have im-
proved the logistics of the study in respect of available
volumes of saliva, but accurate and reproducible pooling
from different individuals would be diffi cult to standard-
ize with any degree of certainty.
Studies in situ have clearly shown that individuals
vary in the amount of erosion experienced with the same
acid exposure [e.g. Hall et al., 1999]. One factor to explain
this may be individual variation in saliva and pellicle for-
mation. Relevant to this may be the observation that a
saliva chlorhexidine tea staining model in vitro revealed
different degrees of staining dependent on the individual
providing the saliva [Sheen et al., 2001]. It would be of
interest now to determine whether erosion was infl uenced
by different individuals’ saliva in the model. Some evi-
dence that this is a variable can be derived from published
studies in vitro and in situ with ex vivo challenge [Hall et
al., 1999]. Further in respect of the model, the acid chal-
lenge was in a stirred environment. The intake of soft
drinks produces a fl ow of liquid over the tooth surface the
rate of which infl uences the erosion process [Eisenburger
and Addy, 2003] and therefore in a study of this type is
a variable, which must also be standardized.
The data from the present study on enamel are consis-
tent with a previous investigation [Hannig et al., 2003] in
that 1-hour pretreatment of specimens with saliva afford-
ed the maximum protection with no further reduction in
erosion after longer pretreatments. The shorter pretreat-
ment times, 2 and 30 min, did not provide protection
against erosion. Certainly, pellicle does form on enamel
after very short exposure times to saliva, but the layer is
thin [Hannig, 1999]. Hannig [1999] also noted that pel-
licle thickness was a function of time with initial layers
(2 h) electron dense but the later formed layers appeared
more loosely arranged. Hannig [1999] suggested that such
outer layers could be more susceptible to shear forces.
Based on further work from this group [Hannig et al.,
2003] these outer layers appeared to afford little addi-
tional protection against erosion over the fi rst formed pel-
licle layer. The thickness of pellicle appeared to be not
only a function of time but was infl uenced by the position
in the mouth (tooth and tooth surface), which may be rel-
evant to proximity of the salivary glands’ duct openings
or frictional effects of oral mucosae, particularly the
tongue [Hannig, 1999; Amaechi et al., 1999; Hannig and
Balz, 2001]. Indeed, it has been suggested that the predi-
lection of palatal aspects of upper incisors for erosion was
due to the thinning effect of the tongue on pellicle [Mi-
losevic and Dawson, 1996; Amaechi et al., 1999]. Alter-
natively, the tongue might remove acid-softened enamel
as demonstrated in a recent study [Gregg et al., 2004].
The present study supports the idea that an optimum
pellicle thickness must be achieved to afford protection
against an acid challenge such as the ingestion of a soft
drink. The data, if consistent with what would occur in
vivo, are therefore encouraging and suggest that, except
at the extremes of acid intake, frequency and duration,
the maximum pellicle protection is likely to be achieved
or re-achieved between acid challenges that are an hour
or more apart.
The same conclusion can be drawn for pellicle protec-
tion of dentine from erosion, an area, which has received
little attention [Hall et al., 1999]. Some protection was
achieved with only 2-min saliva pretreatment, but maxi-
mum protection appeared to occur with 1-hour pretreat-
ment. At present the reason for the difference in the de-
gree of protection by saliva between enamel and dentine
can only be a matter of conjecture. One possibility is that
the saliva penetrates the tubule system to produce not
only a pellicle layer on the dentine surface and possibly
within the dentine but a meniscus of viscous liquid at the
tubule orifi ces. Although the differences within time pe-
riods were signifi cant between saliva and no saliva pre-
treatment of dentine, the proportionate saliva protection
increased from approximately 15% at 2 min and 1 h to
18 and 25% at 2 and 4 h, respectively.
Data from in vitro studies must be extrapolated with
caution to effects in vivo. The present investigation, how-
ever, is in agreement with others in vitro and in situ that
salivary pellicle or saliva pretreatment does protect den-
tine and proportionately more enamel from acid erosion.
In conclusion, this study, which attempted to titrate ex-
posure time with saliva to erosion protection for both hu-
man enamel and dentine, indicated optimum effects for
enamel at 1 h and probably less than 1 h for dentine.
