Objectives Evaluate the thickness and the marking quality of different occlusal contact registration strips (OCRS) and a possible correlation between them. Material and Methods The following OCRS were selected: Accufilm II, BK20, BK21, BK22, BK23, BK28, and BK31. The thickness was measured in three points of the OCRS with an electronic measuring device (TESA), and the mean was calculated. To produce the marks on the strips, composite resin specimens were adapted to a universal testing machine (Versat 2000) with 40 kgf load cell at a speed of 1.0 mm/min. The mark images were photographed with a stereoscopic microscope (Stemi SV11) and processed and analyzed by the 550-Leica Qwin® analyzer. Results Values (μm) found in the 1st and 2nd thickness measurements were: Accufilm II - 16.4 and 14.2; BK20 - 10.0 and 8.1; BK21 - 9.5 and 8.0; BK22 - 9.7 and 8.7; BK23 - 9.8 and 7.9; BK28 - 12.8 and 10.0; and BK31 - 8.4 and 8.0, respectively. The mean (mm2) values found in the mark areas were: Accufilm II - 0.078; BK20 - 0.035; BK21 - 0.045; BK22 - 0.012; BK23 - 0.022; BK28 - 0.024; and BK31 - 0.024. The results were submitted to the Kruskal-Wallis (p<0.05) and Pearson’s correlation tests. Conclusions Only in the 2nd measurement, the OCRS thickness observed was similar to the value indicated by the manufacturers; the Accufilm II and the BK28 strips showed the better marks; and no correlation was found between the thickness and the marking area.
OBJECTIVE: To compare dental and skeletal anchorages in mandibular canine retraction by means of a stress distribution analysis. METHODS: A photoelastic model was produced from second molar to canine, without the first premolar, and mandibular canine retraction was simulated by a rubber band tied to two types of anchorage: dental anchorage, in the first molar attached to adjacent teeth, and skeletal anchorage with a hook simulating the mini-implant. The forces were applied 10 times and observed in a circular polariscope. The stresses located in the mandibular canine were recorded in 7 regions. The Mann-Whitney test was employed to compare the stress in each region and between both anchorage systems. The stresses in the mandibular canine periradicular regions were compared by the Kruskal-Wallis test. RESULTS: Stresses were similar in the cervical region and the middle third. In the apical third, the stresses associated with skeletal anchorage were higher than the stresses associated with dental anchorage. The results of the Kruskal-Wallis test showed that the highest stresses were identified in the cervical-distal, apical-distal, and apex regions with the use of dental anchorage, and in the apical-distal, apical-mesial, cervical-distal, and apex regions with the use of skeletal anchorage. CONCLUSIONS: The use of skeletal anchorage in canine retraction caused greater stress in the apical third than the use of dental anchorage, which indicates an intrusive component resulting from the direction of the force due to the position of the mini-implant and the bracket hook of the canine.
OBJETIVO: comparar as ancoragens dentária e esquelética na retração do canino inferior, por meio do estudo da distribuição de tensões. MÉTODOS: foi confeccionado um modelo fotoelástico de segundo molar a canino, sem o primeiro pré-molar, e simulada a retração do canino inferior com elástico preso a dois tipos de ancoragem: dentária, no primeiro molar conjugado aos dentes adjacentes; e ancoragem esquelética, em gancho simulando o mini-implante. As forças foram aplicadas 10 vezes e observadas no polariscópio circular. As tensões no canino inferior foram registradas em 7 regiões. O teste de Mann-Whitney foi aplicado para comparar as tensões em cada região, considerando os dois sistemas de ancoragem. As tensões nas regiões perirradiculares do canino foram comparadas pelo teste de Kruskal-Wallis. RESULTADOS: as tensões foram similares tanto na região cervical quanto no terço médio. No terço apical, as tensões associadas à ancoragem esquelética foram maiores que as tensões associadas à ancoragem dentária. Os resultados do teste de Kruskal-Wallis mostraram que as maiores tensões foram identificadas nas regiões cervicodistal, apicodistal e na região do ápice com o uso da ancoragem dentária; e com o uso da ancoragem esquelética, as maiores tensões se localizaram nas regiões apicodistal, apicomesial, cervicodistal e no ápice. CONCLUSÃO: o uso de ancoragem esquelética na retração promoveu maior tensão no terço apical do que o uso da ancoragem dentária, indicando um componente intrusivo devido à direção da força decorrente da posição do mini-implante e do gancho do braquete do canino.
