The Effect of Brushing on Surface Roughness of Denture Lining Materials

PURPOSE: The purpose of this study was to test the effect of brushing on surface roughness of two resilient liners (Luci Sof and Sofreliner) compared with an acrylic resin (QC 20). MATERIALS AND METHODS: Twenty specimens of each material were prepared (25 mm x 14 mm x 3 mm). Ten specimens served as controls and were stored in distilled water and not brushed. The remaining ten specimens were subjected to mechanical brushing, using an MSEt plus machine to simulate brushing at a rate of 5.0 strokes per second (30,000 cycles). Surface roughness measurements were recorded before and after brushing. Random samples were analyzed using scanning electron microscope. Data collected were analyzed by a two-way analysis of variance using material and treatment as variables, followed by Tukey's test (alpha= 0.05). RESULTS: Initial surface roughness of materials indicated that QC 20 was the smoothest (0.13 microm), and Luci Sof the roughest (0.68 mum). Sofreliner had an intermediate value (0.31 microm). All materials were significantly different. Mechanical brushing significantly increased surface roughness in all the materials. Although there was no statistical difference between QC 20 and Luci Sof after mechanical brushing (0.88 and 1.00 microm, respectively), both differed significantly from Sofreliner (7.74 microm). CONCLUSION: The two resilient liners and the acrylic resin became rougher, to a greater or lesser extent, when subjected to mechanical brushing.     

Dimensional alterations and solubility of new endodontic sealers

This study evaluated the dimensional alterations and the solubility of two experimental endodontic sealers based on Copaifera multijuga oil-resin (Biosealer) and castor oil bean cement (Poliquil), maintained in different storage solutions. Twenty specimens (3 mm diameter and 2 mm height) of each sealer were assigned to 2 groups (n=10) according to the storage solution: simulated tissue fluid (STF) or distilled water (DW). The specimens were stored in these solutions during 90 days, being removed every 30 days for weighting. The solutions were renewed every 15 days. The results were subjected to statistical analysis by Dunn's and Mann-Whitney tests (a=0.05). The solubility of Poliquil was higher in STF (38.4 ± 36.0) than in DW (28.4 ± 15.0), while Biosealer showed higher solubility in DW (34.61 ± 6.0) than in STF (18.59 ± 8.0). The storage solution influenced the behavior of sealers in relation to the weight variation (p=0.0001). Poliquil presented higher variation of weight independent of the solution (p=0.239). Biosealer also presented higher variation of weight regardless of the solution (p=0.0001). The solubility of Biosealer was different from that of Poliquil, but both sealers showed low solubility in STF. Under the tested conditions, neither of the materials were according to the ADA'S specification.     

Embolization of pseudoaneurysm of the internal maxillary artery after orthognathic surgery

In orthognathic surgery, Le Fort I osteotomy is one of the most often used methods for the correction of dental-facial deformities and is considered technically safe. However, this procedure may lead to diverse complications, including uncommon vascular complications. A clinical case is described of late development of pseudoaneurysm in one of the branches of the maxillary artery in a 20-year-old patient who had undergone Le Fort I osteotomy, bilateral sagittal osteotomy of mandibular branch, and mentoplasty and subsequently treated with embolization. The main forms of treating vascular injuries are reviewed, and embolization is demonstrated to be a technically safe procedure with few complications.     

Composite shrinkage stress as a function of specimen dimensions and compliance of the testing system.

OBJECTIVES: Verify the influence of specimen dimensions on composite shrinkage stress in testing systems of known compliance and in situations where axial strain of bonding substrates was suppressed. Stress distribution was evaluated using finite element analysis (FEA). METHODS: A chemically activated composite (Bisfill 2B, Bisco) was inserted between the flat surfaces of two glass rods (2, 4 or 6mm diameter, D) attached to a universal testing machine. Specimen height (H) was defined by adjusting the distance between the rods (0.5, 1, 2 or 4mm). An extensometer was used to monitor the distance between them. Maximum force after 30min of polymerization was divided by the cross-sectional area of the rod to obtain nominal stress (sigma(n)). Mathematical equations were employed in order to estimate the 'corrected nominal stress' (sigma(cor)) that would be obtained in ideally rigid systems. Data were analyzed by two-way ANOVA/Tukey test (alpha=0.05) and regression analysis (stress versus 'C factor' and stress versus specimen volume). Axysimetrical 2D models were used to evaluate X-component stress distribution (sigma(x)) in the zero compliance condition. RESULTS: The interactions between D and H were significant for sigma(n) and sigma(cor) (p<0.001). For D=2mm, height influenced only sigma(cor) values. A direct correlation was found between stress and C factor (sigma(n):R(2)=0.959; sigma(cor):R(2)=0.923), but not between stress and volume. FEA evidenced the effect of boundary restraints on sigma(x). SIGNIFICANCE: Specimen dimensions influenced test results, mostly regarding sigma(cor). Stress values strongly increased with the confinement of the specimen probably due to stress concentration adjacent to the bonded interface.     

Progressive dental development in regional odontodysplasia

Regional odontodysplasia (RO), also known as ghost teeth, is an unusual nonhereditary developmental anomaly of tooth formation that characteristically affects enamel and dentin formation of the primary and/or permanent dentition. In the present paper, we report a case of RO affecting a 7-year-old boy, with 9 years of follow-up. During this time, progressive development of dental tissue was observed, including complete root formation. However, delayed dental eruption was evident. In view of these findings, we discuss the clinical presentation, pathogenesis, differential diagnosis, and treatment of RO.     

