The influence of grain size coating and shaft angulation of different diamond tips on dental cutting

Objectives: To evaluate the influence of the grain size coating and shaft angulation of ultrasonic and high-speed diamond burs on the dental cutting effectiveness. Materials and Methods: For the grain size evaluation, cavities were prepared on 40 incisors using high-speed (1092 and 1093F KG Sorensen®) and ultrasonic tips (8.2142 and 6.2142-CVDentus®). For the shaft angulation evaluation, cavities were prepared on 40 incisors using uniangulated (T1-CVDentus®) and biangulated (T1-A CVDentus®) ultrasonic tips. The cavities were bisected and examined at 50 magnification. The width and depth of cavities were measured by Leica QWin software. Kruskal-Wallis non-parametric test was used for analysis. Results: The grain size did not affect the cutting effectiveness, but the high-speed burs promoted deeper and wider cavities than the ultrasonic tips. The shaft angulation did not affect the cutting effectiveness; both the angulated and biangulated tips had greater cutting efficiency in dentin than in enamel. Conclusions: Ultrasonic tips promoted more conservative preparations and seemed promising for cavity preparation.

Avaliação dos contatos oclusais em próteses provisórias unitárias implantossuportadas confeccionadas com e sem arco facial

To assess the number of occlusal contacts achieved in temporal prostheses mounted in a semi-adjusted articulator using the facial arch and the Camper plane. Ten patients treated in a private clinic were selected to be rehabilitated with prostheses in previously placed single implants. For each patient two temporal prostheses were designed obtained under different conditions: (1) model mounting using facial arch and (2) Camper plane mounting. Prostheses were made and adjusted in the laboratory and placed only by an operator. The occlusal contacts achieved in each condition were photographed being assessed and quantified by a second professional not involved with the mounting conditions. Results obtained were analyzed by Mann-Whitney test with a 5 % significance level. There was not a statistically difference between the number of occlusal contacts when prostheses were made with facial arch or Camper plane (p= 0.113). The temporal dental prosthesis confection for single implants, semi-adjusted articulator using the Camper plane, not differ very much from the facial arch use, according to the number of resulting occlusal contacts.

Analysis of the effects of thermal cycling on the microtensile shear bond strength of a self-etching and a conventional pit and fissure sealants to dental enamel

Objective: To analyze the effects of thermal cycling on the microtensile shear bond strength of a self-etching and a conventional pit and fissure sealants to dental enamel. Material and Method: Twenty-four healthy human molars extracted for orthodontic reasons, were sectioned in the mesio-distal direction and divided into two groups (n=24) according to the sealant to be applied: GI - conventional sealant Climpro (3M/ESPE) and GII - self-etching sealant Enamel Loc (Premier Dental). The sealants were applied on flattened enamel in matrixes 1 mm in diameter, in accordance with the manufacturers' recommendations. The specimens were stored in distilled water at 37°C for 24 hours. After this, half the samples of both groups were submitted to 500 thermal cycles in 30s baths at temperatures between 5 and 55°C. Forty-eight hours after the samples were made, the microtensile shear test was performed in an Instron 4411 test machine, with a stainless steel wire with a cylindrical cross section of 0.2mm in diameter at a constant speed of 0.5mm/s. The bond strength values were submitted to ANOVA for 2 factors and the fracture patterns were examined under an optical microscope at 65X magnification. Results: Thermal cycling did not influence the bond strength of the two sealants. The conventional sealant Climpro presented a statistically higher microtensile shear bond strength (11.72MPa, 11.34MPa with and without cycling, respectively) than the self-etching sealant Enamel Loc (5.92MPa, 5.02MPa with and without cycling, respectively). Fracture pattern analysis showed the occurrence of 100% of adhesive failures for Enamel Loc, while the conventional sealant Climpro presented 95% of adhesive failures and 5% of mixed failures. Conclusion: The conventional sealant presented higher microtensile shear bond strength to dental enamel in comparison with the self-etching sealant. Thermal cycling did not affect the bond strength of the sealants used in this study. © 2011 Nova Science Publishers, Inc.

