R. J. G. De Moor

Effectiveness of different laser systems to kill Enterococcus faecalis in aqueous suspension and in an infected tooth model

AIM To assess the antibacterial action of laser irradiation (Nd:YAG, KTP), photo activated disinfection (PAD) and 2.5% sodium hypochlorite (NaOCl) on Enterococcus faecalis, in an aqueous suspension and in an infected tooth model. METHODOLOGY Root canals of 60 human teeth with single straight canals were prepared to apical size 50, autoclaved, inoculated with an E. faecalis suspension and incubated for 48 h. They were randomly allocated to four treatment and one control groups. After treatment, the root canals were sampled by flushing with physiological saline, and the number of surviving bacteria in each canal was determined by plate count and solid phase cytometry. The same experimental or control treatments were completed on aqueous suspensions of E. faecalis, and the number of surviving bacteria was determined in the same way. RESULTS In aqueous suspension, PAD and NaOCl resulted in a significant reduction in the number of E. faecalis cells (P < 0.001), whilst Nd:YAG or KTP had no effect. In the infected tooth model, only the PAD and NaOCl treated teeth yielded significantly different results relative to the untreated controls (P < 0.001). CONCLUSIONS The laser systems as well as PAD were less effective than NaOCl in reducing E. faecalis, both in aqueous suspension and in the infected tooth model.

Evaluation of Nd:YAG and Er:YAG irradiation, antibacterial photodynamic therapy and sodium hypochlorite treatment on Enterococcus faecalis biofilms

AIM To compare the antimicrobial efficacy of two-high power lasers (Nd:YAG and Er:YAG) and two commercial antimicrobial photodynamic therapy (aPDT) systems with that of sodium hypochlorite (NaOCl) action on Enterococcus faecalis biofilms grown on dentine discs. METHODOLOGY Enterococcus faecalis biofilms were grown on dentine discs in a microtiter plate, incubated for 24 h and subjected to the following treatments: aPDT (Denfotex and Helbo system), Er:YAG laser irradiation (2940 nm, 50 mJ or 100 mJ, 15 Hz, 40 s), Nd:YAG laser irradiation (1064 nm, 2 W, 15 Hz, 40 s) and immersion in 2.5% (w/v) NaOCl for 1, 5, 10 and 30 min. Surviving bacteria were harvested, and the number of CFU per disc was determined by plate counting. RESULTS Significant reductions (anova, P ≤ 0.05) in viable counts were observed for aPDT (Helbo) (2 log(10) reduction), Er:YAG irradiation using 100 mJ pulses (4.3 log(10) reduction) and all NaOCl treatments (>6 log(10) reduction). NaOCl (2.5%) for 5 min effectively eliminated all bacteria. aPDT (Denfotex), Er:YAG irradiation using 50 mJ pulses and Nd:YAG treatment caused a reduction in the viable counts of <1 log(10) unit; these results were not significantly different from the untreated controls. CONCLUSION Within the limitations of this particular laboratory set-up, NaOCl was the most effective in E. faecalis biofilm elimination, while Er:YAG laser treatment (100 mJ pulses) also resulted in high reductions in viable counts. The use of both commercial aPDT systems resulted in a weak reduction in the number of E. faecalis cells. Nd:YAG irradiation was the least effective.

Undergraduate curriculum guidelines for endodontology.

Earlier editions of the ESE undergraduate curriculum guidelines for Endodontology were published in 1992 and 2001 (International Endodontic Journal 25, 169–72; 34, 574–80) and formed a benchmarking reference for dental schools and regulatory bodies. Despite much technological advance and the publication of quality guidelines for endodontic treatment (European Society of Endodontology 2006), studies published during the last decade have continued to show disappointing technical standards of root canal treatment in European populations (Eriksen et al. 2002, Segura-Egea et al. 2004, Tavares et al. 2009, Gencoglu et al. 2010, Peters et al. 2011). Longitudinal observational studies have also reinforced the relationship between treatment quality and persistent disease (Eckerbom et al. 2007, Kirkevang et al. 2007). Although a limited number of European countries have recognized endodontics as a speciality, there is no doubt that the vast proportion of endodontic procedures will continue to be undertaken by general dental practitioners. Evidence suggests that many general practitioners lack sufficient knowledge of the factors important in determining the outcome of root canal treatment (Bjørndal et al. 2007) and that basic principles are often disregarded (Peciuliene et al. 2009). Some of this may reflect the acquisition of foundational knowledge and skills during undergraduate training, where standards remain highly variable (Eleftheriadis & Lambrianidis 2005, Er et al. 2006, Sonntag et al. 2008, Burke et al. 2009, Kelbauskas et al. 2009, Khabbaz et al. 2010). It is therefore important to ensure that undergraduate training is undertaken to a level that encourages deep understanding of the factors important in determining clinical outcome. It is beyond the scope of this pre-amble to provide a detailed critique of all aspects of endodontic practice, but the example of root canal treatment serves to illustrate the motivation of the European Society of Endodontology in promoting standards of scientific education and clinical training across a broad undergraduate curriculum in Endodontology. This includes but is not limited to diagnostic and treatment procedures for the prevention and management of pulpal and periradicular disease, and for the preservation, restoration and monitoring of pulpally compromised teeth that would otherwise be lost. It is implicit that the procedures defined should be exercised within a model of holistic, evidence-based patient care and should be undertaken to support the oral and general health of patients. This document represents a guideline for an undergraduate curriculum and cannot be exhaustive. The underlying principle must be that a minimum level of competence is reached prior to graduation and that an ethos of continuing professional development is instilled in the graduate.

