Dental anomalies of number in the permanent dentition of patients with bilateral cleft lip: Radiographic study

Objective: To radiographically evaluate the prevalence of dental anomalies in patients with complete and incomplete bilateral cleft lip, comparing the prevalence of anomalies between genders and cleft types. Setting: Hospital for Rehabilitation of Craniofacial Anomalies, University of Sao Paulo (HRAC/USP), Bauru, Sao Paulo, Brazil. Participants: 150 randomly selected panoramic radiographs of individuals with complete or incomplete bilateral cleft lip; patient age 12 to 25 years (mean age 13.8 years). Results: Data were statistically analyzed to compare the possible association between presence of hypodontia and supernumerary teeth, according to gender and cleft type. Among the 150 patients evaluated, 80 (53.3%) were male and 70 (46.6%) were female. Since no statistically significant difference was found in hypodontia between genders, data were grouped for analysis, revealing prevalence of 31.6% for complete clefts and 26.8% for incomplete clefts. Concerning supernumerary teeth, the prevalence for the male patients was 28.2% for complete cleft lip and 29.2% for incomplete cleft lip. For female patients, the prevalence was significantly (p = .006) lower for complete cleft lip (17.5%) than for incomplete cleft lip (46.6%). Conclusions: The present results suggest that the prevalence of hypodontia was higher in patients with complete cleft lip, and the prevalence of supernumerary teeth was higher in patients with incomplete cleft lip, in agreement with previous studies.

Evaluating microfossil content of dental calculus from Brazilian sambaquis

To date, limited numbers of dental calculus samples have been analyzed by researchers in diverse parts of the world. The combined analyses of these have provided some general guidelines for the analysis of calculus that is non-destructive to archaeological teeth. There is still a need for a quantitative study of large numbers of calculus samples to establish protocols, assess the level of contamination, evaluate the quantity of microfossils in dental calculus, and to compare analysis results with the literature concerning the biology of calculus formation. We analyzed dental calculus from 53 teeth from four Brazilian sambaquis. Sambaquis are the shell-mounds that were established prehistorically along the Brazilian coast. The analysis of sambaqui dental calculi shows that there are relatively high concentrations of microfossils (phytoliths and starch), mineral fragments, and charcoal in dental calculus. Mineral fragments and charcoal are possibly contaminants. The largest dental calculi have the lowest concentrations of microfossils. Biologically, this is explained by individual variation in calculus formation between people. Importantly, starch is ubiquitous in dental calculus. The starch and phytoliths show that certainly Dioscorea (yam) and Araucaria angustifolia (Parana pine) were eaten by sambaqui people. Araceae (arum family), Ipomoea batatas (sweet potato) and Zea mays (maize) were probably in their diet. (C) 2009 Elsevier Ltd. All rights reserved.

Efficient but destructive: a test of the dental wash technique using secondary electron microscopy

The Boyadjian et al dental wash technique provides, in certain contexts, the only chance to analyze and quantify the use of plants by past populations and is therefore an important milestone for the reconstruction of paleodiet. With this paper we present recent investigations and results upon the influence of this method on teeth. A series of six teeth from a three thousand years old Brazilian shellmound (Jabuticabeira II) was examined before and after dental wash. The main focus was documenting the alteration of the surfaces and microstructures. The status of all teeth were documented using macrophotography, optical light microscopy, and atmospheric Secondary Electron Microscopy (aSEM) prior and after applying the dental wash technique. The comparison of pictures taken before and after dental wash showed the different degrees of variation and damage done to the teeth but, also, provided additional information about microstructures, which have not been visible before. Consequently we suggest that dental wash should only be carried out, if absolutely necessary, after dental pathology, dental morphology and microwear studies have been accomplished. (C) 2010 Elsevier Ltd. All rights reserved.

Genotoxic effects of X-rays on keratinized mucosa cells during panoramic dental radiography

Objectives: The aim of this study was to evaluate the genotoxic effects of X-rays on epithelial gingival cells during panoramic dental radiography using a differentiated protocol for the micronucleus test. Methods: 40 healthy individuals who underwent this procedure for diagnostic purposes on request from their dentists agreed to participate in this study. All of them answered a questionnaire before the examination. Epithelial gingival cells were obtained from the keratinized mucosa of the upper dental arcade by gentle scraping with a cervical brush immediately before exposure and 10 days later. Cytological preparations were stained according to the Feulgen-Rossenbeck reaction, counterstained with fast green 1% for 1 min and analysed under a light microscope. Micronuclei, nuclear projections (broken eggs) and degenerative nuclear alterations (pyknosis, karyolysis, karyorrhexis and condensed chromatin) were scored. Results: The frequency of micronuclei was significantly higher after exposure (P < 0.05), as were frequencies of nuclear alterations indicate of apoptosis (P < 0.001). Conclusions: These results indicate that X-ray radiation emitted during panoramic dental radiography induces a genotoxic effect on epithelial gingival cells that increases the frequency of chromosomal damage and nuclear alterations indicative of apoptosis.

