Microleakage of adhesively bonded cervical amalgam restorations

Purpose: To evaluate dye penetration in adhesively bonded cervical amalgam restorations. Materials and Methods: the specimens were randomly divided into four groups and the adhesives Prime & Bond 2. 1, Prime & Bond 2.1 Dual Cure, Scotchbond Multi Purpose Plus and Amalgambond Plus were tested. After being restored and polished, the teeth were thermocycled 1,000 times at temperatures varying between 5degreesC +/- 2degreesC and 55degreesC +/- 2degreesC. Statistical analysis was carried out using the Kruskal-Wallis test and multiple comparisons. Results: Scotchbond Multi-Purpose Plus demonstrated lower levels of microleakage in enamel and dentin. The dual adhesives were more effective than the one bottle adhesive.

Effect of light-curing units on microleakage under dental composite resins

The aim of this study was to determine the effect of two light-curing units (QTH and LED) on microleakage of Class II composite resin restorations with dentin cavosurface margins. Twenty extracted mandibular first premolars, free of caries and fractures were prepared two vertical slot cavities in the occluso-mesial and -destal surfaces (2 mm buccal-lingually, 2 mm proximal-axially and cervical limit in enamel) and divided into 4 equal groups (n = 8): GI and GII: packable posterior composite light-activated with LED and QTH, respectively; GIII and GIV: micro-hybrid composite resin light-activated with LED and QTH, respectively. The composite resins were applied following the manufacturer's instructions. After 24 h of water storage specimens were subjected to thermocycling for a total of 500 cycles at 5 and 55A degrees C and the teeth were then sealed with impermeable material. Teeth were immersed in 0.5% Basic fuchsin during 24 h at room temperature, and zero to three levels of penetration score were attributed. The Mann-Whitney and Kruskal-Wallis tests showed significant statistically similar (P > 0.05) from GI to GII and GIII to GIV, which the GII (2.750) had the highest mean scores and the GIII and GIV (0.875) had lowest mean scores. The use of different light-curing units has no influence on marginal integrity of Class II composite resin restorations and the proprieties of composite resins are important to reduce the microleakage.

TIME-COURSE DIFFUSION of HYDROGEN PEROXIDE USING MODERN TECHNOLOGIES

The concern with the hydrogen penetration towards the pulp can be observed on the literature by the great number of papers published on this topic; Those measurements often uses chemical agents to quantify the concentration of the bleaching agent that cross the enamel and dentin. The objective of this work was the quantification of oxygen free radicals by fluorescence that are located in the interface between enamel and dentin. It was used to accomplish our objectives a Ruthenium probe (FOXY R - Ocean Optics(R)) a 405nm LED, a bovine tooth and a portable diagnostic system (Science and support LAB - LAT - IFSC/USP). The fluorescence of the probe is suppressed in presence of oxygen free radicals in function of time. The obtained results clearly shows that the hydrogen peroxide when not catalyzed should be kept in contact with the tooth for longer periods of time.

In Vitro Study of the influence of the pigments of three colored gels over the light distribution of visible light by digital images

Nowadays the real contribution of light on the acceleration of the chemical reaction for the dental bleaching is under incredulity, mostly because the real mechanisms of its contribution still are obscure. Objectives: Determine the influence of pigment of three colored bleaching gels in the light distribution and absorption in the teeth, to accomplish that, we have used in this experiment bovine teeth and three colored bleaching gels. It is well Known that the dark molecules absorb light and increase the local temperature upraising the bleaching rate, these molecules are located in the interface between the enamel and dentin. Methods: This study was realized using an argon laser with 455nm with 150mW of intensity and a LED with the same characteristics, three colored gels (green, blue and red) and to realize the capture of the digital images it was used a CCD camera connected to a PC. The images were processed in a mathematical environment (MATHLAB, R12 (R)). Results: The obtained results show that the color of the bleaching gel influences significantly the absorption of light in the specific sites of the teeth. Conclusions: This poor absorption can be one of the major factors involved with the incredulity of the light contribution on the process that can be observed in the literature nowadays.

