RCAAP Repository

The purpose of this report is to present educational material that would allow the dental student to learn to easily identify the morphologic characteristics of permanent teeth, and how they fit together (occlusion). In order to do this, macro models of permanent teeth with no attrition were carved in wax and later molded with alginate. These molds were filled with plaster, dental stone and/or cold-cured acrylic resin. The large individual dental stone tooth models were mounted on a wax base, thus obtaining maxillary and mandibular arches which were occluded. These dental arches were molded with plaster or dental stone. The authors suggest that these types of macro models allow an excellent visualization of the morphologic characteristics of permanent teeth and occlusion. Dental students are able to carve the permanent dentition in wax with great facility when they can observe macro models.

Review of the literature from 1991 to 2002 on the use of rapid prototyping in the biomedical area emphasizes the applicability of this technique to aid diagnosis and planning in Maxillofacial Surgery and Traumatology. A case report in which a TMJ ankylosis relapse was treated using rapid prototyping (selective laser sintering) for surgery planning is presented. After one year, the patient's buccal opening was 45 mm. Transitory paralysis of the facial nerve disappeared totally in six months.

Fungal infections are on the increase and those of the jaw cavities with Aspergillus species may be connected with the root apices of teeth in the upper jaw. Diagnostic changes in the sinus maxillaris and certain types of facial pain may be indicative of fungal infection. The authors report a case of aspergillosis sinusitis and describe the diagnostic methods and treatment of this infection that may be associated with endodontic treatment.

This in vivo study evaluated, through the physicochemical assay method for quantification of enhanced vascular permeability, the irritating potential of EDTA, EGTA, citric acid and saline. Thirty-two male Wister rats were anesthetized and four experimental sites were demarcated on their backs. Injections of 2% Evans blue (20 mg/kg) were administered intravenously into the lateral caudal vein. The test solutions were immediately injected intradermally (0.01 mL) into the experimental sites. The animals were killed 30 min, 1, 3 and 6 h after injection of the solutions and each piece of skin was submerged in formamide and incubated at 45ºC for 72 h. After filtration, the optical density was measured in a spectrophotometer and the total amount of dye extracted from the samples was calculated by means of a standard calibration curve. Data were analyzed statistically by two-way ANOVA and Tukey's HSD test. Compared to control, EDTA had the greatest volume of dye followed by EGTA and citric acid, for all time periods. There were statistically significant differences between all solutions (p<0.01). Considering the periods assessed, a significant difference was observed between the 3- and 6-h groups (p<0.05), but not between the 30-min and 1-h groups. Among the organic acids evaluated in this study, citric acid yielded the lowest amount of extracted dye. This indicates that the citric acid was the least irritating solution.

The purpose of this study was to investigate the periapical healing process of dogs' teeth with or without apical patency and after root canal filling with two types of sealers. Forty roots of premolars and incisors were utilized. The root canals were overinstrumented and dressed with a corticosteroid-antibiotic solution for 7 days to obtain ingrowth of periapical connective tissue into the canals. After this period, the tissue was removed in half of the specimens (groups with patency) and preserved in the other half (groups without patency). Canals were filled by lateral condensation technique with gutta-percha points and either a calcium hydroxide-based sealer (Sealer Plus) or a Grossman's cement (Fill Canal). The animals were killed by anesthetic overdose 60 days after the endodontic treatment and anatomic pieces were obtained and prepared for histologic examination. Data were evaluated in a blind analysis on the basis of several histomorphologic parameters. The groups without patency had better results (p=0.01) than those in which the ingrown connective tissue was removed. Comparing the sealers, Sealer Plus had significantly better results (p=0.01) than Fill Canal. In conclusion, both the apical patency (presence or absence) and the type of root canal filling material influenced the periapical healing process in dogs' teeth with vital pulp after root canal treatment. The use of a calcium hydroxide-based sealer in teeth without apical patency yielded the best results among the experimental conditions proposed.

This study evaluated microscopically the effects of root surface treatment with three different solutions in delayed rat teeth replantation. Central incisors from 30 rats (Rattus norvegicus, albinus Wistar) were extracted and left on a bench for 6 h. The pulps were extirpated and root canals were irrigated with 1% sodium hypochlorite. After endodontic treatment, the root surfaces of all teeth were submitted to a 10-min treatment with 1% sodium hypochlorite, changed every 5 min. The teeth were then rinsed with saline for 10 min and assigned to 3 groups with ten specimens each. Groups I, II and III were treated, respectively, with 2% acidulated-phosphate sodium fluoride, vitamin C solution and effervescent vitamin C (2 g, Redoxon®). After root surface treatment, the teeth were filled with calcium hydroxide and replanted. The animals were sacrificed after 10 and 60 days. Group I (fluoride) presented the largest areas of replacement resorption and ankylosis. Comparing both vitamin C groups, Group III (effervescent vitamin C) yielded better results, showing more areas of ankylosis and replacement resorption than areas of inflammatory resorption.