The effects of exposure time on the surface microhardness of three dual-cured dental resin cements

This study evaluated the exposure time of light-curing of the polymers used for cementation on microhardness test in different storage times. The polymers (specifically called resin cements) were RelyX ARC, RelyX U100, and SET. Five specimens of each group were prepared and photo-polymerized with exposure times of 20 s and 180 s, using a LED polymerization unit with wavelength of 440 ~ 480 nm and light output was consistently 1,500 mW/cm2. The Vickers hardness test was performed in a MMT-3 Microhardness Tester. Data were submitted to ANOVA and Tukey's test (α = 0.05). The values of RelyX ARC showed statistically significant difference to groups with light exposure when considering only chemical cure (p < 0.05). The groups with light exposure (20 s and 180 s) showed no significant difference between them (p > 0.05). The RelyX U100 cured only chemically showed statistically significant difference between 48 h and 7 days (p < 0.05). The SET resin cement showed no significant difference to groups without light exposure for all storage times (p > 0.05). The values of hardening of the dual-cured resin cements improved after setting by light and chemical activation demonstrating the importance of light curing. © 2011 by the authors.

3D semantic models for dental education

This paper explores the benefits of using immersive and interactive virtual reality environments to teach Dentistry. We present a tool for educators to manipulate and edit virtual models. One of the main contributions is that multimedia information can be semantically associated with parts of the model, through an ontology, enriching the experience; for example, videos can be linked to each tooth demonstrating how to extract them. The use of semantic information gives a greater flexibility to the models, since filters can be applied to create temporary models that show subsets of the original data in a human friendly way. We also explain how the software was written to run in arbitrary multi-projection environments. © 2011 Springer-Verlag.

Influence of lateral excursion on vestibular cervical dental abfraction.

A study was performed to evaluate the influence of mandibular lateral excursion, group function and canine guidance on vestibular cervical dental abfraction (VCDA). Thirty-six individuals of both sexes, aged 20 to 45 years, with full natural dentition with at least one tooth with VCDA were selected at the San Marcos University Clinic. We evaluated number of teeth with VCDA per side (left and right), tooth type and lateral excursive movement (canine guidance or group function) affecting it. The results showed no statistical difference (p > 0.05). The tooth type most often showing VCDA was the first lower premolar, with 30.8% on the right side and 36.4% on the left. Moderate positive correlation was found between age and VCDA (R = 0.40). It is concluded that group function during lateral excursion may contribute to presence of VCDA.

Influence of dental exposure to oral environment on smear layer removal and collagen exhibition after using different conditioning agents

Although in vitro studies have shown encouraging results for root surface conditioning with demineralizing agents, in vivo studies have failed to show its benefits in periodontal healing. This can be attributed to several factors, among which, the hypermineralization of dental surface. Therefore, this in vitro study compared, using scanning electron microscopy (SEM), the effect of root surface conditioning with different conditioners (1% and 25% citric acid, 24% EDTA and 50 mg/mL tetracycline hydrochloride) in impacted teeth and in teeth that had their roots exposed to the oral environment. One trained examiner assessed the SEM micrographs using a root surface modification index. There was a tendency of more root surface modification in the group of impacted teeth, suggesting that the degree of root mineralization influences its chemical demineralization.

Evaluation of transverse changes in the dental arches according to growth pattern: a longitudinal study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dental age as indicator of adolescence

Aim: The purpose of the present study was to analyze the relationship between root formation of the first premolars and skeletal maturation stages identified in hand-wrist radiographs. Methods: A cross-sectional study was carried out involving the panoramic and hand-wrist radiographs obtained on the same date of 232 patients, 123 boys and 109 girls aged 4 years and 5 months to 17 years and 12 months. Root formation stages of the first premolars were related to the ossification stages of the sesamoid bone, epiphyseal stages of the phalanx of the thumb and epiphyseal stages of the radius. Results: The studied variables demonstrated statistically significant correlations. Conclusion: Roots of the lower first premolars do not reach 2/3 of their complete length before adolescence.