Salivary Erosion Protection Caries Res 2006;40:213–217 217
References
Addy M, Hunter ML: Can tooth brushing damage
your health? Effects on oral and dental tissues.
Int Dent J 2003; 53: 177–186.
Amaechi BT, Higham SM, Edgar WM, Milosevic
A: Thickness of acquired pellicle as a determi-
nant of sites of dental erosion. J Dent Res 1999;
78: 1821–1828.
Bartlett D, Smith BGN: Defi nition, classifi cation,
and clinical assessment of attrition, erosion
and abrasion of enamel and dentine; in Addy
M, Embery G, Edgar WM, Orchardson R (eds):
Tooth Wear and Sensitivity. London, Martin
Dunitz, 2000, pp 87–92.
British Soft Drinks Association: Report of seminar
in Heidelberg 1991; factsheet No 9-7: 91.
Dugmore CR, Rock WP: A multifactorial analysis
of factors associated with dental erosion. Br
Dent J 2004; 196: 283–286.
Eisenburger M, Addy M: Infl uence of liquid tem-
perature and fl ow rate on erosion and enamel
demineralisation. J Oral Rehab 2003; 30:
1076–1080.
Eisenburger M, Hughes J, West NX, Jandt K,
Addy M: Ultrasonication as a method to study
enamel demineralisation during acid erosion.
Caries Res 2000; 34: 289–294.
Gregg T, Mace S, West NX, Addy M: A study in
vitro of the abrasive effect of the tongue on
enamel and dentine softened by acid erosion.
Caries Res 2004; 38: 557–560.
Hall AF, Buchanan CA, Millett DT, Creanor SL,
Strang R, Foye RH: The effect of saliva on
enamel and dentine erosion. J Dent 1999; 27:
333–339.
Hannig M: Die Protektive Wirkung der Pellikel
bei der Schmelzerosion durch verschiedene
Säuren. ZWR 1998; 107: 421–426.
Hannig M: Ultrastructural investigation of pellicle
morphogenesis at two different intraoral sites
during a 24-h period. Clin Oral Invest 1999; 3:
88–95.
Hannig M, Balz M: Infl uence of in vivo formed
pellicle on enamel erosion. Caries Res 1999; 33:
372–379.
Hannig M, Balz M: Protective properties of sali-
vary pellicles from two different intraoral sites
on enamel erosion. Caries Res 2001; 35: 142–
148.
Hannig M, Hess NJ, Hoth H, De V: Infl uence of
salivary pellicle formation time on enamel de-
mineralisation – an in situ pilot study. Clin
Oral Invest 2003; 7: 158–161.
Hara AT, Pedroso Turssi C, Teixeira ECN, Serra
MC, Cury JA: Abrasive wear on eroded den-
tine after different periods of exposure to sali-
va. J Oral Sci 2003; 111: 423–427.
Imfeld T: Dental erosion. Defi nition, classifi cation
and links. Eur J Oral Sci 1996; 104: 151–155.
Mair LH: Wear in the mouth: the tribological di-
mension; in Addy M, Embery G, Edgar WM,
Orchardson R (eds): Tooth Wear and Sensitiv-
ity. London, Martin Dunitz, 2000, pp 181–
188.
Meurman JH, Frank RM: Scanning electron mi-
croscopic study of the effect of salivary pellicle
on enamel erosion. Caries Res 1991; 25: 1–6.
Milosevic A, Dawson LJ: Salivary factors in vomit-
ing bulimics with and without pathological
tooth wear. Caries Res 1996; 30: 361–366.
Moreno EC, Zahradnik RT: Demineralization and
remineralization of dental enamel. J Dent Res
1979; 58: 896–902.
Nunn JH: Prevalence of dental erosion and the im-
plications for oral health. Eur J Oral Sci 1996;
104: 156–161.
Nunn JH: Prevalence and distribution of tooth
wear; in Addy M, Embery G, Edgar WM, Or-
chardson R (eds): Tooth Wear and Sensitivity.
London, Martin Dunitz, 2000, pp 93–104.
O’Brien T: Children’s Dental Health in the United
Kingdom 1993. Offi ce of Population Censuses
and Surveys. London, HMSO, 1994.
