RCAAP Repository

The aim of this study was to verify the ability of different adhesive materials to prevent microleakage in bonded amalgam restorations. Standard cavities were prepared in both buccal and lingual surfaces of 35 bovine incisors. The gingival wall was located in cementum/dentin and the occlusal wall in enamel. Teeth (n=35) were divided into 5 groups, according to material employed (one glass-ionomer cement, two resin cements, one adhesive system, and Copalex varnish as a control). Following restoration, the teeth were submitted to thermal cycling. The teeth were subsequently immersed in methylene blue dye and sectioned to allow assessment of microleakage. Non-parametric statistical analysis indicated that all materials demonstrated less leakage than the control group (p<0.01). No leakage was found using the resin-modified glass-ionomer cement, which was significantly different from the other adhesive materials (p<0.05). Leakage in enamel was lower than in cementum/dentin margins. It was concluded that bonded amalgam was an effective technique, since all materials prevented microleakage in enamel and cementum/dentin, when compared to the control group, except Panavia in cementum/dentin margins.

The purpose of this study was to compare the effect of a self-etching primer and a non-rinse conditioner with the effect of a conventional adhesive system on the penetration depth in dentin of human teeth, using scanning electronic microscopy (SEM). Fifteen human third molar teeth were sectioned into 2 pieces. All pieces were flattened with grade 600 to 1200 silicon carbide paper and divided into 6 groups: group 1 - Prime &amp; Bond NT (NT), negative control; group 2 - 37% phosphoric acid + Prime &amp; Bond NT (PANT), positive control; group 3 - Non-rinse Conditioner (NRC) + Prime &amp; Bond NT (NRCNT); group 4 - NRC + Prime &amp; Bond 2.1 (NRCPB); group 5 - NRC + Scotchbond MP (NRCSB); group 6 - Prompt L-Pop (PLP). All teeth were covered with Dyract AP. The tooth fragments were decalcified, and its resin replicas were evaluated by SEM by three previously standardized examiners. The penetration was scored from 0 (no penetration) to 3 (maximum penetration). The Kruskal-Wallis and Mann-Whitney U tests (p<0.05) showed three statistically homogeneous groups: {NT, NRCPB, NRCSB and PLP}, {NRCNT} and {PANT}. The authors concluded that the self-etching primer and the non-rinse conditioner provide a lower penetration depth in human tooth dentin than the conventional adhesive system.

The objective of this research was to determine if gutta-percha points with calcium hydroxide [Ca(OH)2] improve the apical seal after root canal filling and if the master point does it alone. Human single recently extracted teeth were biomechanically prepared and the root canals filled by the lateral condensation technique with ZOE and gutta-percha points, with or without calcium hydroxide. The teeth were placed into a 2% methylene blue solution in a vacuum environment for 24 h after which they were processed for stereomicroscope evaluation. Better results were observed with the teeth filled with gutta-percha points with calcium hydroxide (p=0.01). We conclude that these new points make a better apical seal and that these results can also be obtained with the calcium hydroxide master point associated with regular ones (p=0.05).

The aim of the present study was to analyze the antimicrobial properties of five endodontic sealers: Endo Fill, Endomethasone, Endomethasone N, Sealer 26 and AH-Plus, against the following microorganisms: Candida albicans, Staphylococcus aureus, Enterococcus faecalis, Streptococcus sanguis and Actinomyces naeslundii. The sealers were tested immediately, 24 h, 48 h and 7 days after manipulation.The direct contact method through the observation of the microbial growth in liquid medium and the agar diffusion test were used to evaluate the antimicrobial properties of the sealers. The results, in both methodologies used, showed that immediately after manipulation, Endo-Fill and Endomethasone demonstrated the highest antimicrobial activity, with no statistically significant difference between them. Sealer 26 demonstrated the lowest antimicrobial activity. At all other times after manipulation, there were no statistically significant differences among all the sealers tested. In conclusion, none of the sealers totally inhibited the growth of the microorganisms. Furthermore, the antimicrobial activity of each sealer decreased with time and was dependent upon the microbial susceptibility to them.

