This study assessed the surface softening and abrasive wear of eroded bovine enamel with or without the influence of toothbrushing. Five volunteers took part in this in situ study of 5 days. They wore acrylic palatal appliances containing 6 bovine enamel blocks divided in two rows with 3 blocks, which corresponded to the studied groups: erosion without toothbrushing (GI) and erosion with toothbrushing (GII). The blocks were subjected to erosion by immersion of the appliances in a cola drink for 10 minutes, 4 times a day. After that, no treatment was performed in one row (GI), whereas the other row was brushed (GII). The appliance was then replaced into the mouth. Enamel alterations were determined using profilometry and microhardness tests. Data were tested using paired Student's t test (p < 0.05). The mean wear values (µm) and percentage of superficial microhardness change (%SMHC) were respectively: GI -2.77 ± 1.21/91.61 ± 3.68 and GII -3.80 ± 0.91/58.77 ± 11.47. There was a significant difference in wear (p = 0.001) and %SMHC (p = 0.001) between the groups. It was concluded that the wear was more pronounced when associated to toothbrushing abrasion. However, toothbrushing promoted less %SMHC due to the removal of the altered superficial enamel layer. DESCRIPTORS: Tooth erosion; Tooth abrasion; Beverages. RESUMO:Este estudo avaliou o amolecimento superficial e o desgaste do esmalte bovino erodido com ou sem influência da escovação. Cinco voluntários fizeram parte deste estudo in situ de 5 dias. Eles usaram aparelhos palatinos de acrílico contendo 6 blocos de esmalte bovino divididos em 2 fileiras com 3 blocos, cada fileira correspondeu a um grupo em estudo: erosão sem escovação dentária (GI) e erosão seguida de escovação dentária (GII). Os blocos foram submetidos à erosão por imersão do aparelho em uma bebida à base de cola por 10 minutos, 4 vezes ao dia. Depois disso, nenhum tratamento foi realizado em uma fileira (GI), enquanto a outra fileira foi escovada (GII). Em seguida, o aparelho foi recolocado na boca. Alterações do esmalte foram determinadas por teste de perfilometria e microdureza. Os dados foram analisados usando-se teste t de Student (p < 0,05). O valor médio de desgaste (µm) e da porcentagem de perda de microdureza superficial (%PDS) foi respectivamente: GI -2,77 ± 1,21/91,61 ± 3,68 e GII -3,80 ± 0,91/58,77 ± 11,47. Houve uma diferença estatisticamente significante no desgaste (p = 0,001) e na %PDS (p = 0,001) entre grupos. Conclui-se que o desgaste foi mais pronunciado quando associado à abrasão pela escovação. Entretanto, a escovação promoveu menor %PDS, devido à remoção da camada de esmalte superficial alterada.

The association between APF application and laser irradiation seems to be an alternative preventive measure against dental erosion.

Patients with Vitamin D-resistant rickets have abnormal tooth morphology such as thin globular dentin and enlarged pulp horns that extend into the dentino-enamel junction. Invasion of the pulp by microorganisms and toxins is inevitable. The increased fibrotic content of the pulp, together with a reduced number of odontoblasts, decreases the response to pulp infection. The most important oral findings are characterized by spontaneous gingival and dental abscesses occuring without history of trauma or caries. Radiographic examinations revealed large pulp chambers, short roots, poorly defined lamina dura and hypoplastic alveolar ridge. These dental abscesses are common and therefore the extraction and pulpectomy are the treatment of choice. The purpose of this article is to report a case of Vitamin D-resistant rickets in a 5 year-old boy, describing the dental findings and the treatment to be performed in these cases.

This in situ study investigated, using scanning electron microscopy, the effect of stimulated saliva on the enamel surface of bovine and human substrates submitted to erosion followed by brushing abrasion immediately or after one hour. During 2 experimental 7-day crossover phases, 9 previously selected volunteers wore intraoral palatal devices, with 12 enamel specimens (6 human and 6 bovine). In the first phase, the volunteers immersed the device for 5 minutes in 150 ml of a cola drink, 4 times a day (8h00, 12h00, 16h00 and 20h00). Immediately after the immersions, no treatment was performed in 4 specimens (ERO), 4 other specimens were immediately brushed (0 min) using a fluoride dentifrice and the device was replaced into the mouth. After 60 min, the other 4 specimens were brushed. In the second phase, the procedures were repeated but, after the immersions, the volunteers stimulated the salivary flow rate by chewing a sugar-free gum for 30 min. Enamel superficial alterations of all specimens were then evaluated using a scanning electron microscope. Enamel prism core dissolution was seen on the surfaces submitted to erosion, while on those submitted to erosion and to abrasion (both at 0 and 60 min) a more homogeneous enamel surface was observed, probably due to the removal of the altered superficial prism layer. For all the other variables -enamel substrate and salivary stimulation -, the microscopic pattern of the enamel specimens was similar.