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Dental erosive wear is a multifactorial condition of high prevalence. Nowadays, there is an emphasis on discovering individual genetic predisposition for the development of this condition. Aquaporins (AQPs) are water channel proteins expressed in salivary glands, as well as during tooth development. They are involved in salivary secretion and composition and linked to physiological protection of the oral cavity. The aim of this study was to explore the relationship between different dental erosive wear phenotypes, AQP genes, and selected environmental factors. Data from 705 dental patients were used to investigate the association between dental erosive wear phenotypes and AQPs’ single-nucleotide variants. Phenotypes were further analyzed considering diet and oral hygiene data, using logistic regression analysis, as implemented in PLINK, with the assumption that dental erosive wear is a complex gene-environment model. Associations were found between severe erosive tooth wear and rs2878771 (AQP2) for the genotypic (p = 0.02) and dominant (p = 0.03) models, and rs3736309 (AQP5) for the allelic model (p = 0.02). Logistic regression analyses, after implementing the Bonferroni correction, showed that several significant associations were present when covariates were included, suggesting that a strong environmental component is present. Our results show that dental erosive wear establishes under a gene-environmental complex model.

Objective: Salivary flow rate exerts an essential impact on the development and progression of dental erosion. In this work, the experimental dental erosion in non-obese diabetic (NOD) mice with reduced salivary flow rate was induced, and the erosive effect of acidic drinks on their dentition was studied. Material and methods: Three acidic drinks (sports drink, cola light drink and sugar containing cola drink) were given to adult NOD mice (groups: N = 11) as the only drink for 6 weeks. Two control groups were included; wild type and NOD control (groups: N = 9). Experimental and control (water) teeth were dissected out and observed by scanning electron microscopy (SEM). Mandibular first molars were subsequently embedded in Epon, ground transversely, observed again by SEM, and the enamel thickness and tooth height were measured. Results: Mandibular molars were considerably more eroded than maxillary molars. The erosive process started at the top of the cusps and subsequently extended in the cervical, mesio-distal, and pulpal direction. Erosive lesions were evident in increased succession from sports drink, cola light to cola drink exposed mandibular molars, with the lingual tooth height being approximately 23%, 26%, and 37% lower, respectively, compared to the control. The lingual enamel was approximately 48% thinner in sports drink molars and 62% thinner in cola light molars. In cola drink molars, the lingual enamel was totally eroded, and significant erosion of dentine was evident. Conclusion: Reduced salivary flow, together with a high consumption of acidic drinks, results in severe erosion of NOD mice molars.

Aim: To describe the distribution of enamel-, dentin-, root- and secondary caries within an elderly population in Northern-Norway.Material and methods: A study population (n = 1 173) was divided in...

Background: There is a need for analytical techniques for measuring Erosive Tooth Wear (ETW) on natural surfaces in clinical studies. The purpose was to investigate the use of two instruments aimed to assess initial to more advanced stages of ETW. Methods: Human premolar enamel samples (2x3mm) (n = 24), were polished flat and mounted in resin cylinders (4 cylinders, 6 samples in each). Part 1: Baseline analyses by White Light Interferometer (WLI), Surface Reflection Intensity (SRI: TableTop and OptiPen) and Surface Hardness (SH). Erosion (1% citric acid (pH 3.6) for 1, 2, 4, 6, 8, 10 min. SRI and SH analyses after every erosion episode and by WLI after 10 min. New indentations were made and enamel loss; was measured by change in indentation depths from toothbrush abrasion (200 g, 60 strokes, 30 s). Another series of 2 × 5 min erosion (totally15 min and 20 min) was analysed with SH and SRI after each erosion, and by WLI (on samples and impressions of samples) after 20 min. Part 2 investigated WLI performance in the interface where initial erosion increases in severity and substance loss occurs. The samples were repolished. Baseline analyses by WLI, SRI (TableTop and OptiPen) and SH. Four cylinders were etched for 1, 2, 4, 8 min respectively and analysed by SRI, SH on samples, and WLI on samples and impressions). Results: Part1: SRI decreased from baseline to ~ 6 min etch and increased slightly after abrasion, the two devices correlated well (ICC 0.98 p < 0.001, Spearmans rs 0.91 p < 0.001). SH decreased nearly linearly to 10min etch, but increased distinctly after abrasion. Mean enamel loss from abrasion alone was 0.2 μm (change in indentation depths). After 10 min etch, it was 0.27 μm (WLI) and after 20 min etch, it was 2.2 μm measured on samples vs 2.4 μm on impressions of samples (7% higher). Part 2: From baseline to 8 min etch; SRI and SH decreased whereas WLI presented increasing etch depths. Conclusions: With some adjustments, the use of SRI and WLI in combination seems to be a promising strategy for monitoring ETW in clinical studies. Keywords: Erosive tooth wear, Clinical studies, Measurements