This study evaluated the cleaning capacity of Profile .04 instruments with different concentrations of NaOCl solutions on flattened root canals. Twenty central mandibular incisors were divided into 4 groups: Group I: 0.5% NaOCl; Group II: 1% NaOCl; Group III: 5% NaOCl; Group IV: distilled and deionized water. After chemomechanical preparation, the teeth were submitted to histological preparation and morphometric analysis. Morphometric analysis showed that the 5% NaOCl was significantly more efficient in cleaning the root canal than 0.5% NaOCl and distilled water, which had the lowest levels of cleaning of the root canals (p<0.01).

Gingival inflammation is clinically characterized by gingival redness, swelling and increased tendency of bleeding of the soft tissue. Bacterial biofilm is the etiological agent. If, at this stage, the bacterial biofilm is removed and appropriate control methods are applied, remission of gingival inflammation occurs. This study evaluated the effectiveness of a single session of ultrasonic prophylaxis for the reduction of gingivitis in an adolescent population using the Plaque Index (PI) and Gingival Index (GI). The study sample consisted of 15 male adolescent students selected at a dentist's office of a public high school. Prior to treatment (baseline), plaque index (PI) and bleeding on probing (BOP) were recorded. The patients then received oral hygiene instructions and ultrasonic prophylaxis. Follow-up exams were made 15 and 30 days after the ultrasonic prophylaxis, again recording PI and BOP. The data were analyzed by the Student's t-test for dependent samples. Correlation analysis between presence of biofilm and bleeding on probing was also made using the Pearson correlation test. There was a statistically significant decrease in the plaque index and bleeding on probing between baseline and examinations at both 15 days and 30 days (p<0.05). However, the difference between the means at 15 and 30 days was statistically similar. The correlation analysis showed correlation between both parameters (p<0.05). The results indicate that a single session of ultrasonic prophylaxis associated to oral hygiene instructions is efficient to reverse gingivitis in adolescents.

Epidemiological studies have shown strong evidence that periodontal disease does not affect all subjects in the same manner. There are subjects and sites with higher risk for disease progression. This study tested parameters to select "a priori" sites and subjects potentially at risk. The data from periodontal clinical examinations of 2273 subjects was used. The clinical loss of attachment was measured in 6 sites per tooth. Using computer software, the patients were distributed into 14 age groups, with intervals of 5 years, from 11 years to greater than 75 years of age. The measure of each site was compared with the average and the median values of the subject age group, with the results indicating site comparative severity (SCS). Three global parameters were calculated: parameter 1 (P1) - percentage of sites with clinical attachment loss > 4 mm; parameter 2 (P2) - percentage of sites with clinical attachment loss > 7 mm; parameter 3 (P3) - percentage of sites with clinical attachment loss surpassing the median value for the age group by 100% or more. There were 1466 (65%) females and 807 (35%) males. Most subjects had P1, P2 and P3 values less than 30%. Parameter 3 allowed a division of the sample similar to that of Parameters 1 and 2, with the advantage of analyzing the subject in relation to his/her age group. It was suggested that the methodology of SCS is useful for selecting a population with a high disease prevalence, and that cut-off lines between 10% and 20% would be appropriate for using Parameter 3.

The aim of this study was to clinically assess the results of treatment for functional posterior cross-bites by means of selective grinding in individuals at the deciduous dentition phase over a period of 12 months. From a total of 1,011 children examined in the 2-to-6-year age bracket, 26 with functional posterior cross-bites were selected. The sample was divided into 2 groups of 13 children each, group 1 receiving the treatment proposed and group 2 serving as the control group. Treatment was followed up by exercises designed to alter the children's muscular memory. The results showed that correction of functional posterior cross-bite was achieved for all the children treated, the correction remaining stable 12 months later. No self-correction of malocclusion occurred among the control group.

The objective of this in vitro study was to evaluate a possible remineralization of human carious dentin by calcium hydroxide. Thirty-nine freshly extracted human permanent and deciduous carious teeth were split into two halves. One half was used as control and the other as experimental. In the latter, a cavity was prepared and the remaining bottom layer of demineralized dentin capped with chemically pure calcium hydroxide. The experimental samples were stored at 37ºC. Time intervals were 2, 4, 6, 8, 10 and 12 weeks. All tooth halves were sawed and ground to plano-parallel sections with a thickness varying from 75 to 117 µm. Qualitative microradiographs showed a qualitative increase in radiopacity of the calcium hydroxide treated samples. Quantitative microradiography showed a statistically significant increase in total mineral content in the experimental samples compared to the control samples. These results indicate an in vitro remineralization of carious dentin by calcium hydroxide.

