Carlos Roberto Colombo Robazza

In vitro evaluation of the antimicrobial activity of endodontic sealers

The purpose of this study is to evaluate the antimicrobial activity of the endodontic sealers: N-Rickert, Sealapex, AH Plus, Mineral Trioxide Aggregate (MTA) and portland cement. The Agar diffusion method was used in plates previously inoculated with the following microorganisms: C. albicans, S. aureus, E. faecalis, E. coli. The diameters of microbial inhibition zones were measured after 24 hours of incubation in kiln at 37 degrees C. According to the methodology used, it was possible to conclude that only the sealers AH Plus and N-Rickert presented antimicrobial activity against C. albicans, S. aureus, and E. coli; no antimicrobial activity in MTA, Sealapex and portland cement was observed. N-Rickert presented the largest inhibition zones varying from 8 to 18 mm, and the microorganism E. faecalis was resistant against all sealers tested.

In vivo qualitative analysis of the biocompatibility of different cyanoacrylate-based adhesives

Cyanocrylates have been widely used in the medical and dental fields for several years. In Dentistry, cyanoacrylates have been used for suturing, pulp capping, as retrofilling material in endodontic surgeries, and as cervical plug for pulpless teeth bleaching. The biocompatibility of these adhesives has been the topic of many researches and subcutaneous implantation is an effective methodology for these studies. The present study evaluated the biocompatibility of three different cyanoacrylate-based adhesives. Thirty-six Wistar rats were used, divided into four groups of 9 animals each: A (control)--distilled water, B--cyanoacrylate ester (Super Bonder), C - n-butyl-cyanoacrylate (Histoacryl) and D--alpha-cyanoacrylate (Three Bond). The materials were dispensed in sponges of polyvinyl chloride, the animals were incised and the sponges were inserted in the subcutaneous tissue and sutured. Each group was sub-divided according to the time of sacrifice of the animals: 7, 21 and 45 days. Subjective analysis of the histologic material showed that all groups presented some degree of irritability, but the inflammatory reaction decreased with the experimental time in all groups. Group D showed an inflammatory reaction which was closer to that of the control group and was considered to have good biocompatibility. Groups B and C were similar and presented more aggressive inflammatory reactions when compared to the control group. Based on the results, it was concluded that alpha-cyanoacrylate (Three Bond) was the most biocompatible adhesive because it caused the lowest levels of inflammation.

Influence of different volumes of EDTA for final rinse on smear layer removal

OBJECTIVE The aim of this study was to analyze the influence of different volumes of 17% EDTA for final rinse on smear layer removal on the different areas of the root canal. STUDY DESIGN Forty single-rooted teeth were instrumented using rotary instruments. The teeth were divided into 3 test groups according to the EDTA volume for final rinse (5 mL, 10 mL, 15 mL) and 1 control group (10 mL of 1% sodium hypochlorite). The roots were axially split into halves, and the smear layer removal from the canals was determined under scanning electron microscope. The data were analyzed using Kruskal Wallis and Dunn tests. RESULTS The 3 experimental groups showed no statistical difference (P > .05); however, when the test groups were compared to the control group statistically significant differences were found (P < .01). The root canal wall surfaces of teeth in the control group showed the presence of heavy smear layer through the entire length of the root canals. The other groups showed mainly smear layer-free surfaces or a small amount of debris. When coronal, middle and apical thirds were compared, there was no statistically significant difference (P > .05). CONCLUSIONS Based on the results, it appears that a final rinse with 5 mL of EDTA per canal provides good smear layer removal, with root canal walls free of debris and mostly open dentinal tubules in all areas.

Análise espectrofotométrica e visual do clareamento dental interno utilizando laser e calor como fonte catalisadora

This experiment aimed at evaluating, in vitro, the chromatic alteration of dental crowns submitted to internal bleaching. Color alterations were evaluated by means of spectrophotometric analysis and visual observation, at the following experimental phases: initial reading (LI), after-darkening reading (LE), immediate after-bleaching reading (LC), bleaching checked after 15 days (LC15) and after 30 days (LC30). After finding the values of L* (luminosity), a* and b* (shade and saturation), which made it possible to quantify the chromatic alterations of the specimens, color differences (deltaE ) were assessed by means of the CIE Lab Program. The statistical analysis of the results did not reveal any significant difference between conventional bleaching and bleaching activated by Er:YAG laser. No statistical difference was observed between the results after 15 and 30 days, for both experimental groups.

Influence of Er:YAG laser irradiation on apical sealing of four different sealers.

The sealing of the root canal system is of fundamental importance for successful endodontic treatment. To obtain an adequate apical seal, many factors must be considered such as the presence of smear layer and the sealer applied. After canal preparation, this layer must be removed because it prevents close contact between the dentinal walls and the sealing material. The goal of this study was to evaluate the sealing ability of four different sealers after smear layer removal with either 17% EDTA-T irrigation or Er:YAG laser irradiation of 46 teeth. The canals were sealed with four different sealers: Sealapex, Ketac Endo, AH Plus and N-Rickert. The method for smear layer removal did not influence apical sealing. AH Plus and N-Rickert allowed less dye leakage when compared to Sealapex and Ketac Endo.

Correlation between clinical and histopathological diagnoses in periapical inflammatory lesions.

AIM   The purpose of the present study was to evaluate the correlation between clinical and histopathological diagnoses of periapical inflammatory lesions, focusing mainly on cystic conditions. METHODS   Files dating from 1998 to 2006 at the Oral Pathology Laboratory, School of Dentistry, Alfenas Federal University, Brazil, were reviewed to identify cases with histopathological diagnoses of periapical inflammatory lesions. A total of 1788 files were analyzed, and 255 cases were identified with clinical diagnoses of periapical inflammatory lesions. RESULTS   The most prevalent clinical diagnosis was apical periodontal cyst (59%), followed by periapical granuloma (20%), and dentoalveolar abscess (2%). After histopathological analysis, 53% of the cases represented apical periodontal cyst, 42% periapical granuloma, and 5% dentoalveolar abscess. CONCLUSIONS   The outcomes of the present study show a high prevalence of periapical cysts among periapical inflammatory lesions. Moreover, this study highlights the importance of histopathological evaluation for the correct diagnosis of periapical inflammatory lesions.

Association between dental anomalies and malocclusion in Brazilian orthodontic patients

Developmental dental anomalies have been associated with different malocclusions in various populations. This study verified this association in Brazilian non-syndromic orthodontic patients. The prevalence of dental anomalies was evaluated by examining 2,052 pretreatment records of orthodontic patients. Panoramic radiographs, study designs, intraoral photographs and medical history were collected in order to identify hypodontia, hyperdontia, microdontia, macrodontia, taurodontism, transposition, impaction, and ectopia. Epidemiological data and classification of malocclusion were also obtained. Data were analyzed using chi-square and Fishers exact test (P < 0.05), and the prevalence ratio was obtained from cases that had a significant association between anomaly and malocclusion. The results showed that 27.4% of the patients evaluated had some dental anomaly, and most of them were white women aged 11-20 years. Ectopia, microdontia, impaction, and hypodontia were more prevalent in patients with Class I malocclusion. Macrodontia was the only anomaly associated with Class II division 1. Impaction was associated with Class III malocclusion, at a 1.84-times higher prevalence. In conclusion, impaction was correlated with Class I malocclusion; macrodontia showed association with Class II division 1; and impaction and ectopia were associated with Class III malocclusion in Brazilian orthodontic patients. (J Oral Sci 58, 75-81, 2016).