Sheen S, Banfi eld N, Addy M: The propensity of
individual saliva to cause extrinsic staining in
vitro – a developmental method. J Dent 2001;
29: 99–102.
Skjörland KK, Rykke M, Sonju T: Rate of pellicle
formation in vivo. Acta Odontol Scand 1995;
53: 358–362.
Sonju Clasen AB, Hannig M, Skjörland K, Sonju
T: Analytical and ultrastructural studies of pel-
licle on primary teeth. Acta Odontol Scand
1997; 55: 339–343.
Sonju Clasen AB, Hannig M, Sonju T: Variations
in pellicle thickness: a factor in tooth wear? in
Addy M, Embery G, Edgar WM, Orchardson
R (eds): Tooth Wear and Sensitivity. London,
Martin Dunitz, 2000, pp 189–196.
West NX, Maxwell A, Hughes JA, Parker DM,
Newcombe RG, Addy M: A method to mea-
sure clinical erosion: the effect of orange juice
consumption on erosion of enamel. J Dent
1998; 26: 329–336.
Young AR, Rykke M, Rølla G: On the nature of
the acquired enamel pellicle; in Addy M, Em-
bery G, Edgar WM, Orchardson R (eds): Tooth
Wear and Sensitivity. London, Martin Dunitz,
2000, pp 29–38.
Zero DT, Lussi A: Etiology of enamel erosion: in-
trinsic and extrinsic factors; in Addy M, Em-
bery G, Edgar WM, Orchardson R (eds): Tooth
Wear and Sensitivity. London, Martin Dunitz,
2000, pp 121–140.
... Other studies conducted by Mutahar et al. in 2017, andWetton in 2006, showed that salivary film offers protection against demineralisation [42,43]. ...
... Other studies conducted by Mutahar et al. in 2017, andWetton in 2006, showed that salivary film offers protection against demineralisation [42,43]. ...
... The results showed a decrease of around 30% of Ca concentrations in enamel, but the Ca loss was significantly reduced when saliva was used in acidic beverages. Ca loss in an acidic environment is due to the formation of complex compounds between Ca ions and citric acid, which increases dental minerals' dissolution [43]. Some studies demonstrated that citric acid could produce more pronounced erosions than phosphoric acid at similar levels of acidity. ...
Full-text available
Article
The aim of this study is to evaluate salivary remineralisation versus chemical remineralisation/infiltration of enamel, using different dentistry materials. The enamel changes were studied using confocal laser scanning microscopy (CLSM), and the depth of lesions and demineralisation/remineralisation/infiltration percentage were calculated. Additionally, the macro elemental composition of the teeth was performed using atomic absorption spectroscopy (AAS). Two studies were performed: (i) demineralisation of enamel in 3% citric acid and infiltration treatment with infiltration resin (Icon, DMG), remineralisation with Fluor Protector (Ivoclar Vivadent) and artificial saliva pH 8; and (ii) enamel demineralisation in saliva at pH 3 and remineralisation at salivary pH 8. The results showed that, firstly, for the remineralisation of demineralised enamel samples, Fluor Protector (Ivoclar Vivadent) was very effective for medium demineralised lesions followed by saliva remineralisation. In cases of deep demineralisation lesions where fluoride could not penetrate, low viscosity resin (Icon, DMG, Hamburg) effectively infiltrated to stop the demineralisation process. Secondly, remineralisation in salivary conditions needed supplementary study over a longer period, to analyse the habits, diet and nutrition of patients in detail. Finally, demineralisation/remineralisation processes were found to influence the macro elemental composition of enamel demineralisation, with natural saliva proving to be less aggressive in terms of decreasing Ca and Mg content.
... Die in der Vergangenheit erhobenen Studien zur Pellikelbeschaffenheit und ihrer Funktionen waren jedoch meist auf Schmelzprüfkörper bezogen ( Hara et al., 2006). Obwohl der Einfluss der Pellikel auf das Dentin klinisch von großer Bedeutung ist, besonders für Symptome wie freiliegende Zahnhälse und durch Attrition freigelegtes Dentin ( Abbas et al., 1985;Hannig et al., 2007;Wetton et al., 2006), gibt es aktuell nur sehr wenige Daten, die sich mit dem schützenden Effekt der Pellikel gegen Erosionen auf dem Dentin beschäftigen ( Hall et al., 1999;Wetton et al., 2006). ...
