Regeneração óssea em alvéolos de ratos após enxerto de osso bovino inorgânico medular e biocerâmica sintética densa / Alveolar bone regeneration in rats after grafting of anorganic bovine bone and thick synthetic bioceramic

Introdução: é incerto se o uso de biomateriais em cirurgiasparendodônticas é capaz de facilitar ou induziro processo de regeneração óssea. Esse estudo analisou,comparativamente, os efeitos do preenchimento de alvéolosde ratos com osso bovino inorgânico medular euma biocerâmica sintética densa no processo de regeneraçãoóssea. Material: Quarenta e oito ratos albinosWistar foram distribuídos, aleatoriamente, em três grupos,que, após a extração dentária, tiveram os alvéolos preenchidosda seguinte forma: GI (n = 12) coágulo (controle);GII (n = 18) osso bovino inorgânico medular; GIII (n = 18)biocerâmica sintética densa. As amostras foram obtidasem 7, 15 e 30 dias pós-cirurgia. Foram realizadas análisesmicroscópicas quantitativas do infiltrado inflamató-rio, densidade fibroblástica, densidade angioblástica eneoformação óssea. Os dados foram submetidos ao testede Kruskal-Wallis (α < 0,05) para detectar diferenças entreos grupos no mesmo intervalo de tempo. Resultados:apesar de terem sido detectadas algumas diferenças entreos grupos experimentais e o controle para infiltrado inflamatórioe densidade angioblástica em 07 dias, e formaçãoóssea em 15 dias, no período de 30 dias o processo de reparofoi semelhante para todos os grupos. Conclusões:não houve diferença entre os dois materiais empregados,os quais não atrasaram o processo de regeneração óssea,e, se usados em cirurgias parendodônticas, podem atuarcomo materiais osteocondutores e osteopreenchedoresnos grandes defeitos ósseos.

Efficacy of the NaviTip FX irrigation needle in removing calcium hydroxide from root canal.

OBJECTIVE: To evaluate the effectiveness of the NaviTip FX, brush-covered irrigation needle, in removing calcium hydroxide from the root canal. STUDY DESIGN: Thirty single-rooted teeth were randomly divided into three groups: A - irrigation with a hypodermic needle inserted as far as possible without binding and activation with #30 K-type file; B - Irrigation with a hypodermic needle without activation; C - irrigation with NaviTip FX needle. Sodium hypoclorite 1% was used in irrigation. The root canals were examined trough scanning electron microscopy. Calcium hydroxide removal was recorded at 1, 5, and 10mm from the working length (WL) and the data were analysed using one-way ANOVA test (p<0.05). RESULTS: NaviTip FX and hypodermic needle activated with #30K-type file showed lower score at 10 and 5mm with no significant difference between them. Comparison within groups did not show significant differences. All groups showed significantly better smear layer removal at 5 and 10 mm from the WL. CONCLUSION: The apical third (1mm) of the root canal was found to be the most critical site for Ca(OH)2 removal. Key words:Calcium hydroxide, irrigation, scanning electron microscope, NaviTip FX.

Physical properties and interfacial adaptation of three epoxy resin-based sealers.

INTRODUCTION: The aim of the study was to evaluate the radiopacity, solubility, flow, film thickness, setting time, and adaptation to the root canal walls of 3 epoxy resin-based sealers: AH Plus, Acroseal, and Adseal. METHODS: Physical tests were performed following American National Standards Institute/American Dental Association's requirements. For interfacial adaptation analysis, 30 maxillary canines were shaped by using ProTaper instruments. The specimens were divided into 3 groups (n = 10): group 1, AH Plus; group 2, Acroseal; and group 3, Adseal. The sealers were mixed with rhodamine B dye, and the canals were filled by using the lateral compaction technique. The percentage of gaps and voids area was calculated at 2, 4, and 6 mm levels from the apex. Statistical evaluation was performed by using analysis of variance for physical analysis and nonparametric Kruskal-Wallis and Dunn tests for interfacial adaptation (P < .05). RESULTS: No statistical differences were found for adaptation, percentage of voids, solubility, flow, and film thickness among the sealers (P > .05). AH Plus was significantly more radiopaque (P < .05). For the setting time, there were statistical differences among all the studied sealers (P < .05). CONCLUSIONS: AH Plus, Acroseal, and Adseal presented similar root canal adaptation, solubility, flow, and film thickness. Statistical differences were found for radiopacity and setting time (P < .05).