Discrepancies between abstracts presented at international association for dental research annual sessions from 2004 to 2005 and full-text publication

Purpose. The purpose of this study was to evaluate the discrepancies between abstracts presented at the IADR meeting (2004-2005) and their full-text publication. Material and Methods. Abstracts from the Prosthodontic Section of IADR meeting were obtained. The following information was collected: abstract title, number of authors, study design, statistical analysis, outcome, and funding source. PubMed was used to identify the full-text publication of the abstracts. The discrepancies between the abstract and the full-text publication were examined, categorized as major and minor discrepancies, and quantified. The data were collected and analyzed using descriptive analysis. Frequency and percentage of major and minor discrepancies were calculated. Results. A total of 109 (95.6%) articles showed changes from their abstracts. Seventy-four (65.0%) and 105 (92.0%) publications had at least one major and one minor discrepancies, respectively. Minor discrepancies were more prevalent (92.0%) than major discrepancies (65.0%). The most common minor discrepancy was observed in the title (80.7%), and most common major discrepancies were seen in results (48.2%). Conclusion. Minor discrepancies were more prevalent than major discrepancies. The data presented in this study may be useful to establish a more comprehensive structured abstract requirement for future meetings. © 2012 Soni Prasad et al.

Occurrence of traumatic dental injury in cases of domestic violence

The purpose of this study was to investigate the prevalence and types of traumatic dental injuries in situations of domestic violence. A coross-sectional study was conducted and data were collected from the police occurrence records to domestic physical aggression between 2001 and 2005. Of the 1,844 subjects who underwent medical evaluation, 15 had information pertaining to traumatic dental injuries. From the medical records, the forensic medical reports completed by the forensic medical experts who examined the victims after the aggression were reviewed and data of individuals with dental injuries (e.g., fractures, luxation and avulsion) were collected. In the selected sample, there was a predominance of individuals with injuries to the head and neck region (38.7%), and the frequency of traumatic dental injuries among all injuries to the head and neck region was 2.0%. The most frequently injured teeth were the maxillary incisors (31.8%), followed by the mandibular incisors (27.3%) and the maxillary canines (9.1%). In 31.8% of the injured teeth, the forensic experts did not specify the nomenclature. Of the dental trauma cases, 59.1% were fractures, 27.2% were luxations and 13.7% were avulsions. In conclusion, domestic violence was an important etiologic factor of traumatic dental injury. The aggression in all cases occurred in the form of punches and slaps. Fracture was the most common type of traumatic dental injury, and the most frequently injured teeth were the incisors.

Effect of brushing with conventional versus whitening dentifrices on surface roughness and biofilm formation of dental ceramics

The aim of this study was to evaluate the effect of conventional and whitening dentifrices on the weight loss, surface roughness, and early in situ biofilm formation on the surface of dental ceramics. Standardized feldspar ceramic specimens (Vita VM7 and Vita VM13) were submitted to the following experimental conditions: no brushing; brushing without a dentifrice; brushing with a conventional dentifrice; and brushing with a whitening dentifrice. A brushing machine was used to simulate brushing. The mass and surface roughness of all specimens from the test groups were evaluated prior to and after brushing. Ten participants used an oral device for eight hours to evaluate the biofilm formed in situ on the specimens. Scanning electron microscopy was used for qualitative and quantitative analysis of the biofilm. ANOVA and Tukey tests were used to analyze the results of weight loss, surface roughness, and presence of bacteria. A one-way Kruskal-Wallis test was used for bacterial colonization results. For both ceramics, brushing with a whitening dentifrice resulted in weight loss that was significantly greater when compared to brushing without a dentifrice or with a conventional dentifrice. Increased surface roughness was noticed on VM13 ceramic samples with both dentifrices, whereas only conventional dentifrice had a significant effect on the surface roughness of VM7 samples. For both VM7 and VM13, no difference was found between the experimental conditions with regard to the presence or number of bacteria. Cocci and short rods were the predominant microbial morphotypes. Granular or fibrillar acellular material partially covered the specimens. Brushing with a whitening dentifrice resulted in significant weight loss of ceramic restorations, while brushing with both conventional and whitening dentifrices can roughen ceramic surfaces. The increase in roughness was not clinically significant to contribute to increased biofilm formation.

