Salete Moura Bonifácio da Silva

Effect of Salivary Stimulation on Erosion of Human and Bovine Enamel Subjected or Not to Subsequent Abrasion: An in situ/ex vivo Study

This in situ/ex vivo study evaluated whether saliva stimulated by chewing gum could prevent or reduce the wear and the percent change in microhardness (%SMH) of bovine and human enamel submitted to erosion followed by brushing abrasion immediately or after 1 h. 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 min in 150 ml of cola drink, 4 times per day (at 8, 12, 16 and 20 h). Immediately after the immersions, no treatment was performed in 4 specimens, 4 other specimens were immediately brushed (0 min) using a fluoride dentifrice, and the device was replaced into the mouth. After 60 min, the remaining 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. Changes in wear and %SMH were measured. ANOVA and Tukey’s test showed statistical differences (p < 0.05) for the following comparisons. The chewing gum promoted less wear and %SMH. A decreasing %SMH and an increasing enamel wear were observed in the following conditions: erosion only, 60 min and 0 min. The human enamel presented greater %SMH and less wear compared to bovine enamel. The data suggest that the salivary stimulation after an erosive or erosive/abrasive attack can reduce the dental wear and the %SMH.

Influence of toothbrushing on enamel softening and abrasive wear of eroded bovine enamel: an in situ study.

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 Students t test (p < 0.05). The mean wear values (microm) 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.

Analysis of Fingernails and Urine as Biomarkers of Fluoride Exposure from Dentifrice and Varnish in 4- to 7-Year-Old Children

The use of fingernails and urine as biomarkers of exposure to fluoride (F) from fluoridated dentifrice and varnish was evaluated in twenty 4- to 7-year-old children, who were divided into two groups: group A (9 caries-free children) and group B (11 children with past caries experience). They used a placebo dentifrice for 28 days, fluoridated dentifrice (1,570 ppm F) for the following 28 days, and placebo dentifrice for an additional 28 days, then returned to their usual dentifrices. Group B children also received 4-week applications of a varnish (2.26% F) while using the fluoridated dentifrice. Urinary collections were performed 24 h before the use of fluoridated dentifrice and 24 h (group A) or 48 h (group B) after. Fingernails were clipped every 2 weeks, for 26 weeks. Total F intake from diet and dentifrice was estimated. Fingernail F concentrations did not vary significantly throughout the study. Twenty-four-hour urinary F outputs (mean ± SD, µg) were: 414 ± 200 and 468 ± 253 for placebo and F dentifrices, respectively (group A) and 402 ±206, 691 ± 345, 492 ± 243 for placebo dentifrice, F dentifrice plus F varnish and F dentifrice, respectively (group B). The use of F dentifrice did not cause a significant increase in the urinary F output. However, when F varnish was used, a transitory increase in the urinary F output was detected (p = 0.001), returning to baseline levels in the last 24 h. Thus, F varnish is a safe method for topical F application even in children that use F dentifrice regularly. According to our protocol, urine was a suitable biomarker of exposure to F from dentifrice plus varnish, but not from dentifrice alone, while nails were not.

Scanning electron microscopic study of the in situ effect of salivary stimulation on erosion and abrasion in human and bovine enamel

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.

Fluoride Uptake by Plaque from Water and from Dentifrice

It has been suggested that fluoride retention in plaque is limited by available binding sites. We determined the effects of fluoridated or placebo dentifrices on plaque and salivary fluoride concentrations [F]s in communities with different water fluoride concentrations (0.04, 0.85, 3.5 ppm). After one week of dentifrice use, samples were collected 1.0 and 12 hrs after the last use of dentifrices. After the use of fluoridated dentifrice, plaque fluoride concentrations were higher at both times, except at 12 hrs in the 3.5-ppm community. Plaque concentrations at 1.0 hr after the use of fluoridated dentifrice increased almost constantly (6.5 mmol/kg), but then decreased approximately 50% at 12 hrs in each community. Unlike previous studies, the present findings suggest that the use of fluoridated dentifrice is likely to increase plaque fluoride concentrations significantly for up to 12 hrs in areas where the water contains fluoride close to 1.0 ppm. As previously reported, plaque fluoride concentrations were directly related to calcium concentrations.

In Vitro Evaluation of Enamel Erosion After Nd:YAG Laser Irradiation and Fluoride Application