Ameloblastic fibro-odontoma: A case report

Ameloblastic fibro-odontoma (AFO) is a rare, benign, slow-growing odontogenic tumor, generally asymptomatic and more prevalent in children and adolescents. We report a case of AFO in the mandible of an eight-year-old Caucasian male patient, and review the literature. Intraoral examination revealed a swelling extending from the deciduous second molar to the retromolar triangle, covered with normal mucosa. A panoramic radiograph showed a large, well-demarcated radiolucency with radiopaque areas. The provisional diagnosis was of AFO, and so an incisional biopsy was performed. Histologically, the lesion was composed of connective tissue resembling the dental papilla, with epithelial strands or islands, as well as denticles and amorphous masses of enamel and dentin consistent with a diagnosis of AFO. Surgical excision and curettage of the lesion were performed. The patient has been monitored for eight years and the lesion has not recurred.

Marginal leakage in Class V cavities pretreated with different laser energy densities

The purpose of the present study was to evaluate in vitro the degree of marginal leakage in Class V cavities involving the cementoenamel junction. Cavities were 4 rum wide and 2 mm deep. The specimens received dentin pretreatment (37% phosphoric acid) followed by the Single Bond (3M) adhesive system application. The 40 specimens were then divided into four groups: Group I (control); Group 2 (Nd:YAG laser at 120 mJ/pulse, frequency of 10 Hz, power of 1.2 W); Group 3 (Nd:YAG laser at 140 mJ/pulse, frequency of 10 Hz, power of 1.4 W); Group 4 (Nd:YAG laser at 160 mJ/pulse, frequency of 10 Hz, power of 1.6 W). The cavities were restored with Z100 composite resin (3M) and light cured at 300-600 mW/cm(2) light intensity. Specimens were thermocycled to 500 cycles from 2-50 degrees C. After that, they were dried and sealed with nail varnish, respecting 1 mm around the restorations, and immersed in 0.5% methylene blue solution for 4 h. After this period, the teeth were rinsed, dried, sectioned, and analyzed in a stereoscopic loupe. The highest leakage scores were considered for each specimen. The results were statistically analyzed by the analysis of variance (ANOVA) Kruskal-Wallis test to the 5% level. For both the enamel and cementum, there was a decrease in marginal leakage with the application of laser energy; no significant differences were observed for Groups 2, 3, and 4. The results also showed a smaller tendency to marginal leakage on the cementum than on the enamel.

Study of microleakage at class V cavities prepared by Er : YAG laser using rewetting surface treatment

Objective: This study was conducted to analyze microleakage in Class V cavity preparation, using rewetting (or not) just after burr or Er:YAG laser preparation of enamel and dentin walls in permanent teeth. Background Data: Several studies reported microleakage around composite restorations when cavity preparation was done or treated by Er:YAG laser. As the hybridized laser is removed when this laser is used to cut dental hard tissue, there is a need for new materials or techniques to minimize gaps and microleakage. Results: Primer solution showed significant effect in enamel and dentin, at the level of 5%, when Er:YAG laser was used as a cutting tool. Using primer solution after phosphoric acid in preparations with the laser, microleakage was similar in degree to when cavities were prepared with the burr. Conclusion: Re-wetting surface just after Er:YAG irradiation and chemical treatment with phosphoric acid using HEMA aqueous solution seems to improve the quality of bioattachment between the adhesive system and enamel/dentin, showing similarities between restoration behaviors independently of the cutting tool, whether burr or laser.

Effect of the clinical application of the GaAlAs laser in the treatment of dentine hypersensitivity

Objective: the aim of this study was to evaluate the effectiveness of the clinical use of the gallium-aluminum-arsenium (GaAlAs) laser at the maximum and minimum energies recommended by the manufacturer for the treatment of dentine hypersensitivity.Background Data: Dentine hypersensitivity (DH) is a response to a stimulus that would not usually cause pain in a healthy tooth. It is characterized by sharp pain of short duration from the denuded dentin. Its etiology is unknown. The dentin only begins to show sensitivity when exposed to the buccal environment. This exposure can result after removal of the enamel and/or dental cement, or after root denudation. Different treatments are proposed for this disorder.Materials and Methods: In this study, 25 patients, with a total number of 106 cases of DH, were treated with GaAlAs low-level laser therapy (LLLT). 65% of the teeth were premolars; 14% were incisors and molars; 6.6% were canines. The teeth were irradiated with 3 and 5 J/cm(2) for up to six sessions, with an interval of 72 It between each application, and they were evaluated initially, after each application, and at 15 and 60 days follow-up post-treatment.Results: the treatment was effective in 86.53% and 88.88% of the irradiated teeth, respectively, with the minimum and maximum energy recommended by the manufacturer. There was a statistically significant difference between DH and after a follow-up of 60 days for both groups. The difference among the energy maximum and minimum was not significant.Conclusion: the GaAlAs low-level laser was effective in reducing initial DH. A significant difference was found between initial values of hypersensitivity and after 60 days follow-up post-treatment. No significant difference was found between minimum (3 J/cm(2)) and maximum (5 J/cm(2)) applied energy.