Studies of wine tasters and patients with self-induced vomiting have revealed that 30-50% of individuals at high risk do not develop erosive lesions. The aim was to investigate this apparent individual susceptibility to enamel erosion. Two enamel specimens were made from each of 3 premolars from 8 persons (donors). Six acrylic mouth appliances were worn by 6 volunteers (carriers). One specimen from each donor was mounted on each appliance. The carriers wore the appliances for 9 days. The appliances were immersed in 0.01 M HCl for 3 min twice per day to imitate a vomiting/reflux situation. The enamel specimens were analysed by a white-light interferometer to measure enamel loss (in micrometres). The enamel loss varied significantly both between the donor teeth (p = 0.009) and the carriers (p = 0.004). The lesion in the specimen with the largest amount of enamel loss was 4 times as deep as in the specimen with the lowest. In 1 carrier, all specimens displayed enamel loss above the mean, including the specimen from the donor with the most resistant enamel. The variation in susceptibility to erosion among individuals appears to be influenced both by the sustainability of the enamel and by factors in the oral environment. This could explain the variation in prevalence and severity of dental erosions among patients exposed to similar acidic challenges. The results suggest that for certain individuals, only minimal acidic challenges may be sufficient to cause damage to the teeth, while others may never develop dental erosions despite extensive exposure to acid.

Objective Consumption of acidic food and drinks is considered as important risk factor for development of dental erosion. There are several in vitro and in situ studies focusing on the risk indicators and preventive treatment, however, the need for a standardized animal model has been emphasised for many years. The aim was to establish an animal model of extrinsic dental erosion, which may serve as a standard for future studies to improve our understanding of the erosion. Design Two acidic drinks, sports drink and cola drink, were given to young mice for six weeks. Experimental and control (water) molars and incisors were dissected out and observed by scanning electron microscopy (SEM). Mandibular first molars were subsequently ground transversely and observed again by SEM. The tooth height and enamel thickness were measured on the SEM images. Results The lingual surface of the mandibular molars was most eroded after consumption of acidic drinks. The cola drink exhibited higher erosive effect on mandibular molars compared to sports drink. The lingual tooth height, compared to control, was about 34% and 18% lower in the cola drink and sports drink molars, respectively. Compared to the control molars, the lingual enamel was about 23% thinner in the sports drink molars and totally eroded on the certain lingual areas of the cola drink molars. Conclusions This new animal model of extrinsic dental erosion and the presented method with ground molars observed in SEM are suitable for further studies, which will gain deeper insights into the erosive disease.

Not all individuals at risk for dental erosion (DE) display erosive lesions. The prevalence of DE is higher among male subjects. The occurrence of DE may depend on more than just acidic challenge, with genetics possibly playing a role. The aim of this study was to investigate the association of enamel-formation genes with DE. One premolar and a saliva sample were collected from 90 individuals. Prepared teeth were immersed in 0.01 M HCl (pH 2.2), and enamel loss (μm) was measured using white light interferometry. DNA was extracted from saliva, and 15 single-nucleotide polymorphisms were analysed. Allele and genotype frequencies were related to the enamel loss of the specimens. Single-marker and haplotype analyses were performed using sex as a covariate. Mean enamel loss was higher for male donors than for female donors (P = 0.047). Significant associations were found between enamel loss and amelogenin, X-linked (AMELX), tuftelin 1 (TUFT1), and tuftelin-interacting protein 11 (TFIP11). Analyses showed significant associations between variation in enamel-formation genes and a lower susceptibility to DE in female subjects. The results indicate that susceptibility to DE is influenced by genetic variation, and may, in part, explain why some individuals are more susceptible than others to DE, including differences between female subjects and male subjects.