... Die in der Vergangenheit erhobenen Studien zur Pellikelbeschaffenheit und ihrer Funktionen waren jedoch meist auf Schmelzprüfkörper bezogen ( Hara et al., 2006). Obwohl der Einfluss der Pellikel auf das Dentin klinisch von großer Bedeutung ist, besonders für Symptome wie freiliegende Zahnhälse und durch Attrition freigelegtes Dentin ( Abbas et al., 1985;Hannig et al., 2007;Wetton et al., 2006), gibt es aktuell nur sehr wenige Daten, die sich mit dem schützenden Effekt der Pellikel gegen Erosionen auf dem Dentin beschäftigen ( Hall et al., 1999;Wetton et al., 2006). ...
... Untersuchungen verwendet und soll die Verweildauer der erosiven Reagenzien bei dem Konsum von sauren Säften oder Nahrungsmitteln widerspiegeln (Echterhoff, 2008;Hannig and Balz, 1999;Hannig et al., 2003;Nekrashevych and Stosser, 2003). Wurde die Einwirkzeit des erosiven Reagenz verlängert, musste mit vermehrten und verstärkten erosiven Effekten gerechnet werden (Meurman and Frank, 1991;Wetton et al., 2006). ...
... Human whole saliva, collected from a single healthy, 25-year-old male donor using an unstimulated drool method in the morning [14][15][16], was used to prepare saliva samples. In order to avoid the degradation of salivary proteins caused by bacteria, the donor was asked to refrain from either eating or smoking before sampling [17,18]. ...
... In this study, saliva was collected from one healthy donor. In order to avoid the influence of individual differences, a single donor was used to collect human whole saliva in many previous studies [14,16,40,41]. The morphology, penetration force, and friction coefficient of the original salivary pellicle in Figs. 1, 2, and 4 are consistent with the results of previous studies [23,42,43], suggesting that the saliva samples used in this study are representative. ...
Full-text available
Article
This study investigated the influence of two polyphenols on the structure and lubrication of the salivary pellicle, aiming to extend the understanding of astringency mechanisms. The salivary pellicle was prepared by the adsorption of human whole saliva on the enamel substrate. Low-astringency catechin and high-astringency tannic acid were used as astringents. The changes induced by the two polyphenols in the structure and lubrication of the salivary pellicle were examined using quartz crystal microbalance with dissipation (QCM-D) and nano-indentation/scratch technique. The salivary pellicle suffers from changes in structure and physical properties owing to protein dehydration and protein-polyphenol complexation when encountering polyphenolic molecules, causing increases in the roughness and contact angle but a decrease in the load-bearing capacity. Therefore, the lubrication performance of the salivary pellicle is impaired, leading to an increase and fluctuation of the friction coefficient. The intensity of astringency has a strong positive correlation with the water contact angle, surface roughness, and friction coefficient of the salivary pellicle. In summary, astringency is a tactile perception driven by the roughness and wettability of the salivary pellicle rather than oral lubrication, and increased intraoral friction is an inevitable consequence of astringency. The findings of this study will help promote and assist the objective evaluation of astringency.
... Tab. 31: Zusammensetzung der Remineralisationslösung sowie des synthetischen und humanen Speichels [91] Remineralisationslösung Säureeinfluss konnte bereits in einigen Studien gezeigt werden [95][96][97][98][99] . Zusätzlich wurde festgestellt, dass der Schutz durch die Pellikel beim Schmelz höher ist als beim Dentin [95,97,99] . ...
... Tab. 31: Zusammensetzung der Remineralisationslösung sowie des synthetischen und humanen Speichels [91] Remineralisationslösung Säureeinfluss konnte bereits in einigen Studien gezeigt werden [95][96][97][98][99] . Zusätzlich wurde festgestellt, dass der Schutz durch die Pellikel beim Schmelz höher ist als beim Dentin [95,97,99] . ...