This study investigated the dimensional stability of denture bases influenced by packing methods, in relation to post-pressing times, in the Clássico acrylic resin which was prepared according to manufacturer recommendations. Forty maxillary wax bases were made and randomly assigned into 2 groups of 20 specimens each according to the conventional and RS system packing methods. In each method, the specimens were subdivided into immediate, 6, 12 and 24 h post-pressing times. The dough of the acrylic resin was packed in metallic flasks and processed in a water bath curing cycle at 74ºC for 9 h. After cooling at room temperature, the bases were removed from the flasks, finished and fixed on stone casts with instantaneous adhesive. The resin base-stone cast sets were transversally sectioned into 3 sections and the base-stone gap measured at 5 points in each section. The data were submitted to ANOVA and Tukey's test, which showed that the RS system had a smaller base distortion compared to conventional packing, with the exception of the 24-h post-pressing time. There was a statistically significant difference between the packing methods only in section C (posterior palatal zone). In the conventional packing method, the immediate and 6 h times demonstrated values with no statistically significant difference between them, as well as between the 12 and 24 h post-pressing times.

The dental and skeletal dimensions of individuals with Class I skeletal pattern in puberty were compared. Eighty patients with Class I malocclusion were selected, independent of the vertical relations (overbite) of the incisors. The sample was divided into 3 groups: normal, short and excessive lower anterior face height, based on facial proportions. The dental and skeletal measurements of the 3 groups were compared among themselves. In the angular measurements, the results showed no correlation in the mandibular plane angle. In the linear measurements, the mandibular length was significantly greater in the group of patients with short lower anterior face height, with a positive correlation among the three groups. The dentoalveolar heights of the incisors had a positive correlation among the three groups in relation to the lower anterior face height, showing that they are responsible for its variation.

Cherubism is a rare benign hereditary fibro-osseous disease involving the mandible and maxilla. We report a case of cherubism in a 10-year-old girl for which the panoramic radiograph was insufficient for diagnosis of the disease. Clinical, histological, and radiological findings were discussed. The CT was taken and it confirmed not only the involvement of the jaws but also of the temporal bone. This was not found in the conventional radiograph.

Oral myiasis is a rare pathology and a risk to the patient's life. Conventional treatment is mechanical removal of the larvae (maggots) one by one, which is painful, distressing, and embarrassing both to the patient and to the dentist. We present a case report of a patient with cerebral palsy that had oral myiasis treated successfully with ivermectin. The use of this antibiotic in humans, its mechanism of action and indications are discussed.

This study aimed to quantify new bone formation in the femurs of diabetic Wistar rats. Over an eight-week period, MTI-MP® implants were evaluated in control rats and in diabetic rats. At several points during this period, various markers for bone deposit were introduced. The material was observed under fluorescent light microscopy. New bone formation in periosteal and cortical regions linked to the implant did not vary significantly between the groups. However, there were significant differences in total new bone formation in the medullar canal and in bone/implant contact area in the medullar portion. Bone deposits attached to the surface of the temporary implants demonstrated that they are biocompatible and capable of osseointegration.

The objective of the present study was to correlate the expression of cyclin D1 with the expression of p21 in 28 cases of oral squamous cell carcinoma (OSCC), as well as to compare the expression of both with a histological graduation of this neoplasm. Immunohistochemistry was used to obtain the expression of cyclin D1 and p21. The results of statistical analysis showed no correlation between the expression of cyclin D1 and p21. Also, there was no correlation between the mean numbers of cyclin D1 positive nuclei and p21 positive nuclei and the histological scores of malignancy. However, the marked expression of cyclin D1 in high-grade tumors supports its role in proliferative activity. In contrast, p21 seems unable to arrest tumor progression in OSCC.