In the present study, periapical radiographs were analyzed to investigate the number of canals of the buccal root of maxillary 1st premolars with longitudinal sulcus, and compare the number of apical foramina observed on the radiographs to that revealed by scanning electron microscopy (SEM). Thirty-nine human maxillary 1st premolars had their crowns and palatal roots removed and the root canals (C) were explored with endodontic files until the tip of the instrument was visualized exiting the apical foramen/foramina (AF). Radiographs were taken with files inside the root canals and the specimens were classified as follows: 1C/1AF; 2C/2AF; 1C/2AF; 2C/1AF. Apices were examined under SEM and the number of apical foramina (considering those measuring >80 µm in diameter) was recorded. Only 17.1% (n=6) of the specimens had 1C/1AF; 77.2% (n=27) had 2AF in which 42.9% (n=15) had 2C and 34.3% (n=12) had 1C; 5.7% (n=2) had 2C/1AF. SEM examinations showed that 46.1% (n=18) of the specimens had 2AF; 23.1% (n=9) had 1AF; 23.1% (n=9) had 3AF; 7.7% (n=3) had 4AF. Radiographic and SEM findings for the number of AF coincided in 62.8% of the cases. A buccal longitudinal sulcus in the maxillary 1st premolar is usually accompanied by total bifurcation (42.9%) or apical bifurcation (34.3%) of the root canal. SEM identified a statistically higher number of apical foramina than radiographs (p<0.01).

The purpose of this study was to investigate the influence of cervical preflaring on the determination of the first file that binds at working length (WL) in buccal roots of maxillary premolars. Five groups (n=10) were formed at random and, after standard access cavities, the WL was determined 1 mm short from the apex. In group 1, the initial apical file was inserted without preflaring of cervical and middle thirds of the root canals. In groups 2 to 5, the cervical and middle thirds were enlarged with sizes 90 and 110 Gates-Glidden drills, K³ Orifice Opener instruments, ProTaper instruments and LA Axxess burs, respectively. Canals were sized manually with K-files, starting with #08 K-files inserted passively up to the WL. File sizes were increased until a binding sensation was felt at the WL and the size of the instrument was recorded. Transversal sections of the WL regions were examined under scanning electron microscopy and the discrepancies between the canal diameter and first file to bind at the WL were assessed. Significant differences (p<0.001) were found between the groups. The major discrepancy was found without preflaring (mean 157.8 µm). LA Axxess burs produced the smallest discrepancy (mean 0.8 µm). Gates-Glidden drills and K³ Orifice Opener instruments showed no significant differences (p>0.05) between their results (83.2 µm and 73.6 µm, respectively). The discrepancy for ProTaper instruments was 35.4 µm on average. In conclusion, the instrument binding technique for determination of the anatomical diameter at the WL was not precise. Preflaring of the cervical and middle thirds improved the determination of the anatomical diameter at the WL, and the type of instrument played a major role. Canals preflared with LA Axxess burs showed a more accurate binding of the files to anatomical diameter.

This in vitro study assessed the marginal microleakage on class V cavities prepared with aluminum oxide air abrasion and restored with different glass ionomer cements. The cavities were prepared on the buccal and lingual surfaces of 15 sound third molars with an air- abrasion device (Kreativ Mach 4.1; New Image) using a 27.5-µm aluminum oxide particle stream, and were assigned to 3 groups of 10 cavities each. The restorative materials were: group I, a conventional glass ionomer cement (Ketac-Fil); groups II and III, resin-modified glass ionomer cements (Vitremer R and Fuji II LC, respectively). After placement of the restorations, the teeth were stored in distilled water at 37ºC for 24 h, polished and then submitted to a thermocycling regimen of 500 cycles, isolated, immersed in 0.2% Rhodamine B solution for 24 h, included and serially sectioned. Microleakage was assessed by viewing the specimens under an optical microscope connected to a color video camera and a computer. The images obtained were digitized and analyzed for microleakage using software that allows for a standard quantitative assessment of dye penetration in millimeters. Statistical analysis was done using the Kruskall-Wallis and Wilcoxon tests. Means of dye penetration (%) were: occlusal - I: 25.76 ± 34.35, II: 20.00 ± 42.16, III: 28.25 ± 41.67; cervical - I: 23.72 ± 41.84; II: 44.22 ± 49.69, III: 39.27 ± 50.74. No statistically significant differences (p>0.05) were observed among either the glass ionomer cements or the margins. In conclusion, class V cavities restored with either conventional or resin-modified glass ionomer cements after preparation with aluminum oxide air abrasion did not show complete sealing at the enamel and dentin/cementum margins.