The purpose of this study was to evaluate the dimensional accuracy of different materials used in the confection of dies. Two stainless steel standard models were confected. One of the models, which was 2 mm larger than the other model, was used to provide a uniform relief for the two-step putty-wash impression technique. Thirty impressions were obtained using a polyvinyl siloxane impression material and randomly divided into three groups (n = 10) according to the type of casting material: type IV dental stone, commercially available epoxy resin (Tri-Epoxy), and industrial epoxy resin (Sikadur). After the setting/polymerization of the casting material, the dimensional stability was measured in terms of the height, diameter of the base and diameter of the top from the obtained dies and from the standard metal model using a profile projector. Results were analyzed by ANOVA and Dunnet test (α = 0.05). In the height values, no significant difference was observed between the groups, except for Sikadur casts, which showed lower mean values. The Tri-Epoxi group showed statistically lower mean base diameter values, compared with the other groups, and both epoxy resin groups showed statistically lower mean top diameter values, compared with that for the type IV dental stone group. We concluded that type IV gypsum and the commercially available epoxy resin showed similar behavior in most areas. The industrial epoxy resin did not show the same characteristics, although the diameter of the base obtained with it was similar to that obtained with type IV dental stone.
The aim of this study was to evaluate the accuracy of three implant transfer impression techniques. Four groups (n = 5) were defined, according to the technique: TC - tapered copings without splint; SC - square copings without splint; SCS - square copings splinted with dental floss and acrylic resin, and CG (control group) - master model with four external hexagonal implants and a superstructure. Individual trays and polyether were used for the impression. All casts were checked for their fit into the master superstructure; for this, all four screws were placed in the implants. Digital photos were taken and images were analyzed using UTHSCSA ImageTool software. Statistical analyses were performed using one-way analysis of variance and Studentâ€™s t test (p < 0.05). The means and standard deviation were (µm): CG = 2.03 ± 0.00, TC = 14.74 ± 3.41, SC = 12.08 ± 2.56, and SCS = 6.51 ± 0.09. The control group was found to be statistically different from the TC and SC groups. Within the limitations of this study, all groups presented clinically acceptable standard gap values, and the SCS group showed no statistical difference in relation to the CG (control group), demonstrating more accuracy and fidelity to transfer implants.
During clinical practice, when performing prosthetic rehabilitation with single crowns, improper reproduction of the dental contour by the dental laboratory is a common occurrence. Therefore, the present study evaluated the fidelity of the reproduction of the buccal contour in an upper left canine performed by three Dental Prosthesis Technicians (DPT) using the indirect laminate veneer technique. First, the DPTs confected the veneers based on a model obtained from the upper arch of a dental dummy, containing a replica of an upper left canine with a prosthetic preparation for a laminate veneer. Then, the same DPTs received other identical models, now with the replica of the upper left canine with no preparation, to be used as an anatomical reference for confecting the laminate veneers. The laminate veneers were then bonded to the plaster models and had their buccal contour individually measured. Measurements were also made of the buccal contour of the reference canine. The data were analyzed by ANOVA and the t-test (p = 0.05). Results showed 100% of buccal overcontour when the laminate veneers were compared to the reference canine, regardless of which DPT confected the veneer and regardless of using or not the anatomical reference. The DPTs who participated in the present study were unable to acomplish a faithful anatomical reproduction of the buccal contour, creating an overcontour in all samples. This situation may be responsible for increasing the probability of periodontal and esthetic harm in clinical practice.
The use of denture is known to increase the carriage of Candida in healthy patients, and the proliferation of Candida albicans strains can be associated with denture-induced stomatitis. The aim of this study was to evaluate the use of vinegar as an antimicrobial agent for control of Candida spp. in complete upper denture wearers. Fifty-five patients were submitted to a detailed clinical interview and oral clinical examination, and were instructed to keep their dentures immersed in a 10% vinegar solution (pH less than 3) overnight for 45 days. Before and after the experimental period, saliva samples were collected for detection of Candida, counting of cfu/mL and identification of species by phenotypical tests (germ tube formation, chlamidoconidia production, and carbohydrate fermentation and assimilation). The results were analyzed using Spearman's correlation and Student's t-test (p£0.05). Candida yeasts were present in 87.3% of saliva samples before the treatment. A significant reduction was verified in CFU/mL counts of Candida after treatment. A positive correlation between Candida and denture stomatitis was verified, since the decrease of cfu/mL counts was correlated with a reduction in cases of denture stomatitis. Although it was not able to eliminate C. albicans, the immersion of the complete denture in 10% vinegar solution, during the night, reduced the amounts (cfu/mL) of Candida spp. in the saliva and the presence of denture stomatitis in the studied patients.
