Maria Angela Pita Sobral

In vitro evaluation of the erosive potential of orange juice modified by food additives in enamel and dentine

OBJECTIVES To evaluate the erosive potential of orange juice modified by food additives in enamel and dentine. METHODS Calcium lactate pentahydrate (CLP), xanthan gum (XG), sodium linear polyphosphate (LPP), sodium pyrophosphate tetrabasic (PP), sodium tripolyphosphate (STP) and some of their combinations were added to an orange juice. Pure orange juice and a calcium-modified juice were used as negative (C-) and positive (C+) controls, respectively. In phase 1, 15 modified orange juices were tested for erosive potential using pH-stat analysis. In phase 2, the additives alone and the combination with good results in phase 1 and in previous studies (CLP+LPP) were tested in an erosion-remineralization cycling model. In phase 3, the erosion and remineralization episodes were studied independently. Enamel was analysed by surface microhardness (SMH) and profilometry, whilst dentine by profilometry. RESULTS In phase 1, reduction of the erosive potential was observed for all additives and their combinations, except XG alone. In phase 2, no detectable enamel loss was observed when CLP, LPP and CLP+LPP were added to the juice. XG, STP and PP had enamel loss similar to C- (p>0.05). Amongst additives, the combination CLP+LPP showed the highest SMH values followed by CLP (p<0.05). All the other groups presented SMH values similar to C- (p>0.05). For dentine, only CLP+LPP lead to surface loss values lower than C- (p<0.05). In phase 3, CLP, LPP and CLP+LPP seemed to protect against erosion; whilst none of the tested compounds seemed to interfere with the remineralization process. CONCLUSIONS CLP and LPP reduced erosion on enamel and this effect was enhanced by their combination. For dentine, only the combination CLP+LPP reduced erosion.

Interaction between staining and degradation of a composite resin in contact with colored foods

Composite resins might be susceptible to degradation and staining when in contact with some foods and drinks. This study evaluated color alteration and changes in microhardness of a microhybrid composite after immersion in different colored foods and determined whether there was a correlation between these two variables. Eighty composite disks were randomly divided into 8 experimental groups (n = 10): kept dry; deionized water; orange juice; passion fruit juice; grape juice; ketchup; mustard and soy sauce. The disks were individually immersed in their respective test substance at 37 ºC, for a period of 28 days. Superficial analysis of the disk specimens was performed by taking microhardness measurements (Vickers, 50 g load for 45 seconds) and color alterations were determined with a spectrophotometer (CINTRA 10- using a CIEL*a*b* system, 400-700 nm wavelength, illuminant d65 and standard observer of 2º) at the following times: baseline (before immersion), 1, 7, 14, 21 and 28 days. Results were analyzed by ANOVA and Tukeys test (p < 0.05). Both variables were also submitted to Pearsons correlation test (p < 0.05). The passion fruit group underwent the greatest microhardness change, while the mustard group suffered the greatest color alteration. Significant positive correlation was found between the two variables for the groups deionized water, grape juice, soy sauce and ketchup. Not all color alteration could be associated with surface degradation.

Influência da dieta líquida ácida no desenvolvimento de erosão dental

O objetivo deste trabalho foi estudar a importância do pH da dieta liquida na etiologia e prevencao das lesoes de erosao dental, bem como conhecer o pH de algumas bebidas e sucos, supostamente acidos, mais consumidos em nosso meio, para que fosse possivel estabelecer uma comparacao destes valores a fim de controlar a dieta dos pacientes portadores de lesoes de erosao dental. Um unico exemplar de cada fruta madura foi processado puro de modo a ser liquefeito e o pH foi medido utilizando-se um pH-metro, imediatamente e depois de 30 minutos. Posteriormente, a amostra de suco foi diluida em agua na proporcao de 1:2 e novas medidas foram tomadas. Para as bebidas industrializadas, as medidas de pH foram realizadas imediatamente apos a abertura do frasco e depois de 30 minutos. As bebidas e sucos analisados mostraram valores abaixo do pH critico de dissolucao da estrutura dental, sugerindo a possibilidade de favorecerem a desmineralizacao. A orientacao quanto a dieta acida parece ser um fator importante no tratamento e prevencao das lesoes de erosao dental., v. 14, n. 4, p. 406-410, out./dez. 2000.OobjetivodestetrabalhofoiestudaraimportânciadopHdadietaliquidanaetiologiaeprevencaodaslesiesdeerosaodental, bem como conhecer o pH de algumas bebidas e sucos, supostamente AEcidos, mais consumidos em nosso meio,paraquefossepossivelestabelecerumacomparacaodestesvaloresafimdecontrolaradietadospacientesportadoresde lesies de erosao dental. Um œnico exemplar de cada fruta madura foi processado puro de modo a ser liquefeito e opH foi medido utilizando-se um pH-metro, imediatamente e depois de 30 minutos. Posteriormente, a amostra de sucofoidiluidaemAEguanaproporcaode1:2enovasmedidasforamtomadas.Paraasbebidasindustrializadas,asmedidasde pH foram realizadas imediatamente apos a abertura do frasco e depois de 30 minutos. As bebidas e sucos analisa-dos mostraram valores abaixo do pH critico de dissolucao da estrutura dental, sugerindo a possibilidade de favorece-rem a desmineralizacao. A orientacao quanto a dieta AEcida parece ser um fator importante no tratamento e prevencaodas lesies de erosao dental.UNITERMOS: Erosao de dente; Desmineralizacao do dente; Dieta.

