Antimicrobial activity, toxicity and accumulated hard-tissue debris (AHTD) removal efficacy of several chelating agents.

AIM: To evaluate the antimicrobial, toxicity and cleaning effectiveness of ethylenediaminetetraacetic acid (EDTA) and maleic acid (MA) alone and combined with cetrimide (CTR). METHODOLOGY: Cytotoxic and genotoxic effects were assessed on Chinese hamster cells V79 using the MTT, clonogenic and micronucleus assays, respectively. The bacterial inhibitory and bactericidal concentrations (MIC and MBC, respectively) were determined on a strain of Enterococcus faecalis. Antimicrobial tests were performed on a biofilm model after treatment with the chelating agents by using a biofilm eradication concentration (MBEC) and confocal laser scanning microscope (CLSM) assays. Quantification of cell biomass and percentage of live and dead cells in the biomass were assessed for each group. The percentage reduction of accumulated hard-tissue debris (AHTD) after root canal preparation and final irrigation protocols was evaluated by micro-CT. Statistical tests of one-way analysis of variance (anova), Bonferroni test, Kruskal-Wallis test, Dunn's multiple comparison test and Wilcoxon matched-pairs signed-rank tests were used. RESULTS: Cetrimide alone as well as in combination with EDTA and MA at dilutions of 1/10 and 1/100 was significantly more toxic as compared to untreated controls (P < 0.001). All tested mixtures were nontoxic at a dilution of 1/1000. EDTA retained a weak inhibitory and bactericidal effect against planktonic cells, whilst MA inhibited cells growth and killed 99.9% of the cells when diluted. CTR revealed the most prominent effect, being inhibitory and bactericidal, also when diluted. Cetrimide alone or combined with EDTA was able to remove, respectively, 40% (P < 0.01) and 60% (P < 0.001) of the entire biomass after 1 min. Conversely, MA alone and in combination with CTR did not have a significant effect on biomass reduction. After final irrigation, the AHTD volume was significantly decreased in all groups (P < 0.05). EDTA + CTR and MA + CTR were associated with a significant reduction in the percentage of AHTD on the entire root canal compared to the same solutions without surfactant. CONCLUSIONS: 7% MA was less cytotoxic in comparison with 17% EDTA. The addition of cetrimide to EDTA and MA removed accumulated hard-tissue debris effectively from the canal walls and increased their antimicrobial activity when compared to the same solutions without detergents.

Prevalence of vertical root fractures in teeth planned for apical surgery. A retrospective cohort study.

AIM: To evaluate retrospectively the prevalence of vertical root fractures (VRFs) in a cohort of patients during apical surgery and the factors possibly associated with VRF. METHODOLOGY: The sample consisted of 944 root filled teeth belonging to 768 patients (49.3% males and 50.7% females; mean age 43.5 ± 11.2 years, range 22-68 years), consecutively referred for endodontic surgery over a six-year period. All patients underwent a clinical assessment of their signs and symptoms. Periapical radiographs of teeth that were candidates for endodontic surgery were taken. Sixty-eight teeth with VRF were identified. Vertical root fractures were identified in pre-surgical screenings in 32 cases (47.1%), and these did not undergo surgery. Another 36 cases of VRF were noted during the intervention for root-end resection. The influence of posts, post type, tooth type, periodontal probing defects, spontaneous pain, sinus tract and follow-up duration was assessed using a logistic regression analysis. RESULTS: Vertical root fractures occurred significantly more frequently (P < 0.001) when a post was present (61 VRF out of 377 teeth with post, prevalence 16.2%) than in teeth without a post (1.2%). Threaded posts and cast posts were significantly more involved in VRF than fibre, silica or carbide posts (P < 0.001). Most fractures (80.9%) occurred 1-5 years after root canal treatment. Sinus tracts, probing defects and spontaneous pain were significantly more associated with VRF cases than with nonfractured teeth. CONCLUSIONS: In the present group of teeth, the major risk for VRF was represented by posts retained by actively engaging the canal via mechanical design (thread) or by frictional fit (cast).

[Enamel laser conditioning before sealant application].

The purpose of this study was to investigate the advantages offered by enamel laser conditioning before sealants application. 150 teeth of 50 patients were subdivided randomly into three groups. In each patient one tooth was etched with 37% orthophosphoric acid for 30 seconds, a second one with Er:YAG laser and orthophosphoric acid for 30 seconds and a third one exclusively with laser beam. Checks of the integrity of sealants applied were made at 3, 6, 12 months. The group treated with laser and orthophosphoric acid showed the best retention scores after 3, 6, 12 months. Enamel laser conditioning before sealants application reduced sealants fractures and loss during the observation time span.