Thesis
Bei verbrannten oder skelettierten Leichen ist Zahnhartsubstanz (Schmelz, Dentin, kariöses Material) häufig das einzige noch verwertbare Probenmaterial und eignet sich somit als alternative Matrix für postmortale chemisch-toxikologische Analysen. Zur Untersuchung der Einlagerungsmechanismen von Drogen und Arzneistoffen in die unterschiedlichen Zahnhartsubstanzen wurden in der vorliegenden Arbeit u.a. verschiedene In-vitro-Studien durchgeführt. Mit Hilfe einiger Modellsubstanzen (Amphetamine, Opioide/Opiate, Cocain und Benzoylecgonin) und der Verwendung von Rinderzahnpellets wurde eine Substanzaufnahme simuliert und die Einlagerung von Substanzen über den Speichel (pH-Cycling) sowie über die Blutversorgung der Pulpa in den Zahn dargestellt. Zudem wurden mögliche Einflussfaktoren auf die Substanzeinlagerungsraten untersucht. Die Einbeziehung des oralen Milieus erfolgte mit Hilfe verschiedener In-situ-Studien. Des Weiteren wurden 98 postmortal gewonnene Zähne von Verstorbenen, bei denen Hinweise auf eine Drogen- oder Medikamentenintoxikation vorlagen, untersucht. Die Zähne wurden in Schmelz, Kronendentin, Wurzeldentin und (falls vorhanden) kariöses Material getrennt und mittels LC-QTOF-MS sowie LC-MS/MS analysiert. Anschließend wurden die Ergebnisse der Zahnanalyse mit den Ergebnissen der toxikologischen Routineanalytik verglichen. Die Ergebnisse zeigten, dass sich die Substanzen stärker ins Dentin als in den Schmelz einlagern, aus dem Dentin aber auch schneller wieder herausgelöst werden können. Bei kariösen Läsionen war die Einlagerung aufgrund der porösen Struktur um ein Vielfaches höher. Insgesamt zeigte sich eine substanz- und konzentrationsabhängige Einlagerung. In postmortal gewonnenen Zähnen konnten generell häufiger Muttersubstanzen als Metabolite nachgewiesen werden, wohingegen bei instabilen Substanzen die Metabolite dominierten. Wurden Substanzen überwiegend im Schmelz und Kronendentin nachgewiesen, lag der Konsum bereits längere Zeit zurück. In Abhängigkeit von der Applikationsart kam eine verstärkte Einlagerung über den Speichel durch eine intensive Benetzung der Mundschleimhaut zustande. Ein Substanznachweis in höheren Konzentrationen im Wurzeldentin ergab sich aufgrund des direkten Kontakts mit dem die Pulpa durchströmenden Blut nach einem zeitnahen Konsum. Teilweise war eine Korrelation zur Blutkonzentration erkennbar. Durch die vorliegende Arbeit konnten grundlegende Erkenntnisse zur Einlagerung von Drogen und Arzneistoffen in Zahnhartsubstanzen erhalten werden. Diese tragen Wesentlich dazu bei, dass zukünftige Analysenergebnisse postmortal gewonnener Zähne in der Forensischen Toxikologie valide interpretiert werden können.
... [105,106] oder von Studienteilnehmern intraoral getragen (in-situ) [1,54]. Eine bislang noch nicht angewandte in-vivo-Methode ist die Verwendung exponierter Dentinflächen nicht extrahierter Zähne. ...
... Due to its higher organic matrix content, dentine is more susceptible to both attrition (Austin et al., 2010) and abrasion (Lippert et al., 2017), and it was this group where most of the wear was created. In vitro, the pellicle has previously been shown to produce a protective effect on dentine within 2 min of exposure compared to 60 min with enamel (Wetton et al., 2006). This could be why it was able to offer the most protection under the most aggressive wear conditions. ...
