Giampiero Rossi-Fedele

Evaluation of the antimicrobial effect of super-oxidized water (Sterilox®) and sodium hypochlorite against Enterococcus faecalis in a bovine root canal model

Ideally root canal irrigants should have, amongst other properties, antimicrobial action associated with a lack of toxicity against periapical tissues. Sodium hypochlorite (NaOCl) is a widely used root canal irrigant, however it has been shown to have a cytotoxic effect on vital tissue and therefore it is prudent to investigate alternative irrigants. Steriloxs Aquatine Alpha Electrolyte® belongs to the group of the super-oxidized waters; it consists of a mixture of oxidizing substances, and has been suggested to be used as root canal irrigant. Super-oxidized waters have been shown to provide efficient cleaning of root canal walls, and have been proposed to be used for the disinfection of medical equipment. Objective To compare the antimicrobial action against Enterococcus faecalis of NaOCl, Optident Sterilox Electrolyte Solution® and Steriloxs Aquatine Alpha Electrolyte® when used as irrigating solutions in a bovine root canal model. Methodology Root sections were prepared and inoculated with E. faecalis JH2-2. After 10 days of incubation the root canals were irrigated using one of three solutions (NaOCl, Optident Sterilox Electrolyte Solution® and Steriloxs Aquatine Alpha Electrolyte®) and subsequently sampled by grinding dentin using drills. The debris was placed in BHI broth and dilutions were plated onto fresh agar plates to quantify growth. Results Sodium hypochlorite was the only irrigant to eliminate all bacteria. When the dilutions were made, although NaOCl was still statistically superior, Steriloxs Aquatine Alpha Electrolyte® solution was superior to Optident Sterilox Electrolyte Solution®. Conclusion Under the conditions of this study Steriloxs Aquatine Alpha Electrolyte® appeared to have significantly more antimicrobial action compared to the Optident Sterilox Electrolyte Solution® alone, however NaOCl was the only solution able to consistently eradicate E. faecalis in the model.

Use of a bottle warmer to increase 4% sodium hypochlorite tissue dissolution ability on bovine pulp

The aim of this study was to evaluate the tissue dissolution ability of 4% sodium hypochlorite at increasing temperatures with the use of a baby bottle warmer. Twenty pieces of bovine pulp tissue from freshly extracted incisors and canines were weighted and randomly distributed among four groups in accordance to the exposure to 4% sodium hypochlorite at different temperatures: group C--room temperature (20.5 degrees C--control); group T1--45 degrees C; group T2--60 degrees C; group T3--75 degrees C. The samples were placed within test tubes when the solution reached the desired temperature. Time taken for the dissolution was recorded. One-way anova with logarithmical transformation and Duncan post-hoc was used (P = 0.05). There was a statistically significant increase in speed of pulp dissolution from group T1 to group C and from groups T2 and T3 to group T1; group T2 and T3 displayed similar dissolution speeds.

A Review of Tooth Discoloration after Regenerative Endodontic Therapy.

INTRODUCTION The American Association of Endodontists clinical considerations for regenerative therapy (April 2015) advise of the risk of the possible adverse effect of staining of teeth. It is widely acknowledged that before these guidelines were developed there was no standardized protocol for regenerative therapy, and different approaches using different materials have been reported. The purpose of this review was to undertake a systematic review of published cases to determine the incidence of reported discoloration and examine whether there was any particular association with any material. METHODS A PubMed search was performed using key words for regenerative endodontic therapy consistent with prior published systematic reviews. RESULTS There were 80 studies identified with 379 teeth treated. Many of the studies did not report on the presence or absence of discoloration. It was noted that there was a strong association of discoloration with the use of triple antibiotic paste containing minocycline; however, discoloration was also noted when other materials were used. Unfortunately, bleaching of stained teeth was not predictably achieved in some studies. CONCLUSIONS The use of triple antibiotic paste with minocycline as the intracanal medicament should be reconsidered. Either calcium hydroxide or the double antibiotic paste of metronidazole and ciprofloxacin may limit discoloration. Mineral trioxide aggregate was also associated with discoloration. However, there is little evidence of an alternative superior material as a coronal barrier. Because discoloration is a patient-orientated outcome, further research should document and identify the incidence of discoloration in regenerative endodontic treatment.

