The potential for dental plaque to protect against erosion using an in vivo-in vitro model - A pilot study

The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: Tooth erosion is a problem for professional wine tasters (exogenous erosion from frequent exposure to wine acids) and for people with gastro oesophageal reflux disease (GORD) and bulimia who experience frequent reflux of gastric contents into the mouth (endogenous erosion from mainly HCl). The objective in this study was to determine whether plaque/pellicle could provide teeth with any protection from two common erosive acids, using an in vivo-in vitro technique. Methods: Tiles of human tooth enamel and root surfaces were prepared from six extracted, unerupted third molar teeth and sterilized. Mandibular stents were prepared for six volunteer subjects and the tiles bonded to the buccal flanges of these stents. They were worn initially for three days to permit a layer of pellicle and plaque to form over the tile surfaces, and for a further 10 days of experimentation. Following cleaning of the plaque/ pellicle layer from the tiles on the right side flange, all the tiles were submerged in either 0.06M HCl or white wine for an accumulated time of 600 and 1500 minutes, respectively. Depths of erosion were determined using light microscopy of sections of the enamel and root tiles. SEM of the lesion surfaces was carried out to investigate the nature of erosive damage and of plaque/pellicle remnants. Results: Retained plaque was found to significantly inhibit dental erosion on enamel, from contact with both HCl and wine, compared with that resulting following its removal. However, it was found to provide no significant protection on root surfaces. SEM analysis of the tile surfaces revealed marked etching of enamel on the cleaned surfaces, and considerable alteration to the appearance of remaining plaque and pellicle on most surfaces. Conclusion: Within the limitations of numbers of specimens, dental plaque/pellicle provided a significant level of protection to tooth enamel against dental erosion from simulated gastric acids and from white wine, using an in vivo-in vitro model. It was unable to provide any significant protection to root surfaces from these erosive agents. Possible reasons for this difference are explored.A Cheung, Z Zid, D Hunt and J McIntyr

Studies on dental erosion: An in vivo-in vitro model of endogenous dental erosion - its application to testing protection by fluoride gel application

The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: The objective in this study was to develop an in vivo-in vitro model of endogenous erosion, with a view to exploring the potential for some degree of its control by the use of topical fluoride gel application to teeth. Methods: Six volunteers each wore a small clasp retained palatal acrylic appliance to which six sterilized enamel tiles were bonded. Three tiles on each appliance were coated extra-orally with either 1.23 per cent acidulated phosphate fluoride (APF) or 2.2 per cent sodium fluoride (NaF) neutral gel for four minutes prior to multiple periods of exposure to the simulated gastric acid, cumulating in 16, 36, 80 and 150 minutes of exposure. Impressions of the enamel tiles prior to and following acid exposure permitted dies to be prepared. These were sectioned through the exposed areas and examined under a stereomicroscope to assess maximum depths of erosion. Results: The depth of erosive demineralization of enamel was found to be greatly reduced with increased frequency of APF gel application. The reduction in enamel loss was less following topical application of NaF gel. Conclusions: It was concluded that fluoride gels significantly reduced enamel erosion using this in vivo-in vitro model and therefore, if prescribed appropriately, should help reduce tooth tissue loss from endogenous erosion.L Jones, D Lekkas, D Hunt, J McIntyre and W Rafi

Idiopathic cervical lesions: in vivo investigation by oral microendoscopy and scanning electron microscopy. A pilot study

The development and progression of cervical lesions have not been thoroughly documented. Clinically, two morphologically distinct forms, saucer‐or wedge‐shaped, have been described. In this study, the micromorphology of manifest cervical lesions was documented in six subjects, by SEM replication and microendoscopy. Optoelectronic recordings were made of extreme mandibular lateral excursions. Salivary parameters were evaluated and a detailed case history, including oral hygiene and dietary habits, was taken. Lesions of varying severity could be observed in the same subject. Longitudinal fractures of the enamel were common. The dietary analyses were uneventful and salivary values were normal. No correlation was found between brushing habits and the location and severity of the lesions. The optoelectronic recordings, however, indicated a possible correlation between irregular lateral excursion and the severity and location of the lesions, with a tendency for fewer and less severe lesions on the preferred chewing side. The results have indicated some areas of interest for future studies applying non‐invasive observation methods