Dental anxiety and trait anxiety: an investigation of their relationship

Background Anxiety related to dental treatment is a fairly common phenomenon. Some studies have shown that there is an association between dental anxiety and general fears and anxiety, neuroticism and general psychological distress. Aim This study was designed to examine the relationship between dental anxiety and trait anxiety. Subjects and methods The sample consisted of 1,030 individuals (688 women; 342 men), aged 30.8 +/- 11.7 years. The Portuguese version of Corah`s Dental Anxiety Scale (DAS) and State-Trait Anxiety Inventory (STAI-T) were used. Results A statistically significant association between high DAS and high STAI-T, but not between high STAI-T and high DAS, was found. The data indicated that subjects with high dental anxiety tend to present with high trait anxiety, but high trait anxiety seems not to predispose to high dental anxiety. Conclusions Our results indicate that dental anxiety is specific, with its own features, and its development is not necessarily associated with trait anxiety.

Occurrence of herpes simplex virus 1 and three periodontal bacteria in patients with chronic periodontitis and necrotic pulp

Viral and bacterial associations appear to be implicated in the development of periodontal infections. Little information is available describing the periodontopathic agents in root canals with necrotic pulp. In this study, the occurrence and the combinations among herpes simplex virus type 1 (HSV-1) and Dialister pneumosintes, Tannerella forsythia.. and Treponema denticola in patients with chronic periodontitis and necrotic pulp were evaluated. Clinical samples from healthy subjects and patients with periodontal or pulp infections were analyzed using a nested polymerase chain reaction PCR to detect HSV and PCR to detect the 3 periodontal bacteria. The presence of Tannerella forsythia and Treponema denticola was observed in healthy, periodontitis, and necrotic pulp patients. HSV was observed in periodontitis and necrotic pulp patients, and no healthy subject harbored D. pneumosintes or HSV. The occurrence of Tannerella forsythia was not statistically significant in patients with necrotic pulp (P = 0.704). Periodontal bacteria were observed varying from 10.3% to 20.7% in periodontitis and necrotic pulp patients. The presence of Treponema denticola - HSV association was predominant in patients showing necrotic pulp (24.1%); however, HSV alone was observed in one patient with periodontitis and in another patient with necrotic pulp. The presence of double association among bacteria or bacteria - HSV could indicate a role in both periodontitis and necrotic pulp, and Tannerella forsythia - Treponenta denticola - HSV and Tannerella forsythia - D. pneumosintes - Treponema denticola - HSV associations might be important in periodontitis.

Some factors associated with dental caries in the primary dentition of children with Down syndrome

Aim It is well reported in the scientific literature that there is a high level of periodontal disease and lower caries prevalence in Down Syndrome (DS) individuals, when compared with age-matched non DS individuals. This study was conducted to investigate the process of dental caries in DS children. Materials and methods In this study the following parameters were considered: oral hygiene habits, levels of Streptococcus mutans (SM) and Lactobacillus spp. (LB), Modified Gingival Index (MGI), and Simplified Oral Hygiene Index (OHI-S). A case group with DS children (n=69) and a control group of non DS children (n=69) were formed to perform this study Dental caries severity was determined using the DMFT index. Samples of non-stimulated saliva were collected to determine the Lactobacillus spp levels. For SM levels, MSB agar plates were used. Results The findings revealed that the case group attended, dental check-ups more frequently brushed their teeth more times per day, flossed less, and also more frequently had SM levels classified as ""high count"". The MGI was higher and the OHI-S was lower than the control group (p<0.001). Conclusion No significant differences were found between the DMFT indexes of children from the two groups (p=0.345). The logistic regression analysis showed that in the case group, age, MGI, and SM count were positively related to dental caries (p<0.05).