Full-text available
Article
Purpose This investigation aimed to compare the protective role of saliva against erosion and attrition challenges. Method Polished enamel and dentine samples (n=160) were prepared and randomly assigned to either the saliva or saliva-free group (n=40 enamel and n=40 dentine/group). Within each subgroup, they were allocated to four subgroups: negative control (deionized water exposure 10 min), erosion (0.3% citric acid 10 min), attrition (120 strokes of 300 g force), or combined erosion/attrition (0.3% citric acid 10 min then 120 strokes of 300 g force). Experimental cycles were repeated three times. Data analysis was performed using SPSS. Results The mean and standard deviation (SD) of step heights produced by the attrition and erosion/attrition groups in enamel in the saliva-free group were 5.6 µm (2.4) and 13.4 µm (2.8), respectively, while they were 2.4 µm (3.8) and 12.9 µm (3.5) in the saliva group, with no significant difference between the saliva and saliva-free groups. For dentine, the corresponding step heights were 25.2 µm (5.5) and 35.9 µm (7.9) for the saliva-free group, but 21.8 µm (5.3) and 27.3 µm (6.4) for the saliva group (p<0.001). Conclusion There was a trend that saliva decreased wear, but this was only statistically significant for erosion/attrition dentine wear.
... Dental erosion has a multifactorial etiology: the main factors are a poor oral hygiene or an inadequate hygienic technique, a diet rich in carbohydrates or a frequent intake of soft drinks and some factors linked to systemic diseases. All these elements can expose the dental enamel to acid attacks [25][26][27] and increased dental permeability [28,29]. ...
Full-text available
Article
The aim of this in vitro study was to evaluate the effects of a single dose application of two daily toothpastes on enamel exposed to acid attack. The research was conducted on human molars enamel fragments (n = 72). The two different toothpastes active ingredients were sodium fluoride (NaF) and stannous fluoride (SnF2). They were compared in protecting the surface of the enamel exposed to three acids: citric acid, lactic acid and hydrochloric acid. A spectrophotometer was used to measure the calcium ions and phosphate released in the solutions by the enamel specimens. Afterward, ionic concentrations were analyzed through the t-Student test, in order to estimate the significance level (p < 0.05) of the solubility differences obtained between the treatment and control groups. Finally, sample surfaces were analyzed with scanning electron microscopy and X-ray energy dispersive spectroscopy (SEM/EDX). The two analyzed toothpastes did not reveal any statistically significant variation in the release of calcium and phosphate (p > 0.05). Nevertheless, acid-resistant deposits were detected in samples treated with stannous fluoride and exposed to lactic acid, though the presence of tin ion deposits on samples treated with stannous fluoride was not shown. A single dose of a fluoride-based toothpaste before different acids attack, in simulated oral cavity conditions, did not show a significant preventive effect.
Article
The lack of wear resistance is always a challenge for clinical applications of resin-based dental composites (RBDCs). In this study, the role of the calcium release from RBDCs in the adsorption and lubrication of salivary proteins was investigated, aiming to provide useful insights concerning the development of high-performance RBDCs. Three experimental RBDCs with distinct calcium-releasing capabilities were prepared using calcium phosphate particles as inorganic fillers. Salivary protein adsorption and film-forming on RBDC surfaces were characterized by atomic force microscopy, while the mechanical properties and lubricating effect of salivary pellicle were examined using nano-indentation/scratch techniques. Results showed that calcium release from RBDCs plays a crucial role in mediating the electrostatic interaction between salivary proteins and composite surface, thereby promoting the formation of salivary pellicle with a multi-layer structure. The mechanical properties and lubricating effect of the pellicle are positively related to the level of calcium release. In sum, for RBDCs with robust calcium release, saliva provides effective lubrication to resist composite wear. Incorporating calcium compounds is a promising way to improve the wear resistance of RBDCs in the oral cavity.
Article
Objective: All soft and solid surfaces exposed to the oral cavity are covered by an acquired pellicle. While the pellicle adsorbed on enamel is well researched, only limited data are available on the dentin pellicle. The purpose of the present review is to summarize studies considering the composition, structure and properties of the dentin pellicle and compare them with the current state of research on enamel pellicle. Methods: The literature search was conducted using Medline database and Google Scholar, including checking reference lists of journal articles by handsearching. Thereby, 19 studies were included in the present review. Results and conclusion: The dentin pellicle has a similar ultrastructure to the enamel pellicle, which is up to 1 µm thick depending on pellicle formation time and localization in the oral cavity. In contrast, due to the lack of studies on the dentin pellicle regarding its composition and properties, a comparison to the enamel pellicle is difficult. So far, only one study showed anti-abrasive properties and data on anti-erosive properties were controversial. Despite becoming more and more clinically relevant due to the increasing frequency of dentin exposure, the dentin pellicle is largely unexplored. For further investigations it is not only necessary to standardize dentin specimens, but also to assess fundamental research on dentin itself, as its complex morphology and composition may have a crucial influence on pellicle formation. Furthermore, a more detailed knowledge of the dentin pellicle may also reveal target sites for modification in favor of its protective properties.