The aim of this study was to evaluate the effect of different curing methods on the stress generated by the polymerization shrinkage of a restorative composite in two moments: immediately after light exposure and after 5 min. Photoactivation was performed using two different light sources: (1) xenon plasma arc (PAC) light (1,500 mW/cm2 - 3s) and (2) a quartz-tungsten-halogen (QTH) light with three light-curing regimens: continuous exposure (40 s at 800 mW/cm2 - CL); soft-start (10 s at 150 mW/cm2 and 30 s at 800 mW/cm2 - SS) and intermittent light [cycles of 4 s (2 s with light on at 600 mW/cm2 and 2 s of light off), for 80s - IL]. The composite resin was applied between two 5-mm diameter metallic rods, mounted in a servohydraulic machine. The maximum stress was recorded immediately after light exposure (FF) and after 5 min (5F). The results were submitted to ANOVA and Tukey's test (5%). For each method, the results obtained in FF and 5F were, respectively: CL (3.58 and 4.46 MPa); SS (2.99 and 4.36 MPa); IL (3.11 and 4.32 MPa) and PAC (0.72 and 3.27 MPa). The stress generated by the polymerization shrinkage during light exposure can be associated with the photoactivation method used. A significant increase in the stress level was observed during the post-curing period up to 5 min, for all evaluated methods.
This survey investigated the etiology of atrophy or loss of the ocular globe in patients assisted at the Maxillofacial Prosthetics Clinic of two Schools of Dentistry in São Paulo State, Brazil. A total of 238 patients were examined and their clinical files were reviewed. The etiology of eyeball atrophy/loss was assessed with respect to gender, age group, affected side and type ophthalmologic surgery performed. The greatest incidence of ocular globe loss was due to traumatic etiology (57.14%), followed by pathogenic (36.13%) and congenital (5.04%) etiologies. Comparing the genders, a predominance of male patients was observed (61.76%; p<0.01). The age group most frequently affected was between 21 and 40 years (42.01%; p<0.01). For all types of etiologies investigated in this study, enucleation was the most commonly used surgical procedure for removal of the ocular globe (66.38%; p<0.01). Loss of the left eye was predominantly seen (55.04%), even though no statistically significant difference was found between sides (p>0.01).
Este estudo investigou a etiologia dos casos de atrofia e perda do globo ocular em pacientes atendidos no ambulatório de prótese buco-maxilo-facial de duas Faculdades de Odontologia do estado de São Paulo. Um total de 238 pacientes e seus prontuários foram examinados, e a etiologia e incidência dos casos de atrofia e perda do globo ocular foram avaliados considerando gênero, faixa etária, lado afetado e tipo de cirurgia oftalmológica realizada. As perdas por etiologia traumática foram as de maior incidência (57,14%), seguidas das perdas por etiologia patogênica (36,13%) e com menor incidência para as perdas por causas congênitas (5,04%). Comparando-se os gêneros, houve predominância da população masculina (61.76%; p<0,01). A faixa etária mais freqüentemente atingida foi a de 21 a 40 anos (42.01%; p<0,01). Em todas as etiologias estudadas, a cirurgia mais empregada para remoção do globo ocular foi a enucleação (66.38%; p<0,01). Houve predominância da perda do globo ocular do lado esquerdo (55.04%), mas não houve diferença estatisticamente significante.
The author developed a scale in silicone of shades of human skin. Twenty-seven samples were produced in acetic silicone (Silastic 732 RTV), pigmented with iron oxides and titanium dioxide. The amount of acetic silicone was kept constant (two grams) in all of the samples, and the pigments were mixed to it in varying proportions, until twenty-seven different shades were obtained. By comparing the color of the samples with the skin color of forty-one individuals, five samples were selected of the shades that best matched a patient's color of skin to form a shade guide. With the methodology employed, it was possible to develop a shade guide that will facilitate a definition of a patient's skin color in producing facial prostheses in silicone, to afford economy in time and in material at time for selecting the color.
O autor desenvolveu em silicona uma escala de tonalidades de pele humana. Foram confeccionados vinte e sete corpos-de-prova em silicona acética (Silastic 732 RTV), pigmentados com óxidos de ferro e dióxido de titânio. A quantidade de silicona acética manteve-se constante (dois gramas) em todos os corpos-de-prova, e os pigmentos foram misturados a ela em várias proporções até a obtenção de vinte e sete diferentes tonalidades. Através da comparação da cor dos corpos-de-prova com a cor da pele de quarenta e um indivíduos, foram selecionados os cinco corpos-de-prova com as tonalidades que mais se igualavam à cor da pele dos pacientes, compondo, assim, um guia de tonalidades. Com a metodologia empregada, foi possível desenvolver uma escala de tonalidades de pele que poderá facilitar a definição do tom da pele do paciente quando da confecção de próteses faciais em silicona, permitindo economia de tempo e de material no momento da seleção da cor.