Determination of dental decay rates with optical coherence tomography

We report the use of optical coherence tomography (OCT) to detect and quantify demineralization process induced by S. mutans biofilm in third molars human teeth. Artificial lesions were induced by a S. mutans microbiological culture and the samples (N = 50) were divided into groups according to the demineralization time: 3, 5, 7, 9, and 11days. The OCT system was implemented using a light source delivering an average power of 96 mu W in the sample arm, and spectral characteristics allowing 23 mu m of axial resolution. The images were produced with lateral scans step of 10 pan and analyzed individually. As a result of the evaluation of theses images, lesion depth was calculated as function of demineralization time. The depth of the lesion in the root dentine increased from 70 pm to 230,urn (corrected by the enamel refraction index, 1.62 @ 856 nm), depending of exposure time. The lesion depth in root dentine was correlated to demineralization time, showing that it follows a geometrical progression like a bacteria growth law. [GRAPHICS] Progression of lesion depth in root dentine as function of exposure time, showing that it follows a geometrical progression like a bacteria growth law(C) 2009 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA

AFM analysis of bleaching effects on dental enamel microtopography

The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 mu m x 15 mu m area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum(380-750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment. (C) 2009 Elsevier B. V. All rights reserved.

Thermal and structural properties of commercial dental resins light-cured with blue emitting diodes (LEDs)

We have investigated the thermal and structural properties of different commercial dental resins: Filtek(TM) Z-350, Grandio(A (R)), Tetric Ceram(A (R)), and TPH Spectrum(A (R)). The purpose of the present study was to evaluate quantitatively the photo-polymerization behavior and the effect of filler contents on the kinetic cures of the dental resins by using Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. We have successfully obtained the low and high glass transition T (g) values of the dental composite resins from DSC curves. It was also observed a good agreement between the both T (g) values, activation energies from thermal degradation, and the degree of conversion obtained for all samples. The results have shown that Tetric Ceram(A (R)) dental resin presented the higher T (g) values, activation energy of 215 +/- A 6 KJ mol(-1), and the higher degree of conversion (63%) when compared to the other resins studied herein.

Bond Strength of Dental Adhesive Systems Irradiated with Ionizing Radiation

Purpose: The aim of the present paper was to determine the effect of different types of ionizing radiation on the bond strength of three different dentin adhesive systems. Materials and Methods: One hundred twenty specimens of 60 human teeth (protocol number: 032/2007) sectioned mesiodistally were divided into 3 groups according to the adhesives systems used: SB (Adper Single Bond Plus), CB (Clearfil SE Bond) and AP (Adper Prompt Self-Etch). The adhesives were applied on dentin and photo-activated using LED (Lec 1000, MMoptics, 1000 mW/cm(2)). Customized elastomer molds (0.5 mm thickness) with three orifices of 1.2 mm diameter were placed onto the bonding areas and filled with composite resin (Filtek Z-250), which was photo-activated for 20 s. Each group was subdivided into 4 Subgroups for application of the different types of ionizing radiation: ultraviolet radiation (UV), diagnostic x-ray radiation (DX), therapeutic x-ray radiation (TX) and without irradiation (control group, CG). Microshear tests were carried out (Instron, model 4411), and afterwards the modes of failure were evaluated by optical and scanning electron microscope and classified using 5 scores: adhesive failure, mixed failures with 3 significance levels, and cohesive failure. The results of the shear bond strength test were submitted to ANOVA with Tukey`s test and Dunnett`s test, and the data from the failure pattern evaluation were analyzed with the Mann Whitney test (p = 0.05). Results: No change in bond strength of CB and AP was observed after application of the different radiation types, only SB showed increase in bond strength after UV (p = 0.0267) irradiation. The UV also changed the failure patterns of SB (p = 0.0001). Conclusion: The radio-induced changes did not cause degradation of the restorations, which means that they can be exposed to these types of ionizing radiation without weakening the bond strength.

FT-IR spectroscopy assessment of aesthetic dental materials irradiated with low-dose therapeutic ionizing radiation

The aim of the present study was to evaluate the effects of low-dose therapeutic ionizing radiation on different aesthetic dental materials. Forty five specimens (n = 45) of three different aesthetic restorative materials were prepared and randomly divided into five groups: G1 (control group); G2, G3, G4, G5 experimental groups irradiated respectively with 0.25, 0.50, 0.75, and 1.00 Gy of gamma radiation by the (60)Co teletherapy machine. Chemical analyses were performed using a FT-IR Nicolet 520 spectrophotometer with reflectance diffuse technique. Even a minimal exposition at ionizing radiation in therapeutic doses can provide chemical changes on light-cured composite resins. The three studied restorative materials showed changes after exposure at gamma radiation, however the increase of the radiation dose did not contribute to an increase in this effect.