Streptococcus mutans-induced secondary caries adjacent to glass ionomer cement, composite resin and amalgam restorations in vitro

The aim of this study was to define, in vitro, the potential to inhibit secondary caries of restorative materials currently used in dental practice. Standard cavities were prepared on the buccal and lingual surfaces of fifty extracted human third molars. The teeth were randomly divided into five groups, each one restored with one of the following materials: glass ionomer cement (GIC); amalgam; light-cured composite resin; ion-releasing composite; and light-cured, fluoride-containing composite resin. The teeth were thermocycled, sterilized with gamma irradiation, exposed to a cariogenic challenge using a bacterial system using Streptococcus mutans, and then prepared for microscopic observation. The following parameters were measured in each lesion formed: extension, depth, and caries inhibition area. The outer lesions developed showed an intact surface layer and had a rectangular shape. Wall lesions were not observed inside the cavities. After Analysis of Variance and Component of Variance Models Analysis, it was observed that the GIC group had the smallest lesions and the greatest number of caries inhibition areas. The lesions developed around Amalgam and Ariston pHc restorations had an intermediate size and the largest lesions were observed around Z-100 and Heliomolar restorations. It may be concluded that the restorative materials GIC, amalgam and ion-releasing composites may reduce secondary caries formation.

In situ Evaluation of the Erosive Potential of Orange Juice Modified by Food Additives

The aim of this study was to evaluatethe erosive potential of orange juice modified with food-approved additives: 0.4 g/l of calcium (Ca) from calcium lactate pentahydrate, 0.2 g/l of linear sodium polyphosphate (LPP) or their combination (Ca+LPP) were added to a commercially available orange juice (negative control, C–). A commercially available calcium-modified orange juice (1.6 g/l of calcium) was the positive control (C+). These juices were tested using a short-term erosion in situmodel, consisting of a five-phase, single-blind crossover clinical trial involving 10 subjects. In each phase, subjects inserted custom-made palatal appliances containing 8 bovine enamel specimens in the mouth and performed erosive challenges for a total of 0 (control), 10, 20, and 30 min. Two specimens were randomly removed from the appliances after each challenge period. Enamel surface microhardness was measured before and after the clinical phase and the percentage of surface microhardness change (%SMC) was determined. Before the procedures, in each phase, the subjects performed a taste test, where the juice assigned to that phase was blindly compared to C–. Overall, C+ showed the lowest %SMC, being the least erosive solution (p < 0.05), followed by Ca+LPP and Ca, which did not differ from each other (p > 0.05). LPP and C– were the most erosive solutions (p < 0.05). Taste differences were higher for C+ (5/10 subjects) and Ca (4/10 subjects), but detectable in all groups, including C– (2/10 subjects). Calcium reduced the erosive potential of the orange juice, while no protection was observed for LPP.

Effect of Nd:YAG Laser and Acidulated Phosphate Fluoride on Bovine and Human Enamel Submitted to Erosion/Abrasion or Erosion Only: An in Vitro Preliminary Study

OBJECTIVE The aim of the present in vitro study was to evaluate, using two different methodologies, the effectiveness of pulsed Nd:YAG laser irradiation associated with topical acidulated phosphate fluoride (APF) for preventing enamel erosion and structure loss under regimes of erosion and abrasion or erosion only. BACKGROUND DATA An increased incidence of noncarious lesions (erosion and abrasion) has been observed, consequently new preventative therapies have been proposed. MATERIALS AND METHODS Two different methodologies were performed. For the first, 100 bovine crowns were submitted to four different treatments (n = 25): no treatment (control), 4 min application of APF, Nd:YAG laser irradiation (1 W, 100 mJ, 10 Hz, 141.5 J/cm(2)), and Nd:YAG laser irradiation + 4 min of APF. After the specimens were exposed to citric acid (2% w/v; 30 min), they were submitted to 5000 brushing cycles. Specimen mass was measured before and after the treatments. For the second methodology, 20 human crowns were embedded in acrylic resin and cut surfaces were exposed and polished. The specimens were divided into four groups (n = 10): no treatment (control), APF for 4 min, Nd:YAG laser irradiation (1 W, 100 mJ, 10 Hz, 125 J/cm(2)), and Nd:YAG laser irradiation + APF. The samples were then immersed in citric acid (2% w/v; 90 min). Vickers hardness was obtained before and after the treatments. RESULTS The Nd:YAG laser irradiation + APF (bovine and human enamel) was more effective and yielded statistically significant results for surface microhardness and enamel wear. CONCLUSION Nd:YAG laser irradiation associated with APF reduced bovine enamel wear and human enamel softening when samples were submitted to a regime of erosion and abrasion or erosion only in vitro.