Dental and oral complications of lip and tongue piercings

Piercing of the tongue and perioral regions is an increasingly popular expression of body art, with more patients coming in for a routine check-up with tongue and/or lip piercings. Several complications of oral piercing have been reported, some of which are life-threatening. In the present clinical survey the prevalence of both tongue and lip piercing complications in oral health was assessed in a group of 50 patients. The most common dental problem registered was chipping of the teeth, especially in association with tongue piercing. Gingival recession was seen as a result of lip piercing with studs. Postprocedural complications included oedema, haemorrhage and infection. Therefore, dentists and oral and maxillofacial surgeons should be given more authority to advise patients with oral and facial piercings or those who plan to acquire this type of body art.

The Short-term Fluoride Release of a Hand-mixed vs. Capsulated System of a Restorative Glass-ionomer Cement

The present study investigated whether variability in fluoride release was reduced by use of a capsulated system as compared with a hand-mixed system based on the same qualitative and quantitative glass-ionomer formulation. Five operators independently prepared five disks of each type of glass-ionomer restorative filling material. The amount of fluoride released in water by each specimen after 1, 2, 3, 7, and 14 days was determined. The variance and the mean value of the fluoride release at a given time were independent of the operator, regardless of the glass-ionomer system considered. However, the variance and the mean value of the fluoride release at a given time were considerably greater for the capsulated system than for the hand-mixed system. A regression analysis further showed that the cumulative amount of fluoride released, [F], as a function of the time t conformed to [F] = a[1- exp (-bt)] + ct0.5 for each glass-ionomer specimen, suggesting the simultaneous occurrence of two processes. Whereas the parameter b was the same for the hand-mixed and capsulated system and was independent of both a and c, the latter parameters were positively correlated. Moreover, the values for a and c were significantly greater for the capsulated system. On the basis of these results, it is concluded that the mixing process drastically influences the short-term as well as the long-term fluoride release.

Long‐term sealing ability of Resilon apical root‐end fillings

AIM To evaluate ex vivo the long-term sealing ability of the SE Resilon Epiphany system as an apical root-end filling material. METHODOLOGY A total of 60 standardized horizontal bovine root sections were divided into three groups filled with either gutta-percha with AH 26, tooth-coloured mineral trioxide aggregate (MTA) or Resilon pellets with Epiphany SE, and submitted to capillary flow porometry at 48 h, 1 and 6 months to assess the minimum, mean flow and maximum pore diameters. Results of the different materials and results by material and time were analysed statistically using nonparametric tests; the level of significance was set at 0.05. RESULTS Resilon had smaller pore diameters than gutta-percha and MTA at 48 h and smaller mean flow and maximum pore diameters than gutta-percha and MTA at 1 month. At 6 months Resilon had larger minimum pore diameters than gutta-percha. Although not always statistically significant, the minimum, mean flow and maximum pore diameters of gutta-percha and MTA diminished with time. This was not the case for Resilon, where the same parameters increased. CONCLUSIONS All materials leaked at all times. Resilon performed better than gutta-percha and MTA in the short-term, but the seal of MTA and gutta-percha improved over time whereas the seal of Resilon deteriorated. It is critical to evaluate the performance of materials in the long-term contrary to most studies which are short-term.