OBJECTIVE Previous investigations have demonstrated improved enamel demineralization resistance after laser irradiation. Due to the possibility of a synergistic effect between laser and fluoride, this study investigated the effect of fluoridated agents and Nd:YAG irradiation separately and in combination on enamel resistance to erosion. METHODS One hundred bovine enamel blocks were randomly divided into 10 groups: G1, untreated (control); G2, acidic phosphate fluoride (APF) (1.23% F) for 4 min; G3, fluoride varnish for 6 h (NaF, 2.26%); G4, 0.5 W Nd:YAG laser (250 microm pulse width, 10 Hz, 35 J/cm(2), with uniform velocity for 30 sec in each application); G5, 0.75 W Nd:YAG laser (52.5 J/cm(2)); G6, 1.0 W Nd:YAG laser (70 J/cm(2)); G7, APF + 0.75 W Nd:YAG laser; G8, 0.75 W Nd:YAG laser + APF; G9, fluoride varnish + 0.75 W Nd:YAG laser; and G10, 0.75 W Nd:YAG laser + fluoride varnish. During 10 d the erosive cycle was conducted by immersion of the blocks in Sprite light((R)) for 1 min, followed by immersion in artificial saliva for 59 min. This procedure was consecutively repeated four times per day. In each day, during the remaining 20 h, the blocks were maintained in artificial saliva. The wear was evaluated by profilometry (days 5 and 10). Data were tested by two-way ANOVA and Bonferronis tests (p < 0.05). RESULTS The mean wear at days 5 and 10 was, respectively: G1, 1.83 and 2.67 microm; G2, 1.04 and 2.60 microm; G3, 1.03 and 2.48 microm; G4, 1.13 and 2.47 microm; G5, 1.07 and 2.44 microm; G6, 1.0 and 2.35 microm; G7, 0.75 and 2.27 microm; G8, 0.80 and 2.12 microm; G9, 0.76 and 2.47 microm; and G10, 1.09 and 2.46 microm. At day 5, all the experimental groups presented significant lesser wear when compared to control group. However, at 10 d, only G7 and G8 were still different from control. CONCLUSIONS The association between APF application and laser irradiation seems to be an alternative preventive measure against dental erosion.

Urgency treatment profile of 0 to 15 year-old children assisted at urgency dental service from Bauru Dental School, University of São Paulo

Dental recordings of 0 to 15-year-old patients assisted at Urgency Dental Service (UDS) from Bauru Dental School, University of São Paulo, in 2001 and 2002, were assessed in order to quantify the number of patients that used the service, to determine attendance patterns, and to record the frequency of different types of dental emergencies and their performed treatment. Data were plotted and submitted to a descriptive statistical analysis. Among the total of patients attended at UDS (6020), 1166 (19.37%) were children, with mean age of 9.24 years. Trauma was the cause for 199 (17.06%) of the recorded urgency visits. It occurred more frequently in children between 0 and 3 years of age (34.42%), and between 7 and 12 years of age (18.12%). The main treatments performed were temporary restoration (33.33%) for coronal fracture, and orientation (24.44%) for luxation. Nontraumatic events were the etiology for 967 (82.92%) of the total urgency diagnosis. The most commonly found nontraumatic diagnosis was dental caries lesions (61.75%), followed by problems of eruption or root resorption (14.27%) and bone or soft tissue lesions (6.51%), among others (17.47%). The most frequent treatments performed for caries lesions were: excavation and temporary restoration (39.39%) when there was no abscess, and coronal opening and dressing (40.95%) for caries lesions with abscess. There was an increasing trend in caries lesions prevalence according to the rising of the age, in contrast to trauma prevalence. Treatment for both situations was done according to the indicated protocol for each case.

Clinical management for epidermolysis bullosa dystrophica

Epidermolysis bullosa (EB) consists of a group of genetic hereditary disorders in which patients frequently present fragile skin and mucosa that form blisters following minor trauma. More than 20 subtypes of EB have been recognized in the literature. Specific genetic mutations are well characterized for most the different EB subtypes and variants. The most common oral manifestations of EB are painful blisters affecting all the oral surfaces. Dental treatment for patients with EB consists of palliative therapy for its oral manifestations along with typical restorative and periodontal procedures. The aim of this article is to describe two dental clinical treatments of recessive dystrophic EB cases and their specific clinical manifestations. The psychological intervention required during the dental treatment of these patients is also presented.

Evaluation of superficial microhardness in dental enamel with different eruptive ages

This study evaluated the superficial microhardness of enamel in teeth at different posteruptive ages (before eruption in the oral cavity, 2-3 years after eruption, 4-10 years after eruption and more than 10 years after eruption). The study sample was composed of 134 specimens of human enamel. One fragment of each tooth was obtained from the flattest central portion of the crown to produce specimens with 3 x 3 mm. The enamel blocks were minimally flattened out and polished in order to obtain a flat surface parallel to the base, which is fundamental for microhardness testing. Microhardness was measured with a microhardness tester and a Knoop diamond indenter, under a static load of 25 g applied for 5 seconds. Comparison between the superficial microhardness obtained for the different groups was performed by analysis of Students t test. The results demonstrated that superficial microhardness values have a tendency to increase over the years, with statistically significant difference only between unerupted enamel and that with more than 10 years after eruption. According to the present conditions and methodology, it was concluded that there were differences between the superficial micro-hardness of specimens at different eruptive ages, revealing an increasing mineralization. However, this difference was significant only between unerupted specimens and those with more than 10 years after eruption.

Dental manifestations of patient with Vitamin D-resistant rickets

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.