Aquaporins' Influence on Different Dental Erosive Wear Phenotypes in Humans.

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.

The frequency of enamel and dentin caries lesions among elderly Norwegians.

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 into age groups: 65-69 (seniors), 70-74 (young elderly), 75-79 (elderly) and 80-94 (old elderly). Seven examiners registered presence, location and severity of caries lesions on x-rays and intra-oral photos. Severity of approximal, occlusal, secondary and root caries was graded (D1-2: into enamel; D3-5: into dentin, root caries), and decayed missing filled surfaces/teeth (DMFS/DMFT) were calculated. T-test, ANOVA and a Bonferroni correction were used.Results: The seniors had more primary caries (DS1-5) compared to the oldest age groups, while the old elderly had significantly more secondary caries than the other groups (p < .05). Of those ≥65 years 13.8% were affected with root caries, 21% among the oldest. About 48% of the old elderly had one or more surfaces with untreated caries lesions into dentin, while for the other groups the number was 35% (p < 0.05).Conclusion: Individuals seem to maintain good oral health up to at least 80 years of age. Those older than 80 years have more root caries needing more intensified caries-controlling measures and a higher prevalence of untreated dentin lesions often in need of operative treatment.

New animal model of extrinsic dental erosion-Erosive effect on the mouse molar teeth.

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.

May caries-preventive fluoride regimes have an effect on dental erosive wear? An in situ study.

OBJECTIVE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

The effect of single-application fluoride treatment on simulated gastric erosion and erosion-abrasion of enamel in vitro.

PURPOSE: To compare single-application fluoride formulations on enamel erosion and erosion-abrasion in vitro. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSIONS: Titanium fluoride has differing effects on enamel loss from erosion and erosion-abrasion models.

Self-induced vomiting and dental erosion--a clinical study.

BACKGROUND: In individuals suffering from eating disorders (ED) characterized by vomiting (e.g. bulimia nervosa), the gastric juice regularly reaches the oral cavity, causing a possible risk of dental erosion. This study aimed to assess the occurrence, distribution and severity of dental erosions in a group of Norwegian patients experiencing self-induced vomiting (SIV). METHODS: The individuals included in the study were all undergoing treatment at clinics for eating disorders and were referred to a university dental clinic for examinations. One calibrated clinician registered erosions using the Visual Erosion Dental Examination (VEDE) system. RESULTS: Of 72 referred patients, 66 (63 females and three males, mean age 27.7 years) were or had been experiencing SIV (mean duration 10.6 years; range: 3 - 32 years), and were therefore included in the study. Dental erosions were found in 46 individuals (69.7%), 19 had enamel lesions only, while 27 had both enamel and dentine lesions. Ten or more teeth were affected in 26.1% of those with erosions, and 9% had ≥10 teeth with dentine lesions. Of the erosions, 41.6% were found on palatal/lingual surfaces, 36.6% on occlusal surfaces and 21.8% on buccal surfaces. Dentine lesions were most often found on lower first molars, while upper central incisors showed enamel lesions most frequently. The majority of the erosive lesions (48.6%) were found in those with the longest illness period, and 71.7% of the lesions extending into dentine were also found in this group. However, despite suffering from SIV for up to 32 years, 30.3% of the individuals showed no lesions. CONCLUSIONS: Dental erosion commonly affects individuals with ED experiencing SIV, and is more often found on the palatal/lingual surfaces than on the buccal in these individuals, confirming a common clinical assumption.

Enamel erosion depths measured on impressions by a white light interferometer.

OBJECTIVE: To investigate if measurements of the step heights on an impression of eroded enamel surfaces may give reliable values of the etching depths measured directly on the enamel. MATERIALS AND METHODS: Twelve human enamel specimens, with one circular amalgam reference surface in each, were mounted on an epoxy block and ground flat. Baseline images were taken by a White Light Interferometer (WLI) followed by 12 min etch by 0.01 M HCl, pH 2.2. The mean etch depth on each specimen was calculated from three repeated measurements, both on the specimen surfaces and on the silicone polymer impressions of the surfaces. Paired samples t-test was used when comparing the precision of measurements on enamel vs on impression. RESULTS: The mean lesion depths after 12 min etch measured on the 12 enamel surfaces and impressions were 9.9 µm and 10.6 µm, respectively. The direct and indirect measurements correlated well (r(2) = 0.95), with 7% higher mean etch depth measured on the impressions (p < 0.05). The reliability of three repeated measurements on enamel and impressions expressed by Intra Class Correlation (ICC) were 0.98 and 0.99, respectively. The average relative precisions of three repeated measurements on the 12 tooth and impression surfaces were (0.5 ± 0.1)% and (0.1 ± 0.02)%, respectively (p < 0.05). The accuracies were 0.4% and 7%, respectively. CONCLUSION: WLI gave reliable but slightly higher etch depth measurements on impressions compared to enamel surfaces.