Article
Objectives to investigate how the composition of the acquired enamel pellicle (AEP) affected a laboratory model of Erosive tooth wear (ETW) on human enamel by comparing whole mouth saliva (WMS) to parotid saliva (PS). Methods 60 enamel specimens were prepared from extracted human teeth and were randomly assigned to 4 experimental groups: WMS (n = 20), PS (n = 20), artificial saliva (AS, n = 10) and deionised water (DW, n = 10). Following incubation, a subset of WMS (n = 5) and PS (n = 5) groups were used to collect the AEP before the erosive challenge. The rest of the blocks, had their AEP collected after five cycles of acid, wash and saliva and were then assessed for mean step height changes using a non-contacting profilometer (n = 10 each). AEP samples were collected from the enamel specimens by rubbing with filter papers soaked in sodium dodecyl sulfate. Total protein in AEP was quantified using BCA assay, individual protein components of AEP were separated and analysed using SDS-PAGE and western blot for [mucin5b, albumin, carbonic anhydrase VI (CA VI), statherin]. Specific antibody binding was quantified using purified protein standards of known concentration. Samples of AEP were also analysed by LC/MS/MS sequencing. Results WMS group had significantly (p < 0.0001) less acid-induced erosion (step height [4.16 (0.9) μm]) than PS group [6.41 (0.3) μm]. The amount of total protein, mucin5b and albumin were more dominant in WMS pellicles than PS (p < 0.0001) whereas CA VI and statherin were dominant in PS pellicles (p < 0.0001). Conclusion The composition of the acquired enamel pellicle influences the degree of protection from acid attack, possibly by altering the mechanism of protection. The in-vitro model used in this study was severe enough to cause tissue loss as opposed to just softening of the surface structure. AEP from WMS was more protective than that of PS, and its likely mechanisms of protection seem to be as a physical barrier rather than stabilising the crystal structure. Significance The protective salivary proteins against in in-vitro erosion models differ fromin-vivo studies. Therfore, it can be recommended that in-vitro laboratory models of ETW need to be assessed carefully to represent the clinical environment more closely.
Full-text available
Article
Objectives: This study prospectively examines the relationship of possible aetiological factors to the presence of tooth erosion in a cohort of children. Patients and methods: A random sample of 1,753 children was examined at age 12 and 1,308 of the same children were re-examined at age 14 years. The children were asked to complete questionnaires on both occasions, 1,149 subjects gave usable replies. The erosion index used was based upon the 1993 Survey of Children's Dental Health. Results were analysed using logistic regression. Results: At age 12 significant positive associations were found between erosion and decay experience (odds ratio [OR] = 1.48), drinking fruit juice (OR = 1.42) or fizzy pop (OR = 1.59-2.52, depending on amount and frequency). The presence of calculus (OR 0.48) or eating fruit other than apples or citrus fruit (OR 0.48) reduced the chances of erosion. High consumption of carbonated drinks increased the odds of erosion being present at 12 years by 252% and was a strong predictor of the amount of erosion found at age 14. Conclusions: Of the factors investigated, a history of dental caries and a high consumption of carbonated drinks were most closely related to the presence of dental erosion. The risk of erosion bore a strong relationship to the amount and frequency of carbonated drink consumption.
Article
An overview of tooth wear, i.e. of non-carious destructive processes affecting the teeth including abrasion, demastication, attrition, abfraction, resorption and erosion is presented. The nomenclature and classification of dental erosion commonly used in the dental literature are summarized. They are based on etiology (extrinsic, intrinsic, idiopathic), on clinical severity (Classes I to III), on pathogenetic activity (manifest, latent) or on localization (perimolysis). Interactions between erosion and abrasion, demastication, attrition, and abfraction as well as caries and low salivary flow rate are highlighted.