This study examined the average surface roughness (Ra, µm) of 2 microfilled (Durafill and Perfection), 1 hybrid (Filtek Z250) and 2 packable composite resins (Surefil and Fill Magic), before (baseline) and after eight different finishing and polishing treatments. The surface roughness was assessed using a profilometer. Ten specimens of each composite resin were randomly subjected to one of the following finishing/polishing techniques: A - carbide burs; B - fine/extrafine diamond burs; C - Sof-Lex aluminum oxide discs; D - Super-Snap aluminum oxide discs; E - rubber polishing points + fine/extrafine polishing pastes; F - diamond burs + rubber polishing points + fine/extrafine polishing pastes; G - diamond burs + Sof-Lex system; H - diamond burs + Super-Snap system. Data were analyzed using two-way ANOVA and Tukey's HSD test. Significant differences (p<0.05) were detected among both the resins and the finishing/polishing techniques. For all resins, the use of diamond burs resulted in the greatest surface roughness (Ra: 0.69 to 1.44 µm). The lowest Ra means were obtained for the specimens treated with Sof-Lex discs (Ra: 0.11 to 0.25 µm). The Ra values of Durafill were lower than those of Perfection and Filtek Z250, and these in turn had lower Ra than the packable composite resins. Overall, the smoothest surfaces were obtained with the use the complete sequence of Sof-Lex discs. In areas that could not be reached by the aluminum oxide discs, the carbide burs and the association between rubber points and polishing pastes produced satisfactory surface smoothness for the packable and hybrid composite resins, respectively.

The use of natural teeth for performing in vivo , in situ and/or in vitro studies has been widely observed in the dental field. The mechanical behavior of teeth subjected to masticatory efforts is commonly used as a variable of response. In conditions of malocclusion, the most relevant component accounting for the integrity of the dental structure is non-axial (flexural). This force, while acting on a tooth in function in the oral cavity, generates a similar situation as that of a beam in balance supporting a load concentrated on its free extremity. Based on this configuration, a methodology has been developed to investigate the behavior of teeth subjected to this kind of efforts, taking into consideration specific aspects of the tested teeth, such as the transversal section area and the moment of inertia. For determination of the transversal section area an image analysis program was used. For assessment of the other variables, a C++ language program was implemented utilizing the Borland Compiler C++ Builder, version 1.0, for Windows (Borland International, USA). The applicability of the developed methodology is illustrated in this article using bovine teeth. Our findings indicate that more accurate data can be obtained with the application of this methodology and that it is suitable for studies testing the flexural strength of extracted teeth, as a variable of response.

The purpose of this study was to compare the castability of Co-Cr-Mo-W (Remanium 2000), Ni-Cr (Durabond) and Co-Cr-Mo (Vera PDI) alloys invested with either conventional (phosphate- and silica-based) or mixed investing techniques. A 10 X 10 mm square-shaped nylon net containing 100 open squares served as a template for construction of wax patterns, which were invested with phosphate-based investment (Termocast), silica-based investment (Refrafil) and mixed investing technique (2-mm layer phosphate investment plus filling with silica investment). Forty-five cast specimens (5 per experimental condition) were obtained and sandblasted with aluminum oxide. The number of completely reproduced cast segments was counted to obtain a percentage designated "castability value", which indicated the accuracy of the alloy to reproduce mold details. Statistical analysis using two-way ANOVA and Tukey's test showed that, comparing the alloys, Remanium 2000 had statistically similar castability (p>0.05) to Vera PDI and lower than Durabond (p<0.05). Considering the mixed technique results, Remanium 2000 yielded lower castability value (p<0.05) than Durabond and Vera PDI alloys, which showed similar results to each other (p>0.05). In conclusion, the castability of the Co-Cr-Mo-W alloy (Remanium 2000) was comparable to that of the Co-Cr alloy (Vera PDI) and worse than that of the Ni-Cr alloy (Durabond). Except for Remanium 2000, the mixed investing technique considerably improved the accuracy of the alloys to reproduce cast details, compared to the phosphate-based investment. The mixed investing technique appears as a viable alternative to improve castability of base metal alloys without decreasing the surface quality of the metallic pieces.