Aspectos clínicos da etiologia da hipersensibilidade dentinária cervical

This research was developed with the purpose to study some clinical aspects of cervical dentin hypersensitivity (HSDC). A total of 32 pacients were identified with the HSDC symptom being 97 teeth examined. Based on the anamnesis and clinic examination, the lesions were classified according to the presence of abrasion, erosion or abfraction. The important HSDC related factors were more efficient/frequent hygiene, periodontal treatment, ingestion of acid aliments and oclusion trauma. The most frequent occurances were observed in small lesions in the radicular region. The most affected teeth are bicuspids and the cervical sensitivity is frequently more related to abrasion influence.

Morphological and Mineral Analysis of Dental Enamel After Erosive Challenge in Gastric Juice and Orange Juice

This study evaluated and compared in vitro the morphology and mineral composition of dental enamel after erosive challenge in gastric juice and orange juice. Human enamel specimens were submitted to erosive challenge using gastric juice (from endoscopy exam) (n = 10), and orange juice (commercially‐available) (n = 10), as follows: 5 min in 3 mL of demineralization solution, rinse with distilled water, and store in artificial saliva for 3 h. This cycle was repeated four times a day for 14 days. Calcium (Ca) loss after acid exposure was determined by atomic emission spectroscopy. The presence of carbonate (CO) and phosphate (PO) in the specimens was evaluated before and after the erosive challenge by FT‐Raman spectroscopy. Data were tested using t‐tests (P < 0.05). Morphology of enamel was observed in scanning electron microscopy (SEM). The mean loss of Ca was: 12.74 ± 3.33 mg/L Ca (gastric juice) and 7.07 ± 1.44 mg/L Ca (orange juice). The analysis by atomic emission spectroscopy showed statistically significant difference between erosive potential of juices (P = 0.0003). FT‐Raman spectroscopy found no statistically significant difference in the ratio CO/PO after the erosive challenge. The CO/PO ratios values before and after the challenge were: 0.16/0.17 (gastric juice) (P = 0.37) and 0.18/0.14 (orange juice) (P = 0.16). Qualitative analysis by SEM showed intense alterations of enamel surface. The gastric juice caused more changes in morphology and mineral composition of dental enamel than orange juice. The atomic emission spectroscopy showed to be more suitable to analyze small mineral loss after erosive challenge than FT‐Raman. Microsc. Res. Tech., 2011.

Clinical features and factors associated with non-carious cervical lesions and dentin hypersensitivity.

Determining the factors associated with NCCLs and DH in populations could guide the implementation of specific preventive measures. This study evaluated the clinical features and factors associated with non-carious cervical lesions (NCCLs) and dentin hypersensitivity (DH) in a Brazilian population. The participants were 118 patients at the Dentistry Clinic of our dental school. They completed an interview to obtain personal information and determine the possible factors associated with NCCLs and DH. Clinical examination was undertaken to record the NCCLs, shape of the lesion and certain occlusal factors. DH was diagnosed by air and probe tests. Data were analysed with the multilevel Poisson regression and prevalence ratios, and the respective 95% confidence intervals were calculated. The prevalence of NCCLs and DH among patients was 67·8% and 51·7%, respectively. Of a total number of 2902 teeth examined, 9·65% had NCCLs and 5·82% were sensitive to air. The most affected teeth for both conditions were the premolars. Most of the NCCLs were wedge-shaped and located in the maxilla. The factors associated with NCCLs and DH were age and presence of premature occlusal contacts. NCCLs were also significantly associated with consumption of wine and alcoholic beverages, and DH with consumption of acidic fruits and juices. NCCLs were a common finding, with higher frequency in more advanced age groups, the maxilla and premolars. A significant association occurred between NCCLs, premature contacts and consumption of wine and alcoholic beverages. DH was associated with NCCLs, premature contacts and with the consumption of acidic fruits and juices.

Development of an orange juice surrogate for the study of dental erosion

The aim of this study was to create a synthetic juice (SJ) to be used as a surrogate for natural orange juices in erosion studies, verifying its erosive potential. The SJ was formulated based on the chemical composition of orange juices from different locations. Forty enamel and 40 root dentin specimens were randomly assigned into 4 experimental groups (n = 10): SJ; 1% Citric Acid (CA); Minute Maid Original® (MM) and Florida Natural Original® (FN). The specimens were immersed in their respective solutions for 5 min, 6x/day for 5 days, in an erosion-remineralization cycling model. Enamel specimens were analyzed by surface Knoop microhardness and optical profilometry and dentin specimens only by optical profilometry. Outcomes were analyzed statistically by ANOVA followed by Tukeys test considering a significance level of 5%. For enamel, the surface loss and microhardness changes found for MM and SJ groups were similar (p>0.05) and significantly lower (p<0.01) than those found in the CA group. For dentin, CA promoted significantly greater (p<0.01) surface loss compared with all the other groups. No significant difference (p>0.05) was observed in dentin surface loss between MM and SJ. In conclusion, CA was the most erosive solution, and SJ had a similar erosive potential to that of MM natural orange juice.