Antimicrobial effects of calcium hydroxide and chlorhexidine on Enterococcus faecalis.

INTRODUCTION: Endodontic treatment is commonly based on nonspecific elimination of intraradicular microorganisms. Although some authors prefer single-visit root canal operations for endodontic treatment, several studies have shown the importance of intracanal medication between sessions to kill microorganisms that biomechanical preparations alone cannot achieve. The purpose of this study was to evaluate the efficacy of calcium hydroxide Ca(OH)(2) and chlorhexidine gel on the elimination of intratubular Enterococcus faecalis. METHODS: Human uniradicular teeth contaminated with E. faecalis were treated with Ca(OH)(2), 2% chlorhexidine gel, Ca(OH)(2) plus 2% chlorhexidine gel, or saline (0.9% NaCl) as a negative control. Samples obtained at a depth of 0 to 100 mum and 100 to 200 mum from these root canal preparations were analyzed for bacterial load by counting the number of colony-forming units (CFUs) and bacterial viability using fluorescence microscopy. RESULTS: A significant decrease in the number of CFUs and the percentage of viable E. faecalis was observed after treatment with either Ca(OH)(2) or chlorhexidine when compared with the control group. Additionally, chlorhexidine gel had a significantly higher antimicrobial efficacy as measured by the number of CFUs and the percentage of viable cells than Ca(OH)(2). No differences were observed between the antimicrobial properties of chlorhexidine gel with and without the addition of Ca(OH)(2). CONCLUSION: Both Ca(OH)(2) and chlorhexidine have antimicrobial effects on E. faecalis. Chlorhexidine had increased antimicrobial activity when compared with Ca(OH)(2.) Ca(OH)(2) combined with chlorhexidine showed similar antimicrobial activity to chlorhexidine alone.

Heat-killed Enterococcus faecalis alters nitric oxide and CXCL12 production but not CXCL8 and CCL3 production by cultured human dental pulp fibroblasts.

INTRODUCTION: Fibroblasts are the most abundant cells in dental pulp. To investigate their capacity to produce the chemokines CCL3, CXCL8, and CXCL12 as well as nitric oxide (NO), we evaluated the production of these mediators in supernatants of cultured human dental pulp fibroblasts (HDPF) stimulated by heat-killed Enterococcus faecalis (HKEF). METHODS: Primary cultures of HDPF were stimulated with medium alone or HKEF (1:1, 10:1, or 100:1 bacteria:fibroblast) for 1, 6, and 24 hours. Chemokines and NO were assessed through enzyme-linked immunosorbent assay and Griess reaction, respectively. Statistical analysis was performed by using analysis of variance and Tukey post test. RESULTS: CCL3 was not detected, whereas constitutive CXCL8 was not affected. Production of CXCL12 was increased at 1 and 6 hours, and NO was increased at the concentration of 1:1 bacteria:fibroblast at 24 hours. Viability and proliferation assays did not reveal cell number differences. CONCLUSIONS: These findings demonstrate that heat-killed E. faecalis is able to increase production of CXCL12 and NO by HDPF.

Evaluation of the radiopacity of some commercial and experimental root-end filling materials.

OBJECTIVE: The aim of the present study was to evaluate the radiopacity of 5 root end filling materials (white MTA Angelus, MTA Bio, light-cured MTA, Sealepox RP, and Portland cement clinker with bismuth oxide and calcium sulfate). METHOD: Five specimens, 10 mm in diameter and 1 mm in thickness according to specification ISO 6876:2001 were fabricated from each material and radiographed using Insigth occlusal films close to a graduated aluminum step-wedge (2 to 16 mm in thickness). Radiographs were digitized and compared to the aluminum step-wedge. The radiographic density data were converted into millimeters of aluminum (mm Al), using the Digora 1.51 software. Results were evaluated statistically using the analysis of variance (ANOVA) followed by Tukey test. The level of significance was set at 5% (P <.05%). RESULTS: Radiopacity values ranged from 1.21 mm Al (light-cured MTA) to 6.45 mm Al (MTA Angelus). Comparison between materials showed significant difference (P < .05) between MTA Angelus and all other materials, between Sealepox RP and MTA Bio, and between light-cured MTA and Portland cement clinker. Light-cured MTA was significantly less radiopaque than all other materials. No significant difference (P > .05) was found between MTA Bio and Portland cement clinker. CONCLUSIONS: All retrograde filling materials evaluated showed greater radiopacity than dentin. All the materials, except light-cured MTA met the minimum radiopacity standards of 3 mm Al recognized by the ISO 6876:2001 and ADA n.57.