Article
Experimentation in vitro using organic acid buffers as demineralizing media shows that caries-like lesions can be obtained which are very similar in morphology and developmental stages to early lesions formed naturally under oral conditions. The use of these chemical systems and of mechanistic models advanced to explain the unique histological features of incipient caries have yielded a good understanding of the processes involved in caries formation. The study of natural and induced factors influencing the demineralization process has been greatly facilitated by the use of bacteriological systems in which demineralization is produced by direct colonization of cariogenic microorganisms on the surfaces of extracted teeth. Comparison of results obtained with these latter systems and with chemical systems has allowed us, for example, to elucidate the mechanism by which acquired salivary pellicles and fluoride topical solutions decrease the rate of enamel demineralization. The pellicle retards transport of matter across the enamel surface, whereas the fluoride topical solutions decrease the cariogenicity of the colonizing bacteria.
Article
A bovine tooth model system was used to study the effect of experimental salivary pellicle on enamel erosion. Test blocks with varnish-covered control surfaces in each specimen were immersed into an acidic cola beverage (pH 2.6) for 120 min, either with or without the pellicle which was grown for 7 days by using clarified human saliva. After immersion, the pellicle was removed from some specimens with 10% sodium hypochlorite (20 h at 20 degrees C) and ultrasonic bath (60 s) to study its effect on erosion. All specimens were then studied in the scanning electron microscope. The specimens without pellicle (positive controls) showed gross erosion with prism core dissolution in all study blocks. The specimens with pellicle showed occasionally a film-like integument covering the apparently intact test surfaces with adjacent enamel surfaces slightly eroded. The erosion, however, was not of the same magnitude as in the positive controls. After removing the pellicle, the enamel surfaces showed pitted appearance of the prism heads; the demineralization seemed to attack more the prism sheath areas. Thus, salivary pellicle was found to protect the underlining enamel from erosion in vitro.
Article
The literature on dental erosion is made up of a number of areas, some of which are reviewed here: there are anecdotal case reports, linking a small number of clinical cases with a possible etiological factor. The second area of evidence concentrates on case control studies in which there is a strong association with dental erosion, for example, patients with bulimia. The final piece of epidemiological evidence is beginning to emerge as prevalence studies, but the information from prevalence data worldwide is scanty. It is difficult to compare prevalence studies because of the different indices used in the various studies and also because of the different teeth assessed in the sample. Standardization of indices used would overcome some of these differences as would the reporting of results in a comparable way. However, identifying the true prevalence of erosion per se is fraught with difficulty because there may be more than one etiological factor operating and attrition and or abrasion may complicate the picture, especially in older populations. Case reports frequently associate evidence of erosion with excessive use of particular drinks or foodstuffs so they must be viewed with caution. There is an increasing awareness, amongst the dental profession, of the potential for this particular form of tooth wear to occur. It is important that the dental team is vigilant and instigates preventive measures before tooth tissue loss becomes clinically significant. The importance of erosion in dental health promotion should not be overlooked.
Article
The acquired enamel pellicle is thought to be the result of a selective adsorption of salivary proteins and to be involved in the protection of the enamel surfaces. The chemical composition of the 2-h acquired enamel pellicle is fairly well established. However, the rate of formation and the amino acid composition of the initially formed enamel pellicle have been little investigated. The aim of this study was therefore to examine the rate of pellicle formation and the amino acid composition of the initially formed enamel pellicle. Samples of human enamel surfaces were carried in the mouth for various periods of time (2.5 min to 10 h). Rate of pellicle formation was indicated as a function of oral exposure time and the time necessary to remove the proteinaceous film from the surfaces by argon ion sputtering. The chemical composition of the initially acquired pellicle was examined by amino acid analyses of pellicle material collected in vivo from enamel surfaces 15 min and 1 h after pumicing, respectively. The pellicle reached an initial thickness in about 2-3 min, at which level it stayed for about 30 min. The thickness of the acquired pellicle then increased to about three times the initial thickness and stayed at that level for the rest of the experimental period (10 h). Amino acid analyses of pellicle material collected after 15 min and after 1 h were different in that the amino acid profiles of the 15-min pellicle only contained traces of proline and arginine. It may be argued that the pellicle formation proceeds in two stages owing to the adsorption of protein aggregates and that the chemical compositions of the pellicles of the two stages differ.