In this study, proliferating cell nuclear antigen (PCNA) and p53 protein expressions were analyzed in 16 cases of ameloblastoma and 8 cases of adenomatoid odontogenic tumor (AOT). The cases of ameloblastoma consisted of solid type tumors and histologic arrangements of different subtypes were observed. In some specimens, more than one histologic subtype was identified in the same lesion, and each tumor was categorized according to the predominant cell pattern. The odontogenic tumors were grouped as follows: follicular ameloblastoma (n=7), plexiform ameloblastoma (n=4), acanthomatous + follicular ameloblastoma (n=3), basal cell ameloblastoma (n=2), adenomatoid odontogenic tumor (n=8). PCNA immunohistochemical expression revealed stronger quantitative labeling index for the follicular ameloblastoma, while for p53 protein the strongest quantitative labeling index was detected in the plexiform type. Nevertheless, statistical analysis using ANOVA and Tukey's test did not detect significant differences (p>0.05) among the histologic subtypes of ameloblastoma. The findings of this study suggest that the different histologic patterns of ameloblastoma did not show a direct correlation with their clinical behavior and consequently with the prognosis of the cases. The results also indicated that the ameloblastoma has greater proliferative potential than the AOT, which can contribute to explain its more aggressive and invasive characteristics.

The purpose of this study was to investigate the effects of cigarette smoke on the development of the embryo mandible (Meckel's) cartilage in rat fetuses. When inhaled by female Wistar rats between the 9th and the 12th day of pregnancy, cigarette smoke (5 cigarettes a day) caused intrauterine growth retardation, providing smaller fetuses and placentas. In fetuses from the experimental group, the histopathologic examination revealed a poorly developed Meckel's cartilage with smaller chondroblasts showing a scanty cytoplasm with spherical and paler central nuclei, as well as more abundant cartilage matrix. Morphometric analysis revealed that Meckel's cartilage lacunae were smaller in the fetuses from the experimental group, although not showing any remarkable alteration in shape. The results suggested that inhalation of cigarette smoke by pregnant rats during the organogenic period induced growth retardation and delayed cellular differentiation in rat fetal Meckel's cartilage.

The purpose of this study was the histomorphologic analysis of the efficacy of bioactive glass particles with a narrow size range (Biogran) in the periodontal healing of 2-wall intrabony defects in monkeys. The 2-wall defects were made in the mesial area of the left and right second premolars of four monkeys, filled with gutta-percha and, after 15 days, they were debrided and either naturally filled with coagulum (control) or implanted with bioactive glass (test). In the control sites, the junctional epithelium migrated up to the base of the defect. The presence of newly formed cementum was more significant in the test defects. Both control and test sites showed newly formed bone at the base of the defect. The test defects presented foci of newly formed bone around and within the glass particles localized in the middle third, distant from the defect walls. Histologic analysis showed that the 300- to 355-µm bioactive glass particles aided new periodontal insertion. In conclusion, the tested bioactive glass had better healing potential than debridement only. The graft material showed a promising inhibition of apical migration of the junctional epithelium and greater cementum deposition on the radicular surface of the intrabony defects. The replacement of bioactive glass particles by new bone occurred due not only to an osteoconductive property, but also to an osteostimulatory capacity. Future investigations should evaluate this potential comparatively or together with other grafting materials, regenerative techniques and biological modifiers, as well as assess the longitudinal stability of the new attachment.

This study compared in vivo the performances of commercially pure titanium (cp Ti) screw dental implants either uncoated or coated with synthetic hydroxyapatite (HA) by electrophoresis. The HA coating was characterized by scanning electron microscopy, energy dispersive spectroscopy (EDS) and Fourier-transform infrared (FT-IR) spectroscopy. Well-adhered carbonated-hydroxyapatite layers (4- to-8-µm-thick) were obtained. In vivo tests were carried out by insertion of both uncoated and HA-coated implants into rabbit tibiae for 8 or 12 weeks. Histomorphometric analysis was performed by scanning electron microscopy with the aid of image-processing software. Results showed significantly greater bone-implant contact for HA-coated implants (p<0.05) than cp Ti implants. Comparison of bone content inside the screw implants showed no significant differences (p>0.05) between both types of implants, although cp Ti had numerically higher percentage of bone content than HA-coated implants. In conclusion, the HA-coated implants had better performance regarding the bone-implant contact area than the uncoated implants; coating by electrophoresis proved to be a valuable process to coat metallic implants with an osteoconductive material such as hydroxyapatite.