Assessment of Root Canal Filling Removal Effectiveness Using Micro–computed Tomography: A Systematic Review

Introduction The removal of obturation materials from the root canal system is a primary objective in root canal retreatment procedures. This systematic review aims to discuss the effectiveness of different instrumentation procedures in removing root‐canal filling materials assessed by micro‐computed tomography. Methods An electronic search in PubMed and major endodontic journals was conducted using appropriate key words to identify investigations that examined the effectiveness of obturation material removal assessed by micro‐computed tomography. Results Among 345 studies, 22 satisfied the inclusion criteria. Seven studies compared hand instrumentation with Nickel‐Titanium rotary or reciprocating systems. Three studies investigated rotary systems, and another three studies explored reciprocation. Eight studies compared rotary systems and reciprocation in removing filling materials from the root canal system. Other factors, such as the role of solvents and irrigant agitation, were discussed. Conclusions The application of different instrumentation protocols can effectively, but not completely, remove the filling materials from the root canal system. Only hand instrumentation was not associated with iatrogenic errors. Reciprocating and rotary systems exhibited similar abilities in removing root filling material. Retreatment files performed similarly to conventional ones. Solvents enhanced penetration of files but hindered cleaning of the root canal. The role of irrigant agitation was determined as controversial. HighlightsOrthograde retreatment requires the removal of previous root canal filling materials.Twenty‐two studies were included in the systematic review.None of the protocols investigated was able to fully remove root canal filling materials.Reciprocating and rotary methods have a similar ability in removing root filling material.Only hand instrumentation was not associated with iatrogenic errors.Hybrid protocols are likely to improve cleanliness.

Bovine pulp tissue dissolution ability of HealOzone®, Aquatine Alpha Electrolyte® and sodium hypochlorite

The aim of this study was to evaluate the bovine pulp tissue dissolution ability of HealOzone, Aquatine Alpha Electrolyte® and 0.5% sodium hypochlorite, used alone or in combination. Thirty bovine pulp fragments were weighed, divided into six groups and placed individually in Eppendorf tubes containing the tested solution until total dissolution occurred. The groups were: G1: saline (negative control), G2: Aquatine Alpha Electrolyte®, G3: 0.5% NaOCl (positive control), G4: Saline + HealOzone, G5: 0.5% NaOCl + HealOzone, G6: Aquatine Alpha Electrolyte® + HealOzone. HealOzone was activated for 2 min with a #6 cup covering the test tube opening on a fixed platform. Two blinded observers using 2× loupes magnification assessed the samples continuously for the first 2 h, and then every hour for the next 8 h. Dissolution speed was calculated by dividing pulp weight by dissolution time (mg min(-1) ). G3 (NaOCl) and G5 (NaOCl + HealOzone) dissolved the pulp tissue completely. The mean dissolution speed for G3 was 0.396 mg min(-1) (SD 0.032) and for G5 was 0.775 mg min(-1) (SD 0.2). Students t-test showed that G5 dissolved bovine pulp tissue faster than G3 (P = 0.01). Only groups containing sodium hypochlorite dissolved pulp tissue, whilst HealOzone enhanced speed of dissolution.

D-amino acids reduce Enterococcus faecalis biofilms in vitro and in the presence of antimicrobials used for root canal treatment

Enterococcus faecalis is the most frequent species present in post-treatment disease and plays a significant role in persistent periapical infections following root canal treatment. Its ability to persist in stressful environments is inter alia, due to its ability to form biofilms. The presence of certain D-amino acids (DAAs) has previously been shown to reduce formation of Bacillus subtilis biofilms. The aims of this investigation were to determine if DAAs disrupt biofilms in early and late growth stages for clinical E. faecalis strains and to test their efficacy in disrupting E. faecalis biofilms grown in sub-minimum inhibitory concentrations of commonly used endodontic biocides. From thirty-seven E. faecalis strains, the ten “best” biofilm producers were used to test the ability of a mixture containing D-leucine, D-methionine, D-tyrosine and D-tryptophan to reduce biofilm growth over a period of 24, 72 and 144 hours and when compared to their cognate L-Amino Acids (LAAs). We have previously shown that sub-MIC levels of tetracycline and sodium hypochlorite promotes biofilm growth in clinical strains of E. faecalis. DAAs were therefore tested for their effectiveness to reduce biofilm growth in the presence of sub-minimal concentrations of sodium hypochlorite (NaOCl-0.031%) and Odontocide™ (0.25% w/v), and in the presence of Odontopaste™ (0.25% w/v). DAAs significantly reduced biofilm formation for all strains tested in vitro, while DAAs significantly reduced biofilm formation compared to LAAs. The inhibitory effect of DAAs on biofilm formation was concentration dependent. DAAs were also shown to be effective in reducing E. faecalis biofilms in the presence of Odontopaste™ and sub-MIC levels of NaOCl and Odontocide™. The results suggest that the inclusion of DAAs into current endodontic procedures may reduce E. faecalis biofilms.