Despite studies concerning toxic reactions related to amalgam components in the literature, few studies have been devoted to evaluate local noxious effects of amalgam tattoos (AT) on biological tissues. In addition, little is known about activation of inflammatory cells by mucosa-implanted amalgam debris. Tissue reaction to AT depends on the particle size. Human leukocyte antigen DR (HLA-DR) is an activation marker of inflammatory cells associated with antigen presentation. Metallothioneins (MT) are proteins involved with metal detoxication, including mercury and silver. The purpose of the present study was to investigate the immunolocalization of HLA-DR and MT in AT with large or powdered particles. Paraffin-embedded AT tissue blocks were sectioned and subjected to immunohistochemistry for HLA-DR and MT localization. The results demonstrated a dense mononuclear inflammatory infiltrate associated with large and powdered debris and positivity for HLA-DR and MT in inflammatory cells. While blood vessel walls and connective fibers impregnated with powdered particles were negative for HLA-DR, they were positive for MT. In addition, wherever epithelial basement membrane impregnation by powdered amalgam particles was observed, a strong positivity for MT was detected. These findings demonstrate that residual elements of AT still have noxious local effects over tissues.

This study was conducted to observe the response of dogs' dental pulp to white mineral trioxide aggregate (MTA) when used as pulp capping material. The pulp of 15 dogs' teeth was experimentally exposed and capped with white MTA. The animals were sacrificed two months later and the specimens were prepared for histomorphological study. The pulp capped with white MTA showed a healing process with complete dentin bridge formation in all samples. In some cases, there was not a tubular dentin shape, but only a structure with an interesting morphological aspect sealing the exposure site. Only 2 specimens exhibited pulp inflammation. In conclusion, the data obtained in this study showed that white MTA has the necessary properties of a pulp capping material.

The aim of this study was to evaluate, histopathologically, the effectiveness of mechanical preparation of root canals using different irrigating solutions in dog teeth filled with LPS after pulpectomy. A total of 120 root canals of 6 mongrel dogs were filled with a solution of LPS after pulpectomy. The irrigating solutions used were saline, 1, 2.5, and 5% sodium hypochlorite, and 2% chlorhexidine. No irrigation was used in the control group. The animals were sacrificed after 60 days and the teeth were fixed and demineralized. Subsequently, serial 6-µm sections were stained with hematoxylin and eosin and Mallory's trichrome for histopathological analysis and Brown-Brenn for verification of bacterial contamination. Analysis showed that the inflammatory infiltrate was statistically less intense in the groups in which the root canals were irrigated with 5% sodium hypochlorite and 2% chlorhexidine. However, none of the irrigating solutions completely inactivated the harmful effects of LPS. Mechanical preparation associated with different irrigating solutions did not completely inactivate LPS.

The present study evaluated, in vitro, the temperature alterations on the external root surface during instrumentation with four different rotary systems. A total of 20 extracted human maxillary lateral incisors were instrumented using either the ProFile, MicroMega, Quantec or K³ systems and the thermal alterations on the root surface were recorded by means of three thermocouples attached to the coronal, middle and apical portions of the root. Mean temperature increases no higher than 0.4ºC ± 1.0ºC (ProFile system) were recorded, which indicates that these instruments are safe for the surrounding periodontal tissues.

The aim of this study was to determine the effect of ultrasonic vibration on the force necessary to remove pre-fabricated and anatomic and cast posts. Two hundred and forty teeth were divided into two groups. In group I, a 0.8-mm metallic pre-fabricated post, Unimetric-Maillefer, was utilized; in group II, cast copper-aluminum alloy posts measuring 0.8, 1.0 and 1.2 mm in diameter were used. The root canals were prepared in three different diameters: 0.8, 1.0 and 1.2 mm, with a length of 10 mm. The posts were cemented with glass monomer cement resulting in 20 specimens for each subgroup. Half of the sample was submitted to ultrasonic vibration for 3 min, while the other half did not receive any vibration. The specimens were submitted to traction in a universal testing machine. The results were analyzed by non-parametric Mann-Whitney U, Wilcoxon and Kruskal-Wallis tests. The application of ultrasonic vibration significantly reduced the retention provided by the glass ionomer cement in the fixation of intracanal posts. The ultrasonic action was effective in both pre-fabricated and anatomic and cast posts. The effectiveness of the ultrasonic vibration was not related to the cementation line or the diameter of the post.