Thermal analysis and structural investigation of different dental composite resins

The structural and thermal properties of three different dental composite resins, Filtek (TM) Supreme XT, Filtek (TM) Z-250 and TPHA (R)(3) were investigated in this study. The internal structures of uncured and cured resins with blue light-emitting diodes (LEDs) were examined by Micro-Raman spectroscopy. Thermal analysis techniques as DSC, TG and DTG methods were used to investigate the temperature characteristics, as glass transition (T (g) ), degradation, and the thermal stability of the resins. The results showed that the TPHA (R)(3) and Filtek (TM) Supreme XT presented very similar T (g) values, 48 and 50A degrees C, respectively, while the Filtek (TM) Z-250 composite resin presented a higher one, 58A degrees C. AFM microscope was utilized in order to analyze the sample morphologies, which possess different fillers. The composed resin Filtek (TM) Z-250 has a well interconnected more homogeneous morphology, suggesting a better degree of conversion correlated to the glass phase transition temperature. The modes of vibration of interest in the resin were investigated using Raman spectroscopy. It was possible to observe the bands representative for the C=C (1630 cm(-1)) and C=O(1700 cm(-1)) vibrations were studied with respect to their compositions and polymerization. It was observed that the Filtek (TM) Z -250 resin presents the best result related to the thermal properties and polymerization after light curing among the other resins.

Femtosecond laser ablation on dental hard tissues-Analysis of ablated profile near an interface using local effective intensity

This study evaluated the process of ablation produced by a Ti:Sapphire femtosecond laser under different average powers taking place at the enamel/dentin interface. Based on the geometry of ablated microcavities the effective intensity for ablation was obtained. This study shows the validity for the local effective intensity analysis and allows a quantification of the variation in the ablation geometry taking place at the interface of two naturally different materials. It shows that the variation of the diameter of the ablated region as a function of the cavity depth comes essentially from a mechanism of effective intensity attenuation, as a result of a series of complex effects. Additionally, our data are sufficient to predict that a discontinuity on the ablation profile will occur on the interface between two biological media: enamel-dentin, showing a suddenly jump on the ablated cavity dimensions.

Effect of power densities and irradiation times on the degree of conversion and temperature increase of a microhybrid dental composite resin

The different parameters used for the photoactivation process provide changes in the degree of conversion (DC%) and temperature rise (TR) of the composite resins. Thus, the purpose of this study was to evaluate the DC (%) and TR of the microhybrid composite resin photoactivated by a new generation LED. For the KBr pellet technique, the composite resin was placed into a metallic mould (1-mm thickness and 4-mm diameter) and photoactivated as follows: continuous LED LCU with different power density values (50-1000 mW/cm(2)). The measurements for the DC (%) were made in a FTIR Spectrometer Bomen (model MB-102, Quebec-Canada). The spectroscopy (FTIR) spectra for both uncured and cured samples were analyzed using an accessory for the diffuse reflectance. The measurements were recorded in the absorbance operating under the following conditions: 32 scans, 4-cm(-1) resolution, and a 300 to 4000-cm(-1) wavelength. The percentage of unreacted carbon-carbon double bonds (% C=C) was determined from the ratio of the absorbance intensities of aliphatic C=C (peak at 1638 cm(-1)) against an internal standard before and after the curing of the specimen: aromatic C-C (peak at 1608 cm-1). For the TR, the samples were made in a metallic mould (2-mm thickness and 4-mm diameter) and photoactivated during 5, 10, and 20 s. The thermocouple was attached to the multimeter to allow the temperature readings. The DC (%) and TR were calculated by the standard technique and submitted to ANOVA and Tukey`s test (p < 0.05). The degree of conversion values varied from 35.0 (+/- 1.3) to 45.0 (+/- 2.4) for 5 s, 45.0 (+/- 1.3) to 55.0 (+/- 2.4) for 10 s, and 47.0 (+/- 1.3) to 52.0 (+/- 2.4) for 20 s. For the TR, the values ranged from 0.3 (+/- 0.01) to 5.4 (+/- 0.11)degrees C for 5 s, from 0.5 (+/- 0.02) to 9.3 (+/- 0.28)degrees C for 10 s, and from 1.0 (+/- 0.06) to 15.0 (+/- 0.95)degrees C for 20 s. The power densities and irradiation times showed a significant effect on the degree of conversion and temperature rise.