The use of laser Doppler flowmetry in paediatric dentistry

BACKGROUND: An early determination of pulpal vitality is crucial with respect to a correct differential diagnosis of revascularisation or necrosis and its treatment. REVIEW: Sensibility tests (cold, heat, electrical pulp test) in combination with radiographs are commonly promoted. However these tests are arbitrary, based on sensations and therefore not always reliable. In such situations registration of pulpal blood flow will be advantageous. The most studied and well documented method for registration of blood circulation is laser Doppler flowmetry (LDF) which is typified as a non-invasive technique with direct and objective registrations. In this article blood flow, LDF and its characteristics, the advantages and disadvantages of the methods and the latest developments regarding LDF is described. CONCLUSION: Despite there being a low implementation of LDF in dentistry to date, this should become one of the basic techniques for clinical use in paediatric dentistry.

Safety Irradiation Parameters of Nd:YAP Laser Beam for Endodontic Treatments: An In Vitro Study

Objective. Nd:YAP laser has several potentialities of clinical applications in endodontics. The aim of our study is to determine the safety range of irradiation parameters during endodontic application of Nd:YAP laser that can be used without damaging and overheating the periodontal tissue. Material and Methods. Twenty-seven caries-free single-rooted extracted human teeth were used. Crowns were sectioned to obtain 11 mm root canal length. Temperature increases at root surfaces were measured by a thermocouple during Nd:YAP laser irradiation of root canals at different energy densities. Canal irradiation was accomplished with a circular and retrograde movement from the apex until the cervical part of the canal during 10 seconds with an axial speed of 1 mm/s. Each irradiation was done in a canal irrigated continuously with 2.25% NaOCl solution. Results. Periodontal temperature increase depends on the value of energy density. Means and standard deviations of temperature increases at root surfaces were below 10°C (safe threshold level) when the average energy densities delivered per second were equal to or below 4981 J/cm2 and 9554 J/cm2, respectively, for irradiations using a fiber diameter of 320 μm and 200 μm. Conclusions. Within the limitations of this study and under specific irradiation conditions, Nd:YAP laser beam may be considered harmless for periodontal tissues during endodontic applications.

Wortelperforaties: etiologie, diagnostiek, behandeling en prognose

Wortelperforatie is een onaangename complicatie die extractie van een gebitselement noodzakelijk kan maken. Accidentele wortelperforaties komen bij 2 tot 12 % van de wortelkanaalbehandelde gebitselementen voor. Een redelijk gunstige prognose kan verkregen worden door het niet-chirurgisch herstellen van het defect, met een algemeen succes van meer dan 70 %, ongeacht het type herstelmateriaal. Biokeramische cementen blijken evenwel tot een hoger succes te leiden. Elf preoperatieve factoren, i.e. geslacht, aantal wortels, elementtype, gibitselementen in de maxilla versus mandibula, perforatiegrootte, type behandeling (primair – herbehandeling), tekenen en symptomen, radiolucentie naast de perforatie, apicale parodontitis, duur van het perforatieherstel (meer of minder dan een maand) en de locatie/positie van de perforatie ten opzichte van het crestaal botniveau, beinvloeden de prognose. Het succes van niet-chirurgisch herstel wordt als volgt significant beinvloed: (1) maxillaire gebitselementen hebben een betere genezingskans dan mandibulaire elementen, (2) wortels zonder preoperatieve radiolucente zone in de buurt van de perforatie hebben eveneens een betere prognose.

Irrigatie en reiniging van het wortelkanaal: de noodzaak om irrigantia te activeren

Het mislukken van een wortelkanaalbehandeling is in het merendeel van de gevallen te wijten aan onvoldoende reiniging en desinfectie van het wortelkanaal. Enerzijds is er de keuze van het spoelmiddel, anderzijds moet driemensionale verspreiding plaatsvinden van het irringans (zeker in de zones die niet door instrumenten bereikt kunnen worden). Een enkele spoelvloeistof blijkt niet voldoende te zijn. De gouden standaard blijft natriumhypochloriet (oplossen van weefsels en desinfectie). Een tweede standaard is tegenwoordig ethyleendiaminotretra-azijnzuur (oplossen van smeerlaag en debris, openzetten van dentinetubuli en de verbindingen tussen kanalen zoals de ishtmus). De technologische vooruitgang van het afgelopen decennium heeft geleid tot de ontwikkeling van nieuwe activatie-/agitatieapparatuur en de introductie van activatie-/agitatietechnieken, die een betere driedimensionale verspreiding van het irrigans mogelijk maken dan met handirrigatie. Men maakt onderscheid tussen manueel en machinaal aangestuurde agitatiesystemen. Deze blijken uiteindelijk te resulteren in een betere reiniging van het wortelkanaal. Het is de vraag wat nu het best is.