Aim: To evaluate how concentration and pH of TiF4 influence the erosion-protective effect. Methods: Specimens were treated with a TiF4 solution: (1) 0.5 M F, pH 1.2, (2) 0.05 M F, pH 2.1, (3) 0.5 M F, pH 2.1, or (4) 0.05 M F, pH 1.2; then, they were exposed to HCl. Results: After 2 min, the proportions of the area covered with the coating were 93, 71, 17 and 0% in groups 1–4. When present, the coating seemed to protect the surface. After 6 min, a coating could only be seen in group 1 (43%). Conclusion: Reducing the concentration of TiF4 and increasing the pH of the solution decreased the protective effect.

This was to determine the prevalence, distribution of affected teeth and severity of MIH in adolescents from Northern Norway. It was part of a cross-sectional health survey Fit Futures including 16-year-olds from two neighbouring municipalities, Tromso and Balsfjord. The prevalence of MIH was 13.9 % (110 of 794). The maxillary first permanent molars (FPMs) were 1.6 times more frequently affected than in the mandible (P

This chapter presents a newly developed dental erosive wear risk assessment tool designed for use by general dental practitioners, dental educators, and dental students. The tool guides the user through the most common risk factors associated with dental erosive wear, and when combined with the Basic Erosive Wear Examination (BEWE) or other similar scoring system, leads to a final decision on patient risk status. An initial screening section helps the dentist to decide whether it is necessary to perform a more comprehensive dental erosive wear risk assessment. When there is clearly a need for further assessment, all dental erosive wear lesions are then recorded using the index of choice, and the dentist decides how the recorded conditions will be documented. The dentist then uses the Dental erosive wear risk assessment (DEWRA) form, where dietary and oral hygiene habits, general health status, and clinical conditions are evaluated using a thorough patient interview. An overall patient risk category is chosen and the section for treatment planning and advice to the patient can then be used. The last part of this chapter provides a brief explanation of the various risk factors that are included in the DEWRA form.

High and low concentration NaF regimes have shown caries protective properties, but the preventive effect against erosive/abrasive wear is unclear. AIM. To measure the inhibiting effect on enamel wear of low and highly concentrated sodium fluoride (NaF) toothpastes and a stannous (SnF2) fluoride gel in a single-blind, randomized in situ study, using a White Light Interferometer.Sixteen human molars were each divided into four specimens, mounted on acrylic mouth appliances and worn by eight volunteers for 9 days. Experimental procedures were performed in the laboratory. The enamel specimens were brushed every day with fluoride-free toothpaste. Treatments; group 1: no fluoride treatment (control), group 2: SnF2 gel 2500 ppm F (5 min) every third day, group 3: NaF toothpaste 5000 ppm F 5 min every third day and 2 min the other days, group 4: NaF toothpaste 1450 ppm F (2 min) every day. In order to mimic gastric reflux/vomiting, the specimens were etched with 0.01 M HCl for 2 min twice a day.The mean step height (µm) for the control specimens was -32.9 (SD = 6.8). The mean values for the other groups were -22.2 (SD = 8.4) (group 2), -30.8 (SD = 7.8) (group 3) and -31.4 (SD = 7.7) (group 4). Compared with the control, the SnF2 treated specimens showed significantly lower wear. The NaF toothpastes gave no significant protective effect.Application of SnF2 gel every third day gave protection against erosive-abrasive challenges. Daily application of both low concentration and high concentration NaF toothpaste provided no protection.

To compare single-application fluoride formulations on enamel erosion and erosion-abrasion in vitro.Enamel specimens were pretreated with either sodium, tin, titanium, or sodium/calcium fluoride and subjected to either an erosion model or an erosion-abrasion model, after which optical profilometry was used to measure enamel step height loss.For erosion, the titanium fluoride (P.001) reduced enamel loss, whereas the calcium, tin, and sodium treatments showed no significant effects (P.05). For erosion-abrasion, the titanium fluoride increased enamel loss in comparison to control (P.001).Titanium fluoride has differing effects on enamel loss from erosion and erosion-abrasion models.