Evaluation of precision of length determination with 3 electronic apex locators: Root ZX, Elements Diagnostic Unit and Apex Locator, and RomiAPEX D-30.

OBJECTIVE: The aim of this study was to perform a comparative analysis of precision of 3 apex locators: Root ZX, Elements Diagnostic Unit and Apex Locator, and RomiAPEX D-30. STUDY DESIGN: Forty extracted single-rooted human teeth were selected. After endodontic access, measurement of the anatomical tooth length was visually performed by insertion of a K-file size 10 until its tip could be observed at the apical foramen with aid of a light microscope at 8x magnification. Following, the teeth were placed in a plastic box with alginate and electronically measured with the 3 apex locators at 1-mm short of the apical foramen. RESULTS: The results revealed a precision rate of 97.5% for Root ZX, 95% for Elements Diagnostic Unit and Apex Locator, and 92.5% for RomiAPEX D-30, with no statistically significant difference between them (chi-square test, P > .05). CONCLUSION: The results confirm that all these electronic devices can accurately determine the root canal length within 1 mm from the apical constriction.

Influence of embedding media on the assessment of electronic apex locators.

Third-generation electronic apex locators for root canal length determination are very reliable and are not subject to interference from the contents of the canals. This study compared the effectiveness of different embedding media for in vitro assessment of electronic apex locators. The tooth lengths of 30 extracted human mandibular central incisors were measured by introducing a size 15 K-file fitted with a silicone stop into the canal until its tip appeared through the apical foramen; the distance between the tip and stop was measured. The teeth were placed in cylindrical polyethylene tubes filled with different embedding media (1% agar, gelatin, alginate, saline, and flower sponge soaked in saline), and electronic reading was performed with the Root ZX device. Data were statistically assessed by the analysis of variance (ANOVA) and Tukey tests at a significance level of 5%. Despite the lack of statistically significant difference among the media, the flower sponge was the only medium in which the file surpassed the apex in some measurements.

Evaluation of apical cavity preparation with a new type of ultrasonic diamond tip.

This study evaluated the time, occurrence of fracture, and quality of apical cavity preparation with three different ultrasonic diamond tips: Satelec, Trinity, and a new type, CVD (chemical vapor deposition), using scanning electron microscopy (SEM) analysis. Thirty human single-rooted premolars were selected, submitted to apicectomy, and prepared with ultrasonic tips; impressions were then obtained. The presence of fractures was evaluated on the impressions, and the quality of preparation was evaluated by SEM analysis of teeth and scoring by two examiners. The group prepared with the CVD tips exhibited the shorter preparation time and did not present fractures. There was no statistically significant difference in the quality of preparation for the three tips. The three brands of ultrasonic tips produced adequate grinding without altering the morphology of the apical foramen.

Use of MTA and intracanal post reinforcement in a horizontally fractured tooth: a case report.

Root fracture is one of the consequences of dental traumatisms. The possibility of saving the fractured tooth depends on the level of the fracture and also on pulp vitality. This case report describes the use of MTA in association to an intracanal post to reinforce a maxillary central incisor with horizontal root fracture in its cervical third.

Evaluation of tissue response to MTA and Portland cement with iodoform.

OBJECTIVE: The aim of this study was to evaluate the biocompatibility of Portland cement with the addition of iodoform, compared to MTA (ProRoot). STUDY DESIGN: Eighteen Wistar albino rats were divided into 3 groups of 6 animals each. Polyethylene tubes were filled either with freshly mixed MTA or Portland cement mixed with iodoform (20% wt/wt) and implanted subcutaneously. An empty tube served as control. After 7, 30, or 60 days, the implants together with the surrounding tissues were removed in blocks. Sections were evaluated for the presence and thickness of a fibrous capsule, presence of granulation tissue, and the severity of inflammatory response. Data were submitted to nonparametric statistical analysis with individual comparisons between groups at a significance level of P < 0.05. RESULTS: There were no differences between inflammatory responses at 7 and 30 days. After 60 days from surgical removal, there was significantly more tissue reaction to the MTA and Portland cement compared to the control group. CONCLUSION: There were no significant differences regarding inflammatory responses between MTA and Portland cement with iodoform after 7, 30, or 60 days. After 60 days, the fibrous capsule around the Portland cement appeared more organized than tissue surrounding MTA implants. After 60 days, there was still a significantly increased tissue reaction to the 2 cements compared to the empty polyethylene tubes.