Effect of the Clinical Application of the GaA1As Laser in the Treatment of Dentine Hypersensitivity

Objective: The aim of this study was to evaluate the effectiveness of the clinical use of the gallium-aluminum-arsenium (GaAlAs) laser at the maximum and minimum energies recommended by the manufacturer for the treatment of dentine hypersensitivity. Background Data: Dentine hypersensitivity (DH) is a response to a stimulus that would not usually cause pain in a healthy tooth. It is characterized by sharp pain of short duration from the denuded dentin. Its etiology is unknown. The dentin only begins to show sensitivity when exposed to the buccal environment. This exposure can result after removal of the enamel and/or dental cement, or after root denudation. Different treatments are proposed for this disorder. Materials and Methods: In this study, 25 patients, with a total number of 106 cases of DH, were treated with GaAlAs low-level laser therapy (LLLT). 65% of the teeth were premolars; 14% were incisors and molars; 6.6% were canines. The teeth were irradiated with 3 and 5 J/cm 2 for up to six sessions, with an interval of 72 h between each application, and they were evaluated initially, after each application, and at 15 and 60 days follow-up post-treatment. Results: The treatment was effective in 86.53% and 88.88% of the irradiated teeth, respectively, with the minimum and maximum energy recommended by the manufacturer. There was a statistically significant difference between DH and after a follow-up of 60 days for both groups. The difference among the energy maximum and minimum was not significant. Conclusion: The GaAlAs low-level laser was effective in reducing initial DH. A significant difference was found between initial values of hypersensitivity and after 60 days follow-up post-treatment. No significant difference was found between minimum (3 J/cm 2) and maximum (5 J/cm 2) applied energy.

Odontomas in pediatric dentistry: Report of two cases

Odontomas are developmental disturbances which manifest in the form of denticles or amorphous informes masses comprising all dental tissues, especially enamel and dentin, with variable amounts of pulp and cement. We describe here two clinical cases of odontomas in children, focusing on diagnostic means and the importance of early treatment of these lesions. The standard treatment for the two present cases was surgical removal.

Cutting characteristics of dental diamond burs made with CVD technology

The aim of this study was to determine the cutting ability of chemical vapor deposition (CVD) diamond burs coupled to an ultrasonic dental unit handpiece for minimally invasive cavity preparation. One standard cavity was prepared on the mesial and distal surfaces of 40 extracted human third molars either with cylindrical or with spherical CVD burs. The cutting ability was compared regarding type of substrate (enamel and dentin) and direction of handpiece motion. The morphological characteristics, width and depth of the cavities were analyzed and measured using scanning electron micrographs. Statistical analysis using the Kruskal-Wallis test (p < 0.05) revealed that the width and depth of the cavities were significantly greater when they were prepared on dentin. Wider cavities were prepared when the cylindrical CVD bur was used, and deeper cavities resulted from preparation with the spherical CVD bur. The direction of handpiece motion did not influence the size of the cavities, and the CVD burs produced precise and conservative cutting.

Radiopacity of restorative materials using digital images

The radiopacity of esthetic restorative materials has been established as an important requirement, improving the radiographic diagnosis. The aim of this study was to evaluate the radiopacity of six restorative materials using a direct digital image system, comparing them to the dental tissues (enamel-dentin), expressed as equivalent thickness of aluminum (millimeters of aluminum). Five specimens of each material were made. Three 2-mm thick longitudinal sections were cut from an intact extracted permanent molar tooth (including enamel and dentin). An aluminum step wedge with 9 steps was used. The samples of different materials were placed on a phosphor plate together with a tooth section, aluminum step wedge and metal code letter, and were exposed using a dental x-ray unit. Five measurements of radiographic density were obtained from each image of each item assessed (restorative material, enamel, dentin, each step of the aluminum step wedge) and the mean of these values was calculated. Radiopacity values were subsequently calculated as equivalents of aluminum thickness. Analysis of variance (ANOVA) indicated significant differences in radiopacity values among the materials (P<0.0001). The radiopacity values of the restorative materials evaluated were, in decreasing order: TPH, F2000, Synergy, Prisma Flow, Degufill, Luxat. Only Luxat had significantly lower radiopacity values than dentin. One material (Degufill) had similar radiopacity values to enamel and four (TPH, F2000, Synergy and Prisma Flow) had significantly higher radiopacity values than enamel. In conclusion, to assess the adequacy of posterior composite restorations it is important that the restorative material to be used has enough radiopacity, in order to be easily distinguished from the tooth structure in the radiographic image. Knowledge on the radiopacity of different materials helps professionals to select the most suitable material, along with other properties such as biocompatibility, adhesion and esthetic.