One of the most important indications for guided tissue regeneration (GTR) treatment is class II furcation lesion. However, periodontal regeneration of this type of defect, although possible, is not considered totally predictable, especially in terms of complete bone fill. Many factors may account for variability in the response to regenerative therapy in class II furcation. The purpose of this review is to assess the prognostic significance of factors related to the patient (smoking, stress, diabetes mellitus, acquired immunodeficiency syndrome and other acute and debilitating diseases, and the presence of multiple deep periodontal pockets), local factors (furcal anatomy, defect morphology, thickness of gingival tissue and tooth mobility), surgical treatment (infection control, bone replacement grafts combined with barriers or GTR alone, type of barrier and surgical technique), and postoperative period (plaque control, membrane exposure, membrane retrieval and a regular supportive periodontal care program) for successful of GTR in class II furcations.

The purpose of this study was to evaluate the microhardness of resin-based materials polymerized with a LED (light-emitting diode) light-curing unit (LCU) and a halogen LCU. Twenty cylindrical specimens (3.0 mm in diameter and 2.0 mm high) were prepared for each tested material (Z100, Definite and Dyract). Specimens were light-cured with two LCUs (Ultraled and Curing Light 2500) for either 40 or 60 s on their top surfaces. Hardness was measured on top and bottom surfaces of each specimen. Statistical analysis was done by ANOVA and Tukey's test (p<0.05). There was no significant difference in hardness between LED LCU and halogen LCU for Z100 and Dyract on top surface. Conversely, lower hardness was recorded when Definite was light-cured with the LED LCU than with the halogen lamp. On bottom surface, hardness was significantly lower for all materials light-cured with LED LCU. Z100 was harder than Dyract and Definite regardless of the light curing unit. There was no significant difference in hardness between the exposure times on top surface. Higher hardness was obtained when the materials were light-cured for 60 s on bottom surface. The tested LED was not able to produce the same microhardness of resin-based materials as the halogen LCU.

This in vitro study evaluated the surface microhardness of human enamel submitted to bleaching with 10% carbamide peroxide (CP) containing calcium or fluoride. Ninety-eight dental blocks (5 x 5 mm²) with polished enamel surfaces were randomly assigned to 7 treatment groups (n=14), as follows: without bleaching and storage in artificial saliva (control); 10% CP; 10% CP + 0.05% calcium; 10% CP + 0.1% calcium; 10% CP + 0.2% calcium; 10% CP + 0.2% fluoride; and 10% CP + 0.5% fluoride. During 14 days, enamel surfaces were daily exposed to a 6-h bleaching regimen followed by storage in artificial saliva. Surface microhardness was measured before (baseline), during (7th day), immediately after bleaching (14th day) and 1 week post bleaching. Data were analyzed by two-way ANOVA and Tukey's test (p<0.05). All treatments reduced SM significantly during the bleaching cycle (7th day), immediately after bleaching (14th day) and 1 week post bleaching, compared to baseline and to the unbleached control group. In conclusion, in spite of the addition of calcium and fluoride, all bleaching treatments affected the enamel surface microhardness.

The purpose of this study was to investigate the effect of pH of different adhesive systems on the polymerization of a chemically cured composite resin (Adaptic - AD), by means of tensile bond strength testing. The adhesive systems tested were: ARM, Prime &amp; Bond 2.1 (PB), Scotchbond Multi Purpose (SMP) and Single Bond (SB). Bond strength at the resin/adhesive system/resin interface was assessed. Five groups (n=5) were formed, according to following configuration: G1: AD/ARM/AD; G2: AD/PB/AD; G3: AD/SMP/AD; G4: AD/SB/AD; G5: AD/AD (no adhesive). A two-mold stainless steel matrix with a cone-shaped opening (1-mm-thick; 4 mm in diameter) was used to obtain resin discs. AD resin was inserted into the first mold, left-self curing and an adhesive layer was applied onto resin surface and light-cured. The second mold was assembled over the first and was filled with the resin. After 10 min, this setting was loaded in tension in a universal testing machine running at a crosshead speed of 0.5 mm/min. Data were submitted to one-way ANOVA and Tukey's test (p<0.05). Bond strength means (kgf) were: G1: 15.23 ± 4.1; G2: 0.00 ± 0.0; G3: 16.96 ± 2.4; G4: 10.08 ± 2.7; G5: 15.44 ± 0.9. There were statistically significant differences (p<0.05) between G2-G1; G2-G3; G2-G4; G4-G1; G4-G3. The systems with the lowest pHs (PB and SB) yielded the lowest bond strength. The findings of this in vitro study demostrates that the pH of adhesive systems influences the polymerization and bond strength of chemically cured resin materials. The low pH simplified adhesive systems showed distinct degrees of incompatibility with the chemically cured resin, when compared to the conventional adhesive systems.