Stannous fluoride solutions have shown promising protective effect against erosion/abrasion, but the effect of SnF2 toothpastes is uncertain. The aim of the study was to test the inhibiting effect of two SnF2 toothpastes and a SnF2 solution against erosive/abrasive wear in a single-blind, randomised in situ study, using a white light interferometer. Sixteen human molars were each divided into four specimens, mounted on mouth appliances and worn by 8 volunteers for 9 days. Specimens were brushed with toothpaste twice each day for 30 s either with fluoride-free toothpaste or toothpastes including SnF2. Toothpaste was left on the surface for 90 additional seconds. Group 1, fluoride-free toothpaste; Group 2, toothpaste A (0.4 % SnF2, Solidox); Group 3, toothpaste B (0.454 % SnF2, Oral-B®); Group 4, brushed with fluoride-free toothpaste (30 s) and treated for 2 min with a 0.4 % SnF2 solution (1,000 ppm F). To mimic gastric reflux/vomit, specimens were etched for 2 min twice a day (0.01 M HCl). Procedures were performed extra-orally. The mean enamel wear (in μm) for the control specimens was: −29.2 ± SD 10.5; for group 2 −14.5 SD ± 9.3; for group 3 −33.3 SD ± 7.4, and for group 4 +0.4 SD ± 1.3. The specimens treated with SnF2 solution and toothpaste A showed significantly lower enamel wear than the control group. Toothpaste B gave no significant reduction in enamel wear. The SnF2 solution fully protected the enamel surface against erosive and abrasive challenges. The SnF2 toothpaste A (Solidox) showed less, but significant protection of the enamel, while no statistically significant protection was demonstrated by SnF2 toothpaste B (Oral-B® Pro-Expert).

Clinical photographs and study models may provide permanent records of dental erosion and be useful supplements to clinical registration. To assess the reliability and validity of registrations on clinical photographs and study models performed by a group of examiners. Thirty tooth surfaces were selected and assessed clinically, using the visual erosion dental examination system. The chosen surfaces provided the whole range of dental erosions including sound surfaces. The tooth surfaces were photographed and impressions were obtained for preparation of study models. Thirty-three dentists examined and scored the selected surfaces both on photographs and study models. The quality of diagnosis (AUC, area under curve) was slightly higher using photographs as compared to study models. The difference was statistically significant when the validation criterion was erosion, assuming dentine exposure. The inter-method agreement on photographs and study models versus the clinical evaluation were approximately in the same range with a mean κw of 0.48 and 0.43, respectively. When comparing study models with photographs the mean κw was 0.52. The intra-examiner agreement was strong/substantial for both (photographs mean κw = 0.63 and study models mean κw = 0.60). Linear weighted Cohen’s kappa (κw) was used to evaluate inter-method and intra-examiner agreement. Receiver operating characteristic and area under the curves were used to express diagnostic quality according to a clinical examination. The results indicated that photographs were as good as study models for recording erosive lesions.

It is not known whether application of fluoride agents on enamel results in lasting resistance to erosive/abrasive wear. We investigated if one daily mouth rinse with sodium fluoride (NaF), stannous fluoride (SnF2) or titanium tetrafluoride (TiF4) solutions protected enamel against erosive/abrasive wear in situ (a paired, randomised and blind study). Sixteen molars were cut into 4 specimens, each with one amalgam filling (measurement reference surface). Two teeth (2 × 4 specimens) were mounted bilaterally (buccal aspects) on acrylic mandibular appliances and worn for 9 days by 8 volunteers. Every morning, the specimens were brushed manually with water (30 s) extra-orally. Then fluoride solutions (0.4% SnF2 pH 2.5; 0.15% TiF4 pH 2.1; 0.2% NaF pH 6.5, all 0.05 m F) were applied (2 min). Three of the specimens from each tooth got different treatment, and the fourth served as control. At midday, the specimens were etched for 2 min in 300 ml fresh 0.01 m hydrochloric acid and rinsed in tap water. This etch procedure was repeated in the afternoon. Topographic measurements were performed by a white-light interferometer. Mean surface loss (±SD) for 16 teeth after 9 days was: SnF2 1.8 ± 1.9 µm, TiF4 3.1 ± 4.8 µm, NaF 26.3 ± 4.7 µm, control 32.3 ± 4.4 µm. Daily rinse with SnF2, TiF4 and NaF resulted in 94, 90 and 18% reduction in enamel erosive/abrasive wear, respectively, compared with control (p < 0.05). The superior protective effect of daily rinse with either stannous or titanium tetrafluoride solutions on erosive/abrasive enamel wear is promising.