The effect of temperature on self-etching adhesive penetration.

The purpose of this study was to investigate the penetration of an aggressive self-etching adhesive system at refrigerated and room temperatures into ground and unground enamel surfaces. Thirty extracted human teeth were used to measure adhesive penetration into enamel by light microscopy analysis (x400). The unground enamel surfaces were cleaned with pumice and water using a rotary dental brush. For each specimen, part of the unground enamel was manually ground and part was kept intact. A self-etch adhesive was evaluated for its ability to penetrate ground and unground enamel surfaces at room temperature (25 degrees C), at 30 minutes after removal from the refrigerator, and immediately after removal from the refrigerator (6 degrees C). Data were analyzed using variance and the Tukey test, which revealed significant differences in length of penetration of this material when applied on ground and unground enamel surfaces and between the different temperatures used (P > .05). The self-etching system used in this study had significantly lower penetration into unground enamel and at 6 degrees C (P < .05). No statistical difference was found between the interactions of these factors. It was concluded that the self-etching system produced the best penetration into ground enamel surface at room temperature (25 degrees C) and at 30 minutes after removing the specimens from the refrigerator.

A meniralização dental e a atividade salivar estão reduzidas em filhotes de ratas espontaneamente hipertensas (SHR)

Several pathologies have been diagnosed in children of hypertensive mothers; however, some studies that evaluated the alterations in their oral health are not conclusive. This study analyzed the salivary gland activity and dental mineralization of offsprings of spontaneously hypertensive rats (SHR). Thirty-day-old SHR males and Wistar rats were studied. The salivary flow was evaluated by injection of pilocarpine, the protein concentration and salivary amylase activity, by the Lowry method and kinetic method at 405 nm, respectively. Enamel and dentin mineralization of the mandibular incisors was quantified with aid of the microhardness meter. The results were analyzed by the ANOVA or Student's t test (p<0.05). It was noticed that the salivary flow rate (0.026 mL/min/100 g±0.002) and salivary protein concentration (2.26mg/mL±0.14) of SHR offspring were reduced compared to Wistar normotensive offspring (0.036 mL/min/100 g±0.003 and 2.91 mg/mL±0.27, respectively), yet there was no alteration in amylase activity (SHR: 242.4 U/mL±36.9; Wistar: 163.8 U/mL±14.1). Microhardness was lower both in enamel (255.8 KHN±2.6) and dentin (59.9 KHN±0.8) for the SHR teeth compared to the Wistar teeth (enamel: 328.7 KHN±3.3 and dentin: 67.1 KHN±1.0). These results suggest that the SHR offspring are more susceptible to development of pathologies impairing oral health, once they presented lesser flow and salivary protein concentration and lower dental mineralization.

Tensile bond strength of self-etching versus total-etching adhesive systems under different dentinal substrate conditions

The use of acid etchants to produce surface demineralization and collagen network exposure, allowing adhesive monomers interdiffusion and consequently the formation of a hybrid layer, has been considered the most efficient mechanism of dentin bonding. The aim of this study was to compare the tensile bond strength to dentin of three adhesive systems, two self-etching ones (Clearfil SE Bond - CSEB and One Up Bond F - OUBF) and one total-etching one (Single Bond - SB), under three dentinal substrate conditions (wet, dry and re-wet). Ninety human, freshly extracted third molars were sectioned at the occlusal surface to remove enamel and to form a flat dentin wall. The specimens were restored with composite resin (Filtek Z250) and submitted to tensile bond strength testing (TBS) in an MTS 810. The data were submitted to two-way ANOVA and Tukey's test (p = 0.05). Wet dentin presented the highest TBS values for SB and CSEB. Dry dentin and re-wet produced significantly lower TBS values when using SB. OUBF was not affected by the different conditions of the dentin substrate, producing similar TBS values regardless of the surface pretreatments.