Periapical endodontic surgery: a 3-year follow-up study.

AIM: To monitor the outcome of periradicular surgery in a group of teeth treated with microsurgical technology and ultrasonic root-end preparation. METHODOLOGY: One hundred and twenty-eight teeth with failed conventional root canal treatment were included. The surgical procedure was completed using ultrasonic retrotips and a zinc oxide-EBA (Super Seal, Ogna Pharmaceuticals. Milan, Italy)-reinforced material was used to seal the root end cavities. Lesions were examined radiologically at 1. 3. 6. 12, 24 and 36-month intervals. Radiographs were independently analysed according to a previously published classification. RESULTS: Eight teeth were extracted due to fracture or perforations undetected radiologically: these cases were excluded from the study. Of the 120 teeth examined. the overall success rate was 92.5%; 94 healed with complete bone filling of the surgical cavity, 17 were considered to have healed by apical scar formation, four demonstrated uncertain healing and five were considered failures. Eighty of 120 teeth examined had successfully healed from a radiological point of view within 12 months. No differences in outcome occurred between anterior, premolar and molar teeth. Although all failures occurred in teeth with posts, no statistically significant difference was noted (Mann-Whitney U-test, P = 0.37). CONCLUSION: Modern surgical endodontic procedures associated and ERA (Super Seal, Ogna Pharmaceuticals, Milan, Italy) root end fillings were successful over 3 years in 92.5% of cases.

[Effects of sterilization and disinfection on mechanical properties of Sentalloy springs]. / Effetti della sterilizzazione e della disinfezione sulle proprietà meccaniche delle molle Sentalloy.

The Authors evaluated mechanic characteristics of open and close titanium coils after two cycles of simulated usage. Coils undergone to thermic autoclaving didn't show any substantial variation in the forces offered compared to those only disinfected, authorizing reusage with igienic guarantees.

[Evaluation of a new technique for binding orthodontic wires]. / Valutazione di una nuova tecnica di piegatura dei fili ortodontici.

The Authors examined to SEM modifications induced by two different bending procedures on orthodontic wires. Changes observed in the group made by orthodontic pliers lacked in the group bended by the machine. Further dinamometric checks will be made to assure that improvements in the mechanical properties of II order bends correspond to phenomena described.

[Treatment of polymerized resins. A new method]. / Trattamento delle resine polimeriche. Nuova metodica.

The resins used at present to prepare removable orthodontic equipment have surface characteristics which do not always correspond to the operator's requirements. The Authors are proposing a new methodology of treatment of the orthodontic products which will improve the outlook, the hygienic aspect and quite probably its byocompatibility.

[The new titanium wires: mechanical characteristics and therapeutic indications]. / I nuovi fili al titanio: caratteristiche meccaniche e indicazioni terapeutiche.

In recent years, orthodontic therapy has been able to make use of a rich, new generation of materials: titanium arches (Sentalloy- Nitinol-Beta Titanium) represent one of the most interesting acquisitions in this field. The Authors, have studied the most important mechanical characteristics in order to define elective clinical application.

[Clinical evaluation of a new mouthwash during orthodontic therapy]. / Valutazione clinica di un nuovo collutorio durante terapia ortodontico.

The purpose of this clinical study was to value the efficacy of a new mouthwash (Oradyne-Z), with an antiseptic agent, alkyl-dimethyl-benzyl-ammonium-saccarinate, against the formation of bacterial oral plaque, in patients during orthodontic treatment. The test procedure was based on observation of 24 subjects (male and female, aged 14 to 50) and divided into 3 equal groups (group A, B and C) during orthodontic therapy. In six (6) weeks, the first group (A), used Oradyne-Z mouthwash, the second group used a placebo solution (B) ant the third (C), used Chlorhexidine mouthwash. The comparison of the results obtained in this clinical and statistical study, confirms the efficacy of Oradyne-Z and chlorhexidine solutions, against supra-gengival plaque. On the contrary no specific result about antiseptical effects, was observed against subgengival oral plaque. The reduction of gengival clinical indices and periodontal pocket dept, was only connected to the scaling and root-planning treatment.