Ultrasonography in the diagnosis of bone lesions of the jaws: a systematic review

The diagnostic use of ultrasonography in dentistry and maxillofacial surgery has previously been described in the literature. Considering that ultrasonography may be useful for the diagnosis of bone lesions of the jaws, a systematic review was carried out to examine the evidence. This review determined that ultrasonography has been used effectively for the diagnosis of infective and/or inflammatory lesions, cysts, nonodontogenic tumors, odontogenic tumors, and arteriovenous malformations and for the differential diagnosis of lesions of endodontic origin, compared with the gold standard of histologic analysis. Ultrasonography may be a viable adjunct to other special tests for the diagnosis of intraosseous lesions of the jaws, as it is noninvasive and does not involve ionizing radiation exposure of the patient.

The quality of information on the Internet on orthodontic retainer wear: a cross-sectional study

Objectives The objectives of this study were to assess the accessibility, usability, reliability and quality of information on the Internet written for the lay public about orthodontic retainers, and to elucidate the different retention protocols encouraged. Design A cross-sectional, observational study. Setting Online, using a computer connected to the Internet in Australia. Methods Two search terms; ‘orthodontic retainer’ and ‘how long should someone wear a retainer after their braces are removed?’ were entered alternatively into five search engines. Twenty results for each search term per search engine that fulfilled the inclusion criteria were evaluated in terms of accessibility, usability, reliability and quality of information using the LIDA and DISCERN instruments, ensuring there were no internal or cross-search engine duplicates. Any information about frequency and duration of retainer wear was also collected. Results Two hundred different websites were identified and assessed. The median overall LIDA score was 72%, corresponding to a moderate quality level. The median total DISCERN score was 47%. Twenty-two websites recommended patients adhere to the specific protocol prescribed to them by their practitioner. There were 45 (22.5%) and 28 (14%) websites advising indefinite use of removable and bonded retainers respectively. Conclusions Information about retainers on the Internet is easily accessible and usable, though the quality of the content is generally of a moderate level. However, the information is not always accurate and reliable. Both full-time and part-time wear of removable retainers was suggested over greatly varying time periods. Indefinite wear of removable and bonded retainers was also advocated.

Effect of Superoxidized Water and Sodium Hypochlorite, Associated or Not with EDTA, on Organic and Inorganic Components of Bovine Root Dentin

INTRODUCTION This study aimed to evaluate the effects of Sterilox (Sx), a superoxidized water, 5% and 2% sodium hypochlorite (5NaOCl and 2NaOCl), and 17% EDTA (E) on the organic and inorganic components of bovine dentin. METHODS Eighty bovine incisors were randomly divided into 8 groups (n = 10): 5NaOCl, 5NaOCl + E, 2NaOCl, 2NaOCl + E, Sx, Sx + E, E alone, and distilled water (H2O). Root canal instrumentation was performed by using the corresponding irrigant. The apical 15 mm was longitudinally sectioned into 2 fragments, one for light microscopy analysis in slides stained with picrosirius red (organic component) and the other for scanning electron microscopy analysis (inorganic component). Scores data obtained in the light microscopy analysis were submitted to the Kruskal-Wallis test, followed by multiple comparisons test (P < .05). Scanning electron microscopy images were analyzed descriptively. RESULTS The chemical solution 5NaOCl had a greater effect on the organic component of dentin in area and depth than 2NaOCl. The chemical solutions 5NaOCl + E, 5NaOCl and 2NaOCl + E caused the greatest change in the collagenous organic matrix near the root canal lumen. The chemical solution 2NaOCl showed similar behavior to Sx, associated or not with E, promoting more superficial disorganization of collagen in a smaller area. Demineralization was observed in all groups in which E was used. However, areas of erosion and open dentinal tubules were detected only when it was combined with NaOCl. CONCLUSIONS Five percent NaOCl promoted the most extensive damage to the organic component of dentin, and when associated to EDTA, dentinal erosion could be seen. Considering these specific aspects, 2% NaOCl and Sx had milder effects on bovine root dentin.

Some factors influencing the stability of Sterilox®, a super-oxidised water

Super-oxidised waters, particularly Sterilox®, have been suggested for the disinfection of dental unit water lines and dental impression materials owing to their antimicrobial efficacy. One of the previously suggested characteristics is their short shelf life. The purpose of this investigation was to understand the effect of storage conditions on Sterilox®s stability. Eight bottles (four completely full, four half-full) of freshly prepared solution were divided into four groups and subsequently stored by being either exposed to or protected from sunlight. The chlorine concentration was monitored using chlorine test strips until the concentration reached zero, or until the thirteenth week. Statistically significant differences between the groups exposed to sunlight and the non-exposed groups (p <0.001) were found. The mean loss of chlorine per day for the non-exposed samples was 1.01 mg/L, whilst the mean for the exposed samples was 2.42 mg/L. The presence of air did not affect the chlorine decomposition in the bottles. The results of this investigation indicate that when the solution is exposed to sunlight, the decrease of chlorine starts at day 4, whilst for the groups sheltered from sunlight, the process started after day 14. Therefore, Sterilox® solutions appear to be more stable than previously surmised.