PATTERN OF DISOCCLUSION IN PATIENTS WITH COMPLETE CLEFT LIP AND PALATE

Objective:

to analyze the pattern of disocclusion during excursive mandibular movements and presence or absence of occlusal interferences and occlusal pathologies (gingival recession and abfraction).

Method:

examination of 120 individuals divided into two groups, as follows: Group 1-90 patients with complete cleft lip and palate (study group), subdivided into 30 patients with complete left unilateral cleft lip and palate, 30 patients with complete right unilateral cleft lip and palate and 30 patients with complete bilateral cleft lip and palate; Group 2-30 individuals without clefts (control group).

Results:

58.8% of patients in Group 1 presented unilateral or bilateral canine guidance, 26.6% presented unilateral or bilateral group function and 54.4% presented lateral movements through the posterior teeth. Regarding protrusive movements, 80% presented anterior guidance and 20% presented posterior guidance. In Group 2, 69.6% of individuals presented unilateral or bilateral canine guidance, 43.2% presented unilateral or bilateral group function and only 13.3% presented lateral movements through the posterior teeth; 3.4% presented protrusion through the posterior teeth.

Conclusions:

there was no difference in the pattern of disocclusion between subgroups of patients with clefts. Group 2 presented predominance of bilateral group function, whereas Group 1 presented a higher prevalence of posterior guidance during lateral movements. Protrusion occurred primarily through anterior guidance in Group 2 and through the posterior teeth in Group 1. There was high prevalence of occlusal interferences at the molar area for both groups, yet with no correlation with occlusal pathologies (recession and abfraction).     

Critical-size defect ossification: effect of leporid age in a cranioplasty model

The ability of the human cranium to ossify full-thickness defects depends on the size of the area and the age of the patient. An adult leporid cranioplasty model is commonly used to study inlay cranioplasty materials; the influence of age on ossification is unknown in this model. The purpose of this study was to determine the effect of age on healing of a rabbit critical-size defect. Nineteen rabbits were divided into 4 groups: group 1 (n = 5) aged 4 months, group 2 (n = 4) aged 8 months, group 3 (n = 5) aged 12 months, and group 4 (n = 5) aged 16 months. A 17 × 17-mm defect was created in the parietal bones with preservation of the underlying dura. Animals underwent micro-computed tomography 4 months postoperatively to determine ossification of the defect. Group 1 defects healed by 28.5% (SD, 12.5%), group 2 defects ossified by 37.2% (SD, 5.7%), group 3 defects closed by 28.2% (SD, 11.9%), and group 4 defects healed by 39.4% (SD, 11.0%). No difference in ossification was found between groups (P = 0.31).Leporids as young as 4 months do not close a 17 × 17-mm defect; ossification is similar to animals as old as 16 months. Rabbits 4 months or older are suitable for a calvarial critical-size defect model.     

Edentulism, use of dentures and consumption of fruit and vegetables in south Brazilian community-dwelling elderly

There is evidence suggesting that edentulous older persons modify their diet, avoiding foods that are difficult to chew, such as fruit and vegetables; meanwhile, the consumption of these foods is associated with prevention of chronic diseases. However, few studies evaluated whether a poor oral status without prosthetic rehabilitation is associated with a reduction in the consumption of fruit and vegetables in community-dwelling older persons. We evaluated the association of oral status with emphasis on complete dentures use with the daily consumption of at least 400 g of fruit and vegetables, following the recommendations of the WHO. A random sample of 282 south Brazilians ≥60 years of age was evaluated. Measurements included a questionnaire to assess sociodemographic, behaviour, and health data; consume of fruit and vegetables by means of a 24-h diet recall, and oral status assessment, by means of oral examinations assessing the number of teeth and use of dental prosthesis. Multivariate Poisson regression showed that the only variable significantly associated with inadequate consumption of fruit and vegetables was edentulism with the use of only one denture [PR=1·75 (1·11-2·74)]. Edentulous participants wearing only one denture were less likely to consume at least 400 g day(-1) of fruit and vegetables. These results indicate that, in edentulous community-dwelling elderly, oral health rehabilitation might play an important role in the maintenance of consumption of adequate amounts of fruit and vegetables, which is an important component of a healthy diet and also in the prevention of chronic diseases.     

Lip cavernous hemangioma in a young child

Hemangiomas are benign tumors of infancy and childhood, characterized by a phase of fast growth with endothelial cell proliferation, occurring in 10-12% of children at 1 year of age. It is known that hemangiomas of infancy are most commonly located on the head and neck region (around 60% of cases) and occur more frequently in the lips, tongue, and palate. Approximately 50% of hemangiomas have complete resolution, and 90% of them are resolved up to the age of 9. Complications occur in only 20% of the cases, the most common problem being ulceration with or without infection. The treatment depends on lesion location, size and evolution stage, and the patient's age. Surgery is usually indicated when there is no response to systemic treatments, or even for esthetic reasons, being performed as a simple excision in combination or not with plastic surgery. This paper reports a case of lip cavernous hemangioma in a 4-year-old child, who was submitted to 3 sessions of vascular sclerosis due to the size of the lesion, before undergoing simple excision of the hemangioma. Two years of postoperative clinical follow-up shows treatment success with no recurrence of the lesion.