Influence of chlorhexidine digluconate on biocompatibility of cements: Morphological and immunohistochemistry analysis.

In this study, the in vivo biocompatibility was evaluated by using conventional ionomer cements modified with Chlorhexidine (CHX) in different time intervals. In total, 105 male Wistar rats were randomized into seven groups: control, groups M, M10, M18 and groups RL, RL10, RL18 (M-Meron and RL-RivaLuting, and added CHX-10% and CHX-18%, respectively). Histological analyses of inflammatory infiltrate and collagen fibers, and immunohistochemistry of CD68+ for macrophages (MOs) and multinucleated giant cells (MGCs) were performed. Data were analyzed using the Kruskal-Wallis and Dunn (p < .05) tests. Intense inflammatory infiltrate was demonstrated in Group Riva CHX-18% within 7 and 15 days (p < .05), without differences after 30 days. For collagenization, healing of the groups was compatible with that of control in 15 and 30 days (p > .05). Immunomarking of CD68+ was more significant in the groups with higher concentration of CHX. There was significant difference in quantity of MGCs in groups with 18% CHX, Meron (p = .001) in 7 days, and in Riva at 30 days (p = .001). Significant difference was also found in quantities of MOs in Groups Meron and Riva in 7 days (p = .001), and only in Riva at 15 and 30 days (p = .001). The cements with addition of CHX demonstrated biocompatibility with tissues. Riva CHX-18% had the most effect on cells of the inflammatory process but showed satisfactory tissue repair. RESEARCH HIGHLIGHTS: The concentration of 18% chlorhexidine was shown to be biocompatible with tissues; the slow release of chlorhexidine by the cements could significantly prolong its antibacterial effect on the oral medium.

Antimicrobial, mechanical and biocompatibility analysis of chlorhexidine digluconate-modified cements.

BACKGROUND: The focus of this study was to evaluate the antimicrobial, mechanical properties and biocompatibility of glass ionomer (GICs) modified by Chlorhexidine (CHX). MATERIAL AND METHODS: For biocompatibility, 105 male Wistar rats were used, divided into 7 groups (n=15): Group C (Control,Polyethylene), Groups M, M10, M18, and Groups RL, RL10, RL18 (M-Meron and RL-Riva Luting: conventional, and modified with 10%, and 18% CHX, respectively). The tissues were analyzed under optical microscope for different cellular events and time intervals. Antibacterial effect and Shear Bond Strength Test (SBST) were also analyzed. Biocompatibility was analyzed by the Kruskal-Wallis and Dunn tests; SBST one-way ANOVA and Tukey test (P<0.05). For the antibacterial effect, the Kruskal-Wallis and Friedman, followed by Dunn (P<0.05) tests were used. RESULTS: Morphological study of the tissues showed inflammatory infiltrate with significant differences between Groups C and RL18, in the time intervals of 7(P=0.013) and 15(P=0.032) days. The antimicrobial effects of the cements was shown to be CHX concentration-dependent (P=0.001). The SBST showed no significant difference between the Groups of Meron cement (P=0.385), however, there was difference between Group RL and Groups RL10 and RL18 (P=0.001). CONCLUSIONS: The addition of CHX did not negatively influence the SBST. Meron-CHX-10% was the most biocompatible, and Riva-CHX-18% had more influence on the inflammatory process and presented slower tissue repair. Key words:Glass ionomer, chlorhexidine, biocompatibility, antimicrobial properties, microscope.

Effect of degree of conversion on in vivo biocompatibility of flowable resin used for bioprotection of mini-implants.

OBJECTIVE: To test the hypothesis that there is no difference between the biocompatibility and degree of monomer conversion of flowable resins used as bioprotective materials of orthodontic mini-implants. MATERIALS AND METHODS: Forty-eight male Wistar rats were divided into four groups (n  =  12). Group Control (polyethylene), Group Wave, Group Top Comfort, and Group Filtek. The animals were sacrificed after time intervals of 7, 15, and 30 days and tissues were analyzed under optical microscopy for inflammatory infiltrate, edema, necrosis, granulation tissue, multinucleated giant cells, and collagen formation. The degree of conversion was evaluated by the Fourier method. Biocompatibility and degree of conversion were evaluated by the Kruskal-Wallis and Dunn tests, and analysis of variance and the Tukey test, respectively (P < .05). RESULTS: An intense inflammatory infiltrate was observed on the seventh day, with Groups Top Comfort and Filtek differing statistically from Group Control (P  =  .016). Edema, necrosis, granulation tissue, and giant cells showed greater expressiveness at 7 days, without statistical difference between them (P > .05). For the presence of collagen fibers, Group Top Comfort was shown to differ statistically from Group Control (P  =  .037) at 15 days and from Groups Filtek and Control (P  =  .008) at 30 days. Monomer conversion ranged from 62.3% in Group Top Comfort at 7 days to 79.1% in Group Filtek at 30 days. CONCLUSIONS: The hypothesis was rejected. The resin Top Comfort demonstrated lower tissue repair capacity with a lower number of collagen fibers compared with Filtek and Wave resins. The resin Top Comfort showed the lowest conversion values during the experiment.

Anteroposterior and vertical changes in skeletal class II patients treated with modified Thurow appliance.

The aim of this study was to evaluate the post-treatment anteroposterior and vertical alterations in skeletal Class II malocclusion with different maxillary patterns in patients treated with modified Thurow appliance. Forty-five patients (22 girls and 23 boys) with skeletal Class II and angle SN.GoGn ≤ 35 and different maxillary patterns (n = 15), as follows: retrusive (SNA<80°), normal (SNA = 80°- 84°) or protrusive (SNA>84°) maxilla; mean age 9 years at pre-treatment (T1) and 9 years and 10 months at post-treatment (T2), were treated with modified Thurow cervical traction appliance, with expander screw and extraoral face bow with 10° to 20° fold in relation to the intraoral arch. Force of 500 gf was applied and use for 12 to 14 h/day, with fortnightly adjustments. Analysis of variance ANOVA followed by post-hoc Tukey and Kruskal-Wallis test, followed by Mann-Whitney were used (α = 5%). In changes obtained from stage T1 to T2, no statistically significant differences were found among the groups Protrusive, normal and retrusive maxilla for the variables SNB, SN.GoGn, 1.NA, overjet, overbite and Class II discrepancy (right and left) (p>0.05). Angular measurements SNA and ANB in the protrusive maxilla group were significantly greater than in the normal and retrusive maxilla groups (p<0.01). However, in the normal maxilla group these values did not differ significantly from those of the retrusive maxilla group (p>0.05). Within the limits of this study, it may be concluded that the modified Thurow cervical traction appliance was efficient for the correction of skeletal Class II irrespective of the maxillary pattern. The mandible had no significant rotation during treatment.