Speech therapy intervention before dental management in patients with special needs: A case report

Fragile X syndrome is a cytogenetic abnormality related to chromosomal X. This syndrome is frequently associated to intellectual disability, psychological problems, as well as heart, skeletal and join alterations. Intraoral anomalies include malloclusion, ogival palate, cleft palate, presence of mesiodens, dental hypomineralization and abrasion of the occlusal surfaces and incisai edges. The study of characteristics of this syndrome is important for the dentist in order to guide dental treatment and prevention. The aim of this study is to present a myofunctional therapy protocol, evaluated by surface electromyography. A case of a 21 year-old young man who attended the Training Program in Dentistry for Persons with Disabilities, School of Dentistry of São José dos Campos/UNESP is reported. He underwent myofunctional therapy before dental treatment and the masticatory muscles were evaluated by surface electromyography. The exercises of myofunctional therapy consisted of active and passive simple movements of opening and closing the mouth, tongue protrusion and retrusion, digital manipulation and also by using an electric massager on intraoral and perioral region of the masseter, buccinator and orbicularis oris. Action potentials of the masticatory muscles decreased in almost all the muscles and values for the bite force and mandibular opening capacity increased. This study showed that brief and immediate myofunctional therapy optimized clinical practice with positive repercussion on dental care.

Influence of different disinfecting solutions on the color change of artificial irises used in ocular prostheses

Making an artificial iris with an aesthetically acceptable color is an important aspect of ocular rehabilitation. This work evaluated the influence of different disinfecting solutions on changes to the color of artificial irises used in ocular prostheses. Fifty samples simulating ocular prostheses were produced with cobalt blue artificial irises and divided (n = 10) according to the disinfectant used: neutral soap, Opti-free, Efferdent, 1% hypochlorite, and 4% chlorhexidine. The samples were disinfected for 120 days and subjected to a color readings by spectrophotometry, using the CIE L*a*b* system, before the disinfection period (B), after 60 days of disinfectant exposure (T 1), and after 120 days of disinfectant exposure (T 2). Color differences (ΔE) were calculated for the intervals between T 1 and B (T 1B), and between T 2 and B (T 2B). The data were evaluated by analysis of variance and the Tukey Honestly Significantly Different (α = 0.05). All disinfectant groups exhibited color changes. The mean color change observed for all groups overall during T 2B (ΔE = 3.51) was significantly greater than that observed during T 1B (ΔE = 2.10). All groups exhibited greater color change for the b* values when compared to the a* and L* values. There were no significant differences between the disinfectant groups. It can be concluded that the time period of disinfection and storage significantly affected the stability of artificial iris color, independent of the disinfectant used. © 2012 Wiley Periodicals, Inc.

Optical characterization of one dental composite resin using bovine enamel as reinforcing filler

The use of composite resins for restorative procedure in anterior and posterior cavities is highly common in Dentistry due to its mechanical and aesthetic properties that are compatible with the remaining dental structure. Thus, the aim of this study was to evaluate the optical characterization of one dental composite resin using bovine enamel as reinforcing filler. The same organic matrix of the commercially available resins was used for this experimental resin. The reinforcing filler was obtained after the gridding of bovine enamel fragments and a superficial treatment was performed to allow the adhesion of the filler particles with the organic matrix. Different optical images as fluorescence and reflectance were performed to compare the experimental composite with the human teeth. The present experimental resin shows similar optical properties compared with human teeth. © 2012 SPIE.